drivers/spi/spi.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 // SPI init/core code
   3 //
   4 // Copyright (C) 2005 David Brownell
   5 // Copyright (C) 2008 Secret Lab Technologies Ltd.
   6
   7 #include <linux/kernel.h>
   8 #include <linux/device.h>
   9 #include <linux/init.h>
  10 #include <linux/cache.h>
  11 #include <linux/dma-mapping.h>
  12 #include <linux/dmaengine.h>
  13 #include <linux/mutex.h>
  14 #include <linux/of_device.h>
  15 #include <linux/of_irq.h>
  16 #include <linux/clk/clk-conf.h>
  17 #include <linux/slab.h>
  18 #include <linux/mod_devicetable.h>
  19 #include <linux/spi/spi.h>
  20 #include <linux/spi/spi-mem.h>
  21 #include <linux/of_gpio.h>
  22 #include <linux/gpio/consumer.h>
  23 #include <linux/pm_runtime.h>
  24 #include <linux/pm_domain.h>
  25 #include <linux/property.h>
  26 #include <linux/export.h>
  27 #include <linux/sched/rt.h>
  28 #include <uapi/linux/sched/types.h>
  29 #include <linux/delay.h>
  30 #include <linux/kthread.h>
  31 #include <linux/ioport.h>
  32 #include <linux/acpi.h>
  33 #include <linux/highmem.h>
  34 #include <linux/idr.h>
  35 #include <linux/platform_data/x86/apple.h>
  36
  37 #define CREATE_TRACE_POINTS
  38 #include <trace/events/spi.h>
  39 EXPORT_TRACEPOINT_SYMBOL(spi_transfer_start);
  40 EXPORT_TRACEPOINT_SYMBOL(spi_transfer_stop);
  41
  42 #include "internals.h"
  43
  44 static DEFINE_IDR(spi_master_idr);
  45
  46 static void spidev_release(struct device *dev)
  47 {
  48         struct spi_device       *spi = to_spi_device(dev);
  49
  50         /* spi controllers may cleanup for released devices */
  51         if (spi->controller->cleanup)
  52                 spi->controller->cleanup(spi);
  53
  54         spi_controller_put(spi->controller);
  55         kfree(spi->driver_override);
  56         kfree(spi);
  57 }
  58
  59 static ssize_t
  60 modalias_show(struct device *dev, struct device_attribute *a, char *buf)
  61 {
  62         const struct spi_device *spi = to_spi_device(dev);
  63         int len;
  64
  65         len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1);
  66         if (len != -ENODEV)
  67                 return len;
  68
  69         return sprintf(buf, "%s%s\n", SPI_MODULE_PREFIX, spi->modalias);
  70 }
  71 static DEVICE_ATTR_RO(modalias);
  72
  73 static ssize_t driver_override_store(struct device *dev,
  74                                      struct device_attribute *a,
  75                                      const char *buf, size_t count)
  76 {
  77         struct spi_device *spi = to_spi_device(dev);
  78         const char *end = memchr(buf, '\n', count);
  79         const size_t len = end ? end - buf : count;
  80         const char *driver_override, *old;
  81
  82         /* We need to keep extra room for a newline when displaying value */
  83         if (len >= (PAGE_SIZE - 1))
  84                 return -EINVAL;
  85
  86         driver_override = kstrndup(buf, len, GFP_KERNEL);
  87         if (!driver_override)
  88                 return -ENOMEM;
  89
  90         device_lock(dev);
  91         old = spi->driver_override;
  92         if (len) {
  93                 spi->driver_override = driver_override;
  94         } else {
  95                 /* Emptry string, disable driver override */
  96                 spi->driver_override = NULL;
  97                 kfree(driver_override);
  98         }
  99         device_unlock(dev);
 100         kfree(old);
 101
 102         return count;
 103 }
 104
 105 static ssize_t driver_override_show(struct device *dev,
 106                                     struct device_attribute *a, char *buf)
 107 {
 108         const struct spi_device *spi = to_spi_device(dev);
 109         ssize_t len;
 110
 111         device_lock(dev);
 112         len = snprintf(buf, PAGE_SIZE, "%s\n", spi->driver_override ? : "");
 113         device_unlock(dev);
 114         return len;
 115 }
 116 static DEVICE_ATTR_RW(driver_override);
 117
 118 #define SPI_STATISTICS_ATTRS(field, file)                               \
 119 static ssize_t spi_controller_##field##_show(struct device *dev,        \
 120                                              struct device_attribute *attr, \
 121                                              char *buf)                 \
 122 {                                                                       \
 123         struct spi_controller *ctlr = container_of(dev,                 \
 124                                          struct spi_controller, dev);   \
 125         return spi_statistics_##field##_show(&ctlr->statistics, buf);   \
 126 }                                                                       \
 127 static struct device_attribute dev_attr_spi_controller_##field = {      \
 128         .attr = { .name = file, .mode = 0444 },                         \
 129         .show = spi_controller_##field##_show,                          \
 130 };                                                                      \
 131 static ssize_t spi_device_##field##_show(struct device *dev,            \
 132                                          struct device_attribute *attr, \
 133                                         char *buf)                      \
 134 {                                                                       \
 135         struct spi_device *spi = to_spi_device(dev);                    \
 136         return spi_statistics_##field##_show(&spi->statistics, buf);    \
 137 }                                                                       \
 138 static struct device_attribute dev_attr_spi_device_##field = {          \
 139         .attr = { .name = file, .mode = 0444 },                         \
 140         .show = spi_device_##field##_show,                              \
 141 }
 142
 143 #define SPI_STATISTICS_SHOW_NAME(name, file, field, format_string)      \
 144 static ssize_t spi_statistics_##name##_show(struct spi_statistics *stat, \
 145                                             char *buf)                  \
 146 {                                                                       \
 147         unsigned long flags;                                            \
 148         ssize_t len;                                                    \
 149         spin_lock_irqsave(&stat->lock, flags);                          \
 150         len = sprintf(buf, format_string, stat->field);                 \
 151         spin_unlock_irqrestore(&stat->lock, flags);                     \
 152         return len;                                                     \
 153 }                                                                       \
 154 SPI_STATISTICS_ATTRS(name, file)
 155
 156 #define SPI_STATISTICS_SHOW(field, format_string)                       \
 157         SPI_STATISTICS_SHOW_NAME(field, __stringify(field),             \
 158                                  field, format_string)
 159
 160 SPI_STATISTICS_SHOW(messages, "%lu");
 161 SPI_STATISTICS_SHOW(transfers, "%lu");
 162 SPI_STATISTICS_SHOW(errors, "%lu");
 163 SPI_STATISTICS_SHOW(timedout, "%lu");
 164
 165 SPI_STATISTICS_SHOW(spi_sync, "%lu");
 166 SPI_STATISTICS_SHOW(spi_sync_immediate, "%lu");
 167 SPI_STATISTICS_SHOW(spi_async, "%lu");
 168
 169 SPI_STATISTICS_SHOW(bytes, "%llu");
 170 SPI_STATISTICS_SHOW(bytes_rx, "%llu");
 171 SPI_STATISTICS_SHOW(bytes_tx, "%llu");
 172
 173 #define SPI_STATISTICS_TRANSFER_BYTES_HISTO(index, number)              \
 174         SPI_STATISTICS_SHOW_NAME(transfer_bytes_histo##index,           \
 175                                  "transfer_bytes_histo_" number,        \
 176                                  transfer_bytes_histo[index],  "%lu")
 177 SPI_STATISTICS_TRANSFER_BYTES_HISTO(0,  "0-1");
 178 SPI_STATISTICS_TRANSFER_BYTES_HISTO(1,  "2-3");
 179 SPI_STATISTICS_TRANSFER_BYTES_HISTO(2,  "4-7");
 180 SPI_STATISTICS_TRANSFER_BYTES_HISTO(3,  "8-15");
 181 SPI_STATISTICS_TRANSFER_BYTES_HISTO(4,  "16-31");
 182 SPI_STATISTICS_TRANSFER_BYTES_HISTO(5,  "32-63");
 183 SPI_STATISTICS_TRANSFER_BYTES_HISTO(6,  "64-127");
 184 SPI_STATISTICS_TRANSFER_BYTES_HISTO(7,  "128-255");
 185 SPI_STATISTICS_TRANSFER_BYTES_HISTO(8,  "256-511");
 186 SPI_STATISTICS_TRANSFER_BYTES_HISTO(9,  "512-1023");
 187 SPI_STATISTICS_TRANSFER_BYTES_HISTO(10, "1024-2047");
 188 SPI_STATISTICS_TRANSFER_BYTES_HISTO(11, "2048-4095");
 189 SPI_STATISTICS_TRANSFER_BYTES_HISTO(12, "4096-8191");
 190 SPI_STATISTICS_TRANSFER_BYTES_HISTO(13, "8192-16383");
 191 SPI_STATISTICS_TRANSFER_BYTES_HISTO(14, "16384-32767");
 192 SPI_STATISTICS_TRANSFER_BYTES_HISTO(15, "32768-65535");
 193 SPI_STATISTICS_TRANSFER_BYTES_HISTO(16, "65536+");
 194
 195 SPI_STATISTICS_SHOW(transfers_split_maxsize, "%lu");
 196
 197 static struct attribute *spi_dev_attrs[] = {
 198         &dev_attr_modalias.attr,
 199         &dev_attr_driver_override.attr,
 200         NULL,
 201 };
 202
 203 static const struct attribute_group spi_dev_group = {
 204         .attrs  = spi_dev_attrs,
 205 };
 206
 207 static struct attribute *spi_device_statistics_attrs[] = {
 208         &dev_attr_spi_device_messages.attr,
 209         &dev_attr_spi_device_transfers.attr,
 210         &dev_attr_spi_device_errors.attr,
 211         &dev_attr_spi_device_timedout.attr,
 212         &dev_attr_spi_device_spi_sync.attr,
 213         &dev_attr_spi_device_spi_sync_immediate.attr,
 214         &dev_attr_spi_device_spi_async.attr,
 215         &dev_attr_spi_device_bytes.attr,
 216         &dev_attr_spi_device_bytes_rx.attr,
 217         &dev_attr_spi_device_bytes_tx.attr,
 218         &dev_attr_spi_device_transfer_bytes_histo0.attr,
 219         &dev_attr_spi_device_transfer_bytes_histo1.attr,
 220         &dev_attr_spi_device_transfer_bytes_histo2.attr,
 221         &dev_attr_spi_device_transfer_bytes_histo3.attr,
 222         &dev_attr_spi_device_transfer_bytes_histo4.attr,
 223         &dev_attr_spi_device_transfer_bytes_histo5.attr,
 224         &dev_attr_spi_device_transfer_bytes_histo6.attr,
 225         &dev_attr_spi_device_transfer_bytes_histo7.attr,
 226         &dev_attr_spi_device_transfer_bytes_histo8.attr,
 227         &dev_attr_spi_device_transfer_bytes_histo9.attr,
 228         &dev_attr_spi_device_transfer_bytes_histo10.attr,
 229         &dev_attr_spi_device_transfer_bytes_histo11.attr,
 230         &dev_attr_spi_device_transfer_bytes_histo12.attr,
 231         &dev_attr_spi_device_transfer_bytes_histo13.attr,
 232         &dev_attr_spi_device_transfer_bytes_histo14.attr,
 233         &dev_attr_spi_device_transfer_bytes_histo15.attr,
 234         &dev_attr_spi_device_transfer_bytes_histo16.attr,
 235         &dev_attr_spi_device_transfers_split_maxsize.attr,
 236         NULL,
 237 };
 238
 239 static const struct attribute_group spi_device_statistics_group = {
 240         .name  = "statistics",
 241         .attrs  = spi_device_statistics_attrs,
 242 };
 243
 244 static const struct attribute_group *spi_dev_groups[] = {
 245         &spi_dev_group,
 246         &spi_device_statistics_group,
 247         NULL,
 248 };
 249
 250 static struct attribute *spi_controller_statistics_attrs[] = {
 251         &dev_attr_spi_controller_messages.attr,
 252         &dev_attr_spi_controller_transfers.attr,
 253         &dev_attr_spi_controller_errors.attr,
 254         &dev_attr_spi_controller_timedout.attr,
 255         &dev_attr_spi_controller_spi_sync.attr,
 256         &dev_attr_spi_controller_spi_sync_immediate.attr,
 257         &dev_attr_spi_controller_spi_async.attr,
 258         &dev_attr_spi_controller_bytes.attr,
 259         &dev_attr_spi_controller_bytes_rx.attr,
 260         &dev_attr_spi_controller_bytes_tx.attr,
 261         &dev_attr_spi_controller_transfer_bytes_histo0.attr,
 262         &dev_attr_spi_controller_transfer_bytes_histo1.attr,
 263         &dev_attr_spi_controller_transfer_bytes_histo2.attr,
 264         &dev_attr_spi_controller_transfer_bytes_histo3.attr,
 265         &dev_attr_spi_controller_transfer_bytes_histo4.attr,
 266         &dev_attr_spi_controller_transfer_bytes_histo5.attr,
 267         &dev_attr_spi_controller_transfer_bytes_histo6.attr,
 268         &dev_attr_spi_controller_transfer_bytes_histo7.attr,
 269         &dev_attr_spi_controller_transfer_bytes_histo8.attr,
 270         &dev_attr_spi_controller_transfer_bytes_histo9.attr,
 271         &dev_attr_spi_controller_transfer_bytes_histo10.attr,
 272         &dev_attr_spi_controller_transfer_bytes_histo11.attr,
 273         &dev_attr_spi_controller_transfer_bytes_histo12.attr,
 274         &dev_attr_spi_controller_transfer_bytes_histo13.attr,
 275         &dev_attr_spi_controller_transfer_bytes_histo14.attr,
 276         &dev_attr_spi_controller_transfer_bytes_histo15.attr,
 277         &dev_attr_spi_controller_transfer_bytes_histo16.attr,
 278         &dev_attr_spi_controller_transfers_split_maxsize.attr,
 279         NULL,
 280 };
 281
 282 static const struct attribute_group spi_controller_statistics_group = {
 283         .name  = "statistics",
 284         .attrs  = spi_controller_statistics_attrs,
 285 };
 286
 287 static const struct attribute_group *spi_master_groups[] = {
 288         &spi_controller_statistics_group,
 289         NULL,
 290 };
 291
 292 void spi_statistics_add_transfer_stats(struct spi_statistics *stats,
 293                                        struct spi_transfer *xfer,
 294                                        struct spi_controller *ctlr)
 295 {
 296         unsigned long flags;
 297         int l2len = min(fls(xfer->len), SPI_STATISTICS_HISTO_SIZE) - 1;
 298
 299         if (l2len < 0)
 300                 l2len = 0;
 301
 302         spin_lock_irqsave(&stats->lock, flags);
 303
 304         stats->transfers++;
 305         stats->transfer_bytes_histo[l2len]++;
 306
 307         stats->bytes += xfer->len;
 308         if ((xfer->tx_buf) &&
 309             (xfer->tx_buf != ctlr->dummy_tx))
 310                 stats->bytes_tx += xfer->len;
 311         if ((xfer->rx_buf) &&
 312             (xfer->rx_buf != ctlr->dummy_rx))
 313                 stats->bytes_rx += xfer->len;
 314
 315         spin_unlock_irqrestore(&stats->lock, flags);
 316 }
 317 EXPORT_SYMBOL_GPL(spi_statistics_add_transfer_stats);
 318
 319 /* modalias support makes "modprobe $MODALIAS" new-style hotplug work,
 320  * and the sysfs version makes coldplug work too.
 321  */
 322
 323 static const struct spi_device_id *spi_match_id(const struct spi_device_id *id,
 324                                                 const struct spi_device *sdev)
 325 {
 326         while (id->name[0]) {
 327                 if (!strcmp(sdev->modalias, id->name))
 328                         return id;
 329                 id++;
 330         }
 331         return NULL;
 332 }
 333
 334 const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev)
 335 {
 336         const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver);
 337
 338         return spi_match_id(sdrv->id_table, sdev);
 339 }
 340 EXPORT_SYMBOL_GPL(spi_get_device_id);
 341
 342 static int spi_match_device(struct device *dev, struct device_driver *drv)
 343 {
 344         const struct spi_device *spi = to_spi_device(dev);
 345         const struct spi_driver *sdrv = to_spi_driver(drv);
 346
 347         /* Check override first, and if set, only use the named driver */
 348         if (spi->driver_override)
 349                 return strcmp(spi->driver_override, drv->name) == 0;
 350
 351         /* Attempt an OF style match */
 352         if (of_driver_match_device(dev, drv))
 353                 return 1;
 354
 355         /* Then try ACPI */
 356         if (acpi_driver_match_device(dev, drv))
 357                 return 1;
 358
 359         if (sdrv->id_table)
 360                 return !!spi_match_id(sdrv->id_table, spi);
 361
 362         return strcmp(spi->modalias, drv->name) == 0;
 363 }
 364
 365 static int spi_uevent(struct device *dev, struct kobj_uevent_env *env)
 366 {
 367         const struct spi_device         *spi = to_spi_device(dev);
 368         int rc;
 369
 370         rc = acpi_device_uevent_modalias(dev, env);
 371         if (rc != -ENODEV)
 372                 return rc;
 373
 374         return add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias);
 375 }
 376
 377 struct bus_type spi_bus_type = {
 378         .name           = "spi",
 379         .dev_groups     = spi_dev_groups,
 380         .match          = spi_match_device,
 381         .uevent         = spi_uevent,
 382 };
 383 EXPORT_SYMBOL_GPL(spi_bus_type);
 384
 385
 386 static int spi_drv_probe(struct device *dev)
 387 {
 388         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
 389         struct spi_device               *spi = to_spi_device(dev);
 390         int ret;
 391
 392         ret = of_clk_set_defaults(dev->of_node, false);
 393         if (ret)
 394                 return ret;
 395
 396         if (dev->of_node) {
 397                 spi->irq = of_irq_get(dev->of_node, 0);
 398                 if (spi->irq == -EPROBE_DEFER)
 399                         return -EPROBE_DEFER;
 400                 if (spi->irq < 0)
 401                         spi->irq = 0;
 402         }
 403
 404         ret = dev_pm_domain_attach(dev, true);
 405         if (ret)
 406                 return ret;
 407
 408         ret = sdrv->probe(spi);
 409         if (ret)
 410                 dev_pm_domain_detach(dev, true);
 411
 412         return ret;
 413 }
 414
 415 static int spi_drv_remove(struct device *dev)
 416 {
 417         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
 418         int ret;
 419
 420         ret = sdrv->remove(to_spi_device(dev));
 421         dev_pm_domain_detach(dev, true);
 422
 423         return ret;
 424 }
 425
 426 static void spi_drv_shutdown(struct device *dev)
 427 {
 428         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
 429
 430         sdrv->shutdown(to_spi_device(dev));
 431 }
 432
 433 /**
 434  * __spi_register_driver - register a SPI driver
 435  * @owner: owner module of the driver to register
 436  * @sdrv: the driver to register
 437  * Context: can sleep
 438  *
 439  * Return: zero on success, else a negative error code.
