[PATCH v6 6/9] ALSA: virtio: PCM substream operators
Anton Yakovlev
anton.yakovlev at opensynergy.com
Sat Feb 27 09:59:53 CET 2021
Introduce the operators required for the operation of substreams.
Signed-off-by: Anton Yakovlev <anton.yakovlev at opensynergy.com>
---
sound/virtio/Makefile | 3 +-
sound/virtio/virtio_pcm.c | 2 +
sound/virtio/virtio_pcm.h | 4 +
sound/virtio/virtio_pcm_ops.c | 453 ++++++++++++++++++++++++++++++++++
4 files changed, 461 insertions(+), 1 deletion(-)
create mode 100644 sound/virtio/virtio_pcm_ops.c
diff --git a/sound/virtio/Makefile b/sound/virtio/Makefile
index 626af3cc3ed7..34493226793f 100644
--- a/sound/virtio/Makefile
+++ b/sound/virtio/Makefile
@@ -6,5 +6,6 @@ virtio_snd-objs := \
virtio_card.o \
virtio_ctl_msg.o \
virtio_pcm.o \
- virtio_pcm_msg.o
+ virtio_pcm_msg.o \
+ virtio_pcm_ops.o
diff --git a/sound/virtio/virtio_pcm.c b/sound/virtio/virtio_pcm.c
index 3cfd3520a9c0..3605151860f2 100644
--- a/sound/virtio/virtio_pcm.c
+++ b/sound/virtio/virtio_pcm.c
@@ -454,6 +454,8 @@ int virtsnd_pcm_build_devs(struct virtio_snd *snd)
for (kss = ks->substream; kss; kss = kss->next)
vs->substreams[kss->number]->substream = kss;
+
+ snd_pcm_set_ops(vpcm->pcm, i, &virtsnd_pcm_ops);
}
snd_pcm_set_managed_buffer_all(vpcm->pcm,
diff --git a/sound/virtio/virtio_pcm.h b/sound/virtio/virtio_pcm.h
index 7af41cad4e8f..55dfb19d14b3 100644
--- a/sound/virtio/virtio_pcm.h
+++ b/sound/virtio/virtio_pcm.h
@@ -28,6 +28,7 @@ struct virtio_pcm_msg;
* @hw_ptr: Substream hardware pointer value in bytes [0 ... buffer_bytes).
* @xfer_enabled: Data transfer state (0 - off, 1 - on).
* @xfer_xrun: Data underflow/overflow state (0 - no xrun, 1 - xrun).
+ * @release: True if the substream must be released on the device side.
* @msgs: Allocated I/O messages.
* @nmsgs: Number of allocated I/O messages.
* @msg_last_enqueued: Index of the last I/O message added to the virtqueue.
@@ -47,6 +48,7 @@ struct virtio_pcm_substream {
size_t hw_ptr;
bool xfer_enabled;
bool xfer_xrun;
+ bool release;
struct virtio_pcm_msg **msgs;
unsigned int nmsgs;
int msg_last_enqueued;
@@ -78,6 +80,8 @@ struct virtio_pcm {
struct virtio_pcm_stream streams[SNDRV_PCM_STREAM_LAST + 1];
};
+extern const struct snd_pcm_ops virtsnd_pcm_ops;
+
int virtsnd_pcm_validate(struct virtio_device *vdev);
int virtsnd_pcm_parse_cfg(struct virtio_snd *snd);
diff --git a/sound/virtio/virtio_pcm_ops.c b/sound/virtio/virtio_pcm_ops.c
new file mode 100644
index 000000000000..d02d79bd94f3
--- /dev/null
+++ b/sound/virtio/virtio_pcm_ops.c
@@ -0,0 +1,453 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * virtio-snd: Virtio sound device
+ * Copyright (C) 2021 OpenSynergy GmbH
+ */
+#include <sound/pcm_params.h>
+
+#include "virtio_card.h"
+
+/*
+ * I/O messages lifetime
+ * ---------------------
+ *
+ * Allocation:
+ * Messages are initially allocated in the ops->hw_params() after the size and
+ * number of periods have been successfully negotiated.
