Free Electrons

Embedded Linux Experts

  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
/*
 * Linux driver for M2Tech hiFace compatible devices
 *
 * Copyright 2012-2013 (C) M2TECH S.r.l and Amarula Solutions B.V.
 *
 * Authors:  Michael Trimarchi <michael@amarulasolutions.com>
 *           Antonio Ospite <ao2@amarulasolutions.com>
 *
 * The driver is based on the work done in TerraTec DMX 6Fire USB
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 */

#include <linux/slab.h>
#include <sound/pcm.h>

#include "pcm.h"
#include "chip.h"

#define OUT_EP          0x2
#define PCM_N_URBS      8
#define PCM_PACKET_SIZE 4096
#define PCM_BUFFER_SIZE (2 * PCM_N_URBS * PCM_PACKET_SIZE)

struct pcm_urb {
	struct hiface_chip *chip;

	struct urb instance;
	struct usb_anchor submitted;
	u8 *buffer;
};

struct pcm_substream {
	spinlock_t lock;
	struct snd_pcm_substream *instance;

	bool active;
	snd_pcm_uframes_t dma_off;    /* current position in alsa dma_area */
	snd_pcm_uframes_t period_off; /* current position in current period */
};

enum { /* pcm streaming states */
	STREAM_DISABLED, /* no pcm streaming */
	STREAM_STARTING, /* pcm streaming requested, waiting to become ready */
	STREAM_RUNNING,  /* pcm streaming running */
	STREAM_STOPPING
};

struct pcm_runtime {
	struct hiface_chip *chip;
	struct snd_pcm *instance;

	struct pcm_substream playback;
	bool panic; /* if set driver won't do anymore pcm on device */

	struct pcm_urb out_urbs[PCM_N_URBS];

	struct mutex stream_mutex;
	u8 stream_state; /* one of STREAM_XXX */
	u8 extra_freq;
	wait_queue_head_t stream_wait_queue;
	bool stream_wait_cond;
};

static const unsigned int rates[] = { 44100, 48000, 88200, 96000, 176400, 192000,
				      352800, 384000 };
static const struct snd_pcm_hw_constraint_list constraints_extra_rates = {
	.count = ARRAY_SIZE(rates),
	.list = rates,
	.mask = 0,
};

static const struct snd_pcm_hardware pcm_hw = {
	.info = SNDRV_PCM_INFO_MMAP |
		SNDRV_PCM_INFO_INTERLEAVED |
		SNDRV_PCM_INFO_BLOCK_TRANSFER |
		SNDRV_PCM_INFO_PAUSE |
		SNDRV_PCM_INFO_MMAP_VALID |
		SNDRV_PCM_INFO_BATCH,

	.formats = SNDRV_PCM_FMTBIT_S32_LE,

	.rates = SNDRV_PCM_RATE_44100 |
		SNDRV_PCM_RATE_48000 |
		SNDRV_PCM_RATE_88200 |
		SNDRV_PCM_RATE_96000 |
		SNDRV_PCM_RATE_176400 |
		SNDRV_PCM_RATE_192000,

	.rate_min = 44100,
	.rate_max = 192000, /* changes in hiface_pcm_open to support extra rates */
	.channels_min = 2,
	.channels_max = 2,
	.buffer_bytes_max = PCM_BUFFER_SIZE,
	.period_bytes_min = PCM_PACKET_SIZE,
	.period_bytes_max = PCM_BUFFER_SIZE,
	.periods_min = 2,
	.periods_max = 1024
};

/* message values used to change the sample rate */
#define HIFACE_SET_RATE_REQUEST 0xb0

#define HIFACE_RATE_44100  0x43
#define HIFACE_RATE_48000  0x4b
#define HIFACE_RATE_88200  0x42
#define HIFACE_RATE_96000  0x4a
#define HIFACE_RATE_176400 0x40
#define HIFACE_RATE_192000 0x48
#define HIFACE_RATE_352800 0x58
#define HIFACE_RATE_384000 0x68

static int hiface_pcm_set_rate(struct pcm_runtime *rt, unsigned int rate)
{
	struct usb_device *device = rt->chip->dev;
	u16 rate_value;
	int ret;

