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
|
// SPDX-License-Identifier: GPL-2.0+
/*
* u_uac1.c -- ALSA audio utilities for Gadget stack
*
* Copyright (C) 2008 Bryan Wu <cooloney@kernel.org>
* Copyright (C) 2008 Analog Devices, Inc
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/device.h>
#include <linux/delay.h>
#include <linux/ctype.h>
#include <linux/random.h>
#include <linux/syscalls.h>
#include "u_uac1_legacy.h"
/*
* This component encapsulates the ALSA devices for USB audio gadget
*/
/*-------------------------------------------------------------------------*/
/**
* Some ALSA internal helper functions
*/
static int snd_interval_refine_set(struct snd_interval *i, unsigned int val)
{
struct snd_interval t;
t.empty = 0;
t.min = t.max = val;
t.openmin = t.openmax = 0;
t.integer = 1;
return snd_interval_refine(i, &t);
}
static int _snd_pcm_hw_param_set(struct snd_pcm_hw_params *params,
snd_pcm_hw_param_t var, unsigned int val,
int dir)
{
int changed;
if (hw_is_mask(var)) {
struct snd_mask *m = hw_param_mask(params, var);
if (val == 0 && dir < 0) {
changed = -EINVAL;
snd_mask_none(m);
} else {
if (dir > 0)
val++;
else if (dir < 0)
val--;
changed = snd_mask_refine_set(
hw_param_mask(params, var), val);
}
} else if (hw_is_interval(var)) {
struct snd_interval *i = hw_param_interval(params, var);
if (val == 0 && dir < 0) {
changed = -EINVAL;
snd_interval_none(i);
} else if (dir == 0)
changed = snd_interval_refine_set(i, val);
else {
struct snd_interval t;
t.openmin = 1;
t.openmax = 1;
t.empty = 0;
t.integer = 0;
if (dir < 0) {
t.min = val - 1;
t.max = val;
} else {
t.min = val;
t.max = val+1;
}
changed = snd_interval_refine(i, &t);
}
} else
return -EINVAL;
if (changed) {
params->cmask |= 1 << var;
params->rmask |= 1 << var;
}
return changed;
}
/*-------------------------------------------------------------------------*/
/**
* Set default hardware params
*/
static int playback_default_hw_params(struct gaudio_snd_dev *snd)
{
struct snd_pcm_substream *substream = snd->substream;
struct snd_pcm_hw_params *params;
snd_pcm_sframes_t result;
/*
* SNDRV_PCM_ACCESS_RW_INTERLEAVED,
* SNDRV_PCM_FORMAT_S16_LE
* CHANNELS: 2
* RATE: 48000
*/
snd->access = SNDRV_PCM_ACCESS_RW_INTERLEAVED;
snd->format = SNDRV_PCM_FORMAT_S16_LE;
snd->channels = 2;
snd->rate = 48000;
params = kzalloc(sizeof(*params), GFP_KERNEL);
if (!params)
return -ENOMEM;
_snd_pcm_hw_params_any(params);
_snd_pcm_hw_param_set(params, SNDRV_PCM_HW_PARAM_ACCESS,
snd->access, 0);
_snd_pcm_hw_param_set(params, SNDRV_PCM_HW_PARAM_FORMAT,
snd->format, 0);
_snd_pcm_hw_param_set(params, SNDRV_PCM_HW_PARAM_CHANNELS,
snd->channels, 0);
_snd_pcm_hw_param_set(params, SNDRV_PCM_HW_PARAM_RATE,
snd->rate, 0);
snd_pcm_kernel_ioctl(substream, SNDRV_PCM_IOCTL_DROP, NULL);
snd_pcm_kernel_ioctl(substream, SNDRV_PCM_IOCTL_HW_PARAMS, params);
result = snd_pcm_kernel_ioctl(substream, SNDRV_PCM_IOCTL_PREPARE, NULL);
if (result < 0) {
ERROR(snd->card,
"Preparing sound card failed: %d\n", (int)result);
kfree(params);
return result;
}
/* Store the hardware parameters */
snd->access = params_access(params);
snd->format = params_format(params);
snd->channels = params_channels(params);
snd->rate = params_rate(params);
kfree(params);
INFO(snd->card,
"Hardware params: access %x, format %x, channels %d, rate %d\n",
snd->access, snd->format, snd->channels, snd->rate);
return 0;
}
/**
* Playback audio buffer data by ALSA PCM device
*/
