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->properties) {
 680                 status = device_add_properties(&proxy->dev, chip->properties);
 681                 if (status) {
 682                         dev_err(&ctlr->dev,
 683                                 "failed to add properties to '%s': %d\n",
 684                                 chip->modalias, status);
 685                         goto err_dev_put;
 686                 }
 687         }
 688
 689         status = spi_add_device(proxy);
 690         if (status < 0)
 691                 goto err_remove_props;
 692
 693         return proxy;
 694
 695 err_remove_props:
 696         if (chip->properties)
 697                 device_remove_properties(&proxy->dev);
 698 err_dev_put:
 699         spi_dev_put(proxy);
 700         return NULL;
 701 }
 702 EXPORT_SYMBOL_GPL(spi_new_device);
 703
 704 /**
 705  * spi_unregister_device - unregister a single SPI device
 706  * @spi: spi_device to unregister
 707  *
 708  * Start making the passed SPI device vanish. Normally this would be handled
 709  * by spi_unregister_controller().
 710  */
 711 void spi_unregister_device(struct spi_device *spi)
 712 {
 713         if (!spi)
 714                 return;
 715
 716         if (spi->dev.of_node) {
 717                 of_node_clear_flag(spi->dev.of_node, OF_POPULATED);
 718                 of_node_put(spi->dev.of_node);
 719         }
 720         if (ACPI_COMPANION(&spi->dev))
 721                 acpi_device_clear_enumerated(ACPI_COMPANION(&spi->dev));
 722         device_unregister(&spi->dev);
 723 }
 724 EXPORT_SYMBOL_GPL(spi_unregister_device);
 725
 726 static void spi_match_controller_to_boardinfo(struct spi_controller *ctlr,
 727                                               struct spi_board_info *bi)
 728 {
 729         struct spi_device *dev;
 730
 731         if (ctlr->bus_num != bi->bus_num)
 732                 return;
 733
 734         dev = spi_new_device(ctlr, bi);
 735         if (!dev)
 736                 dev_err(ctlr->dev.parent, "can't create new device for %s\n",
 737                         bi->modalias);
 738 }
 739
 740 /**
 741  * spi_register_board_info - register SPI devices for a given board
 742  * @info: array of chip descriptors
 743  * @n: how many descriptors are provided
 744  * Context: can sleep
 745  *
 746  * Board-specific early init code calls this (probably during arch_initcall)
 747  * with segments of the SPI device table.  Any device nodes are created later,
 748  * after the relevant parent SPI controller (bus_num) is defined.  We keep
 749  * this table of devices forever, so that reloading a controller driver will
 750  * not make Linux forget about these hard-wired devices.
 751  *
 752  * Other code can also call this, e.g. a particular add-on board might provide
 753  * SPI devices through its expansion connector, so code initializing that board
 754  * would naturally declare its SPI devices.
 755  *
 756  * The board info passed can safely be __initdata ... but be careful of
 757  * any embedded pointers (platform_data, etc), they're copied as-is.
 758  * Device properties are deep-copied though.
 759  *
 760  * Return: zero on success, else a negative error code.
 761  */
 762 int spi_register_board_info(struct spi_board_info const *info, unsigned n)
 763 {
 764         struct boardinfo *bi;
 765         int i;
 766
 767         if (!n)
 768                 return 0;
 769
 770         bi = kcalloc(n, sizeof(*bi), GFP_KERNEL);
 771         if (!bi)
 772                 return -ENOMEM;
 773
 774         for (i = 0; i < n; i++, bi++, info++) {
 775                 struct spi_controller *ctlr;
 776
 777                 memcpy(&bi->board_info, info, sizeof(*info));
 778                 if (info->properties) {
 779                         bi->board_info.properties =
 780                                         property_entries_dup(info->properties);
 781                         if (IS_ERR(bi->board_info.properties))
 782                                 return PTR_ERR(bi->board_info.properties);
 783                 }
 784
 785                 mutex_lock(&board_lock);
 786                 list_add_tail(&bi->list, &board_list);
 787                 list_for_each_entry(ctlr, &spi_controller_list, list)
 788                         spi_match_controller_to_boardinfo(ctlr,
 789                                                           &bi->board_info);
 790                 mutex_unlock(&board_lock);
 791         }
 792
 793         return 0;
 794 }
 795
 796 /*-------------------------------------------------------------------------*/
 797
 798 static void spi_set_cs(struct spi_device *spi, bool enable)
 799 {
 800         bool enable1 = enable;
 801
 802         /*
 803          * Avoid calling into the driver (or doing delays) if the chip select
 804          * isn't actually changing from the last time this was called.
 805          */
 806         if ((spi->controller->last_cs_enable == enable) &&
 807             (spi->controller->last_cs_mode_high == (spi->mode & SPI_CS_HIGH)))
 808                 return;
 809
 810         spi->controller->last_cs_enable = enable;
 811         spi->controller->last_cs_mode_high = spi->mode & SPI_CS_HIGH;
 812
 813         if (!spi->controller->set_cs_timing) {
 814                 if (enable1)
 815                         spi_delay_exec(&spi->controller->cs_setup, NULL);
 816                 else
 817                         spi_delay_exec(&spi->controller->cs_hold, NULL);
 818         }
 819
 820         if (spi->mode & SPI_CS_HIGH)
 821                 enable = !enable;
 822
 823         if (spi->cs_gpiod || gpio_is_valid(spi->cs_gpio)) {
 824                 if (!(spi->mode & SPI_NO_CS)) {
 825                         if (spi->cs_gpiod)
 826                                 /* polarity handled by gpiolib */
 827                                 gpiod_set_value_cansleep(spi->cs_gpiod,
 828                                                          enable1);
 829                         else
 830                                 /*
 831                                  * invert the enable line, as active low is
 832                                  * default for SPI.
 833                                  */
 834                                 gpio_set_value_cansleep(spi->cs_gpio, !enable);
 835                 }
 836                 /* Some SPI masters need both GPIO CS & slave_select */
 837                 if ((spi->controller->flags & SPI_MASTER_GPIO_SS) &&
 838                     spi->controller->set_cs)
 839                         spi->controller->set_cs(spi, !enable);
 840         } else if (spi->controller->set_cs) {
 841                 spi->controller->set_cs(spi, !enable);
 842         }
 843
 844         if (!spi->controller->set_cs_timing) {
 845                 if (!enable1)
 846                         spi_delay_exec(&spi->controller->cs_inactive, NULL);
 847         }
 848 }
 849
 850 #ifdef CONFIG_HAS_DMA
 851 int spi_map_buf(struct spi_controller *ctlr, struct device *dev,
 852                 struct sg_table *sgt, void *buf, size_t len,
 853                 enum dma_data_direction dir)
 854 {
 855         const bool vmalloced_buf = is_vmalloc_addr(buf);
 856         unsigned int max_seg_size = dma_get_max_seg_size(dev);
 857 #ifdef CONFIG_HIGHMEM
 858         const bool kmap_buf = ((unsigned long)buf >= PKMAP_BASE &&
 859                                 (unsigned long)buf < (PKMAP_BASE +
 860                                         (LAST_PKMAP * PAGE_SIZE)));
 861 #else
 862         const bool kmap_buf = false;
 863 #endif
 864         int desc_len;
 865         int sgs;
 866         struct page *vm_page;
 867         struct scatterlist *sg;
 868         void *sg_buf;
 869         size_t min;
 870         int i, ret;
 871
 872         if (vmalloced_buf || kmap_buf) {
 873                 desc_len = min_t(int, max_seg_size, PAGE_SIZE);
 874                 sgs = DIV_ROUND_UP(len + offset_in_page(buf), desc_len);
 875         } else if (virt_addr_valid(buf)) {
 876                 desc_len = min_t(int, max_seg_size, ctlr->max_dma_len);
 877                 sgs = DIV_ROUND_UP(len, desc_len);
 878         } else {
 879                 return -EINVAL;
 880         }
 881
 882         ret = sg_alloc_table(sgt, sgs, GFP_KERNEL);
 883         if (ret != 0)
 884                 return ret;
 885
 886         sg = &sgt->sgl[0];
 887         for (i = 0; i < sgs; i++) {
 888
 889                 if (vmalloced_buf || kmap_buf) {
 890                         /*
 891                          * Next scatterlist entry size is the minimum between
 892                          * the desc_len and the remaining buffer length that
 893                          * fits in a page.
 894                          */
 895                         min = min_t(size_t, desc_len,
 896                                     min_t(size_t, len,
 897                                           PAGE_SIZE - offset_in_page(buf)));
 898                         if (vmalloced_buf)
 899                                 vm_page = vmalloc_to_page(buf);
 900                         else
 901                                 vm_page = kmap_to_page(buf);
 902                         if (!vm_page) {
 903                                 sg_free_table(sgt);
 904                                 return -ENOMEM;
 905                         }
 906                         sg_set_page(sg, vm_page,
 907                                     min, offset_in_page(buf));
 908                 } else {
 909                         min = min_t(size_t, len, desc_len);
 910                         sg_buf = buf;
 911                         sg_set_buf(sg, sg_buf, min);
 912                 }
 913
 914                 buf += min;
 915                 len -= min;
 916                 sg = sg_next(sg);
 917         }
 918
 919         ret = dma_map_sg(dev, sgt->sgl, sgt->nents, dir);
 920         if (!ret)
 921                 ret = -ENOMEM;
 922         if (ret < 0) {
 923                 sg_free_table(sgt);
 924                 return ret;
 925         }
 926
 927         sgt->nents = ret;
 928
 929         return 0;
 930 }
 931
 932 void spi_unmap_buf(struct spi_controller *ctlr, struct device *dev,
 933                    struct sg_table *sgt, enum dma_data_direction dir)
 934 {
 935         if (sgt->orig_nents) {
 936                 dma_unmap_sg(dev, sgt->sgl, sgt->orig_nents, dir);
 937                 sg_free_table(sgt);
 938         }
 939 }
 940
 941 static int __spi_map_msg(struct spi_controller *ctlr, struct spi_message *msg)
 942 {
 943         struct device *tx_dev, *rx_dev;
 944         struct spi_transfer *xfer;
 945         int ret;
 946
 947         if (!ctlr->can_dma)
 948                 return 0;
 949
 950         if (ctlr->dma_tx)
 951                 tx_dev = ctlr->dma_tx->device->dev;
 952         else
 953                 tx_dev = ctlr->dev.parent;
 954
 955         if (ctlr->dma_rx)
 956                 rx_dev = ctlr->dma_rx->device->dev;
 957         else
 958                 rx_dev = ctlr->dev.parent;
 959
 960         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 961                 if (!ctlr->can_dma(ctlr, msg->spi, xfer))
 962                         continue;
 963
 964                 if (xfer->tx_buf != NULL) {
 965                         ret = spi_map_buf(ctlr, tx_dev, &xfer->tx_sg,
 966                                           (void *)xfer->tx_buf, xfer->len,
 967                                           DMA_TO_DEVICE);
 968                         if (ret != 0)
 969                                 return ret;
 970                 }
 971
 972                 if (xfer->rx_buf != NULL) {
 973                         ret = spi_map_buf(ctlr, rx_dev, &xfer->rx_sg,
 974                                           xfer->rx_buf, xfer->len,
 975                                           DMA_FROM_DEVICE);
 976                         if (ret != 0) {
 977                                 spi_unmap_buf(ctlr, tx_dev, &xfer->tx_sg,
 978                                               DMA_TO_DEVICE);
 979                                 return ret;
 980                         }
 981                 }
 982         }
 983
 984         ctlr->cur_msg_mapped = true;
 985
 986         return 0;
 987 }
 988
 989 static int __spi_unmap_msg(struct spi_controller *ctlr, struct spi_message *msg)
 990 {
 991         struct spi_transfer *xfer;
 992         struct device *tx_dev, *rx_dev;
 993
 994         if (!ctlr->cur_msg_mapped || !ctlr->can_dma)
 995                 return 0;
 996
 997         if (ctlr->dma_tx)
 998                 tx_dev = ctlr->dma_tx->device->dev;
 999         else
1000                 tx_dev = ctlr->dev.parent;
1001
1002         if (ctlr->dma_rx)
1003                 rx_dev = ctlr->dma_rx->device->dev;
1004         else
1005                 rx_dev = ctlr->dev.parent;
1006
1007         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1008                 if (!ctlr->can_dma(ctlr, msg->spi, xfer))
1009                         continue;
1010
1011                 spi_unmap_buf(ctlr, rx_dev, &xfer->rx_sg, DMA_FROM_DEVICE);
1012                 spi_unmap_buf(ctlr, tx_dev, &xfer->tx_sg, DMA_TO_DEVICE);
1013         }
1014
1015         ctlr->cur_msg_mapped = false;
1016
1017         return 0;
1018 }
1019 #else /* !CONFIG_HAS_DMA */
1020 static inline int __spi_map_msg(struct spi_controller *ctlr,
1021                                 struct spi_message *msg)
1022 {
1023         return 0;
1024 }
1025
1026 static inline int __spi_unmap_msg(struct spi_controller *ctlr,
1027                                   struct spi_message *msg)
1028 {
1029         return 0;
1030 }
1031 #endif /* !CONFIG_HAS_DMA */
1032
1033 static inline int spi_unmap_msg(struct spi_controller *ctlr,
1034                                 struct spi_message *msg)
1035 {
1036         struct spi_transfer *xfer;
1037
1038         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1039                 /*
1040                  * Restore the original value of tx_buf or rx_buf if they are
1041                  * NULL.
