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 struct bus_type spi_bus_type = {
 378         .name           = "spi",
 379         .dev_groups     = spi_dev_groups,
 380         .match          = spi_match_device,
 381         .uevent         = spi_uevent,
 382 };
 383 EXPORT_SYMBOL_GPL(spi_bus_type);
 384
 385
 386 static int spi_drv_probe(struct device *dev)
 387 {
 388         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
 389         struct spi_device               *spi = to_spi_device(dev);
 390         int ret;
 391
 392         ret = of_clk_set_defaults(dev->of_node, false);
 393         if (ret)
 394                 return ret;
 395
 396         if (dev->of_node) {
 397                 spi->irq = of_irq_get(dev->of_node, 0);
 398                 if (spi->irq == -EPROBE_DEFER)
 399                         return -EPROBE_DEFER;
 400                 if (spi->irq < 0)
 401                         spi->irq = 0;
 402         }
 403
 404         ret = dev_pm_domain_attach(dev, true);
 405         if (ret)
 406                 return ret;
 407
 408         ret = sdrv->probe(spi);
 409         if (ret)
 410                 dev_pm_domain_detach(dev, true);
 411
 412         return ret;
 413 }
 414
 415 static int spi_drv_remove(struct device *dev)
 416 {
 417         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
 418         int ret;
 419
 420         ret = sdrv->remove(to_spi_device(dev));
 421         dev_pm_domain_detach(dev, true);
 422
 423         return ret;
 424 }
 425
 426 static void spi_drv_shutdown(struct device *dev)
 427 {
 428         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
 429
 430         sdrv->shutdown(to_spi_device(dev));
 431 }
 432
 433 /**
 434  * __spi_register_driver - register a SPI driver
 435  * @owner: owner module of the driver to register
 436  * @sdrv: the driver to register
 437  * Context: can sleep
 438  *
 439  * Return: zero on success, else a negative error code.
 440  */
 441 int __spi_register_driver(struct module *owner, struct spi_driver *sdrv)
 442 {
 443         sdrv->driver.owner = owner;
 444         sdrv->driver.bus = &spi_bus_type;
 445         if (sdrv->probe)
 446                 sdrv->driver.probe = spi_drv_probe;
 447         if (sdrv->remove)
 448                 sdrv->driver.remove = spi_drv_remove;
 449         if (sdrv->shutdown)
 450                 sdrv->driver.shutdown = spi_drv_shutdown;
 451         return driver_register(&sdrv->driver);
 452 }
 453 EXPORT_SYMBOL_GPL(__spi_register_driver);
 454
 455 /*-------------------------------------------------------------------------*/
 456
 457 /* SPI devices should normally not be created by SPI device drivers; that
 458  * would make them board-specific.  Similarly with SPI controller drivers.
 459  * Device registration normally goes into like arch/.../mach.../board-YYY.c
 460  * with other readonly (flashable) information about mainboard devices.
 461  */
 462
 463 struct boardinfo {
 464         struct list_head        list;
 465         struct spi_board_info   board_info;
 466 };
 467
 468 static LIST_HEAD(board_list);
 469 static LIST_HEAD(spi_controller_list);
 470
 471 /*
 472  * Used to protect add/del operation for board_info list and
 473  * spi_controller list, and their matching process
 474  * also used to protect object of type struct idr
 475  */
 476 static DEFINE_MUTEX(board_lock);
 477
 478 /*
 479  * Prevents addition of devices with same chip select and
 480  * addition of devices below an unregistering controller.
 481  */
 482 static DEFINE_MUTEX(spi_add_lock);
 483
 484 /**
 485  * spi_alloc_device - Allocate a new SPI device
 486  * @ctlr: Controller to which device is connected
 487  * Context: can sleep
 488  *
 489  * Allows a driver to allocate and initialize a spi_device without
 490  * registering it immediately.  This allows a driver to directly
 491  * fill the spi_device with device parameters before calling
 492  * spi_add_device() on it.
 493  *
 494  * Caller is responsible to call spi_add_device() on the returned
 495  * spi_device structure to add it to the SPI controller.  If the caller
 496  * needs to discard the spi_device without adding it, then it should
 497  * call spi_dev_put() on it.
 498  *
 499  * Return: a pointer to the new device, or NULL.
 500  */
 501 struct spi_device *spi_alloc_device(struct spi_controller *ctlr)
 502 {
 503         struct spi_device       *spi;
 504
 505         if (!spi_controller_get(ctlr))
 506                 return NULL;
 507
 508         spi = kzalloc(sizeof(*spi), GFP_KERNEL);
 509         if (!spi) {
 510                 spi_controller_put(ctlr);
 511                 return NULL;
 512         }
 513
 514         spi->master = spi->controller = ctlr;
 515         spi->dev.parent = &ctlr->dev;
 516         spi->dev.bus = &spi_bus_type;
 517         spi->dev.release = spidev_release;
 518         spi->cs_gpio = -ENOENT;
 519         spi->mode = ctlr->buswidth_override_bits;
 520
 521         spin_lock_init(&spi->statistics.lock);
 522
 523         device_initialize(&spi->dev);
 524         return spi;
 525 }
 526 EXPORT_SYMBOL_GPL(spi_alloc_device);
 527
 528 static void spi_dev_set_name(struct spi_device *spi)
 529 {
 530         struct acpi_device *adev = ACPI_COMPANION(&spi->dev);
 531
 532         if (adev) {
 533                 dev_set_name(&spi->dev, "spi-%s", acpi_dev_name(adev));
 534                 return;
 535         }
 536
 537         dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->controller->dev),
 538                      spi->chip_select);
 539 }
 540
 541 static int spi_dev_check(struct device *dev, void *data)
 542 {
 543         struct spi_device *spi = to_spi_device(dev);
 544         struct spi_device *new_spi = data;
 545
 546         if (spi->controller == new_spi->controller &&
 547             spi->chip_select == new_spi->chip_select)
 548                 return -EBUSY;
 549         return 0;
 550 }
 551
 552 /**
 553  * spi_add_device - Add spi_device allocated with spi_alloc_device
 554  * @spi: spi_device to register
 555  *
 556  * Companion function to spi_alloc_device.  Devices allocated with
 557  * spi_alloc_device can be added onto the spi bus with this function.
 558  *
 559  * Return: 0 on success; negative errno on failure
 560  */
 561 int spi_add_device(struct spi_device *spi)
 562 {
 563         struct spi_controller *ctlr = spi->controller;
 564         struct device *dev = ctlr->dev.parent;
 565         int status;
 566
 567         /* Chipselects are numbered 0..max; validate. */
 568         if (spi->chip_select >= ctlr->num_chipselect) {
 569                 dev_err(dev, "cs%d >= max %d\n", spi->chip_select,
 570                         ctlr->num_chipselect);
 571                 return -EINVAL;
 572         }
 573
 574         /* Set the bus ID string */
 575         spi_dev_set_name(spi);
 576
 577         /* We need to make sure there's no other device with this
 578          * chipselect **BEFORE** we call setup(), else we'll trash
 579          * its configuration.  Lock against concurrent add() calls.
 580          */
 581         mutex_lock(&spi_add_lock);
 582
 583         status = bus_for_each_dev(&spi_bus_type, NULL, spi, spi_dev_check);
 584         if (status) {
 585                 dev_err(dev, "chipselect %d already in use\n",
 586                                 spi->chip_select);
 587                 goto done;
 588         }
 589
 590         /* Controller may unregister concurrently */
 591         if (IS_ENABLED(CONFIG_SPI_DYNAMIC) &&
 592             !device_is_registered(&ctlr->dev)) {
 593                 status = -ENODEV;
 594                 goto done;
 595         }
 596
 597         /* Descriptors take precedence */
 598         if (ctlr->cs_gpiods)
 599                 spi->cs_gpiod = ctlr->cs_gpiods[spi->chip_select];
 600         else if (ctlr->cs_gpios)
 601                 spi->cs_gpio = ctlr->cs_gpios[spi->chip_select];
 602
 603         /* Drivers may modify this initial i/o setup, but will
 604          * normally rely on the device being setup.  Devices
 605          * using SPI_CS_HIGH can't coexist well otherwise...
 606          */
 607         status = spi_setup(spi);
 608         if (status < 0) {
 609                 dev_err(dev, "can't setup %s, status %d\n",
 610                                 dev_name(&spi->dev), status);
 611                 goto done;
 612         }
 613
 614         /* Device may be bound to an active driver when this returns */
 615         status = device_add(&spi->dev);
 616         if (status < 0)
 617                 dev_err(dev, "can't add %s, status %d\n",
 618                                 dev_name(&spi->dev), status);
 619         else
 620                 dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
 621
 622 done:
 623         mutex_unlock(&spi_add_lock);
 624         return status;
 625 }
 626 EXPORT_SYMBOL_GPL(spi_add_device);
 627
 628 /**
 629  * spi_new_device - instantiate one new SPI device
 630  * @ctlr: Controller to which device is connected
 631  * @chip: Describes the SPI device
 632  * Context: can sleep
 633  *
 634  * On typical mainboards, this is purely internal; and it's not needed
 635  * after board init creates the hard-wired devices.  Some development
 636  * platforms may not be able to use spi_register_board_info though, and
 637  * this is exported so that for example a USB or parport based adapter
 638  * driver could add devices (which it would learn about out-of-band).
 639  *
 640  * Return: the new device, or NULL.
 641  */
 642 struct spi_device *spi_new_device(struct spi_controller *ctlr,
 643                                   struct spi_board_info *chip)
 644 {
 645         struct spi_device       *proxy;
 646         int                     status;
 647
 648         /* NOTE:  caller did any chip->bus_num checks necessary.
 649          *
 650          * Also, unless we change the return value convention to use
 651          * error-or-pointer (not NULL-or-pointer), troubleshootability
 652          * suggests syslogged diagnostics are best here (ugh).
 653          */
 654
 655         proxy = spi_alloc_device(ctlr);
 656         if (!proxy)
 657                 return NULL;
 658
 659         WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
 660
 661         proxy->chip_select = chip->chip_select;
 662         proxy->max_speed_hz = chip->max_speed_hz;
 663         proxy->mode = chip->mode;
 664         proxy->irq = chip->irq;
 665         strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
 666         proxy->dev.platform_data = (void *) chip->platform_data;
 667         proxy->controller_data = chip->controller_data;
 668         proxy->controller_state = NULL;
 669
 670         if (chip->properties) {
 671                 status = device_add_properties(&proxy->dev, chip->properties);
 672                 if (status) {
 673                         dev_err(&ctlr->dev,
 674                                 "failed to add properties to '%s': %d\n",
 675                                 chip->modalias, status);
 676                         goto err_dev_put;
 677                 }
 678         }
 679
 680         status = spi_add_device(proxy);
 681         if (status < 0)
 682                 goto err_remove_props;
 683
 684         return proxy;
 685
 686 err_remove_props:
 687         if (chip->properties)
 688                 device_remove_properties(&proxy->dev);
 689 err_dev_put:
 690         spi_dev_put(proxy);
 691         return NULL;
 692 }
 693 EXPORT_SYMBOL_GPL(spi_new_device);
 694
 695 /**
 696  * spi_unregister_device - unregister a single SPI device
 697  * @spi: spi_device to unregister
 698  *
 699  * Start making the passed SPI device vanish. Normally this would be handled
 700  * by spi_unregister_controller().
 701  */
 702 void spi_unregister_device(struct spi_device *spi)
 703 {
 704         if (!spi)
 705                 return;
 706
 707         if (spi->dev.of_node) {
 708                 of_node_clear_flag(spi->dev.of_node, OF_POPULATED);
 709                 of_node_put(spi->dev.of_node);
 710         }
 711         if (ACPI_COMPANION(&spi->dev))
 712                 acpi_device_clear_enumerated(ACPI_COMPANION(&spi->dev));
 713         device_unregister(&spi->dev);
 714 }
 715 EXPORT_SYMBOL_GPL(spi_unregister_device);
 716
 717 static void spi_match_controller_to_boardinfo(struct spi_controller *ctlr,
 718                                               struct spi_board_info *bi)
 719 {
 720         struct spi_device *dev;
 721
 722         if (ctlr->bus_num != bi->bus_num)
 723                 return;
 724
 725         dev = spi_new_device(ctlr, bi);
 726         if (!dev)
 727                 dev_err(ctlr->dev.parent, "can't create new device for %s\n",
 728                         bi->modalias);
 729 }
 730
 731 /**
 732  * spi_register_board_info - register SPI devices for a given board
 733  * @info: array of chip descriptors
 734  * @n: how many descriptors are provided
 735  * Context: can sleep
 736  *
 737  * Board-specific early init code calls this (probably during arch_initcall)
 738  * with segments of the SPI device table.  Any device nodes are created later,
 739  * after the relevant parent SPI controller (bus_num) is defined.  We keep
 740  * this table of devices forever, so that reloading a controller driver will
 741  * not make Linux forget about these hard-wired devices.
 742  *
 743  * Other code can also call this, e.g. a particular add-on board might provide
 744  * SPI devices through its expansion connector, so code initializing that board
 745  * would naturally declare its SPI devices.
 746  *
 747  * The board info passed can safely be __initdata ... but be careful of
 748  * any embedded pointers (platform_data, etc), they're copied as-is.
 749  * Device properties are deep-copied though.
 750  *
 751  * Return: zero on success, else a negative error code.
 752  */
 753 int spi_register_board_info(struct spi_board_info const *info, unsigned n)
 754 {
 755         struct boardinfo *bi;
 756         int i;
 757
 758         if (!n)
 759                 return 0;
 760
 761         bi = kcalloc(n, sizeof(*bi), GFP_KERNEL);
 762         if (!bi)
 763                 return -ENOMEM;
 764
 765         for (i = 0; i < n; i++, bi++, info++) {
 766                 struct spi_controller *ctlr;
 767
 768                 memcpy(&bi->board_info, info, sizeof(*info));
 769                 if (info->properties) {
 770                         bi->board_info.properties =
 771                                         property_entries_dup(info->properties);
 772                         if (IS_ERR(bi->board_info.properties))
 773                                 return PTR_ERR(bi->board_info.properties);
 774                 }
 775
 776                 mutex_lock(&board_lock);
 777                 list_add_tail(&bi->list, &board_list);
 778                 list_for_each_entry(ctlr, &spi_controller_list, list)
 779                         spi_match_controller_to_boardinfo(ctlr,
 780                                                           &bi->board_info);
 781                 mutex_unlock(&board_lock);
 782         }
 783
 784         return 0;
 785 }
 786
 787 /*-------------------------------------------------------------------------*/
 788
 789 static void spi_set_cs(struct spi_device *spi, bool enable)
 790 {
 791         bool enable1 = enable;
 792
 793         /*
 794          * Avoid calling into the driver (or doing delays) if the chip select
 795          * isn't actually changing from the last time this was called.
 796          */
 797         if ((spi->controller->last_cs_enable == enable) &&
 798             (spi->controller->last_cs_mode_high == (spi->mode & SPI_CS_HIGH)))
 799                 return;
 800
 801         spi->controller->last_cs_enable = enable;
 802         spi->controller->last_cs_mode_high = spi->mode & SPI_CS_HIGH;
 803
 804         if (!spi->controller->set_cs_timing) {
 805                 if (enable1)
 806                         spi_delay_exec(&spi->controller->cs_setup, NULL);
 807                 else
 808                         spi_delay_exec(&spi->controller->cs_hold, NULL);
 809         }
 810
 811         if (spi->mode & SPI_CS_HIGH)
 812                 enable = !enable;
 813
 814         if (spi->cs_gpiod || gpio_is_valid(spi->cs_gpio)) {
 815                 /*
 816                  * Honour the SPI_NO_CS flag and invert the enable line, as
 817                  * active low is default for SPI. Execution paths that handle
 818                  * polarity inversion in gpiolib (such as device tree) will
 819                  * enforce active high using the SPI_CS_HIGH resulting in a
 820                  * double inversion through the code above.
 821                  */
 822                 if (!(spi->mode & SPI_NO_CS)) {
 823                         if (spi->cs_gpiod)
 824                                 gpiod_set_value_cansleep(spi->cs_gpiod,
 825                                                          !enable);
 826                         else
 827                                 gpio_set_value_cansleep(spi->cs_gpio, !enable);
 828                 }
 829                 /* Some SPI masters need both GPIO CS & slave_select */
 830                 if ((spi->controller->flags & SPI_MASTER_GPIO_SS) &&
 831                     spi->controller->set_cs)
 832                         spi->controller->set_cs(spi, !enable);
 833         } else if (spi->controller->set_cs) {
 834                 spi->controller->set_cs(spi, !enable);
 835         }
 836
 837         if (!spi->controller->set_cs_timing) {
 838                 if (!enable1)
 839                         spi_delay_exec(&spi->controller->cs_inactive, NULL);
 840         }
 841 }
 842
 843 #ifdef CONFIG_HAS_DMA
 844 int spi_map_buf(struct spi_controller *ctlr, struct device *dev,
 845                 struct sg_table *sgt, void *buf, size_t len,
 846                 enum dma_data_direction dir)
 847 {
 848         const bool vmalloced_buf = is_vmalloc_addr(buf);
 849         unsigned int max_seg_size = dma_get_max_seg_size(dev);
 850 #ifdef CONFIG_HIGHMEM
 851         const bool kmap_buf = ((unsigned long)buf >= PKMAP_BASE &&
 852                                 (unsigned long)buf < (PKMAP_BASE +
 853                                         (LAST_PKMAP * PAGE_SIZE)));
 854 #else
 855         const bool kmap_buf = false;
 856 #endif
 857         int desc_len;
 858         int sgs;
 859         struct page *vm_page;
 860         struct scatterlist *sg;
 861         void *sg_buf;
 862         size_t min;
 863         int i, ret;
 864
 865         if (vmalloced_buf || kmap_buf) {
 866                 desc_len = min_t(int, max_seg_size, PAGE_SIZE);
 867                 sgs = DIV_ROUND_UP(len + offset_in_page(buf), desc_len);
 868         } else if (virt_addr_valid(buf)) {
 869                 desc_len = min_t(int, max_seg_size, ctlr->max_dma_len);
 870                 sgs = DIV_ROUND_UP(len, desc_len);
 871         } else {
 872                 return -EINVAL;
 873         }
 874
 875         ret = sg_alloc_table(sgt, sgs, GFP_KERNEL);
 876         if (ret != 0)
 877                 return ret;
 878
 879         sg = &sgt->sgl[0];
 880         for (i = 0; i < sgs; i++) {
 881
 882                 if (vmalloced_buf || kmap_buf) {
 883                         /*
 884                          * Next scatterlist entry size is the minimum between
 885                          * the desc_len and the remaining buffer length that
 886                          * fits in a page.
