2021-01-24 17:02:01

by Anton Yakovlev

[permalink] [raw]
Subject: [PATCH v2 9/9] ALSA: virtio: introduce device suspend/resume support

All running PCM substreams are stopped on device suspend and restarted
on device resume.

Signed-off-by: Anton Yakovlev <[email protected]>
---
sound/virtio/virtio_card.c | 54 ++++++++++++++++++++
sound/virtio/virtio_pcm.c | 40 +++++++++++++++
sound/virtio/virtio_pcm.h | 6 +++
sound/virtio/virtio_pcm_ops.c | 93 ++++++++++++++++++++---------------
4 files changed, 154 insertions(+), 39 deletions(-)

diff --git a/sound/virtio/virtio_card.c b/sound/virtio/virtio_card.c
index fabf91fc1c9c..90dadf18d9b0 100644
--- a/sound/virtio/virtio_card.c
+++ b/sound/virtio/virtio_card.c
@@ -491,6 +491,56 @@ static void virtsnd_config_changed(struct virtio_device *vdev)
"sound device configuration was changed\n");
}

+#ifdef CONFIG_PM_SLEEP
+/**
+ * virtsnd_freeze() - Suspend device.
+ * @vdev: VirtIO parent device.
+ *
+ * Context: Any context that permits to sleep.
+ * Return: 0 on success, -errno on failure.
+ */
+static int virtsnd_freeze(struct virtio_device *vdev)
+{
+ struct virtio_snd *snd = vdev->priv;
+
+ virtsnd_disable_vqs(snd);
+
+ vdev->config->reset(vdev);
+ vdev->config->del_vqs(vdev);
+
+ return 0;
+}
+
+/**
+ * virtsnd_restore() - Resume device.
+ * @vdev: VirtIO parent device.
+ *
+ * Context: Any context that permits to sleep.
+ * Return: 0 on success, -errno on failure.
+ */
+static int virtsnd_restore(struct virtio_device *vdev)
+{
+ struct virtio_snd *snd = vdev->priv;
+ int rc;
+
+ rc = virtsnd_find_vqs(snd);
+ if (rc)
+ return rc;
+
+ virtio_device_ready(vdev);
+
+ if (snd->nsubstreams) {
+ rc = virtsnd_pcm_restore(snd);
+ if (rc)
+ return rc;
+ }
+
+ virtsnd_enable_event_vq(snd);
+
+ return 0;
+}
+#endif /* CONFIG_PM_SLEEP */
+
static const struct virtio_device_id id_table[] = {
{ VIRTIO_ID_SOUND, VIRTIO_DEV_ANY_ID },
{ 0 },
@@ -504,6 +554,10 @@ static struct virtio_driver virtsnd_driver = {
.probe = virtsnd_probe,
.remove = virtsnd_remove,
.config_changed = virtsnd_config_changed,
+#ifdef CONFIG_PM_SLEEP
+ .freeze = virtsnd_freeze,
+ .restore = virtsnd_restore,
+#endif
};

static int __init init(void)
diff --git a/sound/virtio/virtio_pcm.c b/sound/virtio/virtio_pcm.c
index 6a1ca6b2c3ca..68d9c6dee13a 100644
--- a/sound/virtio/virtio_pcm.c
+++ b/sound/virtio/virtio_pcm.c
@@ -122,6 +122,7 @@ static int virtsnd_pcm_build_hw(struct virtio_pcm_substream *substream,
SNDRV_PCM_INFO_BATCH |
SNDRV_PCM_INFO_BLOCK_TRANSFER |
SNDRV_PCM_INFO_INTERLEAVED |
+ SNDRV_PCM_INFO_RESUME |
SNDRV_PCM_INFO_PAUSE;

if (!info->channels_min || info->channels_min > info->channels_max) {
@@ -511,6 +512,45 @@ int virtsnd_pcm_build_devs(struct virtio_snd *snd)
return 0;
}