1042                  */
1043                 if (xfer->tx_buf == ctlr->dummy_tx)
1044                         xfer->tx_buf = NULL;
1045                 if (xfer->rx_buf == ctlr->dummy_rx)
1046                         xfer->rx_buf = NULL;
1047         }
1048
1049         return __spi_unmap_msg(ctlr, msg);
1050 }
1051
1052 static int spi_map_msg(struct spi_controller *ctlr, struct spi_message *msg)
1053 {
1054         struct spi_transfer *xfer;
1055         void *tmp;
1056         unsigned int max_tx, max_rx;
1057
1058         if ((ctlr->flags & (SPI_CONTROLLER_MUST_RX | SPI_CONTROLLER_MUST_TX))
1059                 && !(msg->spi->mode & SPI_3WIRE)) {
1060                 max_tx = 0;
1061                 max_rx = 0;
1062
1063                 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1064                         if ((ctlr->flags & SPI_CONTROLLER_MUST_TX) &&
1065                             !xfer->tx_buf)
1066                                 max_tx = max(xfer->len, max_tx);
1067                         if ((ctlr->flags & SPI_CONTROLLER_MUST_RX) &&
1068                             !xfer->rx_buf)
1069                                 max_rx = max(xfer->len, max_rx);
1070                 }
1071
1072                 if (max_tx) {
1073                         tmp = krealloc(ctlr->dummy_tx, max_tx,
1074                                        GFP_KERNEL | GFP_DMA);
1075                         if (!tmp)
1076                                 return -ENOMEM;
1077                         ctlr->dummy_tx = tmp;
1078                         memset(tmp, 0, max_tx);
1079                 }
1080
1081                 if (max_rx) {
1082                         tmp = krealloc(ctlr->dummy_rx, max_rx,
1083                                        GFP_KERNEL | GFP_DMA);
1084                         if (!tmp)
1085                                 return -ENOMEM;
1086                         ctlr->dummy_rx = tmp;
1087                 }
1088
1089                 if (max_tx || max_rx) {
1090                         list_for_each_entry(xfer, &msg->transfers,
1091                                             transfer_list) {
1092                                 if (!xfer->len)
1093                                         continue;
1094                                 if (!xfer->tx_buf)
1095                                         xfer->tx_buf = ctlr->dummy_tx;
1096                                 if (!xfer->rx_buf)
1097                                         xfer->rx_buf = ctlr->dummy_rx;
1098                         }
1099                 }
1100         }
1101
1102         return __spi_map_msg(ctlr, msg);
1103 }
1104
1105 static int spi_transfer_wait(struct spi_controller *ctlr,
1106                              struct spi_message *msg,
1107                              struct spi_transfer *xfer)
1108 {
1109         struct spi_statistics *statm = &ctlr->statistics;
1110         struct spi_statistics *stats = &msg->spi->statistics;
1111         unsigned long long ms;
1112
1113         if (spi_controller_is_slave(ctlr)) {
1114                 if (wait_for_completion_interruptible(&ctlr->xfer_completion)) {
1115                         dev_dbg(&msg->spi->dev, "SPI transfer interrupted\n");
1116                         return -EINTR;
1117                 }
1118         } else {
1119                 ms = 8LL * 1000LL * xfer->len;
1120                 do_div(ms, xfer->speed_hz);
1121                 ms += ms + 200; /* some tolerance */
1122
1123                 if (ms > UINT_MAX)
1124                         ms = UINT_MAX;
1125
1126                 ms = wait_for_completion_timeout(&ctlr->xfer_completion,
1127                                                  msecs_to_jiffies(ms));
1128
1129                 if (ms == 0) {
1130                         SPI_STATISTICS_INCREMENT_FIELD(statm, timedout);
1131                         SPI_STATISTICS_INCREMENT_FIELD(stats, timedout);
1132                         dev_err(&msg->spi->dev,
1133                                 "SPI transfer timed out\n");
1134                         return -ETIMEDOUT;
1135                 }
1136         }
1137
1138         return 0;
1139 }
1140
1141 static void _spi_transfer_delay_ns(u32 ns)
1142 {
1143         if (!ns)
1144                 return;
1145         if (ns <= 1000) {
1146                 ndelay(ns);
1147         } else {
1148                 u32 us = DIV_ROUND_UP(ns, 1000);
1149
1150                 if (us <= 10)
1151                         udelay(us);
1152                 else
1153                         usleep_range(us, us + DIV_ROUND_UP(us, 10));
1154         }
1155 }
1156
1157 int spi_delay_to_ns(struct spi_delay *_delay, struct spi_transfer *xfer)
1158 {
1159         u32 delay = _delay->value;
1160         u32 unit = _delay->unit;
1161         u32 hz;
1162
1163         if (!delay)
1164                 return 0;
1165
1166         switch (unit) {
1167         case SPI_DELAY_UNIT_USECS:
1168                 delay *= 1000;
1169                 break;
1170         case SPI_DELAY_UNIT_NSECS: /* nothing to do here */
1171                 break;
1172         case SPI_DELAY_UNIT_SCK:
1173                 /* clock cycles need to be obtained from spi_transfer */
1174                 if (!xfer)
1175                         return -EINVAL;
1176                 /* if there is no effective speed know, then approximate
1177                  * by underestimating with half the requested hz
1178                  */
1179                 hz = xfer->effective_speed_hz ?: xfer->speed_hz / 2;
1180                 if (!hz)
1181                         return -EINVAL;
1182                 delay *= DIV_ROUND_UP(1000000000, hz);
1183                 break;
1184         default:
1185                 return -EINVAL;
1186         }
1187
1188         return delay;
1189 }
1190 EXPORT_SYMBOL_GPL(spi_delay_to_ns);
1191
1192 int spi_delay_exec(struct spi_delay *_delay, struct spi_transfer *xfer)
1193 {
1194         int delay;
1195
1196         might_sleep();
1197
1198         if (!_delay)
1199                 return -EINVAL;
1200
1201         delay = spi_delay_to_ns(_delay, xfer);
1202         if (delay < 0)
1203                 return delay;
1204
1205         _spi_transfer_delay_ns(delay);
1206
1207         return 0;
1208 }
1209 EXPORT_SYMBOL_GPL(spi_delay_exec);
1210
1211 static void _spi_transfer_cs_change_delay(struct spi_message *msg,
1212                                           struct spi_transfer *xfer)
1213 {
1214         u32 delay = xfer->cs_change_delay.value;
1215         u32 unit = xfer->cs_change_delay.unit;
1216         int ret;
1217
1218         /* return early on "fast" mode - for everything but USECS */
1219         if (!delay) {
1220                 if (unit == SPI_DELAY_UNIT_USECS)
1221                         _spi_transfer_delay_ns(10000);
1222                 return;
1223         }
1224
1225         ret = spi_delay_exec(&xfer->cs_change_delay, xfer);
1226         if (ret) {
1227                 dev_err_once(&msg->spi->dev,
1228                              "Use of unsupported delay unit %i, using default of 10us\n",
1229                              unit);
1230                 _spi_transfer_delay_ns(10000);
1231         }
1232 }
1233
1234 /*
1235  * spi_transfer_one_message - Default implementation of transfer_one_message()
1236  *
1237  * This is a standard implementation of transfer_one_message() for
1238  * drivers which implement a transfer_one() operation.  It provides
1239  * standard handling of delays and chip select management.
1240  */
1241 static int spi_transfer_one_message(struct spi_controller *ctlr,
1242                                     struct spi_message *msg)
1243 {
1244         struct spi_transfer *xfer;
1245         bool keep_cs = false;
1246         int ret = 0;
1247         struct spi_statistics *statm = &ctlr->statistics;
1248         struct spi_statistics *stats = &msg->spi->statistics;
1249
1250         spi_set_cs(msg->spi, true);
1251
1252         SPI_STATISTICS_INCREMENT_FIELD(statm, messages);
1253         SPI_STATISTICS_INCREMENT_FIELD(stats, messages);
1254
1255         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1256                 trace_spi_transfer_start(msg, xfer);
1257
1258                 spi_statistics_add_transfer_stats(statm, xfer, ctlr);
1259                 spi_statistics_add_transfer_stats(stats, xfer, ctlr);
1260
1261                 if (!ctlr->ptp_sts_supported) {
1262                         xfer->ptp_sts_word_pre = 0;
1263                         ptp_read_system_prets(xfer->ptp_sts);
1264                 }
1265
1266                 if (xfer->tx_buf || xfer->rx_buf) {
1267                         reinit_completion(&ctlr->xfer_completion);
1268
1269 fallback_pio:
1270                         ret = ctlr->transfer_one(ctlr, msg->spi, xfer);
1271                         if (ret < 0) {
1272                                 if (ctlr->cur_msg_mapped &&
1273                                    (xfer->error & SPI_TRANS_FAIL_NO_START)) {
1274                                         __spi_unmap_msg(ctlr, msg);
1275                                         ctlr->fallback = true;
1276                                         xfer->error &= ~SPI_TRANS_FAIL_NO_START;
1277                                         goto fallback_pio;
1278                                 }
1279
1280                                 SPI_STATISTICS_INCREMENT_FIELD(statm,
1281                                                                errors);
1282                                 SPI_STATISTICS_INCREMENT_FIELD(stats,
1283                                                                errors);
1284                                 dev_err(&msg->spi->dev,
1285                                         "SPI transfer failed: %d\n", ret);
1286                                 goto out;
1287                         }
1288
1289                         if (ret > 0) {
1290                                 ret = spi_transfer_wait(ctlr, msg, xfer);
1291                                 if (ret < 0)
1292                                         msg->status = ret;
1293                         }
1294                 } else {
1295                         if (xfer->len)
1296                                 dev_err(&msg->spi->dev,
1297                                         "Bufferless transfer has length %u\n",
1298                                         xfer->len);
1299                 }
1300
1301                 if (!ctlr->ptp_sts_supported) {
1302                         ptp_read_system_postts(xfer->ptp_sts);
1303                         xfer->ptp_sts_word_post = xfer->len;
1304                 }
1305
1306                 trace_spi_transfer_stop(msg, xfer);
1307
1308                 if (msg->status != -EINPROGRESS)
1309                         goto out;
1310
1311                 spi_transfer_delay_exec(xfer);
1312
1313                 if (xfer->cs_change) {
1314                         if (list_is_last(&xfer->transfer_list,
1315                                          &msg->transfers)) {
1316                                 keep_cs = true;
1317                         } else {
1318                                 spi_set_cs(msg->spi, false);
1319                                 _spi_transfer_cs_change_delay(msg, xfer);
1320                                 spi_set_cs(msg->spi, true);
1321                         }
1322                 }
1323
1324                 msg->actual_length += xfer->len;
1325         }
1326
1327 out:
1328         if (ret != 0 || !keep_cs)
1329                 spi_set_cs(msg->spi, false);
1330
1331         if (msg->status == -EINPROGRESS)
1332                 msg->status = ret;
1333
1334         if (msg->status && ctlr->handle_err)
1335                 ctlr->handle_err(ctlr, msg);
1336
1337         spi_finalize_current_message(ctlr);
1338
1339         return ret;
1340 }
1341
1342 /**
1343  * spi_finalize_current_transfer - report completion of a transfer
1344  * @ctlr: the controller reporting completion
1345  *
1346  * Called by SPI drivers using the core transfer_one_message()
1347  * implementation to notify it that the current interrupt driven
1348  * transfer has finished and the next one may be scheduled.
1349  */
1350 void spi_finalize_current_transfer(struct spi_controller *ctlr)
1351 {
1352         complete(&ctlr->xfer_completion);
1353 }
1354 EXPORT_SYMBOL_GPL(spi_finalize_current_transfer);
1355
1356 static void spi_idle_runtime_pm(struct spi_controller *ctlr)
1357 {
1358         if (ctlr->auto_runtime_pm) {
1359                 pm_runtime_mark_last_busy(ctlr->dev.parent);
1360                 pm_runtime_put_autosuspend(ctlr->dev.parent);
1361         }
1362 }
1363
1364 /**
1365  * __spi_pump_messages - function which processes spi message queue
1366  * @ctlr: controller to process queue for
1367  * @in_kthread: true if we are in the context of the message pump thread
1368  *
1369  * This function checks if there is any spi message in the queue that
1370  * needs processing and if so call out to the driver to initialize hardware
1371  * and transfer each message.
1372  *
1373  * Note that it is called both from the kthread itself and also from
1374  * inside spi_sync(); the queue extraction handling at the top of the
1375  * function should deal with this safely.
1376  */
1377 static void __spi_pump_messages(struct spi_controller *ctlr, bool in_kthread)
1378 {
1379         struct spi_transfer *xfer;
1380         struct spi_message *msg;
1381         bool was_busy = false;
1382         unsigned long flags;
1383         int ret;
1384
1385         /* Lock queue */
1386         spin_lock_irqsave(&ctlr->queue_lock, flags);
1387
1388         /* Make sure we are not already running a message */
1389         if (ctlr->cur_msg) {
1390                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1391                 return;
1392         }
1393
1394         /* If another context is idling the device then defer */
1395         if (ctlr->idling) {
1396                 kthread_queue_work(ctlr->kworker, &ctlr->pump_messages);
1397                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1398                 return;
1399         }
1400
1401         /* Check if the queue is idle */
1402         if (list_empty(&ctlr->queue) || !ctlr->running) {
1403                 if (!ctlr->busy) {
1404                         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1405                         return;
1406                 }
1407
1408                 /* Defer any non-atomic teardown to the thread */
1409                 if (!in_kthread) {
1410                         if (!ctlr->dummy_rx && !ctlr->dummy_tx &&
1411                             !ctlr->unprepare_transfer_hardware) {
1412                                 spi_idle_runtime_pm(ctlr);
1413                                 ctlr->busy = false;
1414                                 trace_spi_controller_idle(ctlr);
1415                         } else {
1416                                 kthread_queue_work(ctlr->kworker,
1417                                                    &ctlr->pump_messages);
1418                         }
1419                         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1420                         return;
1421                 }
1422
1423                 ctlr->busy = false;
1424                 ctlr->idling = true;
1425                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1426
1427                 kfree(ctlr->dummy_rx);
1428                 ctlr->dummy_rx = NULL;
1429                 kfree(ctlr->dummy_tx);
1430                 ctlr->dummy_tx = NULL;
1431                 if (ctlr->unprepare_transfer_hardware &&
1432                     ctlr->unprepare_transfer_hardware(ctlr))
1433                         dev_err(&ctlr->dev,
1434                                 "failed to unprepare transfer hardware\n");
1435                 spi_idle_runtime_pm(ctlr);
1436                 trace_spi_controller_idle(ctlr);
1437
1438                 spin_lock_irqsave(&ctlr->queue_lock, flags);
1439                 ctlr->idling = false;
1440                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1441                 return;
1442         }
1443
1444         /* Extract head of queue */
1445         msg = list_first_entry(&ctlr->queue, struct spi_message, queue);
1446         ctlr->cur_msg = msg;
1447
1448         list_del_init(&msg->queue);
1449         if (ctlr->busy)
1450                 was_busy = true;
1451         else
1452                 ctlr->busy = true;
1453         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1454
1455         mutex_lock(&ctlr->io_mutex);
1456
1457         if (!was_busy && ctlr->auto_runtime_pm) {
1458                 ret = pm_runtime_get_sync(ctlr->dev.parent);
1459                 if (ret < 0) {
1460                         pm_runtime_put_noidle(ctlr->dev.parent);
1461                         dev_err(&ctlr->dev, "Failed to power device: %d\n",
1462                                 ret);
1463                         mutex_unlock(&ctlr->io_mutex);
1464                         return;
1465                 }
1466         }
1467
1468         if (!was_busy)
1469                 trace_spi_controller_busy(ctlr);
1470
1471         if (!was_busy && ctlr->prepare_transfer_hardware) {
1472                 ret = ctlr->prepare_transfer_hardware(ctlr);
1473                 if (ret) {
1474                         dev_err(&ctlr->dev,
1475                                 "failed to prepare transfer hardware: %d\n",
1476                                 ret);
1477
1478                         if (ctlr->auto_runtime_pm)
1479                                 pm_runtime_put(ctlr->dev.parent);
1480
1481                         msg->status = ret;
1482                         spi_finalize_current_message(ctlr);
1483
1484                         mutex_unlock(&ctlr->io_mutex);
1485                         return;
1486                 }
1487         }
1488
1489         trace_spi_message_start(msg);
1490
1491         if (ctlr->prepare_message) {
1492                 ret = ctlr->prepare_message(ctlr, msg);
1493                 if (ret) {
1494                         dev_err(&ctlr->dev, "failed to prepare message: %d\n",
1495                                 ret);
1496                         msg->status = ret;
1497                         spi_finalize_current_message(ctlr);
1498                         goto out;
1499                 }
1500                 ctlr->cur_msg_prepared = true;
1501         }
1502
1503         ret = spi_map_msg(ctlr, msg);
1504         if (ret) {
1505                 msg->status = ret;
1506                 spi_finalize_current_message(ctlr);
1507                 goto out;
1508         }
1509
1510         if (!ctlr->ptp_sts_supported && !ctlr->transfer_one) {
1511                 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1512                         xfer->ptp_sts_word_pre = 0;
1513                         ptp_read_system_prets(xfer->ptp_sts);
1514                 }
1515         }
1516
1517         ret = ctlr->transfer_one_message(ctlr, msg);
1518         if (ret) {
1519                 dev_err(&ctlr->dev,
1520                         "failed to transfer one message from queue\n");
1521                 goto out;
1522         }
1523
1524 out:
1525         mutex_unlock(&ctlr->io_mutex);
1526
1527         /* Prod the scheduler in case transfer_one() was busy waiting */
1528         if (!ret)
1529                 cond_resched();
1530 }
1531
1532 /**
1533  * spi_pump_messages - kthread work function which processes spi message queue
1534  * @work: pointer to kthread work struct contained in the controller struct
1535  */
1536 static void spi_pump_messages(struct kthread_work *work)
1537 {
1538         struct spi_controller *ctlr =
1539                 container_of(work, struct spi_controller, pump_messages);
1540
1541         __spi_pump_messages(ctlr, true);
1542 }
1543
1544 /**
1545  * spi_take_timestamp_pre - helper for drivers to collect the beginning of the
1546  *                          TX timestamp for the requested byte from the SPI
1547  *                          transfer. The frequency with which this function
1548  *                          must be called (once per word, once for the whole
1549  *                          transfer, once per batch of words etc) is arbitrary
1550  *                          as long as the @tx buffer offset is greater than or
1551  *                          equal to the requested byte at the time of the
1552  *                          call. The timestamp is only taken once, at the
1553  *                          first such call. It is assumed that the driver
1554  *                          advances its @tx buffer pointer monotonically.
1555  * @ctlr: Pointer to the spi_controller structure of the driver
1556  * @xfer: Pointer to the transfer being timestamped
1557  * @progress: How many words (not bytes) have been transferred so far
1558  * @irqs_off: If true, will disable IRQs and preemption for the duration of the
1559  *            transfer, for less jitter in time measurement. Only compatible
1560  *            with PIO drivers. If true, must follow up with
1561  *            spi_take_timestamp_post or otherwise system will crash.
1562  *            WARNING: for fully predictable results, the CPU frequency must
1563  *            also be under control (governor).
