root/drivers/spi/spi-mem.c

DEFINITIONS

1. spi_controller_dma_map_mem_op_data
2. spi_controller_dma_unmap_mem_op_data
3. spi_check_buswidth_req
4. spi_mem_default_supports_op
5. spi_mem_buswidth_is_valid
6. spi_mem_check_op
7. spi_mem_internal_supports_op
8. spi_mem_supports_op
9. spi_mem_access_start
10. spi_mem_access_end
11. spi_mem_exec_op
12. spi_mem_get_name
13. spi_mem_adjust_op_size
14. spi_mem_no_dirmap_read
15. spi_mem_no_dirmap_write
16. spi_mem_dirmap_create
17. spi_mem_dirmap_destroy
18. devm_spi_mem_dirmap_release
19. devm_spi_mem_dirmap_create
20. devm_spi_mem_dirmap_match
21. devm_spi_mem_dirmap_destroy
22. spi_mem_dirmap_read
23. spi_mem_dirmap_write
24. to_spi_mem_drv
25. spi_mem_probe
26. spi_mem_remove
27. spi_mem_shutdown
28. spi_mem_driver_register_with_owner
29. spi_mem_driver_unregister

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * Copyright (C) 2018 Exceet Electronics GmbH
   4  * Copyright (C) 2018 Bootlin
   5  *
   6  * Author: Boris Brezillon <boris.brezillon@bootlin.com>
   7  */
   8 #include <linux/dmaengine.h>
   9 #include <linux/pm_runtime.h>
  10 #include <linux/spi/spi.h>
  11 #include <linux/spi/spi-mem.h>
  12 
  13 #include "internals.h"
  14 
  15 #define SPI_MEM_MAX_BUSWIDTH            8
  16 
  17 /**
  18  * spi_controller_dma_map_mem_op_data() - DMA-map the buffer attached to a
  19  *                                        memory operation
  20  * @ctlr: the SPI controller requesting this dma_map()
  21  * @op: the memory operation containing the buffer to map
  22  * @sgt: a pointer to a non-initialized sg_table that will be filled by this
  23  *       function
  24  *
  25  * Some controllers might want to do DMA on the data buffer embedded in @op.
  26  * This helper prepares everything for you and provides a ready-to-use
  27  * sg_table. This function is not intended to be called from spi drivers.
  28  * Only SPI controller drivers should use it.
  29  * Note that the caller must ensure the memory region pointed by
  30  * op->data.buf.{in,out} is DMA-able before calling this function.
  31  *
  32  * Return: 0 in case of success, a negative error code otherwise.
  33  */
  34 int spi_controller_dma_map_mem_op_data(struct spi_controller *ctlr,
  35                                        const struct spi_mem_op *op,
  36                                        struct sg_table *sgt)
  37 {
  38         struct device *dmadev;
  39 
  40         if (!op->data.nbytes)
  41                 return -EINVAL;
  42 
  43         if (op->data.dir == SPI_MEM_DATA_OUT && ctlr->dma_tx)
  44                 dmadev = ctlr->dma_tx->device->dev;
  45         else if (op->data.dir == SPI_MEM_DATA_IN && ctlr->dma_rx)
  46                 dmadev = ctlr->dma_rx->device->dev;
  47         else
  48                 dmadev = ctlr->dev.parent;
  49 
  50         if (!dmadev)
  51                 return -EINVAL;
  52 
  53         return spi_map_buf(ctlr, dmadev, sgt, op->data.buf.in, op->data.nbytes,
  54                            op->data.dir == SPI_MEM_DATA_IN ?
  55                            DMA_FROM_DEVICE : DMA_TO_DEVICE);
  56 }
  57 EXPORT_SYMBOL_GPL(spi_controller_dma_map_mem_op_data);
  58 
  59 /**
  60  * spi_controller_dma_unmap_mem_op_data() - DMA-unmap the buffer attached to a
  61  *                                          memory operation
  62  * @ctlr: the SPI controller requesting this dma_unmap()
  63  * @op: the memory operation containing the buffer to unmap
  64  * @sgt: a pointer to an sg_table previously initialized by
  65  *       spi_controller_dma_map_mem_op_data()
  66  *
  67  * Some controllers might want to do DMA on the data buffer embedded in @op.
