summaryrefslogtreecommitdiff
path: root/drivers/spi/spi-mem.c
blob: e8de4f5017cdc5cb2566a3479970f3d9e5f73c7b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
// SPDX-License-Identifier: GPL-2.0+
/*
 * Copyright (C) 2018 Exceet Electronics GmbH
 * Copyright (C) 2018 Bootlin
 *
 * Author: Boris Brezillon <boris.brezillon@bootlin.com>
 */
#include <linux/dmaengine.h>
#include <linux/iopoll.h>
#include <linux/pm_runtime.h>
#include <linux/spi/spi.h>
#include <linux/spi/spi-mem.h>
#include <linux/sched/task_stack.h>

#include "internals.h"

#define SPI_MEM_MAX_BUSWIDTH		8

/**
 * spi_controller_dma_map_mem_op_data() - DMA-map the buffer attached to a
 *					  memory operation
 * @ctlr: the SPI controller requesting this dma_map()
 * @op: the memory operation containing the buffer to map
 * @sgt: a pointer to a non-initialized sg_table that will be filled by this
 *	 function
 *
 * Some controllers might want to do DMA on the data buffer embedded in @op.
 * This helper prepares everything for you and provides a ready-to-use
 * sg_table. This function is not intended to be called from spi drivers.
 * Only SPI controller drivers should use it.
 * Note that the caller must ensure the memory region pointed by
 * op->data.buf.{in,out} is DMA-able before calling this function.
 *
 * Return: 0 in case of success, a negative error code otherwise.
 */
int spi_controller_dma_map_mem_op_data(struct spi_controller *ctlr,
				       const struct spi_mem_op *op,
				       struct sg_table *sgt)
{
	struct device *dmadev;

	if (!op->data.nbytes)
		return -EINVAL;

	if (op->data.dir == SPI_MEM_DATA_OUT && ctlr->dma_tx)
		dmadev = ctlr->dma_tx->device->dev;
	else if (op->data.dir == SPI_MEM_DATA_IN && ctlr->dma_rx)
		dmadev = ctlr->dma_rx->device->dev;
	else
		dmadev = ctlr->dev.parent;

	if (!dmadev)
		return -EINVAL;

	return spi_map_buf(ctlr, dmadev, sgt, op->data.buf.in, op->data.nbytes,
			   op->data.dir == SPI_MEM_DATA_IN ?
			   DMA_FROM_DEVICE : DMA_TO_DEVICE);
}
EXPORT_SYMBOL_GPL(spi_controller_dma_map_mem_op_data);

/**
 * spi_controller_dma_unmap_mem_op_data() - DMA-unmap the buffer attached to a
 *					    memory operation
 * @ctlr: the SPI controller requesting this dma_unmap()
 * @op: the memory operation containing the buffer to unmap
 * @sgt: a pointer to an sg_table previously initialized by
 *	 spi_controller_dma_map_mem_op_data()
 *
 * Some controllers might want to do DMA on the data buffer embedded in @op.
 * This helper prepares things so that the CPU can access the
 * op->data.buf.{in,out} buffer again.
 *
 * This function is not intended to be called from SPI drivers. Only SPI
 * controller drivers should use it.
 *
 * This function should be called after the DMA operation has finished and is
 * only valid if the previous spi_controller_dma_map_mem_op_data() call
 * returned 0.
 *
 * Return: 0 in case of success, a negative error code otherwise.
 */
void spi_controller_dma_unmap_mem_op_data(struct spi_controller *ctlr,
					  const struct spi_mem_op *op,
					  struct sg_table *sgt)
{
	struct device *dmadev;

	if (!op->data.nbytes)
		return;

	if (op->data.dir == SPI_MEM_DATA_OUT && ctlr->dma_tx)
		dmadev = ctlr->dma_tx->device->dev;
	else if (op->data.dir == SPI_MEM_DATA_IN && ctlr->dma_rx)
		dmadev = ctlr->dma_rx->device->dev;
	else
		dmadev = ctlr->dev.parent;

