spi-mem.c

   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/iopoll.h>
  10#include <linux/pm_runtime.h>
  11#include <linux/spi/spi.h>
  12#include <linux/spi/spi-mem.h>
  13#include <linux/sched/task_stack.h>
  14
  15#define CREATE_TRACE_POINTS
  16#include <trace/events/spi-mem.h>
  17
  18#include "internals.h"
  19
  20#define SPI_MEM_MAX_BUSWIDTH		8
  21
  22/**
  23 * spi_controller_dma_map_mem_op_data() - DMA-map the buffer attached to a
  24 *					  memory operation
  25 * @ctlr: the SPI controller requesting this dma_map()
  26 * @op: the memory operation containing the buffer to map
  27 * @sgt: a pointer to a non-initialized sg_table that will be filled by this
  28 *	 function
  29 *
  30 * Some controllers might want to do DMA on the data buffer embedded in @op.
  31 * This helper prepares everything for you and provides a ready-to-use
  32 * sg_table. This function is not intended to be called from spi drivers.
  33 * Only SPI controller drivers should use it.
  34 * Note that the caller must ensure the memory region pointed by
  35 * op->data.buf.{in,out} is DMA-able before calling this function.
  36 *
  37 * Return: 0 in case of success, a negative error code otherwise.
  38 */
  39int spi_controller_dma_map_mem_op_data(struct spi_controller *ctlr,
  40				       const struct spi_mem_op *op,
  41				       struct sg_table *sgt)
  42{
  43	struct device *dmadev;
  44
  45	if (!op->data.nbytes)
  46		return -EINVAL;
  47
  48	if (op->data.dir == SPI_MEM_DATA_OUT && ctlr->dma_tx)
  49		dmadev = ctlr->dma_tx->device->dev;
  50	else if (op->data.dir == SPI_MEM_DATA_IN && ctlr->dma_rx)
  51		dmadev = ctlr->dma_rx->device->dev;
  52	else
  53		dmadev = ctlr->dev.parent;
  54
  55	if (!dmadev)
  56		return -EINVAL;
  57
  58	return spi_map_buf(ctlr, dmadev, sgt, op->data.buf.in, op->data.nbytes,
  59			   op->data.dir == SPI_MEM_DATA_IN ?
  60			   DMA_FROM_DEVICE : DMA_TO_DEVICE);
  61}
  62EXPORT_SYMBOL_GPL(spi_controller_dma_map_mem_op_data);
  63
  64/**
  65 * spi_controller_dma_unmap_mem_op_data() - DMA-unmap the buffer attached to a
  66 *					    memory operation
  67 * @ctlr: the SPI controller requesting this dma_unmap()
  68 * @op: the memory operation containing the buffer to unmap
  69 * @sgt: a pointer to an sg_table previously initialized by
  70 *	 spi_controller_dma_map_mem_op_data()
  71 *
  72 * Some controllers might want to do DMA on the data buffer embedded in @op.
  73 * This helper prepares things so that the CPU can access the
  74 * op->data.buf.{in,out} buffer again.
  75 *
  76 * This function is not intended to be called from SPI drivers. Only SPI
  77 * controller drivers should use it.
  78 *
  79 * This function should be called after the DMA operation has finished and is
  80 * only valid if the previous spi_controller_dma_map_mem_op_data() call
  81 * returned 0.
  82 *
  83 * Return: 0 in case of success, a negative error code otherwise.
  84 */
  85void spi_controller_dma_unmap_mem_op_data(struct spi_controller *ctlr,
  86					  const struct spi_mem_op *op,
  87					  struct sg_table *sgt)
  88{
  89	struct device *dmadev;
  90
  91	if (!op->data.nbytes)
  92		return;
  93
  94	if (op->data.dir == SPI_MEM_DATA_OUT && ctlr->dma_tx)
  95		dmadev = ctlr->dma_tx->device->dev;
  96	else if (op->data.dir == SPI_MEM_DATA_IN && ctlr->dma_rx)
  97		dmadev = ctlr->dma_rx->device->dev;
  98	else
  99		dmadev = ctlr->dev.parent;
 100
 101	spi_unmap_buf(ctlr, dmadev, sgt,
 102		      op->data.dir == SPI_MEM_DATA_IN ?
