aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/usb/musb/tusb6010_omap.c
blob: 3ce152c0408e6464c93a5e8c46f429753aef38a0 (plain) (blame)
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
/*
 * TUSB6010 USB 2.0 OTG Dual Role controller OMAP DMA interface
 *
 * Copyright (C) 2006 Nokia Corporation
 * Tony Lindgren <tony@atomide.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/usb.h>
#include <linux/platform_device.h>
#include <linux/dma-mapping.h>
#include <linux/slab.h>
#include <linux/omap-dma.h>

#include "musb_core.h"
#include "tusb6010.h"

#define to_chdat(c)		((struct tusb_omap_dma_ch *)(c)->private_data)

#define MAX_DMAREQ		5	/* REVISIT: Really 6, but req5 not OK */

#define OMAP24XX_DMA_EXT_DMAREQ0	2
#define OMAP24XX_DMA_EXT_DMAREQ1	3
#define OMAP242X_DMA_EXT_DMAREQ2	14
#define OMAP242X_DMA_EXT_DMAREQ3	15
#define OMAP242X_DMA_EXT_DMAREQ4	16
#define OMAP242X_DMA_EXT_DMAREQ5	64

struct tusb_omap_dma_ch {
	struct musb		*musb;
	void __iomem		*tbase;
	unsigned long		phys_offset;
	int			epnum;
	u8			tx;
	struct musb_hw_ep	*hw_ep;

	int			ch;
	s8			dmareq;
	s8			sync_dev;

	struct tusb_omap_dma	*tusb_dma;

	dma_addr_t		dma_addr;

	u32			len;
	u16			packet_sz;
	u16			transfer_packet_sz;
	u32			transfer_len;
	u32			completed_len;
};

struct tusb_omap_dma {
	struct dma_controller		controller;
	struct musb			*musb;
	void __iomem			*tbase;

	int				ch;
	s8				dmareq;
	s8				sync_dev;
	unsigned			multichannel:1;
};

/*
 * Allocate dmareq0 to the current channel unless it's already taken
 */
static inline int tusb_omap_use_shared_dmareq(struct tusb_omap_dma_ch *chdat)
{
	u32		reg = musb_readl(chdat->tbase, TUSB_DMA_EP_MAP);

	if (reg != 0) {
		dev_dbg(chdat->musb->controller, "ep%i dmareq0 is busy for ep%i\n",
			chdat->epnum, reg & 0xf);
		return -EAGAIN;
	}

	if (chdat->tx)
		reg = (1 << 4) | chdat->epnum;
	else
		reg = chdat->epnum;

	musb_writel(chdat->tbase, TUSB_DMA_EP_MAP, reg);

	return 0;
}

static inline void tusb_omap_free_shared_dmareq(struct tusb_omap_dma_ch *chdat)
{
	u32		reg = musb_readl(chdat->tbase, TUSB_DMA_EP_MAP);

	if ((reg & 0xf) != chdat->epnum) {
		printk(KERN_ERR "ep%i trying to release dmareq0 for ep%i\n",
			chdat->epnum, reg & 0xf);
		return;
	}
	musb_writel(chdat->tbase, TUSB_DMA_EP_MAP, 0);
}

/*
 * See also musb_dma_completion in plat_uds.c and musb_g_[tx|rx]() in
 * musb_gadget.c.
 */
static void tusb_omap_dma_cb(int lch, u16 ch_status, void *data)
{
	struct dma_channel	*channel = (struct dma_channel *)data;
	struct tusb_omap_dma_ch	*chdat = to_chdat(channel);
	struct tusb_omap_dma	*tusb_dma = chdat->tusb_dma;
	struct musb		*musb = chdat->musb;
	struct device		*dev = musb->controller;
	struct musb_hw_ep	*hw_ep = chdat->hw_ep;
	void __iomem		*ep_conf = hw_ep->conf;
	void __iomem		*mbase = musb->mregs;
	unsigned long		remaining, flags, pio;
	int			ch;