	spi_unmap_buf(ctlr, dmadev, sgt,
		      op->data.dir == SPI_MEM_DATA_IN ?
		      DMA_FROM_DEVICE : DMA_TO_DEVICE);
}
EXPORT_SYMBOL_GPL(spi_controller_dma_unmap_mem_op_data);

static int spi_check_buswidth_req(struct spi_mem *mem, u8 buswidth, bool tx)
{
	u32 mode = mem->spi->mode;

	switch (buswidth) {
	case 1:
		return 0;

	case 2:
		if ((tx &&
		     (mode & (SPI_TX_DUAL | SPI_TX_QUAD | SPI_TX_OCTAL))) ||
		    (!tx &&
		     (mode & (SPI_RX_DUAL | SPI_RX_QUAD | SPI_RX_OCTAL))))
			return 0;

		break;

	case 4:
		if ((tx && (mode & (SPI_TX_QUAD | SPI_TX_OCTAL))) ||
		    (!tx && (mode & (SPI_RX_QUAD | SPI_RX_OCTAL))))
			return 0;

		break;

	case 8:
		if ((tx && (mode & SPI_TX_OCTAL)) ||
		    (!tx && (mode & SPI_RX_OCTAL)))
			return 0;

		break;

	default:
		break;
	}

	return -ENOTSUPP;
}

static bool spi_mem_check_buswidth(struct spi_mem *mem,
				   const struct spi_mem_op *op)
{
	if (spi_check_buswidth_req(mem, op->cmd.buswidth, true))
		return false;

	if (op->addr.nbytes &&
	    spi_check_buswidth_req(mem, op->addr.buswidth, true))
		return false;

	if (op->dummy.nbytes &&
	    spi_check_buswidth_req(mem, op->dummy.buswidth, true))
		return false;

	if (op->data.dir != SPI_MEM_NO_DATA &&
	    spi_check_buswidth_req(mem, op->data.buswidth,
				   op->data.dir == SPI_MEM_DATA_OUT))
		return false;

	return true;
}

bool spi_mem_default_supports_op(struct spi_mem *mem,
				 const struct spi_mem_op *op)
{
	struct spi_controller *ctlr = mem->spi->controller;
	bool op_is_dtr =
		op->cmd.dtr || op->addr.dtr || op->dummy.dtr || op->data.dtr;

	if (op_is_dtr) {
		if (!spi_mem_controller_is_capable(ctlr, dtr))
			return false;

		if (op->cmd.nbytes != 2)
			return false;
	} else {
		if (op->cmd.nbytes != 1)
			return false;
	}

	if (op->data.ecc) {
		if (!spi_mem_controller_is_capable(ctlr, ecc))
			return false;
	}

	return spi_mem_check_buswidth(mem, op);
}
EXPORT_SYMBOL_GPL(spi_mem_default_supports_op);

static bool spi_mem_buswidth_is_valid(u8 buswidth)
{
	if (hweight8(buswidth) > 1 || buswidth > SPI_MEM_MAX_BUSWIDTH)
		return false;

	return true;
}

static int spi_mem_check_op(const struct spi_mem_op *op)
{
	if (!op->cmd.buswidth || !op->cmd.nbytes)
		return -EINVAL;

	if ((op->addr.nbytes && !op->addr.buswidth) ||
	    (op->dummy.nbytes && !op->dummy.buswidth) ||
	    (op->data.nbytes && !op->data.buswidth))
		return -EINVAL;

	if (!spi_mem_buswidth_is_valid(op->cmd.buswidth) ||
	    !spi_mem_buswidth_is_valid(op->addr.buswidth) ||
	    !spi_mem_buswidth_is_valid(op->dummy.buswidth) ||
	    !spi_mem_buswidth_is_valid(op->data.buswidth))
		return -EINVAL;

