drivers/spi/spi.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 // SPI init/core code
   3 //
   4 // Copyright (C) 2005 David Brownell
   5 // Copyright (C) 2008 Secret Lab Technologies Ltd.
   6
   7 #include <linux/kernel.h>
   8 #include <linux/device.h>
   9 #include <linux/init.h>
  10 #include <linux/cache.h>
  11 #include <linux/dma-mapping.h>
  12 #include <linux/dmaengine.h>
  13 #include <linux/mutex.h>
  14 #include <linux/of_device.h>
  15 #include <linux/of_irq.h>
  16 #include <linux/clk/clk-conf.h>
  17 #include <linux/slab.h>
  18 #include <linux/mod_devicetable.h>
  19 #include <linux/spi/spi.h>
  20 #include <linux/spi/spi-mem.h>
  21 #include <linux/of_gpio.h>
  22 #include <linux/gpio/consumer.h>
  23 #include <linux/pm_runtime.h>
  24 #include <linux/pm_domain.h>
  25 #include <linux/property.h>
  26 #include <linux/export.h>
  27 #include <linux/sched/rt.h>
  28 #include <uapi/linux/sched/types.h>
  29 #include <linux/delay.h>
  30 #include <linux/kthread.h>
  31 #include <linux/ioport.h>
  32 #include <linux/acpi.h>
  33 #include <linux/highmem.h>
  34 #include <linux/idr.h>
  35 #include <linux/platform_data/x86/apple.h>
  36
  37 #define CREATE_TRACE_POINTS
  38 #include <trace/events/spi.h>
  39 EXPORT_TRACEPOINT_SYMBOL(spi_transfer_start);
  40 EXPORT_TRACEPOINT_SYMBOL(spi_transfer_stop);
  41
  42 #include "internals.h"
  43
  44 static DEFINE_IDR(spi_master_idr);
  45
  46 static void spidev_release(struct device *dev)
  47 {
  48         struct spi_device       *spi = to_spi_device(dev);
  49
  50         /* spi controllers may cleanup for released devices */
  51         if (spi->controller->cleanup)
  52                 spi->controller->cleanup(spi);
  53
  54         spi_controller_put(spi->controller);
  55         kfree(spi->driver_override);
  56         kfree(spi);
  57 }
  58
  59 static ssize_t
  60 modalias_show(struct device *dev, struct device_attribute *a, char *buf)
  61 {
  62         const struct spi_device *spi = to_spi_device(dev);
  63         int len;
  64
  65         len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1);
  66         if (len != -ENODEV)
  67                 return len;
  68
  69         return sprintf(buf, "%s%s\n", SPI_MODULE_PREFIX, spi->modalias);
  70 }
  71 static DEVICE_ATTR_RO(modalias);
  72
  73 static ssize_t driver_override_store(struct device *dev,
  74                                      struct device_attribute *a,
  75                                      const char *buf, size_t count)
  76 {
  77         struct spi_device *spi = to_spi_device(dev);
  78         const char *end = memchr(buf, '\n', count);
  79         const size_t len = end ? end - buf : count;
  80         const char *driver_override, *old;
  81
  82         /* We need to keep extra room for a newline when displaying value */
  83         if (len >= (PAGE_SIZE - 1))
  84                 return -EINVAL;
  85
  86         driver_override = kstrndup(buf, len, GFP_KERNEL);
  87         if (!driver_override)
  88                 return -ENOMEM;
  89
  90         device_lock(dev);
  91         old = spi->driver_override;
  92         if (len) {
  93                 spi->driver_override = driver_override;
  94         } else {
  95                 /* Empty string, disable driver override */
  96                 spi->driver_override = NULL;
  97                 kfree(driver_override);
  98         }
  99         device_unlock(dev);
 100         kfree(old);
 101
 102         return count;
 103 }
 104
 105 static ssize_t driver_override_show(struct device *dev,
 106                                     struct device_attribute *a, char *buf)
 107 {
 108         const struct spi_device *spi = to_spi_device(dev);
 109         ssize_t len;
 110
 111         device_lock(dev);
 112         len = snprintf(buf, PAGE_SIZE, "%s\n", spi->driver_override ? : "");
 113         device_unlock(dev);
 114         return len;
 115 }
 116 static DEVICE_ATTR_RW(driver_override);
 117
 118 #define SPI_STATISTICS_ATTRS(field, file)                               \
 119 static ssize_t spi_controller_##field##_show(struct device *dev,        \
 120                                              struct device_attribute *attr, \
 121                                              char *buf)                 \
 122 {                                                                       \
 123         struct spi_controller *ctlr = container_of(dev,                 \
 124                                          struct spi_controller, dev);   \
 125         return spi_statistics_##field##_show(&ctlr->statistics, buf);   \
 126 }                                                                       \
 127 static struct device_attribute dev_attr_spi_controller_##field = {      \
 128         .attr = { .name = file, .mode = 0444 },                         \
 129         .show = spi_controller_##field##_show,                          \
 130 };                                                                      \
 131 static ssize_t spi_device_##field##_show(struct device *dev,            \
 132                                          struct device_attribute *attr, \
 133                                         char *buf)                      \
 134 {                                                                       \
 135         struct spi_device *spi = to_spi_device(dev);                    \
 136         return spi_statistics_##field##_show(&spi->statistics, buf);    \
 137 }                                                                       \
 138 static struct device_attribute dev_attr_spi_device_##field = {          \
 139         .attr = { .name = file, .mode = 0444 },                         \
 140         .show = spi_device_##field##_show,                              \
 141 }
 142
 143 #define SPI_STATISTICS_SHOW_NAME(name, file, field, format_string)      \
 144 static ssize_t spi_statistics_##name##_show(struct spi_statistics *stat, \
 145                                             char *buf)                  \
 146 {                                                                       \
 147         unsigned long flags;                                            \
 148         ssize_t len;                                                    \
 149         spin_lock_irqsave(&stat->lock, flags);                          \
 150         len = sprintf(buf, format_string, stat->field);                 \
 151         spin_unlock_irqrestore(&stat->lock, flags);                     \
 152         return len;                                                     \
 153 }                                                                       \
 154 SPI_STATISTICS_ATTRS(name, file)
 155
 156 #define SPI_STATISTICS_SHOW(field, format_string)                       \
 157         SPI_STATISTICS_SHOW_NAME(field, __stringify(field),             \
 158                                  field, format_string)
 159
 160 SPI_STATISTICS_SHOW(messages, "%lu");
 161 SPI_STATISTICS_SHOW(transfers, "%lu");
 162 SPI_STATISTICS_SHOW(errors, "%lu");
 163 SPI_STATISTICS_SHOW(timedout, "%lu");
 164
 165 SPI_STATISTICS_SHOW(spi_sync, "%lu");
 166 SPI_STATISTICS_SHOW(spi_sync_immediate, "%lu");
 167 SPI_STATISTICS_SHOW(spi_async, "%lu");
 168
 169 SPI_STATISTICS_SHOW(bytes, "%llu");
 170 SPI_STATISTICS_SHOW(bytes_rx, "%llu");
 171 SPI_STATISTICS_SHOW(bytes_tx, "%llu");
 172
 173 #define SPI_STATISTICS_TRANSFER_BYTES_HISTO(index, number)              \
 174         SPI_STATISTICS_SHOW_NAME(transfer_bytes_histo##index,           \
 175                                  "transfer_bytes_histo_" number,        \
 176                                  transfer_bytes_histo[index],  "%lu")
 177 SPI_STATISTICS_TRANSFER_BYTES_HISTO(0,  "0-1");
 178 SPI_STATISTICS_TRANSFER_BYTES_HISTO(1,  "2-3");
 179 SPI_STATISTICS_TRANSFER_BYTES_HISTO(2,  "4-7");
 180 SPI_STATISTICS_TRANSFER_BYTES_HISTO(3,  "8-15");
 181 SPI_STATISTICS_TRANSFER_BYTES_HISTO(4,  "16-31");
 182 SPI_STATISTICS_TRANSFER_BYTES_HISTO(5,  "32-63");
 183 SPI_STATISTICS_TRANSFER_BYTES_HISTO(6,  "64-127");
 184 SPI_STATISTICS_TRANSFER_BYTES_HISTO(7,  "128-255");
 185 SPI_STATISTICS_TRANSFER_BYTES_HISTO(8,  "256-511");
 186 SPI_STATISTICS_TRANSFER_BYTES_HISTO(9,  "512-1023");
 187 SPI_STATISTICS_TRANSFER_BYTES_HISTO(10, "1024-2047");
 188 SPI_STATISTICS_TRANSFER_BYTES_HISTO(11, "2048-4095");
 189 SPI_STATISTICS_TRANSFER_BYTES_HISTO(12, "4096-8191");
 190 SPI_STATISTICS_TRANSFER_BYTES_HISTO(13, "8192-16383");
 191 SPI_STATISTICS_TRANSFER_BYTES_HISTO(14, "16384-32767");
 192 SPI_STATISTICS_TRANSFER_BYTES_HISTO(15, "32768-65535");
 193 SPI_STATISTICS_TRANSFER_BYTES_HISTO(16, "65536+");
 194
 195 SPI_STATISTICS_SHOW(transfers_split_maxsize, "%lu");
 196
 197 static struct attribute *spi_dev_attrs[] = {
 198         &dev_attr_modalias.attr,
 199         &dev_attr_driver_override.attr,
 200         NULL,
 201 };
 202
 203 static const struct attribute_group spi_dev_group = {
 204         .attrs  = spi_dev_attrs,
 205 };
 206
 207 static struct attribute *spi_device_statistics_attrs[] = {
 208         &dev_attr_spi_device_messages.attr,
 209         &dev_attr_spi_device_transfers.attr,
 210         &dev_attr_spi_device_errors.attr,
 211         &dev_attr_spi_device_timedout.attr,
 212         &dev_attr_spi_device_spi_sync.attr,
 213         &dev_attr_spi_device_spi_sync_immediate.attr,
 214         &dev_attr_spi_device_spi_async.attr,
 215         &dev_attr_spi_device_bytes.attr,
 216         &dev_attr_spi_device_bytes_rx.attr,
 217         &dev_attr_spi_device_bytes_tx.attr,
 218         &dev_attr_spi_device_transfer_bytes_histo0.attr,
 219         &dev_attr_spi_device_transfer_bytes_histo1.attr,
 220         &dev_attr_spi_device_transfer_bytes_histo2.attr,
 221         &dev_attr_spi_device_transfer_bytes_histo3.attr,
 222         &dev_attr_spi_device_transfer_bytes_histo4.attr,
 223         &dev_attr_spi_device_transfer_bytes_histo5.attr,
 224         &dev_attr_spi_device_transfer_bytes_histo6.attr,
 225         &dev_attr_spi_device_transfer_bytes_histo7.attr,
 226         &dev_attr_spi_device_transfer_bytes_histo8.attr,
 227         &dev_attr_spi_device_transfer_bytes_histo9.attr,
 228         &dev_attr_spi_device_transfer_bytes_histo10.attr,
 229         &dev_attr_spi_device_transfer_bytes_histo11.attr,
 230         &dev_attr_spi_device_transfer_bytes_histo12.attr,
 231         &dev_attr_spi_device_transfer_bytes_histo13.attr,
 232         &dev_attr_spi_device_transfer_bytes_histo14.attr,
 233         &dev_attr_spi_device_transfer_bytes_histo15.attr,
 234         &dev_attr_spi_device_transfer_bytes_histo16.attr,
 235         &dev_attr_spi_device_transfers_split_maxsize.attr,
 236         NULL,
 237 };
 238
 239 static const struct attribute_group spi_device_statistics_group = {
 240         .name  = "statistics",
 241         .attrs  = spi_device_statistics_attrs,
 242 };
 243
 244 static const struct attribute_group *spi_dev_groups[] = {
 245         &spi_dev_group,
 246         &spi_device_statistics_group,
 247         NULL,
 248 };
 249
 250 static struct attribute *spi_controller_statistics_attrs[] = {
 251         &dev_attr_spi_controller_messages.attr,
 252         &dev_attr_spi_controller_transfers.attr,
 253         &dev_attr_spi_controller_errors.attr,
 254         &dev_attr_spi_controller_timedout.attr,
 255         &dev_attr_spi_controller_spi_sync.attr,
 256         &dev_attr_spi_controller_spi_sync_immediate.attr,
 257         &dev_attr_spi_controller_spi_async.attr,
 258         &dev_attr_spi_controller_bytes.attr,
 259         &dev_attr_spi_controller_bytes_rx.attr,
 260         &dev_attr_spi_controller_bytes_tx.attr,
 261         &dev_attr_spi_controller_transfer_bytes_histo0.attr,
 262         &dev_attr_spi_controller_transfer_bytes_histo1.attr,
 263         &dev_attr_spi_controller_transfer_bytes_histo2.attr,
 264         &dev_attr_spi_controller_transfer_bytes_histo3.attr,
 265         &dev_attr_spi_controller_transfer_bytes_histo4.attr,
 266         &dev_attr_spi_controller_transfer_bytes_histo5.attr,
 267         &dev_attr_spi_controller_transfer_bytes_histo6.attr,
 268         &dev_attr_spi_controller_transfer_bytes_histo7.attr,
 269         &dev_attr_spi_controller_transfer_bytes_histo8.attr,
 270         &dev_attr_spi_controller_transfer_bytes_histo9.attr,
 271         &dev_attr_spi_controller_transfer_bytes_histo10.attr,
 272         &dev_attr_spi_controller_transfer_bytes_histo11.attr,
 273         &dev_attr_spi_controller_transfer_bytes_histo12.attr,
 274         &dev_attr_spi_controller_transfer_bytes_histo13.attr,
 275         &dev_attr_spi_controller_transfer_bytes_histo14.attr,
 276         &dev_attr_spi_controller_transfer_bytes_histo15.attr,
 277         &dev_attr_spi_controller_transfer_bytes_histo16.attr,
 278         &dev_attr_spi_controller_transfers_split_maxsize.attr,
 279         NULL,
 280 };
 281
 282 static const struct attribute_group spi_controller_statistics_group = {
 283         .name  = "statistics",
 284         .attrs  = spi_controller_statistics_attrs,
 285 };
 286
 287 static const struct attribute_group *spi_master_groups[] = {
 288         &spi_controller_statistics_group,
 289         NULL,
 290 };
 291
 292 void spi_statistics_add_transfer_stats(struct spi_statistics *stats,
 293                                        struct spi_transfer *xfer,
 294                                        struct spi_controller *ctlr)
 295 {
 296         unsigned long flags;
 297         int l2len = min(fls(xfer->len), SPI_STATISTICS_HISTO_SIZE) - 1;
 298
 299         if (l2len < 0)
 300                 l2len = 0;
 301
 302         spin_lock_irqsave(&stats->lock, flags);
 303
 304         stats->transfers++;
 305         stats->transfer_bytes_histo[l2len]++;
 306
 307         stats->bytes += xfer->len;
 308         if ((xfer->tx_buf) &&
 309             (xfer->tx_buf != ctlr->dummy_tx))
 310                 stats->bytes_tx += xfer->len;
 311         if ((xfer->rx_buf) &&
 312             (xfer->rx_buf != ctlr->dummy_rx))
 313                 stats->bytes_rx += xfer->len;
 314
 315         spin_unlock_irqrestore(&stats->lock, flags);
 316 }
 317 EXPORT_SYMBOL_GPL(spi_statistics_add_transfer_stats);
 318
 319 /* modalias support makes "modprobe $MODALIAS" new-style hotplug work,
 320  * and the sysfs version makes coldplug work too.
 321  */
 322
 323 static const struct spi_device_id *spi_match_id(const struct spi_device_id *id,
 324                                                 const struct spi_device *sdev)
 325 {
 326         while (id->name[0]) {
 327                 if (!strcmp(sdev->modalias, id->name))
 328                         return id;
 329                 id++;
 330         }
 331         return NULL;
 332 }
 333
 334 const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev)
 335 {
 336         const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver);
 337
 338         return spi_match_id(sdrv->id_table, sdev);
 339 }
 340 EXPORT_SYMBOL_GPL(spi_get_device_id);
 341
 342 static int spi_match_device(struct device *dev, struct device_driver *drv)
 343 {
 344         const struct spi_device *spi = to_spi_device(dev);
 345         const struct spi_driver *sdrv = to_spi_driver(drv);
 346
 347         /* Check override first, and if set, only use the named driver */
 348         if (spi->driver_override)
 349                 return strcmp(spi->driver_override, drv->name) == 0;
 350
 351         /* Attempt an OF style match */
 352         if (of_driver_match_device(dev, drv))
 353                 return 1;
 354
 355         /* Then try ACPI */
 356         if (acpi_driver_match_device(dev, drv))
 357                 return 1;
 358
 359         if (sdrv->id_table)
 360                 return !!spi_match_id(sdrv->id_table, spi);
 361
 362         return strcmp(spi->modalias, drv->name) == 0;
 363 }
 364
 365 static int spi_uevent(struct device *dev, struct kobj_uevent_env *env)
 366 {
 367         const struct spi_device         *spi = to_spi_device(dev);
 368         int rc;
 369
 370         rc = acpi_device_uevent_modalias(dev, env);
 371         if (rc != -ENODEV)
 372                 return rc;
 373
 374         return add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias);
 375 }
 376
 377 static int spi_probe(struct device *dev)
 378 {
 379         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
 380         struct spi_device               *spi = to_spi_device(dev);
 381         int ret;
 382
 383         ret = of_clk_set_defaults(dev->of_node, false);
 384         if (ret)
 385                 return ret;
 386
 387         if (dev->of_node) {
 388                 spi->irq = of_irq_get(dev->of_node, 0);
 389                 if (spi->irq == -EPROBE_DEFER)
 390                         return -EPROBE_DEFER;
 391                 if (spi->irq < 0)
 392                         spi->irq = 0;
 393         }
 394
 395         ret = dev_pm_domain_attach(dev, true);
 396         if (ret)
 397                 return ret;
 398
 399         if (sdrv->probe) {
 400                 ret = sdrv->probe(spi);
 401                 if (ret)
 402                         dev_pm_domain_detach(dev, true);
 403         }
 404
 405         return ret;
 406 }
 407
 408 static int spi_remove(struct device *dev)
 409 {
 410         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
 411
 412         if (sdrv->remove) {
 413                 int ret;
 414
 415                 ret = sdrv->remove(to_spi_device(dev));
 416                 if (ret)
 417                         dev_warn(dev,
 418                                  "Failed to unbind driver (%pe), ignoring\n",
 419                                  ERR_PTR(ret));
 420         }
 421
 422         dev_pm_domain_detach(dev, true);
 423
 424         return 0;
 425 }
 426
 427 static void spi_shutdown(struct device *dev)
 428 {
 429         if (dev->driver) {
 430                 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
 431
 432                 if (sdrv->shutdown)
 433                         sdrv->shutdown(to_spi_device(dev));
 434         }
 435 }
 436
 437 struct bus_type spi_bus_type = {
 438         .name           = "spi",
 439         .dev_groups     = spi_dev_groups,
 440         .match          = spi_match_device,
 441         .uevent         = spi_uevent,
 442         .probe          = spi_probe,
 443         .remove         = spi_remove,
 444         .shutdown       = spi_shutdown,
 445 };
 446 EXPORT_SYMBOL_GPL(spi_bus_type);
 447
 448 /**
 449  * __spi_register_driver - register a SPI driver
 450  * @owner: owner module of the driver to register
 451  * @sdrv: the driver to register
 452  * Context: can sleep
 453  *
 454  * Return: zero on success, else a negative error code.
 455  */
 456 int __spi_register_driver(struct module *owner, struct spi_driver *sdrv)
 457 {
 458         sdrv->driver.owner = owner;
 459         sdrv->driver.bus = &spi_bus_type;
 460         return driver_register(&sdrv->driver);
 461 }
 462 EXPORT_SYMBOL_GPL(__spi_register_driver);
 463
 464 /*-------------------------------------------------------------------------*/
 465
 466 /* SPI devices should normally not be created by SPI device drivers; that
 467  * would make them board-specific.  Similarly with SPI controller drivers.