	spin_lock_irqsave(&musb->lock, flags);

	if (tusb_dma->multichannel)
		ch = chdat->ch;
	else
		ch = tusb_dma->ch;

	if (ch_status != OMAP_DMA_BLOCK_IRQ)
		printk(KERN_ERR "TUSB DMA error status: %i\n", ch_status);

	dev_dbg(musb->controller, "ep%i %s dma callback ch: %i status: %x\n",
		chdat->epnum, chdat->tx ? "tx" : "rx",
		ch, ch_status);

	if (chdat->tx)
		remaining = musb_readl(ep_conf, TUSB_EP_TX_OFFSET);
	else
		remaining = musb_readl(ep_conf, TUSB_EP_RX_OFFSET);

	remaining = TUSB_EP_CONFIG_XFR_SIZE(remaining);

	/* HW issue #10: XFR_SIZE may get corrupt on DMA (both async & sync) */
	if (unlikely(remaining > chdat->transfer_len)) {
		dev_dbg(musb->controller, "Corrupt %s dma ch%i XFR_SIZE: 0x%08lx\n",
			chdat->tx ? "tx" : "rx", chdat->ch,
			remaining);
		remaining = 0;
	}

	channel->actual_len = chdat->transfer_len - remaining;
	pio = chdat->len - channel->actual_len;

	dev_dbg(musb->controller, "DMA remaining %lu/%u\n", remaining, chdat->transfer_len);

	/* Transfer remaining 1 - 31 bytes */
	if (pio > 0 && pio < 32) {
		u8	*buf;

		dev_dbg(musb->controller, "Using PIO for remaining %lu bytes\n", pio);
		buf = phys_to_virt((u32)chdat->dma_addr) + chdat->transfer_len;
		if (chdat->tx) {
			dma_unmap_single(dev, chdat->dma_addr,
						chdat->transfer_len,
						DMA_TO_DEVICE);
			musb_write_fifo(hw_ep, pio, buf);
		} else {
			dma_unmap_single(dev, chdat->dma_addr,
						chdat->transfer_len,
						DMA_FROM_DEVICE);
			musb_read_fifo(hw_ep, pio, buf);
		}
		channel->actual_len += pio;
	}

	if (!tusb_dma->multichannel)
		tusb_omap_free_shared_dmareq(chdat);

	channel->status = MUSB_DMA_STATUS_FREE;

	/* Handle only RX callbacks here. TX callbacks must be handled based
	 * on the TUSB DMA status interrupt.
	 * REVISIT: Use both TUSB DMA status interrupt and OMAP DMA callback
	 * interrupt for RX and TX.
	 */
	if (!chdat->tx)
		musb_dma_completion(musb, chdat->epnum, chdat->tx);

	/* We must terminate short tx transfers manually by setting TXPKTRDY.
	 * REVISIT: This same problem may occur with other MUSB dma as well.
	 * Easy to test with g_ether by pinging the MUSB board with ping -s54.
	 */
	if ((chdat->transfer_len < chdat->packet_sz)
			|| (chdat->transfer_len % chdat->packet_sz != 0)) {
		u16	csr;

		if (chdat->tx) {
			dev_dbg(musb->controller, "terminating short tx packet\n");
			musb_ep_select(mbase, chdat->epnum);
			csr = musb_readw(hw_ep->regs, MUSB_TXCSR);
			csr |= MUSB_TXCSR_MODE | MUSB_TXCSR_TXPKTRDY
				| MUSB_TXCSR_P_WZC_BITS;
			musb_writew(hw_ep->regs, MUSB_TXCSR, csr);
		}
	}

