drivers/usb/gadget/function/u_uac1.c

   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/module.h>
  14 #include <linux/slab.h>
  15 #include <linux/device.h>
  16 #include <linux/delay.h>
  17 #include <linux/ctype.h>
  18 #include <linux/random.h>
  19 #include <linux/syscalls.h>
  20
  21 #include "u_uac1.h"
  22
  23 /*
  24  * This component encapsulates the ALSA devices for USB audio gadget
  25  */
  26
  27 /*-------------------------------------------------------------------------*/
  28
  29 /**
  30  * Some ALSA internal helper functions
  31  */
  32 static int snd_interval_refine_set(struct snd_interval *i, unsigned int val)
  33 {
  34         struct snd_interval t;
  35         t.empty = 0;
  36         t.min = t.max = val;
  37         t.openmin = t.openmax = 0;
  38         t.integer = 1;
  39         return snd_interval_refine(i, &t);
  40 }
  41
  42 static int _snd_pcm_hw_param_set(struct snd_pcm_hw_params *params,
  43                                  snd_pcm_hw_param_t var, unsigned int val,
  44                                  int dir)
  45 {
  46         int changed;
  47         if (hw_is_mask(var)) {
  48                 struct snd_mask *m = hw_param_mask(params, var);
  49                 if (val == 0 && dir < 0) {
  50                         changed = -EINVAL;
  51                         snd_mask_none(m);
  52                 } else {
  53                         if (dir > 0)
  54                                 val++;
  55                         else if (dir < 0)
  56                                 val--;
  57                         changed = snd_mask_refine_set(
  58                                         hw_param_mask(params, var), val);
  59                 }
  60         } else if (hw_is_interval(var)) {
  61                 struct snd_interval *i = hw_param_interval(params, var);
  62                 if (val == 0 && dir < 0) {
  63                         changed = -EINVAL;
  64                         snd_interval_none(i);
  65                 } else if (dir == 0)
  66                         changed = snd_interval_refine_set(i, val);
  67                 else {
  68                         struct snd_interval t;
  69                         t.openmin = 1;
  70                         t.openmax = 1;
  71                         t.empty = 0;
  72                         t.integer = 0;
  73                         if (dir < 0) {
  74                                 t.min = val - 1;
  75                                 t.max = val;
  76                         } else {
  77                                 t.min = val;
  78                                 t.max = val+1;
  79                         }
  80                         changed = snd_interval_refine(i, &t);
  81                 }
  82         } else
  83                 return -EINVAL;
  84         if (changed) {
  85                 params->cmask |= 1 << var;
  86                 params->rmask |= 1 << var;
  87         }
  88         return changed;
  89 }
  90 /*-------------------------------------------------------------------------*/
  91
  92 /**
  93  * Set default hardware params
  94  */
  95 static int playback_default_hw_params(struct gaudio_snd_dev *snd)
  96 {
  97         struct snd_pcm_substream *substream = snd->substream;
  98         struct snd_pcm_hw_params *params;
  99         snd_pcm_sframes_t result;
 100
 101        /*
 102         * SNDRV_PCM_ACCESS_RW_INTERLEAVED,
 103         * SNDRV_PCM_FORMAT_S16_LE
 104         * CHANNELS: 2
 105         * RATE: 48000
 106         */
 107         snd->access = SNDRV_PCM_ACCESS_RW_INTERLEAVED;
 108         snd->format = SNDRV_PCM_FORMAT_S16_LE;
 109         snd->channels = 2;
 110         snd->rate = 48000;
 111
 112         params = kzalloc(sizeof(*params), GFP_KERNEL);
 113         if (!params)
 114                 return -ENOMEM;
 115
 116         _snd_pcm_hw_params_any(params);
 117         _snd_pcm_hw_param_set(params, SNDRV_PCM_HW_PARAM_ACCESS,
 118                         snd->access, 0);
 119         _snd_pcm_hw_param_set(params, SNDRV_PCM_HW_PARAM_FORMAT,
 120                         snd->format, 0);
 121         _snd_pcm_hw_param_set(params, SNDRV_PCM_HW_PARAM_CHANNELS,
 122                         snd->channels, 0);
 123         _snd_pcm_hw_param_set(params, SNDRV_PCM_HW_PARAM_RATE,
 124                         snd->rate, 0);
 125
 126         snd_pcm_kernel_ioctl(substream, SNDRV_PCM_IOCTL_DROP, NULL);
 127         snd_pcm_kernel_ioctl(substream, SNDRV_PCM_IOCTL_HW_PARAMS, params);
 128
 129         result = snd_pcm_kernel_ioctl(substream, SNDRV_PCM_IOCTL_PREPARE, NULL);
 130         if (result < 0) {
 131                 ERROR(snd->card,
 132                         "Preparing sound card failed: %d\n", (int)result);
 133                 kfree(params);
 134                 return result;
 135         }
 136
 137         /* Store the hardware parameters */
 138         snd->access = params_access(params);
 139         snd->format = params_format(params);
 140         snd->channels = params_channels(params);
 141         snd->rate = params_rate(params);
 142
 143         kfree(params);
 144
 145         INFO(snd->card,
 146                 "Hardware params: access %x, format %x, channels %d, rate %d\n",
 147                 snd->access, snd->format, snd->channels, snd->rate);
 148
 149         return 0;
 150 }
 151
 152 /**
 153  * Playback audio buffer data by ALSA PCM device