 468  * Device registration normally goes into like arch/.../mach.../board-YYY.c
 469  * with other readonly (flashable) information about mainboard devices.
 470  */
 471
 472 struct boardinfo {
 473         struct list_head        list;
 474         struct spi_board_info   board_info;
 475 };
 476
 477 static LIST_HEAD(board_list);
 478 static LIST_HEAD(spi_controller_list);
 479
 480 /*
 481  * Used to protect add/del operation for board_info list and
 482  * spi_controller list, and their matching process
 483  * also used to protect object of type struct idr
 484  */
 485 static DEFINE_MUTEX(board_lock);
 486
 487 /*
 488  * Prevents addition of devices with same chip select and
 489  * addition of devices below an unregistering controller.
 490  */
 491 static DEFINE_MUTEX(spi_add_lock);
 492
 493 /**
 494  * spi_alloc_device - Allocate a new SPI device
 495  * @ctlr: Controller to which device is connected
 496  * Context: can sleep
 497  *
 498  * Allows a driver to allocate and initialize a spi_device without
 499  * registering it immediately.  This allows a driver to directly
 500  * fill the spi_device with device parameters before calling
 501  * spi_add_device() on it.
 502  *
 503  * Caller is responsible to call spi_add_device() on the returned
 504  * spi_device structure to add it to the SPI controller.  If the caller
 505  * needs to discard the spi_device without adding it, then it should
 506  * call spi_dev_put() on it.
 507  *
 508  * Return: a pointer to the new device, or NULL.
 509  */
 510 struct spi_device *spi_alloc_device(struct spi_controller *ctlr)
 511 {
 512         struct spi_device       *spi;
 513
 514         if (!spi_controller_get(ctlr))
 515                 return NULL;
 516
 517         spi = kzalloc(sizeof(*spi), GFP_KERNEL);
 518         if (!spi) {
 519                 spi_controller_put(ctlr);
 520                 return NULL;
 521         }
 522
 523         spi->master = spi->controller = ctlr;
 524         spi->dev.parent = &ctlr->dev;
 525         spi->dev.bus = &spi_bus_type;
 526         spi->dev.release = spidev_release;
 527         spi->cs_gpio = -ENOENT;
 528         spi->mode = ctlr->buswidth_override_bits;
 529
 530         spin_lock_init(&spi->statistics.lock);
 531
 532         device_initialize(&spi->dev);
 533         return spi;
 534 }
 535 EXPORT_SYMBOL_GPL(spi_alloc_device);
 536
 537 static void spi_dev_set_name(struct spi_device *spi)
 538 {
 539         struct acpi_device *adev = ACPI_COMPANION(&spi->dev);
 540
 541         if (adev) {
 542                 dev_set_name(&spi->dev, "spi-%s", acpi_dev_name(adev));
 543                 return;
 544         }
 545
 546         dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->controller->dev),
 547                      spi->chip_select);
 548 }
 549
 550 static int spi_dev_check(struct device *dev, void *data)
 551 {
 552         struct spi_device *spi = to_spi_device(dev);
 553         struct spi_device *new_spi = data;
 554
 555         if (spi->controller == new_spi->controller &&
 556             spi->chip_select == new_spi->chip_select)
 557                 return -EBUSY;
 558         return 0;
 559 }
 560
 561 /**
 562  * spi_add_device - Add spi_device allocated with spi_alloc_device
 563  * @spi: spi_device to register
 564  *
 565  * Companion function to spi_alloc_device.  Devices allocated with
 566  * spi_alloc_device can be added onto the spi bus with this function.
 567  *
 568  * Return: 0 on success; negative errno on failure
 569  */
 570 int spi_add_device(struct spi_device *spi)
 571 {
 572         struct spi_controller *ctlr = spi->controller;
 573         struct device *dev = ctlr->dev.parent;
 574         int status;
 575
 576         /* Chipselects are numbered 0..max; validate. */
 577         if (spi->chip_select >= ctlr->num_chipselect) {
 578                 dev_err(dev, "cs%d >= max %d\n", spi->chip_select,
 579                         ctlr->num_chipselect);
 580                 return -EINVAL;
 581         }
 582
 583         /* Set the bus ID string */
 584         spi_dev_set_name(spi);
 585
 586         /* We need to make sure there's no other device with this
 587          * chipselect **BEFORE** we call setup(), else we'll trash
 588          * its configuration.  Lock against concurrent add() calls.
 589          */
 590         mutex_lock(&spi_add_lock);
 591
 592         status = bus_for_each_dev(&spi_bus_type, NULL, spi, spi_dev_check);
 593         if (status) {
 594                 dev_err(dev, "chipselect %d already in use\n",
 595                                 spi->chip_select);
 596                 goto done;
 597         }
 598
 599         /* Controller may unregister concurrently */
 600         if (IS_ENABLED(CONFIG_SPI_DYNAMIC) &&
 601             !device_is_registered(&ctlr->dev)) {
 602                 status = -ENODEV;
 603                 goto done;
 604         }
 605
 606         /* Descriptors take precedence */
 607         if (ctlr->cs_gpiods)
 608                 spi->cs_gpiod = ctlr->cs_gpiods[spi->chip_select];
 609         else if (ctlr->cs_gpios)
 610                 spi->cs_gpio = ctlr->cs_gpios[spi->chip_select];
 611
 612         /* Drivers may modify this initial i/o setup, but will
 613          * normally rely on the device being setup.  Devices
 614          * using SPI_CS_HIGH can't coexist well otherwise...
 615          */
 616         status = spi_setup(spi);
 617         if (status < 0) {
 618                 dev_err(dev, "can't setup %s, status %d\n",
 619                                 dev_name(&spi->dev), status);
 620                 goto done;
 621         }
 622
 623         /* Device may be bound to an active driver when this returns */
 624         status = device_add(&spi->dev);
 625         if (status < 0)
 626                 dev_err(dev, "can't add %s, status %d\n",
 627                                 dev_name(&spi->dev), status);
 628         else
 629                 dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
 630
 631 done:
 632         mutex_unlock(&spi_add_lock);
 633         return status;
 634 }
 635 EXPORT_SYMBOL_GPL(spi_add_device);
 636
 637 /**
 638  * spi_new_device - instantiate one new SPI device
 639  * @ctlr: Controller to which device is connected
 640  * @chip: Describes the SPI device
 641  * Context: can sleep
 642  *
 643  * On typical mainboards, this is purely internal; and it's not needed
 644  * after board init creates the hard-wired devices.  Some development
 645  * platforms may not be able to use spi_register_board_info though, and
 646  * this is exported so that for example a USB or parport based adapter
 647  * driver could add devices (which it would learn about out-of-band).
 648  *
 649  * Return: the new device, or NULL.
 650  */
 651 struct spi_device *spi_new_device(struct spi_controller *ctlr,
 652                                   struct spi_board_info *chip)
 653 {
 654         struct spi_device       *proxy;
 655         int                     status;
 656
 657         /* NOTE:  caller did any chip->bus_num checks necessary.
 658          *
 659          * Also, unless we change the return value convention to use
 660          * error-or-pointer (not NULL-or-pointer), troubleshootability
 661          * suggests syslogged diagnostics are best here (ugh).
 662          */
 663
 664         proxy = spi_alloc_device(ctlr);
 665         if (!proxy)
 666                 return NULL;
 667
 668         WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
 669
 670         proxy->chip_select = chip->chip_select;
 671         proxy->max_speed_hz = chip->max_speed_hz;
 672         proxy->mode = chip->mode;
 673         proxy->irq = chip->irq;
 674         strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
 675         proxy->dev.platform_data = (void *) chip->platform_data;
 676         proxy->controller_data = chip->controller_data;
 677         proxy->controller_state = NULL;
 678
 679         if (chip->swnode) {
 680                 status = device_add_software_node(&proxy->dev, chip->swnode);
 681                 if (status) {
 682                         dev_err(&ctlr->dev, "failed to add software node to '%s': %d\n",
 683                                 chip->modalias, status);
 684                         goto err_dev_put;
 685                 }
 686         }
 687
 688         status = spi_add_device(proxy);
 689         if (status < 0)
 690                 goto err_dev_put;
 691
 692         return proxy;
 693
 694 err_dev_put:
 695         device_remove_software_node(&proxy->dev);
 696         spi_dev_put(proxy);
 697         return NULL;
 698 }
 699 EXPORT_SYMBOL_GPL(spi_new_device);
 700
 701 /**
 702  * spi_unregister_device - unregister a single SPI device
 703  * @spi: spi_device to unregister
 704  *
 705  * Start making the passed SPI device vanish. Normally this would be handled
 706  * by spi_unregister_controller().
 707  */
 708 void spi_unregister_device(struct spi_device *spi)
 709 {
 710         if (!spi)
 711                 return;
 712
 713         if (spi->dev.of_node) {
 714                 of_node_clear_flag(spi->dev.of_node, OF_POPULATED);
 715                 of_node_put(spi->dev.of_node);
 716         }
 717         if (ACPI_COMPANION(&spi->dev))
 718                 acpi_device_clear_enumerated(ACPI_COMPANION(&spi->dev));
 719         device_remove_software_node(&spi->dev);
 720         device_unregister(&spi->dev);
 721 }
 722 EXPORT_SYMBOL_GPL(spi_unregister_device);
 723
 724 static void spi_match_controller_to_boardinfo(struct spi_controller *ctlr,
 725                                               struct spi_board_info *bi)
 726 {
 727         struct spi_device *dev;
 728
 729         if (ctlr->bus_num != bi->bus_num)
 730                 return;
 731
 732         dev = spi_new_device(ctlr, bi);
 733         if (!dev)
 734                 dev_err(ctlr->dev.parent, "can't create new device for %s\n",
 735                         bi->modalias);
 736 }
 737
 738 /**
 739  * spi_register_board_info - register SPI devices for a given board
 740  * @info: array of chip descriptors
 741  * @n: how many descriptors are provided
 742  * Context: can sleep
 743  *
 744  * Board-specific early init code calls this (probably during arch_initcall)
 745  * with segments of the SPI device table.  Any device nodes are created later,
 746  * after the relevant parent SPI controller (bus_num) is defined.  We keep
 747  * this table of devices forever, so that reloading a controller driver will
 748  * not make Linux forget about these hard-wired devices.
 749  *
 750  * Other code can also call this, e.g. a particular add-on board might provide
 751  * SPI devices through its expansion connector, so code initializing that board
 752  * would naturally declare its SPI devices.
 753  *
 754  * The board info passed can safely be __initdata ... but be careful of
 755  * any embedded pointers (platform_data, etc), they're copied as-is.
 756  *
 757  * Return: zero on success, else a negative error code.
 758  */
 759 int spi_register_board_info(struct spi_board_info const *info, unsigned n)
 760 {
 761         struct boardinfo *bi;
 762         int i;
 763
 764         if (!n)
 765                 return 0;
 766
 767         bi = kcalloc(n, sizeof(*bi), GFP_KERNEL);
 768         if (!bi)
 769                 return -ENOMEM;
 770
 771         for (i = 0; i < n; i++, bi++, info++) {
 772                 struct spi_controller *ctlr;
 773
 774                 memcpy(&bi->board_info, info, sizeof(*info));
 775
 776                 mutex_lock(&board_lock);
 777                 list_add_tail(&bi->list, &board_list);
 778                 list_for_each_entry(ctlr, &spi_controller_list, list)
 779                         spi_match_controller_to_boardinfo(ctlr,
 780                                                           &bi->board_info);
 781                 mutex_unlock(&board_lock);
 782         }
 783
 784         return 0;
 785 }
 786
 787 /*-------------------------------------------------------------------------*/
 788
 789 static void spi_set_cs(struct spi_device *spi, bool enable, bool force)
 790 {
 791         bool activate = enable;
 792
 793         /*
 794          * Avoid calling into the driver (or doing delays) if the chip select
 795          * isn't actually changing from the last time this was called.
 796          */
 797         if (!force && (spi->controller->last_cs_enable == enable) &&
 798             (spi->controller->last_cs_mode_high == (spi->mode & SPI_CS_HIGH)))
 799                 return;
 800
 801         spi->controller->last_cs_enable = enable;
 802         spi->controller->last_cs_mode_high = spi->mode & SPI_CS_HIGH;
 803
 804         if (spi->cs_gpiod || gpio_is_valid(spi->cs_gpio) ||
 805             !spi->controller->set_cs_timing) {
 806                 if (activate)
 807                         spi_delay_exec(&spi->controller->cs_setup, NULL);
 808                 else
 809                         spi_delay_exec(&spi->controller->cs_hold, NULL);
 810         }
 811
 812         if (spi->mode & SPI_CS_HIGH)
 813                 enable = !enable;
 814
 815         if (spi->cs_gpiod || gpio_is_valid(spi->cs_gpio)) {
 816                 if (!(spi->mode & SPI_NO_CS)) {
 817                         if (spi->cs_gpiod)
 818                                 /* polarity handled by gpiolib */
 819                                 gpiod_set_value_cansleep(spi->cs_gpiod, activate);
 820                         else
 821                                 /*
 822                                  * invert the enable line, as active low is
 823                                  * default for SPI.
 824                                  */
 825                                 gpio_set_value_cansleep(spi->cs_gpio, !enable);
 826                 }
 827                 /* Some SPI masters need both GPIO CS & slave_select */
 828                 if ((spi->controller->flags & SPI_MASTER_GPIO_SS) &&
 829                     spi->controller->set_cs)
 830                         spi->controller->set_cs(spi, !enable);
 831         } else if (spi->controller->set_cs) {
 832                 spi->controller->set_cs(spi, !enable);
 833         }
 834
 835         if (spi->cs_gpiod || gpio_is_valid(spi->cs_gpio) ||
 836             !spi->controller->set_cs_timing) {
 837                 if (!activate)
 838                         spi_delay_exec(&spi->controller->cs_inactive, NULL);
 839         }
 840 }
 841
 842 #ifdef CONFIG_HAS_DMA
 843 int spi_map_buf(struct spi_controller *ctlr, struct device *dev,
 844                 struct sg_table *sgt, void *buf, size_t len,
 845                 enum dma_data_direction dir)
 846 {
 847         const bool vmalloced_buf = is_vmalloc_addr(buf);
 848         unsigned int max_seg_size = dma_get_max_seg_size(dev);
 849 #ifdef CONFIG_HIGHMEM
 850         const bool kmap_buf = ((unsigned long)buf >= PKMAP_BASE &&
 851                                 (unsigned long)buf < (PKMAP_BASE +
 852                                         (LAST_PKMAP * PAGE_SIZE)));
 853 #else
 854         const bool kmap_buf = false;
 855 #endif
 856         int desc_len;
 857         int sgs;
 858         struct page *vm_page;
 859         struct scatterlist *sg;
 860         void *sg_buf;
 861         size_t min;
 862         int i, ret;
 863
 864         if (vmalloced_buf || kmap_buf) {
 865                 desc_len = min_t(int, max_seg_size, PAGE_SIZE);
 866                 sgs = DIV_ROUND_UP(len + offset_in_page(buf), desc_len);
 867         } else if (virt_addr_valid(buf)) {
 868                 desc_len = min_t(int, max_seg_size, ctlr->max_dma_len);
 869                 sgs = DIV_ROUND_UP(len, desc_len);
 870         } else {
 871                 return -EINVAL;
 872         }
 873
 874         ret = sg_alloc_table(sgt, sgs, GFP_KERNEL);
 875         if (ret != 0)
 876                 return ret;
 877
 878         sg = &sgt->sgl[0];
 879         for (i = 0; i < sgs; i++) {
 880
 881                 if (vmalloced_buf || kmap_buf) {
 882                         /*
 883                          * Next scatterlist entry size is the minimum between
 884                          * the desc_len and the remaining buffer length that
 885                          * fits in a page.
 886                          */
 887                         min = min_t(size_t, desc_len,
 888                                     min_t(size_t, len,
 889                                           PAGE_SIZE - offset_in_page(buf)));
 890                         if (vmalloced_buf)
 891                                 vm_page = vmalloc_to_page(buf);
 892                         else
 893                                 vm_page = kmap_to_page(buf);
 894                         if (!vm_page) {
 895                                 sg_free_table(sgt);
 896                                 return -ENOMEM;
 897                         }
 898                         sg_set_page(sg, vm_page,
 899                                     min, offset_in_page(buf));
 900                 } else {
 901                         min = min_t(size_t, len, desc_len);
 902                         sg_buf = buf;
 903                         sg_set_buf(sg, sg_buf, min);
 904                 }
 905
 906                 buf += min;
 907                 len -= min;
 908                 sg = sg_next(sg);
 909         }
 910
 911         ret = dma_map_sg(dev, sgt->sgl, sgt->nents, dir);
 912         if (!ret)
 913                 ret = -ENOMEM;
 914         if (ret < 0) {
 915                 sg_free_table(sgt);
 916                 return ret;
 917         }
 918
 919         sgt->nents = ret;
 920
 921         return 0;
 922 }
 923
 924 void spi_unmap_buf(struct spi_controller *ctlr, struct device *dev,
 925                    struct sg_table *sgt, enum dma_data_direction dir)
 926 {
 927         if (sgt->orig_nents) {
 928                 dma_unmap_sg(dev, sgt->sgl, sgt->orig_nents, dir);
 929                 sg_free_table(sgt);
 930         }
 931 }
 932
 933 static int __spi_map_msg(struct spi_controller *ctlr, struct spi_message *msg)
 934 {
 935         struct device *tx_dev, *rx_dev;
 936         struct spi_transfer *xfer;
 937         int ret;
 938
 939         if (!ctlr->can_dma)
 940                 return 0;
 941
 942         if (ctlr->dma_tx)
 943                 tx_dev = ctlr->dma_tx->device->dev;
 944         else
 945                 tx_dev = ctlr->dev.parent;
 946
 947         if (ctlr->dma_rx)
 948                 rx_dev = ctlr->dma_rx->device->dev;
 949         else
 950                 rx_dev = ctlr->dev.parent;
 951
 952         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 953                 if (!ctlr->can_dma(ctlr, msg->spi, xfer))
 954                         continue;
 955
 956                 if (xfer->tx_buf != NULL) {
 957                         ret = spi_map_buf(ctlr, tx_dev, &xfer->tx_sg,
 958                                           (void *)xfer->tx_buf, xfer->len,
 959                                           DMA_TO_DEVICE);
 960                         if (ret != 0)
 961                                 return ret;
 962                 }
 963
 964                 if (xfer->rx_buf != NULL) {
 965                         ret = spi_map_buf(ctlr, rx_dev, &xfer->rx_sg,
 966                                           xfer->rx_buf, xfer->len,
 967                                           DMA_FROM_DEVICE);
 968                         if (ret != 0) {
 969                                 spi_unmap_buf(ctlr, tx_dev, &xfer->tx_sg,
 970                                               DMA_TO_DEVICE);
 971                                 return ret;
 972                         }
 973                 }
 974         }
 975
 976         ctlr->cur_msg_mapped = true;
 977
 978         return 0;
 979 }
 980
 981 static int __spi_unmap_msg(struct spi_controller *ctlr, struct spi_message *msg)
 982 {
 983         struct spi_transfer *xfer;
 984         struct device *tx_dev, *rx_dev;
 985
 986         if (!ctlr->cur_msg_mapped || !ctlr->can_dma)
 987                 return 0;
 988
 989         if (ctlr->dma_tx)
 990                 tx_dev = ctlr->dma_tx->device->dev;
 991         else
 992                 tx_dev = ctlr->dev.parent;
 993
 994         if (ctlr->dma_rx)
 995                 rx_dev = ctlr->dma_rx->device->dev;
 996         else
 997                 rx_dev = ctlr->dev.parent;
 998
 999         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1000                 if (!ctlr->can_dma(ctlr, msg->spi, xfer))
1001                         continue;
1002
1003                 spi_unmap_buf(ctlr, rx_dev, &xfer->rx_sg, DMA_FROM_DEVICE);
1004                 spi_unmap_buf(ctlr, tx_dev, &xfer->tx_sg, DMA_TO_DEVICE);
1005         }
1006
1007         ctlr->cur_msg_mapped = false;
1008
1009         return 0;
1010 }
1011 #else /* !CONFIG_HAS_DMA */
1012 static inline int __spi_map_msg(struct spi_controller *ctlr,
1013                                 struct spi_message *msg)
1014 {
1015         return 0;
1016 }
1017
1018 static inline int __spi_unmap_msg(struct spi_controller *ctlr,
1019                                   struct spi_message *msg)
1020 {
1021         return 0;
1022 }
1023 #endif /* !CONFIG_HAS_DMA */
1024
1025 static inline int spi_unmap_msg(struct spi_controller *ctlr,
1026                                 struct spi_message *msg)
1027 {
1028         struct spi_transfer *xfer;
1029
1030         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1031                 /*
1032                  * Restore the original value of tx_buf or rx_buf if they are
1033                  * NULL.