+ *
+ * Freeing:
+ * Messages can be safely freed after the queue has been successfully flushed
+ * (RELEASE command in the ops->sync_stop()) and the ops->hw_free() has been
+ * called.
+ *
+ * When the substream stops, the ops->sync_stop() waits until the device has
+ * completed all pending messages. This wait can be interrupted either by a
+ * signal or due to a timeout. In this case, the device can still access
+ * messages even after calling ops->hw_free(). It can also issue an interrupt,
+ * and the interrupt handler will also try to access message structures.
+ *
+ * Therefore, freeing of already allocated messages occurs:
+ *
+ * - in ops->hw_params(), if this operator was called several times in a row,
+ * or if ops->hw_free() failed to free messages previously;
+ *
+ * - in ops->hw_free(), if the queue has been successfully flushed;
+ *
+ * - in dev->release().
+ */
+
+/* Map for converting ALSA format to VirtIO format. */
+struct virtsnd_a2v_format {
+ snd_pcm_format_t alsa_bit;
+ unsigned int vio_bit;
+};
+
+static const struct virtsnd_a2v_format g_a2v_format_map[] = {
+ { SNDRV_PCM_FORMAT_IMA_ADPCM, VIRTIO_SND_PCM_FMT_IMA_ADPCM },
+ { SNDRV_PCM_FORMAT_MU_LAW, VIRTIO_SND_PCM_FMT_MU_LAW },
+ { SNDRV_PCM_FORMAT_A_LAW, VIRTIO_SND_PCM_FMT_A_LAW },
+ { SNDRV_PCM_FORMAT_S8, VIRTIO_SND_PCM_FMT_S8 },
+ { SNDRV_PCM_FORMAT_U8, VIRTIO_SND_PCM_FMT_U8 },
+ { SNDRV_PCM_FORMAT_S16_LE, VIRTIO_SND_PCM_FMT_S16 },
+ { SNDRV_PCM_FORMAT_U16_LE, VIRTIO_SND_PCM_FMT_U16 },
+ { SNDRV_PCM_FORMAT_S18_3LE, VIRTIO_SND_PCM_FMT_S18_3 },
+ { SNDRV_PCM_FORMAT_U18_3LE, VIRTIO_SND_PCM_FMT_U18_3 },
+ { SNDRV_PCM_FORMAT_S20_3LE, VIRTIO_SND_PCM_FMT_S20_3 },
+ { SNDRV_PCM_FORMAT_U20_3LE, VIRTIO_SND_PCM_FMT_U20_3 },
+ { SNDRV_PCM_FORMAT_S24_3LE, VIRTIO_SND_PCM_FMT_S24_3 },
+ { SNDRV_PCM_FORMAT_U24_3LE, VIRTIO_SND_PCM_FMT_U24_3 },
+ { SNDRV_PCM_FORMAT_S20_LE, VIRTIO_SND_PCM_FMT_S20 },
+ { SNDRV_PCM_FORMAT_U20_LE, VIRTIO_SND_PCM_FMT_U20 },
+ { SNDRV_PCM_FORMAT_S24_LE, VIRTIO_SND_PCM_FMT_S24 },
+ { SNDRV_PCM_FORMAT_U24_LE, VIRTIO_SND_PCM_FMT_U24 },
+ { SNDRV_PCM_FORMAT_S32_LE, VIRTIO_SND_PCM_FMT_S32 },
+ { SNDRV_PCM_FORMAT_U32_LE, VIRTIO_SND_PCM_FMT_U32 },
+ { SNDRV_PCM_FORMAT_FLOAT_LE, VIRTIO_SND_PCM_FMT_FLOAT },
+ { SNDRV_PCM_FORMAT_FLOAT64_LE, VIRTIO_SND_PCM_FMT_FLOAT64 },
+ { SNDRV_PCM_FORMAT_DSD_U8, VIRTIO_SND_PCM_FMT_DSD_U8 },
+ { SNDRV_PCM_FORMAT_DSD_U16_LE, VIRTIO_SND_PCM_FMT_DSD_U16 },
+ { SNDRV_PCM_FORMAT_DSD_U32_LE, VIRTIO_SND_PCM_FMT_DSD_U32 },
+ { SNDRV_PCM_FORMAT_IEC958_SUBFRAME_LE,
