drivers/spi/spi.c

   1 /*
   2  * SPI init/core code
   3  *
   4  * Copyright (C) 2005 David Brownell
   5  * Copyright (C) 2008 Secret Lab Technologies Ltd.
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  */
  17
  18 #include <linux/kernel.h>
  19 #include <linux/device.h>
  20 #include <linux/init.h>
  21 #include <linux/cache.h>
  22 #include <linux/dma-mapping.h>
  23 #include <linux/dmaengine.h>
  24 #include <linux/mutex.h>
  25 #include <linux/of_device.h>
  26 #include <linux/of_irq.h>
  27 #include <linux/clk/clk-conf.h>
  28 #include <linux/slab.h>
  29 #include <linux/mod_devicetable.h>
  30 #include <linux/spi/spi.h>
  31 #include <linux/of_gpio.h>
  32 #include <linux/pm_runtime.h>
  33 #include <linux/pm_domain.h>
  34 #include <linux/export.h>
  35 #include <linux/sched/rt.h>
  36 #include <linux/delay.h>
  37 #include <linux/kthread.h>
  38 #include <linux/ioport.h>
  39 #include <linux/acpi.h>
  40
  41 #define CREATE_TRACE_POINTS
  42 #include <trace/events/spi.h>
  43
  44 static void spidev_release(struct device *dev)
  45 {
  46         struct spi_device       *spi = to_spi_device(dev);
  47
  48         /* spi masters may cleanup for released devices */
  49         if (spi->master->cleanup)
  50                 spi->master->cleanup(spi);
  51
  52         spi_master_put(spi->master);
  53         kfree(spi);
  54 }
  55
  56 static ssize_t
  57 modalias_show(struct device *dev, struct device_attribute *a, char *buf)
  58 {
  59         const struct spi_device *spi = to_spi_device(dev);
  60         int len;
  61
  62         len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1);
  63         if (len != -ENODEV)
  64                 return len;
  65
  66         return sprintf(buf, "%s%s\n", SPI_MODULE_PREFIX, spi->modalias);
  67 }
  68 static DEVICE_ATTR_RO(modalias);
  69
  70 #define SPI_STATISTICS_ATTRS(field, file)                               \
  71 static ssize_t spi_master_##field##_show(struct device *dev,            \
  72                                          struct device_attribute *attr, \
  73                                          char *buf)                     \
  74 {                                                                       \
  75         struct spi_master *master = container_of(dev,                   \
  76                                                  struct spi_master, dev); \
  77         return spi_statistics_##field##_show(&master->statistics, buf); \
  78 }                                                                       \
  79 static struct device_attribute dev_attr_spi_master_##field = {          \
  80         .attr = { .name = file, .mode = S_IRUGO },                      \
  81         .show = spi_master_##field##_show,                              \
  82 };                                                                      \
  83 static ssize_t spi_device_##field##_show(struct device *dev,            \
  84                                          struct device_attribute *attr, \
  85                                         char *buf)                      \
  86 {                                                                       \
  87         struct spi_device *spi = to_spi_device(dev);                    \
  88         return spi_statistics_##field##_show(&spi->statistics, buf);    \
  89 }                                                                       \
  90 static struct device_attribute dev_attr_spi_device_##field = {          \
  91         .attr = { .name = file, .mode = S_IRUGO },                      \
  92         .show = spi_device_##field##_show,                              \
  93 }
  94
  95 #define SPI_STATISTICS_SHOW_NAME(name, file, field, format_string)      \
  96 static ssize_t spi_statistics_##name##_show(struct spi_statistics *stat, \
  97                                             char *buf)                  \
  98 {                                                                       \
  99         unsigned long flags;                                            \
 100         ssize_t len;                                                    \
 101         spin_lock_irqsave(&stat->lock, flags);                          \
 102         len = sprintf(buf, format_string, stat->field);                 \
 103         spin_unlock_irqrestore(&stat->lock, flags);                     \
 104         return len;                                                     \
 105 }                                                                       \
 106 SPI_STATISTICS_ATTRS(name, file)
 107
 108 #define SPI_STATISTICS_SHOW(field, format_string)                       \
 109         SPI_STATISTICS_SHOW_NAME(field, __stringify(field),             \
 110                                  field, format_string)
 111
 112 SPI_STATISTICS_SHOW(messages, "%lu");
 113 SPI_STATISTICS_SHOW(transfers, "%lu");
 114 SPI_STATISTICS_SHOW(errors, "%lu");
 115 SPI_STATISTICS_SHOW(timedout, "%lu");
 116
 117 SPI_STATISTICS_SHOW(spi_sync, "%lu");
 118 SPI_STATISTICS_SHOW(spi_sync_immediate, "%lu");
 119 SPI_STATISTICS_SHOW(spi_async, "%lu");
 120
 121 SPI_STATISTICS_SHOW(bytes, "%llu");
 122 SPI_STATISTICS_SHOW(bytes_rx, "%llu");
 123 SPI_STATISTICS_SHOW(bytes_tx, "%llu");
 124
 125 #define SPI_STATISTICS_TRANSFER_BYTES_HISTO(index, number)              \
 126         SPI_STATISTICS_SHOW_NAME(transfer_bytes_histo##index,           \
 127                                  "transfer_bytes_histo_" number,        \
 128                                  transfer_bytes_histo[index],  "%lu")
 129 SPI_STATISTICS_TRANSFER_BYTES_HISTO(0,  "0-1");
 130 SPI_STATISTICS_TRANSFER_BYTES_HISTO(1,  "2-3");
 131 SPI_STATISTICS_TRANSFER_BYTES_HISTO(2,  "4-7");
 132 SPI_STATISTICS_TRANSFER_BYTES_HISTO(3,  "8-15");
 133 SPI_STATISTICS_TRANSFER_BYTES_HISTO(4,  "16-31");
 134 SPI_STATISTICS_TRANSFER_BYTES_HISTO(5,  "32-63");
 135 SPI_STATISTICS_TRANSFER_BYTES_HISTO(6,  "64-127");
 136 SPI_STATISTICS_TRANSFER_BYTES_HISTO(7,  "128-255");
 137 SPI_STATISTICS_TRANSFER_BYTES_HISTO(8,  "256-511");
 138 SPI_STATISTICS_TRANSFER_BYTES_HISTO(9,  "512-1023");
 139 SPI_STATISTICS_TRANSFER_BYTES_HISTO(10, "1024-2047");
 140 SPI_STATISTICS_TRANSFER_BYTES_HISTO(11, "2048-4095");
 141 SPI_STATISTICS_TRANSFER_BYTES_HISTO(12, "4096-8191");
 142 SPI_STATISTICS_TRANSFER_BYTES_HISTO(13, "8192-16383");
 143 SPI_STATISTICS_TRANSFER_BYTES_HISTO(14, "16384-32767");
 144 SPI_STATISTICS_TRANSFER_BYTES_HISTO(15, "32768-65535");
 145 SPI_STATISTICS_TRANSFER_BYTES_HISTO(16, "65536+");
 146
 147 SPI_STATISTICS_SHOW(transfers_split_maxsize, "%lu");
 148
 149 static struct attribute *spi_dev_attrs[] = {
 150         &dev_attr_modalias.attr,
 151         NULL,
 152 };
 153
 154 static const struct attribute_group spi_dev_group = {
 155         .attrs  = spi_dev_attrs,
 156 };
 157
 158 static struct attribute *spi_device_statistics_attrs[] = {
 159         &dev_attr_spi_device_messages.attr,
 160         &dev_attr_spi_device_transfers.attr,
 161         &dev_attr_spi_device_errors.attr,
 162         &dev_attr_spi_device_timedout.attr,
 163         &dev_attr_spi_device_spi_sync.attr,
 164         &dev_attr_spi_device_spi_sync_immediate.attr,
 165         &dev_attr_spi_device_spi_async.attr,
 166         &dev_attr_spi_device_bytes.attr,
 167         &dev_attr_spi_device_bytes_rx.attr,
 168         &dev_attr_spi_device_bytes_tx.attr,
 169         &dev_attr_spi_device_transfer_bytes_histo0.attr,
 170         &dev_attr_spi_device_transfer_bytes_histo1.attr,
 171         &dev_attr_spi_device_transfer_bytes_histo2.attr,
 172         &dev_attr_spi_device_transfer_bytes_histo3.attr,
 173         &dev_attr_spi_device_transfer_bytes_histo4.attr,
 174         &dev_attr_spi_device_transfer_bytes_histo5.attr,
 175         &dev_attr_spi_device_transfer_bytes_histo6.attr,
 176         &dev_attr_spi_device_transfer_bytes_histo7.attr,
 177         &dev_attr_spi_device_transfer_bytes_histo8.attr,
 178         &dev_attr_spi_device_transfer_bytes_histo9.attr,
 179         &dev_attr_spi_device_transfer_bytes_histo10.attr,
 180         &dev_attr_spi_device_transfer_bytes_histo11.attr,
 181         &dev_attr_spi_device_transfer_bytes_histo12.attr,
 182         &dev_attr_spi_device_transfer_bytes_histo13.attr,
 183         &dev_attr_spi_device_transfer_bytes_histo14.attr,
 184         &dev_attr_spi_device_transfer_bytes_histo15.attr,
 185         &dev_attr_spi_device_transfer_bytes_histo16.attr,
 186         &dev_attr_spi_device_transfers_split_maxsize.attr,
 187         NULL,
 188 };
 189
 190 static const struct attribute_group spi_device_statistics_group = {
 191         .name  = "statistics",
 192         .attrs  = spi_device_statistics_attrs,
 193 };
 194
 195 static const struct attribute_group *spi_dev_groups[] = {
 196         &spi_dev_group,
 197         &spi_device_statistics_group,
 198         NULL,
 199 };
 200
 201 static struct attribute *spi_master_statistics_attrs[] = {
 202         &dev_attr_spi_master_messages.attr,
 203         &dev_attr_spi_master_transfers.attr,
 204         &dev_attr_spi_master_errors.attr,
 205         &dev_attr_spi_master_timedout.attr,
 206         &dev_attr_spi_master_spi_sync.attr,
 207         &dev_attr_spi_master_spi_sync_immediate.attr,
 208         &dev_attr_spi_master_spi_async.attr,
 209         &dev_attr_spi_master_bytes.attr,
 210         &dev_attr_spi_master_bytes_rx.attr,
 211         &dev_attr_spi_master_bytes_tx.attr,
 212         &dev_attr_spi_master_transfer_bytes_histo0.attr,
 213         &dev_attr_spi_master_transfer_bytes_histo1.attr,
 214         &dev_attr_spi_master_transfer_bytes_histo2.attr,
 215         &dev_attr_spi_master_transfer_bytes_histo3.attr,
 216         &dev_attr_spi_master_transfer_bytes_histo4.attr,
 217         &dev_attr_spi_master_transfer_bytes_histo5.attr,
 218         &dev_attr_spi_master_transfer_bytes_histo6.attr,
 219         &dev_attr_spi_master_transfer_bytes_histo7.attr,
 220         &dev_attr_spi_master_transfer_bytes_histo8.attr,
 221         &dev_attr_spi_master_transfer_bytes_histo9.attr,
 222         &dev_attr_spi_master_transfer_bytes_histo10.attr,
 223         &dev_attr_spi_master_transfer_bytes_histo11.attr,
 224         &dev_attr_spi_master_transfer_bytes_histo12.attr,
 225         &dev_attr_spi_master_transfer_bytes_histo13.attr,
 226         &dev_attr_spi_master_transfer_bytes_histo14.attr,
 227         &dev_attr_spi_master_transfer_bytes_histo15.attr,
 228         &dev_attr_spi_master_transfer_bytes_histo16.attr,
 229         &dev_attr_spi_master_transfers_split_maxsize.attr,
 230         NULL,
 231 };
 232
 233 static const struct attribute_group spi_master_statistics_group = {
 234         .name  = "statistics",
 235         .attrs  = spi_master_statistics_attrs,
 236 };
 237
 238 static const struct attribute_group *spi_master_groups[] = {
 239         &spi_master_statistics_group,
 240         NULL,
 241 };
 242
 243 void spi_statistics_add_transfer_stats(struct spi_statistics *stats,
 244                                        struct spi_transfer *xfer,
 245                                        struct spi_master *master)
 246 {
 247         unsigned long flags;
 248         int l2len = min(fls(xfer->len), SPI_STATISTICS_HISTO_SIZE) - 1;
 249
 250         if (l2len < 0)
 251                 l2len = 0;
 252
 253         spin_lock_irqsave(&stats->lock, flags);
 254
 255         stats->transfers++;
 256         stats->transfer_bytes_histo[l2len]++;
 257
 258         stats->bytes += xfer->len;
 259         if ((xfer->tx_buf) &&
 260             (xfer->tx_buf != master->dummy_tx))
 261                 stats->bytes_tx += xfer->len;
 262         if ((xfer->rx_buf) &&
 263             (xfer->rx_buf != master->dummy_rx))
 264                 stats->bytes_rx += xfer->len;
 265
 266         spin_unlock_irqrestore(&stats->lock, flags);
 267 }
 268 EXPORT_SYMBOL_GPL(spi_statistics_add_transfer_stats);
 269
 270 /* modalias support makes "modprobe $MODALIAS" new-style hotplug work,
 271  * and the sysfs version makes coldplug work too.
