linux/sound/oss/sh_dac_audio.c
Roel Kluin 84ed1a1942 ALSA: Cleanup redundant tests on unsigned
The variables are unsigned so the test `>= 0' is always true,
the `< 0' test always fails. In these cases the other part of
the test catches wrapped values.

In dac_audio_write() there does not occur a test for wrapped
values, but the test appears redundant.

Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2009-10-30 12:25:07 +01:00

309 lines
6.3 KiB
C

/*
* sound/oss/sh_dac_audio.c
*
* SH DAC based sound :(
*
* Copyright (C) 2004,2005 Andriy Skulysh
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/linkage.h>
#include <linux/slab.h>
#include <linux/fs.h>
#include <linux/sound.h>
#include <linux/soundcard.h>
#include <linux/interrupt.h>
#include <linux/hrtimer.h>
#include <asm/io.h>
#include <asm/uaccess.h>
#include <asm/irq.h>
#include <asm/delay.h>
#include <asm/clock.h>
#include <cpu/dac.h>
#include <asm/machvec.h>
#include <mach/hp6xx.h>
#include <asm/hd64461.h>
#define MODNAME "sh_dac_audio"
#define BUFFER_SIZE 48000
static int rate;
static int empty;
static char *data_buffer, *buffer_begin, *buffer_end;
static int in_use, device_major;
static struct hrtimer hrtimer;
static ktime_t wakeups_per_second;
static void dac_audio_start_timer(void)
{
hrtimer_start(&hrtimer, wakeups_per_second, HRTIMER_MODE_REL);
}
static void dac_audio_stop_timer(void)
{
hrtimer_cancel(&hrtimer);
}
static void dac_audio_reset(void)
{
dac_audio_stop_timer();
buffer_begin = buffer_end = data_buffer;
empty = 1;
}
static void dac_audio_sync(void)
{
while (!empty)
schedule();
}
static void dac_audio_start(void)
{
if (mach_is_hp6xx()) {
u16 v = __raw_readw(HD64461_GPADR);
v &= ~HD64461_GPADR_SPEAKER;
__raw_writew(v, HD64461_GPADR);
}
sh_dac_enable(CONFIG_SOUND_SH_DAC_AUDIO_CHANNEL);
}
static void dac_audio_stop(void)
{
dac_audio_stop_timer();
if (mach_is_hp6xx()) {
u16 v = __raw_readw(HD64461_GPADR);
v |= HD64461_GPADR_SPEAKER;
__raw_writew(v, HD64461_GPADR);
}
sh_dac_output(0, CONFIG_SOUND_SH_DAC_AUDIO_CHANNEL);
sh_dac_disable(CONFIG_SOUND_SH_DAC_AUDIO_CHANNEL);
}
static void dac_audio_set_rate(void)
{
wakeups_per_second = ktime_set(0, 1000000000 / rate);
}
static int dac_audio_ioctl(struct inode *inode, struct file *file,
unsigned int cmd, unsigned long arg)
{
int val;
switch (cmd) {
case OSS_GETVERSION:
return put_user(SOUND_VERSION, (int *)arg);
case SNDCTL_DSP_SYNC:
dac_audio_sync();
return 0;
case SNDCTL_DSP_RESET:
dac_audio_reset();
return 0;
case SNDCTL_DSP_GETFMTS:
return put_user(AFMT_U8, (int *)arg);
case SNDCTL_DSP_SETFMT:
return put_user(AFMT_U8, (int *)arg);
case SNDCTL_DSP_NONBLOCK:
spin_lock(&file->f_lock);
file->f_flags |= O_NONBLOCK;
spin_unlock(&file->f_lock);
return 0;
case SNDCTL_DSP_GETCAPS:
return 0;
case SOUND_PCM_WRITE_RATE:
val = *(int *)arg;
if (val > 0) {
rate = val;
dac_audio_set_rate();
}
return put_user(rate, (int *)arg);
case SNDCTL_DSP_STEREO:
return put_user(0, (int *)arg);
case SOUND_PCM_WRITE_CHANNELS:
return put_user(1, (int *)arg);
case SNDCTL_DSP_SETDUPLEX:
return -EINVAL;
case SNDCTL_DSP_PROFILE:
return -EINVAL;
case SNDCTL_DSP_GETBLKSIZE:
return put_user(BUFFER_SIZE, (int *)arg);
case SNDCTL_DSP_SETFRAGMENT:
return 0;
default:
printk(KERN_ERR "sh_dac_audio: unimplemented ioctl=0x%x\n",
cmd);
return -EINVAL;
}
return -EINVAL;
}
static ssize_t dac_audio_write(struct file *file, const char *buf, size_t count,
loff_t * ppos)
{
int free;
int nbytes;
if (!count) {
dac_audio_sync();
return 0;
}
free = buffer_begin - buffer_end;
if (free < 0)
free += BUFFER_SIZE;
if ((free == 0) && (empty))
free = BUFFER_SIZE;
if (count > free)
count = free;
if (buffer_begin > buffer_end) {
if (copy_from_user((void *)buffer_end, buf, count))
return -EFAULT;
buffer_end += count;
} else {
nbytes = data_buffer + BUFFER_SIZE - buffer_end;
if (nbytes > count) {
if (copy_from_user((void *)buffer_end, buf, count))
return -EFAULT;
buffer_end += count;
} else {
if (copy_from_user((void *)buffer_end, buf, nbytes))
return -EFAULT;
if (copy_from_user
((void *)data_buffer, buf + nbytes, count - nbytes))
return -EFAULT;
buffer_end = data_buffer + count - nbytes;
}
}
if (empty) {
empty = 0;
dac_audio_start_timer();
}
return count;
}
static ssize_t dac_audio_read(struct file *file, char *buf, size_t count,
loff_t * ppos)
{
return -EINVAL;
}
static int dac_audio_open(struct inode *inode, struct file *file)
{
if (file->f_mode & FMODE_READ)
return -ENODEV;
if (in_use)
return -EBUSY;
in_use = 1;
dac_audio_start();
return 0;
}
static int dac_audio_release(struct inode *inode, struct file *file)
{
dac_audio_sync();
dac_audio_stop();
in_use = 0;
return 0;
}
const struct file_operations dac_audio_fops = {
.read = dac_audio_read,
.write = dac_audio_write,
.ioctl = dac_audio_ioctl,
.open = dac_audio_open,
.release = dac_audio_release,
};
static enum hrtimer_restart sh_dac_audio_timer(struct hrtimer *handle)
{
if (!empty) {
sh_dac_output(*buffer_begin, CONFIG_SOUND_SH_DAC_AUDIO_CHANNEL);
buffer_begin++;
if (buffer_begin == data_buffer + BUFFER_SIZE)
buffer_begin = data_buffer;
if (buffer_begin == buffer_end)
empty = 1;
}
if (!empty)
hrtimer_start(&hrtimer, wakeups_per_second, HRTIMER_MODE_REL);
return HRTIMER_NORESTART;
}
static int __init dac_audio_init(void)
{
if ((device_major = register_sound_dsp(&dac_audio_fops, -1)) < 0) {
printk(KERN_ERR "Cannot register dsp device");
return device_major;
}
in_use = 0;
data_buffer = kmalloc(BUFFER_SIZE, GFP_KERNEL);
if (data_buffer == NULL)
return -ENOMEM;
dac_audio_reset();
rate = 8000;
dac_audio_set_rate();
/* Today: High Resolution Timer driven DAC playback.
* The timer callback gets called once per sample. Ouch.
*
* Future: A much better approach would be to use the
* SH7720 CMT+DMAC+DAC hardware combination like this:
* - Program sample rate using CMT0 or CMT1
* - Program DMAC to use CMT for timing and output to DAC
* - Play sound using DMAC, let CPU sleep.
* - While at it, rewrite this driver to use ALSA.
*/
hrtimer_init(&hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
hrtimer.function = sh_dac_audio_timer;
return 0;
}
static void __exit dac_audio_exit(void)
{
unregister_sound_dsp(device_major);
kfree((void *)data_buffer);
}
module_init(dac_audio_init);
module_exit(dac_audio_exit);
MODULE_AUTHOR("Andriy Skulysh, askulysh@image.kiev.ua");
MODULE_DESCRIPTION("SH DAC sound driver");
MODULE_LICENSE("GPL");