aboutsummaryrefslogtreecommitdiff
path: root/drivers/spi/spi-geni-qcom.c
blob: 3d0d8ddd5772089051257060274b25b282fe55e0 (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
// SPDX-License-Identifier: GPL-2.0
// Copyright (c) 2017-2018, The Linux foundation. All rights reserved.

#include <linux/clk.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/log2.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/pm_opp.h>
#include <linux/pm_runtime.h>
#include <linux/qcom-geni-se.h>
#include <linux/spi/spi.h>
#include <linux/spinlock.h>

/* SPI SE specific registers and respective register fields */
#define SE_SPI_CPHA		0x224
#define CPHA			BIT(0)

#define SE_SPI_LOOPBACK		0x22c
#define LOOPBACK_ENABLE		0x1
#define NORMAL_MODE		0x0
#define LOOPBACK_MSK		GENMASK(1, 0)

#define SE_SPI_CPOL		0x230
#define CPOL			BIT(2)

#define SE_SPI_DEMUX_OUTPUT_INV	0x24c
#define CS_DEMUX_OUTPUT_INV_MSK	GENMASK(3, 0)

#define SE_SPI_DEMUX_SEL	0x250
#define CS_DEMUX_OUTPUT_SEL	GENMASK(3, 0)

#define SE_SPI_TRANS_CFG	0x25c
#define CS_TOGGLE		BIT(0)

#define SE_SPI_WORD_LEN		0x268
#define WORD_LEN_MSK		GENMASK(9, 0)
#define MIN_WORD_LEN		4

#define SE_SPI_TX_TRANS_LEN	0x26c
#define SE_SPI_RX_TRANS_LEN	0x270
#define TRANS_LEN_MSK		GENMASK(23, 0)

#define SE_SPI_PRE_POST_CMD_DLY	0x274

#define SE_SPI_DELAY_COUNTERS	0x278
#define SPI_INTER_WORDS_DELAY_MSK	GENMASK(9, 0)
#define SPI_CS_CLK_DELAY_MSK		GENMASK(19, 10)
#define SPI_CS_CLK_DELAY_SHFT		10

/* M_CMD OP codes for SPI */
#define SPI_TX_ONLY		1
#define SPI_RX_ONLY		2
#define SPI_TX_RX		7
#define SPI_CS_ASSERT		8
#define SPI_CS_DEASSERT		9
#define SPI_SCK_ONLY		10
/* M_CMD params for SPI */
#define SPI_PRE_CMD_DELAY	BIT(0)
#define TIMESTAMP_BEFORE	BIT(1)
#define FRAGMENTATION		BIT(2)
#define TIMESTAMP_AFTER		BIT(3)
#define POST_CMD_DELAY		BIT(4)

struct spi_geni_master {
	struct geni_se se;
	struct device *dev;
	u32 tx_fifo_depth;
	u32 fifo_width_bits;
	u32 tx_wm;
	u32 last_mode;
	unsigned long cur_speed_hz;
	unsigned long cur_sclk_hz;
	unsigned int cur_bits_per_word;
	unsigned int tx_rem_bytes;
	unsigned int rx_rem_bytes;
	const struct spi_transfer *cur_xfer;
	struct completion cs_done;
	struct completion cancel_done;
	struct completion abort_done;
	unsigned int oversampling;
	spinlock_t lock;
	int irq;
	bool cs_flag;
	bool abort_failed;
};

static int get_spi_clk_cfg(unsigned int speed_hz,
			struct spi_geni_master *mas,
			unsigned int *clk_idx,
			unsigned int *clk_div)
{
	unsigned long sclk_freq;
	unsigned int actual_hz;
	int ret;

	ret = geni_se_clk_freq_match(&mas->se,
				speed_hz * mas->oversampling,
				clk_idx, &sclk_freq, false);
	if (ret) {
		dev_err(mas->dev, "Failed(%d) to find src clk for %dHz\n",
							ret, speed_hz);
		return ret;
	}