 440  */
 441 int __spi_register_driver(struct module *owner, struct spi_driver *sdrv)
 442 {
 443         sdrv->driver.owner = owner;
 444         sdrv->driver.bus = &spi_bus_type;
 445         if (sdrv->probe)
 446                 sdrv->driver.probe = spi_drv_probe;
 447         if (sdrv->remove)
 448                 sdrv->driver.remove = spi_drv_remove;
 449         if (sdrv->shutdown)
 450                 sdrv->driver.shutdown = spi_drv_shutdown;
 451         return driver_register(&sdrv->driver);
 452 }
 453 EXPORT_SYMBOL_GPL(__spi_register_driver);
 454
 455 /*-------------------------------------------------------------------------*/
 456
 457 /* SPI devices should normally not be created by SPI device drivers; that
 458  * would make them board-specific.  Similarly with SPI controller drivers.
 459  * Device registration normally goes into like arch/.../mach.../board-YYY.c
 460  * with other readonly (flashable) information about mainboard devices.
 461  */
 462
 463 struct boardinfo {
 464         struct list_head        list;
 465         struct spi_board_info   board_info;
 466 };
 467
 468 static LIST_HEAD(board_list);
 469 static LIST_HEAD(spi_controller_list);
 470
 471 /*
 472  * Used to protect add/del opertion for board_info list and
 473  * spi_controller list, and their matching process
 474  * also used to protect object of type struct idr
 475  */
 476 static DEFINE_MUTEX(board_lock);
 477
 478 /**
 479  * spi_alloc_device - Allocate a new SPI device
 480  * @ctlr: Controller to which device is connected
 481  * Context: can sleep
 482  *
 483  * Allows a driver to allocate and initialize a spi_device without
 484  * registering it immediately.  This allows a driver to directly
 485  * fill the spi_device with device parameters before calling
 486  * spi_add_device() on it.
 487  *
 488  * Caller is responsible to call spi_add_device() on the returned
 489  * spi_device structure to add it to the SPI controller.  If the caller
 490  * needs to discard the spi_device without adding it, then it should
 491  * call spi_dev_put() on it.
 492  *
 493  * Return: a pointer to the new device, or NULL.
 494  */
 495 struct spi_device *spi_alloc_device(struct spi_controller *ctlr)
 496 {
 497         struct spi_device       *spi;
 498
 499         if (!spi_controller_get(ctlr))
 500                 return NULL;
 501
 502         spi = kzalloc(sizeof(*spi), GFP_KERNEL);
 503         if (!spi) {
 504                 spi_controller_put(ctlr);
 505                 return NULL;
 506         }
 507
 508         spi->master = spi->controller = ctlr;
 509         spi->dev.parent = &ctlr->dev;
 510         spi->dev.bus = &spi_bus_type;
 511         spi->dev.release = spidev_release;
 512         spi->cs_gpio = -ENOENT;
 513
 514         spin_lock_init(&spi->statistics.lock);
 515
 516         device_initialize(&spi->dev);
 517         return spi;
 518 }
 519 EXPORT_SYMBOL_GPL(spi_alloc_device);
 520
 521 static void spi_dev_set_name(struct spi_device *spi)
 522 {
 523         struct acpi_device *adev = ACPI_COMPANION(&spi->dev);
 524
 525         if (adev) {
 526                 dev_set_name(&spi->dev, "spi-%s", acpi_dev_name(adev));
 527                 return;
 528         }
 529
 530         dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->controller->dev),
 531                      spi->chip_select);
 532 }
 533
 534 static int spi_dev_check(struct device *dev, void *data)
 535 {
 536         struct spi_device *spi = to_spi_device(dev);
 537         struct spi_device *new_spi = data;
 538
 539         if (spi->controller == new_spi->controller &&
 540             spi->chip_select == new_spi->chip_select)
 541                 return -EBUSY;
 542         return 0;
 543 }
 544
 545 /**
 546  * spi_add_device - Add spi_device allocated with spi_alloc_device
 547  * @spi: spi_device to register
 548  *
 549  * Companion function to spi_alloc_device.  Devices allocated with
 550  * spi_alloc_device can be added onto the spi bus with this function.
 551  *
 552  * Return: 0 on success; negative errno on failure
 553  */
 554 int spi_add_device(struct spi_device *spi)
 555 {
 556         static DEFINE_MUTEX(spi_add_lock);
 557         struct spi_controller *ctlr = spi->controller;
 558         struct device *dev = ctlr->dev.parent;
 559         int status;
 560
 561         /* Chipselects are numbered 0..max; validate. */
 562         if (spi->chip_select >= ctlr->num_chipselect) {
 563                 dev_err(dev, "cs%d >= max %d\n", spi->chip_select,
 564                         ctlr->num_chipselect);
 565                 return -EINVAL;
 566         }
 567
 568         /* Set the bus ID string */
 569         spi_dev_set_name(spi);
 570
 571         /* We need to make sure there's no other device with this
 572          * chipselect **BEFORE** we call setup(), else we'll trash
 573          * its configuration.  Lock against concurrent add() calls.
 574          */
 575         mutex_lock(&spi_add_lock);
 576
 577         status = bus_for_each_dev(&spi_bus_type, NULL, spi, spi_dev_check);
 578         if (status) {
 579                 dev_err(dev, "chipselect %d already in use\n",
 580                                 spi->chip_select);
 581                 goto done;
 582         }
 583
 584         /* Descriptors take precedence */
 585         if (ctlr->cs_gpiods)
 586                 spi->cs_gpiod = ctlr->cs_gpiods[spi->chip_select];
 587         else if (ctlr->cs_gpios)
 588                 spi->cs_gpio = ctlr->cs_gpios[spi->chip_select];
 589
 590         /* Drivers may modify this initial i/o setup, but will
 591          * normally rely on the device being setup.  Devices
 592          * using SPI_CS_HIGH can't coexist well otherwise...
 593          */
 594         status = spi_setup(spi);
 595         if (status < 0) {
 596                 dev_err(dev, "can't setup %s, status %d\n",
 597                                 dev_name(&spi->dev), status);
 598                 goto done;
 599         }
 600
 601         /* Device may be bound to an active driver when this returns */
 602         status = device_add(&spi->dev);
 603         if (status < 0)
 604                 dev_err(dev, "can't add %s, status %d\n",
 605                                 dev_name(&spi->dev), status);
 606         else
 607                 dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
 608
 609 done:
 610         mutex_unlock(&spi_add_lock);
 611         return status;
 612 }
 613 EXPORT_SYMBOL_GPL(spi_add_device);
 614
 615 /**
 616  * spi_new_device - instantiate one new SPI device
 617  * @ctlr: Controller to which device is connected
 618  * @chip: Describes the SPI device
 619  * Context: can sleep
 620  *
 621  * On typical mainboards, this is purely internal; and it's not needed
 622  * after board init creates the hard-wired devices.  Some development
 623  * platforms may not be able to use spi_register_board_info though, and
 624  * this is exported so that for example a USB or parport based adapter
 625  * driver could add devices (which it would learn about out-of-band).
 626  *
 627  * Return: the new device, or NULL.
 628  */
 629 struct spi_device *spi_new_device(struct spi_controller *ctlr,
 630                                   struct spi_board_info *chip)
 631 {
 632         struct spi_device       *proxy;
 633         int                     status;
 634
 635         /* NOTE:  caller did any chip->bus_num checks necessary.
 636          *
 637          * Also, unless we change the return value convention to use
 638          * error-or-pointer (not NULL-or-pointer), troubleshootability
 639          * suggests syslogged diagnostics are best here (ugh).
 640          */
 641
 642         proxy = spi_alloc_device(ctlr);
 643         if (!proxy)
 644                 return NULL;
 645
 646         WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
 647
 648         proxy->chip_select = chip->chip_select;
 649         proxy->max_speed_hz = chip->max_speed_hz;
 650         proxy->mode = chip->mode;
 651         proxy->irq = chip->irq;
 652         strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
 653         proxy->dev.platform_data = (void *) chip->platform_data;
 654         proxy->controller_data = chip->controller_data;
 655         proxy->controller_state = NULL;
 656
 657         if (chip->properties) {
 658                 status = device_add_properties(&proxy->dev, chip->properties);
 659                 if (status) {
 660                         dev_err(&ctlr->dev,
 661                                 "failed to add properties to '%s': %d\n",
 662                                 chip->modalias, status);
 663                         goto err_dev_put;
 664                 }
 665         }
 666
 667         status = spi_add_device(proxy);
 668         if (status < 0)
 669                 goto err_remove_props;
 670
 671         return proxy;
 672
 673 err_remove_props:
 674         if (chip->properties)
 675                 device_remove_properties(&proxy->dev);
 676 err_dev_put:
 677         spi_dev_put(proxy);
 678         return NULL;
 679 }
 680 EXPORT_SYMBOL_GPL(spi_new_device);
 681
 682 /**
 683  * spi_unregister_device - unregister a single SPI device
 684  * @spi: spi_device to unregister
 685  *
 686  * Start making the passed SPI device vanish. Normally this would be handled
 687  * by spi_unregister_controller().
 688  */
 689 void spi_unregister_device(struct spi_device *spi)
 690 {
 691         if (!spi)
 692                 return;
 693
 694         if (spi->dev.of_node) {
 695                 of_node_clear_flag(spi->dev.of_node, OF_POPULATED);
 696                 of_node_put(spi->dev.of_node);
 697         }
 698         if (ACPI_COMPANION(&spi->dev))
 699                 acpi_device_clear_enumerated(ACPI_COMPANION(&spi->dev));
 700         device_unregister(&spi->dev);
 701 }
 702 EXPORT_SYMBOL_GPL(spi_unregister_device);
 703
 704 static void spi_match_controller_to_boardinfo(struct spi_controller *ctlr,
 705                                               struct spi_board_info *bi)
 706 {
 707         struct spi_device *dev;
 708
 709         if (ctlr->bus_num != bi->bus_num)
 710                 return;
 711
 712         dev = spi_new_device(ctlr, bi);
 713         if (!dev)
 714                 dev_err(ctlr->dev.parent, "can't create new device for %s\n",
 715                         bi->modalias);
 716 }
 717
 718 /**
 719  * spi_register_board_info - register SPI devices for a given board
 720  * @info: array of chip descriptors
 721  * @n: how many descriptors are provided
 722  * Context: can sleep
 723  *
 724  * Board-specific early init code calls this (probably during arch_initcall)
 725  * with segments of the SPI device table.  Any device nodes are created later,
 726  * after the relevant parent SPI controller (bus_num) is defined.  We keep
 727  * this table of devices forever, so that reloading a controller driver will
 728  * not make Linux forget about these hard-wired devices.
 729  *
 730  * Other code can also call this, e.g. a particular add-on board might provide
 731  * SPI devices through its expansion connector, so code initializing that board
 732  * would naturally declare its SPI devices.
 733  *
 734  * The board info passed can safely be __initdata ... but be careful of
 735  * any embedded pointers (platform_data, etc), they're copied as-is.
 736  * Device properties are deep-copied though.
 737  *
 738  * Return: zero on success, else a negative error code.
 739  */
 740 int spi_register_board_info(struct spi_board_info const *info, unsigned n)
 741 {
 742         struct boardinfo *bi;
 743         int i;
 744
 745         if (!n)
 746                 return 0;
 747
 748         bi = kcalloc(n, sizeof(*bi), GFP_KERNEL);
 749         if (!bi)
 750                 return -ENOMEM;
 751
 752         for (i = 0; i < n; i++, bi++, info++) {
 753                 struct spi_controller *ctlr;
 754
 755                 memcpy(&bi->board_info, info, sizeof(*info));
 756                 if (info->properties) {
 757                         bi->board_info.properties =
 758                                         property_entries_dup(info->properties);
 759                         if (IS_ERR(bi->board_info.properties))
 760                                 return PTR_ERR(bi->board_info.properties);
 761                 }
 762
 763                 mutex_lock(&board_lock);
 764                 list_add_tail(&bi->list, &board_list);
 765                 list_for_each_entry(ctlr, &spi_controller_list, list)
 766                         spi_match_controller_to_boardinfo(ctlr,
 767                                                           &bi->board_info);
 768                 mutex_unlock(&board_lock);
 769         }
 770
 771         return 0;
 772 }
 773
 774 /*-------------------------------------------------------------------------*/
 775
 776 static void spi_set_cs(struct spi_device *spi, bool enable)
 777 {
 778         if (spi->mode & SPI_CS_HIGH)
 779                 enable = !enable;
 780
 781         if (spi->cs_gpiod || gpio_is_valid(spi->cs_gpio)) {
 782                 /*
 783                  * Honour the SPI_NO_CS flag and invert the enable line, as
 784                  * active low is default for SPI. Execution paths that handle
 785                  * polarity inversion in gpiolib (such as device tree) will
 786                  * enforce active high using the SPI_CS_HIGH resulting in a
 787                  * double inversion through the code above.
 788                  */
 789                 if (!(spi->mode & SPI_NO_CS)) {
 790                         if (spi->cs_gpiod)
 791                                 gpiod_set_value_cansleep(spi->cs_gpiod,
 792                                                          !enable);
 793                         else
 794                                 gpio_set_value_cansleep(spi->cs_gpio, !enable);
 795                 }
 796                 /* Some SPI masters need both GPIO CS & slave_select */
 797                 if ((spi->controller->flags & SPI_MASTER_GPIO_SS) &&
 798                     spi->controller->set_cs)
 799                         spi->controller->set_cs(spi, !enable);
 800         } else if (spi->controller->set_cs) {
 801                 spi->controller->set_cs(spi, !enable);
 802         }
 803 }
 804
 805 #ifdef CONFIG_HAS_DMA
 806 int spi_map_buf(struct spi_controller *ctlr, struct device *dev,
 807                 struct sg_table *sgt, void *buf, size_t len,
 808                 enum dma_data_direction dir)
 809 {
 810         const bool vmalloced_buf = is_vmalloc_addr(buf);
 811         unsigned int max_seg_size = dma_get_max_seg_size(dev);
 812 #ifdef CONFIG_HIGHMEM
 813         const bool kmap_buf = ((unsigned long)buf >= PKMAP_BASE &&
 814                                 (unsigned long)buf < (PKMAP_BASE +
 815                                         (LAST_PKMAP * PAGE_SIZE)));
 816 #else
 817         const bool kmap_buf = false;
 818 #endif
 819         int desc_len;
 820         int sgs;
 821         struct page *vm_page;
 822         struct scatterlist *sg;
 823         void *sg_buf;
 824         size_t min;
 825         int i, ret;
 826
 827         if (vmalloced_buf || kmap_buf) {
 828                 desc_len = min_t(int, max_seg_size, PAGE_SIZE);
 829                 sgs = DIV_ROUND_UP(len + offset_in_page(buf), desc_len);
 830         } else if (virt_addr_valid(buf)) {
 831                 desc_len = min_t(int, max_seg_size, ctlr->max_dma_len);
 832                 sgs = DIV_ROUND_UP(len, desc_len);
 833         } else {
 834                 return -EINVAL;
 835         }
 836
 837         ret = sg_alloc_table(sgt, sgs, GFP_KERNEL);
 838         if (ret != 0)
 839                 return ret;
 840
 841         sg = &sgt->sgl[0];
 842         for (i = 0; i < sgs; i++) {
 843
 844                 if (vmalloced_buf || kmap_buf) {
 845                         /*
 846                          * Next scatterlist entry size is the minimum between
 847                          * the desc_len and the remaining buffer length that
 848                          * fits in a page.