 887                          */
 888                         min = min_t(size_t, desc_len,
 889                                     min_t(size_t, len,
 890                                           PAGE_SIZE - offset_in_page(buf)));
 891                         if (vmalloced_buf)
 892                                 vm_page = vmalloc_to_page(buf);
 893                         else
 894                                 vm_page = kmap_to_page(buf);
 895                         if (!vm_page) {
 896                                 sg_free_table(sgt);
 897                                 return -ENOMEM;
 898                         }
 899                         sg_set_page(sg, vm_page,
 900                                     min, offset_in_page(buf));
 901                 } else {
 902                         min = min_t(size_t, len, desc_len);
 903                         sg_buf = buf;
 904                         sg_set_buf(sg, sg_buf, min);
 905                 }
 906
 907                 buf += min;
 908                 len -= min;
 909                 sg = sg_next(sg);
 910         }
 911
 912         ret = dma_map_sg(dev, sgt->sgl, sgt->nents, dir);
 913         if (!ret)
 914                 ret = -ENOMEM;
 915         if (ret < 0) {
 916                 sg_free_table(sgt);
 917                 return ret;
 918         }
 919
 920         sgt->nents = ret;
 921
 922         return 0;
 923 }
 924
 925 void spi_unmap_buf(struct spi_controller *ctlr, struct device *dev,
 926                    struct sg_table *sgt, enum dma_data_direction dir)
 927 {
 928         if (sgt->orig_nents) {
 929                 dma_unmap_sg(dev, sgt->sgl, sgt->orig_nents, dir);
 930                 sg_free_table(sgt);
 931         }
 932 }
 933
 934 static int __spi_map_msg(struct spi_controller *ctlr, struct spi_message *msg)
 935 {
 936         struct device *tx_dev, *rx_dev;
 937         struct spi_transfer *xfer;
 938         int ret;
 939
 940         if (!ctlr->can_dma)
 941                 return 0;
 942
 943         if (ctlr->dma_tx)
 944                 tx_dev = ctlr->dma_tx->device->dev;
 945         else
 946                 tx_dev = ctlr->dev.parent;
 947
 948         if (ctlr->dma_rx)
 949                 rx_dev = ctlr->dma_rx->device->dev;
 950         else
 951                 rx_dev = ctlr->dev.parent;
 952
 953         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 954                 if (!ctlr->can_dma(ctlr, msg->spi, xfer))
 955                         continue;
 956
 957                 if (xfer->tx_buf != NULL) {
 958                         ret = spi_map_buf(ctlr, tx_dev, &xfer->tx_sg,
 959                                           (void *)xfer->tx_buf, xfer->len,
 960                                           DMA_TO_DEVICE);
 961                         if (ret != 0)
 962                                 return ret;
 963                 }
 964
 965                 if (xfer->rx_buf != NULL) {
 966                         ret = spi_map_buf(ctlr, rx_dev, &xfer->rx_sg,
 967                                           xfer->rx_buf, xfer->len,
 968                                           DMA_FROM_DEVICE);
 969                         if (ret != 0) {
 970                                 spi_unmap_buf(ctlr, tx_dev, &xfer->tx_sg,
 971                                               DMA_TO_DEVICE);
 972                                 return ret;
 973                         }
 974                 }
 975         }
 976
 977         ctlr->cur_msg_mapped = true;
 978
 979         return 0;
 980 }
 981
 982 static int __spi_unmap_msg(struct spi_controller *ctlr, struct spi_message *msg)
 983 {
 984         struct spi_transfer *xfer;
 985         struct device *tx_dev, *rx_dev;
 986
 987         if (!ctlr->cur_msg_mapped || !ctlr->can_dma)
 988                 return 0;
 989
 990         if (ctlr->dma_tx)
 991                 tx_dev = ctlr->dma_tx->device->dev;
 992         else
 993                 tx_dev = ctlr->dev.parent;
 994
 995         if (ctlr->dma_rx)
 996                 rx_dev = ctlr->dma_rx->device->dev;
 997         else
 998                 rx_dev = ctlr->dev.parent;
 999
1000         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1001                 if (!ctlr->can_dma(ctlr, msg->spi, xfer))
1002                         continue;
1003
1004                 spi_unmap_buf(ctlr, rx_dev, &xfer->rx_sg, DMA_FROM_DEVICE);
1005                 spi_unmap_buf(ctlr, tx_dev, &xfer->tx_sg, DMA_TO_DEVICE);
1006         }
1007
1008         ctlr->cur_msg_mapped = false;
1009
1010         return 0;
1011 }
1012 #else /* !CONFIG_HAS_DMA */
1013 static inline int __spi_map_msg(struct spi_controller *ctlr,
1014                                 struct spi_message *msg)
1015 {
1016         return 0;
1017 }
1018
1019 static inline int __spi_unmap_msg(struct spi_controller *ctlr,
1020                                   struct spi_message *msg)
1021 {
1022         return 0;
1023 }
1024 #endif /* !CONFIG_HAS_DMA */
1025
1026 static inline int spi_unmap_msg(struct spi_controller *ctlr,
1027                                 struct spi_message *msg)
1028 {
1029         struct spi_transfer *xfer;
1030
1031         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1032                 /*
1033                  * Restore the original value of tx_buf or rx_buf if they are
1034                  * NULL.
1035                  */
1036                 if (xfer->tx_buf == ctlr->dummy_tx)
1037                         xfer->tx_buf = NULL;
1038                 if (xfer->rx_buf == ctlr->dummy_rx)
1039                         xfer->rx_buf = NULL;
1040         }
1041
1042         return __spi_unmap_msg(ctlr, msg);
1043 }
1044
1045 static int spi_map_msg(struct spi_controller *ctlr, struct spi_message *msg)
1046 {
1047         struct spi_transfer *xfer;
1048         void *tmp;
1049         unsigned int max_tx, max_rx;
1050
1051         if ((ctlr->flags & (SPI_CONTROLLER_MUST_RX | SPI_CONTROLLER_MUST_TX))
1052                 && !(msg->spi->mode & SPI_3WIRE)) {
1053                 max_tx = 0;
1054                 max_rx = 0;
1055
1056                 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1057                         if ((ctlr->flags & SPI_CONTROLLER_MUST_TX) &&
1058                             !xfer->tx_buf)
1059                                 max_tx = max(xfer->len, max_tx);
1060                         if ((ctlr->flags & SPI_CONTROLLER_MUST_RX) &&
1061                             !xfer->rx_buf)
1062                                 max_rx = max(xfer->len, max_rx);
1063                 }
1064
1065                 if (max_tx) {
1066                         tmp = krealloc(ctlr->dummy_tx, max_tx,
1067                                        GFP_KERNEL | GFP_DMA);
1068                         if (!tmp)
1069                                 return -ENOMEM;
1070                         ctlr->dummy_tx = tmp;
1071                         memset(tmp, 0, max_tx);
1072                 }
1073
1074                 if (max_rx) {
1075                         tmp = krealloc(ctlr->dummy_rx, max_rx,
1076                                        GFP_KERNEL | GFP_DMA);
1077                         if (!tmp)
1078                                 return -ENOMEM;
1079                         ctlr->dummy_rx = tmp;
1080                 }
1081
1082                 if (max_tx || max_rx) {
1083                         list_for_each_entry(xfer, &msg->transfers,
1084                                             transfer_list) {
1085                                 if (!xfer->len)
1086                                         continue;
1087                                 if (!xfer->tx_buf)
1088                                         xfer->tx_buf = ctlr->dummy_tx;
1089                                 if (!xfer->rx_buf)
1090                                         xfer->rx_buf = ctlr->dummy_rx;
1091                         }
1092                 }
1093         }
1094
1095         return __spi_map_msg(ctlr, msg);
1096 }
1097
1098 static int spi_transfer_wait(struct spi_controller *ctlr,
1099                              struct spi_message *msg,
1100                              struct spi_transfer *xfer)
1101 {
1102         struct spi_statistics *statm = &ctlr->statistics;
1103         struct spi_statistics *stats = &msg->spi->statistics;
1104         unsigned long long ms;
1105
1106         if (spi_controller_is_slave(ctlr)) {
1107                 if (wait_for_completion_interruptible(&ctlr->xfer_completion)) {
1108                         dev_dbg(&msg->spi->dev, "SPI transfer interrupted\n");
1109                         return -EINTR;
1110                 }
1111         } else {
1112                 ms = 8LL * 1000LL * xfer->len;
1113                 do_div(ms, xfer->speed_hz);
1114                 ms += ms + 200; /* some tolerance */
1115
1116                 if (ms > UINT_MAX)
1117                         ms = UINT_MAX;
1118
1119                 ms = wait_for_completion_timeout(&ctlr->xfer_completion,
1120                                                  msecs_to_jiffies(ms));
1121
1122                 if (ms == 0) {
1123                         SPI_STATISTICS_INCREMENT_FIELD(statm, timedout);
1124                         SPI_STATISTICS_INCREMENT_FIELD(stats, timedout);
1125                         dev_err(&msg->spi->dev,
1126                                 "SPI transfer timed out\n");
1127                         return -ETIMEDOUT;
1128                 }
1129         }
1130
1131         return 0;
1132 }
1133
1134 static void _spi_transfer_delay_ns(u32 ns)
1135 {
1136         if (!ns)
1137                 return;
1138         if (ns <= 1000) {
1139                 ndelay(ns);
1140         } else {
1141                 u32 us = DIV_ROUND_UP(ns, 1000);
1142
1143                 if (us <= 10)
1144                         udelay(us);
1145                 else
1146                         usleep_range(us, us + DIV_ROUND_UP(us, 10));
1147         }
1148 }
1149
1150 int spi_delay_to_ns(struct spi_delay *_delay, struct spi_transfer *xfer)
1151 {
1152         u32 delay = _delay->value;
1153         u32 unit = _delay->unit;
1154         u32 hz;
1155
1156         if (!delay)
1157                 return 0;
1158
1159         switch (unit) {
1160         case SPI_DELAY_UNIT_USECS:
1161                 delay *= 1000;
1162                 break;
1163         case SPI_DELAY_UNIT_NSECS: /* nothing to do here */
1164                 break;
1165         case SPI_DELAY_UNIT_SCK:
1166                 /* clock cycles need to be obtained from spi_transfer */
1167                 if (!xfer)
1168                         return -EINVAL;
1169                 /* if there is no effective speed know, then approximate
1170                  * by underestimating with half the requested hz
1171                  */
1172                 hz = xfer->effective_speed_hz ?: xfer->speed_hz / 2;
1173                 if (!hz)
1174                         return -EINVAL;
1175                 delay *= DIV_ROUND_UP(1000000000, hz);
1176                 break;
1177         default:
1178                 return -EINVAL;
1179         }
1180
1181         return delay;
1182 }
1183 EXPORT_SYMBOL_GPL(spi_delay_to_ns);
1184
1185 int spi_delay_exec(struct spi_delay *_delay, struct spi_transfer *xfer)
1186 {
1187         int delay;
1188
1189         might_sleep();
1190
1191         if (!_delay)
1192                 return -EINVAL;
1193
1194         delay = spi_delay_to_ns(_delay, xfer);
1195         if (delay < 0)
1196                 return delay;
1197
1198         _spi_transfer_delay_ns(delay);
1199
1200         return 0;
1201 }
1202 EXPORT_SYMBOL_GPL(spi_delay_exec);
1203
1204 static void _spi_transfer_cs_change_delay(struct spi_message *msg,
1205                                           struct spi_transfer *xfer)
1206 {
1207         u32 delay = xfer->cs_change_delay.value;
1208         u32 unit = xfer->cs_change_delay.unit;
1209         int ret;
1210
1211         /* return early on "fast" mode - for everything but USECS */
1212         if (!delay) {
1213                 if (unit == SPI_DELAY_UNIT_USECS)
1214                         _spi_transfer_delay_ns(10000);
1215                 return;
1216         }
1217
1218         ret = spi_delay_exec(&xfer->cs_change_delay, xfer);
1219         if (ret) {
1220                 dev_err_once(&msg->spi->dev,
1221                              "Use of unsupported delay unit %i, using default of 10us\n",
1222                              unit);
1223                 _spi_transfer_delay_ns(10000);
1224         }
1225 }
1226
1227 /*
1228  * spi_transfer_one_message - Default implementation of transfer_one_message()
1229  *
1230  * This is a standard implementation of transfer_one_message() for
1231  * drivers which implement a transfer_one() operation.  It provides
1232  * standard handling of delays and chip select management.
1233  */
1234 static int spi_transfer_one_message(struct spi_controller *ctlr,
1235                                     struct spi_message *msg)
1236 {
1237         struct spi_transfer *xfer;
1238         bool keep_cs = false;
1239         int ret = 0;
1240         struct spi_statistics *statm = &ctlr->statistics;
1241         struct spi_statistics *stats = &msg->spi->statistics;
1242
1243         spi_set_cs(msg->spi, true);
1244
1245         SPI_STATISTICS_INCREMENT_FIELD(statm, messages);
1246         SPI_STATISTICS_INCREMENT_FIELD(stats, messages);
1247
1248         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1249                 trace_spi_transfer_start(msg, xfer);
1250
1251                 spi_statistics_add_transfer_stats(statm, xfer, ctlr);
1252                 spi_statistics_add_transfer_stats(stats, xfer, ctlr);
1253
1254                 if (!ctlr->ptp_sts_supported) {
1255                         xfer->ptp_sts_word_pre = 0;
1256                         ptp_read_system_prets(xfer->ptp_sts);
1257                 }
1258
1259                 if (xfer->tx_buf || xfer->rx_buf) {
1260                         reinit_completion(&ctlr->xfer_completion);
1261
1262 fallback_pio:
1263                         ret = ctlr->transfer_one(ctlr, msg->spi, xfer);
1264                         if (ret < 0) {
1265                                 if (ctlr->cur_msg_mapped &&
1266                                    (xfer->error & SPI_TRANS_FAIL_NO_START)) {
1267                                         __spi_unmap_msg(ctlr, msg);
1268                                         ctlr->fallback = true;
1269                                         xfer->error &= ~SPI_TRANS_FAIL_NO_START;
1270                                         goto fallback_pio;
1271                                 }
1272
1273                                 SPI_STATISTICS_INCREMENT_FIELD(statm,
1274                                                                errors);
1275                                 SPI_STATISTICS_INCREMENT_FIELD(stats,
1276                                                                errors);
1277                                 dev_err(&msg->spi->dev,
1278                                         "SPI transfer failed: %d\n", ret);
1279                                 goto out;
1280                         }
1281
1282                         if (ret > 0) {
1283                                 ret = spi_transfer_wait(ctlr, msg, xfer);
1284                                 if (ret < 0)
1285                                         msg->status = ret;
1286                         }
1287                 } else {
1288                         if (xfer->len)
1289                                 dev_err(&msg->spi->dev,
1290                                         "Bufferless transfer has length %u\n",
1291                                         xfer->len);
1292                 }
1293
1294                 if (!ctlr->ptp_sts_supported) {
1295                         ptp_read_system_postts(xfer->ptp_sts);
1296                         xfer->ptp_sts_word_post = xfer->len;
1297                 }
1298
1299                 trace_spi_transfer_stop(msg, xfer);
1300
1301                 if (msg->status != -EINPROGRESS)
1302                         goto out;
1303
1304                 spi_transfer_delay_exec(xfer);
1305
1306                 if (xfer->cs_change) {
1307                         if (list_is_last(&xfer->transfer_list,
1308                                          &msg->transfers)) {
1309                                 keep_cs = true;
1310                         } else {
1311                                 spi_set_cs(msg->spi, false);
1312                                 _spi_transfer_cs_change_delay(msg, xfer);
1313                                 spi_set_cs(msg->spi, true);
1314                         }
1315                 }
1316
1317                 msg->actual_length += xfer->len;
1318         }
1319
1320 out:
1321         if (ret != 0 || !keep_cs)
1322                 spi_set_cs(msg->spi, false);
1323
1324         if (msg->status == -EINPROGRESS)
1325                 msg->status = ret;
1326
1327         if (msg->status && ctlr->handle_err)
1328                 ctlr->handle_err(ctlr, msg);
1329
1330         spi_res_release(ctlr, msg);
1331
1332         spi_finalize_current_message(ctlr);
1333
1334         return ret;
1335 }
1336
1337 /**
1338  * spi_finalize_current_transfer - report completion of a transfer
1339  * @ctlr: the controller reporting completion
1340  *
1341  * Called by SPI drivers using the core transfer_one_message()
1342  * implementation to notify it that the current interrupt driven
1343  * transfer has finished and the next one may be scheduled.