 103		      DMA_FROM_DEVICE : DMA_TO_DEVICE);
 104}
 105EXPORT_SYMBOL_GPL(spi_controller_dma_unmap_mem_op_data);
 106
 107static int spi_check_buswidth_req(struct spi_mem *mem, u8 buswidth, bool tx)
 108{
 109	u32 mode = mem->spi->mode;
 110
 111	switch (buswidth) {
 112	case 1:
 113		return 0;
 114
 115	case 2:
 116		if ((tx &&
 117		     (mode & (SPI_TX_DUAL | SPI_TX_QUAD | SPI_TX_OCTAL))) ||
 118		    (!tx &&
 119		     (mode & (SPI_RX_DUAL | SPI_RX_QUAD | SPI_RX_OCTAL))))
 120			return 0;
 121
 122		break;
 123
 124	case 4:
 125		if ((tx && (mode & (SPI_TX_QUAD | SPI_TX_OCTAL))) ||
 126		    (!tx && (mode & (SPI_RX_QUAD | SPI_RX_OCTAL))))
 127			return 0;
 128
 129		break;
 130
 131	case 8:
 132		if ((tx && (mode & SPI_TX_OCTAL)) ||
 133		    (!tx && (mode & SPI_RX_OCTAL)))
 134			return 0;
 135
 136		break;
 137
 138	default:
 139		break;
 140	}
 141
 142	return -ENOTSUPP;
 143}
 144
 145static bool spi_mem_check_buswidth(struct spi_mem *mem,
 146				   const struct spi_mem_op *op)
 147{
 148	if (spi_check_buswidth_req(mem, op->cmd.buswidth, true))
 149		return false;
 150
 151	if (op->addr.nbytes &&
 152	    spi_check_buswidth_req(mem, op->addr.buswidth, true))
 153		return false;
 154
 155	if (op->dummy.nbytes &&
 156	    spi_check_buswidth_req(mem, op->dummy.buswidth, true))
 157		return false;
 158
 159	if (op->data.dir != SPI_MEM_NO_DATA &&
 160	    spi_check_buswidth_req(mem, op->data.buswidth,
 161				   op->data.dir == SPI_MEM_DATA_OUT))
 162		return false;
 163
 164	return true;
 165}
 166
 167bool spi_mem_default_supports_op(struct spi_mem *mem,
 168				 const struct spi_mem_op *op)
 169{
 170	struct spi_controller *ctlr = mem->spi->controller;
 171	bool op_is_dtr =
 172		op->cmd.dtr || op->addr.dtr || op->dummy.dtr || op->data.dtr;
 173
 174	if (op_is_dtr) {
 175		if (!spi_mem_controller_is_capable(ctlr, dtr))
 176			return false;
 177
 178		if (op->data.swap16 && !spi_mem_controller_is_capable(ctlr, swap16))
 179			return false;
 180
 181		/* Extra 8D-8D-8D limitations */
 182		if (op->cmd.dtr && op->cmd.buswidth == 8) {
 183			if (op->cmd.nbytes != 2)
 184				return false;
 185
 186			if ((op->addr.nbytes % 2) ||
 187			    (op->dummy.nbytes % 2) ||
 188			    (op->data.nbytes % 2)) {
 189				dev_err(&ctlr->dev,
 190					"Even byte numbers not allowed in octal DTR operations\n");
 191				return false;
 192			}
 193		}
 194	} else {
 195		if (op->cmd.nbytes != 1)
 196			return false;
 197	}
 198
 199	if (op->data.ecc) {
 200		if (!spi_mem_controller_is_capable(ctlr, ecc))
 201			return false;
 202	}
 203
 204	if (op->max_freq && mem->spi->controller->min_speed_hz &&
 205	    op->max_freq < mem->spi->controller->min_speed_hz)
 206		return false;
 207
 208	if (op->max_freq &&
 209	    op->max_freq < mem->spi->max_speed_hz) {
 210		if (!spi_mem_controller_is_capable(ctlr, per_op_freq))
 211			return false;
 212	}
 213
 214	return spi_mem_check_buswidth(mem, op);
 215}
 216EXPORT_SYMBOL_GPL(spi_mem_default_supports_op);
 217
 218static bool spi_mem_buswidth_is_valid(u8 buswidth)
 219{
 220	if (hweight8(buswidth) > 1 || buswidth > SPI_MEM_MAX_BUSWIDTH)
 221		return false;
 222
 223	return true;
 224}
 225
 226static int spi_mem_check_op(const struct spi_mem_op *op)
 227{
 228	if (!op->cmd.buswidth || !op->cmd.nbytes)
 229		return -EINVAL;
 230
 231	if ((op->addr.nbytes && !op->addr.buswidth) ||
 232	    (op->dummy.nbytes && !op->dummy.buswidth) ||
 233	    (op->data.nbytes && !op->data.buswidth))
 234		return -EINVAL;
 235
 236	if (!spi_mem_buswidth_is_valid(op->cmd.buswidth) ||
 237	    !spi_mem_buswidth_is_valid(op->addr.buswidth) ||
 238	    !spi_mem_buswidth_is_valid(op->dummy.buswidth) ||
 239	    !spi_mem_buswidth_is_valid(op->data.buswidth))
 240		return -EINVAL;
 241
 242	/* Buffers must be DMA-able. */
 243	if (WARN_ON_ONCE(op->data.dir == SPI_MEM_DATA_IN &&
 244			 object_is_on_stack(op->data.buf.in)))
 245		return -EINVAL;
 246
 247	if (WARN_ON_ONCE(op->data.dir == SPI_MEM_DATA_OUT &&
 248			 object_is_on_stack(op->data.buf.out)))
 249		return -EINVAL;
 250
 251	return 0;
 252}
 253
 254static bool spi_mem_internal_supports_op(struct spi_mem *mem,
 255					 const struct spi_mem_op *op)
 256{
 257	struct spi_controller *ctlr = mem->spi->controller;
 258
 259	if (ctlr->mem_ops && ctlr->mem_ops->supports_op)
 260		return ctlr->mem_ops->supports_op(mem, op);
 261
 262	return spi_mem_default_supports_op(mem, op);
 263}
 264
 265/**
 266 * spi_mem_supports_op() - Check if a memory device and the controller it is
 267 *			   connected to support a specific memory operation
 268 * @mem: the SPI memory
 269 * @op: the memory operation to check
 270 *
 271 * Some controllers are only supporting Single or Dual IOs, others might only
 272 * support specific opcodes, or it can even be that the controller and device
 273 * both support Quad IOs but the hardware prevents you from using it because
 274 * only 2 IO lines are connected.
 275 *
 276 * This function checks whether a specific operation is supported.
 277 *
 278 * Return: true if @op is supported, false otherwise.