 849                          */
 850                         min = min_t(size_t, desc_len,
 851                                     min_t(size_t, len,
 852                                           PAGE_SIZE - offset_in_page(buf)));
 853                         if (vmalloced_buf)
 854                                 vm_page = vmalloc_to_page(buf);
 855                         else
 856                                 vm_page = kmap_to_page(buf);
 857                         if (!vm_page) {
 858                                 sg_free_table(sgt);
 859                                 return -ENOMEM;
 860                         }
 861                         sg_set_page(sg, vm_page,
 862                                     min, offset_in_page(buf));
 863                 } else {
 864                         min = min_t(size_t, len, desc_len);
 865                         sg_buf = buf;
 866                         sg_set_buf(sg, sg_buf, min);
 867                 }
 868
 869                 buf += min;
 870                 len -= min;
 871                 sg = sg_next(sg);
 872         }
 873
 874         ret = dma_map_sg(dev, sgt->sgl, sgt->nents, dir);
 875         if (!ret)
 876                 ret = -ENOMEM;
 877         if (ret < 0) {
 878                 sg_free_table(sgt);
 879                 return ret;
 880         }
 881
 882         sgt->nents = ret;
 883
 884         return 0;
 885 }
 886
 887 void spi_unmap_buf(struct spi_controller *ctlr, struct device *dev,
 888                    struct sg_table *sgt, enum dma_data_direction dir)
 889 {
 890         if (sgt->orig_nents) {
 891                 dma_unmap_sg(dev, sgt->sgl, sgt->orig_nents, dir);
 892                 sg_free_table(sgt);
 893         }
 894 }
 895
 896 static int __spi_map_msg(struct spi_controller *ctlr, struct spi_message *msg)
 897 {
 898         struct device *tx_dev, *rx_dev;
 899         struct spi_transfer *xfer;
 900         int ret;
 901
 902         if (!ctlr->can_dma)
 903                 return 0;
 904
 905         if (ctlr->dma_tx)
 906                 tx_dev = ctlr->dma_tx->device->dev;
 907         else
 908                 tx_dev = ctlr->dev.parent;
 909
 910         if (ctlr->dma_rx)
 911                 rx_dev = ctlr->dma_rx->device->dev;
 912         else
 913                 rx_dev = ctlr->dev.parent;
 914
 915         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 916                 if (!ctlr->can_dma(ctlr, msg->spi, xfer))
 917                         continue;
 918
 919                 if (xfer->tx_buf != NULL) {
 920                         ret = spi_map_buf(ctlr, tx_dev, &xfer->tx_sg,
 921                                           (void *)xfer->tx_buf, xfer->len,
 922                                           DMA_TO_DEVICE);
 923                         if (ret != 0)
 924                                 return ret;
 925                 }
 926
 927                 if (xfer->rx_buf != NULL) {
 928                         ret = spi_map_buf(ctlr, rx_dev, &xfer->rx_sg,
 929                                           xfer->rx_buf, xfer->len,
 930                                           DMA_FROM_DEVICE);
 931                         if (ret != 0) {
 932                                 spi_unmap_buf(ctlr, tx_dev, &xfer->tx_sg,
 933                                               DMA_TO_DEVICE);
 934                                 return ret;
 935                         }
 936                 }
 937         }
 938
 939         ctlr->cur_msg_mapped = true;
 940
 941         return 0;
 942 }
 943
 944 static int __spi_unmap_msg(struct spi_controller *ctlr, struct spi_message *msg)
 945 {
 946         struct spi_transfer *xfer;
 947         struct device *tx_dev, *rx_dev;
 948
 949         if (!ctlr->cur_msg_mapped || !ctlr->can_dma)
 950                 return 0;
 951
 952         if (ctlr->dma_tx)
 953                 tx_dev = ctlr->dma_tx->device->dev;
 954         else
 955                 tx_dev = ctlr->dev.parent;
 956
 957         if (ctlr->dma_rx)
 958                 rx_dev = ctlr->dma_rx->device->dev;
 959         else
 960                 rx_dev = ctlr->dev.parent;
 961
 962         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 963                 if (!ctlr->can_dma(ctlr, msg->spi, xfer))
 964                         continue;
 965
 966                 spi_unmap_buf(ctlr, rx_dev, &xfer->rx_sg, DMA_FROM_DEVICE);
 967                 spi_unmap_buf(ctlr, tx_dev, &xfer->tx_sg, DMA_TO_DEVICE);
 968         }
 969
 970         return 0;
 971 }
 972 #else /* !CONFIG_HAS_DMA */
 973 static inline int __spi_map_msg(struct spi_controller *ctlr,
 974                                 struct spi_message *msg)
 975 {
 976         return 0;
 977 }
 978
 979 static inline int __spi_unmap_msg(struct spi_controller *ctlr,
 980                                   struct spi_message *msg)
 981 {
 982         return 0;
 983 }
 984 #endif /* !CONFIG_HAS_DMA */
 985
 986 static inline int spi_unmap_msg(struct spi_controller *ctlr,
 987                                 struct spi_message *msg)
 988 {
 989         struct spi_transfer *xfer;
 990
 991         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 992                 /*
 993                  * Restore the original value of tx_buf or rx_buf if they are
 994                  * NULL.
 995                  */
 996                 if (xfer->tx_buf == ctlr->dummy_tx)
 997                         xfer->tx_buf = NULL;
 998                 if (xfer->rx_buf == ctlr->dummy_rx)
 999                         xfer->rx_buf = NULL;
1000         }
1001
1002         return __spi_unmap_msg(ctlr, msg);
1003 }
1004
1005 static int spi_map_msg(struct spi_controller *ctlr, struct spi_message *msg)
1006 {
1007         struct spi_transfer *xfer;
1008         void *tmp;
1009         unsigned int max_tx, max_rx;
1010
1011         if (ctlr->flags & (SPI_CONTROLLER_MUST_RX | SPI_CONTROLLER_MUST_TX)) {
1012                 max_tx = 0;
1013                 max_rx = 0;
1014
1015                 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1016                         if ((ctlr->flags & SPI_CONTROLLER_MUST_TX) &&
1017                             !xfer->tx_buf)
1018                                 max_tx = max(xfer->len, max_tx);
1019                         if ((ctlr->flags & SPI_CONTROLLER_MUST_RX) &&
1020                             !xfer->rx_buf)
1021                                 max_rx = max(xfer->len, max_rx);
1022                 }
1023
1024                 if (max_tx) {
1025                         tmp = krealloc(ctlr->dummy_tx, max_tx,
1026                                        GFP_KERNEL | GFP_DMA);
1027                         if (!tmp)
1028                                 return -ENOMEM;
1029                         ctlr->dummy_tx = tmp;
1030                         memset(tmp, 0, max_tx);
1031                 }
1032
1033                 if (max_rx) {
1034                         tmp = krealloc(ctlr->dummy_rx, max_rx,
1035                                        GFP_KERNEL | GFP_DMA);
1036                         if (!tmp)
1037                                 return -ENOMEM;
1038                         ctlr->dummy_rx = tmp;
1039                 }
1040
1041                 if (max_tx || max_rx) {
1042                         list_for_each_entry(xfer, &msg->transfers,
1043                                             transfer_list) {
1044                                 if (!xfer->len)
1045                                         continue;
1046                                 if (!xfer->tx_buf)
1047                                         xfer->tx_buf = ctlr->dummy_tx;
1048                                 if (!xfer->rx_buf)
1049                                         xfer->rx_buf = ctlr->dummy_rx;
1050                         }
1051                 }
1052         }
1053
1054         return __spi_map_msg(ctlr, msg);
1055 }
1056
1057 static int spi_transfer_wait(struct spi_controller *ctlr,
1058                              struct spi_message *msg,
1059                              struct spi_transfer *xfer)
1060 {
1061         struct spi_statistics *statm = &ctlr->statistics;
1062         struct spi_statistics *stats = &msg->spi->statistics;
1063         unsigned long long ms = 1;
1064
1065         if (spi_controller_is_slave(ctlr)) {
1066                 if (wait_for_completion_interruptible(&ctlr->xfer_completion)) {
1067                         dev_dbg(&msg->spi->dev, "SPI transfer interrupted\n");
1068                         return -EINTR;
1069                 }
1070         } else {
1071                 ms = 8LL * 1000LL * xfer->len;
1072                 do_div(ms, xfer->speed_hz);
1073                 ms += ms + 200; /* some tolerance */
1074
1075                 if (ms > UINT_MAX)
1076                         ms = UINT_MAX;
1077
1078                 ms = wait_for_completion_timeout(&ctlr->xfer_completion,
1079                                                  msecs_to_jiffies(ms));
1080
1081                 if (ms == 0) {
1082                         SPI_STATISTICS_INCREMENT_FIELD(statm, timedout);
1083                         SPI_STATISTICS_INCREMENT_FIELD(stats, timedout);
1084                         dev_err(&msg->spi->dev,
1085                                 "SPI transfer timed out\n");
1086                         return -ETIMEDOUT;
1087                 }
1088         }
1089
1090         return 0;
1091 }
1092
1093 static void _spi_transfer_delay_ns(u32 ns)
1094 {
1095         if (!ns)
1096                 return;
1097         if (ns <= 1000) {
1098                 ndelay(ns);
1099         } else {
1100                 u32 us = DIV_ROUND_UP(ns, 1000);
1101
1102                 if (us <= 10)
1103                         udelay(us);
1104                 else
1105                         usleep_range(us, us + DIV_ROUND_UP(us, 10));
1106         }
1107 }
1108
1109 static void _spi_transfer_cs_change_delay(struct spi_message *msg,
1110                                           struct spi_transfer *xfer)
1111 {
1112         u32 delay = xfer->cs_change_delay;
1113         u32 unit = xfer->cs_change_delay_unit;
1114         u32 hz;
1115
1116         /* return early on "fast" mode - for everything but USECS */
1117         if (!delay && unit != SPI_DELAY_UNIT_USECS)
1118                 return;
1119
1120         switch (unit) {
1121         case SPI_DELAY_UNIT_USECS:
1122                 /* for compatibility use default of 10us */
1123                 if (!delay)
1124                         delay = 10000;
1125                 else
1126                         delay *= 1000;
1127                 break;
1128         case SPI_DELAY_UNIT_NSECS: /* nothing to do here */
1129                 break;
1130         case SPI_DELAY_UNIT_SCK:
1131                 /* if there is no effective speed know, then approximate
1132                  * by underestimating with half the requested hz
1133                  */
1134                 hz = xfer->effective_speed_hz ?: xfer->speed_hz / 2;
1135                 delay *= DIV_ROUND_UP(1000000000, hz);
1136                 break;
1137         default:
1138                 dev_err_once(&msg->spi->dev,
1139                              "Use of unsupported delay unit %i, using default of 10us\n",
1140                              xfer->cs_change_delay_unit);
1141                 delay = 10000;
1142         }
1143         /* now sleep for the requested amount of time */
1144         _spi_transfer_delay_ns(delay);
1145 }
1146
1147 /*
1148  * spi_transfer_one_message - Default implementation of transfer_one_message()
1149  *
1150  * This is a standard implementation of transfer_one_message() for
1151  * drivers which implement a transfer_one() operation.  It provides
1152  * standard handling of delays and chip select management.
1153  */
1154 static int spi_transfer_one_message(struct spi_controller *ctlr,
1155                                     struct spi_message *msg)
1156 {
1157         struct spi_transfer *xfer;
1158         bool keep_cs = false;
1159         int ret = 0;
1160         struct spi_statistics *statm = &ctlr->statistics;
1161         struct spi_statistics *stats = &msg->spi->statistics;
1162
1163         spi_set_cs(msg->spi, true);
1164
1165         SPI_STATISTICS_INCREMENT_FIELD(statm, messages);
1166         SPI_STATISTICS_INCREMENT_FIELD(stats, messages);
1167
1168         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1169                 trace_spi_transfer_start(msg, xfer);
1170
1171                 spi_statistics_add_transfer_stats(statm, xfer, ctlr);
1172                 spi_statistics_add_transfer_stats(stats, xfer, ctlr);
1173
1174                 if (xfer->tx_buf || xfer->rx_buf) {
1175                         reinit_completion(&ctlr->xfer_completion);
1176
1177                         ret = ctlr->transfer_one(ctlr, msg->spi, xfer);
1178                         if (ret < 0) {
1179                                 SPI_STATISTICS_INCREMENT_FIELD(statm,
1180                                                                errors);
1181                                 SPI_STATISTICS_INCREMENT_FIELD(stats,
1182                                                                errors);
1183                                 dev_err(&msg->spi->dev,
1184                                         "SPI transfer failed: %d\n", ret);
1185                                 goto out;
1186                         }
1187
1188                         if (ret > 0) {
1189                                 ret = spi_transfer_wait(ctlr, msg, xfer);
1190                                 if (ret < 0)
1191                                         msg->status = ret;
1192                         }
1193                 } else {
1194                         if (xfer->len)
1195                                 dev_err(&msg->spi->dev,
1196                                         "Bufferless transfer has length %u\n",
1197                                         xfer->len);
1198                 }
1199
1200                 trace_spi_transfer_stop(msg, xfer);
1201
1202                 if (msg->status != -EINPROGRESS)
1203                         goto out;
1204
1205                 if (xfer->delay_usecs)
1206                         _spi_transfer_delay_ns(xfer->delay_usecs * 1000);
1207
1208                 if (xfer->cs_change) {
1209                         if (list_is_last(&xfer->transfer_list,
1210                                          &msg->transfers)) {
1211                                 keep_cs = true;
1212                         } else {
1213                                 spi_set_cs(msg->spi, false);
1214                                 _spi_transfer_cs_change_delay(msg, xfer);
1215                                 spi_set_cs(msg->spi, true);
1216                         }
1217                 }
1218
1219                 msg->actual_length += xfer->len;
1220         }
1221
1222 out:
1223         if (ret != 0 || !keep_cs)
1224                 spi_set_cs(msg->spi, false);
1225
1226         if (msg->status == -EINPROGRESS)
1227                 msg->status = ret;
1228
1229         if (msg->status && ctlr->handle_err)
1230                 ctlr->handle_err(ctlr, msg);
1231
1232         spi_res_release(ctlr, msg);
1233
1234         spi_finalize_current_message(ctlr);
1235
1236         return ret;
1237 }
1238
1239 /**
1240  * spi_finalize_current_transfer - report completion of a transfer
1241  * @ctlr: the controller reporting completion
1242  *
1243  * Called by SPI drivers using the core transfer_one_message()
1244  * implementation to notify it that the current interrupt driven
1245  * transfer has finished and the next one may be scheduled.
1246  */
1247 void spi_finalize_current_transfer(struct spi_controller *ctlr)
1248 {
1249         complete(&ctlr->xfer_completion);
1250 }
1251 EXPORT_SYMBOL_GPL(spi_finalize_current_transfer);
1252
1253 /**
1254  * __spi_pump_messages - function which processes spi message queue
1255  * @ctlr: controller to process queue for
1256  * @in_kthread: true if we are in the context of the message pump thread
1257  *
1258  * This function checks if there is any spi message in the queue that
1259  * needs processing and if so call out to the driver to initialize hardware
1260  * and transfer each message.
1261  *
1262  * Note that it is called both from the kthread itself and also from
1263  * inside spi_sync(); the queue extraction handling at the top of the
1264  * function should deal with this safely.
1265  */
1266 static void __spi_pump_messages(struct spi_controller *ctlr, bool in_kthread)
1267 {
1268         unsigned long flags;
1269         bool was_busy = false;
1270         int ret;
1271
1272         /* Lock queue */
1273         spin_lock_irqsave(&ctlr->queue_lock, flags);
1274
1275         /* Make sure we are not already running a message */
1276         if (ctlr->cur_msg) {
1277                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1278                 return;
1279         }
1280
1281         /* If another context is idling the device then defer */
1282         if (ctlr->idling) {
1283                 kthread_queue_work(&ctlr->kworker, &ctlr->pump_messages);
1284                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1285                 return;
1286         }
1287
1288         /* Check if the queue is idle */
1289         if (list_empty(&ctlr->queue) || !ctlr->running) {
1290                 if (!ctlr->busy) {
1291                         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1292                         return;
1293                 }
1294
1295                 /* Only do teardown in the thread */
1296                 if (!in_kthread) {
1297                         kthread_queue_work(&ctlr->kworker,
1298                                            &ctlr->pump_messages);
1299                         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1300                         return;
1301                 }
1302
1303                 ctlr->busy = false;
1304                 ctlr->idling = true;
1305                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1306
1307                 kfree(ctlr->dummy_rx);
1308                 ctlr->dummy_rx = NULL;
1309                 kfree(ctlr->dummy_tx);
1310                 ctlr->dummy_tx = NULL;
1311                 if (ctlr->unprepare_transfer_hardware &&
1312                     ctlr->unprepare_transfer_hardware(ctlr))
1313                         dev_err(&ctlr->dev,
1314                                 "failed to unprepare transfer hardware\n");
1315                 if (ctlr->auto_runtime_pm) {
1316                         pm_runtime_mark_last_busy(ctlr->dev.parent);
1317                         pm_runtime_put_autosuspend(ctlr->dev.parent);
1318                 }
1319                 trace_spi_controller_idle(ctlr);
1320
1321                 spin_lock_irqsave(&ctlr->queue_lock, flags);
1322                 ctlr->idling = false;
1323                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1324                 return;
1325         }
1326
1327         /* Extract head of queue */
1328         ctlr->cur_msg =
1329                 list_first_entry(&ctlr->queue, struct spi_message, queue);
1330
1331         list_del_init(&ctlr->cur_msg->queue);
1332         if (ctlr->busy)
1333                 was_busy = true;
1334         else
1335                 ctlr->busy = true;
1336         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1337
1338         mutex_lock(&ctlr->io_mutex);
1339
1340         if (!was_busy && ctlr->auto_runtime_pm) {
1341                 ret = pm_runtime_get_sync(ctlr->dev.parent);
1342                 if (ret < 0) {
1343                         pm_runtime_put_noidle(ctlr->dev.parent);
1344                         dev_err(&ctlr->dev, "Failed to power device: %d\n",
1345                                 ret);
1346                         mutex_unlock(&ctlr->io_mutex);
1347                         return;
1348                 }
1349         }
1350
1351         if (!was_busy)
1352                 trace_spi_controller_busy(ctlr);
1353
1354         if (!was_busy && ctlr->prepare_transfer_hardware) {
1355                 ret = ctlr->prepare_transfer_hardware(ctlr);
1356                 if (ret) {
1357                         dev_err(&ctlr->dev,
1358                                 "failed to prepare transfer hardware: %d\n",
1359                                 ret);
1360
1361                         if (ctlr->auto_runtime_pm)
1362                                 pm_runtime_put(ctlr->dev.parent);
1363
1364                         ctlr->cur_msg->status = ret;
1365                         spi_finalize_current_message(ctlr);
1366
1367                         mutex_unlock(&ctlr->io_mutex);
1368                         return;
1369                 }
1370         }
1371
1372         trace_spi_message_start(ctlr->cur_msg);
1373
1374         if (ctlr->prepare_message) {
1375                 ret = ctlr->prepare_message(ctlr, ctlr->cur_msg);
1376                 if (ret) {
1377                         dev_err(&ctlr->dev, "failed to prepare message: %d\n",
1378                                 ret);
1379                         ctlr->cur_msg->status = ret;
1380                         spi_finalize_current_message(ctlr);
1381                         goto out;
1382                 }
1383                 ctlr->cur_msg_prepared = true;
1384         }
1385
1386         ret = spi_map_msg(ctlr, ctlr->cur_msg);
1387         if (ret) {
1388                 ctlr->cur_msg->status = ret;
1389                 spi_finalize_current_message(ctlr);
1390                 goto out;
1391         }
1392
1393         ret = ctlr->transfer_one_message(ctlr, ctlr->cur_msg);
1394         if (ret) {
1395                 dev_err(&ctlr->dev,
1396                         "failed to transfer one message from queue\n");
1397                 goto out;
1398         }
1399
1400 out:
1401         mutex_unlock(&ctlr->io_mutex);
1402
1403         /* Prod the scheduler in case transfer_one() was busy waiting */
1404         if (!ret)
1405                 cond_resched();
1406 }
1407
1408 /**
1409  * spi_pump_messages - kthread work function which processes spi message queue
1410  * @work: pointer to kthread work struct contained in the controller struct
1411  */
1412 static void spi_pump_messages(struct kthread_work *work)
1413 {
1414         struct spi_controller *ctlr =
1415                 container_of(work, struct spi_controller, pump_messages);
1416
1417         __spi_pump_messages(ctlr, true);
1418 }
1419
1420 static int spi_init_queue(struct spi_controller *ctlr)
1421 {
1422         struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 };
1423
1424         ctlr->running = false;
1425         ctlr->busy = false;
1426
1427         kthread_init_worker(&ctlr->kworker);
1428         ctlr->kworker_task = kthread_run(kthread_worker_fn, &ctlr->kworker,
1429                                          "%s", dev_name(&ctlr->dev));
1430         if (IS_ERR(ctlr->kworker_task)) {
1431                 dev_err(&ctlr->dev, "failed to create message pump task\n");
1432                 return PTR_ERR(ctlr->kworker_task);
1433         }
1434         kthread_init_work(&ctlr->pump_messages, spi_pump_messages);
1435
1436         /*
1437          * Controller config will indicate if this controller should run the
1438          * message pump with high (realtime) priority to reduce the transfer
1439          * latency on the bus by minimising the delay between a transfer
1440          * request and the scheduling of the message pump thread. Without this
1441          * setting the message pump thread will remain at default priority.
