xref: /openbmc/linux/drivers/spi/spi-mem.c (revision 9e264f3f)
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 #include "internals.h"
16 
17 #define SPI_MEM_MAX_BUSWIDTH		8
18 
19 /**
20  * spi_controller_dma_map_mem_op_data() - DMA-map the buffer attached to a
21  *					  memory operation
22  * @ctlr: the SPI controller requesting this dma_map()
23  * @op: the memory operation containing the buffer to map
24  * @sgt: a pointer to a non-initialized sg_table that will be filled by this
25  *	 function
26  *
27  * Some controllers might want to do DMA on the data buffer embedded in @op.
28  * This helper prepares everything for you and provides a ready-to-use
29  * sg_table. This function is not intended to be called from spi drivers.
30  * Only SPI controller drivers should use it.
31  * Note that the caller must ensure the memory region pointed by
32  * op->data.buf.{in,out} is DMA-able before calling this function.
33  *
34  * Return: 0 in case of success, a negative error code otherwise.
35  */
spi_controller_dma_map_mem_op_data(struct spi_controller * ctlr,const struct spi_mem_op * op,struct sg_table * sgt)36 int spi_controller_dma_map_mem_op_data(struct spi_controller *ctlr,
37 				       const struct spi_mem_op *op,
38 				       struct sg_table *sgt)
39 {
40 	struct device *dmadev;
41 
42 	if (!op->data.nbytes)
43 		return -EINVAL;
44 
45 	if (op->data.dir == SPI_MEM_DATA_OUT && ctlr->dma_tx)
46 		dmadev = ctlr->dma_tx->device->dev;
47 	else if (op->data.dir == SPI_MEM_DATA_IN && ctlr->dma_rx)
48 		dmadev = ctlr->dma_rx->device->dev;
49 	else
50 		dmadev = ctlr->dev.parent;
51 
52 	if (!dmadev)
53 		return -EINVAL;
54 
55 	return spi_map_buf(ctlr, dmadev, sgt, op->data.buf.in, op->data.nbytes,
56 			   op->data.dir == SPI_MEM_DATA_IN ?
57 			   DMA_FROM_DEVICE : DMA_TO_DEVICE);
58 }
59 EXPORT_SYMBOL_GPL(spi_controller_dma_map_mem_op_data);
60 
61 /**
62  * spi_controller_dma_unmap_mem_op_data() - DMA-unmap the buffer attached to a
63  *					    memory operation
64  * @ctlr: the SPI controller requesting this dma_unmap()
65  * @op: the memory operation containing the buffer to unmap
66  * @sgt: a pointer to an sg_table previously initialized by
67  *	 spi_controller_dma_map_mem_op_data()
68  *
69  * Some controllers might want to do DMA on the data buffer embedded in @op.
70  * This helper prepares things so that the CPU can access the
71  * op->data.buf.{in,out} buffer again.
72  *
73  * This function is not intended to be called from SPI drivers. Only SPI
74  * controller drivers should use it.
75  *
76  * This function should be called after the DMA operation has finished and is
77  * only valid if the previous spi_controller_dma_map_mem_op_data() call
78  * returned 0.
79  *
80  * Return: 0 in case of success, a negative error code otherwise.
81  */
spi_controller_dma_unmap_mem_op_data(struct spi_controller * ctlr,const struct spi_mem_op * op,struct sg_table * sgt)82 void spi_controller_dma_unmap_mem_op_data(struct spi_controller *ctlr,
83 					  const struct spi_mem_op *op,
84 					  struct sg_table *sgt)
85 {
86 	struct device *dmadev;
87 
88 	if (!op->data.nbytes)
89 		return;
90 
91 	if (op->data.dir == SPI_MEM_DATA_OUT && ctlr->dma_tx)
92 		dmadev = ctlr->dma_tx->device->dev;
93 	else if (op->data.dir == SPI_MEM_DATA_IN && ctlr->dma_rx)
94 		dmadev = ctlr->dma_rx->device->dev;
95 	else
96 		dmadev = ctlr->dev.parent;
97 
98 	spi_unmap_buf(ctlr, dmadev, sgt,
99 		      op->data.dir == SPI_MEM_DATA_IN ?