	/* Buffers must be DMA-able. */
	if (WARN_ON_ONCE(op->data.dir == SPI_MEM_DATA_IN &&
			 object_is_on_stack(op->data.buf.in)))
		return -EINVAL;

	if (WARN_ON_ONCE(op->data.dir == SPI_MEM_DATA_OUT &&
			 object_is_on_stack(op->data.buf.out)))
		return -EINVAL;

	return 0;
}

static bool spi_mem_internal_supports_op(struct spi_mem *mem,
					 const struct spi_mem_op *op)
{
	struct spi_controller *ctlr = mem->spi->controller;

	if (ctlr->mem_ops && ctlr->mem_ops->supports_op)
		return ctlr->mem_ops->supports_op(mem, op);

	return spi_mem_default_supports_op(mem, op);
}

/**
 * spi_mem_supports_op() - Check if a memory device and the controller it is
 *			   connected to support a specific memory operation
 * @mem: the SPI memory
 * @op: the memory operation to check
 *
 * Some controllers are only supporting Single or Dual IOs, others might only
 * support specific opcodes, or it can even be that the controller and device
 * both support Quad IOs but the hardware prevents you from using it because
 * only 2 IO lines are connected.
 *
 * This function checks whether a specific operation is supported.
 *
 * Return: true if @op is supported, false otherwise.
 */
bool spi_mem_supports_op(struct spi_mem *mem, const struct spi_mem_op *op)
{
	if (spi_mem_check_op(op))
		return false;

	return spi_mem_internal_supports_op(mem, op);
}
EXPORT_SYMBOL_GPL(spi_mem_supports_op);

static int spi_mem_access_start(struct spi_mem *mem)
{
	struct spi_controller *ctlr = mem->spi->controller;

	/*
	 * Flush the message queue before executing our SPI memory
	 * operation to prevent preemption of regular SPI transfers.
	 */
	spi_flush_queue(ctlr);

	if (ctlr->auto_runtime_pm) {
		int ret;

		ret = pm_runtime_resume_and_get(ctlr->dev.parent);
		if (ret < 0) {
			dev_err(&ctlr->dev, "Failed to power device: %d\n",
				ret);
			return ret;
		}
	}

	mutex_lock(&ctlr->bus_lock_mutex);
	mutex_lock(&ctlr->io_mutex);

	return 0;
}

static void spi_mem_access_end(struct spi_mem *mem)
{
	struct spi_controller *ctlr = mem->spi->controller;

	mutex_unlock(&ctlr->io_mutex);
	mutex_unlock(&ctlr->bus_lock_mutex);

	if (ctlr->auto_runtime_pm)
		pm_runtime_put(ctlr->dev.parent);
}

/**
 * spi_mem_exec_op() - Execute a memory operation
 * @mem: the SPI memory
 * @op: the memory operation to execute
 *
 * Executes a memory operation.
 *
 * This function first checks that @op is supported and then tries to execute
 * it.
 *
 * Return: 0 in case of success, a negative error code otherwise.
 */
int spi_mem_exec_op(struct spi_mem *mem, const struct spi_mem_op *op)
{
	unsigned int tmpbufsize, xferpos = 0, totalxferlen = 0;
	struct spi_controller *ctlr = mem->spi->controller;
	struct spi_transfer xfers[4] = { };
	struct spi_message msg;
	u8 *tmpbuf;
	int ret;

	ret = spi_mem_check_op(op);
	if (ret)
		return ret;

	if (!spi_mem_internal_supports_op(mem, op))
		return -ENOTSUPP;

	if (ctlr->mem_ops && !mem->spi->cs_gpiod) {
		ret = spi_mem_access_start(mem);
		if (ret)
			return ret;

		ret = ctlr->mem_ops->exec_op(mem, op);

		spi_mem_access_end(mem);

		/*
		 * Some controllers only optimize specific paths (typically the
		 * read path) and expect the core to use the regular SPI
		 * interface in other cases.
		 */
		if (!ret || ret != -ENOTSUPP)
			return ret;
	}

	tmpbufsize = op->cmd.nbytes + op->addr.nbytes + op->dummy.nbytes;