1442          */
1443         if (ctlr->rt) {
1444                 dev_info(&ctlr->dev,
1445                         "will run message pump with realtime priority\n");
1446                 sched_setscheduler(ctlr->kworker_task, SCHED_FIFO, &param);
1447         }
1448
1449         return 0;
1450 }
1451
1452 /**
1453  * spi_get_next_queued_message() - called by driver to check for queued
1454  * messages
1455  * @ctlr: the controller to check for queued messages
1456  *
1457  * If there are more messages in the queue, the next message is returned from
1458  * this call.
1459  *
1460  * Return: the next message in the queue, else NULL if the queue is empty.
1461  */
1462 struct spi_message *spi_get_next_queued_message(struct spi_controller *ctlr)
1463 {
1464         struct spi_message *next;
1465         unsigned long flags;
1466
1467         /* get a pointer to the next message, if any */
1468         spin_lock_irqsave(&ctlr->queue_lock, flags);
1469         next = list_first_entry_or_null(&ctlr->queue, struct spi_message,
1470                                         queue);
1471         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1472
1473         return next;
1474 }
1475 EXPORT_SYMBOL_GPL(spi_get_next_queued_message);
1476
1477 /**
1478  * spi_finalize_current_message() - the current message is complete
1479  * @ctlr: the controller to return the message to
1480  *
1481  * Called by the driver to notify the core that the message in the front of the
1482  * queue is complete and can be removed from the queue.
1483  */
1484 void spi_finalize_current_message(struct spi_controller *ctlr)
1485 {
1486         struct spi_message *mesg;
1487         unsigned long flags;
1488         int ret;
1489
1490         spin_lock_irqsave(&ctlr->queue_lock, flags);
1491         mesg = ctlr->cur_msg;
1492         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1493
1494         spi_unmap_msg(ctlr, mesg);
1495
1496         if (ctlr->cur_msg_prepared && ctlr->unprepare_message) {
1497                 ret = ctlr->unprepare_message(ctlr, mesg);
1498                 if (ret) {
1499                         dev_err(&ctlr->dev, "failed to unprepare message: %d\n",
1500                                 ret);
1501                 }
1502         }
1503
1504         spin_lock_irqsave(&ctlr->queue_lock, flags);
1505         ctlr->cur_msg = NULL;
1506         ctlr->cur_msg_prepared = false;
1507         kthread_queue_work(&ctlr->kworker, &ctlr->pump_messages);
1508         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1509
1510         trace_spi_message_done(mesg);
1511
1512         mesg->state = NULL;
1513         if (mesg->complete)
1514                 mesg->complete(mesg->context);
1515 }
1516 EXPORT_SYMBOL_GPL(spi_finalize_current_message);
1517
1518 static int spi_start_queue(struct spi_controller *ctlr)
1519 {
1520         unsigned long flags;
1521
1522         spin_lock_irqsave(&ctlr->queue_lock, flags);
1523
1524         if (ctlr->running || ctlr->busy) {
1525                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1526                 return -EBUSY;
1527         }
1528
1529         ctlr->running = true;
1530         ctlr->cur_msg = NULL;
1531         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1532
1533         kthread_queue_work(&ctlr->kworker, &ctlr->pump_messages);
1534
1535         return 0;
1536 }
1537
1538 static int spi_stop_queue(struct spi_controller *ctlr)
1539 {
1540         unsigned long flags;
1541         unsigned limit = 500;
1542         int ret = 0;
1543
1544         spin_lock_irqsave(&ctlr->queue_lock, flags);
1545
1546         /*
1547          * This is a bit lame, but is optimized for the common execution path.
1548          * A wait_queue on the ctlr->busy could be used, but then the common
1549          * execution path (pump_messages) would be required to call wake_up or
1550          * friends on every SPI message. Do this instead.
1551          */
1552         while ((!list_empty(&ctlr->queue) || ctlr->busy) && limit--) {
1553                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1554                 usleep_range(10000, 11000);
1555                 spin_lock_irqsave(&ctlr->queue_lock, flags);
1556         }
1557
1558         if (!list_empty(&ctlr->queue) || ctlr->busy)
1559                 ret = -EBUSY;
1560         else
1561                 ctlr->running = false;
1562
1563         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1564
1565         if (ret) {
1566                 dev_warn(&ctlr->dev, "could not stop message queue\n");
1567                 return ret;
1568         }
1569         return ret;
1570 }
1571
1572 static int spi_destroy_queue(struct spi_controller *ctlr)
1573 {
1574         int ret;
1575
1576         ret = spi_stop_queue(ctlr);
1577
1578         /*
1579          * kthread_flush_worker will block until all work is done.
1580          * If the reason that stop_queue timed out is that the work will never
1581          * finish, then it does no good to call flush/stop thread, so
1582          * return anyway.
1583          */
1584         if (ret) {
1585                 dev_err(&ctlr->dev, "problem destroying queue\n");
1586                 return ret;
1587         }
1588
1589         kthread_flush_worker(&ctlr->kworker);
1590         kthread_stop(ctlr->kworker_task);
1591
1592         return 0;
1593 }
1594
1595 static int __spi_queued_transfer(struct spi_device *spi,
1596                                  struct spi_message *msg,
1597                                  bool need_pump)
1598 {
1599         struct spi_controller *ctlr = spi->controller;
1600         unsigned long flags;
1601
1602         spin_lock_irqsave(&ctlr->queue_lock, flags);
1603
1604         if (!ctlr->running) {
1605                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1606                 return -ESHUTDOWN;
1607         }
1608         msg->actual_length = 0;
1609         msg->status = -EINPROGRESS;
1610
1611         list_add_tail(&msg->queue, &ctlr->queue);
1612         if (!ctlr->busy && need_pump)
1613                 kthread_queue_work(&ctlr->kworker, &ctlr->pump_messages);
1614
1615         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1616         return 0;
1617 }
1618
1619 /**
1620  * spi_queued_transfer - transfer function for queued transfers
1621  * @spi: spi device which is requesting transfer
1622  * @msg: spi message which is to handled is queued to driver queue
1623  *
1624  * Return: zero on success, else a negative error code.
1625  */
1626 static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
1627 {
1628         return __spi_queued_transfer(spi, msg, true);
1629 }
1630
1631 static int spi_controller_initialize_queue(struct spi_controller *ctlr)
1632 {
1633         int ret;
1634
1635         ctlr->transfer = spi_queued_transfer;
1636         if (!ctlr->transfer_one_message)
1637                 ctlr->transfer_one_message = spi_transfer_one_message;
1638
1639         /* Initialize and start queue */
1640         ret = spi_init_queue(ctlr);
1641         if (ret) {
1642                 dev_err(&ctlr->dev, "problem initializing queue\n");
1643                 goto err_init_queue;
1644         }
1645         ctlr->queued = true;
1646         ret = spi_start_queue(ctlr);
1647         if (ret) {
1648                 dev_err(&ctlr->dev, "problem starting queue\n");
1649                 goto err_start_queue;
1650         }
1651
1652         return 0;
1653
1654 err_start_queue:
1655         spi_destroy_queue(ctlr);
1656 err_init_queue:
1657         return ret;
1658 }
1659
1660 /**
1661  * spi_flush_queue - Send all pending messages in the queue from the callers'
1662  *                   context
1663  * @ctlr: controller to process queue for
1664  *
1665  * This should be used when one wants to ensure all pending messages have been
1666  * sent before doing something. Is used by the spi-mem code to make sure SPI
1667  * memory operations do not preempt regular SPI transfers that have been queued
1668  * before the spi-mem operation.
1669  */
1670 void spi_flush_queue(struct spi_controller *ctlr)
1671 {
1672         if (ctlr->transfer == spi_queued_transfer)
1673                 __spi_pump_messages(ctlr, false);
1674 }
1675
1676 /*-------------------------------------------------------------------------*/
1677
1678 #if defined(CONFIG_OF)
1679 static int of_spi_parse_dt(struct spi_controller *ctlr, struct spi_device *spi,
1680                            struct device_node *nc)
1681 {
1682         u32 value;
1683         int rc;
1684
1685         /* Mode (clock phase/polarity/etc.) */
1686         if (of_property_read_bool(nc, "spi-cpha"))
1687                 spi->mode |= SPI_CPHA;
1688         if (of_property_read_bool(nc, "spi-cpol"))
1689                 spi->mode |= SPI_CPOL;
1690         if (of_property_read_bool(nc, "spi-3wire"))
1691                 spi->mode |= SPI_3WIRE;
1692         if (of_property_read_bool(nc, "spi-lsb-first"))
1693                 spi->mode |= SPI_LSB_FIRST;
1694
1695         /*
1696          * For descriptors associated with the device, polarity inversion is
1697          * handled in the gpiolib, so all chip selects are "active high" in
1698          * the logical sense, the gpiolib will invert the line if need be.
1699          */
1700         if (ctlr->use_gpio_descriptors)
1701                 spi->mode |= SPI_CS_HIGH;
1702         else if (of_property_read_bool(nc, "spi-cs-high"))
1703                 spi->mode |= SPI_CS_HIGH;
1704
1705         /* Device DUAL/QUAD mode */
1706         if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) {
1707                 switch (value) {
1708                 case 1:
1709                         break;
1710                 case 2:
1711                         spi->mode |= SPI_TX_DUAL;
1712                         break;
1713                 case 4:
1714                         spi->mode |= SPI_TX_QUAD;
1715                         break;
1716                 case 8:
1717                         spi->mode |= SPI_TX_OCTAL;
1718                         break;
1719                 default:
1720                         dev_warn(&ctlr->dev,
1721                                 "spi-tx-bus-width %d not supported\n",
1722                                 value);
1723                         break;
1724                 }
1725         }
1726
1727         if (!of_property_read_u32(nc, "spi-rx-bus-width", &value)) {
1728                 switch (value) {
1729                 case 1:
1730                         break;
1731                 case 2:
1732                         spi->mode |= SPI_RX_DUAL;
1733                         break;
1734                 case 4:
1735                         spi->mode |= SPI_RX_QUAD;
1736                         break;
1737                 case 8:
1738                         spi->mode |= SPI_RX_OCTAL;
1739                         break;
1740                 default:
1741                         dev_warn(&ctlr->dev,
1742                                 "spi-rx-bus-width %d not supported\n",
1743                                 value);
1744                         break;
1745                 }
1746         }
1747
1748         if (spi_controller_is_slave(ctlr)) {
1749                 if (!of_node_name_eq(nc, "slave")) {
1750                         dev_err(&ctlr->dev, "%pOF is not called 'slave'\n",
1751                                 nc);
1752                         return -EINVAL;
1753                 }
1754                 return 0;
1755         }
1756
1757         /* Device address */
1758         rc = of_property_read_u32(nc, "reg", &value);
1759         if (rc) {
1760                 dev_err(&ctlr->dev, "%pOF has no valid 'reg' property (%d)\n",
1761                         nc, rc);
1762                 return rc;
1763         }
1764         spi->chip_select = value;
1765
1766         /* Device speed */
1767         rc = of_property_read_u32(nc, "spi-max-frequency", &value);
1768         if (rc) {
1769                 dev_err(&ctlr->dev,
1770                         "%pOF has no valid 'spi-max-frequency' property (%d)\n", nc, rc);
1771                 return rc;
1772         }
1773         spi->max_speed_hz = value;
1774
1775         return 0;
1776 }
1777
1778 static struct spi_device *
1779 of_register_spi_device(struct spi_controller *ctlr, struct device_node *nc)
1780 {
1781         struct spi_device *spi;
1782         int rc;
1783
1784         /* Alloc an spi_device */
1785         spi = spi_alloc_device(ctlr);
1786         if (!spi) {
1787                 dev_err(&ctlr->dev, "spi_device alloc error for %pOF\n", nc);
1788                 rc = -ENOMEM;
1789                 goto err_out;
1790         }
1791
1792         /* Select device driver */
1793         rc = of_modalias_node(nc, spi->modalias,
1794                                 sizeof(spi->modalias));
1795         if (rc < 0) {
1796                 dev_err(&ctlr->dev, "cannot find modalias for %pOF\n", nc);
1797                 goto err_out;
1798         }
1799
1800         rc = of_spi_parse_dt(ctlr, spi, nc);
1801         if (rc)
1802                 goto err_out;
1803
1804         /* Store a pointer to the node in the device structure */
1805         of_node_get(nc);
1806         spi->dev.of_node = nc;
1807
1808         /* Register the new device */
1809         rc = spi_add_device(spi);
1810         if (rc) {
1811                 dev_err(&ctlr->dev, "spi_device register error %pOF\n", nc);
1812                 goto err_of_node_put;
1813         }
1814
1815         return spi;
1816
1817 err_of_node_put:
1818         of_node_put(nc);
1819 err_out:
1820         spi_dev_put(spi);
1821         return ERR_PTR(rc);
1822 }
1823
1824 /**
1825  * of_register_spi_devices() - Register child devices onto the SPI bus
1826  * @ctlr:       Pointer to spi_controller device
1827  *
1828  * Registers an spi_device for each child node of controller node which
1829  * represents a valid SPI slave.
1830  */
1831 static void of_register_spi_devices(struct spi_controller *ctlr)
1832 {
1833         struct spi_device *spi;
1834         struct device_node *nc;
1835
1836         if (!ctlr->dev.of_node)
1837                 return;
1838
1839         for_each_available_child_of_node(ctlr->dev.of_node, nc) {
1840                 if (of_node_test_and_set_flag(nc, OF_POPULATED))
1841                         continue;
1842                 spi = of_register_spi_device(ctlr, nc);
1843                 if (IS_ERR(spi)) {
1844                         dev_warn(&ctlr->dev,
1845                                  "Failed to create SPI device for %pOF\n", nc);
1846                         of_node_clear_flag(nc, OF_POPULATED);
1847                 }
1848         }
1849 }
1850 #else
1851 static void of_register_spi_devices(struct spi_controller *ctlr) { }
1852 #endif
1853
1854 #ifdef CONFIG_ACPI
1855 static void acpi_spi_parse_apple_properties(struct spi_device *spi)
1856 {
1857         struct acpi_device *dev = ACPI_COMPANION(&spi->dev);
1858         const union acpi_object *obj;
1859
1860         if (!x86_apple_machine)
1861                 return;
1862
1863         if (!acpi_dev_get_property(dev, "spiSclkPeriod", ACPI_TYPE_BUFFER, &obj)
1864             && obj->buffer.length >= 4)
1865                 spi->max_speed_hz  = NSEC_PER_SEC / *(u32 *)obj->buffer.pointer;
1866
1867         if (!acpi_dev_get_property(dev, "spiWordSize", ACPI_TYPE_BUFFER, &obj)
1868             && obj->buffer.length == 8)
1869                 spi->bits_per_word = *(u64 *)obj->buffer.pointer;
1870
1871         if (!acpi_dev_get_property(dev, "spiBitOrder", ACPI_TYPE_BUFFER, &obj)
1872             && obj->buffer.length == 8 && !*(u64 *)obj->buffer.pointer)
1873                 spi->mode |= SPI_LSB_FIRST;
1874
1875         if (!acpi_dev_get_property(dev, "spiSPO", ACPI_TYPE_BUFFER, &obj)
1876             && obj->buffer.length == 8 &&  *(u64 *)obj->buffer.pointer)
1877                 spi->mode |= SPI_CPOL;
1878
1879         if (!acpi_dev_get_property(dev, "spiSPH", ACPI_TYPE_BUFFER, &obj)
1880             && obj->buffer.length == 8 &&  *(u64 *)obj->buffer.pointer)
1881                 spi->mode |= SPI_CPHA;
1882 }
1883
1884 static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
1885 {
1886         struct spi_device *spi = data;
1887         struct spi_controller *ctlr = spi->controller;
1888
1889         if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
1890                 struct acpi_resource_spi_serialbus *sb;
1891
1892                 sb = &ares->data.spi_serial_bus;
1893                 if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) {
1894                         /*
1895                          * ACPI DeviceSelection numbering is handled by the
1896                          * host controller driver in Windows and can vary
1897                          * from driver to driver. In Linux we always expect
1898                          * 0 .. max - 1 so we need to ask the driver to
1899                          * translate between the two schemes.
