// SPDX-License-Identifier: GPL-2.0-only
/*
* fireworks_hwdep.c - a part of driver for Fireworks based devices
*
* Copyright (c) 2013-2014 Takashi Sakamoto
*/
/*
* This codes have five functionalities.
*
* 1.get information about firewire node
* 2.get notification about starting/stopping stream
* 3.lock/unlock streaming
* 4.transmit command of EFW transaction
* 5.receive response of EFW transaction
*
*/
#include "fireworks.h"
static long
hwdep_read_resp_buf(struct snd_efw *efw, char __user *buf, long remained,
loff_t *offset)
{
unsigned int length, till_end, type;
struct snd_efw_transaction *t;
u8 *pull_ptr;
long count = 0;
if (remained < sizeof(type) + sizeof(struct snd_efw_transaction))
return -ENOSPC;
/* data type is SNDRV_FIREWIRE_EVENT_EFW_RESPONSE */
type = SNDRV_FIREWIRE_EVENT_EFW_RESPONSE;
if (copy_to_user(buf, &type, sizeof(type)))
return -EFAULT;
count += sizeof(type);
remained -= sizeof(type);
buf += sizeof(type);
/* write into buffer as many responses as possible */
spin_lock_irq(&efw->lock);
/*
* When another task reaches here during this task's access to user
* space, it picks up current position in buffer and can read the same
* series of responses.
*/
pull_ptr = efw->pull_ptr;
while (efw->push_ptr != pull_ptr) {
t = (struct snd_efw_transaction *)(pull_ptr);
length = be32_to_cpu(t->length) * sizeof(__be32);
/* confirm enough space for this response */
if (remained < length)
break;
/* copy from ring buffer to user buffer */
while (length > 0) {
till_end = snd_efw_resp_buf_size -
(unsigned int)(pull_ptr - efw->resp_buf);
till_end = min_t(unsigned int, length, till_end);
spin_unlock_irq(&efw->lock);
if (copy_to_user(buf, pull_ptr, till_end))
return -EFAULT;
spin_lock_irq(&efw->lock);
pull_ptr += till_end;
if (pull_ptr >= efw->resp_buf + snd_efw_resp_buf_size)
pull_ptr -= snd_efw_resp_buf_size;
length -= till_end;
buf += till_end;
count += till_end;
remained -= till_end;
}
}
/*
* All of tasks can read from the buffer nearly simultaneously, but the
* last position for each task is different depending on the length of
* given buffer. Here, for simplicity, a position of buffer is set by
* the latest task. It's better for a listening application to allow one
* thread to read from the buffer. Unless, each task can read different
* sequence of responses depending on variation of buffer length.
*/
efw->pull_ptr = pull_ptr;
spin_unlock_irq(&efw->lock);
return count;
}
static long
hwdep_read_locked(struct snd_efw *efw, char __user *buf, long count,
loff_t *offset)
{
union snd_firewire_event event = {
.lock_status.type = SNDRV_FIREWIRE_EVENT_LOCK_STATUS,
};
spin_lock_irq(&efw->lock);
event.lock_status.status = (efw->dev_lock_count > 0);
efw->dev_lock_changed = false;
spin_unlock_irq(&efw->lock);
count = min_t(long, count, sizeof(event.lock_status));
if (copy_to_user(buf, &event, count))
return -EFAULT;
return count;
}
static long
hwdep_read(struct snd_hwdep *hwdep, char __user *buf, long count,
loff_t *offset)
{
struct snd_efw *efw = hwdep->private_data;
DEFINE_WAIT(wait);
bool dev_lock_changed;
bool queued;
spin_lock_irq(&efw->lock);
dev_lock_changed = efw->dev_lock_changed;
queued = efw->push_ptr != efw->pull_ptr;
while (!dev_lock_changed && !queued) {
prepare_to_wait(&efw->hwdep_wait, &wait, TASK_INTERRUPTIBLE);
spin_unlock_irq(&efw->lock);
schedule();