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

static int tusb_omap_dma_program(struct dma_channel *channel, u16 packet_sz,
				u8 rndis_mode, dma_addr_t dma_addr, u32 len)
{
	struct tusb_omap_dma_ch		*chdat = to_chdat(channel);
	struct tusb_omap_dma		*tusb_dma = chdat->tusb_dma;
	struct musb			*musb = chdat->musb;
	struct device			*dev = musb->controller;
	struct musb_hw_ep		*hw_ep = chdat->hw_ep;
	void __iomem			*mbase = musb->mregs;
	void __iomem			*ep_conf = hw_ep->conf;
	dma_addr_t			fifo = hw_ep->fifo_sync;
	struct omap_dma_channel_params	dma_params;
	u32				dma_remaining;
	int				src_burst, dst_burst;
	u16				csr;
	int				ch;
	s8				dmareq;
	s8				sync_dev;

	if (unlikely(dma_addr & 0x1) || (len < 32) || (len > packet_sz))
		return false;

	/*
	 * HW issue #10: Async dma will eventually corrupt the XFR_SIZE
	 * register which will cause missed DMA interrupt. We could try to
	 * use a timer for the callback, but it is unsafe as the XFR_SIZE
	 * register is corrupt, and we won't know if the DMA worked.
	 */
	if (dma_addr & 0x2)
		return false;

	/*
	 * Because of HW issue #10, it seems like mixing sync DMA and async
	 * PIO access can confuse the DMA. Make sure XFR_SIZE is reset before
	 * using the channel for DMA.
	 */
	if (chdat->tx)
		dma_remaining = musb_readl(ep_conf, TUSB_EP_TX_OFFSET);
	else
		dma_remaining = musb_readl(ep_conf, TUSB_EP_RX_OFFSET);

	dma_remaining = TUSB_EP_CONFIG_XFR_SIZE(dma_remaining);
	if (dma_remaining) {
		dev_dbg(musb->controller, "Busy %s dma ch%i, not using: %08x\n",
			chdat->tx ? "tx" : "rx", chdat->ch,
			dma_remaining);
		return false;
	}

	chdat->transfer_len = len & ~0x1f;

	if (len < packet_sz)
		chdat->transfer_packet_sz = chdat->transfer_len;
	else
		chdat->transfer_packet_sz = packet_sz;

	if (tusb_dma->multichannel) {
		ch = chdat->ch;
		dmareq = chdat->dmareq;
		sync_dev = chdat->sync_dev;
	} else {
		if (tusb_omap_use_shared_dmareq(chdat) != 0) {
			dev_dbg(musb->controller, "could not get dma for ep%i\n", chdat->epnum);
			return false;
		}
		if (tusb_dma->ch < 0) {
			/* REVISIT: This should get blocked earlier, happens
			 * with MSC ErrorRecoveryTest
			 */
			WARN_ON(1);
			return false;
		}

		ch = tusb_dma->ch;
		dmareq = tusb_dma->dmareq;
		sync_dev = tusb_dma->sync_dev;
		omap_set_dma_callback(ch, tusb_omap_dma_cb, channel);
	}

	chdat->packet_sz = packet_sz;
	chdat->len = len;
	channel->actual_len = 0;
	chdat->dma_addr = dma_addr;
	channel->status = MUSB_DMA_STATUS_BUSY;

	/* Since we're recycling dma areas, we need to clean or invalidate */
	if (chdat->tx)
		dma_map_single(dev, phys_to_virt(dma_addr), len,
				DMA_TO_DEVICE);
	else
		dma_map_single(dev, phys_to_virt(dma_addr), len,
				DMA_FROM_DEVICE);

	/* Use 16-bit transfer if dma_addr is not 32-bit aligned */
	if ((dma_addr & 0x3) == 0) {
		dma_params.data_type = OMAP_DMA_DATA_TYPE_S32;
		dma_params.elem_count = 8;		/* Elements in frame */
	} else {
		dma_params.data_type = OMAP_DMA_DATA_TYPE_S16;
		dma_params.elem_count = 16;		/* Elements in frame */
		fifo = hw_ep->fifo_async;
	}

	dma_params.frame_count	= chdat->transfer_len / 32; /* Burst sz frame */

	dev_dbg(musb->controller, "ep%i %s dma ch%i dma: %08x len: %u(%u) packet_sz: %i(%i)\n",
		chdat->epnum, chdat->tx ? "tx" : "rx",
		ch, dma_addr, chdat->transfer_len, len,
		chdat->transfer_packet_sz, packet_sz);