1900                          */
1901                         if (ctlr->fw_translate_cs) {
1902                                 int cs = ctlr->fw_translate_cs(ctlr,
1903                                                 sb->device_selection);
1904                                 if (cs < 0)
1905                                         return cs;
1906                                 spi->chip_select = cs;
1907                         } else {
1908                                 spi->chip_select = sb->device_selection;
1909                         }
1910
1911                         spi->max_speed_hz = sb->connection_speed;
1912
1913                         if (sb->clock_phase == ACPI_SPI_SECOND_PHASE)
1914                                 spi->mode |= SPI_CPHA;
1915                         if (sb->clock_polarity == ACPI_SPI_START_HIGH)
1916                                 spi->mode |= SPI_CPOL;
1917                         if (sb->device_polarity == ACPI_SPI_ACTIVE_HIGH)
1918                                 spi->mode |= SPI_CS_HIGH;
1919                 }
1920         } else if (spi->irq < 0) {
1921                 struct resource r;
1922
1923                 if (acpi_dev_resource_interrupt(ares, 0, &r))
1924                         spi->irq = r.start;
1925         }
1926
1927         /* Always tell the ACPI core to skip this resource */
1928         return 1;
1929 }
1930
1931 static acpi_status acpi_register_spi_device(struct spi_controller *ctlr,
1932                                             struct acpi_device *adev)
1933 {
1934         struct list_head resource_list;
1935         struct spi_device *spi;
1936         int ret;
1937
1938         if (acpi_bus_get_status(adev) || !adev->status.present ||
1939             acpi_device_enumerated(adev))
1940                 return AE_OK;
1941
1942         spi = spi_alloc_device(ctlr);
1943         if (!spi) {
1944                 dev_err(&ctlr->dev, "failed to allocate SPI device for %s\n",
1945                         dev_name(&adev->dev));
1946                 return AE_NO_MEMORY;
1947         }
1948
1949         ACPI_COMPANION_SET(&spi->dev, adev);
1950         spi->irq = -1;
1951
1952         INIT_LIST_HEAD(&resource_list);
1953         ret = acpi_dev_get_resources(adev, &resource_list,
1954                                      acpi_spi_add_resource, spi);
1955         acpi_dev_free_resource_list(&resource_list);
1956
1957         acpi_spi_parse_apple_properties(spi);
1958
1959         if (ret < 0 || !spi->max_speed_hz) {
1960                 spi_dev_put(spi);
1961                 return AE_OK;
1962         }
1963
1964         acpi_set_modalias(adev, acpi_device_hid(adev), spi->modalias,
1965                           sizeof(spi->modalias));
1966
1967         if (spi->irq < 0)
1968                 spi->irq = acpi_dev_gpio_irq_get(adev, 0);
1969
1970         acpi_device_set_enumerated(adev);
1971
1972         adev->power.flags.ignore_parent = true;
1973         if (spi_add_device(spi)) {
1974                 adev->power.flags.ignore_parent = false;
1975                 dev_err(&ctlr->dev, "failed to add SPI device %s from ACPI\n",
1976                         dev_name(&adev->dev));
1977                 spi_dev_put(spi);
1978         }
1979
1980         return AE_OK;
1981 }
1982
1983 static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level,
1984                                        void *data, void **return_value)
1985 {
1986         struct spi_controller *ctlr = data;
1987         struct acpi_device *adev;
1988
1989         if (acpi_bus_get_device(handle, &adev))
1990                 return AE_OK;
1991
1992         return acpi_register_spi_device(ctlr, adev);
1993 }
1994
1995 static void acpi_register_spi_devices(struct spi_controller *ctlr)
1996 {
1997         acpi_status status;
1998         acpi_handle handle;
1999
2000         handle = ACPI_HANDLE(ctlr->dev.parent);
2001         if (!handle)
2002                 return;
2003
2004         status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
2005                                      acpi_spi_add_device, NULL, ctlr, NULL);
2006         if (ACPI_FAILURE(status))
2007                 dev_warn(&ctlr->dev, "failed to enumerate SPI slaves\n");
2008 }
2009 #else
2010 static inline void acpi_register_spi_devices(struct spi_controller *ctlr) {}
2011 #endif /* CONFIG_ACPI */
2012
2013 static void spi_controller_release(struct device *dev)
2014 {
2015         struct spi_controller *ctlr;
2016
2017         ctlr = container_of(dev, struct spi_controller, dev);
2018         kfree(ctlr);
2019 }
2020
2021 static struct class spi_master_class = {
2022         .name           = "spi_master",
2023         .owner          = THIS_MODULE,
2024         .dev_release    = spi_controller_release,
2025         .dev_groups     = spi_master_groups,
2026 };
2027
2028 #ifdef CONFIG_SPI_SLAVE
2029 /**
2030  * spi_slave_abort - abort the ongoing transfer request on an SPI slave
2031  *                   controller
2032  * @spi: device used for the current transfer
2033  */
2034 int spi_slave_abort(struct spi_device *spi)
2035 {
2036         struct spi_controller *ctlr = spi->controller;
2037
2038         if (spi_controller_is_slave(ctlr) && ctlr->slave_abort)
2039                 return ctlr->slave_abort(ctlr);
2040
2041         return -ENOTSUPP;
2042 }
2043 EXPORT_SYMBOL_GPL(spi_slave_abort);
2044
2045 static int match_true(struct device *dev, void *data)
2046 {
2047         return 1;
2048 }
2049
2050 static ssize_t spi_slave_show(struct device *dev,
2051                               struct device_attribute *attr, char *buf)
2052 {
2053         struct spi_controller *ctlr = container_of(dev, struct spi_controller,
2054                                                    dev);
2055         struct device *child;
2056
2057         child = device_find_child(&ctlr->dev, NULL, match_true);
2058         return sprintf(buf, "%s\n",
2059                        child ? to_spi_device(child)->modalias : NULL);
2060 }
2061
2062 static ssize_t spi_slave_store(struct device *dev,
2063                                struct device_attribute *attr, const char *buf,
2064                                size_t count)
2065 {
2066         struct spi_controller *ctlr = container_of(dev, struct spi_controller,
2067                                                    dev);
2068         struct spi_device *spi;
2069         struct device *child;
2070         char name[32];
2071         int rc;
2072
2073         rc = sscanf(buf, "%31s", name);
2074         if (rc != 1 || !name[0])
2075                 return -EINVAL;
2076
2077         child = device_find_child(&ctlr->dev, NULL, match_true);
2078         if (child) {
2079                 /* Remove registered slave */
2080                 device_unregister(child);
2081                 put_device(child);
2082         }
2083
2084         if (strcmp(name, "(null)")) {
2085                 /* Register new slave */
2086                 spi = spi_alloc_device(ctlr);
2087                 if (!spi)
2088                         return -ENOMEM;
2089
2090                 strlcpy(spi->modalias, name, sizeof(spi->modalias));
2091
2092                 rc = spi_add_device(spi);
2093                 if (rc) {
2094                         spi_dev_put(spi);
2095                         return rc;
2096                 }
2097         }
2098
2099         return count;
2100 }
2101
2102 static DEVICE_ATTR(slave, 0644, spi_slave_show, spi_slave_store);
2103
2104 static struct attribute *spi_slave_attrs[] = {
2105         &dev_attr_slave.attr,
2106         NULL,
2107 };
2108
2109 static const struct attribute_group spi_slave_group = {
2110         .attrs = spi_slave_attrs,
2111 };
2112
2113 static const struct attribute_group *spi_slave_groups[] = {
2114         &spi_controller_statistics_group,
2115         &spi_slave_group,
2116         NULL,
2117 };
2118
2119 static struct class spi_slave_class = {
2120         .name           = "spi_slave",
2121         .owner          = THIS_MODULE,
2122         .dev_release    = spi_controller_release,
2123         .dev_groups     = spi_slave_groups,
2124 };
2125 #else
2126 extern struct class spi_slave_class;    /* dummy */
2127 #endif
2128
2129 /**
2130  * __spi_alloc_controller - allocate an SPI master or slave controller
2131  * @dev: the controller, possibly using the platform_bus
2132  * @size: how much zeroed driver-private data to allocate; the pointer to this
2133  *      memory is in the driver_data field of the returned device,
2134  *      accessible with spi_controller_get_devdata().
2135  * @slave: flag indicating whether to allocate an SPI master (false) or SPI
2136  *      slave (true) controller
2137  * Context: can sleep
2138  *
2139  * This call is used only by SPI controller drivers, which are the
2140  * only ones directly touching chip registers.  It's how they allocate
2141  * an spi_controller structure, prior to calling spi_register_controller().
2142  *
2143  * This must be called from context that can sleep.
2144  *
2145  * The caller is responsible for assigning the bus number and initializing the
2146  * controller's methods before calling spi_register_controller(); and (after
2147  * errors adding the device) calling spi_controller_put() to prevent a memory
2148  * leak.
2149  *
2150  * Return: the SPI controller structure on success, else NULL.
2151  */
2152 struct spi_controller *__spi_alloc_controller(struct device *dev,
2153                                               unsigned int size, bool slave)
2154 {
2155         struct spi_controller   *ctlr;
2156
2157         if (!dev)
2158                 return NULL;
2159
2160         ctlr = kzalloc(size + sizeof(*ctlr), GFP_KERNEL);
2161         if (!ctlr)
2162                 return NULL;
2163
2164         device_initialize(&ctlr->dev);
2165         ctlr->bus_num = -1;
2166         ctlr->num_chipselect = 1;
2167         ctlr->slave = slave;
2168         if (IS_ENABLED(CONFIG_SPI_SLAVE) && slave)
2169                 ctlr->dev.class = &spi_slave_class;
2170         else
2171                 ctlr->dev.class = &spi_master_class;
2172         ctlr->dev.parent = dev;
2173         pm_suspend_ignore_children(&ctlr->dev, true);
2174         spi_controller_set_devdata(ctlr, &ctlr[1]);
2175
2176         return ctlr;
2177 }
2178 EXPORT_SYMBOL_GPL(__spi_alloc_controller);
2179
2180 #ifdef CONFIG_OF
2181 static int of_spi_register_master(struct spi_controller *ctlr)
2182 {
2183         int nb, i, *cs;
2184         struct device_node *np = ctlr->dev.of_node;
2185
2186         if (!np)
2187                 return 0;
2188
2189         nb = of_gpio_named_count(np, "cs-gpios");
2190         ctlr->num_chipselect = max_t(int, nb, ctlr->num_chipselect);
2191
2192         /* Return error only for an incorrectly formed cs-gpios property */
2193         if (nb == 0 || nb == -ENOENT)
2194                 return 0;
2195         else if (nb < 0)
2196                 return nb;
2197
2198         cs = devm_kcalloc(&ctlr->dev, ctlr->num_chipselect, sizeof(int),
2199                           GFP_KERNEL);
2200         ctlr->cs_gpios = cs;
2201
2202         if (!ctlr->cs_gpios)
2203                 return -ENOMEM;
2204
2205         for (i = 0; i < ctlr->num_chipselect; i++)
2206                 cs[i] = -ENOENT;
2207
2208         for (i = 0; i < nb; i++)
2209                 cs[i] = of_get_named_gpio(np, "cs-gpios", i);
2210
2211         return 0;
2212 }
2213 #else
2214 static int of_spi_register_master(struct spi_controller *ctlr)
2215 {
2216         return 0;
2217 }
2218 #endif
2219
2220 /**
2221  * spi_get_gpio_descs() - grab chip select GPIOs for the master
2222  * @ctlr: The SPI master to grab GPIO descriptors for
2223  */
2224 static int spi_get_gpio_descs(struct spi_controller *ctlr)
2225 {
2226         int nb, i;
2227         struct gpio_desc **cs;
2228         struct device *dev = &ctlr->dev;
2229
2230         nb = gpiod_count(dev, "cs");
2231         ctlr->num_chipselect = max_t(int, nb, ctlr->num_chipselect);
2232
2233         /* No GPIOs at all is fine, else return the error */
2234         if (nb == 0 || nb == -ENOENT)
2235                 return 0;
2236         else if (nb < 0)
2237                 return nb;
2238
2239         cs = devm_kcalloc(dev, ctlr->num_chipselect, sizeof(*cs),
2240                           GFP_KERNEL);
2241         if (!cs)
2242                 return -ENOMEM;
2243         ctlr->cs_gpiods = cs;
2244
2245         for (i = 0; i < nb; i++) {
2246                 /*
2247                  * Most chipselects are active low, the inverted
2248                  * semantics are handled by special quirks in gpiolib,
2249                  * so initializing them GPIOD_OUT_LOW here means
2250                  * "unasserted", in most cases this will drive the physical
2251                  * line high.
2252                  */
2253                 cs[i] = devm_gpiod_get_index_optional(dev, "cs", i,
2254                                                       GPIOD_OUT_LOW);
2255                 if (IS_ERR(cs[i]))
2256                         return PTR_ERR(cs[i]);
2257
2258                 if (cs[i]) {
2259                         /*
2260                          * If we find a CS GPIO, name it after the device and
2261                          * chip select line.
2262                          */
2263                         char *gpioname;
2264
2265                         gpioname = devm_kasprintf(dev, GFP_KERNEL, "%s CS%d",
2266                                                   dev_name(dev), i);
2267                         if (!gpioname)
2268                                 return -ENOMEM;
2269                         gpiod_set_consumer_name(cs[i], gpioname);
2270                 }
2271         }
2272
2273         return 0;
2274 }
2275
2276 static int spi_controller_check_ops(struct spi_controller *ctlr)
2277 {
2278         /*
2279          * The controller may implement only the high-level SPI-memory like
2280          * operations if it does not support regular SPI transfers, and this is
2281          * valid use case.
2282          * If ->mem_ops is NULL, we request that at least one of the
2283          * ->transfer_xxx() method be implemented.
2284          */
2285         if (ctlr->mem_ops) {
2286                 if (!ctlr->mem_ops->exec_op)
2287                         return -EINVAL;
2288         } else if (!ctlr->transfer && !ctlr->transfer_one &&
2289                    !ctlr->transfer_one_message) {
2290                 return -EINVAL;
2291         }
2292
2293         return 0;
2294 }
2295
2296 /**
2297  * spi_register_controller - register SPI master or slave controller
2298  * @ctlr: initialized master, originally from spi_alloc_master() or
2299  *      spi_alloc_slave()
2300  * Context: can sleep
2301  *
2302  * SPI controllers connect to their drivers using some non-SPI bus,
2303  * such as the platform bus.  The final stage of probe() in that code
2304  * includes calling spi_register_controller() to hook up to this SPI bus glue.
2305  *
2306  * SPI controllers use board specific (often SOC specific) bus numbers,
2307  * and board-specific addressing for SPI devices combines those numbers
2308  * with chip select numbers.  Since SPI does not directly support dynamic
2309  * device identification, boards need configuration tables telling which
2310  * chip is at which address.
2311  *
2312  * This must be called from context that can sleep.  It returns zero on
2313  * success, else a negative error code (dropping the controller's refcount).
2314  * After a successful return, the caller is responsible for calling
2315  * spi_unregister_controller().
2316  *
2317  * Return: zero on success, else a negative error code.
2318  */
2319 int spi_register_controller(struct spi_controller *ctlr)
2320 {
2321         struct device           *dev = ctlr->dev.parent;
2322         struct boardinfo        *bi;
2323         int                     status;
2324         int                     id, first_dynamic;
2325
2326         if (!dev)
2327                 return -ENODEV;
2328
2329         /*
2330          * Make sure all necessary hooks are implemented before registering
2331          * the SPI controller.
2332          */
2333         status = spi_controller_check_ops(ctlr);
2334         if (status)
2335                 return status;
2336
2337         /* even if it's just one always-selected device, there must
2338          * be at least one chipselect
2339          */
2340         if (ctlr->num_chipselect == 0)
2341                 return -EINVAL;
2342         if (ctlr->bus_num >= 0) {
2343                 /* devices with a fixed bus num must check-in with the num */
2344                 mutex_lock(&board_lock);
2345                 id = idr_alloc(&spi_master_idr, ctlr, ctlr->bus_num,
2346                         ctlr->bus_num + 1, GFP_KERNEL);
2347                 mutex_unlock(&board_lock);
2348                 if (WARN(id < 0, "couldn't get idr"))
2349                         return id == -ENOSPC ? -EBUSY : id;
2350                 ctlr->bus_num = id;
2351         } else if (ctlr->dev.of_node) {
2352                 /* allocate dynamic bus number using Linux idr */
2353                 id = of_alias_get_id(ctlr->dev.of_node, "spi");
2354                 if (id >= 0) {
2355                         ctlr->bus_num = id;
2356                         mutex_lock(&board_lock);
2357                         id = idr_alloc(&spi_master_idr, ctlr, ctlr->bus_num,
2358                                        ctlr->bus_num + 1, GFP_KERNEL);
2359                         mutex_unlock(&board_lock);
2360                         if (WARN(id < 0, "couldn't get idr"))
2361                                 return id == -ENOSPC ? -EBUSY : id;
2362                 }
2363         }
2364         if (ctlr->bus_num < 0) {
2365                 first_dynamic = of_alias_get_highest_id("spi");
2366                 if (first_dynamic < 0)
2367                         first_dynamic = 0;
2368                 else
2369                         first_dynamic++;
2370
2371                 mutex_lock(&board_lock);
2372                 id = idr_alloc(&spi_master_idr, ctlr, first_dynamic,
2373                                0, GFP_KERNEL);
2374                 mutex_unlock(&board_lock);
2375                 if (WARN(id < 0, "couldn't get idr"))
2376                         return id;
2377                 ctlr->bus_num = id;
2378         }
2379         INIT_LIST_HEAD(&ctlr->queue);
2380         spin_lock_init(&ctlr->queue_lock);
2381         spin_lock_init(&ctlr->bus_lock_spinlock);
2382         mutex_init(&ctlr->bus_lock_mutex);
2383         mutex_init(&ctlr->io_mutex);
2384         ctlr->bus_lock_flag = 0;
2385         init_completion(&ctlr->xfer_completion);
2386         if (!ctlr->max_dma_len)
2387                 ctlr->max_dma_len = INT_MAX;
2388
2389         /* register the device, then userspace will see it.