 279 */
 280bool spi_mem_supports_op(struct spi_mem *mem, const struct spi_mem_op *op)
 281{
 282	/* Make sure the operation frequency is correct before going futher */
 283	spi_mem_adjust_op_freq(mem, (struct spi_mem_op *)op);
 284
 285	if (spi_mem_check_op(op))
 286		return false;
 287
 288	return spi_mem_internal_supports_op(mem, op);
 289}
 290EXPORT_SYMBOL_GPL(spi_mem_supports_op);
 291
 292static int spi_mem_access_start(struct spi_mem *mem)
 293{
 294	struct spi_controller *ctlr = mem->spi->controller;
 295
 296	/*
 297	 * Flush the message queue before executing our SPI memory
 298	 * operation to prevent preemption of regular SPI transfers.
 299	 */
 300	spi_flush_queue(ctlr);
 301
 302	if (ctlr->auto_runtime_pm) {
 303		int ret;
 304
 305		ret = pm_runtime_resume_and_get(ctlr->dev.parent);
 306		if (ret < 0) {
 307			dev_err(&ctlr->dev, "Failed to power device: %d\n",
 308				ret);
 309			return ret;
 310		}
 311	}
 312
 313	mutex_lock(&ctlr->bus_lock_mutex);
 314	mutex_lock(&ctlr->io_mutex);
 315
 316	return 0;
 317}
 318
 319static void spi_mem_access_end(struct spi_mem *mem)
 320{
 321	struct spi_controller *ctlr = mem->spi->controller;
 322
 323	mutex_unlock(&ctlr->io_mutex);
 324	mutex_unlock(&ctlr->bus_lock_mutex);
 325
 326	if (ctlr->auto_runtime_pm)
 327		pm_runtime_put(ctlr->dev.parent);
 328}
 329
 330static void spi_mem_add_op_stats(struct spi_statistics __percpu *pcpu_stats,
 331				 const struct spi_mem_op *op, int exec_op_ret)
 332{
 333	struct spi_statistics *stats;
 334	u64 len, l2len;
 335
 336	get_cpu();
 337	stats = this_cpu_ptr(pcpu_stats);
 338	u64_stats_update_begin(&stats->syncp);
 339
 340	/*
 341	 * We do not have the concept of messages or transfers. Let's consider
 342	 * that one operation is equivalent to one message and one transfer.
 343	 */
 344	u64_stats_inc(&stats->messages);
 345	u64_stats_inc(&stats->transfers);
 346
 347	/* Use the sum of all lengths as bytes count and histogram value. */
 348	len = op->cmd.nbytes + op->addr.nbytes;
 349	len += op->dummy.nbytes + op->data.nbytes;
 350	u64_stats_add(&stats->bytes, len);
 351	l2len = min(fls(len), SPI_STATISTICS_HISTO_SIZE) - 1;
 352	u64_stats_inc(&stats->transfer_bytes_histo[l2len]);
 353
 354	/* Only account for data bytes as transferred bytes. */
 355	if (op->data.nbytes && op->data.dir == SPI_MEM_DATA_OUT)
 356		u64_stats_add(&stats->bytes_tx, op->data.nbytes);
 357	if (op->data.nbytes && op->data.dir == SPI_MEM_DATA_IN)
 358		u64_stats_add(&stats->bytes_rx, op->data.nbytes);
 359
 360	/*
 361	 * A timeout is not an error, following the same behavior as
 362	 * spi_transfer_one_message().
 363	 */
 364	if (exec_op_ret == -ETIMEDOUT)
 365		u64_stats_inc(&stats->timedout);
 366	else if (exec_op_ret)
 367		u64_stats_inc(&stats->errors);
 368
 369	u64_stats_update_end(&stats->syncp);
 370	put_cpu();
 371}
 372
 373/**
 374 * spi_mem_exec_op() - Execute a memory operation
 375 * @mem: the SPI memory
 376 * @op: the memory operation to execute
 377 *
 378 * Executes a memory operation.
 379 *
 380 * This function first checks that @op is supported and then tries to execute
 381 * it.
 382 *
 383 * Return: 0 in case of success, a negative error code otherwise.
 384 */
 385int spi_mem_exec_op(struct spi_mem *mem, const struct spi_mem_op *op)
 386{
 387	unsigned int tmpbufsize, xferpos = 0, totalxferlen = 0;
 388	struct spi_controller *ctlr = mem->spi->controller;
 389	struct spi_transfer xfers[4] = { };
 390	struct spi_message msg;
 391	u8 *tmpbuf;
 392	int ret;
 393
 394	/* Make sure the operation frequency is correct before going futher */
 395	spi_mem_adjust_op_freq(mem, (struct spi_mem_op *)op);
 396
 397	dev_vdbg(&mem->spi->dev, "[cmd: 0x%02x][%dB addr: %#8llx][%2dB dummy][%4dB data %s] %d%c-%d%c-%d%c-%d%c @ %uHz\n",
 398		 op->cmd.opcode,
 399		 op->addr.nbytes, (op->addr.nbytes ? op->addr.val : 0),
 400		 op->dummy.nbytes,
 401		 op->data.nbytes, (op->data.nbytes ? (op->data.dir == SPI_MEM_DATA_IN ? " read" : "write") : "     "),
 402		 op->cmd.buswidth, op->cmd.dtr ? 'D' : 'S',
 403		 op->addr.buswidth, op->addr.dtr ? 'D' : 'S',
 404		 op->dummy.buswidth, op->dummy.dtr ? 'D' : 'S',
 405		 op->data.buswidth, op->data.dtr ? 'D' : 'S',
 406		 op->max_freq ? op->max_freq : mem->spi->max_speed_hz);
 407
 408	ret = spi_mem_check_op(op);
 409	if (ret)
 410		return ret;
 411
 412	if (!spi_mem_internal_supports_op(mem, op))
 413		return -EOPNOTSUPP;
 414
 415	if (ctlr->mem_ops && ctlr->mem_ops->exec_op && !spi_get_csgpiod(mem->spi, 0)) {
 416		ret = spi_mem_access_start(mem);
 417		if (ret)
 418			return ret;
 419
 420		trace_spi_mem_start_op(mem, op);
 421		ret = ctlr->mem_ops->exec_op(mem, op);
 422		trace_spi_mem_stop_op(mem, op);
 423
 424		spi_mem_access_end(mem);
 425
 426		/*
 427		 * Some controllers only optimize specific paths (typically the
 428		 * read path) and expect the core to use the regular SPI
 429		 * interface in other cases.