	/*
	 * Prepare omap DMA for transfer
	 */
	if (chdat->tx) {
		dma_params.src_amode	= OMAP_DMA_AMODE_POST_INC;
		dma_params.src_start	= (unsigned long)dma_addr;
		dma_params.src_ei	= 0;
		dma_params.src_fi	= 0;

		dma_params.dst_amode	= OMAP_DMA_AMODE_DOUBLE_IDX;
		dma_params.dst_start	= (unsigned long)fifo;
		dma_params.dst_ei	= 1;
		dma_params.dst_fi	= -31;	/* Loop 32 byte window */

		dma_params.trigger	= sync_dev;
		dma_params.sync_mode	= OMAP_DMA_SYNC_FRAME;
		dma_params.src_or_dst_synch	= 0;	/* Dest sync */

		src_burst = OMAP_DMA_DATA_BURST_16;	/* 16x32 read */
		dst_burst = OMAP_DMA_DATA_BURST_8;	/* 8x32 write */
	} else {
		dma_params.src_amode	= OMAP_DMA_AMODE_DOUBLE_IDX;
		dma_params.src_start	= (unsigned long)fifo;
		dma_params.src_ei	= 1;
		dma_params.src_fi	= -31;	/* Loop 32 byte window */

		dma_params.dst_amode	= OMAP_DMA_AMODE_POST_INC;
		dma_params.dst_start	= (unsigned long)dma_addr;
		dma_params.dst_ei	= 0;
		dma_params.dst_fi	= 0;

		dma_params.trigger	= sync_dev;
		dma_params.sync_mode	= OMAP_DMA_SYNC_FRAME;
		dma_params.src_or_dst_synch	= 1;	/* Source sync */

		src_burst = OMAP_DMA_DATA_BURST_8;	/* 8x32 read */
		dst_burst = OMAP_DMA_DATA_BURST_16;	/* 16x32 write */
	}

	dev_dbg(musb->controller, "ep%i %s using %i-bit %s dma from 0x%08lx to 0x%08lx\n",
		chdat->epnum, chdat->tx ? "tx" : "rx",
		(dma_params.data_type == OMAP_DMA_DATA_TYPE_S32) ? 32 : 16,
		((dma_addr & 0x3) == 0) ? "sync" : "async",
		dma_params.src_start, dma_params.dst_start);

	omap_set_dma_params(ch, &dma_params);
	omap_set_dma_src_burst_mode(ch, src_burst);
	omap_set_dma_dest_burst_mode(ch, dst_burst);
	omap_set_dma_write_mode(ch, OMAP_DMA_WRITE_LAST_NON_POSTED);

	/*
	 * Prepare MUSB for DMA transfer
	 */
	if (chdat->tx) {
		musb_ep_select(mbase, chdat->epnum);
		csr = musb_readw(hw_ep->regs, MUSB_TXCSR);
		csr |= (MUSB_TXCSR_AUTOSET | MUSB_TXCSR_DMAENAB
			| MUSB_TXCSR_DMAMODE | MUSB_TXCSR_MODE);
		csr &= ~MUSB_TXCSR_P_UNDERRUN;
		musb_writew(hw_ep->regs, MUSB_TXCSR, csr);
	} else {
		musb_ep_select(mbase, chdat->epnum);
		csr = musb_readw(hw_ep->regs, MUSB_RXCSR);
		csr |= MUSB_RXCSR_DMAENAB;
		csr &= ~(MUSB_RXCSR_AUTOCLEAR | MUSB_RXCSR_DMAMODE);
		musb_writew(hw_ep->regs, MUSB_RXCSR,
			csr | MUSB_RXCSR_P_WZC_BITS);
	}