2390          * registration fails if the bus ID is in use.
2391          */
2392         dev_set_name(&ctlr->dev, "spi%u", ctlr->bus_num);
2393
2394         if (!spi_controller_is_slave(ctlr)) {
2395                 if (ctlr->use_gpio_descriptors) {
2396                         status = spi_get_gpio_descs(ctlr);
2397                         if (status)
2398                                 return status;
2399                         /*
2400                          * A controller using GPIO descriptors always
2401                          * supports SPI_CS_HIGH if need be.
2402                          */
2403                         ctlr->mode_bits |= SPI_CS_HIGH;
2404                 } else {
2405                         /* Legacy code path for GPIOs from DT */
2406                         status = of_spi_register_master(ctlr);
2407                         if (status)
2408                                 return status;
2409                 }
2410         }
2411
2412         status = device_add(&ctlr->dev);
2413         if (status < 0) {
2414                 /* free bus id */
2415                 mutex_lock(&board_lock);
2416                 idr_remove(&spi_master_idr, ctlr->bus_num);
2417                 mutex_unlock(&board_lock);
2418                 goto done;
2419         }
2420         dev_dbg(dev, "registered %s %s\n",
2421                         spi_controller_is_slave(ctlr) ? "slave" : "master",
2422                         dev_name(&ctlr->dev));
2423
2424         /*
2425          * If we're using a queued driver, start the queue. Note that we don't
2426          * need the queueing logic if the driver is only supporting high-level
2427          * memory operations.
2428          */
2429         if (ctlr->transfer) {
2430                 dev_info(dev, "controller is unqueued, this is deprecated\n");
2431         } else if (ctlr->transfer_one || ctlr->transfer_one_message) {
2432                 status = spi_controller_initialize_queue(ctlr);
2433                 if (status) {
2434                         device_del(&ctlr->dev);
2435                         /* free bus id */
2436                         mutex_lock(&board_lock);
2437                         idr_remove(&spi_master_idr, ctlr->bus_num);
2438                         mutex_unlock(&board_lock);
2439                         goto done;
2440                 }
2441         }
2442         /* add statistics */
2443         spin_lock_init(&ctlr->statistics.lock);
2444
2445         mutex_lock(&board_lock);
2446         list_add_tail(&ctlr->list, &spi_controller_list);
2447         list_for_each_entry(bi, &board_list, list)
2448                 spi_match_controller_to_boardinfo(ctlr, &bi->board_info);
2449         mutex_unlock(&board_lock);
2450
2451         /* Register devices from the device tree and ACPI */
2452         of_register_spi_devices(ctlr);
2453         acpi_register_spi_devices(ctlr);
2454 done:
2455         return status;
2456 }
2457 EXPORT_SYMBOL_GPL(spi_register_controller);
2458
2459 static void devm_spi_unregister(struct device *dev, void *res)
2460 {
2461         spi_unregister_controller(*(struct spi_controller **)res);
2462 }
2463
2464 /**
2465  * devm_spi_register_controller - register managed SPI master or slave
2466  *      controller
2467  * @dev:    device managing SPI controller
2468  * @ctlr: initialized controller, originally from spi_alloc_master() or
2469  *      spi_alloc_slave()
2470  * Context: can sleep
2471  *
2472  * Register a SPI device as with spi_register_controller() which will
2473  * automatically be unregistered and freed.
2474  *
2475  * Return: zero on success, else a negative error code.
2476  */
2477 int devm_spi_register_controller(struct device *dev,
2478                                  struct spi_controller *ctlr)
2479 {
2480         struct spi_controller **ptr;
2481         int ret;
2482
2483         ptr = devres_alloc(devm_spi_unregister, sizeof(*ptr), GFP_KERNEL);
2484         if (!ptr)
2485                 return -ENOMEM;
2486
2487         ret = spi_register_controller(ctlr);
2488         if (!ret) {
2489                 *ptr = ctlr;
2490                 devres_add(dev, ptr);
2491         } else {
2492                 devres_free(ptr);
2493         }
2494
2495         return ret;
2496 }
2497 EXPORT_SYMBOL_GPL(devm_spi_register_controller);
2498
2499 static int __unregister(struct device *dev, void *null)
2500 {
2501         spi_unregister_device(to_spi_device(dev));
2502         return 0;
2503 }
2504
2505 /**
2506  * spi_unregister_controller - unregister SPI master or slave controller
2507  * @ctlr: the controller being unregistered
2508  * Context: can sleep
2509  *
2510  * This call is used only by SPI controller drivers, which are the
2511  * only ones directly touching chip registers.
2512  *
2513  * This must be called from context that can sleep.
2514  *
2515  * Note that this function also drops a reference to the controller.
2516  */
2517 void spi_unregister_controller(struct spi_controller *ctlr)
2518 {
2519         struct spi_controller *found;
2520         int id = ctlr->bus_num;
2521         int dummy;
2522
2523         /* First make sure that this controller was ever added */
2524         mutex_lock(&board_lock);
2525         found = idr_find(&spi_master_idr, id);
2526         mutex_unlock(&board_lock);
2527         if (ctlr->queued) {
2528                 if (spi_destroy_queue(ctlr))
2529                         dev_err(&ctlr->dev, "queue remove failed\n");
2530         }
2531         mutex_lock(&board_lock);
2532         list_del(&ctlr->list);
2533         mutex_unlock(&board_lock);
2534
2535         dummy = device_for_each_child(&ctlr->dev, NULL, __unregister);
2536         device_unregister(&ctlr->dev);
2537         /* free bus id */
2538         mutex_lock(&board_lock);
2539         if (found == ctlr)
2540                 idr_remove(&spi_master_idr, id);
2541         mutex_unlock(&board_lock);
2542 }
2543 EXPORT_SYMBOL_GPL(spi_unregister_controller);
2544
2545 int spi_controller_suspend(struct spi_controller *ctlr)
2546 {
2547         int ret;
2548
2549         /* Basically no-ops for non-queued controllers */
2550         if (!ctlr->queued)
2551                 return 0;
2552
2553         ret = spi_stop_queue(ctlr);
2554         if (ret)
2555                 dev_err(&ctlr->dev, "queue stop failed\n");
2556
2557         return ret;
2558 }
2559 EXPORT_SYMBOL_GPL(spi_controller_suspend);
2560
2561 int spi_controller_resume(struct spi_controller *ctlr)
2562 {
2563         int ret;
2564
2565         if (!ctlr->queued)
2566                 return 0;
2567
2568         ret = spi_start_queue(ctlr);
2569         if (ret)
2570                 dev_err(&ctlr->dev, "queue restart failed\n");
2571
2572         return ret;
2573 }
2574 EXPORT_SYMBOL_GPL(spi_controller_resume);
2575
2576 static int __spi_controller_match(struct device *dev, const void *data)
2577 {
2578         struct spi_controller *ctlr;
2579         const u16 *bus_num = data;
2580
2581         ctlr = container_of(dev, struct spi_controller, dev);
2582         return ctlr->bus_num == *bus_num;
2583 }
2584
2585 /**
2586  * spi_busnum_to_master - look up master associated with bus_num
2587  * @bus_num: the master's bus number
2588  * Context: can sleep
2589  *
2590  * This call may be used with devices that are registered after
2591  * arch init time.  It returns a refcounted pointer to the relevant
2592  * spi_controller (which the caller must release), or NULL if there is
2593  * no such master registered.
2594  *
2595  * Return: the SPI master structure on success, else NULL.
2596  */
2597 struct spi_controller *spi_busnum_to_master(u16 bus_num)
2598 {
2599         struct device           *dev;
2600         struct spi_controller   *ctlr = NULL;
2601
2602         dev = class_find_device(&spi_master_class, NULL, &bus_num,
2603                                 __spi_controller_match);
2604         if (dev)
2605                 ctlr = container_of(dev, struct spi_controller, dev);
2606         /* reference got in class_find_device */
2607         return ctlr;
2608 }
2609 EXPORT_SYMBOL_GPL(spi_busnum_to_master);
2610
2611 /*-------------------------------------------------------------------------*/
2612
2613 /* Core methods for SPI resource management */
2614
2615 /**
2616  * spi_res_alloc - allocate a spi resource that is life-cycle managed
2617  *                 during the processing of a spi_message while using
2618  *                 spi_transfer_one
2619  * @spi:     the spi device for which we allocate memory
2620  * @release: the release code to execute for this resource
2621  * @size:    size to alloc and return
2622  * @gfp:     GFP allocation flags
2623  *
2624  * Return: the pointer to the allocated data
2625  *
2626  * This may get enhanced in the future to allocate from a memory pool
2627  * of the @spi_device or @spi_controller to avoid repeated allocations.
2628  */
2629 void *spi_res_alloc(struct spi_device *spi,
2630                     spi_res_release_t release,
2631                     size_t size, gfp_t gfp)
2632 {
2633         struct spi_res *sres;
2634
2635         sres = kzalloc(sizeof(*sres) + size, gfp);
2636         if (!sres)
2637                 return NULL;
2638
2639         INIT_LIST_HEAD(&sres->entry);
2640         sres->release = release;
2641
2642         return sres->data;
2643 }
2644 EXPORT_SYMBOL_GPL(spi_res_alloc);
2645
2646 /**
2647  * spi_res_free - free an spi resource
2648  * @res: pointer to the custom data of a resource
2649  *
2650  */
2651 void spi_res_free(void *res)
2652 {
2653         struct spi_res *sres = container_of(res, struct spi_res, data);
2654
2655         if (!res)
2656                 return;
2657
2658         WARN_ON(!list_empty(&sres->entry));
2659         kfree(sres);
2660 }
2661 EXPORT_SYMBOL_GPL(spi_res_free);
2662
2663 /**
2664  * spi_res_add - add a spi_res to the spi_message
2665  * @message: the spi message
2666  * @res:     the spi_resource
2667  */
2668 void spi_res_add(struct spi_message *message, void *res)
2669 {
2670         struct spi_res *sres = container_of(res, struct spi_res, data);
2671
2672         WARN_ON(!list_empty(&sres->entry));
2673         list_add_tail(&sres->entry, &message->resources);
2674 }
2675 EXPORT_SYMBOL_GPL(spi_res_add);
2676
2677 /**
2678  * spi_res_release - release all spi resources for this message
2679  * @ctlr:  the @spi_controller
2680  * @message: the @spi_message
2681  */
2682 void spi_res_release(struct spi_controller *ctlr, struct spi_message *message)
2683 {
2684         struct spi_res *res;
2685
2686         while (!list_empty(&message->resources)) {
2687                 res = list_last_entry(&message->resources,
2688                                       struct spi_res, entry);
2689
2690                 if (res->release)
2691                         res->release(ctlr, message, res->data);
2692
2693                 list_del(&res->entry);
2694
2695                 kfree(res);
2696         }
2697 }
2698 EXPORT_SYMBOL_GPL(spi_res_release);
2699
2700 /*-------------------------------------------------------------------------*/
2701
2702 /* Core methods for spi_message alterations */
2703
2704 static void __spi_replace_transfers_release(struct spi_controller *ctlr,
2705                                             struct spi_message *msg,
2706                                             void *res)
2707 {
2708         struct spi_replaced_transfers *rxfer = res;
2709         size_t i;
2710
2711         /* call extra callback if requested */
2712         if (rxfer->release)
2713                 rxfer->release(ctlr, msg, res);
2714
2715         /* insert replaced transfers back into the message */
2716         list_splice(&rxfer->replaced_transfers, rxfer->replaced_after);
2717
2718         /* remove the formerly inserted entries */
2719         for (i = 0; i < rxfer->inserted; i++)
2720                 list_del(&rxfer->inserted_transfers[i].transfer_list);
2721 }
2722
2723 /**
2724  * spi_replace_transfers - replace transfers with several transfers
2725  *                         and register change with spi_message.resources
2726  * @msg:           the spi_message we work upon
2727  * @xfer_first:    the first spi_transfer we want to replace
2728  * @remove:        number of transfers to remove
2729  * @insert:        the number of transfers we want to insert instead
2730  * @release:       extra release code necessary in some circumstances
2731  * @extradatasize: extra data to allocate (with alignment guarantees
2732  *                 of struct @spi_transfer)
2733  * @gfp:           gfp flags
2734  *
2735  * Returns: pointer to @spi_replaced_transfers,
2736  *          PTR_ERR(...) in case of errors.
2737  */
2738 struct spi_replaced_transfers *spi_replace_transfers(
2739         struct spi_message *msg,
2740         struct spi_transfer *xfer_first,
2741         size_t remove,
2742         size_t insert,
2743         spi_replaced_release_t release,
2744         size_t extradatasize,
2745         gfp_t gfp)
2746 {
2747         struct spi_replaced_transfers *rxfer;
2748         struct spi_transfer *xfer;
2749         size_t i;
2750
2751         /* allocate the structure using spi_res */
2752         rxfer = spi_res_alloc(msg->spi, __spi_replace_transfers_release,
2753                               insert * sizeof(struct spi_transfer)
2754                               + sizeof(struct spi_replaced_transfers)
2755                               + extradatasize,
2756                               gfp);
2757         if (!rxfer)
2758                 return ERR_PTR(-ENOMEM);
2759
2760         /* the release code to invoke before running the generic release */
2761         rxfer->release = release;
2762
2763         /* assign extradata */
2764         if (extradatasize)
2765                 rxfer->extradata =
2766                         &rxfer->inserted_transfers[insert];
2767
2768         /* init the replaced_transfers list */
2769         INIT_LIST_HEAD(&rxfer->replaced_transfers);
2770
2771         /* assign the list_entry after which we should reinsert
2772          * the @replaced_transfers - it may be spi_message.messages!
2773          */
2774         rxfer->replaced_after = xfer_first->transfer_list.prev;
2775
2776         /* remove the requested number of transfers */
2777         for (i = 0; i < remove; i++) {
2778                 /* if the entry after replaced_after it is msg->transfers
2779                  * then we have been requested to remove more transfers
2780                  * than are in the list
2781                  */
2782                 if (rxfer->replaced_after->next == &msg->transfers) {
2783                         dev_err(&msg->spi->dev,
2784                                 "requested to remove more spi_transfers than are available\n");
2785                         /* insert replaced transfers back into the message */
2786                         list_splice(&rxfer->replaced_transfers,
2787                                     rxfer->replaced_after);
2788
2789                         /* free the spi_replace_transfer structure */
2790                         spi_res_free(rxfer);
2791
2792                         /* and return with an error */
2793                         return ERR_PTR(-EINVAL);
2794                 }
2795
2796                 /* remove the entry after replaced_after from list of
2797                  * transfers and add it to list of replaced_transfers
2798                  */
2799                 list_move_tail(rxfer->replaced_after->next,
2800                                &rxfer->replaced_transfers);
2801         }
2802
2803         /* create copy of the given xfer with identical settings
2804          * based on the first transfer to get removed
2805          */
2806         for (i = 0; i < insert; i++) {
2807                 /* we need to run in reverse order */
2808                 xfer = &rxfer->inserted_transfers[insert - 1 - i];
2809
2810                 /* copy all spi_transfer data */
2811                 memcpy(xfer, xfer_first, sizeof(*xfer));
2812
2813                 /* add to list */
2814                 list_add(&xfer->transfer_list, rxfer->replaced_after);
2815
2816                 /* clear cs_change and delay_usecs for all but the last */
2817                 if (i) {
2818                         xfer->cs_change = false;
2819                         xfer->delay_usecs = 0;
2820                 }
2821         }
2822
2823         /* set up inserted */
2824         rxfer->inserted = insert;
2825
2826         /* and register it with spi_res/spi_message */
2827         spi_res_add(msg, rxfer);
2828
2829         return rxfer;
2830 }
2831 EXPORT_SYMBOL_GPL(spi_replace_transfers);
2832
2833 static int __spi_split_transfer_maxsize(struct spi_controller *ctlr,
2834                                         struct spi_message *msg,
2835                                         struct spi_transfer **xferp,
2836                                         size_t maxsize,
2837                                         gfp_t gfp)
2838 {
2839         struct spi_transfer *xfer = *xferp, *xfers;
2840         struct spi_replaced_transfers *srt;
2841         size_t offset;
2842         size_t count, i;
2843
2844         /* calculate how many we have to replace */
2845         count = DIV_ROUND_UP(xfer->len, maxsize);
2846
2847         /* create replacement */
2848         srt = spi_replace_transfers(msg, xfer, 1, count, NULL, 0, gfp);
2849         if (IS_ERR(srt))
2850                 return PTR_ERR(srt);
2851         xfers = srt->inserted_transfers;
2852
2853         /* now handle each of those newly inserted spi_transfers
2854          * note that the replacements spi_transfers all are preset
2855          * to the same values as *xferp, so tx_buf, rx_buf and len
2856          * are all identical (as well as most others)
2857          * so we just have to fix up len and the pointers.
