aboutsummaryrefslogtreecommitdiff
path: root/drivers/usb/musb/musb_cppi41.c
blob: 16363852c0346b28b6452e04eddedfc630635428 (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
#include <linux/device.h>
#include <linux/dma-mapping.h>
#include <linux/dmaengine.h>
#include <linux/sizes.h>
#include <linux/platform_device.h>
#include <linux/of.h>

#include "cppi_dma.h"
#include "musb_core.h"
#include "musb_trace.h"

#define RNDIS_REG(x) (0x80 + ((x - 1) * 4))

#define EP_MODE_AUTOREQ_NONE		0
#define EP_MODE_AUTOREQ_ALL_NEOP	1
#define EP_MODE_AUTOREQ_ALWAYS		3

#define EP_MODE_DMA_TRANSPARENT		0
#define EP_MODE_DMA_RNDIS		1
#define EP_MODE_DMA_GEN_RNDIS		3

#define USB_CTRL_TX_MODE	0x70
#define USB_CTRL_RX_MODE	0x74
#define USB_CTRL_AUTOREQ	0xd0
#define USB_TDOWN		0xd8

#define MUSB_DMA_NUM_CHANNELS 15

struct cppi41_dma_controller {
	struct dma_controller controller;
	struct cppi41_dma_channel rx_channel[MUSB_DMA_NUM_CHANNELS];
	struct cppi41_dma_channel tx_channel[MUSB_DMA_NUM_CHANNELS];
	struct musb *musb;
	struct hrtimer early_tx;
	struct list_head early_tx_list;
	u32 rx_mode;
	u32 tx_mode;
	u32 auto_req;
};

static void save_rx_toggle(struct cppi41_dma_channel *cppi41_channel)
{
	u16 csr;
	u8 toggle;

	if (cppi41_channel->is_tx)
		return;
	if (!is_host_active(cppi41_channel->controller->musb))
		return;

	csr = musb_readw(cppi41_channel->hw_ep->regs, MUSB_RXCSR);
	toggle = csr & MUSB_RXCSR_H_DATATOGGLE ? 1 : 0;

	cppi41_channel->usb_toggle = toggle;
}

static void update_rx_toggle(struct cppi41_dma_channel *cppi41_channel)
{
	struct musb_hw_ep *hw_ep = cppi41_channel->hw_ep;
	struct musb *musb = hw_ep->musb;
	u16 csr;
	u8 toggle;

	if (cppi41_channel->is_tx)
		return;
	if (!is_host_active(musb))
		return;

	musb_ep_select(musb->mregs, hw_ep->epnum);
	csr = musb_readw(hw_ep->regs, MUSB_RXCSR);
	toggle = csr & MUSB_RXCSR_H_DATATOGGLE ? 1 : 0;

	/*
	 * AM335x Advisory 1.0.13: Due to internal synchronisation error the
	 * data toggle may reset from DATA1 to DATA0 during receiving data from
	 * more than one endpoint.
	 */
	if (!toggle && toggle == cppi41_channel->usb_toggle) {
		csr |= MUSB_RXCSR_H_DATATOGGLE | MUSB_RXCSR_H_WR_DATATOGGLE;
		musb_writew(cppi41_channel->hw_ep->regs, MUSB_RXCSR, csr);
		musb_dbg(cppi41_channel->controller->musb,
				"Restoring DATA1 toggle.");
	}

	cppi41_channel->usb_toggle = toggle;
}

static bool musb_is_tx_fifo_empty(struct musb_hw_ep *hw_ep)
{
	u8		epnum = hw_ep->epnum;
	struct musb	*musb = hw_ep->musb;
	void __iomem	*epio = musb->endpoints[epnum].regs;
	u16		csr;

	musb_ep_select(musb->mregs, hw_ep->epnum);
	csr = musb_readw(epio, MUSB_TXCSR);
	if (csr & MUSB_TXCSR_TXPKTRDY)
		return false;
	return true;
}

static void cppi41_dma_callback(void *private_data);

static void cppi41_trans_done(struct cppi41_dma_channel *cppi41_channel)
{
	struct musb_hw_ep *hw_ep = cppi41_channel->hw_ep;
	struct musb *musb = hw_ep->musb;
	void __iomem *epio = hw_ep->regs;
	u16 csr;

	if (!cppi41_channel->prog_len ||
	    (cppi41_channel->channel.status == MUSB_DMA_STATUS_FREE)) {

