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
  40 #include "internals.h"
  41
  42 static DEFINE_IDR(spi_master_idr);
  43
  44 static void spidev_release(struct device *dev)
  45 {
  46         struct spi_device       *spi = to_spi_device(dev);
  47
  48         /* spi controllers may cleanup for released devices */
  49         if (spi->controller->cleanup)
  50                 spi->controller->cleanup(spi);
  51
  52         spi_controller_put(spi->controller);
  53         kfree(spi->driver_override);
  54         kfree(spi);
  55 }
  56
  57 static ssize_t
  58 modalias_show(struct device *dev, struct device_attribute *a, char *buf)
  59 {
  60         const struct spi_device *spi = to_spi_device(dev);
  61         int len;
  62
  63         len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1);
  64         if (len != -ENODEV)
  65                 return len;
  66
  67         return sprintf(buf, "%s%s\n", SPI_MODULE_PREFIX, spi->modalias);
  68 }
  69 static DEVICE_ATTR_RO(modalias);
  70
  71 static ssize_t driver_override_store(struct device *dev,
  72                                      struct device_attribute *a,
  73                                      const char *buf, size_t count)
  74 {
  75         struct spi_device *spi = to_spi_device(dev);
  76         const char *end = memchr(buf, '\n', count);
  77         const size_t len = end ? end - buf : count;
  78         const char *driver_override, *old;
  79
  80         /* We need to keep extra room for a newline when displaying value */
  81         if (len >= (PAGE_SIZE - 1))
  82                 return -EINVAL;
  83
  84         driver_override = kstrndup(buf, len, GFP_KERNEL);
  85         if (!driver_override)
  86                 return -ENOMEM;
  87
  88         device_lock(dev);
  89         old = spi->driver_override;
  90         if (len) {
  91                 spi->driver_override = driver_override;
  92         } else {
  93                 /* Emptry string, disable driver override */
  94                 spi->driver_override = NULL;
  95                 kfree(driver_override);
  96         }
  97         device_unlock(dev);
  98         kfree(old);
  99
 100         return count;
 101 }
 102
 103 static ssize_t driver_override_show(struct device *dev,
 104                                     struct device_attribute *a, char *buf)
 105 {
 106         const struct spi_device *spi = to_spi_device(dev);
 107         ssize_t len;
 108
 109         device_lock(dev);
 110         len = snprintf(buf, PAGE_SIZE, "%s\n", spi->driver_override ? : "");
 111         device_unlock(dev);
 112         return len;
 113 }
 114 static DEVICE_ATTR_RW(driver_override);
 115
 116 #define SPI_STATISTICS_ATTRS(field, file)                               \
 117 static ssize_t spi_controller_##field##_show(struct device *dev,        \
 118                                              struct device_attribute *attr, \
 119                                              char *buf)                 \
 120 {                                                                       \
 121         struct spi_controller *ctlr = container_of(dev,                 \
 122                                          struct spi_controller, dev);   \
 123         return spi_statistics_##field##_show(&ctlr->statistics, buf);   \
 124 }                                                                       \
 125 static struct device_attribute dev_attr_spi_controller_##field = {      \
 126         .attr = { .name = file, .mode = 0444 },                         \
 127         .show = spi_controller_##field##_show,                          \
 128 };                                                                      \
 129 static ssize_t spi_device_##field##_show(struct device *dev,            \
 130                                          struct device_attribute *attr, \
 131                                         char *buf)                      \
 132 {                                                                       \
 133         struct spi_device *spi = to_spi_device(dev);                    \
 134         return spi_statistics_##field##_show(&spi->statistics, buf);    \
 135 }                                                                       \
 136 static struct device_attribute dev_attr_spi_device_##field = {          \
 137         .attr = { .name = file, .mode = 0444 },                         \
 138         .show = spi_device_##field##_show,                              \
 139 }
 140
 141 #define SPI_STATISTICS_SHOW_NAME(name, file, field, format_string)      \
 142 static ssize_t spi_statistics_##name##_show(struct spi_statistics *stat, \
 143                                             char *buf)                  \
 144 {                                                                       \
 145         unsigned long flags;                                            \
 146         ssize_t len;                                                    \
 147         spin_lock_irqsave(&stat->lock, flags);                          \
 148         len = sprintf(buf, format_string, stat->field);                 \
 149         spin_unlock_irqrestore(&stat->lock, flags);                     \
 150         return len;                                                     \
 151 }                                                                       \
 152 SPI_STATISTICS_ATTRS(name, file)
 153
 154 #define SPI_STATISTICS_SHOW(field, format_string)                       \
 155         SPI_STATISTICS_SHOW_NAME(field, __stringify(field),             \
 156                                  field, format_string)
 157
 158 SPI_STATISTICS_SHOW(messages, "%lu");
 159 SPI_STATISTICS_SHOW(transfers, "%lu");
 160 SPI_STATISTICS_SHOW(errors, "%lu");
 161 SPI_STATISTICS_SHOW(timedout, "%lu");
 162
 163 SPI_STATISTICS_SHOW(spi_sync, "%lu");
 164 SPI_STATISTICS_SHOW(spi_sync_immediate, "%lu");
 165 SPI_STATISTICS_SHOW(spi_async, "%lu");
 166
 167 SPI_STATISTICS_SHOW(bytes, "%llu");
 168 SPI_STATISTICS_SHOW(bytes_rx, "%llu");
 169 SPI_STATISTICS_SHOW(bytes_tx, "%llu");
 170
 171 #define SPI_STATISTICS_TRANSFER_BYTES_HISTO(index, number)              \
 172         SPI_STATISTICS_SHOW_NAME(transfer_bytes_histo##index,           \
 173                                  "transfer_bytes_histo_" number,        \
 174                                  transfer_bytes_histo[index],  "%lu")
 175 SPI_STATISTICS_TRANSFER_BYTES_HISTO(0,  "0-1");
 176 SPI_STATISTICS_TRANSFER_BYTES_HISTO(1,  "2-3");
 177 SPI_STATISTICS_TRANSFER_BYTES_HISTO(2,  "4-7");
 178 SPI_STATISTICS_TRANSFER_BYTES_HISTO(3,  "8-15");
 179 SPI_STATISTICS_TRANSFER_BYTES_HISTO(4,  "16-31");
 180 SPI_STATISTICS_TRANSFER_BYTES_HISTO(5,  "32-63");
 181 SPI_STATISTICS_TRANSFER_BYTES_HISTO(6,  "64-127");
 182 SPI_STATISTICS_TRANSFER_BYTES_HISTO(7,  "128-255");
 183 SPI_STATISTICS_TRANSFER_BYTES_HISTO(8,  "256-511");
 184 SPI_STATISTICS_TRANSFER_BYTES_HISTO(9,  "512-1023");
 185 SPI_STATISTICS_TRANSFER_BYTES_HISTO(10, "1024-2047");
 186 SPI_STATISTICS_TRANSFER_BYTES_HISTO(11, "2048-4095");
 187 SPI_STATISTICS_TRANSFER_BYTES_HISTO(12, "4096-8191");
 188 SPI_STATISTICS_TRANSFER_BYTES_HISTO(13, "8192-16383");
 189 SPI_STATISTICS_TRANSFER_BYTES_HISTO(14, "16384-32767");
 190 SPI_STATISTICS_TRANSFER_BYTES_HISTO(15, "32768-65535");
 191 SPI_STATISTICS_TRANSFER_BYTES_HISTO(16, "65536+");
 192
 193 SPI_STATISTICS_SHOW(transfers_split_maxsize, "%lu");
 194
 195 static struct attribute *spi_dev_attrs[] = {
 196         &dev_attr_modalias.attr,
 197         &dev_attr_driver_override.attr,
 198         NULL,
 199 };
 200
 201 static const struct attribute_group spi_dev_group = {
 202         .attrs  = spi_dev_attrs,
 203 };
 204
 205 static struct attribute *spi_device_statistics_attrs[] = {
 206         &dev_attr_spi_device_messages.attr,
 207         &dev_attr_spi_device_transfers.attr,
 208         &dev_attr_spi_device_errors.attr,
 209         &dev_attr_spi_device_timedout.attr,
 210         &dev_attr_spi_device_spi_sync.attr,
 211         &dev_attr_spi_device_spi_sync_immediate.attr,
 212         &dev_attr_spi_device_spi_async.attr,
 213         &dev_attr_spi_device_bytes.attr,
 214         &dev_attr_spi_device_bytes_rx.attr,
 215         &dev_attr_spi_device_bytes_tx.attr,
 216         &dev_attr_spi_device_transfer_bytes_histo0.attr,
 217         &dev_attr_spi_device_transfer_bytes_histo1.attr,
 218         &dev_attr_spi_device_transfer_bytes_histo2.attr,
 219         &dev_attr_spi_device_transfer_bytes_histo3.attr,
 220         &dev_attr_spi_device_transfer_bytes_histo4.attr,
 221         &dev_attr_spi_device_transfer_bytes_histo5.attr,
 222         &dev_attr_spi_device_transfer_bytes_histo6.attr,
 223         &dev_attr_spi_device_transfer_bytes_histo7.attr,
 224         &dev_attr_spi_device_transfer_bytes_histo8.attr,
 225         &dev_attr_spi_device_transfer_bytes_histo9.attr,
 226         &dev_attr_spi_device_transfer_bytes_histo10.attr,
 227         &dev_attr_spi_device_transfer_bytes_histo11.attr,
 228         &dev_attr_spi_device_transfer_bytes_histo12.attr,
 229         &dev_attr_spi_device_transfer_bytes_histo13.attr,
 230         &dev_attr_spi_device_transfer_bytes_histo14.attr,
 231         &dev_attr_spi_device_transfer_bytes_histo15.attr,
 232         &dev_attr_spi_device_transfer_bytes_histo16.attr,
 233         &dev_attr_spi_device_transfers_split_maxsize.attr,
 234         NULL,
 235 };
 236
 237 static const struct attribute_group spi_device_statistics_group = {
 238         .name  = "statistics",
 239         .attrs  = spi_device_statistics_attrs,
 240 };
 241
 242 static const struct attribute_group *spi_dev_groups[] = {
 243         &spi_dev_group,
 244         &spi_device_statistics_group,
 245         NULL,
 246 };
 247
 248 static struct attribute *spi_controller_statistics_attrs[] = {
 249         &dev_attr_spi_controller_messages.attr,
 250         &dev_attr_spi_controller_transfers.attr,
 251         &dev_attr_spi_controller_errors.attr,
 252         &dev_attr_spi_controller_timedout.attr,
 253         &dev_attr_spi_controller_spi_sync.attr,
 254         &dev_attr_spi_controller_spi_sync_immediate.attr,
 255         &dev_attr_spi_controller_spi_async.attr,
 256         &dev_attr_spi_controller_bytes.attr,
 257         &dev_attr_spi_controller_bytes_rx.attr,
 258         &dev_attr_spi_controller_bytes_tx.attr,
 259         &dev_attr_spi_controller_transfer_bytes_histo0.attr,
 260         &dev_attr_spi_controller_transfer_bytes_histo1.attr,
 261         &dev_attr_spi_controller_transfer_bytes_histo2.attr,
 262         &dev_attr_spi_controller_transfer_bytes_histo3.attr,
 263         &dev_attr_spi_controller_transfer_bytes_histo4.attr,
 264         &dev_attr_spi_controller_transfer_bytes_histo5.attr,
 265         &dev_attr_spi_controller_transfer_bytes_histo6.attr,
 266         &dev_attr_spi_controller_transfer_bytes_histo7.attr,
 267         &dev_attr_spi_controller_transfer_bytes_histo8.attr,
 268         &dev_attr_spi_controller_transfer_bytes_histo9.attr,
 269         &dev_attr_spi_controller_transfer_bytes_histo10.attr,
 270         &dev_attr_spi_controller_transfer_bytes_histo11.attr,
 271         &dev_attr_spi_controller_transfer_bytes_histo12.attr,
 272         &dev_attr_spi_controller_transfer_bytes_histo13.attr,
 273         &dev_attr_spi_controller_transfer_bytes_histo14.attr,
 274         &dev_attr_spi_controller_transfer_bytes_histo15.attr,
 275         &dev_attr_spi_controller_transfer_bytes_histo16.attr,
 276         &dev_attr_spi_controller_transfers_split_maxsize.attr,
 277         NULL,
 278 };
 279
 280 static const struct attribute_group spi_controller_statistics_group = {
 281         .name  = "statistics",
 282         .attrs  = spi_controller_statistics_attrs,
 283 };
 284
 285 static const struct attribute_group *spi_master_groups[] = {
 286         &spi_controller_statistics_group,
 287         NULL,
 288 };
 289
 290 void spi_statistics_add_transfer_stats(struct spi_statistics *stats,
 291                                        struct spi_transfer *xfer,
 292                                        struct spi_controller *ctlr)
 293 {
 294         unsigned long flags;
 295         int l2len = min(fls(xfer->len), SPI_STATISTICS_HISTO_SIZE) - 1;
 296
 297         if (l2len < 0)
 298                 l2len = 0;
 299
 300         spin_lock_irqsave(&stats->lock, flags);
 301
 302         stats->transfers++;
 303         stats->transfer_bytes_histo[l2len]++;
 304
 305         stats->bytes += xfer->len;
 306         if ((xfer->tx_buf) &&
 307             (xfer->tx_buf != ctlr->dummy_tx))
 308                 stats->bytes_tx += xfer->len;
 309         if ((xfer->rx_buf) &&
 310             (xfer->rx_buf != ctlr->dummy_rx))
 311                 stats->bytes_rx += xfer->len;
 312
 313         spin_unlock_irqrestore(&stats->lock, flags);
 314 }
 315 EXPORT_SYMBOL_GPL(spi_statistics_add_transfer_stats);
 316
 317 /* modalias support makes "modprobe $MODALIAS" new-style hotplug work,
 318  * and the sysfs version makes coldplug work too.
 319  */
 320
 321 static const struct spi_device_id *spi_match_id(const struct spi_device_id *id,
 322                                                 const struct spi_device *sdev)
 323 {
 324         while (id->name[0]) {
 325                 if (!strcmp(sdev->modalias, id->name))
 326                         return id;
 327                 id++;
 328         }
 329         return NULL;
 330 }
 331
 332 const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev)
 333 {
 334         const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver);
 335
 336         return spi_match_id(sdrv->id_table, sdev);
 337 }
 338 EXPORT_SYMBOL_GPL(spi_get_device_id);
 339
 340 static int spi_match_device(struct device *dev, struct device_driver *drv)
 341 {
 342         const struct spi_device *spi = to_spi_device(dev);
 343         const struct spi_driver *sdrv = to_spi_driver(drv);
 344
 345         /* Check override first, and if set, only use the named driver */
 346         if (spi->driver_override)
 347                 return strcmp(spi->driver_override, drv->name) == 0;
 348
 349         /* Attempt an OF style match */
 350         if (of_driver_match_device(dev, drv))
 351                 return 1;
 352
 353         /* Then try ACPI */
 354         if (acpi_driver_match_device(dev, drv))
 355                 return 1;
 356
 357         if (sdrv->id_table)
 358                 return !!spi_match_id(sdrv->id_table, spi);
 359
 360         return strcmp(spi->modalias, drv->name) == 0;
 361 }
 362
 363 static int spi_uevent(struct device *dev, struct kobj_uevent_env *env)
 364 {
 365         const struct spi_device         *spi = to_spi_device(dev);
 366         int rc;
 367
 368         rc = acpi_device_uevent_modalias(dev, env);
 369         if (rc != -ENODEV)
 370                 return rc;
 371
 372         return add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias);
 373 }
 374
 375 struct bus_type spi_bus_type = {
 376         .name           = "spi",
 377         .dev_groups     = spi_dev_groups,
 378         .match          = spi_match_device,
 379         .uevent         = spi_uevent,
 380 };
 381 EXPORT_SYMBOL_GPL(spi_bus_type);
 382
 383
 384 static int spi_drv_probe(struct device *dev)
 385 {
 386         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
 387         struct spi_device               *spi = to_spi_device(dev);
 388         int ret;
 389
 390         ret = of_clk_set_defaults(dev->of_node, false);
 391         if (ret)
 392                 return ret;
 393
 394         if (dev->of_node) {
 395                 spi->irq = of_irq_get(dev->of_node, 0);
 396                 if (spi->irq == -EPROBE_DEFER)
 397                         return -EPROBE_DEFER;
 398                 if (spi->irq < 0)
 399                         spi->irq = 0;
 400         }
 401
 402         ret = dev_pm_domain_attach(dev, true);
 403         if (ret)
 404                 return ret;
 405
 406         ret = sdrv->probe(spi);
 407         if (ret)
 408                 dev_pm_domain_detach(dev, true);
 409
 410         return ret;
 411 }
 412
 413 static int spi_drv_remove(struct device *dev)
 414 {
 415         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
 416         int ret;
 417
 418         ret = sdrv->remove(to_spi_device(dev));
 419         dev_pm_domain_detach(dev, true);
 420
 421         return ret;
 422 }
 423
 424 static void spi_drv_shutdown(struct device *dev)
 425 {
 426         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
 427
 428         sdrv->shutdown(to_spi_device(dev));
 429 }
 430
 431 /**
 432  * __spi_register_driver - register a SPI driver
 433  * @owner: owner module of the driver to register
 434  * @sdrv: the driver to register
 435  * Context: can sleep
 436  *
 437  * Return: zero on success, else a negative error code.