2858          *
2859          * this also includes support for the depreciated
2860          * spi_message.is_dma_mapped interface
2861          */
2862
2863         /* the first transfer just needs the length modified, so we
2864          * run it outside the loop
2865          */
2866         xfers[0].len = min_t(size_t, maxsize, xfer[0].len);
2867
2868         /* all the others need rx_buf/tx_buf also set */
2869         for (i = 1, offset = maxsize; i < count; offset += maxsize, i++) {
2870                 /* update rx_buf, tx_buf and dma */
2871                 if (xfers[i].rx_buf)
2872                         xfers[i].rx_buf += offset;
2873                 if (xfers[i].rx_dma)
2874                         xfers[i].rx_dma += offset;
2875                 if (xfers[i].tx_buf)
2876                         xfers[i].tx_buf += offset;
2877                 if (xfers[i].tx_dma)
2878                         xfers[i].tx_dma += offset;
2879
2880                 /* update length */
2881                 xfers[i].len = min(maxsize, xfers[i].len - offset);
2882         }
2883
2884         /* we set up xferp to the last entry we have inserted,
2885          * so that we skip those already split transfers
2886          */
2887         *xferp = &xfers[count - 1];
2888
2889         /* increment statistics counters */
2890         SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics,
2891                                        transfers_split_maxsize);
2892         SPI_STATISTICS_INCREMENT_FIELD(&msg->spi->statistics,
2893                                        transfers_split_maxsize);
2894
2895         return 0;
2896 }
2897
2898 /**
2899  * spi_split_tranfers_maxsize - split spi transfers into multiple transfers
2900  *                              when an individual transfer exceeds a
2901  *                              certain size
2902  * @ctlr:    the @spi_controller for this transfer
2903  * @msg:   the @spi_message to transform
2904  * @maxsize:  the maximum when to apply this
2905  * @gfp: GFP allocation flags
2906  *
2907  * Return: status of transformation
2908  */
2909 int spi_split_transfers_maxsize(struct spi_controller *ctlr,
2910                                 struct spi_message *msg,
2911                                 size_t maxsize,
2912                                 gfp_t gfp)
2913 {
2914         struct spi_transfer *xfer;
2915         int ret;
2916
2917         /* iterate over the transfer_list,
2918          * but note that xfer is advanced to the last transfer inserted
2919          * to avoid checking sizes again unnecessarily (also xfer does
2920          * potentiall belong to a different list by the time the
2921          * replacement has happened
2922          */
2923         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
2924                 if (xfer->len > maxsize) {
2925                         ret = __spi_split_transfer_maxsize(ctlr, msg, &xfer,
2926                                                            maxsize, gfp);
2927                         if (ret)
2928                                 return ret;
2929                 }
2930         }
2931
2932         return 0;
2933 }
2934 EXPORT_SYMBOL_GPL(spi_split_transfers_maxsize);
2935
2936 /*-------------------------------------------------------------------------*/
2937
2938 /* Core methods for SPI controller protocol drivers.  Some of the
2939  * other core methods are currently defined as inline functions.
2940  */
2941
2942 static int __spi_validate_bits_per_word(struct spi_controller *ctlr,
2943                                         u8 bits_per_word)
2944 {
2945         if (ctlr->bits_per_word_mask) {
2946                 /* Only 32 bits fit in the mask */
2947                 if (bits_per_word > 32)
2948                         return -EINVAL;
2949                 if (!(ctlr->bits_per_word_mask & SPI_BPW_MASK(bits_per_word)))
2950                         return -EINVAL;
2951         }
2952
2953         return 0;
2954 }
2955
2956 /**
2957  * spi_setup - setup SPI mode and clock rate
2958  * @spi: the device whose settings are being modified
2959  * Context: can sleep, and no requests are queued to the device
2960  *
2961  * SPI protocol drivers may need to update the transfer mode if the
2962  * device doesn't work with its default.  They may likewise need
2963  * to update clock rates or word sizes from initial values.  This function
2964  * changes those settings, and must be called from a context that can sleep.
2965  * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
2966  * effect the next time the device is selected and data is transferred to
2967  * or from it.  When this function returns, the spi device is deselected.
2968  *
2969  * Note that this call will fail if the protocol driver specifies an option
2970  * that the underlying controller or its driver does not support.  For
2971  * example, not all hardware supports wire transfers using nine bit words,
2972  * LSB-first wire encoding, or active-high chipselects.
2973  *
2974  * Return: zero on success, else a negative error code.
2975  */
2976 int spi_setup(struct spi_device *spi)
2977 {
2978         unsigned        bad_bits, ugly_bits;
2979         int             status;
2980
2981         /* check mode to prevent that DUAL and QUAD set at the same time
2982          */
2983         if (((spi->mode & SPI_TX_DUAL) && (spi->mode & SPI_TX_QUAD)) ||
2984                 ((spi->mode & SPI_RX_DUAL) && (spi->mode & SPI_RX_QUAD))) {
2985                 dev_err(&spi->dev,
2986                 "setup: can not select dual and quad at the same time\n");
2987                 return -EINVAL;
2988         }
2989         /* if it is SPI_3WIRE mode, DUAL and QUAD should be forbidden
2990          */
2991         if ((spi->mode & SPI_3WIRE) && (spi->mode &
2992                 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_TX_OCTAL |
2993                  SPI_RX_DUAL | SPI_RX_QUAD | SPI_RX_OCTAL)))
2994                 return -EINVAL;
2995         /* help drivers fail *cleanly* when they need options
2996          * that aren't supported with their current controller
2997          * SPI_CS_WORD has a fallback software implementation,
2998          * so it is ignored here.
2999          */
3000         bad_bits = spi->mode & ~(spi->controller->mode_bits | SPI_CS_WORD);
3001         /* nothing prevents from working with active-high CS in case if it
3002          * is driven by GPIO.
3003          */
3004         if (gpio_is_valid(spi->cs_gpio))
3005                 bad_bits &= ~SPI_CS_HIGH;
3006         ugly_bits = bad_bits &
3007                     (SPI_TX_DUAL | SPI_TX_QUAD | SPI_TX_OCTAL |
3008                      SPI_RX_DUAL | SPI_RX_QUAD | SPI_RX_OCTAL);
3009         if (ugly_bits) {
3010                 dev_warn(&spi->dev,
3011                          "setup: ignoring unsupported mode bits %x\n",
3012                          ugly_bits);
3013                 spi->mode &= ~ugly_bits;
3014                 bad_bits &= ~ugly_bits;
3015         }
3016         if (bad_bits) {
3017                 dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
3018                         bad_bits);
3019                 return -EINVAL;
3020         }
3021
3022         if (!spi->bits_per_word)
3023                 spi->bits_per_word = 8;
3024
3025         status = __spi_validate_bits_per_word(spi->controller,
3026                                               spi->bits_per_word);
3027         if (status)
3028                 return status;
3029
3030         if (!spi->max_speed_hz)
3031                 spi->max_speed_hz = spi->controller->max_speed_hz;
3032
3033         if (spi->controller->setup)
3034                 status = spi->controller->setup(spi);
3035
3036         spi_set_cs(spi, false);
3037
3038         dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
3039                         (int) (spi->mode & (SPI_CPOL | SPI_CPHA)),
3040                         (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
3041                         (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
3042                         (spi->mode & SPI_3WIRE) ? "3wire, " : "",
3043                         (spi->mode & SPI_LOOP) ? "loopback, " : "",
3044                         spi->bits_per_word, spi->max_speed_hz,
3045                         status);
3046
3047         return status;
3048 }
3049 EXPORT_SYMBOL_GPL(spi_setup);
3050
3051 /**
3052  * spi_set_cs_timing - configure CS setup, hold, and inactive delays
3053  * @spi: the device that requires specific CS timing configuration
3054  * @setup: CS setup time in terms of clock count
3055  * @hold: CS hold time in terms of clock count
3056  * @inactive_dly: CS inactive delay between transfers in terms of clock count
3057  */
3058 void spi_set_cs_timing(struct spi_device *spi, u8 setup, u8 hold,
3059                        u8 inactive_dly)
3060 {
3061         if (spi->controller->set_cs_timing)
3062                 spi->controller->set_cs_timing(spi, setup, hold, inactive_dly);
3063 }
3064 EXPORT_SYMBOL_GPL(spi_set_cs_timing);
3065
3066 static int __spi_validate(struct spi_device *spi, struct spi_message *message)
3067 {
3068         struct spi_controller *ctlr = spi->controller;
3069         struct spi_transfer *xfer;
3070         int w_size;
3071
3072         if (list_empty(&message->transfers))
3073                 return -EINVAL;
3074
3075         /* If an SPI controller does not support toggling the CS line on each
3076          * transfer (indicated by the SPI_CS_WORD flag) or we are using a GPIO
3077          * for the CS line, we can emulate the CS-per-word hardware function by
3078          * splitting transfers into one-word transfers and ensuring that
3079          * cs_change is set for each transfer.
3080          */
3081         if ((spi->mode & SPI_CS_WORD) && (!(ctlr->mode_bits & SPI_CS_WORD) ||
3082                                           spi->cs_gpiod ||
3083                                           gpio_is_valid(spi->cs_gpio))) {
3084                 size_t maxsize;
3085                 int ret;
3086
3087                 maxsize = (spi->bits_per_word + 7) / 8;
3088
3089                 /* spi_split_transfers_maxsize() requires message->spi */
3090                 message->spi = spi;
3091
3092                 ret = spi_split_transfers_maxsize(ctlr, message, maxsize,
3093                                                   GFP_KERNEL);
3094                 if (ret)
3095                         return ret;
3096
3097                 list_for_each_entry(xfer, &message->transfers, transfer_list) {
3098                         /* don't change cs_change on the last entry in the list */
3099                         if (list_is_last(&xfer->transfer_list, &message->transfers))
3100                                 break;
3101                         xfer->cs_change = 1;
3102                 }
3103         }
3104
3105         /* Half-duplex links include original MicroWire, and ones with
3106          * only one data pin like SPI_3WIRE (switches direction) or where
3107          * either MOSI or MISO is missing.  They can also be caused by
3108          * software limitations.
3109          */
3110         if ((ctlr->flags & SPI_CONTROLLER_HALF_DUPLEX) ||
3111             (spi->mode & SPI_3WIRE)) {
3112                 unsigned flags = ctlr->flags;
3113
3114                 list_for_each_entry(xfer, &message->transfers, transfer_list) {
3115                         if (xfer->rx_buf && xfer->tx_buf)
3116                                 return -EINVAL;
3117                         if ((flags & SPI_CONTROLLER_NO_TX) && xfer->tx_buf)
3118                                 return -EINVAL;
3119                         if ((flags & SPI_CONTROLLER_NO_RX) && xfer->rx_buf)
3120                                 return -EINVAL;
3121                 }
3122         }
3123
3124         /**
3125          * Set transfer bits_per_word and max speed as spi device default if
3126          * it is not set for this transfer.
3127          * Set transfer tx_nbits and rx_nbits as single transfer default
3128          * (SPI_NBITS_SINGLE) if it is not set for this transfer.
3129          * Ensure transfer word_delay is at least as long as that required by
3130          * device itself.
3131          */
3132         message->frame_length = 0;
3133         list_for_each_entry(xfer, &message->transfers, transfer_list) {
3134                 xfer->effective_speed_hz = 0;
3135                 message->frame_length += xfer->len;
3136                 if (!xfer->bits_per_word)
3137                         xfer->bits_per_word = spi->bits_per_word;
3138
3139                 if (!xfer->speed_hz)
3140                         xfer->speed_hz = spi->max_speed_hz;
3141
3142                 if (ctlr->max_speed_hz && xfer->speed_hz > ctlr->max_speed_hz)
3143                         xfer->speed_hz = ctlr->max_speed_hz;
3144
3145                 if (__spi_validate_bits_per_word(ctlr, xfer->bits_per_word))
3146                         return -EINVAL;
3147
3148                 /*
3149                  * SPI transfer length should be multiple of SPI word size
3150                  * where SPI word size should be power-of-two multiple
3151                  */
3152                 if (xfer->bits_per_word <= 8)
3153                         w_size = 1;
3154                 else if (xfer->bits_per_word <= 16)
3155                         w_size = 2;
3156                 else
3157                         w_size = 4;
3158
3159                 /* No partial transfers accepted */
3160                 if (xfer->len % w_size)
3161                         return -EINVAL;
3162
3163                 if (xfer->speed_hz && ctlr->min_speed_hz &&
3164                     xfer->speed_hz < ctlr->min_speed_hz)
3165                         return -EINVAL;
3166
3167                 if (xfer->tx_buf && !xfer->tx_nbits)
3168                         xfer->tx_nbits = SPI_NBITS_SINGLE;
3169                 if (xfer->rx_buf && !xfer->rx_nbits)
3170                         xfer->rx_nbits = SPI_NBITS_SINGLE;
3171                 /* check transfer tx/rx_nbits:
3172                  * 1. check the value matches one of single, dual and quad
3173                  * 2. check tx/rx_nbits match the mode in spi_device
3174                  */
3175                 if (xfer->tx_buf) {
3176                         if (xfer->tx_nbits != SPI_NBITS_SINGLE &&
3177                                 xfer->tx_nbits != SPI_NBITS_DUAL &&
3178                                 xfer->tx_nbits != SPI_NBITS_QUAD)
3179                                 return -EINVAL;
3180                         if ((xfer->tx_nbits == SPI_NBITS_DUAL) &&
3181                                 !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
3182                                 return -EINVAL;
3183                         if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
3184                                 !(spi->mode & SPI_TX_QUAD))
3185                                 return -EINVAL;
3186                 }
3187                 /* check transfer rx_nbits */
3188                 if (xfer->rx_buf) {
3189                         if (xfer->rx_nbits != SPI_NBITS_SINGLE &&
3190                                 xfer->rx_nbits != SPI_NBITS_DUAL &&
3191                                 xfer->rx_nbits != SPI_NBITS_QUAD)
3192                                 return -EINVAL;
3193                         if ((xfer->rx_nbits == SPI_NBITS_DUAL) &&
3194                                 !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
3195                                 return -EINVAL;
3196                         if ((xfer->rx_nbits == SPI_NBITS_QUAD) &&
3197                                 !(spi->mode & SPI_RX_QUAD))
3198                                 return -EINVAL;
3199                 }
3200
3201                 if (xfer->word_delay_usecs < spi->word_delay_usecs)
3202                         xfer->word_delay_usecs = spi->word_delay_usecs;
3203         }
3204
3205         message->status = -EINPROGRESS;
3206
3207         return 0;
3208 }
3209
3210 static int __spi_async(struct spi_device *spi, struct spi_message *message)
3211 {
3212         struct spi_controller *ctlr = spi->controller;
3213
3214         /*
3215          * Some controllers do not support doing regular SPI transfers. Return
3216          * ENOTSUPP when this is the case.
3217          */
3218         if (!ctlr->transfer)
3219                 return -ENOTSUPP;
3220
3221         message->spi = spi;
3222
3223         SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics, spi_async);
3224         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_async);
3225
3226         trace_spi_message_submit(message);
3227
3228         return ctlr->transfer(spi, message);
3229 }
3230
3231 /**
3232  * spi_async - asynchronous SPI transfer
3233  * @spi: device with which data will be exchanged
3234  * @message: describes the data transfers, including completion callback
3235  * Context: any (irqs may be blocked, etc)
3236  *
3237  * This call may be used in_irq and other contexts which can't sleep,
3238  * as well as from task contexts which can sleep.
3239  *
3240  * The completion callback is invoked in a context which can't sleep.
3241  * Before that invocation, the value of message->status is undefined.
3242  * When the callback is issued, message->status holds either zero (to
3243  * indicate complete success) or a negative error code.  After that
3244  * callback returns, the driver which issued the transfer request may
3245  * deallocate the associated memory; it's no longer in use by any SPI
3246  * core or controller driver code.
3247  *
3248  * Note that although all messages to a spi_device are handled in
3249  * FIFO order, messages may go to different devices in other orders.
3250  * Some device might be higher priority, or have various "hard" access
3251  * time requirements, for example.
3252  *
3253  * On detection of any fault during the transfer, processing of
3254  * the entire message is aborted, and the device is deselected.
3255  * Until returning from the associated message completion callback,
3256  * no other spi_message queued to that device will be processed.
3257  * (This rule applies equally to all the synchronous transfer calls,
3258  * which are wrappers around this core asynchronous primitive.)
3259  *
3260  * Return: zero on success, else a negative error code.
3261  */
3262 int spi_async(struct spi_device *spi, struct spi_message *message)
3263 {
3264         struct spi_controller *ctlr = spi->controller;
3265         int ret;
3266         unsigned long flags;
3267
3268         ret = __spi_validate(spi, message);
3269         if (ret != 0)
3270                 return ret;
3271
3272         spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
3273
3274         if (ctlr->bus_lock_flag)
3275                 ret = -EBUSY;
3276         else
3277                 ret = __spi_async(spi, message);
3278
3279         spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3280
3281         return ret;
3282 }
3283 EXPORT_SYMBOL_GPL(spi_async);
3284
3285 /**
3286  * spi_async_locked - version of spi_async with exclusive bus usage
3287  * @spi: device with which data will be exchanged
3288  * @message: describes the data transfers, including completion callback
3289  * Context: any (irqs may be blocked, etc)
3290  *
3291  * This call may be used in_irq and other contexts which can't sleep,
3292  * as well as from task contexts which can sleep.
3293  *
3294  * The completion callback is invoked in a context which can't sleep.
3295  * Before that invocation, the value of message->status is undefined.
3296  * When the callback is issued, message->status holds either zero (to
3297  * indicate complete success) or a negative error code.  After that
3298  * callback returns, the driver which issued the transfer request may
3299  * deallocate the associated memory; it's no longer in use by any SPI
3300  * core or controller driver code.