  68  * This helper prepares things so that the CPU can access the
  69  * op->data.buf.{in,out} buffer again.
  70  *
  71  * This function is not intended to be called from SPI drivers. Only SPI
  72  * controller drivers should use it.
  73  *
  74  * This function should be called after the DMA operation has finished and is
  75  * only valid if the previous spi_controller_dma_map_mem_op_data() call
  76  * returned 0.
  77  *
  78  * Return: 0 in case of success, a negative error code otherwise.
  79  */
  80 void spi_controller_dma_unmap_mem_op_data(struct spi_controller *ctlr,
  81                                           const struct spi_mem_op *op,
  82                                           struct sg_table *sgt)
  83 {
  84         struct device *dmadev;
  85 
  86         if (!op->data.nbytes)
  87                 return;
  88 
  89         if (op->data.dir == SPI_MEM_DATA_OUT && ctlr->dma_tx)
  90                 dmadev = ctlr->dma_tx->device->dev;
  91         else if (op->data.dir == SPI_MEM_DATA_IN && ctlr->dma_rx)
  92                 dmadev = ctlr->dma_rx->device->dev;
  93         else
  94                 dmadev = ctlr->dev.parent;
  95 
  96         spi_unmap_buf(ctlr, dmadev, sgt,
  97                       op->data.dir == SPI_MEM_DATA_IN ?
  98                       DMA_FROM_DEVICE : DMA_TO_DEVICE);
  99 }
 100 EXPORT_SYMBOL_GPL(spi_controller_dma_unmap_mem_op_data);
 101 
 102 static int spi_check_buswidth_req(struct spi_mem *mem, u8 buswidth, bool tx)
 103 {
 104         u32 mode = mem->spi->mode;
 105 
 106         switch (buswidth) {
 107         case 1:
 108                 return 0;
 109 
 110         case 2:
 111                 if ((tx && (mode & (SPI_TX_DUAL | SPI_TX_QUAD))) ||
 112                     (!tx && (mode & (SPI_RX_DUAL | SPI_RX_QUAD))))
 113                         return 0;
 114 
 115                 break;
 116 
 117         case 4:
 118                 if ((tx && (mode & SPI_TX_QUAD)) ||
 119                     (!tx && (mode & SPI_RX_QUAD)))
 120                         return 0;
 121 
 122                 break;
 123 
 124         case 8:
 125                 if ((tx && (mode & SPI_TX_OCTAL)) ||
 126                     (!tx && (mode & SPI_RX_OCTAL)))
 127                         return 0;
 128 
 129                 break;
 130 
 131         default:
 132                 break;
 133         }
 134 
 135         return -ENOTSUPP;
 136 }
 137 
 138 bool spi_mem_default_supports_op(struct spi_mem *mem,
 139                                  const struct spi_mem_op *op)
 140 {
 141         if (spi_check_buswidth_req(mem, op->cmd.buswidth, true))
 142                 return false;
 143 
 144         if (op->addr.nbytes &&
 145             spi_check_buswidth_req(mem, op->addr.buswidth, true))
 146                 return false;
 147 
 148         if (op->dummy.nbytes &&
 149             spi_check_buswidth_req(mem, op->dummy.buswidth, true))
 150                 return false;
 151 
 152         if (op->data.dir != SPI_MEM_NO_DATA &&
 153             spi_check_buswidth_req(mem, op->data.buswidth,
 154                                    op->data.dir == SPI_MEM_DATA_OUT))
 155                 return false;
 156 
 157         return true;
 158 }
 159 EXPORT_SYMBOL_GPL(spi_mem_default_supports_op);
 160 
 161 static bool spi_mem_buswidth_is_valid(u8 buswidth)
 162 {
 163         if (hweight8(buswidth) > 1 || buswidth > SPI_MEM_MAX_BUSWIDTH)
 164                 return false;
 165 
 166         return true;
 167 }
 168 
 169 static int spi_mem_check_op(const struct spi_mem_op *op)
 170 {
 171         if (!op->cmd.buswidth)
 172                 return -EINVAL;
 173 
 174         if ((op->addr.nbytes && !op->addr.buswidth) ||
 175             (op->dummy.nbytes && !op->dummy.buswidth) ||
 176             (op->data.nbytes && !op->data.buswidth))
 177                 return -EINVAL;
 178 
 179         if (!spi_mem_buswidth_is_valid(op->cmd.buswidth) ||
 180             !spi_mem_buswidth_is_valid(op->addr.buswidth) ||
 181             !spi_mem_buswidth_is_valid(op->dummy.buswidth) ||
 182             !spi_mem_buswidth_is_valid(op->data.buswidth))
