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path: root/drivers/usb/gadget/u_uac1.c
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-rw-r--r--drivers/usb/gadget/u_uac1.c327
1 files changed, 327 insertions, 0 deletions
diff --git a/drivers/usb/gadget/u_uac1.c b/drivers/usb/gadget/u_uac1.c
new file mode 100644
index 000000000000..af9898982059
--- /dev/null
+++ b/drivers/usb/gadget/u_uac1.c
@@ -0,0 +1,327 @@
1/*
2 * u_uac1.c -- ALSA audio utilities for Gadget stack
3 *
4 * Copyright (C) 2008 Bryan Wu <cooloney@kernel.org>
5 * Copyright (C) 2008 Analog Devices, Inc
6 *
7 * Enter bugs at http://blackfin.uclinux.org/
8 *
9 * Licensed under the GPL-2 or later.
10 */
11
12#include <linux/kernel.h>
13#include <linux/slab.h>
14#include <linux/device.h>
15#include <linux/delay.h>
16#include <linux/ctype.h>
17#include <linux/random.h>
18#include <linux/syscalls.h>
19
20#include "u_uac1.h"
21
22/*
23 * This component encapsulates the ALSA devices for USB audio gadget
24 */
25
26#define FILE_PCM_PLAYBACK "/dev/snd/pcmC0D0p"
27#define FILE_PCM_CAPTURE "/dev/snd/pcmC0D0c"
28#define FILE_CONTROL "/dev/snd/controlC0"
29
30static char *fn_play = FILE_PCM_PLAYBACK;
31module_param(fn_play, charp, S_IRUGO);
32MODULE_PARM_DESC(fn_play, "Playback PCM device file name");
33
34static char *fn_cap = FILE_PCM_CAPTURE;
35module_param(fn_cap, charp, S_IRUGO);
36MODULE_PARM_DESC(fn_cap, "Capture PCM device file name");
37
38static char *fn_cntl = FILE_CONTROL;
39module_param(fn_cntl, charp, S_IRUGO);
40MODULE_PARM_DESC(fn_cntl, "Control device file name");
41
42/*-------------------------------------------------------------------------*/
43
44/**
45 * Some ALSA internal helper functions
46 */
47static int snd_interval_refine_set(struct snd_interval *i, unsigned int val)
48{
49 struct snd_interval t;
50 t.empty = 0;
51 t.min = t.max = val;
52 t.openmin = t.openmax = 0;
53 t.integer = 1;
54 return snd_interval_refine(i, &t);
55}
56
57static int _snd_pcm_hw_param_set(struct snd_pcm_hw_params *params,
58 snd_pcm_hw_param_t var, unsigned int val,
59 int dir)
60{
61 int changed;
62 if (hw_is_mask(var)) {
63 struct snd_mask *m = hw_param_mask(params, var);
64 if (val == 0 && dir < 0) {
65 changed = -EINVAL;
66 snd_mask_none(m);
67 } else {
68 if (dir > 0)
69 val++;
70 else if (dir < 0)
71 val--;
72 changed = snd_mask_refine_set(
73 hw_param_mask(params, var), val);
74 }
75 } else if (hw_is_interval(var)) {
76 struct snd_interval *i = hw_param_interval(params, var);
77 if (val == 0 && dir < 0) {
78 changed = -EINVAL;
79 snd_interval_none(i);
80 } else if (dir == 0)
81 changed = snd_interval_refine_set(i, val);
82 else {
83 struct snd_interval t;
84 t.openmin = 1;
85 t.openmax = 1;
86 t.empty = 0;
87 t.integer = 0;
88 if (dir < 0) {
89 t.min = val - 1;
90 t.max = val;
91 } else {
92 t.min = val;
93 t.max = val+1;
94 }
95 changed = snd_interval_refine(i, &t);
96 }
97 } else
98 return -EINVAL;
99 if (changed) {
100 params->cmask |= 1 << var;
101 params->rmask |= 1 << var;
102 }
103 return changed;
104}
105/*-------------------------------------------------------------------------*/
106
107/**
108 * Set default hardware params
109 */
110static int playback_default_hw_params(struct gaudio_snd_dev *snd)
111{
112 struct snd_pcm_substream *substream = snd->substream;
113 struct snd_pcm_hw_params *params;
114 snd_pcm_sframes_t result;
115
116 /*
117 * SNDRV_PCM_ACCESS_RW_INTERLEAVED,
118 * SNDRV_PCM_FORMAT_S16_LE
119 * CHANNELS: 2
120 * RATE: 48000
121 */
122 snd->access = SNDRV_PCM_ACCESS_RW_INTERLEAVED;
123 snd->format = SNDRV_PCM_FORMAT_S16_LE;
124 snd->channels = 2;
125 snd->rate = 48000;
126
127 params = kzalloc(sizeof(*params), GFP_KERNEL);
128 if (!params)
129 return -ENOMEM;
130
131 _snd_pcm_hw_params_any(params);
132 _snd_pcm_hw_param_set(params, SNDRV_PCM_HW_PARAM_ACCESS,
133 snd->access, 0);
134 _snd_pcm_hw_param_set(params, SNDRV_PCM_HW_PARAM_FORMAT,
135 snd->format, 0);
136 _snd_pcm_hw_param_set(params, SNDRV_PCM_HW_PARAM_CHANNELS,
137 snd->channels, 0);
138 _snd_pcm_hw_param_set(params, SNDRV_PCM_HW_PARAM_RATE,
139 snd->rate, 0);
140
141 snd_pcm_kernel_ioctl(substream, SNDRV_PCM_IOCTL_DROP, NULL);
142 snd_pcm_kernel_ioctl(substream, SNDRV_PCM_IOCTL_HW_PARAMS, params);
143
144 result = snd_pcm_kernel_ioctl(substream, SNDRV_PCM_IOCTL_PREPARE, NULL);
145 if (result < 0) {
146 ERROR(snd->card,
147 "Preparing sound card failed: %d\n", (int)result);
148 kfree(params);
149 return result;
150 }
151
152 /* Store the hardware parameters */