 438  */
 439 int __spi_register_driver(struct module *owner, struct spi_driver *sdrv)
 440 {
 441         sdrv->driver.owner = owner;
 442         sdrv->driver.bus = &spi_bus_type;
 443         if (sdrv->probe)
 444                 sdrv->driver.probe = spi_drv_probe;
 445         if (sdrv->remove)
 446                 sdrv->driver.remove = spi_drv_remove;
 447         if (sdrv->shutdown)
 448                 sdrv->driver.shutdown = spi_drv_shutdown;
 449         return driver_register(&sdrv->driver);
 450 }
 451 EXPORT_SYMBOL_GPL(__spi_register_driver);
 452
 453 /*-------------------------------------------------------------------------*/
 454
 455 /* SPI devices should normally not be created by SPI device drivers; that
 456  * would make them board-specific.  Similarly with SPI controller drivers.
 457  * Device registration normally goes into like arch/.../mach.../board-YYY.c
 458  * with other readonly (flashable) information about mainboard devices.
 459  */
 460
 461 struct boardinfo {
 462         struct list_head        list;
 463         struct spi_board_info   board_info;
 464 };
 465
 466 static LIST_HEAD(board_list);
 467 static LIST_HEAD(spi_controller_list);
 468
 469 /*
 470  * Used to protect add/del opertion for board_info list and
 471  * spi_controller list, and their matching process
 472  * also used to protect object of type struct idr
 473  */
 474 static DEFINE_MUTEX(board_lock);
 475
 476 /**
 477  * spi_alloc_device - Allocate a new SPI device
 478  * @ctlr: Controller to which device is connected
 479  * Context: can sleep
 480  *
 481  * Allows a driver to allocate and initialize a spi_device without
 482  * registering it immediately.  This allows a driver to directly
 483  * fill the spi_device with device parameters before calling
 484  * spi_add_device() on it.
 485  *
 486  * Caller is responsible to call spi_add_device() on the returned
 487  * spi_device structure to add it to the SPI controller.  If the caller
 488  * needs to discard the spi_device without adding it, then it should
 489  * call spi_dev_put() on it.
 490  *
 491  * Return: a pointer to the new device, or NULL.
 492  */
 493 struct spi_device *spi_alloc_device(struct spi_controller *ctlr)
 494 {
 495         struct spi_device       *spi;
 496
 497         if (!spi_controller_get(ctlr))
 498                 return NULL;
 499
 500         spi = kzalloc(sizeof(*spi), GFP_KERNEL);
 501         if (!spi) {
 502                 spi_controller_put(ctlr);
 503                 return NULL;
 504         }
 505
 506         spi->master = spi->controller = ctlr;
 507         spi->dev.parent = &ctlr->dev;
 508         spi->dev.bus = &spi_bus_type;
 509         spi->dev.release = spidev_release;
 510         spi->cs_gpio = -ENOENT;
 511
 512         spin_lock_init(&spi->statistics.lock);
 513
 514         device_initialize(&spi->dev);
 515         return spi;
 516 }
 517 EXPORT_SYMBOL_GPL(spi_alloc_device);
 518
 519 static void spi_dev_set_name(struct spi_device *spi)
 520 {
 521         struct acpi_device *adev = ACPI_COMPANION(&spi->dev);
 522
 523         if (adev) {
 524                 dev_set_name(&spi->dev, "spi-%s", acpi_dev_name(adev));
 525                 return;
 526         }
 527
 528         dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->controller->dev),
 529                      spi->chip_select);
 530 }
 531
 532 static int spi_dev_check(struct device *dev, void *data)
 533 {
 534         struct spi_device *spi = to_spi_device(dev);
 535         struct spi_device *new_spi = data;
 536
 537         if (spi->controller == new_spi->controller &&
 538             spi->chip_select == new_spi->chip_select)
 539                 return -EBUSY;
 540         return 0;
 541 }
 542
 543 /**
 544  * spi_add_device - Add spi_device allocated with spi_alloc_device
 545  * @spi: spi_device to register
 546  *
 547  * Companion function to spi_alloc_device.  Devices allocated with
 548  * spi_alloc_device can be added onto the spi bus with this function.
 549  *
 550  * Return: 0 on success; negative errno on failure
 551  */
 552 int spi_add_device(struct spi_device *spi)
 553 {
 554         static DEFINE_MUTEX(spi_add_lock);
 555         struct spi_controller *ctlr = spi->controller;
 556         struct device *dev = ctlr->dev.parent;
 557         int status;
 558
 559         /* Chipselects are numbered 0..max; validate. */
 560         if (spi->chip_select >= ctlr->num_chipselect) {
 561                 dev_err(dev, "cs%d >= max %d\n", spi->chip_select,
 562                         ctlr->num_chipselect);
 563                 return -EINVAL;
 564         }
 565
 566         /* Set the bus ID string */
 567         spi_dev_set_name(spi);
 568
 569         /* We need to make sure there's no other device with this
 570          * chipselect **BEFORE** we call setup(), else we'll trash
 571          * its configuration.  Lock against concurrent add() calls.
 572          */
 573         mutex_lock(&spi_add_lock);
 574
 575         status = bus_for_each_dev(&spi_bus_type, NULL, spi, spi_dev_check);
 576         if (status) {
 577                 dev_err(dev, "chipselect %d already in use\n",
 578                                 spi->chip_select);
 579                 goto done;
 580         }
 581
 582         /* Descriptors take precedence */
 583         if (ctlr->cs_gpiods)
 584                 spi->cs_gpiod = ctlr->cs_gpiods[spi->chip_select];
 585         else if (ctlr->cs_gpios)
 586                 spi->cs_gpio = ctlr->cs_gpios[spi->chip_select];
 587
 588         /* Drivers may modify this initial i/o setup, but will
 589          * normally rely on the device being setup.  Devices
 590          * using SPI_CS_HIGH can't coexist well otherwise...
 591          */
 592         status = spi_setup(spi);
 593         if (status < 0) {
 594                 dev_err(dev, "can't setup %s, status %d\n",
 595                                 dev_name(&spi->dev), status);
 596                 goto done;
 597         }
 598
 599         /* Device may be bound to an active driver when this returns */
 600         status = device_add(&spi->dev);
 601         if (status < 0)
 602                 dev_err(dev, "can't add %s, status %d\n",
 603                                 dev_name(&spi->dev), status);
 604         else
 605                 dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
 606
 607 done:
 608         mutex_unlock(&spi_add_lock);
 609         return status;
 610 }
 611 EXPORT_SYMBOL_GPL(spi_add_device);
 612
 613 /**
 614  * spi_new_device - instantiate one new SPI device
 615  * @ctlr: Controller to which device is connected
 616  * @chip: Describes the SPI device
 617  * Context: can sleep
 618  *
 619  * On typical mainboards, this is purely internal; and it's not needed
 620  * after board init creates the hard-wired devices.  Some development
 621  * platforms may not be able to use spi_register_board_info though, and
 622  * this is exported so that for example a USB or parport based adapter
 623  * driver could add devices (which it would learn about out-of-band).
 624  *
 625  * Return: the new device, or NULL.
 626  */
 627 struct spi_device *spi_new_device(struct spi_controller *ctlr,
 628                                   struct spi_board_info *chip)
 629 {
 630         struct spi_device       *proxy;
 631         int                     status;
 632
 633         /* NOTE:  caller did any chip->bus_num checks necessary.
 634          *
 635          * Also, unless we change the return value convention to use
 636          * error-or-pointer (not NULL-or-pointer), troubleshootability
 637          * suggests syslogged diagnostics are best here (ugh).
 638          */
 639
 640         proxy = spi_alloc_device(ctlr);
 641         if (!proxy)
 642                 return NULL;
 643
 644         WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
 645
 646         proxy->chip_select = chip->chip_select;
 647         proxy->max_speed_hz = chip->max_speed_hz;
 648         proxy->mode = chip->mode;
 649         proxy->irq = chip->irq;
 650         strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
 651         proxy->dev.platform_data = (void *) chip->platform_data;
 652         proxy->controller_data = chip->controller_data;
 653         proxy->controller_state = NULL;
 654
 655         if (chip->properties) {
 656                 status = device_add_properties(&proxy->dev, chip->properties);
 657                 if (status) {
 658                         dev_err(&ctlr->dev,
 659                                 "failed to add properties to '%s': %d\n",
 660                                 chip->modalias, status);
 661                         goto err_dev_put;
 662                 }
 663         }
 664
 665         status = spi_add_device(proxy);
 666         if (status < 0)
 667                 goto err_remove_props;
 668
 669         return proxy;
 670
 671 err_remove_props:
 672         if (chip->properties)
 673                 device_remove_properties(&proxy->dev);
 674 err_dev_put:
 675         spi_dev_put(proxy);
 676         return NULL;
 677 }
 678 EXPORT_SYMBOL_GPL(spi_new_device);
 679
 680 /**
 681  * spi_unregister_device - unregister a single SPI device
 682  * @spi: spi_device to unregister
 683  *
 684  * Start making the passed SPI device vanish. Normally this would be handled
 685  * by spi_unregister_controller().
 686  */
 687 void spi_unregister_device(struct spi_device *spi)
 688 {
 689         if (!spi)
 690                 return;
 691
 692         if (spi->dev.of_node) {
 693                 of_node_clear_flag(spi->dev.of_node, OF_POPULATED);
 694                 of_node_put(spi->dev.of_node);
 695         }
 696         if (ACPI_COMPANION(&spi->dev))
 697                 acpi_device_clear_enumerated(ACPI_COMPANION(&spi->dev));
 698         device_unregister(&spi->dev);
 699 }
 700 EXPORT_SYMBOL_GPL(spi_unregister_device);
 701
 702 static void spi_match_controller_to_boardinfo(struct spi_controller *ctlr,
 703                                               struct spi_board_info *bi)
 704 {
 705         struct spi_device *dev;
 706
 707         if (ctlr->bus_num != bi->bus_num)
 708                 return;
 709
 710         dev = spi_new_device(ctlr, bi);
 711         if (!dev)
 712                 dev_err(ctlr->dev.parent, "can't create new device for %s\n",
 713                         bi->modalias);
 714 }
 715
 716 /**
 717  * spi_register_board_info - register SPI devices for a given board
 718  * @info: array of chip descriptors
 719  * @n: how many descriptors are provided
 720  * Context: can sleep
 721  *
 722  * Board-specific early init code calls this (probably during arch_initcall)
 723  * with segments of the SPI device table.  Any device nodes are created later,
 724  * after the relevant parent SPI controller (bus_num) is defined.  We keep
 725  * this table of devices forever, so that reloading a controller driver will
 726  * not make Linux forget about these hard-wired devices.
 727  *
 728  * Other code can also call this, e.g. a particular add-on board might provide
 729  * SPI devices through its expansion connector, so code initializing that board
 730  * would naturally declare its SPI devices.
 731  *
 732  * The board info passed can safely be __initdata ... but be careful of
 733  * any embedded pointers (platform_data, etc), they're copied as-is.
 734  * Device properties are deep-copied though.
 735  *
 736  * Return: zero on success, else a negative error code.
 737  */
 738 int spi_register_board_info(struct spi_board_info const *info, unsigned n)
 739 {
 740         struct boardinfo *bi;
 741         int i;
 742
 743         if (!n)
 744                 return 0;
 745
 746         bi = kcalloc(n, sizeof(*bi), GFP_KERNEL);
 747         if (!bi)
 748                 return -ENOMEM;
 749
 750         for (i = 0; i < n; i++, bi++, info++) {
 751                 struct spi_controller *ctlr;
 752
 753                 memcpy(&bi->board_info, info, sizeof(*info));
 754                 if (info->properties) {
 755                         bi->board_info.properties =
 756                                         property_entries_dup(info->properties);
 757                         if (IS_ERR(bi->board_info.properties))
 758                                 return PTR_ERR(bi->board_info.properties);
 759                 }
 760
 761                 mutex_lock(&board_lock);
 762                 list_add_tail(&bi->list, &board_list);
 763                 list_for_each_entry(ctlr, &spi_controller_list, list)
 764                         spi_match_controller_to_boardinfo(ctlr,
 765                                                           &bi->board_info);
 766                 mutex_unlock(&board_lock);
 767         }
 768
 769         return 0;
 770 }
 771
 772 /*-------------------------------------------------------------------------*/
 773
 774 static void spi_set_cs(struct spi_device *spi, bool enable)
 775 {
 776         if (spi->mode & SPI_CS_HIGH)
 777                 enable = !enable;
 778
 779         if (spi->cs_gpiod || gpio_is_valid(spi->cs_gpio)) {
 780                 /*
 781                  * Honour the SPI_NO_CS flag and invert the enable line, as
 782                  * active low is default for SPI. Execution paths that handle
 783                  * polarity inversion in gpiolib (such as device tree) will
 784                  * enforce active high using the SPI_CS_HIGH resulting in a
 785                  * double inversion through the code above.
 786                  */
 787                 if (!(spi->mode & SPI_NO_CS)) {
 788                         if (spi->cs_gpiod)
 789                                 gpiod_set_value_cansleep(spi->cs_gpiod,
 790                                                          !enable);
 791                         else
 792                                 gpio_set_value_cansleep(spi->cs_gpio, !enable);
 793                 }
 794                 /* Some SPI masters need both GPIO CS & slave_select */
 795                 if ((spi->controller->flags & SPI_MASTER_GPIO_SS) &&
 796                     spi->controller->set_cs)
 797                         spi->controller->set_cs(spi, !enable);
 798         } else if (spi->controller->set_cs) {
 799                 spi->controller->set_cs(spi, !enable);
 800         }
 801 }
 802
 803 #ifdef CONFIG_HAS_DMA
 804 int spi_map_buf(struct spi_controller *ctlr, struct device *dev,
 805                 struct sg_table *sgt, void *buf, size_t len,
 806                 enum dma_data_direction dir)
 807 {
 808         const bool vmalloced_buf = is_vmalloc_addr(buf);
 809         unsigned int max_seg_size = dma_get_max_seg_size(dev);
 810 #ifdef CONFIG_HIGHMEM
 811         const bool kmap_buf = ((unsigned long)buf >= PKMAP_BASE &&
 812                                 (unsigned long)buf < (PKMAP_BASE +
 813                                         (LAST_PKMAP * PAGE_SIZE)));
 814 #else
 815         const bool kmap_buf = false;
 816 #endif
 817         int desc_len;
 818         int sgs;
 819         struct page *vm_page;
 820         struct scatterlist *sg;
 821         void *sg_buf;
 822         size_t min;
 823         int i, ret;
 824
 825         if (vmalloced_buf || kmap_buf) {
 826                 desc_len = min_t(int, max_seg_size, PAGE_SIZE);
 827                 sgs = DIV_ROUND_UP(len + offset_in_page(buf), desc_len);
 828         } else if (virt_addr_valid(buf)) {
 829                 desc_len = min_t(int, max_seg_size, ctlr->max_dma_len);
 830                 sgs = DIV_ROUND_UP(len, desc_len);
 831         } else {
 832                 return -EINVAL;
 833         }
 834
 835         ret = sg_alloc_table(sgt, sgs, GFP_KERNEL);
 836         if (ret != 0)
 837                 return ret;
 838
 839         sg = &sgt->sgl[0];
 840         for (i = 0; i < sgs; i++) {
 841
 842                 if (vmalloced_buf || kmap_buf) {
 843                         /*
 844                          * Next scatterlist entry size is the minimum between
 845                          * the desc_len and the remaining buffer length that
 846                          * fits in a page.