 183                 return -EINVAL;
 184 
 185         return 0;
 186 }
 187 
 188 static bool spi_mem_internal_supports_op(struct spi_mem *mem,
 189                                          const struct spi_mem_op *op)
 190 {
 191         struct spi_controller *ctlr = mem->spi->controller;
 192 
 193         if (ctlr->mem_ops && ctlr->mem_ops->supports_op)
 194                 return ctlr->mem_ops->supports_op(mem, op);
 195 
 196         return spi_mem_default_supports_op(mem, op);
 197 }
 198 
 199 /**
 200  * spi_mem_supports_op() - Check if a memory device and the controller it is
 201  *                         connected to support a specific memory operation
 202  * @mem: the SPI memory
 203  * @op: the memory operation to check
 204  *
 205  * Some controllers are only supporting Single or Dual IOs, others might only
 206  * support specific opcodes, or it can even be that the controller and device
 207  * both support Quad IOs but the hardware prevents you from using it because
 208  * only 2 IO lines are connected.
 209  *
 210  * This function checks whether a specific operation is supported.
 211  *
 212  * Return: true if @op is supported, false otherwise.
 213  */
 214 bool spi_mem_supports_op(struct spi_mem *mem, const struct spi_mem_op *op)
 215 {
 216         if (spi_mem_check_op(op))
 217                 return false;
 218 
 219         return spi_mem_internal_supports_op(mem, op);
 220 }
 221 EXPORT_SYMBOL_GPL(spi_mem_supports_op);
 222 
 223 static int spi_mem_access_start(struct spi_mem *mem)
 224 {
 225         struct spi_controller *ctlr = mem->spi->controller;
 226 
 227         /*
 228          * Flush the message queue before executing our SPI memory
 229          * operation to prevent preemption of regular SPI transfers.
 230          */
 231         spi_flush_queue(ctlr);
 232 
 233         if (ctlr->auto_runtime_pm) {
 234                 int ret;
 235 
 236                 ret = pm_runtime_get_sync(ctlr->dev.parent);
 237                 if (ret < 0) {
 238                         dev_err(&ctlr->dev, "Failed to power device: %d\n",
 239                                 ret);
 240                         return ret;
 241                 }
 242         }
 243 
 244         mutex_lock(&ctlr->bus_lock_mutex);
 245         mutex_lock(&ctlr->io_mutex);
 246 
 247         return 0;
 248 }
 249 
 250 static void spi_mem_access_end(struct spi_mem *mem)
 251 {
 252         struct spi_controller *ctlr = mem->spi->controller;
 253 
 254         mutex_unlock(&ctlr->io_mutex);
 255         mutex_unlock(&ctlr->bus_lock_mutex);
 256 
 257         if (ctlr->auto_runtime_pm)
 258                 pm_runtime_put(ctlr->dev.parent);
 259 }
 260 
 261 /**
 262  * spi_mem_exec_op() - Execute a memory operation
 263  * @mem: the SPI memory
 264  * @op: the memory operation to execute
 265  *
 266  * Executes a memory operation.
 267  *
 268  * This function first checks that @op is supported and then tries to execute
 269  * it.
 270  *
 271  * Return: 0 in case of success, a negative error code otherwise.
 272  */
 273 int spi_mem_exec_op(struct spi_mem *mem, const struct spi_mem_op *op)
 274 {
 275         unsigned int tmpbufsize, xferpos = 0, totalxferlen = 0;
 276         struct spi_controller *ctlr = mem->spi->controller;
 277         struct spi_transfer xfers[4] = { };
 278         struct spi_message msg;
 279         u8 *tmpbuf;
 280         int ret;
 281 
 282         ret = spi_mem_check_op(op);
 283         if (ret)
 284                 return ret;
 285 
 286         if (!spi_mem_internal_supports_op(mem, op))
 287                 return -ENOTSUPP;
 288 
 289         if (ctlr->mem_ops) {
 290                 ret = spi_mem_access_start(mem);
 291                 if (ret)
 292                         return ret;
 293 
 294                 ret = ctlr->mem_ops->exec_op(mem, op);
 295 
 296                 spi_mem_access_end(mem);
 297 
 298                 /*
 299                  * Some controllers only optimize specific paths (typically the
 300                  * read path) and expect the core to use the regular SPI
 301                  * interface in other cases.