153 snd->access = params_access(params);
154 snd->format = params_format(params);
155 snd->channels = params_channels(params);
156 snd->rate = params_rate(params);
157
158 kfree(params);
159
160 INFO(snd->card,
161 "Hardware params: access %x, format %x, channels %d, rate %d\n",
162 snd->access, snd->format, snd->channels, snd->rate);
163
164 return 0;
165}
166
167/**
168 * Playback audio buffer data by ALSA PCM device
169 */
170static size_t u_audio_playback(struct gaudio *card, void *buf, size_t count)
171{
172 struct gaudio_snd_dev *snd = &card->playback;
173 struct snd_pcm_substream *substream = snd->substream;
174 struct snd_pcm_runtime *runtime = substream->runtime;
175 mm_segment_t old_fs;
176 ssize_t result;
177 snd_pcm_sframes_t frames;
178
179try_again:
180 if (runtime->status->state == SNDRV_PCM_STATE_XRUN ||
181 runtime->status->state == SNDRV_PCM_STATE_SUSPENDED) {
182 result = snd_pcm_kernel_ioctl(substream,
183 SNDRV_PCM_IOCTL_PREPARE, NULL);
184 if (result < 0) {
185 ERROR(card, "Preparing sound card failed: %d\n",
186 (int)result);
187 return result;
188 }
189 }
190
191 frames = bytes_to_frames(runtime, count);
192 old_fs = get_fs();
193 set_fs(KERNEL_DS);
194 result = snd_pcm_lib_write(snd->substream, buf, frames);
195 if (result != frames) {
196 ERROR(card, "Playback error: %d\n", (int)result);
197 set_fs(old_fs);
198 goto try_again;
199 }
200 set_fs(old_fs);
201
202 return 0;
203}
204
205static int u_audio_get_playback_channels(struct gaudio *card)
206{
207 return card->playback.channels;
208}
209
210static int u_audio_get_playback_rate(struct gaudio *card)
211{
212 return card->playback.rate;
213}
214
215/**
216 * Open ALSA PCM and control device files
217 * Initial the PCM or control device
218 */
219static int gaudio_open_snd_dev(struct gaudio *card)
220{
221 struct snd_pcm_file *pcm_file;
222 struct gaudio_snd_dev *snd;
223
224 if (!card)
225 return -ENODEV;
226
227 /* Open control device */
228 snd = &card->control;
229 snd->filp = filp_open(fn_cntl, O_RDWR, 0);
230 if (IS_ERR(snd->filp)) {
231 int ret = PTR_ERR(snd->filp);
232 ERROR(card, "unable to open sound control device file: %s\n",
233 fn_cntl);
234 snd->filp = NULL;
235 return ret;
236 }
237 snd->card = card;
238
239 /* Open PCM playback device and setup substream */
240 snd = &card->playback;
241 snd->filp = filp_open(fn_play, O_WRONLY, 0);
242 if (IS_ERR(snd->filp)) {
243 ERROR(card, "No such PCM playback device: %s\n", fn_play);
244 snd->filp = NULL;
245 }
246 pcm_file = snd->filp->private_data;
247 snd->substream = pcm_file->substream;
248 snd->card = card;
249 playback_default_hw_params(snd);
250
251 /* Open PCM capture device and setup substream */
252 snd = &card->capture;
253 snd->filp = filp_open(fn_cap, O_RDONLY, 0);
254 if (IS_ERR(snd->filp)) {
255 ERROR(card, "No such PCM capture device: %s\n", fn_cap);
256 snd->substream = NULL;
257 snd->card = NULL;
258 snd->filp = NULL;
259 } else {
260 pcm_file = snd->filp->private_data;
261 snd->substream = pcm_file->substream;
262 snd->card = card;
263 }
264
265 return 0;
266}
267
268/**
269 * Close ALSA PCM and control device files
270 */
271static int gaudio_close_snd_dev(struct gaudio *gau)
272{
273 struct gaudio_snd_dev *snd;
274
275 /* Close control device */
276 snd = &gau->control;
277 if (snd->filp)
278 filp_close(snd->filp, current->files);
279
280 /* Close PCM playback device and setup substream */
281 snd = &gau->playback;
282 if (snd->filp)
283 filp_close(snd->filp, current->files);
284
285 /* Close PCM capture device and setup substream */
286 snd = &gau->capture;
287 if (snd->filp)
288 filp_close(snd->filp, current->files);
289
290 return 0;
291}
292
293static struct gaudio *the_card;
294/**
295 * gaudio_setup - setup ALSA interface and preparing for USB transfer
296 *
297 * This sets up PCM, mixer or MIDI ALSA devices fore USB gadget using.
298 *
299 * Returns negative errno, or zero on success
300 */
301int __init gaudio_setup(struct gaudio *card)
302{
303 int ret;
304
305 ret = gaudio_open_snd_dev(card);
306 if (ret)
307 ERROR(card, "we need at least one control device\n");
308 else if (!the_card)
309 the_card = card;
310
311 return ret;
312
313}
314
315/**
316 * gaudio_cleanup - remove ALSA device interface
317 *
318 * This is called to free all resources allocated by @gaudio_setup().
319 */
320void gaudio_cleanup(void)
321{
322 if (the_card) {
323 gaudio_close_snd_dev(the_card);
324 the_card = NULL;
325 }
326}
327
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