	*clk_div = DIV_ROUND_UP(sclk_freq, mas->oversampling * speed_hz);
	actual_hz = sclk_freq / (mas->oversampling * *clk_div);

	dev_dbg(mas->dev, "req %u=>%u sclk %lu, idx %d, div %d\n", speed_hz,
				actual_hz, sclk_freq, *clk_idx, *clk_div);
	ret = dev_pm_opp_set_rate(mas->dev, sclk_freq);
	if (ret)
		dev_err(mas->dev, "dev_pm_opp_set_rate failed %d\n", ret);
	else
		mas->cur_sclk_hz = sclk_freq;

	return ret;
}

static void handle_fifo_timeout(struct spi_master *spi,
				struct spi_message *msg)
{
	struct spi_geni_master *mas = spi_master_get_devdata(spi);
	unsigned long time_left;
	struct geni_se *se = &mas->se;

	spin_lock_irq(&mas->lock);
	reinit_completion(&mas->cancel_done);
	writel(0, se->base + SE_GENI_TX_WATERMARK_REG);
	mas->cur_xfer = NULL;
	geni_se_cancel_m_cmd(se);
	spin_unlock_irq(&mas->lock);

	time_left = wait_for_completion_timeout(&mas->cancel_done, HZ);
	if (time_left)
		return;

	spin_lock_irq(&mas->lock);
	reinit_completion(&mas->abort_done);
	geni_se_abort_m_cmd(se);
	spin_unlock_irq(&mas->lock);

	time_left = wait_for_completion_timeout(&mas->abort_done, HZ);
	if (!time_left) {
		dev_err(mas->dev, "Failed to cancel/abort m_cmd\n");

		/*
		 * No need for a lock since SPI core has a lock and we never
		 * access this from an interrupt.
		 */
		mas->abort_failed = true;
	}
}

static bool spi_geni_is_abort_still_pending(struct spi_geni_master *mas)
{
	struct geni_se *se = &mas->se;
	u32 m_irq, m_irq_en;

	if (!mas->abort_failed)
		return false;

	/*
	 * The only known case where a transfer times out and then a cancel
	 * times out then an abort times out is if something is blocking our
	 * interrupt handler from running.  Avoid starting any new transfers
	 * until that sorts itself out.
	 */
	spin_lock_irq(&mas->lock);
	m_irq = readl(se->base + SE_GENI_M_IRQ_STATUS);
	m_irq_en = readl(se->base + SE_GENI_M_IRQ_EN);
	spin_unlock_irq(&mas->lock);

	if (m_irq & m_irq_en) {
		dev_err(mas->dev, "Interrupts pending after abort: %#010x\n",
			m_irq & m_irq_en);
		return true;
	}

	/*
	 * If we're here the problem resolved itself so no need to check more
	 * on future transfers.
	 */
	mas->abort_failed = false;

	return false;
}

static void spi_geni_set_cs(struct spi_device *slv, bool set_flag)
{
	struct spi_geni_master *mas = spi_master_get_devdata(slv->master);
	struct spi_master *spi = dev_get_drvdata(mas->dev);
	struct geni_se *se = &mas->se;
	unsigned long time_left;

	if (!(slv->mode & SPI_CS_HIGH))
		set_flag = !set_flag;

	if (set_flag == mas->cs_flag)
		return;

	pm_runtime_get_sync(mas->dev);

	if (spi_geni_is_abort_still_pending(mas)) {
		dev_err(mas->dev, "Can't set chip select\n");
		goto exit;
	}

	spin_lock_irq(&mas->lock);
	if (mas->cur_xfer) {
		dev_err(mas->dev, "Can't set CS when prev xfer running\n");
		spin_unlock_irq(&mas->lock);
		goto exit;
	}

	mas->cs_flag = set_flag;
	reinit_completion(&mas->cs_done);
	if (set_flag)
		geni_se_setup_m_cmd(se, SPI_CS_ASSERT, 0);
	else
		geni_se_setup_m_cmd(se, SPI_CS_DEASSERT, 0);
	spin_unlock_irq(&mas->lock);

	time_left = wait_for_completion_timeout(&mas->cs_done, HZ);
	if (!time_left) {
		dev_warn(mas->dev, "Timeout setting chip select\n");
		handle_fifo_timeout(spi, NULL);
	}

exit:
	pm_runtime_put(mas->dev);
}

static void spi_setup_word_len(struct spi_geni_master *mas, u16 mode,
					unsigned int bits_per_word)
{
	unsigned int pack_words;
	bool msb_first = (mode & SPI_LSB_FIRST) ? false : true;
	struct geni_se *se = &mas->se;
	u32 word_len;