 302                  */
 303                 if (!ret || ret != -ENOTSUPP)
 304                         return ret;
 305         }
 306 
 307         tmpbufsize = sizeof(op->cmd.opcode) + op->addr.nbytes +
 308                      op->dummy.nbytes;
 309 
 310         /*
 311          * Allocate a buffer to transmit the CMD, ADDR cycles with kmalloc() so
 312          * we're guaranteed that this buffer is DMA-able, as required by the
 313          * SPI layer.
 314          */
 315         tmpbuf = kzalloc(tmpbufsize, GFP_KERNEL | GFP_DMA);
 316         if (!tmpbuf)
 317                 return -ENOMEM;
 318 
 319         spi_message_init(&msg);
 320 
 321         tmpbuf[0] = op->cmd.opcode;
 322         xfers[xferpos].tx_buf = tmpbuf;
 323         xfers[xferpos].len = sizeof(op->cmd.opcode);
 324         xfers[xferpos].tx_nbits = op->cmd.buswidth;
 325         spi_message_add_tail(&xfers[xferpos], &msg);
 326         xferpos++;
 327         totalxferlen++;
 328 
 329         if (op->addr.nbytes) {
 330                 int i;
 331 
 332                 for (i = 0; i < op->addr.nbytes; i++)
 333                         tmpbuf[i + 1] = op->addr.val >>
 334                                         (8 * (op->addr.nbytes - i - 1));
 335 
 336                 xfers[xferpos].tx_buf = tmpbuf + 1;
 337                 xfers[xferpos].len = op->addr.nbytes;
 338                 xfers[xferpos].tx_nbits = op->addr.buswidth;
 339                 spi_message_add_tail(&xfers[xferpos], &msg);
 340                 xferpos++;
 341                 totalxferlen += op->addr.nbytes;
 342         }
 343 
 344         if (op->dummy.nbytes) {
 345                 memset(tmpbuf + op->addr.nbytes + 1, 0xff, op->dummy.nbytes);
 346                 xfers[xferpos].tx_buf = tmpbuf + op->addr.nbytes + 1;
 347                 xfers[xferpos].len = op->dummy.nbytes;
 348                 xfers[xferpos].tx_nbits = op->dummy.buswidth;
 349                 spi_message_add_tail(&xfers[xferpos], &msg);
 350                 xferpos++;
 351                 totalxferlen += op->dummy.nbytes;
 352         }
 353 
 354         if (op->data.nbytes) {
 355                 if (op->data.dir == SPI_MEM_DATA_IN) {
 356                         xfers[xferpos].rx_buf = op->data.buf.in;
 357                         xfers[xferpos].rx_nbits = op->data.buswidth;
 358                 } else {
 359                         xfers[xferpos].tx_buf = op->data.buf.out;
 360                         xfers[xferpos].tx_nbits = op->data.buswidth;
 361                 }
 362 
 363                 xfers[xferpos].len = op->data.nbytes;
 364                 spi_message_add_tail(&xfers[xferpos], &msg);
 365                 xferpos++;
 366                 totalxferlen += op->data.nbytes;
 367         }
 368 
 369         ret = spi_sync(mem->spi, &msg);
 370 
 371         kfree(tmpbuf);
 372 
 373         if (ret)
 374                 return ret;
 375 
 376         if (msg.actual_length != totalxferlen)
 377                 return -EIO;
 378 
 379         return 0;
 380 }
 381 EXPORT_SYMBOL_GPL(spi_mem_exec_op);
 382 
 383 /**
 384  * spi_mem_get_name() - Return the SPI mem device name to be used by the
 385  *                      upper layer if necessary
 386  * @mem: the SPI memory
 387  *
 388  * This function allows SPI mem users to retrieve the SPI mem device name.
 389  * It is useful if the upper layer needs to expose a custom name for
 390  * compatibility reasons.