 272  */
 273
 274 static const struct spi_device_id *spi_match_id(const struct spi_device_id *id,
 275                                                 const struct spi_device *sdev)
 276 {
 277         while (id->name[0]) {
 278                 if (!strcmp(sdev->modalias, id->name))
 279                         return id;
 280                 id++;
 281         }
 282         return NULL;
 283 }
 284
 285 const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev)
 286 {
 287         const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver);
 288
 289         return spi_match_id(sdrv->id_table, sdev);
 290 }
 291 EXPORT_SYMBOL_GPL(spi_get_device_id);
 292
 293 static int spi_match_device(struct device *dev, struct device_driver *drv)
 294 {
 295         const struct spi_device *spi = to_spi_device(dev);
 296         const struct spi_driver *sdrv = to_spi_driver(drv);
 297
 298         /* Attempt an OF style match */
 299         if (of_driver_match_device(dev, drv))
 300                 return 1;
 301
 302         /* Then try ACPI */
 303         if (acpi_driver_match_device(dev, drv))
 304                 return 1;
 305
 306         if (sdrv->id_table)
 307                 return !!spi_match_id(sdrv->id_table, spi);
 308
 309         return strcmp(spi->modalias, drv->name) == 0;
 310 }
 311
 312 static int spi_uevent(struct device *dev, struct kobj_uevent_env *env)
 313 {
 314         const struct spi_device         *spi = to_spi_device(dev);
 315         int rc;
 316
 317         rc = acpi_device_uevent_modalias(dev, env);
 318         if (rc != -ENODEV)
 319                 return rc;
 320
 321         add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias);
 322         return 0;
 323 }
 324
 325 struct bus_type spi_bus_type = {
 326         .name           = "spi",
 327         .dev_groups     = spi_dev_groups,
 328         .match          = spi_match_device,
 329         .uevent         = spi_uevent,
 330 };
 331 EXPORT_SYMBOL_GPL(spi_bus_type);
 332
 333
 334 static int spi_drv_probe(struct device *dev)
 335 {
 336         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
 337         struct spi_device               *spi = to_spi_device(dev);
 338         int ret;
 339
 340         ret = of_clk_set_defaults(dev->of_node, false);
 341         if (ret)
 342                 return ret;
 343
 344         if (dev->of_node) {
 345                 spi->irq = of_irq_get(dev->of_node, 0);
 346                 if (spi->irq == -EPROBE_DEFER)
 347                         return -EPROBE_DEFER;
 348                 if (spi->irq < 0)
 349                         spi->irq = 0;
 350         }
 351
 352         ret = dev_pm_domain_attach(dev, true);
 353         if (ret != -EPROBE_DEFER) {
 354                 ret = sdrv->probe(spi);
 355                 if (ret)
 356                         dev_pm_domain_detach(dev, true);
 357         }
 358
 359         return ret;
 360 }
 361
 362 static int spi_drv_remove(struct device *dev)
 363 {
 364         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
 365         int ret;
 366
 367         ret = sdrv->remove(to_spi_device(dev));
 368         dev_pm_domain_detach(dev, true);
 369
 370         return ret;
 371 }
 372
 373 static void spi_drv_shutdown(struct device *dev)
 374 {
 375         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
 376
 377         sdrv->shutdown(to_spi_device(dev));
 378 }
 379
 380 /**
 381  * __spi_register_driver - register a SPI driver
 382  * @owner: owner module of the driver to register
 383  * @sdrv: the driver to register
 384  * Context: can sleep
 385  *
 386  * Return: zero on success, else a negative error code.
 387  */
 388 int __spi_register_driver(struct module *owner, struct spi_driver *sdrv)
 389 {
 390         sdrv->driver.owner = owner;
 391         sdrv->driver.bus = &spi_bus_type;
 392         if (sdrv->probe)
 393                 sdrv->driver.probe = spi_drv_probe;
 394         if (sdrv->remove)
 395                 sdrv->driver.remove = spi_drv_remove;
 396         if (sdrv->shutdown)
 397                 sdrv->driver.shutdown = spi_drv_shutdown;
 398         return driver_register(&sdrv->driver);
 399 }
 400 EXPORT_SYMBOL_GPL(__spi_register_driver);
 401
 402 /*-------------------------------------------------------------------------*/
 403
 404 /* SPI devices should normally not be created by SPI device drivers; that
 405  * would make them board-specific.  Similarly with SPI master drivers.
 406  * Device registration normally goes into like arch/.../mach.../board-YYY.c
 407  * with other readonly (flashable) information about mainboard devices.
 408  */
 409
 410 struct boardinfo {
 411         struct list_head        list;
 412         struct spi_board_info   board_info;
 413 };
 414
 415 static LIST_HEAD(board_list);
 416 static LIST_HEAD(spi_master_list);
 417
 418 /*
 419  * Used to protect add/del opertion for board_info list and
 420  * spi_master list, and their matching process
 421  */
 422 static DEFINE_MUTEX(board_lock);
 423
 424 /**
 425  * spi_alloc_device - Allocate a new SPI device
 426  * @master: Controller to which device is connected
 427  * Context: can sleep
 428  *
 429  * Allows a driver to allocate and initialize a spi_device without
 430  * registering it immediately.  This allows a driver to directly
 431  * fill the spi_device with device parameters before calling
 432  * spi_add_device() on it.
 433  *
 434  * Caller is responsible to call spi_add_device() on the returned
 435  * spi_device structure to add it to the SPI master.  If the caller
 436  * needs to discard the spi_device without adding it, then it should
 437  * call spi_dev_put() on it.
 438  *
 439  * Return: a pointer to the new device, or NULL.
 440  */
 441 struct spi_device *spi_alloc_device(struct spi_master *master)
 442 {
 443         struct spi_device       *spi;
 444
 445         if (!spi_master_get(master))
 446                 return NULL;
 447
 448         spi = kzalloc(sizeof(*spi), GFP_KERNEL);
 449         if (!spi) {
 450                 spi_master_put(master);
 451                 return NULL;
 452         }
 453
 454         spi->master = master;
 455         spi->dev.parent = &master->dev;
 456         spi->dev.bus = &spi_bus_type;
 457         spi->dev.release = spidev_release;
 458         spi->cs_gpio = -ENOENT;
 459
 460         spin_lock_init(&spi->statistics.lock);
 461
 462         device_initialize(&spi->dev);
 463         return spi;
 464 }
 465 EXPORT_SYMBOL_GPL(spi_alloc_device);
 466
 467 static void spi_dev_set_name(struct spi_device *spi)
 468 {
 469         struct acpi_device *adev = ACPI_COMPANION(&spi->dev);
 470
 471         if (adev) {
 472                 dev_set_name(&spi->dev, "spi-%s", acpi_dev_name(adev));
 473                 return;
 474         }
 475
 476         dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->master->dev),
 477                      spi->chip_select);
 478 }
 479
 480 static int spi_dev_check(struct device *dev, void *data)
 481 {
 482         struct spi_device *spi = to_spi_device(dev);
 483         struct spi_device *new_spi = data;
 484
 485         if (spi->master == new_spi->master &&
 486             spi->chip_select == new_spi->chip_select)
 487                 return -EBUSY;
 488         return 0;
 489 }
 490
 491 /**
 492  * spi_add_device - Add spi_device allocated with spi_alloc_device
 493  * @spi: spi_device to register
 494  *
 495  * Companion function to spi_alloc_device.  Devices allocated with
 496  * spi_alloc_device can be added onto the spi bus with this function.
 497  *
 498  * Return: 0 on success; negative errno on failure
 499  */
 500 int spi_add_device(struct spi_device *spi)
 501 {
 502         static DEFINE_MUTEX(spi_add_lock);
 503         struct spi_master *master = spi->master;
 504         struct device *dev = master->dev.parent;
 505         int status;
 506
 507         /* Chipselects are numbered 0..max; validate. */
 508         if (spi->chip_select >= master->num_chipselect) {
 509                 dev_err(dev, "cs%d >= max %d\n",
 510                         spi->chip_select,
 511                         master->num_chipselect);
 512                 return -EINVAL;
 513         }
 514
 515         /* Set the bus ID string */
 516         spi_dev_set_name(spi);
 517
 518         /* We need to make sure there's no other device with this
 519          * chipselect **BEFORE** we call setup(), else we'll trash
 520          * its configuration.  Lock against concurrent add() calls.
 521          */
 522         mutex_lock(&spi_add_lock);
 523
 524         status = bus_for_each_dev(&spi_bus_type, NULL, spi, spi_dev_check);
 525         if (status) {
 526                 dev_err(dev, "chipselect %d already in use\n",
 527                                 spi->chip_select);
 528                 goto done;
 529         }
 530
 531         if (master->cs_gpios)
 532                 spi->cs_gpio = master->cs_gpios[spi->chip_select];
 533
 534         /* Drivers may modify this initial i/o setup, but will
 535          * normally rely on the device being setup.  Devices
 536          * using SPI_CS_HIGH can't coexist well otherwise...
 537          */
 538         status = spi_setup(spi);
 539         if (status < 0) {
 540                 dev_err(dev, "can't setup %s, status %d\n",
 541                                 dev_name(&spi->dev), status);
 542                 goto done;
 543         }
 544
 545         /* Device may be bound to an active driver when this returns */
 546         status = device_add(&spi->dev);
 547         if (status < 0)
 548                 dev_err(dev, "can't add %s, status %d\n",
 549                                 dev_name(&spi->dev), status);
 550         else
 551                 dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
 552
 553 done:
 554         mutex_unlock(&spi_add_lock);
 555         return status;
 556 }
 557 EXPORT_SYMBOL_GPL(spi_add_device);
 558
 559 /**
 560  * spi_new_device - instantiate one new SPI device
 561  * @master: Controller to which device is connected
 562  * @chip: Describes the SPI device
 563  * Context: can sleep
 564  *
 565  * On typical mainboards, this is purely internal; and it's not needed
 566  * after board init creates the hard-wired devices.  Some development
 567  * platforms may not be able to use spi_register_board_info though, and
 568  * this is exported so that for example a USB or parport based adapter
 569  * driver could add devices (which it would learn about out-of-band).
 570  *
 571  * Return: the new device, or NULL.
 572  */
 573 struct spi_device *spi_new_device(struct spi_master *master,
 574                                   struct spi_board_info *chip)
 575 {
 576         struct spi_device       *proxy;
 577         int                     status;
 578
 579         /* NOTE:  caller did any chip->bus_num checks necessary.
 580          *
 581          * Also, unless we change the return value convention to use
 582          * error-or-pointer (not NULL-or-pointer), troubleshootability
 583          * suggests syslogged diagnostics are best here (ugh).
 584          */
 585
 586         proxy = spi_alloc_device(master);
 587         if (!proxy)
 588                 return NULL;
 589
 590         WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
 591
 592         proxy->chip_select = chip->chip_select;
 593         proxy->max_speed_hz = chip->max_speed_hz;
 594         proxy->mode = chip->mode;
 595         proxy->irq = chip->irq;
 596         strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
 597         proxy->dev.platform_data = (void *) chip->platform_data;
 598         proxy->controller_data = chip->controller_data;
 599         proxy->controller_state = NULL;
 600
 601         status = spi_add_device(proxy);
 602         if (status < 0) {
 603                 spi_dev_put(proxy);
 604                 return NULL;
 605         }
 606
 607         return proxy;
 608 }
 609 EXPORT_SYMBOL_GPL(spi_new_device);
 610
 611 /**
 612  * spi_unregister_device - unregister a single SPI device
 613  * @spi: spi_device to unregister
 614  *
 615  * Start making the passed SPI device vanish. Normally this would be handled
 616  * by spi_unregister_master().
 617  */
 618 void spi_unregister_device(struct spi_device *spi)
 619 {
 620         if (!spi)
 621                 return;
 622
 623         if (spi->dev.of_node)
 624                 of_node_clear_flag(spi->dev.of_node, OF_POPULATED);
 625         device_unregister(&spi->dev);
 626 }
 627 EXPORT_SYMBOL_GPL(spi_unregister_device);
 628
 629 static void spi_match_master_to_boardinfo(struct spi_master *master,
 630                                 struct spi_board_info *bi)
 631 {
 632         struct spi_device *dev;
 633
 634         if (master->bus_num != bi->bus_num)
 635                 return;
 636
 637         dev = spi_new_device(master, bi);
 638         if (!dev)
 639                 dev_err(master->dev.parent, "can't create new device for %s\n",
 640                         bi->modalias);
 641 }
 642
 643 /**
 644  * spi_register_board_info - register SPI devices for a given board
 645  * @info: array of chip descriptors
 646  * @n: how many descriptors are provided
 647  * Context: can sleep
 648  *
 649  * Board-specific early init code calls this (probably during arch_initcall)
 650  * with segments of the SPI device table.  Any device nodes are created later,
 651  * after the relevant parent SPI controller (bus_num) is defined.  We keep
 652  * this table of devices forever, so that reloading a controller driver will
 653  * not make Linux forget about these hard-wired devices.
 654  *
 655  * Other code can also call this, e.g. a particular add-on board might provide
 656  * SPI devices through its expansion connector, so code initializing that board
 657  * would naturally declare its SPI devices.
 658  *
 659  * The board info passed can safely be __initdata ... but be careful of
 660  * any embedded pointers (platform_data, etc), they're copied as-is.
 661  *
 662  * Return: zero on success, else a negative error code.
