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authorAnton Yakovlev <anton.yakovlev@opensynergy.com>2021-03-02 17:47:02 +0100
committerTakashi Iwai <tiwai@suse.de>2021-03-07 09:07:16 +0100
commitde3a9980d8c34b2479173e809afa820473db676a (patch)
tree8ae468b39ea7954e5e8aed0d2b62e20f094a2dc1 /sound/virtio
parent0ae0337f929a970ee8d83e0e95e6b8d05562ce3b (diff)
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ALSA: virtio: add virtio sound driver
Introduce skeleton of the virtio sound driver. The driver implements the virtio sound device specification, which has become part of the virtio standard. Initial initialization of the device, virtqueues and creation of an empty ALSA sound device. Signed-off-by: Anton Yakovlev <anton.yakovlev@opensynergy.com> Link: https://lore.kernel.org/r/20210302164709.3142702-3-anton.yakovlev@opensynergy.com Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound/virtio')
-rw-r--r--sound/virtio/Kconfig10
-rw-r--r--sound/virtio/Makefile7
-rw-r--r--sound/virtio/virtio_card.c324
-rw-r--r--sound/virtio/virtio_card.h65
4 files changed, 406 insertions, 0 deletions
diff --git a/sound/virtio/Kconfig b/sound/virtio/Kconfig
new file mode 100644
index 000000000000..094cba24ee5b
--- /dev/null
+++ b/sound/virtio/Kconfig
@@ -0,0 +1,10 @@
+# SPDX-License-Identifier: GPL-2.0+
+# Sound card driver for virtio
+
+config SND_VIRTIO
+ tristate "Virtio sound driver"
+ depends on VIRTIO
+ select SND_PCM
+ select SND_JACK
+ help
+ This is the virtual sound driver for virtio. Say Y or M.
diff --git a/sound/virtio/Makefile b/sound/virtio/Makefile
new file mode 100644
index 000000000000..8c87ebb9982b
--- /dev/null
+++ b/sound/virtio/Makefile
@@ -0,0 +1,7 @@
+# SPDX-License-Identifier: GPL-2.0+
+
+obj-$(CONFIG_SND_VIRTIO) += virtio_snd.o
+
+virtio_snd-objs := \
+ virtio_card.o
+
diff --git a/sound/virtio/virtio_card.c b/sound/virtio/virtio_card.c
new file mode 100644
index 000000000000..5a37056858e9
--- /dev/null
+++ b/sound/virtio/virtio_card.c
@@ -0,0 +1,324 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * virtio-snd: Virtio sound device
+ * Copyright (C) 2021 OpenSynergy GmbH
+ */
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/virtio_config.h>
+#include <sound/initval.h>
+#include <uapi/linux/virtio_ids.h>
+
+#include "virtio_card.h"
+
+static void virtsnd_remove(struct virtio_device *vdev);
+
+/**
+ * virtsnd_event_send() - Add an event to the event queue.
+ * @vqueue: Underlying event virtqueue.
+ * @event: Event.
+ * @notify: Indicates whether or not to send a notification to the device.
+ * @gfp: Kernel flags for memory allocation.
+ *
+ * Context: Any context.
+ */
+static void virtsnd_event_send(struct virtqueue *vqueue,
+ struct virtio_snd_event *event, bool notify,
+ gfp_t gfp)
+{
+ struct scatterlist sg;
+ struct scatterlist *psgs[1] = { &sg };
+
+ /* reset event content */
+ memset(event, 0, sizeof(*event));
+
+ sg_init_one(&sg, event, sizeof(*event));
+
+ if (virtqueue_add_sgs(vqueue, psgs, 0, 1, event, gfp) || !notify)
+ return;
+
+ if (virtqueue_kick_prepare(vqueue))
+ virtqueue_notify(vqueue);
+}
+
+/**
+ * virtsnd_event_dispatch() - Dispatch an event from the device side.
+ * @snd: VirtIO sound device.
+ * @event: VirtIO sound event.
+ *
+ * Context: Any context.