+#ifdef CONFIG_PM_SLEEP
+/**
+ * virtsnd_pcm_restore() - Resume PCM substreams.
+ * @snd: VirtIO sound device.
+ *
+ * Context: Any context that permits to sleep.
+ * Return: 0 on success, -errno on failure.
+ */
+int virtsnd_pcm_restore(struct virtio_snd *snd)
+{
+ unsigned int i;
+
+ for (i = 0; i < snd->nsubstreams; ++i) {
+ struct virtio_pcm_substream *substream = &snd->substreams[i];
+ struct snd_pcm_substream *ksubstream = substream->substream;
+ int rc;
+
+ if (!substream->suspended)
+ continue;
+
+ /*
+ * We restart the substream by executing the standard command
+ * sequence. The START command will be sent from a subsequent
+ * call to the trigger() callback function after the device has
+ * been resumed.
+ */
+ rc = ksubstream->ops->hw_params(ksubstream, NULL);
+ if (rc)
+ return rc;
+
+ rc = ksubstream->ops->prepare(ksubstream);
+ if (rc)
+ return rc;
+ }
+
+ return 0;
+}
+#endif /* CONFIG_PM_SLEEP */
+
/**
* virtsnd_pcm_event() - Handle the PCM device event notification.
* @snd: VirtIO sound device.
diff --git a/sound/virtio/virtio_pcm.h b/sound/virtio/virtio_pcm.h
index a326b921b947..23d0fdd57225 100644
--- a/sound/virtio/virtio_pcm.h
+++ b/sound/virtio/virtio_pcm.h
@@ -41,6 +41,7 @@ struct virtio_pcm_msg;
* @hw_ptr: Substream hardware pointer value in frames [0 ... buffer_size).
* @xfer_enabled: Data transfer state (0 - off, 1 - on).
* @xfer_xrun: Data underflow/overflow state (0 - no xrun, 1 - xrun).
+ * @suspended: Kernel ALSA substream is suspended.
* @msgs: I/O messages.
* @msg_last_enqueued: Index of the last I/O message added to the virtqueue.
* @msg_count: Number of pending I/O messages in the virtqueue.
@@ -60,6 +61,7 @@ struct virtio_pcm_substream {
atomic_t hw_ptr;
atomic_t xfer_enabled;
atomic_t xfer_xrun;
+ bool suspended;
struct virtio_pcm_msg *msgs;
int msg_last_enqueued;
atomic_t msg_count;
@@ -102,6 +104,10 @@ int virtsnd_pcm_parse_cfg(struct virtio_snd *snd);

int virtsnd_pcm_build_devs(struct virtio_snd *snd);

+#ifdef CONFIG_PM_SLEEP
+int virtsnd_pcm_restore(struct virtio_snd *snd);
+#endif /* CONFIG_PM_SLEEP */
+
void virtsnd_pcm_event(struct virtio_snd *snd, struct virtio_snd_event *event);

void virtsnd_pcm_tx_notify_cb(struct virtqueue *vqueue);
diff --git a/sound/virtio/virtio_pcm_ops.c b/sound/virtio/virtio_pcm_ops.c
index 19882777fcd6..0b3c66802325 100644
--- a/sound/virtio/virtio_pcm_ops.c
+++ b/sound/virtio/virtio_pcm_ops.c
@@ -187,6 +187,8 @@ static int virtsnd_pcm_open(struct snd_pcm_substream *substream)
if (!ss)
return -EBADFD;

+ ss->suspended = false;
+
substream->runtime->hw = ss->hw;
substream->private_data = ss;

@@ -241,18 +243,20 @@ static int virtsnd_pcm_hw_params(struct snd_pcm_substream *substream,
int vrate = -1;
int rc;

- /*
- * If we got here after ops->trigger() was called, the queue may
- * still contain messages. In this case, we need to release the
- * substream first.
- */
- if (atomic_read(&ss->msg_count)) {
- rc = virtsnd_pcm_release(ss);
- if (rc) {
- dev_err(&vdev->dev,
- "SID %u: invalid I/O queue state\n",
- ss->sid);
- return rc;
+ if (!ss->suspended) {
+ /*
+ * If we got here after ops->trigger() was called, the queue may
+ * still contain messages. In this case, we need to release the
+ * substream first.
+ */
+ if (atomic_read(&ss->msg_count)) {
+ rc = virtsnd_pcm_release(ss);
+ if (rc) {
+ dev_err(&vdev->dev,
+ "SID %u: invalid I/O queue state\n",
+ ss->sid);
+ return rc;
+ }
}
}