1564  */
1565 void spi_take_timestamp_pre(struct spi_controller *ctlr,
1566                             struct spi_transfer *xfer,
1567                             size_t progress, bool irqs_off)
1568 {
1569         if (!xfer->ptp_sts)
1570                 return;
1571
1572         if (xfer->timestamped)
1573                 return;
1574
1575         if (progress > xfer->ptp_sts_word_pre)
1576                 return;
1577
1578         /* Capture the resolution of the timestamp */
1579         xfer->ptp_sts_word_pre = progress;
1580
1581         if (irqs_off) {
1582                 local_irq_save(ctlr->irq_flags);
1583                 preempt_disable();
1584         }
1585
1586         ptp_read_system_prets(xfer->ptp_sts);
1587 }
1588 EXPORT_SYMBOL_GPL(spi_take_timestamp_pre);
1589
1590 /**
1591  * spi_take_timestamp_post - helper for drivers to collect the end of the
1592  *                           TX timestamp for the requested byte from the SPI
1593  *                           transfer. Can be called with an arbitrary
1594  *                           frequency: only the first call where @tx exceeds
1595  *                           or is equal to the requested word will be
1596  *                           timestamped.
1597  * @ctlr: Pointer to the spi_controller structure of the driver
1598  * @xfer: Pointer to the transfer being timestamped
1599  * @progress: How many words (not bytes) have been transferred so far
1600  * @irqs_off: If true, will re-enable IRQs and preemption for the local CPU.
1601  */
1602 void spi_take_timestamp_post(struct spi_controller *ctlr,
1603                              struct spi_transfer *xfer,
1604                              size_t progress, bool irqs_off)
1605 {
1606         if (!xfer->ptp_sts)
1607                 return;
1608
1609         if (xfer->timestamped)
1610                 return;
1611
1612         if (progress < xfer->ptp_sts_word_post)
1613                 return;
1614
1615         ptp_read_system_postts(xfer->ptp_sts);
1616
1617         if (irqs_off) {
1618                 local_irq_restore(ctlr->irq_flags);
1619                 preempt_enable();
1620         }
1621
1622         /* Capture the resolution of the timestamp */
1623         xfer->ptp_sts_word_post = progress;
1624
1625         xfer->timestamped = true;
1626 }
1627 EXPORT_SYMBOL_GPL(spi_take_timestamp_post);
1628
1629 /**
1630  * spi_set_thread_rt - set the controller to pump at realtime priority
1631  * @ctlr: controller to boost priority of
1632  *
1633  * This can be called because the controller requested realtime priority
1634  * (by setting the ->rt value before calling spi_register_controller()) or
1635  * because a device on the bus said that its transfers needed realtime
1636  * priority.
1637  *
1638  * NOTE: at the moment if any device on a bus says it needs realtime then
1639  * the thread will be at realtime priority for all transfers on that
1640  * controller.  If this eventually becomes a problem we may see if we can
1641  * find a way to boost the priority only temporarily during relevant
1642  * transfers.
1643  */
1644 static void spi_set_thread_rt(struct spi_controller *ctlr)
1645 {
1646         dev_info(&ctlr->dev,
1647                 "will run message pump with realtime priority\n");
1648         sched_set_fifo(ctlr->kworker->task);
1649 }
1650
1651 static int spi_init_queue(struct spi_controller *ctlr)
1652 {
1653         ctlr->running = false;
1654         ctlr->busy = false;
1655
1656         ctlr->kworker = kthread_create_worker(0, dev_name(&ctlr->dev));
1657         if (IS_ERR(ctlr->kworker)) {
1658                 dev_err(&ctlr->dev, "failed to create message pump kworker\n");
1659                 return PTR_ERR(ctlr->kworker);
1660         }
1661
1662         kthread_init_work(&ctlr->pump_messages, spi_pump_messages);
1663
1664         /*
1665          * Controller config will indicate if this controller should run the
1666          * message pump with high (realtime) priority to reduce the transfer
1667          * latency on the bus by minimising the delay between a transfer
1668          * request and the scheduling of the message pump thread. Without this
1669          * setting the message pump thread will remain at default priority.
1670          */
1671         if (ctlr->rt)
1672                 spi_set_thread_rt(ctlr);
1673
1674         return 0;
1675 }
1676
1677 /**
1678  * spi_get_next_queued_message() - called by driver to check for queued
1679  * messages
1680  * @ctlr: the controller to check for queued messages
1681  *
1682  * If there are more messages in the queue, the next message is returned from
1683  * this call.
1684  *
1685  * Return: the next message in the queue, else NULL if the queue is empty.
1686  */
1687 struct spi_message *spi_get_next_queued_message(struct spi_controller *ctlr)
1688 {
1689         struct spi_message *next;
1690         unsigned long flags;
1691
1692         /* get a pointer to the next message, if any */
1693         spin_lock_irqsave(&ctlr->queue_lock, flags);
1694         next = list_first_entry_or_null(&ctlr->queue, struct spi_message,
1695                                         queue);
1696         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1697
1698         return next;
1699 }
1700 EXPORT_SYMBOL_GPL(spi_get_next_queued_message);
1701
1702 /**
1703  * spi_finalize_current_message() - the current message is complete
1704  * @ctlr: the controller to return the message to
1705  *
1706  * Called by the driver to notify the core that the message in the front of the
1707  * queue is complete and can be removed from the queue.
1708  */
1709 void spi_finalize_current_message(struct spi_controller *ctlr)
1710 {
1711         struct spi_transfer *xfer;
1712         struct spi_message *mesg;
1713         unsigned long flags;
1714         int ret;
1715
1716         spin_lock_irqsave(&ctlr->queue_lock, flags);
1717         mesg = ctlr->cur_msg;
1718         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1719
1720         if (!ctlr->ptp_sts_supported && !ctlr->transfer_one) {
1721                 list_for_each_entry(xfer, &mesg->transfers, transfer_list) {
1722                         ptp_read_system_postts(xfer->ptp_sts);
1723                         xfer->ptp_sts_word_post = xfer->len;
1724                 }
1725         }
1726
1727         if (unlikely(ctlr->ptp_sts_supported))
1728                 list_for_each_entry(xfer, &mesg->transfers, transfer_list)
1729                         WARN_ON_ONCE(xfer->ptp_sts && !xfer->timestamped);
1730
1731         spi_unmap_msg(ctlr, mesg);
1732
1733         /* In the prepare_messages callback the spi bus has the opportunity to
1734          * split a transfer to smaller chunks.
1735          * Release splited transfers here since spi_map_msg is done on the
1736          * splited transfers.
1737          */
1738         spi_res_release(ctlr, mesg);
1739
1740         if (ctlr->cur_msg_prepared && ctlr->unprepare_message) {
1741                 ret = ctlr->unprepare_message(ctlr, mesg);
1742                 if (ret) {
1743                         dev_err(&ctlr->dev, "failed to unprepare message: %d\n",
1744                                 ret);
1745                 }
1746         }
1747
1748         spin_lock_irqsave(&ctlr->queue_lock, flags);
1749         ctlr->cur_msg = NULL;
1750         ctlr->cur_msg_prepared = false;
1751         ctlr->fallback = false;
1752         kthread_queue_work(ctlr->kworker, &ctlr->pump_messages);
1753         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1754
1755         trace_spi_message_done(mesg);
1756
1757         mesg->state = NULL;
1758         if (mesg->complete)
1759                 mesg->complete(mesg->context);
1760 }
1761 EXPORT_SYMBOL_GPL(spi_finalize_current_message);
1762
1763 static int spi_start_queue(struct spi_controller *ctlr)
1764 {
1765         unsigned long flags;
1766
1767         spin_lock_irqsave(&ctlr->queue_lock, flags);
1768
1769         if (ctlr->running || ctlr->busy) {
1770                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1771                 return -EBUSY;
1772         }
1773
1774         ctlr->running = true;
1775         ctlr->cur_msg = NULL;
1776         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1777
1778         kthread_queue_work(ctlr->kworker, &ctlr->pump_messages);
1779
1780         return 0;
1781 }
1782
1783 static int spi_stop_queue(struct spi_controller *ctlr)
1784 {
1785         unsigned long flags;
1786         unsigned limit = 500;
1787         int ret = 0;
1788
1789         spin_lock_irqsave(&ctlr->queue_lock, flags);
1790
1791         /*
1792          * This is a bit lame, but is optimized for the common execution path.
1793          * A wait_queue on the ctlr->busy could be used, but then the common
1794          * execution path (pump_messages) would be required to call wake_up or
1795          * friends on every SPI message. Do this instead.
1796          */
1797         while ((!list_empty(&ctlr->queue) || ctlr->busy) && limit--) {
1798                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1799                 usleep_range(10000, 11000);
1800                 spin_lock_irqsave(&ctlr->queue_lock, flags);
1801         }
1802
1803         if (!list_empty(&ctlr->queue) || ctlr->busy)
1804                 ret = -EBUSY;
1805         else
1806                 ctlr->running = false;
1807
1808         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1809
1810         if (ret) {
1811                 dev_warn(&ctlr->dev, "could not stop message queue\n");
1812                 return ret;
1813         }
1814         return ret;
1815 }
1816
1817 static int spi_destroy_queue(struct spi_controller *ctlr)
1818 {
1819         int ret;
1820
1821         ret = spi_stop_queue(ctlr);
1822
1823         /*
1824          * kthread_flush_worker will block until all work is done.
1825          * If the reason that stop_queue timed out is that the work will never
1826          * finish, then it does no good to call flush/stop thread, so
1827          * return anyway.
1828          */
1829         if (ret) {
1830                 dev_err(&ctlr->dev, "problem destroying queue\n");
1831                 return ret;
1832         }
1833
1834         kthread_destroy_worker(ctlr->kworker);
1835
1836         return 0;
1837 }
1838
1839 static int __spi_queued_transfer(struct spi_device *spi,
1840                                  struct spi_message *msg,
1841                                  bool need_pump)
1842 {
1843         struct spi_controller *ctlr = spi->controller;
1844         unsigned long flags;
1845
1846         spin_lock_irqsave(&ctlr->queue_lock, flags);
1847
1848         if (!ctlr->running) {
1849                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1850                 return -ESHUTDOWN;
1851         }
1852         msg->actual_length = 0;
1853         msg->status = -EINPROGRESS;
1854
1855         list_add_tail(&msg->queue, &ctlr->queue);
1856         if (!ctlr->busy && need_pump)
1857                 kthread_queue_work(ctlr->kworker, &ctlr->pump_messages);
1858
1859         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1860         return 0;
1861 }
1862
1863 /**
1864  * spi_queued_transfer - transfer function for queued transfers
1865  * @spi: spi device which is requesting transfer
1866  * @msg: spi message which is to handled is queued to driver queue
1867  *
1868  * Return: zero on success, else a negative error code.
1869  */
1870 static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
1871 {
1872         return __spi_queued_transfer(spi, msg, true);
1873 }
1874
1875 static int spi_controller_initialize_queue(struct spi_controller *ctlr)
1876 {
1877         int ret;
1878
1879         ctlr->transfer = spi_queued_transfer;
1880         if (!ctlr->transfer_one_message)
1881                 ctlr->transfer_one_message = spi_transfer_one_message;
1882
1883         /* Initialize and start queue */
1884         ret = spi_init_queue(ctlr);
1885         if (ret) {
1886                 dev_err(&ctlr->dev, "problem initializing queue\n");
1887                 goto err_init_queue;
1888         }
1889         ctlr->queued = true;
1890         ret = spi_start_queue(ctlr);
1891         if (ret) {
1892                 dev_err(&ctlr->dev, "problem starting queue\n");
1893                 goto err_start_queue;
1894         }
1895
1896         return 0;
1897
1898 err_start_queue:
1899         spi_destroy_queue(ctlr);
1900 err_init_queue:
1901         return ret;
1902 }
1903
1904 /**
1905  * spi_flush_queue - Send all pending messages in the queue from the callers'
1906  *                   context
1907  * @ctlr: controller to process queue for
1908  *
1909  * This should be used when one wants to ensure all pending messages have been
1910  * sent before doing something. Is used by the spi-mem code to make sure SPI
1911  * memory operations do not preempt regular SPI transfers that have been queued
1912  * before the spi-mem operation.
1913  */
1914 void spi_flush_queue(struct spi_controller *ctlr)
1915 {
1916         if (ctlr->transfer == spi_queued_transfer)
1917                 __spi_pump_messages(ctlr, false);
1918 }
1919
1920 /*-------------------------------------------------------------------------*/
1921
1922 #if defined(CONFIG_OF)
1923 static int of_spi_parse_dt(struct spi_controller *ctlr, struct spi_device *spi,
1924                            struct device_node *nc)
1925 {
1926         u32 value;
1927         int rc;
1928
1929         /* Mode (clock phase/polarity/etc.) */
1930         if (of_property_read_bool(nc, "spi-cpha"))
1931                 spi->mode |= SPI_CPHA;
1932         if (of_property_read_bool(nc, "spi-cpol"))
1933                 spi->mode |= SPI_CPOL;
1934         if (of_property_read_bool(nc, "spi-3wire"))
1935                 spi->mode |= SPI_3WIRE;
1936         if (of_property_read_bool(nc, "spi-lsb-first"))
1937                 spi->mode |= SPI_LSB_FIRST;
1938         if (of_property_read_bool(nc, "spi-cs-high"))
1939                 spi->mode |= SPI_CS_HIGH;
1940
1941         /* Device DUAL/QUAD mode */
1942         if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) {
1943                 switch (value) {
1944                 case 1:
1945                         break;
1946                 case 2:
1947                         spi->mode |= SPI_TX_DUAL;
1948                         break;
1949                 case 4:
1950                         spi->mode |= SPI_TX_QUAD;
1951                         break;
1952                 case 8:
1953                         spi->mode |= SPI_TX_OCTAL;
1954                         break;
1955                 default:
1956                         dev_warn(&ctlr->dev,
1957                                 "spi-tx-bus-width %d not supported\n",
1958                                 value);
1959                         break;
1960                 }
1961         }
1962
1963         if (!of_property_read_u32(nc, "spi-rx-bus-width", &value)) {
1964                 switch (value) {
1965                 case 1:
1966                         break;
1967                 case 2:
1968                         spi->mode |= SPI_RX_DUAL;
1969                         break;
1970                 case 4:
1971                         spi->mode |= SPI_RX_QUAD;
1972                         break;
1973                 case 8:
1974                         spi->mode |= SPI_RX_OCTAL;
1975                         break;
1976                 default:
1977                         dev_warn(&ctlr->dev,
1978                                 "spi-rx-bus-width %d not supported\n",
1979                                 value);
1980                         break;
1981                 }
1982         }
1983
1984         if (spi_controller_is_slave(ctlr)) {
1985                 if (!of_node_name_eq(nc, "slave")) {
1986                         dev_err(&ctlr->dev, "%pOF is not called 'slave'\n",
1987                                 nc);
1988                         return -EINVAL;
1989                 }
1990                 return 0;
1991         }
1992
1993         /* Device address */
1994         rc = of_property_read_u32(nc, "reg", &value);
1995         if (rc) {
1996                 dev_err(&ctlr->dev, "%pOF has no valid 'reg' property (%d)\n",
1997                         nc, rc);
1998                 return rc;
1999         }
2000         spi->chip_select = value;
2001
2002         /* Device speed */
2003         if (!of_property_read_u32(nc, "spi-max-frequency", &value))
2004                 spi->max_speed_hz = value;
2005
2006         return 0;
2007 }
2008
2009 static struct spi_device *
2010 of_register_spi_device(struct spi_controller *ctlr, struct device_node *nc)
2011 {
2012         struct spi_device *spi;
2013         int rc;
2014
2015         /* Alloc an spi_device */
2016         spi = spi_alloc_device(ctlr);
2017         if (!spi) {
2018                 dev_err(&ctlr->dev, "spi_device alloc error for %pOF\n", nc);
2019                 rc = -ENOMEM;
2020                 goto err_out;
2021         }
2022
2023         /* Select device driver */
2024         rc = of_modalias_node(nc, spi->modalias,
2025                                 sizeof(spi->modalias));
2026         if (rc < 0) {
2027                 dev_err(&ctlr->dev, "cannot find modalias for %pOF\n", nc);
2028                 goto err_out;
2029         }
2030
2031         rc = of_spi_parse_dt(ctlr, spi, nc);
2032         if (rc)
2033                 goto err_out;
2034
2035         /* Store a pointer to the node in the device structure */
2036         of_node_get(nc);
2037         spi->dev.of_node = nc;
2038
2039         /* Register the new device */
2040         rc = spi_add_device(spi);
2041         if (rc) {
2042                 dev_err(&ctlr->dev, "spi_device register error %pOF\n", nc);
2043                 goto err_of_node_put;
2044         }
2045
2046         return spi;
2047
2048 err_of_node_put:
2049         of_node_put(nc);
2050 err_out:
2051         spi_dev_put(spi);
2052         return ERR_PTR(rc);
2053 }
2054
2055 /**
2056  * of_register_spi_devices() - Register child devices onto the SPI bus
2057  * @ctlr:       Pointer to spi_controller device
2058  *
2059  * Registers an spi_device for each child node of controller node which
2060  * represents a valid SPI slave.