+ VIRTIO_SND_PCM_FMT_IEC958_SUBFRAME }
+};
+
+/* Map for converting ALSA frame rate to VirtIO frame rate. */
+struct virtsnd_a2v_rate {
+ unsigned int rate;
+ unsigned int vio_bit;
+};
+
+static const struct virtsnd_a2v_rate g_a2v_rate_map[] = {
+ { 5512, VIRTIO_SND_PCM_RATE_5512 },
+ { 8000, VIRTIO_SND_PCM_RATE_8000 },
+ { 11025, VIRTIO_SND_PCM_RATE_11025 },
+ { 16000, VIRTIO_SND_PCM_RATE_16000 },
+ { 22050, VIRTIO_SND_PCM_RATE_22050 },
+ { 32000, VIRTIO_SND_PCM_RATE_32000 },
+ { 44100, VIRTIO_SND_PCM_RATE_44100 },
+ { 48000, VIRTIO_SND_PCM_RATE_48000 },
+ { 64000, VIRTIO_SND_PCM_RATE_64000 },
+ { 88200, VIRTIO_SND_PCM_RATE_88200 },
+ { 96000, VIRTIO_SND_PCM_RATE_96000 },
+ { 176400, VIRTIO_SND_PCM_RATE_176400 },
+ { 192000, VIRTIO_SND_PCM_RATE_192000 }
+};
+
+static int virtsnd_pcm_sync_stop(struct snd_pcm_substream *substream);
+
+/**
+ * virtsnd_pcm_open() - Open the PCM substream.
+ * @substream: Kernel ALSA substream.
+ *
+ * Context: Process context.
+ * Return: 0 on success, -errno on failure.
+ */
+static int virtsnd_pcm_open(struct snd_pcm_substream *substream)
+{
+ struct virtio_pcm *vpcm = snd_pcm_substream_chip(substream);
+ struct virtio_pcm_stream *vs = &vpcm->streams[substream->stream];
+ struct virtio_pcm_substream *vss = vs->substreams[substream->number];
+
+ substream->runtime->hw = vss->hw;
+ substream->private_data = vss;
+
+ snd_pcm_hw_constraint_integer(substream->runtime,
+ SNDRV_PCM_HW_PARAM_PERIODS);
+
+ /*
+ * If the substream has already been used, then the I/O queue may be in
+ * an invalid state. Just in case, we do a check and try to return the
+ * queue to its original state, if necessary.
+ */
+ vss->release = !!virtsnd_pcm_msg_pending_num(vss);
+
+ return virtsnd_pcm_sync_stop(substream);
+}
+
+/**
+ * virtsnd_pcm_close() - Close the PCM substream.
+ * @substream: Kernel ALSA substream.
+ *
+ * Context: Process context.
+ * Return: 0.
+ */
+static int virtsnd_pcm_close(struct snd_pcm_substream *substream)
+{
+ return 0;
+}
+
+/**
+ * virtsnd_pcm_hw_params() - Set the parameters of the PCM substream.
+ * @substream: Kernel ALSA substream.
+ * @hw_params: Hardware parameters (can be NULL).
+ *
+ * The function can be called both from the upper level (in this case,
+ * @hw_params is not NULL) or from the driver itself (in this case, @hw_params
+ * is NULL, and the parameter values are taken from the runtime structure).
+ *
+ * Context: Process context.
+ * Return: 0 on success, -errno on failure.