1034                  */
1035                 if (xfer->tx_buf == ctlr->dummy_tx)
1036                         xfer->tx_buf = NULL;
1037                 if (xfer->rx_buf == ctlr->dummy_rx)
1038                         xfer->rx_buf = NULL;
1039         }
1040
1041         return __spi_unmap_msg(ctlr, msg);
1042 }
1043
1044 static int spi_map_msg(struct spi_controller *ctlr, struct spi_message *msg)
1045 {
1046         struct spi_transfer *xfer;
1047         void *tmp;
1048         unsigned int max_tx, max_rx;
1049
1050         if ((ctlr->flags & (SPI_CONTROLLER_MUST_RX | SPI_CONTROLLER_MUST_TX))
1051                 && !(msg->spi->mode & SPI_3WIRE)) {
1052                 max_tx = 0;
1053                 max_rx = 0;
1054
1055                 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1056                         if ((ctlr->flags & SPI_CONTROLLER_MUST_TX) &&
1057                             !xfer->tx_buf)
1058                                 max_tx = max(xfer->len, max_tx);
1059                         if ((ctlr->flags & SPI_CONTROLLER_MUST_RX) &&
1060                             !xfer->rx_buf)
1061                                 max_rx = max(xfer->len, max_rx);
1062                 }
1063
1064                 if (max_tx) {
1065                         tmp = krealloc(ctlr->dummy_tx, max_tx,
1066                                        GFP_KERNEL | GFP_DMA);
1067                         if (!tmp)
1068                                 return -ENOMEM;
1069                         ctlr->dummy_tx = tmp;
1070                         memset(tmp, 0, max_tx);
1071                 }
1072
1073                 if (max_rx) {
1074                         tmp = krealloc(ctlr->dummy_rx, max_rx,
1075                                        GFP_KERNEL | GFP_DMA);
1076                         if (!tmp)
1077                                 return -ENOMEM;
1078                         ctlr->dummy_rx = tmp;
1079                 }
1080
1081                 if (max_tx || max_rx) {
1082                         list_for_each_entry(xfer, &msg->transfers,
1083                                             transfer_list) {
1084                                 if (!xfer->len)
1085                                         continue;
1086                                 if (!xfer->tx_buf)
1087                                         xfer->tx_buf = ctlr->dummy_tx;
1088                                 if (!xfer->rx_buf)
1089                                         xfer->rx_buf = ctlr->dummy_rx;
1090                         }
1091                 }
1092         }
1093
1094         return __spi_map_msg(ctlr, msg);
1095 }
1096
1097 static int spi_transfer_wait(struct spi_controller *ctlr,
1098                              struct spi_message *msg,
1099                              struct spi_transfer *xfer)
1100 {
1101         struct spi_statistics *statm = &ctlr->statistics;
1102         struct spi_statistics *stats = &msg->spi->statistics;
1103         u32 speed_hz = xfer->speed_hz;
1104         unsigned long long ms;
1105
1106         if (spi_controller_is_slave(ctlr)) {
1107                 if (wait_for_completion_interruptible(&ctlr->xfer_completion)) {
1108                         dev_dbg(&msg->spi->dev, "SPI transfer interrupted\n");
1109                         return -EINTR;
1110                 }
1111         } else {
1112                 if (!speed_hz)
1113                         speed_hz = 100000;
1114
1115                 ms = 8LL * 1000LL * xfer->len;
1116                 do_div(ms, speed_hz);
1117                 ms += ms + 200; /* some tolerance */
1118
1119                 if (ms > UINT_MAX)
1120                         ms = UINT_MAX;
1121
1122                 ms = wait_for_completion_timeout(&ctlr->xfer_completion,
1123                                                  msecs_to_jiffies(ms));
1124
1125                 if (ms == 0) {
1126                         SPI_STATISTICS_INCREMENT_FIELD(statm, timedout);
1127                         SPI_STATISTICS_INCREMENT_FIELD(stats, timedout);
1128                         dev_err(&msg->spi->dev,
1129                                 "SPI transfer timed out\n");
1130                         return -ETIMEDOUT;
1131                 }
1132         }
1133
1134         return 0;
1135 }
1136
1137 static void _spi_transfer_delay_ns(u32 ns)
1138 {
1139         if (!ns)
1140                 return;
1141         if (ns <= 1000) {
1142                 ndelay(ns);
1143         } else {
1144                 u32 us = DIV_ROUND_UP(ns, 1000);
1145
1146                 if (us <= 10)
1147                         udelay(us);
1148                 else
1149                         usleep_range(us, us + DIV_ROUND_UP(us, 10));
1150         }
1151 }
1152
1153 int spi_delay_to_ns(struct spi_delay *_delay, struct spi_transfer *xfer)
1154 {
1155         u32 delay = _delay->value;
1156         u32 unit = _delay->unit;
1157         u32 hz;
1158
1159         if (!delay)
1160                 return 0;
1161
1162         switch (unit) {
1163         case SPI_DELAY_UNIT_USECS:
1164                 delay *= 1000;
1165                 break;
1166         case SPI_DELAY_UNIT_NSECS: /* nothing to do here */
1167                 break;
1168         case SPI_DELAY_UNIT_SCK:
1169                 /* clock cycles need to be obtained from spi_transfer */
1170                 if (!xfer)
1171                         return -EINVAL;
1172                 /* if there is no effective speed know, then approximate
1173                  * by underestimating with half the requested hz
1174                  */
1175                 hz = xfer->effective_speed_hz ?: xfer->speed_hz / 2;
1176                 if (!hz)
1177                         return -EINVAL;
1178                 delay *= DIV_ROUND_UP(1000000000, hz);
1179                 break;
1180         default:
1181                 return -EINVAL;
1182         }
1183
1184         return delay;
1185 }
1186 EXPORT_SYMBOL_GPL(spi_delay_to_ns);
1187
1188 int spi_delay_exec(struct spi_delay *_delay, struct spi_transfer *xfer)
1189 {
1190         int delay;
1191
1192         might_sleep();
1193
1194         if (!_delay)
1195                 return -EINVAL;
1196
1197         delay = spi_delay_to_ns(_delay, xfer);
1198         if (delay < 0)
1199                 return delay;
1200
1201         _spi_transfer_delay_ns(delay);
1202
1203         return 0;
1204 }
1205 EXPORT_SYMBOL_GPL(spi_delay_exec);
1206
1207 static void _spi_transfer_cs_change_delay(struct spi_message *msg,
1208                                           struct spi_transfer *xfer)
1209 {
1210         u32 delay = xfer->cs_change_delay.value;
1211         u32 unit = xfer->cs_change_delay.unit;
1212         int ret;
1213
1214         /* return early on "fast" mode - for everything but USECS */
1215         if (!delay) {
1216                 if (unit == SPI_DELAY_UNIT_USECS)
1217                         _spi_transfer_delay_ns(10000);
1218                 return;
1219         }
1220
1221         ret = spi_delay_exec(&xfer->cs_change_delay, xfer);
1222         if (ret) {
1223                 dev_err_once(&msg->spi->dev,
1224                              "Use of unsupported delay unit %i, using default of 10us\n",
1225                              unit);
1226                 _spi_transfer_delay_ns(10000);
1227         }
1228 }
1229
1230 /*
1231  * spi_transfer_one_message - Default implementation of transfer_one_message()
1232  *
1233  * This is a standard implementation of transfer_one_message() for
1234  * drivers which implement a transfer_one() operation.  It provides
1235  * standard handling of delays and chip select management.
1236  */
1237 static int spi_transfer_one_message(struct spi_controller *ctlr,
1238                                     struct spi_message *msg)
1239 {
1240         struct spi_transfer *xfer;
1241         bool keep_cs = false;
1242         int ret = 0;
1243         struct spi_statistics *statm = &ctlr->statistics;
1244         struct spi_statistics *stats = &msg->spi->statistics;
1245
1246         spi_set_cs(msg->spi, true, false);
1247
1248         SPI_STATISTICS_INCREMENT_FIELD(statm, messages);
1249         SPI_STATISTICS_INCREMENT_FIELD(stats, messages);
1250
1251         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1252                 trace_spi_transfer_start(msg, xfer);
1253
1254                 spi_statistics_add_transfer_stats(statm, xfer, ctlr);
1255                 spi_statistics_add_transfer_stats(stats, xfer, ctlr);
1256
1257                 if (!ctlr->ptp_sts_supported) {
1258                         xfer->ptp_sts_word_pre = 0;
1259                         ptp_read_system_prets(xfer->ptp_sts);
1260                 }
1261
1262                 if ((xfer->tx_buf || xfer->rx_buf) && xfer->len) {
1263                         reinit_completion(&ctlr->xfer_completion);
1264
1265 fallback_pio:
1266                         ret = ctlr->transfer_one(ctlr, msg->spi, xfer);
1267                         if (ret < 0) {
1268                                 if (ctlr->cur_msg_mapped &&
1269                                    (xfer->error & SPI_TRANS_FAIL_NO_START)) {
1270                                         __spi_unmap_msg(ctlr, msg);
1271                                         ctlr->fallback = true;
1272                                         xfer->error &= ~SPI_TRANS_FAIL_NO_START;
1273                                         goto fallback_pio;
1274                                 }
1275
1276                                 SPI_STATISTICS_INCREMENT_FIELD(statm,
1277                                                                errors);
1278                                 SPI_STATISTICS_INCREMENT_FIELD(stats,
1279                                                                errors);
1280                                 dev_err(&msg->spi->dev,
1281                                         "SPI transfer failed: %d\n", ret);
1282                                 goto out;
1283                         }
1284
1285                         if (ret > 0) {
1286                                 ret = spi_transfer_wait(ctlr, msg, xfer);
1287                                 if (ret < 0)
1288                                         msg->status = ret;
1289                         }
1290                 } else {
1291                         if (xfer->len)
1292                                 dev_err(&msg->spi->dev,
1293                                         "Bufferless transfer has length %u\n",
1294                                         xfer->len);
1295                 }
1296
1297                 if (!ctlr->ptp_sts_supported) {
1298                         ptp_read_system_postts(xfer->ptp_sts);
1299                         xfer->ptp_sts_word_post = xfer->len;
1300                 }
1301
1302                 trace_spi_transfer_stop(msg, xfer);
1303
1304                 if (msg->status != -EINPROGRESS)
1305                         goto out;
1306
1307                 spi_transfer_delay_exec(xfer);
1308
1309                 if (xfer->cs_change) {
1310                         if (list_is_last(&xfer->transfer_list,
1311                                          &msg->transfers)) {
1312                                 keep_cs = true;
1313                         } else {
1314                                 spi_set_cs(msg->spi, false, false);
1315                                 _spi_transfer_cs_change_delay(msg, xfer);
1316                                 spi_set_cs(msg->spi, true, false);
1317                         }
1318                 }
1319
1320                 msg->actual_length += xfer->len;
1321         }
1322
1323 out:
1324         if (ret != 0 || !keep_cs)
1325                 spi_set_cs(msg->spi, false, false);
1326
1327         if (msg->status == -EINPROGRESS)
1328                 msg->status = ret;
1329
1330         if (msg->status && ctlr->handle_err)
1331                 ctlr->handle_err(ctlr, msg);
1332
1333         spi_finalize_current_message(ctlr);
1334
1335         return ret;
1336 }
1337
1338 /**
1339  * spi_finalize_current_transfer - report completion of a transfer
1340  * @ctlr: the controller reporting completion
1341  *
1342  * Called by SPI drivers using the core transfer_one_message()
1343  * implementation to notify it that the current interrupt driven
1344  * transfer has finished and the next one may be scheduled.
1345  */
1346 void spi_finalize_current_transfer(struct spi_controller *ctlr)
1347 {
1348         complete(&ctlr->xfer_completion);
1349 }
1350 EXPORT_SYMBOL_GPL(spi_finalize_current_transfer);
1351
1352 static void spi_idle_runtime_pm(struct spi_controller *ctlr)
1353 {
1354         if (ctlr->auto_runtime_pm) {
1355                 pm_runtime_mark_last_busy(ctlr->dev.parent);
1356                 pm_runtime_put_autosuspend(ctlr->dev.parent);
1357         }
1358 }
1359
1360 /**
1361  * __spi_pump_messages - function which processes spi message queue
1362  * @ctlr: controller to process queue for
1363  * @in_kthread: true if we are in the context of the message pump thread
1364  *
1365  * This function checks if there is any spi message in the queue that
1366  * needs processing and if so call out to the driver to initialize hardware
1367  * and transfer each message.
1368  *
1369  * Note that it is called both from the kthread itself and also from
1370  * inside spi_sync(); the queue extraction handling at the top of the
1371  * function should deal with this safely.
1372  */
1373 static void __spi_pump_messages(struct spi_controller *ctlr, bool in_kthread)
1374 {
1375         struct spi_transfer *xfer;
1376         struct spi_message *msg;
1377         bool was_busy = false;
1378         unsigned long flags;
1379         int ret;
1380
1381         /* Lock queue */
1382         spin_lock_irqsave(&ctlr->queue_lock, flags);
1383
1384         /* Make sure we are not already running a message */
1385         if (ctlr->cur_msg) {
1386                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1387                 return;
1388         }
1389
1390         /* If another context is idling the device then defer */
1391         if (ctlr->idling) {
1392                 kthread_queue_work(ctlr->kworker, &ctlr->pump_messages);
1393                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1394                 return;
1395         }
1396
1397         /* Check if the queue is idle */
1398         if (list_empty(&ctlr->queue) || !ctlr->running) {
1399                 if (!ctlr->busy) {
1400                         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1401                         return;
1402                 }
1403
1404                 /* Defer any non-atomic teardown to the thread */
1405                 if (!in_kthread) {
1406                         if (!ctlr->dummy_rx && !ctlr->dummy_tx &&
1407                             !ctlr->unprepare_transfer_hardware) {
1408                                 spi_idle_runtime_pm(ctlr);
1409                                 ctlr->busy = false;
1410                                 trace_spi_controller_idle(ctlr);
1411                         } else {
1412                                 kthread_queue_work(ctlr->kworker,
1413                                                    &ctlr->pump_messages);
1414                         }
1415                         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1416                         return;
1417                 }
1418
1419                 ctlr->busy = false;
1420                 ctlr->idling = true;
1421                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1422
1423                 kfree(ctlr->dummy_rx);
1424                 ctlr->dummy_rx = NULL;
1425                 kfree(ctlr->dummy_tx);
1426                 ctlr->dummy_tx = NULL;
1427                 if (ctlr->unprepare_transfer_hardware &&
1428                     ctlr->unprepare_transfer_hardware(ctlr))
1429                         dev_err(&ctlr->dev,
1430                                 "failed to unprepare transfer hardware\n");
1431                 spi_idle_runtime_pm(ctlr);
1432                 trace_spi_controller_idle(ctlr);
1433
1434                 spin_lock_irqsave(&ctlr->queue_lock, flags);
1435                 ctlr->idling = false;
1436                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1437                 return;
1438         }
1439
1440         /* Extract head of queue */
1441         msg = list_first_entry(&ctlr->queue, struct spi_message, queue);
1442         ctlr->cur_msg = msg;
1443
1444         list_del_init(&msg->queue);
1445         if (ctlr->busy)
1446                 was_busy = true;
1447         else
1448                 ctlr->busy = true;
1449         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1450
1451         mutex_lock(&ctlr->io_mutex);
1452
1453         if (!was_busy && ctlr->auto_runtime_pm) {
1454                 ret = pm_runtime_get_sync(ctlr->dev.parent);
1455                 if (ret < 0) {
1456                         pm_runtime_put_noidle(ctlr->dev.parent);
1457                         dev_err(&ctlr->dev, "Failed to power device: %d\n",
1458                                 ret);
1459                         mutex_unlock(&ctlr->io_mutex);
1460                         return;
1461                 }
1462         }
1463
1464         if (!was_busy)
1465                 trace_spi_controller_busy(ctlr);
1466
1467         if (!was_busy && ctlr->prepare_transfer_hardware) {
1468                 ret = ctlr->prepare_transfer_hardware(ctlr);
1469                 if (ret) {
1470                         dev_err(&ctlr->dev,
1471                                 "failed to prepare transfer hardware: %d\n",
1472                                 ret);
1473
1474                         if (ctlr->auto_runtime_pm)
1475                                 pm_runtime_put(ctlr->dev.parent);
1476
1477                         msg->status = ret;
1478                         spi_finalize_current_message(ctlr);
1479
1480                         mutex_unlock(&ctlr->io_mutex);
1481                         return;
1482                 }
1483         }
1484
1485         trace_spi_message_start(msg);
1486
1487         if (ctlr->prepare_message) {
1488                 ret = ctlr->prepare_message(ctlr, msg);
1489                 if (ret) {
1490                         dev_err(&ctlr->dev, "failed to prepare message: %d\n",
1491                                 ret);
1492                         msg->status = ret;
1493                         spi_finalize_current_message(ctlr);
1494                         goto out;
1495                 }
1496                 ctlr->cur_msg_prepared = true;
1497         }
1498
1499         ret = spi_map_msg(ctlr, msg);
1500         if (ret) {
1501                 msg->status = ret;
1502                 spi_finalize_current_message(ctlr);
1503                 goto out;
1504         }
1505
1506         if (!ctlr->ptp_sts_supported && !ctlr->transfer_one) {
1507                 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1508                         xfer->ptp_sts_word_pre = 0;
1509                         ptp_read_system_prets(xfer->ptp_sts);
1510                 }
1511         }
1512
1513         ret = ctlr->transfer_one_message(ctlr, msg);
1514         if (ret) {
1515                 dev_err(&ctlr->dev,
1516                         "failed to transfer one message from queue\n");
1517                 goto out;
1518         }
1519
1520 out:
1521         mutex_unlock(&ctlr->io_mutex);
1522
1523         /* Prod the scheduler in case transfer_one() was busy waiting */
1524         if (!ret)
1525                 cond_resched();
1526 }
1527
1528 /**
1529  * spi_pump_messages - kthread work function which processes spi message queue
1530  * @work: pointer to kthread work struct contained in the controller struct
1531  */
1532 static void spi_pump_messages(struct kthread_work *work)
1533 {
1534         struct spi_controller *ctlr =
1535                 container_of(work, struct spi_controller, pump_messages);
1536
1537         __spi_pump_messages(ctlr, true);
1538 }
1539
1540 /**
1541  * spi_take_timestamp_pre - helper for drivers to collect the beginning of the
1542  *                          TX timestamp for the requested byte from the SPI
1543  *                          transfer. The frequency with which this function
1544  *                          must be called (once per word, once for the whole
1545  *                          transfer, once per batch of words etc) is arbitrary
1546  *                          as long as the @tx buffer offset is greater than or
1547  *                          equal to the requested byte at the time of the
1548  *                          call. The timestamp is only taken once, at the
1549  *                          first such call. It is assumed that the driver
1550  *                          advances its @tx buffer pointer monotonically.
1551  * @ctlr: Pointer to the spi_controller structure of the driver
1552  * @xfer: Pointer to the transfer being timestamped
1553  * @progress: How many words (not bytes) have been transferred so far
1554  * @irqs_off: If true, will disable IRQs and preemption for the duration of the
1555  *            transfer, for less jitter in time measurement. Only compatible
1556  *            with PIO drivers. If true, must follow up with
1557  *            spi_take_timestamp_post or otherwise system will crash.