2061  */
2062 static void of_register_spi_devices(struct spi_controller *ctlr)
2063 {
2064         struct spi_device *spi;
2065         struct device_node *nc;
2066
2067         if (!ctlr->dev.of_node)
2068                 return;
2069
2070         for_each_available_child_of_node(ctlr->dev.of_node, nc) {
2071                 if (of_node_test_and_set_flag(nc, OF_POPULATED))
2072                         continue;
2073                 spi = of_register_spi_device(ctlr, nc);
2074                 if (IS_ERR(spi)) {
2075                         dev_warn(&ctlr->dev,
2076                                  "Failed to create SPI device for %pOF\n", nc);
2077                         of_node_clear_flag(nc, OF_POPULATED);
2078                 }
2079         }
2080 }
2081 #else
2082 static void of_register_spi_devices(struct spi_controller *ctlr) { }
2083 #endif
2084
2085 #ifdef CONFIG_ACPI
2086 struct acpi_spi_lookup {
2087         struct spi_controller   *ctlr;
2088         u32                     max_speed_hz;
2089         u32                     mode;
2090         int                     irq;
2091         u8                      bits_per_word;
2092         u8                      chip_select;
2093 };
2094
2095 static void acpi_spi_parse_apple_properties(struct acpi_device *dev,
2096                                             struct acpi_spi_lookup *lookup)
2097 {
2098         const union acpi_object *obj;
2099
2100         if (!x86_apple_machine)
2101                 return;
2102
2103         if (!acpi_dev_get_property(dev, "spiSclkPeriod", ACPI_TYPE_BUFFER, &obj)
2104             && obj->buffer.length >= 4)
2105                 lookup->max_speed_hz  = NSEC_PER_SEC / *(u32 *)obj->buffer.pointer;
2106
2107         if (!acpi_dev_get_property(dev, "spiWordSize", ACPI_TYPE_BUFFER, &obj)
2108             && obj->buffer.length == 8)
2109                 lookup->bits_per_word = *(u64 *)obj->buffer.pointer;
2110
2111         if (!acpi_dev_get_property(dev, "spiBitOrder", ACPI_TYPE_BUFFER, &obj)
2112             && obj->buffer.length == 8 && !*(u64 *)obj->buffer.pointer)
2113                 lookup->mode |= SPI_LSB_FIRST;
2114
2115         if (!acpi_dev_get_property(dev, "spiSPO", ACPI_TYPE_BUFFER, &obj)
2116             && obj->buffer.length == 8 &&  *(u64 *)obj->buffer.pointer)
2117                 lookup->mode |= SPI_CPOL;
2118
2119         if (!acpi_dev_get_property(dev, "spiSPH", ACPI_TYPE_BUFFER, &obj)
2120             && obj->buffer.length == 8 &&  *(u64 *)obj->buffer.pointer)
2121                 lookup->mode |= SPI_CPHA;
2122 }
2123
2124 static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
2125 {
2126         struct acpi_spi_lookup *lookup = data;
2127         struct spi_controller *ctlr = lookup->ctlr;
2128
2129         if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
2130                 struct acpi_resource_spi_serialbus *sb;
2131                 acpi_handle parent_handle;
2132                 acpi_status status;
2133
2134                 sb = &ares->data.spi_serial_bus;
2135                 if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) {
2136
2137                         status = acpi_get_handle(NULL,
2138                                                  sb->resource_source.string_ptr,
2139                                                  &parent_handle);
2140
2141                         if (ACPI_FAILURE(status) ||
2142                             ACPI_HANDLE(ctlr->dev.parent) != parent_handle)
2143                                 return -ENODEV;
2144
2145                         /*
2146                          * ACPI DeviceSelection numbering is handled by the
2147                          * host controller driver in Windows and can vary
2148                          * from driver to driver. In Linux we always expect
2149                          * 0 .. max - 1 so we need to ask the driver to
2150                          * translate between the two schemes.
2151                          */
2152                         if (ctlr->fw_translate_cs) {
2153                                 int cs = ctlr->fw_translate_cs(ctlr,
2154                                                 sb->device_selection);
2155                                 if (cs < 0)
2156                                         return cs;
2157                                 lookup->chip_select = cs;
2158                         } else {
2159                                 lookup->chip_select = sb->device_selection;
2160                         }
2161
2162                         lookup->max_speed_hz = sb->connection_speed;
2163                         lookup->bits_per_word = sb->data_bit_length;
2164
2165                         if (sb->clock_phase == ACPI_SPI_SECOND_PHASE)
2166                                 lookup->mode |= SPI_CPHA;
2167                         if (sb->clock_polarity == ACPI_SPI_START_HIGH)
2168                                 lookup->mode |= SPI_CPOL;
2169                         if (sb->device_polarity == ACPI_SPI_ACTIVE_HIGH)
2170                                 lookup->mode |= SPI_CS_HIGH;
2171                 }
2172         } else if (lookup->irq < 0) {
2173                 struct resource r;
2174
2175                 if (acpi_dev_resource_interrupt(ares, 0, &r))
2176                         lookup->irq = r.start;
2177         }
2178
2179         /* Always tell the ACPI core to skip this resource */
2180         return 1;
2181 }
2182
2183 static acpi_status acpi_register_spi_device(struct spi_controller *ctlr,
2184                                             struct acpi_device *adev)
2185 {
2186         acpi_handle parent_handle = NULL;
2187         struct list_head resource_list;
2188         struct acpi_spi_lookup lookup = {};
2189         struct spi_device *spi;
2190         int ret;
2191
2192         if (acpi_bus_get_status(adev) || !adev->status.present ||
2193             acpi_device_enumerated(adev))
2194                 return AE_OK;
2195
2196         lookup.ctlr             = ctlr;
2197         lookup.irq              = -1;
2198
2199         INIT_LIST_HEAD(&resource_list);
2200         ret = acpi_dev_get_resources(adev, &resource_list,
2201                                      acpi_spi_add_resource, &lookup);
2202         acpi_dev_free_resource_list(&resource_list);
2203
2204         if (ret < 0)
2205                 /* found SPI in _CRS but it points to another controller */
2206                 return AE_OK;
2207
2208         if (!lookup.max_speed_hz &&
2209             !ACPI_FAILURE(acpi_get_parent(adev->handle, &parent_handle)) &&
2210             ACPI_HANDLE(ctlr->dev.parent) == parent_handle) {
2211                 /* Apple does not use _CRS but nested devices for SPI slaves */
2212                 acpi_spi_parse_apple_properties(adev, &lookup);
2213         }
2214
2215         if (!lookup.max_speed_hz)
2216                 return AE_OK;
2217
2218         spi = spi_alloc_device(ctlr);
2219         if (!spi) {
2220                 dev_err(&ctlr->dev, "failed to allocate SPI device for %s\n",
2221                         dev_name(&adev->dev));
2222                 return AE_NO_MEMORY;
2223         }
2224
2225
2226         ACPI_COMPANION_SET(&spi->dev, adev);
2227         spi->max_speed_hz       = lookup.max_speed_hz;
2228         spi->mode               |= lookup.mode;
2229         spi->irq                = lookup.irq;
2230         spi->bits_per_word      = lookup.bits_per_word;
2231         spi->chip_select        = lookup.chip_select;
2232
2233         acpi_set_modalias(adev, acpi_device_hid(adev), spi->modalias,
2234                           sizeof(spi->modalias));
2235
2236         if (spi->irq < 0)
2237                 spi->irq = acpi_dev_gpio_irq_get(adev, 0);
2238
2239         acpi_device_set_enumerated(adev);
2240
2241         adev->power.flags.ignore_parent = true;
2242         if (spi_add_device(spi)) {
2243                 adev->power.flags.ignore_parent = false;
2244                 dev_err(&ctlr->dev, "failed to add SPI device %s from ACPI\n",
2245                         dev_name(&adev->dev));
2246                 spi_dev_put(spi);
2247         }
2248
2249         return AE_OK;
2250 }
2251
2252 static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level,
2253                                        void *data, void **return_value)
2254 {
2255         struct spi_controller *ctlr = data;
2256         struct acpi_device *adev;
2257
2258         if (acpi_bus_get_device(handle, &adev))
2259                 return AE_OK;
2260
2261         return acpi_register_spi_device(ctlr, adev);
2262 }
2263
2264 #define SPI_ACPI_ENUMERATE_MAX_DEPTH            32
2265
2266 static void acpi_register_spi_devices(struct spi_controller *ctlr)
2267 {
2268         acpi_status status;
2269         acpi_handle handle;
2270
2271         handle = ACPI_HANDLE(ctlr->dev.parent);
2272         if (!handle)
2273                 return;
2274
2275         status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
2276                                      SPI_ACPI_ENUMERATE_MAX_DEPTH,
2277                                      acpi_spi_add_device, NULL, ctlr, NULL);
2278         if (ACPI_FAILURE(status))
2279                 dev_warn(&ctlr->dev, "failed to enumerate SPI slaves\n");
2280 }
2281 #else
2282 static inline void acpi_register_spi_devices(struct spi_controller *ctlr) {}
2283 #endif /* CONFIG_ACPI */
2284
2285 static void spi_controller_release(struct device *dev)
2286 {
2287         struct spi_controller *ctlr;
2288
2289         ctlr = container_of(dev, struct spi_controller, dev);
2290         kfree(ctlr);
2291 }
2292
2293 static struct class spi_master_class = {
2294         .name           = "spi_master",
2295         .owner          = THIS_MODULE,
2296         .dev_release    = spi_controller_release,
2297         .dev_groups     = spi_master_groups,
2298 };
2299
2300 #ifdef CONFIG_SPI_SLAVE
2301 /**
2302  * spi_slave_abort - abort the ongoing transfer request on an SPI slave
2303  *                   controller
2304  * @spi: device used for the current transfer
2305  */
2306 int spi_slave_abort(struct spi_device *spi)
2307 {
2308         struct spi_controller *ctlr = spi->controller;
2309
2310         if (spi_controller_is_slave(ctlr) && ctlr->slave_abort)
2311                 return ctlr->slave_abort(ctlr);
2312
2313         return -ENOTSUPP;
2314 }
2315 EXPORT_SYMBOL_GPL(spi_slave_abort);
2316
2317 static int match_true(struct device *dev, void *data)
2318 {
2319         return 1;
2320 }
2321
2322 static ssize_t slave_show(struct device *dev, struct device_attribute *attr,
2323                           char *buf)
2324 {
2325         struct spi_controller *ctlr = container_of(dev, struct spi_controller,
2326                                                    dev);
2327         struct device *child;
2328
2329         child = device_find_child(&ctlr->dev, NULL, match_true);
2330         return sprintf(buf, "%s\n",
2331                        child ? to_spi_device(child)->modalias : NULL);
2332 }
2333
2334 static ssize_t slave_store(struct device *dev, struct device_attribute *attr,
2335                            const char *buf, size_t count)
2336 {
2337         struct spi_controller *ctlr = container_of(dev, struct spi_controller,
2338                                                    dev);
2339         struct spi_device *spi;
2340         struct device *child;
2341         char name[32];
2342         int rc;
2343
2344         rc = sscanf(buf, "%31s", name);
2345         if (rc != 1 || !name[0])
2346                 return -EINVAL;
2347
2348         child = device_find_child(&ctlr->dev, NULL, match_true);
2349         if (child) {
2350                 /* Remove registered slave */
2351                 device_unregister(child);
2352                 put_device(child);
2353         }
2354
2355         if (strcmp(name, "(null)")) {
2356                 /* Register new slave */
2357                 spi = spi_alloc_device(ctlr);
2358                 if (!spi)
2359                         return -ENOMEM;
2360
2361                 strlcpy(spi->modalias, name, sizeof(spi->modalias));
2362
2363                 rc = spi_add_device(spi);
2364                 if (rc) {
2365                         spi_dev_put(spi);
2366                         return rc;
2367                 }
2368         }
2369
2370         return count;
2371 }
2372
2373 static DEVICE_ATTR_RW(slave);
2374
2375 static struct attribute *spi_slave_attrs[] = {
2376         &dev_attr_slave.attr,
2377         NULL,
2378 };
2379
2380 static const struct attribute_group spi_slave_group = {
2381         .attrs = spi_slave_attrs,
2382 };
2383
2384 static const struct attribute_group *spi_slave_groups[] = {
2385         &spi_controller_statistics_group,
2386         &spi_slave_group,
2387         NULL,
2388 };
2389
2390 static struct class spi_slave_class = {
2391         .name           = "spi_slave",
2392         .owner          = THIS_MODULE,
2393         .dev_release    = spi_controller_release,
2394         .dev_groups     = spi_slave_groups,
2395 };
2396 #else
2397 extern struct class spi_slave_class;    /* dummy */
2398 #endif
2399
2400 /**
2401  * __spi_alloc_controller - allocate an SPI master or slave controller
2402  * @dev: the controller, possibly using the platform_bus
2403  * @size: how much zeroed driver-private data to allocate; the pointer to this
2404  *      memory is in the driver_data field of the returned device, accessible
2405  *      with spi_controller_get_devdata(); the memory is cacheline aligned;
2406  *      drivers granting DMA access to portions of their private data need to
2407  *      round up @size using ALIGN(size, dma_get_cache_alignment()).
2408  * @slave: flag indicating whether to allocate an SPI master (false) or SPI
2409  *      slave (true) controller
2410  * Context: can sleep
2411  *
2412  * This call is used only by SPI controller drivers, which are the
2413  * only ones directly touching chip registers.  It's how they allocate
2414  * an spi_controller structure, prior to calling spi_register_controller().
2415  *
2416  * This must be called from context that can sleep.
2417  *
2418  * The caller is responsible for assigning the bus number and initializing the
2419  * controller's methods before calling spi_register_controller(); and (after
2420  * errors adding the device) calling spi_controller_put() to prevent a memory
2421  * leak.
2422  *
2423  * Return: the SPI controller structure on success, else NULL.
2424  */
2425 struct spi_controller *__spi_alloc_controller(struct device *dev,
2426                                               unsigned int size, bool slave)
2427 {
2428         struct spi_controller   *ctlr;
2429         size_t ctlr_size = ALIGN(sizeof(*ctlr), dma_get_cache_alignment());
2430
2431         if (!dev)
2432                 return NULL;
2433
2434         ctlr = kzalloc(size + ctlr_size, GFP_KERNEL);
2435         if (!ctlr)
2436                 return NULL;
2437
2438         device_initialize(&ctlr->dev);
2439         ctlr->bus_num = -1;
2440         ctlr->num_chipselect = 1;
2441         ctlr->slave = slave;
2442         if (IS_ENABLED(CONFIG_SPI_SLAVE) && slave)
2443                 ctlr->dev.class = &spi_slave_class;
2444         else
2445                 ctlr->dev.class = &spi_master_class;
2446         ctlr->dev.parent = dev;
2447         pm_suspend_ignore_children(&ctlr->dev, true);
2448         spi_controller_set_devdata(ctlr, (void *)ctlr + ctlr_size);
2449
2450         return ctlr;
2451 }
2452 EXPORT_SYMBOL_GPL(__spi_alloc_controller);
2453
2454 static void devm_spi_release_controller(struct device *dev, void *ctlr)
2455 {
2456         spi_controller_put(*(struct spi_controller **)ctlr);
2457 }
2458
2459 /**
2460  * __devm_spi_alloc_controller - resource-managed __spi_alloc_controller()
2461  * @dev: physical device of SPI controller
2462  * @size: how much zeroed driver-private data to allocate
2463  * @slave: whether to allocate an SPI master (false) or SPI slave (true)
2464  * Context: can sleep
2465  *
2466  * Allocate an SPI controller and automatically release a reference on it
2467  * when @dev is unbound from its driver.  Drivers are thus relieved from
2468  * having to call spi_controller_put().
2469  *
2470  * The arguments to this function are identical to __spi_alloc_controller().
2471  *
2472  * Return: the SPI controller structure on success, else NULL.