	/* We are already sure that the rate is supported here thanks to
	 * ALSA constraints
	 */
	switch (rate) {
	case 44100:
		rate_value = HIFACE_RATE_44100;
		break;
	case 48000:
		rate_value = HIFACE_RATE_48000;
		break;
	case 88200:
		rate_value = HIFACE_RATE_88200;
		break;
	case 96000:
		rate_value = HIFACE_RATE_96000;
		break;
	case 176400:
		rate_value = HIFACE_RATE_176400;
		break;
	case 192000:
		rate_value = HIFACE_RATE_192000;
		break;
	case 352800:
		rate_value = HIFACE_RATE_352800;
		break;
	case 384000:
		rate_value = HIFACE_RATE_384000;
		break;
	default:
		dev_err(&device->dev, "Unsupported rate %d\n", rate);
		return -EINVAL;
	}

	/*
	 * USBIO: Vendor 0xb0(wValue=0x0043, wIndex=0x0000)
	 * 43 b0 43 00 00 00 00 00
	 * USBIO: Vendor 0xb0(wValue=0x004b, wIndex=0x0000)
	 * 43 b0 4b 00 00 00 00 00
	 * This control message doesn't have any ack from the
	 * other side
	 */
	ret = usb_control_msg(device, usb_sndctrlpipe(device, 0),
			      HIFACE_SET_RATE_REQUEST,
			      USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_OTHER,
			      rate_value, 0, NULL, 0, 100);
	if (ret < 0) {
		dev_err(&device->dev, "Error setting samplerate %d.\n", rate);
		return ret;
	}

	return 0;
}

static struct pcm_substream *hiface_pcm_get_substream(struct snd_pcm_substream
						      *alsa_sub)
{
	struct pcm_runtime *rt = snd_pcm_substream_chip(alsa_sub);
	struct device *device = &rt->chip->dev->dev;

	if (alsa_sub->stream == SNDRV_PCM_STREAM_PLAYBACK)
		return &rt->playback;

	dev_err(device, "Error getting pcm substream slot.\n");
	return NULL;
}

/* call with stream_mutex locked */
static void hiface_pcm_stream_stop(struct pcm_runtime *rt)
{
	int i, time;

	if (rt->stream_state != STREAM_DISABLED) {
		rt->stream_state = STREAM_STOPPING;

		for (i = 0; i < PCM_N_URBS; i++) {
			time = usb_wait_anchor_empty_timeout(
					&rt->out_urbs[i].submitted, 100);
			if (!time)
				usb_kill_anchored_urbs(
					&rt->out_urbs[i].submitted);
			usb_kill_urb(&rt->out_urbs[i].instance);
		}

		rt->stream_state = STREAM_DISABLED;
	}
}

/* call with stream_mutex locked */
static int hiface_pcm_stream_start(struct pcm_runtime *rt)
{
	int ret = 0;
	int i;

	if (rt->stream_state == STREAM_DISABLED) {

		/* reset panic state when starting a new stream */
		rt->panic = false;

		/* submit our out urbs zero init */
		rt->stream_state = STREAM_STARTING;
		for (i = 0; i < PCM_N_URBS; i++) {
			memset(rt->out_urbs[i].buffer, 0, PCM_PACKET_SIZE);
			usb_anchor_urb(&rt->out_urbs[i].instance,
				       &rt->out_urbs[i].submitted);
			ret = usb_submit_urb(&rt->out_urbs[i].instance,
					     GFP_ATOMIC);
			if (ret) {
				hiface_pcm_stream_stop(rt);
				return ret;
			}
		}

		/* wait for first out urb to return (sent in in urb handler) */
		wait_event_timeout(rt->stream_wait_queue, rt->stream_wait_cond,
				   HZ);
		if (rt->stream_wait_cond) {
			struct device *device = &rt->chip->dev->dev;
			dev_dbg(device, "%s: Stream is running wakeup event\n",
				 __func__);
			rt->stream_state = STREAM_RUNNING;
		} else {
			hiface_pcm_stream_stop(rt);
			return -EIO;
		}
	}
	return ret;
}

