The control queue can be used by different parts of the driver to send commands to the device. Control messages can be either synchronous or asynchronous. The lifetime of a message is controlled by a reference count.
Introduce a module parameter to set the message completion timeout: msg_timeout_ms [=1000]
Signed-off-by: Anton Yakovlev anton.yakovlev@opensynergy.com --- sound/virtio/Makefile | 3 +- sound/virtio/virtio_card.c | 13 ++ sound/virtio/virtio_card.h | 7 + sound/virtio/virtio_ctl_msg.c | 311 ++++++++++++++++++++++++++++++++++ sound/virtio/virtio_ctl_msg.h | 78 +++++++++ 5 files changed, 411 insertions(+), 1 deletion(-) create mode 100644 sound/virtio/virtio_ctl_msg.c create mode 100644 sound/virtio/virtio_ctl_msg.h
diff --git a/sound/virtio/Makefile b/sound/virtio/Makefile index 8c87ebb9982b..dc551e637441 100644 --- a/sound/virtio/Makefile +++ b/sound/virtio/Makefile @@ -3,5 +3,6 @@ obj-$(CONFIG_SND_VIRTIO) += virtio_snd.o
virtio_snd-objs := \ - virtio_card.o + virtio_card.o \ + virtio_ctl_msg.o
diff --git a/sound/virtio/virtio_card.c b/sound/virtio/virtio_card.c index b5f63b5b7db4..c62b3a2da148 100644 --- a/sound/virtio/virtio_card.c +++ b/sound/virtio/virtio_card.c @@ -11,6 +11,10 @@
#include "virtio_card.h"
+int msg_timeout_ms = MSEC_PER_SEC; +module_param(msg_timeout_ms, int, 0644); +MODULE_PARM_DESC(msg_timeout_ms, "Message completion timeout in milliseconds"); + static void virtsnd_remove(struct virtio_device *vdev);
/** @@ -82,6 +86,7 @@ static int virtsnd_find_vqs(struct virtio_snd *snd) { struct virtio_device *vdev = snd->vdev; vq_callback_t *callbacks[VIRTIO_SND_VQ_MAX] = { + [VIRTIO_SND_VQ_CONTROL] = virtsnd_ctl_notify_cb, [VIRTIO_SND_VQ_EVENT] = virtsnd_event_notify_cb }; const char *names[VIRTIO_SND_VQ_MAX] = { @@ -218,6 +223,11 @@ static int virtsnd_validate(struct virtio_device *vdev) return -EINVAL; }
+ if (!msg_timeout_ms) { + dev_err(&vdev->dev, "msg_timeout_ms value cannot be zero\n"); + return -EINVAL; + } + return 0; }
@@ -240,6 +250,7 @@ static int virtsnd_probe(struct virtio_device *vdev)
snd->vdev = vdev; INIT_WORK(&snd->reset_work, virtsnd_reset_fn); + INIT_LIST_HEAD(&snd->ctl_msgs);
vdev->priv = snd;
@@ -278,6 +289,8 @@ static void virtsnd_remove(struct virtio_device *vdev) /* Stop all the virtqueues. */ vdev->config->reset(vdev);
+ virtsnd_ctl_msg_cancel_all(snd); + if (snd->card) snd_card_free(snd->card);
diff --git a/sound/virtio/virtio_card.h b/sound/virtio/virtio_card.h index 244381cc7a9b..c51a71a79388 100644 --- a/sound/virtio/virtio_card.h +++ b/sound/virtio/virtio_card.h @@ -11,6 +11,8 @@ #include <sound/core.h> #include <uapi/linux/virtio_snd.h>
+#include "virtio_ctl_msg.h" + #define VIRTIO_SND_CARD_DRIVER "virtio-snd" #define VIRTIO_SND_CARD_NAME "VirtIO SoundCard"
@@ -30,6 +32,7 @@ struct virtio_snd_queue { * @queues: Virtqueue wrappers. * @reset_work: Reset device work. * @card: ALSA sound card. + * @ctl_msgs: Pending control request list. * @event_msgs: Device events. */ struct virtio_snd { @@ -37,9 +40,13 @@ struct virtio_snd { struct virtio_snd_queue queues[VIRTIO_SND_VQ_MAX]; struct work_struct reset_work; struct snd_card *card; + struct list_head ctl_msgs; struct virtio_snd_event *event_msgs; };