	/*
	 * Allocate a buffer to transmit the CMD, ADDR cycles with kmalloc() so
	 * we're guaranteed that this buffer is DMA-able, as required by the
	 * SPI layer.
	 */
	tmpbuf = kzalloc(tmpbufsize, GFP_KERNEL | GFP_DMA);
	if (!tmpbuf)
		return -ENOMEM;

	spi_message_init(&msg);

	tmpbuf[0] = op->cmd.opcode;
	xfers[xferpos].tx_buf = tmpbuf;
	xfers[xferpos].len = op->cmd.nbytes;
	xfers[xferpos].tx_nbits = op->cmd.buswidth;
	spi_message_add_tail(&xfers[xferpos], &msg);
	xferpos++;
	totalxferlen++;

	if (op->addr.nbytes) {
		int i;

		for (i = 0; i < op->addr.nbytes; i++)
			tmpbuf[i + 1] = op->addr.val >>
					(8 * (op->addr.nbytes - i - 1));

		xfers[xferpos].tx_buf = tmpbuf + 1;
		xfers[xferpos].len = op->addr.nbytes;
		xfers[xferpos].tx_nbits = op->addr.buswidth;
		spi_message_add_tail(&xfers[xferpos], &msg);
		xferpos++;
		totalxferlen += op->addr.nbytes;
	}

	if (op->dummy.nbytes) {
		memset(tmpbuf + op->addr.nbytes + 1, 0xff, op->dummy.nbytes);
		xfers[xferpos].tx_buf = tmpbuf + op->addr.nbytes + 1;
		xfers[xferpos].len = op->dummy.nbytes;
		xfers[xferpos].tx_nbits = op->dummy.buswidth;
		xfers[xferpos].dummy_data = 1;
		spi_message_add_tail(&xfers[xferpos], &msg);
		xferpos++;
		totalxferlen += op->dummy.nbytes;
	}

	if (op->data.nbytes) {
		if (op->data.dir == SPI_MEM_DATA_IN) {
			xfers[xferpos].rx_buf = op->data.buf.in;
			xfers[xferpos].rx_nbits = op->data.buswidth;
		} else {
			xfers[xferpos].tx_buf = op->data.buf.out;
			xfers[xferpos].tx_nbits = op->data.buswidth;
		}

		xfers[xferpos].len = op->data.nbytes;
		spi_message_add_tail(&xfers[xferpos], &msg);
		xferpos++;
		totalxferlen += op->data.nbytes;
	}

	ret = spi_sync(mem->spi, &msg);

	kfree(tmpbuf);

	if (ret)
		return ret;

	if (msg.actual_length != totalxferlen)
		return -EIO;

	return 0;
}
EXPORT_SYMBOL_GPL(spi_mem_exec_op);

/**
 * spi_mem_get_name() - Return the SPI mem device name to be used by the
 *			upper layer if necessary
 * @mem: the SPI memory
 *
 * This function allows SPI mem users to retrieve the SPI mem device name.
 * It is useful if the upper layer needs to expose a custom name for
 * compatibility reasons.
 *
 * Return: a string containing the name of the memory device to be used
 *	   by the SPI mem user
 */
const char *spi_mem_get_name(struct spi_mem *mem)
{
	return mem->name;
}
EXPORT_SYMBOL_GPL(spi_mem_get_name);

/**
 * spi_mem_adjust_op_size() - Adjust the data size of a SPI mem operation to
 *			      match controller limitations
 * @mem: the SPI memory
 * @op: the operation to adjust
 *
 * Some controllers have FIFO limitations and must split a data transfer
 * operation into multiple ones, others require a specific alignment for
 * optimized accesses. This function allows SPI mem drivers to split a single
 * operation into multiple sub-operations when required.
 *
 * Return: a negative error code if the controller can't properly adjust @op,
 *	   0 otherwise. Note that @op->data.nbytes will be updated if @op
 *	   can't be handled in a single step.
 */
int spi_mem_adjust_op_size(struct spi_mem *mem, struct spi_mem_op *op)
{
	struct spi_controller *ctlr = mem->spi->controller;
	size_t len;