2473  */
2474 struct spi_controller *__devm_spi_alloc_controller(struct device *dev,
2475                                                    unsigned int size,
2476                                                    bool slave)
2477 {
2478         struct spi_controller **ptr, *ctlr;
2479
2480         ptr = devres_alloc(devm_spi_release_controller, sizeof(*ptr),
2481                            GFP_KERNEL);
2482         if (!ptr)
2483                 return NULL;
2484
2485         ctlr = __spi_alloc_controller(dev, size, slave);
2486         if (ctlr) {
2487                 *ptr = ctlr;
2488                 devres_add(dev, ptr);
2489         } else {
2490                 devres_free(ptr);
2491         }
2492
2493         return ctlr;
2494 }
2495 EXPORT_SYMBOL_GPL(__devm_spi_alloc_controller);
2496
2497 #ifdef CONFIG_OF
2498 static int of_spi_get_gpio_numbers(struct spi_controller *ctlr)
2499 {
2500         int nb, i, *cs;
2501         struct device_node *np = ctlr->dev.of_node;
2502
2503         if (!np)
2504                 return 0;
2505
2506         nb = of_gpio_named_count(np, "cs-gpios");
2507         ctlr->num_chipselect = max_t(int, nb, ctlr->num_chipselect);
2508
2509         /* Return error only for an incorrectly formed cs-gpios property */
2510         if (nb == 0 || nb == -ENOENT)
2511                 return 0;
2512         else if (nb < 0)
2513                 return nb;
2514
2515         cs = devm_kcalloc(&ctlr->dev, ctlr->num_chipselect, sizeof(int),
2516                           GFP_KERNEL);
2517         ctlr->cs_gpios = cs;
2518
2519         if (!ctlr->cs_gpios)
2520                 return -ENOMEM;
2521
2522         for (i = 0; i < ctlr->num_chipselect; i++)
2523                 cs[i] = -ENOENT;
2524
2525         for (i = 0; i < nb; i++)
2526                 cs[i] = of_get_named_gpio(np, "cs-gpios", i);
2527
2528         return 0;
2529 }
2530 #else
2531 static int of_spi_get_gpio_numbers(struct spi_controller *ctlr)
2532 {
2533         return 0;
2534 }
2535 #endif
2536
2537 /**
2538  * spi_get_gpio_descs() - grab chip select GPIOs for the master
2539  * @ctlr: The SPI master to grab GPIO descriptors for
2540  */
2541 static int spi_get_gpio_descs(struct spi_controller *ctlr)
2542 {
2543         int nb, i;
2544         struct gpio_desc **cs;
2545         struct device *dev = &ctlr->dev;
2546         unsigned long native_cs_mask = 0;
2547         unsigned int num_cs_gpios = 0;
2548
2549         nb = gpiod_count(dev, "cs");
2550         ctlr->num_chipselect = max_t(int, nb, ctlr->num_chipselect);
2551
2552         /* No GPIOs at all is fine, else return the error */
2553         if (nb == 0 || nb == -ENOENT)
2554                 return 0;
2555         else if (nb < 0)
2556                 return nb;
2557
2558         cs = devm_kcalloc(dev, ctlr->num_chipselect, sizeof(*cs),
2559                           GFP_KERNEL);
2560         if (!cs)
2561                 return -ENOMEM;
2562         ctlr->cs_gpiods = cs;
2563
2564         for (i = 0; i < nb; i++) {
2565                 /*
2566                  * Most chipselects are active low, the inverted
2567                  * semantics are handled by special quirks in gpiolib,
2568                  * so initializing them GPIOD_OUT_LOW here means
2569                  * "unasserted", in most cases this will drive the physical
2570                  * line high.
2571                  */
2572                 cs[i] = devm_gpiod_get_index_optional(dev, "cs", i,
2573                                                       GPIOD_OUT_LOW);
2574                 if (IS_ERR(cs[i]))
2575                         return PTR_ERR(cs[i]);
2576
2577                 if (cs[i]) {
2578                         /*
2579                          * If we find a CS GPIO, name it after the device and
2580                          * chip select line.
2581                          */
2582                         char *gpioname;
2583
2584                         gpioname = devm_kasprintf(dev, GFP_KERNEL, "%s CS%d",
2585                                                   dev_name(dev), i);
2586                         if (!gpioname)
2587                                 return -ENOMEM;
2588                         gpiod_set_consumer_name(cs[i], gpioname);
2589                         num_cs_gpios++;
2590                         continue;
2591                 }
2592
2593                 if (ctlr->max_native_cs && i >= ctlr->max_native_cs) {
2594                         dev_err(dev, "Invalid native chip select %d\n", i);
2595                         return -EINVAL;
2596                 }
2597                 native_cs_mask |= BIT(i);
2598         }
2599
2600         ctlr->unused_native_cs = ffz(native_cs_mask);
2601         if (num_cs_gpios && ctlr->max_native_cs &&
2602             ctlr->unused_native_cs >= ctlr->max_native_cs) {
2603                 dev_err(dev, "No unused native chip select available\n");
2604                 return -EINVAL;
2605         }
2606
2607         return 0;
2608 }
2609
2610 static int spi_controller_check_ops(struct spi_controller *ctlr)
2611 {
2612         /*
2613          * The controller may implement only the high-level SPI-memory like
2614          * operations if it does not support regular SPI transfers, and this is
2615          * valid use case.
2616          * If ->mem_ops is NULL, we request that at least one of the
2617          * ->transfer_xxx() method be implemented.
2618          */
2619         if (ctlr->mem_ops) {
2620                 if (!ctlr->mem_ops->exec_op)
2621                         return -EINVAL;
2622         } else if (!ctlr->transfer && !ctlr->transfer_one &&
2623                    !ctlr->transfer_one_message) {
2624                 return -EINVAL;
2625         }
2626
2627         return 0;
2628 }
2629
2630 /**
2631  * spi_register_controller - register SPI master or slave controller
2632  * @ctlr: initialized master, originally from spi_alloc_master() or
2633  *      spi_alloc_slave()
2634  * Context: can sleep
2635  *
2636  * SPI controllers connect to their drivers using some non-SPI bus,
2637  * such as the platform bus.  The final stage of probe() in that code
2638  * includes calling spi_register_controller() to hook up to this SPI bus glue.
2639  *
2640  * SPI controllers use board specific (often SOC specific) bus numbers,
2641  * and board-specific addressing for SPI devices combines those numbers
2642  * with chip select numbers.  Since SPI does not directly support dynamic
2643  * device identification, boards need configuration tables telling which
2644  * chip is at which address.
2645  *
2646  * This must be called from context that can sleep.  It returns zero on
2647  * success, else a negative error code (dropping the controller's refcount).
2648  * After a successful return, the caller is responsible for calling
2649  * spi_unregister_controller().
2650  *
2651  * Return: zero on success, else a negative error code.
2652  */
2653 int spi_register_controller(struct spi_controller *ctlr)
2654 {
2655         struct device           *dev = ctlr->dev.parent;
2656         struct boardinfo        *bi;
2657         int                     status;
2658         int                     id, first_dynamic;
2659
2660         if (!dev)
2661                 return -ENODEV;
2662
2663         /*
2664          * Make sure all necessary hooks are implemented before registering
2665          * the SPI controller.
2666          */
2667         status = spi_controller_check_ops(ctlr);
2668         if (status)
2669                 return status;
2670
2671         if (ctlr->bus_num >= 0) {
2672                 /* devices with a fixed bus num must check-in with the num */
2673                 mutex_lock(&board_lock);
2674                 id = idr_alloc(&spi_master_idr, ctlr, ctlr->bus_num,
2675                         ctlr->bus_num + 1, GFP_KERNEL);
2676                 mutex_unlock(&board_lock);
2677                 if (WARN(id < 0, "couldn't get idr"))
2678                         return id == -ENOSPC ? -EBUSY : id;
2679                 ctlr->bus_num = id;
2680         } else if (ctlr->dev.of_node) {
2681                 /* allocate dynamic bus number using Linux idr */
2682                 id = of_alias_get_id(ctlr->dev.of_node, "spi");
2683                 if (id >= 0) {
2684                         ctlr->bus_num = id;
2685                         mutex_lock(&board_lock);
2686                         id = idr_alloc(&spi_master_idr, ctlr, ctlr->bus_num,
2687                                        ctlr->bus_num + 1, GFP_KERNEL);
2688                         mutex_unlock(&board_lock);
2689                         if (WARN(id < 0, "couldn't get idr"))
2690                                 return id == -ENOSPC ? -EBUSY : id;
2691                 }
2692         }
2693         if (ctlr->bus_num < 0) {
2694                 first_dynamic = of_alias_get_highest_id("spi");
2695                 if (first_dynamic < 0)
2696                         first_dynamic = 0;
2697                 else
2698                         first_dynamic++;
2699
2700                 mutex_lock(&board_lock);
2701                 id = idr_alloc(&spi_master_idr, ctlr, first_dynamic,
2702                                0, GFP_KERNEL);
2703                 mutex_unlock(&board_lock);
2704                 if (WARN(id < 0, "couldn't get idr"))
2705                         return id;
2706                 ctlr->bus_num = id;
2707         }
2708         INIT_LIST_HEAD(&ctlr->queue);
2709         spin_lock_init(&ctlr->queue_lock);
2710         spin_lock_init(&ctlr->bus_lock_spinlock);
2711         mutex_init(&ctlr->bus_lock_mutex);
2712         mutex_init(&ctlr->io_mutex);
2713         ctlr->bus_lock_flag = 0;
2714         init_completion(&ctlr->xfer_completion);
2715         if (!ctlr->max_dma_len)
2716                 ctlr->max_dma_len = INT_MAX;
2717
2718         /* register the device, then userspace will see it.
2719          * registration fails if the bus ID is in use.
2720          */
2721         dev_set_name(&ctlr->dev, "spi%u", ctlr->bus_num);
2722
2723         if (!spi_controller_is_slave(ctlr)) {
2724                 if (ctlr->use_gpio_descriptors) {
2725                         status = spi_get_gpio_descs(ctlr);
2726                         if (status)
2727                                 goto free_bus_id;
2728                         /*
2729                          * A controller using GPIO descriptors always
2730                          * supports SPI_CS_HIGH if need be.
2731                          */
2732                         ctlr->mode_bits |= SPI_CS_HIGH;
2733                 } else {
2734                         /* Legacy code path for GPIOs from DT */
2735                         status = of_spi_get_gpio_numbers(ctlr);
2736                         if (status)
2737                                 goto free_bus_id;
2738                 }
2739         }
2740
2741         /*
2742          * Even if it's just one always-selected device, there must
2743          * be at least one chipselect.
2744          */
2745         if (!ctlr->num_chipselect) {
2746                 status = -EINVAL;
2747                 goto free_bus_id;
2748         }
2749
2750         status = device_add(&ctlr->dev);
2751         if (status < 0)
2752                 goto free_bus_id;
2753         dev_dbg(dev, "registered %s %s\n",
2754                         spi_controller_is_slave(ctlr) ? "slave" : "master",
2755                         dev_name(&ctlr->dev));
2756
2757         /*
2758          * If we're using a queued driver, start the queue. Note that we don't
2759          * need the queueing logic if the driver is only supporting high-level
2760          * memory operations.
2761          */
2762         if (ctlr->transfer) {
2763                 dev_info(dev, "controller is unqueued, this is deprecated\n");
2764         } else if (ctlr->transfer_one || ctlr->transfer_one_message) {
2765                 status = spi_controller_initialize_queue(ctlr);
2766                 if (status) {
2767                         device_del(&ctlr->dev);
2768                         goto free_bus_id;
2769                 }
2770         }
2771         /* add statistics */
2772         spin_lock_init(&ctlr->statistics.lock);
2773
2774         mutex_lock(&board_lock);
2775         list_add_tail(&ctlr->list, &spi_controller_list);
2776         list_for_each_entry(bi, &board_list, list)
2777                 spi_match_controller_to_boardinfo(ctlr, &bi->board_info);
2778         mutex_unlock(&board_lock);
2779
2780         /* Register devices from the device tree and ACPI */
2781         of_register_spi_devices(ctlr);
2782         acpi_register_spi_devices(ctlr);
2783         return status;
2784
2785 free_bus_id:
2786         mutex_lock(&board_lock);
2787         idr_remove(&spi_master_idr, ctlr->bus_num);
2788         mutex_unlock(&board_lock);
2789         return status;
2790 }
2791 EXPORT_SYMBOL_GPL(spi_register_controller);
2792
2793 static void devm_spi_unregister(struct device *dev, void *res)
2794 {
2795         spi_unregister_controller(*(struct spi_controller **)res);
2796 }
2797
2798 /**
2799  * devm_spi_register_controller - register managed SPI master or slave
2800  *      controller
2801  * @dev:    device managing SPI controller
2802  * @ctlr: initialized controller, originally from spi_alloc_master() or
2803  *      spi_alloc_slave()
2804  * Context: can sleep
2805  *
2806  * Register a SPI device as with spi_register_controller() which will
2807  * automatically be unregistered and freed.
2808  *
2809  * Return: zero on success, else a negative error code.
2810  */
2811 int devm_spi_register_controller(struct device *dev,
2812                                  struct spi_controller *ctlr)
2813 {
2814         struct spi_controller **ptr;
2815         int ret;
2816
2817         ptr = devres_alloc(devm_spi_unregister, sizeof(*ptr), GFP_KERNEL);
2818         if (!ptr)
2819                 return -ENOMEM;
2820
2821         ret = spi_register_controller(ctlr);
2822         if (!ret) {
2823                 *ptr = ctlr;
2824                 devres_add(dev, ptr);
2825         } else {
2826                 devres_free(ptr);
2827         }
2828
2829         return ret;
2830 }
2831 EXPORT_SYMBOL_GPL(devm_spi_register_controller);
2832
2833 static int devm_spi_match_controller(struct device *dev, void *res, void *ctlr)
2834 {
2835         return *(struct spi_controller **)res == ctlr;
2836 }
2837
2838 static int __unregister(struct device *dev, void *null)
2839 {
2840         spi_unregister_device(to_spi_device(dev));
2841         return 0;
2842 }
2843
2844 /**
2845  * spi_unregister_controller - unregister SPI master or slave controller
2846  * @ctlr: the controller being unregistered
2847  * Context: can sleep
2848  *
2849  * This call is used only by SPI controller drivers, which are the
2850  * only ones directly touching chip registers.
2851  *
2852  * This must be called from context that can sleep.
2853  *
2854  * Note that this function also drops a reference to the controller.
2855  */
2856 void spi_unregister_controller(struct spi_controller *ctlr)
2857 {
2858         struct spi_controller *found;
2859         int id = ctlr->bus_num;
2860
2861         /* Prevent addition of new devices, unregister existing ones */
2862         if (IS_ENABLED(CONFIG_SPI_DYNAMIC))
2863                 mutex_lock(&spi_add_lock);
2864
2865         device_for_each_child(&ctlr->dev, NULL, __unregister);
2866
2867         /* First make sure that this controller was ever added */
2868         mutex_lock(&board_lock);
2869         found = idr_find(&spi_master_idr, id);
2870         mutex_unlock(&board_lock);
2871         if (ctlr->queued) {
2872                 if (spi_destroy_queue(ctlr))
2873                         dev_err(&ctlr->dev, "queue remove failed\n");
2874         }
2875         mutex_lock(&board_lock);
2876         list_del(&ctlr->list);
2877         mutex_unlock(&board_lock);
2878
2879         device_del(&ctlr->dev);
2880
2881         /* Release the last reference on the controller if its driver
2882          * has not yet been converted to devm_spi_alloc_master/slave().