 391  *
 392  * Return: a string containing the name of the memory device to be used
 393  *         by the SPI mem user
 394  */
 395 const char *spi_mem_get_name(struct spi_mem *mem)
 396 {
 397         return mem->name;
 398 }
 399 EXPORT_SYMBOL_GPL(spi_mem_get_name);
 400 
 401 /**
 402  * spi_mem_adjust_op_size() - Adjust the data size of a SPI mem operation to
 403  *                            match controller limitations
 404  * @mem: the SPI memory
 405  * @op: the operation to adjust
 406  *
 407  * Some controllers have FIFO limitations and must split a data transfer
 408  * operation into multiple ones, others require a specific alignment for
 409  * optimized accesses. This function allows SPI mem drivers to split a single
 410  * operation into multiple sub-operations when required.
 411  *
 412  * Return: a negative error code if the controller can't properly adjust @op,
 413  *         0 otherwise. Note that @op->data.nbytes will be updated if @op
 414  *         can't be handled in a single step.
 415  */
 416 int spi_mem_adjust_op_size(struct spi_mem *mem, struct spi_mem_op *op)
 417 {
 418         struct spi_controller *ctlr = mem->spi->controller;
 419         size_t len;
 420 
 421         len = sizeof(op->cmd.opcode) + op->addr.nbytes + op->dummy.nbytes;
 422 
 423         if (ctlr->mem_ops && ctlr->mem_ops->adjust_op_size)
 424                 return ctlr->mem_ops->adjust_op_size(mem, op);
 425 
 426         if (!ctlr->mem_ops || !ctlr->mem_ops->exec_op) {
 427                 if (len > spi_max_transfer_size(mem->spi))
 428                         return -EINVAL;
 429 
 430                 op->data.nbytes = min3((size_t)op->data.nbytes,
 431                                        spi_max_transfer_size(mem->spi),
 432                                        spi_max_message_size(mem->spi) -
 433                                        len);
 434                 if (!op->data.nbytes)
 435                         return -EINVAL;
 436         }
 437 
 438         return 0;
 439 }
 440 EXPORT_SYMBOL_GPL(spi_mem_adjust_op_size);
 441 
 442 static ssize_t spi_mem_no_dirmap_read(struct spi_mem_dirmap_desc *desc,
 443                                       u64 offs, size_t len, void *buf)
 444 {
 445         struct spi_mem_op op = desc->info.op_tmpl;
 446         int ret;
 447 
 448         op.addr.val = desc->info.offset + offs;
 449         op.data.buf.in = buf;
 450         op.data.nbytes = len;
 451         ret = spi_mem_adjust_op_size(desc->mem, &op);
 452         if (ret)
 453                 return ret;
 454 
 455         ret = spi_mem_exec_op(desc->mem, &op);
 456         if (ret)
 457                 return ret;
 458 
 459         return op.data.nbytes;
 460 }
 461 
 462 static ssize_t spi_mem_no_dirmap_write(struct spi_mem_dirmap_desc *desc,
 463                                        u64 offs, size_t len, const void *buf)
 464 {
 465         struct spi_mem_op op = desc->info.op_tmpl;
 466         int ret;
 467 
 468         op.addr.val = desc->info.offset + offs;
 469         op.data.buf.out = buf;
 470         op.data.nbytes = len;
 471         ret = spi_mem_adjust_op_size(desc->mem, &op);
 472         if (ret)
 473                 return ret;
 474 
 475         ret = spi_mem_exec_op(desc->mem, &op);
 476         if (ret)
 477                 return ret;
 478 
 479         return op.data.nbytes;
 480 }
 481 
 482 /**
 483  * spi_mem_dirmap_create() - Create a direct mapping descriptor
 484  * @mem: SPI mem device this direct mapping should be created for
 485  * @info: direct mapping information
 486  *
 487  * This function is creating a direct mapping descriptor which can then be used
 488  * to access the memory using spi_mem_dirmap_read() or spi_mem_dirmap_write().
 489  * If the SPI controller driver does not support direct mapping, this function
 490  * fallback to an implementation using spi_mem_exec_op(), so that the caller
 491  * doesn't have to bother implementing a fallback on his own.
 492  *
 493  * Return: a valid pointer in case of success, and ERR_PTR() otherwise.
