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1// SPDX-License-Identifier: GPL-2.0+2/*3 * virtio-snd: Virtio sound device4 * Copyright (C) 2021 OpenSynergy GmbH5 */6#include <linux/moduleparam.h>7#include <linux/virtio_config.h>8 9#include "virtio_card.h"10 11/**12 * struct virtio_snd_msg - Control message.13 * @sg_request: Scattergather list containing a device request (header).14 * @sg_response: Scattergather list containing a device response (status).15 * @list: Pending message list entry.16 * @notify: Request completed notification.17 * @ref_count: Reference count used to manage a message lifetime.18 */19struct virtio_snd_msg {20 struct scatterlist sg_request;21 struct scatterlist sg_response;22 struct list_head list;23 struct completion notify;24 refcount_t ref_count;25};26 27/**28 * virtsnd_ctl_msg_ref() - Increment reference counter for the message.29 * @msg: Control message.30 *31 * Context: Any context.32 */33void virtsnd_ctl_msg_ref(struct virtio_snd_msg *msg)34{35 refcount_inc(&msg->ref_count);36}37 38/**39 * virtsnd_ctl_msg_unref() - Decrement reference counter for the message.40 * @msg: Control message.41 *42 * The message will be freed when the ref_count value is 0.43 *44 * Context: Any context.45 */46void virtsnd_ctl_msg_unref(struct virtio_snd_msg *msg)47{48 if (refcount_dec_and_test(&msg->ref_count))49 kfree(msg);50}51 52/**53 * virtsnd_ctl_msg_request() - Get a pointer to the request header.54 * @msg: Control message.55 *56 * Context: Any context.57 */58void *virtsnd_ctl_msg_request(struct virtio_snd_msg *msg)59{60 return sg_virt(&msg->sg_request);61}62 63/**64 * virtsnd_ctl_msg_response() - Get a pointer to the response header.65 * @msg: Control message.66 *67 * Context: Any context.68 */69void *virtsnd_ctl_msg_response(struct virtio_snd_msg *msg)70{71 return sg_virt(&msg->sg_response);72}73 74/**75 * virtsnd_ctl_msg_alloc() - Allocate and initialize a control message.76 * @request_size: Size of request header.77 * @response_size: Size of response header.78 * @gfp: Kernel flags for memory allocation.79 *80 * The message will be automatically freed when the ref_count value is 0.81 *82 * Context: Any context. May sleep if @gfp flags permit.83 * Return: Allocated message on success, NULL on failure.84 */85struct virtio_snd_msg *virtsnd_ctl_msg_alloc(size_t request_size,86 size_t response_size, gfp_t gfp)87{88 struct virtio_snd_msg *msg;89 90 if (!request_size || !response_size)91 return NULL;92 93 msg = kzalloc(sizeof(*msg) + request_size + response_size, gfp);94 if (!msg)95 return NULL;96 97 sg_init_one(&msg->sg_request, (u8 *)msg + sizeof(*msg), request_size);98 sg_init_one(&msg->sg_response, (u8 *)msg + sizeof(*msg) + request_size,99 response_size);100 101 INIT_LIST_HEAD(&msg->list);102 init_completion(&msg->notify);103 /* This reference is dropped in virtsnd_ctl_msg_complete(). */104 refcount_set(&msg->ref_count, 1);105 106 return msg;107}108 109/**110 * virtsnd_ctl_msg_send() - Send a control message.111 * @snd: VirtIO sound device.112 * @msg: Control message.113 * @out_sgs: Additional sg-list to attach to the request header (may be NULL).114 * @in_sgs: Additional sg-list to attach to the response header (may be NULL).115 * @nowait: Flag indicating whether to wait for completion.116 *117 * Context: Any context. Takes and releases the control queue spinlock.118 * May sleep if @nowait is false.119 * Return: 0 on success, -errno on failure.120 */121int virtsnd_ctl_msg_send(struct virtio_snd *snd, struct virtio_snd_msg *msg,122 struct scatterlist *out_sgs,123 struct scatterlist *in_sgs, bool nowait)124{125 struct virtio_device *vdev = snd->vdev;126 struct virtio_snd_queue *queue = virtsnd_control_queue(snd);127 unsigned int js = msecs_to_jiffies(virtsnd_msg_timeout_ms);128 struct virtio_snd_hdr *request = virtsnd_ctl_msg_request(msg);129 struct virtio_snd_hdr *response = virtsnd_ctl_msg_response(msg);130 unsigned int nouts = 0;131 unsigned int nins = 0;132 struct scatterlist *psgs[4];133 bool notify = false;134 unsigned long flags;135 int rc;136 137 virtsnd_ctl_msg_ref(msg);138 139 /* Set the default status in case the message was canceled. */140 response->code = cpu_to_le32(VIRTIO_SND_S_IO_ERR);141 142 psgs[nouts++] = &msg->sg_request;143 if (out_sgs)144 psgs[nouts++] = out_sgs;145 