 663  */
 664 int spi_register_board_info(struct spi_board_info const *info, unsigned n)
 665 {
 666         struct boardinfo *bi;
 667         int i;
 668
 669         if (!n)
 670                 return -EINVAL;
 671
 672         bi = kzalloc(n * sizeof(*bi), GFP_KERNEL);
 673         if (!bi)
 674                 return -ENOMEM;
 675
 676         for (i = 0; i < n; i++, bi++, info++) {
 677                 struct spi_master *master;
 678
 679                 memcpy(&bi->board_info, info, sizeof(*info));
 680                 mutex_lock(&board_lock);
 681                 list_add_tail(&bi->list, &board_list);
 682                 list_for_each_entry(master, &spi_master_list, list)
 683                         spi_match_master_to_boardinfo(master, &bi->board_info);
 684                 mutex_unlock(&board_lock);
 685         }
 686
 687         return 0;
 688 }
 689
 690 /*-------------------------------------------------------------------------*/
 691
 692 static void spi_set_cs(struct spi_device *spi, bool enable)
 693 {
 694         if (spi->mode & SPI_CS_HIGH)
 695                 enable = !enable;
 696
 697         if (gpio_is_valid(spi->cs_gpio))
 698                 gpio_set_value(spi->cs_gpio, !enable);
 699         else if (spi->master->set_cs)
 700                 spi->master->set_cs(spi, !enable);
 701 }
 702
 703 #ifdef CONFIG_HAS_DMA
 704 static int spi_map_buf(struct spi_master *master, struct device *dev,
 705                        struct sg_table *sgt, void *buf, size_t len,
 706                        enum dma_data_direction dir)
 707 {
 708         const bool vmalloced_buf = is_vmalloc_addr(buf);
 709         unsigned int max_seg_size = dma_get_max_seg_size(dev);
 710         int desc_len;
 711         int sgs;
 712         struct page *vm_page;
 713         void *sg_buf;
 714         size_t min;
 715         int i, ret;
 716
 717         if (vmalloced_buf) {
 718                 desc_len = min_t(int, max_seg_size, PAGE_SIZE);
 719                 sgs = DIV_ROUND_UP(len + offset_in_page(buf), desc_len);
 720         } else {
 721                 desc_len = min_t(int, max_seg_size, master->max_dma_len);
 722                 sgs = DIV_ROUND_UP(len, desc_len);
 723         }
 724
 725         ret = sg_alloc_table(sgt, sgs, GFP_KERNEL);
 726         if (ret != 0)
 727                 return ret;
 728
 729         for (i = 0; i < sgs; i++) {
 730
 731                 if (vmalloced_buf) {
 732                         min = min_t(size_t,
 733                                     len, desc_len - offset_in_page(buf));
 734                         vm_page = vmalloc_to_page(buf);
 735                         if (!vm_page) {
 736                                 sg_free_table(sgt);
 737                                 return -ENOMEM;
 738                         }
 739                         sg_set_page(&sgt->sgl[i], vm_page,
 740                                     min, offset_in_page(buf));
 741                 } else {
 742                         min = min_t(size_t, len, desc_len);
 743                         sg_buf = buf;
 744                         sg_set_buf(&sgt->sgl[i], sg_buf, min);
 745                 }
 746
 747                 buf += min;
 748                 len -= min;
 749         }
 750
 751         ret = dma_map_sg(dev, sgt->sgl, sgt->nents, dir);
 752         if (!ret)
 753                 ret = -ENOMEM;
 754         if (ret < 0) {
 755                 sg_free_table(sgt);
 756                 return ret;
 757         }
 758
 759         sgt->nents = ret;
 760
 761         return 0;
 762 }
 763
 764 static void spi_unmap_buf(struct spi_master *master, struct device *dev,
 765                           struct sg_table *sgt, enum dma_data_direction dir)
 766 {
 767         if (sgt->orig_nents) {
 768                 dma_unmap_sg(dev, sgt->sgl, sgt->orig_nents, dir);
 769                 sg_free_table(sgt);
 770         }
 771 }
 772
 773 static int __spi_map_msg(struct spi_master *master, struct spi_message *msg)
 774 {
 775         struct device *tx_dev, *rx_dev;
 776         struct spi_transfer *xfer;
 777         int ret;
 778
 779         if (!master->can_dma)
 780                 return 0;
 781
 782         if (master->dma_tx)
 783                 tx_dev = master->dma_tx->device->dev;
 784         else
 785                 tx_dev = &master->dev;
 786
 787         if (master->dma_rx)
 788                 rx_dev = master->dma_rx->device->dev;
 789         else
 790                 rx_dev = &master->dev;
 791
 792         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 793                 if (!master->can_dma(master, msg->spi, xfer))
 794                         continue;
 795
 796                 if (xfer->tx_buf != NULL) {
 797                         ret = spi_map_buf(master, tx_dev, &xfer->tx_sg,
 798                                           (void *)xfer->tx_buf, xfer->len,
 799                                           DMA_TO_DEVICE);
 800                         if (ret != 0)
 801                                 return ret;
 802                 }
 803
 804                 if (xfer->rx_buf != NULL) {
 805                         ret = spi_map_buf(master, rx_dev, &xfer->rx_sg,
 806                                           xfer->rx_buf, xfer->len,
 807                                           DMA_FROM_DEVICE);
 808                         if (ret != 0) {
 809                                 spi_unmap_buf(master, tx_dev, &xfer->tx_sg,
 810                                               DMA_TO_DEVICE);
 811                                 return ret;
 812                         }
 813                 }
 814         }
 815
 816         master->cur_msg_mapped = true;
 817
 818         return 0;
 819 }
 820
 821 static int __spi_unmap_msg(struct spi_master *master, struct spi_message *msg)
 822 {
 823         struct spi_transfer *xfer;
 824         struct device *tx_dev, *rx_dev;
 825
 826         if (!master->cur_msg_mapped || !master->can_dma)
 827                 return 0;
 828
 829         if (master->dma_tx)
 830                 tx_dev = master->dma_tx->device->dev;
 831         else
 832                 tx_dev = &master->dev;
 833
 834         if (master->dma_rx)
 835                 rx_dev = master->dma_rx->device->dev;
 836         else
 837                 rx_dev = &master->dev;
 838
 839         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 840                 if (!master->can_dma(master, msg->spi, xfer))
 841                         continue;
 842
 843                 spi_unmap_buf(master, rx_dev, &xfer->rx_sg, DMA_FROM_DEVICE);
 844                 spi_unmap_buf(master, tx_dev, &xfer->tx_sg, DMA_TO_DEVICE);
 845         }
 846
 847         return 0;
 848 }
 849 #else /* !CONFIG_HAS_DMA */
 850 static inline int __spi_map_msg(struct spi_master *master,
 851                                 struct spi_message *msg)
 852 {
 853         return 0;
 854 }
 855
 856 static inline int __spi_unmap_msg(struct spi_master *master,
 857                                   struct spi_message *msg)
 858 {
 859         return 0;
 860 }
 861 #endif /* !CONFIG_HAS_DMA */
 862
 863 static inline int spi_unmap_msg(struct spi_master *master,
 864                                 struct spi_message *msg)
 865 {
 866         struct spi_transfer *xfer;
 867
 868         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 869                 /*
 870                  * Restore the original value of tx_buf or rx_buf if they are
 871                  * NULL.
 872                  */
 873                 if (xfer->tx_buf == master->dummy_tx)
 874                         xfer->tx_buf = NULL;
 875                 if (xfer->rx_buf == master->dummy_rx)
 876                         xfer->rx_buf = NULL;
 877         }
 878
 879         return __spi_unmap_msg(master, msg);
 880 }
 881
 882 static int spi_map_msg(struct spi_master *master, struct spi_message *msg)
 883 {
 884         struct spi_transfer *xfer;
 885         void *tmp;
 886         unsigned int max_tx, max_rx;
 887
 888         if (master->flags & (SPI_MASTER_MUST_RX | SPI_MASTER_MUST_TX)) {
 889                 max_tx = 0;
 890                 max_rx = 0;
 891
 892                 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 893                         if ((master->flags & SPI_MASTER_MUST_TX) &&
 894                             !xfer->tx_buf)
 895                                 max_tx = max(xfer->len, max_tx);
 896                         if ((master->flags & SPI_MASTER_MUST_RX) &&
 897                             !xfer->rx_buf)
 898                                 max_rx = max(xfer->len, max_rx);
 899                 }
 900
 901                 if (max_tx) {
 902                         tmp = krealloc(master->dummy_tx, max_tx,
 903                                        GFP_KERNEL | GFP_DMA);
 904                         if (!tmp)
 905                                 return -ENOMEM;
 906                         master->dummy_tx = tmp;
 907                         memset(tmp, 0, max_tx);
 908                 }
 909
 910                 if (max_rx) {
 911                         tmp = krealloc(master->dummy_rx, max_rx,
 912                                        GFP_KERNEL | GFP_DMA);
 913                         if (!tmp)
 914                                 return -ENOMEM;
 915                         master->dummy_rx = tmp;
 916                 }
 917
 918                 if (max_tx || max_rx) {
 919                         list_for_each_entry(xfer, &msg->transfers,
 920                                             transfer_list) {
 921                                 if (!xfer->tx_buf)
 922                                         xfer->tx_buf = master->dummy_tx;
 923                                 if (!xfer->rx_buf)
 924                                         xfer->rx_buf = master->dummy_rx;
 925                         }
 926                 }
 927         }
 928
 929         return __spi_map_msg(master, msg);
 930 }
 931
 932 /*
 933  * spi_transfer_one_message - Default implementation of transfer_one_message()
 934  *
 935  * This is a standard implementation of transfer_one_message() for
 936  * drivers which impelment a transfer_one() operation.  It provides
 937  * standard handling of delays and chip select management.
 938  */
 939 static int spi_transfer_one_message(struct spi_master *master,
 940                                     struct spi_message *msg)
 941 {
 942         struct spi_transfer *xfer;
 943         bool keep_cs = false;
 944         int ret = 0;
 945         unsigned long ms = 1;
 946         struct spi_statistics *statm = &master->statistics;
 947         struct spi_statistics *stats = &msg->spi->statistics;
 948
 949         spi_set_cs(msg->spi, true);
 950
 951         SPI_STATISTICS_INCREMENT_FIELD(statm, messages);
 952         SPI_STATISTICS_INCREMENT_FIELD(stats, messages);
 953
 954         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 955                 trace_spi_transfer_start(msg, xfer);
 956
 957                 spi_statistics_add_transfer_stats(statm, xfer, master);
 958                 spi_statistics_add_transfer_stats(stats, xfer, master);
 959
 960                 if (xfer->tx_buf || xfer->rx_buf) {
 961                         reinit_completion(&master->xfer_completion);
 962
 963                         ret = master->transfer_one(master, msg->spi, xfer);
 964                         if (ret < 0) {
 965                                 SPI_STATISTICS_INCREMENT_FIELD(statm,
 966                                                                errors);
 967                                 SPI_STATISTICS_INCREMENT_FIELD(stats,
 968                                                                errors);
 969                                 dev_err(&msg->spi->dev,
 970                                         "SPI transfer failed: %d\n", ret);
 971                                 goto out;
 972                         }
 973
 974                         if (ret > 0) {
 975                                 ret = 0;
 976                                 ms = xfer->len * 8 * 1000 / xfer->speed_hz;
 977                                 ms += ms + 100; /* some tolerance */
 978
 979                                 ms = wait_for_completion_timeout(&master->xfer_completion,
 980                                                                  msecs_to_jiffies(ms));
 981                         }
 982
 983                         if (ms == 0) {
 984                                 SPI_STATISTICS_INCREMENT_FIELD(statm,
 985                                                                timedout);
 986                                 SPI_STATISTICS_INCREMENT_FIELD(stats,
 987                                                                timedout);
 988                                 dev_err(&msg->spi->dev,
 989                                         "SPI transfer timed out\n");
 990                                 msg->status = -ETIMEDOUT;
 991                         }
 992                 } else {
 993                         if (xfer->len)
 994                                 dev_err(&msg->spi->dev,
 995                                         "Bufferless transfer has length %u\n",
 996                                         xfer->len);
 997                 }
 998
 999                 trace_spi_transfer_stop(msg, xfer);
1000
1001                 if (msg->status != -EINPROGRESS)
1002                         goto out;
1003
1004                 if (xfer->delay_usecs)
1005                         udelay(xfer->delay_usecs);
1006
1007                 if (xfer->cs_change) {
1008                         if (list_is_last(&xfer->transfer_list,
1009                                          &msg->transfers)) {
1010                                 keep_cs = true;
1011                         } else {
1012                                 spi_set_cs(msg->spi, false);
1013                                 udelay(10);
1014                                 spi_set_cs(msg->spi, true);
1015                         }
1016                 }
1017
1018                 msg->actual_length += xfer->len;
1019         }
1020
1021 out:
1022         if (ret != 0 || !keep_cs)
1023                 spi_set_cs(msg->spi, false);
1024
1025         if (msg->status == -EINPROGRESS)
1026                 msg->status = ret;
1027
1028         if (msg->status && master->handle_err)
1029                 master->handle_err(master, msg);
1030
1031         spi_res_release(master, msg);
1032
1033         spi_finalize_current_message(master);
1034
1035         return ret;
1036 }
1037
1038 /**
1039  * spi_finalize_current_transfer - report completion of a transfer
1040  * @master: the master reporting completion
1041  *
1042  * Called by SPI drivers using the core transfer_one_message()
1043  * implementation to notify it that the current interrupt driven
1044  * transfer has finished and the next one may be scheduled.
1045  */
1046 void spi_finalize_current_transfer(struct spi_master *master)
1047 {
1048         complete(&master->xfer_completion);
1049 }
1050 EXPORT_SYMBOL_GPL(spi_finalize_current_transfer);
1051
1052 /**
1053  * __spi_pump_messages - function which processes spi message queue
1054  * @master: master to process queue for
1055  * @in_kthread: true if we are in the context of the message pump thread
1056  * @bus_locked: true if the bus mutex is held when calling this function
1057  *
1058  * This function checks if there is any spi message in the queue that
1059  * needs processing and if so call out to the driver to initialize hardware
1060  * and transfer each message.
1061  *
1062  * Note that it is called both from the kthread itself and also from
1063  * inside spi_sync(); the queue extraction handling at the top of the
1064  * function should deal with this safely.