+ */
+static void virtsnd_event_dispatch(struct virtio_snd *snd,
+ struct virtio_snd_event *event)
+{
+}
+
+/**
+ * virtsnd_event_notify_cb() - Dispatch all reported events from the event queue.
+ * @vqueue: Underlying event virtqueue.
+ *
+ * This callback function is called upon a vring interrupt request from the
+ * device.
+ *
+ * Context: Interrupt context.
+ */
+static void virtsnd_event_notify_cb(struct virtqueue *vqueue)
+{
+ struct virtio_snd *snd = vqueue->vdev->priv;
+ struct virtio_snd_queue *queue = virtsnd_event_queue(snd);
+ struct virtio_snd_event *event;
+ u32 length;
+ unsigned long flags;
+
+ spin_lock_irqsave(&queue->lock, flags);
+ do {
+ virtqueue_disable_cb(vqueue);
+ while ((event = virtqueue_get_buf(vqueue, &length))) {
+ virtsnd_event_dispatch(snd, event);
+ virtsnd_event_send(vqueue, event, true, GFP_ATOMIC);
+ }
+ if (unlikely(virtqueue_is_broken(vqueue)))
+ break;
+ } while (!virtqueue_enable_cb(vqueue));
+ spin_unlock_irqrestore(&queue->lock, flags);
+}
+
+/**
+ * virtsnd_find_vqs() - Enumerate and initialize all virtqueues.
+ * @snd: VirtIO sound device.
+ *
+ * After calling this function, the event queue is disabled.
+ *
+ * Context: Any context.
+ * Return: 0 on success, -errno on failure.
+ */
+static int virtsnd_find_vqs(struct virtio_snd *snd)
+{
+ struct virtio_device *vdev = snd->vdev;
+ static vq_callback_t *callbacks[VIRTIO_SND_VQ_MAX] = {
+ [VIRTIO_SND_VQ_EVENT] = virtsnd_event_notify_cb
+ };
+ static const char *names[VIRTIO_SND_VQ_MAX] = {
+ [VIRTIO_SND_VQ_EVENT] = "virtsnd-event"
+ };
+ struct virtqueue *vqs[VIRTIO_SND_VQ_MAX] = { 0 };
+ unsigned int i;
+ unsigned int n;
+ int rc;
+
+ rc = virtio_find_vqs(vdev, VIRTIO_SND_VQ_MAX, vqs, callbacks, names,
+ NULL);
+ if (rc) {
+ dev_err(&vdev->dev, "failed to initialize virtqueues\n");
+ return rc;
+ }
+
+ for (i = 0; i < VIRTIO_SND_VQ_MAX; ++i)
+ snd->queues[i].vqueue = vqs[i];
+
+ /* Allocate events and populate the event queue */
+ virtqueue_disable_cb(vqs[VIRTIO_SND_VQ_EVENT]);
+
+ n = virtqueue_get_vring_size(vqs[VIRTIO_SND_VQ_EVENT]);
+
+ snd->event_msgs = kmalloc_array(n, sizeof(*snd->event_msgs),
+ GFP_KERNEL);
+ if (!snd->event_msgs)
+ return -ENOMEM;
+
+ for (i = 0; i < n; ++i)
+ virtsnd_event_send(vqs[VIRTIO_SND_VQ_EVENT],
+ &snd->event_msgs[i], false, GFP_KERNEL);
+
+ return 0;
+}
+
+/**
+ * virtsnd_enable_event_vq() - Enable the event virtqueue.
+ * @snd: VirtIO sound device.
+ *
+ * Context: Any context.
+ */
+static void virtsnd_enable_event_vq(struct virtio_snd *snd)
+{
+ struct virtio_snd_queue *queue = virtsnd_event_queue(snd);
+
+ if (!virtqueue_enable_cb(queue->vqueue))
+ virtsnd_event_notify_cb(queue->vqueue);
+}
+
+/**
+ * virtsnd_disable_event_vq() - Disable the event virtqueue.
+ * @snd: VirtIO sound device.
