- 根目录:
- sound
- oss
- midibuf.c
/*
* sound/oss/midibuf.c
*
* Device file manager for /dev/midi#
*/
/*
* Copyright (C) by Hannu Savolainen 1993-1997
*
* OSS/Free for Linux is distributed under the GNU GENERAL PUBLIC LICENSE (GPL)
* Version 2 (June 1991). See the "COPYING" file distributed with this software
* for more info.
*/
/*
* Thomas Sailer : ioctl code reworked (vmalloc/vfree removed)
*/
#include <linux/stddef.h>
#include <linux/kmod.h>
#include <linux/spinlock.h>
#define MIDIBUF_C
#include "sound_config.h"
/*
* Don't make MAX_QUEUE_SIZE larger than 4000
*/
#define MAX_QUEUE_SIZE 4000
static wait_queue_head_t midi_sleeper[MAX_MIDI_DEV];
static wait_queue_head_t input_sleeper[MAX_MIDI_DEV];
struct midi_buf
{
int len, head, tail;
unsigned char queue[MAX_QUEUE_SIZE];
};
struct midi_parms
{
long prech_timeout; /*
* Timeout before the first ch
*/
};
static struct midi_buf *midi_out_buf[MAX_MIDI_DEV] = {NULL};
static struct midi_buf *midi_in_buf[MAX_MIDI_DEV] = {NULL};
static struct midi_parms parms[MAX_MIDI_DEV];
static void midi_poll(unsigned long dummy);
static DEFINE_TIMER(poll_timer, midi_poll, 0, 0);
static volatile int open_devs;
static DEFINE_SPINLOCK(lock);
#define DATA_AVAIL(q) (q->len)
#define SPACE_AVAIL(q) (MAX_QUEUE_SIZE - q->len)
#define QUEUE_BYTE(q, data) \
if (SPACE_AVAIL(q)) \
{ \
unsigned long flags; \
spin_lock_irqsave(&lock, flags); \
q->queue[q->tail] = (data); \
q->len++; q->tail = (q->tail+1) % MAX_QUEUE_SIZE; \
spin_unlock_irqrestore(&lock, flags); \
}
#define REMOVE_BYTE(q, data) \
if (DATA_AVAIL(q)) \
{ \
unsigned long flags; \
spin_lock_irqsave(&lock, flags); \
data = q->queue[q->head]; \
q->len--; q->head = (q->head+1) % MAX_QUEUE_SIZE; \
spin_unlock_irqrestore(&lock, flags); \
}
static void drain_midi_queue(int dev)
{
/*
* Give the Midi driver time to drain its output queues
*/
if (midi_devs[dev]->buffer_status != NULL)
wait_event_interruptible_timeout(midi_sleeper[dev],
!midi_devs[dev]->buffer_status(dev), HZ/10);
}
static void midi_input_intr(int dev, unsigned char data)
{
if (midi_in_buf[dev] == NULL)
return;
if (data == 0xfe) /*
* Active sensing
*/
return; /*
* Ignore
*/
if (SPACE_AVAIL(midi_in_buf[dev])) {
QUEUE_BYTE(midi_in_buf[dev], data);
wake_up(&input_sleeper[dev]);
}
}
static void midi_output_intr(int dev)
{
/*
* Currently NOP
*/
}
static void midi_poll(unsigned long dummy)
{
unsigned long flags;
int dev;
spin_lock_irqsave(&lock, flags);
if (open_devs)
{
for (dev = 0; dev < num_midis; dev++)
if (midi_devs[dev] != NULL && midi_out_buf[dev] != NULL)
{
while (DATA_AVAIL(midi_out_buf[dev]))
{
int ok;
int c = midi_out_buf[dev]->queue[midi_out_buf[dev]->head];
spin_unlock_irqrestore(&lock,flags);/* Give some time to others */
ok = midi_devs[dev]->outputc(dev, c);
spin_lock_irqsave(&lock, flags);
if (!ok)
break;
midi_out_buf[dev]->head = (midi_out_buf[dev]->head + 1) % MAX_QUEUE_SIZE;
midi_out_buf[dev]->len--;
}
if (DATA_AVAIL(midi_out_buf[dev]) < 100)
wake_up(&midi_sleeper[dev]);
}
poll_timer.expires = (1) + jiffies;
add_timer(&poll_timer);
/*
* Come back later
*/
}
spin_unlock_irqrestore(&lock, flags);
}
int MIDIbuf_open(int dev, struct file *file)
{
int mode, err;
dev = dev >> 4;
mode = translate_mode(file);
if (num_midis > MAX_MIDI_DEV)
{
printk(KERN_ERR "midi: Too many midi interfaces\n");
num_midis = MAX_MIDI_DEV;
}
if (dev < 0 || dev >= num_midis || midi_devs[dev] == NULL)
return -ENXIO;
/*
* Interrupts disabled. Be careful
*/
module_put(midi_devs[dev]->owner);
if ((err = midi_devs[dev]->open(dev, mode,
midi_input_intr, midi_output_intr)) < 0)
return err;
parms[dev].prech_timeout = MAX_SCHEDULE_TIMEOUT;
midi_in_buf[dev] = vmalloc(sizeof(struct midi_buf));
if (midi_in_buf[dev] == NULL)
{
printk(KERN_WARNING "midi: Can't allocate buffer\n");
midi_devs[dev]->close(dev);
return -EIO;
}
midi_in_buf[dev]->len = midi_in_buf[dev]->head = midi_in_buf[dev]->tail = 0;
midi_out_buf[dev] = vmalloc(sizeof(struct midi_buf));
if (midi_out_buf[dev] == NULL)
{
printk(KERN_WARNING "midi: Can't allocate buffer\n");