	/*
	 * Start DMA transfer
	 */
	omap_start_dma(ch);

	if (chdat->tx) {
		/* Send transfer_packet_sz packets at a time */
		musb_writel(ep_conf, TUSB_EP_MAX_PACKET_SIZE_OFFSET,
			chdat->transfer_packet_sz);

		musb_writel(ep_conf, TUSB_EP_TX_OFFSET,
			TUSB_EP_CONFIG_XFR_SIZE(chdat->transfer_len));
	} else {
		/* Receive transfer_packet_sz packets at a time */
		musb_writel(ep_conf, TUSB_EP_MAX_PACKET_SIZE_OFFSET,
			chdat->transfer_packet_sz << 16);

		musb_writel(ep_conf, TUSB_EP_RX_OFFSET,
			TUSB_EP_CONFIG_XFR_SIZE(chdat->transfer_len));
	}

	return true;
}

static int tusb_omap_dma_abort(struct dma_channel *channel)
{
	struct tusb_omap_dma_ch	*chdat = to_chdat(channel);
	struct tusb_omap_dma	*tusb_dma = chdat->tusb_dma;

	if (!tusb_dma->multichannel) {
		if (tusb_dma->ch >= 0) {
			omap_stop_dma(tusb_dma->ch);
			omap_free_dma(tusb_dma->ch);
			tusb_dma->ch = -1;
		}

		tusb_dma->dmareq = -1;
		tusb_dma->sync_dev = -1;
	}

	channel->status = MUSB_DMA_STATUS_FREE;

	return 0;
}

static inline int tusb_omap_dma_allocate_dmareq(struct tusb_omap_dma_ch *chdat)
{
	u32		reg = musb_readl(chdat->tbase, TUSB_DMA_EP_MAP);
	int		i, dmareq_nr = -1;

	const int sync_dev[6] = {
		OMAP24XX_DMA_EXT_DMAREQ0,
		OMAP24XX_DMA_EXT_DMAREQ1,
		OMAP242X_DMA_EXT_DMAREQ2,
		OMAP242X_DMA_EXT_DMAREQ3,
		OMAP242X_DMA_EXT_DMAREQ4,
		OMAP242X_DMA_EXT_DMAREQ5,
	};

	for (i = 0; i < MAX_DMAREQ; i++) {
		int cur = (reg & (0xf << (i * 5))) >> (i * 5);
		if (cur == 0) {
			dmareq_nr = i;
			break;
		}
	}

	if (dmareq_nr == -1)
		return -EAGAIN;

	reg |= (chdat->epnum << (dmareq_nr * 5));
	if (chdat->tx)
		reg |= ((1 << 4) << (dmareq_nr * 5));
	musb_writel(chdat->tbase, TUSB_DMA_EP_MAP, reg);

	chdat->dmareq = dmareq_nr;
	chdat->sync_dev = sync_dev[chdat->dmareq];

	return 0;
}

static inline void tusb_omap_dma_free_dmareq(struct tusb_omap_dma_ch *chdat)
{
	u32 reg;

	if (!chdat || chdat->dmareq < 0)
		return;

	reg = musb_readl(chdat->tbase, TUSB_DMA_EP_MAP);
	reg &= ~(0x1f << (chdat->dmareq * 5));
	musb_writel(chdat->tbase, TUSB_DMA_EP_MAP, reg);

	chdat->dmareq = -1;
	chdat->sync_dev = -1;
}

static struct dma_channel *dma_channel_pool[MAX_DMAREQ];

static struct dma_channel *
tusb_omap_dma_allocate(struct dma_controller *c,
		struct musb_hw_ep *hw_ep,
		u8 tx)
{
	int ret, i;
	const char		*dev_name;
	struct tusb_omap_dma	*tusb_dma;
	struct musb		*musb;
	void __iomem		*tbase;
	struct dma_channel	*channel = NULL;
	struct tusb_omap_dma_ch	*chdat = NULL;
	u32			reg;