2883          */
2884         if (!devres_find(ctlr->dev.parent, devm_spi_release_controller,
2885                          devm_spi_match_controller, ctlr))
2886                 put_device(&ctlr->dev);
2887
2888         /* free bus id */
2889         mutex_lock(&board_lock);
2890         if (found == ctlr)
2891                 idr_remove(&spi_master_idr, id);
2892         mutex_unlock(&board_lock);
2893
2894         if (IS_ENABLED(CONFIG_SPI_DYNAMIC))
2895                 mutex_unlock(&spi_add_lock);
2896 }
2897 EXPORT_SYMBOL_GPL(spi_unregister_controller);
2898
2899 int spi_controller_suspend(struct spi_controller *ctlr)
2900 {
2901         int ret;
2902
2903         /* Basically no-ops for non-queued controllers */
2904         if (!ctlr->queued)
2905                 return 0;
2906
2907         ret = spi_stop_queue(ctlr);
2908         if (ret)
2909                 dev_err(&ctlr->dev, "queue stop failed\n");
2910
2911         return ret;
2912 }
2913 EXPORT_SYMBOL_GPL(spi_controller_suspend);
2914
2915 int spi_controller_resume(struct spi_controller *ctlr)
2916 {
2917         int ret;
2918
2919         if (!ctlr->queued)
2920                 return 0;
2921
2922         ret = spi_start_queue(ctlr);
2923         if (ret)
2924                 dev_err(&ctlr->dev, "queue restart failed\n");
2925
2926         return ret;
2927 }
2928 EXPORT_SYMBOL_GPL(spi_controller_resume);
2929
2930 static int __spi_controller_match(struct device *dev, const void *data)
2931 {
2932         struct spi_controller *ctlr;
2933         const u16 *bus_num = data;
2934
2935         ctlr = container_of(dev, struct spi_controller, dev);
2936         return ctlr->bus_num == *bus_num;
2937 }
2938
2939 /**
2940  * spi_busnum_to_master - look up master associated with bus_num
2941  * @bus_num: the master's bus number
2942  * Context: can sleep
2943  *
2944  * This call may be used with devices that are registered after
2945  * arch init time.  It returns a refcounted pointer to the relevant
2946  * spi_controller (which the caller must release), or NULL if there is
2947  * no such master registered.
2948  *
2949  * Return: the SPI master structure on success, else NULL.
2950  */
2951 struct spi_controller *spi_busnum_to_master(u16 bus_num)
2952 {
2953         struct device           *dev;
2954         struct spi_controller   *ctlr = NULL;
2955
2956         dev = class_find_device(&spi_master_class, NULL, &bus_num,
2957                                 __spi_controller_match);
2958         if (dev)
2959                 ctlr = container_of(dev, struct spi_controller, dev);
2960         /* reference got in class_find_device */
2961         return ctlr;
2962 }
2963 EXPORT_SYMBOL_GPL(spi_busnum_to_master);
2964
2965 /*-------------------------------------------------------------------------*/
2966
2967 /* Core methods for SPI resource management */
2968
2969 /**
2970  * spi_res_alloc - allocate a spi resource that is life-cycle managed
2971  *                 during the processing of a spi_message while using
2972  *                 spi_transfer_one
2973  * @spi:     the spi device for which we allocate memory
2974  * @release: the release code to execute for this resource
2975  * @size:    size to alloc and return
2976  * @gfp:     GFP allocation flags
2977  *
2978  * Return: the pointer to the allocated data
2979  *
2980  * This may get enhanced in the future to allocate from a memory pool
2981  * of the @spi_device or @spi_controller to avoid repeated allocations.
2982  */
2983 void *spi_res_alloc(struct spi_device *spi,
2984                     spi_res_release_t release,
2985                     size_t size, gfp_t gfp)
2986 {
2987         struct spi_res *sres;
2988
2989         sres = kzalloc(sizeof(*sres) + size, gfp);
2990         if (!sres)
2991                 return NULL;
2992
2993         INIT_LIST_HEAD(&sres->entry);
2994         sres->release = release;
2995
2996         return sres->data;
2997 }
2998 EXPORT_SYMBOL_GPL(spi_res_alloc);
2999
3000 /**
3001  * spi_res_free - free an spi resource
3002  * @res: pointer to the custom data of a resource
3003  *
3004  */
3005 void spi_res_free(void *res)
3006 {
3007         struct spi_res *sres = container_of(res, struct spi_res, data);
3008
3009         if (!res)
3010                 return;
3011
3012         WARN_ON(!list_empty(&sres->entry));
3013         kfree(sres);
3014 }
3015 EXPORT_SYMBOL_GPL(spi_res_free);
3016
3017 /**
3018  * spi_res_add - add a spi_res to the spi_message
3019  * @message: the spi message
3020  * @res:     the spi_resource
3021  */
3022 void spi_res_add(struct spi_message *message, void *res)
3023 {
3024         struct spi_res *sres = container_of(res, struct spi_res, data);
3025
3026         WARN_ON(!list_empty(&sres->entry));
3027         list_add_tail(&sres->entry, &message->resources);
3028 }
3029 EXPORT_SYMBOL_GPL(spi_res_add);
3030
3031 /**
3032  * spi_res_release - release all spi resources for this message
3033  * @ctlr:  the @spi_controller
3034  * @message: the @spi_message
3035  */
3036 void spi_res_release(struct spi_controller *ctlr, struct spi_message *message)
3037 {
3038         struct spi_res *res, *tmp;
3039
3040         list_for_each_entry_safe_reverse(res, tmp, &message->resources, entry) {
3041                 if (res->release)
3042                         res->release(ctlr, message, res->data);
3043
3044                 list_del(&res->entry);
3045
3046                 kfree(res);
3047         }
3048 }
3049 EXPORT_SYMBOL_GPL(spi_res_release);
3050
3051 /*-------------------------------------------------------------------------*/
3052
3053 /* Core methods for spi_message alterations */
3054
3055 static void __spi_replace_transfers_release(struct spi_controller *ctlr,
3056                                             struct spi_message *msg,
3057                                             void *res)
3058 {
3059         struct spi_replaced_transfers *rxfer = res;
3060         size_t i;
3061
3062         /* call extra callback if requested */
3063         if (rxfer->release)
3064                 rxfer->release(ctlr, msg, res);
3065
3066         /* insert replaced transfers back into the message */
3067         list_splice(&rxfer->replaced_transfers, rxfer->replaced_after);
3068
3069         /* remove the formerly inserted entries */
3070         for (i = 0; i < rxfer->inserted; i++)
3071                 list_del(&rxfer->inserted_transfers[i].transfer_list);
3072 }
3073
3074 /**
3075  * spi_replace_transfers - replace transfers with several transfers
3076  *                         and register change with spi_message.resources
3077  * @msg:           the spi_message we work upon
3078  * @xfer_first:    the first spi_transfer we want to replace
3079  * @remove:        number of transfers to remove
3080  * @insert:        the number of transfers we want to insert instead
3081  * @release:       extra release code necessary in some circumstances
3082  * @extradatasize: extra data to allocate (with alignment guarantees
3083  *                 of struct @spi_transfer)
3084  * @gfp:           gfp flags
3085  *
3086  * Returns: pointer to @spi_replaced_transfers,
3087  *          PTR_ERR(...) in case of errors.
3088  */
3089 struct spi_replaced_transfers *spi_replace_transfers(
3090         struct spi_message *msg,
3091         struct spi_transfer *xfer_first,
3092         size_t remove,
3093         size_t insert,
3094         spi_replaced_release_t release,
3095         size_t extradatasize,
3096         gfp_t gfp)
3097 {
3098         struct spi_replaced_transfers *rxfer;
3099         struct spi_transfer *xfer;
3100         size_t i;
3101
3102         /* allocate the structure using spi_res */
3103         rxfer = spi_res_alloc(msg->spi, __spi_replace_transfers_release,
3104                               struct_size(rxfer, inserted_transfers, insert)
3105                               + extradatasize,
3106                               gfp);
3107         if (!rxfer)
3108                 return ERR_PTR(-ENOMEM);
3109
3110         /* the release code to invoke before running the generic release */
3111         rxfer->release = release;
3112
3113         /* assign extradata */
3114         if (extradatasize)
3115                 rxfer->extradata =
3116                         &rxfer->inserted_transfers[insert];
3117
3118         /* init the replaced_transfers list */
3119         INIT_LIST_HEAD(&rxfer->replaced_transfers);
3120
3121         /* assign the list_entry after which we should reinsert
3122          * the @replaced_transfers - it may be spi_message.messages!
3123          */
3124         rxfer->replaced_after = xfer_first->transfer_list.prev;
3125
3126         /* remove the requested number of transfers */
3127         for (i = 0; i < remove; i++) {
3128                 /* if the entry after replaced_after it is msg->transfers
3129                  * then we have been requested to remove more transfers
3130                  * than are in the list
3131                  */
3132                 if (rxfer->replaced_after->next == &msg->transfers) {
3133                         dev_err(&msg->spi->dev,
3134                                 "requested to remove more spi_transfers than are available\n");
3135                         /* insert replaced transfers back into the message */
3136                         list_splice(&rxfer->replaced_transfers,
3137                                     rxfer->replaced_after);
3138
3139                         /* free the spi_replace_transfer structure */
3140                         spi_res_free(rxfer);
3141
3142                         /* and return with an error */
3143                         return ERR_PTR(-EINVAL);
3144                 }
3145
3146                 /* remove the entry after replaced_after from list of
3147                  * transfers and add it to list of replaced_transfers
3148                  */
3149                 list_move_tail(rxfer->replaced_after->next,
3150                                &rxfer->replaced_transfers);
3151         }
3152
3153         /* create copy of the given xfer with identical settings
3154          * based on the first transfer to get removed
3155          */
3156         for (i = 0; i < insert; i++) {
3157                 /* we need to run in reverse order */
3158                 xfer = &rxfer->inserted_transfers[insert - 1 - i];
3159
3160                 /* copy all spi_transfer data */
3161                 memcpy(xfer, xfer_first, sizeof(*xfer));
3162
3163                 /* add to list */
3164                 list_add(&xfer->transfer_list, rxfer->replaced_after);
3165
3166                 /* clear cs_change and delay for all but the last */
3167                 if (i) {
3168                         xfer->cs_change = false;
3169                         xfer->delay_usecs = 0;
3170                         xfer->delay.value = 0;
3171                 }
3172         }
3173
3174         /* set up inserted */
3175         rxfer->inserted = insert;
3176
3177         /* and register it with spi_res/spi_message */
3178         spi_res_add(msg, rxfer);
3179
3180         return rxfer;
3181 }
3182 EXPORT_SYMBOL_GPL(spi_replace_transfers);
3183
3184 static int __spi_split_transfer_maxsize(struct spi_controller *ctlr,
3185                                         struct spi_message *msg,
3186                                         struct spi_transfer **xferp,
3187                                         size_t maxsize,
3188                                         gfp_t gfp)
3189 {
3190         struct spi_transfer *xfer = *xferp, *xfers;
3191         struct spi_replaced_transfers *srt;
3192         size_t offset;
3193         size_t count, i;
3194
3195         /* calculate how many we have to replace */
3196         count = DIV_ROUND_UP(xfer->len, maxsize);
3197
3198         /* create replacement */
3199         srt = spi_replace_transfers(msg, xfer, 1, count, NULL, 0, gfp);
3200         if (IS_ERR(srt))
3201                 return PTR_ERR(srt);
3202         xfers = srt->inserted_transfers;
3203
3204         /* now handle each of those newly inserted spi_transfers
3205          * note that the replacements spi_transfers all are preset
3206          * to the same values as *xferp, so tx_buf, rx_buf and len
3207          * are all identical (as well as most others)
3208          * so we just have to fix up len and the pointers.
3209          *
3210          * this also includes support for the depreciated
3211          * spi_message.is_dma_mapped interface
3212          */
3213
3214         /* the first transfer just needs the length modified, so we
3215          * run it outside the loop
3216          */
3217         xfers[0].len = min_t(size_t, maxsize, xfer[0].len);
3218
3219         /* all the others need rx_buf/tx_buf also set */
3220         for (i = 1, offset = maxsize; i < count; offset += maxsize, i++) {
3221                 /* update rx_buf, tx_buf and dma */
3222                 if (xfers[i].rx_buf)
3223                         xfers[i].rx_buf += offset;
3224                 if (xfers[i].rx_dma)
3225                         xfers[i].rx_dma += offset;
3226                 if (xfers[i].tx_buf)
3227                         xfers[i].tx_buf += offset;
3228                 if (xfers[i].tx_dma)
3229                         xfers[i].tx_dma += offset;
3230
3231                 /* update length */
3232                 xfers[i].len = min(maxsize, xfers[i].len - offset);
3233         }
3234
3235         /* we set up xferp to the last entry we have inserted,
3236          * so that we skip those already split transfers
3237          */
3238         *xferp = &xfers[count - 1];
3239
3240         /* increment statistics counters */
3241         SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics,
3242                                        transfers_split_maxsize);
3243         SPI_STATISTICS_INCREMENT_FIELD(&msg->spi->statistics,
3244                                        transfers_split_maxsize);
3245
3246         return 0;
3247 }
3248
3249 /**
3250  * spi_split_transfers_maxsize - split spi transfers into multiple transfers
3251  *                               when an individual transfer exceeds a
3252  *                               certain size
3253  * @ctlr:    the @spi_controller for this transfer
3254  * @msg:   the @spi_message to transform
3255  * @maxsize:  the maximum when to apply this
3256  * @gfp: GFP allocation flags
3257  *
3258  * Return: status of transformation
3259  */
3260 int spi_split_transfers_maxsize(struct spi_controller *ctlr,
3261                                 struct spi_message *msg,
3262                                 size_t maxsize,
3263                                 gfp_t gfp)
3264 {
3265         struct spi_transfer *xfer;
3266         int ret;
3267
3268         /* iterate over the transfer_list,
3269          * but note that xfer is advanced to the last transfer inserted
3270          * to avoid checking sizes again unnecessarily (also xfer does
3271          * potentiall belong to a different list by the time the
3272          * replacement has happened
3273          */
3274         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
3275                 if (xfer->len > maxsize) {
3276                         ret = __spi_split_transfer_maxsize(ctlr, msg, &xfer,
3277                                                            maxsize, gfp);
3278                         if (ret)
3279                                 return ret;
3280                 }
3281         }
3282
3283         return 0;
3284 }
3285 EXPORT_SYMBOL_GPL(spi_split_transfers_maxsize);
3286
3287 /*-------------------------------------------------------------------------*/
3288
3289 /* Core methods for SPI controller protocol drivers.  Some of the
3290  * other core methods are currently defined as inline functions.
3291  */
3292
3293 static int __spi_validate_bits_per_word(struct spi_controller *ctlr,
3294                                         u8 bits_per_word)
3295 {
3296         if (ctlr->bits_per_word_mask) {
3297                 /* Only 32 bits fit in the mask */
3298                 if (bits_per_word > 32)
3299                         return -EINVAL;
3300                 if (!(ctlr->bits_per_word_mask & SPI_BPW_MASK(bits_per_word)))
3301                         return -EINVAL;
3302         }
3303
3304         return 0;
3305 }
3306
3307 /**
3308  * spi_setup - setup SPI mode and clock rate
3309  * @spi: the device whose settings are being modified
3310  * Context: can sleep, and no requests are queued to the device
3311  *
3312  * SPI protocol drivers may need to update the transfer mode if the
3313  * device doesn't work with its default.  They may likewise need
3314  * to update clock rates or word sizes from initial values.  This function
3315  * changes those settings, and must be called from a context that can sleep.
3316  * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
3317  * effect the next time the device is selected and data is transferred to
3318  * or from it.  When this function returns, the spi device is deselected.
3319  *
3320  * Note that this call will fail if the protocol driver specifies an option
3321  * that the underlying controller or its driver does not support.  For
3322  * example, not all hardware supports wire transfers using nine bit words,
3323  * LSB-first wire encoding, or active-high chipselects.
3324  *
3325  * Return: zero on success, else a negative error code.
3326  */
3327 int spi_setup(struct spi_device *spi)
3328 {
3329         unsigned        bad_bits, ugly_bits;
3330         int             status;
3331
3332         /* check mode to prevent that DUAL and QUAD set at the same time
3333          */
3334         if (((spi->mode & SPI_TX_DUAL) && (spi->mode & SPI_TX_QUAD)) ||
3335                 ((spi->mode & SPI_RX_DUAL) && (spi->mode & SPI_RX_QUAD))) {
3336                 dev_err(&spi->dev,
3337                 "setup: can not select dual and quad at the same time\n");
3338                 return -EINVAL;
3339         }
3340         /* if it is SPI_3WIRE mode, DUAL and QUAD should be forbidden
3341          */
3342         if ((spi->mode & SPI_3WIRE) && (spi->mode &
3343                 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_TX_OCTAL |
3344                  SPI_RX_DUAL | SPI_RX_QUAD | SPI_RX_OCTAL)))
3345                 return -EINVAL;
3346         /* help drivers fail *cleanly* when they need options
3347          * that aren't supported with their current controller
3348          * SPI_CS_WORD has a fallback software implementation,
3349          * so it is ignored here.
3350          */
3351         bad_bits = spi->mode & ~(spi->controller->mode_bits | SPI_CS_WORD);
3352         /* nothing prevents from working with active-high CS in case if it
3353          * is driven by GPIO.