+ */
+static int virtsnd_pcm_hw_params(struct snd_pcm_substream *substream,
+ struct snd_pcm_hw_params *hw_params)
+{
+ struct snd_pcm_runtime *runtime = substream->runtime;
+ struct virtio_pcm_substream *vss = snd_pcm_substream_chip(substream);
+ struct virtio_device *vdev = vss->snd->vdev;
+ struct virtio_snd_msg *msg;
+ struct virtio_snd_pcm_set_params *request;
+ snd_pcm_format_t format;
+ unsigned int channels;
+ unsigned int rate;
+ unsigned int buffer_bytes;
+ unsigned int period_bytes;
+ unsigned int periods;
+ unsigned int i;
+ int vformat = -1;
+ int vrate = -1;
+ int rc;
+
+ if (virtsnd_pcm_msg_pending_num(vss)) {
+ dev_err(&vdev->dev, "SID %u: invalid I/O queue state\n",
+ vss->sid);
+ return -EBADFD;
+ }
+
+ /* Set hardware parameters in device */
+ if (hw_params) {
+ format = params_format(hw_params);
+ channels = params_channels(hw_params);
+ rate = params_rate(hw_params);
+ buffer_bytes = params_buffer_bytes(hw_params);
+ period_bytes = params_period_bytes(hw_params);
+ periods = params_periods(hw_params);
+ } else {
+ format = runtime->format;
+ channels = runtime->channels;
+ rate = runtime->rate;
+ buffer_bytes = frames_to_bytes(runtime, runtime->buffer_size);
+ period_bytes = frames_to_bytes(runtime, runtime->period_size);
+ periods = runtime->periods;
+ }
+
+ for (i = 0; i < ARRAY_SIZE(g_a2v_format_map); ++i)
+ if (g_a2v_format_map[i].alsa_bit == format) {
+ vformat = g_a2v_format_map[i].vio_bit;
+
+ break;
+ }
+
+ for (i = 0; i < ARRAY_SIZE(g_a2v_rate_map); ++i)
+ if (g_a2v_rate_map[i].rate == rate) {
+ vrate = g_a2v_rate_map[i].vio_bit;
+
+ break;
+ }
+
+ if (vformat == -1 || vrate == -1)
+ return -EINVAL;
+
+ msg = virtsnd_pcm_ctl_msg_alloc(vss, VIRTIO_SND_R_PCM_SET_PARAMS,
+ GFP_KERNEL);
+ if (!msg)
+ return -ENOMEM;
+
+ request = virtsnd_ctl_msg_request(msg);
+ request->buffer_bytes = cpu_to_le32(buffer_bytes);
+ request->period_bytes = cpu_to_le32(period_bytes);
+ request->channels = channels;
+ request->format = vformat;
+ request->rate = vrate;
+
+ if (vss->features & (1U << VIRTIO_SND_PCM_F_MSG_POLLING))
+ request->features |=
+ cpu_to_le32(1U << VIRTIO_SND_PCM_F_MSG_POLLING);
+
+ if (vss->features & (1U << VIRTIO_SND_PCM_F_EVT_XRUNS))
+ request->features |=
+ cpu_to_le32(1U << VIRTIO_SND_PCM_F_EVT_XRUNS);
+
+ rc = virtsnd_ctl_msg_send_sync(vss->snd, msg);
+ if (rc)
+ return rc;
+
+ /* Free previously allocated messages (if any). */
+ virtsnd_pcm_msg_free(vss);
+
+ return virtsnd_pcm_msg_alloc(vss, periods, period_bytes);
+}
+
+/**
+ * virtsnd_pcm_hw_free() - Reset the parameters of the PCM substream.
+ * @substream: Kernel ALSA substream.
+ *
+ * Context: Process context.
+ * Return: 0
+ */
+static int virtsnd_pcm_hw_free(struct snd_pcm_substream *substream)
+{
+ struct virtio_pcm_substream *vss = snd_pcm_substream_chip(substream);
+
+ /* If the queue is flushed, we can safely free the messages here. */
+ if (!virtsnd_pcm_msg_pending_num(vss))
+ virtsnd_pcm_msg_free(vss);
+
+ return 0;
+}
+
+/**
+ * virtsnd_pcm_prepare() - Prepare the PCM substream.