	tusb_dma = container_of(c, struct tusb_omap_dma, controller);
	musb = tusb_dma->musb;
	tbase = musb->ctrl_base;

	reg = musb_readl(tbase, TUSB_DMA_INT_MASK);
	if (tx)
		reg &= ~(1 << hw_ep->epnum);
	else
		reg &= ~(1 << (hw_ep->epnum + 15));
	musb_writel(tbase, TUSB_DMA_INT_MASK, reg);

	/* REVISIT: Why does dmareq5 not work? */
	if (hw_ep->epnum == 0) {
		dev_dbg(musb->controller, "Not allowing DMA for ep0 %s\n", tx ? "tx" : "rx");
		return NULL;
	}

	for (i = 0; i < MAX_DMAREQ; i++) {
		struct dma_channel *ch = dma_channel_pool[i];
		if (ch->status == MUSB_DMA_STATUS_UNKNOWN) {
			ch->status = MUSB_DMA_STATUS_FREE;
			channel = ch;
			chdat = ch->private_data;
			break;
		}
	}

	if (!channel)
		return NULL;

	if (tx) {
		chdat->tx = 1;
		dev_name = "TUSB transmit";
	} else {
		chdat->tx = 0;
		dev_name = "TUSB receive";
	}

	chdat->musb = tusb_dma->musb;
	chdat->tbase = tusb_dma->tbase;
	chdat->hw_ep = hw_ep;
	chdat->epnum = hw_ep->epnum;
	chdat->dmareq = -1;
	chdat->completed_len = 0;
	chdat->tusb_dma = tusb_dma;

	channel->max_len = 0x7fffffff;
	channel->desired_mode = 0;
	channel->actual_len = 0;

	if (tusb_dma->multichannel) {
		ret = tusb_omap_dma_allocate_dmareq(chdat);
		if (ret != 0)
			goto free_dmareq;

		ret = omap_request_dma(chdat->sync_dev, dev_name,
				tusb_omap_dma_cb, channel, &chdat->ch);
		if (ret != 0)
			goto free_dmareq;
	} else if (tusb_dma->ch == -1) {
		tusb_dma->dmareq = 0;
		tusb_dma->sync_dev = OMAP24XX_DMA_EXT_DMAREQ0;

		/* Callback data gets set later in the shared dmareq case */
		ret = omap_request_dma(tusb_dma->sync_dev, "TUSB shared",
				tusb_omap_dma_cb, NULL, &tusb_dma->ch);
		if (ret != 0)
			goto free_dmareq;

		chdat->dmareq = -1;
		chdat->ch = -1;
	}

	dev_dbg(musb->controller, "ep%i %s dma: %s dma%i dmareq%i sync%i\n",
		chdat->epnum,
		chdat->tx ? "tx" : "rx",
		chdat->ch >= 0 ? "dedicated" : "shared",
		chdat->ch >= 0 ? chdat->ch : tusb_dma->ch,
		chdat->dmareq >= 0 ? chdat->dmareq : tusb_dma->dmareq,
		chdat->sync_dev >= 0 ? chdat->sync_dev : tusb_dma->sync_dev);

	return channel;

free_dmareq:
	tusb_omap_dma_free_dmareq(chdat);

	dev_dbg(musb->controller, "ep%i: Could not get a DMA channel\n", chdat->epnum);
	channel->status = MUSB_DMA_STATUS_UNKNOWN;

	return NULL;
}

static void tusb_omap_dma_release(struct dma_channel *channel)
{
	struct tusb_omap_dma_ch	*chdat = to_chdat(channel);
	struct musb		*musb = chdat->musb;
	void __iomem		*tbase = musb->ctrl_base;
	u32			reg;

	dev_dbg(musb->controller, "ep%i ch%i\n", chdat->epnum, chdat->ch);

