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310 lines
7.9 KiB
310 lines
7.9 KiB
// SPDX-License-Identifier: GPL-2.0+ |
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/* |
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* virtio-snd: Virtio sound device |
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* Copyright (C) 2021 OpenSynergy GmbH |
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*/ |
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#include <linux/moduleparam.h> |
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#include <linux/virtio_config.h> |
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#include "virtio_card.h" |
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/** |
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* struct virtio_snd_msg - Control message. |
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* @sg_request: Scattergather list containing a device request (header). |
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* @sg_response: Scattergather list containing a device response (status). |
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* @list: Pending message list entry. |
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* @notify: Request completed notification. |
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* @ref_count: Reference count used to manage a message lifetime. |
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*/ |
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struct virtio_snd_msg { |
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struct scatterlist sg_request; |
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struct scatterlist sg_response; |
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struct list_head list; |
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struct completion notify; |
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refcount_t ref_count; |
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}; |
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/** |
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* virtsnd_ctl_msg_ref() - Increment reference counter for the message. |
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* @msg: Control message. |
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* |
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* Context: Any context. |
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*/ |
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void virtsnd_ctl_msg_ref(struct virtio_snd_msg *msg) |
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{ |
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refcount_inc(&msg->ref_count); |
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} |
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/** |
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* virtsnd_ctl_msg_unref() - Decrement reference counter for the message. |
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* @msg: Control message. |
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* |
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* The message will be freed when the ref_count value is 0. |
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* |
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* Context: Any context. |
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*/ |
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void virtsnd_ctl_msg_unref(struct virtio_snd_msg *msg) |
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{ |
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if (refcount_dec_and_test(&msg->ref_count)) |
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kfree(msg); |
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} |
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/** |
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* virtsnd_ctl_msg_request() - Get a pointer to the request header. |
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* @msg: Control message. |
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* |
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* Context: Any context. |
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*/ |
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void *virtsnd_ctl_msg_request(struct virtio_snd_msg *msg) |
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{ |
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return sg_virt(&msg->sg_request); |
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} |
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/** |
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* virtsnd_ctl_msg_response() - Get a pointer to the response header. |
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* @msg: Control message. |
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* |
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* Context: Any context. |
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*/ |
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void *virtsnd_ctl_msg_response(struct virtio_snd_msg *msg) |
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{ |
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return sg_virt(&msg->sg_response); |
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} |
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/** |
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* virtsnd_ctl_msg_alloc() - Allocate and initialize a control message. |
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* @request_size: Size of request header. |
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* @response_size: Size of response header. |
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* @gfp: Kernel flags for memory allocation. |
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* |
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* The message will be automatically freed when the ref_count value is 0. |
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* |
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* Context: Any context. May sleep if @gfp flags permit. |
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* Return: Allocated message on success, NULL on failure. |
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*/ |
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struct virtio_snd_msg *virtsnd_ctl_msg_alloc(size_t request_size, |
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size_t response_size, gfp_t gfp) |
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{ |
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struct virtio_snd_msg *msg; |
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if (!request_size || !response_size) |
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return NULL; |
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msg = kzalloc(sizeof(*msg) + request_size + response_size, gfp); |
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if (!msg) |
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return NULL; |
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sg_init_one(&msg->sg_request, (u8 *)msg + sizeof(*msg), request_size); |
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sg_init_one(&msg->sg_response, (u8 *)msg + sizeof(*msg) + request_size, |
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response_size); |
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INIT_LIST_HEAD(&msg->list); |
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init_completion(&msg->notify); |
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/* This reference is dropped in virtsnd_ctl_msg_complete(). */ |
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refcount_set(&msg->ref_count, 1); |
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return msg; |
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} |
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/** |
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* virtsnd_ctl_msg_send() - Send a control message. |
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* @snd: VirtIO sound device. |
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* @msg: Control message. |
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* @out_sgs: Additional sg-list to attach to the request header (may be NULL). |
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* @in_sgs: Additional sg-list to attach to the response header (may be NULL). |
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* @nowait: Flag indicating whether to wait for completion. |
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* |
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* Context: Any context. Takes and releases the control queue spinlock. |
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* May sleep if @nowait is false. |
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* Return: 0 on success, -errno on failure. |
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*/ |
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int virtsnd_ctl_msg_send(struct virtio_snd *snd, struct virtio_snd_msg *msg, |
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struct scatterlist *out_sgs, |
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struct scatterlist *in_sgs, bool nowait) |
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{ |
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struct virtio_device *vdev = snd->vdev; |
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struct virtio_snd_queue *queue = virtsnd_control_queue(snd); |
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unsigned int js = msecs_to_jiffies(virtsnd_msg_timeout_ms); |
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struct virtio_snd_hdr *request = virtsnd_ctl_msg_request(msg); |
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struct virtio_snd_hdr *response = virtsnd_ctl_msg_response(msg); |
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unsigned int nouts = 0; |
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unsigned int nins = 0; |
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struct scatterlist *psgs[4]; |
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bool notify = false; |
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unsigned long flags; |
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int rc; |
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virtsnd_ctl_msg_ref(msg); |
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/* Set the default status in case the message was canceled. */ |
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response->code = cpu_to_le32(VIRTIO_SND_S_IO_ERR); |
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psgs[nouts++] = &msg->sg_request; |
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if (out_sgs) |
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psgs[nouts++] = out_sgs; |
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psgs[nouts + nins++] = &msg->sg_response; |
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if (in_sgs) |
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psgs[nouts + nins++] = in_sgs; |
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spin_lock_irqsave(&queue->lock, flags); |