+ *
+ * Context: Any context.
+ */
+static void virtsnd_disable_event_vq(struct virtio_snd *snd)
+{
+ struct virtio_snd_queue *queue = virtsnd_event_queue(snd);
+ struct virtio_snd_event *event;
+ u32 length;
+ unsigned long flags;
+
+ if (queue->vqueue) {
+ spin_lock_irqsave(&queue->lock, flags);
+ virtqueue_disable_cb(queue->vqueue);
+ while ((event = virtqueue_get_buf(queue->vqueue, &length)))
+ virtsnd_event_dispatch(snd, event);
+ spin_unlock_irqrestore(&queue->lock, flags);
+ }
+}
+
+/**
+ * virtsnd_build_devs() - Read configuration and build ALSA devices.
+ * @snd: VirtIO sound device.
+ *
+ * Context: Any context that permits to sleep.
+ * Return: 0 on success, -errno on failure.
+ */
+static int virtsnd_build_devs(struct virtio_snd *snd)
+{
+ struct virtio_device *vdev = snd->vdev;
+ struct device *dev = &vdev->dev;
+ int rc;
+
+ rc = snd_card_new(dev, SNDRV_DEFAULT_IDX1, SNDRV_DEFAULT_STR1,
+ THIS_MODULE, 0, &snd->card);
+ if (rc < 0)
+ return rc;
+
+ snd->card->private_data = snd;
+
+ strscpy(snd->card->driver, VIRTIO_SND_CARD_DRIVER,
+ sizeof(snd->card->driver));
+ strscpy(snd->card->shortname, VIRTIO_SND_CARD_NAME,
+ sizeof(snd->card->shortname));
+ if (dev->parent->bus)
+ snprintf(snd->card->longname, sizeof(snd->card->longname),
+ VIRTIO_SND_CARD_NAME " at %s/%s/%s",
+ dev->parent->bus->name, dev_name(dev->parent),
+ dev_name(dev));
+ else
+ snprintf(snd->card->longname, sizeof(snd->card->longname),
+ VIRTIO_SND_CARD_NAME " at %s/%s",
+ dev_name(dev->parent), dev_name(dev));
+
+ return snd_card_register(snd->card);
+}
+
+/**
+ * virtsnd_validate() - Validate if the device can be started.
+ * @vdev: VirtIO parent device.
+ *
+ * Context: Any context.
+ * Return: 0 on success, -EINVAL on failure.
+ */
+static int virtsnd_validate(struct virtio_device *vdev)
+{
+ if (!vdev->config->get) {
+ dev_err(&vdev->dev, "configuration access disabled\n");
+ return -EINVAL;
+ }
+
+ if (!virtio_has_feature(vdev, VIRTIO_F_VERSION_1)) {
+ dev_err(&vdev->dev,
+ "device does not comply with spec version 1.x\n");
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+/**
+ * virtsnd_probe() - Create and initialize the device.
+ * @vdev: VirtIO parent device.
+ *
+ * Context: Any context that permits to sleep.
+ * Return: 0 on success, -errno on failure.
+ */
+static int virtsnd_probe(struct virtio_device *vdev)
+{
+ struct virtio_snd *snd;
+ unsigned int i;
+ int rc;
+
+ snd = devm_kzalloc(&vdev->dev, sizeof(*snd), GFP_KERNEL);
+ if (!snd)
+ return -ENOMEM;
+
+ snd->vdev = vdev;
+
+ vdev->priv = snd;
+
+ for (i = 0; i < VIRTIO_SND_VQ_MAX; ++i)
+ spin_lock_init(&snd->queues[i].lock);
+
+ rc = virtsnd_find_vqs(snd);
+ if (rc)
+ goto on_exit;
+
+ virtio_device_ready(vdev);
+
+ rc = virtsnd_build_devs(snd);
+ if (rc)
+ goto on_exit;
+
+ virtsnd_enable_event_vq(snd);
+
+on_exit:
+ if (rc)
+ virtsnd_remove(vdev);
+
+ return rc;
+}
+
+/**
+ * virtsnd_remove() - Remove VirtIO and ALSA devices.