100 		      DMA_FROM_DEVICE : DMA_TO_DEVICE);
101 }
102 EXPORT_SYMBOL_GPL(spi_controller_dma_unmap_mem_op_data);
103 
spi_check_buswidth_req(struct spi_mem * mem,u8 buswidth,bool tx)104 static int spi_check_buswidth_req(struct spi_mem *mem, u8 buswidth, bool tx)
105 {
106 	u32 mode = mem->spi->mode;
107 
108 	switch (buswidth) {
109 	case 1:
110 		return 0;
111 
112 	case 2:
113 		if ((tx &&
114 		     (mode & (SPI_TX_DUAL | SPI_TX_QUAD | SPI_TX_OCTAL))) ||
115 		    (!tx &&
116 		     (mode & (SPI_RX_DUAL | SPI_RX_QUAD | SPI_RX_OCTAL))))
117 			return 0;
118 
119 		break;
120 
121 	case 4:
122 		if ((tx && (mode & (SPI_TX_QUAD | SPI_TX_OCTAL))) ||
123 		    (!tx && (mode & (SPI_RX_QUAD | SPI_RX_OCTAL))))
124 			return 0;
125 
126 		break;
127 
128 	case 8:
129 		if ((tx && (mode & SPI_TX_OCTAL)) ||
130 		    (!tx && (mode & SPI_RX_OCTAL)))
131 			return 0;
132 
133 		break;
134 
135 	default:
136 		break;
137 	}
138 
139 	return -ENOTSUPP;
140 }
141 
spi_mem_check_buswidth(struct spi_mem * mem,const struct spi_mem_op * op)142 static bool spi_mem_check_buswidth(struct spi_mem *mem,
143 				   const struct spi_mem_op *op)
144 {
145 	if (spi_check_buswidth_req(mem, op->cmd.buswidth, true))
146 		return false;
147 
148 	if (op->addr.nbytes &&
149 	    spi_check_buswidth_req(mem, op->addr.buswidth, true))
150 		return false;
151 
152 	if (op->dummy.nbytes &&
153 	    spi_check_buswidth_req(mem, op->dummy.buswidth, true))
154 		return false;
155 
156 	if (op->data.dir != SPI_MEM_NO_DATA &&
157 	    spi_check_buswidth_req(mem, op->data.buswidth,
158 				   op->data.dir == SPI_MEM_DATA_OUT))
159 		return false;
160 
161 	return true;
162 }
163 
spi_mem_default_supports_op(struct spi_mem * mem,const struct spi_mem_op * op)164 bool spi_mem_default_supports_op(struct spi_mem *mem,
165 				 const struct spi_mem_op *op)
166 {
167 	struct spi_controller *ctlr = mem->spi->controller;
168 	bool op_is_dtr =
169 		op->cmd.dtr || op->addr.dtr || op->dummy.dtr || op->data.dtr;
170 
171 	if (op_is_dtr) {
172 		if (!spi_mem_controller_is_capable(ctlr, dtr))
173 			return false;
174 
175 		if (op->cmd.nbytes != 2)
176 			return false;
177 	} else {
178 		if (op->cmd.nbytes != 1)
179 			return false;
180 	}
181 
182 	if (op->data.ecc) {
183 		if (!spi_mem_controller_is_capable(ctlr, ecc))
184 			return false;
185 	}
186 
187 	return spi_mem_check_buswidth(mem, op);
188 }
189 EXPORT_SYMBOL_GPL(spi_mem_default_supports_op);
190 
spi_mem_buswidth_is_valid(u8 buswidth)191 static bool spi_mem_buswidth_is_valid(u8 buswidth)
192 {
193 	if (hweight8(buswidth) > 1 || buswidth > SPI_MEM_MAX_BUSWIDTH)
194 		return false;
195 
196 	return true;
197 }
198 
spi_mem_check_op(const struct spi_mem_op * op)199 static int spi_mem_check_op(const struct spi_mem_op *op)
200 {
201 	if (!op->cmd.buswidth || !op->cmd.nbytes)
202 		return -EINVAL;
203 
204 	if ((op->addr.nbytes && !op->addr.buswidth) ||
205 	    (op->dummy.nbytes && !op->dummy.buswidth) ||
206 	    (op->data.nbytes && !op->data.buswidth))
207 		return -EINVAL;
208 
209 	if (!spi_mem_buswidth_is_valid(op->cmd.buswidth) ||
210 	    !spi_mem_buswidth_is_valid(op->addr.buswidth) ||
211 	    !spi_mem_buswidth_is_valid(op->dummy.buswidth) ||
212 	    !spi_mem_buswidth_is_valid(op->data.buswidth))
213 		return -EINVAL;
214 
215 	/* Buffers must be DMA-able. */
216 	if (WARN_ON_ONCE(op->data.dir == SPI_MEM_DATA_IN &&
217 			 object_is_on_stack(op->data.buf.in)))
218 		return -EINVAL;
219 
220 	if (WARN_ON_ONCE(op->data.dir == SPI_MEM_DATA_OUT &&
221 			 object_is_on_stack(op->data.buf.out)))
222 		return -EINVAL;
223 
224 	return 0;
225 }
226 
spi_mem_internal_supports_op(struct spi_mem * mem,const struct spi_mem_op * op)227 static bool spi_mem_internal_supports_op(struct spi_mem *mem,
228 					 const struct spi_mem_op *op)
229 {
230 	struct spi_controller *ctlr = mem->spi->controller;
231 
232 	if (ctlr->mem_ops && ctlr->mem_ops->supports_op)
233 		return ctlr->mem_ops->supports_op(mem, op);
234 
235 	return spi_mem_default_supports_op(mem, op);
236 }
237 
238 /**
239  * spi_mem_supports_op() - Check if a memory device and the controller it is
240  *			   connected to support a specific memory operation
241  * @mem: the SPI memory
242  * @op: the memory operation to check
243  *
244  * Some controllers are only supporting Single or Dual IOs, others might only
245  * support specific opcodes, or it can even be that the controller and device
246  * both support Quad IOs but the hardware prevents you from using it because
247  * only 2 IO lines are connected.