	if (ctlr->mem_ops && ctlr->mem_ops->adjust_op_size)
		return ctlr->mem_ops->adjust_op_size(mem, op);

	if (!ctlr->mem_ops || !ctlr->mem_ops->exec_op) {
		len = op->cmd.nbytes + op->addr.nbytes + op->dummy.nbytes;

		if (len > spi_max_transfer_size(mem->spi))
			return -EINVAL;

		op->data.nbytes = min3((size_t)op->data.nbytes,
				       spi_max_transfer_size(mem->spi),
				       spi_max_message_size(mem->spi) -
				       len);
		if (!op->data.nbytes)
			return -EINVAL;
	}

	return 0;
}
EXPORT_SYMBOL_GPL(spi_mem_adjust_op_size);

static ssize_t spi_mem_no_dirmap_read(struct spi_mem_dirmap_desc *desc,
				      u64 offs, size_t len, void *buf)
{
	struct spi_mem_op op = desc->info.op_tmpl;
	int ret;

	op.addr.val = desc->info.offset + offs;
	op.data.buf.in = buf;
	op.data.nbytes = len;
	ret = spi_mem_adjust_op_size(desc->mem, &op);
	if (ret)
		return ret;

	ret = spi_mem_exec_op(desc->mem, &op);
	if (ret)
		return ret;

	return op.data.nbytes;
}

static ssize_t spi_mem_no_dirmap_write(struct spi_mem_dirmap_desc *desc,
				       u64 offs, size_t len, const void *buf)
{
	struct spi_mem_op op = desc->info.op_tmpl;
	int ret;

	op.addr.val = desc->info.offset + offs;
	op.data.buf.out = buf;
	op.data.nbytes = len;
	ret = spi_mem_adjust_op_size(desc->mem, &op);
	if (ret)
		return ret;

	ret = spi_mem_exec_op(desc->mem, &op);
	if (ret)
		return ret;

	return op.data.nbytes;
}

/**
 * spi_mem_dirmap_create() - Create a direct mapping descriptor
 * @mem: SPI mem device this direct mapping should be created for
 * @info: direct mapping information
 *
 * This function is creating a direct mapping descriptor which can then be used
 * to access the memory using spi_mem_dirmap_read() or spi_mem_dirmap_write().
 * If the SPI controller driver does not support direct mapping, this function
 * falls back to an implementation using spi_mem_exec_op(), so that the caller
 * doesn't have to bother implementing a fallback on his own.
 *
 * Return: a valid pointer in case of success, and ERR_PTR() otherwise.
 */
struct spi_mem_dirmap_desc *
spi_mem_dirmap_create(struct spi_mem *mem,
		      const struct spi_mem_dirmap_info *info)
{
	struct spi_controller *ctlr = mem->spi->controller;
	struct spi_mem_dirmap_desc *desc;
	int ret = -ENOTSUPP;

	/* Make sure the number of address cycles is between 1 and 8 bytes. */
	if (!info->op_tmpl.addr.nbytes || info->op_tmpl.addr.nbytes > 8)
		return ERR_PTR(-EINVAL);

	/* data.dir should either be SPI_MEM_DATA_IN or SPI_MEM_DATA_OUT. */
	if (info->op_tmpl.data.dir == SPI_MEM_NO_DATA)
		return ERR_PTR(-EINVAL);

	desc = kzalloc(sizeof(*desc), GFP_KERNEL);
	if (!desc)
		return ERR_PTR(-ENOMEM);

	desc->mem = mem;
	desc->info = *info;
	if (ctlr->mem_ops && ctlr->mem_ops->dirmap_create)
		ret = ctlr->mem_ops->dirmap_create(desc);

	if (ret) {
		desc->nodirmap = true;
		if (!spi_mem_supports_op(desc->mem, &desc->info.op_tmpl))
			ret = -ENOTSUPP;
		else
			ret = 0;
	}

	if (ret) {
		kfree(desc);
		return ERR_PTR(ret);
	}

	return desc;
}
EXPORT_SYMBOL_GPL(spi_mem_dirmap_create);