 847                          */
 848                         min = min_t(size_t, desc_len,
 849                                     min_t(size_t, len,
 850                                           PAGE_SIZE - offset_in_page(buf)));
 851                         if (vmalloced_buf)
 852                                 vm_page = vmalloc_to_page(buf);
 853                         else
 854                                 vm_page = kmap_to_page(buf);
 855                         if (!vm_page) {
 856                                 sg_free_table(sgt);
 857                                 return -ENOMEM;
 858                         }
 859                         sg_set_page(sg, vm_page,
 860                                     min, offset_in_page(buf));
 861                 } else {
 862                         min = min_t(size_t, len, desc_len);
 863                         sg_buf = buf;
 864                         sg_set_buf(sg, sg_buf, min);
 865                 }
 866
 867                 buf += min;
 868                 len -= min;
 869                 sg = sg_next(sg);
 870         }
 871
 872         ret = dma_map_sg(dev, sgt->sgl, sgt->nents, dir);
 873         if (!ret)
 874                 ret = -ENOMEM;
 875         if (ret < 0) {
 876                 sg_free_table(sgt);
 877                 return ret;
 878         }
 879
 880         sgt->nents = ret;
 881
 882         return 0;
 883 }
 884
 885 void spi_unmap_buf(struct spi_controller *ctlr, struct device *dev,
 886                    struct sg_table *sgt, enum dma_data_direction dir)
 887 {
 888         if (sgt->orig_nents) {
 889                 dma_unmap_sg(dev, sgt->sgl, sgt->orig_nents, dir);
 890                 sg_free_table(sgt);
 891         }
 892 }
 893
 894 static int __spi_map_msg(struct spi_controller *ctlr, struct spi_message *msg)
 895 {
 896         struct device *tx_dev, *rx_dev;
 897         struct spi_transfer *xfer;
 898         int ret;
 899
 900         if (!ctlr->can_dma)
 901                 return 0;
 902
 903         if (ctlr->dma_tx)
 904                 tx_dev = ctlr->dma_tx->device->dev;
 905         else
 906                 tx_dev = ctlr->dev.parent;
 907
 908         if (ctlr->dma_rx)
 909                 rx_dev = ctlr->dma_rx->device->dev;
 910         else
 911                 rx_dev = ctlr->dev.parent;
 912
 913         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 914                 if (!ctlr->can_dma(ctlr, msg->spi, xfer))
 915                         continue;
 916
 917                 if (xfer->tx_buf != NULL) {
 918                         ret = spi_map_buf(ctlr, tx_dev, &xfer->tx_sg,
 919                                           (void *)xfer->tx_buf, xfer->len,
 920                                           DMA_TO_DEVICE);
 921                         if (ret != 0)
 922                                 return ret;
 923                 }
 924
 925                 if (xfer->rx_buf != NULL) {
 926                         ret = spi_map_buf(ctlr, rx_dev, &xfer->rx_sg,
 927                                           xfer->rx_buf, xfer->len,
 928                                           DMA_FROM_DEVICE);
 929                         if (ret != 0) {
 930                                 spi_unmap_buf(ctlr, tx_dev, &xfer->tx_sg,
 931                                               DMA_TO_DEVICE);
 932                                 return ret;
 933                         }
 934                 }
 935         }
 936
 937         ctlr->cur_msg_mapped = true;
 938
 939         return 0;
 940 }
 941
 942 static int __spi_unmap_msg(struct spi_controller *ctlr, struct spi_message *msg)
 943 {
 944         struct spi_transfer *xfer;
 945         struct device *tx_dev, *rx_dev;
 946
 947         if (!ctlr->cur_msg_mapped || !ctlr->can_dma)
 948                 return 0;
 949
 950         if (ctlr->dma_tx)
 951                 tx_dev = ctlr->dma_tx->device->dev;
 952         else
 953                 tx_dev = ctlr->dev.parent;
 954
 955         if (ctlr->dma_rx)
 956                 rx_dev = ctlr->dma_rx->device->dev;
 957         else
 958                 rx_dev = ctlr->dev.parent;
 959
 960         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 961                 if (!ctlr->can_dma(ctlr, msg->spi, xfer))
 962                         continue;
 963
 964                 spi_unmap_buf(ctlr, rx_dev, &xfer->rx_sg, DMA_FROM_DEVICE);
 965                 spi_unmap_buf(ctlr, tx_dev, &xfer->tx_sg, DMA_TO_DEVICE);
 966         }
 967
 968         return 0;
 969 }
 970 #else /* !CONFIG_HAS_DMA */
 971 static inline int __spi_map_msg(struct spi_controller *ctlr,
 972                                 struct spi_message *msg)
 973 {
 974         return 0;
 975 }
 976
 977 static inline int __spi_unmap_msg(struct spi_controller *ctlr,
 978                                   struct spi_message *msg)
 979 {
 980         return 0;
 981 }
 982 #endif /* !CONFIG_HAS_DMA */
 983
 984 static inline int spi_unmap_msg(struct spi_controller *ctlr,
 985                                 struct spi_message *msg)
 986 {
 987         struct spi_transfer *xfer;
 988
 989         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 990                 /*
 991                  * Restore the original value of tx_buf or rx_buf if they are
 992                  * NULL.
 993                  */
 994                 if (xfer->tx_buf == ctlr->dummy_tx)
 995                         xfer->tx_buf = NULL;
 996                 if (xfer->rx_buf == ctlr->dummy_rx)
 997                         xfer->rx_buf = NULL;
 998         }
 999
1000         return __spi_unmap_msg(ctlr, msg);
1001 }
1002
1003 static int spi_map_msg(struct spi_controller *ctlr, struct spi_message *msg)
1004 {
1005         struct spi_transfer *xfer;
1006         void *tmp;
1007         unsigned int max_tx, max_rx;
1008
1009         if (ctlr->flags & (SPI_CONTROLLER_MUST_RX | SPI_CONTROLLER_MUST_TX)) {
1010                 max_tx = 0;
1011                 max_rx = 0;
1012
1013                 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1014                         if ((ctlr->flags & SPI_CONTROLLER_MUST_TX) &&
1015                             !xfer->tx_buf)
1016                                 max_tx = max(xfer->len, max_tx);
1017                         if ((ctlr->flags & SPI_CONTROLLER_MUST_RX) &&
1018                             !xfer->rx_buf)
1019                                 max_rx = max(xfer->len, max_rx);
1020                 }
1021
1022                 if (max_tx) {
1023                         tmp = krealloc(ctlr->dummy_tx, max_tx,
1024                                        GFP_KERNEL | GFP_DMA);
1025                         if (!tmp)
1026                                 return -ENOMEM;
1027                         ctlr->dummy_tx = tmp;
1028                         memset(tmp, 0, max_tx);
1029                 }
1030
1031                 if (max_rx) {
1032                         tmp = krealloc(ctlr->dummy_rx, max_rx,
1033                                        GFP_KERNEL | GFP_DMA);
1034                         if (!tmp)
1035                                 return -ENOMEM;
1036                         ctlr->dummy_rx = tmp;
1037                 }
1038
1039                 if (max_tx || max_rx) {
1040                         list_for_each_entry(xfer, &msg->transfers,
1041                                             transfer_list) {
1042                                 if (!xfer->tx_buf)
1043                                         xfer->tx_buf = ctlr->dummy_tx;
1044                                 if (!xfer->rx_buf)
1045                                         xfer->rx_buf = ctlr->dummy_rx;
1046                         }
1047                 }
1048         }
1049
1050         return __spi_map_msg(ctlr, msg);
1051 }
1052
1053 static int spi_transfer_wait(struct spi_controller *ctlr,
1054                              struct spi_message *msg,
1055                              struct spi_transfer *xfer)
1056 {
1057         struct spi_statistics *statm = &ctlr->statistics;
1058         struct spi_statistics *stats = &msg->spi->statistics;
1059         unsigned long long ms = 1;
1060
1061         if (spi_controller_is_slave(ctlr)) {
1062                 if (wait_for_completion_interruptible(&ctlr->xfer_completion)) {
1063                         dev_dbg(&msg->spi->dev, "SPI transfer interrupted\n");
1064                         return -EINTR;
1065                 }
1066         } else {
1067                 ms = 8LL * 1000LL * xfer->len;
1068                 do_div(ms, xfer->speed_hz);
1069                 ms += ms + 200; /* some tolerance */
1070
1071                 if (ms > UINT_MAX)
1072                         ms = UINT_MAX;
1073
1074                 ms = wait_for_completion_timeout(&ctlr->xfer_completion,
1075                                                  msecs_to_jiffies(ms));
1076
1077                 if (ms == 0) {
1078                         SPI_STATISTICS_INCREMENT_FIELD(statm, timedout);
1079                         SPI_STATISTICS_INCREMENT_FIELD(stats, timedout);
1080                         dev_err(&msg->spi->dev,
1081                                 "SPI transfer timed out\n");
1082                         return -ETIMEDOUT;
1083                 }
1084         }
1085
1086         return 0;
1087 }
1088
1089 /*
1090  * spi_transfer_one_message - Default implementation of transfer_one_message()
1091  *
1092  * This is a standard implementation of transfer_one_message() for
1093  * drivers which implement a transfer_one() operation.  It provides
1094  * standard handling of delays and chip select management.
1095  */
1096 static int spi_transfer_one_message(struct spi_controller *ctlr,
1097                                     struct spi_message *msg)
1098 {
1099         struct spi_transfer *xfer;
1100         bool keep_cs = false;
1101         int ret = 0;
1102         struct spi_statistics *statm = &ctlr->statistics;
1103         struct spi_statistics *stats = &msg->spi->statistics;
1104
1105         spi_set_cs(msg->spi, true);
1106
1107         SPI_STATISTICS_INCREMENT_FIELD(statm, messages);
1108         SPI_STATISTICS_INCREMENT_FIELD(stats, messages);
1109
1110         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1111                 trace_spi_transfer_start(msg, xfer);
1112
1113                 spi_statistics_add_transfer_stats(statm, xfer, ctlr);
1114                 spi_statistics_add_transfer_stats(stats, xfer, ctlr);
1115
1116                 if (xfer->tx_buf || xfer->rx_buf) {
1117                         reinit_completion(&ctlr->xfer_completion);
1118
1119                         ret = ctlr->transfer_one(ctlr, msg->spi, xfer);
1120                         if (ret < 0) {
1121                                 SPI_STATISTICS_INCREMENT_FIELD(statm,
1122                                                                errors);
1123                                 SPI_STATISTICS_INCREMENT_FIELD(stats,
1124                                                                errors);
1125                                 dev_err(&msg->spi->dev,
1126                                         "SPI transfer failed: %d\n", ret);
1127                                 goto out;
1128                         }
1129
1130                         if (ret > 0) {
1131                                 ret = spi_transfer_wait(ctlr, msg, xfer);
1132                                 if (ret < 0)
1133                                         msg->status = ret;
1134                         }
1135                 } else {
1136                         if (xfer->len)
1137                                 dev_err(&msg->spi->dev,
1138                                         "Bufferless transfer has length %u\n",
1139                                         xfer->len);
1140                 }
1141
1142                 trace_spi_transfer_stop(msg, xfer);
1143
1144                 if (msg->status != -EINPROGRESS)
1145                         goto out;
1146
1147                 if (xfer->delay_usecs) {
1148                         u16 us = xfer->delay_usecs;
1149
1150                         if (us <= 10)
1151                                 udelay(us);
1152                         else
1153                                 usleep_range(us, us + DIV_ROUND_UP(us, 10));
1154                 }
1155
1156                 if (xfer->cs_change) {
1157                         if (list_is_last(&xfer->transfer_list,
1158                                          &msg->transfers)) {
1159                                 keep_cs = true;
1160                         } else {
1161                                 spi_set_cs(msg->spi, false);
1162                                 udelay(10);
1163                                 spi_set_cs(msg->spi, true);
1164                         }
1165                 }
1166
1167                 msg->actual_length += xfer->len;
1168         }
1169
1170 out:
1171         if (ret != 0 || !keep_cs)
1172                 spi_set_cs(msg->spi, false);
1173
1174         if (msg->status == -EINPROGRESS)
1175                 msg->status = ret;
1176
1177         if (msg->status && ctlr->handle_err)
1178                 ctlr->handle_err(ctlr, msg);
1179
1180         spi_res_release(ctlr, msg);
1181
1182         spi_finalize_current_message(ctlr);
1183
1184         return ret;
1185 }
1186
1187 /**
1188  * spi_finalize_current_transfer - report completion of a transfer
1189  * @ctlr: the controller reporting completion
1190  *
1191  * Called by SPI drivers using the core transfer_one_message()
1192  * implementation to notify it that the current interrupt driven
1193  * transfer has finished and the next one may be scheduled.
1194  */
1195 void spi_finalize_current_transfer(struct spi_controller *ctlr)
1196 {
1197         complete(&ctlr->xfer_completion);
1198 }
1199 EXPORT_SYMBOL_GPL(spi_finalize_current_transfer);
1200
1201 /**
1202  * __spi_pump_messages - function which processes spi message queue
1203  * @ctlr: controller to process queue for
1204  * @in_kthread: true if we are in the context of the message pump thread
1205  *
1206  * This function checks if there is any spi message in the queue that
1207  * needs processing and if so call out to the driver to initialize hardware
1208  * and transfer each message.
1209  *
1210  * Note that it is called both from the kthread itself and also from
1211  * inside spi_sync(); the queue extraction handling at the top of the
1212  * function should deal with this safely.
1213  */
1214 static void __spi_pump_messages(struct spi_controller *ctlr, bool in_kthread)
1215 {
1216         unsigned long flags;
1217         bool was_busy = false;
1218         int ret;
1219
1220         /* Lock queue */
1221         spin_lock_irqsave(&ctlr->queue_lock, flags);
1222
1223         /* Make sure we are not already running a message */
1224         if (ctlr->cur_msg) {
1225                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1226                 return;
1227         }
1228
1229         /* If another context is idling the device then defer */
1230         if (ctlr->idling) {
1231                 kthread_queue_work(&ctlr->kworker, &ctlr->pump_messages);
1232                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1233                 return;
1234         }
1235
1236         /* Check if the queue is idle */
1237         if (list_empty(&ctlr->queue) || !ctlr->running) {
1238                 if (!ctlr->busy) {
1239                         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1240                         return;
1241                 }
1242
1243                 /* Only do teardown in the thread */
1244                 if (!in_kthread) {
1245                         kthread_queue_work(&ctlr->kworker,
1246                                            &ctlr->pump_messages);
1247                         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1248                         return;
1249                 }
1250
1251                 ctlr->busy = false;
1252                 ctlr->idling = true;
1253                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1254
1255                 kfree(ctlr->dummy_rx);
1256                 ctlr->dummy_rx = NULL;
1257                 kfree(ctlr->dummy_tx);
1258                 ctlr->dummy_tx = NULL;
1259                 if (ctlr->unprepare_transfer_hardware &&
1260                     ctlr->unprepare_transfer_hardware(ctlr))
1261                         dev_err(&ctlr->dev,
1262                                 "failed to unprepare transfer hardware\n");
1263                 if (ctlr->auto_runtime_pm) {
1264                         pm_runtime_mark_last_busy(ctlr->dev.parent);
1265                         pm_runtime_put_autosuspend(ctlr->dev.parent);
1266                 }
1267                 trace_spi_controller_idle(ctlr);
1268
1269                 spin_lock_irqsave(&ctlr->queue_lock, flags);
1270                 ctlr->idling = false;
1271                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1272                 return;
1273         }
1274
1275         /* Extract head of queue */
1276         ctlr->cur_msg =
1277                 list_first_entry(&ctlr->queue, struct spi_message, queue);
1278
1279         list_del_init(&ctlr->cur_msg->queue);
1280         if (ctlr->busy)
1281                 was_busy = true;
1282         else
1283                 ctlr->busy = true;
1284         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1285
1286         mutex_lock(&ctlr->io_mutex);
1287
1288         if (!was_busy && ctlr->auto_runtime_pm) {
1289                 ret = pm_runtime_get_sync(ctlr->dev.parent);
1290                 if (ret < 0) {
1291                         pm_runtime_put_noidle(ctlr->dev.parent);
1292                         dev_err(&ctlr->dev, "Failed to power device: %d\n",
1293                                 ret);
1294                         mutex_unlock(&ctlr->io_mutex);
1295                         return;
1296                 }
1297         }
1298
1299         if (!was_busy)
1300                 trace_spi_controller_busy(ctlr);
1301
1302         if (!was_busy && ctlr->prepare_transfer_hardware) {
1303                 ret = ctlr->prepare_transfer_hardware(ctlr);
1304                 if (ret) {
1305                         dev_err(&ctlr->dev,
1306                                 "failed to prepare transfer hardware\n");
1307
1308                         if (ctlr->auto_runtime_pm)
1309                                 pm_runtime_put(ctlr->dev.parent);
1310                         mutex_unlock(&ctlr->io_mutex);
1311                         return;
1312                 }
1313         }
1314
1315         trace_spi_message_start(ctlr->cur_msg);
1316
1317         if (ctlr->prepare_message) {
1318                 ret = ctlr->prepare_message(ctlr, ctlr->cur_msg);
1319                 if (ret) {
1320                         dev_err(&ctlr->dev, "failed to prepare message: %d\n",
1321                                 ret);
1322                         ctlr->cur_msg->status = ret;
1323                         spi_finalize_current_message(ctlr);
1324                         goto out;
1325                 }
1326                 ctlr->cur_msg_prepared = true;
1327         }
1328
1329         ret = spi_map_msg(ctlr, ctlr->cur_msg);
1330         if (ret) {
1331                 ctlr->cur_msg->status = ret;
1332                 spi_finalize_current_message(ctlr);
1333                 goto out;
1334         }
1335
1336         ret = ctlr->transfer_one_message(ctlr, ctlr->cur_msg);
1337         if (ret) {
1338                 dev_err(&ctlr->dev,
1339                         "failed to transfer one message from queue\n");
1340                 goto out;
1341         }
1342
1343 out:
1344         mutex_unlock(&ctlr->io_mutex);
1345
1346         /* Prod the scheduler in case transfer_one() was busy waiting */
1347         if (!ret)
1348                 cond_resched();
1349 }
1350
1351 /**
1352  * spi_pump_messages - kthread work function which processes spi message queue
1353  * @work: pointer to kthread work struct contained in the controller struct
1354  */
1355 static void spi_pump_messages(struct kthread_work *work)
1356 {
1357         struct spi_controller *ctlr =
1358                 container_of(work, struct spi_controller, pump_messages);
1359
1360         __spi_pump_messages(ctlr, true);
1361 }
1362
1363 static int spi_init_queue(struct spi_controller *ctlr)
1364 {
1365         struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 };
1366
1367         ctlr->running = false;
1368         ctlr->busy = false;
1369
1370         kthread_init_worker(&ctlr->kworker);
1371         ctlr->kworker_task = kthread_run(kthread_worker_fn, &ctlr->kworker,
1372                                          "%s", dev_name(&ctlr->dev));
1373         if (IS_ERR(ctlr->kworker_task)) {
1374                 dev_err(&ctlr->dev, "failed to create message pump task\n");
1375                 return PTR_ERR(ctlr->kworker_task);
1376         }
1377         kthread_init_work(&ctlr->pump_messages, spi_pump_messages);
1378
1379         /*
1380          * Controller config will indicate if this controller should run the
1381          * message pump with high (realtime) priority to reduce the transfer
1382          * latency on the bus by minimising the delay between a transfer
1383          * request and the scheduling of the message pump thread. Without this
1384          * setting the message pump thread will remain at default priority.