		/* done, complete */
		cppi41_channel->channel.actual_len =
			cppi41_channel->transferred;
		cppi41_channel->channel.status = MUSB_DMA_STATUS_FREE;
		cppi41_channel->channel.rx_packet_done = true;

		/*
		 * transmit ZLP using PIO mode for transfers which size is
		 * multiple of EP packet size.
		 */
		if (cppi41_channel->tx_zlp && (cppi41_channel->transferred %
					cppi41_channel->packet_sz) == 0) {
			musb_ep_select(musb->mregs, hw_ep->epnum);
			csr = MUSB_TXCSR_MODE | MUSB_TXCSR_TXPKTRDY;
			musb_writew(epio, MUSB_TXCSR, csr);
		}

		trace_musb_cppi41_done(cppi41_channel);
		musb_dma_completion(musb, hw_ep->epnum, cppi41_channel->is_tx);
	} else {
		/* next iteration, reload */
		struct dma_chan *dc = cppi41_channel->dc;
		struct dma_async_tx_descriptor *dma_desc;
		enum dma_transfer_direction direction;
		u32 remain_bytes;

		cppi41_channel->buf_addr += cppi41_channel->packet_sz;

		remain_bytes = cppi41_channel->total_len;
		remain_bytes -= cppi41_channel->transferred;
		remain_bytes = min(remain_bytes, cppi41_channel->packet_sz);
		cppi41_channel->prog_len = remain_bytes;

		direction = cppi41_channel->is_tx ? DMA_MEM_TO_DEV
			: DMA_DEV_TO_MEM;
		dma_desc = dmaengine_prep_slave_single(dc,
				cppi41_channel->buf_addr,
				remain_bytes,
				direction,
				DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
		if (WARN_ON(!dma_desc))
			return;

		dma_desc->callback = cppi41_dma_callback;
		dma_desc->callback_param = &cppi41_channel->channel;
		cppi41_channel->cookie = dma_desc->tx_submit(dma_desc);
		trace_musb_cppi41_cont(cppi41_channel);
		dma_async_issue_pending(dc);

		if (!cppi41_channel->is_tx) {
			musb_ep_select(musb->mregs, hw_ep->epnum);
			csr = musb_readw(epio, MUSB_RXCSR);
			csr |= MUSB_RXCSR_H_REQPKT;
			musb_writew(epio, MUSB_RXCSR, csr);
		}
	}
}

static enum hrtimer_restart cppi41_recheck_tx_req(struct hrtimer *timer)
{
	struct cppi41_dma_controller *controller;
	struct cppi41_dma_channel *cppi41_channel, *n;
	struct musb *musb;
	unsigned long flags;
	enum hrtimer_restart ret = HRTIMER_NORESTART;

	controller = container_of(timer, struct cppi41_dma_controller,
			early_tx);
	musb = controller->musb;

	spin_lock_irqsave(&musb->lock, flags);
	list_for_each_entry_safe(cppi41_channel, n, &controller->early_tx_list,
			tx_check) {
		bool empty;
		struct musb_hw_ep *hw_ep = cppi41_channel->hw_ep;

		empty = musb_is_tx_fifo_empty(hw_ep);
		if (empty) {
			list_del_init(&cppi41_channel->tx_check);
			cppi41_trans_done(cppi41_channel);
		}
	}

	if (!list_empty(&controller->early_tx_list) &&
	    !hrtimer_is_queued(&controller->early_tx)) {
		ret = HRTIMER_RESTART;
		hrtimer_forward_now(&controller->early_tx, 20 * NSEC_PER_USEC);
	}

	spin_unlock_irqrestore(&musb->lock, flags);
	return ret;
}

static void cppi41_dma_callback(void *private_data)
{
	struct dma_channel *channel = private_data;
	struct cppi41_dma_channel *cppi41_channel = channel->private_data;
	struct musb_hw_ep *hw_ep = cppi41_channel->hw_ep;
	struct cppi41_dma_controller *controller;
	struct musb *musb = hw_ep->musb;
	unsigned long flags;
	struct dma_tx_state txstate;
	u32 transferred;
	int is_hs = 0;
	bool empty;

	spin_lock_irqsave(&musb->lock, flags);