 154  */
 155 size_t u_audio_playback(struct gaudio *card, void *buf, size_t count)
 156 {
 157         struct gaudio_snd_dev   *snd = &card->playback;
 158         struct snd_pcm_substream *substream = snd->substream;
 159         struct snd_pcm_runtime *runtime = substream->runtime;
 160         mm_segment_t old_fs;
 161         ssize_t result;
 162         snd_pcm_sframes_t frames;
 163
 164 try_again:
 165         if (runtime->status->state == SNDRV_PCM_STATE_XRUN ||
 166                 runtime->status->state == SNDRV_PCM_STATE_SUSPENDED) {
 167                 result = snd_pcm_kernel_ioctl(substream,
 168                                 SNDRV_PCM_IOCTL_PREPARE, NULL);
 169                 if (result < 0) {
 170                         ERROR(card, "Preparing sound card failed: %d\n",
 171                                         (int)result);
 172                         return result;
 173                 }
 174         }
 175
 176         frames = bytes_to_frames(runtime, count);
 177         old_fs = get_fs();
 178         set_fs(KERNEL_DS);
 179         result = snd_pcm_lib_write(snd->substream, (void __user *)buf, frames);
 180         if (result != frames) {
 181                 ERROR(card, "Playback error: %d\n", (int)result);
 182                 set_fs(old_fs);
 183                 goto try_again;
 184         }
 185         set_fs(old_fs);
 186
 187         return 0;
 188 }
 189
 190 int u_audio_get_playback_channels(struct gaudio *card)
 191 {
 192         return card->playback.channels;
 193 }
 194
 195 int u_audio_get_playback_rate(struct gaudio *card)
 196 {
 197         return card->playback.rate;
 198 }
 199
 200 /**
 201  * Open ALSA PCM and control device files
 202  * Initial the PCM or control device
 203  */
 204 static int gaudio_open_snd_dev(struct gaudio *card)
 205 {
 206         struct snd_pcm_file *pcm_file;
 207         struct gaudio_snd_dev *snd;
 208         struct f_uac1_opts *opts;
 209         char *fn_play, *fn_cap, *fn_cntl;
 210
 211         opts = container_of(card->func.fi, struct f_uac1_opts, func_inst);
 212         fn_play = opts->fn_play;
 213         fn_cap = opts->fn_cap;
 214         fn_cntl = opts->fn_cntl;
 215
 216         /* Open control device */
 217         snd = &card->control;
 218         snd->filp = filp_open(fn_cntl, O_RDWR, 0);
 219         if (IS_ERR(snd->filp)) {
 220                 int ret = PTR_ERR(snd->filp);
 221                 ERROR(card, "unable to open sound control device file: %s\n",
 222                                 fn_cntl);
 223                 snd->filp = NULL;
 224                 return ret;
 225         }
 226         snd->card = card;
 227
 228         /* Open PCM playback device and setup substream */
 229         snd = &card->playback;
 230         snd->filp = filp_open(fn_play, O_WRONLY, 0);
 231         if (IS_ERR(snd->filp)) {
 232                 int ret = PTR_ERR(snd->filp);
 233
 234                 ERROR(card, "No such PCM playback device: %s\n", fn_play);
 235                 snd->filp = NULL;
 236                 return ret;
 237         }
 238         pcm_file = snd->filp->private_data;
 239         snd->substream = pcm_file->substream;
 240         snd->card = card;
 241         playback_default_hw_params(snd);
 242
 243         /* Open PCM capture device and setup substream */
 244         snd = &card->capture;
 245         snd->filp = filp_open(fn_cap, O_RDONLY, 0);
 246         if (IS_ERR(snd->filp)) {
 247                 ERROR(card, "No such PCM capture device: %s\n", fn_cap);
 248                 snd->substream = NULL;
 249                 snd->card = NULL;
 250                 snd->filp = NULL;
 251         } else {
 252                 pcm_file = snd->filp->private_data;
 253                 snd->substream = pcm_file->substream;
 254                 snd->card = card;
 255         }
 256
 257         return 0;
 258 }
 259
 260 /**
 261  * Close ALSA PCM and control device files
 262  */
 263 static int gaudio_close_snd_dev(struct gaudio *gau)
 264 {
 265         struct gaudio_snd_dev   *snd;
 266
 267         /* Close control device */
 268         snd = &gau->control;
 269         if (snd->filp)
 270                 filp_close(snd->filp, NULL);
 271
 272         /* Close PCM playback device and setup substream */
 273         snd = &gau->playback;
 274         if (snd->filp)
 275                 filp_close(snd->filp, NULL);
 276
 277         /* Close PCM capture device and setup substream */
 278         snd = &gau->capture;
 279         if (snd->filp)
 280                 filp_close(snd->filp, NULL);
 281
 282         return 0;
 283 }
 284
 285 /**
 286  * gaudio_setup - setup ALSA interface and preparing for USB transfer
 287  *
 288  * This sets up PCM, mixer or MIDI ALSA devices fore USB gadget using.
 289  *
 290  * Returns negative errno, or zero on success
 291  */
 292 int gaudio_setup(struct gaudio *card)
 293 {
 294         int     ret;
 295
 296         ret = gaudio_open_snd_dev(card);
 297         if (ret)
 298                 ERROR(card, "we need at least one control device\n");
 299
 300         return ret;
 301
 302 }
 303
 304 /**
 305  * gaudio_cleanup - remove ALSA device interface
 306  *
 307  * This is called to free all resources allocated by @gaudio_setup().
 308  */
 309 void gaudio_cleanup(struct gaudio *the_card)
 310 {
 311         if (the_card)
 312                 gaudio_close_snd_dev(the_card);
 313 }
 314