1065  */
1066 static void __spi_pump_messages(struct spi_master *master, bool in_kthread,
1067                                 bool bus_locked)
1068 {
1069         unsigned long flags;
1070         bool was_busy = false;
1071         int ret;
1072
1073         /* Lock queue */
1074         spin_lock_irqsave(&master->queue_lock, flags);
1075
1076         /* Make sure we are not already running a message */
1077         if (master->cur_msg) {
1078                 spin_unlock_irqrestore(&master->queue_lock, flags);
1079                 return;
1080         }
1081
1082         /* If another context is idling the device then defer */
1083         if (master->idling) {
1084                 queue_kthread_work(&master->kworker, &master->pump_messages);
1085                 spin_unlock_irqrestore(&master->queue_lock, flags);
1086                 return;
1087         }
1088
1089         /* Check if the queue is idle */
1090         if (list_empty(&master->queue) || !master->running) {
1091                 if (!master->busy) {
1092                         spin_unlock_irqrestore(&master->queue_lock, flags);
1093                         return;
1094                 }
1095
1096                 /* Only do teardown in the thread */
1097                 if (!in_kthread) {
1098                         queue_kthread_work(&master->kworker,
1099                                            &master->pump_messages);
1100                         spin_unlock_irqrestore(&master->queue_lock, flags);
1101                         return;
1102                 }
1103
1104                 master->busy = false;
1105                 master->idling = true;
1106                 spin_unlock_irqrestore(&master->queue_lock, flags);
1107
1108                 kfree(master->dummy_rx);
1109                 master->dummy_rx = NULL;
1110                 kfree(master->dummy_tx);
1111                 master->dummy_tx = NULL;
1112                 if (master->unprepare_transfer_hardware &&
1113                     master->unprepare_transfer_hardware(master))
1114                         dev_err(&master->dev,
1115                                 "failed to unprepare transfer hardware\n");
1116                 if (master->auto_runtime_pm) {
1117                         pm_runtime_mark_last_busy(master->dev.parent);
1118                         pm_runtime_put_autosuspend(master->dev.parent);
1119                 }
1120                 trace_spi_master_idle(master);
1121
1122                 spin_lock_irqsave(&master->queue_lock, flags);
1123                 master->idling = false;
1124                 spin_unlock_irqrestore(&master->queue_lock, flags);
1125                 return;
1126         }
1127
1128         /* Extract head of queue */
1129         master->cur_msg =
1130                 list_first_entry(&master->queue, struct spi_message, queue);
1131
1132         list_del_init(&master->cur_msg->queue);
1133         if (master->busy)
1134                 was_busy = true;
1135         else
1136                 master->busy = true;
1137         spin_unlock_irqrestore(&master->queue_lock, flags);
1138
1139         if (!was_busy && master->auto_runtime_pm) {
1140                 ret = pm_runtime_get_sync(master->dev.parent);
1141                 if (ret < 0) {
1142                         dev_err(&master->dev, "Failed to power device: %d\n",
1143                                 ret);
1144                         return;
1145                 }
1146         }
1147
1148         if (!was_busy)
1149                 trace_spi_master_busy(master);
1150
1151         if (!was_busy && master->prepare_transfer_hardware) {
1152                 ret = master->prepare_transfer_hardware(master);
1153                 if (ret) {
1154                         dev_err(&master->dev,
1155                                 "failed to prepare transfer hardware\n");
1156
1157                         if (master->auto_runtime_pm)
1158                                 pm_runtime_put(master->dev.parent);
1159                         return;
1160                 }
1161         }
1162
1163         if (!bus_locked)
1164                 mutex_lock(&master->bus_lock_mutex);
1165
1166         trace_spi_message_start(master->cur_msg);
1167
1168         if (master->prepare_message) {
1169                 ret = master->prepare_message(master, master->cur_msg);
1170                 if (ret) {
1171                         dev_err(&master->dev,
1172                                 "failed to prepare message: %d\n", ret);
1173                         master->cur_msg->status = ret;
1174                         spi_finalize_current_message(master);
1175                         goto out;
1176                 }
1177                 master->cur_msg_prepared = true;
1178         }
1179
1180         ret = spi_map_msg(master, master->cur_msg);
1181         if (ret) {
1182                 master->cur_msg->status = ret;
1183                 spi_finalize_current_message(master);
1184                 goto out;
1185         }
1186
1187         ret = master->transfer_one_message(master, master->cur_msg);
1188         if (ret) {
1189                 dev_err(&master->dev,
1190                         "failed to transfer one message from queue\n");
1191                 goto out;
1192         }
1193
1194 out:
1195         if (!bus_locked)
1196                 mutex_unlock(&master->bus_lock_mutex);
1197
1198         /* Prod the scheduler in case transfer_one() was busy waiting */
1199         if (!ret)
1200                 cond_resched();
1201 }
1202
1203 /**
1204  * spi_pump_messages - kthread work function which processes spi message queue
1205  * @work: pointer to kthread work struct contained in the master struct
1206  */
1207 static void spi_pump_messages(struct kthread_work *work)
1208 {
1209         struct spi_master *master =
1210                 container_of(work, struct spi_master, pump_messages);
1211
1212         __spi_pump_messages(master, true, false);
1213 }
1214
1215 static int spi_init_queue(struct spi_master *master)
1216 {
1217         struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 };
1218
1219         master->running = false;
1220         master->busy = false;
1221
1222         init_kthread_worker(&master->kworker);
1223         master->kworker_task = kthread_run(kthread_worker_fn,
1224                                            &master->kworker, "%s",
1225                                            dev_name(&master->dev));
1226         if (IS_ERR(master->kworker_task)) {
1227                 dev_err(&master->dev, "failed to create message pump task\n");
1228                 return PTR_ERR(master->kworker_task);
1229         }
1230         init_kthread_work(&master->pump_messages, spi_pump_messages);
1231
1232         /*
1233          * Master config will indicate if this controller should run the
1234          * message pump with high (realtime) priority to reduce the transfer
1235          * latency on the bus by minimising the delay between a transfer
1236          * request and the scheduling of the message pump thread. Without this
1237          * setting the message pump thread will remain at default priority.
1238          */
1239         if (master->rt) {
1240                 dev_info(&master->dev,
1241                         "will run message pump with realtime priority\n");
1242                 sched_setscheduler(master->kworker_task, SCHED_FIFO, &param);
1243         }
1244
1245         return 0;
1246 }
1247
1248 /**
1249  * spi_get_next_queued_message() - called by driver to check for queued
1250  * messages
1251  * @master: the master to check for queued messages
1252  *
1253  * If there are more messages in the queue, the next message is returned from
1254  * this call.
1255  *
1256  * Return: the next message in the queue, else NULL if the queue is empty.
1257  */
1258 struct spi_message *spi_get_next_queued_message(struct spi_master *master)
1259 {
1260         struct spi_message *next;
1261         unsigned long flags;
1262
1263         /* get a pointer to the next message, if any */
1264         spin_lock_irqsave(&master->queue_lock, flags);
1265         next = list_first_entry_or_null(&master->queue, struct spi_message,
1266                                         queue);
1267         spin_unlock_irqrestore(&master->queue_lock, flags);
1268
1269         return next;
1270 }
1271 EXPORT_SYMBOL_GPL(spi_get_next_queued_message);
1272
1273 /**
1274  * spi_finalize_current_message() - the current message is complete
1275  * @master: the master to return the message to
1276  *
1277  * Called by the driver to notify the core that the message in the front of the
1278  * queue is complete and can be removed from the queue.
1279  */
1280 void spi_finalize_current_message(struct spi_master *master)
1281 {
1282         struct spi_message *mesg;
1283         unsigned long flags;
1284         int ret;
1285
1286         spin_lock_irqsave(&master->queue_lock, flags);
1287         mesg = master->cur_msg;
1288         spin_unlock_irqrestore(&master->queue_lock, flags);
1289
1290         spi_unmap_msg(master, mesg);
1291
1292         if (master->cur_msg_prepared && master->unprepare_message) {
1293                 ret = master->unprepare_message(master, mesg);
1294                 if (ret) {
1295                         dev_err(&master->dev,
1296                                 "failed to unprepare message: %d\n", ret);
1297                 }
1298         }
1299
1300         spin_lock_irqsave(&master->queue_lock, flags);
1301         master->cur_msg = NULL;
1302         master->cur_msg_prepared = false;
1303         queue_kthread_work(&master->kworker, &master->pump_messages);
1304         spin_unlock_irqrestore(&master->queue_lock, flags);
1305
1306         trace_spi_message_done(mesg);
1307
1308         mesg->state = NULL;
1309         if (mesg->complete)
1310                 mesg->complete(mesg->context);
1311 }
1312 EXPORT_SYMBOL_GPL(spi_finalize_current_message);
1313
1314 static int spi_start_queue(struct spi_master *master)
1315 {
1316         unsigned long flags;
1317
1318         spin_lock_irqsave(&master->queue_lock, flags);
1319
1320         if (master->running || master->busy) {
1321                 spin_unlock_irqrestore(&master->queue_lock, flags);
1322                 return -EBUSY;
1323         }
1324
1325         master->running = true;
1326         master->cur_msg = NULL;
1327         spin_unlock_irqrestore(&master->queue_lock, flags);
1328
1329         queue_kthread_work(&master->kworker, &master->pump_messages);
1330
1331         return 0;
1332 }
1333
1334 static int spi_stop_queue(struct spi_master *master)
1335 {
1336         unsigned long flags;
1337         unsigned limit = 500;
1338         int ret = 0;
1339
1340         spin_lock_irqsave(&master->queue_lock, flags);
1341
1342         /*
1343          * This is a bit lame, but is optimized for the common execution path.
1344          * A wait_queue on the master->busy could be used, but then the common
1345          * execution path (pump_messages) would be required to call wake_up or
1346          * friends on every SPI message. Do this instead.
1347          */
1348         while ((!list_empty(&master->queue) || master->busy) && limit--) {
1349                 spin_unlock_irqrestore(&master->queue_lock, flags);
1350                 usleep_range(10000, 11000);
1351                 spin_lock_irqsave(&master->queue_lock, flags);
1352         }
1353
1354         if (!list_empty(&master->queue) || master->busy)
1355                 ret = -EBUSY;
1356         else
1357                 master->running = false;
1358
1359         spin_unlock_irqrestore(&master->queue_lock, flags);
1360
1361         if (ret) {
1362                 dev_warn(&master->dev,
1363                          "could not stop message queue\n");
1364                 return ret;
1365         }
1366         return ret;
1367 }
1368
1369 static int spi_destroy_queue(struct spi_master *master)
1370 {
1371         int ret;
1372
1373         ret = spi_stop_queue(master);
1374
1375         /*
1376          * flush_kthread_worker will block until all work is done.
1377          * If the reason that stop_queue timed out is that the work will never
1378          * finish, then it does no good to call flush/stop thread, so
1379          * return anyway.
1380          */
1381         if (ret) {
1382                 dev_err(&master->dev, "problem destroying queue\n");
1383                 return ret;
1384         }
1385
1386         flush_kthread_worker(&master->kworker);
1387         kthread_stop(master->kworker_task);
1388
1389         return 0;
1390 }
1391
1392 static int __spi_queued_transfer(struct spi_device *spi,
1393                                  struct spi_message *msg,
1394                                  bool need_pump)
1395 {
1396         struct spi_master *master = spi->master;
1397         unsigned long flags;
1398
1399         spin_lock_irqsave(&master->queue_lock, flags);
1400
1401         if (!master->running) {
1402                 spin_unlock_irqrestore(&master->queue_lock, flags);
1403                 return -ESHUTDOWN;
1404         }
1405         msg->actual_length = 0;
1406         msg->status = -EINPROGRESS;
1407
1408         list_add_tail(&msg->queue, &master->queue);
1409         if (!master->busy && need_pump)
1410                 queue_kthread_work(&master->kworker, &master->pump_messages);
1411
1412         spin_unlock_irqrestore(&master->queue_lock, flags);
1413         return 0;
1414 }
1415
1416 /**
1417  * spi_queued_transfer - transfer function for queued transfers
1418  * @spi: spi device which is requesting transfer
1419  * @msg: spi message which is to handled is queued to driver queue
1420  *
1421  * Return: zero on success, else a negative error code.
1422  */
1423 static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
1424 {
1425         return __spi_queued_transfer(spi, msg, true);
1426 }
1427
1428 static int spi_master_initialize_queue(struct spi_master *master)
1429 {
1430         int ret;
1431
1432         master->transfer = spi_queued_transfer;
1433         if (!master->transfer_one_message)
1434                 master->transfer_one_message = spi_transfer_one_message;
1435
1436         /* Initialize and start queue */
1437         ret = spi_init_queue(master);
1438         if (ret) {
1439                 dev_err(&master->dev, "problem initializing queue\n");
1440                 goto err_init_queue;
1441         }
1442         master->queued = true;
1443         ret = spi_start_queue(master);
1444         if (ret) {
1445                 dev_err(&master->dev, "problem starting queue\n");
1446                 goto err_start_queue;
1447         }
1448
1449         return 0;
1450
1451 err_start_queue:
1452         spi_destroy_queue(master);
1453 err_init_queue:
1454         return ret;
1455 }
1456
1457 /*-------------------------------------------------------------------------*/
1458
1459 #if defined(CONFIG_OF)
1460 static struct spi_device *
1461 of_register_spi_device(struct spi_master *master, struct device_node *nc)
1462 {
1463         struct spi_device *spi;
1464         int rc;
1465         u32 value;
1466
1467         /* Alloc an spi_device */
1468         spi = spi_alloc_device(master);
1469         if (!spi) {
1470                 dev_err(&master->dev, "spi_device alloc error for %s\n",
1471                         nc->full_name);
1472                 rc = -ENOMEM;
1473                 goto err_out;
1474         }
1475
1476         /* Select device driver */
1477         rc = of_modalias_node(nc, spi->modalias,
1478                                 sizeof(spi->modalias));
1479         if (rc < 0) {
1480                 dev_err(&master->dev, "cannot find modalias for %s\n",
1481                         nc->full_name);
1482                 goto err_out;
1483         }
1484
1485         /* Device address */
1486         rc = of_property_read_u32(nc, "reg", &value);
1487         if (rc) {
1488                 dev_err(&master->dev, "%s has no valid 'reg' property (%d)\n",
1489                         nc->full_name, rc);
1490                 goto err_out;
1491         }
1492         spi->chip_select = value;
1493
1494         /* Mode (clock phase/polarity/etc.) */
1495         if (of_find_property(nc, "spi-cpha", NULL))
1496                 spi->mode |= SPI_CPHA;
1497         if (of_find_property(nc, "spi-cpol", NULL))
1498                 spi->mode |= SPI_CPOL;
1499         if (of_find_property(nc, "spi-cs-high", NULL))
1500                 spi->mode |= SPI_CS_HIGH;
1501         if (of_find_property(nc, "spi-3wire", NULL))
1502                 spi->mode |= SPI_3WIRE;
1503         if (of_find_property(nc, "spi-lsb-first", NULL))
1504                 spi->mode |= SPI_LSB_FIRST;
1505
1506         /* Device DUAL/QUAD mode */
1507         if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) {
1508                 switch (value) {
1509                 case 1:
1510                         break;
1511                 case 2:
1512                         spi->mode |= SPI_TX_DUAL;
1513                         break;
1514                 case 4:
1515                         spi->mode |= SPI_TX_QUAD;
1516                         break;
1517                 default:
1518                         dev_warn(&master->dev,
1519                                 "spi-tx-bus-width %d not supported\n",
1520                                 value);
1521                         break;
1522                 }
1523         }
1524
1525         if (!of_property_read_u32(nc, "spi-rx-bus-width", &value)) {
1526                 switch (value) {
1527                 case 1:
1528                         break;
1529                 case 2:
1530                         spi->mode |= SPI_RX_DUAL;
1531                         break;
1532                 case 4:
1533                         spi->mode |= SPI_RX_QUAD;
1534                         break;
1535                 default:
1536                         dev_warn(&master->dev,
1537                                 "spi-rx-bus-width %d not supported\n",
1538                                 value);
1539                         break;
1540                 }
1541         }
1542
1543         /* Device speed */
1544         rc = of_property_read_u32(nc, "spi-max-frequency", &value);
1545         if (rc) {
1546                 dev_err(&master->dev, "%s has no valid 'spi-max-frequency' property (%d)\n",
1547                         nc->full_name, rc);
1548                 goto err_out;
1549         }
1550         spi->max_speed_hz = value;
1551
1552         /* Store a pointer to the node in the device structure */
1553         of_node_get(nc);
1554         spi->dev.of_node = nc;
1555
1556         /* Register the new device */
1557         rc = spi_add_device(spi);
1558         if (rc) {
1559                 dev_err(&master->dev, "spi_device register error %s\n",
1560                         nc->full_name);
1561                 goto err_out;
1562         }
1563
1564         return spi;
1565
1566 err_out:
1567         spi_dev_put(spi);
1568         return ERR_PTR(rc);
1569 }
1570
1571 /**
1572  * of_register_spi_devices() - Register child devices onto the SPI bus
1573  * @master:     Pointer to spi_master device
1574  *
1575  * Registers an spi_device for each child node of master node which has a 'reg'
1576  * property.
