1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * u_uac1.c -- ALSA audio utilities for Gadget stack
4 *
5 * Copyright (C) 2008 Bryan Wu <cooloney@kernel.org>
6 * Copyright (C) 2008 Analog Devices, Inc
7 */
8
9 #include <linux/kernel.h>
10 #include <linux/module.h>
11 #include <linux/slab.h>
12 #include <linux/device.h>
13 #include <linux/delay.h>
14 #include <linux/ctype.h>
15 #include <linux/random.h>
16 #include <linux/syscalls.h>
17
18 #include "u_uac1_legacy.h"
19
20 /*
21 * This component encapsulates the ALSA devices for USB audio gadget
22 */
23
24 /*-------------------------------------------------------------------------*/
25
26 /*
27 * Some ALSA internal helper functions
28 */
snd_interval_refine_set(struct snd_interval * i,unsigned int val)29 static int snd_interval_refine_set(struct snd_interval *i, unsigned int val)
30 {
31 struct snd_interval t;
32 t.empty = 0;
33 t.min = t.max = val;
34 t.openmin = t.openmax = 0;
35 t.integer = 1;
36 return snd_interval_refine(i, &t);
37 }
38
_snd_pcm_hw_param_set(struct snd_pcm_hw_params * params,snd_pcm_hw_param_t var,unsigned int val,int dir)39 static int _snd_pcm_hw_param_set(struct snd_pcm_hw_params *params,
40 snd_pcm_hw_param_t var, unsigned int val,
41 int dir)
42 {
43 int changed;
44 if (hw_is_mask(var)) {
45 struct snd_mask *m = hw_param_mask(params, var);
46 if (val == 0 && dir < 0) {
47 changed = -EINVAL;
48 snd_mask_none(m);
49 } else {
50 if (dir > 0)
51 val++;
52 else if (dir < 0)
53 val--;
54 changed = snd_mask_refine_set(
55 hw_param_mask(params, var), val);
56 }
57 } else if (hw_is_interval(var)) {
58 struct snd_interval *i = hw_param_interval(params, var);
59 if (val == 0 && dir < 0) {
60 changed = -EINVAL;
61 snd_interval_none(i);
62 } else if (dir == 0)
63 changed = snd_interval_refine_set(i, val);
64 else {
65 struct snd_interval t;
66 t.openmin = 1;
67 t.openmax = 1;
68 t.empty = 0;
69 t.integer = 0;
70 if (dir < 0) {
71 t.min = val - 1;
72 t.max = val;
73 } else {
74 t.min = val;
75 t.max = val+1;
76 }
77 changed = snd_interval_refine(i, &t);
78 }
79 } else
80 return -EINVAL;
81 if (changed) {
82 params->cmask |= 1 << var;
83 params->rmask |= 1 << var;
84 }
85 return changed;
86 }
87 /*-------------------------------------------------------------------------*/
88
89 /*
90 * Set default hardware params
91 */
playback_default_hw_params(struct gaudio_snd_dev * snd)92 static int playback_default_hw_params(struct gaudio_snd_dev *snd)
93 {
94 struct snd_pcm_substream *substream = snd->substream;
95 struct snd_pcm_hw_params *params;
96 snd_pcm_sframes_t result;
97
98 /*
99 * SNDRV_PCM_ACCESS_RW_INTERLEAVED,
100 * SNDRV_PCM_FORMAT_S16_LE
101 * CHANNELS: 2
102 * RATE: 48000
103 */
104 snd->access = SNDRV_PCM_ACCESS_RW_INTERLEAVED;
105 snd->format = SNDRV_PCM_FORMAT_S16_LE;
106 snd->channels = 2;
107 snd->rate = 48000;
108
109 params = kzalloc(sizeof(*params), GFP_KERNEL);
110 if (!params)
111 return -ENOMEM;
112
113 _snd_pcm_hw_params_any(params);
114 _snd_pcm_hw_param_set(params, SNDRV_PCM_HW_PARAM_ACCESS,
115 snd->access, 0);
116 _snd_pcm_hw_param_set(params, SNDRV_PCM_HW_PARAM_FORMAT,
117 snd->format, 0);
118 _snd_pcm_hw_param_set(params, SNDRV_PCM_HW_PARAM_CHANNELS,
119 snd->channels, 0);
120 _snd_pcm_hw_param_set(params, SNDRV_PCM_HW_PARAM_RATE,
121 snd->rate, 0);
122
123 snd_pcm_kernel_ioctl(substream, SNDRV_PCM_IOCTL_DROP, NULL);
124 snd_pcm_kernel_ioctl(substream, SNDRV_PCM_IOCTL_HW_PARAMS, params);
125
126 result = snd_pcm_kernel_ioctl(substream, SNDRV_PCM_IOCTL_PREPARE, NULL);
127 if (result < 0) {
128 ERROR(snd->card,
129 "Preparing sound card failed: %d\n", (int)result);
130 kfree(params);
131 return result;
132 }
133
134 /* Store the hardware parameters */
135 snd->access = params_access(params);
136 snd->format = params_format(params);
137 snd->channels = params_channels(params);
138 snd->rate = params_rate(params);
139
140 kfree(params);
141
142 INFO(snd->card,
143 "Hardware params: access %x, format %x, channels %d, rate %d\n",
144 snd->access, snd->format, snd->channels, snd->rate);
145
146 return 0;
147 }
148
149 /*
150 * Playback audio buffer data by ALSA PCM device
151 */
u_audio_playback(struct gaudio * card,void * buf,size_t count)152 size_t u_audio_playback(struct gaudio *card, void *buf, size_t count)
