From patchwork Mon Feb 22 15:34:41 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Anton Yakovlev X-Patchwork-Id: 12098955 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3E0B3C433DB for ; Mon, 22 Feb 2021 15:39:43 +0000 (UTC) Received: from alsa0.perex.cz (alsa0.perex.cz [77.48.224.243]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 82BCD64E74 for ; Mon, 22 Feb 2021 15:39:42 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 82BCD64E74 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=opensynergy.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=alsa-devel-bounces@alsa-project.org Received: from alsa1.perex.cz (alsa1.perex.cz [207.180.221.201]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by alsa0.perex.cz (Postfix) with ESMTPS id E6F55167D; Mon, 22 Feb 2021 16:38:50 +0100 (CET) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa0.perex.cz E6F55167D DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=alsa-project.org; s=default; t=1614008381; bh=CTrCnQzFwTAEvjLTf9Iv25SL8u5YH+eIX/0REMyx9YE=; h=From:To:Subject:Date:In-Reply-To:References:Cc:List-Id: List-Unsubscribe:List-Archive:List-Post:List-Help:List-Subscribe: From; b=myvK5anD9sxbfGoYt95B91dCCzVO4+PChuzM4UVCS5WSNQuPnIgTE2rFMjeBm4oB0 eppPazjr1cZQ23JzjrjRXGHF9Y0R8b7+v4R3qddJFwsctn3y7ASawE6fWRFBz76B0R 15CE0rz94VkAYV6Nhy1ERKVInSRS4rYPAdVPLTws= Received: from alsa1.perex.cz (localhost.localdomain [127.0.0.1]) by alsa1.perex.cz (Postfix) with ESMTP id 7DB5CF804B0; Mon, 22 Feb 2021 16:36:18 +0100 (CET) Received: by alsa1.perex.cz (Postfix, from userid 50401) id CEB84F804AA; Mon, 22 Feb 2021 16:36:14 +0100 (CET) Received: from mx1.opensynergy.com (mx1.opensynergy.com [217.66.60.4]) (using TLSv1.2 with cipher ADH-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by alsa1.perex.cz (Postfix) with ESMTPS id 845AAF8025E for ; Mon, 22 Feb 2021 16:36:10 +0100 (CET) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa1.perex.cz 845AAF8025E Authentication-Results: alsa1.perex.cz; dkim=pass (2048-bit key) header.d=opensynergy.com header.i=@opensynergy.com header.b="q5J7Ux00" Received: from SR-MAILGATE-02.opensynergy.com (localhost.localdomain [127.0.0.1]) by mx1.opensynergy.com (Proxmox) with ESMTP id 2181CA13EC; Mon, 22 Feb 2021 16:36:10 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=opensynergy.com; h=cc:cc:content-transfer-encoding:content-type:content-type :date:from:from:in-reply-to:message-id:mime-version:references :reply-to:subject:subject:to:to; s=srmailgate02; bh=dDMP9wB02BpD ZmEaig0fD+4KahtJhHECHR1hu1zLULo=; b=q5J7Ux00F/WmlehpN08/U54brxmH cnNv+3lPDXMG3dllNU4Dd5kVC69JMUQvpChiil9hq+SqKZb3dt5L7+1P+rM4NWqb sPXEgFBXIJmW5PTZb5jem4OATJGYyMoTcVsW5jYQW8uzLgq9wAh4thxxWiGXV3en 2fGBlmf1VXocvWwE42U7wDoMqcnJQaC3f8Uh41/JCVZ3/nKG/6SSKPiqsnQ4ITR3 LSDdjZN2ZGxEGkPlW+I2cBxTjkEnS6bHkhvw6ofneqSlHrJvNGmPNVNNXXsEHnmJ j60wrfsBbUlh2LWT3OkTWCnisyQIODvXBRteyXz8N0YUsq4Xl64WTYV38g== From: Anton Yakovlev To: , , Subject: [PATCH v5 6/9] ALSA: virtio: PCM substream operators Date: Mon, 22 Feb 2021 16:34:41 +0100 Message-ID: <20210222153444.348390-7-anton.yakovlev@opensynergy.com> X-Mailer: git-send-email 2.30.0 In-Reply-To: <20210222153444.348390-1-anton.yakovlev@opensynergy.com> References: <20210222153444.348390-1-anton.yakovlev@opensynergy.com> MIME-Version: 1.0 X-ClientProxiedBy: SR-MAIL-01.open-synergy.com (10.26.10.21) To SR-MAIL-02.open-synergy.com (10.26.10.22) Cc: linux-kernel@vger.kernel.org, Takashi Iwai , "Michael S. Tsirkin" X-BeenThere: alsa-devel@alsa-project.