1344  */
1345 void spi_finalize_current_transfer(struct spi_controller *ctlr)
1346 {
1347         complete(&ctlr->xfer_completion);
1348 }
1349 EXPORT_SYMBOL_GPL(spi_finalize_current_transfer);
1350
1351 static void spi_idle_runtime_pm(struct spi_controller *ctlr)
1352 {
1353         if (ctlr->auto_runtime_pm) {
1354                 pm_runtime_mark_last_busy(ctlr->dev.parent);
1355                 pm_runtime_put_autosuspend(ctlr->dev.parent);
1356         }
1357 }
1358
1359 /**
1360  * __spi_pump_messages - function which processes spi message queue
1361  * @ctlr: controller to process queue for
1362  * @in_kthread: true if we are in the context of the message pump thread
1363  *
1364  * This function checks if there is any spi message in the queue that
1365  * needs processing and if so call out to the driver to initialize hardware
1366  * and transfer each message.
1367  *
1368  * Note that it is called both from the kthread itself and also from
1369  * inside spi_sync(); the queue extraction handling at the top of the
1370  * function should deal with this safely.
1371  */
1372 static void __spi_pump_messages(struct spi_controller *ctlr, bool in_kthread)
1373 {
1374         struct spi_transfer *xfer;
1375         struct spi_message *msg;
1376         bool was_busy = false;
1377         unsigned long flags;
1378         int ret;
1379
1380         /* Lock queue */
1381         spin_lock_irqsave(&ctlr->queue_lock, flags);
1382
1383         /* Make sure we are not already running a message */
1384         if (ctlr->cur_msg) {
1385                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1386                 return;
1387         }
1388
1389         /* If another context is idling the device then defer */
1390         if (ctlr->idling) {
1391                 kthread_queue_work(ctlr->kworker, &ctlr->pump_messages);
1392                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1393                 return;
1394         }
1395
1396         /* Check if the queue is idle */
1397         if (list_empty(&ctlr->queue) || !ctlr->running) {
1398                 if (!ctlr->busy) {
1399                         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1400                         return;
1401                 }
1402
1403                 /* Defer any non-atomic teardown to the thread */
1404                 if (!in_kthread) {
1405                         if (!ctlr->dummy_rx && !ctlr->dummy_tx &&
1406                             !ctlr->unprepare_transfer_hardware) {
1407                                 spi_idle_runtime_pm(ctlr);
1408                                 ctlr->busy = false;
1409                                 trace_spi_controller_idle(ctlr);
1410                         } else {
1411                                 kthread_queue_work(ctlr->kworker,
1412                                                    &ctlr->pump_messages);
1413                         }
1414                         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1415                         return;
1416                 }
1417
1418                 ctlr->busy = false;
1419                 ctlr->idling = true;
1420                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1421
1422                 kfree(ctlr->dummy_rx);
1423                 ctlr->dummy_rx = NULL;
1424                 kfree(ctlr->dummy_tx);
1425                 ctlr->dummy_tx = NULL;
1426                 if (ctlr->unprepare_transfer_hardware &&
1427                     ctlr->unprepare_transfer_hardware(ctlr))
1428                         dev_err(&ctlr->dev,
1429                                 "failed to unprepare transfer hardware\n");
1430                 spi_idle_runtime_pm(ctlr);
1431                 trace_spi_controller_idle(ctlr);
1432
1433                 spin_lock_irqsave(&ctlr->queue_lock, flags);
1434                 ctlr->idling = false;
1435                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1436                 return;
1437         }
1438
1439         /* Extract head of queue */
1440         msg = list_first_entry(&ctlr->queue, struct spi_message, queue);
1441         ctlr->cur_msg = msg;
1442
1443         list_del_init(&msg->queue);
1444         if (ctlr->busy)
1445                 was_busy = true;
1446         else
1447                 ctlr->busy = true;
1448         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1449
1450         mutex_lock(&ctlr->io_mutex);
1451
1452         if (!was_busy && ctlr->auto_runtime_pm) {
1453                 ret = pm_runtime_get_sync(ctlr->dev.parent);
1454                 if (ret < 0) {
1455                         pm_runtime_put_noidle(ctlr->dev.parent);
1456                         dev_err(&ctlr->dev, "Failed to power device: %d\n",
1457                                 ret);
1458                         mutex_unlock(&ctlr->io_mutex);
1459                         return;
1460                 }
1461         }
1462
1463         if (!was_busy)
1464                 trace_spi_controller_busy(ctlr);
1465
1466         if (!was_busy && ctlr->prepare_transfer_hardware) {
1467                 ret = ctlr->prepare_transfer_hardware(ctlr);
1468                 if (ret) {
1469                         dev_err(&ctlr->dev,
1470                                 "failed to prepare transfer hardware: %d\n",
1471                                 ret);
1472
1473                         if (ctlr->auto_runtime_pm)
1474                                 pm_runtime_put(ctlr->dev.parent);
1475
1476                         msg->status = ret;
1477                         spi_finalize_current_message(ctlr);
1478
1479                         mutex_unlock(&ctlr->io_mutex);
1480                         return;
1481                 }
1482         }
1483
1484         trace_spi_message_start(msg);
1485
1486         if (ctlr->prepare_message) {
1487                 ret = ctlr->prepare_message(ctlr, msg);
1488                 if (ret) {
1489                         dev_err(&ctlr->dev, "failed to prepare message: %d\n",
1490                                 ret);
1491                         msg->status = ret;
1492                         spi_finalize_current_message(ctlr);
1493                         goto out;
1494                 }
1495                 ctlr->cur_msg_prepared = true;
1496         }
1497
1498         ret = spi_map_msg(ctlr, msg);
1499         if (ret) {
1500                 msg->status = ret;
1501                 spi_finalize_current_message(ctlr);
1502                 goto out;
1503         }
1504
1505         if (!ctlr->ptp_sts_supported && !ctlr->transfer_one) {
1506                 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1507                         xfer->ptp_sts_word_pre = 0;
1508                         ptp_read_system_prets(xfer->ptp_sts);
1509                 }
1510         }
1511
1512         ret = ctlr->transfer_one_message(ctlr, msg);
1513         if (ret) {
1514                 dev_err(&ctlr->dev,
1515                         "failed to transfer one message from queue\n");
1516                 goto out;
1517         }
1518
1519 out:
1520         mutex_unlock(&ctlr->io_mutex);
1521
1522         /* Prod the scheduler in case transfer_one() was busy waiting */
1523         if (!ret)
1524                 cond_resched();
1525 }
1526
1527 /**
1528  * spi_pump_messages - kthread work function which processes spi message queue
1529  * @work: pointer to kthread work struct contained in the controller struct
1530  */
1531 static void spi_pump_messages(struct kthread_work *work)
1532 {
1533         struct spi_controller *ctlr =
1534                 container_of(work, struct spi_controller, pump_messages);
1535
1536         __spi_pump_messages(ctlr, true);
1537 }
1538
1539 /**
1540  * spi_take_timestamp_pre - helper for drivers to collect the beginning of the
1541  *                          TX timestamp for the requested byte from the SPI
1542  *                          transfer. The frequency with which this function
1543  *                          must be called (once per word, once for the whole
1544  *                          transfer, once per batch of words etc) is arbitrary
1545  *                          as long as the @tx buffer offset is greater than or
1546  *                          equal to the requested byte at the time of the
1547  *                          call. The timestamp is only taken once, at the
1548  *                          first such call. It is assumed that the driver
1549  *                          advances its @tx buffer pointer monotonically.
1550  * @ctlr: Pointer to the spi_controller structure of the driver
1551  * @xfer: Pointer to the transfer being timestamped
1552  * @progress: How many words (not bytes) have been transferred so far
1553  * @irqs_off: If true, will disable IRQs and preemption for the duration of the
1554  *            transfer, for less jitter in time measurement. Only compatible
1555  *            with PIO drivers. If true, must follow up with
1556  *            spi_take_timestamp_post or otherwise system will crash.
1557  *            WARNING: for fully predictable results, the CPU frequency must
1558  *            also be under control (governor).
1559  */
1560 void spi_take_timestamp_pre(struct spi_controller *ctlr,
1561                             struct spi_transfer *xfer,
1562                             size_t progress, bool irqs_off)
1563 {
1564         if (!xfer->ptp_sts)
1565                 return;
1566
1567         if (xfer->timestamped)
1568                 return;
1569
1570         if (progress > xfer->ptp_sts_word_pre)
1571                 return;
1572
1573         /* Capture the resolution of the timestamp */
1574         xfer->ptp_sts_word_pre = progress;
1575
1576         if (irqs_off) {
1577                 local_irq_save(ctlr->irq_flags);
1578                 preempt_disable();
1579         }
1580
1581         ptp_read_system_prets(xfer->ptp_sts);
1582 }
1583 EXPORT_SYMBOL_GPL(spi_take_timestamp_pre);
1584
1585 /**
1586  * spi_take_timestamp_post - helper for drivers to collect the end of the
1587  *                           TX timestamp for the requested byte from the SPI
1588  *                           transfer. Can be called with an arbitrary
1589  *                           frequency: only the first call where @tx exceeds
1590  *                           or is equal to the requested word will be
1591  *                           timestamped.
1592  * @ctlr: Pointer to the spi_controller structure of the driver
1593  * @xfer: Pointer to the transfer being timestamped
1594  * @progress: How many words (not bytes) have been transferred so far
1595  * @irqs_off: If true, will re-enable IRQs and preemption for the local CPU.
1596  */
1597 void spi_take_timestamp_post(struct spi_controller *ctlr,
1598                              struct spi_transfer *xfer,
1599                              size_t progress, bool irqs_off)
1600 {
1601         if (!xfer->ptp_sts)
1602                 return;
1603
1604         if (xfer->timestamped)
1605                 return;
1606
1607         if (progress < xfer->ptp_sts_word_post)
1608                 return;
1609
1610         ptp_read_system_postts(xfer->ptp_sts);
1611
1612         if (irqs_off) {
1613                 local_irq_restore(ctlr->irq_flags);
1614                 preempt_enable();
1615         }
1616
1617         /* Capture the resolution of the timestamp */
1618         xfer->ptp_sts_word_post = progress;
1619
1620         xfer->timestamped = true;
1621 }
1622 EXPORT_SYMBOL_GPL(spi_take_timestamp_post);
1623
1624 /**
1625  * spi_set_thread_rt - set the controller to pump at realtime priority
1626  * @ctlr: controller to boost priority of
1627  *
1628  * This can be called because the controller requested realtime priority
1629  * (by setting the ->rt value before calling spi_register_controller()) or
1630  * because a device on the bus said that its transfers needed realtime
1631  * priority.
1632  *
1633  * NOTE: at the moment if any device on a bus says it needs realtime then
1634  * the thread will be at realtime priority for all transfers on that
1635  * controller.  If this eventually becomes a problem we may see if we can
1636  * find a way to boost the priority only temporarily during relevant
1637  * transfers.
1638  */
1639 static void spi_set_thread_rt(struct spi_controller *ctlr)
1640 {
1641         dev_info(&ctlr->dev,
1642                 "will run message pump with realtime priority\n");
1643         sched_set_fifo(ctlr->kworker->task);
1644 }
1645
1646 static int spi_init_queue(struct spi_controller *ctlr)
1647 {
1648         ctlr->running = false;
1649         ctlr->busy = false;
1650
1651         ctlr->kworker = kthread_create_worker(0, dev_name(&ctlr->dev));
1652         if (IS_ERR(ctlr->kworker)) {
1653                 dev_err(&ctlr->dev, "failed to create message pump kworker\n");
1654                 return PTR_ERR(ctlr->kworker);
1655         }
1656
1657         kthread_init_work(&ctlr->pump_messages, spi_pump_messages);
1658
1659         /*
1660          * Controller config will indicate if this controller should run the
1661          * message pump with high (realtime) priority to reduce the transfer
1662          * latency on the bus by minimising the delay between a transfer
1663          * request and the scheduling of the message pump thread. Without this
1664          * setting the message pump thread will remain at default priority.
1665          */
1666         if (ctlr->rt)
1667                 spi_set_thread_rt(ctlr);
1668
1669         return 0;
1670 }
1671
1672 /**
1673  * spi_get_next_queued_message() - called by driver to check for queued
1674  * messages
1675  * @ctlr: the controller to check for queued messages
1676  *
1677  * If there are more messages in the queue, the next message is returned from
1678  * this call.
1679  *
1680  * Return: the next message in the queue, else NULL if the queue is empty.
1681  */
1682 struct spi_message *spi_get_next_queued_message(struct spi_controller *ctlr)
1683 {
1684         struct spi_message *next;
1685         unsigned long flags;
1686
1687         /* get a pointer to the next message, if any */
1688         spin_lock_irqsave(&ctlr->queue_lock, flags);
1689         next = list_first_entry_or_null(&ctlr->queue, struct spi_message,
1690                                         queue);
1691         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1692
1693         return next;
1694 }
1695 EXPORT_SYMBOL_GPL(spi_get_next_queued_message);
1696
1697 /**
1698  * spi_finalize_current_message() - the current message is complete
1699  * @ctlr: the controller to return the message to
1700  *
1701  * Called by the driver to notify the core that the message in the front of the
1702  * queue is complete and can be removed from the queue.
1703  */
1704 void spi_finalize_current_message(struct spi_controller *ctlr)
1705 {
1706         struct spi_transfer *xfer;
1707         struct spi_message *mesg;
1708         unsigned long flags;
1709         int ret;
1710
1711         spin_lock_irqsave(&ctlr->queue_lock, flags);
1712         mesg = ctlr->cur_msg;
1713         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1714
1715         if (!ctlr->ptp_sts_supported && !ctlr->transfer_one) {
1716                 list_for_each_entry(xfer, &mesg->transfers, transfer_list) {
1717                         ptp_read_system_postts(xfer->ptp_sts);
1718                         xfer->ptp_sts_word_post = xfer->len;
1719                 }
1720         }
1721
1722         if (unlikely(ctlr->ptp_sts_supported))
1723                 list_for_each_entry(xfer, &mesg->transfers, transfer_list)
1724                         WARN_ON_ONCE(xfer->ptp_sts && !xfer->timestamped);
1725
1726         spi_unmap_msg(ctlr, mesg);
1727
1728         if (ctlr->cur_msg_prepared && ctlr->unprepare_message) {
1729                 ret = ctlr->unprepare_message(ctlr, mesg);
1730                 if (ret) {
1731                         dev_err(&ctlr->dev, "failed to unprepare message: %d\n",
1732                                 ret);
1733                 }
1734         }
1735
1736         spin_lock_irqsave(&ctlr->queue_lock, flags);
1737         ctlr->cur_msg = NULL;
1738         ctlr->cur_msg_prepared = false;
1739         ctlr->fallback = false;
1740         kthread_queue_work(ctlr->kworker, &ctlr->pump_messages);
1741         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1742
1743         trace_spi_message_done(mesg);
1744
1745         mesg->state = NULL;
1746         if (mesg->complete)
1747                 mesg->complete(mesg->context);
1748 }
1749 EXPORT_SYMBOL_GPL(spi_finalize_current_message);
1750
1751 static int spi_start_queue(struct spi_controller *ctlr)
1752 {
1753         unsigned long flags;
1754
1755         spin_lock_irqsave(&ctlr->queue_lock, flags);
1756
1757         if (ctlr->running || ctlr->busy) {
1758                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1759                 return -EBUSY;
1760         }
1761
1762         ctlr->running = true;
1763         ctlr->cur_msg = NULL;
1764         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1765
1766         kthread_queue_work(ctlr->kworker, &ctlr->pump_messages);
1767
1768         return 0;
1769 }
1770
1771 static int spi_stop_queue(struct spi_controller *ctlr)
1772 {
1773         unsigned long flags;
1774         unsigned limit = 500;
1775         int ret = 0;
1776
1777         spin_lock_irqsave(&ctlr->queue_lock, flags);
1778
1779         /*
1780          * This is a bit lame, but is optimized for the common execution path.
1781          * A wait_queue on the ctlr->busy could be used, but then the common
1782          * execution path (pump_messages) would be required to call wake_up or
1783          * friends on every SPI message. Do this instead.
1784          */
1785         while ((!list_empty(&ctlr->queue) || ctlr->busy) && limit--) {
1786                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1787                 usleep_range(10000, 11000);
1788                 spin_lock_irqsave(&ctlr->queue_lock, flags);
1789         }
1790
1791         if (!list_empty(&ctlr->queue) || ctlr->busy)
1792                 ret = -EBUSY;
1793         else
1794                 ctlr->running = false;
1795
1796         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1797
1798         if (ret) {
1799                 dev_warn(&ctlr->dev, "could not stop message queue\n");
1800                 return ret;
1801         }
1802         return ret;
1803 }
1804
1805 static int spi_destroy_queue(struct spi_controller *ctlr)
1806 {
1807         int ret;
1808
1809         ret = spi_stop_queue(ctlr);
1810
1811         /*
1812          * kthread_flush_worker will block until all work is done.
1813          * If the reason that stop_queue timed out is that the work will never
1814          * finish, then it does no good to call flush/stop thread, so
1815          * return anyway.