248  *
249  * This function checks whether a specific operation is supported.
250  *
251  * Return: true if @op is supported, false otherwise.
252  */
spi_mem_supports_op(struct spi_mem * mem,const struct spi_mem_op * op)253 bool spi_mem_supports_op(struct spi_mem *mem, const struct spi_mem_op *op)
254 {
255 	if (spi_mem_check_op(op))
256 		return false;
257 
258 	return spi_mem_internal_supports_op(mem, op);
259 }
260 EXPORT_SYMBOL_GPL(spi_mem_supports_op);
261 
spi_mem_access_start(struct spi_mem * mem)262 static int spi_mem_access_start(struct spi_mem *mem)
263 {
264 	struct spi_controller *ctlr = mem->spi->controller;
265 
266 	/*
267 	 * Flush the message queue before executing our SPI memory
268 	 * operation to prevent preemption of regular SPI transfers.
269 	 */
270 	spi_flush_queue(ctlr);
271 
272 	if (ctlr->auto_runtime_pm) {
273 		int ret;
274 
275 		ret = pm_runtime_resume_and_get(ctlr->dev.parent);
276 		if (ret < 0) {
277 			dev_err(&ctlr->dev, "Failed to power device: %d\n",
278 				ret);
279 			return ret;
280 		}
281 	}
282 
283 	mutex_lock(&ctlr->bus_lock_mutex);
284 	mutex_lock(&ctlr->io_mutex);
285 
286 	return 0;
287 }
288 
spi_mem_access_end(struct spi_mem * mem)289 static void spi_mem_access_end(struct spi_mem *mem)
290 {
291 	struct spi_controller *ctlr = mem->spi->controller;
292 
293 	mutex_unlock(&ctlr->io_mutex);
294 	mutex_unlock(&ctlr->bus_lock_mutex);
295 
296 	if (ctlr->auto_runtime_pm)
297 		pm_runtime_put(ctlr->dev.parent);
298 }
299 
300 /**
301  * spi_mem_exec_op() - Execute a memory operation
302  * @mem: the SPI memory
303  * @op: the memory operation to execute
304  *
305  * Executes a memory operation.
306  *
307  * This function first checks that @op is supported and then tries to execute
308  * it.
309  *
310  * Return: 0 in case of success, a negative error code otherwise.
311  */
spi_mem_exec_op(struct spi_mem * mem,const struct spi_mem_op * op)312 int spi_mem_exec_op(struct spi_mem *mem, const struct spi_mem_op *op)
313 {
314 	unsigned int tmpbufsize, xferpos = 0, totalxferlen = 0;
315 	struct spi_controller *ctlr = mem->spi->controller;
316 	struct spi_transfer xfers[4] = { };
317 	struct spi_message msg;
318 	u8 *tmpbuf;
319 	int ret;
320 
321 	ret = spi_mem_check_op(op);
322 	if (ret)
323 		return ret;
324 
325 	if (!spi_mem_internal_supports_op(mem, op))
326 		return -ENOTSUPP;
327 
328 	if (ctlr->mem_ops && ctlr->mem_ops->exec_op && !spi_get_csgpiod(mem->spi, 0)) {
329 		ret = spi_mem_access_start(mem);
330 		if (ret)
331 			return ret;
332 
333 		ret = ctlr->mem_ops->exec_op(mem, op);
334 
335 		spi_mem_access_end(mem);
336 
337 		/*
338 		 * Some controllers only optimize specific paths (typically the
339 		 * read path) and expect the core to use the regular SPI
340 		 * interface in other cases.
341 		 */
342 		if (!ret || ret != -ENOTSUPP)
343 			return ret;
344 	}
345 
346 	tmpbufsize = op->cmd.nbytes + op->addr.nbytes + op->dummy.nbytes;
347 
348 	/*
349 	 * Allocate a buffer to transmit the CMD, ADDR cycles with kmalloc() so
350 	 * we're guaranteed that this buffer is DMA-able, as required by the
351 	 * SPI layer.