 430		 */
 431		if (!ret || (ret != -ENOTSUPP && ret != -EOPNOTSUPP)) {
 432			spi_mem_add_op_stats(ctlr->pcpu_statistics, op, ret);
 433			spi_mem_add_op_stats(mem->spi->pcpu_statistics, op, ret);
 434
 435			return ret;
 436		}
 437	}
 438
 439	tmpbufsize = op->cmd.nbytes + op->addr.nbytes + op->dummy.nbytes;
 440
 441	/*
 442	 * Allocate a buffer to transmit the CMD, ADDR cycles with kmalloc() so
 443	 * we're guaranteed that this buffer is DMA-able, as required by the
 444	 * SPI layer.
 445	 */
 446	tmpbuf = kzalloc(tmpbufsize, GFP_KERNEL | GFP_DMA);
 447	if (!tmpbuf)
 448		return -ENOMEM;
 449
 450	spi_message_init(&msg);
 451
 452	tmpbuf[0] = op->cmd.opcode;
 453	xfers[xferpos].tx_buf = tmpbuf;
 454	xfers[xferpos].len = op->cmd.nbytes;
 455	xfers[xferpos].tx_nbits = op->cmd.buswidth;
 456	xfers[xferpos].speed_hz = op->max_freq;
 457	spi_message_add_tail(&xfers[xferpos], &msg);
 458	xferpos++;
 459	totalxferlen++;
 460
 461	if (op->addr.nbytes) {
 462		int i;
 463
 464		for (i = 0; i < op->addr.nbytes; i++)
 465			tmpbuf[i + 1] = op->addr.val >>
 466					(8 * (op->addr.nbytes - i - 1));
 467
 468		xfers[xferpos].tx_buf = tmpbuf + 1;
 469		xfers[xferpos].len = op->addr.nbytes;
 470		xfers[xferpos].tx_nbits = op->addr.buswidth;
 471		xfers[xferpos].speed_hz = op->max_freq;
 472		spi_message_add_tail(&xfers[xferpos], &msg);
 473		xferpos++;
 474		totalxferlen += op->addr.nbytes;
 475	}
 476
 477	if (op->dummy.nbytes) {
 478		memset(tmpbuf + op->addr.nbytes + 1, 0xff, op->dummy.nbytes);
 479		xfers[xferpos].tx_buf = tmpbuf + op->addr.nbytes + 1;
 480		xfers[xferpos].len = op->dummy.nbytes;
 481		xfers[xferpos].tx_nbits = op->dummy.buswidth;
 482		xfers[xferpos].dummy_data = 1;
 483		xfers[xferpos].speed_hz = op->max_freq;
 484		spi_message_add_tail(&xfers[xferpos], &msg);
 485		xferpos++;
 486		totalxferlen += op->dummy.nbytes;
 487	}
 488
 489	if (op->data.nbytes) {
 490		if (op->data.dir == SPI_MEM_DATA_IN) {
 491			xfers[xferpos].rx_buf = op->data.buf.in;
 492			xfers[xferpos].rx_nbits = op->data.buswidth;
 493		} else {
 494			xfers[xferpos].tx_buf = op->data.buf.out;
 495			xfers[xferpos].tx_nbits = op->data.buswidth;
 496		}
 497
 498		xfers[xferpos].len = op->data.nbytes;
 499		xfers[xferpos].speed_hz = op->max_freq;
 500		spi_message_add_tail(&xfers[xferpos], &msg);
 501		xferpos++;
 502		totalxferlen += op->data.nbytes;
 503	}
 504
 505	ret = spi_sync(mem->spi, &msg);
 506
 507	kfree(tmpbuf);
 508
 509	if (ret)
 510		return ret;
 511
 512	if (msg.actual_length != totalxferlen)
 513		return -EIO;
 514
 515	return 0;
 516}
 517EXPORT_SYMBOL_GPL(spi_mem_exec_op);
 518
 519/**
 520 * spi_mem_get_name() - Return the SPI mem device name to be used by the
 521 *			upper layer if necessary
 522 * @mem: the SPI memory
 523 *
 524 * This function allows SPI mem users to retrieve the SPI mem device name.
 525 * It is useful if the upper layer needs to expose a custom name for
 526 * compatibility reasons.
 527 *
 528 * Return: a string containing the name of the memory device to be used
 529 *	   by the SPI mem user
 530 */
 531const char *spi_mem_get_name(struct spi_mem *mem)
 532{
 533	return mem->name;
 534}
 535EXPORT_SYMBOL_GPL(spi_mem_get_name);
 536
 537/**
 538 * spi_mem_adjust_op_size() - Adjust the data size of a SPI mem operation to
 539 *			      match controller limitations
 540 * @mem: the SPI memory
 541 * @op: the operation to adjust
 542 *
 543 * Some controllers have FIFO limitations and must split a data transfer
 544 * operation into multiple ones, others require a specific alignment for
 545 * optimized accesses. This function allows SPI mem drivers to split a single
 546 * operation into multiple sub-operations when required.
