[PATCH v2 6/9] ALSA: virtio: PCM substream operators
Anton Yakovlev
anton.yakovlev at opensynergy.com
Sun Jan 24 17:54:05 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 | 5 +-
sound/virtio/virtio_pcm.h | 2 +
sound/virtio/virtio_pcm_ops.c | 513 ++++++++++++++++++++++++++++++++++
4 files changed, 521 insertions(+), 2 deletions(-)
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 1ab50dcc88c8..6a1ca6b2c3ca 100644
--- a/sound/virtio/virtio_pcm.c
+++ b/sound/virtio/virtio_pcm.c
@@ -121,7 +121,8 @@ static int virtsnd_pcm_build_hw(struct virtio_pcm_substream *substream,
SNDRV_PCM_INFO_MMAP_VALID |
SNDRV_PCM_INFO_BATCH |
SNDRV_PCM_INFO_BLOCK_TRANSFER |
- SNDRV_PCM_INFO_INTERLEAVED;
+ SNDRV_PCM_INFO_INTERLEAVED |
+ SNDRV_PCM_INFO_PAUSE;
if (!info->channels_min || info->channels_min > info->channels_max) {
dev_err(&vdev->dev,
@@ -503,6 +504,8 @@ int virtsnd_pcm_build_devs(struct virtio_snd *snd)
if (rc)
return rc;
}
+
+ snd_pcm_set_ops(pcm->pcm, i, &virtsnd_pcm_ops);
}
return 0;
diff --git a/sound/virtio/virtio_pcm.h b/sound/virtio/virtio_pcm.h
index d011b7e1d18d..fe467bc05d8b 100644
--- a/sound/virtio/virtio_pcm.h
+++ b/sound/virtio/virtio_pcm.h
@@ -90,6 +90,8 @@ 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..19882777fcd6
--- /dev/null
+++ b/sound/virtio/virtio_pcm_ops.c
@@ -0,0 +1,513 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Sound card driver for virtio
+ * Copyright (C) 2020 OpenSynergy GmbH
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+#include <sound/pcm_params.h>
+
+#include "virtio_card.h"
+
+/*
+ * Our main concern here is maintaining the correct state of the underlying I/O
+ * virtqueues. Thus, operators are implemented to support all of the following
+ * possible control paths (excluding all trivial ones):
+ *
+ * +---------+
+ * | open() |<------------------+
+ * +----+----+ |
+ * v |
+ * +------+------+ |
+ * +------------->| hw_params() |<-------------+ |
+ * | +-------------+ | |
+ * | v | |
+ * | +-----------+ | |
+ * | | prepare() |<-----------+ | |
+ * | +-----------+ | | |
+ * | v | | |
+ * | +-------------------------+ | | |
+ * +-----------+ | trigger(START/ | | | |
+ * | restore() | | PAUSE_RELEASE/ |<-+ | | |
+ * +-----------+ | RESUME) | | | | |
+ * ^ +-------------------------+ | | | |
+ * | v | | | |
+ * | +-----------+ | | | |
+ * | | pointer() | | | | |
+ * | +-----------+ | | | |
+ * | v | | | |
+ * | +---------------------+ | | | |
+ * +-----------+ | trigger(STOP/ |----+ | | |
+ * | freeze() |<---| PAUSE_PUSH/ |-------+ | |
+ * +-----------+ | SUSPEND) | | |
+ * +---------------------+ | |
+ * v | |
+ * +-----------+ | |
+ * | hw_free() |---------------+ |
+ * +-----------+ |
+ * v |
+ * +---------+ |
+ * | close() |-------------------+
+ * +---------+
+ */
+
+/* Map for converting ALSA format to VirtIO format. */
+struct virtsnd_a2v_format {
+ unsigned int 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 }
+};
+
+/**
+ * virtsnd_pcm_release() - Release the PCM substream on the device side.
+ * @substream: VirtIO substream.
+ *
+ * Context: Any context that permits to sleep.
+ * Return: 0 on success, -errno on failure.
+ */
+static inline bool virtsnd_pcm_released(struct virtio_pcm_substream *substream)
+{
+ /*
+ * 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.
