static DEFINE_RWLOCK(snd_pcm_link_rwlock);
static DECLARE_RWSEM(snd_pcm_link_rwsem);
+/**
+ * snd_pcm_stream_lock - Lock the PCM stream
+ * @substream: PCM substream
+ *
+ * This locks the PCM stream's spinlock or mutex depending on the nonatomic
+ * flag of the given substream. This also takes the global link rw lock
+ * (or rw sem), too, for avoiding the race with linked streams.
+ */
void snd_pcm_stream_lock(struct snd_pcm_substream *substream)
{
if (substream->pcm->nonatomic) {
}
EXPORT_SYMBOL_GPL(snd_pcm_stream_lock);
+/**
+ * snd_pcm_stream_lock - Unlock the PCM stream
+ * @substream: PCM substream
+ *
+ * This unlocks the PCM stream that has been locked via snd_pcm_stream_lock().
+ */
void snd_pcm_stream_unlock(struct snd_pcm_substream *substream)
{
if (substream->pcm->nonatomic) {
}
EXPORT_SYMBOL_GPL(snd_pcm_stream_unlock);
+/**
+ * snd_pcm_stream_lock_irq - Lock the PCM stream
+ * @substream: PCM substream
+ *
+ * This locks the PCM stream like snd_pcm_stream_lock() and disables the local
+ * IRQ (only when nonatomic is false). In nonatomic case, this is identical
+ * as snd_pcm_stream_lock().
+ */
void snd_pcm_stream_lock_irq(struct snd_pcm_substream *substream)
{
if (!substream->pcm->nonatomic)
}
EXPORT_SYMBOL_GPL(snd_pcm_stream_lock_irq);
+/**
+ * snd_pcm_stream_unlock_irq - Unlock the PCM stream
+ * @substream: PCM substream
+ *
+ * This is a counter-part of snd_pcm_stream_lock_irq().
+ */
void snd_pcm_stream_unlock_irq(struct snd_pcm_substream *substream)
{
snd_pcm_stream_unlock(substream);
}
EXPORT_SYMBOL_GPL(_snd_pcm_stream_lock_irqsave);
+/**
+ * snd_pcm_stream_unlock_irqrestore - Unlock the PCM stream
+ * @substream: PCM substream
+ * @flags: irq flags
+ *
+ * This is a counter-part of snd_pcm_stream_lock_irqsave().
+ */
void snd_pcm_stream_unlock_irqrestore(struct snd_pcm_substream *substream,
unsigned long flags)
{
{
struct snd_pcm_substream *s = NULL;
struct snd_pcm_substream *s1;
- int res = 0;
+ int res = 0, depth = 1;
snd_pcm_group_for_each_entry(s, substream) {
if (do_lock && s != substream) {
if (s->pcm->nonatomic)
- mutex_lock_nested(&s->self_group.mutex,
- SINGLE_DEPTH_NESTING);
+ mutex_lock_nested(&s->self_group.mutex, depth);
else
- spin_lock_nested(&s->self_group.lock,
- SINGLE_DEPTH_NESTING);
+ spin_lock_nested(&s->self_group.lock, depth);
+ depth++;
}
res = ops->pre_action(s, state);
if (res < 0)
return res;
}
-/* call in mutex-protected context */
-static int snd_pcm_action_mutex(struct action_ops *ops,
- struct snd_pcm_substream *substream,
- int state)
+/*
+ * Note: call with stream lock
+ */
+static int snd_pcm_action(struct action_ops *ops,
+ struct snd_pcm_substream *substream,
+ int state)
{
int res;
- if (snd_pcm_stream_linked(substream)) {
+ if (!snd_pcm_stream_linked(substream))
+ return snd_pcm_action_single(ops, substream, state);
+
+ if (substream->pcm->nonatomic) {
if (!mutex_trylock(&substream->group->mutex)) {
mutex_unlock(&substream->self_group.mutex);
mutex_lock(&substream->group->mutex);
res = snd_pcm_action_group(ops, substream, state, 1);
mutex_unlock(&substream->group->mutex);