1816          */
1817         if (ret) {
1818                 dev_err(&ctlr->dev, "problem destroying queue\n");
1819                 return ret;
1820         }
1821
1822         kthread_destroy_worker(ctlr->kworker);
1823
1824         return 0;
1825 }
1826
1827 static int __spi_queued_transfer(struct spi_device *spi,
1828                                  struct spi_message *msg,
1829                                  bool need_pump)
1830 {
1831         struct spi_controller *ctlr = spi->controller;
1832         unsigned long flags;
1833
1834         spin_lock_irqsave(&ctlr->queue_lock, flags);
1835
1836         if (!ctlr->running) {
1837                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1838                 return -ESHUTDOWN;
1839         }
1840         msg->actual_length = 0;
1841         msg->status = -EINPROGRESS;
1842
1843         list_add_tail(&msg->queue, &ctlr->queue);
1844         if (!ctlr->busy && need_pump)
1845                 kthread_queue_work(ctlr->kworker, &ctlr->pump_messages);
1846
1847         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1848         return 0;
1849 }
1850
1851 /**
1852  * spi_queued_transfer - transfer function for queued transfers
1853  * @spi: spi device which is requesting transfer
1854  * @msg: spi message which is to handled is queued to driver queue
1855  *
1856  * Return: zero on success, else a negative error code.
1857  */
1858 static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
1859 {
1860         return __spi_queued_transfer(spi, msg, true);
1861 }
1862
1863 static int spi_controller_initialize_queue(struct spi_controller *ctlr)
1864 {
1865         int ret;
1866
1867         ctlr->transfer = spi_queued_transfer;
1868         if (!ctlr->transfer_one_message)
1869                 ctlr->transfer_one_message = spi_transfer_one_message;
1870
1871         /* Initialize and start queue */
1872         ret = spi_init_queue(ctlr);
1873         if (ret) {
1874                 dev_err(&ctlr->dev, "problem initializing queue\n");
1875                 goto err_init_queue;
1876         }
1877         ctlr->queued = true;
1878         ret = spi_start_queue(ctlr);
1879         if (ret) {
1880                 dev_err(&ctlr->dev, "problem starting queue\n");
1881                 goto err_start_queue;
1882         }
1883
1884         return 0;
1885
1886 err_start_queue:
1887         spi_destroy_queue(ctlr);
1888 err_init_queue:
1889         return ret;
1890 }
1891
1892 /**
1893  * spi_flush_queue - Send all pending messages in the queue from the callers'
1894  *                   context
1895  * @ctlr: controller to process queue for
1896  *
1897  * This should be used when one wants to ensure all pending messages have been
1898  * sent before doing something. Is used by the spi-mem code to make sure SPI
1899  * memory operations do not preempt regular SPI transfers that have been queued
1900  * before the spi-mem operation.
1901  */
1902 void spi_flush_queue(struct spi_controller *ctlr)
1903 {
1904         if (ctlr->transfer == spi_queued_transfer)
1905                 __spi_pump_messages(ctlr, false);
1906 }
1907
1908 /*-------------------------------------------------------------------------*/
1909
1910 #if defined(CONFIG_OF)
1911 static int of_spi_parse_dt(struct spi_controller *ctlr, struct spi_device *spi,
1912                            struct device_node *nc)
1913 {
1914         u32 value;
1915         int rc;
1916
1917         /* Mode (clock phase/polarity/etc.) */
1918         if (of_property_read_bool(nc, "spi-cpha"))
1919                 spi->mode |= SPI_CPHA;
1920         if (of_property_read_bool(nc, "spi-cpol"))
1921                 spi->mode |= SPI_CPOL;
1922         if (of_property_read_bool(nc, "spi-3wire"))
1923                 spi->mode |= SPI_3WIRE;
1924         if (of_property_read_bool(nc, "spi-lsb-first"))
1925                 spi->mode |= SPI_LSB_FIRST;
1926         if (of_property_read_bool(nc, "spi-cs-high"))
1927                 spi->mode |= SPI_CS_HIGH;
1928
1929         /* Device DUAL/QUAD mode */
1930         if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) {
1931                 switch (value) {
1932                 case 1:
1933                         break;
1934                 case 2:
1935                         spi->mode |= SPI_TX_DUAL;
1936                         break;
1937                 case 4:
1938                         spi->mode |= SPI_TX_QUAD;
1939                         break;
1940                 case 8:
1941                         spi->mode |= SPI_TX_OCTAL;
1942                         break;
1943                 default:
1944                         dev_warn(&ctlr->dev,
1945                                 "spi-tx-bus-width %d not supported\n",
1946                                 value);
1947                         break;
1948                 }
1949         }
1950
1951         if (!of_property_read_u32(nc, "spi-rx-bus-width", &value)) {
1952                 switch (value) {
1953                 case 1:
1954                         break;
1955                 case 2:
1956                         spi->mode |= SPI_RX_DUAL;
1957                         break;
1958                 case 4:
1959                         spi->mode |= SPI_RX_QUAD;
1960                         break;
1961                 case 8:
1962                         spi->mode |= SPI_RX_OCTAL;
1963                         break;
1964                 default:
1965                         dev_warn(&ctlr->dev,
1966                                 "spi-rx-bus-width %d not supported\n",
1967                                 value);
1968                         break;
1969                 }
1970         }
1971
1972         if (spi_controller_is_slave(ctlr)) {
1973                 if (!of_node_name_eq(nc, "slave")) {
1974                         dev_err(&ctlr->dev, "%pOF is not called 'slave'\n",
1975                                 nc);
1976                         return -EINVAL;
1977                 }
1978                 return 0;
1979         }
1980
1981         /* Device address */
1982         rc = of_property_read_u32(nc, "reg", &value);
1983         if (rc) {
1984                 dev_err(&ctlr->dev, "%pOF has no valid 'reg' property (%d)\n",
1985                         nc, rc);
1986                 return rc;
1987         }
1988         spi->chip_select = value;
1989
1990         /*
1991          * For descriptors associated with the device, polarity inversion is
1992          * handled in the gpiolib, so all gpio chip selects are "active high"
1993          * in the logical sense, the gpiolib will invert the line if need be.
1994          */
1995         if ((ctlr->use_gpio_descriptors) && ctlr->cs_gpiods &&
1996             ctlr->cs_gpiods[spi->chip_select])
1997                 spi->mode |= SPI_CS_HIGH;
1998
1999         /* Device speed */
2000         if (!of_property_read_u32(nc, "spi-max-frequency", &value))
2001                 spi->max_speed_hz = value;
2002
2003         return 0;
2004 }
2005
2006 static struct spi_device *
2007 of_register_spi_device(struct spi_controller *ctlr, struct device_node *nc)
2008 {
2009         struct spi_device *spi;
2010         int rc;
2011
2012         /* Alloc an spi_device */
2013         spi = spi_alloc_device(ctlr);
2014         if (!spi) {
2015                 dev_err(&ctlr->dev, "spi_device alloc error for %pOF\n", nc);
2016                 rc = -ENOMEM;
2017                 goto err_out;
2018         }
2019
2020         /* Select device driver */
2021         rc = of_modalias_node(nc, spi->modalias,
2022                                 sizeof(spi->modalias));
2023         if (rc < 0) {
2024                 dev_err(&ctlr->dev, "cannot find modalias for %pOF\n", nc);
2025                 goto err_out;
2026         }
2027
2028         rc = of_spi_parse_dt(ctlr, spi, nc);
2029         if (rc)
2030                 goto err_out;
2031
2032         /* Store a pointer to the node in the device structure */
2033         of_node_get(nc);
2034         spi->dev.of_node = nc;
2035
2036         /* Register the new device */
2037         rc = spi_add_device(spi);
2038         if (rc) {
2039                 dev_err(&ctlr->dev, "spi_device register error %pOF\n", nc);
2040                 goto err_of_node_put;
2041         }
2042
2043         return spi;
2044
2045 err_of_node_put:
2046         of_node_put(nc);
2047 err_out:
2048         spi_dev_put(spi);
2049         return ERR_PTR(rc);
2050 }
2051
2052 /**
2053  * of_register_spi_devices() - Register child devices onto the SPI bus
2054  * @ctlr:       Pointer to spi_controller device
2055  *
2056  * Registers an spi_device for each child node of controller node which
2057  * represents a valid SPI slave.
2058  */
2059 static void of_register_spi_devices(struct spi_controller *ctlr)
2060 {
2061         struct spi_device *spi;
2062         struct device_node *nc;
2063
2064         if (!ctlr->dev.of_node)
2065                 return;
2066
2067         for_each_available_child_of_node(ctlr->dev.of_node, nc) {
2068                 if (of_node_test_and_set_flag(nc, OF_POPULATED))
2069                         continue;
2070                 spi = of_register_spi_device(ctlr, nc);
2071                 if (IS_ERR(spi)) {
2072                         dev_warn(&ctlr->dev,
2073                                  "Failed to create SPI device for %pOF\n", nc);
2074                         of_node_clear_flag(nc, OF_POPULATED);
2075                 }
2076         }
2077 }
2078 #else
2079 static void of_register_spi_devices(struct spi_controller *ctlr) { }
2080 #endif
2081
2082 #ifdef CONFIG_ACPI
2083 struct acpi_spi_lookup {
2084         struct spi_controller   *ctlr;
2085         u32                     max_speed_hz;
2086         u32                     mode;
2087         int                     irq;
2088         u8                      bits_per_word;
2089         u8                      chip_select;
2090 };
2091
2092 static void acpi_spi_parse_apple_properties(struct acpi_device *dev,
2093                                             struct acpi_spi_lookup *lookup)
2094 {
2095         const union acpi_object *obj;
2096
2097         if (!x86_apple_machine)
2098                 return;
2099
2100         if (!acpi_dev_get_property(dev, "spiSclkPeriod", ACPI_TYPE_BUFFER, &obj)
2101             && obj->buffer.length >= 4)
2102                 lookup->max_speed_hz  = NSEC_PER_SEC / *(u32 *)obj->buffer.pointer;
2103
2104         if (!acpi_dev_get_property(dev, "spiWordSize", ACPI_TYPE_BUFFER, &obj)
2105             && obj->buffer.length == 8)
2106                 lookup->bits_per_word = *(u64 *)obj->buffer.pointer;
2107
2108         if (!acpi_dev_get_property(dev, "spiBitOrder", ACPI_TYPE_BUFFER, &obj)
2109             && obj->buffer.length == 8 && !*(u64 *)obj->buffer.pointer)
2110                 lookup->mode |= SPI_LSB_FIRST;
2111
2112         if (!acpi_dev_get_property(dev, "spiSPO", ACPI_TYPE_BUFFER, &obj)
2113             && obj->buffer.length == 8 &&  *(u64 *)obj->buffer.pointer)
2114                 lookup->mode |= SPI_CPOL;
2115
2116         if (!acpi_dev_get_property(dev, "spiSPH", ACPI_TYPE_BUFFER, &obj)
2117             && obj->buffer.length == 8 &&  *(u64 *)obj->buffer.pointer)
2118                 lookup->mode |= SPI_CPHA;
2119 }
2120
2121 static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
2122 {
2123         struct acpi_spi_lookup *lookup = data;
2124         struct spi_controller *ctlr = lookup->ctlr;
2125
2126         if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
2127                 struct acpi_resource_spi_serialbus *sb;
2128                 acpi_handle parent_handle;
2129                 acpi_status status;
2130
2131                 sb = &ares->data.spi_serial_bus;
2132                 if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) {
2133
2134                         status = acpi_get_handle(NULL,
2135                                                  sb->resource_source.string_ptr,
2136                                                  &parent_handle);
2137
2138                         if (ACPI_FAILURE(status) ||
2139                             ACPI_HANDLE(ctlr->dev.parent) != parent_handle)
2140                                 return -ENODEV;
2141
2142                         /*
2143                          * ACPI DeviceSelection numbering is handled by the
2144                          * host controller driver in Windows and can vary
2145                          * from driver to driver. In Linux we always expect
2146                          * 0 .. max - 1 so we need to ask the driver to
2147                          * translate between the two schemes.
2148                          */
2149                         if (ctlr->fw_translate_cs) {
2150                                 int cs = ctlr->fw_translate_cs(ctlr,
2151                                                 sb->device_selection);
2152                                 if (cs < 0)
2153                                         return cs;
2154                                 lookup->chip_select = cs;
2155                         } else {
2156                                 lookup->chip_select = sb->device_selection;
2157                         }
2158
2159                         lookup->max_speed_hz = sb->connection_speed;
2160                         lookup->bits_per_word = sb->data_bit_length;
2161
2162                         if (sb->clock_phase == ACPI_SPI_SECOND_PHASE)
2163                                 lookup->mode |= SPI_CPHA;
2164                         if (sb->clock_polarity == ACPI_SPI_START_HIGH)
2165                                 lookup->mode |= SPI_CPOL;
2166                         if (sb->device_polarity == ACPI_SPI_ACTIVE_HIGH)
2167                                 lookup->mode |= SPI_CS_HIGH;
2168                 }
2169         } else if (lookup->irq < 0) {
2170                 struct resource r;
2171
2172                 if (acpi_dev_resource_interrupt(ares, 0, &r))
2173                         lookup->irq = r.start;
2174         }
2175
2176         /* Always tell the ACPI core to skip this resource */
2177         return 1;
2178 }
2179
2180 static acpi_status acpi_register_spi_device(struct spi_controller *ctlr,
2181                                             struct acpi_device *adev)
2182 {
2183         acpi_handle parent_handle = NULL;
2184         struct list_head resource_list;
2185         struct acpi_spi_lookup lookup = {};
2186         struct spi_device *spi;
2187         int ret;
2188
2189         if (acpi_bus_get_status(adev) || !adev->status.present ||
2190             acpi_device_enumerated(adev))
2191                 return AE_OK;
2192
2193         lookup.ctlr             = ctlr;
2194         lookup.irq              = -1;
2195
2196         INIT_LIST_HEAD(&resource_list);
2197         ret = acpi_dev_get_resources(adev, &resource_list,
2198                                      acpi_spi_add_resource, &lookup);
2199         acpi_dev_free_resource_list(&resource_list);
2200
2201         if (ret < 0)
2202                 /* found SPI in _CRS but it points to another controller */
2203                 return AE_OK;
2204
2205         if (!lookup.max_speed_hz &&
2206             !ACPI_FAILURE(acpi_get_parent(adev->handle, &parent_handle)) &&
2207             ACPI_HANDLE(ctlr->dev.parent) == parent_handle) {
2208                 /* Apple does not use _CRS but nested devices for SPI slaves */
2209                 acpi_spi_parse_apple_properties(adev, &lookup);
2210         }
2211
2212         if (!lookup.max_speed_hz)
2213                 return AE_OK;
2214
2215         spi = spi_alloc_device(ctlr);
2216         if (!spi) {
2217                 dev_err(&ctlr->dev, "failed to allocate SPI device for %s\n",
2218                         dev_name(&adev->dev));
2219                 return AE_NO_MEMORY;
2220         }
2221
2222
2223         ACPI_COMPANION_SET(&spi->dev, adev);
2224         spi->max_speed_hz       = lookup.max_speed_hz;
2225         spi->mode               |= lookup.mode;
2226         spi->irq                = lookup.irq;
2227         spi->bits_per_word      = lookup.bits_per_word;
2228         spi->chip_select        = lookup.chip_select;
2229
2230         acpi_set_modalias(adev, acpi_device_hid(adev), spi->modalias,
2231                           sizeof(spi->modalias));
2232
2233         if (spi->irq < 0)
2234                 spi->irq = acpi_dev_gpio_irq_get(adev, 0);
2235
2236         acpi_device_set_enumerated(adev);
2237
2238         adev->power.flags.ignore_parent = true;
2239         if (spi_add_device(spi)) {
2240                 adev->power.flags.ignore_parent = false;
2241                 dev_err(&ctlr->dev, "failed to add SPI device %s from ACPI\n",
2242                         dev_name(&adev->dev));
2243                 spi_dev_put(spi);
2244         }
2245
2246         return AE_OK;
2247 }
2248
2249 static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level,
2250                                        void *data, void **return_value)
2251 {
2252         struct spi_controller *ctlr = data;
2253         struct acpi_device *adev;
2254
2255         if (acpi_bus_get_device(handle, &adev))
2256                 return AE_OK;
2257
2258         return acpi_register_spi_device(ctlr, adev);
2259 }
2260
2261 #define SPI_ACPI_ENUMERATE_MAX_DEPTH            32
2262
2263 static void acpi_register_spi_devices(struct spi_controller *ctlr)
2264 {
2265         acpi_status status;
2266         acpi_handle handle;
2267
2268         handle = ACPI_HANDLE(ctlr->dev.parent);
2269         if (!handle)
2270                 return;
2271
2272         status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
2273                                      SPI_ACPI_ENUMERATE_MAX_DEPTH,
2274                                      acpi_spi_add_device, NULL, ctlr, NULL);
2275         if (ACPI_FAILURE(status))
2276                 dev_warn(&ctlr->dev, "failed to enumerate SPI slaves\n");
2277 }
2278 #else
2279 static inline void acpi_register_spi_devices(struct spi_controller *ctlr) {}
2280 #endif /* CONFIG_ACPI */
2281
2282 static void spi_controller_release(struct device *dev)
2283 {
2284         struct spi_controller *ctlr;
2285
2286         ctlr = container_of(dev, struct spi_controller, dev);
2287         kfree(ctlr);
2288 }
2289
2290 static struct class spi_master_class = {
2291         .name           = "spi_master",
2292         .owner          = THIS_MODULE,
2293         .dev_release    = spi_controller_release,
2294         .dev_groups     = spi_master_groups,
2295 };
2296
2297 #ifdef CONFIG_SPI_SLAVE
2298 /**
2299  * spi_slave_abort - abort the ongoing transfer request on an SPI slave
2300  *                   controller
2301  * @spi: device used for the current transfer
2302  */
2303 int spi_slave_abort(struct spi_device *spi)
2304 {
2305         struct spi_controller *ctlr = spi->controller;
2306
2307         if (spi_controller_is_slave(ctlr) && ctlr->slave_abort)
2308                 return ctlr->slave_abort(ctlr);
2309
2310         return -ENOTSUPP;
2311 }
2312 EXPORT_SYMBOL_GPL(spi_slave_abort);
2313
2314 static int match_true(struct device *dev, void *data)
2315 {
2316         return 1;
2317 }
2318
2319 static ssize_t slave_show(struct device *dev, struct device_attribute *attr,
2320                           char *buf)
2321 {
2322         struct spi_controller *ctlr = container_of(dev, struct spi_controller,
2323                                                    dev);
2324         struct device *child;
2325
2326         child = device_find_child(&ctlr->dev, NULL, match_true);
2327         return sprintf(buf, "%s\n",
2328                        child ? to_spi_device(child)->modalias : NULL);
2329 }
2330
2331 static ssize_t slave_store(struct device *dev, struct device_attribute *attr,
2332                            const char *buf, size_t count)
2333 {
2334         struct spi_controller *ctlr = container_of(dev, struct spi_controller,
2335                                                    dev);
2336         struct spi_device *spi;
2337         struct device *child;
2338         char name[32];
2339         int rc;
2340
2341         rc = sscanf(buf, "%31s", name);
2342         if (rc != 1 || !name[0])
2343                 return -EINVAL;
2344
2345         child = device_find_child(&ctlr->dev, NULL, match_true);
2346         if (child) {
2347                 /* Remove registered slave */
2348                 device_unregister(child);
2349                 put_device(child);
2350         }
2351
2352         if (strcmp(name, "(null)")) {
2353                 /* Register new slave */
2354                 spi = spi_alloc_device(ctlr);
2355                 if (!spi)
2356                         return -ENOMEM;
2357
2358                 strlcpy(spi->modalias, name, sizeof(spi->modalias));
2359
2360                 rc = spi_add_device(spi);
2361                 if (rc) {
2362                         spi_dev_put(spi);
2363                         return rc;
2364                 }
2365         }
2366
2367         return count;
2368 }
2369
2370 static DEVICE_ATTR_RW(slave);
2371
2372 static struct attribute *spi_slave_attrs[] = {
2373         &dev_attr_slave.attr,
2374         NULL,
2375 };
2376
2377 static const struct attribute_group spi_slave_group = {
2378         .attrs = spi_slave_attrs,
2379 };
2380
2381 static const struct attribute_group *spi_slave_groups[] = {
2382         &spi_controller_statistics_group,
2383         &spi_slave_group,
2384         NULL,
2385 };
2386
2387 static struct class spi_slave_class = {
2388         .name           = "spi_slave",
2389         .owner          = THIS_MODULE,
2390         .dev_release    = spi_controller_release,
2391         .dev_groups     = spi_slave_groups,
2392 };
2393 #else
2394 extern struct class spi_slave_class;    /* dummy */
2395 #endif
2396
2397 /**
2398  * __spi_alloc_controller - allocate an SPI master or slave controller
2399  * @dev: the controller, possibly using the platform_bus
2400  * @size: how much zeroed driver-private data to allocate; the pointer to this
2401  *      memory is in the driver_data field of the returned device, accessible
2402  *      with spi_controller_get_devdata(); the memory is cacheline aligned;
2403  *      drivers granting DMA access to portions of their private data need to
2404  *      round up @size using ALIGN(size, dma_get_cache_alignment()).