@@ -383,37 +387,41 @@ static int virtsnd_pcm_hw_free(struct snd_pcm_substream *substream)
static int virtsnd_pcm_prepare(struct snd_pcm_substream *substream)
{
struct virtio_pcm_substream *ss = snd_pcm_substream_chip(substream);
- struct virtio_snd_queue *queue = virtsnd_pcm_queue(ss);
struct virtio_snd_msg *msg;
unsigned long flags;
int rc;

- /*
- * If we got here after ops->trigger() was called, the queue may
- * still contain messages. In this case, we need to reset the
- * substream first.
- */
- if (atomic_read(&ss->msg_count)) {
- rc = virtsnd_pcm_hw_params(substream, NULL);
- if (rc)
- return rc;
- }
-
- spin_lock_irqsave(&queue->lock, flags);
- ss->msg_last_enqueued = -1;
- spin_unlock_irqrestore(&queue->lock, flags);
+ if (!ss->suspended) {
+ struct virtio_snd_queue *queue = virtsnd_pcm_queue(ss);
+
+ /*
+ * If we got here after ops->trigger() was called, the queue may
+ * still contain messages. In this case, we need to reset the
+ * substream first.
+ */
+ if (atomic_read(&ss->msg_count)) {
+ rc = virtsnd_pcm_hw_params(substream, NULL);
+ if (rc)
+ return rc;
+ }

- /*
- * Since I/O messages are asynchronous, they can be completed
- * when the runtime structure no longer exists. Since each
- * completion implies incrementing the hw_ptr, we cache all the
- * current values needed to compute the new hw_ptr value.
- */
- ss->frame_bytes = substream->runtime->frame_bits >> 3;
- ss->period_size = substream->runtime->period_size;
- ss->buffer_size = substream->runtime->buffer_size;
+ spin_lock_irqsave(&queue->lock, flags);
+ ss->msg_last_enqueued = -1;
+ spin_unlock_irqrestore(&queue->lock, flags);
+
+ /*
+ * Since I/O messages are asynchronous, they can be completed
+ * when the runtime structure no longer exists. Since each
+ * completion implies incrementing the hw_ptr, we cache all the
+ * current values needed to compute the new hw_ptr value.
+ */
+ ss->frame_bytes = substream->runtime->frame_bits >> 3;
+ ss->period_size = substream->runtime->period_size;
+ ss->buffer_size = substream->runtime->buffer_size;
+
+ atomic_set(&ss->hw_ptr, 0);
+ }

- atomic_set(&ss->hw_ptr, 0);
atomic_set(&ss->xfer_xrun, 0);
atomic_set(&ss->msg_count, 0);

@@ -446,9 +454,12 @@ static int virtsnd_pcm_trigger(struct snd_pcm_substream *substream, int command)

switch (command) {
case SNDRV_PCM_TRIGGER_START:
- case SNDRV_PCM_TRIGGER_PAUSE_RELEASE: {
+ case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
+ case SNDRV_PCM_TRIGGER_RESUME: {
int rc;

+ ss->suspended = false;
+
spin_lock(&queue->lock);
rc = virtsnd_pcm_msg_send(ss);
spin_unlock(&queue->lock);
@@ -465,9 +476,13 @@ static int virtsnd_pcm_trigger(struct snd_pcm_substream *substream, int command)
return virtsnd_ctl_msg_send(snd, msg);
}
case SNDRV_PCM_TRIGGER_STOP:
- case SNDRV_PCM_TRIGGER_PAUSE_PUSH: {
+ case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
+ case SNDRV_PCM_TRIGGER_SUSPEND: {
atomic_set(&ss->xfer_enabled, 0);

+ if (command == SNDRV_PCM_TRIGGER_SUSPEND)
+ ss->suspended = true;
+
msg = virtsnd_pcm_ctl_msg_alloc(ss, VIRTIO_SND_R_PCM_STOP,
GFP_ATOMIC);
if (IS_ERR(msg))
--
2.30.0