1385          */
1386         if (ctlr->rt) {
1387                 dev_info(&ctlr->dev,
1388                         "will run message pump with realtime priority\n");
1389                 sched_setscheduler(ctlr->kworker_task, SCHED_FIFO, &param);
1390         }
1391
1392         return 0;
1393 }
1394
1395 /**
1396  * spi_get_next_queued_message() - called by driver to check for queued
1397  * messages
1398  * @ctlr: the controller to check for queued messages
1399  *
1400  * If there are more messages in the queue, the next message is returned from
1401  * this call.
1402  *
1403  * Return: the next message in the queue, else NULL if the queue is empty.
1404  */
1405 struct spi_message *spi_get_next_queued_message(struct spi_controller *ctlr)
1406 {
1407         struct spi_message *next;
1408         unsigned long flags;
1409
1410         /* get a pointer to the next message, if any */
1411         spin_lock_irqsave(&ctlr->queue_lock, flags);
1412         next = list_first_entry_or_null(&ctlr->queue, struct spi_message,
1413                                         queue);
1414         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1415
1416         return next;
1417 }
1418 EXPORT_SYMBOL_GPL(spi_get_next_queued_message);
1419
1420 /**
1421  * spi_finalize_current_message() - the current message is complete
1422  * @ctlr: the controller to return the message to
1423  *
1424  * Called by the driver to notify the core that the message in the front of the
1425  * queue is complete and can be removed from the queue.
1426  */
1427 void spi_finalize_current_message(struct spi_controller *ctlr)
1428 {
1429         struct spi_message *mesg;
1430         unsigned long flags;
1431         int ret;
1432
1433         spin_lock_irqsave(&ctlr->queue_lock, flags);
1434         mesg = ctlr->cur_msg;
1435         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1436
1437         spi_unmap_msg(ctlr, mesg);
1438
1439         if (ctlr->cur_msg_prepared && ctlr->unprepare_message) {
1440                 ret = ctlr->unprepare_message(ctlr, mesg);
1441                 if (ret) {
1442                         dev_err(&ctlr->dev, "failed to unprepare message: %d\n",
1443                                 ret);
1444                 }
1445         }
1446
1447         spin_lock_irqsave(&ctlr->queue_lock, flags);
1448         ctlr->cur_msg = NULL;
1449         ctlr->cur_msg_prepared = false;
1450         kthread_queue_work(&ctlr->kworker, &ctlr->pump_messages);
1451         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1452
1453         trace_spi_message_done(mesg);
1454
1455         mesg->state = NULL;
1456         if (mesg->complete)
1457                 mesg->complete(mesg->context);
1458 }
1459 EXPORT_SYMBOL_GPL(spi_finalize_current_message);
1460
1461 static int spi_start_queue(struct spi_controller *ctlr)
1462 {
1463         unsigned long flags;
1464
1465         spin_lock_irqsave(&ctlr->queue_lock, flags);
1466
1467         if (ctlr->running || ctlr->busy) {
1468                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1469                 return -EBUSY;
1470         }
1471
1472         ctlr->running = true;
1473         ctlr->cur_msg = NULL;
1474         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1475
1476         kthread_queue_work(&ctlr->kworker, &ctlr->pump_messages);
1477
1478         return 0;
1479 }
1480
1481 static int spi_stop_queue(struct spi_controller *ctlr)
1482 {
1483         unsigned long flags;
1484         unsigned limit = 500;
1485         int ret = 0;
1486
1487         spin_lock_irqsave(&ctlr->queue_lock, flags);
1488
1489         /*
1490          * This is a bit lame, but is optimized for the common execution path.
1491          * A wait_queue on the ctlr->busy could be used, but then the common
1492          * execution path (pump_messages) would be required to call wake_up or
1493          * friends on every SPI message. Do this instead.
1494          */
1495         while ((!list_empty(&ctlr->queue) || ctlr->busy) && limit--) {
1496                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1497                 usleep_range(10000, 11000);
1498                 spin_lock_irqsave(&ctlr->queue_lock, flags);
1499         }
1500
1501         if (!list_empty(&ctlr->queue) || ctlr->busy)
1502                 ret = -EBUSY;
1503         else
1504                 ctlr->running = false;
1505
1506         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1507
1508         if (ret) {
1509                 dev_warn(&ctlr->dev, "could not stop message queue\n");
1510                 return ret;
1511         }
1512         return ret;
1513 }
1514
1515 static int spi_destroy_queue(struct spi_controller *ctlr)
1516 {
1517         int ret;
1518
1519         ret = spi_stop_queue(ctlr);
1520
1521         /*
1522          * kthread_flush_worker will block until all work is done.
1523          * If the reason that stop_queue timed out is that the work will never
1524          * finish, then it does no good to call flush/stop thread, so
1525          * return anyway.
1526          */
1527         if (ret) {
1528                 dev_err(&ctlr->dev, "problem destroying queue\n");
1529                 return ret;
1530         }
1531
1532         kthread_flush_worker(&ctlr->kworker);
1533         kthread_stop(ctlr->kworker_task);
1534
1535         return 0;
1536 }
1537
1538 static int __spi_queued_transfer(struct spi_device *spi,
1539                                  struct spi_message *msg,
1540                                  bool need_pump)
1541 {
1542         struct spi_controller *ctlr = spi->controller;
1543         unsigned long flags;
1544
1545         spin_lock_irqsave(&ctlr->queue_lock, flags);
1546
1547         if (!ctlr->running) {
1548                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1549                 return -ESHUTDOWN;
1550         }
1551         msg->actual_length = 0;
1552         msg->status = -EINPROGRESS;
1553
1554         list_add_tail(&msg->queue, &ctlr->queue);
1555         if (!ctlr->busy && need_pump)
1556                 kthread_queue_work(&ctlr->kworker, &ctlr->pump_messages);
1557
1558         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1559         return 0;
1560 }
1561
1562 /**
1563  * spi_queued_transfer - transfer function for queued transfers
1564  * @spi: spi device which is requesting transfer
1565  * @msg: spi message which is to handled is queued to driver queue
1566  *
1567  * Return: zero on success, else a negative error code.
1568  */
1569 static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
1570 {
1571         return __spi_queued_transfer(spi, msg, true);
1572 }
1573
1574 static int spi_controller_initialize_queue(struct spi_controller *ctlr)
1575 {
1576         int ret;
1577
1578         ctlr->transfer = spi_queued_transfer;
1579         if (!ctlr->transfer_one_message)
1580                 ctlr->transfer_one_message = spi_transfer_one_message;
1581
1582         /* Initialize and start queue */
1583         ret = spi_init_queue(ctlr);
1584         if (ret) {
1585                 dev_err(&ctlr->dev, "problem initializing queue\n");
1586                 goto err_init_queue;
1587         }
1588         ctlr->queued = true;
1589         ret = spi_start_queue(ctlr);
1590         if (ret) {
1591                 dev_err(&ctlr->dev, "problem starting queue\n");
1592                 goto err_start_queue;
1593         }
1594
1595         return 0;
1596
1597 err_start_queue:
1598         spi_destroy_queue(ctlr);
1599 err_init_queue:
1600         return ret;
1601 }
1602
1603 /**
1604  * spi_flush_queue - Send all pending messages in the queue from the callers'
1605  *                   context
1606  * @ctlr: controller to process queue for
1607  *
1608  * This should be used when one wants to ensure all pending messages have been
1609  * sent before doing something. Is used by the spi-mem code to make sure SPI
1610  * memory operations do not preempt regular SPI transfers that have been queued
1611  * before the spi-mem operation.
1612  */
1613 void spi_flush_queue(struct spi_controller *ctlr)
1614 {
1615         if (ctlr->transfer == spi_queued_transfer)
1616                 __spi_pump_messages(ctlr, false);
1617 }
1618
1619 /*-------------------------------------------------------------------------*/
1620
1621 #if defined(CONFIG_OF)
1622 static int of_spi_parse_dt(struct spi_controller *ctlr, struct spi_device *spi,
1623                            struct device_node *nc)
1624 {
1625         u32 value;
1626         int rc;
1627
1628         /* Mode (clock phase/polarity/etc.) */
1629         if (of_property_read_bool(nc, "spi-cpha"))
1630                 spi->mode |= SPI_CPHA;
1631         if (of_property_read_bool(nc, "spi-cpol"))
1632                 spi->mode |= SPI_CPOL;
1633         if (of_property_read_bool(nc, "spi-3wire"))
1634                 spi->mode |= SPI_3WIRE;
1635         if (of_property_read_bool(nc, "spi-lsb-first"))
1636                 spi->mode |= SPI_LSB_FIRST;
1637
1638         /*
1639          * For descriptors associated with the device, polarity inversion is
1640          * handled in the gpiolib, so all chip selects are "active high" in
1641          * the logical sense, the gpiolib will invert the line if need be.
1642          */
1643         if (ctlr->use_gpio_descriptors)
1644                 spi->mode |= SPI_CS_HIGH;
1645         else if (of_property_read_bool(nc, "spi-cs-high"))
1646                 spi->mode |= SPI_CS_HIGH;
1647
1648         /* Device DUAL/QUAD mode */
1649         if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) {
1650                 switch (value) {
1651                 case 1:
1652                         break;
1653                 case 2:
1654                         spi->mode |= SPI_TX_DUAL;
1655                         break;
1656                 case 4:
1657                         spi->mode |= SPI_TX_QUAD;
1658                         break;
1659                 case 8:
1660                         spi->mode |= SPI_TX_OCTAL;
1661                         break;
1662                 default:
1663                         dev_warn(&ctlr->dev,
1664                                 "spi-tx-bus-width %d not supported\n",
1665                                 value);
1666                         break;
1667                 }
1668         }
1669
1670         if (!of_property_read_u32(nc, "spi-rx-bus-width", &value)) {
1671                 switch (value) {
1672                 case 1:
1673                         break;
1674                 case 2:
1675                         spi->mode |= SPI_RX_DUAL;
1676                         break;
1677                 case 4:
1678                         spi->mode |= SPI_RX_QUAD;
1679                         break;
1680                 case 8:
1681                         spi->mode |= SPI_RX_OCTAL;
1682                         break;
1683                 default:
1684                         dev_warn(&ctlr->dev,
1685                                 "spi-rx-bus-width %d not supported\n",
1686                                 value);
1687                         break;
1688                 }
1689         }
1690
1691         if (spi_controller_is_slave(ctlr)) {
1692                 if (!of_node_name_eq(nc, "slave")) {
1693                         dev_err(&ctlr->dev, "%pOF is not called 'slave'\n",
1694                                 nc);
1695                         return -EINVAL;
1696                 }
1697                 return 0;
1698         }
1699
1700         /* Device address */
1701         rc = of_property_read_u32(nc, "reg", &value);
1702         if (rc) {
1703                 dev_err(&ctlr->dev, "%pOF has no valid 'reg' property (%d)\n",
1704                         nc, rc);
1705                 return rc;
1706         }
1707         spi->chip_select = value;
1708
1709         /* Device speed */
1710         rc = of_property_read_u32(nc, "spi-max-frequency", &value);
1711         if (rc) {
1712                 dev_err(&ctlr->dev,
1713                         "%pOF has no valid 'spi-max-frequency' property (%d)\n", nc, rc);
1714                 return rc;
1715         }
1716         spi->max_speed_hz = value;
1717
1718         return 0;
1719 }
1720
1721 static struct spi_device *
1722 of_register_spi_device(struct spi_controller *ctlr, struct device_node *nc)
1723 {
1724         struct spi_device *spi;
1725         int rc;
1726
1727         /* Alloc an spi_device */
1728         spi = spi_alloc_device(ctlr);
1729         if (!spi) {
1730                 dev_err(&ctlr->dev, "spi_device alloc error for %pOF\n", nc);
1731                 rc = -ENOMEM;
1732                 goto err_out;
1733         }
1734
1735         /* Select device driver */
1736         rc = of_modalias_node(nc, spi->modalias,
1737                                 sizeof(spi->modalias));
1738         if (rc < 0) {
1739                 dev_err(&ctlr->dev, "cannot find modalias for %pOF\n", nc);
1740                 goto err_out;
1741         }
1742
1743         rc = of_spi_parse_dt(ctlr, spi, nc);
1744         if (rc)
1745                 goto err_out;
1746
1747         /* Store a pointer to the node in the device structure */
1748         of_node_get(nc);
1749         spi->dev.of_node = nc;
1750
1751         /* Register the new device */
1752         rc = spi_add_device(spi);
1753         if (rc) {
1754                 dev_err(&ctlr->dev, "spi_device register error %pOF\n", nc);
1755                 goto err_of_node_put;
1756         }
1757
1758         return spi;
1759
1760 err_of_node_put:
1761         of_node_put(nc);
1762 err_out:
1763         spi_dev_put(spi);
1764         return ERR_PTR(rc);
1765 }
1766
1767 /**
1768  * of_register_spi_devices() - Register child devices onto the SPI bus
1769  * @ctlr:       Pointer to spi_controller device
1770  *
1771  * Registers an spi_device for each child node of controller node which
1772  * represents a valid SPI slave.
1773  */
1774 static void of_register_spi_devices(struct spi_controller *ctlr)
1775 {
1776         struct spi_device *spi;
1777         struct device_node *nc;
1778
1779         if (!ctlr->dev.of_node)
1780                 return;
1781
1782         for_each_available_child_of_node(ctlr->dev.of_node, nc) {
1783                 if (of_node_test_and_set_flag(nc, OF_POPULATED))
1784                         continue;
1785                 spi = of_register_spi_device(ctlr, nc);
1786                 if (IS_ERR(spi)) {
1787                         dev_warn(&ctlr->dev,
1788                                  "Failed to create SPI device for %pOF\n", nc);
1789                         of_node_clear_flag(nc, OF_POPULATED);
1790                 }
1791         }
1792 }
1793 #else
1794 static void of_register_spi_devices(struct spi_controller *ctlr) { }
1795 #endif
1796
1797 #ifdef CONFIG_ACPI
1798 static void acpi_spi_parse_apple_properties(struct spi_device *spi)
1799 {
1800         struct acpi_device *dev = ACPI_COMPANION(&spi->dev);
1801         const union acpi_object *obj;
1802
1803         if (!x86_apple_machine)
1804                 return;
1805
1806         if (!acpi_dev_get_property(dev, "spiSclkPeriod", ACPI_TYPE_BUFFER, &obj)
1807             && obj->buffer.length >= 4)
1808                 spi->max_speed_hz  = NSEC_PER_SEC / *(u32 *)obj->buffer.pointer;
1809
1810         if (!acpi_dev_get_property(dev, "spiWordSize", ACPI_TYPE_BUFFER, &obj)
1811             && obj->buffer.length == 8)
1812                 spi->bits_per_word = *(u64 *)obj->buffer.pointer;
1813
1814         if (!acpi_dev_get_property(dev, "spiBitOrder", ACPI_TYPE_BUFFER, &obj)
1815             && obj->buffer.length == 8 && !*(u64 *)obj->buffer.pointer)
1816                 spi->mode |= SPI_LSB_FIRST;
1817
1818         if (!acpi_dev_get_property(dev, "spiSPO", ACPI_TYPE_BUFFER, &obj)
1819             && obj->buffer.length == 8 &&  *(u64 *)obj->buffer.pointer)
1820                 spi->mode |= SPI_CPOL;
1821
1822         if (!acpi_dev_get_property(dev, "spiSPH", ACPI_TYPE_BUFFER, &obj)
1823             && obj->buffer.length == 8 &&  *(u64 *)obj->buffer.pointer)
1824                 spi->mode |= SPI_CPHA;
1825 }
1826
1827 static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
1828 {
1829         struct spi_device *spi = data;
1830         struct spi_controller *ctlr = spi->controller;
1831
1832         if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
1833                 struct acpi_resource_spi_serialbus *sb;
1834
1835                 sb = &ares->data.spi_serial_bus;
1836                 if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) {
1837                         /*
1838                          * ACPI DeviceSelection numbering is handled by the
1839                          * host controller driver in Windows and can vary
1840                          * from driver to driver. In Linux we always expect
1841                          * 0 .. max - 1 so we need to ask the driver to
1842                          * translate between the two schemes.