	dmaengine_tx_status(cppi41_channel->dc, cppi41_channel->cookie,
			&txstate);
	transferred = cppi41_channel->prog_len - txstate.residue;
	cppi41_channel->transferred += transferred;

	trace_musb_cppi41_gb(cppi41_channel);
	update_rx_toggle(cppi41_channel);

	if (cppi41_channel->transferred == cppi41_channel->total_len ||
			transferred < cppi41_channel->packet_sz)
		cppi41_channel->prog_len = 0;

	if (cppi41_channel->is_tx)
		empty = musb_is_tx_fifo_empty(hw_ep);

	if (!cppi41_channel->is_tx || empty) {
		cppi41_trans_done(cppi41_channel);
		goto out;
	}

	/*
	 * On AM335x it has been observed that the TX interrupt fires
	 * too early that means the TXFIFO is not yet empty but the DMA
	 * engine says that it is done with the transfer. We don't
	 * receive a FIFO empty interrupt so the only thing we can do is
	 * to poll for the bit. On HS it usually takes 2us, on FS around
	 * 110us - 150us depending on the transfer size.
	 * We spin on HS (no longer than than 25us and setup a timer on
	 * FS to check for the bit and complete the transfer.
	 */
	controller = cppi41_channel->controller;

	if (is_host_active(musb)) {
		if (musb->port1_status & USB_PORT_STAT_HIGH_SPEED)
			is_hs = 1;
	} else {
		if (musb->g.speed == USB_SPEED_HIGH)
			is_hs = 1;
	}
	if (is_hs) {
		unsigned wait = 25;

		do {
			empty = musb_is_tx_fifo_empty(hw_ep);
			if (empty) {
				cppi41_trans_done(cppi41_channel);
				goto out;
			}
			wait--;
			if (!wait)
				break;
			cpu_relax();
		} while (1);
	}
	list_add_tail(&cppi41_channel->tx_check,
			&controller->early_tx_list);
	if (!hrtimer_is_queued(&controller->early_tx)) {
		unsigned long usecs = cppi41_channel->total_len / 10;

		hrtimer_start_range_ns(&controller->early_tx,
				       usecs * NSEC_PER_USEC,
				       20 * NSEC_PER_USEC,
				       HRTIMER_MODE_REL);
	}

out:
	spin_unlock_irqrestore(&musb->lock, flags);
}

static u32 update_ep_mode(unsigned ep, unsigned mode, u32 old)
{
	unsigned shift;

	shift = (ep - 1) * 2;
	old &= ~(3 << shift);
	old |= mode << shift;
	return old;
}

static void cppi41_set_dma_mode(struct cppi41_dma_channel *cppi41_channel,
		unsigned mode)
{
	struct cppi41_dma_controller *controller = cppi41_channel->controller;
	u32 port;
	u32 new_mode;
	u32 old_mode;

	if (cppi41_channel->is_tx)
		old_mode = controller->tx_mode;
	else
		old_mode = controller->rx_mode;
	port = cppi41_channel->port_num;
	new_mode = update_ep_mode(port, mode, old_mode);

	if (new_mode == old_mode)
		return;
	if (cppi41_channel->is_tx) {
		controller->tx_mode = new_mode;
		musb_writel(controller->musb->ctrl_base, USB_CTRL_TX_MODE,
				new_mode);
	} else {
		controller->rx_mode = new_mode;
		musb_writel(controller->musb->ctrl_base, USB_CTRL_RX_MODE,
				new_mode);
	}
}

static void cppi41_set_autoreq_mode(struct cppi41_dma_channel *cppi41_channel,
		unsigned mode)
{
	struct cppi41_dma_controller *controller = cppi41_channel->controller;
	u32 port;
	u32 new_mode;
	u32 old_mode;

	old_mode = controller->auto_req;
	port = cppi41_channel->port_num;
	new_mode = update_ep_mode(port, mode, old_mode);

	if (new_mode == old_mode)
		return;
	controller->auto_req = new_mode;
	musb_writel(controller->musb->ctrl_base, USB_CTRL_AUTOREQ, new_mode);
}

static bool cppi41_configure_channel(struct dma_channel *channel,
				u16 packet_sz, u8 mode,
				dma_addr_t dma_addr, u32 len)
{
	struct cppi41_dma_channel *cppi41_channel = channel->private_data;
	struct dma_chan *dc = cppi41_channel->dc;
	struct dma_async_tx_descriptor *dma_desc;
	enum dma_transfer_direction direction;
	struct musb *musb = cppi41_channel->controller->musb;
	unsigned use_gen_rndis = 0;

	cppi41_channel->buf_addr = dma_addr;
	cppi41_channel->total_len = len;
	cppi41_channel->transferred = 0;
	cppi41_channel->packet_sz = packet_sz;
	cppi41_channel->tx_zlp = (cppi41_channel->is_tx && mode) ? 1 : 0;

