/*
* u_audio.c -- ALSA audio utilities for Gadget stack
*
* Copyright (C) 2008 Bryan Wu <cooloney@kernel.org>
* Copyright (C) 2008 Analog Devices, Inc
*
* Enter bugs at http://blackfin.uclinux.org/
*
* Licensed under the GPL-2 or later.
*/
#include <linux/kernel.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_audio.h"
/*
* This component encapsulates the ALSA devices for USB audio gadget
*/
#define FILE_PCM_PLAYBACK "/dev/snd/pcmC0D0p"
#define FILE_PCM_CAPTURE "/dev/snd/pcmC0D0c"
#define FILE_CONTROL "/dev/snd/controlC0"
static char *fn_play = FILE_PCM_PLAYBACK;
module_param(fn_play, charp, S_IRUGO);
MODULE_PARM_DESC(fn_play, "Playback PCM device file name");
static char *fn_cap = FILE_PCM_CAPTURE;
module_param(fn_cap, charp, S_IRUGO);
MODULE_PARM_DESC(fn_cap, "Capture PCM device file name");
static char *fn_cntl = FILE_CONTROL;
module_param(fn_cntl, charp, S_IRUGO);
MODULE_PARM_DESC(fn_cntl, "Control device file name");
/*-------------------------------------------------------------------------*/
/**
* 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
*/
static 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;
mm_segment_t old_fs;
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);
old_fs = get_fs();
set_fs(KERNEL_DS);
result = snd_pcm_lib_write(snd->substream, buf, frames);
if (result != frames) {
ERROR(card, "Playback error: %d\n", (int)result);
set_fs(old_fs);
goto try_again;
}
set_fs(old_fs);
return 0;
}
static int u_audio_get_playback_channels(struct gaudio *card)
{
return card->playback.channels;
}
static 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;
if (!card)
return -ENODEV;
/* 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)) {
ERROR(card, "No such PCM playback device: %s\n", fn_play);
snd->filp = NULL;
}
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, current->files);
/* Close PCM playback device and setup substream */
snd = &gau->playback;
if (snd->filp)
filp_close(snd->filp, current->files);
/* Close PCM capture device and setup substream */
snd = &gau->capture;
if (snd->filp)
filp_close(snd->filp, current->files);
return 0;
}
static struct gaudio *the_card;
/**
* 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 __init 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");
else if (!the_card)
the_card = card;
return ret;
}
/**
* gaudio_cleanup - remove ALSA device interface
*
* This is called to free all resources allocated by @gaudio_setup().
*/
void gaudio_cleanup(void)
{
if (the_card) {
gaudio_close_snd_dev(the_card);
the_card = NULL;
}
}