352 	 */
353 	tmpbuf = kzalloc(tmpbufsize, GFP_KERNEL | GFP_DMA);
354 	if (!tmpbuf)
355 		return -ENOMEM;
356 
357 	spi_message_init(&msg);
358 
359 	tmpbuf[0] = op->cmd.opcode;
360 	xfers[xferpos].tx_buf = tmpbuf;
361 	xfers[xferpos].len = op->cmd.nbytes;
362 	xfers[xferpos].tx_nbits = op->cmd.buswidth;
363 	spi_message_add_tail(&xfers[xferpos], &msg);
364 	xferpos++;
365 	totalxferlen++;
366 
367 	if (op->addr.nbytes) {
368 		int i;
369 
370 		for (i = 0; i < op->addr.nbytes; i++)
371 			tmpbuf[i + 1] = op->addr.val >>
372 					(8 * (op->addr.nbytes - i - 1));
373 
374 		xfers[xferpos].tx_buf = tmpbuf + 1;
375 		xfers[xferpos].len = op->addr.nbytes;
376 		xfers[xferpos].tx_nbits = op->addr.buswidth;
377 		spi_message_add_tail(&xfers[xferpos], &msg);
378 		xferpos++;
379 		totalxferlen += op->addr.nbytes;
380 	}
381 
382 	if (op->dummy.nbytes) {
383 		memset(tmpbuf + op->addr.nbytes + 1, 0xff, op->dummy.nbytes);
384 		xfers[xferpos].tx_buf = tmpbuf + op->addr.nbytes + 1;
385 		xfers[xferpos].len = op->dummy.nbytes;
386 		xfers[xferpos].tx_nbits = op->dummy.buswidth;
387 		xfers[xferpos].dummy_data = 1;
388 		spi_message_add_tail(&xfers[xferpos], &msg);
389 		xferpos++;
390 		totalxferlen += op->dummy.nbytes;
391 	}
392 
393 	if (op->data.nbytes) {
394 		if (op->data.dir == SPI_MEM_DATA_IN) {
395 			xfers[xferpos].rx_buf = op->data.buf.in;
396 			xfers[xferpos].rx_nbits = op->data.buswidth;
397 		} else {
398 			xfers[xferpos].tx_buf = op->data.buf.out;
399 			xfers[xferpos].tx_nbits = op->data.buswidth;
400 		}
401 
402 		xfers[xferpos].len = op->data.nbytes;
403 		spi_message_add_tail(&xfers[xferpos], &msg);
404 		xferpos++;
405 		totalxferlen += op->data.nbytes;
406 	}
407 
408 	ret = spi_sync(mem->spi, &msg);
409 
410 	kfree(tmpbuf);
411 
412 	if (ret)
413 		return ret;
414 
415 	if (msg.actual_length != totalxferlen)
416 		return -EIO;
417 
418 	return 0;
419 }
420 EXPORT_SYMBOL_GPL(spi_mem_exec_op);
421 
422 /**
423  * spi_mem_get_name() - Return the SPI mem device name to be used by the
424  *			upper layer if necessary
425  * @mem: the SPI memory
426  *
427  * This function allows SPI mem users to retrieve the SPI mem device name.
428  * It is useful if the upper layer needs to expose a custom name for
429  * compatibility reasons.
430  *
431  * Return: a string containing the name of the memory device to be used
432  *	   by the SPI mem user
433  */
spi_mem_get_name(struct spi_mem * mem)434 const char *spi_mem_get_name(struct spi_mem *mem)
435 {
436 	return mem->name;
437 }
438 EXPORT_SYMBOL_GPL(spi_mem_get_name);
439 
440 /**
441  * spi_mem_adjust_op_size() - Adjust the data size of a SPI mem operation to
442  *			      match controller limitations
443  * @mem: the SPI memory
444  * @op: the operation to adjust
445  *
446  * Some controllers have FIFO limitations and must split a data transfer
447  * operation into multiple ones, others require a specific alignment for
448  * optimized accesses. This function allows SPI mem drivers to split a single
449  * operation into multiple sub-operations when required.
450  *
451  * Return: a negative error code if the controller can't properly adjust @op,
452  *	   0 otherwise. Note that @op->data.nbytes will be updated if @op
453  *	   can't be handled in a single step.