 547 *
 548 * Return: a negative error code if the controller can't properly adjust @op,
 549 *	   0 otherwise. Note that @op->data.nbytes will be updated if @op
 550 *	   can't be handled in a single step.
 551 */
 552int spi_mem_adjust_op_size(struct spi_mem *mem, struct spi_mem_op *op)
 553{
 554	struct spi_controller *ctlr = mem->spi->controller;
 555	size_t len;
 556
 557	if (ctlr->mem_ops && ctlr->mem_ops->adjust_op_size)
 558		return ctlr->mem_ops->adjust_op_size(mem, op);
 559
 560	if (!ctlr->mem_ops || !ctlr->mem_ops->exec_op) {
 561		len = op->cmd.nbytes + op->addr.nbytes + op->dummy.nbytes;
 562
 563		if (len > spi_max_transfer_size(mem->spi))
 564			return -EINVAL;
 565
 566		op->data.nbytes = min3((size_t)op->data.nbytes,
 567				       spi_max_transfer_size(mem->spi),
 568				       spi_max_message_size(mem->spi) -
 569				       len);
 570		if (!op->data.nbytes)
 571			return -EINVAL;
 572	}
 573
 574	return 0;
 575}
 576EXPORT_SYMBOL_GPL(spi_mem_adjust_op_size);
 577
 578/**
 579 * spi_mem_adjust_op_freq() - Adjust the frequency of a SPI mem operation to
 580 *			      match controller, PCB and chip limitations
 581 * @mem: the SPI memory
 582 * @op: the operation to adjust
 583 *
 584 * Some chips have per-op frequency limitations and must adapt the maximum
 585 * speed. This function allows SPI mem drivers to set @op->max_freq to the
 586 * maximum supported value.
 587 */
 588void spi_mem_adjust_op_freq(struct spi_mem *mem, struct spi_mem_op *op)
 589{
 590	if (!op->max_freq || op->max_freq > mem->spi->max_speed_hz)
 591		op->max_freq = mem->spi->max_speed_hz;
 592}
 593EXPORT_SYMBOL_GPL(spi_mem_adjust_op_freq);
 594
 595/**
 596 * spi_mem_calc_op_duration() - Derives the theoretical length (in ns) of an
 597 *			        operation. This helps finding the best variant
 598 *			        among a list of possible choices.
 599 * @mem: the SPI memory
 600 * @op: the operation to benchmark
 601 *
 602 * Some chips have per-op frequency limitations, PCBs usually have their own
 603 * limitations as well, and controllers can support dual, quad or even octal
 604 * modes, sometimes in DTR. All these combinations make it impossible to
 605 * statically list the best combination for all situations. If we want something
 606 * accurate, all these combinations should be rated (eg. with a time estimate)
 607 * and the best pick should be taken based on these calculations.
 608 *
 609 * Returns a ns estimate for the time this op would take, except if no
 610 * frequency limit has been set, in this case we return the number of
 611 * cycles nevertheless to allow callers to distinguish which operation
 612 * would be the fastest at iso-frequency.
 613 */
 614u64 spi_mem_calc_op_duration(struct spi_mem *mem, struct spi_mem_op *op)
 615{
 616	u64 ncycles = 0;
 617	u64 ps_per_cycles, duration;
 618
 619	spi_mem_adjust_op_freq(mem, op);
 620
 621	if (op->max_freq) {
 622		ps_per_cycles = 1000000000000ULL;
 623		do_div(ps_per_cycles, op->max_freq);
 624	} else {
 625		/* In this case, the unit is no longer a time unit */
 626		ps_per_cycles = 1;
 627	}
 628
 629	ncycles += ((op->cmd.nbytes * 8) / op->cmd.buswidth) / (op->cmd.dtr ? 2 : 1);
 630	ncycles += ((op->addr.nbytes * 8) / op->addr.buswidth) / (op->addr.dtr ? 2 : 1);
 631
 632	/* Dummy bytes are optional for some SPI flash memory operations */
 633	if (op->dummy.nbytes)
 634		ncycles += ((op->dummy.nbytes * 8) / op->dummy.buswidth) / (op->dummy.dtr ? 2 : 1);
 635
 636	ncycles += ((op->data.nbytes * 8) / op->data.buswidth) / (op->data.dtr ? 2 : 1);
 637
 638	/* Derive the duration in ps */
 639	duration = ncycles * ps_per_cycles;
 640	/* Convert into ns */
 641	do_div(duration, 1000);
 642
 643	return duration;
 644}
 645EXPORT_SYMBOL_GPL(spi_mem_calc_op_duration);
 646
 647static ssize_t spi_mem_no_dirmap_read(struct spi_mem_dirmap_desc *desc,
 648				      u64 offs, size_t len, void *buf)
 649{
 650	struct spi_mem_op op = desc->info.op_tmpl;
 651	int ret;
 652
 653	op.addr.val = desc->info.offset + offs;
 654	op.data.buf.in = buf;
 655	op.data.nbytes = len;
 656	ret = spi_mem_adjust_op_size(desc->mem, &op);
 657	if (ret)
 658		return ret;
 659
 660	ret = spi_mem_exec_op(desc->mem, &op);
 661	if (ret)
 662		return ret;
 663
 664	return op.data.nbytes;
 665}
 666
 667static ssize_t spi_mem_no_dirmap_write(struct spi_mem_dirmap_desc *desc,
 668				       u64 offs, size_t len, const void *buf)
 669{
 670	struct spi_mem_op op = desc->info.op_tmpl;
 671	int ret;
 672
 673	op.addr.val = desc->info.offset + offs;
 674	op.data.buf.out = buf;
 675	op.data.nbytes = len;
 676	ret = spi_mem_adjust_op_size(desc->mem, &op);
 677	if (ret)
 678		return ret;
 679
 680	ret = spi_mem_exec_op(desc->mem, &op);
 681	if (ret)
 682		return ret;
 683
 684	return op.data.nbytes;
 685}
 686
 687/**
 688 * spi_mem_dirmap_create() - Create a direct mapping descriptor
 689 * @mem: SPI mem device this direct mapping should be created for
 690 * @info: direct mapping information
 691 *
 692 * This function is creating a direct mapping descriptor which can then be used
 693 * to access the memory using spi_mem_dirmap_read() or spi_mem_dirmap_write().