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: "Alsa-devel mailing list for ALSA developers - http://www.alsa-project.org" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: alsa-devel-bounces@alsa-project.org Sender: "Alsa-devel" Introduce the operators required for the operation of substreams. Signed-off-by: Anton Yakovlev --- sound/virtio/Makefile | 3 +- sound/virtio/virtio_pcm.c | 2 + sound/virtio/virtio_pcm.h | 4 + sound/virtio/virtio_pcm_ops.c | 469 ++++++++++++++++++++++++++++++++++ 4 files changed, 477 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 c70e4fed9044..c48d00acee2e 100644 --- a/sound/virtio/virtio_pcm.h +++ b/sound/virtio/virtio_pcm.h @@ -35,6 +35,7 @@ struct virtio_pcm_msg; * @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. * @msg_empty: Notify when msg_count is zero. + * @msg_flushing: True if the I/O queue is in flushing state. */ struct virtio_pcm_substream { struct virtio_snd *snd; @@ -56,6 +57,7 @@ struct virtio_pcm_substream { int msg_last_enqueued; unsigned int msg_count; wait_queue_head_t msg_empty; + bool msg_flushing; }; /** @@ -82,6 +84,8 @@ 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..07510778b555 --- /dev/null +++ b/sound/virtio/virtio_pcm_ops.c @@ -0,0 +1,469 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * virtio-snd: Virtio sound device + * Copyright (C) 2021 OpenSynergy GmbH + */ +#include + +#include "virtio_card.h" + +/* 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_substream *vss = NULL; + + if (vpcm) { + switch (substream->stream) { + case SNDRV_PCM_STREAM_PLAYBACK: + case SNDRV_PCM_STREAM_CAPTURE: { + struct virtio_pcm_stream *vs = + &vpcm->streams[substream->stream]; + + if (substream->number < vs->nsubstreams) + vss = vs->substreams[substream->number]; + break; + } + } + } + + if (!vss) + return -EBADFD; + + 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->msg_flushing = true; + + 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 (vss->msg_flushing) { + 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; + + 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) +{ + 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. Takes and releases the VirtIO substream spinlock. + * Return: 0 on success, -errno on failure. + */ +static int virtsnd_pcm_prepare(struct snd_pcm_substream *substream) +{ + 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; + unsigned long flags; + + if (vss->msg_flushing) { + dev_err(&vdev->dev, "SID %u: invalid I/O queue state\n", + vss->sid); + return -EBADFD; + } + + spin_lock_irqsave(&vss->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. + */ + vss->frame_bytes = runtime->frame_bits >> 3; + vss->period_size = runtime->period_size; + vss->buffer_size = runtime->buffer_size; + + vss->hw_ptr = 0; + vss->xfer_xrun = false; + vss->msg_last_enqueued = -1; + vss->msg_count = 0; + spin_unlock_irqrestore(&vss->lock, flags); + + 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 I/O queue needs to be flushed only when the substream is + * completely stopped. + */ + if (command == SNDRV_PCM_TRIGGER_STOP) + vss->msg_flushing = true; + + /* + * 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_msg_count() - Returns the number of pending I/O messages. + * @vss: VirtIO substream. + * + * Context: Any context. + * Return: Number of messages. + */ +static inline +unsigned int virtsnd_pcm_msg_count(struct virtio_pcm_substream *vss) +{ + unsigned int msg_count; + unsigned long flags; + + spin_lock_irqsave(&vss->lock, flags); + msg_count = vss->msg_count; + spin_unlock_irqrestore(&vss->lock, flags); + + return msg_count; +} + +/** + * 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->msg_flushing) + return 0; + + if (!virtsnd_pcm_msg_count(vss)) + goto on_exit; + + 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_count(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; + } + +on_exit: + vss->msg_flushing = 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 = 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, +};