cx18-alsa-pcm.c

  1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 *  ALSA PCM device for the
  4 *  ALSA interface to cx18 PCM capture streams
  5 *
  6 *  Copyright (C) 2009  Andy Walls <awalls@md.metrocast.net>
  7 *  Copyright (C) 2009  Devin Heitmueller <dheitmueller@kernellabs.com>
  8 *
  9 *  Portions of this work were sponsored by ONELAN Limited.
 10 */
 11
 12#include <linux/init.h>
 13#include <linux/kernel.h>
 14
 15#include <media/v4l2-device.h>
 16
 17#include <sound/core.h>
 18#include <sound/pcm.h>
 19
 20#include "cx18-driver.h"
 21#include "cx18-queue.h"
 22#include "cx18-streams.h"
 23#include "cx18-fileops.h"
 24#include "cx18-alsa.h"
 25#include "cx18-alsa-pcm.h"
 26
 27static unsigned int pcm_debug;
 28module_param(pcm_debug, int, 0644);
 29MODULE_PARM_DESC(pcm_debug, "enable debug messages for pcm");
 30
 31#define dprintk(fmt, arg...) do {					\
 32	    if (pcm_debug)						\
 33		printk(KERN_INFO "cx18-alsa-pcm %s: " fmt,		\
 34				  __func__, ##arg);			\
 35	} while (0)
 36
 37static const struct snd_pcm_hardware snd_cx18_hw_capture = {
 38	.info = SNDRV_PCM_INFO_BLOCK_TRANSFER |
 39		SNDRV_PCM_INFO_MMAP           |
 40		SNDRV_PCM_INFO_INTERLEAVED    |
 41		SNDRV_PCM_INFO_MMAP_VALID,
 42
 43	.formats = SNDRV_PCM_FMTBIT_S16_LE,
 44
 45	.rates = SNDRV_PCM_RATE_48000,
 46
 47	.rate_min = 48000,
 48	.rate_max = 48000,
 49	.channels_min = 2,
 50	.channels_max = 2,
 51	.buffer_bytes_max = 62720 * 8,	/* just about the value in usbaudio.c */
 52	.period_bytes_min = 64,		/* 12544/2, */
 53	.period_bytes_max = 12544,
 54	.periods_min = 2,
 55	.periods_max = 98,		/* 12544, */
 56};
 57
 58void cx18_alsa_announce_pcm_data(struct snd_cx18_card *cxsc, u8 *pcm_data,
 59				 size_t num_bytes)
 60{
 61	struct snd_pcm_substream *substream;
 62	struct snd_pcm_runtime *runtime;
 63	unsigned int oldptr;
 64	unsigned int stride;
 65	int period_elapsed = 0;
 66	int length;
 67
 68	dprintk("cx18 alsa announce ptr=%p data=%p num_bytes=%zu\n", cxsc,
 69		pcm_data, num_bytes);
 70
 71	substream = cxsc->capture_pcm_substream;
 72	if (substream == NULL) {
 73		dprintk("substream was NULL\n");
 74		return;
 75	}
 76
 77	runtime = substream->runtime;
 78	if (runtime == NULL) {
 79		dprintk("runtime was NULL\n");
 80		return;
 81	}
 82
 83	stride = runtime->frame_bits >> 3;
 84	if (stride == 0) {
 85		dprintk("stride is zero\n");
 86		return;
 87	}
 88
 89	length = num_bytes / stride;
 90	if (length == 0) {
 91		dprintk("%s: length was zero\n", __func__);
 92		return;
 93	}
 94
 95	if (runtime->dma_area == NULL) {
 96		dprintk("dma area was NULL - ignoring\n");
 97		return;
 98	}
 99
100	oldptr = cxsc->hwptr_done_capture;
101	if (oldptr + length >= runtime->buffer_size) {
102		unsigned int cnt =
103			runtime->buffer_size - oldptr;
104		memcpy(runtime->dma_area + oldptr * stride, pcm_data,
105		       cnt * stride);
106		memcpy(runtime->dma_area, pcm_data + cnt * stride,
107		       length * stride - cnt * stride);
108	} else {
109		memcpy(runtime->dma_area + oldptr * stride, pcm_data,
110		       length * stride);
111	}
112	snd_pcm_stream_lock(substream);
113
114	cxsc->hwptr_done_capture += length;
115	if (cxsc->hwptr_done_capture >=
116	    runtime->buffer_size)
117		cxsc->hwptr_done_capture -=
118			runtime->buffer_size;
119
120	cxsc->capture_transfer_done += length;
121	if (cxsc->capture_transfer_done >=
122	    runtime->period_size) {
123		cxsc->capture_transfer_done -=
124			runtime->period_size;
125		period_elapsed = 1;
126	}
127
128	snd_pcm_stream_unlock(substream);
129
130	if (period_elapsed)
131		snd_pcm_period_elapsed(substream);
132}
133
134static int snd_cx18_pcm_capture_open(struct snd_pcm_substream *substream)
135{
136	struct snd_cx18_card *cxsc = snd_pcm_substream_chip(substream);
137	struct snd_pcm_runtime *runtime = substream->runtime;
