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 | */ |
19 | struct 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 | */ |
33 | void virtsnd_ctl_msg_ref(struct virtio_snd_msg *msg) |
34 | { |
35 | refcount_inc(r: &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 | */ |
46 | void virtsnd_ctl_msg_unref(struct virtio_snd_msg *msg) |
47 | { |
48 | if (refcount_dec_and_test(r: &msg->ref_count)) |
49 | kfree(objp: 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 | */ |
58 | void *virtsnd_ctl_msg_request(struct virtio_snd_msg *msg) |
59 | { |
60 | return sg_virt(sg: &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 | */ |
69 | void *virtsnd_ctl_msg_response(struct virtio_snd_msg *msg) |
70 | { |
71 | return sg_virt(sg: &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 | */ |
85 | struct 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(size: sizeof(*msg) + request_size + response_size, flags: 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(list: &msg->list); |
102 | init_completion(x: &msg->notify); |
103 | /* This reference is dropped in virtsnd_ctl_msg_complete(). */ |
104 | refcount_set(r: &msg->ref_count, n: 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 | */ |
121 | int 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(m: 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(vq: queue->vqueue, sgs: psgs, out_sgs: nouts, in_sgs: nins, data: msg, |
152 | GFP_ATOMIC); |
153 | if (!rc) { |
154 | notify = virtqueue_kick_prepare(vq: queue->vqueue); |
155 | |
156 | list_add_tail(new: &msg->list, head: &snd->ctl_msgs); |
157 | } |
158 | spin_unlock_irqrestore(lock: &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 be |
166 | * 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(vq: queue->vqueue); |
175 | |
176 | if (nowait) |
177 | goto on_exit; |
178 | |
179 | rc = wait_for_completion_interruptible_timeout(x: &msg->notify, timeout: 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 | |
206 | on_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 by |
217 | * caller. |
218 | */ |
219 | void virtsnd_ctl_msg_complete(struct virtio_snd_msg *msg) |
220 | { |
221 | list_del(entry: &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 | */ |
233 | void 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(head: &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(lock: &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 | */ |
261 | int 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(request_size: sizeof(*query), |
269 | response_size: 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, in_sgs: &sg, nowait: 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 the |
289 | * device. |
290 | * |
291 | * Context: Interrupt context. Takes and releases the control queue spinlock. |
292 | */ |
293 | void 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(vq: vqueue); |
304 | while ((msg = virtqueue_get_buf(vq: vqueue, len: &length))) |
305 | virtsnd_ctl_msg_complete(msg); |
306 | } while (!virtqueue_enable_cb(vq: vqueue)); |
307 | spin_unlock_irqrestore(lock: &queue->lock, flags); |
308 | } |
309 | |