1577  */
1578 static void of_register_spi_devices(struct spi_master *master)
1579 {
1580         struct spi_device *spi;
1581         struct device_node *nc;
1582
1583         if (!master->dev.of_node)
1584                 return;
1585
1586         for_each_available_child_of_node(master->dev.of_node, nc) {
1587                 if (of_node_test_and_set_flag(nc, OF_POPULATED))
1588                         continue;
1589                 spi = of_register_spi_device(master, nc);
1590                 if (IS_ERR(spi))
1591                         dev_warn(&master->dev, "Failed to create SPI device for %s\n",
1592                                 nc->full_name);
1593         }
1594 }
1595 #else
1596 static void of_register_spi_devices(struct spi_master *master) { }
1597 #endif
1598
1599 #ifdef CONFIG_ACPI
1600 static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
1601 {
1602         struct spi_device *spi = data;
1603         struct spi_master *master = spi->master;
1604
1605         if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
1606                 struct acpi_resource_spi_serialbus *sb;
1607
1608                 sb = &ares->data.spi_serial_bus;
1609                 if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) {
1610                         /*
1611                          * ACPI DeviceSelection numbering is handled by the
1612                          * host controller driver in Windows and can vary
1613                          * from driver to driver. In Linux we always expect
1614                          * 0 .. max - 1 so we need to ask the driver to
1615                          * translate between the two schemes.
1616                          */
1617                         if (master->fw_translate_cs) {
1618                                 int cs = master->fw_translate_cs(master,
1619                                                 sb->device_selection);
1620                                 if (cs < 0)
1621                                         return cs;
1622                                 spi->chip_select = cs;
1623                         } else {
1624                                 spi->chip_select = sb->device_selection;
1625                         }
1626
1627                         spi->max_speed_hz = sb->connection_speed;
1628
1629                         if (sb->clock_phase == ACPI_SPI_SECOND_PHASE)
1630                                 spi->mode |= SPI_CPHA;
1631                         if (sb->clock_polarity == ACPI_SPI_START_HIGH)
1632                                 spi->mode |= SPI_CPOL;
1633                         if (sb->device_polarity == ACPI_SPI_ACTIVE_HIGH)
1634                                 spi->mode |= SPI_CS_HIGH;
1635                 }
1636         } else if (spi->irq < 0) {
1637                 struct resource r;
1638
1639                 if (acpi_dev_resource_interrupt(ares, 0, &r))
1640                         spi->irq = r.start;
1641         }
1642
1643         /* Always tell the ACPI core to skip this resource */
1644         return 1;
1645 }
1646
1647 static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level,
1648                                        void *data, void **return_value)
1649 {
1650         struct spi_master *master = data;
1651         struct list_head resource_list;
1652         struct acpi_device *adev;
1653         struct spi_device *spi;
1654         int ret;
1655
1656         if (acpi_bus_get_device(handle, &adev))
1657                 return AE_OK;
1658         if (acpi_bus_get_status(adev) || !adev->status.present)
1659                 return AE_OK;
1660
1661         spi = spi_alloc_device(master);
1662         if (!spi) {
1663                 dev_err(&master->dev, "failed to allocate SPI device for %s\n",
1664                         dev_name(&adev->dev));
1665                 return AE_NO_MEMORY;
1666         }
1667
1668         ACPI_COMPANION_SET(&spi->dev, adev);
1669         spi->irq = -1;
1670
1671         INIT_LIST_HEAD(&resource_list);
1672         ret = acpi_dev_get_resources(adev, &resource_list,
1673                                      acpi_spi_add_resource, spi);
1674         acpi_dev_free_resource_list(&resource_list);
1675
1676         if (ret < 0 || !spi->max_speed_hz) {
1677                 spi_dev_put(spi);
1678                 return AE_OK;
1679         }
1680
1681         if (spi->irq < 0)
1682                 spi->irq = acpi_dev_gpio_irq_get(adev, 0);
1683
1684         adev->power.flags.ignore_parent = true;
1685         strlcpy(spi->modalias, acpi_device_hid(adev), sizeof(spi->modalias));
1686         if (spi_add_device(spi)) {
1687                 adev->power.flags.ignore_parent = false;
1688                 dev_err(&master->dev, "failed to add SPI device %s from ACPI\n",
1689                         dev_name(&adev->dev));
1690                 spi_dev_put(spi);
1691         }
1692
1693         return AE_OK;
1694 }
1695
1696 static void acpi_register_spi_devices(struct spi_master *master)
1697 {
1698         acpi_status status;
1699         acpi_handle handle;
1700
1701         handle = ACPI_HANDLE(master->dev.parent);
1702         if (!handle)
1703                 return;
1704
1705         status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
1706                                      acpi_spi_add_device, NULL,
1707                                      master, NULL);
1708         if (ACPI_FAILURE(status))
1709                 dev_warn(&master->dev, "failed to enumerate SPI slaves\n");
1710 }
1711 #else
1712 static inline void acpi_register_spi_devices(struct spi_master *master) {}
1713 #endif /* CONFIG_ACPI */
1714
1715 static void spi_master_release(struct device *dev)
1716 {
1717         struct spi_master *master;
1718
1719         master = container_of(dev, struct spi_master, dev);
1720         kfree(master);
1721 }
1722
1723 static struct class spi_master_class = {
1724         .name           = "spi_master",
1725         .owner          = THIS_MODULE,
1726         .dev_release    = spi_master_release,
1727         .dev_groups     = spi_master_groups,
1728 };
1729
1730
1731 /**
1732  * spi_alloc_master - allocate SPI master controller
1733  * @dev: the controller, possibly using the platform_bus
1734  * @size: how much zeroed driver-private data to allocate; the pointer to this
1735  *      memory is in the driver_data field of the returned device,
1736  *      accessible with spi_master_get_devdata().
1737  * Context: can sleep
1738  *
1739  * This call is used only by SPI master controller drivers, which are the
1740  * only ones directly touching chip registers.  It's how they allocate
1741  * an spi_master structure, prior to calling spi_register_master().
1742  *
1743  * This must be called from context that can sleep.
1744  *
1745  * The caller is responsible for assigning the bus number and initializing
1746  * the master's methods before calling spi_register_master(); and (after errors
1747  * adding the device) calling spi_master_put() to prevent a memory leak.
1748  *
1749  * Return: the SPI master structure on success, else NULL.
1750  */
1751 struct spi_master *spi_alloc_master(struct device *dev, unsigned size)
1752 {
1753         struct spi_master       *master;
1754
1755         if (!dev)
1756                 return NULL;
1757
1758         master = kzalloc(size + sizeof(*master), GFP_KERNEL);
1759         if (!master)
1760                 return NULL;
1761
1762         device_initialize(&master->dev);
1763         master->bus_num = -1;
1764         master->num_chipselect = 1;
1765         master->dev.class = &spi_master_class;
1766         master->dev.parent = dev;
1767         spi_master_set_devdata(master, &master[1]);
1768
1769         return master;
1770 }
1771 EXPORT_SYMBOL_GPL(spi_alloc_master);
1772
1773 #ifdef CONFIG_OF
1774 static int of_spi_register_master(struct spi_master *master)
1775 {
1776         int nb, i, *cs;
1777         struct device_node *np = master->dev.of_node;
1778
1779         if (!np)
1780                 return 0;
1781
1782         nb = of_gpio_named_count(np, "cs-gpios");
1783         master->num_chipselect = max_t(int, nb, master->num_chipselect);
1784
1785         /* Return error only for an incorrectly formed cs-gpios property */
1786         if (nb == 0 || nb == -ENOENT)
1787                 return 0;
1788         else if (nb < 0)
1789                 return nb;
1790
1791         cs = devm_kzalloc(&master->dev,
1792                           sizeof(int) * master->num_chipselect,
1793                           GFP_KERNEL);
1794         master->cs_gpios = cs;
1795
1796         if (!master->cs_gpios)
1797                 return -ENOMEM;
1798
1799         for (i = 0; i < master->num_chipselect; i++)
1800                 cs[i] = -ENOENT;
1801
1802         for (i = 0; i < nb; i++)
1803                 cs[i] = of_get_named_gpio(np, "cs-gpios", i);
1804
1805         return 0;
1806 }
1807 #else
1808 static int of_spi_register_master(struct spi_master *master)
1809 {
1810         return 0;
1811 }
1812 #endif
1813
1814 /**
1815  * spi_register_master - register SPI master controller
1816  * @master: initialized master, originally from spi_alloc_master()
1817  * Context: can sleep
1818  *
1819  * SPI master controllers connect to their drivers using some non-SPI bus,
1820  * such as the platform bus.  The final stage of probe() in that code
1821  * includes calling spi_register_master() to hook up to this SPI bus glue.
1822  *
1823  * SPI controllers use board specific (often SOC specific) bus numbers,
1824  * and board-specific addressing for SPI devices combines those numbers
1825  * with chip select numbers.  Since SPI does not directly support dynamic
1826  * device identification, boards need configuration tables telling which
1827  * chip is at which address.
1828  *
1829  * This must be called from context that can sleep.  It returns zero on
1830  * success, else a negative error code (dropping the master's refcount).
1831  * After a successful return, the caller is responsible for calling
1832  * spi_unregister_master().
1833  *
1834  * Return: zero on success, else a negative error code.
1835  */
1836 int spi_register_master(struct spi_master *master)
1837 {
1838         static atomic_t         dyn_bus_id = ATOMIC_INIT((1<<15) - 1);
1839         struct device           *dev = master->dev.parent;
1840         struct boardinfo        *bi;
1841         int                     status = -ENODEV;
1842         int                     dynamic = 0;
1843
1844         if (!dev)
1845                 return -ENODEV;
1846
1847         status = of_spi_register_master(master);
1848         if (status)
1849                 return status;
1850
1851         /* even if it's just one always-selected device, there must
1852          * be at least one chipselect
1853          */
1854         if (master->num_chipselect == 0)
1855                 return -EINVAL;
1856
1857         if ((master->bus_num < 0) && master->dev.of_node)
1858                 master->bus_num = of_alias_get_id(master->dev.of_node, "spi");
1859
1860         /* convention:  dynamically assigned bus IDs count down from the max */
1861         if (master->bus_num < 0) {
1862                 /* FIXME switch to an IDR based scheme, something like
1863                  * I2C now uses, so we can't run out of "dynamic" IDs
1864                  */
1865                 master->bus_num = atomic_dec_return(&dyn_bus_id);
1866                 dynamic = 1;
1867         }
1868
1869         INIT_LIST_HEAD(&master->queue);
1870         spin_lock_init(&master->queue_lock);
1871         spin_lock_init(&master->bus_lock_spinlock);
1872         mutex_init(&master->bus_lock_mutex);
1873         master->bus_lock_flag = 0;
1874         init_completion(&master->xfer_completion);
1875         if (!master->max_dma_len)
1876                 master->max_dma_len = INT_MAX;
1877
1878         /* register the device, then userspace will see it.
1879          * registration fails if the bus ID is in use.
1880          */
1881         dev_set_name(&master->dev, "spi%u", master->bus_num);
1882         status = device_add(&master->dev);
1883         if (status < 0)
1884                 goto done;
1885         dev_dbg(dev, "registered master %s%s\n", dev_name(&master->dev),
1886                         dynamic ? " (dynamic)" : "");
1887
1888         /* If we're using a queued driver, start the queue */
1889         if (master->transfer)
1890                 dev_info(dev, "master is unqueued, this is deprecated\n");
1891         else {
1892                 status = spi_master_initialize_queue(master);
1893                 if (status) {
1894                         device_del(&master->dev);
1895                         goto done;
1896                 }
1897         }
1898         /* add statistics */
1899         spin_lock_init(&master->statistics.lock);
1900
1901         mutex_lock(&board_lock);
1902         list_add_tail(&master->list, &spi_master_list);
1903         list_for_each_entry(bi, &board_list, list)
1904                 spi_match_master_to_boardinfo(master, &bi->board_info);
1905         mutex_unlock(&board_lock);
1906
1907         /* Register devices from the device tree and ACPI */
1908         of_register_spi_devices(master);
1909         acpi_register_spi_devices(master);
1910 done:
1911         return status;
1912 }
1913 EXPORT_SYMBOL_GPL(spi_register_master);
1914
1915 static void devm_spi_unregister(struct device *dev, void *res)
1916 {
1917         spi_unregister_master(*(struct spi_master **)res);
1918 }
1919
1920 /**
1921  * dev_spi_register_master - register managed SPI master controller
1922  * @dev:    device managing SPI master
1923  * @master: initialized master, originally from spi_alloc_master()
1924  * Context: can sleep
1925  *
1926  * Register a SPI device as with spi_register_master() which will
1927  * automatically be unregister
1928  *
1929  * Return: zero on success, else a negative error code.
1930  */
1931 int devm_spi_register_master(struct device *dev, struct spi_master *master)
1932 {
1933         struct spi_master **ptr;
1934         int ret;
1935
1936         ptr = devres_alloc(devm_spi_unregister, sizeof(*ptr), GFP_KERNEL);
1937         if (!ptr)
1938                 return -ENOMEM;
1939
1940         ret = spi_register_master(master);
1941         if (!ret) {
1942                 *ptr = master;
1943                 devres_add(dev, ptr);
1944         } else {
1945                 devres_free(ptr);
1946         }
1947
1948         return ret;
1949 }
1950 EXPORT_SYMBOL_GPL(devm_spi_register_master);
1951
1952 static int __unregister(struct device *dev, void *null)
1953 {
1954         spi_unregister_device(to_spi_device(dev));
1955         return 0;
1956 }
1957
1958 /**
1959  * spi_unregister_master - unregister SPI master controller
1960  * @master: the master being unregistered
1961  * Context: can sleep
1962  *
1963  * This call is used only by SPI master controller drivers, which are the
1964  * only ones directly touching chip registers.