1558  *            WARNING: for fully predictable results, the CPU frequency must
1559  *            also be under control (governor).
1560  */
1561 void spi_take_timestamp_pre(struct spi_controller *ctlr,
1562                             struct spi_transfer *xfer,
1563                             size_t progress, bool irqs_off)
1564 {
1565         if (!xfer->ptp_sts)
1566                 return;
1567
1568         if (xfer->timestamped)
1569                 return;
1570
1571         if (progress > xfer->ptp_sts_word_pre)
1572                 return;
1573
1574         /* Capture the resolution of the timestamp */
1575         xfer->ptp_sts_word_pre = progress;
1576
1577         if (irqs_off) {
1578                 local_irq_save(ctlr->irq_flags);
1579                 preempt_disable();
1580         }
1581
1582         ptp_read_system_prets(xfer->ptp_sts);
1583 }
1584 EXPORT_SYMBOL_GPL(spi_take_timestamp_pre);
1585
1586 /**
1587  * spi_take_timestamp_post - helper for drivers to collect the end of the
1588  *                           TX timestamp for the requested byte from the SPI
1589  *                           transfer. Can be called with an arbitrary
1590  *                           frequency: only the first call where @tx exceeds
1591  *                           or is equal to the requested word will be
1592  *                           timestamped.
1593  * @ctlr: Pointer to the spi_controller structure of the driver
1594  * @xfer: Pointer to the transfer being timestamped
1595  * @progress: How many words (not bytes) have been transferred so far
1596  * @irqs_off: If true, will re-enable IRQs and preemption for the local CPU.
1597  */
1598 void spi_take_timestamp_post(struct spi_controller *ctlr,
1599                              struct spi_transfer *xfer,
1600                              size_t progress, bool irqs_off)
1601 {
1602         if (!xfer->ptp_sts)
1603                 return;
1604
1605         if (xfer->timestamped)
1606                 return;
1607
1608         if (progress < xfer->ptp_sts_word_post)
1609                 return;
1610
1611         ptp_read_system_postts(xfer->ptp_sts);
1612
1613         if (irqs_off) {
1614                 local_irq_restore(ctlr->irq_flags);
1615                 preempt_enable();
1616         }
1617
1618         /* Capture the resolution of the timestamp */
1619         xfer->ptp_sts_word_post = progress;
1620
1621         xfer->timestamped = true;
1622 }
1623 EXPORT_SYMBOL_GPL(spi_take_timestamp_post);
1624
1625 /**
1626  * spi_set_thread_rt - set the controller to pump at realtime priority
1627  * @ctlr: controller to boost priority of
1628  *
1629  * This can be called because the controller requested realtime priority
1630  * (by setting the ->rt value before calling spi_register_controller()) or
1631  * because a device on the bus said that its transfers needed realtime
1632  * priority.
1633  *
1634  * NOTE: at the moment if any device on a bus says it needs realtime then
1635  * the thread will be at realtime priority for all transfers on that
1636  * controller.  If this eventually becomes a problem we may see if we can
1637  * find a way to boost the priority only temporarily during relevant
1638  * transfers.
1639  */
1640 static void spi_set_thread_rt(struct spi_controller *ctlr)
1641 {
1642         dev_info(&ctlr->dev,
1643                 "will run message pump with realtime priority\n");
1644         sched_set_fifo(ctlr->kworker->task);
1645 }
1646
1647 static int spi_init_queue(struct spi_controller *ctlr)
1648 {
1649         ctlr->running = false;
1650         ctlr->busy = false;
1651
1652         ctlr->kworker = kthread_create_worker(0, dev_name(&ctlr->dev));
1653         if (IS_ERR(ctlr->kworker)) {
1654                 dev_err(&ctlr->dev, "failed to create message pump kworker\n");
1655                 return PTR_ERR(ctlr->kworker);
1656         }
1657
1658         kthread_init_work(&ctlr->pump_messages, spi_pump_messages);
1659
1660         /*
1661          * Controller config will indicate if this controller should run the
1662          * message pump with high (realtime) priority to reduce the transfer
1663          * latency on the bus by minimising the delay between a transfer
1664          * request and the scheduling of the message pump thread. Without this
1665          * setting the message pump thread will remain at default priority.
1666          */
1667         if (ctlr->rt)
1668                 spi_set_thread_rt(ctlr);
1669
1670         return 0;
1671 }
1672
1673 /**
1674  * spi_get_next_queued_message() - called by driver to check for queued
1675  * messages
1676  * @ctlr: the controller to check for queued messages
1677  *
1678  * If there are more messages in the queue, the next message is returned from
1679  * this call.
1680  *
1681  * Return: the next message in the queue, else NULL if the queue is empty.
1682  */
1683 struct spi_message *spi_get_next_queued_message(struct spi_controller *ctlr)
1684 {
1685         struct spi_message *next;
1686         unsigned long flags;
1687
1688         /* get a pointer to the next message, if any */
1689         spin_lock_irqsave(&ctlr->queue_lock, flags);
1690         next = list_first_entry_or_null(&ctlr->queue, struct spi_message,
1691                                         queue);
1692         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1693
1694         return next;
1695 }
1696 EXPORT_SYMBOL_GPL(spi_get_next_queued_message);
1697
1698 /**
1699  * spi_finalize_current_message() - the current message is complete
1700  * @ctlr: the controller to return the message to
1701  *
1702  * Called by the driver to notify the core that the message in the front of the
1703  * queue is complete and can be removed from the queue.
1704  */
1705 void spi_finalize_current_message(struct spi_controller *ctlr)
1706 {
1707         struct spi_transfer *xfer;
1708         struct spi_message *mesg;
1709         unsigned long flags;
1710         int ret;
1711
1712         spin_lock_irqsave(&ctlr->queue_lock, flags);
1713         mesg = ctlr->cur_msg;
1714         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1715
1716         if (!ctlr->ptp_sts_supported && !ctlr->transfer_one) {
1717                 list_for_each_entry(xfer, &mesg->transfers, transfer_list) {
1718                         ptp_read_system_postts(xfer->ptp_sts);
1719                         xfer->ptp_sts_word_post = xfer->len;
1720                 }
1721         }
1722
1723         if (unlikely(ctlr->ptp_sts_supported))
1724                 list_for_each_entry(xfer, &mesg->transfers, transfer_list)
1725                         WARN_ON_ONCE(xfer->ptp_sts && !xfer->timestamped);
1726
1727         spi_unmap_msg(ctlr, mesg);
1728
1729         /* In the prepare_messages callback the spi bus has the opportunity to
1730          * split a transfer to smaller chunks.
1731          * Release splited transfers here since spi_map_msg is done on the
1732          * splited transfers.
1733          */
1734         spi_res_release(ctlr, mesg);
1735
1736         if (ctlr->cur_msg_prepared && ctlr->unprepare_message) {
1737                 ret = ctlr->unprepare_message(ctlr, mesg);
1738                 if (ret) {
1739                         dev_err(&ctlr->dev, "failed to unprepare message: %d\n",
1740                                 ret);
1741                 }
1742         }
1743
1744         spin_lock_irqsave(&ctlr->queue_lock, flags);
1745         ctlr->cur_msg = NULL;
1746         ctlr->cur_msg_prepared = false;
1747         ctlr->fallback = false;
1748         kthread_queue_work(ctlr->kworker, &ctlr->pump_messages);
1749         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1750
1751         trace_spi_message_done(mesg);
1752
1753         mesg->state = NULL;
1754         if (mesg->complete)
1755                 mesg->complete(mesg->context);
1756 }
1757 EXPORT_SYMBOL_GPL(spi_finalize_current_message);
1758
1759 static int spi_start_queue(struct spi_controller *ctlr)
1760 {
1761         unsigned long flags;
1762
1763         spin_lock_irqsave(&ctlr->queue_lock, flags);
1764
1765         if (ctlr->running || ctlr->busy) {
1766                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1767                 return -EBUSY;
1768         }
1769
1770         ctlr->running = true;
1771         ctlr->cur_msg = NULL;
1772         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1773
1774         kthread_queue_work(ctlr->kworker, &ctlr->pump_messages);
1775
1776         return 0;
1777 }
1778
1779 static int spi_stop_queue(struct spi_controller *ctlr)
1780 {
1781         unsigned long flags;
1782         unsigned limit = 500;
1783         int ret = 0;
1784
1785         spin_lock_irqsave(&ctlr->queue_lock, flags);
1786
1787         /*
1788          * This is a bit lame, but is optimized for the common execution path.
1789          * A wait_queue on the ctlr->busy could be used, but then the common
1790          * execution path (pump_messages) would be required to call wake_up or
1791          * friends on every SPI message. Do this instead.
1792          */
1793         while ((!list_empty(&ctlr->queue) || ctlr->busy) && limit--) {
1794                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1795                 usleep_range(10000, 11000);
1796                 spin_lock_irqsave(&ctlr->queue_lock, flags);
1797         }
1798
1799         if (!list_empty(&ctlr->queue) || ctlr->busy)
1800                 ret = -EBUSY;
1801         else
1802                 ctlr->running = false;
1803
1804         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1805
1806         if (ret) {
1807                 dev_warn(&ctlr->dev, "could not stop message queue\n");
1808                 return ret;
1809         }
1810         return ret;
1811 }
1812
1813 static int spi_destroy_queue(struct spi_controller *ctlr)
1814 {
1815         int ret;
1816
1817         ret = spi_stop_queue(ctlr);
1818
1819         /*
1820          * kthread_flush_worker will block until all work is done.
1821          * If the reason that stop_queue timed out is that the work will never
1822          * finish, then it does no good to call flush/stop thread, so
1823          * return anyway.
1824          */
1825         if (ret) {
1826                 dev_err(&ctlr->dev, "problem destroying queue\n");
1827                 return ret;
1828         }
1829
1830         kthread_destroy_worker(ctlr->kworker);
1831
1832         return 0;
1833 }
1834
1835 static int __spi_queued_transfer(struct spi_device *spi,
1836                                  struct spi_message *msg,
1837                                  bool need_pump)
1838 {
1839         struct spi_controller *ctlr = spi->controller;
1840         unsigned long flags;
1841
1842         spin_lock_irqsave(&ctlr->queue_lock, flags);
1843
1844         if (!ctlr->running) {
1845                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1846                 return -ESHUTDOWN;
1847         }
1848         msg->actual_length = 0;
1849         msg->status = -EINPROGRESS;
1850
1851         list_add_tail(&msg->queue, &ctlr->queue);
1852         if (!ctlr->busy && need_pump)
1853                 kthread_queue_work(ctlr->kworker, &ctlr->pump_messages);
1854
1855         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1856         return 0;
1857 }
1858
1859 /**
1860  * spi_queued_transfer - transfer function for queued transfers
1861  * @spi: spi device which is requesting transfer
1862  * @msg: spi message which is to handled is queued to driver queue
1863  *
1864  * Return: zero on success, else a negative error code.
1865  */
1866 static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
1867 {
1868         return __spi_queued_transfer(spi, msg, true);
1869 }
1870
1871 static int spi_controller_initialize_queue(struct spi_controller *ctlr)
1872 {
1873         int ret;
1874
1875         ctlr->transfer = spi_queued_transfer;
1876         if (!ctlr->transfer_one_message)
1877                 ctlr->transfer_one_message = spi_transfer_one_message;
1878
1879         /* Initialize and start queue */
1880         ret = spi_init_queue(ctlr);
1881         if (ret) {
1882                 dev_err(&ctlr->dev, "problem initializing queue\n");
1883                 goto err_init_queue;
1884         }
1885         ctlr->queued = true;
1886         ret = spi_start_queue(ctlr);
1887         if (ret) {
1888                 dev_err(&ctlr->dev, "problem starting queue\n");
1889                 goto err_start_queue;
1890         }
1891
1892         return 0;
1893
1894 err_start_queue:
1895         spi_destroy_queue(ctlr);
1896 err_init_queue:
1897         return ret;
1898 }
1899
1900 /**
1901  * spi_flush_queue - Send all pending messages in the queue from the callers'
1902  *                   context
1903  * @ctlr: controller to process queue for
1904  *
1905  * This should be used when one wants to ensure all pending messages have been
1906  * sent before doing something. Is used by the spi-mem code to make sure SPI
1907  * memory operations do not preempt regular SPI transfers that have been queued
1908  * before the spi-mem operation.
1909  */
1910 void spi_flush_queue(struct spi_controller *ctlr)
1911 {
1912         if (ctlr->transfer == spi_queued_transfer)
1913                 __spi_pump_messages(ctlr, false);
1914 }
1915
1916 /*-------------------------------------------------------------------------*/
1917
1918 #if defined(CONFIG_OF)
1919 static int of_spi_parse_dt(struct spi_controller *ctlr, struct spi_device *spi,
1920                            struct device_node *nc)
1921 {
1922         u32 value;
1923         int rc;
1924
1925         /* Mode (clock phase/polarity/etc.) */
1926         if (of_property_read_bool(nc, "spi-cpha"))
1927                 spi->mode |= SPI_CPHA;
1928         if (of_property_read_bool(nc, "spi-cpol"))
1929                 spi->mode |= SPI_CPOL;
1930         if (of_property_read_bool(nc, "spi-3wire"))
1931                 spi->mode |= SPI_3WIRE;
1932         if (of_property_read_bool(nc, "spi-lsb-first"))
1933                 spi->mode |= SPI_LSB_FIRST;
1934         if (of_property_read_bool(nc, "spi-cs-high"))
1935                 spi->mode |= SPI_CS_HIGH;
1936
1937         /* Device DUAL/QUAD mode */
1938         if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) {
1939                 switch (value) {
1940                 case 0:
1941                         spi->mode |= SPI_NO_TX;
1942                         break;
1943                 case 1:
1944                         break;
1945                 case 2:
1946                         spi->mode |= SPI_TX_DUAL;
1947                         break;
1948                 case 4:
1949                         spi->mode |= SPI_TX_QUAD;
1950                         break;
1951                 case 8:
1952                         spi->mode |= SPI_TX_OCTAL;
1953                         break;
1954                 default:
1955                         dev_warn(&ctlr->dev,
1956                                 "spi-tx-bus-width %d not supported\n",
1957                                 value);
1958                         break;
1959                 }
1960         }
1961
1962         if (!of_property_read_u32(nc, "spi-rx-bus-width", &value)) {
1963                 switch (value) {
1964                 case 0:
1965                         spi->mode |= SPI_NO_RX;
1966                         break;
1967                 case 1:
1968                         break;
1969                 case 2:
1970                         spi->mode |= SPI_RX_DUAL;
1971                         break;
1972                 case 4:
1973                         spi->mode |= SPI_RX_QUAD;
1974                         break;
1975                 case 8:
1976                         spi->mode |= SPI_RX_OCTAL;
1977                         break;
1978                 default:
1979                         dev_warn(&ctlr->dev,
1980                                 "spi-rx-bus-width %d not supported\n",
1981                                 value);
1982                         break;
1983                 }
1984         }
1985
1986         if (spi_controller_is_slave(ctlr)) {
1987                 if (!of_node_name_eq(nc, "slave")) {
1988                         dev_err(&ctlr->dev, "%pOF is not called 'slave'\n",
1989                                 nc);
1990                         return -EINVAL;
1991                 }
1992                 return 0;
1993         }
1994
1995         /* Device address */
1996         rc = of_property_read_u32(nc, "reg", &value);
1997         if (rc) {
1998                 dev_err(&ctlr->dev, "%pOF has no valid 'reg' property (%d)\n",
1999                         nc, rc);
2000                 return rc;
2001         }
2002         spi->chip_select = value;
2003
2004         /* Device speed */
2005         if (!of_property_read_u32(nc, "spi-max-frequency", &value))
2006                 spi->max_speed_hz = value;
2007
2008         return 0;
2009 }
2010
2011 static struct spi_device *
2012 of_register_spi_device(struct spi_controller *ctlr, struct device_node *nc)
2013 {
2014         struct spi_device *spi;
2015         int rc;
2016
2017         /* Alloc an spi_device */
2018         spi = spi_alloc_device(ctlr);
2019         if (!spi) {
2020                 dev_err(&ctlr->dev, "spi_device alloc error for %pOF\n", nc);
2021                 rc = -ENOMEM;
2022                 goto err_out;
2023         }
2024
2025         /* Select device driver */
2026         rc = of_modalias_node(nc, spi->modalias,
2027                                 sizeof(spi->modalias));
2028         if (rc < 0) {
2029                 dev_err(&ctlr->dev, "cannot find modalias for %pOF\n", nc);
2030                 goto err_out;
2031         }
2032
2033         rc = of_spi_parse_dt(ctlr, spi, nc);
2034         if (rc)
2035                 goto err_out;
2036
2037         /* Store a pointer to the node in the device structure */
2038         of_node_get(nc);
2039         spi->dev.of_node = nc;
2040
2041         /* Register the new device */
2042         rc = spi_add_device(spi);
2043         if (rc) {
2044                 dev_err(&ctlr->dev, "spi_device register error %pOF\n", nc);
2045                 goto err_of_node_put;
2046         }
2047
2048         return spi;
2049
2050 err_of_node_put:
2051         of_node_put(nc);
2052 err_out:
2053         spi_dev_put(spi);
2054         return ERR_PTR(rc);
2055 }
2056
2057 /**
2058  * of_register_spi_devices() - Register child devices onto the SPI bus
2059  * @ctlr:       Pointer to spi_controller device
2060  *
2061  * Registers an spi_device for each child node of controller node which
2062  * represents a valid SPI slave.
2063  */
2064 static void of_register_spi_devices(struct spi_controller *ctlr)
2065 {
2066         struct spi_device *spi;
2067         struct device_node *nc;
2068
2069         if (!ctlr->dev.of_node)
2070                 return;
2071
2072         for_each_available_child_of_node(ctlr->dev.of_node, nc) {
2073                 if (of_node_test_and_set_flag(nc, OF_POPULATED))
2074                         continue;
2075                 spi = of_register_spi_device(ctlr, nc);
2076                 if (IS_ERR(spi)) {
2077                         dev_warn(&ctlr->dev,
2078                                  "Failed to create SPI device for %pOF\n", nc);
2079                         of_node_clear_flag(nc, OF_POPULATED);
2080                 }
2081         }
2082 }
2083 #else
2084 static void of_register_spi_devices(struct spi_controller *ctlr) { }
2085 #endif
2086
2087 #ifdef CONFIG_ACPI
2088 struct acpi_spi_lookup {
2089         struct spi_controller   *ctlr;
2090         u32                     max_speed_hz;
2091         u32                     mode;
2092         int                     irq;
2093         u8                      bits_per_word;
2094         u8                      chip_select;
2095 };
2096
2097 static void acpi_spi_parse_apple_properties(struct acpi_device *dev,
2098                                             struct acpi_spi_lookup *lookup)
2099 {
2100         const union acpi_object *obj;
2101
2102         if (!x86_apple_machine)
2103                 return;
2104
2105         if (!acpi_dev_get_property(dev, "spiSclkPeriod", ACPI_TYPE_BUFFER, &obj)
2106             && obj->buffer.length >= 4)
2107                 lookup->max_speed_hz  = NSEC_PER_SEC / *(u32 *)obj->buffer.pointer;
2108
2109         if (!acpi_dev_get_property(dev, "spiWordSize", ACPI_TYPE_BUFFER, &obj)
2110             && obj->buffer.length == 8)
2111                 lookup->bits_per_word = *(u64 *)obj->buffer.pointer;
2112
2113         if (!acpi_dev_get_property(dev, "spiBitOrder", ACPI_TYPE_BUFFER, &obj)
2114             && obj->buffer.length == 8 && !*(u64 *)obj->buffer.pointer)
2115                 lookup->mode |= SPI_LSB_FIRST;
2116
2117         if (!acpi_dev_get_property(dev, "spiSPO", ACPI_TYPE_BUFFER, &obj)
2118             && obj->buffer.length == 8 &&  *(u64 *)obj->buffer.pointer)
2119                 lookup->mode |= SPI_CPOL;
2120
2121         if (!acpi_dev_get_property(dev, "spiSPH", ACPI_TYPE_BUFFER, &obj)
2122             && obj->buffer.length == 8 &&  *(u64 *)obj->buffer.pointer)
2123                 lookup->mode |= SPI_CPHA;
2124 }
2125
2126 static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
2127 {
2128         struct acpi_spi_lookup *lookup = data;
2129         struct spi_controller *ctlr = lookup->ctlr;
2130
2131         if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
2132                 struct acpi_resource_spi_serialbus *sb;
2133                 acpi_handle parent_handle;
2134                 acpi_status status;
2135
2136                 sb = &ares->data.spi_serial_bus;
2137                 if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) {
2138
2139                         status = acpi_get_handle(NULL,
2140                                                  sb->resource_source.string_ptr,
2141                                                  &parent_handle);
2142
2143                         if (ACPI_FAILURE(status) ||
2144                             ACPI_HANDLE(ctlr->dev.parent) != parent_handle)
2145                                 return -ENODEV;
2146
2147                         /*
2148                          * ACPI DeviceSelection numbering is handled by the
2149                          * host controller driver in Windows and can vary
2150                          * from driver to driver. In Linux we always expect
2151                          * 0 .. max - 1 so we need to ask the driver to
2152                          * translate between the two schemes.