454  */
spi_mem_adjust_op_size(struct spi_mem * mem,struct spi_mem_op * op)455 int spi_mem_adjust_op_size(struct spi_mem *mem, struct spi_mem_op *op)
456 {
457 	struct spi_controller *ctlr = mem->spi->controller;
458 	size_t len;
459 
460 	if (ctlr->mem_ops && ctlr->mem_ops->adjust_op_size)
461 		return ctlr->mem_ops->adjust_op_size(mem, op);
462 
463 	if (!ctlr->mem_ops || !ctlr->mem_ops->exec_op) {
464 		len = op->cmd.nbytes + op->addr.nbytes + op->dummy.nbytes;
465 
466 		if (len > spi_max_transfer_size(mem->spi))
467 			return -EINVAL;
468 
469 		op->data.nbytes = min3((size_t)op->data.nbytes,
470 				       spi_max_transfer_size(mem->spi),
471 				       spi_max_message_size(mem->spi) -
472 				       len);
473 		if (!op->data.nbytes)
474 			return -EINVAL;
475 	}
476 
477 	return 0;
478 }
479 EXPORT_SYMBOL_GPL(spi_mem_adjust_op_size);
480 
spi_mem_no_dirmap_read(struct spi_mem_dirmap_desc * desc,u64 offs,size_t len,void * buf)481 static ssize_t spi_mem_no_dirmap_read(struct spi_mem_dirmap_desc *desc,
482 				      u64 offs, size_t len, void *buf)
483 {
484 	struct spi_mem_op op = desc->info.op_tmpl;
485 	int ret;
486 
487 	op.addr.val = desc->info.offset + offs;
488 	op.data.buf.in = buf;
489 	op.data.nbytes = len;
490 	ret = spi_mem_adjust_op_size(desc->mem, &op);
491 	if (ret)
492 		return ret;
493 
494 	ret = spi_mem_exec_op(desc->mem, &op);
495 	if (ret)
496 		return ret;
497 
498 	return op.data.nbytes;
499 }
500 
spi_mem_no_dirmap_write(struct spi_mem_dirmap_desc * desc,u64 offs,size_t len,const void * buf)501 static ssize_t spi_mem_no_dirmap_write(struct spi_mem_dirmap_desc *desc,
502 				       u64 offs, size_t len, const void *buf)
503 {
504 	struct spi_mem_op op = desc->info.op_tmpl;
505 	int ret;
506 
507 	op.addr.val = desc->info.offset + offs;
508 	op.data.buf.out = buf;
509 	op.data.nbytes = len;
510 	ret = spi_mem_adjust_op_size(desc->mem, &op);
511 	if (ret)
512 		return ret;
513 
514 	ret = spi_mem_exec_op(desc->mem, &op);
515 	if (ret)
516 		return ret;
517 
518 	return op.data.nbytes;
519 }
520 
521 /**
522  * spi_mem_dirmap_create() - Create a direct mapping descriptor
523  * @mem: SPI mem device this direct mapping should be created for
524  * @info: direct mapping information
525  *
526  * This function is creating a direct mapping descriptor which can then be used
527  * to access the memory using spi_mem_dirmap_read() or spi_mem_dirmap_write().
528  * If the SPI controller driver does not support direct mapping, this function
529  * falls back to an implementation using spi_mem_exec_op(), so that the caller
530  * doesn't have to bother implementing a fallback on his own.
531  *
532  * Return: a valid pointer in case of success, and ERR_PTR() otherwise.
533  */
534 struct spi_mem_dirmap_desc *
spi_mem_dirmap_create(struct spi_mem * mem,const struct spi_mem_dirmap_info * info)535 spi_mem_dirmap_create(struct spi_mem *mem,
536 		      const struct spi_mem_dirmap_info *info)
537 {
538 	struct spi_controller *ctlr = mem->spi->controller;
539 	struct spi_mem_dirmap_desc *desc;
540 	int ret = -ENOTSUPP;
541 
542 	/* Make sure the number of address cycles is between 1 and 8 bytes. */
543 	if (!info->op_tmpl.addr.nbytes || info->op_tmpl.addr.nbytes > 8)
544 		return ERR_PTR(-EINVAL);
545 
546 	/* data.dir should either be SPI_MEM_DATA_IN or SPI_MEM_DATA_OUT. */
547 	if (info->op_tmpl.data.dir == SPI_MEM_NO_DATA)
548 		return ERR_PTR(-EINVAL);
549 
550 	desc = kzalloc(sizeof(*desc), GFP_KERNEL);
551 	if (!desc)
552 		return ERR_PTR(-ENOMEM);
553 
554 	desc->mem = mem;
555 	desc->info = *info;
556 	if (ctlr->mem_ops && ctlr->mem_ops->dirmap_create)
557 		ret = ctlr->mem_ops->dirmap_create(desc);
558 
559 	if (ret) {
560 		desc->nodirmap = true;
561 		if (!spi_mem_supports_op(desc->mem, &desc->info.op_tmpl))
562 			ret = -ENOTSUPP;
563 		else
564 			ret = 0;
565 	}
566 
567 	if (ret) {
568 		kfree(desc);
569 		return ERR_PTR(ret);
570 	}
571 
572 	return desc;
573 }
574 EXPORT_SYMBOL_GPL(spi_mem_dirmap_create);
575 
576 /**
577  * spi_mem_dirmap_destroy() - Destroy a direct mapping descriptor
578  * @desc: the direct mapping descriptor to destroy
579  *
580  * This function destroys a direct mapping descriptor previously created by
581  * spi_mem_dirmap_create().