+ * @substream: Kernel ALSA substream.
+ *
+ * The function can be called both from the upper level or from the driver
+ * itself.
+ *
+ * Context: Process context.
+ * Return: 0 on success, -errno on failure.
+ */
+static int virtsnd_pcm_prepare(struct snd_pcm_substream *substream)
+{
+ struct virtio_pcm_substream *vss = snd_pcm_substream_chip(substream);
+ struct virtio_device *vdev = vss->snd->vdev;
+ struct virtio_snd_msg *msg;
+
+ if (virtsnd_pcm_msg_pending_num(vss)) {
+ dev_err(&vdev->dev, "SID %u: invalid I/O queue state\n",
+ vss->sid);
+ return -EBADFD;
+ }
+
+ vss->buffer_bytes = snd_pcm_lib_buffer_bytes(substream);
+ vss->hw_ptr = 0;
+ vss->xfer_xrun = false;
+ vss->msg_last_enqueued = -1;
+ vss->msg_count = 0;
+
+ msg = virtsnd_pcm_ctl_msg_alloc(vss, VIRTIO_SND_R_PCM_PREPARE,
+ GFP_KERNEL);
+ if (!msg)
+ return -ENOMEM;
+
+ return virtsnd_ctl_msg_send_sync(vss->snd, msg);
+}
+
+/**
+ * virtsnd_pcm_trigger() - Process command for the PCM substream.
+ * @substream: Kernel ALSA substream.
+ * @command: Substream command (SNDRV_PCM_TRIGGER_XXX).
+ *
+ * Context: Any context. Takes and releases the VirtIO substream spinlock.
+ * May take and release the tx/rx queue spinlock.
+ * Return: 0 on success, -errno on failure.
+ */
+static int virtsnd_pcm_trigger(struct snd_pcm_substream *substream, int command)
+{
+ struct virtio_pcm_substream *vss = snd_pcm_substream_chip(substream);
+ struct virtio_snd *snd = vss->snd;
+ struct virtio_snd_msg *msg;
+ unsigned long flags;
+ int rc;
+
+ switch (command) {
+ case SNDRV_PCM_TRIGGER_START:
+ case SNDRV_PCM_TRIGGER_PAUSE_RELEASE: {
+ struct virtio_snd_queue *queue = virtsnd_pcm_queue(vss);
+
+ spin_lock_irqsave(&queue->lock, flags);
+ spin_lock(&vss->lock);
+ rc = virtsnd_pcm_msg_send(vss);
+ if (!rc)
+ vss->xfer_enabled = true;
+ spin_unlock(&vss->lock);
+ spin_unlock_irqrestore(&queue->lock, flags);
+ if (rc)
+ return rc;
+
+ msg = virtsnd_pcm_ctl_msg_alloc(vss, VIRTIO_SND_R_PCM_START,
+ GFP_KERNEL);
+ if (!msg) {
+ spin_lock_irqsave(&vss->lock, flags);
+ vss->xfer_enabled = false;
+ spin_unlock_irqrestore(&vss->lock, flags);
+
+ return -ENOMEM;
+ }
+
+ return virtsnd_ctl_msg_send_sync(snd, msg);
+ }
+ case SNDRV_PCM_TRIGGER_STOP:
+ case SNDRV_PCM_TRIGGER_PAUSE_PUSH: {
+ spin_lock_irqsave(&vss->lock, flags);
+ vss->xfer_enabled = false;
+ spin_unlock_irqrestore(&vss->lock, flags);
+
+ /*
+ * The substream needs to be released on the device side only
+ * when it is completely stopped.
+ */
+ vss->release = (command == SNDRV_PCM_TRIGGER_STOP);
+
+ /*
+ * The STOP command can be issued in an atomic context after
+ * the drain is complete. Therefore, in general, we cannot sleep
+ * here.