/* The hardware wants word-swapped 32-bit values */
static void memcpy_swahw32(u8 *dest, u8 *src, unsigned int n)
{
	unsigned int i;

	for (i = 0; i < n / 4; i++)
		((u32 *)dest)[i] = swahw32(((u32 *)src)[i]);
}

/* call with substream locked */
/* returns true if a period elapsed */
static bool hiface_pcm_playback(struct pcm_substream *sub, struct pcm_urb *urb)
{
	struct snd_pcm_runtime *alsa_rt = sub->instance->runtime;
	struct device *device = &urb->chip->dev->dev;
	u8 *source;
	unsigned int pcm_buffer_size;

	WARN_ON(alsa_rt->format != SNDRV_PCM_FORMAT_S32_LE);

	pcm_buffer_size = snd_pcm_lib_buffer_bytes(sub->instance);

	if (sub->dma_off + PCM_PACKET_SIZE <= pcm_buffer_size) {
		dev_dbg(device, "%s: (1) buffer_size %#x dma_offset %#x\n", __func__,
			 (unsigned int) pcm_buffer_size,
			 (unsigned int) sub->dma_off);

		source = alsa_rt->dma_area + sub->dma_off;
		memcpy_swahw32(urb->buffer, source, PCM_PACKET_SIZE);
	} else {
		/* wrap around at end of ring buffer */
		unsigned int len;

		dev_dbg(device, "%s: (2) buffer_size %#x dma_offset %#x\n", __func__,
			 (unsigned int) pcm_buffer_size,
			 (unsigned int) sub->dma_off);

		len = pcm_buffer_size - sub->dma_off;

		source = alsa_rt->dma_area + sub->dma_off;
		memcpy_swahw32(urb->buffer, source, len);

		source = alsa_rt->dma_area;
		memcpy_swahw32(urb->buffer + len, source,
			       PCM_PACKET_SIZE - len);
	}
	sub->dma_off += PCM_PACKET_SIZE;
	if (sub->dma_off >= pcm_buffer_size)
		sub->dma_off -= pcm_buffer_size;

	sub->period_off += PCM_PACKET_SIZE;
	if (sub->period_off >= alsa_rt->period_size) {
		sub->period_off %= alsa_rt->period_size;
		return true;
	}
	return false;
}

static void hiface_pcm_out_urb_handler(struct urb *usb_urb)
{
	struct pcm_urb *out_urb = usb_urb->context;
	struct pcm_runtime *rt = out_urb->chip->pcm;
	struct pcm_substream *sub;
	bool do_period_elapsed = false;
	unsigned long flags;
	int ret;

	if (rt->panic || rt->stream_state == STREAM_STOPPING)
		return;

	if (unlikely(usb_urb->status == -ENOENT ||	/* unlinked */
		     usb_urb->status == -ENODEV ||	/* device removed */
		     usb_urb->status == -ECONNRESET ||	/* unlinked */
		     usb_urb->status == -ESHUTDOWN)) {	/* device disabled */
		goto out_fail;
	}

	if (rt->stream_state == STREAM_STARTING) {
		rt->stream_wait_cond = true;
		wake_up(&rt->stream_wait_queue);
	}

	/* now send our playback data (if a free out urb was found) */
	sub = &rt->playback;
	spin_lock_irqsave(&sub->lock, flags);
	if (sub->active)
		do_period_elapsed = hiface_pcm_playback(sub, out_urb);
	else
		memset(out_urb->buffer, 0, PCM_PACKET_SIZE);

	spin_unlock_irqrestore(&sub->lock, flags);

	if (do_period_elapsed)
		snd_pcm_period_elapsed(sub->instance);

	ret = usb_submit_urb(&out_urb->instance, GFP_ATOMIC);
	if (ret < 0)
		goto out_fail;

	return;

out_fail:
	rt->panic = true;
}

static int hiface_pcm_open(struct snd_pcm_substream *alsa_sub)
{
	struct pcm_runtime *rt = snd_pcm_substream_chip(alsa_sub);
	struct pcm_substream *sub = NULL;
	struct snd_pcm_runtime *alsa_rt = alsa_sub->runtime;
	int ret;

	if (rt->panic)
		return -EPIPE;

	mutex_lock(&rt->stream_mutex);
	alsa_rt->hw = pcm_hw;

	if (alsa_sub->stream == SNDRV_PCM_STREAM_PLAYBACK)
		sub = &rt->playback;

	if (!sub) {
		struct device *device = &rt->chip->dev->dev;
		mutex_unlock(&rt->stream_mutex);
		dev_err(device, "Invalid stream type\n");
		return -EINVAL;
	}

	if (rt->extra_freq) {
		alsa_rt->hw.rates |= SNDRV_PCM_RATE_KNOT;
		alsa_rt->hw.rate_max = 384000;