3354          */
3355         if (gpio_is_valid(spi->cs_gpio))
3356                 bad_bits &= ~SPI_CS_HIGH;
3357         ugly_bits = bad_bits &
3358                     (SPI_TX_DUAL | SPI_TX_QUAD | SPI_TX_OCTAL |
3359                      SPI_RX_DUAL | SPI_RX_QUAD | SPI_RX_OCTAL);
3360         if (ugly_bits) {
3361                 dev_warn(&spi->dev,
3362                          "setup: ignoring unsupported mode bits %x\n",
3363                          ugly_bits);
3364                 spi->mode &= ~ugly_bits;
3365                 bad_bits &= ~ugly_bits;
3366         }
3367         if (bad_bits) {
3368                 dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
3369                         bad_bits);
3370                 return -EINVAL;
3371         }
3372
3373         if (!spi->bits_per_word)
3374                 spi->bits_per_word = 8;
3375
3376         status = __spi_validate_bits_per_word(spi->controller,
3377                                               spi->bits_per_word);
3378         if (status)
3379                 return status;
3380
3381         if (!spi->max_speed_hz ||
3382             spi->max_speed_hz > spi->controller->max_speed_hz)
3383                 spi->max_speed_hz = spi->controller->max_speed_hz;
3384
3385         mutex_lock(&spi->controller->io_mutex);
3386
3387         if (spi->controller->setup)
3388                 status = spi->controller->setup(spi);
3389
3390         if (spi->controller->auto_runtime_pm && spi->controller->set_cs) {
3391                 status = pm_runtime_get_sync(spi->controller->dev.parent);
3392                 if (status < 0) {
3393                         mutex_unlock(&spi->controller->io_mutex);
3394                         pm_runtime_put_noidle(spi->controller->dev.parent);
3395                         dev_err(&spi->controller->dev, "Failed to power device: %d\n",
3396                                 status);
3397                         return status;
3398                 }
3399
3400                 /*
3401                  * We do not want to return positive value from pm_runtime_get,
3402                  * there are many instances of devices calling spi_setup() and
3403                  * checking for a non-zero return value instead of a negative
3404                  * return value.
3405                  */
3406                 status = 0;
3407
3408                 spi_set_cs(spi, false);
3409                 pm_runtime_mark_last_busy(spi->controller->dev.parent);
3410                 pm_runtime_put_autosuspend(spi->controller->dev.parent);
3411         } else {
3412                 spi_set_cs(spi, false);
3413         }
3414
3415         mutex_unlock(&spi->controller->io_mutex);
3416
3417         if (spi->rt && !spi->controller->rt) {
3418                 spi->controller->rt = true;
3419                 spi_set_thread_rt(spi->controller);
3420         }
3421
3422         dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
3423                         (int) (spi->mode & (SPI_CPOL | SPI_CPHA)),
3424                         (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
3425                         (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
3426                         (spi->mode & SPI_3WIRE) ? "3wire, " : "",
3427                         (spi->mode & SPI_LOOP) ? "loopback, " : "",
3428                         spi->bits_per_word, spi->max_speed_hz,
3429                         status);
3430
3431         return status;
3432 }
3433 EXPORT_SYMBOL_GPL(spi_setup);
3434
3435 /**
3436  * spi_set_cs_timing - configure CS setup, hold, and inactive delays
3437  * @spi: the device that requires specific CS timing configuration
3438  * @setup: CS setup time specified via @spi_delay
3439  * @hold: CS hold time specified via @spi_delay
3440  * @inactive: CS inactive delay between transfers specified via @spi_delay
3441  *
3442  * Return: zero on success, else a negative error code.
3443  */
3444 int spi_set_cs_timing(struct spi_device *spi, struct spi_delay *setup,
3445                       struct spi_delay *hold, struct spi_delay *inactive)
3446 {
3447         size_t len;
3448
3449         if (spi->controller->set_cs_timing)
3450                 return spi->controller->set_cs_timing(spi, setup, hold,
3451                                                       inactive);
3452
3453         if ((setup && setup->unit == SPI_DELAY_UNIT_SCK) ||
3454             (hold && hold->unit == SPI_DELAY_UNIT_SCK) ||
3455             (inactive && inactive->unit == SPI_DELAY_UNIT_SCK)) {
3456                 dev_err(&spi->dev,
3457                         "Clock-cycle delays for CS not supported in SW mode\n");
3458                 return -ENOTSUPP;
3459         }
3460
3461         len = sizeof(struct spi_delay);
3462
3463         /* copy delays to controller */
3464         if (setup)
3465                 memcpy(&spi->controller->cs_setup, setup, len);
3466         else
3467                 memset(&spi->controller->cs_setup, 0, len);
3468
3469         if (hold)
3470                 memcpy(&spi->controller->cs_hold, hold, len);
3471         else
3472                 memset(&spi->controller->cs_hold, 0, len);
3473
3474         if (inactive)
3475                 memcpy(&spi->controller->cs_inactive, inactive, len);
3476         else
3477                 memset(&spi->controller->cs_inactive, 0, len);
3478
3479         return 0;
3480 }
3481 EXPORT_SYMBOL_GPL(spi_set_cs_timing);
3482
3483 static int _spi_xfer_word_delay_update(struct spi_transfer *xfer,
3484                                        struct spi_device *spi)
3485 {
3486         int delay1, delay2;
3487
3488         delay1 = spi_delay_to_ns(&xfer->word_delay, xfer);
3489         if (delay1 < 0)
3490                 return delay1;
3491
3492         delay2 = spi_delay_to_ns(&spi->word_delay, xfer);
3493         if (delay2 < 0)
3494                 return delay2;
3495
3496         if (delay1 < delay2)
3497                 memcpy(&xfer->word_delay, &spi->word_delay,
3498                        sizeof(xfer->word_delay));
3499
3500         return 0;
3501 }
3502
3503 static int __spi_validate(struct spi_device *spi, struct spi_message *message)
3504 {
3505         struct spi_controller *ctlr = spi->controller;
3506         struct spi_transfer *xfer;
3507         int w_size;
3508
3509         if (list_empty(&message->transfers))
3510                 return -EINVAL;
3511
3512         /* If an SPI controller does not support toggling the CS line on each
3513          * transfer (indicated by the SPI_CS_WORD flag) or we are using a GPIO
3514          * for the CS line, we can emulate the CS-per-word hardware function by
3515          * splitting transfers into one-word transfers and ensuring that
3516          * cs_change is set for each transfer.
3517          */
3518         if ((spi->mode & SPI_CS_WORD) && (!(ctlr->mode_bits & SPI_CS_WORD) ||
3519                                           spi->cs_gpiod ||
3520                                           gpio_is_valid(spi->cs_gpio))) {
3521                 size_t maxsize;
3522                 int ret;
3523
3524                 maxsize = (spi->bits_per_word + 7) / 8;
3525
3526                 /* spi_split_transfers_maxsize() requires message->spi */
3527                 message->spi = spi;
3528
3529                 ret = spi_split_transfers_maxsize(ctlr, message, maxsize,
3530                                                   GFP_KERNEL);
3531                 if (ret)
3532                         return ret;
3533
3534                 list_for_each_entry(xfer, &message->transfers, transfer_list) {
3535                         /* don't change cs_change on the last entry in the list */
3536                         if (list_is_last(&xfer->transfer_list, &message->transfers))
3537                                 break;
3538                         xfer->cs_change = 1;
3539                 }
3540         }
3541
3542         /* Half-duplex links include original MicroWire, and ones with
3543          * only one data pin like SPI_3WIRE (switches direction) or where
3544          * either MOSI or MISO is missing.  They can also be caused by
3545          * software limitations.
3546          */
3547         if ((ctlr->flags & SPI_CONTROLLER_HALF_DUPLEX) ||
3548             (spi->mode & SPI_3WIRE)) {
3549                 unsigned flags = ctlr->flags;
3550
3551                 list_for_each_entry(xfer, &message->transfers, transfer_list) {
3552                         if (xfer->rx_buf && xfer->tx_buf)
3553                                 return -EINVAL;
3554                         if ((flags & SPI_CONTROLLER_NO_TX) && xfer->tx_buf)
3555                                 return -EINVAL;
3556                         if ((flags & SPI_CONTROLLER_NO_RX) && xfer->rx_buf)
3557                                 return -EINVAL;
3558                 }
3559         }
3560
3561         /**
3562          * Set transfer bits_per_word and max speed as spi device default if
3563          * it is not set for this transfer.
3564          * Set transfer tx_nbits and rx_nbits as single transfer default
3565          * (SPI_NBITS_SINGLE) if it is not set for this transfer.
3566          * Ensure transfer word_delay is at least as long as that required by
3567          * device itself.
3568          */
3569         message->frame_length = 0;
3570         list_for_each_entry(xfer, &message->transfers, transfer_list) {
3571                 xfer->effective_speed_hz = 0;
3572                 message->frame_length += xfer->len;
3573                 if (!xfer->bits_per_word)
3574                         xfer->bits_per_word = spi->bits_per_word;
3575
3576                 if (!xfer->speed_hz)
3577                         xfer->speed_hz = spi->max_speed_hz;
3578
3579                 if (ctlr->max_speed_hz && xfer->speed_hz > ctlr->max_speed_hz)
3580                         xfer->speed_hz = ctlr->max_speed_hz;
3581
3582                 if (__spi_validate_bits_per_word(ctlr, xfer->bits_per_word))
3583                         return -EINVAL;
3584
3585                 /*
3586                  * SPI transfer length should be multiple of SPI word size
3587                  * where SPI word size should be power-of-two multiple
3588                  */
3589                 if (xfer->bits_per_word <= 8)
3590                         w_size = 1;
3591                 else if (xfer->bits_per_word <= 16)
3592                         w_size = 2;
3593                 else
3594                         w_size = 4;
3595
3596                 /* No partial transfers accepted */
3597                 if (xfer->len % w_size)
3598                         return -EINVAL;
3599
3600                 if (xfer->speed_hz && ctlr->min_speed_hz &&
3601                     xfer->speed_hz < ctlr->min_speed_hz)
3602                         return -EINVAL;
3603
3604                 if (xfer->tx_buf && !xfer->tx_nbits)
3605                         xfer->tx_nbits = SPI_NBITS_SINGLE;
3606                 if (xfer->rx_buf && !xfer->rx_nbits)
3607                         xfer->rx_nbits = SPI_NBITS_SINGLE;
3608                 /* check transfer tx/rx_nbits:
3609                  * 1. check the value matches one of single, dual and quad
3610                  * 2. check tx/rx_nbits match the mode in spi_device
3611                  */
3612                 if (xfer->tx_buf) {
3613                         if (xfer->tx_nbits != SPI_NBITS_SINGLE &&
3614                                 xfer->tx_nbits != SPI_NBITS_DUAL &&
3615                                 xfer->tx_nbits != SPI_NBITS_QUAD)
3616                                 return -EINVAL;
3617                         if ((xfer->tx_nbits == SPI_NBITS_DUAL) &&
3618                                 !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
3619                                 return -EINVAL;
3620                         if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
3621                                 !(spi->mode & SPI_TX_QUAD))
3622                                 return -EINVAL;
3623                 }
3624                 /* check transfer rx_nbits */
3625                 if (xfer->rx_buf) {
3626                         if (xfer->rx_nbits != SPI_NBITS_SINGLE &&
3627                                 xfer->rx_nbits != SPI_NBITS_DUAL &&
3628                                 xfer->rx_nbits != SPI_NBITS_QUAD)
3629                                 return -EINVAL;
3630                         if ((xfer->rx_nbits == SPI_NBITS_DUAL) &&
3631                                 !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
3632                                 return -EINVAL;
3633                         if ((xfer->rx_nbits == SPI_NBITS_QUAD) &&
3634                                 !(spi->mode & SPI_RX_QUAD))
3635                                 return -EINVAL;
3636                 }
3637
3638                 if (_spi_xfer_word_delay_update(xfer, spi))
3639                         return -EINVAL;
3640         }
3641
3642         message->status = -EINPROGRESS;
3643
3644         return 0;
3645 }
3646
3647 static int __spi_async(struct spi_device *spi, struct spi_message *message)
3648 {
3649         struct spi_controller *ctlr = spi->controller;
3650         struct spi_transfer *xfer;
3651
3652         /*
3653          * Some controllers do not support doing regular SPI transfers. Return
3654          * ENOTSUPP when this is the case.
3655          */
3656         if (!ctlr->transfer)
3657                 return -ENOTSUPP;
3658
3659         message->spi = spi;
3660
3661         SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics, spi_async);
3662         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_async);
3663
3664         trace_spi_message_submit(message);
3665
3666         if (!ctlr->ptp_sts_supported) {
3667                 list_for_each_entry(xfer, &message->transfers, transfer_list) {
3668                         xfer->ptp_sts_word_pre = 0;
3669                         ptp_read_system_prets(xfer->ptp_sts);
3670                 }
3671         }
3672
3673         return ctlr->transfer(spi, message);
3674 }
3675
3676 /**
3677  * spi_async - asynchronous SPI transfer
3678  * @spi: device with which data will be exchanged
3679  * @message: describes the data transfers, including completion callback
3680  * Context: any (irqs may be blocked, etc)
3681  *
3682  * This call may be used in_irq and other contexts which can't sleep,
3683  * as well as from task contexts which can sleep.
3684  *
3685  * The completion callback is invoked in a context which can't sleep.
3686  * Before that invocation, the value of message->status is undefined.
3687  * When the callback is issued, message->status holds either zero (to
3688  * indicate complete success) or a negative error code.  After that
3689  * callback returns, the driver which issued the transfer request may
3690  * deallocate the associated memory; it's no longer in use by any SPI
3691  * core or controller driver code.
3692  *
3693  * Note that although all messages to a spi_device are handled in
3694  * FIFO order, messages may go to different devices in other orders.
3695  * Some device might be higher priority, or have various "hard" access
3696  * time requirements, for example.
3697  *
3698  * On detection of any fault during the transfer, processing of
3699  * the entire message is aborted, and the device is deselected.
3700  * Until returning from the associated message completion callback,
3701  * no other spi_message queued to that device will be processed.
3702  * (This rule applies equally to all the synchronous transfer calls,
3703  * which are wrappers around this core asynchronous primitive.)
3704  *
3705  * Return: zero on success, else a negative error code.
3706  */
3707 int spi_async(struct spi_device *spi, struct spi_message *message)
3708 {
3709         struct spi_controller *ctlr = spi->controller;
3710         int ret;
3711         unsigned long flags;
3712
3713         ret = __spi_validate(spi, message);
3714         if (ret != 0)
3715                 return ret;
3716
3717         spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
3718
3719         if (ctlr->bus_lock_flag)
3720                 ret = -EBUSY;
3721         else
3722                 ret = __spi_async(spi, message);
3723
3724         spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3725
3726         return ret;
3727 }
3728 EXPORT_SYMBOL_GPL(spi_async);
3729
3730 /**
3731  * spi_async_locked - version of spi_async with exclusive bus usage
3732  * @spi: device with which data will be exchanged
3733  * @message: describes the data transfers, including completion callback
3734  * Context: any (irqs may be blocked, etc)
3735  *
3736  * This call may be used in_irq and other contexts which can't sleep,
3737  * as well as from task contexts which can sleep.
3738  *
3739  * The completion callback is invoked in a context which can't sleep.
3740  * Before that invocation, the value of message->status is undefined.
3741  * When the callback is issued, message->status holds either zero (to
3742  * indicate complete success) or a negative error code.  After that
3743  * callback returns, the driver which issued the transfer request may
3744  * deallocate the associated memory; it's no longer in use by any SPI
3745  * core or controller driver code.
3746  *
3747  * Note that although all messages to a spi_device are handled in
3748  * FIFO order, messages may go to different devices in other orders.
3749  * Some device might be higher priority, or have various "hard" access
3750  * time requirements, for example.
3751  *
3752  * On detection of any fault during the transfer, processing of
3753  * the entire message is aborted, and the device is deselected.
3754  * Until returning from the associated message completion callback,
3755  * no other spi_message queued to that device will be processed.
3756  * (This rule applies equally to all the synchronous transfer calls,
3757  * which are wrappers around this core asynchronous primitive.)
3758  *
3759  * Return: zero on success, else a negative error code.