	/*
	 * If bits_per_word isn't a byte aligned value, set the packing to be
	 * 1 SPI word per FIFO word.
	 */
	if (!(mas->fifo_width_bits % bits_per_word))
		pack_words = mas->fifo_width_bits / bits_per_word;
	else
		pack_words = 1;
	geni_se_config_packing(&mas->se, bits_per_word, pack_words, msb_first,
								true, true);
	word_len = (bits_per_word - MIN_WORD_LEN) & WORD_LEN_MSK;
	writel(word_len, se->base + SE_SPI_WORD_LEN);
}

static int geni_spi_set_clock_and_bw(struct spi_geni_master *mas,
					unsigned long clk_hz)
{
	u32 clk_sel, m_clk_cfg, idx, div;
	struct geni_se *se = &mas->se;
	int ret;

	if (clk_hz == mas->cur_speed_hz)
		return 0;

	ret = get_spi_clk_cfg(clk_hz, mas, &idx, &div);
	if (ret) {
		dev_err(mas->dev, "Err setting clk to %lu: %d\n", clk_hz, ret);
		return ret;
	}

	/*
	 * SPI core clock gets configured with the requested frequency
	 * or the frequency closer to the requested frequency.
	 * For that reason requested frequency is stored in the
	 * cur_speed_hz and referred in the consecutive transfer instead
	 * of calling clk_get_rate() API.
	 */
	mas->cur_speed_hz = clk_hz;

	clk_sel = idx & CLK_SEL_MSK;
	m_clk_cfg = (div << CLK_DIV_SHFT) | SER_CLK_EN;
	writel(clk_sel, se->base + SE_GENI_CLK_SEL);
	writel(m_clk_cfg, se->base + GENI_SER_M_CLK_CFG);

	/* Set BW quota for CPU as driver supports FIFO mode only. */
	se->icc_paths[CPU_TO_GENI].avg_bw = Bps_to_icc(mas->cur_speed_hz);
	ret = geni_icc_set_bw(se);
	if (ret)
		return ret;

	return 0;
}

static int setup_fifo_params(struct spi_device *spi_slv,
					struct spi_master *spi)
{
	struct spi_geni_master *mas = spi_master_get_devdata(spi);
	struct geni_se *se = &mas->se;
	u32 loopback_cfg = 0, cpol = 0, cpha = 0, demux_output_inv = 0;
	u32 demux_sel;

	if (mas->last_mode != spi_slv->mode) {
		if (spi_slv->mode & SPI_LOOP)
			loopback_cfg = LOOPBACK_ENABLE;

		if (spi_slv->mode & SPI_CPOL)
			cpol = CPOL;

		if (spi_slv->mode & SPI_CPHA)
			cpha = CPHA;

		if (spi_slv->mode & SPI_CS_HIGH)
			demux_output_inv = BIT(spi_slv->chip_select);

		demux_sel = spi_slv->chip_select;
		mas->cur_bits_per_word = spi_slv->bits_per_word;

		spi_setup_word_len(mas, spi_slv->mode, spi_slv->bits_per_word);
		writel(loopback_cfg, se->base + SE_SPI_LOOPBACK);
		writel(demux_sel, se->base + SE_SPI_DEMUX_SEL);
		writel(cpha, se->base + SE_SPI_CPHA);
		writel(cpol, se->base + SE_SPI_CPOL);
		writel(demux_output_inv, se->base + SE_SPI_DEMUX_OUTPUT_INV);