/**
 * spi_mem_dirmap_destroy() - Destroy a direct mapping descriptor
 * @desc: the direct mapping descriptor to destroy
 *
 * This function destroys a direct mapping descriptor previously created by
 * spi_mem_dirmap_create().
 */
void spi_mem_dirmap_destroy(struct spi_mem_dirmap_desc *desc)
{
	struct spi_controller *ctlr = desc->mem->spi->controller;

	if (!desc->nodirmap && ctlr->mem_ops && ctlr->mem_ops->dirmap_destroy)
		ctlr->mem_ops->dirmap_destroy(desc);

	kfree(desc);
}
EXPORT_SYMBOL_GPL(spi_mem_dirmap_destroy);

static void devm_spi_mem_dirmap_release(struct device *dev, void *res)
{
	struct spi_mem_dirmap_desc *desc = *(struct spi_mem_dirmap_desc **)res;

	spi_mem_dirmap_destroy(desc);
}

/**
 * devm_spi_mem_dirmap_create() - Create a direct mapping descriptor and attach
 *				  it to a device
 * @dev: device the dirmap desc will be attached to
 * @mem: SPI mem device this direct mapping should be created for
 * @info: direct mapping information
 *
 * devm_ variant of the spi_mem_dirmap_create() function. See
 * spi_mem_dirmap_create() for more details.
 *
 * Return: a valid pointer in case of success, and ERR_PTR() otherwise.
 */
struct spi_mem_dirmap_desc *
devm_spi_mem_dirmap_create(struct device *dev, struct spi_mem *mem,
			   const struct spi_mem_dirmap_info *info)
{
	struct spi_mem_dirmap_desc **ptr, *desc;

	ptr = devres_alloc(devm_spi_mem_dirmap_release, sizeof(*ptr),
			   GFP_KERNEL);
	if (!ptr)
		return ERR_PTR(-ENOMEM);

	desc = spi_mem_dirmap_create(mem, info);
	if (IS_ERR(desc)) {
		devres_free(ptr);
	} else {
		*ptr = desc;
		devres_add(dev, ptr);
	}

	return desc;
}
EXPORT_SYMBOL_GPL(devm_spi_mem_dirmap_create);

static int devm_spi_mem_dirmap_match(struct device *dev, void *res, void *data)
{
	struct spi_mem_dirmap_desc **ptr = res;

	if (WARN_ON(!ptr || !*ptr))
		return 0;

	return *ptr == data;
}

/**
 * devm_spi_mem_dirmap_destroy() - Destroy a direct mapping descriptor attached
 *				   to a device
 * @dev: device the dirmap desc is attached to
 * @desc: the direct mapping descriptor to destroy
 *
 * devm_ variant of the spi_mem_dirmap_destroy() function. See
 * spi_mem_dirmap_destroy() for more details.
 */
void devm_spi_mem_dirmap_destroy(struct device *dev,
				 struct spi_mem_dirmap_desc *desc)
{
	devres_release(dev, devm_spi_mem_dirmap_release,
		       devm_spi_mem_dirmap_match, desc);
}
EXPORT_SYMBOL_GPL(devm_spi_mem_dirmap_destroy);