1843                          */
1844                         if (ctlr->fw_translate_cs) {
1845                                 int cs = ctlr->fw_translate_cs(ctlr,
1846                                                 sb->device_selection);
1847                                 if (cs < 0)
1848                                         return cs;
1849                                 spi->chip_select = cs;
1850                         } else {
1851                                 spi->chip_select = sb->device_selection;
1852                         }
1853
1854                         spi->max_speed_hz = sb->connection_speed;
1855
1856                         if (sb->clock_phase == ACPI_SPI_SECOND_PHASE)
1857                                 spi->mode |= SPI_CPHA;
1858                         if (sb->clock_polarity == ACPI_SPI_START_HIGH)
1859                                 spi->mode |= SPI_CPOL;
1860                         if (sb->device_polarity == ACPI_SPI_ACTIVE_HIGH)
1861                                 spi->mode |= SPI_CS_HIGH;
1862                 }
1863         } else if (spi->irq < 0) {
1864                 struct resource r;
1865
1866                 if (acpi_dev_resource_interrupt(ares, 0, &r))
1867                         spi->irq = r.start;
1868         }
1869
1870         /* Always tell the ACPI core to skip this resource */
1871         return 1;
1872 }
1873
1874 static acpi_status acpi_register_spi_device(struct spi_controller *ctlr,
1875                                             struct acpi_device *adev)
1876 {
1877         struct list_head resource_list;
1878         struct spi_device *spi;
1879         int ret;
1880
1881         if (acpi_bus_get_status(adev) || !adev->status.present ||
1882             acpi_device_enumerated(adev))
1883                 return AE_OK;
1884
1885         spi = spi_alloc_device(ctlr);
1886         if (!spi) {
1887                 dev_err(&ctlr->dev, "failed to allocate SPI device for %s\n",
1888                         dev_name(&adev->dev));
1889                 return AE_NO_MEMORY;
1890         }
1891
1892         ACPI_COMPANION_SET(&spi->dev, adev);
1893         spi->irq = -1;
1894
1895         INIT_LIST_HEAD(&resource_list);
1896         ret = acpi_dev_get_resources(adev, &resource_list,
1897                                      acpi_spi_add_resource, spi);
1898         acpi_dev_free_resource_list(&resource_list);
1899
1900         acpi_spi_parse_apple_properties(spi);
1901
1902         if (ret < 0 || !spi->max_speed_hz) {
1903                 spi_dev_put(spi);
1904                 return AE_OK;
1905         }
1906
1907         acpi_set_modalias(adev, acpi_device_hid(adev), spi->modalias,
1908                           sizeof(spi->modalias));
1909
1910         if (spi->irq < 0)
1911                 spi->irq = acpi_dev_gpio_irq_get(adev, 0);
1912
1913         acpi_device_set_enumerated(adev);
1914
1915         adev->power.flags.ignore_parent = true;
1916         if (spi_add_device(spi)) {
1917                 adev->power.flags.ignore_parent = false;
1918                 dev_err(&ctlr->dev, "failed to add SPI device %s from ACPI\n",
1919                         dev_name(&adev->dev));
1920                 spi_dev_put(spi);
1921         }
1922
1923         return AE_OK;
1924 }
1925
1926 static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level,
1927                                        void *data, void **return_value)
1928 {
1929         struct spi_controller *ctlr = data;
1930         struct acpi_device *adev;
1931
1932         if (acpi_bus_get_device(handle, &adev))
1933                 return AE_OK;
1934
1935         return acpi_register_spi_device(ctlr, adev);
1936 }
1937
1938 static void acpi_register_spi_devices(struct spi_controller *ctlr)
1939 {
1940         acpi_status status;
1941         acpi_handle handle;
1942
1943         handle = ACPI_HANDLE(ctlr->dev.parent);
1944         if (!handle)
1945                 return;
1946
1947         status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
1948                                      acpi_spi_add_device, NULL, ctlr, NULL);
1949         if (ACPI_FAILURE(status))
1950                 dev_warn(&ctlr->dev, "failed to enumerate SPI slaves\n");
1951 }
1952 #else
1953 static inline void acpi_register_spi_devices(struct spi_controller *ctlr) {}
1954 #endif /* CONFIG_ACPI */
1955
1956 static void spi_controller_release(struct device *dev)
1957 {
1958         struct spi_controller *ctlr;
1959
1960         ctlr = container_of(dev, struct spi_controller, dev);
1961         kfree(ctlr);
1962 }
1963
1964 static struct class spi_master_class = {
1965         .name           = "spi_master",
1966         .owner          = THIS_MODULE,
1967         .dev_release    = spi_controller_release,
1968         .dev_groups     = spi_master_groups,
1969 };
1970
1971 #ifdef CONFIG_SPI_SLAVE
1972 /**
1973  * spi_slave_abort - abort the ongoing transfer request on an SPI slave
1974  *                   controller
1975  * @spi: device used for the current transfer
1976  */
1977 int spi_slave_abort(struct spi_device *spi)
1978 {
1979         struct spi_controller *ctlr = spi->controller;
1980
1981         if (spi_controller_is_slave(ctlr) && ctlr->slave_abort)
1982                 return ctlr->slave_abort(ctlr);
1983
1984         return -ENOTSUPP;
1985 }
1986 EXPORT_SYMBOL_GPL(spi_slave_abort);
1987
1988 static int match_true(struct device *dev, void *data)
1989 {
1990         return 1;
1991 }
1992
1993 static ssize_t spi_slave_show(struct device *dev,
1994                               struct device_attribute *attr, char *buf)
1995 {
1996         struct spi_controller *ctlr = container_of(dev, struct spi_controller,
1997                                                    dev);
1998         struct device *child;
1999
2000         child = device_find_child(&ctlr->dev, NULL, match_true);
2001         return sprintf(buf, "%s\n",
2002                        child ? to_spi_device(child)->modalias : NULL);
2003 }
2004
2005 static ssize_t spi_slave_store(struct device *dev,
2006                                struct device_attribute *attr, const char *buf,
2007                                size_t count)
2008 {
2009         struct spi_controller *ctlr = container_of(dev, struct spi_controller,
2010                                                    dev);
2011         struct spi_device *spi;
2012         struct device *child;
2013         char name[32];
2014         int rc;
2015
2016         rc = sscanf(buf, "%31s", name);
2017         if (rc != 1 || !name[0])
2018                 return -EINVAL;
2019
2020         child = device_find_child(&ctlr->dev, NULL, match_true);
2021         if (child) {
2022                 /* Remove registered slave */
2023                 device_unregister(child);
2024                 put_device(child);
2025         }
2026
2027         if (strcmp(name, "(null)")) {
2028                 /* Register new slave */
2029                 spi = spi_alloc_device(ctlr);
2030                 if (!spi)
2031                         return -ENOMEM;
2032
2033                 strlcpy(spi->modalias, name, sizeof(spi->modalias));
2034
2035                 rc = spi_add_device(spi);
2036                 if (rc) {
2037                         spi_dev_put(spi);
2038                         return rc;
2039                 }
2040         }
2041
2042         return count;
2043 }
2044
2045 static DEVICE_ATTR(slave, 0644, spi_slave_show, spi_slave_store);
2046
2047 static struct attribute *spi_slave_attrs[] = {
2048         &dev_attr_slave.attr,
2049         NULL,
2050 };
2051
2052 static const struct attribute_group spi_slave_group = {
2053         .attrs = spi_slave_attrs,
2054 };
2055
2056 static const struct attribute_group *spi_slave_groups[] = {
2057         &spi_controller_statistics_group,
2058         &spi_slave_group,
2059         NULL,
2060 };
2061
2062 static struct class spi_slave_class = {
2063         .name           = "spi_slave",
2064         .owner          = THIS_MODULE,
2065         .dev_release    = spi_controller_release,
2066         .dev_groups     = spi_slave_groups,
2067 };
2068 #else
2069 extern struct class spi_slave_class;    /* dummy */
2070 #endif
2071
2072 /**
2073  * __spi_alloc_controller - allocate an SPI master or slave controller
2074  * @dev: the controller, possibly using the platform_bus
2075  * @size: how much zeroed driver-private data to allocate; the pointer to this
2076  *      memory is in the driver_data field of the returned device,
2077  *      accessible with spi_controller_get_devdata().
2078  * @slave: flag indicating whether to allocate an SPI master (false) or SPI
2079  *      slave (true) controller
2080  * Context: can sleep
2081  *
2082  * This call is used only by SPI controller drivers, which are the
2083  * only ones directly touching chip registers.  It's how they allocate
2084  * an spi_controller structure, prior to calling spi_register_controller().
2085  *
2086  * This must be called from context that can sleep.
2087  *
2088  * The caller is responsible for assigning the bus number and initializing the
2089  * controller's methods before calling spi_register_controller(); and (after
2090  * errors adding the device) calling spi_controller_put() to prevent a memory
2091  * leak.
2092  *
2093  * Return: the SPI controller structure on success, else NULL.
2094  */
2095 struct spi_controller *__spi_alloc_controller(struct device *dev,
2096                                               unsigned int size, bool slave)
2097 {
2098         struct spi_controller   *ctlr;
2099
2100         if (!dev)
2101                 return NULL;
2102
2103         ctlr = kzalloc(size + sizeof(*ctlr), GFP_KERNEL);
2104         if (!ctlr)
2105                 return NULL;
2106
2107         device_initialize(&ctlr->dev);
2108         ctlr->bus_num = -1;
2109         ctlr->num_chipselect = 1;
2110         ctlr->slave = slave;
2111         if (IS_ENABLED(CONFIG_SPI_SLAVE) && slave)
2112                 ctlr->dev.class = &spi_slave_class;
2113         else
2114                 ctlr->dev.class = &spi_master_class;
2115         ctlr->dev.parent = dev;
2116         pm_suspend_ignore_children(&ctlr->dev, true);
2117         spi_controller_set_devdata(ctlr, &ctlr[1]);
2118
2119         return ctlr;
2120 }
2121 EXPORT_SYMBOL_GPL(__spi_alloc_controller);
2122
2123 #ifdef CONFIG_OF
2124 static int of_spi_register_master(struct spi_controller *ctlr)
2125 {
2126         int nb, i, *cs;
2127         struct device_node *np = ctlr->dev.of_node;
2128
2129         if (!np)
2130                 return 0;
2131
2132         nb = of_gpio_named_count(np, "cs-gpios");
2133         ctlr->num_chipselect = max_t(int, nb, ctlr->num_chipselect);
2134
2135         /* Return error only for an incorrectly formed cs-gpios property */
2136         if (nb == 0 || nb == -ENOENT)
2137                 return 0;
2138         else if (nb < 0)
2139                 return nb;
2140
2141         cs = devm_kcalloc(&ctlr->dev, ctlr->num_chipselect, sizeof(int),
2142                           GFP_KERNEL);
2143         ctlr->cs_gpios = cs;
2144
2145         if (!ctlr->cs_gpios)
2146                 return -ENOMEM;
2147
2148         for (i = 0; i < ctlr->num_chipselect; i++)
2149                 cs[i] = -ENOENT;
2150
2151         for (i = 0; i < nb; i++)
2152                 cs[i] = of_get_named_gpio(np, "cs-gpios", i);
2153
2154         return 0;
2155 }
2156 #else
2157 static int of_spi_register_master(struct spi_controller *ctlr)
2158 {
2159         return 0;
2160 }
2161 #endif
2162
2163 /**
2164  * spi_get_gpio_descs() - grab chip select GPIOs for the master
2165  * @ctlr: The SPI master to grab GPIO descriptors for
2166  */
2167 static int spi_get_gpio_descs(struct spi_controller *ctlr)
2168 {
2169         int nb, i;
2170         struct gpio_desc **cs;
2171         struct device *dev = &ctlr->dev;
2172
2173         nb = gpiod_count(dev, "cs");
2174         ctlr->num_chipselect = max_t(int, nb, ctlr->num_chipselect);
2175
2176         /* No GPIOs at all is fine, else return the error */
2177         if (nb == 0 || nb == -ENOENT)
2178                 return 0;
2179         else if (nb < 0)
2180                 return nb;
2181
2182         cs = devm_kcalloc(dev, ctlr->num_chipselect, sizeof(*cs),
2183                           GFP_KERNEL);
2184         if (!cs)
2185                 return -ENOMEM;
2186         ctlr->cs_gpiods = cs;
2187
2188         for (i = 0; i < nb; i++) {
2189                 /*
2190                  * Most chipselects are active low, the inverted
2191                  * semantics are handled by special quirks in gpiolib,
2192                  * so initializing them GPIOD_OUT_LOW here means
2193                  * "unasserted", in most cases this will drive the physical
2194                  * line high.
2195                  */
2196                 cs[i] = devm_gpiod_get_index_optional(dev, "cs", i,
2197                                                       GPIOD_OUT_LOW);
2198
2199                 if (cs[i]) {
2200                         /*
2201                          * If we find a CS GPIO, name it after the device and
2202                          * chip select line.
2203                          */
2204                         char *gpioname;
2205
2206                         gpioname = devm_kasprintf(dev, GFP_KERNEL, "%s CS%d",
2207                                                   dev_name(dev), i);
2208                         if (!gpioname)
2209                                 return -ENOMEM;
2210                         gpiod_set_consumer_name(cs[i], gpioname);
2211                 }
2212         }
2213
2214         return 0;
2215 }
2216
2217 static int spi_controller_check_ops(struct spi_controller *ctlr)
2218 {
2219         /*
2220          * The controller may implement only the high-level SPI-memory like
2221          * operations if it does not support regular SPI transfers, and this is
2222          * valid use case.
2223          * If ->mem_ops is NULL, we request that at least one of the
2224          * ->transfer_xxx() method be implemented.
2225          */
2226         if (ctlr->mem_ops) {
2227                 if (!ctlr->mem_ops->exec_op)
2228                         return -EINVAL;
2229         } else if (!ctlr->transfer && !ctlr->transfer_one &&
2230                    !ctlr->transfer_one_message) {
2231                 return -EINVAL;
2232         }
2233
2234         return 0;
2235 }
2236
2237 /**
2238  * spi_register_controller - register SPI master or slave controller
2239  * @ctlr: initialized master, originally from spi_alloc_master() or
2240  *      spi_alloc_slave()
2241  * Context: can sleep
2242  *
2243  * SPI controllers connect to their drivers using some non-SPI bus,
2244  * such as the platform bus.  The final stage of probe() in that code
2245  * includes calling spi_register_controller() to hook up to this SPI bus glue.
2246  *
2247  * SPI controllers use board specific (often SOC specific) bus numbers,
2248  * and board-specific addressing for SPI devices combines those numbers
2249  * with chip select numbers.  Since SPI does not directly support dynamic
2250  * device identification, boards need configuration tables telling which
2251  * chip is at which address.
2252  *
2253  * This must be called from context that can sleep.  It returns zero on
2254  * success, else a negative error code (dropping the controller's refcount).
2255  * After a successful return, the caller is responsible for calling
2256  * spi_unregister_controller().
2257  *
2258  * Return: zero on success, else a negative error code.
2259  */
2260 int spi_register_controller(struct spi_controller *ctlr)
2261 {
2262         struct device           *dev = ctlr->dev.parent;
2263         struct boardinfo        *bi;
2264         int                     status = -ENODEV;
2265         int                     id, first_dynamic;
2266
2267         if (!dev)
2268                 return -ENODEV;
2269
2270         /*
2271          * Make sure all necessary hooks are implemented before registering
2272          * the SPI controller.
2273          */
2274         status = spi_controller_check_ops(ctlr);
2275         if (status)
2276                 return status;
2277
2278         if (!spi_controller_is_slave(ctlr)) {
2279                 if (ctlr->use_gpio_descriptors) {
2280                         status = spi_get_gpio_descs(ctlr);
2281                         if (status)
2282                                 return status;
2283                         /*
2284                          * A controller using GPIO descriptors always
2285                          * supports SPI_CS_HIGH if need be.
2286                          */
2287                         ctlr->mode_bits |= SPI_CS_HIGH;
2288                 } else {
2289                         /* Legacy code path for GPIOs from DT */
2290                         status = of_spi_register_master(ctlr);
2291                         if (status)
2292                                 return status;
2293                 }
2294         }
2295
2296         /* even if it's just one always-selected device, there must
2297          * be at least one chipselect
2298          */
2299         if (ctlr->num_chipselect == 0)
2300                 return -EINVAL;
2301         if (ctlr->bus_num >= 0) {
2302                 /* devices with a fixed bus num must check-in with the num */
2303                 mutex_lock(&board_lock);
2304                 id = idr_alloc(&spi_master_idr, ctlr, ctlr->bus_num,
2305                         ctlr->bus_num + 1, GFP_KERNEL);
2306                 mutex_unlock(&board_lock);
2307                 if (WARN(id < 0, "couldn't get idr"))
2308                         return id == -ENOSPC ? -EBUSY : id;
2309                 ctlr->bus_num = id;
2310         } else if (ctlr->dev.of_node) {
2311                 /* allocate dynamic bus number using Linux idr */
2312                 id = of_alias_get_id(ctlr->dev.of_node, "spi");
2313                 if (id >= 0) {
2314                         ctlr->bus_num = id;
2315                         mutex_lock(&board_lock);
2316                         id = idr_alloc(&spi_master_idr, ctlr, ctlr->bus_num,
2317                                        ctlr->bus_num + 1, GFP_KERNEL);
2318                         mutex_unlock(&board_lock);
2319                         if (WARN(id < 0, "couldn't get idr"))
2320                                 return id == -ENOSPC ? -EBUSY : id;
2321                 }
2322         }
2323         if (ctlr->bus_num < 0) {
2324                 first_dynamic = of_alias_get_highest_id("spi");
2325                 if (first_dynamic < 0)
2326                         first_dynamic = 0;
2327                 else
2328                         first_dynamic++;
2329
2330                 mutex_lock(&board_lock);
2331                 id = idr_alloc(&spi_master_idr, ctlr, first_dynamic,
2332                                0, GFP_KERNEL);
2333                 mutex_unlock(&board_lock);
2334                 if (WARN(id < 0, "couldn't get idr"))
2335                         return id;
2336                 ctlr->bus_num = id;
2337         }
2338         INIT_LIST_HEAD(&ctlr->queue);
2339         spin_lock_init(&ctlr->queue_lock);
2340         spin_lock_init(&ctlr->bus_lock_spinlock);
2341         mutex_init(&ctlr->bus_lock_mutex);
2342         mutex_init(&ctlr->io_mutex);
2343         ctlr->bus_lock_flag = 0;
2344         init_completion(&ctlr->xfer_completion);
2345         if (!ctlr->max_dma_len)
2346                 ctlr->max_dma_len = INT_MAX;
2347
2348         /* register the device, then userspace will see it.