582  */
spi_mem_dirmap_destroy(struct spi_mem_dirmap_desc * desc)583 void spi_mem_dirmap_destroy(struct spi_mem_dirmap_desc *desc)
584 {
585 	struct spi_controller *ctlr = desc->mem->spi->controller;
586 
587 	if (!desc->nodirmap && ctlr->mem_ops && ctlr->mem_ops->dirmap_destroy)
588 		ctlr->mem_ops->dirmap_destroy(desc);
589 
590 	kfree(desc);
591 }
592 EXPORT_SYMBOL_GPL(spi_mem_dirmap_destroy);
593 
devm_spi_mem_dirmap_release(struct device * dev,void * res)594 static void devm_spi_mem_dirmap_release(struct device *dev, void *res)
595 {
596 	struct spi_mem_dirmap_desc *desc = *(struct spi_mem_dirmap_desc **)res;
597 
598 	spi_mem_dirmap_destroy(desc);
599 }
600 
601 /**
602  * devm_spi_mem_dirmap_create() - Create a direct mapping descriptor and attach
603  *				  it to a device
604  * @dev: device the dirmap desc will be attached to
605  * @mem: SPI mem device this direct mapping should be created for
606  * @info: direct mapping information
607  *
608  * devm_ variant of the spi_mem_dirmap_create() function. See
609  * spi_mem_dirmap_create() for more details.
610  *
611  * Return: a valid pointer in case of success, and ERR_PTR() otherwise.
612  */
613 struct spi_mem_dirmap_desc *
devm_spi_mem_dirmap_create(struct device * dev,struct spi_mem * mem,const struct spi_mem_dirmap_info * info)614 devm_spi_mem_dirmap_create(struct device *dev, struct spi_mem *mem,
615 			   const struct spi_mem_dirmap_info *info)
616 {
617 	struct spi_mem_dirmap_desc **ptr, *desc;
618 
619 	ptr = devres_alloc(devm_spi_mem_dirmap_release, sizeof(*ptr),
620 			   GFP_KERNEL);
621 	if (!ptr)
622 		return ERR_PTR(-ENOMEM);
623 
624 	desc = spi_mem_dirmap_create(mem, info);
625 	if (IS_ERR(desc)) {
626 		devres_free(ptr);
627 	} else {
628 		*ptr = desc;
629 		devres_add(dev, ptr);
630 	}
631 
632 	return desc;
633 }
634 EXPORT_SYMBOL_GPL(devm_spi_mem_dirmap_create);
635 
devm_spi_mem_dirmap_match(struct device * dev,void * res,void * data)636 static int devm_spi_mem_dirmap_match(struct device *dev, void *res, void *data)
637 {
638 	struct spi_mem_dirmap_desc **ptr = res;
639 
640 	if (WARN_ON(!ptr || !*ptr))
641 		return 0;
642 
643 	return *ptr == data;
644 }
645 
646 /**
647  * devm_spi_mem_dirmap_destroy() - Destroy a direct mapping descriptor attached
648  *				   to a device
649  * @dev: device the dirmap desc is attached to
650  * @desc: the direct mapping descriptor to destroy
651  *
652  * devm_ variant of the spi_mem_dirmap_destroy() function. See
653  * spi_mem_dirmap_destroy() for more details.
654  */
devm_spi_mem_dirmap_destroy(struct device * dev,struct spi_mem_dirmap_desc * desc)655 void devm_spi_mem_dirmap_destroy(struct device *dev,
656 				 struct spi_mem_dirmap_desc *desc)
657 {
658 	devres_release(dev, devm_spi_mem_dirmap_release,
659 		       devm_spi_mem_dirmap_match, desc);
660 }
661 EXPORT_SYMBOL_GPL(devm_spi_mem_dirmap_destroy);
662 
663 /**
664  * spi_mem_dirmap_read() - Read data through a direct mapping
665  * @desc: direct mapping descriptor
666  * @offs: offset to start reading from. Note that this is not an absolute
667  *	  offset, but the offset within the direct mapping which already has
668  *	  its own offset
669  * @len: length in bytes
670  * @buf: destination buffer. This buffer must be DMA-able
671  *
672  * This function reads data from a memory device using a direct mapping
673  * previously instantiated with spi_mem_dirmap_create().
674  *
675  * Return: the amount of data read from the memory device or a negative error
676  * code. Note that the returned size might be smaller than @len, and the caller
677  * is responsible for calling spi_mem_dirmap_read() again when that happens.