1965  *
1966  * This must be called from context that can sleep.
1967  */
1968 void spi_unregister_master(struct spi_master *master)
1969 {
1970         int dummy;
1971
1972         if (master->queued) {
1973                 if (spi_destroy_queue(master))
1974                         dev_err(&master->dev, "queue remove failed\n");
1975         }
1976
1977         mutex_lock(&board_lock);
1978         list_del(&master->list);
1979         mutex_unlock(&board_lock);
1980
1981         dummy = device_for_each_child(&master->dev, NULL, __unregister);
1982         device_unregister(&master->dev);
1983 }
1984 EXPORT_SYMBOL_GPL(spi_unregister_master);
1985
1986 int spi_master_suspend(struct spi_master *master)
1987 {
1988         int ret;
1989
1990         /* Basically no-ops for non-queued masters */
1991         if (!master->queued)
1992                 return 0;
1993
1994         ret = spi_stop_queue(master);
1995         if (ret)
1996                 dev_err(&master->dev, "queue stop failed\n");
1997
1998         return ret;
1999 }
2000 EXPORT_SYMBOL_GPL(spi_master_suspend);
2001
2002 int spi_master_resume(struct spi_master *master)
2003 {
2004         int ret;
2005
2006         if (!master->queued)
2007                 return 0;
2008
2009         ret = spi_start_queue(master);
2010         if (ret)
2011                 dev_err(&master->dev, "queue restart failed\n");
2012
2013         return ret;
2014 }
2015 EXPORT_SYMBOL_GPL(spi_master_resume);
2016
2017 static int __spi_master_match(struct device *dev, const void *data)
2018 {
2019         struct spi_master *m;
2020         const u16 *bus_num = data;
2021
2022         m = container_of(dev, struct spi_master, dev);
2023         return m->bus_num == *bus_num;
2024 }
2025
2026 /**
2027  * spi_busnum_to_master - look up master associated with bus_num
2028  * @bus_num: the master's bus number
2029  * Context: can sleep
2030  *
2031  * This call may be used with devices that are registered after
2032  * arch init time.  It returns a refcounted pointer to the relevant
2033  * spi_master (which the caller must release), or NULL if there is
2034  * no such master registered.
2035  *
2036  * Return: the SPI master structure on success, else NULL.
2037  */
2038 struct spi_master *spi_busnum_to_master(u16 bus_num)
2039 {
2040         struct device           *dev;
2041         struct spi_master       *master = NULL;
2042
2043         dev = class_find_device(&spi_master_class, NULL, &bus_num,
2044                                 __spi_master_match);
2045         if (dev)
2046                 master = container_of(dev, struct spi_master, dev);
2047         /* reference got in class_find_device */
2048         return master;
2049 }
2050 EXPORT_SYMBOL_GPL(spi_busnum_to_master);
2051
2052 /*-------------------------------------------------------------------------*/
2053
2054 /* Core methods for SPI resource management */
2055
2056 /**
2057  * spi_res_alloc - allocate a spi resource that is life-cycle managed
2058  *                 during the processing of a spi_message while using
2059  *                 spi_transfer_one
2060  * @spi:     the spi device for which we allocate memory
2061  * @release: the release code to execute for this resource
2062  * @size:    size to alloc and return
2063  * @gfp:     GFP allocation flags
2064  *
2065  * Return: the pointer to the allocated data
2066  *
2067  * This may get enhanced in the future to allocate from a memory pool
2068  * of the @spi_device or @spi_master to avoid repeated allocations.
2069  */
2070 void *spi_res_alloc(struct spi_device *spi,
2071                     spi_res_release_t release,
2072                     size_t size, gfp_t gfp)
2073 {
2074         struct spi_res *sres;
2075
2076         sres = kzalloc(sizeof(*sres) + size, gfp);
2077         if (!sres)
2078                 return NULL;
2079
2080         INIT_LIST_HEAD(&sres->entry);
2081         sres->release = release;
2082
2083         return sres->data;
2084 }
2085 EXPORT_SYMBOL_GPL(spi_res_alloc);
2086
2087 /**
2088  * spi_res_free - free an spi resource
2089  * @res: pointer to the custom data of a resource
2090  *
2091  */
2092 void spi_res_free(void *res)
2093 {
2094         struct spi_res *sres = container_of(res, struct spi_res, data);
2095
2096         if (!res)
2097                 return;
2098
2099         WARN_ON(!list_empty(&sres->entry));
2100         kfree(sres);
2101 }
2102 EXPORT_SYMBOL_GPL(spi_res_free);
2103
2104 /**
2105  * spi_res_add - add a spi_res to the spi_message
2106  * @message: the spi message
2107  * @res:     the spi_resource
2108  */
2109 void spi_res_add(struct spi_message *message, void *res)
2110 {
2111         struct spi_res *sres = container_of(res, struct spi_res, data);
2112
2113         WARN_ON(!list_empty(&sres->entry));
2114         list_add_tail(&sres->entry, &message->resources);
2115 }
2116 EXPORT_SYMBOL_GPL(spi_res_add);
2117
2118 /**
2119  * spi_res_release - release all spi resources for this message
2120  * @master:  the @spi_master
2121  * @message: the @spi_message
2122  */
2123 void spi_res_release(struct spi_master *master,
2124                      struct spi_message *message)
2125 {
2126         struct spi_res *res;
2127
2128         while (!list_empty(&message->resources)) {
2129                 res = list_last_entry(&message->resources,
2130                                       struct spi_res, entry);
2131
2132                 if (res->release)
2133                         res->release(master, message, res->data);
2134
2135                 list_del(&res->entry);
2136
2137                 kfree(res);
2138         }
2139 }
2140 EXPORT_SYMBOL_GPL(spi_res_release);
2141
2142 /*-------------------------------------------------------------------------*/
2143
2144 /* Core methods for spi_message alterations */
2145
2146 static void __spi_replace_transfers_release(struct spi_master *master,
2147                                             struct spi_message *msg,
2148                                             void *res)
2149 {
2150         struct spi_replaced_transfers *rxfer = res;
2151         size_t i;
2152
2153         /* call extra callback if requested */
2154         if (rxfer->release)
2155                 rxfer->release(master, msg, res);
2156
2157         /* insert replaced transfers back into the message */
2158         list_splice(&rxfer->replaced_transfers, rxfer->replaced_after);
2159
2160         /* remove the formerly inserted entries */
2161         for (i = 0; i < rxfer->inserted; i++)
2162                 list_del(&rxfer->inserted_transfers[i].transfer_list);
2163 }
2164
2165 /**
2166  * spi_replace_transfers - replace transfers with several transfers
2167  *                         and register change with spi_message.resources
2168  * @msg:           the spi_message we work upon
2169  * @xfer_first:    the first spi_transfer we want to replace
2170  * @remove:        number of transfers to remove
2171  * @insert:        the number of transfers we want to insert instead
2172  * @release:       extra release code necessary in some circumstances
2173  * @extradatasize: extra data to allocate (with alignment guarantees
2174  *                 of struct @spi_transfer)
2175  * @gfp:           gfp flags
2176  *
2177  * Returns: pointer to @spi_replaced_transfers,
2178  *          PTR_ERR(...) in case of errors.
2179  */
2180 struct spi_replaced_transfers *spi_replace_transfers(
2181         struct spi_message *msg,
2182         struct spi_transfer *xfer_first,
2183         size_t remove,
2184         size_t insert,
2185         spi_replaced_release_t release,
2186         size_t extradatasize,
2187         gfp_t gfp)
2188 {
2189         struct spi_replaced_transfers *rxfer;
2190         struct spi_transfer *xfer;
2191         size_t i;
2192
2193         /* allocate the structure using spi_res */
2194         rxfer = spi_res_alloc(msg->spi, __spi_replace_transfers_release,
2195                               insert * sizeof(struct spi_transfer)
2196                               + sizeof(struct spi_replaced_transfers)
2197                               + extradatasize,
2198                               gfp);
2199         if (!rxfer)
2200                 return ERR_PTR(-ENOMEM);
2201
2202         /* the release code to invoke before running the generic release */
2203         rxfer->release = release;
2204
2205         /* assign extradata */
2206         if (extradatasize)
2207                 rxfer->extradata =
2208                         &rxfer->inserted_transfers[insert];
2209
2210         /* init the replaced_transfers list */
2211         INIT_LIST_HEAD(&rxfer->replaced_transfers);
2212
2213         /* assign the list_entry after which we should reinsert
2214          * the @replaced_transfers - it may be spi_message.messages!
2215          */
2216         rxfer->replaced_after = xfer_first->transfer_list.prev;
2217
2218         /* remove the requested number of transfers */
2219         for (i = 0; i < remove; i++) {
2220                 /* if the entry after replaced_after it is msg->transfers
2221                  * then we have been requested to remove more transfers
2222                  * than are in the list
2223                  */
2224                 if (rxfer->replaced_after->next == &msg->transfers) {
2225                         dev_err(&msg->spi->dev,
2226                                 "requested to remove more spi_transfers than are available\n");
2227                         /* insert replaced transfers back into the message */
2228                         list_splice(&rxfer->replaced_transfers,
2229                                     rxfer->replaced_after);
2230
2231                         /* free the spi_replace_transfer structure */
2232                         spi_res_free(rxfer);
2233
2234                         /* and return with an error */
2235                         return ERR_PTR(-EINVAL);
2236                 }
2237
2238                 /* remove the entry after replaced_after from list of
2239                  * transfers and add it to list of replaced_transfers
2240                  */
2241                 list_move_tail(rxfer->replaced_after->next,
2242                                &rxfer->replaced_transfers);
2243         }
2244
2245         /* create copy of the given xfer with identical settings
2246          * based on the first transfer to get removed
2247          */
2248         for (i = 0; i < insert; i++) {
2249                 /* we need to run in reverse order */
2250                 xfer = &rxfer->inserted_transfers[insert - 1 - i];
2251
2252                 /* copy all spi_transfer data */
2253                 memcpy(xfer, xfer_first, sizeof(*xfer));
2254
2255                 /* add to list */
2256                 list_add(&xfer->transfer_list, rxfer->replaced_after);
2257
2258                 /* clear cs_change and delay_usecs for all but the last */
2259                 if (i) {
2260                         xfer->cs_change = false;
2261                         xfer->delay_usecs = 0;
2262                 }
2263         }
2264
2265         /* set up inserted */
2266         rxfer->inserted = insert;
2267
2268         /* and register it with spi_res/spi_message */
2269         spi_res_add(msg, rxfer);
2270
2271         return rxfer;
2272 }
2273 EXPORT_SYMBOL_GPL(spi_replace_transfers);
2274
2275 static int __spi_split_transfer_maxsize(struct spi_master *master,
2276                                         struct spi_message *msg,
2277                                         struct spi_transfer **xferp,
2278                                         size_t maxsize,
2279                                         gfp_t gfp)
2280 {
2281         struct spi_transfer *xfer = *xferp, *xfers;
2282         struct spi_replaced_transfers *srt;
2283         size_t offset;
2284         size_t count, i;
2285
2286         /* warn once about this fact that we are splitting a transfer */
2287         dev_warn_once(&msg->spi->dev,
2288                       "spi_transfer of length %i exceed max length of %zu - needed to split transfers\n",
2289                       xfer->len, maxsize);
2290
2291         /* calculate how many we have to replace */
2292         count = DIV_ROUND_UP(xfer->len, maxsize);
2293
2294         /* create replacement */
2295         srt = spi_replace_transfers(msg, xfer, 1, count, NULL, 0, gfp);
2296         if (IS_ERR(srt))
2297                 return PTR_ERR(srt);
2298         xfers = srt->inserted_transfers;
2299
2300         /* now handle each of those newly inserted spi_transfers
2301          * note that the replacements spi_transfers all are preset
2302          * to the same values as *xferp, so tx_buf, rx_buf and len
2303          * are all identical (as well as most others)
2304          * so we just have to fix up len and the pointers.
2305          *
2306          * this also includes support for the depreciated
2307          * spi_message.is_dma_mapped interface
2308          */
2309
2310         /* the first transfer just needs the length modified, so we
2311          * run it outside the loop
2312          */
2313         xfers[0].len = min_t(size_t, maxsize, xfer[0].len);
2314
2315         /* all the others need rx_buf/tx_buf also set */
2316         for (i = 1, offset = maxsize; i < count; offset += maxsize, i++) {
2317                 /* update rx_buf, tx_buf and dma */
2318                 if (xfers[i].rx_buf)
2319                         xfers[i].rx_buf += offset;
2320                 if (xfers[i].rx_dma)
2321                         xfers[i].rx_dma += offset;
2322                 if (xfers[i].tx_buf)
2323                         xfers[i].tx_buf += offset;
2324                 if (xfers[i].tx_dma)
2325                         xfers[i].tx_dma += offset;
2326
2327                 /* update length */
2328                 xfers[i].len = min(maxsize, xfers[i].len - offset);
2329         }
2330
2331         /* we set up xferp to the last entry we have inserted,
2332          * so that we skip those already split transfers
2333          */
2334         *xferp = &xfers[count - 1];
2335
2336         /* increment statistics counters */
2337         SPI_STATISTICS_INCREMENT_FIELD(&master->statistics,
2338                                        transfers_split_maxsize);
2339         SPI_STATISTICS_INCREMENT_FIELD(&msg->spi->statistics,
2340                                        transfers_split_maxsize);
2341
2342         return 0;
2343 }
2344
2345 /**
2346  * spi_split_tranfers_maxsize - split spi transfers into multiple transfers
2347  *                              when an individual transfer exceeds a
2348  *                              certain size
2349  * @master:    the @spi_master for this transfer
2350  * @msg:   the @spi_message to transform
2351  * @maxsize:  the maximum when to apply this
2352  * @gfp: GFP allocation flags
2353  *
2354  * Return: status of transformation
2355  */
2356 int spi_split_transfers_maxsize(struct spi_master *master,
2357                                 struct spi_message *msg,
2358                                 size_t maxsize,
2359                                 gfp_t gfp)
2360 {
2361         struct spi_transfer *xfer;
2362         int ret;
2363
2364         /* iterate over the transfer_list,
2365          * but note that xfer is advanced to the last transfer inserted
2366          * to avoid checking sizes again unnecessarily (also xfer does
2367          * potentiall belong to a different list by the time the
2368          * replacement has happened
2369          */
2370         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
2371                 if (xfer->len > maxsize) {
2372                         ret = __spi_split_transfer_maxsize(
2373                                 master, msg, &xfer, maxsize, gfp);
2374                         if (ret)
2375                                 return ret;
2376                 }
2377         }
2378
2379         return 0;
2380 }
2381 EXPORT_SYMBOL_GPL(spi_split_transfers_maxsize);
2382
2383 /*-------------------------------------------------------------------------*/
2384
2385 /* Core methods for SPI master protocol drivers.  Some of the
2386  * other core methods are currently defined as inline functions.