} else {
- res = snd_pcm_action_single(ops, substream, state);
- }
- return res;
-}
-
-/*
- * Note: call with stream lock
- */
-static int snd_pcm_action(struct action_ops *ops,
- struct snd_pcm_substream *substream,
- int state)
-{
- int res;
-
- if (substream->pcm->nonatomic)
- return snd_pcm_action_mutex(ops, substream, state);
-
- if (snd_pcm_stream_linked(substream)) {
if (!spin_trylock(&substream->group->lock)) {
spin_unlock(&substream->self_group.lock);
spin_lock(&substream->group->lock);
}
res = snd_pcm_action_group(ops, substream, state, 1);
spin_unlock(&substream->group->lock);
- } else {
- res = snd_pcm_action_single(ops, substream, state);
}
return res;
}
-static int snd_pcm_action_lock_mutex(struct action_ops *ops,
- struct snd_pcm_substream *substream,
- int state)
-{
- int res;
-
- down_read(&snd_pcm_link_rwsem);
- if (snd_pcm_stream_linked(substream)) {
- mutex_lock(&substream->group->mutex);
- mutex_lock_nested(&substream->self_group.mutex,
- SINGLE_DEPTH_NESTING);
- res = snd_pcm_action_group(ops, substream, state, 1);
- mutex_unlock(&substream->self_group.mutex);
- mutex_unlock(&substream->group->mutex);
- } else {
- mutex_lock(&substream->self_group.mutex);
- res = snd_pcm_action_single(ops, substream, state);
- mutex_unlock(&substream->self_group.mutex);
- }
- up_read(&snd_pcm_link_rwsem);
- return res;
-}
-
/*
* Note: don't use any locks before
*/
{
int res;
- if (substream->pcm->nonatomic)
- return snd_pcm_action_lock_mutex(ops, substream, state);
-
- read_lock_irq(&snd_pcm_link_rwlock);
- if (snd_pcm_stream_linked(substream)) {
- spin_lock(&substream->group->lock);
- spin_lock(&substream->self_group.lock);
- res = snd_pcm_action_group(ops, substream, state, 1);
- spin_unlock(&substream->self_group.lock);
- spin_unlock(&substream->group->lock);
- } else {
- spin_lock(&substream->self_group.lock);
- res = snd_pcm_action_single(ops, substream, state);
- spin_unlock(&substream->self_group.lock);
- }
- read_unlock_irq(&snd_pcm_link_rwlock);
+ snd_pcm_stream_lock_irq(substream);
+ res = snd_pcm_action(ops, substream, state);
+ snd_pcm_stream_unlock_irq(substream);
return res;
}
/*
* mmap the DMA buffer on RAM
*/
+
+/**
+ * snd_pcm_lib_default_mmap - Default PCM data mmap function
+ * @substream: PCM substream
+ * @area: VMA
+ *
+ * This is the default mmap handler for PCM data. When mmap pcm_ops is NULL,
+ * this function is invoked implicitly.
+ */
int snd_pcm_lib_default_mmap(struct snd_pcm_substream *substream,
struct vm_area_struct *area)
{
* mmap the DMA buffer on I/O memory area
*/
#if SNDRV_PCM_INFO_MMAP_IOMEM
+/**
+ * snd_pcm_lib_mmap_iomem - Default PCM data mmap function for I/O mem
+ * @substream: PCM substream
+ * @area: VMA
+ *
+ * When your hardware uses the iomapped pages as the hardware buffer and
+ * wants to mmap it, pass this function as mmap pcm_ops. Note that this
+ * is supposed to work only on limited architectures.
+ */
int snd_pcm_lib_mmap_iomem(struct snd_pcm_substream *substream,
struct vm_area_struct *area)
{
projects / cascardo / linux.git / blobdiff