3760  */
3761 int spi_async_locked(struct spi_device *spi, struct spi_message *message)
3762 {
3763         struct spi_controller *ctlr = spi->controller;
3764         int ret;
3765         unsigned long flags;
3766
3767         ret = __spi_validate(spi, message);
3768         if (ret != 0)
3769                 return ret;
3770
3771         spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
3772
3773         ret = __spi_async(spi, message);
3774
3775         spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3776
3777         return ret;
3778
3779 }
3780 EXPORT_SYMBOL_GPL(spi_async_locked);
3781
3782 /*-------------------------------------------------------------------------*/
3783
3784 /* Utility methods for SPI protocol drivers, layered on
3785  * top of the core.  Some other utility methods are defined as
3786  * inline functions.
3787  */
3788
3789 static void spi_complete(void *arg)
3790 {
3791         complete(arg);
3792 }
3793
3794 static int __spi_sync(struct spi_device *spi, struct spi_message *message)
3795 {
3796         DECLARE_COMPLETION_ONSTACK(done);
3797         int status;
3798         struct spi_controller *ctlr = spi->controller;
3799         unsigned long flags;
3800
3801         status = __spi_validate(spi, message);
3802         if (status != 0)
3803                 return status;
3804
3805         message->complete = spi_complete;
3806         message->context = &done;
3807         message->spi = spi;
3808
3809         SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics, spi_sync);
3810         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_sync);
3811
3812         /* If we're not using the legacy transfer method then we will
3813          * try to transfer in the calling context so special case.
3814          * This code would be less tricky if we could remove the
3815          * support for driver implemented message queues.
3816          */
3817         if (ctlr->transfer == spi_queued_transfer) {
3818                 spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
3819
3820                 trace_spi_message_submit(message);
3821
3822                 status = __spi_queued_transfer(spi, message, false);
3823
3824                 spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3825         } else {
3826                 status = spi_async_locked(spi, message);
3827         }
3828
3829         if (status == 0) {
3830                 /* Push out the messages in the calling context if we
3831                  * can.
3832                  */
3833                 if (ctlr->transfer == spi_queued_transfer) {
3834                         SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics,
3835                                                        spi_sync_immediate);
3836                         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics,
3837                                                        spi_sync_immediate);
3838                         __spi_pump_messages(ctlr, false);
3839                 }
3840
3841                 wait_for_completion(&done);
3842                 status = message->status;
3843         }
3844         message->context = NULL;
3845         return status;
3846 }
3847
3848 /**
3849  * spi_sync - blocking/synchronous SPI data transfers
3850  * @spi: device with which data will be exchanged
3851  * @message: describes the data transfers
3852  * Context: can sleep
3853  *
3854  * This call may only be used from a context that may sleep.  The sleep
3855  * is non-interruptible, and has no timeout.  Low-overhead controller
3856  * drivers may DMA directly into and out of the message buffers.
3857  *
3858  * Note that the SPI device's chip select is active during the message,
3859  * and then is normally disabled between messages.  Drivers for some
3860  * frequently-used devices may want to minimize costs of selecting a chip,
3861  * by leaving it selected in anticipation that the next message will go
3862  * to the same chip.  (That may increase power usage.)
3863  *
3864  * Also, the caller is guaranteeing that the memory associated with the
3865  * message will not be freed before this call returns.
3866  *
3867  * Return: zero on success, else a negative error code.
3868  */
3869 int spi_sync(struct spi_device *spi, struct spi_message *message)
3870 {
3871         int ret;
3872
3873         mutex_lock(&spi->controller->bus_lock_mutex);
3874         ret = __spi_sync(spi, message);
3875         mutex_unlock(&spi->controller->bus_lock_mutex);
3876
3877         return ret;
3878 }
3879 EXPORT_SYMBOL_GPL(spi_sync);
3880
3881 /**
3882  * spi_sync_locked - version of spi_sync with exclusive bus usage
3883  * @spi: device with which data will be exchanged
3884  * @message: describes the data transfers
3885  * Context: can sleep
3886  *
3887  * This call may only be used from a context that may sleep.  The sleep
3888  * is non-interruptible, and has no timeout.  Low-overhead controller
3889  * drivers may DMA directly into and out of the message buffers.
3890  *
3891  * This call should be used by drivers that require exclusive access to the
3892  * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
3893  * be released by a spi_bus_unlock call when the exclusive access is over.
3894  *
3895  * Return: zero on success, else a negative error code.
3896  */
3897 int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
3898 {
3899         return __spi_sync(spi, message);
3900 }
3901 EXPORT_SYMBOL_GPL(spi_sync_locked);
3902
3903 /**
3904  * spi_bus_lock - obtain a lock for exclusive SPI bus usage
3905  * @ctlr: SPI bus master that should be locked for exclusive bus access
3906  * Context: can sleep
3907  *
3908  * This call may only be used from a context that may sleep.  The sleep
3909  * is non-interruptible, and has no timeout.
3910  *
3911  * This call should be used by drivers that require exclusive access to the
3912  * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
3913  * exclusive access is over. Data transfer must be done by spi_sync_locked
3914  * and spi_async_locked calls when the SPI bus lock is held.
3915  *
3916  * Return: always zero.
3917  */
3918 int spi_bus_lock(struct spi_controller *ctlr)
3919 {
3920         unsigned long flags;
3921
3922         mutex_lock(&ctlr->bus_lock_mutex);
3923
3924         spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
3925         ctlr->bus_lock_flag = 1;
3926         spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3927
3928         /* mutex remains locked until spi_bus_unlock is called */
3929
3930         return 0;
3931 }
3932 EXPORT_SYMBOL_GPL(spi_bus_lock);
3933
3934 /**
3935  * spi_bus_unlock - release the lock for exclusive SPI bus usage
3936  * @ctlr: SPI bus master that was locked for exclusive bus access
3937  * Context: can sleep
3938  *
3939  * This call may only be used from a context that may sleep.  The sleep
3940  * is non-interruptible, and has no timeout.
3941  *
3942  * This call releases an SPI bus lock previously obtained by an spi_bus_lock
3943  * call.
3944  *
3945  * Return: always zero.
3946  */
3947 int spi_bus_unlock(struct spi_controller *ctlr)
3948 {
3949         ctlr->bus_lock_flag = 0;
3950
3951         mutex_unlock(&ctlr->bus_lock_mutex);
3952
3953         return 0;
3954 }
3955 EXPORT_SYMBOL_GPL(spi_bus_unlock);
3956
3957 /* portable code must never pass more than 32 bytes */
3958 #define SPI_BUFSIZ      max(32, SMP_CACHE_BYTES)
3959
3960 static u8       *buf;
3961
3962 /**
3963  * spi_write_then_read - SPI synchronous write followed by read
3964  * @spi: device with which data will be exchanged
3965  * @txbuf: data to be written (need not be dma-safe)
3966  * @n_tx: size of txbuf, in bytes
3967  * @rxbuf: buffer into which data will be read (need not be dma-safe)
3968  * @n_rx: size of rxbuf, in bytes
3969  * Context: can sleep
3970  *
3971  * This performs a half duplex MicroWire style transaction with the
3972  * device, sending txbuf and then reading rxbuf.  The return value
3973  * is zero for success, else a negative errno status code.
3974  * This call may only be used from a context that may sleep.
3975  *
3976  * Parameters to this routine are always copied using a small buffer.
3977  * Performance-sensitive or bulk transfer code should instead use
3978  * spi_{async,sync}() calls with dma-safe buffers.
3979  *
3980  * Return: zero on success, else a negative error code.
3981  */
3982 int spi_write_then_read(struct spi_device *spi,
3983                 const void *txbuf, unsigned n_tx,
3984                 void *rxbuf, unsigned n_rx)
3985 {
3986         static DEFINE_MUTEX(lock);
3987
3988         int                     status;
3989         struct spi_message      message;
3990         struct spi_transfer     x[2];
3991         u8                      *local_buf;
3992
3993         /* Use preallocated DMA-safe buffer if we can.  We can't avoid
3994          * copying here, (as a pure convenience thing), but we can
3995          * keep heap costs out of the hot path unless someone else is
3996          * using the pre-allocated buffer or the transfer is too large.
3997          */
3998         if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) {
3999                 local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx),
4000                                     GFP_KERNEL | GFP_DMA);
4001                 if (!local_buf)
4002                         return -ENOMEM;
4003         } else {
4004                 local_buf = buf;
4005         }
4006
4007         spi_message_init(&message);
4008         memset(x, 0, sizeof(x));
4009         if (n_tx) {
4010                 x[0].len = n_tx;
4011                 spi_message_add_tail(&x[0], &message);
4012         }
4013         if (n_rx) {
4014                 x[1].len = n_rx;
4015                 spi_message_add_tail(&x[1], &message);
4016         }
4017
4018         memcpy(local_buf, txbuf, n_tx);
4019         x[0].tx_buf = local_buf;
4020         x[1].rx_buf = local_buf + n_tx;
4021
4022         /* do the i/o */
4023         status = spi_sync(spi, &message);
4024         if (status == 0)
4025                 memcpy(rxbuf, x[1].rx_buf, n_rx);
4026
4027         if (x[0].tx_buf == buf)
4028                 mutex_unlock(&lock);
4029         else
4030                 kfree(local_buf);
4031
4032         return status;
4033 }
4034 EXPORT_SYMBOL_GPL(spi_write_then_read);
4035
4036 /*-------------------------------------------------------------------------*/
4037
4038 #if IS_ENABLED(CONFIG_OF)
4039 /* must call put_device() when done with returned spi_device device */
4040 struct spi_device *of_find_spi_device_by_node(struct device_node *node)
4041 {
4042         struct device *dev = bus_find_device_by_of_node(&spi_bus_type, node);
4043
4044         return dev ? to_spi_device(dev) : NULL;
4045 }
4046 EXPORT_SYMBOL_GPL(of_find_spi_device_by_node);
4047 #endif /* IS_ENABLED(CONFIG_OF) */
4048
4049 #if IS_ENABLED(CONFIG_OF_DYNAMIC)
4050 /* the spi controllers are not using spi_bus, so we find it with another way */
4051 static struct spi_controller *of_find_spi_controller_by_node(struct device_node *node)
4052 {
4053         struct device *dev;
4054
4055         dev = class_find_device_by_of_node(&spi_master_class, node);
4056         if (!dev && IS_ENABLED(CONFIG_SPI_SLAVE))
4057                 dev = class_find_device_by_of_node(&spi_slave_class, node);
4058         if (!dev)
4059                 return NULL;
4060
4061         /* reference got in class_find_device */
4062         return container_of(dev, struct spi_controller, dev);
4063 }
4064
4065 static int of_spi_notify(struct notifier_block *nb, unsigned long action,
4066                          void *arg)
4067 {
4068         struct of_reconfig_data *rd = arg;
4069         struct spi_controller *ctlr;
4070         struct spi_device *spi;
4071
4072         switch (of_reconfig_get_state_change(action, arg)) {
4073         case OF_RECONFIG_CHANGE_ADD:
4074                 ctlr = of_find_spi_controller_by_node(rd->dn->parent);
4075                 if (ctlr == NULL)
4076                         return NOTIFY_OK;       /* not for us */
4077
4078                 if (of_node_test_and_set_flag(rd->dn, OF_POPULATED)) {
4079                         put_device(&ctlr->dev);
4080                         return NOTIFY_OK;
4081                 }
4082
4083                 spi = of_register_spi_device(ctlr, rd->dn);
4084                 put_device(&ctlr->dev);
4085
4086                 if (IS_ERR(spi)) {
4087                         pr_err("%s: failed to create for '%pOF'\n",
4088                                         __func__, rd->dn);
4089                         of_node_clear_flag(rd->dn, OF_POPULATED);
4090                         return notifier_from_errno(PTR_ERR(spi));
4091                 }
4092                 break;
4093
4094         case OF_RECONFIG_CHANGE_REMOVE:
4095                 /* already depopulated? */
4096                 if (!of_node_check_flag(rd->dn, OF_POPULATED))
4097                         return NOTIFY_OK;
4098
4099                 /* find our device by node */
4100                 spi = of_find_spi_device_by_node(rd->dn);
4101                 if (spi == NULL)
4102                         return NOTIFY_OK;       /* no? not meant for us */
4103
4104                 /* unregister takes one ref away */
4105                 spi_unregister_device(spi);
4106
4107                 /* and put the reference of the find */
4108                 put_device(&spi->dev);
4109                 break;
4110         }
4111
4112         return NOTIFY_OK;
4113 }
4114
4115 static struct notifier_block spi_of_notifier = {
4116         .notifier_call = of_spi_notify,
4117 };
4118 #else /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
4119 extern struct notifier_block spi_of_notifier;
4120 #endif /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
4121
4122 #if IS_ENABLED(CONFIG_ACPI)
4123 static int spi_acpi_controller_match(struct device *dev, const void *data)
4124 {
4125         return ACPI_COMPANION(dev->parent) == data;
4126 }
4127
4128 static struct spi_controller *acpi_spi_find_controller_by_adev(struct acpi_device *adev)
4129 {
4130         struct device *dev;
4131
4132         dev = class_find_device(&spi_master_class, NULL, adev,
4133                                 spi_acpi_controller_match);
4134         if (!dev && IS_ENABLED(CONFIG_SPI_SLAVE))
4135                 dev = class_find_device(&spi_slave_class, NULL, adev,
4136                                         spi_acpi_controller_match);
4137         if (!dev)
4138                 return NULL;
4139
4140         return container_of(dev, struct spi_controller, dev);
4141 }
4142
4143 static struct spi_device *acpi_spi_find_device_by_adev(struct acpi_device *adev)
4144 {
4145         struct device *dev;
4146
4147         dev = bus_find_device_by_acpi_dev(&spi_bus_type, adev);
4148         return to_spi_device(dev);
4149 }
4150
4151 static int acpi_spi_notify(struct notifier_block *nb, unsigned long value,
4152                            void *arg)
4153 {
4154         struct acpi_device *adev = arg;
4155         struct spi_controller *ctlr;
4156         struct spi_device *spi;
4157
4158         switch (value) {
4159         case ACPI_RECONFIG_DEVICE_ADD:
4160                 ctlr = acpi_spi_find_controller_by_adev(adev->parent);
4161                 if (!ctlr)
4162                         break;
4163
4164                 acpi_register_spi_device(ctlr, adev);
4165                 put_device(&ctlr->dev);
4166                 break;
4167         case ACPI_RECONFIG_DEVICE_REMOVE:
4168                 if (!acpi_device_enumerated(adev))
4169                         break;
4170
4171                 spi = acpi_spi_find_device_by_adev(adev);
4172                 if (!spi)
4173                         break;
4174
4175                 spi_unregister_device(spi);
4176                 put_device(&spi->dev);
4177                 break;
4178         }
4179
4180         return NOTIFY_OK;
4181 }
4182
4183 static struct notifier_block spi_acpi_notifier = {
4184         .notifier_call = acpi_spi_notify,
4185 };
4186 #else
4187 extern struct notifier_block spi_acpi_notifier;
4188 #endif
4189
4190 static int __init spi_init(void)
4191 {
4192         int     status;
4193
4194         buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
4195         if (!buf) {
4196                 status = -ENOMEM;
4197                 goto err0;
4198         }
4199
4200         status = bus_register(&spi_bus_type);
4201         if (status < 0)
4202                 goto err1;
4203
4204         status = class_register(&spi_master_class);
4205         if (status < 0)
4206                 goto err2;
4207
4208         if (IS_ENABLED(CONFIG_SPI_SLAVE)) {
4209                 status = class_register(&spi_slave_class);
4210                 if (status < 0)
4211                         goto err3;
4212         }
4213
4214         if (IS_ENABLED(CONFIG_OF_DYNAMIC))
4215                 WARN_ON(of_reconfig_notifier_register(&spi_of_notifier));
4216         if (IS_ENABLED(CONFIG_ACPI))
4217                 WARN_ON(acpi_reconfig_notifier_register(&spi_acpi_notifier));
4218
4219         return 0;
4220
4221 err3:
4222         class_unregister(&spi_master_class);
4223 err2:
4224         bus_unregister(&spi_bus_type);
4225 err1:
4226         kfree(buf);
4227         buf = NULL;
4228 err0:
4229         return status;
4230 }
4231
4232 /* board_info is normally registered in arch_initcall(),
4233  * but even essential drivers wait till later
4234  *
4235  * REVISIT only boardinfo really needs static linking. the rest (device and
4236  * driver registration) _could_ be dynamically linked (modular) ... costs
4237  * include needing to have boardinfo data structures be much more public.
4238  */
4239 postcore_initcall(spi_init);