146 psgs[nouts + nins++] = &msg->sg_response;147 if (in_sgs)148 psgs[nouts + nins++] = in_sgs;149 150 spin_lock_irqsave(&queue->lock, flags);151 rc = virtqueue_add_sgs(queue->vqueue, psgs, nouts, nins, msg,152 GFP_ATOMIC);153 if (!rc) {154 notify = virtqueue_kick_prepare(queue->vqueue);155 156 list_add_tail(&msg->list, &snd->ctl_msgs);157 }158 spin_unlock_irqrestore(&queue->lock, flags);159 160 if (rc) {161 dev_err(&vdev->dev, "failed to send control message (0x%08x)\n",162 le32_to_cpu(request->code));163 164 /*165 * Since in this case virtsnd_ctl_msg_complete() will not be166 * called, it is necessary to decrement the reference count.167 */168 virtsnd_ctl_msg_unref(msg);169 170 goto on_exit;171 }172 173 if (notify)174 virtqueue_notify(queue->vqueue);175 176 if (nowait)177 goto on_exit;178 179 rc = wait_for_completion_interruptible_timeout(&msg->notify, js);180 if (rc <= 0) {181 if (!rc) {182 dev_err(&vdev->dev,183 "control message (0x%08x) timeout\n",184 le32_to_cpu(request->code));185 rc = -ETIMEDOUT;186 }187 188 goto on_exit;189 }190 191 switch (le32_to_cpu(response->code)) {192 case VIRTIO_SND_S_OK:193 rc = 0;194 break;195 case VIRTIO_SND_S_NOT_SUPP:196 rc = -EOPNOTSUPP;197 break;198 case VIRTIO_SND_S_IO_ERR:199 rc = -EIO;200 break;201 default:202 rc = -EINVAL;203 break;204 }205 206on_exit:207 virtsnd_ctl_msg_unref(msg);208 209 return rc;210}211 212/**213 * virtsnd_ctl_msg_complete() - Complete a control message.214 * @msg: Control message.215 *216 * Context: Any context. Expects the control queue spinlock to be held by217 * caller.218 */219void virtsnd_ctl_msg_complete(struct virtio_snd_msg *msg)220{221 list_del(&msg->list);222 complete(&msg->notify);223 224 virtsnd_ctl_msg_unref(msg);225}226 227/**228 * virtsnd_ctl_msg_cancel_all() - Cancel all pending control messages.229 * @snd: VirtIO sound device.230 *231 * Context: Any context.232 */233void virtsnd_ctl_msg_cancel_all(struct virtio_snd *snd)234{235 struct virtio_snd_queue *queue = virtsnd_control_queue(snd);236 unsigned long flags;237 238 spin_lock_irqsave(&queue->lock, flags);239 while (!list_empty(&snd->ctl_msgs)) {240 struct virtio_snd_msg *msg =241 list_first_entry(&snd->ctl_msgs, struct virtio_snd_msg,242 list);243 244 virtsnd_ctl_msg_complete(msg);245 }246 spin_unlock_irqrestore(&queue->lock, flags);247}248 249/**250 * virtsnd_ctl_query_info() - Query the item configuration from the device.251 * @snd: VirtIO sound device.252 * @command: Control request code (VIRTIO_SND_R_XXX_INFO).253 * @start_id: Item start identifier.254 * @count: Item count to query.255 * @size: Item information size in bytes.256 * @info: Buffer for storing item information.257 *258 * Context: Any context that permits to sleep.259 * Return: 0 on success, -errno on failure.260 */261int virtsnd_ctl_query_info(struct virtio_snd *snd, int command, int start_id,262 int count, size_t size, void *info)263{264 struct virtio_snd_msg *msg;265 struct virtio_snd_query_info *query;266 struct scatterlist sg;267 268 msg = virtsnd_ctl_msg_alloc(sizeof(*query),269 sizeof(struct virtio_snd_hdr), GFP_KERNEL);270 if (!msg)271 return -ENOMEM;272 273 query = virtsnd_ctl_msg_request(msg);274 query->hdr.code = cpu_to_le32(command);275 query->start_id = cpu_to_le32(start_id);276 query->count = cpu_to_le32(count);277 query->size = cpu_to_le32(size);278 279 sg_init_one(&sg, info, count * size);280 281 return virtsnd_ctl_msg_send(snd, msg, NULL, &sg, false);282}283 284/**285 * virtsnd_ctl_notify_cb() - Process all completed control messages.286 * @vqueue: Underlying control virtqueue.287 *288 * This callback function is called upon a vring interrupt request from the289 * device.290 *291 * Context: Interrupt context. Takes and releases the control queue spinlock.292 */293void virtsnd_ctl_notify_cb(struct virtqueue *vqueue)294{295 struct virtio_snd *snd = vqueue->vdev->priv;296 struct virtio_snd_queue *queue = virtsnd_control_queue(snd);297 struct virtio_snd_msg *msg;298 u32 length;299 unsigned long flags;300 301 spin_lock_irqsave(&queue->lock, flags);302 do {303 virtqueue_disable_cb(vqueue);304 while ((msg = virtqueue_get_buf(vqueue, &length)))305 virtsnd_ctl_msg_complete(msg);306 } while (!virtqueue_enable_cb(vqueue));307 spin_unlock_irqrestore(&queue->lock, flags);308}309