2405  * @slave: flag indicating whether to allocate an SPI master (false) or SPI
2406  *      slave (true) controller
2407  * Context: can sleep
2408  *
2409  * This call is used only by SPI controller drivers, which are the
2410  * only ones directly touching chip registers.  It's how they allocate
2411  * an spi_controller structure, prior to calling spi_register_controller().
2412  *
2413  * This must be called from context that can sleep.
2414  *
2415  * The caller is responsible for assigning the bus number and initializing the
2416  * controller's methods before calling spi_register_controller(); and (after
2417  * errors adding the device) calling spi_controller_put() to prevent a memory
2418  * leak.
2419  *
2420  * Return: the SPI controller structure on success, else NULL.
2421  */
2422 struct spi_controller *__spi_alloc_controller(struct device *dev,
2423                                               unsigned int size, bool slave)
2424 {
2425         struct spi_controller   *ctlr;
2426         size_t ctlr_size = ALIGN(sizeof(*ctlr), dma_get_cache_alignment());
2427
2428         if (!dev)
2429                 return NULL;
2430
2431         ctlr = kzalloc(size + ctlr_size, GFP_KERNEL);
2432         if (!ctlr)
2433                 return NULL;
2434
2435         device_initialize(&ctlr->dev);
2436         ctlr->bus_num = -1;
2437         ctlr->num_chipselect = 1;
2438         ctlr->slave = slave;
2439         if (IS_ENABLED(CONFIG_SPI_SLAVE) && slave)
2440                 ctlr->dev.class = &spi_slave_class;
2441         else
2442                 ctlr->dev.class = &spi_master_class;
2443         ctlr->dev.parent = dev;
2444         pm_suspend_ignore_children(&ctlr->dev, true);
2445         spi_controller_set_devdata(ctlr, (void *)ctlr + ctlr_size);
2446
2447         return ctlr;
2448 }
2449 EXPORT_SYMBOL_GPL(__spi_alloc_controller);
2450
2451 #ifdef CONFIG_OF
2452 static int of_spi_get_gpio_numbers(struct spi_controller *ctlr)
2453 {
2454         int nb, i, *cs;
2455         struct device_node *np = ctlr->dev.of_node;
2456
2457         if (!np)
2458                 return 0;
2459
2460         nb = of_gpio_named_count(np, "cs-gpios");
2461         ctlr->num_chipselect = max_t(int, nb, ctlr->num_chipselect);
2462
2463         /* Return error only for an incorrectly formed cs-gpios property */
2464         if (nb == 0 || nb == -ENOENT)
2465                 return 0;
2466         else if (nb < 0)
2467                 return nb;
2468
2469         cs = devm_kcalloc(&ctlr->dev, ctlr->num_chipselect, sizeof(int),
2470                           GFP_KERNEL);
2471         ctlr->cs_gpios = cs;
2472
2473         if (!ctlr->cs_gpios)
2474                 return -ENOMEM;
2475
2476         for (i = 0; i < ctlr->num_chipselect; i++)
2477                 cs[i] = -ENOENT;
2478
2479         for (i = 0; i < nb; i++)
2480                 cs[i] = of_get_named_gpio(np, "cs-gpios", i);
2481
2482         return 0;
2483 }
2484 #else
2485 static int of_spi_get_gpio_numbers(struct spi_controller *ctlr)
2486 {
2487         return 0;
2488 }
2489 #endif
2490
2491 /**
2492  * spi_get_gpio_descs() - grab chip select GPIOs for the master
2493  * @ctlr: The SPI master to grab GPIO descriptors for
2494  */
2495 static int spi_get_gpio_descs(struct spi_controller *ctlr)
2496 {
2497         int nb, i;
2498         struct gpio_desc **cs;
2499         struct device *dev = &ctlr->dev;
2500         unsigned long native_cs_mask = 0;
2501         unsigned int num_cs_gpios = 0;
2502
2503         nb = gpiod_count(dev, "cs");
2504         ctlr->num_chipselect = max_t(int, nb, ctlr->num_chipselect);
2505
2506         /* No GPIOs at all is fine, else return the error */
2507         if (nb == 0 || nb == -ENOENT)
2508                 return 0;
2509         else if (nb < 0)
2510                 return nb;
2511
2512         cs = devm_kcalloc(dev, ctlr->num_chipselect, sizeof(*cs),
2513                           GFP_KERNEL);
2514         if (!cs)
2515                 return -ENOMEM;
2516         ctlr->cs_gpiods = cs;
2517
2518         for (i = 0; i < nb; i++) {
2519                 /*
2520                  * Most chipselects are active low, the inverted
2521                  * semantics are handled by special quirks in gpiolib,
2522                  * so initializing them GPIOD_OUT_LOW here means
2523                  * "unasserted", in most cases this will drive the physical
2524                  * line high.
2525                  */
2526                 cs[i] = devm_gpiod_get_index_optional(dev, "cs", i,
2527                                                       GPIOD_OUT_LOW);
2528                 if (IS_ERR(cs[i]))
2529                         return PTR_ERR(cs[i]);
2530
2531                 if (cs[i]) {
2532                         /*
2533                          * If we find a CS GPIO, name it after the device and
2534                          * chip select line.
2535                          */
2536                         char *gpioname;
2537
2538                         gpioname = devm_kasprintf(dev, GFP_KERNEL, "%s CS%d",
2539                                                   dev_name(dev), i);
2540                         if (!gpioname)
2541                                 return -ENOMEM;
2542                         gpiod_set_consumer_name(cs[i], gpioname);
2543                         num_cs_gpios++;
2544                         continue;
2545                 }
2546
2547                 if (ctlr->max_native_cs && i >= ctlr->max_native_cs) {
2548                         dev_err(dev, "Invalid native chip select %d\n", i);
2549                         return -EINVAL;
2550                 }
2551                 native_cs_mask |= BIT(i);
2552         }
2553
2554         ctlr->unused_native_cs = ffz(native_cs_mask);
2555         if (num_cs_gpios && ctlr->max_native_cs &&
2556             ctlr->unused_native_cs >= ctlr->max_native_cs) {
2557                 dev_err(dev, "No unused native chip select available\n");
2558                 return -EINVAL;
2559         }
2560
2561         return 0;
2562 }
2563
2564 static int spi_controller_check_ops(struct spi_controller *ctlr)
2565 {
2566         /*
2567          * The controller may implement only the high-level SPI-memory like
2568          * operations if it does not support regular SPI transfers, and this is
2569          * valid use case.
2570          * If ->mem_ops is NULL, we request that at least one of the
2571          * ->transfer_xxx() method be implemented.
2572          */
2573         if (ctlr->mem_ops) {
2574                 if (!ctlr->mem_ops->exec_op)
2575                         return -EINVAL;
2576         } else if (!ctlr->transfer && !ctlr->transfer_one &&
2577                    !ctlr->transfer_one_message) {
2578                 return -EINVAL;
2579         }
2580
2581         return 0;
2582 }
2583
2584 /**
2585  * spi_register_controller - register SPI master or slave controller
2586  * @ctlr: initialized master, originally from spi_alloc_master() or
2587  *      spi_alloc_slave()
2588  * Context: can sleep
2589  *
2590  * SPI controllers connect to their drivers using some non-SPI bus,
2591  * such as the platform bus.  The final stage of probe() in that code
2592  * includes calling spi_register_controller() to hook up to this SPI bus glue.
2593  *
2594  * SPI controllers use board specific (often SOC specific) bus numbers,
2595  * and board-specific addressing for SPI devices combines those numbers
2596  * with chip select numbers.  Since SPI does not directly support dynamic
2597  * device identification, boards need configuration tables telling which
2598  * chip is at which address.
2599  *
2600  * This must be called from context that can sleep.  It returns zero on
2601  * success, else a negative error code (dropping the controller's refcount).
2602  * After a successful return, the caller is responsible for calling
2603  * spi_unregister_controller().
2604  *
2605  * Return: zero on success, else a negative error code.
2606  */
2607 int spi_register_controller(struct spi_controller *ctlr)
2608 {
2609         struct device           *dev = ctlr->dev.parent;
2610         struct boardinfo        *bi;
2611         int                     status;
2612         int                     id, first_dynamic;
2613
2614         if (!dev)
2615                 return -ENODEV;
2616
2617         /*
2618          * Make sure all necessary hooks are implemented before registering
2619          * the SPI controller.
2620          */
2621         status = spi_controller_check_ops(ctlr);
2622         if (status)
2623                 return status;
2624
2625         if (ctlr->bus_num >= 0) {
2626                 /* devices with a fixed bus num must check-in with the num */
2627                 mutex_lock(&board_lock);
2628                 id = idr_alloc(&spi_master_idr, ctlr, ctlr->bus_num,
2629                         ctlr->bus_num + 1, GFP_KERNEL);
2630                 mutex_unlock(&board_lock);
2631                 if (WARN(id < 0, "couldn't get idr"))
2632                         return id == -ENOSPC ? -EBUSY : id;
2633                 ctlr->bus_num = id;
2634         } else if (ctlr->dev.of_node) {
2635                 /* allocate dynamic bus number using Linux idr */
2636                 id = of_alias_get_id(ctlr->dev.of_node, "spi");
2637                 if (id >= 0) {
2638                         ctlr->bus_num = id;
2639                         mutex_lock(&board_lock);
2640                         id = idr_alloc(&spi_master_idr, ctlr, ctlr->bus_num,
2641                                        ctlr->bus_num + 1, GFP_KERNEL);
2642                         mutex_unlock(&board_lock);
2643                         if (WARN(id < 0, "couldn't get idr"))
2644                                 return id == -ENOSPC ? -EBUSY : id;
2645                 }
2646         }
2647         if (ctlr->bus_num < 0) {
2648                 first_dynamic = of_alias_get_highest_id("spi");
2649                 if (first_dynamic < 0)
2650                         first_dynamic = 0;
2651                 else
2652                         first_dynamic++;
2653
2654                 mutex_lock(&board_lock);
2655                 id = idr_alloc(&spi_master_idr, ctlr, first_dynamic,
2656                                0, GFP_KERNEL);
2657                 mutex_unlock(&board_lock);
2658                 if (WARN(id < 0, "couldn't get idr"))
2659                         return id;
2660                 ctlr->bus_num = id;
2661         }
2662         INIT_LIST_HEAD(&ctlr->queue);
2663         spin_lock_init(&ctlr->queue_lock);
2664         spin_lock_init(&ctlr->bus_lock_spinlock);
2665         mutex_init(&ctlr->bus_lock_mutex);
2666         mutex_init(&ctlr->io_mutex);
2667         ctlr->bus_lock_flag = 0;
2668         init_completion(&ctlr->xfer_completion);
2669         if (!ctlr->max_dma_len)
2670                 ctlr->max_dma_len = INT_MAX;
2671
2672         /* register the device, then userspace will see it.
2673          * registration fails if the bus ID is in use.
2674          */
2675         dev_set_name(&ctlr->dev, "spi%u", ctlr->bus_num);
2676
2677         if (!spi_controller_is_slave(ctlr)) {
2678                 if (ctlr->use_gpio_descriptors) {
2679                         status = spi_get_gpio_descs(ctlr);
2680                         if (status)
2681                                 goto free_bus_id;
2682                         /*
2683                          * A controller using GPIO descriptors always
2684                          * supports SPI_CS_HIGH if need be.
2685                          */
2686                         ctlr->mode_bits |= SPI_CS_HIGH;
2687                 } else {
2688                         /* Legacy code path for GPIOs from DT */
2689                         status = of_spi_get_gpio_numbers(ctlr);
2690                         if (status)
2691                                 goto free_bus_id;
2692                 }
2693         }
2694
2695         /*
2696          * Even if it's just one always-selected device, there must
2697          * be at least one chipselect.
2698          */
2699         if (!ctlr->num_chipselect) {
2700                 status = -EINVAL;
2701                 goto free_bus_id;
2702         }
2703
2704         status = device_add(&ctlr->dev);
2705         if (status < 0)
2706                 goto free_bus_id;
2707         dev_dbg(dev, "registered %s %s\n",
2708                         spi_controller_is_slave(ctlr) ? "slave" : "master",
2709                         dev_name(&ctlr->dev));
2710
2711         /*
2712          * If we're using a queued driver, start the queue. Note that we don't
2713          * need the queueing logic if the driver is only supporting high-level
2714          * memory operations.
2715          */
2716         if (ctlr->transfer) {
2717                 dev_info(dev, "controller is unqueued, this is deprecated\n");
2718         } else if (ctlr->transfer_one || ctlr->transfer_one_message) {
2719                 status = spi_controller_initialize_queue(ctlr);
2720                 if (status) {
2721                         device_del(&ctlr->dev);
2722                         goto free_bus_id;
2723                 }
2724         }
2725         /* add statistics */
2726         spin_lock_init(&ctlr->statistics.lock);
2727
2728         mutex_lock(&board_lock);
2729         list_add_tail(&ctlr->list, &spi_controller_list);
2730         list_for_each_entry(bi, &board_list, list)
2731                 spi_match_controller_to_boardinfo(ctlr, &bi->board_info);
2732         mutex_unlock(&board_lock);
2733
2734         /* Register devices from the device tree and ACPI */
2735         of_register_spi_devices(ctlr);
2736         acpi_register_spi_devices(ctlr);
2737         return status;
2738
2739 free_bus_id:
2740         mutex_lock(&board_lock);
2741         idr_remove(&spi_master_idr, ctlr->bus_num);
2742         mutex_unlock(&board_lock);
2743         return status;
2744 }
2745 EXPORT_SYMBOL_GPL(spi_register_controller);
2746
2747 static void devm_spi_unregister(struct device *dev, void *res)
2748 {
2749         spi_unregister_controller(*(struct spi_controller **)res);
2750 }
2751
2752 /**
2753  * devm_spi_register_controller - register managed SPI master or slave
2754  *      controller
2755  * @dev:    device managing SPI controller
2756  * @ctlr: initialized controller, originally from spi_alloc_master() or
2757  *      spi_alloc_slave()
2758  * Context: can sleep
2759  *
2760  * Register a SPI device as with spi_register_controller() which will
2761  * automatically be unregistered and freed.