		mas->last_mode = spi_slv->mode;
	}

	return geni_spi_set_clock_and_bw(mas, spi_slv->max_speed_hz);
}

static int spi_geni_prepare_message(struct spi_master *spi,
					struct spi_message *spi_msg)
{
	int ret;
	struct spi_geni_master *mas = spi_master_get_devdata(spi);

	if (spi_geni_is_abort_still_pending(mas))
		return -EBUSY;

	ret = setup_fifo_params(spi_msg->spi, spi);
	if (ret)
		dev_err(mas->dev, "Couldn't select mode %d\n", ret);
	return ret;
}

static int spi_geni_init(struct spi_geni_master *mas)
{
	struct geni_se *se = &mas->se;
	unsigned int proto, major, minor, ver;
	u32 spi_tx_cfg;

	pm_runtime_get_sync(mas->dev);

	proto = geni_se_read_proto(se);
	if (proto != GENI_SE_SPI) {
		dev_err(mas->dev, "Invalid proto %d\n", proto);
		pm_runtime_put(mas->dev);
		return -ENXIO;
	}
	mas->tx_fifo_depth = geni_se_get_tx_fifo_depth(se);

	/* Width of Tx and Rx FIFO is same */
	mas->fifo_width_bits = geni_se_get_tx_fifo_width(se);

	/*
	 * Hardware programming guide suggests to configure
	 * RX FIFO RFR level to fifo_depth-2.
	 */
	geni_se_init(se, mas->tx_fifo_depth - 3, mas->tx_fifo_depth - 2);
	/* Transmit an entire FIFO worth of data per IRQ */
	mas->tx_wm = 1;
	ver = geni_se_get_qup_hw_version(se);
	major = GENI_SE_VERSION_MAJOR(ver);
	minor = GENI_SE_VERSION_MINOR(ver);

	if (major == 1 && minor == 0)
		mas->oversampling = 2;
	else
		mas->oversampling = 1;

	geni_se_select_mode(se, GENI_SE_FIFO);

	/* We always control CS manually */
	spi_tx_cfg = readl(se->base + SE_SPI_TRANS_CFG);
	spi_tx_cfg &= ~CS_TOGGLE;
	writel(spi_tx_cfg, se->base + SE_SPI_TRANS_CFG);

	pm_runtime_put(mas->dev);
	return 0;
}

static unsigned int geni_byte_per_fifo_word(struct spi_geni_master *mas)
{
	/*
	 * Calculate how many bytes we'll put in each FIFO word.  If the
	 * transfer words don't pack cleanly into a FIFO word we'll just put
	 * one transfer word in each FIFO word.  If they do pack we'll pack 'em.
	 */
	if (mas->fifo_width_bits % mas->cur_bits_per_word)
		return roundup_pow_of_two(DIV_ROUND_UP(mas->cur_bits_per_word,
						       BITS_PER_BYTE));

	return mas->fifo_width_bits / BITS_PER_BYTE;
}

static bool geni_spi_handle_tx(struct spi_geni_master *mas)
{
	struct geni_se *se = &mas->se;
	unsigned int max_bytes;
	const u8 *tx_buf;
	unsigned int bytes_per_fifo_word = geni_byte_per_fifo_word(mas);
	unsigned int i = 0;

	/* Stop the watermark IRQ if nothing to send */
	if (!mas->cur_xfer) {
		writel(0, se->base + SE_GENI_TX_WATERMARK_REG);
		return false;
	}

	max_bytes = (mas->tx_fifo_depth - mas->tx_wm) * bytes_per_fifo_word;
	if (mas->tx_rem_bytes < max_bytes)
		max_bytes = mas->tx_rem_bytes;

	tx_buf = mas->cur_xfer->tx_buf + mas->cur_xfer->len - mas->tx_rem_bytes;
	while (i < max_bytes) {
		unsigned int j;
		unsigned int bytes_to_write;
		u32 fifo_word = 0;
		u8 *fifo_byte = (u8 *)&fifo_word;