	/*
	 * Due to AM335x' Advisory 1.0.13 we are not allowed to transfer more
	 * than max packet size at a time.
	 */
	if (cppi41_channel->is_tx)
		use_gen_rndis = 1;

	if (use_gen_rndis) {
		/* RNDIS mode */
		if (len > packet_sz) {
			musb_writel(musb->ctrl_base,
				RNDIS_REG(cppi41_channel->port_num), len);
			/* gen rndis */
			cppi41_set_dma_mode(cppi41_channel,
					EP_MODE_DMA_GEN_RNDIS);

			/* auto req */
			cppi41_set_autoreq_mode(cppi41_channel,
					EP_MODE_AUTOREQ_ALL_NEOP);
		} else {
			musb_writel(musb->ctrl_base,
					RNDIS_REG(cppi41_channel->port_num), 0);
			cppi41_set_dma_mode(cppi41_channel,
					EP_MODE_DMA_TRANSPARENT);
			cppi41_set_autoreq_mode(cppi41_channel,
					EP_MODE_AUTOREQ_NONE);
		}
	} else {
		/* fallback mode */
		cppi41_set_dma_mode(cppi41_channel, EP_MODE_DMA_TRANSPARENT);
		cppi41_set_autoreq_mode(cppi41_channel, EP_MODE_AUTOREQ_NONE);
		len = min_t(u32, packet_sz, len);
	}
	cppi41_channel->prog_len = len;
	direction = cppi41_channel->is_tx ? DMA_MEM_TO_DEV : DMA_DEV_TO_MEM;
	dma_desc = dmaengine_prep_slave_single(dc, dma_addr, len, direction,
			DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
	if (!dma_desc)
		return false;

	dma_desc->callback = cppi41_dma_callback;
	dma_desc->callback_param = channel;
	cppi41_channel->cookie = dma_desc->tx_submit(dma_desc);
	cppi41_channel->channel.rx_packet_done = false;

	trace_musb_cppi41_config(cppi41_channel);

	save_rx_toggle(cppi41_channel);
	dma_async_issue_pending(dc);
	return true;
}

static struct dma_channel *cppi41_dma_channel_allocate(struct dma_controller *c,
				struct musb_hw_ep *hw_ep, u8 is_tx)
{
	struct cppi41_dma_controller *controller = container_of(c,
			struct cppi41_dma_controller, controller);
	struct cppi41_dma_channel *cppi41_channel = NULL;
	u8 ch_num = hw_ep->epnum - 1;

	if (ch_num >= MUSB_DMA_NUM_CHANNELS)
		return NULL;

	if (is_tx)
		cppi41_channel = &controller->tx_channel[ch_num];
	else
		cppi41_channel = &controller->rx_channel[ch_num];

	if (!cppi41_channel->dc)
		return NULL;

	if (cppi41_channel->is_allocated)
		return NULL;

	cppi41_channel->hw_ep = hw_ep;
	cppi41_channel->is_allocated = 1;

	trace_musb_cppi41_alloc(cppi41_channel);
	return &cppi41_channel->channel;
}

static void cppi41_dma_channel_release(struct dma_channel *channel)
{
	struct cppi41_dma_channel *cppi41_channel = channel->private_data;

	trace_musb_cppi41_free(cppi41_channel);
	if (cppi41_channel->is_allocated) {
		cppi41_channel->is_allocated = 0;
		channel->status = MUSB_DMA_STATUS_FREE;
		channel->actual_len = 0;
	}
}

static int cppi41_dma_channel_program(struct dma_channel *channel,
				u16 packet_sz, u8 mode,
				dma_addr_t dma_addr, u32 len)
{
	int ret;
	struct cppi41_dma_channel *cppi41_channel = channel->private_data;
	int hb_mult = 0;

