projects/linux·blob master · refs

303 lines · 7.7 KiB

1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * virtio-snd: Virtio sound device
4 * Copyright (C) 2021 OpenSynergy GmbH
5 */
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 int rc;
135
136 virtsnd_ctl_msg_ref(msg);
137
138 /* Set the default status in case the message was canceled. */
139 response->code = cpu_to_le32(VIRTIO_SND_S_IO_ERR);
140
141 psgs[nouts++] = &msg->sg_request;
142 if (out_sgs)
143 psgs[nouts++] = out_sgs;
144
145 psgs[nouts + nins++] = &msg->sg_response;
146 if (in_sgs)
147 psgs[nouts + nins++] = in_sgs;
148
149 scoped_guard(spinlock_irqsave, &queue->lock) {
150 rc = virtqueue_add_sgs(queue->vqueue, psgs, nouts, nins, msg,
151 GFP_ATOMIC);
152 if (!rc) {
153 notify = virtqueue_kick_prepare(queue->vqueue);
154
155 list_add_tail(&msg->list, &snd->ctl_msgs);
156 }
157 }
158
159 if (rc) {
160 dev_err(&vdev->dev, "failed to send control message (0x%08x)\n",
161 le32_to_cpu(request->code));
162
163 /*
164 * Since in this case virtsnd_ctl_msg_complete() will not be
165 * called, it is necessary to decrement the reference count.
166 */
167 virtsnd_ctl_msg_unref(msg);
168
169 goto on_exit;
170 }
171
172 if (notify)
173 virtqueue_notify(queue->vqueue);
174
175 if (nowait)
176 goto on_exit;
177
178 rc = wait_for_completion_interruptible_timeout(&msg->notify, js);
179 if (rc <= 0) {
180 if (!rc) {
181 dev_err(&vdev->dev,
182 "control message (0x%08x) timeout\n",
183 le32_to_cpu(request->code));
184 rc = -ETIMEDOUT;
185 }
186
187 goto on_exit;
188 }
189
190 switch (le32_to_cpu(response->code)) {
191 case VIRTIO_SND_S_OK:
192 rc = 0;
193 break;
194 case VIRTIO_SND_S_NOT_SUPP:
195 rc = -EOPNOTSUPP;
196 break;
197 case VIRTIO_SND_S_IO_ERR:
198 rc = -EIO;
199 break;
200 default:
201 rc = -EINVAL;
202 break;
203 }
204
205on_exit:
206 virtsnd_ctl_msg_unref(msg);
207
208 return rc;
209}
210
211/**
212 * virtsnd_ctl_msg_complete() - Complete a control message.
213 * @msg: Control message.
214 *
215 * Context: Any context. Expects the control queue spinlock to be held by
216 * caller.
217 */
218void virtsnd_ctl_msg_complete(struct virtio_snd_msg *msg)
219{
220 list_del(&msg->list);
221 complete(&msg->notify);
222
223 virtsnd_ctl_msg_unref(msg);
224}
225
226/**
227 * virtsnd_ctl_msg_cancel_all() - Cancel all pending control messages.
228 * @snd: VirtIO sound device.
229 *
230 * Context: Any context.
231 */
232void virtsnd_ctl_msg_cancel_all(struct virtio_snd *snd)
233{
234 struct virtio_snd_queue *queue = virtsnd_control_queue(snd);
235
236 guard(spinlock_irqsave)(&queue->lock);
237 while (!list_empty(&snd->ctl_msgs)) {
238 struct virtio_snd_msg *msg =
239 list_first_entry(&snd->ctl_msgs, struct virtio_snd_msg,
240 list);
241
242 virtsnd_ctl_msg_complete(msg);
243 }
244}
245
246/**
247 * virtsnd_ctl_query_info() - Query the item configuration from the device.
248 * @snd: VirtIO sound device.
249 * @command: Control request code (VIRTIO_SND_R_XXX_INFO).
250 * @start_id: Item start identifier.
251 * @count: Item count to query.
252 * @size: Item information size in bytes.
253 * @info: Buffer for storing item information.
254 *
255 * Context: Any context that permits to sleep.
256 * Return: 0 on success, -errno on failure.
257 */
258int virtsnd_ctl_query_info(struct virtio_snd *snd, int command, int start_id,
259 int count, size_t size, void *info)
260{
261 struct virtio_snd_msg *msg;
262 struct virtio_snd_query_info *query;
263 struct scatterlist sg;
264
265 msg = virtsnd_ctl_msg_alloc(sizeof(*query),
266 sizeof(struct virtio_snd_hdr), GFP_KERNEL);
267 if (!msg)
268 return -ENOMEM;
269
270 query = virtsnd_ctl_msg_request(msg);
271 query->hdr.code = cpu_to_le32(command);
272 query->start_id = cpu_to_le32(start_id);
273 query->count = cpu_to_le32(count);
274 query->size = cpu_to_le32(size);
275
276 sg_init_one(&sg, info, count * size);
277
278 return virtsnd_ctl_msg_send(snd, msg, NULL, &sg, false);
279}
280
281/**
282 * virtsnd_ctl_notify_cb() - Process all completed control messages.
283 * @vqueue: Underlying control virtqueue.
284 *
285 * This callback function is called upon a vring interrupt request from the
286 * device.
287 *
288 * Context: Interrupt context. Takes and releases the control queue spinlock.
289 */
290void virtsnd_ctl_notify_cb(struct virtqueue *vqueue)
291{
292 struct virtio_snd *snd = vqueue->vdev->priv;
293 struct virtio_snd_queue *queue = virtsnd_control_queue(snd);
294 struct virtio_snd_msg *msg;
295 u32 length;
296
297 guard(spinlock_irqsave)(&queue->lock);
298 do {
299 virtqueue_disable_cb(vqueue);
300 while ((msg = virtqueue_get_buf(vqueue, &length)))
301 virtsnd_ctl_msg_complete(msg);
302 } while (!virtqueue_enable_cb(vqueue));
303}