		bytes_to_write = min(bytes_per_fifo_word, max_bytes - i);
		for (j = 0; j < bytes_to_write; j++)
			fifo_byte[j] = tx_buf[i++];
		iowrite32_rep(se->base + SE_GENI_TX_FIFOn, &fifo_word, 1);
	}
	mas->tx_rem_bytes -= max_bytes;
	if (!mas->tx_rem_bytes) {
		writel(0, se->base + SE_GENI_TX_WATERMARK_REG);
		return false;
	}
	return true;
}

static void geni_spi_handle_rx(struct spi_geni_master *mas)
{
	struct geni_se *se = &mas->se;
	u32 rx_fifo_status;
	unsigned int rx_bytes;
	unsigned int rx_last_byte_valid;
	u8 *rx_buf;
	unsigned int bytes_per_fifo_word = geni_byte_per_fifo_word(mas);
	unsigned int i = 0;

	rx_fifo_status = readl(se->base + SE_GENI_RX_FIFO_STATUS);
	rx_bytes = (rx_fifo_status & RX_FIFO_WC_MSK) * bytes_per_fifo_word;
	if (rx_fifo_status & RX_LAST) {
		rx_last_byte_valid = rx_fifo_status & RX_LAST_BYTE_VALID_MSK;
		rx_last_byte_valid >>= RX_LAST_BYTE_VALID_SHFT;
		if (rx_last_byte_valid && rx_last_byte_valid < 4)
			rx_bytes -= bytes_per_fifo_word - rx_last_byte_valid;
	}

	/* Clear out the FIFO and bail if nowhere to put it */
	if (!mas->cur_xfer) {
		for (i = 0; i < DIV_ROUND_UP(rx_bytes, bytes_per_fifo_word); i++)
			readl(se->base + SE_GENI_RX_FIFOn);
		return;
	}

	if (mas->rx_rem_bytes < rx_bytes)
		rx_bytes = mas->rx_rem_bytes;

	rx_buf = mas->cur_xfer->rx_buf + mas->cur_xfer->len - mas->rx_rem_bytes;
	while (i < rx_bytes) {
		u32 fifo_word = 0;
		u8 *fifo_byte = (u8 *)&fifo_word;
		unsigned int bytes_to_read;
		unsigned int j;

		bytes_to_read = min(bytes_per_fifo_word, rx_bytes - i);
		ioread32_rep(se->base + SE_GENI_RX_FIFOn, &fifo_word, 1);
		for (j = 0; j < bytes_to_read; j++)
			rx_buf[i++] = fifo_byte[j];
	}
	mas->rx_rem_bytes -= rx_bytes;
}

static void setup_fifo_xfer(struct spi_transfer *xfer,
				struct spi_geni_master *mas,
				u16 mode, struct spi_master *spi)
{
	u32 m_cmd = 0;
	u32 len;
	struct geni_se *se = &mas->se;
	int ret;

	/*
	 * Ensure that our interrupt handler isn't still running from some
	 * prior command before we start messing with the hardware behind
	 * its back.  We don't need to _keep_ the lock here since we're only
	 * worried about racing with out interrupt handler.  The SPI core
	 * already handles making sure that we're not trying to do two
	 * transfers at once or setting a chip select and doing a transfer
	 * concurrently.
	 *
	 * NOTE: we actually _can't_ hold the lock here because possibly we
	 * might call clk_set_rate() which needs to be able to sleep.
	 */
	spin_lock_irq(&mas->lock);
	spin_unlock_irq(&mas->lock);

	if (xfer->bits_per_word != mas->cur_bits_per_word) {
		spi_setup_word_len(mas, mode, xfer->bits_per_word);
		mas->cur_bits_per_word = xfer->bits_per_word;
	}