+ */
+ msg = virtsnd_pcm_ctl_msg_alloc(vss, VIRTIO_SND_R_PCM_STOP,
+ GFP_ATOMIC);
+ if (!msg)
+ return -ENOMEM;
+
+ return virtsnd_ctl_msg_send_async(snd, msg);
+ }
+ default: {
+ return -EINVAL;
+ }
+ }
+}
+
+/**
+ * virtsnd_pcm_sync_stop() - Synchronous PCM substream stop.
+ * @substream: Kernel ALSA substream.
+ *
+ * The function can be called both from the upper level or from the driver
+ * itself.
+ *
+ * Context: Process context. Takes and releases the VirtIO substream spinlock.
+ * Return: 0 on success, -errno on failure.
+ */
+static int virtsnd_pcm_sync_stop(struct snd_pcm_substream *substream)
+{
+ struct virtio_pcm_substream *vss = snd_pcm_substream_chip(substream);
+ struct virtio_snd *snd = vss->snd;
+ struct virtio_snd_msg *msg;
+ unsigned int js = msecs_to_jiffies(msg_timeout_ms);
+ int rc;
+
+ if (!vss->release)
+ return 0;
+
+ msg = virtsnd_pcm_ctl_msg_alloc(vss, VIRTIO_SND_R_PCM_RELEASE,
+ GFP_KERNEL);
+ if (!msg)
+ return -ENOMEM;
+
+ rc = virtsnd_ctl_msg_send_sync(snd, msg);
+ if (rc)
+ return rc;
+
+ /*
+ * The spec states that upon receipt of the RELEASE command "the device
+ * MUST complete all pending I/O messages for the specified stream ID".
+ * Thus, we consider the absence of I/O messages in the queue as an
+ * indication that the substream has been released.
+ */
+ rc = wait_event_interruptible_timeout(vss->msg_empty,
+ !virtsnd_pcm_msg_pending_num(vss),
+ js);
+ if (rc <= 0) {
+ dev_warn(&snd->vdev->dev, "SID %u: failed to flush I/O queue\n",
+ vss->sid);
+
+ return !rc ? -ETIMEDOUT : rc;
+ }
+
+ vss->release = false;
+
+ return 0;
+}
+
+/**
+ * virtsnd_pcm_pointer() - Get the current hardware position for the PCM
+ * substream.
+ * @substream: Kernel ALSA substream.
+ *
+ * Context: Any context. Takes and releases the VirtIO substream spinlock.
+ * Return: Hardware position in frames inside [0 ... buffer_size) range.
+ */
+static snd_pcm_uframes_t
+virtsnd_pcm_pointer(struct snd_pcm_substream *substream)
+{
+ struct virtio_pcm_substream *vss = snd_pcm_substream_chip(substream);
+ snd_pcm_uframes_t hw_ptr = SNDRV_PCM_POS_XRUN;
+ unsigned long flags;
+
+ spin_lock_irqsave(&vss->lock, flags);
+ if (!vss->xfer_xrun)
+ hw_ptr = bytes_to_frames(substream->runtime, vss->hw_ptr);
+ spin_unlock_irqrestore(&vss->lock, flags);
+
+ return hw_ptr;
+}
+
+/* PCM substream operators map. */
+const struct snd_pcm_ops virtsnd_pcm_ops = {
+ .open = virtsnd_pcm_open,
+ .close = virtsnd_pcm_close,
+ .ioctl = snd_pcm_lib_ioctl,
+ .hw_params = virtsnd_pcm_hw_params,
+ .hw_free = virtsnd_pcm_hw_free,
+ .prepare = virtsnd_pcm_prepare,
+ .trigger = virtsnd_pcm_trigger,
+ .sync_stop = virtsnd_pcm_sync_stop,
+ .pointer = virtsnd_pcm_pointer,
+};
--
2.30.1
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