2153                          */
2154                         if (ctlr->fw_translate_cs) {
2155                                 int cs = ctlr->fw_translate_cs(ctlr,
2156                                                 sb->device_selection);
2157                                 if (cs < 0)
2158                                         return cs;
2159                                 lookup->chip_select = cs;
2160                         } else {
2161                                 lookup->chip_select = sb->device_selection;
2162                         }
2163
2164                         lookup->max_speed_hz = sb->connection_speed;
2165                         lookup->bits_per_word = sb->data_bit_length;
2166
2167                         if (sb->clock_phase == ACPI_SPI_SECOND_PHASE)
2168                                 lookup->mode |= SPI_CPHA;
2169                         if (sb->clock_polarity == ACPI_SPI_START_HIGH)
2170                                 lookup->mode |= SPI_CPOL;
2171                         if (sb->device_polarity == ACPI_SPI_ACTIVE_HIGH)
2172                                 lookup->mode |= SPI_CS_HIGH;
2173                 }
2174         } else if (lookup->irq < 0) {
2175                 struct resource r;
2176
2177                 if (acpi_dev_resource_interrupt(ares, 0, &r))
2178                         lookup->irq = r.start;
2179         }
2180
2181         /* Always tell the ACPI core to skip this resource */
2182         return 1;
2183 }
2184
2185 static acpi_status acpi_register_spi_device(struct spi_controller *ctlr,
2186                                             struct acpi_device *adev)
2187 {
2188         acpi_handle parent_handle = NULL;
2189         struct list_head resource_list;
2190         struct acpi_spi_lookup lookup = {};
2191         struct spi_device *spi;
2192         int ret;
2193
2194         if (acpi_bus_get_status(adev) || !adev->status.present ||
2195             acpi_device_enumerated(adev))
2196                 return AE_OK;
2197
2198         lookup.ctlr             = ctlr;
2199         lookup.irq              = -1;
2200
2201         INIT_LIST_HEAD(&resource_list);
2202         ret = acpi_dev_get_resources(adev, &resource_list,
2203                                      acpi_spi_add_resource, &lookup);
2204         acpi_dev_free_resource_list(&resource_list);
2205
2206         if (ret < 0)
2207                 /* found SPI in _CRS but it points to another controller */
2208                 return AE_OK;
2209
2210         if (!lookup.max_speed_hz &&
2211             ACPI_SUCCESS(acpi_get_parent(adev->handle, &parent_handle)) &&
2212             ACPI_HANDLE(ctlr->dev.parent) == parent_handle) {
2213                 /* Apple does not use _CRS but nested devices for SPI slaves */
2214                 acpi_spi_parse_apple_properties(adev, &lookup);
2215         }
2216
2217         if (!lookup.max_speed_hz)
2218                 return AE_OK;
2219
2220         spi = spi_alloc_device(ctlr);
2221         if (!spi) {
2222                 dev_err(&ctlr->dev, "failed to allocate SPI device for %s\n",
2223                         dev_name(&adev->dev));
2224                 return AE_NO_MEMORY;
2225         }
2226
2227
2228         ACPI_COMPANION_SET(&spi->dev, adev);
2229         spi->max_speed_hz       = lookup.max_speed_hz;
2230         spi->mode               |= lookup.mode;
2231         spi->irq                = lookup.irq;
2232         spi->bits_per_word      = lookup.bits_per_word;
2233         spi->chip_select        = lookup.chip_select;
2234
2235         acpi_set_modalias(adev, acpi_device_hid(adev), spi->modalias,
2236                           sizeof(spi->modalias));
2237
2238         if (spi->irq < 0)
2239                 spi->irq = acpi_dev_gpio_irq_get(adev, 0);
2240
2241         acpi_device_set_enumerated(adev);
2242
2243         adev->power.flags.ignore_parent = true;
2244         if (spi_add_device(spi)) {
2245                 adev->power.flags.ignore_parent = false;
2246                 dev_err(&ctlr->dev, "failed to add SPI device %s from ACPI\n",
2247                         dev_name(&adev->dev));
2248                 spi_dev_put(spi);
2249         }
2250
2251         return AE_OK;
2252 }
2253
2254 static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level,
2255                                        void *data, void **return_value)
2256 {
2257         struct spi_controller *ctlr = data;
2258         struct acpi_device *adev;
2259
2260         if (acpi_bus_get_device(handle, &adev))
2261                 return AE_OK;
2262
2263         return acpi_register_spi_device(ctlr, adev);
2264 }
2265
2266 #define SPI_ACPI_ENUMERATE_MAX_DEPTH            32
2267
2268 static void acpi_register_spi_devices(struct spi_controller *ctlr)
2269 {
2270         acpi_status status;
2271         acpi_handle handle;
2272
2273         handle = ACPI_HANDLE(ctlr->dev.parent);
2274         if (!handle)
2275                 return;
2276
2277         status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
2278                                      SPI_ACPI_ENUMERATE_MAX_DEPTH,
2279                                      acpi_spi_add_device, NULL, ctlr, NULL);
2280         if (ACPI_FAILURE(status))
2281                 dev_warn(&ctlr->dev, "failed to enumerate SPI slaves\n");
2282 }
2283 #else
2284 static inline void acpi_register_spi_devices(struct spi_controller *ctlr) {}
2285 #endif /* CONFIG_ACPI */
2286
2287 static void spi_controller_release(struct device *dev)
2288 {
2289         struct spi_controller *ctlr;
2290
2291         ctlr = container_of(dev, struct spi_controller, dev);
2292         kfree(ctlr);
2293 }
2294
2295 static struct class spi_master_class = {
2296         .name           = "spi_master",
2297         .owner          = THIS_MODULE,
2298         .dev_release    = spi_controller_release,
2299         .dev_groups     = spi_master_groups,
2300 };
2301
2302 #ifdef CONFIG_SPI_SLAVE
2303 /**
2304  * spi_slave_abort - abort the ongoing transfer request on an SPI slave
2305  *                   controller
2306  * @spi: device used for the current transfer
2307  */
2308 int spi_slave_abort(struct spi_device *spi)
2309 {
2310         struct spi_controller *ctlr = spi->controller;
2311
2312         if (spi_controller_is_slave(ctlr) && ctlr->slave_abort)
2313                 return ctlr->slave_abort(ctlr);
2314
2315         return -ENOTSUPP;
2316 }
2317 EXPORT_SYMBOL_GPL(spi_slave_abort);
2318
2319 static int match_true(struct device *dev, void *data)
2320 {
2321         return 1;
2322 }
2323
2324 static ssize_t slave_show(struct device *dev, struct device_attribute *attr,
2325                           char *buf)
2326 {
2327         struct spi_controller *ctlr = container_of(dev, struct spi_controller,
2328                                                    dev);
2329         struct device *child;
2330
2331         child = device_find_child(&ctlr->dev, NULL, match_true);
2332         return sprintf(buf, "%s\n",
2333                        child ? to_spi_device(child)->modalias : NULL);
2334 }
2335
2336 static ssize_t slave_store(struct device *dev, struct device_attribute *attr,
2337                            const char *buf, size_t count)
2338 {
2339         struct spi_controller *ctlr = container_of(dev, struct spi_controller,
2340                                                    dev);
2341         struct spi_device *spi;
2342         struct device *child;
2343         char name[32];
2344         int rc;
2345
2346         rc = sscanf(buf, "%31s", name);
2347         if (rc != 1 || !name[0])
2348                 return -EINVAL;
2349
2350         child = device_find_child(&ctlr->dev, NULL, match_true);
2351         if (child) {
2352                 /* Remove registered slave */
2353                 device_unregister(child);
2354                 put_device(child);
2355         }
2356
2357         if (strcmp(name, "(null)")) {
2358                 /* Register new slave */
2359                 spi = spi_alloc_device(ctlr);
2360                 if (!spi)
2361                         return -ENOMEM;
2362
2363                 strlcpy(spi->modalias, name, sizeof(spi->modalias));
2364
2365                 rc = spi_add_device(spi);
2366                 if (rc) {
2367                         spi_dev_put(spi);
2368                         return rc;
2369                 }
2370         }
2371
2372         return count;
2373 }
2374
2375 static DEVICE_ATTR_RW(slave);
2376
2377 static struct attribute *spi_slave_attrs[] = {
2378         &dev_attr_slave.attr,
2379         NULL,
2380 };
2381
2382 static const struct attribute_group spi_slave_group = {
2383         .attrs = spi_slave_attrs,
2384 };
2385
2386 static const struct attribute_group *spi_slave_groups[] = {
2387         &spi_controller_statistics_group,
2388         &spi_slave_group,
2389         NULL,
2390 };
2391
2392 static struct class spi_slave_class = {
2393         .name           = "spi_slave",
2394         .owner          = THIS_MODULE,
2395         .dev_release    = spi_controller_release,
2396         .dev_groups     = spi_slave_groups,
2397 };
2398 #else
2399 extern struct class spi_slave_class;    /* dummy */
2400 #endif
2401
2402 /**
2403  * __spi_alloc_controller - allocate an SPI master or slave controller
2404  * @dev: the controller, possibly using the platform_bus
2405  * @size: how much zeroed driver-private data to allocate; the pointer to this
2406  *      memory is in the driver_data field of the returned device, accessible
2407  *      with spi_controller_get_devdata(); the memory is cacheline aligned;
2408  *      drivers granting DMA access to portions of their private data need to
2409  *      round up @size using ALIGN(size, dma_get_cache_alignment()).
2410  * @slave: flag indicating whether to allocate an SPI master (false) or SPI
2411  *      slave (true) controller
2412  * Context: can sleep
2413  *
2414  * This call is used only by SPI controller drivers, which are the
2415  * only ones directly touching chip registers.  It's how they allocate
2416  * an spi_controller structure, prior to calling spi_register_controller().
2417  *
2418  * This must be called from context that can sleep.
2419  *
2420  * The caller is responsible for assigning the bus number and initializing the
2421  * controller's methods before calling spi_register_controller(); and (after
2422  * errors adding the device) calling spi_controller_put() to prevent a memory
2423  * leak.
2424  *
2425  * Return: the SPI controller structure on success, else NULL.
2426  */
2427 struct spi_controller *__spi_alloc_controller(struct device *dev,
2428                                               unsigned int size, bool slave)
2429 {
2430         struct spi_controller   *ctlr;
2431         size_t ctlr_size = ALIGN(sizeof(*ctlr), dma_get_cache_alignment());
2432
2433         if (!dev)
2434                 return NULL;
2435
2436         ctlr = kzalloc(size + ctlr_size, GFP_KERNEL);
2437         if (!ctlr)
2438                 return NULL;
2439
2440         device_initialize(&ctlr->dev);
2441         ctlr->bus_num = -1;
2442         ctlr->num_chipselect = 1;
2443         ctlr->slave = slave;
2444         if (IS_ENABLED(CONFIG_SPI_SLAVE) && slave)
2445                 ctlr->dev.class = &spi_slave_class;
2446         else
2447                 ctlr->dev.class = &spi_master_class;
2448         ctlr->dev.parent = dev;
2449         pm_suspend_ignore_children(&ctlr->dev, true);
2450         spi_controller_set_devdata(ctlr, (void *)ctlr + ctlr_size);
2451
2452         return ctlr;
2453 }
2454 EXPORT_SYMBOL_GPL(__spi_alloc_controller);
2455
2456 static void devm_spi_release_controller(struct device *dev, void *ctlr)
2457 {
2458         spi_controller_put(*(struct spi_controller **)ctlr);
2459 }
2460
2461 /**
2462  * __devm_spi_alloc_controller - resource-managed __spi_alloc_controller()
2463  * @dev: physical device of SPI controller
2464  * @size: how much zeroed driver-private data to allocate
2465  * @slave: whether to allocate an SPI master (false) or SPI slave (true)
2466  * Context: can sleep
2467  *
2468  * Allocate an SPI controller and automatically release a reference on it
2469  * when @dev is unbound from its driver.  Drivers are thus relieved from
2470  * having to call spi_controller_put().
2471  *
2472  * The arguments to this function are identical to __spi_alloc_controller().
2473  *
2474  * Return: the SPI controller structure on success, else NULL.
2475  */
2476 struct spi_controller *__devm_spi_alloc_controller(struct device *dev,
2477                                                    unsigned int size,
2478                                                    bool slave)
2479 {
2480         struct spi_controller **ptr, *ctlr;
2481
2482         ptr = devres_alloc(devm_spi_release_controller, sizeof(*ptr),
2483                            GFP_KERNEL);
2484         if (!ptr)
2485                 return NULL;
2486
2487         ctlr = __spi_alloc_controller(dev, size, slave);
2488         if (ctlr) {
2489                 ctlr->devm_allocated = true;
2490                 *ptr = ctlr;
2491                 devres_add(dev, ptr);
2492         } else {
2493                 devres_free(ptr);
2494         }
2495
2496         return ctlr;
2497 }
2498 EXPORT_SYMBOL_GPL(__devm_spi_alloc_controller);
2499
2500 #ifdef CONFIG_OF
2501 static int of_spi_get_gpio_numbers(struct spi_controller *ctlr)
2502 {
2503         int nb, i, *cs;
2504         struct device_node *np = ctlr->dev.of_node;
2505
2506         if (!np)
2507                 return 0;
2508
2509         nb = of_gpio_named_count(np, "cs-gpios");
2510         ctlr->num_chipselect = max_t(int, nb, ctlr->num_chipselect);
2511
2512         /* Return error only for an incorrectly formed cs-gpios property */
2513         if (nb == 0 || nb == -ENOENT)
2514                 return 0;
2515         else if (nb < 0)
2516                 return nb;
2517
2518         cs = devm_kcalloc(&ctlr->dev, ctlr->num_chipselect, sizeof(int),
2519                           GFP_KERNEL);
2520         ctlr->cs_gpios = cs;
2521
2522         if (!ctlr->cs_gpios)
2523                 return -ENOMEM;
2524
2525         for (i = 0; i < ctlr->num_chipselect; i++)
2526                 cs[i] = -ENOENT;
2527
2528         for (i = 0; i < nb; i++)
2529                 cs[i] = of_get_named_gpio(np, "cs-gpios", i);
2530
2531         return 0;
2532 }
2533 #else
2534 static int of_spi_get_gpio_numbers(struct spi_controller *ctlr)
2535 {
2536         return 0;
2537 }
2538 #endif
2539
2540 /**
2541  * spi_get_gpio_descs() - grab chip select GPIOs for the master
2542  * @ctlr: The SPI master to grab GPIO descriptors for
2543  */
2544 static int spi_get_gpio_descs(struct spi_controller *ctlr)
2545 {
2546         int nb, i;
2547         struct gpio_desc **cs;
2548         struct device *dev = &ctlr->dev;
2549         unsigned long native_cs_mask = 0;
2550         unsigned int num_cs_gpios = 0;
2551
2552         nb = gpiod_count(dev, "cs");
2553         if (nb < 0) {
2554                 /* No GPIOs at all is fine, else return the error */
2555                 if (nb == -ENOENT)
2556                         return 0;
2557                 return nb;
2558         }
2559
2560         ctlr->num_chipselect = max_t(int, nb, ctlr->num_chipselect);
2561
2562         cs = devm_kcalloc(dev, ctlr->num_chipselect, sizeof(*cs),
2563                           GFP_KERNEL);
2564         if (!cs)
2565                 return -ENOMEM;
2566         ctlr->cs_gpiods = cs;
2567
2568         for (i = 0; i < nb; i++) {
2569                 /*
2570                  * Most chipselects are active low, the inverted
2571                  * semantics are handled by special quirks in gpiolib,
2572                  * so initializing them GPIOD_OUT_LOW here means
2573                  * "unasserted", in most cases this will drive the physical
2574                  * line high.
2575                  */
2576                 cs[i] = devm_gpiod_get_index_optional(dev, "cs", i,
2577                                                       GPIOD_OUT_LOW);
2578                 if (IS_ERR(cs[i]))
2579                         return PTR_ERR(cs[i]);
2580
2581                 if (cs[i]) {
2582                         /*
2583                          * If we find a CS GPIO, name it after the device and
2584                          * chip select line.
2585                          */
2586                         char *gpioname;
2587
2588                         gpioname = devm_kasprintf(dev, GFP_KERNEL, "%s CS%d",
2589                                                   dev_name(dev), i);
2590                         if (!gpioname)
2591                                 return -ENOMEM;
2592                         gpiod_set_consumer_name(cs[i], gpioname);
2593                         num_cs_gpios++;
2594                         continue;
2595                 }
2596
2597                 if (ctlr->max_native_cs && i >= ctlr->max_native_cs) {
2598                         dev_err(dev, "Invalid native chip select %d\n", i);
2599                         return -EINVAL;
2600                 }
2601                 native_cs_mask |= BIT(i);
2602         }
2603
2604         ctlr->unused_native_cs = ffz(native_cs_mask);
2605         if (num_cs_gpios && ctlr->max_native_cs &&
2606             ctlr->unused_native_cs >= ctlr->max_native_cs) {
2607                 dev_err(dev, "No unused native chip select available\n");
2608                 return -EINVAL;
2609         }
2610
2611         return 0;
2612 }
2613
2614 static int spi_controller_check_ops(struct spi_controller *ctlr)
2615 {
2616         /*
2617          * The controller may implement only the high-level SPI-memory like
2618          * operations if it does not support regular SPI transfers, and this is
2619          * valid use case.
2620          * If ->mem_ops is NULL, we request that at least one of the
2621          * ->transfer_xxx() method be implemented.
2622          */
2623         if (ctlr->mem_ops) {
2624                 if (!ctlr->mem_ops->exec_op)
2625                         return -EINVAL;
2626         } else if (!ctlr->transfer && !ctlr->transfer_one &&
2627                    !ctlr->transfer_one_message) {
2628                 return -EINVAL;
2629         }
2630
2631         return 0;
2632 }
2633
2634 /**
2635  * spi_register_controller - register SPI master or slave controller
2636  * @ctlr: initialized master, originally from spi_alloc_master() or
2637  *      spi_alloc_slave()
2638  * Context: can sleep
2639  *
2640  * SPI controllers connect to their drivers using some non-SPI bus,
2641  * such as the platform bus.  The final stage of probe() in that code
2642  * includes calling spi_register_controller() to hook up to this SPI bus glue.
2643  *
2644  * SPI controllers use board specific (often SOC specific) bus numbers,
2645  * and board-specific addressing for SPI devices combines those numbers
2646  * with chip select numbers.  Since SPI does not directly support dynamic
2647  * device identification, boards need configuration tables telling which
2648  * chip is at which address.
