swh:1:snp:32555a3fd8878f019c2ebd6c964bc1edcaeff337
Tip revision: 7e57714cd0ad2d5bb90e50b5096a0e671dec1ef3 authored by Linus Torvalds on 27 February 2022, 22:36:33 UTC
Linux 5.17-rc6
Linux 5.17-rc6
Tip revision: 7e57714
tascam-hwdep.c
// SPDX-License-Identifier: GPL-2.0-only
/*
* tascam-hwdep.c - a part of driver for TASCAM FireWire series
*
* Copyright (c) 2015 Takashi Sakamoto
*/
/*
* This codes give three functionality.
*
* 1.get firewire node information
* 2.get notification about starting/stopping stream
* 3.lock/unlock stream
*/
#include "tascam.h"
static long tscm_hwdep_read_locked(struct snd_tscm *tscm, char __user *buf,
long count, loff_t *offset)
__releases(&tscm->lock)
{
struct snd_firewire_event_lock_status event = {
.type = SNDRV_FIREWIRE_EVENT_LOCK_STATUS,
};
event.status = (tscm->dev_lock_count > 0);
tscm->dev_lock_changed = false;
count = min_t(long, count, sizeof(event));
spin_unlock_irq(&tscm->lock);
if (copy_to_user(buf, &event, count))
return -EFAULT;
return count;
}
static long tscm_hwdep_read_queue(struct snd_tscm *tscm, char __user *buf,
long remained, loff_t *offset)
__releases(&tscm->lock)
{
char __user *pos = buf;
unsigned int type = SNDRV_FIREWIRE_EVENT_TASCAM_CONTROL;
struct snd_firewire_tascam_change *entries = tscm->queue;
long count;
// At least, one control event can be copied.
if (remained < sizeof(type) + sizeof(*entries)) {
spin_unlock_irq(&tscm->lock);
return -EINVAL;
}
// Copy the type field later.
count = sizeof(type);
remained -= sizeof(type);
pos += sizeof(type);
while (true) {
unsigned int head_pos;
unsigned int tail_pos;
unsigned int length;
if (tscm->pull_pos == tscm->push_pos)
break;
else if (tscm->pull_pos < tscm->push_pos)
tail_pos = tscm->push_pos;
else
tail_pos = SND_TSCM_QUEUE_COUNT;
head_pos = tscm->pull_pos;
length = (tail_pos - head_pos) * sizeof(*entries);
if (remained < length)
length = rounddown(remained, sizeof(*entries));
if (length == 0)
break;
spin_unlock_irq(&tscm->lock);
if (copy_to_user(pos, &entries[head_pos], length))
return -EFAULT;
spin_lock_irq(&tscm->lock);
tscm->pull_pos = tail_pos % SND_TSCM_QUEUE_COUNT;
count += length;
remained -= length;
pos += length;
}
spin_unlock_irq(&tscm->lock);
if (copy_to_user(buf, &type, sizeof(type)))
return -EFAULT;
return count;
}
static long hwdep_read(struct snd_hwdep *hwdep, char __user *buf, long count,
loff_t *offset)
{
struct snd_tscm *tscm = hwdep->private_data;
DEFINE_WAIT(wait);
spin_lock_irq(&tscm->lock);
while (!tscm->dev_lock_changed && tscm->push_pos == tscm->pull_pos) {
prepare_to_wait(&tscm->hwdep_wait, &wait, TASK_INTERRUPTIBLE);
spin_unlock_irq(&tscm->lock);
schedule();
finish_wait(&tscm->hwdep_wait, &wait);
if (signal_pending(current))
return -ERESTARTSYS;
spin_lock_irq(&tscm->lock);
}
// NOTE: The acquired lock should be released in callee side.
