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Subject: Re: [PATCH 5/7] ALSA: virtio: PCM substream operators
On 20.01.2021 09:36, Michael S. Tsirkin wrote:
CAUTION: This email originated from outside of the organization. Do not click links or open attachments unless you recognize the sender and know the content is safe. On Wed, Jan 20, 2021 at 01:36:33AM +0100, Anton Yakovlev wrote:Introduce the operators required for the operation of substreams. Signed-off-by: Anton Yakovlev <anton.yakovlev@opensynergy.com> --- sound/virtio/Makefile | 3 +- sound/virtio/virtio_pcm.c | 5 +- sound/virtio/virtio_pcm.h | 2 + sound/virtio/virtio_pcm_ops.c | 509 ++++++++++++++++++++++++++++++++++ 4 files changed, 517 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..8d26c1144ad6 --- /dev/null +++ b/sound/virtio/virtio_pcm_ops.c @@ -0,0 +1,509 @@ +// 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. + * + * The function waits for all pending I/O messages to complete. + * + * 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) +{ + return atomic_read(&substream->msg_count) == 0;All this use of atomic_read/atomic_set all over the place makes me pause. Could you add documentation explaining the use rules for these atomic fields?
I added some additional comments about that in v2: [5/9] virtio_pcm_msg.c:virtsnd_pcm_msg_complete() [6/9] virtio_pcm_ops.c:virtsnd_pcm_released()
+} + +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
-- Anton Yakovlev Senior Software Engineer OpenSynergy GmbH Rotherstr. 20, 10245 Berlin Phone: +49 30 60 98 54 0 E-Mail: anton.yakovlev@opensynergy.com www.opensynergy.com Handelsregister/Commercial Registry: Amtsgericht Charlottenburg, HRB 108616B GeschÃftsfÃhrer/Managing Director: Regis Adjamah
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