+ * @vdev: VirtIO parent device.
+ *
+ * Context: Any context that permits to sleep.
+ */
+static void virtsnd_remove(struct virtio_device *vdev)
+{
+ struct virtio_snd *snd = vdev->priv;
+
+ virtsnd_disable_event_vq(snd);
+
+ if (snd->card)
+ snd_card_free(snd->card);
+
+ vdev->config->del_vqs(vdev);
+ vdev->config->reset(vdev);
+
+ kfree(snd->event_msgs);
+}
+
+static const struct virtio_device_id id_table[] = {
+ { VIRTIO_ID_SOUND, VIRTIO_DEV_ANY_ID },
+ { 0 },
+};
+
+static struct virtio_driver virtsnd_driver = {
+ .driver.name = KBUILD_MODNAME,
+ .driver.owner = THIS_MODULE,
+ .id_table = id_table,
+ .validate = virtsnd_validate,
+ .probe = virtsnd_probe,
+ .remove = virtsnd_remove,
+};
+
+static int __init init(void)
+{
+ return register_virtio_driver(&virtsnd_driver);
+}
+module_init(init);
+
+static void __exit fini(void)
+{
+ unregister_virtio_driver(&virtsnd_driver);
+}
+module_exit(fini);
+
+MODULE_DEVICE_TABLE(virtio, id_table);
+MODULE_DESCRIPTION("Virtio sound card driver");
+MODULE_LICENSE("GPL");
diff --git a/sound/virtio/virtio_card.h b/sound/virtio/virtio_card.h
new file mode 100644
index 000000000000..b903b1b12e90
--- /dev/null
+++ b/sound/virtio/virtio_card.h
@@ -0,0 +1,65 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * virtio-snd: Virtio sound device
+ * Copyright (C) 2021 OpenSynergy GmbH
+ */
+#ifndef VIRTIO_SND_CARD_H
+#define VIRTIO_SND_CARD_H
+
+#include <linux/slab.h>
+#include <linux/virtio.h>
+#include <sound/core.h>
+#include <uapi/linux/virtio_snd.h>
+
+#define VIRTIO_SND_CARD_DRIVER "virtio-snd"
+#define VIRTIO_SND_CARD_NAME "VirtIO SoundCard"
+
+/**
+ * struct virtio_snd_queue - Virtqueue wrapper structure.
+ * @lock: Used to synchronize access to a virtqueue.
+ * @vqueue: Underlying virtqueue.
+ */
+struct virtio_snd_queue {
+ spinlock_t lock;
+ struct virtqueue *vqueue;
+};
+
+/**
+ * struct virtio_snd - VirtIO sound card device.
+ * @vdev: Underlying virtio device.
+ * @queues: Virtqueue wrappers.
+ * @card: ALSA sound card.
+ * @event_msgs: Device events.
+ */
+struct virtio_snd {
+ struct virtio_device *vdev;
+ struct virtio_snd_queue queues[VIRTIO_SND_VQ_MAX];
+ struct snd_card *card;
+ struct virtio_snd_event *event_msgs;
+};
+
+static inline struct virtio_snd_queue *
+virtsnd_control_queue(struct virtio_snd *snd)
+{
+ return &snd->queues[VIRTIO_SND_VQ_CONTROL];
+}
+
+static inline struct virtio_snd_queue *
+virtsnd_event_queue(struct virtio_snd *snd)
+{
+ return &snd->queues[VIRTIO_SND_VQ_EVENT];
+}
+
+static inline struct virtio_snd_queue *
+virtsnd_tx_queue(struct virtio_snd *snd)
+{
+ return &snd->queues[VIRTIO_SND_VQ_TX];
+}
+
+static inline struct virtio_snd_queue *
+virtsnd_rx_queue(struct virtio_snd *snd)
+{
+ return &snd->queues[VIRTIO_SND_VQ_RX];
+}
+
+#endif /* VIRTIO_SND_CARD_H */