2762  *
2763  * Return: zero on success, else a negative error code.
2764  */
2765 int devm_spi_register_controller(struct device *dev,
2766                                  struct spi_controller *ctlr)
2767 {
2768         struct spi_controller **ptr;
2769         int ret;
2770
2771         ptr = devres_alloc(devm_spi_unregister, sizeof(*ptr), GFP_KERNEL);
2772         if (!ptr)
2773                 return -ENOMEM;
2774
2775         ret = spi_register_controller(ctlr);
2776         if (!ret) {
2777                 *ptr = ctlr;
2778                 devres_add(dev, ptr);
2779         } else {
2780                 devres_free(ptr);
2781         }
2782
2783         return ret;
2784 }
2785 EXPORT_SYMBOL_GPL(devm_spi_register_controller);
2786
2787 static int __unregister(struct device *dev, void *null)
2788 {
2789         spi_unregister_device(to_spi_device(dev));
2790         return 0;
2791 }
2792
2793 /**
2794  * spi_unregister_controller - unregister SPI master or slave controller
2795  * @ctlr: the controller being unregistered
2796  * Context: can sleep
2797  *
2798  * This call is used only by SPI controller drivers, which are the
2799  * only ones directly touching chip registers.
2800  *
2801  * This must be called from context that can sleep.
2802  *
2803  * Note that this function also drops a reference to the controller.
2804  */
2805 void spi_unregister_controller(struct spi_controller *ctlr)
2806 {
2807         struct spi_controller *found;
2808         int id = ctlr->bus_num;
2809
2810         /* Prevent addition of new devices, unregister existing ones */
2811         if (IS_ENABLED(CONFIG_SPI_DYNAMIC))
2812                 mutex_lock(&spi_add_lock);
2813
2814         device_for_each_child(&ctlr->dev, NULL, __unregister);
2815
2816         /* First make sure that this controller was ever added */
2817         mutex_lock(&board_lock);
2818         found = idr_find(&spi_master_idr, id);
2819         mutex_unlock(&board_lock);
2820         if (ctlr->queued) {
2821                 if (spi_destroy_queue(ctlr))
2822                         dev_err(&ctlr->dev, "queue remove failed\n");
2823         }
2824         mutex_lock(&board_lock);
2825         list_del(&ctlr->list);
2826         mutex_unlock(&board_lock);
2827
2828         device_unregister(&ctlr->dev);
2829         /* free bus id */
2830         mutex_lock(&board_lock);
2831         if (found == ctlr)
2832                 idr_remove(&spi_master_idr, id);
2833         mutex_unlock(&board_lock);
2834
2835         if (IS_ENABLED(CONFIG_SPI_DYNAMIC))
2836                 mutex_unlock(&spi_add_lock);
2837 }
2838 EXPORT_SYMBOL_GPL(spi_unregister_controller);
2839
2840 int spi_controller_suspend(struct spi_controller *ctlr)
2841 {
2842         int ret;
2843
2844         /* Basically no-ops for non-queued controllers */
2845         if (!ctlr->queued)
2846                 return 0;
2847
2848         ret = spi_stop_queue(ctlr);
2849         if (ret)
2850                 dev_err(&ctlr->dev, "queue stop failed\n");
2851
2852         return ret;
2853 }
2854 EXPORT_SYMBOL_GPL(spi_controller_suspend);
2855
2856 int spi_controller_resume(struct spi_controller *ctlr)
2857 {
2858         int ret;
2859
2860         if (!ctlr->queued)
2861                 return 0;
2862
2863         ret = spi_start_queue(ctlr);
2864         if (ret)
2865                 dev_err(&ctlr->dev, "queue restart failed\n");
2866
2867         return ret;
2868 }
2869 EXPORT_SYMBOL_GPL(spi_controller_resume);
2870
2871 static int __spi_controller_match(struct device *dev, const void *data)
2872 {
2873         struct spi_controller *ctlr;
2874         const u16 *bus_num = data;
2875
2876         ctlr = container_of(dev, struct spi_controller, dev);
2877         return ctlr->bus_num == *bus_num;
2878 }
2879
2880 /**
2881  * spi_busnum_to_master - look up master associated with bus_num
2882  * @bus_num: the master's bus number
2883  * Context: can sleep
2884  *
2885  * This call may be used with devices that are registered after
2886  * arch init time.  It returns a refcounted pointer to the relevant
2887  * spi_controller (which the caller must release), or NULL if there is
2888  * no such master registered.
2889  *
2890  * Return: the SPI master structure on success, else NULL.
2891  */
2892 struct spi_controller *spi_busnum_to_master(u16 bus_num)
2893 {
2894         struct device           *dev;
2895         struct spi_controller   *ctlr = NULL;
2896
2897         dev = class_find_device(&spi_master_class, NULL, &bus_num,
2898                                 __spi_controller_match);
2899         if (dev)
2900                 ctlr = container_of(dev, struct spi_controller, dev);
2901         /* reference got in class_find_device */
2902         return ctlr;
2903 }
2904 EXPORT_SYMBOL_GPL(spi_busnum_to_master);
2905
2906 /*-------------------------------------------------------------------------*/
2907
2908 /* Core methods for SPI resource management */
2909
2910 /**
2911  * spi_res_alloc - allocate a spi resource that is life-cycle managed
2912  *                 during the processing of a spi_message while using
2913  *                 spi_transfer_one
2914  * @spi:     the spi device for which we allocate memory
2915  * @release: the release code to execute for this resource
2916  * @size:    size to alloc and return
2917  * @gfp:     GFP allocation flags
2918  *
2919  * Return: the pointer to the allocated data
2920  *
2921  * This may get enhanced in the future to allocate from a memory pool
2922  * of the @spi_device or @spi_controller to avoid repeated allocations.
2923  */
2924 void *spi_res_alloc(struct spi_device *spi,
2925                     spi_res_release_t release,
2926                     size_t size, gfp_t gfp)
2927 {
2928         struct spi_res *sres;
2929
2930         sres = kzalloc(sizeof(*sres) + size, gfp);
2931         if (!sres)
2932                 return NULL;
2933
2934         INIT_LIST_HEAD(&sres->entry);
2935         sres->release = release;
2936
2937         return sres->data;
2938 }
2939 EXPORT_SYMBOL_GPL(spi_res_alloc);
2940
2941 /**
2942  * spi_res_free - free an spi resource
2943  * @res: pointer to the custom data of a resource
2944  *
2945  */
2946 void spi_res_free(void *res)
2947 {
2948         struct spi_res *sres = container_of(res, struct spi_res, data);
2949
2950         if (!res)
2951                 return;
2952
2953         WARN_ON(!list_empty(&sres->entry));
2954         kfree(sres);
2955 }
2956 EXPORT_SYMBOL_GPL(spi_res_free);
2957
2958 /**
2959  * spi_res_add - add a spi_res to the spi_message
2960  * @message: the spi message
2961  * @res:     the spi_resource
2962  */
2963 void spi_res_add(struct spi_message *message, void *res)
2964 {
2965         struct spi_res *sres = container_of(res, struct spi_res, data);
2966
2967         WARN_ON(!list_empty(&sres->entry));
2968         list_add_tail(&sres->entry, &message->resources);
2969 }
2970 EXPORT_SYMBOL_GPL(spi_res_add);
2971
2972 /**
2973  * spi_res_release - release all spi resources for this message
2974  * @ctlr:  the @spi_controller
2975  * @message: the @spi_message
2976  */
2977 void spi_res_release(struct spi_controller *ctlr, struct spi_message *message)
2978 {
2979         struct spi_res *res, *tmp;
2980
2981         list_for_each_entry_safe_reverse(res, tmp, &message->resources, entry) {
2982                 if (res->release)
2983                         res->release(ctlr, message, res->data);
2984
2985                 list_del(&res->entry);
2986
2987                 kfree(res);
2988         }
2989 }
2990 EXPORT_SYMBOL_GPL(spi_res_release);
2991
2992 /*-------------------------------------------------------------------------*/
2993
2994 /* Core methods for spi_message alterations */
2995
2996 static void __spi_replace_transfers_release(struct spi_controller *ctlr,
2997                                             struct spi_message *msg,
2998                                             void *res)
2999 {
3000         struct spi_replaced_transfers *rxfer = res;
3001         size_t i;
3002
3003         /* call extra callback if requested */
3004         if (rxfer->release)
3005                 rxfer->release(ctlr, msg, res);
3006
3007         /* insert replaced transfers back into the message */
3008         list_splice(&rxfer->replaced_transfers, rxfer->replaced_after);
3009
3010         /* remove the formerly inserted entries */
3011         for (i = 0; i < rxfer->inserted; i++)
3012                 list_del(&rxfer->inserted_transfers[i].transfer_list);
3013 }
3014
3015 /**
3016  * spi_replace_transfers - replace transfers with several transfers
3017  *                         and register change with spi_message.resources
3018  * @msg:           the spi_message we work upon
3019  * @xfer_first:    the first spi_transfer we want to replace
3020  * @remove:        number of transfers to remove
3021  * @insert:        the number of transfers we want to insert instead
3022  * @release:       extra release code necessary in some circumstances
3023  * @extradatasize: extra data to allocate (with alignment guarantees
3024  *                 of struct @spi_transfer)
3025  * @gfp:           gfp flags
3026  *
3027  * Returns: pointer to @spi_replaced_transfers,
3028  *          PTR_ERR(...) in case of errors.
3029  */
3030 struct spi_replaced_transfers *spi_replace_transfers(
3031         struct spi_message *msg,
3032         struct spi_transfer *xfer_first,
3033         size_t remove,
3034         size_t insert,
3035         spi_replaced_release_t release,
3036         size_t extradatasize,
3037         gfp_t gfp)
3038 {
3039         struct spi_replaced_transfers *rxfer;
3040         struct spi_transfer *xfer;
3041         size_t i;
3042
3043         /* allocate the structure using spi_res */
3044         rxfer = spi_res_alloc(msg->spi, __spi_replace_transfers_release,
3045                               struct_size(rxfer, inserted_transfers, insert)
3046                               + extradatasize,
3047                               gfp);
3048         if (!rxfer)
3049                 return ERR_PTR(-ENOMEM);
3050
3051         /* the release code to invoke before running the generic release */
3052         rxfer->release = release;
3053
3054         /* assign extradata */
3055         if (extradatasize)
3056                 rxfer->extradata =
3057                         &rxfer->inserted_transfers[insert];
3058
3059         /* init the replaced_transfers list */
3060         INIT_LIST_HEAD(&rxfer->replaced_transfers);
3061
3062         /* assign the list_entry after which we should reinsert
3063          * the @replaced_transfers - it may be spi_message.messages!
3064          */
3065         rxfer->replaced_after = xfer_first->transfer_list.prev;
3066
3067         /* remove the requested number of transfers */
3068         for (i = 0; i < remove; i++) {
3069                 /* if the entry after replaced_after it is msg->transfers
3070                  * then we have been requested to remove more transfers
3071                  * than are in the list
3072                  */
3073                 if (rxfer->replaced_after->next == &msg->transfers) {
3074                         dev_err(&msg->spi->dev,
3075                                 "requested to remove more spi_transfers than are available\n");
3076                         /* insert replaced transfers back into the message */
3077                         list_splice(&rxfer->replaced_transfers,
3078                                     rxfer->replaced_after);
3079
3080                         /* free the spi_replace_transfer structure */
3081                         spi_res_free(rxfer);
3082
3083                         /* and return with an error */
3084                         return ERR_PTR(-EINVAL);
3085                 }
3086
3087                 /* remove the entry after replaced_after from list of
3088                  * transfers and add it to list of replaced_transfers
3089                  */
3090                 list_move_tail(rxfer->replaced_after->next,
3091                                &rxfer->replaced_transfers);
3092         }
3093
3094         /* create copy of the given xfer with identical settings
3095          * based on the first transfer to get removed
3096          */
3097         for (i = 0; i < insert; i++) {
3098                 /* we need to run in reverse order */
3099                 xfer = &rxfer->inserted_transfers[insert - 1 - i];
3100
3101                 /* copy all spi_transfer data */
3102                 memcpy(xfer, xfer_first, sizeof(*xfer));
3103
3104                 /* add to list */
3105                 list_add(&xfer->transfer_list, rxfer->replaced_after);
3106
3107                 /* clear cs_change and delay for all but the last */
3108                 if (i) {
3109                         xfer->cs_change = false;
3110                         xfer->delay_usecs = 0;
3111                         xfer->delay.value = 0;
3112                 }
3113         }
3114
3115         /* set up inserted */
3116         rxfer->inserted = insert;
3117
3118         /* and register it with spi_res/spi_message */
3119         spi_res_add(msg, rxfer);
3120
3121         return rxfer;
3122 }
3123 EXPORT_SYMBOL_GPL(spi_replace_transfers);
3124
3125 static int __spi_split_transfer_maxsize(struct spi_controller *ctlr,
3126                                         struct spi_message *msg,
3127                                         struct spi_transfer **xferp,
3128                                         size_t maxsize,
3129                                         gfp_t gfp)
3130 {
3131         struct spi_transfer *xfer = *xferp, *xfers;
3132         struct spi_replaced_transfers *srt;
3133         size_t offset;
3134         size_t count, i;
3135
3136         /* calculate how many we have to replace */
3137         count = DIV_ROUND_UP(xfer->len, maxsize);
3138
3139         /* create replacement */
3140         srt = spi_replace_transfers(msg, xfer, 1, count, NULL, 0, gfp);
3141         if (IS_ERR(srt))
3142                 return PTR_ERR(srt);
3143         xfers = srt->inserted_transfers;
3144
3145         /* now handle each of those newly inserted spi_transfers
3146          * note that the replacements spi_transfers all are preset
3147          * to the same values as *xferp, so tx_buf, rx_buf and len
3148          * are all identical (as well as most others)
3149          * so we just have to fix up len and the pointers.
3150          *
3151          * this also includes support for the depreciated
3152          * spi_message.is_dma_mapped interface
3153          */
3154
3155         /* the first transfer just needs the length modified, so we
3156          * run it outside the loop
3157          */
3158         xfers[0].len = min_t(size_t, maxsize, xfer[0].len);
3159
3160         /* all the others need rx_buf/tx_buf also set */
3161         for (i = 1, offset = maxsize; i < count; offset += maxsize, i++) {
3162                 /* update rx_buf, tx_buf and dma */
3163                 if (xfers[i].rx_buf)
3164                         xfers[i].rx_buf += offset;
3165                 if (xfers[i].rx_dma)
3166                         xfers[i].rx_dma += offset;
3167                 if (xfers[i].tx_buf)
3168                         xfers[i].tx_buf += offset;
3169                 if (xfers[i].tx_dma)
3170                         xfers[i].tx_dma += offset;
3171
3172                 /* update length */
3173                 xfers[i].len = min(maxsize, xfers[i].len - offset);
3174         }
3175
3176         /* we set up xferp to the last entry we have inserted,
3177          * so that we skip those already split transfers
3178          */
3179         *xferp = &xfers[count - 1];
3180
3181         /* increment statistics counters */
3182         SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics,
3183                                        transfers_split_maxsize);
3184         SPI_STATISTICS_INCREMENT_FIELD(&msg->spi->statistics,
3185                                        transfers_split_maxsize);
3186
3187         return 0;
3188 }
3189
3190 /**
3191  * spi_split_tranfers_maxsize - split spi transfers into multiple transfers
3192  *                              when an individual transfer exceeds a
3193  *                              certain size
3194  * @ctlr:    the @spi_controller for this transfer
3195  * @msg:   the @spi_message to transform
3196  * @maxsize:  the maximum when to apply this
3197  * @gfp: GFP allocation flags
3198  *
3199  * Return: status of transformation
3200  */
3201 int spi_split_transfers_maxsize(struct spi_controller *ctlr,
3202                                 struct spi_message *msg,
3203                                 size_t maxsize,
3204                                 gfp_t gfp)
3205 {
3206         struct spi_transfer *xfer;
3207         int ret;
3208
3209         /* iterate over the transfer_list,
3210          * but note that xfer is advanced to the last transfer inserted
3211          * to avoid checking sizes again unnecessarily (also xfer does
3212          * potentiall belong to a different list by the time the
3213          * replacement has happened
3214          */
3215         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
3216                 if (xfer->len > maxsize) {
3217                         ret = __spi_split_transfer_maxsize(ctlr, msg, &xfer,
3218                                                            maxsize, gfp);
3219                         if (ret)
3220                                 return ret;
3221                 }
3222         }
3223
3224         return 0;
3225 }
3226 EXPORT_SYMBOL_GPL(spi_split_transfers_maxsize);
3227
3228 /*-------------------------------------------------------------------------*/
3229
3230 /* Core methods for SPI controller protocol drivers.  Some of the
3231  * other core methods are currently defined as inline functions.