2349          * registration fails if the bus ID is in use.
2350          */
2351         dev_set_name(&ctlr->dev, "spi%u", ctlr->bus_num);
2352         status = device_add(&ctlr->dev);
2353         if (status < 0) {
2354                 /* free bus id */
2355                 mutex_lock(&board_lock);
2356                 idr_remove(&spi_master_idr, ctlr->bus_num);
2357                 mutex_unlock(&board_lock);
2358                 goto done;
2359         }
2360         dev_dbg(dev, "registered %s %s\n",
2361                         spi_controller_is_slave(ctlr) ? "slave" : "master",
2362                         dev_name(&ctlr->dev));
2363
2364         /*
2365          * If we're using a queued driver, start the queue. Note that we don't
2366          * need the queueing logic if the driver is only supporting high-level
2367          * memory operations.
2368          */
2369         if (ctlr->transfer) {
2370                 dev_info(dev, "controller is unqueued, this is deprecated\n");
2371         } else if (ctlr->transfer_one || ctlr->transfer_one_message) {
2372                 status = spi_controller_initialize_queue(ctlr);
2373                 if (status) {
2374                         device_del(&ctlr->dev);
2375                         /* free bus id */
2376                         mutex_lock(&board_lock);
2377                         idr_remove(&spi_master_idr, ctlr->bus_num);
2378                         mutex_unlock(&board_lock);
2379                         goto done;
2380                 }
2381         }
2382         /* add statistics */
2383         spin_lock_init(&ctlr->statistics.lock);
2384
2385         mutex_lock(&board_lock);
2386         list_add_tail(&ctlr->list, &spi_controller_list);
2387         list_for_each_entry(bi, &board_list, list)
2388                 spi_match_controller_to_boardinfo(ctlr, &bi->board_info);
2389         mutex_unlock(&board_lock);
2390
2391         /* Register devices from the device tree and ACPI */
2392         of_register_spi_devices(ctlr);
2393         acpi_register_spi_devices(ctlr);
2394 done:
2395         return status;
2396 }
2397 EXPORT_SYMBOL_GPL(spi_register_controller);
2398
2399 static void devm_spi_unregister(struct device *dev, void *res)
2400 {
2401         spi_unregister_controller(*(struct spi_controller **)res);
2402 }
2403
2404 /**
2405  * devm_spi_register_controller - register managed SPI master or slave
2406  *      controller
2407  * @dev:    device managing SPI controller
2408  * @ctlr: initialized controller, originally from spi_alloc_master() or
2409  *      spi_alloc_slave()
2410  * Context: can sleep
2411  *
2412  * Register a SPI device as with spi_register_controller() which will
2413  * automatically be unregistered and freed.
2414  *
2415  * Return: zero on success, else a negative error code.
2416  */
2417 int devm_spi_register_controller(struct device *dev,
2418                                  struct spi_controller *ctlr)
2419 {
2420         struct spi_controller **ptr;
2421         int ret;
2422
2423         ptr = devres_alloc(devm_spi_unregister, sizeof(*ptr), GFP_KERNEL);
2424         if (!ptr)
2425                 return -ENOMEM;
2426
2427         ret = spi_register_controller(ctlr);
2428         if (!ret) {
2429                 *ptr = ctlr;
2430                 devres_add(dev, ptr);
2431         } else {
2432                 devres_free(ptr);
2433         }
2434
2435         return ret;
2436 }
2437 EXPORT_SYMBOL_GPL(devm_spi_register_controller);
2438
2439 static int __unregister(struct device *dev, void *null)
2440 {
2441         spi_unregister_device(to_spi_device(dev));
2442         return 0;
2443 }
2444
2445 /**
2446  * spi_unregister_controller - unregister SPI master or slave controller
2447  * @ctlr: the controller being unregistered
2448  * Context: can sleep
2449  *
2450  * This call is used only by SPI controller drivers, which are the
2451  * only ones directly touching chip registers.
2452  *
2453  * This must be called from context that can sleep.
2454  *
2455  * Note that this function also drops a reference to the controller.
2456  */
2457 void spi_unregister_controller(struct spi_controller *ctlr)
2458 {
2459         struct spi_controller *found;
2460         int id = ctlr->bus_num;
2461         int dummy;
2462
2463         /* First make sure that this controller was ever added */
2464         mutex_lock(&board_lock);
2465         found = idr_find(&spi_master_idr, id);
2466         mutex_unlock(&board_lock);
2467         if (ctlr->queued) {
2468                 if (spi_destroy_queue(ctlr))
2469                         dev_err(&ctlr->dev, "queue remove failed\n");
2470         }
2471         mutex_lock(&board_lock);
2472         list_del(&ctlr->list);
2473         mutex_unlock(&board_lock);
2474
2475         dummy = device_for_each_child(&ctlr->dev, NULL, __unregister);
2476         device_unregister(&ctlr->dev);
2477         /* free bus id */
2478         mutex_lock(&board_lock);
2479         if (found == ctlr)
2480                 idr_remove(&spi_master_idr, id);
2481         mutex_unlock(&board_lock);
2482 }
2483 EXPORT_SYMBOL_GPL(spi_unregister_controller);
2484
2485 int spi_controller_suspend(struct spi_controller *ctlr)
2486 {
2487         int ret;
2488
2489         /* Basically no-ops for non-queued controllers */
2490         if (!ctlr->queued)
2491                 return 0;
2492
2493         ret = spi_stop_queue(ctlr);
2494         if (ret)
2495                 dev_err(&ctlr->dev, "queue stop failed\n");
2496
2497         return ret;
2498 }
2499 EXPORT_SYMBOL_GPL(spi_controller_suspend);
2500
2501 int spi_controller_resume(struct spi_controller *ctlr)
2502 {
2503         int ret;
2504
2505         if (!ctlr->queued)
2506                 return 0;
2507
2508         ret = spi_start_queue(ctlr);
2509         if (ret)
2510                 dev_err(&ctlr->dev, "queue restart failed\n");
2511
2512         return ret;
2513 }
2514 EXPORT_SYMBOL_GPL(spi_controller_resume);
2515
2516 static int __spi_controller_match(struct device *dev, const void *data)
2517 {
2518         struct spi_controller *ctlr;
2519         const u16 *bus_num = data;
2520
2521         ctlr = container_of(dev, struct spi_controller, dev);
2522         return ctlr->bus_num == *bus_num;
2523 }
2524
2525 /**
2526  * spi_busnum_to_master - look up master associated with bus_num
2527  * @bus_num: the master's bus number
2528  * Context: can sleep
2529  *
2530  * This call may be used with devices that are registered after
2531  * arch init time.  It returns a refcounted pointer to the relevant
2532  * spi_controller (which the caller must release), or NULL if there is
2533  * no such master registered.
2534  *
2535  * Return: the SPI master structure on success, else NULL.
2536  */
2537 struct spi_controller *spi_busnum_to_master(u16 bus_num)
2538 {
2539         struct device           *dev;
2540         struct spi_controller   *ctlr = NULL;
2541
2542         dev = class_find_device(&spi_master_class, NULL, &bus_num,
2543                                 __spi_controller_match);
2544         if (dev)
2545                 ctlr = container_of(dev, struct spi_controller, dev);
2546         /* reference got in class_find_device */
2547         return ctlr;
2548 }
2549 EXPORT_SYMBOL_GPL(spi_busnum_to_master);
2550
2551 /*-------------------------------------------------------------------------*/
2552
2553 /* Core methods for SPI resource management */
2554
2555 /**
2556  * spi_res_alloc - allocate a spi resource that is life-cycle managed
2557  *                 during the processing of a spi_message while using
2558  *                 spi_transfer_one
2559  * @spi:     the spi device for which we allocate memory
2560  * @release: the release code to execute for this resource
2561  * @size:    size to alloc and return
2562  * @gfp:     GFP allocation flags
2563  *
2564  * Return: the pointer to the allocated data
2565  *
2566  * This may get enhanced in the future to allocate from a memory pool
2567  * of the @spi_device or @spi_controller to avoid repeated allocations.
2568  */
2569 void *spi_res_alloc(struct spi_device *spi,
2570                     spi_res_release_t release,
2571                     size_t size, gfp_t gfp)
2572 {
2573         struct spi_res *sres;
2574
2575         sres = kzalloc(sizeof(*sres) + size, gfp);
2576         if (!sres)
2577                 return NULL;
2578
2579         INIT_LIST_HEAD(&sres->entry);
2580         sres->release = release;
2581
2582         return sres->data;
2583 }
2584 EXPORT_SYMBOL_GPL(spi_res_alloc);
2585
2586 /**
2587  * spi_res_free - free an spi resource
2588  * @res: pointer to the custom data of a resource
2589  *
2590  */
2591 void spi_res_free(void *res)
2592 {
2593         struct spi_res *sres = container_of(res, struct spi_res, data);
2594
2595         if (!res)
2596                 return;
2597
2598         WARN_ON(!list_empty(&sres->entry));
2599         kfree(sres);
2600 }
2601 EXPORT_SYMBOL_GPL(spi_res_free);
2602
2603 /**
2604  * spi_res_add - add a spi_res to the spi_message
2605  * @message: the spi message
2606  * @res:     the spi_resource
2607  */
2608 void spi_res_add(struct spi_message *message, void *res)
2609 {
2610         struct spi_res *sres = container_of(res, struct spi_res, data);
2611
2612         WARN_ON(!list_empty(&sres->entry));
2613         list_add_tail(&sres->entry, &message->resources);
2614 }
2615 EXPORT_SYMBOL_GPL(spi_res_add);
2616
2617 /**
2618  * spi_res_release - release all spi resources for this message
2619  * @ctlr:  the @spi_controller
2620  * @message: the @spi_message
2621  */
2622 void spi_res_release(struct spi_controller *ctlr, struct spi_message *message)
2623 {
2624         struct spi_res *res;
2625
2626         while (!list_empty(&message->resources)) {
2627                 res = list_last_entry(&message->resources,
2628                                       struct spi_res, entry);
2629
2630                 if (res->release)
2631                         res->release(ctlr, message, res->data);
2632
2633                 list_del(&res->entry);
2634
2635                 kfree(res);
2636         }
2637 }
2638 EXPORT_SYMBOL_GPL(spi_res_release);
2639
2640 /*-------------------------------------------------------------------------*/
2641
2642 /* Core methods for spi_message alterations */
2643
2644 static void __spi_replace_transfers_release(struct spi_controller *ctlr,
2645                                             struct spi_message *msg,
2646                                             void *res)
2647 {
2648         struct spi_replaced_transfers *rxfer = res;
2649         size_t i;
2650
2651         /* call extra callback if requested */
2652         if (rxfer->release)
2653                 rxfer->release(ctlr, msg, res);
2654
2655         /* insert replaced transfers back into the message */
2656         list_splice(&rxfer->replaced_transfers, rxfer->replaced_after);
2657
2658         /* remove the formerly inserted entries */
2659         for (i = 0; i < rxfer->inserted; i++)
2660                 list_del(&rxfer->inserted_transfers[i].transfer_list);
2661 }
2662
2663 /**
2664  * spi_replace_transfers - replace transfers with several transfers
2665  *                         and register change with spi_message.resources
2666  * @msg:           the spi_message we work upon
2667  * @xfer_first:    the first spi_transfer we want to replace
2668  * @remove:        number of transfers to remove
2669  * @insert:        the number of transfers we want to insert instead
2670  * @release:       extra release code necessary in some circumstances
2671  * @extradatasize: extra data to allocate (with alignment guarantees
2672  *                 of struct @spi_transfer)
2673  * @gfp:           gfp flags
2674  *
2675  * Returns: pointer to @spi_replaced_transfers,
2676  *          PTR_ERR(...) in case of errors.
2677  */
2678 struct spi_replaced_transfers *spi_replace_transfers(
2679         struct spi_message *msg,
2680         struct spi_transfer *xfer_first,
2681         size_t remove,
2682         size_t insert,
2683         spi_replaced_release_t release,
2684         size_t extradatasize,
2685         gfp_t gfp)
2686 {
2687         struct spi_replaced_transfers *rxfer;
2688         struct spi_transfer *xfer;
2689         size_t i;
2690
2691         /* allocate the structure using spi_res */
2692         rxfer = spi_res_alloc(msg->spi, __spi_replace_transfers_release,
2693                               insert * sizeof(struct spi_transfer)
2694                               + sizeof(struct spi_replaced_transfers)
2695                               + extradatasize,
2696                               gfp);
2697         if (!rxfer)
2698                 return ERR_PTR(-ENOMEM);
2699
2700         /* the release code to invoke before running the generic release */
2701         rxfer->release = release;
2702
2703         /* assign extradata */
2704         if (extradatasize)
2705                 rxfer->extradata =
2706                         &rxfer->inserted_transfers[insert];
2707
2708         /* init the replaced_transfers list */
2709         INIT_LIST_HEAD(&rxfer->replaced_transfers);
2710
2711         /* assign the list_entry after which we should reinsert
2712          * the @replaced_transfers - it may be spi_message.messages!
2713          */
2714         rxfer->replaced_after = xfer_first->transfer_list.prev;
2715
2716         /* remove the requested number of transfers */
2717         for (i = 0; i < remove; i++) {
2718                 /* if the entry after replaced_after it is msg->transfers
2719                  * then we have been requested to remove more transfers
2720                  * than are in the list
2721                  */
2722                 if (rxfer->replaced_after->next == &msg->transfers) {
2723                         dev_err(&msg->spi->dev,
2724                                 "requested to remove more spi_transfers than are available\n");
2725                         /* insert replaced transfers back into the message */
2726                         list_splice(&rxfer->replaced_transfers,
2727                                     rxfer->replaced_after);
2728
2729                         /* free the spi_replace_transfer structure */
2730                         spi_res_free(rxfer);
2731
2732                         /* and return with an error */
2733                         return ERR_PTR(-EINVAL);
2734                 }
2735
2736                 /* remove the entry after replaced_after from list of
2737                  * transfers and add it to list of replaced_transfers
2738                  */
2739                 list_move_tail(rxfer->replaced_after->next,
2740                                &rxfer->replaced_transfers);
2741         }
2742
2743         /* create copy of the given xfer with identical settings
2744          * based on the first transfer to get removed
2745          */
2746         for (i = 0; i < insert; i++) {
2747                 /* we need to run in reverse order */
2748                 xfer = &rxfer->inserted_transfers[insert - 1 - i];
2749
2750                 /* copy all spi_transfer data */
2751                 memcpy(xfer, xfer_first, sizeof(*xfer));
2752
2753                 /* add to list */
2754                 list_add(&xfer->transfer_list, rxfer->replaced_after);
2755
2756                 /* clear cs_change and delay_usecs for all but the last */
2757                 if (i) {
2758                         xfer->cs_change = false;
2759                         xfer->delay_usecs = 0;
2760                 }
2761         }
2762
2763         /* set up inserted */
2764         rxfer->inserted = insert;
2765
2766         /* and register it with spi_res/spi_message */
2767         spi_res_add(msg, rxfer);
2768
2769         return rxfer;
2770 }
2771 EXPORT_SYMBOL_GPL(spi_replace_transfers);
2772
2773 static int __spi_split_transfer_maxsize(struct spi_controller *ctlr,
2774                                         struct spi_message *msg,
2775                                         struct spi_transfer **xferp,
2776                                         size_t maxsize,
2777                                         gfp_t gfp)
2778 {
2779         struct spi_transfer *xfer = *xferp, *xfers;
2780         struct spi_replaced_transfers *srt;
2781         size_t offset;
2782         size_t count, i;
2783
2784         /* warn once about this fact that we are splitting a transfer */
2785         dev_warn_once(&msg->spi->dev,
2786                       "spi_transfer of length %i exceed max length of %zu - needed to split transfers\n",
2787                       xfer->len, maxsize);
2788
2789         /* calculate how many we have to replace */
2790         count = DIV_ROUND_UP(xfer->len, maxsize);
2791
2792         /* create replacement */
2793         srt = spi_replace_transfers(msg, xfer, 1, count, NULL, 0, gfp);
2794         if (IS_ERR(srt))
2795                 return PTR_ERR(srt);
2796         xfers = srt->inserted_transfers;
2797
2798         /* now handle each of those newly inserted spi_transfers
2799          * note that the replacements spi_transfers all are preset
2800          * to the same values as *xferp, so tx_buf, rx_buf and len
2801          * are all identical (as well as most others)
2802          * so we just have to fix up len and the pointers.