 494  */
 495 struct spi_mem_dirmap_desc *
 496 spi_mem_dirmap_create(struct spi_mem *mem,
 497                       const struct spi_mem_dirmap_info *info)
 498 {
 499         struct spi_controller *ctlr = mem->spi->controller;
 500         struct spi_mem_dirmap_desc *desc;
 501         int ret = -ENOTSUPP;
 502 
 503         /* Make sure the number of address cycles is between 1 and 8 bytes. */
 504         if (!info->op_tmpl.addr.nbytes || info->op_tmpl.addr.nbytes > 8)
 505                 return ERR_PTR(-EINVAL);
 506 
 507         /* data.dir should either be SPI_MEM_DATA_IN or SPI_MEM_DATA_OUT. */
 508         if (info->op_tmpl.data.dir == SPI_MEM_NO_DATA)
 509                 return ERR_PTR(-EINVAL);
 510 
 511         desc = kzalloc(sizeof(*desc), GFP_KERNEL);
 512         if (!desc)
 513                 return ERR_PTR(-ENOMEM);
 514 
 515         desc->mem = mem;
 516         desc->info = *info;
 517         if (ctlr->mem_ops && ctlr->mem_ops->dirmap_create)
 518                 ret = ctlr->mem_ops->dirmap_create(desc);
 519 
 520         if (ret) {
 521                 desc->nodirmap = true;
 522                 if (!spi_mem_supports_op(desc->mem, &desc->info.op_tmpl))
 523                         ret = -ENOTSUPP;
 524                 else
 525                         ret = 0;
 526         }
 527 
 528         if (ret) {
 529                 kfree(desc);
 530                 return ERR_PTR(ret);
 531         }
 532 
 533         return desc;
 534 }
 535 EXPORT_SYMBOL_GPL(spi_mem_dirmap_create);
 536 
 537 /**
 538  * spi_mem_dirmap_destroy() - Destroy a direct mapping descriptor
 539  * @desc: the direct mapping descriptor to destroy
 540  *
 541  * This function destroys a direct mapping descriptor previously created by
 542  * spi_mem_dirmap_create().
 543  */
 544 void spi_mem_dirmap_destroy(struct spi_mem_dirmap_desc *desc)
 545 {
 546         struct spi_controller *ctlr = desc->mem->spi->controller;
 547 
 548         if (!desc->nodirmap && ctlr->mem_ops && ctlr->mem_ops->dirmap_destroy)
 549                 ctlr->mem_ops->dirmap_destroy(desc);
 550 
 551         kfree(desc);
 552 }
 553 EXPORT_SYMBOL_GPL(spi_mem_dirmap_destroy);
 554 
 555 static void devm_spi_mem_dirmap_release(struct device *dev, void *res)
 556 {
 557         struct spi_mem_dirmap_desc *desc = *(struct spi_mem_dirmap_desc **)res;
 558 
 559         spi_mem_dirmap_destroy(desc);
 560 }
 561 
 562 /**
 563  * devm_spi_mem_dirmap_create() - Create a direct mapping descriptor and attach
 564  *                                it to a device
 565  * @dev: device the dirmap desc will be attached to
 566  * @mem: SPI mem device this direct mapping should be created for
 567  * @info: direct mapping information
 568  *
 569  * devm_ variant of the spi_mem_dirmap_create() function. See
 570  * spi_mem_dirmap_create() for more details.
 571  *
 572  * Return: a valid pointer in case of success, and ERR_PTR() otherwise.