+/* Message completion timeout in milliseconds (module parameter). */ +extern int msg_timeout_ms; + static inline struct virtio_snd_queue * virtsnd_control_queue(struct virtio_snd *snd) { diff --git a/sound/virtio/virtio_ctl_msg.c b/sound/virtio/virtio_ctl_msg.c new file mode 100644 index 000000000000..4b60b99c1d27 --- /dev/null +++ b/sound/virtio/virtio_ctl_msg.c @@ -0,0 +1,311 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * virtio-snd: Virtio sound device + * Copyright (C) 2021 OpenSynergy GmbH + */ +#include <linux/moduleparam.h> +#include <linux/virtio_config.h> + +#include "virtio_card.h" + +/** + * struct virtio_snd_msg - Control message. + * @sg_request: Scattergather list containing a device request (header). + * @sg_response: Scattergather list containing a device response (status). + * @list: Pending message list entry. + * @notify: Request completed notification. + * @ref_count: Reference count used to manage a message lifetime. + */ +struct virtio_snd_msg { + struct scatterlist sg_request; + struct scatterlist sg_response; + struct list_head list; + struct completion notify; + refcount_t ref_count; +}; + +/** + * virtsnd_ctl_msg_ref() - Increment reference counter for the message. + * @msg: Control message. + * + * Context: Any context. + */ +void virtsnd_ctl_msg_ref(struct virtio_snd_msg *msg) +{ + refcount_inc(&msg->ref_count); +} + +/** + * virtsnd_ctl_msg_unref() - Decrement reference counter for the message. + * @msg: Control message. + * + * The message will be freed when the ref_count value is 0. + * + * Context: Any context. + */ +void virtsnd_ctl_msg_unref(struct virtio_snd_msg *msg) +{ + if (refcount_dec_and_test(&msg->ref_count)) + kfree(msg); +} + +/** + * virtsnd_ctl_msg_request() - Get a pointer to the request header. + * @msg: Control message. + * + * Context: Any context. + */ +void *virtsnd_ctl_msg_request(struct virtio_snd_msg *msg) +{ + return sg_virt(&msg->sg_request); +} + +/** + * virtsnd_ctl_msg_request() - Get a pointer to the response header. + * @msg: Control message. + * + * Context: Any context. + */ +void *virtsnd_ctl_msg_response(struct virtio_snd_msg *msg) +{ + return sg_virt(&msg->sg_response); +} + +/** + * virtsnd_ctl_msg_alloc() - Allocate and initialize a control message. + * @request_size: Size of request header. + * @response_size: Size of response header. + * @gfp: Kernel flags for memory allocation. + * + * The message will be automatically freed when the ref_count value is 0. + * + * Context: Any context. May sleep if @gfp flags permit. + * Return: Allocated message on success, NULL on failure. + */ +struct virtio_snd_msg *virtsnd_ctl_msg_alloc(size_t request_size, + size_t response_size, gfp_t gfp) +{ + struct virtio_snd_msg *msg; + + if (!request_size || !response_size) + return NULL; + + msg = kzalloc(sizeof(*msg) + request_size + response_size, gfp); + if (!msg) + return NULL; + + sg_init_one(&msg->sg_request, (u8 *)msg + sizeof(*msg), request_size); + sg_init_one(&msg->sg_response, (u8 *)msg + sizeof(*msg) + request_size, + response_size); + + INIT_LIST_HEAD(&msg->list); + init_completion(&msg->notify); + /* This reference is dropped in virtsnd_ctl_msg_complete(). */ + refcount_set(&msg->ref_count, 1); + + return msg; +} + +/** + * virtsnd_ctl_msg_send() - Send a control message. + * @snd: VirtIO sound device. + * @msg: Control message. + * @out_sgs: Additional sg-list to attach to the request header (may be NULL). + * @in_sgs: Additional sg-list to attach to the response header (may be NULL). + * @nowait: Flag indicating whether to wait for completion. + * + * Context: Any context. Takes and releases the control queue spinlock. + * May sleep if @nowait is false. + * Return: 0 on success, -errno on failure. + */ +int virtsnd_ctl_msg_send(struct virtio_snd *snd, struct virtio_snd_msg *msg, + struct scatterlist *out_sgs, + struct scatterlist *in_sgs, bool nowait) +{ + struct virtio_device *vdev = snd->vdev; + struct virtio_snd_queue *queue = virtsnd_control_queue(snd); + unsigned int js = msecs_to_jiffies(msg_timeout_ms); + struct