	/* Speed and bits per word can be overridden per transfer */
	ret = geni_spi_set_clock_and_bw(mas, xfer->speed_hz);
	if (ret)
		return;

	mas->tx_rem_bytes = 0;
	mas->rx_rem_bytes = 0;

	if (!(mas->cur_bits_per_word % MIN_WORD_LEN))
		len = xfer->len * BITS_PER_BYTE / mas->cur_bits_per_word;
	else
		len = xfer->len / (mas->cur_bits_per_word / BITS_PER_BYTE + 1);
	len &= TRANS_LEN_MSK;

	mas->cur_xfer = xfer;
	if (xfer->tx_buf) {
		m_cmd |= SPI_TX_ONLY;
		mas->tx_rem_bytes = xfer->len;
		writel(len, se->base + SE_SPI_TX_TRANS_LEN);
	}

	if (xfer->rx_buf) {
		m_cmd |= SPI_RX_ONLY;
		writel(len, se->base + SE_SPI_RX_TRANS_LEN);
		mas->rx_rem_bytes = xfer->len;
	}

	/*
	 * Lock around right before we start the transfer since our
	 * interrupt could come in at any time now.
	 */
	spin_lock_irq(&mas->lock);
	geni_se_setup_m_cmd(se, m_cmd, FRAGMENTATION);

	/*
	 * TX_WATERMARK_REG should be set after SPI configuration and
	 * setting up GENI SE engine, as driver starts data transfer
	 * for the watermark interrupt.
	 */
	if (m_cmd & SPI_TX_ONLY) {
		if (geni_spi_handle_tx(mas))
			writel(mas->tx_wm, se->base + SE_GENI_TX_WATERMARK_REG);
	}
	spin_unlock_irq(&mas->lock);
}

static int spi_geni_transfer_one(struct spi_master *spi,
				struct spi_device *slv,
				struct spi_transfer *xfer)
{
	struct spi_geni_master *mas = spi_master_get_devdata(spi);

	if (spi_geni_is_abort_still_pending(mas))
		return -EBUSY;

	/* Terminate and return success for 0 byte length transfer */
	if (!xfer->len)
		return 0;

	setup_fifo_xfer(xfer, mas, slv->mode, spi);
	return 1;
}

static irqreturn_t geni_spi_isr(int irq, void *data)
{
	struct spi_master *spi = data;
	struct spi_geni_master *mas = spi_master_get_devdata(spi);
	struct geni_se *se = &mas->se;
	u32 m_irq;

	m_irq = readl(se->base + SE_GENI_M_IRQ_STATUS);
	if (!m_irq)
		return IRQ_NONE;

	if (m_irq & (M_CMD_OVERRUN_EN | M_ILLEGAL_CMD_EN | M_CMD_FAILURE_EN |
		     M_RX_FIFO_RD_ERR_EN | M_RX_FIFO_WR_ERR_EN |
		     M_TX_FIFO_RD_ERR_EN | M_TX_FIFO_WR_ERR_EN))
		dev_warn(mas->dev, "Unexpected IRQ err status %#010x\n", m_irq);

	spin_lock(&mas->lock);

	if ((m_irq & M_RX_FIFO_WATERMARK_EN) || (m_irq & M_RX_FIFO_LAST_EN))
		geni_spi_handle_rx(mas);

	if (m_irq & M_TX_FIFO_WATERMARK_EN)
		geni_spi_handle_tx(mas);

	if (m_irq & M_CMD_DONE_EN) {
		if (mas->cur_xfer) {
			spi_finalize_current_transfer(spi);
			mas->cur_xfer = NULL;
			/*
			 * If this happens, then a CMD_DONE came before all the
			 * Tx buffer bytes were sent out. This is unusual, log
			 * this condition and disable the WM interrupt to
			 * prevent the system from stalling due an interrupt
			 * storm.
			 *
			 * If this happens when all Rx bytes haven't been
			 * received, log the condition. The only known time
			 * this can happen is if bits_per_word != 8 and some
			 * registers that expect xfer lengths in num spi_words
			 * weren't written correctly.
			 */
			if (mas->tx_rem_bytes) {
				writel(0, se->base + SE_GENI_TX_WATERMARK_REG);
				dev_err(mas->dev, "Premature done. tx_rem = %d bpw%d\n",
					mas->tx_rem_bytes, mas->cur_bits_per_word);
			}
			if (mas->rx_rem_bytes)
				dev_err(mas->dev, "Premature done. rx_rem = %d bpw%d\n",
					mas->rx_rem_bytes, mas->cur_bits_per_word);
		} else {
			complete(&mas->cs_done);
		}
	}

	if (m_irq & M_CMD_CANCEL_EN)
		complete(&mas->cancel_done);
	if (m_irq & M_CMD_ABORT_EN)
		complete(&mas->abort_done);