/**
 * spi_mem_dirmap_read() - Read data through a direct mapping
 * @desc: direct mapping descriptor
 * @offs: offset to start reading from. Note that this is not an absolute
 *	  offset, but the offset within the direct mapping which already has
 *	  its own offset
 * @len: length in bytes
 * @buf: destination buffer. This buffer must be DMA-able
 *
 * This function reads data from a memory device using a direct mapping
 * previously instantiated with spi_mem_dirmap_create().
 *
 * Return: the amount of data read from the memory device or a negative error
 * code. Note that the returned size might be smaller than @len, and the caller
 * is responsible for calling spi_mem_dirmap_read() again when that happens.
 */
ssize_t spi_mem_dirmap_read(struct spi_mem_dirmap_desc *desc,
			    u64 offs, size_t len, void *buf)
{
	struct spi_controller *ctlr = desc->mem->spi->controller;
	ssize_t ret;

	if (desc->info.op_tmpl.data.dir != SPI_MEM_DATA_IN)
		return -EINVAL;

	if (!len)
		return 0;

	if (desc->nodirmap) {
		ret = spi_mem_no_dirmap_read(desc, offs, len, buf);
	} else if (ctlr->mem_ops && ctlr->mem_ops->dirmap_read) {
		ret = spi_mem_access_start(desc->mem);
		if (ret)
			return ret;

		ret = ctlr->mem_ops->dirmap_read(desc, offs, len, buf);

		spi_mem_access_end(desc->mem);
	} else {
		ret = -ENOTSUPP;
	}

	return ret;
}
EXPORT_SYMBOL_GPL(spi_mem_dirmap_read);

/**
 * spi_mem_dirmap_write() - Write data through a direct mapping
 * @desc: direct mapping descriptor
 * @offs: offset to start writing from. Note that this is not an absolute
 *	  offset, but the offset within the direct mapping which already has
 *	  its own offset
 * @len: length in bytes
 * @buf: source buffer. This buffer must be DMA-able
 *
 * This function writes data to a memory device using a direct mapping
 * previously instantiated with spi_mem_dirmap_create().
 *
 * Return: the amount of data written to the memory device or a negative error
 * code. Note that the returned size might be smaller than @len, and the caller
 * is responsible for calling spi_mem_dirmap_write() again when that happens.
 */
ssize_t spi_mem_dirmap_write(struct spi_mem_dirmap_desc *desc,
			     u64 offs, size_t len, const void *buf)
{
	struct spi_controller *ctlr = desc->mem->spi->controller;
	ssize_t ret;

	if (desc->info.op_tmpl.data.dir != SPI_MEM_DATA_OUT)
		return -EINVAL;

	if (!len)
		return 0;

	if (desc->nodirmap) {
		ret = spi_mem_no_dirmap_write(desc, offs, len, buf);
	} else if (ctlr->mem_ops && ctlr->mem_ops->dirmap_write) {
		ret = spi_mem_access_start(desc->mem);
		if (ret)
			return ret;

		ret = ctlr->mem_ops->dirmap_write(desc, offs, len, buf);

		spi_mem_access_end(desc->mem);
	} else {
		ret = -ENOTSUPP;
	}

	return ret;
}
EXPORT_SYMBOL_GPL(spi_mem_dirmap_write);

static inline struct spi_mem_driver *to_spi_mem_drv(struct device_driver *drv)
{
	return container_of(drv, struct spi_mem_driver, spidrv.driver);
}

static int spi_mem_read_status(struct spi_mem *mem,
			       const struct spi_mem_op *op,
			       u16 *status)
{
	const u8 *bytes = (u8 *)op->data.buf.in;
	int ret;

	ret = spi_mem_exec_op(mem, op);
	if (ret)
		return ret;

	if (op->data.nbytes > 1)
		*status = ((u16)bytes[0] << 8) | bytes[1];
	else
		*status = bytes[0];

	return 0;
}

/**
 * spi_mem_poll_status() - Poll memory device status
 * @mem: SPI memory device
 * @op: the memory operation to execute
 * @mask: status bitmask to ckeck
 * @match: (status & mask) expected value
 * @initial_delay_us: delay in us before starting to poll
 * @polling_delay_us: time to sleep between reads in us
 * @timeout_ms: timeout in milliseconds
 *
 * This function polls a status register and returns when
 * (status & mask) == match or when the timeout has expired.
 *
 * Return: 0 in case of success, -ETIMEDOUT in case of error,
 *         -EOPNOTSUPP if not supported.
 */
int 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)
{
	struct spi_controller *ctlr = mem->spi->controller;
	int ret = -EOPNOTSUPP;
	int read_status_ret;
	u16 status;