2803          *
2804          * this also includes support for the depreciated
2805          * spi_message.is_dma_mapped interface
2806          */
2807
2808         /* the first transfer just needs the length modified, so we
2809          * run it outside the loop
2810          */
2811         xfers[0].len = min_t(size_t, maxsize, xfer[0].len);
2812
2813         /* all the others need rx_buf/tx_buf also set */
2814         for (i = 1, offset = maxsize; i < count; offset += maxsize, i++) {
2815                 /* update rx_buf, tx_buf and dma */
2816                 if (xfers[i].rx_buf)
2817                         xfers[i].rx_buf += offset;
2818                 if (xfers[i].rx_dma)
2819                         xfers[i].rx_dma += offset;
2820                 if (xfers[i].tx_buf)
2821                         xfers[i].tx_buf += offset;
2822                 if (xfers[i].tx_dma)
2823                         xfers[i].tx_dma += offset;
2824
2825                 /* update length */
2826                 xfers[i].len = min(maxsize, xfers[i].len - offset);
2827         }
2828
2829         /* we set up xferp to the last entry we have inserted,
2830          * so that we skip those already split transfers
2831          */
2832         *xferp = &xfers[count - 1];
2833
2834         /* increment statistics counters */
2835         SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics,
2836                                        transfers_split_maxsize);
2837         SPI_STATISTICS_INCREMENT_FIELD(&msg->spi->statistics,
2838                                        transfers_split_maxsize);
2839
2840         return 0;
2841 }
2842
2843 /**
2844  * spi_split_tranfers_maxsize - split spi transfers into multiple transfers
2845  *                              when an individual transfer exceeds a
2846  *                              certain size
2847  * @ctlr:    the @spi_controller for this transfer
2848  * @msg:   the @spi_message to transform
2849  * @maxsize:  the maximum when to apply this
2850  * @gfp: GFP allocation flags
2851  *
2852  * Return: status of transformation
2853  */
2854 int spi_split_transfers_maxsize(struct spi_controller *ctlr,
2855                                 struct spi_message *msg,
2856                                 size_t maxsize,
2857                                 gfp_t gfp)
2858 {
2859         struct spi_transfer *xfer;
2860         int ret;
2861
2862         /* iterate over the transfer_list,
2863          * but note that xfer is advanced to the last transfer inserted
2864          * to avoid checking sizes again unnecessarily (also xfer does
2865          * potentiall belong to a different list by the time the
2866          * replacement has happened
2867          */
2868         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
2869                 if (xfer->len > maxsize) {
2870                         ret = __spi_split_transfer_maxsize(ctlr, msg, &xfer,
2871                                                            maxsize, gfp);
2872                         if (ret)
2873                                 return ret;
2874                 }
2875         }
2876
2877         return 0;
2878 }
2879 EXPORT_SYMBOL_GPL(spi_split_transfers_maxsize);
2880
2881 /*-------------------------------------------------------------------------*/
2882
2883 /* Core methods for SPI controller protocol drivers.  Some of the
2884  * other core methods are currently defined as inline functions.
2885  */
2886
2887 static int __spi_validate_bits_per_word(struct spi_controller *ctlr,
2888                                         u8 bits_per_word)
2889 {
2890         if (ctlr->bits_per_word_mask) {
2891                 /* Only 32 bits fit in the mask */
2892                 if (bits_per_word > 32)
2893                         return -EINVAL;
2894                 if (!(ctlr->bits_per_word_mask & SPI_BPW_MASK(bits_per_word)))
2895                         return -EINVAL;
2896         }
2897
2898         return 0;
2899 }
2900
2901 /**
2902  * spi_setup - setup SPI mode and clock rate
2903  * @spi: the device whose settings are being modified
2904  * Context: can sleep, and no requests are queued to the device
2905  *
2906  * SPI protocol drivers may need to update the transfer mode if the
2907  * device doesn't work with its default.  They may likewise need
2908  * to update clock rates or word sizes from initial values.  This function
2909  * changes those settings, and must be called from a context that can sleep.
2910  * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
2911  * effect the next time the device is selected and data is transferred to
2912  * or from it.  When this function returns, the spi device is deselected.
2913  *
2914  * Note that this call will fail if the protocol driver specifies an option
2915  * that the underlying controller or its driver does not support.  For
2916  * example, not all hardware supports wire transfers using nine bit words,
2917  * LSB-first wire encoding, or active-high chipselects.
2918  *
2919  * Return: zero on success, else a negative error code.
2920  */
2921 int spi_setup(struct spi_device *spi)
2922 {
2923         unsigned        bad_bits, ugly_bits;
2924         int             status;
2925
2926         /* check mode to prevent that DUAL and QUAD set at the same time
2927          */
2928         if (((spi->mode & SPI_TX_DUAL) && (spi->mode & SPI_TX_QUAD)) ||
2929                 ((spi->mode & SPI_RX_DUAL) && (spi->mode & SPI_RX_QUAD))) {
2930                 dev_err(&spi->dev,
2931                 "setup: can not select dual and quad at the same time\n");
2932                 return -EINVAL;
2933         }
2934         /* if it is SPI_3WIRE mode, DUAL and QUAD should be forbidden
2935          */
2936         if ((spi->mode & SPI_3WIRE) && (spi->mode &
2937                 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_TX_OCTAL |
2938                  SPI_RX_DUAL | SPI_RX_QUAD | SPI_RX_OCTAL)))
2939                 return -EINVAL;
2940         /* help drivers fail *cleanly* when they need options
2941          * that aren't supported with their current controller
2942          * SPI_CS_WORD has a fallback software implementation,
2943          * so it is ignored here.
2944          */
2945         bad_bits = spi->mode & ~(spi->controller->mode_bits | SPI_CS_WORD);
2946         ugly_bits = bad_bits &
2947                     (SPI_TX_DUAL | SPI_TX_QUAD | SPI_TX_OCTAL |
2948                      SPI_RX_DUAL | SPI_RX_QUAD | SPI_RX_OCTAL);
2949         if (ugly_bits) {
2950                 dev_warn(&spi->dev,
2951                          "setup: ignoring unsupported mode bits %x\n",
2952                          ugly_bits);
2953                 spi->mode &= ~ugly_bits;
2954                 bad_bits &= ~ugly_bits;
2955         }
2956         if (bad_bits) {
2957                 dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
2958                         bad_bits);
2959                 return -EINVAL;
2960         }
2961
2962         if (!spi->bits_per_word)
2963                 spi->bits_per_word = 8;
2964
2965         status = __spi_validate_bits_per_word(spi->controller,
2966                                               spi->bits_per_word);
2967         if (status)
2968                 return status;
2969
2970         if (!spi->max_speed_hz)
2971                 spi->max_speed_hz = spi->controller->max_speed_hz;
2972
2973         if (spi->controller->setup)
2974                 status = spi->controller->setup(spi);
2975
2976         spi_set_cs(spi, false);
2977
2978         dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
2979                         (int) (spi->mode & (SPI_CPOL | SPI_CPHA)),
2980                         (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
2981                         (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
2982                         (spi->mode & SPI_3WIRE) ? "3wire, " : "",
2983                         (spi->mode & SPI_LOOP) ? "loopback, " : "",
2984                         spi->bits_per_word, spi->max_speed_hz,
2985                         status);
2986
2987         return status;
2988 }
2989 EXPORT_SYMBOL_GPL(spi_setup);
2990
2991 static int __spi_validate(struct spi_device *spi, struct spi_message *message)
2992 {
2993         struct spi_controller *ctlr = spi->controller;
2994         struct spi_transfer *xfer;
2995         int w_size;
2996
2997         if (list_empty(&message->transfers))
2998                 return -EINVAL;
2999
3000         /* If an SPI controller does not support toggling the CS line on each
3001          * transfer (indicated by the SPI_CS_WORD flag) or we are using a GPIO
3002          * for the CS line, we can emulate the CS-per-word hardware function by
3003          * splitting transfers into one-word transfers and ensuring that
3004          * cs_change is set for each transfer.
3005          */
3006         if ((spi->mode & SPI_CS_WORD) && (!(ctlr->mode_bits & SPI_CS_WORD) ||
3007                                           spi->cs_gpiod ||
3008                                           gpio_is_valid(spi->cs_gpio))) {
3009                 size_t maxsize;
3010                 int ret;
3011
3012                 maxsize = (spi->bits_per_word + 7) / 8;
3013
3014                 /* spi_split_transfers_maxsize() requires message->spi */
3015                 message->spi = spi;
3016
3017                 ret = spi_split_transfers_maxsize(ctlr, message, maxsize,
3018                                                   GFP_KERNEL);
3019                 if (ret)
3020                         return ret;
3021
3022                 list_for_each_entry(xfer, &message->transfers, transfer_list) {
3023                         /* don't change cs_change on the last entry in the list */
3024                         if (list_is_last(&xfer->transfer_list, &message->transfers))
3025                                 break;
3026                         xfer->cs_change = 1;
3027                 }
3028         }
3029
3030         /* Half-duplex links include original MicroWire, and ones with
3031          * only one data pin like SPI_3WIRE (switches direction) or where
3032          * either MOSI or MISO is missing.  They can also be caused by
3033          * software limitations.
3034          */
3035         if ((ctlr->flags & SPI_CONTROLLER_HALF_DUPLEX) ||
3036             (spi->mode & SPI_3WIRE)) {
3037                 unsigned flags = ctlr->flags;
3038
3039                 list_for_each_entry(xfer, &message->transfers, transfer_list) {
3040                         if (xfer->rx_buf && xfer->tx_buf)
3041                                 return -EINVAL;
3042                         if ((flags & SPI_CONTROLLER_NO_TX) && xfer->tx_buf)
3043                                 return -EINVAL;
3044                         if ((flags & SPI_CONTROLLER_NO_RX) && xfer->rx_buf)
3045                                 return -EINVAL;
3046                 }
3047         }
3048
3049         /**
3050          * Set transfer bits_per_word and max speed as spi device default if
3051          * it is not set for this transfer.
3052          * Set transfer tx_nbits and rx_nbits as single transfer default
3053          * (SPI_NBITS_SINGLE) if it is not set for this transfer.
3054          * Ensure transfer word_delay is at least as long as that required by
3055          * device itself.
3056          */
3057         message->frame_length = 0;
3058         list_for_each_entry(xfer, &message->transfers, transfer_list) {
3059                 message->frame_length += xfer->len;
3060                 if (!xfer->bits_per_word)
3061                         xfer->bits_per_word = spi->bits_per_word;
3062
3063                 if (!xfer->speed_hz)
3064                         xfer->speed_hz = spi->max_speed_hz;
3065                 if (!xfer->speed_hz)
3066                         xfer->speed_hz = ctlr->max_speed_hz;
3067
3068                 if (ctlr->max_speed_hz && xfer->speed_hz > ctlr->max_speed_hz)
3069                         xfer->speed_hz = ctlr->max_speed_hz;
3070
3071                 if (__spi_validate_bits_per_word(ctlr, xfer->bits_per_word))
3072                         return -EINVAL;
3073
3074                 /*
3075                  * SPI transfer length should be multiple of SPI word size
3076                  * where SPI word size should be power-of-two multiple
3077                  */
3078                 if (xfer->bits_per_word <= 8)
3079                         w_size = 1;
3080                 else if (xfer->bits_per_word <= 16)
3081                         w_size = 2;
3082                 else
3083                         w_size = 4;
3084
3085                 /* No partial transfers accepted */
3086                 if (xfer->len % w_size)
3087                         return -EINVAL;
3088
3089                 if (xfer->speed_hz && ctlr->min_speed_hz &&
3090                     xfer->speed_hz < ctlr->min_speed_hz)
3091                         return -EINVAL;
3092
3093                 if (xfer->tx_buf && !xfer->tx_nbits)
3094                         xfer->tx_nbits = SPI_NBITS_SINGLE;
3095                 if (xfer->rx_buf && !xfer->rx_nbits)
3096                         xfer->rx_nbits = SPI_NBITS_SINGLE;
3097                 /* check transfer tx/rx_nbits:
3098                  * 1. check the value matches one of single, dual and quad
3099                  * 2. check tx/rx_nbits match the mode in spi_device
3100                  */
3101                 if (xfer->tx_buf) {
3102                         if (xfer->tx_nbits != SPI_NBITS_SINGLE &&
3103                                 xfer->tx_nbits != SPI_NBITS_DUAL &&
3104                                 xfer->tx_nbits != SPI_NBITS_QUAD)
3105                                 return -EINVAL;
3106                         if ((xfer->tx_nbits == SPI_NBITS_DUAL) &&
3107                                 !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
3108                                 return -EINVAL;
3109                         if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
3110                                 !(spi->mode & SPI_TX_QUAD))
3111                                 return -EINVAL;
3112                 }
3113                 /* check transfer rx_nbits */
3114                 if (xfer->rx_buf) {
3115                         if (xfer->rx_nbits != SPI_NBITS_SINGLE &&
3116                                 xfer->rx_nbits != SPI_NBITS_DUAL &&
3117                                 xfer->rx_nbits != SPI_NBITS_QUAD)
3118                                 return -EINVAL;
3119                         if ((xfer->rx_nbits == SPI_NBITS_DUAL) &&
3120                                 !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
3121                                 return -EINVAL;
3122                         if ((xfer->rx_nbits == SPI_NBITS_QUAD) &&
3123                                 !(spi->mode & SPI_RX_QUAD))
3124                                 return -EINVAL;
3125                 }
3126
3127                 if (xfer->word_delay_usecs < spi->word_delay_usecs)
3128                         xfer->word_delay_usecs = spi->word_delay_usecs;
3129         }
3130
3131         message->status = -EINPROGRESS;
3132
3133         return 0;
3134 }
3135
3136 static int __spi_async(struct spi_device *spi, struct spi_message *message)
3137 {
3138         struct spi_controller *ctlr = spi->controller;
3139
3140         /*
3141          * Some controllers do not support doing regular SPI transfers. Return
3142          * ENOTSUPP when this is the case.
3143          */
3144         if (!ctlr->transfer)
3145                 return -ENOTSUPP;
3146
3147         message->spi = spi;
3148
3149         SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics, spi_async);
3150         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_async);
3151
3152         trace_spi_message_submit(message);
3153
3154         return ctlr->transfer(spi, message);
3155 }
3156
3157 /**
3158  * spi_async - asynchronous SPI transfer
3159  * @spi: device with which data will be exchanged
3160  * @message: describes the data transfers, including completion callback
3161  * Context: any (irqs may be blocked, etc)
3162  *
3163  * This call may be used in_irq and other contexts which can't sleep,
3164  * as well as from task contexts which can sleep.
3165  *
3166  * The completion callback is invoked in a context which can't sleep.
3167  * Before that invocation, the value of message->status is undefined.
3168  * When the callback is issued, message->status holds either zero (to
3169  * indicate complete success) or a negative error code.  After that
3170  * callback returns, the driver which issued the transfer request may
3171  * deallocate the associated memory; it's no longer in use by any SPI
3172  * core or controller driver code.
3173  *
3174  * Note that although all messages to a spi_device are handled in
3175  * FIFO order, messages may go to different devices in other orders.
3176  * Some device might be higher priority, or have various "hard" access
3177  * time requirements, for example.
3178  *
3179  * On detection of any fault during the transfer, processing of
3180  * the entire message is aborted, and the device is deselected.
3181  * Until returning from the associated message completion callback,
3182  * no other spi_message queued to that device will be processed.
3183  * (This rule applies equally to all the synchronous transfer calls,
3184  * which are wrappers around this core asynchronous primitive.)
3185  *
3186  * Return: zero on success, else a negative error code.
3187  */
3188 int spi_async(struct spi_device *spi, struct spi_message *message)
3189 {
3190         struct spi_controller *ctlr = spi->controller;
3191         int ret;
3192         unsigned long flags;
3193
3194         ret = __spi_validate(spi, message);
3195         if (ret != 0)
3196                 return ret;
3197
3198         spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
3199
3200         if (ctlr->bus_lock_flag)
3201                 ret = -EBUSY;
3202         else
3203                 ret = __spi_async(spi, message);
3204
3205         spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3206
3207         return ret;
3208 }
3209 EXPORT_SYMBOL_GPL(spi_async);
3210
3211 /**
3212  * spi_async_locked - version of spi_async with exclusive bus usage
3213  * @spi: device with which data will be exchanged
3214  * @message: describes the data transfers, including completion callback
3215  * Context: any (irqs may be blocked, etc)
3216  *
3217  * This call may be used in_irq and other contexts which can't sleep,
3218  * as well as from task contexts which can sleep.
3219  *
3220  * The completion callback is invoked in a context which can't sleep.
3221  * Before that invocation, the value of message->status is undefined.
3222  * When the callback is issued, message->status holds either zero (to
3223  * indicate complete success) or a negative error code.  After that
3224  * callback returns, the driver which issued the transfer request may
3225  * deallocate the associated memory; it's no longer in use by any SPI
3226  * core or controller driver code.
3227  *
3228  * Note that although all messages to a spi_device are handled in
3229  * FIFO order, messages may go to different devices in other orders.
3230  * Some device might be higher priority, or have various "hard" access
3231  * time requirements, for example.
3232  *
3233  * On detection of any fault during the transfer, processing of
3234  * the entire message is aborted, and the device is deselected.
3235  * Until returning from the associated message completion callback,
3236  * no other spi_message queued to that device will be processed.
3237  * (This rule applies equally to all the synchronous transfer calls,
3238  * which are wrappers around this core asynchronous primitive.)