	/*
	 * It's safe or a good idea to Ack all of our our interrupts at the
	 * end of the function. Specifically:
	 * - M_CMD_DONE_EN / M_RX_FIFO_LAST_EN: Edge triggered interrupts and
	 *   clearing Acks. Clearing at the end relies on nobody else having
	 *   started a new transfer yet or else we could be clearing _their_
	 *   done bit, but everyone grabs the spinlock before starting a new
	 *   transfer.
	 * - M_RX_FIFO_WATERMARK_EN / M_TX_FIFO_WATERMARK_EN: These appear
	 *   to be "latched level" interrupts so it's important to clear them
	 *   _after_ you've handled the condition and always safe to do so
	 *   since they'll re-assert if they're still happening.
	 */
	writel(m_irq, se->base + SE_GENI_M_IRQ_CLEAR);

	spin_unlock(&mas->lock);

	return IRQ_HANDLED;
}

static int spi_geni_probe(struct platform_device *pdev)
{
	int ret, irq;
	struct spi_master *spi;
	struct spi_geni_master *mas;
	void __iomem *base;
	struct clk *clk;
	struct device *dev = &pdev->dev;

	irq = platform_get_irq(pdev, 0);
	if (irq < 0)
		return irq;

	base = devm_platform_ioremap_resource(pdev, 0);
	if (IS_ERR(base))
		return PTR_ERR(base);

	clk = devm_clk_get(dev, "se");
	if (IS_ERR(clk))
		return PTR_ERR(clk);

	spi = devm_spi_alloc_master(dev, sizeof(*mas));
	if (!spi)
		return -ENOMEM;

	platform_set_drvdata(pdev, spi);
	mas = spi_master_get_devdata(spi);
	mas->irq = irq;
	mas->dev = dev;
	mas->se.dev = dev;
	mas->se.wrapper = dev_get_drvdata(dev->parent);
	mas->se.base = base;
	mas->se.clk = clk;

	ret = devm_pm_opp_set_clkname(&pdev->dev, "se");
	if (ret)
		return ret;
	/* OPP table is optional */
	ret = devm_pm_opp_of_add_table(&pdev->dev);
	if (ret && ret != -ENODEV) {
		dev_err(&pdev->dev, "invalid OPP table in device tree\n");
		return ret;
	}

	spi->bus_num = -1;
	spi->dev.of_node = dev->of_node;
	spi->mode_bits = SPI_CPOL | SPI_CPHA | SPI_LOOP | SPI_CS_HIGH;
	spi->bits_per_word_mask = SPI_BPW_RANGE_MASK(4, 32);
	spi->num_chipselect = 4;
	spi->max_speed_hz = 50000000;
	spi->prepare_message = spi_geni_prepare_message;
	spi->transfer_one = spi_geni_transfer_one;
	spi->auto_runtime_pm = true;
	spi->handle_err = handle_fifo_timeout;
	spi->set_cs = spi_geni_set_cs;
	spi->use_gpio_descriptors = true;

	init_completion(&mas->cs_done);
	init_completion(&mas->cancel_done);
	init_completion(&mas->abort_done);
	spin_lock_init(&mas->lock);
	pm_runtime_use_autosuspend(&pdev->dev);
	pm_runtime_set_autosuspend_delay(&pdev->dev, 250);
	pm_runtime_enable(dev);