2387  */
2388
2389 static int __spi_validate_bits_per_word(struct spi_master *master, u8 bits_per_word)
2390 {
2391         if (master->bits_per_word_mask) {
2392                 /* Only 32 bits fit in the mask */
2393                 if (bits_per_word > 32)
2394                         return -EINVAL;
2395                 if (!(master->bits_per_word_mask &
2396                                 SPI_BPW_MASK(bits_per_word)))
2397                         return -EINVAL;
2398         }
2399
2400         return 0;
2401 }
2402
2403 /**
2404  * spi_setup - setup SPI mode and clock rate
2405  * @spi: the device whose settings are being modified
2406  * Context: can sleep, and no requests are queued to the device
2407  *
2408  * SPI protocol drivers may need to update the transfer mode if the
2409  * device doesn't work with its default.  They may likewise need
2410  * to update clock rates or word sizes from initial values.  This function
2411  * changes those settings, and must be called from a context that can sleep.
2412  * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
2413  * effect the next time the device is selected and data is transferred to
2414  * or from it.  When this function returns, the spi device is deselected.
2415  *
2416  * Note that this call will fail if the protocol driver specifies an option
2417  * that the underlying controller or its driver does not support.  For
2418  * example, not all hardware supports wire transfers using nine bit words,
2419  * LSB-first wire encoding, or active-high chipselects.
2420  *
2421  * Return: zero on success, else a negative error code.
2422  */
2423 int spi_setup(struct spi_device *spi)
2424 {
2425         unsigned        bad_bits, ugly_bits;
2426         int             status;
2427
2428         /* check mode to prevent that DUAL and QUAD set at the same time
2429          */
2430         if (((spi->mode & SPI_TX_DUAL) && (spi->mode & SPI_TX_QUAD)) ||
2431                 ((spi->mode & SPI_RX_DUAL) && (spi->mode & SPI_RX_QUAD))) {
2432                 dev_err(&spi->dev,
2433                 "setup: can not select dual and quad at the same time\n");
2434                 return -EINVAL;
2435         }
2436         /* if it is SPI_3WIRE mode, DUAL and QUAD should be forbidden
2437          */
2438         if ((spi->mode & SPI_3WIRE) && (spi->mode &
2439                 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD)))
2440                 return -EINVAL;
2441         /* help drivers fail *cleanly* when they need options
2442          * that aren't supported with their current master
2443          */
2444         bad_bits = spi->mode & ~spi->master->mode_bits;
2445         ugly_bits = bad_bits &
2446                     (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD);
2447         if (ugly_bits) {
2448                 dev_warn(&spi->dev,
2449                          "setup: ignoring unsupported mode bits %x\n",
2450                          ugly_bits);
2451                 spi->mode &= ~ugly_bits;
2452                 bad_bits &= ~ugly_bits;
2453         }
2454         if (bad_bits) {
2455                 dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
2456                         bad_bits);
2457                 return -EINVAL;
2458         }
2459
2460         if (!spi->bits_per_word)
2461                 spi->bits_per_word = 8;
2462
2463         status = __spi_validate_bits_per_word(spi->master, spi->bits_per_word);
2464         if (status)
2465                 return status;
2466
2467         if (!spi->max_speed_hz)
2468                 spi->max_speed_hz = spi->master->max_speed_hz;
2469
2470         if (spi->master->setup)
2471                 status = spi->master->setup(spi);
2472
2473         spi_set_cs(spi, false);
2474
2475         dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
2476                         (int) (spi->mode & (SPI_CPOL | SPI_CPHA)),
2477                         (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
2478                         (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
2479                         (spi->mode & SPI_3WIRE) ? "3wire, " : "",
2480                         (spi->mode & SPI_LOOP) ? "loopback, " : "",
2481                         spi->bits_per_word, spi->max_speed_hz,
2482                         status);
2483
2484         return status;
2485 }
2486 EXPORT_SYMBOL_GPL(spi_setup);
2487
2488 static int __spi_validate(struct spi_device *spi, struct spi_message *message)
2489 {
2490         struct spi_master *master = spi->master;
2491         struct spi_transfer *xfer;
2492         int w_size;
2493
2494         if (list_empty(&message->transfers))
2495                 return -EINVAL;
2496
2497         /* Half-duplex links include original MicroWire, and ones with
2498          * only one data pin like SPI_3WIRE (switches direction) or where
2499          * either MOSI or MISO is missing.  They can also be caused by
2500          * software limitations.
2501          */
2502         if ((master->flags & SPI_MASTER_HALF_DUPLEX)
2503                         || (spi->mode & SPI_3WIRE)) {
2504                 unsigned flags = master->flags;
2505
2506                 list_for_each_entry(xfer, &message->transfers, transfer_list) {
2507                         if (xfer->rx_buf && xfer->tx_buf)
2508                                 return -EINVAL;
2509                         if ((flags & SPI_MASTER_NO_TX) && xfer->tx_buf)
2510                                 return -EINVAL;
2511                         if ((flags & SPI_MASTER_NO_RX) && xfer->rx_buf)
2512                                 return -EINVAL;
2513                 }
2514         }
2515
2516         /**
2517          * Set transfer bits_per_word and max speed as spi device default if
2518          * it is not set for this transfer.
2519          * Set transfer tx_nbits and rx_nbits as single transfer default
2520          * (SPI_NBITS_SINGLE) if it is not set for this transfer.
2521          */
2522         message->frame_length = 0;
2523         list_for_each_entry(xfer, &message->transfers, transfer_list) {
2524                 message->frame_length += xfer->len;
2525                 if (!xfer->bits_per_word)
2526                         xfer->bits_per_word = spi->bits_per_word;
2527
2528                 if (!xfer->speed_hz)
2529                         xfer->speed_hz = spi->max_speed_hz;
2530                 if (!xfer->speed_hz)
2531                         xfer->speed_hz = master->max_speed_hz;
2532
2533                 if (master->max_speed_hz &&
2534                     xfer->speed_hz > master->max_speed_hz)
2535                         xfer->speed_hz = master->max_speed_hz;
2536
2537                 if (__spi_validate_bits_per_word(master, xfer->bits_per_word))
2538                         return -EINVAL;
2539
2540                 /*
2541                  * SPI transfer length should be multiple of SPI word size
2542                  * where SPI word size should be power-of-two multiple
2543                  */
2544                 if (xfer->bits_per_word <= 8)
2545                         w_size = 1;
2546                 else if (xfer->bits_per_word <= 16)
2547                         w_size = 2;
2548                 else
2549                         w_size = 4;
2550
2551                 /* No partial transfers accepted */
2552                 if (xfer->len % w_size)
2553                         return -EINVAL;
2554
2555                 if (xfer->speed_hz && master->min_speed_hz &&
2556                     xfer->speed_hz < master->min_speed_hz)
2557                         return -EINVAL;
2558
2559                 if (xfer->tx_buf && !xfer->tx_nbits)
2560                         xfer->tx_nbits = SPI_NBITS_SINGLE;
2561                 if (xfer->rx_buf && !xfer->rx_nbits)
2562                         xfer->rx_nbits = SPI_NBITS_SINGLE;
2563                 /* check transfer tx/rx_nbits:
2564                  * 1. check the value matches one of single, dual and quad
2565                  * 2. check tx/rx_nbits match the mode in spi_device
2566                  */
2567                 if (xfer->tx_buf) {
2568                         if (xfer->tx_nbits != SPI_NBITS_SINGLE &&
2569                                 xfer->tx_nbits != SPI_NBITS_DUAL &&
2570                                 xfer->tx_nbits != SPI_NBITS_QUAD)
2571                                 return -EINVAL;
2572                         if ((xfer->tx_nbits == SPI_NBITS_DUAL) &&
2573                                 !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
2574                                 return -EINVAL;
2575                         if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
2576                                 !(spi->mode & SPI_TX_QUAD))
2577                                 return -EINVAL;
2578                 }
2579                 /* check transfer rx_nbits */
2580                 if (xfer->rx_buf) {
2581                         if (xfer->rx_nbits != SPI_NBITS_SINGLE &&
2582                                 xfer->rx_nbits != SPI_NBITS_DUAL &&
2583                                 xfer->rx_nbits != SPI_NBITS_QUAD)
2584                                 return -EINVAL;
2585                         if ((xfer->rx_nbits == SPI_NBITS_DUAL) &&
2586                                 !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
2587                                 return -EINVAL;
2588                         if ((xfer->rx_nbits == SPI_NBITS_QUAD) &&
2589                                 !(spi->mode & SPI_RX_QUAD))
2590                                 return -EINVAL;
2591                 }
2592         }
2593
2594         message->status = -EINPROGRESS;
2595
2596         return 0;
2597 }
2598
2599 static int __spi_async(struct spi_device *spi, struct spi_message *message)
2600 {
2601         struct spi_master *master = spi->master;
2602
2603         message->spi = spi;
2604
2605         SPI_STATISTICS_INCREMENT_FIELD(&master->statistics, spi_async);
2606         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_async);
2607
2608         trace_spi_message_submit(message);
2609
2610         return master->transfer(spi, message);
2611 }
2612
2613 /**
2614  * spi_async - asynchronous SPI transfer
2615  * @spi: device with which data will be exchanged
2616  * @message: describes the data transfers, including completion callback
2617  * Context: any (irqs may be blocked, etc)
2618  *
2619  * This call may be used in_irq and other contexts which can't sleep,
2620  * as well as from task contexts which can sleep.
2621  *
2622  * The completion callback is invoked in a context which can't sleep.
2623  * Before that invocation, the value of message->status is undefined.
2624  * When the callback is issued, message->status holds either zero (to
2625  * indicate complete success) or a negative error code.  After that
2626  * callback returns, the driver which issued the transfer request may
2627  * deallocate the associated memory; it's no longer in use by any SPI
2628  * core or controller driver code.
2629  *
2630  * Note that although all messages to a spi_device are handled in
2631  * FIFO order, messages may go to different devices in other orders.
2632  * Some device might be higher priority, or have various "hard" access
2633  * time requirements, for example.
2634  *
2635  * On detection of any fault during the transfer, processing of
2636  * the entire message is aborted, and the device is deselected.
2637  * Until returning from the associated message completion callback,
2638  * no other spi_message queued to that device will be processed.
2639  * (This rule applies equally to all the synchronous transfer calls,
2640  * which are wrappers around this core asynchronous primitive.)
2641  *
2642  * Return: zero on success, else a negative error code.
2643  */
2644 int spi_async(struct spi_device *spi, struct spi_message *message)
2645 {
2646         struct spi_master *master = spi->master;
2647         int ret;
2648         unsigned long flags;
2649
2650         ret = __spi_validate(spi, message);
2651         if (ret != 0)
2652                 return ret;
2653
2654         spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2655
2656         if (master->bus_lock_flag)
2657                 ret = -EBUSY;
2658         else
2659                 ret = __spi_async(spi, message);
2660
2661         spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2662
2663         return ret;
2664 }
2665 EXPORT_SYMBOL_GPL(spi_async);
2666
2667 /**
2668  * spi_async_locked - version of spi_async with exclusive bus usage
2669  * @spi: device with which data will be exchanged
2670  * @message: describes the data transfers, including completion callback
2671  * Context: any (irqs may be blocked, etc)
2672  *
2673  * This call may be used in_irq and other contexts which can't sleep,
2674  * as well as from task contexts which can sleep.
2675  *
2676  * The completion callback is invoked in a context which can't sleep.
2677  * Before that invocation, the value of message->status is undefined.
2678  * When the callback is issued, message->status holds either zero (to
2679  * indicate complete success) or a negative error code.  After that
2680  * callback returns, the driver which issued the transfer request may
2681  * deallocate the associated memory; it's no longer in use by any SPI
2682  * core or controller driver code.
2683  *
2684  * Note that although all messages to a spi_device are handled in
2685  * FIFO order, messages may go to different devices in other orders.
2686  * Some device might be higher priority, or have various "hard" access
2687  * time requirements, for example.
2688  *
2689  * On detection of any fault during the transfer, processing of
2690  * the entire message is aborted, and the device is deselected.
2691  * Until returning from the associated message completion callback,
2692  * no other spi_message queued to that device will be processed.
2693  * (This rule applies equally to all the synchronous transfer calls,
2694  * which are wrappers around this core asynchronous primitive.)
2695  *
2696  * Return: zero on success, else a negative error code.