3232  */
3233
3234 static int __spi_validate_bits_per_word(struct spi_controller *ctlr,
3235                                         u8 bits_per_word)
3236 {
3237         if (ctlr->bits_per_word_mask) {
3238                 /* Only 32 bits fit in the mask */
3239                 if (bits_per_word > 32)
3240                         return -EINVAL;
3241                 if (!(ctlr->bits_per_word_mask & SPI_BPW_MASK(bits_per_word)))
3242                         return -EINVAL;
3243         }
3244
3245         return 0;
3246 }
3247
3248 /**
3249  * spi_setup - setup SPI mode and clock rate
3250  * @spi: the device whose settings are being modified
3251  * Context: can sleep, and no requests are queued to the device
3252  *
3253  * SPI protocol drivers may need to update the transfer mode if the
3254  * device doesn't work with its default.  They may likewise need
3255  * to update clock rates or word sizes from initial values.  This function
3256  * changes those settings, and must be called from a context that can sleep.
3257  * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
3258  * effect the next time the device is selected and data is transferred to
3259  * or from it.  When this function returns, the spi device is deselected.
3260  *
3261  * Note that this call will fail if the protocol driver specifies an option
3262  * that the underlying controller or its driver does not support.  For
3263  * example, not all hardware supports wire transfers using nine bit words,
3264  * LSB-first wire encoding, or active-high chipselects.
3265  *
3266  * Return: zero on success, else a negative error code.
3267  */
3268 int spi_setup(struct spi_device *spi)
3269 {
3270         unsigned        bad_bits, ugly_bits;
3271         int             status;
3272
3273         /* check mode to prevent that DUAL and QUAD set at the same time
3274          */
3275         if (((spi->mode & SPI_TX_DUAL) && (spi->mode & SPI_TX_QUAD)) ||
3276                 ((spi->mode & SPI_RX_DUAL) && (spi->mode & SPI_RX_QUAD))) {
3277                 dev_err(&spi->dev,
3278                 "setup: can not select dual and quad at the same time\n");
3279                 return -EINVAL;
3280         }
3281         /* if it is SPI_3WIRE mode, DUAL and QUAD should be forbidden
3282          */
3283         if ((spi->mode & SPI_3WIRE) && (spi->mode &
3284                 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_TX_OCTAL |
3285                  SPI_RX_DUAL | SPI_RX_QUAD | SPI_RX_OCTAL)))
3286                 return -EINVAL;
3287         /* help drivers fail *cleanly* when they need options
3288          * that aren't supported with their current controller
3289          * SPI_CS_WORD has a fallback software implementation,
3290          * so it is ignored here.
3291          */
3292         bad_bits = spi->mode & ~(spi->controller->mode_bits | SPI_CS_WORD);
3293         /* nothing prevents from working with active-high CS in case if it
3294          * is driven by GPIO.
3295          */
3296         if (gpio_is_valid(spi->cs_gpio))
3297                 bad_bits &= ~SPI_CS_HIGH;
3298         ugly_bits = bad_bits &
3299                     (SPI_TX_DUAL | SPI_TX_QUAD | SPI_TX_OCTAL |
3300                      SPI_RX_DUAL | SPI_RX_QUAD | SPI_RX_OCTAL);
3301         if (ugly_bits) {
3302                 dev_warn(&spi->dev,
3303                          "setup: ignoring unsupported mode bits %x\n",
3304                          ugly_bits);
3305                 spi->mode &= ~ugly_bits;
3306                 bad_bits &= ~ugly_bits;
3307         }
3308         if (bad_bits) {
3309                 dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
3310                         bad_bits);
3311                 return -EINVAL;
3312         }
3313
3314         if (!spi->bits_per_word)
3315                 spi->bits_per_word = 8;
3316
3317         status = __spi_validate_bits_per_word(spi->controller,
3318                                               spi->bits_per_word);
3319         if (status)
3320                 return status;
3321
3322         if (!spi->max_speed_hz)
3323                 spi->max_speed_hz = spi->controller->max_speed_hz;
3324
3325         if (spi->controller->setup)
3326                 status = spi->controller->setup(spi);
3327
3328         if (spi->controller->auto_runtime_pm && spi->controller->set_cs) {
3329                 status = pm_runtime_get_sync(spi->controller->dev.parent);
3330                 if (status < 0) {
3331                         pm_runtime_put_noidle(spi->controller->dev.parent);
3332                         dev_err(&spi->controller->dev, "Failed to power device: %d\n",
3333                                 status);
3334                         return status;
3335                 }
3336
3337                 /*
3338                  * We do not want to return positive value from pm_runtime_get,
3339                  * there are many instances of devices calling spi_setup() and
3340                  * checking for a non-zero return value instead of a negative
3341                  * return value.
3342                  */
3343                 status = 0;
3344
3345                 spi_set_cs(spi, false);
3346                 pm_runtime_mark_last_busy(spi->controller->dev.parent);
3347                 pm_runtime_put_autosuspend(spi->controller->dev.parent);
3348         } else {
3349                 spi_set_cs(spi, false);
3350         }
3351
3352         if (spi->rt && !spi->controller->rt) {
3353                 spi->controller->rt = true;
3354                 spi_set_thread_rt(spi->controller);
3355         }
3356
3357         dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
3358                         (int) (spi->mode & (SPI_CPOL | SPI_CPHA)),
3359                         (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
3360                         (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
3361                         (spi->mode & SPI_3WIRE) ? "3wire, " : "",
3362                         (spi->mode & SPI_LOOP) ? "loopback, " : "",
3363                         spi->bits_per_word, spi->max_speed_hz,
3364                         status);
3365
3366         return status;
3367 }
3368 EXPORT_SYMBOL_GPL(spi_setup);
3369
3370 /**
3371  * spi_set_cs_timing - configure CS setup, hold, and inactive delays
3372  * @spi: the device that requires specific CS timing configuration
3373  * @setup: CS setup time specified via @spi_delay
3374  * @hold: CS hold time specified via @spi_delay
3375  * @inactive: CS inactive delay between transfers specified via @spi_delay
3376  *
3377  * Return: zero on success, else a negative error code.
3378  */
3379 int spi_set_cs_timing(struct spi_device *spi, struct spi_delay *setup,
3380                       struct spi_delay *hold, struct spi_delay *inactive)
3381 {
3382         size_t len;
3383
3384         if (spi->controller->set_cs_timing)
3385                 return spi->controller->set_cs_timing(spi, setup, hold,
3386                                                       inactive);
3387
3388         if ((setup && setup->unit == SPI_DELAY_UNIT_SCK) ||
3389             (hold && hold->unit == SPI_DELAY_UNIT_SCK) ||
3390             (inactive && inactive->unit == SPI_DELAY_UNIT_SCK)) {
3391                 dev_err(&spi->dev,
3392                         "Clock-cycle delays for CS not supported in SW mode\n");
3393                 return -ENOTSUPP;
3394         }
3395
3396         len = sizeof(struct spi_delay);
3397
3398         /* copy delays to controller */
3399         if (setup)
3400                 memcpy(&spi->controller->cs_setup, setup, len);
3401         else
3402                 memset(&spi->controller->cs_setup, 0, len);
3403
3404         if (hold)
3405                 memcpy(&spi->controller->cs_hold, hold, len);
3406         else
3407                 memset(&spi->controller->cs_hold, 0, len);
3408
3409         if (inactive)
3410                 memcpy(&spi->controller->cs_inactive, inactive, len);
3411         else
3412                 memset(&spi->controller->cs_inactive, 0, len);
3413
3414         return 0;
3415 }
3416 EXPORT_SYMBOL_GPL(spi_set_cs_timing);
3417
3418 static int _spi_xfer_word_delay_update(struct spi_transfer *xfer,
3419                                        struct spi_device *spi)
3420 {
3421         int delay1, delay2;
3422
3423         delay1 = spi_delay_to_ns(&xfer->word_delay, xfer);
3424         if (delay1 < 0)
3425                 return delay1;
3426
3427         delay2 = spi_delay_to_ns(&spi->word_delay, xfer);
3428         if (delay2 < 0)
3429                 return delay2;
3430
3431         if (delay1 < delay2)
3432                 memcpy(&xfer->word_delay, &spi->word_delay,
3433                        sizeof(xfer->word_delay));
3434
3435         return 0;
3436 }
3437
3438 static int __spi_validate(struct spi_device *spi, struct spi_message *message)
3439 {
3440         struct spi_controller *ctlr = spi->controller;
3441         struct spi_transfer *xfer;
3442         int w_size;
3443
3444         if (list_empty(&message->transfers))
3445                 return -EINVAL;
3446
3447         /* If an SPI controller does not support toggling the CS line on each
3448          * transfer (indicated by the SPI_CS_WORD flag) or we are using a GPIO
3449          * for the CS line, we can emulate the CS-per-word hardware function by
3450          * splitting transfers into one-word transfers and ensuring that
3451          * cs_change is set for each transfer.
3452          */
3453         if ((spi->mode & SPI_CS_WORD) && (!(ctlr->mode_bits & SPI_CS_WORD) ||
3454                                           spi->cs_gpiod ||
3455                                           gpio_is_valid(spi->cs_gpio))) {
3456                 size_t maxsize;
3457                 int ret;
3458
3459                 maxsize = (spi->bits_per_word + 7) / 8;
3460
3461                 /* spi_split_transfers_maxsize() requires message->spi */
3462                 message->spi = spi;
3463
3464                 ret = spi_split_transfers_maxsize(ctlr, message, maxsize,
3465                                                   GFP_KERNEL);
3466                 if (ret)
3467                         return ret;
3468
3469                 list_for_each_entry(xfer, &message->transfers, transfer_list) {
3470                         /* don't change cs_change on the last entry in the list */
3471                         if (list_is_last(&xfer->transfer_list, &message->transfers))
3472                                 break;
3473                         xfer->cs_change = 1;
3474                 }
3475         }
3476
3477         /* Half-duplex links include original MicroWire, and ones with
3478          * only one data pin like SPI_3WIRE (switches direction) or where
3479          * either MOSI or MISO is missing.  They can also be caused by
3480          * software limitations.
3481          */
3482         if ((ctlr->flags & SPI_CONTROLLER_HALF_DUPLEX) ||
3483             (spi->mode & SPI_3WIRE)) {
3484                 unsigned flags = ctlr->flags;
3485
3486                 list_for_each_entry(xfer, &message->transfers, transfer_list) {
3487                         if (xfer->rx_buf && xfer->tx_buf)
3488                                 return -EINVAL;
3489                         if ((flags & SPI_CONTROLLER_NO_TX) && xfer->tx_buf)
3490                                 return -EINVAL;
3491                         if ((flags & SPI_CONTROLLER_NO_RX) && xfer->rx_buf)
3492                                 return -EINVAL;
3493                 }
3494         }
3495
3496         /**
3497          * Set transfer bits_per_word and max speed as spi device default if
3498          * it is not set for this transfer.
3499          * Set transfer tx_nbits and rx_nbits as single transfer default
3500          * (SPI_NBITS_SINGLE) if it is not set for this transfer.
3501          * Ensure transfer word_delay is at least as long as that required by
3502          * device itself.
3503          */
3504         message->frame_length = 0;
3505         list_for_each_entry(xfer, &message->transfers, transfer_list) {
3506                 xfer->effective_speed_hz = 0;
3507                 message->frame_length += xfer->len;
3508                 if (!xfer->bits_per_word)
3509                         xfer->bits_per_word = spi->bits_per_word;
3510
3511                 if (!xfer->speed_hz)
3512                         xfer->speed_hz = spi->max_speed_hz;
3513
3514                 if (ctlr->max_speed_hz && xfer->speed_hz > ctlr->max_speed_hz)
3515                         xfer->speed_hz = ctlr->max_speed_hz;
3516
3517                 if (__spi_validate_bits_per_word(ctlr, xfer->bits_per_word))
3518                         return -EINVAL;
3519
3520                 /*
3521                  * SPI transfer length should be multiple of SPI word size
3522                  * where SPI word size should be power-of-two multiple
3523                  */
3524                 if (xfer->bits_per_word <= 8)
3525                         w_size = 1;
3526                 else if (xfer->bits_per_word <= 16)
3527                         w_size = 2;
3528                 else
3529                         w_size = 4;
3530
3531                 /* No partial transfers accepted */
3532                 if (xfer->len % w_size)
3533                         return -EINVAL;
3534
3535                 if (xfer->speed_hz && ctlr->min_speed_hz &&
3536                     xfer->speed_hz < ctlr->min_speed_hz)
3537                         return -EINVAL;
3538
3539                 if (xfer->tx_buf && !xfer->tx_nbits)
3540                         xfer->tx_nbits = SPI_NBITS_SINGLE;
3541                 if (xfer->rx_buf && !xfer->rx_nbits)
3542                         xfer->rx_nbits = SPI_NBITS_SINGLE;
3543                 /* check transfer tx/rx_nbits:
3544                  * 1. check the value matches one of single, dual and quad
3545                  * 2. check tx/rx_nbits match the mode in spi_device
3546                  */
3547                 if (xfer->tx_buf) {
3548                         if (xfer->tx_nbits != SPI_NBITS_SINGLE &&
3549                                 xfer->tx_nbits != SPI_NBITS_DUAL &&
3550                                 xfer->tx_nbits != SPI_NBITS_QUAD)
3551                                 return -EINVAL;
3552                         if ((xfer->tx_nbits == SPI_NBITS_DUAL) &&
3553                                 !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
3554                                 return -EINVAL;
3555                         if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
3556                                 !(spi->mode & SPI_TX_QUAD))
3557                                 return -EINVAL;
3558                 }
3559                 /* check transfer rx_nbits */
3560                 if (xfer->rx_buf) {
3561                         if (xfer->rx_nbits != SPI_NBITS_SINGLE &&
3562                                 xfer->rx_nbits != SPI_NBITS_DUAL &&
3563                                 xfer->rx_nbits != SPI_NBITS_QUAD)
3564                                 return -EINVAL;
3565                         if ((xfer->rx_nbits == SPI_NBITS_DUAL) &&
3566                                 !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
3567                                 return -EINVAL;
3568                         if ((xfer->rx_nbits == SPI_NBITS_QUAD) &&
3569                                 !(spi->mode & SPI_RX_QUAD))
3570                                 return -EINVAL;
3571                 }
3572
3573                 if (_spi_xfer_word_delay_update(xfer, spi))
3574                         return -EINVAL;
3575         }
3576
3577         message->status = -EINPROGRESS;
3578
3579         return 0;
3580 }
3581
3582 static int __spi_async(struct spi_device *spi, struct spi_message *message)
3583 {
3584         struct spi_controller *ctlr = spi->controller;
3585         struct spi_transfer *xfer;
3586
3587         /*
3588          * Some controllers do not support doing regular SPI transfers. Return
3589          * ENOTSUPP when this is the case.
3590          */
3591         if (!ctlr->transfer)
3592                 return -ENOTSUPP;
3593
3594         message->spi = spi;
3595
3596         SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics, spi_async);
3597         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_async);
3598
3599         trace_spi_message_submit(message);
3600
3601         if (!ctlr->ptp_sts_supported) {
3602                 list_for_each_entry(xfer, &message->transfers, transfer_list) {
3603                         xfer->ptp_sts_word_pre = 0;
3604                         ptp_read_system_prets(xfer->ptp_sts);
3605                 }
3606         }
3607
3608         return ctlr->transfer(spi, message);
3609 }
3610
3611 /**
3612  * spi_async - asynchronous SPI transfer
3613  * @spi: device with which data will be exchanged
3614  * @message: describes the data transfers, including completion callback
3615  * Context: any (irqs may be blocked, etc)
3616  *
3617  * This call may be used in_irq and other contexts which can't sleep,
3618  * as well as from task contexts which can sleep.
3619  *
3620  * The completion callback is invoked in a context which can't sleep.
3621  * Before that invocation, the value of message->status is undefined.
3622  * When the callback is issued, message->status holds either zero (to
3623  * indicate complete success) or a negative error code.  After that
3624  * callback returns, the driver which issued the transfer request may
3625  * deallocate the associated memory; it's no longer in use by any SPI
3626  * core or controller driver code.
3627  *
3628  * Note that although all messages to a spi_device are handled in
3629  * FIFO order, messages may go to different devices in other orders.
3630  * Some device might be higher priority, or have various "hard" access
3631  * time requirements, for example.
3632  *
3633  * On detection of any fault during the transfer, processing of
3634  * the entire message is aborted, and the device is deselected.
3635  * Until returning from the associated message completion callback,
3636  * no other spi_message queued to that device will be processed.
3637  * (This rule applies equally to all the synchronous transfer calls,
3638  * which are wrappers around this core asynchronous primitive.)
3639  *
3640  * Return: zero on success, else a negative error code.
3641  */
3642 int spi_async(struct spi_device *spi, struct spi_message *message)
3643 {
3644         struct spi_controller *ctlr = spi->controller;
3645         int ret;
3646         unsigned long flags;
3647
3648         ret = __spi_validate(spi, message);
3649         if (ret != 0)
3650                 return ret;
3651
3652         spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
3653
3654         if (ctlr->bus_lock_flag)
3655                 ret = -EBUSY;
3656         else
3657                 ret = __spi_async(spi, message);
3658
3659         spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3660
3661         return ret;
3662 }
3663 EXPORT_SYMBOL_GPL(spi_async);
3664
3665 /**
3666  * spi_async_locked - version of spi_async with exclusive bus usage
3667  * @spi: device with which data will be exchanged
3668  * @message: describes the data transfers, including completion callback
3669  * Context: any (irqs may be blocked, etc)
3670  *
3671  * This call may be used in_irq and other contexts which can't sleep,
3672  * as well as from task contexts which can sleep.
3673  *
3674  * The completion callback is invoked in a context which can't sleep.
3675  * Before that invocation, the value of message->status is undefined.