 694 * If the SPI controller driver does not support direct mapping, this function
 695 * falls back to an implementation using spi_mem_exec_op(), so that the caller
 696 * doesn't have to bother implementing a fallback on his own.
 697 *
 698 * Return: a valid pointer in case of success, and ERR_PTR() otherwise.
 699 */
 700struct spi_mem_dirmap_desc *
 701spi_mem_dirmap_create(struct spi_mem *mem,
 702		      const struct spi_mem_dirmap_info *info)
 703{
 704	struct spi_controller *ctlr = mem->spi->controller;
 705	struct spi_mem_dirmap_desc *desc;
 706	int ret = -ENOTSUPP;
 707
 708	/* Make sure the number of address cycles is between 1 and 8 bytes. */
 709	if (!info->op_tmpl.addr.nbytes || info->op_tmpl.addr.nbytes > 8)
 710		return ERR_PTR(-EINVAL);
 711
 712	/* data.dir should either be SPI_MEM_DATA_IN or SPI_MEM_DATA_OUT. */
 713	if (info->op_tmpl.data.dir == SPI_MEM_NO_DATA)
 714		return ERR_PTR(-EINVAL);
 715
 716	desc = kzalloc(sizeof(*desc), GFP_KERNEL);
 717	if (!desc)
 718		return ERR_PTR(-ENOMEM);
 719
 720	desc->mem = mem;
 721	desc->info = *info;
 722	if (ctlr->mem_ops && ctlr->mem_ops->dirmap_create) {
 723		ret = spi_mem_access_start(mem);
 724		if (ret) {
 725			kfree(desc);
 726			return ERR_PTR(ret);
 727		}
 728
 729		ret = ctlr->mem_ops->dirmap_create(desc);
 730
 731		spi_mem_access_end(mem);
 732	}
 733
 734	if (ret) {
 735		desc->nodirmap = true;
 736		if (!spi_mem_supports_op(desc->mem, &desc->info.op_tmpl))
 737			ret = -EOPNOTSUPP;
 738		else
 739			ret = 0;
 740	}
 741
 742	if (ret) {
 743		kfree(desc);
 744		return ERR_PTR(ret);
 745	}
 746
 747	return desc;
 748}
 749EXPORT_SYMBOL_GPL(spi_mem_dirmap_create);
 750
 751/**
 752 * spi_mem_dirmap_destroy() - Destroy a direct mapping descriptor
 753 * @desc: the direct mapping descriptor to destroy
 754 *
 755 * This function destroys a direct mapping descriptor previously created by
 756 * spi_mem_dirmap_create().
 757 */
 758void spi_mem_dirmap_destroy(struct spi_mem_dirmap_desc *desc)
 759{
 760	struct spi_controller *ctlr = desc->mem->spi->controller;
 761
 762	if (!desc->nodirmap && ctlr->mem_ops && ctlr->mem_ops->dirmap_destroy)
 763		ctlr->mem_ops->dirmap_destroy(desc);
 764
 765	kfree(desc);
 766}
 767EXPORT_SYMBOL_GPL(spi_mem_dirmap_destroy);
 768
 769static void devm_spi_mem_dirmap_release(struct device *dev, void *res)
 770{
 771	struct spi_mem_dirmap_desc *desc = *(struct spi_mem_dirmap_desc **)res;
 772
 773	spi_mem_dirmap_destroy(desc);
 774}
 775
 776/**
 777 * devm_spi_mem_dirmap_create() - Create a direct mapping descriptor and attach
 778 *				  it to a device
 779 * @dev: device the dirmap desc will be attached to
 780 * @mem: SPI mem device this direct mapping should be created for
 781 * @info: direct mapping information
 782 *
 783 * devm_ variant of the spi_mem_dirmap_create() function. See
 784 * spi_mem_dirmap_create() for more details.
 785 *
 786 * Return: a valid pointer in case of success, and ERR_PTR() otherwise.
 787 */
 788struct spi_mem_dirmap_desc *
 789devm_spi_mem_dirmap_create(struct device *dev, struct spi_mem *mem,
 790			   const struct spi_mem_dirmap_info *info)
 791{
 792	struct spi_mem_dirmap_desc **ptr, *desc;
 793
 794	ptr = devres_alloc(devm_spi_mem_dirmap_release, sizeof(*ptr),
 795			   GFP_KERNEL);
 796	if (!ptr)
 797		return ERR_PTR(-ENOMEM);
 798
 799	desc = spi_mem_dirmap_create(mem, info);
 800	if (IS_ERR(desc)) {
 801		devres_free(ptr);
 802	} else {
 803		*ptr = desc;
 804		devres_add(dev, ptr);
 805	}
 806
 807	return desc;
 808}
 809EXPORT_SYMBOL_GPL(devm_spi_mem_dirmap_create);
 810
 811static int devm_spi_mem_dirmap_match(struct device *dev, void *res, void *data)
 812{
 813	struct spi_mem_dirmap_desc **ptr = res;
 814
 815	if (WARN_ON(!ptr || !*ptr))
 816		return 0;
 817
 818	return *ptr == data;
 819}
 820
 821/**
 822 * devm_spi_mem_dirmap_destroy() - Destroy a direct mapping descriptor attached
 823 *				   to a device
 824 * @dev: device the dirmap desc is attached to
 825 * @desc: the direct mapping descriptor to destroy
 826 *
 827 * devm_ variant of the spi_mem_dirmap_destroy() function. See
 828 * spi_mem_dirmap_destroy() for more details.