+ */
+ return atomic_read(&substream->msg_count) == 0;
+}
+
+static int virtsnd_pcm_release(struct virtio_pcm_substream *substream)
+{
+ struct virtio_snd *snd = substream->snd;
+ struct virtio_snd_msg *msg;
+ unsigned int js = msecs_to_jiffies(msg_timeout_ms);
+ int rc;
+
+ msg = virtsnd_pcm_ctl_msg_alloc(substream, VIRTIO_SND_R_PCM_RELEASE,
+ GFP_KERNEL);
+ if (IS_ERR(msg))
+ return PTR_ERR(msg);
+
+ rc = virtsnd_ctl_msg_send_sync(snd, msg);
+ if (rc)
+ return rc;
+
+ return wait_event_interruptible_timeout(substream->msg_empty,
+ virtsnd_pcm_released(substream),
+ js);
+}
+
+/**
+ * virtsnd_pcm_open() - Open the PCM substream.
+ * @substream: Kernel ALSA substream.
+ *
+ * Context: Any context.
+ * Return: 0 on success, -errno on failure.
+ */
+static int virtsnd_pcm_open(struct snd_pcm_substream *substream)
+{
+ struct virtio_pcm *pcm = snd_pcm_substream_chip(substream);
+ struct virtio_pcm_substream *ss = NULL;
+
+ if (pcm) {
+ switch (substream->stream) {
+ case SNDRV_PCM_STREAM_PLAYBACK:
+ case SNDRV_PCM_STREAM_CAPTURE: {
+ struct virtio_pcm_stream *stream =
+ &pcm->streams[substream->stream];
+
+ if (substream->number < stream->nsubstreams)
+ ss = stream->substreams[substream->number];
+ break;
+ }
+ }
+ }
+
+ if (!ss)
+ return -EBADFD;
+
+ substream->runtime->hw = ss->hw;
+ substream->private_data = ss;
+
+ return 0;
+}
+
+/**
+ * virtsnd_pcm_close() - Close the PCM substream.
+ * @substream: Kernel ALSA substream.
+ *
+ * Context: Any 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).
+ *
+ * In all cases, the function:
+ * 1. checks the state of the virtqueue and, if necessary, tries to fix it,
+ * 2. sets the parameters on the device side,
+ * 3. allocates a hardware buffer and I/O messages.
+ *
+ * Context: Any context that permits to sleep.
+ * 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 *ss = snd_pcm_substream_chip(substream);
+ struct virtio_device *vdev = ss->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 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;
+ }
+ }
+
+ /* 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(ss, VIRTIO_SND_R_PCM_SET_PARAMS,
+ GFP_KERNEL);
+ if (IS_ERR(msg))
+ return PTR_ERR(msg);
+
+ request = sg_virt(&msg->sg_request);
+
+ request->buffer_bytes = cpu_to_virtio32(vdev, buffer_bytes);
+ request->period_bytes = cpu_to_virtio32(vdev, period_bytes);
+ request->channels = channels;
+ request->format = vformat;
+ request->rate = vrate;
+
+ if (ss->features & (1U << VIRTIO_SND_PCM_F_MSG_POLLING))
+ request->features |=
+ cpu_to_virtio32(vdev,
+ 1U << VIRTIO_SND_PCM_F_MSG_POLLING);
+
+ if (ss->features & (1U << VIRTIO_SND_PCM_F_EVT_XRUNS))
+ request->features |=
+ cpu_to_virtio32(vdev,
+ 1U << VIRTIO_SND_PCM_F_EVT_XRUNS);
+
+ rc = virtsnd_ctl_msg_send_sync(ss->snd, msg);
+ if (rc)
+ return rc;
+
+ /* If the buffer was already allocated earlier, do nothing. */
+ if (runtime->dma_area)
+ return 0;
+
+ /* Allocate hardware buffer */
+ rc = snd_pcm_lib_malloc_pages(substream, buffer_bytes);
+ if (rc < 0)
+ return rc;
+
+ /* Allocate and initialize I/O messages */
+ rc = virtsnd_pcm_msg_alloc(ss, periods, runtime->dma_area,
+ period_bytes);
+ if (rc)
+ snd_pcm_lib_free_pages(substream);
+
+ return rc;
+}
+
+/**
+ * virtsnd_pcm_hw_free() - Reset the parameters of the PCM substream.
+ * @substream: Kernel ALSA substream.
+ *
+ * The function does the following:
+ * 1. tries to release the PCM substream on the device side,
+ * 2. frees the hardware buffer.