2697  */
2698 int spi_async_locked(struct spi_device *spi, struct spi_message *message)
2699 {
2700         struct spi_master *master = spi->master;
2701         int ret;
2702         unsigned long flags;
2703
2704         ret = __spi_validate(spi, message);
2705         if (ret != 0)
2706                 return ret;
2707
2708         spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2709
2710         ret = __spi_async(spi, message);
2711
2712         spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2713
2714         return ret;
2715
2716 }
2717 EXPORT_SYMBOL_GPL(spi_async_locked);
2718
2719
2720 int spi_flash_read(struct spi_device *spi,
2721                    struct spi_flash_read_message *msg)
2722
2723 {
2724         struct spi_master *master = spi->master;
2725         int ret;
2726
2727         if ((msg->opcode_nbits == SPI_NBITS_DUAL ||
2728              msg->addr_nbits == SPI_NBITS_DUAL) &&
2729             !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
2730                 return -EINVAL;
2731         if ((msg->opcode_nbits == SPI_NBITS_QUAD ||
2732              msg->addr_nbits == SPI_NBITS_QUAD) &&
2733             !(spi->mode & SPI_TX_QUAD))
2734                 return -EINVAL;
2735         if (msg->data_nbits == SPI_NBITS_DUAL &&
2736             !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
2737                 return -EINVAL;
2738         if (msg->data_nbits == SPI_NBITS_QUAD &&
2739             !(spi->mode &  SPI_RX_QUAD))
2740                 return -EINVAL;
2741
2742         if (master->auto_runtime_pm) {
2743                 ret = pm_runtime_get_sync(master->dev.parent);
2744                 if (ret < 0) {
2745                         dev_err(&master->dev, "Failed to power device: %d\n",
2746                                 ret);
2747                         return ret;
2748                 }
2749         }
2750         mutex_lock(&master->bus_lock_mutex);
2751         ret = master->spi_flash_read(spi, msg);
2752         mutex_unlock(&master->bus_lock_mutex);
2753         if (master->auto_runtime_pm)
2754                 pm_runtime_put(master->dev.parent);
2755
2756         return ret;
2757 }
2758 EXPORT_SYMBOL_GPL(spi_flash_read);
2759
2760 /*-------------------------------------------------------------------------*/
2761
2762 /* Utility methods for SPI master protocol drivers, layered on
2763  * top of the core.  Some other utility methods are defined as
2764  * inline functions.
2765  */
2766
2767 static void spi_complete(void *arg)
2768 {
2769         complete(arg);
2770 }
2771
2772 static int __spi_sync(struct spi_device *spi, struct spi_message *message,
2773                       int bus_locked)
2774 {
2775         DECLARE_COMPLETION_ONSTACK(done);
2776         int status;
2777         struct spi_master *master = spi->master;
2778         unsigned long flags;
2779
2780         status = __spi_validate(spi, message);
2781         if (status != 0)
2782                 return status;
2783
2784         message->complete = spi_complete;
2785         message->context = &done;
2786         message->spi = spi;
2787
2788         SPI_STATISTICS_INCREMENT_FIELD(&master->statistics, spi_sync);
2789         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_sync);
2790
2791         if (!bus_locked)
2792                 mutex_lock(&master->bus_lock_mutex);
2793
2794         /* If we're not using the legacy transfer method then we will
2795          * try to transfer in the calling context so special case.
2796          * This code would be less tricky if we could remove the
2797          * support for driver implemented message queues.
2798          */
2799         if (master->transfer == spi_queued_transfer) {
2800                 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2801
2802                 trace_spi_message_submit(message);
2803
2804                 status = __spi_queued_transfer(spi, message, false);
2805
2806                 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2807         } else {
2808                 status = spi_async_locked(spi, message);
2809         }
2810
2811         if (!bus_locked)
2812                 mutex_unlock(&master->bus_lock_mutex);
2813
2814         if (status == 0) {
2815                 /* Push out the messages in the calling context if we
2816                  * can.
2817                  */
2818                 if (master->transfer == spi_queued_transfer) {
2819                         SPI_STATISTICS_INCREMENT_FIELD(&master->statistics,
2820                                                        spi_sync_immediate);
2821                         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics,
2822                                                        spi_sync_immediate);
2823                         __spi_pump_messages(master, false, bus_locked);
2824                 }
2825
2826                 wait_for_completion(&done);
2827                 status = message->status;
2828         }
2829         message->context = NULL;
2830         return status;
2831 }
2832
2833 /**
2834  * spi_sync - blocking/synchronous SPI data transfers
2835  * @spi: device with which data will be exchanged
2836  * @message: describes the data transfers
2837  * Context: can sleep
2838  *
2839  * This call may only be used from a context that may sleep.  The sleep
2840  * is non-interruptible, and has no timeout.  Low-overhead controller
2841  * drivers may DMA directly into and out of the message buffers.
2842  *
2843  * Note that the SPI device's chip select is active during the message,
2844  * and then is normally disabled between messages.  Drivers for some
2845  * frequently-used devices may want to minimize costs of selecting a chip,
2846  * by leaving it selected in anticipation that the next message will go
2847  * to the same chip.  (That may increase power usage.)
2848  *
2849  * Also, the caller is guaranteeing that the memory associated with the
2850  * message will not be freed before this call returns.
2851  *
2852  * Return: zero on success, else a negative error code.
2853  */
2854 int spi_sync(struct spi_device *spi, struct spi_message *message)
2855 {
2856         return __spi_sync(spi, message, 0);
2857 }
2858 EXPORT_SYMBOL_GPL(spi_sync);
2859
2860 /**
2861  * spi_sync_locked - version of spi_sync with exclusive bus usage
2862  * @spi: device with which data will be exchanged
2863  * @message: describes the data transfers
2864  * Context: can sleep
2865  *
2866  * This call may only be used from a context that may sleep.  The sleep
2867  * is non-interruptible, and has no timeout.  Low-overhead controller
2868  * drivers may DMA directly into and out of the message buffers.
2869  *
2870  * This call should be used by drivers that require exclusive access to the
2871  * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
2872  * be released by a spi_bus_unlock call when the exclusive access is over.
2873  *
2874  * Return: zero on success, else a negative error code.
2875  */
2876 int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
2877 {
2878         return __spi_sync(spi, message, 1);
2879 }
2880 EXPORT_SYMBOL_GPL(spi_sync_locked);
2881
2882 /**
2883  * spi_bus_lock - obtain a lock for exclusive SPI bus usage
2884  * @master: SPI bus master that should be locked for exclusive bus access
2885  * Context: can sleep
2886  *
2887  * This call may only be used from a context that may sleep.  The sleep
2888  * is non-interruptible, and has no timeout.
2889  *
2890  * This call should be used by drivers that require exclusive access to the
2891  * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
2892  * exclusive access is over. Data transfer must be done by spi_sync_locked
2893  * and spi_async_locked calls when the SPI bus lock is held.
2894  *
2895  * Return: always zero.
2896  */
2897 int spi_bus_lock(struct spi_master *master)
2898 {
2899         unsigned long flags;
2900
2901         mutex_lock(&master->bus_lock_mutex);
2902
2903         spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2904         master->bus_lock_flag = 1;
2905         spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2906
2907         /* mutex remains locked until spi_bus_unlock is called */
2908
2909         return 0;
2910 }
2911 EXPORT_SYMBOL_GPL(spi_bus_lock);
2912
2913 /**
2914  * spi_bus_unlock - release the lock for exclusive SPI bus usage
2915  * @master: SPI bus master that was locked for exclusive bus access
2916  * Context: can sleep
2917  *
2918  * This call may only be used from a context that may sleep.  The sleep
2919  * is non-interruptible, and has no timeout.
2920  *
2921  * This call releases an SPI bus lock previously obtained by an spi_bus_lock
2922  * call.
2923  *
2924  * Return: always zero.
2925  */
2926 int spi_bus_unlock(struct spi_master *master)
2927 {
2928         master->bus_lock_flag = 0;
2929
2930         mutex_unlock(&master->bus_lock_mutex);
2931
2932         return 0;
2933 }
2934 EXPORT_SYMBOL_GPL(spi_bus_unlock);
2935
2936 /* portable code must never pass more than 32 bytes */
2937 #define SPI_BUFSIZ      max(32, SMP_CACHE_BYTES)
2938
2939 static u8       *buf;
2940
2941 /**
2942  * spi_write_then_read - SPI synchronous write followed by read
2943  * @spi: device with which data will be exchanged
2944  * @txbuf: data to be written (need not be dma-safe)
2945  * @n_tx: size of txbuf, in bytes
2946  * @rxbuf: buffer into which data will be read (need not be dma-safe)
2947  * @n_rx: size of rxbuf, in bytes
2948  * Context: can sleep
2949  *
2950  * This performs a half duplex MicroWire style transaction with the
2951  * device, sending txbuf and then reading rxbuf.  The return value
2952  * is zero for success, else a negative errno status code.
2953  * This call may only be used from a context that may sleep.
2954  *
2955  * Parameters to this routine are always copied using a small buffer;
2956  * portable code should never use this for more than 32 bytes.
2957  * Performance-sensitive or bulk transfer code should instead use
2958  * spi_{async,sync}() calls with dma-safe buffers.
2959  *
2960  * Return: zero on success, else a negative error code.
2961  */
2962 int spi_write_then_read(struct spi_device *spi,
2963                 const void *txbuf, unsigned n_tx,
2964                 void *rxbuf, unsigned n_rx)
2965 {
2966         static DEFINE_MUTEX(lock);
2967
2968         int                     status;
2969         struct spi_message      message;
2970         struct spi_transfer     x[2];
2971         u8                      *local_buf;
2972
2973         /* Use preallocated DMA-safe buffer if we can.  We can't avoid
2974          * copying here, (as a pure convenience thing), but we can
2975          * keep heap costs out of the hot path unless someone else is
2976          * using the pre-allocated buffer or the transfer is too large.
2977          */
2978         if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) {
2979                 local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx),
2980                                     GFP_KERNEL | GFP_DMA);
2981                 if (!local_buf)
2982                         return -ENOMEM;
2983         } else {
2984                 local_buf = buf;
2985         }
2986
2987         spi_message_init(&message);
2988         memset(x, 0, sizeof(x));
2989         if (n_tx) {
2990                 x[0].len = n_tx;
2991                 spi_message_add_tail(&x[0], &message);
2992         }
2993         if (n_rx) {
2994                 x[1].len = n_rx;
2995                 spi_message_add_tail(&x[1], &message);
2996         }
2997
2998         memcpy(local_buf, txbuf, n_tx);
2999         x[0].tx_buf = local_buf;
3000         x[1].rx_buf = local_buf + n_tx;
3001
3002         /* do the i/o */
3003         status = spi_sync(spi, &message);
3004         if (status == 0)
3005                 memcpy(rxbuf, x[1].rx_buf, n_rx);
3006
3007         if (x[0].tx_buf == buf)
3008                 mutex_unlock(&lock);
3009         else
3010                 kfree(local_buf);
3011
3012         return status;
3013 }
3014 EXPORT_SYMBOL_GPL(spi_write_then_read);
3015
3016 /*-------------------------------------------------------------------------*/
3017
3018 #if IS_ENABLED(CONFIG_OF_DYNAMIC)
3019 static int __spi_of_device_match(struct device *dev, void *data)
3020 {
3021         return dev->of_node == data;
3022 }
3023
3024 /* must call put_device() when done with returned spi_device device */
3025 static struct spi_device *of_find_spi_device_by_node(struct device_node *node)
3026 {
3027         struct device *dev = bus_find_device(&spi_bus_type, NULL, node,
3028                                                 __spi_of_device_match);
3029         return dev ? to_spi_device(dev) : NULL;
3030 }
3031
3032 static int __spi_of_master_match(struct device *dev, const void *data)
3033 {
3034         return dev->of_node == data;
3035 }
3036
3037 /* the spi masters are not using spi_bus, so we find it with another way */
3038 static struct spi_master *of_find_spi_master_by_node(struct device_node *node)
3039 {
3040         struct device *dev;
3041
3042         dev = class_find_device(&spi_master_class, NULL, node,
3043                                 __spi_of_master_match);
3044         if (!dev)
3045                 return NULL;
3046
3047         /* reference got in class_find_device */
3048         return container_of(dev, struct spi_master, dev);
3049 }
3050
3051 static int of_spi_notify(struct notifier_block *nb, unsigned long action,
3052                          void *arg)
3053 {
3054         struct of_reconfig_data *rd = arg;
3055         struct spi_master *master;
3056         struct spi_device *spi;
3057
3058         switch (of_reconfig_get_state_change(action, arg)) {
3059         case OF_RECONFIG_CHANGE_ADD:
3060                 master = of_find_spi_master_by_node(rd->dn->parent);
3061                 if (master == NULL)
3062                         return NOTIFY_OK;       /* not for us */
3063
3064                 if (of_node_test_and_set_flag(rd->dn, OF_POPULATED)) {
3065                         put_device(&master->dev);
3066                         return NOTIFY_OK;
3067                 }
3068
3069                 spi = of_register_spi_device(master, rd->dn);
3070                 put_device(&master->dev);
3071
3072                 if (IS_ERR(spi)) {
3073                         pr_err("%s: failed to create for '%s'\n",
3074                                         __func__, rd->dn->full_name);
3075                         return notifier_from_errno(PTR_ERR(spi));
3076                 }
3077                 break;
3078
3079         case OF_RECONFIG_CHANGE_REMOVE:
3080                 /* already depopulated? */
3081                 if (!of_node_check_flag(rd->dn, OF_POPULATED))
3082                         return NOTIFY_OK;
3083
3084                 /* find our device by node */
3085                 spi = of_find_spi_device_by_node(rd->dn);
3086                 if (spi == NULL)
3087                         return NOTIFY_OK;       /* no? not meant for us */
3088
3089                 /* unregister takes one ref away */
3090                 spi_unregister_device(spi);
3091
3092                 /* and put the reference of the find */
3093                 put_device(&spi->dev);
3094                 break;
3095         }
3096
3097         return NOTIFY_OK;
3098 }
3099
3100 static struct notifier_block spi_of_notifier = {
3101         .notifier_call = of_spi_notify,
3102 };
3103 #else /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
3104 extern struct notifier_block spi_of_notifier;
3105 #endif /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
3106
3107 static int __init spi_init(void)
3108 {
3109         int     status;
3110
3111         buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
3112         if (!buf) {
3113                 status = -ENOMEM;
3114                 goto err0;
3115         }
3116
3117         status = bus_register(&spi_bus_type);
3118         if (status < 0)
3119                 goto err1;
3120
3121         status = class_register(&spi_master_class);
3122         if (status < 0)
3123                 goto err2;
3124
3125         if (IS_ENABLED(CONFIG_OF_DYNAMIC))
3126                 WARN_ON(of_reconfig_notifier_register(&spi_of_notifier));
3127
3128         return 0;
3129
3130 err2:
3131         bus_unregister(&spi_bus_type);
3132 err1:
3133         kfree(buf);
3134         buf = NULL;
3135 err0:
3136         return status;
3137 }
3138
3139 /* board_info is normally registered in arch_initcall(),
3140  * but even essential drivers wait till later
3141  *
3142  * REVISIT only boardinfo really needs static linking. the rest (device and
3143  * driver registration) _could_ be dynamically linked (modular) ... costs
3144  * include needing to have boardinfo data structures be much more public.
3145  */
3146 postcore_initcall(spi_init);
3147