 829 */
 830void devm_spi_mem_dirmap_destroy(struct device *dev,
 831				 struct spi_mem_dirmap_desc *desc)
 832{
 833	devres_release(dev, devm_spi_mem_dirmap_release,
 834		       devm_spi_mem_dirmap_match, desc);
 835}
 836EXPORT_SYMBOL_GPL(devm_spi_mem_dirmap_destroy);
 837
 838/**
 839 * spi_mem_dirmap_read() - Read data through a direct mapping
 840 * @desc: direct mapping descriptor
 841 * @offs: offset to start reading from. Note that this is not an absolute
 842 *	  offset, but the offset within the direct mapping which already has
 843 *	  its own offset
 844 * @len: length in bytes
 845 * @buf: destination buffer. This buffer must be DMA-able
 846 *
 847 * This function reads data from a memory device using a direct mapping
 848 * previously instantiated with spi_mem_dirmap_create().
 849 *
 850 * Return: the amount of data read from the memory device or a negative error
 851 * code. Note that the returned size might be smaller than @len, and the caller
 852 * is responsible for calling spi_mem_dirmap_read() again when that happens.
 853 */
 854ssize_t spi_mem_dirmap_read(struct spi_mem_dirmap_desc *desc,
 855			    u64 offs, size_t len, void *buf)
 856{
 857	struct spi_controller *ctlr = desc->mem->spi->controller;
 858	ssize_t ret;
 859
 860	if (desc->info.op_tmpl.data.dir != SPI_MEM_DATA_IN)
 861		return -EINVAL;
 862
 863	if (!len)
 864		return 0;
 865
 866	if (desc->nodirmap) {
 867		ret = spi_mem_no_dirmap_read(desc, offs, len, buf);
 868	} else if (ctlr->mem_ops && ctlr->mem_ops->dirmap_read) {
 869		ret = spi_mem_access_start(desc->mem);
 870		if (ret)
 871			return ret;
 872
 873		ret = ctlr->mem_ops->dirmap_read(desc, offs, len, buf);
 874
 875		spi_mem_access_end(desc->mem);
 876	} else {
 877		ret = -ENOTSUPP;
 878	}
 879
 880	return ret;
 881}
 882EXPORT_SYMBOL_GPL(spi_mem_dirmap_read);
 883
 884/**
 885 * spi_mem_dirmap_write() - Write data through a direct mapping
 886 * @desc: direct mapping descriptor
 887 * @offs: offset to start writing from. Note that this is not an absolute
 888 *	  offset, but the offset within the direct mapping which already has
 889 *	  its own offset
 890 * @len: length in bytes
 891 * @buf: source buffer. This buffer must be DMA-able
 892 *
 893 * This function writes data to a memory device using a direct mapping
 894 * previously instantiated with spi_mem_dirmap_create().
 895 *
 896 * Return: the amount of data written to the memory device or a negative error
 897 * code. Note that the returned size might be smaller than @len, and the caller
 898 * is responsible for calling spi_mem_dirmap_write() again when that happens.
 899 */
 900ssize_t spi_mem_dirmap_write(struct spi_mem_dirmap_desc *desc,
 901			     u64 offs, size_t len, const void *buf)
 902{
 903	struct spi_controller *ctlr = desc->mem->spi->controller;
 904	ssize_t ret;
 905
 906	if (desc->info.op_tmpl.data.dir != SPI_MEM_DATA_OUT)
 907		return -EINVAL;
 908
 909	if (!len)
 910		return 0;
 911
 912	if (desc->nodirmap) {
 913		ret = spi_mem_no_dirmap_write(desc, offs, len, buf);
 914	} else if (ctlr->mem_ops && ctlr->mem_ops->dirmap_write) {
 915		ret = spi_mem_access_start(desc->mem);
 916		if (ret)
 917			return ret;
 918
 919		ret = ctlr->mem_ops->dirmap_write(desc, offs, len, buf);
 920
 921		spi_mem_access_end(desc->mem);
 922	} else {
 923		ret = -ENOTSUPP;
 924	}
 925
 926	return ret;
 927}
 928EXPORT_SYMBOL_GPL(spi_mem_dirmap_write);
 929
 930static inline struct spi_mem_driver *to_spi_mem_drv(struct device_driver *drv)
 931{
 932	return container_of(drv, struct spi_mem_driver, spidrv.driver);
 933}
 934
 935static int spi_mem_read_status(struct spi_mem *mem,
 936			       const struct spi_mem_op *op,
 937			       u16 *status)
 938{
 939	const u8 *bytes = (u8 *)op->data.buf.in;
 940	int ret;
 941
 942	ret = spi_mem_exec_op(mem, op);
 943	if (ret)
 944		return ret;
 945
 946	if (op->data.nbytes > 1)
 947		*status = ((u16)bytes[0] << 8) | bytes[1];
 948	else
 949		*status = bytes[0];
 950
 951	return 0;
 952}
 953
 954/**
 955 * spi_mem_poll_status() - Poll memory device status
 956 * @mem: SPI memory device
 957 * @op: the memory operation to execute
 958 * @mask: status bitmask to ckeck
 959 * @match: (status & mask) expected value
 960 * @initial_delay_us: delay in us before starting to poll
 961 * @polling_delay_us: time to sleep between reads in us
 962 * @timeout_ms: timeout in milliseconds
 963 *
 964 * This function polls a status register and returns when
 965 * (status & mask) == match or when the timeout has expired.