3676  * When the callback is issued, message->status holds either zero (to
3677  * indicate complete success) or a negative error code.  After that
3678  * callback returns, the driver which issued the transfer request may
3679  * deallocate the associated memory; it's no longer in use by any SPI
3680  * core or controller driver code.
3681  *
3682  * Note that although all messages to a spi_device are handled in
3683  * FIFO order, messages may go to different devices in other orders.
3684  * Some device might be higher priority, or have various "hard" access
3685  * time requirements, for example.
3686  *
3687  * On detection of any fault during the transfer, processing of
3688  * the entire message is aborted, and the device is deselected.
3689  * Until returning from the associated message completion callback,
3690  * no other spi_message queued to that device will be processed.
3691  * (This rule applies equally to all the synchronous transfer calls,
3692  * which are wrappers around this core asynchronous primitive.)
3693  *
3694  * Return: zero on success, else a negative error code.
3695  */
3696 int spi_async_locked(struct spi_device *spi, struct spi_message *message)
3697 {
3698         struct spi_controller *ctlr = spi->controller;
3699         int ret;
3700         unsigned long flags;
3701
3702         ret = __spi_validate(spi, message);
3703         if (ret != 0)
3704                 return ret;
3705
3706         spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
3707
3708         ret = __spi_async(spi, message);
3709
3710         spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3711
3712         return ret;
3713
3714 }
3715 EXPORT_SYMBOL_GPL(spi_async_locked);
3716
3717 /*-------------------------------------------------------------------------*/
3718
3719 /* Utility methods for SPI protocol drivers, layered on
3720  * top of the core.  Some other utility methods are defined as
3721  * inline functions.
3722  */
3723
3724 static void spi_complete(void *arg)
3725 {
3726         complete(arg);
3727 }
3728
3729 static int __spi_sync(struct spi_device *spi, struct spi_message *message)
3730 {
3731         DECLARE_COMPLETION_ONSTACK(done);
3732         int status;
3733         struct spi_controller *ctlr = spi->controller;
3734         unsigned long flags;
3735
3736         status = __spi_validate(spi, message);
3737         if (status != 0)
3738                 return status;
3739
3740         message->complete = spi_complete;
3741         message->context = &done;
3742         message->spi = spi;
3743
3744         SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics, spi_sync);
3745         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_sync);
3746
3747         /* If we're not using the legacy transfer method then we will
3748          * try to transfer in the calling context so special case.
3749          * This code would be less tricky if we could remove the
3750          * support for driver implemented message queues.
3751          */
3752         if (ctlr->transfer == spi_queued_transfer) {
3753                 spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
3754
3755                 trace_spi_message_submit(message);
3756
3757                 status = __spi_queued_transfer(spi, message, false);
3758
3759                 spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3760         } else {
3761                 status = spi_async_locked(spi, message);
3762         }
3763
3764         if (status == 0) {
3765                 /* Push out the messages in the calling context if we
3766                  * can.
3767                  */
3768                 if (ctlr->transfer == spi_queued_transfer) {
3769                         SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics,
3770                                                        spi_sync_immediate);
3771                         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics,
3772                                                        spi_sync_immediate);
3773                         __spi_pump_messages(ctlr, false);
3774                 }
3775
3776                 wait_for_completion(&done);
3777                 status = message->status;
3778         }
3779         message->context = NULL;
3780         return status;
3781 }
3782
3783 /**
3784  * spi_sync - blocking/synchronous SPI data transfers
3785  * @spi: device with which data will be exchanged
3786  * @message: describes the data transfers
3787  * Context: can sleep
3788  *
3789  * This call may only be used from a context that may sleep.  The sleep
3790  * is non-interruptible, and has no timeout.  Low-overhead controller
3791  * drivers may DMA directly into and out of the message buffers.
3792  *
3793  * Note that the SPI device's chip select is active during the message,
3794  * and then is normally disabled between messages.  Drivers for some
3795  * frequently-used devices may want to minimize costs of selecting a chip,
3796  * by leaving it selected in anticipation that the next message will go
3797  * to the same chip.  (That may increase power usage.)
3798  *
3799  * Also, the caller is guaranteeing that the memory associated with the
3800  * message will not be freed before this call returns.
3801  *
3802  * Return: zero on success, else a negative error code.
3803  */
3804 int spi_sync(struct spi_device *spi, struct spi_message *message)
3805 {
3806         int ret;
3807
3808         mutex_lock(&spi->controller->bus_lock_mutex);
3809         ret = __spi_sync(spi, message);
3810         mutex_unlock(&spi->controller->bus_lock_mutex);
3811
3812         return ret;
3813 }
3814 EXPORT_SYMBOL_GPL(spi_sync);
3815
3816 /**
3817  * spi_sync_locked - version of spi_sync with exclusive bus usage
3818  * @spi: device with which data will be exchanged
3819  * @message: describes the data transfers
3820  * Context: can sleep
3821  *
3822  * This call may only be used from a context that may sleep.  The sleep
3823  * is non-interruptible, and has no timeout.  Low-overhead controller
3824  * drivers may DMA directly into and out of the message buffers.
3825  *
3826  * This call should be used by drivers that require exclusive access to the
3827  * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
3828  * be released by a spi_bus_unlock call when the exclusive access is over.
3829  *
3830  * Return: zero on success, else a negative error code.
3831  */
3832 int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
3833 {
3834         return __spi_sync(spi, message);
3835 }
3836 EXPORT_SYMBOL_GPL(spi_sync_locked);
3837
3838 /**
3839  * spi_bus_lock - obtain a lock for exclusive SPI bus usage
3840  * @ctlr: SPI bus master that should be locked for exclusive bus access
3841  * Context: can sleep
3842  *
3843  * This call may only be used from a context that may sleep.  The sleep
3844  * is non-interruptible, and has no timeout.
3845  *
3846  * This call should be used by drivers that require exclusive access to the
3847  * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
3848  * exclusive access is over. Data transfer must be done by spi_sync_locked
3849  * and spi_async_locked calls when the SPI bus lock is held.
3850  *
3851  * Return: always zero.
3852  */
3853 int spi_bus_lock(struct spi_controller *ctlr)
3854 {
3855         unsigned long flags;
3856
3857         mutex_lock(&ctlr->bus_lock_mutex);
3858
3859         spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
3860         ctlr->bus_lock_flag = 1;
3861         spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3862
3863         /* mutex remains locked until spi_bus_unlock is called */
3864
3865         return 0;
3866 }
3867 EXPORT_SYMBOL_GPL(spi_bus_lock);
3868
3869 /**
3870  * spi_bus_unlock - release the lock for exclusive SPI bus usage
3871  * @ctlr: SPI bus master that was locked for exclusive bus access
3872  * Context: can sleep
3873  *
3874  * This call may only be used from a context that may sleep.  The sleep
3875  * is non-interruptible, and has no timeout.
3876  *
3877  * This call releases an SPI bus lock previously obtained by an spi_bus_lock
3878  * call.
3879  *
3880  * Return: always zero.
3881  */
3882 int spi_bus_unlock(struct spi_controller *ctlr)
3883 {
3884         ctlr->bus_lock_flag = 0;
3885
3886         mutex_unlock(&ctlr->bus_lock_mutex);
3887
3888         return 0;
3889 }
3890 EXPORT_SYMBOL_GPL(spi_bus_unlock);
3891
3892 /* portable code must never pass more than 32 bytes */
3893 #define SPI_BUFSIZ      max(32, SMP_CACHE_BYTES)
3894
3895 static u8       *buf;
3896
3897 /**
3898  * spi_write_then_read - SPI synchronous write followed by read
3899  * @spi: device with which data will be exchanged
3900  * @txbuf: data to be written (need not be dma-safe)
3901  * @n_tx: size of txbuf, in bytes
3902  * @rxbuf: buffer into which data will be read (need not be dma-safe)
3903  * @n_rx: size of rxbuf, in bytes
3904  * Context: can sleep
3905  *
3906  * This performs a half duplex MicroWire style transaction with the
3907  * device, sending txbuf and then reading rxbuf.  The return value
3908  * is zero for success, else a negative errno status code.
3909  * This call may only be used from a context that may sleep.
3910  *
3911  * Parameters to this routine are always copied using a small buffer.
3912  * Performance-sensitive or bulk transfer code should instead use
3913  * spi_{async,sync}() calls with dma-safe buffers.
3914  *
3915  * Return: zero on success, else a negative error code.
3916  */
3917 int spi_write_then_read(struct spi_device *spi,
3918                 const void *txbuf, unsigned n_tx,
3919                 void *rxbuf, unsigned n_rx)
3920 {
3921         static DEFINE_MUTEX(lock);
3922
3923         int                     status;
3924         struct spi_message      message;
3925         struct spi_transfer     x[2];
3926         u8                      *local_buf;
3927
3928         /* Use preallocated DMA-safe buffer if we can.  We can't avoid
3929          * copying here, (as a pure convenience thing), but we can
3930          * keep heap costs out of the hot path unless someone else is
3931          * using the pre-allocated buffer or the transfer is too large.
3932          */
3933         if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) {
3934                 local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx),
3935                                     GFP_KERNEL | GFP_DMA);
3936                 if (!local_buf)
3937                         return -ENOMEM;
3938         } else {
3939                 local_buf = buf;
3940         }
3941
3942         spi_message_init(&message);
3943         memset(x, 0, sizeof(x));
3944         if (n_tx) {
3945                 x[0].len = n_tx;
3946                 spi_message_add_tail(&x[0], &message);
3947         }
3948         if (n_rx) {
3949                 x[1].len = n_rx;
3950                 spi_message_add_tail(&x[1], &message);
3951         }
3952
3953         memcpy(local_buf, txbuf, n_tx);
3954         x[0].tx_buf = local_buf;
3955         x[1].rx_buf = local_buf + n_tx;
3956
3957         /* do the i/o */
3958         status = spi_sync(spi, &message);
3959         if (status == 0)
3960                 memcpy(rxbuf, x[1].rx_buf, n_rx);
3961
3962         if (x[0].tx_buf == buf)
3963                 mutex_unlock(&lock);
3964         else
3965                 kfree(local_buf);
3966
3967         return status;
3968 }
3969 EXPORT_SYMBOL_GPL(spi_write_then_read);
3970
3971 /*-------------------------------------------------------------------------*/
3972
3973 #if IS_ENABLED(CONFIG_OF)
3974 /* must call put_device() when done with returned spi_device device */
3975 struct spi_device *of_find_spi_device_by_node(struct device_node *node)
3976 {
3977         struct device *dev = bus_find_device_by_of_node(&spi_bus_type, node);
3978
3979         return dev ? to_spi_device(dev) : NULL;
3980 }
3981 EXPORT_SYMBOL_GPL(of_find_spi_device_by_node);
3982 #endif /* IS_ENABLED(CONFIG_OF) */
3983
3984 #if IS_ENABLED(CONFIG_OF_DYNAMIC)
3985 /* the spi controllers are not using spi_bus, so we find it with another way */
3986 static struct spi_controller *of_find_spi_controller_by_node(struct device_node *node)
3987 {
3988         struct device *dev;
3989
3990         dev = class_find_device_by_of_node(&spi_master_class, node);
3991         if (!dev && IS_ENABLED(CONFIG_SPI_SLAVE))
3992                 dev = class_find_device_by_of_node(&spi_slave_class, node);
3993         if (!dev)
3994                 return NULL;
3995
3996         /* reference got in class_find_device */
3997         return container_of(dev, struct spi_controller, dev);
3998 }
3999
4000 static int of_spi_notify(struct notifier_block *nb, unsigned long action,
4001                          void *arg)
4002 {
4003         struct of_reconfig_data *rd = arg;
4004         struct spi_controller *ctlr;
4005         struct spi_device *spi;
4006
4007         switch (of_reconfig_get_state_change(action, arg)) {
4008         case OF_RECONFIG_CHANGE_ADD:
4009                 ctlr = of_find_spi_controller_by_node(rd->dn->parent);
4010                 if (ctlr == NULL)
4011                         return NOTIFY_OK;       /* not for us */
4012
4013                 if (of_node_test_and_set_flag(rd->dn, OF_POPULATED)) {
4014                         put_device(&ctlr->dev);
4015                         return NOTIFY_OK;
4016                 }
4017
4018                 spi = of_register_spi_device(ctlr, rd->dn);
4019                 put_device(&ctlr->dev);
4020
4021                 if (IS_ERR(spi)) {
4022                         pr_err("%s: failed to create for '%pOF'\n",
4023                                         __func__, rd->dn);
4024                         of_node_clear_flag(rd->dn, OF_POPULATED);
4025                         return notifier_from_errno(PTR_ERR(spi));
4026                 }
4027                 break;
4028
4029         case OF_RECONFIG_CHANGE_REMOVE:
4030                 /* already depopulated? */
4031                 if (!of_node_check_flag(rd->dn, OF_POPULATED))
4032                         return NOTIFY_OK;
4033
4034                 /* find our device by node */
4035                 spi = of_find_spi_device_by_node(rd->dn);
4036                 if (spi == NULL)
4037                         return NOTIFY_OK;       /* no? not meant for us */
4038
4039                 /* unregister takes one ref away */
4040                 spi_unregister_device(spi);
4041
4042                 /* and put the reference of the find */
4043                 put_device(&spi->dev);
4044                 break;
4045         }
4046
4047         return NOTIFY_OK;
4048 }
4049
4050 static struct notifier_block spi_of_notifier = {
4051         .notifier_call = of_spi_notify,
4052 };
4053 #else /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
4054 extern struct notifier_block spi_of_notifier;
4055 #endif /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
4056
4057 #if IS_ENABLED(CONFIG_ACPI)
4058 static int spi_acpi_controller_match(struct device *dev, const void *data)
4059 {
4060         return ACPI_COMPANION(dev->parent) == data;
4061 }
4062
4063 static struct spi_controller *acpi_spi_find_controller_by_adev(struct acpi_device *adev)
4064 {
4065         struct device *dev;
4066
4067         dev = class_find_device(&spi_master_class, NULL, adev,
4068                                 spi_acpi_controller_match);
4069         if (!dev && IS_ENABLED(CONFIG_SPI_SLAVE))
4070                 dev = class_find_device(&spi_slave_class, NULL, adev,
4071                                         spi_acpi_controller_match);
4072         if (!dev)
4073                 return NULL;
4074
4075         return container_of(dev, struct spi_controller, dev);
4076 }
4077
4078 static struct spi_device *acpi_spi_find_device_by_adev(struct acpi_device *adev)
4079 {
4080         struct device *dev;
4081
4082         dev = bus_find_device_by_acpi_dev(&spi_bus_type, adev);
4083         return to_spi_device(dev);
4084 }
4085
4086 static int acpi_spi_notify(struct notifier_block *nb, unsigned long value,
4087                            void *arg)
4088 {
4089         struct acpi_device *adev = arg;
4090         struct spi_controller *ctlr;
4091         struct spi_device *spi;
4092
4093         switch (value) {
4094         case ACPI_RECONFIG_DEVICE_ADD:
4095                 ctlr = acpi_spi_find_controller_by_adev(adev->parent);
4096                 if (!ctlr)
4097                         break;
4098
4099                 acpi_register_spi_device(ctlr, adev);
4100                 put_device(&ctlr->dev);
4101                 break;
4102         case ACPI_RECONFIG_DEVICE_REMOVE:
4103                 if (!acpi_device_enumerated(adev))
4104                         break;
4105
4106                 spi = acpi_spi_find_device_by_adev(adev);
4107                 if (!spi)
4108                         break;
4109
4110                 spi_unregister_device(spi);
4111                 put_device(&spi->dev);
4112                 break;
4113         }
4114
4115         return NOTIFY_OK;
4116 }
4117
4118 static struct notifier_block spi_acpi_notifier = {
4119         .notifier_call = acpi_spi_notify,
4120 };
4121 #else
4122 extern struct notifier_block spi_acpi_notifier;
4123 #endif
4124
4125 static int __init spi_init(void)
4126 {
4127         int     status;
4128
4129         buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
4130         if (!buf) {
4131                 status = -ENOMEM;
4132                 goto err0;
4133         }
4134
4135         status = bus_register(&spi_bus_type);
4136         if (status < 0)
4137                 goto err1;
4138
4139         status = class_register(&spi_master_class);
4140         if (status < 0)
4141                 goto err2;
4142
4143         if (IS_ENABLED(CONFIG_SPI_SLAVE)) {
4144                 status = class_register(&spi_slave_class);
4145                 if (status < 0)
4146                         goto err3;
4147         }
4148
4149         if (IS_ENABLED(CONFIG_OF_DYNAMIC))
4150                 WARN_ON(of_reconfig_notifier_register(&spi_of_notifier));
4151         if (IS_ENABLED(CONFIG_ACPI))
4152                 WARN_ON(acpi_reconfig_notifier_register(&spi_acpi_notifier));
4153
4154         return 0;
4155
4156 err3:
4157         class_unregister(&spi_master_class);
4158 err2:
4159         bus_unregister(&spi_bus_type);
4160 err1:
4161         kfree(buf);
4162         buf = NULL;
4163 err0:
4164         return status;
4165 }
4166
4167 /* board_info is normally registered in arch_initcall(),
4168  * but even essential drivers wait till later
4169  *
4170  * REVISIT only boardinfo really needs static linking. the rest (device and
4171  * driver registration) _could_ be dynamically linked (modular) ... costs
4172  * include needing to have boardinfo data structures be much more public.
4173  */
4174 postcore_initcall(spi_init);