+ *
+ * Context: Any context that permits to sleep.
+ * Return: 0 on success, -errno on failure.
+ */
+static int virtsnd_pcm_hw_free(struct snd_pcm_substream *substream)
+{
+ struct virtio_pcm_substream *ss = snd_pcm_substream_chip(substream);
+ int rc;
+
+ rc = virtsnd_pcm_release(ss);
+
+ /*
+ * Even if we failed to send the RELEASE message or wait for the queue
+ * flush to complete, we can safely delete the buffer. Because after
+ * receiving the STOP command, the device must stop all I/O message
+ * processing. If there are still pending messages in the queue, the
+ * next ops->hw_params() call should deal with this.
+ */
+ snd_pcm_lib_free_pages(substream);
+
+ return rc;
+}
+
+/**
+ * virtsnd_pcm_hw_params() - Prepare the PCM substream.
+ * @substream: Kernel ALSA substream.
+ *
+ * The function can be called both from the upper level or from the driver
+ * itself.
+ *
+ * In all cases, the function:
+ * 1. checks the state of the virtqueue and, if necessary, tries to fix it,
+ * 2. prepares the substream on the device side.
+ *
+ * Context: Any context that permits to sleep. May take and release the tx/rx
+ * queue spinlock.
+ * Return: 0 on success, -errno on failure.
+ */
+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);
+
+ /*
+ * 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->xfer_xrun, 0);
+ atomic_set(&ss->msg_count, 0);
+
+ msg = virtsnd_pcm_ctl_msg_alloc(ss, VIRTIO_SND_R_PCM_PREPARE,
+ GFP_KERNEL);
+ if (IS_ERR(msg))
+ return PTR_ERR(msg);
+
+ return virtsnd_ctl_msg_send_sync(ss->snd, msg);
+}
+
+/**
+ * virtsnd_pcm_trigger() - Process command for the PCM substream.
+ * @substream: Kernel ALSA substream.
+ * @command: Substream command (SNDRV_PCM_TRIGGER_XXX).
+ *
+ * Depending on the command, the function does the following:
+ * 1. enables/disables data transmission,
+ * 2. starts/stops the substream on the device side.
+ *
+ * Context: Atomic context. 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 *ss = snd_pcm_substream_chip(substream);
+ struct virtio_snd *snd = ss->snd;
+ struct virtio_snd_queue *queue = virtsnd_pcm_queue(ss);
+ struct virtio_snd_msg *msg;
+
+ switch (command) {
+ case SNDRV_PCM_TRIGGER_START:
+ case SNDRV_PCM_TRIGGER_PAUSE_RELEASE: {
+ int rc;
+
+ spin_lock(&queue->lock);
+ rc = virtsnd_pcm_msg_send(ss);
+ spin_unlock(&queue->lock);
+ if (rc)
+ return rc;
+
+ atomic_set(&ss->xfer_enabled, 1);
+
+ msg = virtsnd_pcm_ctl_msg_alloc(ss, VIRTIO_SND_R_PCM_START,
+ GFP_ATOMIC);
+ if (IS_ERR(msg))
+ return PTR_ERR(msg);
+
+ return virtsnd_ctl_msg_send(snd, msg);
+ }
+ case SNDRV_PCM_TRIGGER_STOP:
+ case SNDRV_PCM_TRIGGER_PAUSE_PUSH: {
+ atomic_set(&ss->xfer_enabled, 0);
+
+ msg = virtsnd_pcm_ctl_msg_alloc(ss, VIRTIO_SND_R_PCM_STOP,
+ GFP_ATOMIC);
+ if (IS_ERR(msg))
+ return PTR_ERR(msg);
+
+ return virtsnd_ctl_msg_send(snd, msg);
+ }
+ default: {
+ return -EINVAL;
+ }
+ }
+}
+
+/**
+ * virtsnd_pcm_pointer() - Get the current hardware position for the PCM
+ * substream.
+ * @substream: Kernel ALSA substream.
+ *
+ * Context: Atomic context.
+ * 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 *ss = snd_pcm_substream_chip(substream);
+
+ if (atomic_read(&ss->xfer_xrun))
+ return SNDRV_PCM_POS_XRUN;
+
+ return (snd_pcm_uframes_t)atomic_read(&ss->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,
+ .pointer = virtsnd_pcm_pointer,
+};
--
2.30.0
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