2649  *
2650  * This must be called from context that can sleep.  It returns zero on
2651  * success, else a negative error code (dropping the controller's refcount).
2652  * After a successful return, the caller is responsible for calling
2653  * spi_unregister_controller().
2654  *
2655  * Return: zero on success, else a negative error code.
2656  */
2657 int spi_register_controller(struct spi_controller *ctlr)
2658 {
2659         struct device           *dev = ctlr->dev.parent;
2660         struct boardinfo        *bi;
2661         int                     status;
2662         int                     id, first_dynamic;
2663
2664         if (!dev)
2665                 return -ENODEV;
2666
2667         /*
2668          * Make sure all necessary hooks are implemented before registering
2669          * the SPI controller.
2670          */
2671         status = spi_controller_check_ops(ctlr);
2672         if (status)
2673                 return status;
2674
2675         if (ctlr->bus_num >= 0) {
2676                 /* devices with a fixed bus num must check-in with the num */
2677                 mutex_lock(&board_lock);
2678                 id = idr_alloc(&spi_master_idr, ctlr, ctlr->bus_num,
2679                         ctlr->bus_num + 1, GFP_KERNEL);
2680                 mutex_unlock(&board_lock);
2681                 if (WARN(id < 0, "couldn't get idr"))
2682                         return id == -ENOSPC ? -EBUSY : id;
2683                 ctlr->bus_num = id;
2684         } else if (ctlr->dev.of_node) {
2685                 /* allocate dynamic bus number using Linux idr */
2686                 id = of_alias_get_id(ctlr->dev.of_node, "spi");
2687                 if (id >= 0) {
2688                         ctlr->bus_num = id;
2689                         mutex_lock(&board_lock);
2690                         id = idr_alloc(&spi_master_idr, ctlr, ctlr->bus_num,
2691                                        ctlr->bus_num + 1, GFP_KERNEL);
2692                         mutex_unlock(&board_lock);
2693                         if (WARN(id < 0, "couldn't get idr"))
2694                                 return id == -ENOSPC ? -EBUSY : id;
2695                 }
2696         }
2697         if (ctlr->bus_num < 0) {
2698                 first_dynamic = of_alias_get_highest_id("spi");
2699                 if (first_dynamic < 0)
2700                         first_dynamic = 0;
2701                 else
2702                         first_dynamic++;
2703
2704                 mutex_lock(&board_lock);
2705                 id = idr_alloc(&spi_master_idr, ctlr, first_dynamic,
2706                                0, GFP_KERNEL);
2707                 mutex_unlock(&board_lock);
2708                 if (WARN(id < 0, "couldn't get idr"))
2709                         return id;
2710                 ctlr->bus_num = id;
2711         }
2712         INIT_LIST_HEAD(&ctlr->queue);
2713         spin_lock_init(&ctlr->queue_lock);
2714         spin_lock_init(&ctlr->bus_lock_spinlock);
2715         mutex_init(&ctlr->bus_lock_mutex);
2716         mutex_init(&ctlr->io_mutex);
2717         ctlr->bus_lock_flag = 0;
2718         init_completion(&ctlr->xfer_completion);
2719         if (!ctlr->max_dma_len)
2720                 ctlr->max_dma_len = INT_MAX;
2721
2722         /* register the device, then userspace will see it.
2723          * registration fails if the bus ID is in use.
2724          */
2725         dev_set_name(&ctlr->dev, "spi%u", ctlr->bus_num);
2726
2727         if (!spi_controller_is_slave(ctlr)) {
2728                 if (ctlr->use_gpio_descriptors) {
2729                         status = spi_get_gpio_descs(ctlr);
2730                         if (status)
2731                                 goto free_bus_id;
2732                         /*
2733                          * A controller using GPIO descriptors always
2734                          * supports SPI_CS_HIGH if need be.
2735                          */
2736                         ctlr->mode_bits |= SPI_CS_HIGH;
2737                 } else {
2738                         /* Legacy code path for GPIOs from DT */
2739                         status = of_spi_get_gpio_numbers(ctlr);
2740                         if (status)
2741                                 goto free_bus_id;
2742                 }
2743         }
2744
2745         /*
2746          * Even if it's just one always-selected device, there must
2747          * be at least one chipselect.
2748          */
2749         if (!ctlr->num_chipselect) {
2750                 status = -EINVAL;
2751                 goto free_bus_id;
2752         }
2753
2754         status = device_add(&ctlr->dev);
2755         if (status < 0)
2756                 goto free_bus_id;
2757         dev_dbg(dev, "registered %s %s\n",
2758                         spi_controller_is_slave(ctlr) ? "slave" : "master",
2759                         dev_name(&ctlr->dev));
2760
2761         /*
2762          * If we're using a queued driver, start the queue. Note that we don't
2763          * need the queueing logic if the driver is only supporting high-level
2764          * memory operations.
2765          */
2766         if (ctlr->transfer) {
2767                 dev_info(dev, "controller is unqueued, this is deprecated\n");
2768         } else if (ctlr->transfer_one || ctlr->transfer_one_message) {
2769                 status = spi_controller_initialize_queue(ctlr);
2770                 if (status) {
2771                         device_del(&ctlr->dev);
2772                         goto free_bus_id;
2773                 }
2774         }
2775         /* add statistics */
2776         spin_lock_init(&ctlr->statistics.lock);
2777
2778         mutex_lock(&board_lock);
2779         list_add_tail(&ctlr->list, &spi_controller_list);
2780         list_for_each_entry(bi, &board_list, list)
2781                 spi_match_controller_to_boardinfo(ctlr, &bi->board_info);
2782         mutex_unlock(&board_lock);
2783
2784         /* Register devices from the device tree and ACPI */
2785         of_register_spi_devices(ctlr);
2786         acpi_register_spi_devices(ctlr);
2787         return status;
2788
2789 free_bus_id:
2790         mutex_lock(&board_lock);
2791         idr_remove(&spi_master_idr, ctlr->bus_num);
2792         mutex_unlock(&board_lock);
2793         return status;
2794 }
2795 EXPORT_SYMBOL_GPL(spi_register_controller);
2796
2797 static void devm_spi_unregister(void *ctlr)
2798 {
2799         spi_unregister_controller(ctlr);
2800 }
2801
2802 /**
2803  * devm_spi_register_controller - register managed SPI master or slave
2804  *      controller
2805  * @dev:    device managing SPI controller
2806  * @ctlr: initialized controller, originally from spi_alloc_master() or
2807  *      spi_alloc_slave()
2808  * Context: can sleep
2809  *
2810  * Register a SPI device as with spi_register_controller() which will
2811  * automatically be unregistered and freed.
2812  *
2813  * Return: zero on success, else a negative error code.
2814  */
2815 int devm_spi_register_controller(struct device *dev,
2816                                  struct spi_controller *ctlr)
2817 {
2818         int ret;
2819
2820         ret = spi_register_controller(ctlr);
2821         if (ret)
2822                 return ret;
2823
2824         return devm_add_action_or_reset(dev, devm_spi_unregister, ctlr);
2825 }
2826 EXPORT_SYMBOL_GPL(devm_spi_register_controller);
2827
2828 static int __unregister(struct device *dev, void *null)
2829 {
2830         spi_unregister_device(to_spi_device(dev));
2831         return 0;
2832 }
2833
2834 /**
2835  * spi_unregister_controller - unregister SPI master or slave controller
2836  * @ctlr: the controller being unregistered
2837  * Context: can sleep
2838  *
2839  * This call is used only by SPI controller drivers, which are the
2840  * only ones directly touching chip registers.
2841  *
2842  * This must be called from context that can sleep.
2843  *
2844  * Note that this function also drops a reference to the controller.
2845  */
2846 void spi_unregister_controller(struct spi_controller *ctlr)
2847 {
2848         struct spi_controller *found;
2849         int id = ctlr->bus_num;
2850
2851         /* Prevent addition of new devices, unregister existing ones */
2852         if (IS_ENABLED(CONFIG_SPI_DYNAMIC))
2853                 mutex_lock(&spi_add_lock);
2854
2855         device_for_each_child(&ctlr->dev, NULL, __unregister);
2856
2857         /* First make sure that this controller was ever added */
2858         mutex_lock(&board_lock);
2859         found = idr_find(&spi_master_idr, id);
2860         mutex_unlock(&board_lock);
2861         if (ctlr->queued) {
2862                 if (spi_destroy_queue(ctlr))
2863                         dev_err(&ctlr->dev, "queue remove failed\n");
2864         }
2865         mutex_lock(&board_lock);
2866         list_del(&ctlr->list);
2867         mutex_unlock(&board_lock);
2868
2869         device_del(&ctlr->dev);
2870
2871         /* Release the last reference on the controller if its driver
2872          * has not yet been converted to devm_spi_alloc_master/slave().
2873          */
2874         if (!ctlr->devm_allocated)
2875                 put_device(&ctlr->dev);
2876
2877         /* free bus id */
2878         mutex_lock(&board_lock);
2879         if (found == ctlr)
2880                 idr_remove(&spi_master_idr, id);
2881         mutex_unlock(&board_lock);
2882
2883         if (IS_ENABLED(CONFIG_SPI_DYNAMIC))
2884                 mutex_unlock(&spi_add_lock);
2885 }
2886 EXPORT_SYMBOL_GPL(spi_unregister_controller);
2887
2888 int spi_controller_suspend(struct spi_controller *ctlr)
2889 {
2890         int ret;
2891
2892         /* Basically no-ops for non-queued controllers */
2893         if (!ctlr->queued)
2894                 return 0;
2895
2896         ret = spi_stop_queue(ctlr);
2897         if (ret)
2898                 dev_err(&ctlr->dev, "queue stop failed\n");
2899
2900         return ret;
2901 }
2902 EXPORT_SYMBOL_GPL(spi_controller_suspend);
2903
2904 int spi_controller_resume(struct spi_controller *ctlr)
2905 {
2906         int ret;
2907
2908         if (!ctlr->queued)
2909                 return 0;
2910
2911         ret = spi_start_queue(ctlr);
2912         if (ret)
2913                 dev_err(&ctlr->dev, "queue restart failed\n");
2914
2915         return ret;
2916 }
2917 EXPORT_SYMBOL_GPL(spi_controller_resume);
2918
2919 static int __spi_controller_match(struct device *dev, const void *data)
2920 {
2921         struct spi_controller *ctlr;
2922         const u16 *bus_num = data;
2923
2924         ctlr = container_of(dev, struct spi_controller, dev);
2925         return ctlr->bus_num == *bus_num;
2926 }
2927
2928 /**
2929  * spi_busnum_to_master - look up master associated with bus_num
2930  * @bus_num: the master's bus number
2931  * Context: can sleep
2932  *
2933  * This call may be used with devices that are registered after
2934  * arch init time.  It returns a refcounted pointer to the relevant
2935  * spi_controller (which the caller must release), or NULL if there is
2936  * no such master registered.
2937  *
2938  * Return: the SPI master structure on success, else NULL.
2939  */
2940 struct spi_controller *spi_busnum_to_master(u16 bus_num)
2941 {
2942         struct device           *dev;
2943         struct spi_controller   *ctlr = NULL;
2944
2945         dev = class_find_device(&spi_master_class, NULL, &bus_num,
2946                                 __spi_controller_match);
2947         if (dev)
2948                 ctlr = container_of(dev, struct spi_controller, dev);
2949         /* reference got in class_find_device */
2950         return ctlr;
2951 }
2952 EXPORT_SYMBOL_GPL(spi_busnum_to_master);
2953
2954 /*-------------------------------------------------------------------------*/
2955
2956 /* Core methods for SPI resource management */
2957
2958 /**
2959  * spi_res_alloc - allocate a spi resource that is life-cycle managed
2960  *                 during the processing of a spi_message while using
2961  *                 spi_transfer_one
2962  * @spi:     the spi device for which we allocate memory
2963  * @release: the release code to execute for this resource
2964  * @size:    size to alloc and return
2965  * @gfp:     GFP allocation flags
2966  *
2967  * Return: the pointer to the allocated data
2968  *
2969  * This may get enhanced in the future to allocate from a memory pool
2970  * of the @spi_device or @spi_controller to avoid repeated allocations.
2971  */
2972 void *spi_res_alloc(struct spi_device *spi,
2973                     spi_res_release_t release,
2974                     size_t size, gfp_t gfp)
2975 {
2976         struct spi_res *sres;
2977
2978         sres = kzalloc(sizeof(*sres) + size, gfp);
2979         if (!sres)
2980                 return NULL;
2981
2982         INIT_LIST_HEAD(&sres->entry);
2983         sres->release = release;
2984
2985         return sres->data;
2986 }
2987 EXPORT_SYMBOL_GPL(spi_res_alloc);
2988
2989 /**
2990  * spi_res_free - free an spi resource
2991  * @res: pointer to the custom data of a resource
2992  *
2993  */
2994 void spi_res_free(void *res)
2995 {
2996         struct spi_res *sres = container_of(res, struct spi_res, data);
2997
2998         if (!res)
2999                 return;
3000
3001         WARN_ON(!list_empty(&sres->entry));
3002         kfree(sres);
3003 }
3004 EXPORT_SYMBOL_GPL(spi_res_free);
3005
3006 /**
3007  * spi_res_add - add a spi_res to the spi_message
3008  * @message: the spi message
3009  * @res:     the spi_resource
3010  */
3011 void spi_res_add(struct spi_message *message, void *res)
3012 {
3013         struct spi_res *sres = container_of(res, struct spi_res, data);
3014
3015         WARN_ON(!list_empty(&sres->entry));
3016         list_add_tail(&sres->entry, &message->resources);
3017 }
3018 EXPORT_SYMBOL_GPL(spi_res_add);
3019
3020 /**
3021  * spi_res_release - release all spi resources for this message
3022  * @ctlr:  the @spi_controller
3023  * @message: the @spi_message
3024  */
3025 void spi_res_release(struct spi_controller *ctlr, struct spi_message *message)
3026 {
3027         struct spi_res *res, *tmp;
3028
3029         list_for_each_entry_safe_reverse(res, tmp, &message->resources, entry) {
3030                 if (res->release)
3031                         res->release(ctlr, message, res->data);
3032
3033                 list_del(&res->entry);
3034
3035                 kfree(res);
3036         }
3037 }
3038 EXPORT_SYMBOL_GPL(spi_res_release);
3039
3040 /*-------------------------------------------------------------------------*/
3041
3042 /* Core methods for spi_message alterations */
3043
3044 static void __spi_replace_transfers_release(struct spi_controller *ctlr,
3045                                             struct spi_message *msg,
3046                                             void *res)
3047 {
3048         struct spi_replaced_transfers *rxfer = res;
3049         size_t i;
3050
3051         /* call extra callback if requested */
3052         if (rxfer->release)
3053                 rxfer->release(ctlr, msg, res);
3054
3055         /* insert replaced transfers back into the message */
3056         list_splice(&rxfer->replaced_transfers, rxfer->replaced_after);
3057
3058         /* remove the formerly inserted entries */
3059         for (i = 0; i < rxfer->inserted; i++)
3060                 list_del(&rxfer->inserted_transfers[i].transfer_list);
3061 }
3062
3063 /**
3064  * spi_replace_transfers - replace transfers with several transfers
3065  *                         and register change with spi_message.resources
3066  * @msg:           the spi_message we work upon
3067  * @xfer_first:    the first spi_transfer we want to replace
3068  * @remove:        number of transfers to remove
3069  * @insert:        the number of transfers we want to insert instead
3070  * @release:       extra release code necessary in some circumstances
3071  * @extradatasize: extra data to allocate (with alignment guarantees
3072  *                 of struct @spi_transfer)
3073  * @gfp:           gfp flags
3074  *
3075  * Returns: pointer to @spi_replaced_transfers,
3076  *          PTR_ERR(...) in case of errors.
3077  */
3078 struct spi_replaced_transfers *spi_replace_transfers(
3079         struct spi_message *msg,
3080         struct spi_transfer *xfer_first,
3081         size_t remove,
3082         size_t insert,
3083         spi_replaced_release_t release,
3084         size_t extradatasize,
3085         gfp_t gfp)
3086 {
3087         struct spi_replaced_transfers *rxfer;
3088         struct spi_transfer *xfer;
3089         size_t i;
3090
3091         /* allocate the structure using spi_res */
3092         rxfer = spi_res_alloc(msg->spi, __spi_replace_transfers_release,
3093                               struct_size(rxfer, inserted_transfers, insert)
3094                               + extradatasize,
3095                               gfp);
3096         if (!rxfer)
3097                 return ERR_PTR(-ENOMEM);
3098
3099         /* the release code to invoke before running the generic release */
3100         rxfer->release = release;
3101
3102         /* assign extradata */
3103         if (extradatasize)
3104                 rxfer->extradata =
3105                         &rxfer->inserted_transfers[insert];
3106
3107         /* init the replaced_transfers list */
3108         INIT_LIST_HEAD(&rxfer->replaced_transfers);
3109
3110         /* assign the list_entry after which we should reinsert
3111          * the @replaced_transfers - it may be spi_message.messages!
3112          */
3113         rxfer->replaced_after = xfer_first->transfer_list.prev;
3114
3115         /* remove the requested number of transfers */
3116         for (i = 0; i < remove; i++) {
3117                 /* if the entry after replaced_after it is msg->transfers
3118                  * then we have been requested to remove more transfers
3119                  * than are in the list
3120                  */
3121                 if (rxfer->replaced_after->next == &msg->transfers) {
3122                         dev_err(&msg->spi->dev,
3123                                 "requested to remove more spi_transfers than are available\n");
3124                         /* insert replaced transfers back into the message */
3125                         list_splice(&rxfer->replaced_transfers,
3126                                     rxfer->replaced_after);
3127
3128                         /* free the spi_replace_transfer structure */
3129                         spi_res_free(rxfer);
3130
3131                         /* and return with an error */
3132                         return ERR_PTR(-EINVAL);
3133                 }
3134
3135                 /* remove the entry after replaced_after from list of
3136                  * transfers and add it to list of replaced_transfers
3137                  */
3138                 list_move_tail(rxfer->replaced_after->next,
3139                                &rxfer->replaced_transfers);
3140         }
3141
3142         /* create copy of the given xfer with identical settings
3143          * based on the first transfer to get removed
3144          */
3145         for (i = 0; i < insert; i++) {
3146                 /* we need to run in reverse order */
3147                 xfer = &rxfer->inserted_transfers[insert - 1 - i];
3148
3149                 /* copy all spi_transfer data */
3150                 memcpy(xfer, xfer_first, sizeof(*xfer));
3151
3152                 /* add to list */
3153                 list_add(&xfer->transfer_list, rxfer->replaced_after);
3154
3155                 /* clear cs_change and delay for all but the last */
3156                 if (i) {
3157                         xfer->cs_change = false;
3158                         xfer->delay.value = 0;
3159                 }
3160         }
3161
3162         /* set up inserted */
3163         rxfer->inserted = insert;
3164
3165         /* and register it with spi_res/spi_message */
3166         spi_res_add(msg, rxfer);
3167
3168         return rxfer;
3169 }
3170 EXPORT_SYMBOL_GPL(spi_replace_transfers);
3171
3172 static int __spi_split_transfer_maxsize(struct spi_controller *ctlr,
3173                                         struct spi_message *msg,
3174                                         struct spi_transfer **xferp,
3175                                         size_t maxsize,
3176                                         gfp_t gfp)
3177 {
3178         struct spi_transfer *xfer = *xferp, *xfers;
3179         struct spi_replaced_transfers *srt;
3180         size_t offset;
3181         size_t count, i;
3182
3183         /* calculate how many we have to replace */
3184         count = DIV_ROUND_UP(xfer->len, maxsize);
3185
3186         /* create replacement */
3187         srt = spi_replace_transfers(msg, xfer, 1, count, NULL, 0, gfp);
3188         if (IS_ERR(srt))
3189                 return PTR_ERR(srt);
3190         xfers = srt->inserted_transfers;
3191
3192         /* now handle each of those newly inserted spi_transfers
3193          * note that the replacements spi_transfers all are preset
3194          * to the same values as *xferp, so tx_buf, rx_buf and len
3195          * are all identical (as well as most others)
3196          * so we just have to fix up len and the pointers.