midi_devs[dev]->close(dev);
vfree(midi_in_buf[dev]);
midi_in_buf[dev] = NULL;
return -EIO;
}
midi_out_buf[dev]->len = midi_out_buf[dev]->head = midi_out_buf[dev]->tail = 0;
open_devs++;
init_waitqueue_head(&midi_sleeper[dev]);
init_waitqueue_head(&input_sleeper[dev]);
if (open_devs < 2) /* This was first open */
{
poll_timer.expires = 1 + jiffies;
add_timer(&poll_timer); /* Start polling */
}
return err;
}
void MIDIbuf_release(int dev, struct file *file)
{
int mode;
dev = dev >> 4;
mode = translate_mode(file);
if (dev < 0 || dev >= num_midis || midi_devs[dev] == NULL)
return;
/*
* Wait until the queue is empty
*/
if (mode != OPEN_READ)
{
midi_devs[dev]->outputc(dev, 0xfe); /*
* Active sensing to shut the
* devices
*/
wait_event_interruptible(midi_sleeper[dev],
!DATA_AVAIL(midi_out_buf[dev]));
/*
* Sync
*/
drain_midi_queue(dev); /*
* Ensure the output queues are empty
*/
}
midi_devs[dev]->close(dev);
open_devs--;
if (open_devs == 0)
del_timer_sync(&poll_timer);
vfree(midi_in_buf[dev]);
vfree(midi_out_buf[dev]);
midi_in_buf[dev] = NULL;
midi_out_buf[dev] = NULL;
module_put(midi_devs[dev]->owner);
}
int MIDIbuf_write(int dev, struct file *file, const char __user *buf, int count)
{
int c, n, i;
unsigned char tmp_data;
dev = dev >> 4;
if (!count)
return 0;
c = 0;
while (c < count)
{
n = SPACE_AVAIL(midi_out_buf[dev]);
if (n == 0) { /*
* No space just now.
*/
if (file->f_flags & O_NONBLOCK) {
c = -EAGAIN;
goto out;
}
if (wait_event_interruptible(midi_sleeper[dev],
SPACE_AVAIL(midi_out_buf[dev])))
{
c = -EINTR;
goto out;
}
n = SPACE_AVAIL(midi_out_buf[dev]);
}
if (n > (count - c))
n = count - c;
for (i = 0; i < n; i++)
{
/* BROKE BROKE BROKE - CAN'T DO THIS WITH CLI !! */
/* yes, think the same, so I removed the cli() brackets
QUEUE_BYTE is protected against interrupts */
if (copy_from_user((char *) &tmp_data, &(buf)[c], 1)) {
c = -EFAULT;
goto out;
}
QUEUE_BYTE(midi_out_buf[dev], tmp_data);
c++;
}
}
out:
return c;
}
int MIDIbuf_read(int dev, struct file *file, char __user *buf, int count)
{
int n, c = 0;
unsigned char tmp_data;
dev = dev >> 4;
if (!DATA_AVAIL(midi_in_buf[dev])) { /*
* No data yet, wait
*/
if (file->f_flags & O_NONBLOCK) {
c = -EAGAIN;
goto out;
}
wait_event_interruptible_timeout(input_sleeper[dev],
DATA_AVAIL(midi_in_buf[dev]),
parms[dev].prech_timeout);
if (signal_pending(current))
c = -EINTR; /* The user is getting restless */
}
if (c == 0 && DATA_AVAIL(midi_in_buf[dev])) /*
* Got some bytes
*/
{
n = DATA_AVAIL(midi_in_buf[dev]);
if (n > count)
n = count;
c = 0;
while (c < n)
{
char *fixit;
REMOVE_BYTE(midi_in_buf[dev], tmp_data);
fixit = (char *) &tmp_data;
/* BROKE BROKE BROKE */
/* yes removed the cli() brackets again
should q->len,tail&head be atomic_t? */
if (copy_to_user(&(buf)[c], fixit, 1)) {
c = -EFAULT;
goto out;
}
c++;
}
}
out:
return c;
}
int MIDIbuf_ioctl(int dev, struct file *file,
unsigned int cmd, void __user *arg)
{
int val;
dev = dev >> 4;
if (((cmd >> 8) & 0xff) == 'C')
{
if (midi_devs[dev]->coproc) /* Coprocessor ioctl */
return midi_devs[dev]->coproc->ioctl(midi_devs[dev]->coproc->devc, cmd, arg, 0);
/* printk("/dev/midi%d: No coprocessor for this device\n", dev);*/
return -ENXIO;
}
else
{
switch (cmd)
{
case SNDCTL_MIDI_PRETIME:
if (get_user(val, (int __user *)arg))
return -EFAULT;
if (val < 0)
val = 0;
val = (HZ * val) / 10;
parms[dev].prech_timeout = val;
return put_user(val, (int __user *)arg);
default:
if (!midi_devs[dev]->ioctl)
return -EINVAL;
return midi_devs[dev]->ioctl(dev, cmd, arg);
}
}
}
/* No kernel lock - fine */
unsigned int MIDIbuf_poll(int dev, struct file *file, poll_table * wait)
{
unsigned int mask = 0;
dev = dev >> 4;
/* input */
poll_wait(file, &input_sleeper[dev], wait);
if (DATA_AVAIL(midi_in_buf[dev]))
mask |= POLLIN | POLLRDNORM;
/* output */
poll_wait(file, &midi_sleeper[dev], wait);
if (!SPACE_AVAIL(midi_out_buf[dev]))
mask |= POLLOUT | POLLWRNORM;
return mask;
}
int MIDIbuf_avail(int dev)
{
if (midi_in_buf[dev])
return DATA_AVAIL (midi_in_buf[dev]);
return 0;
}
EXPORT_SYMBOL(MIDIbuf_avail);