		/* explicit constraints needed as we added SNDRV_PCM_RATE_KNOT */
		ret = snd_pcm_hw_constraint_list(alsa_sub->runtime, 0,
						 SNDRV_PCM_HW_PARAM_RATE,
						 &constraints_extra_rates);
		if (ret < 0) {
			mutex_unlock(&rt->stream_mutex);
			return ret;
		}
	}

	sub->instance = alsa_sub;
	sub->active = false;
	mutex_unlock(&rt->stream_mutex);
	return 0;
}

static int hiface_pcm_close(struct snd_pcm_substream *alsa_sub)
{
	struct pcm_runtime *rt = snd_pcm_substream_chip(alsa_sub);
	struct pcm_substream *sub = hiface_pcm_get_substream(alsa_sub);
	unsigned long flags;

	if (rt->panic)
		return 0;

	mutex_lock(&rt->stream_mutex);
	if (sub) {
		hiface_pcm_stream_stop(rt);

		/* deactivate substream */
		spin_lock_irqsave(&sub->lock, flags);
		sub->instance = NULL;
		sub->active = false;
		spin_unlock_irqrestore(&sub->lock, flags);

	}
	mutex_unlock(&rt->stream_mutex);
	return 0;
}

static int hiface_pcm_hw_params(struct snd_pcm_substream *alsa_sub,
				struct snd_pcm_hw_params *hw_params)
{
	return snd_pcm_lib_alloc_vmalloc_buffer(alsa_sub,
						params_buffer_bytes(hw_params));
}

static int hiface_pcm_hw_free(struct snd_pcm_substream *alsa_sub)
{
	return snd_pcm_lib_free_vmalloc_buffer(alsa_sub);
}

static int hiface_pcm_prepare(struct snd_pcm_substream *alsa_sub)
{
	struct pcm_runtime *rt = snd_pcm_substream_chip(alsa_sub);
	struct pcm_substream *sub = hiface_pcm_get_substream(alsa_sub);
	struct snd_pcm_runtime *alsa_rt = alsa_sub->runtime;
	int ret;

	if (rt->panic)
		return -EPIPE;
	if (!sub)
		return -ENODEV;

	mutex_lock(&rt->stream_mutex);

	hiface_pcm_stream_stop(rt);

	sub->dma_off = 0;
	sub->period_off = 0;

	if (rt->stream_state == STREAM_DISABLED) {

		ret = hiface_pcm_set_rate(rt, alsa_rt->rate);
		if (ret) {
			mutex_unlock(&rt->stream_mutex);
			return ret;
		}
		ret = hiface_pcm_stream_start(rt);
		if (ret) {
			mutex_unlock(&rt->stream_mutex);
			return ret;
		}
	}
	mutex_unlock(&rt->stream_mutex);
	return 0;
}

static int hiface_pcm_trigger(struct snd_pcm_substream *alsa_sub, int cmd)
{
	struct pcm_substream *sub = hiface_pcm_get_substream(alsa_sub);
	struct pcm_runtime *rt = snd_pcm_substream_chip(alsa_sub);

	if (rt->panic)
		return -EPIPE;
	if (!sub)
		return -ENODEV;

	switch (cmd) {
	case SNDRV_PCM_TRIGGER_START:
	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
		spin_lock_irq(&sub->lock);
		sub->active = true;
		spin_unlock_irq(&sub->lock);
		return 0;

	case SNDRV_PCM_TRIGGER_STOP:
	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
		spin_lock_irq(&sub->lock);
		sub->active = false;
		spin_unlock_irq(&sub->lock);
		return 0;