3301  *
3302  * Note that although all messages to a spi_device are handled in
3303  * FIFO order, messages may go to different devices in other orders.
3304  * Some device might be higher priority, or have various "hard" access
3305  * time requirements, for example.
3306  *
3307  * On detection of any fault during the transfer, processing of
3308  * the entire message is aborted, and the device is deselected.
3309  * Until returning from the associated message completion callback,
3310  * no other spi_message queued to that device will be processed.
3311  * (This rule applies equally to all the synchronous transfer calls,
3312  * which are wrappers around this core asynchronous primitive.)
3313  *
3314  * Return: zero on success, else a negative error code.
3315  */
3316 int spi_async_locked(struct spi_device *spi, struct spi_message *message)
3317 {
3318         struct spi_controller *ctlr = spi->controller;
3319         int ret;
3320         unsigned long flags;
3321
3322         ret = __spi_validate(spi, message);
3323         if (ret != 0)
3324                 return ret;
3325
3326         spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
3327
3328         ret = __spi_async(spi, message);
3329
3330         spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3331
3332         return ret;
3333
3334 }
3335 EXPORT_SYMBOL_GPL(spi_async_locked);
3336
3337 /*-------------------------------------------------------------------------*/
3338
3339 /* Utility methods for SPI protocol drivers, layered on
3340  * top of the core.  Some other utility methods are defined as
3341  * inline functions.
3342  */
3343
3344 static void spi_complete(void *arg)
3345 {
3346         complete(arg);
3347 }
3348
3349 static int __spi_sync(struct spi_device *spi, struct spi_message *message)
3350 {
3351         DECLARE_COMPLETION_ONSTACK(done);
3352         int status;
3353         struct spi_controller *ctlr = spi->controller;
3354         unsigned long flags;
3355
3356         status = __spi_validate(spi, message);
3357         if (status != 0)
3358                 return status;
3359
3360         message->complete = spi_complete;
3361         message->context = &done;
3362         message->spi = spi;
3363
3364         SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics, spi_sync);
3365         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_sync);
3366
3367         /* If we're not using the legacy transfer method then we will
3368          * try to transfer in the calling context so special case.
3369          * This code would be less tricky if we could remove the
3370          * support for driver implemented message queues.
3371          */
3372         if (ctlr->transfer == spi_queued_transfer) {
3373                 spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
3374
3375                 trace_spi_message_submit(message);
3376
3377                 status = __spi_queued_transfer(spi, message, false);
3378
3379                 spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3380         } else {
3381                 status = spi_async_locked(spi, message);
3382         }
3383
3384         if (status == 0) {
3385                 /* Push out the messages in the calling context if we
3386                  * can.
3387                  */
3388                 if (ctlr->transfer == spi_queued_transfer) {
3389                         SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics,
3390                                                        spi_sync_immediate);
3391                         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics,
3392                                                        spi_sync_immediate);
3393                         __spi_pump_messages(ctlr, false);
3394                 }
3395
3396                 wait_for_completion(&done);
3397                 status = message->status;
3398         }
3399         message->context = NULL;
3400         return status;
3401 }
3402
3403 /**
3404  * spi_sync - blocking/synchronous SPI data transfers
3405  * @spi: device with which data will be exchanged
3406  * @message: describes the data transfers
3407  * Context: can sleep
3408  *
3409  * This call may only be used from a context that may sleep.  The sleep
3410  * is non-interruptible, and has no timeout.  Low-overhead controller
3411  * drivers may DMA directly into and out of the message buffers.
3412  *
3413  * Note that the SPI device's chip select is active during the message,
3414  * and then is normally disabled between messages.  Drivers for some
3415  * frequently-used devices may want to minimize costs of selecting a chip,
3416  * by leaving it selected in anticipation that the next message will go
3417  * to the same chip.  (That may increase power usage.)
3418  *
3419  * Also, the caller is guaranteeing that the memory associated with the
3420  * message will not be freed before this call returns.
3421  *
3422  * Return: zero on success, else a negative error code.
3423  */
3424 int spi_sync(struct spi_device *spi, struct spi_message *message)
3425 {
3426         int ret;
3427
3428         mutex_lock(&spi->controller->bus_lock_mutex);
3429         ret = __spi_sync(spi, message);
3430         mutex_unlock(&spi->controller->bus_lock_mutex);
3431
3432         return ret;
3433 }
3434 EXPORT_SYMBOL_GPL(spi_sync);
3435
3436 /**
3437  * spi_sync_locked - version of spi_sync with exclusive bus usage
3438  * @spi: device with which data will be exchanged
3439  * @message: describes the data transfers
3440  * Context: can sleep
3441  *
3442  * This call may only be used from a context that may sleep.  The sleep
3443  * is non-interruptible, and has no timeout.  Low-overhead controller
3444  * drivers may DMA directly into and out of the message buffers.
3445  *
3446  * This call should be used by drivers that require exclusive access to the
3447  * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
3448  * be released by a spi_bus_unlock call when the exclusive access is over.
3449  *
3450  * Return: zero on success, else a negative error code.
3451  */
3452 int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
3453 {
3454         return __spi_sync(spi, message);
3455 }
3456 EXPORT_SYMBOL_GPL(spi_sync_locked);
3457
3458 /**
3459  * spi_bus_lock - obtain a lock for exclusive SPI bus usage
3460  * @ctlr: SPI bus master that should be locked for exclusive bus access
3461  * Context: can sleep
3462  *
3463  * This call may only be used from a context that may sleep.  The sleep
3464  * is non-interruptible, and has no timeout.
3465  *
3466  * This call should be used by drivers that require exclusive access to the
3467  * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
3468  * exclusive access is over. Data transfer must be done by spi_sync_locked
3469  * and spi_async_locked calls when the SPI bus lock is held.
3470  *
3471  * Return: always zero.
3472  */
3473 int spi_bus_lock(struct spi_controller *ctlr)
3474 {
3475         unsigned long flags;
3476
3477         mutex_lock(&ctlr->bus_lock_mutex);
3478
3479         spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
3480         ctlr->bus_lock_flag = 1;
3481         spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3482
3483         /* mutex remains locked until spi_bus_unlock is called */
3484
3485         return 0;
3486 }
3487 EXPORT_SYMBOL_GPL(spi_bus_lock);
3488
3489 /**
3490  * spi_bus_unlock - release the lock for exclusive SPI bus usage
3491  * @ctlr: SPI bus master that was locked for exclusive bus access
3492  * Context: can sleep
3493  *
3494  * This call may only be used from a context that may sleep.  The sleep
3495  * is non-interruptible, and has no timeout.
3496  *
3497  * This call releases an SPI bus lock previously obtained by an spi_bus_lock
3498  * call.
3499  *
3500  * Return: always zero.
3501  */
3502 int spi_bus_unlock(struct spi_controller *ctlr)
3503 {
3504         ctlr->bus_lock_flag = 0;
3505
3506         mutex_unlock(&ctlr->bus_lock_mutex);
3507
3508         return 0;
3509 }
3510 EXPORT_SYMBOL_GPL(spi_bus_unlock);
3511
3512 /* portable code must never pass more than 32 bytes */
3513 #define SPI_BUFSIZ      max(32, SMP_CACHE_BYTES)
3514
3515 static u8       *buf;
3516
3517 /**
3518  * spi_write_then_read - SPI synchronous write followed by read
3519  * @spi: device with which data will be exchanged
3520  * @txbuf: data to be written (need not be dma-safe)
3521  * @n_tx: size of txbuf, in bytes
3522  * @rxbuf: buffer into which data will be read (need not be dma-safe)
3523  * @n_rx: size of rxbuf, in bytes
3524  * Context: can sleep
3525  *
3526  * This performs a half duplex MicroWire style transaction with the
3527  * device, sending txbuf and then reading rxbuf.  The return value
3528  * is zero for success, else a negative errno status code.
3529  * This call may only be used from a context that may sleep.
3530  *
3531  * Parameters to this routine are always copied using a small buffer;
3532  * portable code should never use this for more than 32 bytes.
3533  * Performance-sensitive or bulk transfer code should instead use
3534  * spi_{async,sync}() calls with dma-safe buffers.
3535  *
3536  * Return: zero on success, else a negative error code.
3537  */
3538 int spi_write_then_read(struct spi_device *spi,
3539                 const void *txbuf, unsigned n_tx,
3540                 void *rxbuf, unsigned n_rx)
3541 {
3542         static DEFINE_MUTEX(lock);
3543
3544         int                     status;
3545         struct spi_message      message;
3546         struct spi_transfer     x[2];
3547         u8                      *local_buf;
3548
3549         /* Use preallocated DMA-safe buffer if we can.  We can't avoid
3550          * copying here, (as a pure convenience thing), but we can
3551          * keep heap costs out of the hot path unless someone else is
3552          * using the pre-allocated buffer or the transfer is too large.
3553          */
3554         if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) {
3555                 local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx),
3556                                     GFP_KERNEL | GFP_DMA);
3557                 if (!local_buf)
3558                         return -ENOMEM;
3559         } else {
3560                 local_buf = buf;
3561         }
3562
3563         spi_message_init(&message);
3564         memset(x, 0, sizeof(x));
3565         if (n_tx) {
3566                 x[0].len = n_tx;
3567                 spi_message_add_tail(&x[0], &message);
3568         }
3569         if (n_rx) {
3570                 x[1].len = n_rx;
3571                 spi_message_add_tail(&x[1], &message);
3572         }
3573
3574         memcpy(local_buf, txbuf, n_tx);
3575         x[0].tx_buf = local_buf;
3576         x[1].rx_buf = local_buf + n_tx;
3577
3578         /* do the i/o */
3579         status = spi_sync(spi, &message);
3580         if (status == 0)
3581                 memcpy(rxbuf, x[1].rx_buf, n_rx);
3582
3583         if (x[0].tx_buf == buf)
3584                 mutex_unlock(&lock);
3585         else
3586                 kfree(local_buf);
3587
3588         return status;
3589 }
3590 EXPORT_SYMBOL_GPL(spi_write_then_read);
3591
3592 /*-------------------------------------------------------------------------*/
3593
3594 #if IS_ENABLED(CONFIG_OF)
3595 static int __spi_of_device_match(struct device *dev, void *data)
3596 {
3597         return dev->of_node == data;
3598 }
3599
3600 /* must call put_device() when done with returned spi_device device */
3601 struct spi_device *of_find_spi_device_by_node(struct device_node *node)
3602 {
3603         struct device *dev = bus_find_device(&spi_bus_type, NULL, node,
3604                                                 __spi_of_device_match);
3605         return dev ? to_spi_device(dev) : NULL;
3606 }
3607 EXPORT_SYMBOL_GPL(of_find_spi_device_by_node);
3608 #endif /* IS_ENABLED(CONFIG_OF) */
3609
3610 #if IS_ENABLED(CONFIG_OF_DYNAMIC)
3611 static int __spi_of_controller_match(struct device *dev, const void *data)
3612 {
3613         return dev->of_node == data;
3614 }
3615
3616 /* the spi controllers are not using spi_bus, so we find it with another way */
3617 static struct spi_controller *of_find_spi_controller_by_node(struct device_node *node)
3618 {
3619         struct device *dev;
3620
3621         dev = class_find_device(&spi_master_class, NULL, node,
3622                                 __spi_of_controller_match);
3623         if (!dev && IS_ENABLED(CONFIG_SPI_SLAVE))
3624                 dev = class_find_device(&spi_slave_class, NULL, node,
3625                                         __spi_of_controller_match);
3626         if (!dev)
3627                 return NULL;
3628
3629         /* reference got in class_find_device */
3630         return container_of(dev, struct spi_controller, dev);
3631 }
3632
3633 static int of_spi_notify(struct notifier_block *nb, unsigned long action,
3634                          void *arg)
3635 {
3636         struct of_reconfig_data *rd = arg;
3637         struct spi_controller *ctlr;
3638         struct spi_device *spi;
3639
3640         switch (of_reconfig_get_state_change(action, arg)) {
3641         case OF_RECONFIG_CHANGE_ADD:
3642                 ctlr = of_find_spi_controller_by_node(rd->dn->parent);
3643                 if (ctlr == NULL)
3644                         return NOTIFY_OK;       /* not for us */
3645
3646                 if (of_node_test_and_set_flag(rd->dn, OF_POPULATED)) {
3647                         put_device(&ctlr->dev);
3648                         return NOTIFY_OK;
3649                 }
3650
3651                 spi = of_register_spi_device(ctlr, rd->dn);
3652                 put_device(&ctlr->dev);
3653
3654                 if (IS_ERR(spi)) {
3655                         pr_err("%s: failed to create for '%pOF'\n",
3656                                         __func__, rd->dn);
3657                         of_node_clear_flag(rd->dn, OF_POPULATED);
3658                         return notifier_from_errno(PTR_ERR(spi));
3659                 }
3660                 break;
3661
3662         case OF_RECONFIG_CHANGE_REMOVE:
3663                 /* already depopulated? */
3664                 if (!of_node_check_flag(rd->dn, OF_POPULATED))
3665                         return NOTIFY_OK;
3666
3667                 /* find our device by node */
3668                 spi = of_find_spi_device_by_node(rd->dn);
3669                 if (spi == NULL)
3670                         return NOTIFY_OK;       /* no? not meant for us */
3671
3672                 /* unregister takes one ref away */
3673                 spi_unregister_device(spi);
3674
3675                 /* and put the reference of the find */
3676                 put_device(&spi->dev);
3677                 break;
3678         }
3679
3680         return NOTIFY_OK;
3681 }
3682
3683 static struct notifier_block spi_of_notifier = {
3684         .notifier_call = of_spi_notify,
3685 };
3686 #else /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
3687 extern struct notifier_block spi_of_notifier;
3688 #endif /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
3689
3690 #if IS_ENABLED(CONFIG_ACPI)
3691 static int spi_acpi_controller_match(struct device *dev, const void *data)
3692 {
3693         return ACPI_COMPANION(dev->parent) == data;
3694 }
3695
3696 static int spi_acpi_device_match(struct device *dev, void *data)
3697 {
3698         return ACPI_COMPANION(dev) == data;
3699 }
3700
3701 static struct spi_controller *acpi_spi_find_controller_by_adev(struct acpi_device *adev)
3702 {
3703         struct device *dev;
3704
3705         dev = class_find_device(&spi_master_class, NULL, adev,
3706                                 spi_acpi_controller_match);
3707         if (!dev && IS_ENABLED(CONFIG_SPI_SLAVE))
3708                 dev = class_find_device(&spi_slave_class, NULL, adev,
3709                                         spi_acpi_controller_match);
3710         if (!dev)
3711                 return NULL;
3712
3713         return container_of(dev, struct spi_controller, dev);
3714 }
3715
3716 static struct spi_device *acpi_spi_find_device_by_adev(struct acpi_device *adev)
3717 {
3718         struct device *dev;
3719
3720         dev = bus_find_device(&spi_bus_type, NULL, adev, spi_acpi_device_match);
3721
3722         return dev ? to_spi_device(dev) : NULL;
3723 }
3724
3725 static int acpi_spi_notify(struct notifier_block *nb, unsigned long value,
3726                            void *arg)
3727 {
3728         struct acpi_device *adev = arg;
3729         struct spi_controller *ctlr;
3730         struct spi_device *spi;
3731
3732         switch (value) {
3733         case ACPI_RECONFIG_DEVICE_ADD:
3734                 ctlr = acpi_spi_find_controller_by_adev(adev->parent);
3735                 if (!ctlr)
3736                         break;
3737
3738                 acpi_register_spi_device(ctlr, adev);
3739                 put_device(&ctlr->dev);
3740                 break;
3741         case ACPI_RECONFIG_DEVICE_REMOVE:
3742                 if (!acpi_device_enumerated(adev))
3743                         break;
3744
3745                 spi = acpi_spi_find_device_by_adev(adev);
3746                 if (!spi)
3747                         break;
3748
3749                 spi_unregister_device(spi);
3750                 put_device(&spi->dev);
3751                 break;
3752         }
3753
3754         return NOTIFY_OK;
3755 }
3756
3757 static struct notifier_block spi_acpi_notifier = {
3758         .notifier_call = acpi_spi_notify,
3759 };
3760 #else
3761 extern struct notifier_block spi_acpi_notifier;
3762 #endif
3763
3764 static int __init spi_init(void)
3765 {
3766         int     status;
3767
3768         buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
3769         if (!buf) {
3770                 status = -ENOMEM;
3771                 goto err0;
3772         }
3773
3774         status = bus_register(&spi_bus_type);
3775         if (status < 0)
3776                 goto err1;
3777
3778         status = class_register(&spi_master_class);
3779         if (status < 0)
3780                 goto err2;
3781
3782         if (IS_ENABLED(CONFIG_SPI_SLAVE)) {
3783                 status = class_register(&spi_slave_class);
3784                 if (status < 0)
3785                         goto err3;
3786         }
3787
3788         if (IS_ENABLED(CONFIG_OF_DYNAMIC))
3789                 WARN_ON(of_reconfig_notifier_register(&spi_of_notifier));
3790         if (IS_ENABLED(CONFIG_ACPI))
3791                 WARN_ON(acpi_reconfig_notifier_register(&spi_acpi_notifier));
3792
3793         return 0;
3794
3795 err3:
3796         class_unregister(&spi_master_class);
3797 err2:
3798         bus_unregister(&spi_bus_type);
3799 err1:
3800         kfree(buf);
3801         buf = NULL;
3802 err0:
3803         return status;
3804 }
3805
3806 /* board_info is normally registered in arch_initcall(),
3807  * but even essential drivers wait till later
3808  *
3809  * REVISIT only boardinfo really needs static linking. the rest (device and
3810  * driver registration) _could_ be dynamically linked (modular) ... costs
3811  * include needing to have boardinfo data structures be much more public.
3812  */
3813 postcore_initcall(spi_init);