size_t u_audio_playback(struct gaudio *card, void *buf, size_t count)
{
struct gaudio_snd_dev *snd = &card->playback;
struct snd_pcm_substream *substream = snd->substream;
struct snd_pcm_runtime *runtime = substream->runtime;
ssize_t result;
snd_pcm_sframes_t frames;
try_again:
if (runtime->status->state == SNDRV_PCM_STATE_XRUN ||
runtime->status->state == SNDRV_PCM_STATE_SUSPENDED) {
result = snd_pcm_kernel_ioctl(substream,
SNDRV_PCM_IOCTL_PREPARE, NULL);
if (result < 0) {
ERROR(card, "Preparing sound card failed: %d\n",
(int)result);
return result;
}
}
frames = bytes_to_frames(runtime, count);
result = snd_pcm_kernel_write(snd->substream, buf, frames);
if (result != frames) {
ERROR(card, "Playback error: %d\n", (int)result);
goto try_again;
}
return 0;
}
int u_audio_get_playback_channels(struct gaudio *card)
{
return card->playback.channels;
}
int u_audio_get_playback_rate(struct gaudio *card)
{
return card->playback.rate;
}
/**
* Open ALSA PCM and control device files
* Initial the PCM or control device
*/
static int gaudio_open_snd_dev(struct gaudio *card)
{
struct snd_pcm_file *pcm_file;
struct gaudio_snd_dev *snd;
struct f_uac1_legacy_opts *opts;
char *fn_play, *fn_cap, *fn_cntl;
opts = container_of(card->func.fi, struct f_uac1_legacy_opts,
func_inst);
fn_play = opts->fn_play;
fn_cap = opts->fn_cap;
fn_cntl = opts->fn_cntl;
/* Open control device */
snd = &card->control;
snd->filp = filp_open(fn_cntl, O_RDWR, 0);
if (IS_ERR(snd->filp)) {
int ret = PTR_ERR(snd->filp);
ERROR(card, "unable to open sound control device file: %s\n",
fn_cntl);
snd->filp = NULL;
return ret;
}
snd->card = card;
/* Open PCM playback device and setup substream */
snd = &card->playback;
snd->filp = filp_open(fn_play, O_WRONLY, 0);
if (IS_ERR(snd->filp)) {
int ret = PTR_ERR(snd->filp);
ERROR(card, "No such PCM playback device: %s\n", fn_play);
snd->filp = NULL;
return ret;
}
pcm_file = snd->filp->private_data;
snd->substream = pcm_file->substream;
snd->card = card;
playback_default_hw_params(snd);
/* Open PCM capture device and setup substream */
snd = &card->capture;
snd->filp = filp_open(fn_cap, O_RDONLY, 0);
if (IS_ERR(snd->filp)) {
ERROR(card, "No such PCM capture device: %s\n", fn_cap);
snd->substream = NULL;
snd->card = NULL;
snd->filp = NULL;
} else {
pcm_file = snd->filp->private_data;
snd->substream = pcm_file->substream;
snd->card = card;
}
return 0;
}
/**
* Close ALSA PCM and control device files
*/
static int gaudio_close_snd_dev(struct gaudio *gau)
{
struct gaudio_snd_dev *snd;
/* Close control device */
snd = &gau->control;
if (snd->filp)
filp_close(snd->filp, NULL);
/* Close PCM playback device and setup substream */
snd = &gau->playback;
if (snd->filp)
filp_close(snd->filp, NULL);
/* Close PCM capture device and setup substream */
snd = &gau->capture;
if (snd->filp)
filp_close(snd->filp, NULL);
return 0;
}
/**
* gaudio_setup - setup ALSA interface and preparing for USB transfer
*
* This sets up PCM, mixer or MIDI ALSA devices fore USB gadget using.
*
* Returns negative errno, or zero on success
*/
int gaudio_setup(struct gaudio *card)
{
int ret;
ret = gaudio_open_snd_dev(card);
if (ret)
ERROR(card, "we need at least one control device\n");
return ret;
}
/**
* gaudio_cleanup - remove ALSA device interface
*
* This is called to free all resources allocated by @gaudio_setup().
*/
void gaudio_cleanup(struct gaudio *the_card)
{
if (the_card)
gaudio_close_snd_dev(the_card);
}
|