153 {
154 struct gaudio_snd_dev *snd = &card->playback;
155 struct snd_pcm_substream *substream = snd->substream;
156 struct snd_pcm_runtime *runtime = substream->runtime;
157 ssize_t result;
158 snd_pcm_sframes_t frames;
159
160 try_again:
161 if (runtime->state == SNDRV_PCM_STATE_XRUN ||
162 runtime->state == SNDRV_PCM_STATE_SUSPENDED) {
163 result = snd_pcm_kernel_ioctl(substream,
164 SNDRV_PCM_IOCTL_PREPARE, NULL);
165 if (result < 0) {
166 ERROR(card, "Preparing sound card failed: %d\n",
167 (int)result);
168 return result;
169 }
170 }
171
172 frames = bytes_to_frames(runtime, count);
173 result = snd_pcm_kernel_write(snd->substream, buf, frames);
174 if (result != frames) {
175 ERROR(card, "Playback error: %d\n", (int)result);
176 goto try_again;
177 }
178
179 return 0;
180 }
181
u_audio_get_playback_channels(struct gaudio * card)182 int u_audio_get_playback_channels(struct gaudio *card)
183 {
184 return card->playback.channels;
185 }
186
u_audio_get_playback_rate(struct gaudio * card)187 int u_audio_get_playback_rate(struct gaudio *card)
188 {
189 return card->playback.rate;
190 }
191
192 /*
193 * Open ALSA PCM and control device files
194 * Initial the PCM or control device
195 */
gaudio_open_snd_dev(struct gaudio * card)196 static int gaudio_open_snd_dev(struct gaudio *card)
197 {
198 struct snd_pcm_file *pcm_file;
199 struct gaudio_snd_dev *snd;
200 struct f_uac1_legacy_opts *opts;
201 char *fn_play, *fn_cap, *fn_cntl;
202
203 opts = container_of(card->func.fi, struct f_uac1_legacy_opts,
204 func_inst);
205 fn_play = opts->fn_play;
206 fn_cap = opts->fn_cap;
207 fn_cntl = opts->fn_cntl;
208
209 /* Open control device */
210 snd = &card->control;
211 snd->filp = filp_open(fn_cntl, O_RDWR, 0);
212 if (IS_ERR(snd->filp)) {
213 int ret = PTR_ERR(snd->filp);
214 ERROR(card, "unable to open sound control device file: %s\n",
215 fn_cntl);
216 snd->filp = NULL;
217 return ret;
218 }
219 snd->card = card;
220
221 /* Open PCM playback device and setup substream */
222 snd = &card->playback;
223 snd->filp = filp_open(fn_play, O_WRONLY, 0);
224 if (IS_ERR(snd->filp)) {
225 int ret = PTR_ERR(snd->filp);
226
227 ERROR(card, "No such PCM playback device: %s\n", fn_play);
228 snd->filp = NULL;
229 return ret;
230 }
231 pcm_file = snd->filp->private_data;
232 snd->substream = pcm_file->substream;
233 snd->card = card;
234 playback_default_hw_params(snd);
235
236 /* Open PCM capture device and setup substream */
237 snd = &card->capture;
238 snd->filp = filp_open(fn_cap, O_RDONLY, 0);
239 if (IS_ERR(snd->filp)) {
240 ERROR(card, "No such PCM capture device: %s\n", fn_cap);
241 snd->substream = NULL;
242 snd->card = NULL;
243 snd->filp = NULL;
244 } else {
245 pcm_file = snd->filp->private_data;
246 snd->substream = pcm_file->substream;
247 snd->card = card;
248 }
249
250 return 0;
251 }
252
253 /*
254 * Close ALSA PCM and control device files
255 */
gaudio_close_snd_dev(struct gaudio * gau)256 static int gaudio_close_snd_dev(struct gaudio *gau)
257 {
258 struct gaudio_snd_dev *snd;
259
260 /* Close control device */
261 snd = &gau->control;
262 if (snd->filp)
263 filp_close(snd->filp, NULL);
264
265 /* Close PCM playback device and setup substream */
266 snd = &gau->playback;
267 if (snd->filp)
268 filp_close(snd->filp, NULL);
269
270 /* Close PCM capture device and setup substream */
271 snd = &gau->capture;
272 if (snd->filp)
273 filp_close(snd->filp, NULL);
274
275 return 0;
276 }
277
278 /*
279 * gaudio_setup - setup ALSA interface and preparing for USB transfer
280 *
281 * This sets up PCM, mixer or MIDI ALSA devices fore USB gadget using.
282 *
283 * Returns negative errno, or zero on success
284 */
gaudio_setup(struct gaudio * card)285 int gaudio_setup(struct gaudio *card)
286 {
287 int ret;
288
289 ret = gaudio_open_snd_dev(card);
290 if (ret)
291 ERROR(card, "we need at least one control device\n");
292
293 return ret;
294
295 }
296
297 /*
298 * gaudio_cleanup - remove ALSA device interface
299 *
300 * This is called to free all resources allocated by @gaudio_setup().
301 */
gaudio_cleanup(struct gaudio * the_card)302 void gaudio_cleanup(struct gaudio *the_card)
303 {
304 if (the_card)
305 gaudio_close_snd_dev(the_card);
306 }
307
308