3197          *
3198          * this also includes support for the depreciated
3199          * spi_message.is_dma_mapped interface
3200          */
3201
3202         /* the first transfer just needs the length modified, so we
3203          * run it outside the loop
3204          */
3205         xfers[0].len = min_t(size_t, maxsize, xfer[0].len);
3206
3207         /* all the others need rx_buf/tx_buf also set */
3208         for (i = 1, offset = maxsize; i < count; offset += maxsize, i++) {
3209                 /* update rx_buf, tx_buf and dma */
3210                 if (xfers[i].rx_buf)
3211                         xfers[i].rx_buf += offset;
3212                 if (xfers[i].rx_dma)
3213                         xfers[i].rx_dma += offset;
3214                 if (xfers[i].tx_buf)
3215                         xfers[i].tx_buf += offset;
3216                 if (xfers[i].tx_dma)
3217                         xfers[i].tx_dma += offset;
3218
3219                 /* update length */
3220                 xfers[i].len = min(maxsize, xfers[i].len - offset);
3221         }
3222
3223         /* we set up xferp to the last entry we have inserted,
3224          * so that we skip those already split transfers
3225          */
3226         *xferp = &xfers[count - 1];
3227
3228         /* increment statistics counters */
3229         SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics,
3230                                        transfers_split_maxsize);
3231         SPI_STATISTICS_INCREMENT_FIELD(&msg->spi->statistics,
3232                                        transfers_split_maxsize);
3233
3234         return 0;
3235 }
3236
3237 /**
3238  * spi_split_transfers_maxsize - split spi transfers into multiple transfers
3239  *                               when an individual transfer exceeds a
3240  *                               certain size
3241  * @ctlr:    the @spi_controller for this transfer
3242  * @msg:   the @spi_message to transform
3243  * @maxsize:  the maximum when to apply this
3244  * @gfp: GFP allocation flags
3245  *
3246  * Return: status of transformation
3247  */
3248 int spi_split_transfers_maxsize(struct spi_controller *ctlr,
3249                                 struct spi_message *msg,
3250                                 size_t maxsize,
3251                                 gfp_t gfp)
3252 {
3253         struct spi_transfer *xfer;
3254         int ret;
3255
3256         /* iterate over the transfer_list,
3257          * but note that xfer is advanced to the last transfer inserted
3258          * to avoid checking sizes again unnecessarily (also xfer does
3259          * potentiall belong to a different list by the time the
3260          * replacement has happened
3261          */
3262         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
3263                 if (xfer->len > maxsize) {
3264                         ret = __spi_split_transfer_maxsize(ctlr, msg, &xfer,
3265                                                            maxsize, gfp);
3266                         if (ret)
3267                                 return ret;
3268                 }
3269         }
3270
3271         return 0;
3272 }
3273 EXPORT_SYMBOL_GPL(spi_split_transfers_maxsize);
3274
3275 /*-------------------------------------------------------------------------*/
3276
3277 /* Core methods for SPI controller protocol drivers.  Some of the
3278  * other core methods are currently defined as inline functions.
3279  */
3280
3281 static int __spi_validate_bits_per_word(struct spi_controller *ctlr,
3282                                         u8 bits_per_word)
3283 {
3284         if (ctlr->bits_per_word_mask) {
3285                 /* Only 32 bits fit in the mask */
3286                 if (bits_per_word > 32)
3287                         return -EINVAL;
3288                 if (!(ctlr->bits_per_word_mask & SPI_BPW_MASK(bits_per_word)))
3289                         return -EINVAL;
3290         }
3291
3292         return 0;
3293 }
3294
3295 /**
3296  * spi_setup - setup SPI mode and clock rate
3297  * @spi: the device whose settings are being modified
3298  * Context: can sleep, and no requests are queued to the device
3299  *
3300  * SPI protocol drivers may need to update the transfer mode if the
3301  * device doesn't work with its default.  They may likewise need
3302  * to update clock rates or word sizes from initial values.  This function
3303  * changes those settings, and must be called from a context that can sleep.
3304  * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
3305  * effect the next time the device is selected and data is transferred to
3306  * or from it.  When this function returns, the spi device is deselected.
3307  *
3308  * Note that this call will fail if the protocol driver specifies an option
3309  * that the underlying controller or its driver does not support.  For
3310  * example, not all hardware supports wire transfers using nine bit words,
3311  * LSB-first wire encoding, or active-high chipselects.
3312  *
3313  * Return: zero on success, else a negative error code.
3314  */
3315 int spi_setup(struct spi_device *spi)
3316 {
3317         unsigned        bad_bits, ugly_bits;
3318         int             status;
3319
3320         /*
3321          * check mode to prevent that any two of DUAL, QUAD and NO_MOSI/MISO
3322          * are set at the same time
3323          */
3324         if ((hweight_long(spi->mode &
3325                 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_NO_TX)) > 1) ||
3326             (hweight_long(spi->mode &
3327                 (SPI_RX_DUAL | SPI_RX_QUAD | SPI_NO_RX)) > 1)) {
3328                 dev_err(&spi->dev,
3329                 "setup: can not select any two of dual, quad and no-rx/tx at the same time\n");
3330                 return -EINVAL;
3331         }
3332         /* if it is SPI_3WIRE mode, DUAL and QUAD should be forbidden
3333          */
3334         if ((spi->mode & SPI_3WIRE) && (spi->mode &
3335                 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_TX_OCTAL |
3336                  SPI_RX_DUAL | SPI_RX_QUAD | SPI_RX_OCTAL)))
3337                 return -EINVAL;
3338         /* help drivers fail *cleanly* when they need options
3339          * that aren't supported with their current controller
3340          * SPI_CS_WORD has a fallback software implementation,
3341          * so it is ignored here.
3342          */
3343         bad_bits = spi->mode & ~(spi->controller->mode_bits | SPI_CS_WORD |
3344                                  SPI_NO_TX | SPI_NO_RX);
3345         /* nothing prevents from working with active-high CS in case if it
3346          * is driven by GPIO.
3347          */
3348         if (gpio_is_valid(spi->cs_gpio))
3349                 bad_bits &= ~SPI_CS_HIGH;
3350         ugly_bits = bad_bits &
3351                     (SPI_TX_DUAL | SPI_TX_QUAD | SPI_TX_OCTAL |
3352                      SPI_RX_DUAL | SPI_RX_QUAD | SPI_RX_OCTAL);
3353         if (ugly_bits) {
3354                 dev_warn(&spi->dev,
3355                          "setup: ignoring unsupported mode bits %x\n",
3356                          ugly_bits);
3357                 spi->mode &= ~ugly_bits;
3358                 bad_bits &= ~ugly_bits;
3359         }
3360         if (bad_bits) {
3361                 dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
3362                         bad_bits);
3363                 return -EINVAL;
3364         }
3365
3366         if (!spi->bits_per_word)
3367                 spi->bits_per_word = 8;
3368
3369         status = __spi_validate_bits_per_word(spi->controller,
3370                                               spi->bits_per_word);
3371         if (status)
3372                 return status;
3373
3374         if (spi->controller->max_speed_hz &&
3375             (!spi->max_speed_hz ||
3376              spi->max_speed_hz > spi->controller->max_speed_hz))
3377                 spi->max_speed_hz = spi->controller->max_speed_hz;
3378
3379         mutex_lock(&spi->controller->io_mutex);
3380
3381         if (spi->controller->setup) {
3382                 status = spi->controller->setup(spi);
3383                 if (status) {
3384                         mutex_unlock(&spi->controller->io_mutex);
3385                         dev_err(&spi->controller->dev, "Failed to setup device: %d\n",
3386                                 status);
3387                         return status;
3388                 }
3389         }
3390
3391         if (spi->controller->auto_runtime_pm && spi->controller->set_cs) {
3392                 status = pm_runtime_get_sync(spi->controller->dev.parent);
3393                 if (status < 0) {
3394                         mutex_unlock(&spi->controller->io_mutex);
3395                         pm_runtime_put_noidle(spi->controller->dev.parent);
3396                         dev_err(&spi->controller->dev, "Failed to power device: %d\n",
3397                                 status);
3398                         return status;
3399                 }
3400
3401                 /*
3402                  * We do not want to return positive value from pm_runtime_get,
3403                  * there are many instances of devices calling spi_setup() and
3404                  * checking for a non-zero return value instead of a negative
3405                  * return value.
3406                  */
3407                 status = 0;
3408
3409                 spi_set_cs(spi, false, true);
3410                 pm_runtime_mark_last_busy(spi->controller->dev.parent);
3411                 pm_runtime_put_autosuspend(spi->controller->dev.parent);
3412         } else {
3413                 spi_set_cs(spi, false, true);
3414         }
3415
3416         mutex_unlock(&spi->controller->io_mutex);
3417
3418         if (spi->rt && !spi->controller->rt) {
3419                 spi->controller->rt = true;
3420                 spi_set_thread_rt(spi->controller);
3421         }
3422
3423         dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
3424                         (int) (spi->mode & (SPI_CPOL | SPI_CPHA)),
3425                         (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
3426                         (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
3427                         (spi->mode & SPI_3WIRE) ? "3wire, " : "",
3428                         (spi->mode & SPI_LOOP) ? "loopback, " : "",
3429                         spi->bits_per_word, spi->max_speed_hz,
3430                         status);
3431
3432         return status;
3433 }
3434 EXPORT_SYMBOL_GPL(spi_setup);
3435
3436 /**
3437  * spi_set_cs_timing - configure CS setup, hold, and inactive delays
3438  * @spi: the device that requires specific CS timing configuration
3439  * @setup: CS setup time specified via @spi_delay
3440  * @hold: CS hold time specified via @spi_delay
3441  * @inactive: CS inactive delay between transfers specified via @spi_delay
3442  *
3443  * Return: zero on success, else a negative error code.
3444  */
3445 int spi_set_cs_timing(struct spi_device *spi, struct spi_delay *setup,
3446                       struct spi_delay *hold, struct spi_delay *inactive)
3447 {
3448         struct device *parent = spi->controller->dev.parent;
3449         size_t len;
3450         int status;
3451
3452         if (spi->controller->set_cs_timing &&
3453             !(spi->cs_gpiod || gpio_is_valid(spi->cs_gpio))) {
3454                 if (spi->controller->auto_runtime_pm) {
3455                         status = pm_runtime_get_sync(parent);
3456                         if (status < 0) {
3457                                 pm_runtime_put_noidle(parent);
3458                                 dev_err(&spi->controller->dev, "Failed to power device: %d\n",
3459                                         status);
3460                                 return status;
3461                         }
3462
3463                         status = spi->controller->set_cs_timing(spi, setup,
3464                                                                 hold, inactive);
3465                         pm_runtime_mark_last_busy(parent);
3466                         pm_runtime_put_autosuspend(parent);
3467                         return status;
3468                 } else {
3469                         return spi->controller->set_cs_timing(spi, setup, hold,
3470                                                               inactive);
3471                 }
3472         }
3473
3474         if ((setup && setup->unit == SPI_DELAY_UNIT_SCK) ||
3475             (hold && hold->unit == SPI_DELAY_UNIT_SCK) ||
3476             (inactive && inactive->unit == SPI_DELAY_UNIT_SCK)) {
3477                 dev_err(&spi->dev,
3478                         "Clock-cycle delays for CS not supported in SW mode\n");
3479                 return -ENOTSUPP;
3480         }
3481
3482         len = sizeof(struct spi_delay);
3483
3484         /* copy delays to controller */
3485         if (setup)
3486                 memcpy(&spi->controller->cs_setup, setup, len);
3487         else
3488                 memset(&spi->controller->cs_setup, 0, len);
3489
3490         if (hold)
3491                 memcpy(&spi->controller->cs_hold, hold, len);
3492         else
3493                 memset(&spi->controller->cs_hold, 0, len);
3494
3495         if (inactive)
3496                 memcpy(&spi->controller->cs_inactive, inactive, len);
3497         else
3498                 memset(&spi->controller->cs_inactive, 0, len);
3499
3500         return 0;
3501 }
3502 EXPORT_SYMBOL_GPL(spi_set_cs_timing);
3503
3504 static int _spi_xfer_word_delay_update(struct spi_transfer *xfer,
3505                                        struct spi_device *spi)
3506 {
3507         int delay1, delay2;
3508
3509         delay1 = spi_delay_to_ns(&xfer->word_delay, xfer);
3510         if (delay1 < 0)
3511                 return delay1;
3512
3513         delay2 = spi_delay_to_ns(&spi->word_delay, xfer);
3514         if (delay2 < 0)
3515                 return delay2;
3516
3517         if (delay1 < delay2)
3518                 memcpy(&xfer->word_delay, &spi->word_delay,
3519                        sizeof(xfer->word_delay));
3520
3521         return 0;
3522 }
3523
3524 static int __spi_validate(struct spi_device *spi, struct spi_message *message)
3525 {
3526         struct spi_controller *ctlr = spi->controller;
3527         struct spi_transfer *xfer;
3528         int w_size;
3529
3530         if (list_empty(&message->transfers))
3531                 return -EINVAL;
3532
3533         /* If an SPI controller does not support toggling the CS line on each
3534          * transfer (indicated by the SPI_CS_WORD flag) or we are using a GPIO
3535          * for the CS line, we can emulate the CS-per-word hardware function by
3536          * splitting transfers into one-word transfers and ensuring that
3537          * cs_change is set for each transfer.
3538          */
3539         if ((spi->mode & SPI_CS_WORD) && (!(ctlr->mode_bits & SPI_CS_WORD) ||
3540                                           spi->cs_gpiod ||
3541                                           gpio_is_valid(spi->cs_gpio))) {
3542                 size_t maxsize;
3543                 int ret;
3544
3545                 maxsize = (spi->bits_per_word + 7) / 8;
3546
3547                 /* spi_split_transfers_maxsize() requires message->spi */
3548                 message->spi = spi;
3549
3550                 ret = spi_split_transfers_maxsize(ctlr, message, maxsize,
3551                                                   GFP_KERNEL);
3552                 if (ret)
3553                         return ret;
3554
3555                 list_for_each_entry(xfer, &message->transfers, transfer_list) {
3556                         /* don't change cs_change on the last entry in the list */
3557                         if (list_is_last(&xfer->transfer_list, &message->transfers))
3558                                 break;
3559                         xfer->cs_change = 1;
3560                 }
3561         }
3562
3563         /* Half-duplex links include original MicroWire, and ones with
3564          * only one data pin like SPI_3WIRE (switches direction) or where
3565          * either MOSI or MISO is missing.  They can also be caused by
3566          * software limitations.
3567          */
3568         if ((ctlr->flags & SPI_CONTROLLER_HALF_DUPLEX) ||
3569             (spi->mode & SPI_3WIRE)) {
3570                 unsigned flags = ctlr->flags;
3571
3572                 list_for_each_entry(xfer, &message->transfers, transfer_list) {
3573                         if (xfer->rx_buf && xfer->tx_buf)
3574                                 return -EINVAL;
3575                         if ((flags & SPI_CONTROLLER_NO_TX) && xfer->tx_buf)
3576                                 return -EINVAL;
3577                         if ((flags & SPI_CONTROLLER_NO_RX) && xfer->rx_buf)
3578                                 return -EINVAL;
3579                 }
3580         }
3581
3582         /**
3583          * Set transfer bits_per_word and max speed as spi device default if
3584          * it is not set for this transfer.
3585          * Set transfer tx_nbits and rx_nbits as single transfer default
3586          * (SPI_NBITS_SINGLE) if it is not set for this transfer.
3587          * Ensure transfer word_delay is at least as long as that required by
3588          * device itself.
3589          */
3590         message->frame_length = 0;
3591         list_for_each_entry(xfer, &message->transfers, transfer_list) {
3592                 xfer->effective_speed_hz = 0;
3593                 message->frame_length += xfer->len;
3594                 if (!xfer->bits_per_word)
3595                         xfer->bits_per_word = spi->bits_per_word;
3596
3597                 if (!xfer->speed_hz)
3598                         xfer->speed_hz = spi->max_speed_hz;
3599
3600                 if (ctlr->max_speed_hz && xfer->speed_hz > ctlr->max_speed_hz)
3601                         xfer->speed_hz = ctlr->max_speed_hz;
3602
3603                 if (__spi_validate_bits_per_word(ctlr, xfer->bits_per_word))
3604                         return -EINVAL;
3605
3606                 /*
3607                  * SPI transfer length should be multiple of SPI word size
3608                  * where SPI word size should be power-of-two multiple
3609                  */
3610                 if (xfer->bits_per_word <= 8)
3611                         w_size = 1;
3612                 else if (xfer->bits_per_word <= 16)
3613                         w_size = 2;
3614                 else
3615                         w_size = 4;
3616
3617                 /* No partial transfers accepted */
3618                 if (xfer->len % w_size)
3619                         return -EINVAL;
3620
3621                 if (xfer->speed_hz && ctlr->min_speed_hz &&
3622                     xfer->speed_hz < ctlr->min_speed_hz)
3623                         return -EINVAL;
3624
3625                 if (xfer->tx_buf && !xfer->tx_nbits)
3626                         xfer->tx_nbits = SPI_NBITS_SINGLE;
3627                 if (xfer->rx_buf && !xfer->rx_nbits)
3628                         xfer->rx_nbits = SPI_NBITS_SINGLE;
3629                 /* check transfer tx/rx_nbits:
3630                  * 1. check the value matches one of single, dual and quad
3631                  * 2. check tx/rx_nbits match the mode in spi_device
3632                  */
3633                 if (xfer->tx_buf) {
3634                         if (spi->mode & SPI_NO_TX)
3635                                 return -EINVAL;
3636                         if (xfer->tx_nbits != SPI_NBITS_SINGLE &&
3637                                 xfer->tx_nbits != SPI_NBITS_DUAL &&
3638                                 xfer->tx_nbits != SPI_NBITS_QUAD)
3639                                 return -EINVAL;
3640                         if ((xfer->tx_nbits == SPI_NBITS_DUAL) &&
3641                                 !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
3642                                 return -EINVAL;
3643                         if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
3644                                 !(spi->mode & SPI_TX_QUAD))
3645                                 return -EINVAL;
3646                 }
3647                 /* check transfer rx_nbits */
3648                 if (xfer->rx_buf) {
3649                         if (spi->mode & SPI_NO_RX)
3650                                 return -EINVAL;
3651                         if (xfer->rx_nbits != SPI_NBITS_SINGLE &&
3652                                 xfer->rx_nbits != SPI_NBITS_DUAL &&
3653                                 xfer->rx_nbits != SPI_NBITS_QUAD)
3654                                 return -EINVAL;
3655                         if ((xfer->rx_nbits == SPI_NBITS_DUAL) &&
3656                                 !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
3657                                 return -EINVAL;
3658                         if ((xfer->rx_nbits == SPI_NBITS_QUAD) &&
3659                                 !(spi->mode & SPI_RX_QUAD))
3660                                 return -EINVAL;
3661                 }
3662
3663                 if (_spi_xfer_word_delay_update(xfer, spi))
3664                         return -EINVAL;
3665         }
3666
3667         message->status = -EINPROGRESS;
3668
3669         return 0;
3670 }
3671
3672 static int __spi_async(struct spi_device *spi, struct spi_message *message)
3673 {
3674         struct spi_controller *ctlr = spi->controller;
3675         struct spi_transfer *xfer;
3676
3677         /*
3678          * Some controllers do not support doing regular SPI transfers. Return
3679          * ENOTSUPP when this is the case.
3680          */
3681         if (!ctlr->transfer)
3682                 return -ENOTSUPP;
3683
3684         message->spi = spi;
3685
3686         SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics, spi_async);
3687         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_async);
3688
3689         trace_spi_message_submit(message);
3690
3691         if (!ctlr->ptp_sts_supported) {
3692                 list_for_each_entry(xfer, &message->transfers, transfer_list) {
3693                         xfer->ptp_sts_word_pre = 0;
3694                         ptp_read_system_prets(xfer->ptp_sts);
3695                 }
3696         }
3697
3698         return ctlr->transfer(spi, message);
3699 }
3700
3701 /**
3702  * spi_async - asynchronous SPI transfer
3703  * @spi: device with which data will be exchanged
3704  * @message: describes the data transfers, including completion callback
3705  * Context: any (irqs may be blocked, etc)
3706  *
3707  * This call may be used in_irq and other contexts which can't sleep,
3708  * as well as from task contexts which can sleep.