	ret = geni_icc_get(&mas->se, NULL);
	if (ret)
		goto spi_geni_probe_runtime_disable;
	/* Set the bus quota to a reasonable value for register access */
	mas->se.icc_paths[GENI_TO_CORE].avg_bw = Bps_to_icc(CORE_2X_50_MHZ);
	mas->se.icc_paths[CPU_TO_GENI].avg_bw = GENI_DEFAULT_BW;

	ret = geni_icc_set_bw(&mas->se);
	if (ret)
		goto spi_geni_probe_runtime_disable;

	ret = spi_geni_init(mas);
	if (ret)
		goto spi_geni_probe_runtime_disable;

	ret = request_irq(mas->irq, geni_spi_isr, 0, dev_name(dev), spi);
	if (ret)
		goto spi_geni_probe_runtime_disable;

	ret = spi_register_master(spi);
	if (ret)
		goto spi_geni_probe_free_irq;

	return 0;
spi_geni_probe_free_irq:
	free_irq(mas->irq, spi);
spi_geni_probe_runtime_disable:
	pm_runtime_disable(dev);
	return ret;
}

static int spi_geni_remove(struct platform_device *pdev)
{
	struct spi_master *spi = platform_get_drvdata(pdev);
	struct spi_geni_master *mas = spi_master_get_devdata(spi);

	/* Unregister _before_ disabling pm_runtime() so we stop transfers */
	spi_unregister_master(spi);

	free_irq(mas->irq, spi);
	pm_runtime_disable(&pdev->dev);
	return 0;
}

static int __maybe_unused spi_geni_runtime_suspend(struct device *dev)
{
	struct spi_master *spi = dev_get_drvdata(dev);
	struct spi_geni_master *mas = spi_master_get_devdata(spi);
	int ret;

	/* Drop the performance state vote */
	dev_pm_opp_set_rate(dev, 0);

	ret = geni_se_resources_off(&mas->se);
	if (ret)
		return ret;

	return geni_icc_disable(&mas->se);
}

static int __maybe_unused spi_geni_runtime_resume(struct device *dev)
{
	struct spi_master *spi = dev_get_drvdata(dev);
	struct spi_geni_master *mas = spi_master_get_devdata(spi);
	int ret;

	ret = geni_icc_enable(&mas->se);
	if (ret)
		return ret;

	ret = geni_se_resources_on(&mas->se);
	if (ret)
		return ret;

	return dev_pm_opp_set_rate(mas->dev, mas->cur_sclk_hz);
}

static int __maybe_unused spi_geni_suspend(struct device *dev)
{
	struct spi_master *spi = dev_get_drvdata(dev);
	int ret;

	ret = spi_master_suspend(spi);
	if (ret)
		return ret;

	ret = pm_runtime_force_suspend(dev);
	if (ret)
		spi_master_resume(spi);

	return ret;
}

static int __maybe_unused spi_geni_resume(struct device *dev)
{
	struct spi_master *spi = dev_get_drvdata(dev);
	int ret;

	ret = pm_runtime_force_resume(dev);
	if (ret)
		return ret;

	ret = spi_master_resume(spi);
	if (ret)
		pm_runtime_force_suspend(dev);

	return ret;
}

static const struct dev_pm_ops spi_geni_pm_ops = {
	SET_RUNTIME_PM_OPS(spi_geni_runtime_suspend,
					spi_geni_runtime_resume, NULL)
	SET_SYSTEM_SLEEP_PM_OPS(spi_geni_suspend, spi_geni_resume)
};

static const struct of_device_id spi_geni_dt_match[] = {
	{ .compatible = "qcom,geni-spi" },
	{}
};
MODULE_DEVICE_TABLE(of, spi_geni_dt_match);

static struct platform_driver spi_geni_driver = {
	.probe  = spi_geni_probe,
	.remove = spi_geni_remove,
	.driver = {
		.name = "geni_spi",
		.pm = &spi_geni_pm_ops,
		.of_match_table = spi_geni_dt_match,
	},
};
module_platform_driver(spi_geni_driver);

MODULE_DESCRIPTION("SPI driver for GENI based QUP cores");
MODULE_LICENSE("GPL v2");