	reg = musb_readl(tbase, TUSB_DMA_INT_MASK);
	if (chdat->tx)
		reg |= (1 << chdat->epnum);
	else
		reg |= (1 << (chdat->epnum + 15));
	musb_writel(tbase, TUSB_DMA_INT_MASK, reg);

	reg = musb_readl(tbase, TUSB_DMA_INT_CLEAR);
	if (chdat->tx)
		reg |= (1 << chdat->epnum);
	else
		reg |= (1 << (chdat->epnum + 15));
	musb_writel(tbase, TUSB_DMA_INT_CLEAR, reg);

	channel->status = MUSB_DMA_STATUS_UNKNOWN;

	if (chdat->ch >= 0) {
		omap_stop_dma(chdat->ch);
		omap_free_dma(chdat->ch);
		chdat->ch = -1;
	}

	if (chdat->dmareq >= 0)
		tusb_omap_dma_free_dmareq(chdat);

	channel = NULL;
}

void dma_controller_destroy(struct dma_controller *c)
{
	struct tusb_omap_dma	*tusb_dma;
	int			i;

	tusb_dma = container_of(c, struct tusb_omap_dma, controller);
	for (i = 0; i < MAX_DMAREQ; i++) {
		struct dma_channel *ch = dma_channel_pool[i];
		if (ch) {
			kfree(ch->private_data);
			kfree(ch);
		}
	}

	if (tusb_dma && !tusb_dma->multichannel && tusb_dma->ch >= 0)
		omap_free_dma(tusb_dma->ch);

	kfree(tusb_dma);
}

struct dma_controller *dma_controller_create(struct musb *musb, void __iomem *base)
{
	void __iomem		*tbase = musb->ctrl_base;
	struct tusb_omap_dma	*tusb_dma;
	int			i;

	/* REVISIT: Get dmareq lines used from board-*.c */

	musb_writel(musb->ctrl_base, TUSB_DMA_INT_MASK, 0x7fffffff);
	musb_writel(musb->ctrl_base, TUSB_DMA_EP_MAP, 0);

	musb_writel(tbase, TUSB_DMA_REQ_CONF,
		TUSB_DMA_REQ_CONF_BURST_SIZE(2)
		| TUSB_DMA_REQ_CONF_DMA_REQ_EN(0x3f)
		| TUSB_DMA_REQ_CONF_DMA_REQ_ASSER(2));

	tusb_dma = kzalloc(sizeof(struct tusb_omap_dma), GFP_KERNEL);
	if (!tusb_dma)
		goto out;

	tusb_dma->musb = musb;
	tusb_dma->tbase = musb->ctrl_base;

	tusb_dma->ch = -1;
	tusb_dma->dmareq = -1;
	tusb_dma->sync_dev = -1;

	tusb_dma->controller.channel_alloc = tusb_omap_dma_allocate;
	tusb_dma->controller.channel_release = tusb_omap_dma_release;
	tusb_dma->controller.channel_program = tusb_omap_dma_program;
	tusb_dma->controller.channel_abort = tusb_omap_dma_abort;

	if (musb->tusb_revision >= TUSB_REV_30)
		tusb_dma->multichannel = 1;

	for (i = 0; i < MAX_DMAREQ; i++) {
		struct dma_channel	*ch;
		struct tusb_omap_dma_ch	*chdat;

		ch = kzalloc(sizeof(struct dma_channel), GFP_KERNEL);
		if (!ch)
			goto cleanup;

		dma_channel_pool[i] = ch;

		chdat = kzalloc(sizeof(struct tusb_omap_dma_ch), GFP_KERNEL);
		if (!chdat)
			goto cleanup;

		ch->status = MUSB_DMA_STATUS_UNKNOWN;
		ch->private_data = chdat;
	}

	return &tusb_dma->controller;

cleanup:
	dma_controller_destroy(&tusb_dma->controller);
out:
	return NULL;
}