if (tscm->dev_lock_changed) {
count = tscm_hwdep_read_locked(tscm, buf, count, offset);
} else if (tscm->push_pos != tscm->pull_pos) {
count = tscm_hwdep_read_queue(tscm, buf, count, offset);
} else {
spin_unlock_irq(&tscm->lock);
count = 0;
}
return count;
}
static __poll_t hwdep_poll(struct snd_hwdep *hwdep, struct file *file,
poll_table *wait)
{
struct snd_tscm *tscm = hwdep->private_data;
__poll_t events;
poll_wait(file, &tscm->hwdep_wait, wait);
spin_lock_irq(&tscm->lock);
if (tscm->dev_lock_changed || tscm->push_pos != tscm->pull_pos)
events = EPOLLIN | EPOLLRDNORM;
else
events = 0;
spin_unlock_irq(&tscm->lock);
return events;
}
static int hwdep_get_info(struct snd_tscm *tscm, void __user *arg)
{
struct fw_device *dev = fw_parent_device(tscm->unit);
struct snd_firewire_get_info info;
memset(&info, 0, sizeof(info));
info.type = SNDRV_FIREWIRE_TYPE_TASCAM;
info.card = dev->card->index;
*(__be32 *)&info.guid[0] = cpu_to_be32(dev->config_rom[3]);
*(__be32 *)&info.guid[4] = cpu_to_be32(dev->config_rom[4]);
strscpy(info.device_name, dev_name(&dev->device),
sizeof(info.device_name));
if (copy_to_user(arg, &info, sizeof(info)))
return -EFAULT;
return 0;
}
static int hwdep_lock(struct snd_tscm *tscm)
{
int err;
spin_lock_irq(&tscm->lock);
if (tscm->dev_lock_count == 0) {
tscm->dev_lock_count = -1;
err = 0;
} else {
err = -EBUSY;
}
spin_unlock_irq(&tscm->lock);
return err;
}
static int hwdep_unlock(struct snd_tscm *tscm)
{
int err;
spin_lock_irq(&tscm->lock);
if (tscm->dev_lock_count == -1) {
tscm->dev_lock_count = 0;
err = 0;
} else {
err = -EBADFD;
}
spin_unlock_irq(&tscm->lock);
return err;
}
static int tscm_hwdep_state(struct snd_tscm *tscm, void __user *arg)
{
if (copy_to_user(arg, tscm->state, sizeof(tscm->state)))
return -EFAULT;
return 0;
}
static int hwdep_release(struct snd_hwdep *hwdep, struct file *file)
{
struct snd_tscm *tscm = hwdep->private_data;
spin_lock_irq(&tscm->lock);
if (tscm->dev_lock_count == -1)
tscm->dev_lock_count = 0;
spin_unlock_irq(&tscm->lock);
return 0;
}
static int hwdep_ioctl(struct snd_hwdep *hwdep, struct file *file,
unsigned int cmd, unsigned long arg)
{
struct snd_tscm *tscm = hwdep->private_data;
switch (cmd) {
case SNDRV_FIREWIRE_IOCTL_GET_INFO:
return hwdep_get_info(tscm, (void __user *)arg);
case SNDRV_FIREWIRE_IOCTL_LOCK:
return hwdep_lock(tscm);
case SNDRV_FIREWIRE_IOCTL_UNLOCK:
return hwdep_unlock(tscm);
case SNDRV_FIREWIRE_IOCTL_TASCAM_STATE:
return tscm_hwdep_state(tscm, (void __user *)arg);
default:
return -ENOIOCTLCMD;
}
}
#ifdef CONFIG_COMPAT
static int hwdep_compat_ioctl(struct snd_hwdep *hwdep, struct file *file,
unsigned int cmd, unsigned long arg)
{
return hwdep_ioctl(hwdep, file, cmd,
(unsigned long)compat_ptr(arg));
}
#else
#define hwdep_compat_ioctl NULL
#endif
int snd_tscm_create_hwdep_device(struct snd_tscm *tscm)
{
static const struct snd_hwdep_ops ops = {
.read = hwdep_read,
.release = hwdep_release,
.poll = hwdep_poll,
.ioctl = hwdep_ioctl,
.ioctl_compat = hwdep_compat_ioctl,
};
struct snd_hwdep *hwdep;
int err;
err = snd_hwdep_new(tscm->card, "Tascam", 0, &hwdep);
if (err < 0)
return err;
strcpy(hwdep->name, "Tascam");
hwdep->iface = SNDRV_HWDEP_IFACE_FW_TASCAM;
hwdep->ops = ops;
hwdep->private_data = tscm;
hwdep->exclusive = true;
tscm->hwdep = hwdep;
return err;
}