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rc = virtqueue_add_sgs(queue->vqueue, psgs, nouts, nins, msg, |
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GFP_ATOMIC); |
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if (!rc) { |
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notify = virtqueue_kick_prepare(queue->vqueue); |
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list_add_tail(&msg->list, &snd->ctl_msgs); |
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} |
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spin_unlock_irqrestore(&queue->lock, flags); |
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if (rc) { |
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dev_err(&vdev->dev, "failed to send control message (0x%08x)\n", |
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le32_to_cpu(request->code)); |
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/* |
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* Since in this case virtsnd_ctl_msg_complete() will not be |
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* called, it is necessary to decrement the reference count. |
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*/ |
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virtsnd_ctl_msg_unref(msg); |
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goto on_exit; |
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} |
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if (notify) |
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virtqueue_notify(queue->vqueue); |
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if (nowait) |
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goto on_exit; |
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rc = wait_for_completion_interruptible_timeout(&msg->notify, js); |
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if (rc <= 0) { |
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if (!rc) { |
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dev_err(&vdev->dev, |
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"control message (0x%08x) timeout\n", |
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le32_to_cpu(request->code)); |
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rc = -ETIMEDOUT; |
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} |
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goto on_exit; |
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} |
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switch (le32_to_cpu(response->code)) { |
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case VIRTIO_SND_S_OK: |
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rc = 0; |
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break; |
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case VIRTIO_SND_S_NOT_SUPP: |
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rc = -EOPNOTSUPP; |
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break; |
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case VIRTIO_SND_S_IO_ERR: |
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rc = -EIO; |
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break; |
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default: |
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rc = -EINVAL; |
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break; |
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} |
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on_exit: |
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virtsnd_ctl_msg_unref(msg); |
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return rc; |
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} |
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/** |
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* virtsnd_ctl_msg_complete() - Complete a control message. |
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* @msg: Control message. |
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* |
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* Context: Any context. Expects the control queue spinlock to be held by |
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* caller. |
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*/ |
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void virtsnd_ctl_msg_complete(struct virtio_snd_msg *msg) |
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{ |
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list_del(&msg->list); |
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complete(&msg->notify); |
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virtsnd_ctl_msg_unref(msg); |
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} |
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/** |
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* virtsnd_ctl_msg_cancel_all() - Cancel all pending control messages. |
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* @snd: VirtIO sound device. |
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* |
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* Context: Any context. |
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*/ |
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void virtsnd_ctl_msg_cancel_all(struct virtio_snd *snd) |
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{ |
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struct virtio_snd_queue *queue = virtsnd_control_queue(snd); |
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unsigned long flags; |
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spin_lock_irqsave(&queue->lock, flags); |
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while (!list_empty(&snd->ctl_msgs)) { |
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struct virtio_snd_msg *msg = |
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list_first_entry(&snd->ctl_msgs, struct virtio_snd_msg, |
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list); |
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virtsnd_ctl_msg_complete(msg); |
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} |
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spin_unlock_irqrestore(&queue->lock, flags); |
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} |
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/** |
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* virtsnd_ctl_query_info() - Query the item configuration from the device. |
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* @snd: VirtIO sound device. |
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* @command: Control request code (VIRTIO_SND_R_XXX_INFO). |
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* @start_id: Item start identifier. |
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* @count: Item count to query. |
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* @size: Item information size in bytes. |
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* @info: Buffer for storing item information. |
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* |
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* Context: Any context that permits to sleep. |
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* Return: 0 on success, -errno on failure. |
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*/ |
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int virtsnd_ctl_query_info(struct virtio_snd *snd, int command, int start_id, |
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int count, size_t size, void *info) |
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{ |
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struct virtio_snd_msg *msg; |
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struct virtio_snd_query_info *query; |
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struct scatterlist sg; |
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msg = virtsnd_ctl_msg_alloc(sizeof(*query), |
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sizeof(struct virtio_snd_hdr), GFP_KERNEL); |
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if (!msg) |
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return -ENOMEM; |
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query = virtsnd_ctl_msg_request(msg); |
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query->hdr.code = cpu_to_le32(command); |
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query->start_id = cpu_to_le32(start_id); |
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query->count = cpu_to_le32(count); |
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query->size = cpu_to_le32(size); |
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sg_init_one(&sg, info, count * size); |
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return virtsnd_ctl_msg_send(snd, msg, NULL, &sg, false); |
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} |
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/** |
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* virtsnd_ctl_notify_cb() - Process all completed control messages. |
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* @vqueue: Underlying control virtqueue. |
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* |
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* This callback function is called upon a vring interrupt request from the |
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* device. |
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* |
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* Context: Interrupt context. Takes and releases the control queue spinlock. |
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*/ |
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void virtsnd_ctl_notify_cb(struct virtqueue *vqueue) |
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{ |
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struct virtio_snd *snd = vqueue->vdev->priv; |
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struct virtio_snd_queue *queue = virtsnd_control_queue(snd); |
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struct virtio_snd_msg *msg; |
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u32 length; |
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unsigned long flags; |
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spin_lock_irqsave(&queue->lock, flags); |
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do { |
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virtqueue_disable_cb(vqueue); |
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while ((msg = virtqueue_get_buf(vqueue, &length))) |
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virtsnd_ctl_msg_complete(msg); |
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if (unlikely(virtqueue_is_broken(vqueue))) |
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break; |
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} while (!virtqueue_enable_cb(vqueue)); |
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spin_unlock_irqrestore(&queue->lock, flags); |
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}
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