 966 *
 967 * Return: 0 in case of success, -ETIMEDOUT in case of error,
 968 *         -EOPNOTSUPP if not supported.
 969 */
 970int spi_mem_poll_status(struct spi_mem *mem,
 971			const struct spi_mem_op *op,
 972			u16 mask, u16 match,
 973			unsigned long initial_delay_us,
 974			unsigned long polling_delay_us,
 975			u16 timeout_ms)
 976{
 977	struct spi_controller *ctlr = mem->spi->controller;
 978	int ret = -EOPNOTSUPP;
 979	int read_status_ret;
 980	u16 status;
 981
 982	if (op->data.nbytes < 1 || op->data.nbytes > 2 ||
 983	    op->data.dir != SPI_MEM_DATA_IN)
 984		return -EINVAL;
 985
 986	if (ctlr->mem_ops && ctlr->mem_ops->poll_status && !spi_get_csgpiod(mem->spi, 0)) {
 987		ret = spi_mem_access_start(mem);
 988		if (ret)
 989			return ret;
 990
 991		ret = ctlr->mem_ops->poll_status(mem, op, mask, match,
 992						 initial_delay_us, polling_delay_us,
 993						 timeout_ms);
 994
 995		spi_mem_access_end(mem);
 996	}
 997
 998	if (ret == -EOPNOTSUPP) {
 999		if (!spi_mem_supports_op(mem, op))
1000			return ret;
1001
1002		if (initial_delay_us < 10)
1003			udelay(initial_delay_us);
1004		else
1005			usleep_range((initial_delay_us >> 2) + 1,
1006				     initial_delay_us);
1007
1008		ret = read_poll_timeout(spi_mem_read_status, read_status_ret,
1009					(read_status_ret || ((status) & mask) == match),
1010					polling_delay_us, timeout_ms * 1000, false, mem,
1011					op, &status);
1012		if (read_status_ret)
1013			return read_status_ret;
1014	}
1015
1016	return ret;
1017}
1018EXPORT_SYMBOL_GPL(spi_mem_poll_status);
1019
1020static int spi_mem_probe(struct spi_device *spi)
1021{
1022	struct spi_mem_driver *memdrv = to_spi_mem_drv(spi->dev.driver);
1023	struct spi_controller *ctlr = spi->controller;
1024	struct spi_mem *mem;
1025
1026	mem = devm_kzalloc(&spi->dev, sizeof(*mem), GFP_KERNEL);
1027	if (!mem)
1028		return -ENOMEM;
1029
1030	mem->spi = spi;
1031
1032	if (ctlr->mem_ops && ctlr->mem_ops->get_name)
1033		mem->name = ctlr->mem_ops->get_name(mem);
1034	else
1035		mem->name = dev_name(&spi->dev);
1036
1037	if (IS_ERR_OR_NULL(mem->name))
1038		return PTR_ERR_OR_ZERO(mem->name);
1039
1040	spi_set_drvdata(spi, mem);
1041
1042	return memdrv->probe(mem);
1043}
1044
1045static void spi_mem_remove(struct spi_device *spi)
1046{
1047	struct spi_mem_driver *memdrv = to_spi_mem_drv(spi->dev.driver);
1048	struct spi_mem *mem = spi_get_drvdata(spi);
1049
1050	if (memdrv->remove)
1051		memdrv->remove(mem);
1052}
1053
1054static void spi_mem_shutdown(struct spi_device *spi)
1055{
1056	struct spi_mem_driver *memdrv = to_spi_mem_drv(spi->dev.driver);
1057	struct spi_mem *mem = spi_get_drvdata(spi);
1058
1059	if (memdrv->shutdown)
1060		memdrv->shutdown(mem);
1061}
1062
1063/**
1064 * spi_mem_driver_register_with_owner() - Register a SPI memory driver
1065 * @memdrv: the SPI memory driver to register
1066 * @owner: the owner of this driver
1067 *
1068 * Registers a SPI memory driver.
1069 *
1070 * Return: 0 in case of success, a negative error core otherwise.
1071 */
1072
1073int spi_mem_driver_register_with_owner(struct spi_mem_driver *memdrv,
1074				       struct module *owner)
1075{
1076	memdrv->spidrv.probe = spi_mem_probe;
1077	memdrv->spidrv.remove = spi_mem_remove;
1078	memdrv->spidrv.shutdown = spi_mem_shutdown;
1079
1080	return __spi_register_driver(owner, &memdrv->spidrv);
1081}
1082EXPORT_SYMBOL_GPL(spi_mem_driver_register_with_owner);
1083
1084/**
1085 * spi_mem_driver_unregister() - Unregister a SPI memory driver
1086 * @memdrv: the SPI memory driver to unregister
1087 *
1088 * Unregisters a SPI memory driver.
1089 */
1090void spi_mem_driver_unregister(struct spi_mem_driver *memdrv)
1091{
1092	spi_unregister_driver(&memdrv->spidrv);
1093}
1094EXPORT_SYMBOL_GPL(spi_mem_driver_unregister);