 573  */
 574 struct spi_mem_dirmap_desc *
 575 devm_spi_mem_dirmap_create(struct device *dev, struct spi_mem *mem,
 576                            const struct spi_mem_dirmap_info *info)
 577 {
 578         struct spi_mem_dirmap_desc **ptr, *desc;
 579 
 580         ptr = devres_alloc(devm_spi_mem_dirmap_release, sizeof(*ptr),
 581                            GFP_KERNEL);
 582         if (!ptr)
 583                 return ERR_PTR(-ENOMEM);
 584 
 585         desc = spi_mem_dirmap_create(mem, info);
 586         if (IS_ERR(desc)) {
 587                 devres_free(ptr);
 588         } else {
 589                 *ptr = desc;
 590                 devres_add(dev, ptr);
 591         }
 592 
 593         return desc;
 594 }
 595 EXPORT_SYMBOL_GPL(devm_spi_mem_dirmap_create);
 596 
 597 static int devm_spi_mem_dirmap_match(struct device *dev, void *res, void *data)
 598 {
 599         struct spi_mem_dirmap_desc **ptr = res;
 600 
 601         if (WARN_ON(!ptr || !*ptr))
 602                 return 0;
 603 
 604         return *ptr == data;
 605 }
 606 
 607 /**
 608  * devm_spi_mem_dirmap_destroy() - Destroy a direct mapping descriptor attached
 609  *                                 to a device
 610  * @dev: device the dirmap desc is attached to
 611  * @desc: the direct mapping descriptor to destroy
 612  *
 613  * devm_ variant of the spi_mem_dirmap_destroy() function. See
 614  * spi_mem_dirmap_destroy() for more details.
 615  */
 616 void devm_spi_mem_dirmap_destroy(struct device *dev,
 617                                  struct spi_mem_dirmap_desc *desc)
 618 {
 619         devres_release(dev, devm_spi_mem_dirmap_release,
 620                        devm_spi_mem_dirmap_match, desc);
 621 }
 622 EXPORT_SYMBOL_GPL(devm_spi_mem_dirmap_destroy);
 623 
 624 /**
 625  * spi_mem_dirmap_read() - Read data through a direct mapping
 626  * @desc: direct mapping descriptor
 627  * @offs: offset to start reading from. Note that this is not an absolute
 628  *        offset, but the offset within the direct mapping which already has
 629  *        its own offset
 630  * @len: length in bytes
 631  * @buf: destination buffer. This buffer must be DMA-able
 632  *
 633  * This function reads data from a memory device using a direct mapping
 634  * previously instantiated with spi_mem_dirmap_create().
 635  *
 636  * Return: the amount of data read from the memory device or a negative error
 637  * code. Note that the returned size might be smaller than @len, and the caller
 638  * is responsible for calling spi_mem_dirmap_read() again when that happens.
 639  */
 640 ssize_t spi_mem_dirmap_read(struct spi_mem_dirmap_desc *desc,
 641                             u64 offs, size_t len, void *buf)
 642 {
 643         struct spi_controller *ctlr = desc->mem->spi->controller;
 644         ssize_t ret;
 645 
 646         if (desc->info.op_tmpl.data.dir != SPI_MEM_DATA_IN)
 647                 return -EINVAL;
 648 
 649         if (!len)
 650                 return 0;
 651 
 652         if (desc->nodirmap) {
 653                 ret = spi_mem_no_dirmap_read(desc, offs, len, buf);
 654         } else if (ctlr->mem_ops && ctlr->mem_ops->dirmap_read) {
 655                 ret = spi_mem_access_start(desc->mem);
 656                 if (ret)
 657                         return ret;
 658 
 659                 ret = ctlr->mem_ops->dirmap_read(desc, offs, len, buf);
 660 
 661                 spi_mem_access_end(desc->mem);
 662         } else {
 663                 ret = -ENOTSUPP;
 664         }
 665 
 666         return ret;
 667 }
 668 EXPORT_SYMBOL_GPL(spi_mem_dirmap_read);
 669 
 670 /**
 671  * spi_mem_dirmap_write() - Write data through a direct mapping
 672  * @desc: direct mapping descriptor
 673  * @offs: offset to start writing from. Note that this is not an absolute
 674  *        offset, but the offset within the direct mapping which already has
 675  *        its own offset
 676  * @len: length in bytes
 677  * @buf: source buffer. This buffer must be DMA-able
 678  *
 679  * This function writes data to a memory device using a direct mapping
 680  * previously instantiated with spi_mem_dirmap_create().
 681  *
 682  * Return: the amount of data written to the memory device or a negative error
 683  * code. Note that the returned size might be smaller than @len, and the caller
 684  * is responsible for calling spi_mem_dirmap_write() again when that happens.