138	struct v4l2_device *v4l2_dev = cxsc->v4l2_dev;
139	struct cx18 *cx = to_cx18(v4l2_dev);
140	struct cx18_stream *s;
141	struct cx18_open_id item;
142	int ret;
143
144	/* Instruct the cx18 to start sending packets */
145	snd_cx18_lock(cxsc);
146	s = &cx->streams[CX18_ENC_STREAM_TYPE_PCM];
147
148	item.cx = cx;
149	item.type = s->type;
150	item.open_id = cx->open_id++;
151
152	/* See if the stream is available */
153	if (cx18_claim_stream(&item, item.type)) {
154		/* No, it's already in use */
155		snd_cx18_unlock(cxsc);
156		return -EBUSY;
157	}
158
159	if (test_bit(CX18_F_S_STREAMOFF, &s->s_flags) ||
160	    test_and_set_bit(CX18_F_S_STREAMING, &s->s_flags)) {
161		/* We're already streaming.  No additional action required */
162		snd_cx18_unlock(cxsc);
163		return 0;
164	}
165
166
167	runtime->hw = snd_cx18_hw_capture;
168	snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS);
169	cxsc->capture_pcm_substream = substream;
170	runtime->private_data = cx;
171
172	cx->pcm_announce_callback = cx18_alsa_announce_pcm_data;
173
174	/* Not currently streaming, so start it up */
175	set_bit(CX18_F_S_STREAMING, &s->s_flags);
176	ret = cx18_start_v4l2_encode_stream(s);
177	snd_cx18_unlock(cxsc);
178
179	return ret;
180}
181
182static int snd_cx18_pcm_capture_close(struct snd_pcm_substream *substream)
183{
184	struct snd_cx18_card *cxsc = snd_pcm_substream_chip(substream);
185	struct v4l2_device *v4l2_dev = cxsc->v4l2_dev;
186	struct cx18 *cx = to_cx18(v4l2_dev);
187	struct cx18_stream *s;
188
189	/* Instruct the cx18 to stop sending packets */
190	snd_cx18_lock(cxsc);
191	s = &cx->streams[CX18_ENC_STREAM_TYPE_PCM];
192	cx18_stop_v4l2_encode_stream(s, 0);
193	clear_bit(CX18_F_S_STREAMING, &s->s_flags);
194
195	cx18_release_stream(s);
196
197	cx->pcm_announce_callback = NULL;
198	snd_cx18_unlock(cxsc);
199
200	return 0;
201}
202
203static int snd_cx18_pcm_prepare(struct snd_pcm_substream *substream)
204{
205	struct snd_cx18_card *cxsc = snd_pcm_substream_chip(substream);
206
207	cxsc->hwptr_done_capture = 0;
208	cxsc->capture_transfer_done = 0;
209
210	return 0;
211}
212
213static int snd_cx18_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
214{
215	return 0;
216}
217
218static
219snd_pcm_uframes_t snd_cx18_pcm_pointer(struct snd_pcm_substream *substream)
220{
221	unsigned long flags;
222	snd_pcm_uframes_t hwptr_done;
223	struct snd_cx18_card *cxsc = snd_pcm_substream_chip(substream);
224
225	spin_lock_irqsave(&cxsc->slock, flags);
226	hwptr_done = cxsc->hwptr_done_capture;
227	spin_unlock_irqrestore(&cxsc->slock, flags);
228
229	return hwptr_done;
230}
231
232static const struct snd_pcm_ops snd_cx18_pcm_capture_ops = {
233	.open		= snd_cx18_pcm_capture_open,
234	.close		= snd_cx18_pcm_capture_close,
235	.prepare	= snd_cx18_pcm_prepare,
236	.trigger	= snd_cx18_pcm_trigger,
237	.pointer	= snd_cx18_pcm_pointer,
238};
239
240int snd_cx18_pcm_create(struct snd_cx18_card *cxsc)
241{
242	struct snd_pcm *sp;
243	struct snd_card *sc = cxsc->sc;
244	struct v4l2_device *v4l2_dev = cxsc->v4l2_dev;
245	struct cx18 *cx = to_cx18(v4l2_dev);
246	int ret;
247
248	ret = snd_pcm_new(sc, "CX23418 PCM",
249			  0, /* PCM device 0, the only one for this card */
250			  0, /* 0 playback substreams */
251			  1, /* 1 capture substream */
252			  &sp);
253	if (ret) {
254		CX18_ALSA_ERR("%s: snd_cx18_pcm_create() failed with err %d\n",
255			      __func__, ret);
256		goto err_exit;
257	}
258
259	spin_lock_init(&cxsc->slock);
260
261	snd_pcm_set_ops(sp, SNDRV_PCM_STREAM_CAPTURE,
262			&snd_cx18_pcm_capture_ops);
263	snd_pcm_set_managed_buffer_all(sp, SNDRV_DMA_TYPE_VMALLOC, NULL, 0, 0);
264	sp->info_flags = 0;
265	sp->private_data = cxsc;
266	strscpy(sp->name, cx->card_name, sizeof(sp->name));
267
268	return 0;
269
270err_exit:
271	return ret;
272}