678  */
spi_mem_dirmap_read(struct spi_mem_dirmap_desc * desc,u64 offs,size_t len,void * buf)679 ssize_t spi_mem_dirmap_read(struct spi_mem_dirmap_desc *desc,
680 			    u64 offs, size_t len, void *buf)
681 {
682 	struct spi_controller *ctlr = desc->mem->spi->controller;
683 	ssize_t ret;
684 
685 	if (desc->info.op_tmpl.data.dir != SPI_MEM_DATA_IN)
686 		return -EINVAL;
687 
688 	if (!len)
689 		return 0;
690 
691 	if (desc->nodirmap) {
692 		ret = spi_mem_no_dirmap_read(desc, offs, len, buf);
693 	} else if (ctlr->mem_ops && ctlr->mem_ops->dirmap_read) {
694 		ret = spi_mem_access_start(desc->mem);
695 		if (ret)
696 			return ret;
697 
698 		ret = ctlr->mem_ops->dirmap_read(desc, offs, len, buf);
699 
700 		spi_mem_access_end(desc->mem);
701 	} else {
702 		ret = -ENOTSUPP;
703 	}
704 
705 	return ret;
706 }
707 EXPORT_SYMBOL_GPL(spi_mem_dirmap_read);
708 
709 /**
710  * spi_mem_dirmap_write() - Write data through a direct mapping
711  * @desc: direct mapping descriptor
712  * @offs: offset to start writing from. Note that this is not an absolute
713  *	  offset, but the offset within the direct mapping which already has
714  *	  its own offset
715  * @len: length in bytes
716  * @buf: source buffer. This buffer must be DMA-able
717  *
718  * This function writes data to a memory device using a direct mapping
719  * previously instantiated with spi_mem_dirmap_create().
720  *
721  * Return: the amount of data written to the memory device or a negative error
722  * code. Note that the returned size might be smaller than @len, and the caller
723  * is responsible for calling spi_mem_dirmap_write() again when that happens.
724  */
spi_mem_dirmap_write(struct spi_mem_dirmap_desc * desc,u64 offs,size_t len,const void * buf)725 ssize_t spi_mem_dirmap_write(struct spi_mem_dirmap_desc *desc,
726 			     u64 offs, size_t len, const void *buf)
727 {
728 	struct spi_controller *ctlr = desc->mem->spi->controller;
729 	ssize_t ret;
730 
731 	if (desc->info.op_tmpl.data.dir != SPI_MEM_DATA_OUT)
732 		return -EINVAL;
733 
734 	if (!len)
735 		return 0;
736 
737 	if (desc->nodirmap) {
738 		ret = spi_mem_no_dirmap_write(desc, offs, len, buf);
739 	} else if (ctlr->mem_ops && ctlr->mem_ops->dirmap_write) {
740 		ret = spi_mem_access_start(desc->mem);
741 		if (ret)
742 			return ret;
743 
744 		ret = ctlr->mem_ops->dirmap_write(desc, offs, len, buf);
745 
746 		spi_mem_access_end(desc->mem);
747 	} else {
748 		ret = -ENOTSUPP;
749 	}
750 
751 	return ret;
752 }
753 EXPORT_SYMBOL_GPL(spi_mem_dirmap_write);
754 
to_spi_mem_drv(struct device_driver * drv)755 static inline struct spi_mem_driver *to_spi_mem_drv(struct device_driver *drv)
756 {
757 	return container_of(drv, struct spi_mem_driver, spidrv.driver);
758 }
759 
spi_mem_read_status(struct spi_mem * mem,const struct spi_mem_op * op,u16 * status)760 static int spi_mem_read_status(struct spi_mem *mem,
761 			       const struct spi_mem_op *op,
762 			       u16 *status)
763 {
764 	const u8 *bytes = (u8 *)op->data.buf.in;
765 	int ret;
766 
767 	ret = spi_mem_exec_op(mem, op);
768 	if (ret)
769 		return ret;
770 
771 	if (op->data.nbytes > 1)
772 		*status = ((u16)bytes[0] << 8) | bytes[1];
773 	else
774 		*status = bytes[0];
775 
776 	return 0;
777 }
778 
779 /**
780  * spi_mem_poll_status() - Poll memory device status
781  * @mem: SPI memory device
782  * @op: the memory operation to execute
783  * @mask: status bitmask to ckeck
784  * @match: (status & mask) expected value
785  * @initial_delay_us: delay in us before starting to poll
786  * @polling_delay_us: time to sleep between reads in us
787  * @timeout_ms: timeout in milliseconds
788  *
789  * This function polls a status register and returns when
790  * (status & mask) == match or when the timeout has expired.
791  *
792  * Return: 0 in case of success, -ETIMEDOUT in case of error,
793  *         -EOPNOTSUPP if not supported.
