xref: /linux/drivers/media/pci/cx18/cx18-alsa-pcm.c (revision 8dd06ef34b6e2f41b29fbf5fc1663780f2524285)
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 
27 static unsigned int pcm_debug;
28 module_param(pcm_debug, int, 0644);
29 MODULE_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 
37 static 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 
cx18_alsa_announce_pcm_data(struct snd_cx18_card * cxsc,u8 * pcm_data,size_t num_bytes)58 void 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 
snd_cx18_pcm_capture_open(struct snd_pcm_substream * substream)134 static 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 
snd_cx18_pcm_capture_close(struct snd_pcm_substream * substream)182 static 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 
snd_cx18_pcm_prepare(struct snd_pcm_substream * substream)203 static 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 
snd_cx18_pcm_trigger(struct snd_pcm_substream * substream,int cmd)213 static int snd_cx18_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
214 {
215 	return 0;
216 }
217 
218 static
snd_cx18_pcm_pointer(struct snd_pcm_substream * substream)219 snd_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 
232 static 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 
snd_cx18_pcm_create(struct snd_cx18_card * cxsc)240 int 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 
270 err_exit:
271 	return ret;
272 }
273