 685  */
 686 ssize_t spi_mem_dirmap_write(struct spi_mem_dirmap_desc *desc,
 687                              u64 offs, size_t len, const void *buf)
 688 {
 689         struct spi_controller *ctlr = desc->mem->spi->controller;
 690         ssize_t ret;
 691 
 692         if (desc->info.op_tmpl.data.dir != SPI_MEM_DATA_OUT)
 693                 return -EINVAL;
 694 
 695         if (!len)
 696                 return 0;
 697 
 698         if (desc->nodirmap) {
 699                 ret = spi_mem_no_dirmap_write(desc, offs, len, buf);
 700         } else if (ctlr->mem_ops && ctlr->mem_ops->dirmap_write) {
 701                 ret = spi_mem_access_start(desc->mem);
 702                 if (ret)
 703                         return ret;
 704 
 705                 ret = ctlr->mem_ops->dirmap_write(desc, offs, len, buf);
 706 
 707                 spi_mem_access_end(desc->mem);
 708         } else {
 709                 ret = -ENOTSUPP;
 710         }
 711 
 712         return ret;
 713 }
 714 EXPORT_SYMBOL_GPL(spi_mem_dirmap_write);
 715 
 716 static inline struct spi_mem_driver *to_spi_mem_drv(struct device_driver *drv)
 717 {
 718         return container_of(drv, struct spi_mem_driver, spidrv.driver);
 719 }
 720 
 721 static int spi_mem_probe(struct spi_device *spi)
 722 {
 723         struct spi_mem_driver *memdrv = to_spi_mem_drv(spi->dev.driver);
 724         struct spi_controller *ctlr = spi->controller;
 725         struct spi_mem *mem;
 726 
 727         mem = devm_kzalloc(&spi->dev, sizeof(*mem), GFP_KERNEL);
 728         if (!mem)
 729                 return -ENOMEM;
 730 
 731         mem->spi = spi;
 732 
 733         if (ctlr->mem_ops && ctlr->mem_ops->get_name)
 734                 mem->name = ctlr->mem_ops->get_name(mem);
 735         else
 736                 mem->name = dev_name(&spi->dev);
 737 
 738         if (IS_ERR_OR_NULL(mem->name))
 739                 return PTR_ERR(mem->name);
 740 
 741         spi_set_drvdata(spi, mem);
 742 
 743         return memdrv->probe(mem);
 744 }
 745 
 746 static int spi_mem_remove(struct spi_device *spi)
 747 {
 748         struct spi_mem_driver *memdrv = to_spi_mem_drv(spi->dev.driver);
 749         struct spi_mem *mem = spi_get_drvdata(spi);
 750 
 751         if (memdrv->remove)
 752                 return memdrv->remove(mem);
 753 
 754         return 0;
 755 }
 756 
 757 static void spi_mem_shutdown(struct spi_device *spi)
 758 {
 759         struct spi_mem_driver *memdrv = to_spi_mem_drv(spi->dev.driver);
 760         struct spi_mem *mem = spi_get_drvdata(spi);
 761 
 762         if (memdrv->shutdown)
 763                 memdrv->shutdown(mem);
 764 }
 765 
 766 /**
 767  * spi_mem_driver_register_with_owner() - Register a SPI memory driver
 768  * @memdrv: the SPI memory driver to register
 769  * @owner: the owner of this driver
 770  *
 771  * Registers a SPI memory driver.
 772  *
 773  * Return: 0 in case of success, a negative error core otherwise.
 774  */
 775 
 776 int spi_mem_driver_register_with_owner(struct spi_mem_driver *memdrv,
 777                                        struct module *owner)
 778 {
 779         memdrv->spidrv.probe = spi_mem_probe;
 780         memdrv->spidrv.remove = spi_mem_remove;
 781         memdrv->spidrv.shutdown = spi_mem_shutdown;
 782 
 783         return __spi_register_driver(owner, &memdrv->spidrv);
 784 }
 785 EXPORT_SYMBOL_GPL(spi_mem_driver_register_with_owner);
 786 
 787 /**
 788  * spi_mem_driver_unregister_with_owner() - Unregister a SPI memory driver
 789  * @memdrv: the SPI memory driver to unregister
 790  *
 791  * Unregisters a SPI memory driver.
 792  */
 793 void spi_mem_driver_unregister(struct spi_mem_driver *memdrv)
 794 {
 795         spi_unregister_driver(&memdrv->spidrv);
 796 }
 797 EXPORT_SYMBOL_GPL(spi_mem_driver_unregister);