virtio_snd_hdr *request = virtsnd_ctl_msg_request(msg); + struct virtio_snd_hdr *response = virtsnd_ctl_msg_response(msg); + unsigned int nouts = 0; + unsigned int nins = 0; + struct scatterlist *psgs[4]; + bool notify = false; + unsigned long flags; + int rc; + + virtsnd_ctl_msg_ref(msg); + + /* Set the default status in case the message was canceled. */ + response->code = cpu_to_virtio32(vdev, VIRTIO_SND_S_IO_ERR); + + psgs[nouts++] = &msg->sg_request; + if (out_sgs) + psgs[nouts++] = out_sgs; + + psgs[nouts + nins++] = &msg->sg_response; + if (in_sgs) + psgs[nouts + nins++] = in_sgs; + + spin_lock_irqsave(&queue->lock, flags); + rc = virtqueue_add_sgs(queue->vqueue, psgs, nouts, nins, msg, + GFP_ATOMIC); + if (!rc) { + notify = virtqueue_kick_prepare(queue->vqueue); + + list_add_tail(&msg->list, &snd->ctl_msgs); + } + spin_unlock_irqrestore(&queue->lock, flags); + + if (rc) { + dev_err(&vdev->dev, "failed to send control message (0x%08x)\n", + le32_to_cpu(request->code)); + + /* + * Since in this case virtsnd_ctl_msg_complete() will not be + * called, it is necessary to decrement the reference count. + */ + virtsnd_ctl_msg_unref(msg); + + goto on_exit; + } + + if (notify) + virtqueue_notify(queue->vqueue); + + if (nowait) + goto on_exit; + + rc = wait_for_completion_interruptible_timeout(&msg->notify, js); + if (rc <= 0) { + if (!rc) { + dev_err(&vdev->dev, + "control message (0x%08x) timeout\n", + le32_to_cpu(request->code)); + rc = -ETIMEDOUT; + } + + goto on_exit; + } + + switch (le32_to_cpu(response->code)) { + case VIRTIO_SND_S_OK: + rc = 0; + break; + case VIRTIO_SND_S_NOT_SUPP: + rc = -EOPNOTSUPP; + break; + case VIRTIO_SND_S_IO_ERR: + rc = -EIO; + break; + default: + rc = -EINVAL; + break; + } + +on_exit: + virtsnd_ctl_msg_unref(msg); + + return rc; +} + +/** + * virtsnd_ctl_msg_complete() - Complete a control message. + * @msg: Control message. + * + * Context: Any context. Expects the control queue spinlock to be held by + * caller. + */ +void virtsnd_ctl_msg_complete(struct virtio_snd_msg *msg) +{ + list_del(&msg->list); + complete(&msg->notify); + + virtsnd_ctl_msg_unref(msg); +} + +/** + * virtsnd_ctl_msg_cancel_all() - Cancel all pending control messages. + * @snd: VirtIO sound device. + * + * Context: Any context. + */ +void virtsnd_ctl_msg_cancel_all(struct virtio_snd *snd) +{ + struct virtio_snd_queue *queue = virtsnd_control_queue(snd); + unsigned long flags; + + spin_lock_irqsave(&queue->lock, flags); + while (!list_empty(&snd->ctl_msgs)) { + struct virtio_snd_msg *msg = + list_first_entry(&snd->ctl_msgs, struct virtio_snd_msg, + list); + + virtsnd_ctl_msg_complete(msg); + } + spin_unlock_irqrestore(&queue->lock, flags); +} + +/** + * virtsnd_ctl_query_info() - Query the item configuration from the device. + * @snd: VirtIO sound device. + * @command: Control request code (VIRTIO_SND_R_XXX_INFO). + * @start_id: Item start identifier. + * @count: Item count to query. + * @size: Item information size in bytes. + * @info: Buffer for storing item information. + * + * Context: Any context that permits to sleep. + * Return: 0 on success, -errno on failure. + */ +int virtsnd_ctl_query_info(struct virtio_snd *snd, int command, int start_id, + int count, size_t size, void *info) +{ + struct virtio_device *vdev = snd->vdev; + struct virtio_snd_msg *msg; + struct virtio_snd_query_info *query; + struct scatterlist sg; + + msg = virtsnd_ctl_msg_alloc(sizeof(*query), + sizeof(struct virtio_snd_hdr), GFP_KERNEL); + if (!msg) + return -ENOMEM; + + query = virtsnd_ctl_msg_request(msg); + query->hdr.code = cpu_to_virtio32(vdev, command); + query->start_id = cpu_to_virtio32(vdev, start_id); + query->count = cpu_to_virtio32(vdev, count); + query->size = cpu_to_virtio32(vdev, size); + + sg_init_one(&sg, info, count * size); + + return virtsnd_ctl_msg_send(snd, msg, NULL, &sg, false); +} + +/** + * virtsnd_ctl_notify_cb() - Process all completed control messages. + * @vqueue: Underlying control virtqueue. + * + * This callback function is called upon a vring interrupt request from the + * device. + * + * Context: Interrupt context. Takes and releases the control queue spinlock. + */ +void virtsnd_ctl_notify_cb(struct virtqueue *vqueue) +{ + struct virtio_snd *snd = vqueue->vdev->priv; + struct virtio_snd_queue *queue = virtsnd_control_queue(snd); + struct virtio_snd_msg *msg; + u32 length; + unsigned long flags; + + spin_lock_irqsave(&queue->lock, flags); + do { + virtqueue_disable_cb(vqueue); + while ((msg = virtqueue_get_buf(vqueue, &length))) + virtsnd_ctl_msg_complete(msg); + if (unlikely(virtqueue_is_broken(vqueue))) + break; + } while (!virtqueue_enable_cb(vqueue)); + spin_unlock_irqrestore(&queue->lock, flags); +} diff --git a/sound/virtio/virtio_ctl_msg.h b/sound/virtio/virtio_ctl_msg.h new file mode 100644 index 000000000000..7f4db044f28e --- /dev/null +++ b/sound/virtio/virtio_ctl_msg.h @@ -0,0 +1,78 @@ +/* SPDX-License-Identifier: GPL-2.0+ */ +/* + * virtio-snd: Virtio sound device + * Copyright (C) 2021 OpenSynergy GmbH + */ +#ifndef VIRTIO_SND_MSG_H +#define VIRTIO_SND_MSG_H + +#include <linux/atomic.h> +#include <linux/virtio.h> + +struct virtio_snd; +struct virtio_snd_msg; + +void virtsnd_ctl_msg_ref(struct virtio_snd_msg *msg); + +void virtsnd_ctl_msg_unref(struct virtio_snd_msg *msg); + +void *virtsnd_ctl_msg_request(struct virtio_snd_msg *msg); + +void *virtsnd_ctl_msg_response(struct virtio_snd_msg *msg); + +struct virtio_snd_msg *virtsnd_ctl_msg_alloc(size_t request_size, + size_t response_size, gfp_t gfp); + +int virtsnd_ctl_msg_send(struct virtio_snd *snd, struct virtio_snd_msg *msg, + struct scatterlist *out_sgs, + struct scatterlist *in_sgs, bool nowait); + +/** + * virtsnd_ctl_msg_send_sync() - Simplified sending of synchronous message. + * @snd: VirtIO sound device. + * @msg: Control message. + * + * After returning from this function, the message will be deleted. If message + * content is still needed, the caller must additionally to + * virtsnd_ctl_msg_ref/unref() it. + * + * The msg_timeout_ms module parameter defines the message completion timeout. + * If the message is not completed within this time, the function will return an + * error. + * + * Context: Any context that permits to sleep. + * Return: 0 on success, -errno on failure. + * + * The return value is a message status code (VIRTIO_SND_S_XXX) converted to an + * appropriate -errno value. + */ +static inline int virtsnd_ctl_msg_send_sync(struct virtio_snd *snd, + struct virtio_snd_msg *msg) +{ + return virtsnd_ctl_msg_send(snd, msg, NULL, NULL, false); +} + +/** + * virtsnd_ctl_msg_send_async() - Simplified sending of asynchronous message. + * @snd: VirtIO sound device. + * @msg: Control message. + * + * Context: Any context. + * Return: 0 on success, -errno on failure. + */ +static inline int virtsnd_ctl_msg_send_async(struct virtio_snd *snd, + struct virtio_snd_msg *msg) +{ + return virtsnd_ctl_msg_send(snd, msg, NULL, NULL, true); +} + +void virtsnd_ctl_msg_cancel_all(struct virtio_snd *snd); + +void virtsnd_ctl_msg_complete(struct virtio_snd_msg *msg); + +int virtsnd_ctl_query_info(struct virtio_snd *snd, int command, int start_id, + int count, size_t size, void *info); + +void virtsnd_ctl_notify_cb(struct virtqueue *vqueue); + +#endif /* VIRTIO_SND_MSG_H */