	if (op->data.nbytes < 1 || op->data.nbytes > 2 ||
	    op->data.dir != SPI_MEM_DATA_IN)
		return -EINVAL;

	if (ctlr->mem_ops && ctlr->mem_ops->poll_status) {
		ret = spi_mem_access_start(mem);
		if (ret)
			return ret;

		ret = ctlr->mem_ops->poll_status(mem, op, mask, match,
						 initial_delay_us, polling_delay_us,
						 timeout_ms);

		spi_mem_access_end(mem);
	}

	if (ret == -EOPNOTSUPP) {
		if (!spi_mem_supports_op(mem, op))
			return ret;

		if (initial_delay_us < 10)
			udelay(initial_delay_us);
		else
			usleep_range((initial_delay_us >> 2) + 1,
				     initial_delay_us);

		ret = read_poll_timeout(spi_mem_read_status, read_status_ret,
					(read_status_ret || ((status) & mask) == match),
					polling_delay_us, timeout_ms * 1000, false, mem,
					op, &status);
		if (read_status_ret)
			return read_status_ret;
	}

	return ret;
}
EXPORT_SYMBOL_GPL(spi_mem_poll_status);

static int spi_mem_probe(struct spi_device *spi)
{
	struct spi_mem_driver *memdrv = to_spi_mem_drv(spi->dev.driver);
	struct spi_controller *ctlr = spi->controller;
	struct spi_mem *mem;

	mem = devm_kzalloc(&spi->dev, sizeof(*mem), GFP_KERNEL);
	if (!mem)
		return -ENOMEM;

	mem->spi = spi;

	if (ctlr->mem_ops && ctlr->mem_ops->get_name)
		mem->name = ctlr->mem_ops->get_name(mem);
	else
		mem->name = dev_name(&spi->dev);

	if (IS_ERR_OR_NULL(mem->name))
		return PTR_ERR_OR_ZERO(mem->name);

	spi_set_drvdata(spi, mem);

	return memdrv->probe(mem);
}

static void spi_mem_remove(struct spi_device *spi)
{
	struct spi_mem_driver *memdrv = to_spi_mem_drv(spi->dev.driver);
	struct spi_mem *mem = spi_get_drvdata(spi);

	if (memdrv->remove)
		memdrv->remove(mem);
}

static void spi_mem_shutdown(struct spi_device *spi)
{
	struct spi_mem_driver *memdrv = to_spi_mem_drv(spi->dev.driver);
	struct spi_mem *mem = spi_get_drvdata(spi);

	if (memdrv->shutdown)
		memdrv->shutdown(mem);
}

/**
 * spi_mem_driver_register_with_owner() - Register a SPI memory driver
 * @memdrv: the SPI memory driver to register
 * @owner: the owner of this driver
 *
 * Registers a SPI memory driver.
 *
 * Return: 0 in case of success, a negative error core otherwise.
 */

int spi_mem_driver_register_with_owner(struct spi_mem_driver *memdrv,
				       struct module *owner)
{
	memdrv->spidrv.probe = spi_mem_probe;
	memdrv->spidrv.remove = spi_mem_remove;
	memdrv->spidrv.shutdown = spi_mem_shutdown;

	return __spi_register_driver(owner, &memdrv->spidrv);
}
EXPORT_SYMBOL_GPL(spi_mem_driver_register_with_owner);

/**
 * spi_mem_driver_unregister() - Unregister a SPI memory driver
 * @memdrv: the SPI memory driver to unregister
 *
 * Unregisters a SPI memory driver.
 */
void spi_mem_driver_unregister(struct spi_mem_driver *memdrv)
{
	spi_unregister_driver(&memdrv->spidrv);
}
EXPORT_SYMBOL_GPL(spi_mem_driver_unregister);