794  */
spi_mem_poll_status(struct spi_mem * mem,const struct spi_mem_op * op,u16 mask,u16 match,unsigned long initial_delay_us,unsigned long polling_delay_us,u16 timeout_ms)795 int spi_mem_poll_status(struct spi_mem *mem,
796 			const struct spi_mem_op *op,
797 			u16 mask, u16 match,
798 			unsigned long initial_delay_us,
799 			unsigned long polling_delay_us,
800 			u16 timeout_ms)
801 {
802 	struct spi_controller *ctlr = mem->spi->controller;
803 	int ret = -EOPNOTSUPP;
804 	int read_status_ret;
805 	u16 status;
806 
807 	if (op->data.nbytes < 1 || op->data.nbytes > 2 ||
808 	    op->data.dir != SPI_MEM_DATA_IN)
809 		return -EINVAL;
810 
811 	if (ctlr->mem_ops && ctlr->mem_ops->poll_status && !spi_get_csgpiod(mem->spi, 0)) {
812 		ret = spi_mem_access_start(mem);
813 		if (ret)
814 			return ret;
815 
816 		ret = ctlr->mem_ops->poll_status(mem, op, mask, match,
817 						 initial_delay_us, polling_delay_us,
818 						 timeout_ms);
819 
820 		spi_mem_access_end(mem);
821 	}
822 
823 	if (ret == -EOPNOTSUPP) {
824 		if (!spi_mem_supports_op(mem, op))
825 			return ret;
826 
827 		if (initial_delay_us < 10)
828 			udelay(initial_delay_us);
829 		else
830 			usleep_range((initial_delay_us >> 2) + 1,
831 				     initial_delay_us);
832 
833 		ret = read_poll_timeout(spi_mem_read_status, read_status_ret,
834 					(read_status_ret || ((status) & mask) == match),
835 					polling_delay_us, timeout_ms * 1000, false, mem,
836 					op, &status);
837 		if (read_status_ret)
838 			return read_status_ret;
839 	}
840 
841 	return ret;
842 }
843 EXPORT_SYMBOL_GPL(spi_mem_poll_status);
844 
spi_mem_probe(struct spi_device * spi)845 static int spi_mem_probe(struct spi_device *spi)
846 {
847 	struct spi_mem_driver *memdrv = to_spi_mem_drv(spi->dev.driver);
848 	struct spi_controller *ctlr = spi->controller;
849 	struct spi_mem *mem;
850 
851 	mem = devm_kzalloc(&spi->dev, sizeof(*mem), GFP_KERNEL);
852 	if (!mem)
853 		return -ENOMEM;
854 
855 	mem->spi = spi;
856 
857 	if (ctlr->mem_ops && ctlr->mem_ops->get_name)
858 		mem->name = ctlr->mem_ops->get_name(mem);
859 	else
860 		mem->name = dev_name(&spi->dev);
861 
862 	if (IS_ERR_OR_NULL(mem->name))
863 		return PTR_ERR_OR_ZERO(mem->name);
864 
865 	spi_set_drvdata(spi, mem);
866 
867 	return memdrv->probe(mem);
868 }
869 
spi_mem_remove(struct spi_device * spi)870 static void spi_mem_remove(struct spi_device *spi)
871 {
872 	struct spi_mem_driver *memdrv = to_spi_mem_drv(spi->dev.driver);
873 	struct spi_mem *mem = spi_get_drvdata(spi);
874 
875 	if (memdrv->remove)
876 		memdrv->remove(mem);
877 }
878 
spi_mem_shutdown(struct spi_device * spi)879 static void spi_mem_shutdown(struct spi_device *spi)
880 {
881 	struct spi_mem_driver *memdrv = to_spi_mem_drv(spi->dev.driver);
882 	struct spi_mem *mem = spi_get_drvdata(spi);
883 
884 	if (memdrv->shutdown)
885 		memdrv->shutdown(mem);
886 }
887 
888 /**
889  * spi_mem_driver_register_with_owner() - Register a SPI memory driver
890  * @memdrv: the SPI memory driver to register
891  * @owner: the owner of this driver
892  *
893  * Registers a SPI memory driver.
894  *
895  * Return: 0 in case of success, a negative error core otherwise.
896  */
897 
spi_mem_driver_register_with_owner(struct spi_mem_driver * memdrv,struct module * owner)898 int spi_mem_driver_register_with_owner(struct spi_mem_driver *memdrv,
899 				       struct module *owner)
900 {
901 	memdrv->spidrv.probe = spi_mem_probe;
902 	memdrv->spidrv.remove = spi_mem_remove;
903 	memdrv->spidrv.shutdown = spi_mem_shutdown;
904 
905 	return __spi_register_driver(owner, &memdrv->spidrv);
906 }
907 EXPORT_SYMBOL_GPL(spi_mem_driver_register_with_owner);
908 
909 /**
910  * spi_mem_driver_unregister() - Unregister a SPI memory driver
911  * @memdrv: the SPI memory driver to unregister
912  *
913  * Unregisters a SPI memory driver.
914  */
spi_mem_driver_unregister(struct spi_mem_driver * memdrv)915 void spi_mem_driver_unregister(struct spi_mem_driver *memdrv)
916 {
917 	spi_unregister_driver(&memdrv->spidrv);
918 }
919 EXPORT_SYMBOL_GPL(spi_mem_driver_unregister);
920