	BUG_ON(channel->status == MUSB_DMA_STATUS_UNKNOWN ||
		channel->status == MUSB_DMA_STATUS_BUSY);

	if (is_host_active(cppi41_channel->controller->musb)) {
		if (cppi41_channel->is_tx)
			hb_mult = cppi41_channel->hw_ep->out_qh->hb_mult;
		else
			hb_mult = cppi41_channel->hw_ep->in_qh->hb_mult;
	}

	channel->status = MUSB_DMA_STATUS_BUSY;
	channel->actual_len = 0;

	if (hb_mult)
		packet_sz = hb_mult * (packet_sz & 0x7FF);

	ret = cppi41_configure_channel(channel, packet_sz, mode, dma_addr, len);
	if (!ret)
		channel->status = MUSB_DMA_STATUS_FREE;

	return ret;
}

static int cppi41_is_compatible(struct dma_channel *channel, u16 maxpacket,
		void *buf, u32 length)
{
	struct cppi41_dma_channel *cppi41_channel = channel->private_data;
	struct cppi41_dma_controller *controller = cppi41_channel->controller;
	struct musb *musb = controller->musb;

	if (is_host_active(musb)) {
		WARN_ON(1);
		return 1;
	}
	if (cppi41_channel->hw_ep->ep_in.type != USB_ENDPOINT_XFER_BULK)
		return 0;
	if (cppi41_channel->is_tx)
		return 1;
	/* AM335x Advisory 1.0.13. No workaround for device RX mode */
	return 0;
}

static int cppi41_dma_channel_abort(struct dma_channel *channel)
{
	struct cppi41_dma_channel *cppi41_channel = channel->private_data;
	struct cppi41_dma_controller *controller = cppi41_channel->controller;
	struct musb *musb = controller->musb;
	void __iomem *epio = cppi41_channel->hw_ep->regs;
	int tdbit;
	int ret;
	unsigned is_tx;
	u16 csr;

	is_tx = cppi41_channel->is_tx;
	trace_musb_cppi41_abort(cppi41_channel);

	if (cppi41_channel->channel.status == MUSB_DMA_STATUS_FREE)
		return 0;

	list_del_init(&cppi41_channel->tx_check);
	if (is_tx) {
		csr = musb_readw(epio, MUSB_TXCSR);
		csr &= ~MUSB_TXCSR_DMAENAB;
		musb_writew(epio, MUSB_TXCSR, csr);
	} else {
		cppi41_set_autoreq_mode(cppi41_channel, EP_MODE_AUTOREQ_NONE);

		/* delay to drain to cppi dma pipeline for isoch */
		udelay(250);

		csr = musb_readw(epio, MUSB_RXCSR);
		csr &= ~(MUSB_RXCSR_H_REQPKT | MUSB_RXCSR_DMAENAB);
		musb_writew(epio, MUSB_RXCSR, csr);

		/* wait to drain cppi dma pipe line */
		udelay(50);

		csr = musb_readw(epio, MUSB_RXCSR);
		if (csr & MUSB_RXCSR_RXPKTRDY) {
			csr |= MUSB_RXCSR_FLUSHFIFO;
			musb_writew(epio, MUSB_RXCSR, csr);
			musb_writew(epio, MUSB_RXCSR, csr);
		}
	}

	tdbit = 1 << cppi41_channel->port_num;
	if (is_tx)
		tdbit <<= 16;

	do {
		if (is_tx)
			musb_writel(musb->ctrl_base, USB_TDOWN, tdbit);
		ret = dmaengine_terminate_all(cppi41_channel->dc);
	} while (ret == -EAGAIN);

	if (is_tx) {
		musb_writel(musb->ctrl_base, USB_TDOWN, tdbit);

		csr = musb_readw(epio, MUSB_TXCSR);
		if (csr & MUSB_TXCSR_TXPKTRDY) {
			csr |= MUSB_TXCSR_FLUSHFIFO;
			musb_writew(epio, MUSB_TXCSR, csr);
		}
	}

	cppi41_channel->channel.status = MUSB_DMA_STATUS_FREE;
	return 0;
}

static void cppi41_release_all_dma_chans(struct cppi41_dma_controller *ctrl)
{
	struct dma_chan *dc;
	int i;

