// 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_response() - 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(virtsnd_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_le32(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_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_le32(command);
query->start_id = cpu_to_le32(start_id);
query->count = cpu_to_le32(count);
query->size = cpu_to_le32(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);
} while (!virtqueue_enable_cb(vqueue));
spin_unlock_irqrestore(&queue->lock, flags);
}
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