3239  *
3240  * Return: zero on success, else a negative error code.
3241  */
3242 int spi_async_locked(struct spi_device *spi, struct spi_message *message)
3243 {
3244         struct spi_controller *ctlr = spi->controller;
3245         int ret;
3246         unsigned long flags;
3247
3248         ret = __spi_validate(spi, message);
3249         if (ret != 0)
3250                 return ret;
3251
3252         spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
3253
3254         ret = __spi_async(spi, message);
3255
3256         spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3257
3258         return ret;
3259
3260 }
3261 EXPORT_SYMBOL_GPL(spi_async_locked);
3262
3263 /*-------------------------------------------------------------------------*/
3264
3265 /* Utility methods for SPI protocol drivers, layered on
3266  * top of the core.  Some other utility methods are defined as
3267  * inline functions.
3268  */
3269
3270 static void spi_complete(void *arg)
3271 {
3272         complete(arg);
3273 }
3274
3275 static int __spi_sync(struct spi_device *spi, struct spi_message *message)
3276 {
3277         DECLARE_COMPLETION_ONSTACK(done);
3278         int status;
3279         struct spi_controller *ctlr = spi->controller;
3280         unsigned long flags;
3281
3282         status = __spi_validate(spi, message);
3283         if (status != 0)
3284                 return status;
3285
3286         message->complete = spi_complete;
3287         message->context = &done;
3288         message->spi = spi;
3289
3290         SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics, spi_sync);
3291         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_sync);
3292
3293         /* If we're not using the legacy transfer method then we will
3294          * try to transfer in the calling context so special case.
3295          * This code would be less tricky if we could remove the
3296          * support for driver implemented message queues.
3297          */
3298         if (ctlr->transfer == spi_queued_transfer) {
3299                 spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
3300
3301                 trace_spi_message_submit(message);
3302
3303                 status = __spi_queued_transfer(spi, message, false);
3304
3305                 spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3306         } else {
3307                 status = spi_async_locked(spi, message);
3308         }
3309
3310         if (status == 0) {
3311                 /* Push out the messages in the calling context if we
3312                  * can.
3313                  */
3314                 if (ctlr->transfer == spi_queued_transfer) {
3315                         SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics,
3316                                                        spi_sync_immediate);
3317                         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics,
3318                                                        spi_sync_immediate);
3319                         __spi_pump_messages(ctlr, false);
3320                 }
3321
3322                 wait_for_completion(&done);
3323                 status = message->status;
3324         }
3325         message->context = NULL;
3326         return status;
3327 }
3328
3329 /**
3330  * spi_sync - blocking/synchronous SPI data transfers
3331  * @spi: device with which data will be exchanged
3332  * @message: describes the data transfers
3333  * Context: can sleep
3334  *
3335  * This call may only be used from a context that may sleep.  The sleep
3336  * is non-interruptible, and has no timeout.  Low-overhead controller
3337  * drivers may DMA directly into and out of the message buffers.
3338  *
3339  * Note that the SPI device's chip select is active during the message,
3340  * and then is normally disabled between messages.  Drivers for some
3341  * frequently-used devices may want to minimize costs of selecting a chip,
3342  * by leaving it selected in anticipation that the next message will go
3343  * to the same chip.  (That may increase power usage.)
3344  *
3345  * Also, the caller is guaranteeing that the memory associated with the
3346  * message will not be freed before this call returns.
3347  *
3348  * Return: zero on success, else a negative error code.
3349  */
3350 int spi_sync(struct spi_device *spi, struct spi_message *message)
3351 {
3352         int ret;
3353
3354         mutex_lock(&spi->controller->bus_lock_mutex);
3355         ret = __spi_sync(spi, message);
3356         mutex_unlock(&spi->controller->bus_lock_mutex);
3357
3358         return ret;
3359 }
3360 EXPORT_SYMBOL_GPL(spi_sync);
3361
3362 /**
3363  * spi_sync_locked - version of spi_sync with exclusive bus usage
3364  * @spi: device with which data will be exchanged
3365  * @message: describes the data transfers
3366  * Context: can sleep
3367  *
3368  * This call may only be used from a context that may sleep.  The sleep
3369  * is non-interruptible, and has no timeout.  Low-overhead controller
3370  * drivers may DMA directly into and out of the message buffers.
3371  *
3372  * This call should be used by drivers that require exclusive access to the
3373  * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
3374  * be released by a spi_bus_unlock call when the exclusive access is over.
3375  *
3376  * Return: zero on success, else a negative error code.
3377  */
3378 int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
3379 {
3380         return __spi_sync(spi, message);
3381 }
3382 EXPORT_SYMBOL_GPL(spi_sync_locked);
3383
3384 /**
3385  * spi_bus_lock - obtain a lock for exclusive SPI bus usage
3386  * @ctlr: SPI bus master that should be locked for exclusive bus access
3387  * Context: can sleep
3388  *
3389  * This call may only be used from a context that may sleep.  The sleep
3390  * is non-interruptible, and has no timeout.
3391  *
3392  * This call should be used by drivers that require exclusive access to the
3393  * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
3394  * exclusive access is over. Data transfer must be done by spi_sync_locked
3395  * and spi_async_locked calls when the SPI bus lock is held.
3396  *
3397  * Return: always zero.
3398  */
3399 int spi_bus_lock(struct spi_controller *ctlr)
3400 {
3401         unsigned long flags;
3402
3403         mutex_lock(&ctlr->bus_lock_mutex);
3404
3405         spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
3406         ctlr->bus_lock_flag = 1;
3407         spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3408
3409         /* mutex remains locked until spi_bus_unlock is called */
3410
3411         return 0;
3412 }
3413 EXPORT_SYMBOL_GPL(spi_bus_lock);
3414
3415 /**
3416  * spi_bus_unlock - release the lock for exclusive SPI bus usage
3417  * @ctlr: SPI bus master that was locked for exclusive bus access
3418  * Context: can sleep
3419  *
3420  * This call may only be used from a context that may sleep.  The sleep
3421  * is non-interruptible, and has no timeout.
3422  *
3423  * This call releases an SPI bus lock previously obtained by an spi_bus_lock
3424  * call.
3425  *
3426  * Return: always zero.
3427  */
3428 int spi_bus_unlock(struct spi_controller *ctlr)
3429 {
3430         ctlr->bus_lock_flag = 0;
3431
3432         mutex_unlock(&ctlr->bus_lock_mutex);
3433
3434         return 0;
3435 }
3436 EXPORT_SYMBOL_GPL(spi_bus_unlock);
3437
3438 /* portable code must never pass more than 32 bytes */
3439 #define SPI_BUFSIZ      max(32, SMP_CACHE_BYTES)
3440
3441 static u8       *buf;
3442
3443 /**
3444  * spi_write_then_read - SPI synchronous write followed by read
3445  * @spi: device with which data will be exchanged
3446  * @txbuf: data to be written (need not be dma-safe)
3447  * @n_tx: size of txbuf, in bytes
3448  * @rxbuf: buffer into which data will be read (need not be dma-safe)
3449  * @n_rx: size of rxbuf, in bytes
3450  * Context: can sleep
3451  *
3452  * This performs a half duplex MicroWire style transaction with the
3453  * device, sending txbuf and then reading rxbuf.  The return value
3454  * is zero for success, else a negative errno status code.
3455  * This call may only be used from a context that may sleep.
3456  *
3457  * Parameters to this routine are always copied using a small buffer;
3458  * portable code should never use this for more than 32 bytes.
3459  * Performance-sensitive or bulk transfer code should instead use
3460  * spi_{async,sync}() calls with dma-safe buffers.
3461  *
3462  * Return: zero on success, else a negative error code.
3463  */
3464 int spi_write_then_read(struct spi_device *spi,
3465                 const void *txbuf, unsigned n_tx,
3466                 void *rxbuf, unsigned n_rx)
3467 {
3468         static DEFINE_MUTEX(lock);
3469
3470         int                     status;
3471         struct spi_message      message;
3472         struct spi_transfer     x[2];
3473         u8                      *local_buf;
3474
3475         /* Use preallocated DMA-safe buffer if we can.  We can't avoid
3476          * copying here, (as a pure convenience thing), but we can
3477          * keep heap costs out of the hot path unless someone else is
3478          * using the pre-allocated buffer or the transfer is too large.
3479          */
3480         if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) {
3481                 local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx),
3482                                     GFP_KERNEL | GFP_DMA);
3483                 if (!local_buf)
3484                         return -ENOMEM;
3485         } else {
3486                 local_buf = buf;
3487         }
3488
3489         spi_message_init(&message);
3490         memset(x, 0, sizeof(x));
3491         if (n_tx) {
3492                 x[0].len = n_tx;
3493                 spi_message_add_tail(&x[0], &message);
3494         }
3495         if (n_rx) {
3496                 x[1].len = n_rx;
3497                 spi_message_add_tail(&x[1], &message);
3498         }
3499
3500         memcpy(local_buf, txbuf, n_tx);
3501         x[0].tx_buf = local_buf;
3502         x[1].rx_buf = local_buf + n_tx;
3503
3504         /* do the i/o */
3505         status = spi_sync(spi, &message);
3506         if (status == 0)
3507                 memcpy(rxbuf, x[1].rx_buf, n_rx);
3508
3509         if (x[0].tx_buf == buf)
3510                 mutex_unlock(&lock);
3511         else
3512                 kfree(local_buf);
3513
3514         return status;
3515 }
3516 EXPORT_SYMBOL_GPL(spi_write_then_read);
3517
3518 /*-------------------------------------------------------------------------*/
3519
3520 #if IS_ENABLED(CONFIG_OF)
3521 static int __spi_of_device_match(struct device *dev, void *data)
3522 {
3523         return dev->of_node == data;
3524 }
3525
3526 /* must call put_device() when done with returned spi_device device */
3527 struct spi_device *of_find_spi_device_by_node(struct device_node *node)
3528 {
3529         struct device *dev = bus_find_device(&spi_bus_type, NULL, node,
3530                                                 __spi_of_device_match);
3531         return dev ? to_spi_device(dev) : NULL;
3532 }
3533 EXPORT_SYMBOL_GPL(of_find_spi_device_by_node);
3534 #endif /* IS_ENABLED(CONFIG_OF) */
3535
3536 #if IS_ENABLED(CONFIG_OF_DYNAMIC)
3537 static int __spi_of_controller_match(struct device *dev, const void *data)
3538 {
3539         return dev->of_node == data;
3540 }
3541
3542 /* the spi controllers are not using spi_bus, so we find it with another way */
3543 static struct spi_controller *of_find_spi_controller_by_node(struct device_node *node)
3544 {
3545         struct device *dev;
3546
3547         dev = class_find_device(&spi_master_class, NULL, node,
3548                                 __spi_of_controller_match);
3549         if (!dev && IS_ENABLED(CONFIG_SPI_SLAVE))
3550                 dev = class_find_device(&spi_slave_class, NULL, node,
3551                                         __spi_of_controller_match);
3552         if (!dev)
3553                 return NULL;
3554
3555         /* reference got in class_find_device */
3556         return container_of(dev, struct spi_controller, dev);
3557 }
3558
3559 static int of_spi_notify(struct notifier_block *nb, unsigned long action,
3560                          void *arg)
3561 {
3562         struct of_reconfig_data *rd = arg;
3563         struct spi_controller *ctlr;
3564         struct spi_device *spi;
3565
3566         switch (of_reconfig_get_state_change(action, arg)) {
3567         case OF_RECONFIG_CHANGE_ADD:
3568                 ctlr = of_find_spi_controller_by_node(rd->dn->parent);
3569                 if (ctlr == NULL)
3570                         return NOTIFY_OK;       /* not for us */
3571
3572                 if (of_node_test_and_set_flag(rd->dn, OF_POPULATED)) {
3573                         put_device(&ctlr->dev);
3574                         return NOTIFY_OK;
3575                 }
3576
3577                 spi = of_register_spi_device(ctlr, rd->dn);
3578                 put_device(&ctlr->dev);
3579
3580                 if (IS_ERR(spi)) {
3581                         pr_err("%s: failed to create for '%pOF'\n",
3582                                         __func__, rd->dn);
3583                         of_node_clear_flag(rd->dn, OF_POPULATED);
3584                         return notifier_from_errno(PTR_ERR(spi));
3585                 }
3586                 break;
3587
3588         case OF_RECONFIG_CHANGE_REMOVE:
3589                 /* already depopulated? */
3590                 if (!of_node_check_flag(rd->dn, OF_POPULATED))
3591                         return NOTIFY_OK;
3592
3593                 /* find our device by node */
3594                 spi = of_find_spi_device_by_node(rd->dn);
3595                 if (spi == NULL)
3596                         return NOTIFY_OK;       /* no? not meant for us */
3597
3598                 /* unregister takes one ref away */
3599                 spi_unregister_device(spi);
3600
3601                 /* and put the reference of the find */
3602                 put_device(&spi->dev);
3603                 break;
3604         }
3605
3606         return NOTIFY_OK;
3607 }
3608
3609 static struct notifier_block spi_of_notifier = {
3610         .notifier_call = of_spi_notify,
3611 };
3612 #else /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
3613 extern struct notifier_block spi_of_notifier;
3614 #endif /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
3615
3616 #if IS_ENABLED(CONFIG_ACPI)
3617 static int spi_acpi_controller_match(struct device *dev, const void *data)
3618 {
3619         return ACPI_COMPANION(dev->parent) == data;
3620 }
3621
3622 static int spi_acpi_device_match(struct device *dev, void *data)
3623 {
3624         return ACPI_COMPANION(dev) == data;
3625 }
3626
3627 static struct spi_controller *acpi_spi_find_controller_by_adev(struct acpi_device *adev)
3628 {
3629         struct device *dev;
3630
3631         dev = class_find_device(&spi_master_class, NULL, adev,
3632                                 spi_acpi_controller_match);
3633         if (!dev && IS_ENABLED(CONFIG_SPI_SLAVE))
3634                 dev = class_find_device(&spi_slave_class, NULL, adev,
3635                                         spi_acpi_controller_match);
3636         if (!dev)
3637                 return NULL;
3638
3639         return container_of(dev, struct spi_controller, dev);
3640 }
3641
3642 static struct spi_device *acpi_spi_find_device_by_adev(struct acpi_device *adev)
3643 {
3644         struct device *dev;
3645
3646         dev = bus_find_device(&spi_bus_type, NULL, adev, spi_acpi_device_match);
3647
3648         return dev ? to_spi_device(dev) : NULL;
3649 }
3650
3651 static int acpi_spi_notify(struct notifier_block *nb, unsigned long value,
3652                            void *arg)
3653 {
3654         struct acpi_device *adev = arg;
3655         struct spi_controller *ctlr;
3656         struct spi_device *spi;
3657
3658         switch (value) {
3659         case ACPI_RECONFIG_DEVICE_ADD:
3660                 ctlr = acpi_spi_find_controller_by_adev(adev->parent);
3661                 if (!ctlr)
3662                         break;
3663
3664                 acpi_register_spi_device(ctlr, adev);
3665                 put_device(&ctlr->dev);
3666                 break;
3667         case ACPI_RECONFIG_DEVICE_REMOVE:
3668                 if (!acpi_device_enumerated(adev))
3669                         break;
3670
3671                 spi = acpi_spi_find_device_by_adev(adev);
3672                 if (!spi)
3673                         break;
3674
3675                 spi_unregister_device(spi);
3676                 put_device(&spi->dev);
3677                 break;
3678         }
3679
3680         return NOTIFY_OK;
3681 }
3682
3683 static struct notifier_block spi_acpi_notifier = {
3684         .notifier_call = acpi_spi_notify,
3685 };
3686 #else
3687 extern struct notifier_block spi_acpi_notifier;
3688 #endif
3689
3690 static int __init spi_init(void)
3691 {
3692         int     status;
3693
3694         buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
3695         if (!buf) {
3696                 status = -ENOMEM;
3697                 goto err0;
3698         }
3699
3700         status = bus_register(&spi_bus_type);
3701         if (status < 0)
3702                 goto err1;
3703
3704         status = class_register(&spi_master_class);
3705         if (status < 0)
3706                 goto err2;
3707
3708         if (IS_ENABLED(CONFIG_SPI_SLAVE)) {
3709                 status = class_register(&spi_slave_class);
3710                 if (status < 0)
3711                         goto err3;
3712         }
3713
3714         if (IS_ENABLED(CONFIG_OF_DYNAMIC))
3715                 WARN_ON(of_reconfig_notifier_register(&spi_of_notifier));
3716         if (IS_ENABLED(CONFIG_ACPI))
3717                 WARN_ON(acpi_reconfig_notifier_register(&spi_acpi_notifier));
3718
3719         return 0;
3720
3721 err3:
3722         class_unregister(&spi_master_class);
3723 err2:
3724         bus_unregister(&spi_bus_type);
3725 err1:
3726         kfree(buf);
3727         buf = NULL;
3728 err0:
3729         return status;
3730 }
3731
3732 /* board_info is normally registered in arch_initcall(),
3733  * but even essential drivers wait till later
3734  *
3735  * REVISIT only boardinfo really needs static linking. the rest (device and
3736  * driver registration) _could_ be dynamically linked (modular) ... costs
3737  * include needing to have boardinfo data structures be much more public.
3738  */
3739 postcore_initcall(spi_init);
3740