	for (i = 0; i < MUSB_DMA_NUM_CHANNELS; i++) {
		dc = ctrl->tx_channel[i].dc;
		if (dc)
			dma_release_channel(dc);
		dc = ctrl->rx_channel[i].dc;
		if (dc)
			dma_release_channel(dc);
	}
}

static void cppi41_dma_controller_stop(struct cppi41_dma_controller *controller)
{
	cppi41_release_all_dma_chans(controller);
}

static int cppi41_dma_controller_start(struct cppi41_dma_controller *controller)
{
	struct musb *musb = controller->musb;
	struct device *dev = musb->controller;
	struct device_node *np = dev->parent->of_node;
	struct cppi41_dma_channel *cppi41_channel;
	int count;
	int i;
	int ret;

	count = of_property_count_strings(np, "dma-names");
	if (count < 0)
		return count;

	for (i = 0; i < count; i++) {
		struct dma_chan *dc;
		struct dma_channel *musb_dma;
		const char *str;
		unsigned is_tx;
		unsigned int port;

		ret = of_property_read_string_index(np, "dma-names", i, &str);
		if (ret)
			goto err;
		if (strstarts(str, "tx"))
			is_tx = 1;
		else if (strstarts(str, "rx"))
			is_tx = 0;
		else {
			dev_err(dev, "Wrong dmatype %s\n", str);
			goto err;
		}
		ret = kstrtouint(str + 2, 0, &port);
		if (ret)
			goto err;

		ret = -EINVAL;
		if (port > MUSB_DMA_NUM_CHANNELS || !port)
			goto err;
		if (is_tx)
			cppi41_channel = &controller->tx_channel[port - 1];
		else
			cppi41_channel = &controller->rx_channel[port - 1];

		cppi41_channel->controller = controller;
		cppi41_channel->port_num = port;
		cppi41_channel->is_tx = is_tx;
		INIT_LIST_HEAD(&cppi41_channel->tx_check);

		musb_dma = &cppi41_channel->channel;
		musb_dma->private_data = cppi41_channel;
		musb_dma->status = MUSB_DMA_STATUS_FREE;
		musb_dma->max_len = SZ_4M;

		dc = dma_request_slave_channel(dev->parent, str);
		if (!dc) {
			dev_err(dev, "Failed to request %s.\n", str);
			ret = -EPROBE_DEFER;
			goto err;
		}
		cppi41_channel->dc = dc;
	}
	return 0;
err:
	cppi41_release_all_dma_chans(controller);
	return ret;
}

void cppi41_dma_controller_destroy(struct dma_controller *c)
{
	struct cppi41_dma_controller *controller = container_of(c,
			struct cppi41_dma_controller, controller);

	hrtimer_cancel(&controller->early_tx);
	cppi41_dma_controller_stop(controller);
	kfree(controller);
}
EXPORT_SYMBOL_GPL(cppi41_dma_controller_destroy);

struct dma_controller *
cppi41_dma_controller_create(struct musb *musb, void __iomem *base)
{
	struct cppi41_dma_controller *controller;
	int ret = 0;

	if (!musb->controller->parent->of_node) {
		dev_err(musb->controller, "Need DT for the DMA engine.\n");
		return NULL;
	}

	controller = kzalloc(sizeof(*controller), GFP_KERNEL);
	if (!controller)
		goto kzalloc_fail;

	hrtimer_init(&controller->early_tx, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
	controller->early_tx.function = cppi41_recheck_tx_req;
	INIT_LIST_HEAD(&controller->early_tx_list);
	controller->musb = musb;

	controller->controller.channel_alloc = cppi41_dma_channel_allocate;
	controller->controller.channel_release = cppi41_dma_channel_release;
	controller->controller.channel_program = cppi41_dma_channel_program;
	controller->controller.channel_abort = cppi41_dma_channel_abort;
	controller->controller.is_compatible = cppi41_is_compatible;

	ret = cppi41_dma_controller_start(controller);
	if (ret)
		goto plat_get_fail;
	return &controller->controller;

plat_get_fail:
	kfree(controller);
kzalloc_fail:
	if (ret == -EPROBE_DEFER)
		return ERR_PTR(ret);
	return NULL;
}
EXPORT_SYMBOL_GPL(cppi41_dma_controller_create);