	default:
		return -EINVAL;
	}
}

static snd_pcm_uframes_t hiface_pcm_pointer(struct snd_pcm_substream *alsa_sub)
{
	struct pcm_substream *sub = hiface_pcm_get_substream(alsa_sub);
	struct pcm_runtime *rt = snd_pcm_substream_chip(alsa_sub);
	unsigned long flags;
	snd_pcm_uframes_t dma_offset;

	if (rt->panic || !sub)
		return SNDRV_PCM_POS_XRUN;

	spin_lock_irqsave(&sub->lock, flags);
	dma_offset = sub->dma_off;
	spin_unlock_irqrestore(&sub->lock, flags);
	return bytes_to_frames(alsa_sub->runtime, dma_offset);
}

static struct snd_pcm_ops pcm_ops = {
	.open = hiface_pcm_open,
	.close = hiface_pcm_close,
	.ioctl = snd_pcm_lib_ioctl,
	.hw_params = hiface_pcm_hw_params,
	.hw_free = hiface_pcm_hw_free,
	.prepare = hiface_pcm_prepare,
	.trigger = hiface_pcm_trigger,
	.pointer = hiface_pcm_pointer,
	.page = snd_pcm_lib_get_vmalloc_page,
	.mmap = snd_pcm_lib_mmap_vmalloc,
};

static int hiface_pcm_init_urb(struct pcm_urb *urb,
			       struct hiface_chip *chip,
			       unsigned int ep,
			       void (*handler)(struct urb *))
{
	urb->chip = chip;
	usb_init_urb(&urb->instance);

	urb->buffer = kzalloc(PCM_PACKET_SIZE, GFP_KERNEL);
	if (!urb->buffer)
		return -ENOMEM;

	usb_fill_bulk_urb(&urb->instance, chip->dev,
			  usb_sndbulkpipe(chip->dev, ep), (void *)urb->buffer,
			  PCM_PACKET_SIZE, handler, urb);
	init_usb_anchor(&urb->submitted);

	return 0;
}

void hiface_pcm_abort(struct hiface_chip *chip)
{
	struct pcm_runtime *rt = chip->pcm;

	if (rt) {
		rt->panic = true;

		mutex_lock(&rt->stream_mutex);
		hiface_pcm_stream_stop(rt);
		mutex_unlock(&rt->stream_mutex);
	}
}

static void hiface_pcm_destroy(struct hiface_chip *chip)
{
	struct pcm_runtime *rt = chip->pcm;
	int i;

	for (i = 0; i < PCM_N_URBS; i++)
		kfree(rt->out_urbs[i].buffer);

	kfree(chip->pcm);
	chip->pcm = NULL;
}

static void hiface_pcm_free(struct snd_pcm *pcm)
{
	struct pcm_runtime *rt = pcm->private_data;

	if (rt)
		hiface_pcm_destroy(rt->chip);
}

int hiface_pcm_init(struct hiface_chip *chip, u8 extra_freq)
{
	int i;
	int ret;
	struct snd_pcm *pcm;
	struct pcm_runtime *rt;

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

	rt->chip = chip;
	rt->stream_state = STREAM_DISABLED;
	if (extra_freq)
		rt->extra_freq = 1;

	init_waitqueue_head(&rt->stream_wait_queue);
	mutex_init(&rt->stream_mutex);
	spin_lock_init(&rt->playback.lock);

	for (i = 0; i < PCM_N_URBS; i++)
		hiface_pcm_init_urb(&rt->out_urbs[i], chip, OUT_EP,
				    hiface_pcm_out_urb_handler);

	ret = snd_pcm_new(chip->card, "USB-SPDIF Audio", 0, 1, 0, &pcm);
	if (ret < 0) {
		kfree(rt);
		dev_err(&chip->dev->dev, "Cannot create pcm instance\n");
		return ret;
	}

	pcm->private_data = rt;
	pcm->private_free = hiface_pcm_free;

	strlcpy(pcm->name, "USB-SPDIF Audio", sizeof(pcm->name));
	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &pcm_ops);

	rt->instance = pcm;

	chip->pcm = rt;
	return 0;
}