3709  *
3710  * The completion callback is invoked in a context which can't sleep.
3711  * Before that invocation, the value of message->status is undefined.
3712  * When the callback is issued, message->status holds either zero (to
3713  * indicate complete success) or a negative error code.  After that
3714  * callback returns, the driver which issued the transfer request may
3715  * deallocate the associated memory; it's no longer in use by any SPI
3716  * core or controller driver code.
3717  *
3718  * Note that although all messages to a spi_device are handled in
3719  * FIFO order, messages may go to different devices in other orders.
3720  * Some device might be higher priority, or have various "hard" access
3721  * time requirements, for example.
3722  *
3723  * On detection of any fault during the transfer, processing of
3724  * the entire message is aborted, and the device is deselected.
3725  * Until returning from the associated message completion callback,
3726  * no other spi_message queued to that device will be processed.
3727  * (This rule applies equally to all the synchronous transfer calls,
3728  * which are wrappers around this core asynchronous primitive.)
3729  *
3730  * Return: zero on success, else a negative error code.
3731  */
3732 int spi_async(struct spi_device *spi, struct spi_message *message)
3733 {
3734         struct spi_controller *ctlr = spi->controller;
3735         int ret;
3736         unsigned long flags;
3737
3738         ret = __spi_validate(spi, message);
3739         if (ret != 0)
3740                 return ret;
3741
3742         spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
3743
3744         if (ctlr->bus_lock_flag)
3745                 ret = -EBUSY;
3746         else
3747                 ret = __spi_async(spi, message);
3748
3749         spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3750
3751         return ret;
3752 }
3753 EXPORT_SYMBOL_GPL(spi_async);
3754
3755 /**
3756  * spi_async_locked - version of spi_async with exclusive bus usage
3757  * @spi: device with which data will be exchanged
3758  * @message: describes the data transfers, including completion callback
3759  * Context: any (irqs may be blocked, etc)
3760  *
3761  * This call may be used in_irq and other contexts which can't sleep,
3762  * as well as from task contexts which can sleep.
3763  *
3764  * The completion callback is invoked in a context which can't sleep.
3765  * Before that invocation, the value of message->status is undefined.
3766  * When the callback is issued, message->status holds either zero (to
3767  * indicate complete success) or a negative error code.  After that
3768  * callback returns, the driver which issued the transfer request may
3769  * deallocate the associated memory; it's no longer in use by any SPI
3770  * core or controller driver code.
3771  *
3772  * Note that although all messages to a spi_device are handled in
3773  * FIFO order, messages may go to different devices in other orders.
3774  * Some device might be higher priority, or have various "hard" access
3775  * time requirements, for example.
3776  *
3777  * On detection of any fault during the transfer, processing of
3778  * the entire message is aborted, and the device is deselected.
3779  * Until returning from the associated message completion callback,
3780  * no other spi_message queued to that device will be processed.
3781  * (This rule applies equally to all the synchronous transfer calls,
3782  * which are wrappers around this core asynchronous primitive.)
3783  *
3784  * Return: zero on success, else a negative error code.
3785  */
3786 int spi_async_locked(struct spi_device *spi, struct spi_message *message)
3787 {
3788         struct spi_controller *ctlr = spi->controller;
3789         int ret;
3790         unsigned long flags;
3791
3792         ret = __spi_validate(spi, message);
3793         if (ret != 0)
3794                 return ret;
3795
3796         spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
3797
3798         ret = __spi_async(spi, message);
3799
3800         spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3801
3802         return ret;
3803
3804 }
3805 EXPORT_SYMBOL_GPL(spi_async_locked);
3806
3807 /*-------------------------------------------------------------------------*/
3808
3809 /* Utility methods for SPI protocol drivers, layered on
3810  * top of the core.  Some other utility methods are defined as
3811  * inline functions.
3812  */
3813
3814 static void spi_complete(void *arg)
3815 {
3816         complete(arg);
3817 }
3818
3819 static int __spi_sync(struct spi_device *spi, struct spi_message *message)
3820 {
3821         DECLARE_COMPLETION_ONSTACK(done);
3822         int status;
3823         struct spi_controller *ctlr = spi->controller;
3824         unsigned long flags;
3825
3826         status = __spi_validate(spi, message);
3827         if (status != 0)
3828                 return status;
3829
3830         message->complete = spi_complete;
3831         message->context = &done;
3832         message->spi = spi;
3833
3834         SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics, spi_sync);
3835         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_sync);
3836
3837         /* If we're not using the legacy transfer method then we will
3838          * try to transfer in the calling context so special case.
3839          * This code would be less tricky if we could remove the
3840          * support for driver implemented message queues.
3841          */
3842         if (ctlr->transfer == spi_queued_transfer) {
3843                 spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
3844
3845                 trace_spi_message_submit(message);
3846
3847                 status = __spi_queued_transfer(spi, message, false);
3848
3849                 spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3850         } else {
3851                 status = spi_async_locked(spi, message);
3852         }
3853
3854         if (status == 0) {
3855                 /* Push out the messages in the calling context if we
3856                  * can.
3857                  */
3858                 if (ctlr->transfer == spi_queued_transfer) {
3859                         SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics,
3860                                                        spi_sync_immediate);
3861                         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics,
3862                                                        spi_sync_immediate);
3863                         __spi_pump_messages(ctlr, false);
3864                 }
3865
3866                 wait_for_completion(&done);
3867                 status = message->status;
3868         }
3869         message->context = NULL;
3870         return status;
3871 }
3872
3873 /**
3874  * spi_sync - blocking/synchronous SPI data transfers
3875  * @spi: device with which data will be exchanged
3876  * @message: describes the data transfers
3877  * Context: can sleep
3878  *
3879  * This call may only be used from a context that may sleep.  The sleep
3880  * is non-interruptible, and has no timeout.  Low-overhead controller
3881  * drivers may DMA directly into and out of the message buffers.
3882  *
3883  * Note that the SPI device's chip select is active during the message,
3884  * and then is normally disabled between messages.  Drivers for some
3885  * frequently-used devices may want to minimize costs of selecting a chip,
3886  * by leaving it selected in anticipation that the next message will go
3887  * to the same chip.  (That may increase power usage.)
3888  *
3889  * Also, the caller is guaranteeing that the memory associated with the
3890  * message will not be freed before this call returns.
3891  *
3892  * Return: zero on success, else a negative error code.
3893  */
3894 int spi_sync(struct spi_device *spi, struct spi_message *message)
3895 {
3896         int ret;
3897
3898         mutex_lock(&spi->controller->bus_lock_mutex);
3899         ret = __spi_sync(spi, message);
3900         mutex_unlock(&spi->controller->bus_lock_mutex);
3901
3902         return ret;
3903 }
3904 EXPORT_SYMBOL_GPL(spi_sync);
3905
3906 /**
3907  * spi_sync_locked - version of spi_sync with exclusive bus usage
3908  * @spi: device with which data will be exchanged
3909  * @message: describes the data transfers
3910  * Context: can sleep
3911  *
3912  * This call may only be used from a context that may sleep.  The sleep
3913  * is non-interruptible, and has no timeout.  Low-overhead controller
3914  * drivers may DMA directly into and out of the message buffers.
3915  *
3916  * This call should be used by drivers that require exclusive access to the
3917  * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
3918  * be released by a spi_bus_unlock call when the exclusive access is over.
3919  *
3920  * Return: zero on success, else a negative error code.
3921  */
3922 int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
3923 {
3924         return __spi_sync(spi, message);
3925 }
3926 EXPORT_SYMBOL_GPL(spi_sync_locked);
3927
3928 /**
3929  * spi_bus_lock - obtain a lock for exclusive SPI bus usage
3930  * @ctlr: SPI bus master that should be locked for exclusive bus access
3931  * Context: can sleep
3932  *
3933  * This call may only be used from a context that may sleep.  The sleep
3934  * is non-interruptible, and has no timeout.
3935  *
3936  * This call should be used by drivers that require exclusive access to the
3937  * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
3938  * exclusive access is over. Data transfer must be done by spi_sync_locked
3939  * and spi_async_locked calls when the SPI bus lock is held.
3940  *
3941  * Return: always zero.
3942  */
3943 int spi_bus_lock(struct spi_controller *ctlr)
3944 {
3945         unsigned long flags;
3946
3947         mutex_lock(&ctlr->bus_lock_mutex);
3948
3949         spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
3950         ctlr->bus_lock_flag = 1;
3951         spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3952
3953         /* mutex remains locked until spi_bus_unlock is called */
3954
3955         return 0;
3956 }
3957 EXPORT_SYMBOL_GPL(spi_bus_lock);
3958
3959 /**
3960  * spi_bus_unlock - release the lock for exclusive SPI bus usage
3961  * @ctlr: SPI bus master that was locked for exclusive bus access
3962  * Context: can sleep
3963  *
3964  * This call may only be used from a context that may sleep.  The sleep
3965  * is non-interruptible, and has no timeout.
3966  *
3967  * This call releases an SPI bus lock previously obtained by an spi_bus_lock
3968  * call.
3969  *
3970  * Return: always zero.
3971  */
3972 int spi_bus_unlock(struct spi_controller *ctlr)
3973 {
3974         ctlr->bus_lock_flag = 0;
3975
3976         mutex_unlock(&ctlr->bus_lock_mutex);
3977
3978         return 0;
3979 }
3980 EXPORT_SYMBOL_GPL(spi_bus_unlock);
3981
3982 /* portable code must never pass more than 32 bytes */
3983 #define SPI_BUFSIZ      max(32, SMP_CACHE_BYTES)
3984
3985 static u8       *buf;
3986
3987 /**
3988  * spi_write_then_read - SPI synchronous write followed by read
3989  * @spi: device with which data will be exchanged
3990  * @txbuf: data to be written (need not be dma-safe)
3991  * @n_tx: size of txbuf, in bytes
3992  * @rxbuf: buffer into which data will be read (need not be dma-safe)
3993  * @n_rx: size of rxbuf, in bytes
3994  * Context: can sleep
3995  *
3996  * This performs a half duplex MicroWire style transaction with the
3997  * device, sending txbuf and then reading rxbuf.  The return value
3998  * is zero for success, else a negative errno status code.
3999  * This call may only be used from a context that may sleep.
4000  *
4001  * Parameters to this routine are always copied using a small buffer.
4002  * Performance-sensitive or bulk transfer code should instead use
4003  * spi_{async,sync}() calls with dma-safe buffers.
4004  *
4005  * Return: zero on success, else a negative error code.
4006  */
4007 int spi_write_then_read(struct spi_device *spi,
4008                 const void *txbuf, unsigned n_tx,
4009                 void *rxbuf, unsigned n_rx)
4010 {
4011         static DEFINE_MUTEX(lock);
4012
4013         int                     status;
4014         struct spi_message      message;
4015         struct spi_transfer     x[2];
4016         u8                      *local_buf;
4017
4018         /* Use preallocated DMA-safe buffer if we can.  We can't avoid
4019          * copying here, (as a pure convenience thing), but we can
4020          * keep heap costs out of the hot path unless someone else is
4021          * using the pre-allocated buffer or the transfer is too large.
4022          */
4023         if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) {
4024                 local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx),
4025                                     GFP_KERNEL | GFP_DMA);
4026                 if (!local_buf)
4027                         return -ENOMEM;
4028         } else {
4029                 local_buf = buf;
4030         }
4031
4032         spi_message_init(&message);
4033         memset(x, 0, sizeof(x));
4034         if (n_tx) {
4035                 x[0].len = n_tx;
4036                 spi_message_add_tail(&x[0], &message);
4037         }
4038         if (n_rx) {
4039                 x[1].len = n_rx;
4040                 spi_message_add_tail(&x[1], &message);
4041         }
4042
4043         memcpy(local_buf, txbuf, n_tx);
4044         x[0].tx_buf = local_buf;
4045         x[1].rx_buf = local_buf + n_tx;
4046
4047         /* do the i/o */
4048         status = spi_sync(spi, &message);
4049         if (status == 0)
4050                 memcpy(rxbuf, x[1].rx_buf, n_rx);
4051
4052         if (x[0].tx_buf == buf)
4053                 mutex_unlock(&lock);
4054         else
4055                 kfree(local_buf);
4056
4057         return status;
4058 }
4059 EXPORT_SYMBOL_GPL(spi_write_then_read);
4060
4061 /*-------------------------------------------------------------------------*/
4062
4063 #if IS_ENABLED(CONFIG_OF)
4064 /* must call put_device() when done with returned spi_device device */
4065 struct spi_device *of_find_spi_device_by_node(struct device_node *node)
4066 {
4067         struct device *dev = bus_find_device_by_of_node(&spi_bus_type, node);
4068
4069         return dev ? to_spi_device(dev) : NULL;
4070 }
4071 EXPORT_SYMBOL_GPL(of_find_spi_device_by_node);
4072 #endif /* IS_ENABLED(CONFIG_OF) */
4073
4074 #if IS_ENABLED(CONFIG_OF_DYNAMIC)
4075 /* the spi controllers are not using spi_bus, so we find it with another way */
4076 static struct spi_controller *of_find_spi_controller_by_node(struct device_node *node)
4077 {
4078         struct device *dev;
4079
4080         dev = class_find_device_by_of_node(&spi_master_class, node);
4081         if (!dev && IS_ENABLED(CONFIG_SPI_SLAVE))
4082                 dev = class_find_device_by_of_node(&spi_slave_class, node);
4083         if (!dev)
4084                 return NULL;
4085
4086         /* reference got in class_find_device */
4087         return container_of(dev, struct spi_controller, dev);
4088 }
4089
4090 static int of_spi_notify(struct notifier_block *nb, unsigned long action,
4091                          void *arg)
4092 {
4093         struct of_reconfig_data *rd = arg;
4094         struct spi_controller *ctlr;
4095         struct spi_device *spi;
4096
4097         switch (of_reconfig_get_state_change(action, arg)) {
4098         case OF_RECONFIG_CHANGE_ADD:
4099                 ctlr = of_find_spi_controller_by_node(rd->dn->parent);
4100                 if (ctlr == NULL)
4101                         return NOTIFY_OK;       /* not for us */
4102
4103                 if (of_node_test_and_set_flag(rd->dn, OF_POPULATED)) {
4104                         put_device(&ctlr->dev);
4105                         return NOTIFY_OK;
4106                 }
4107
4108                 spi = of_register_spi_device(ctlr, rd->dn);
4109                 put_device(&ctlr->dev);
4110
4111                 if (IS_ERR(spi)) {
4112                         pr_err("%s: failed to create for '%pOF'\n",
4113                                         __func__, rd->dn);
4114                         of_node_clear_flag(rd->dn, OF_POPULATED);
4115                         return notifier_from_errno(PTR_ERR(spi));
4116                 }
4117                 break;
4118
4119         case OF_RECONFIG_CHANGE_REMOVE:
4120                 /* already depopulated? */
4121                 if (!of_node_check_flag(rd->dn, OF_POPULATED))
4122                         return NOTIFY_OK;
4123
4124                 /* find our device by node */
4125                 spi = of_find_spi_device_by_node(rd->dn);
4126                 if (spi == NULL)
4127                         return NOTIFY_OK;       /* no? not meant for us */
4128
4129                 /* unregister takes one ref away */
4130                 spi_unregister_device(spi);
4131
4132                 /* and put the reference of the find */
4133                 put_device(&spi->dev);
4134                 break;
4135         }
4136
4137         return NOTIFY_OK;
4138 }
4139
4140 static struct notifier_block spi_of_notifier = {
4141         .notifier_call = of_spi_notify,
4142 };
4143 #else /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
4144 extern struct notifier_block spi_of_notifier;
4145 #endif /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
4146
4147 #if IS_ENABLED(CONFIG_ACPI)
4148 static int spi_acpi_controller_match(struct device *dev, const void *data)
4149 {
4150         return ACPI_COMPANION(dev->parent) == data;
4151 }
4152
4153 static struct spi_controller *acpi_spi_find_controller_by_adev(struct acpi_device *adev)
4154 {
4155         struct device *dev;
4156
4157         dev = class_find_device(&spi_master_class, NULL, adev,
4158                                 spi_acpi_controller_match);
4159         if (!dev && IS_ENABLED(CONFIG_SPI_SLAVE))
4160                 dev = class_find_device(&spi_slave_class, NULL, adev,
4161                                         spi_acpi_controller_match);
4162         if (!dev)
4163                 return NULL;
4164
4165         return container_of(dev, struct spi_controller, dev);
4166 }
4167
4168 static struct spi_device *acpi_spi_find_device_by_adev(struct acpi_device *adev)
4169 {
4170         struct device *dev;
4171
4172         dev = bus_find_device_by_acpi_dev(&spi_bus_type, adev);
4173         return to_spi_device(dev);
4174 }
4175
4176 static int acpi_spi_notify(struct notifier_block *nb, unsigned long value,
4177                            void *arg)
4178 {
4179         struct acpi_device *adev = arg;
4180         struct spi_controller *ctlr;
4181         struct spi_device *spi;
4182
4183         switch (value) {
4184         case ACPI_RECONFIG_DEVICE_ADD:
4185                 ctlr = acpi_spi_find_controller_by_adev(adev->parent);
4186                 if (!ctlr)
4187                         break;
4188
4189                 acpi_register_spi_device(ctlr, adev);
4190                 put_device(&ctlr->dev);
4191                 break;
4192         case ACPI_RECONFIG_DEVICE_REMOVE:
4193                 if (!acpi_device_enumerated(adev))
4194                         break;
4195
4196                 spi = acpi_spi_find_device_by_adev(adev);
4197                 if (!spi)
4198                         break;
4199
4200                 spi_unregister_device(spi);
4201                 put_device(&spi->dev);
4202                 break;
4203         }
4204
4205         return NOTIFY_OK;
4206 }
4207
4208 static struct notifier_block spi_acpi_notifier = {
4209         .notifier_call = acpi_spi_notify,
4210 };
4211 #else
4212 extern struct notifier_block spi_acpi_notifier;
4213 #endif
4214
4215 static int __init spi_init(void)
4216 {
4217         int     status;
4218
4219         buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
4220         if (!buf) {
4221                 status = -ENOMEM;
4222                 goto err0;
4223         }
4224
4225         status = bus_register(&spi_bus_type);
4226         if (status < 0)
4227                 goto err1;
4228
4229         status = class_register(&spi_master_class);
4230         if (status < 0)
4231                 goto err2;
4232
4233         if (IS_ENABLED(CONFIG_SPI_SLAVE)) {
4234                 status = class_register(&spi_slave_class);
4235                 if (status < 0)
4236                         goto err3;
4237         }
4238
4239         if (IS_ENABLED(CONFIG_OF_DYNAMIC))
4240                 WARN_ON(of_reconfig_notifier_register(&spi_of_notifier));
4241         if (IS_ENABLED(CONFIG_ACPI))
4242                 WARN_ON(acpi_reconfig_notifier_register(&spi_acpi_notifier));
4243
4244         return 0;
4245
4246 err3:
4247         class_unregister(&spi_master_class);
4248 err2:
4249         bus_unregister(&spi_bus_type);
4250 err1:
4251         kfree(buf);
4252         buf = NULL;
4253 err0:
4254         return status;
4255 }
4256
4257 /* board_info is normally registered in arch_initcall(),
4258  * but even essential drivers wait till later
4259  *
4260  * REVISIT only boardinfo really needs static linking. the rest (device and
4261  * driver registration) _could_ be dynamically linked (modular) ... costs
4262  * include needing to have boardinfo data structures be much more public.
4263  */
4264 postcore_initcall(spi_init);