finish_wait(&efw->hwdep_wait, &wait);
if (signal_pending(current))
return -ERESTARTSYS;
spin_lock_irq(&efw->lock);
dev_lock_changed = efw->dev_lock_changed;
queued = efw->push_ptr != efw->pull_ptr;
}
spin_unlock_irq(&efw->lock);
if (dev_lock_changed)
count = hwdep_read_locked(efw, buf, count, offset);
else if (queued)
count = hwdep_read_resp_buf(efw, buf, count, offset);
return count;
}
static long
hwdep_write(struct snd_hwdep *hwdep, const char __user *data, long count,
loff_t *offset)
{
struct snd_efw *efw = hwdep->private_data;
u32 seqnum;
u8 *buf;
if (count < sizeof(struct snd_efw_transaction) ||
SND_EFW_RESPONSE_MAXIMUM_BYTES < count)
return -EINVAL;
buf = memdup_user(data, count);
if (IS_ERR(buf))
return PTR_ERR(buf);
/* check seqnum is not for kernel-land */
seqnum = be32_to_cpu(((struct snd_efw_transaction *)buf)->seqnum);
if (seqnum > SND_EFW_TRANSACTION_USER_SEQNUM_MAX) {
count = -EINVAL;
goto end;
}
if (snd_efw_transaction_cmd(efw->unit, buf, count) < 0)
count = -EIO;
end:
kfree(buf);
return count;
}
static __poll_t
hwdep_poll(struct snd_hwdep *hwdep, struct file *file, poll_table *wait)
{
struct snd_efw *efw = hwdep->private_data;
__poll_t events;
poll_wait(file, &efw->hwdep_wait, wait);
spin_lock_irq(&efw->lock);
if (efw->dev_lock_changed || efw->pull_ptr != efw->push_ptr)
events = EPOLLIN | EPOLLRDNORM;
else
events = 0;
spin_unlock_irq(&efw->lock);
return events | EPOLLOUT;
}
static int
hwdep_get_info(struct snd_efw *efw, void __user *arg)
{
struct fw_device *dev = fw_parent_device(efw->unit);
struct snd_firewire_get_info info;
memset(&info, 0, sizeof(info));
info.type = SNDRV_FIREWIRE_TYPE_FIREWORKS;
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_efw *efw)
{
int err;
spin_lock_irq(&efw->lock);
if (efw->dev_lock_count == 0) {
efw->dev_lock_count = -1;
err = 0;
} else {
err = -EBUSY;
}
spin_unlock_irq(&efw->lock);
return err;
}
static int
hwdep_unlock(struct snd_efw *efw)
{
int err;
spin_lock_irq(&efw->lock);
if (efw->dev_lock_count == -1) {
efw->dev_lock_count = 0;
err = 0;
} else {
err = -EBADFD;
}
spin_unlock_irq(&efw->lock);
return err;
}
static int
hwdep_release(struct snd_hwdep *hwdep, struct file *file)
{
struct snd_efw *efw = hwdep->private_data;
spin_lock_irq(&efw->lock);
if (efw->dev_lock_count == -1)
efw->dev_lock_count = 0;
spin_unlock_irq(&efw->lock);
return 0;
}
static int
hwdep_ioctl(struct snd_hwdep *hwdep, struct file *file,
unsigned int cmd, unsigned long arg)
{
struct snd_efw *efw = hwdep->private_data;
switch (cmd) {
case SNDRV_FIREWIRE_IOCTL_GET_INFO:
return hwdep_get_info(efw, (void __user *)arg);
case SNDRV_FIREWIRE_IOCTL_LOCK:
return hwdep_lock(efw);
case SNDRV_FIREWIRE_IOCTL_UNLOCK:
return hwdep_unlock(efw);
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_efw_create_hwdep_device(struct snd_efw *efw)
{
static const struct snd_hwdep_ops ops = {
.read = hwdep_read,
.write = hwdep_write,
.release = hwdep_release,
.poll = hwdep_poll,
.ioctl = hwdep_ioctl,
.ioctl_compat = hwdep_compat_ioctl,
};
struct snd_hwdep *hwdep;
int err;
err = snd_hwdep_new(efw->card, "Fireworks", 0, &hwdep);
if (err < 0)
goto end;
strcpy(hwdep->name, "Fireworks");
hwdep->iface = SNDRV_HWDEP_IFACE_FW_FIREWORKS;
hwdep->ops = ops;
hwdep->private_data = efw;
hwdep->exclusive = true;
end:
return err;
}
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