1 | // SPDX-License-Identifier: GPL-2.0+ |
2 | /* |
3 | * uvc_queue.c -- USB Video Class driver - Buffers management |
4 | * |
5 | * Copyright (C) 2005-2010 |
6 | * Laurent Pinchart (laurent.pinchart@ideasonboard.com) |
7 | */ |
8 | |
9 | #include <linux/atomic.h> |
10 | #include <linux/kernel.h> |
11 | #include <linux/mm.h> |
12 | #include <linux/list.h> |
13 | #include <linux/module.h> |
14 | #include <linux/usb.h> |
15 | #include <linux/videodev2.h> |
16 | #include <linux/vmalloc.h> |
17 | #include <linux/wait.h> |
18 | |
19 | #include <media/v4l2-common.h> |
20 | #include <media/videobuf2-dma-sg.h> |
21 | #include <media/videobuf2-vmalloc.h> |
22 | |
23 | #include "uvc.h" |
24 | |
25 | /* ------------------------------------------------------------------------ |
26 | * Video buffers queue management. |
27 | * |
28 | * Video queues is initialized by uvcg_queue_init(). The function performs |
29 | * basic initialization of the uvc_video_queue struct and never fails. |
30 | * |
31 | * Video buffers are managed by videobuf2. The driver uses a mutex to protect |
32 | * the videobuf2 queue operations by serializing calls to videobuf2 and a |
33 | * spinlock to protect the IRQ queue that holds the buffers to be processed by |
34 | * the driver. |
35 | */ |
36 | |
37 | /* ----------------------------------------------------------------------------- |
38 | * videobuf2 queue operations |
39 | */ |
40 | |
41 | static int uvc_queue_setup(struct vb2_queue *vq, |
42 | unsigned int *nbuffers, unsigned int *nplanes, |
43 | unsigned int sizes[], struct device *alloc_devs[]) |
44 | { |
45 | struct uvc_video_queue *queue = vb2_get_drv_priv(q: vq); |
46 | struct uvc_video *video = container_of(queue, struct uvc_video, queue); |
47 | unsigned int req_size; |
48 | unsigned int nreq; |
49 | |
50 | if (*nbuffers > UVC_MAX_VIDEO_BUFFERS) |
51 | *nbuffers = UVC_MAX_VIDEO_BUFFERS; |
52 | |
53 | *nplanes = 1; |
54 | |
55 | sizes[0] = video->imagesize; |
56 | |
57 | req_size = video->ep->maxpacket |
58 | * max_t(unsigned int, video->ep->maxburst, 1) |
59 | * (video->ep->mult); |
60 | |
61 | /* We divide by two, to increase the chance to run |
62 | * into fewer requests for smaller framesizes. |
63 | */ |
64 | nreq = DIV_ROUND_UP(DIV_ROUND_UP(sizes[0], 2), req_size); |
65 | nreq = clamp(nreq, 4U, 64U); |
66 | video->uvc_num_requests = nreq; |
67 | |
68 | return 0; |
69 | } |
70 | |
71 | static int uvc_buffer_prepare(struct vb2_buffer *vb) |
72 | { |
73 | struct uvc_video_queue *queue = vb2_get_drv_priv(q: vb->vb2_queue); |
74 | struct vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb); |
75 | struct uvc_buffer *buf = container_of(vbuf, struct uvc_buffer, buf); |
76 | |
77 | if (vb->type == V4L2_BUF_TYPE_VIDEO_OUTPUT && |
78 | vb2_get_plane_payload(vb, plane_no: 0) > vb2_plane_size(vb, plane_no: 0)) { |
79 | uvc_trace(UVC_TRACE_CAPTURE, "[E] Bytes used out of bounds.\n" ); |
80 | return -EINVAL; |
81 | } |
82 | |
83 | if (unlikely(queue->flags & UVC_QUEUE_DISCONNECTED)) |
84 | return -ENODEV; |
85 | |
86 | buf->state = UVC_BUF_STATE_QUEUED; |
87 | if (queue->use_sg) { |
88 | buf->sgt = vb2_dma_sg_plane_desc(vb, plane_no: 0); |
89 | buf->sg = buf->sgt->sgl; |
90 | } else { |
91 | buf->mem = vb2_plane_vaddr(vb, plane_no: 0); |
92 | } |
93 | buf->length = vb2_plane_size(vb, plane_no: 0); |
94 | if (vb->type == V4L2_BUF_TYPE_VIDEO_CAPTURE) |
95 | buf->bytesused = 0; |
96 | else |
97 | buf->bytesused = vb2_get_plane_payload(vb, plane_no: 0); |
98 | |
99 | return 0; |
100 | } |
101 | |
102 | static void uvc_buffer_queue(struct vb2_buffer *vb) |
103 | { |
104 | struct uvc_video_queue *queue = vb2_get_drv_priv(q: vb->vb2_queue); |
105 | struct vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb); |
106 | struct uvc_buffer *buf = container_of(vbuf, struct uvc_buffer, buf); |
107 | unsigned long flags; |
108 | |
109 | spin_lock_irqsave(&queue->irqlock, flags); |
110 | |
111 | if (likely(!(queue->flags & UVC_QUEUE_DISCONNECTED))) { |
112 | list_add_tail(new: &buf->queue, head: &queue->irqqueue); |
113 | } else { |
114 | /* |
115 | * If the device is disconnected return the buffer to userspace |
116 | * directly. The next QBUF call will fail with -ENODEV. |
117 | */ |
118 | buf->state = UVC_BUF_STATE_ERROR; |
119 | vb2_buffer_done(vb, state: VB2_BUF_STATE_ERROR); |
120 | } |
121 | |
122 | spin_unlock_irqrestore(lock: &queue->irqlock, flags); |
123 | } |
124 | |
125 | static const struct vb2_ops uvc_queue_qops = { |
126 | .queue_setup = uvc_queue_setup, |
127 | .buf_prepare = uvc_buffer_prepare, |
128 | .buf_queue = uvc_buffer_queue, |
129 | .wait_prepare = vb2_ops_wait_prepare, |
130 | .wait_finish = vb2_ops_wait_finish, |
131 | }; |
132 | |
133 | int uvcg_queue_init(struct uvc_video_queue *queue, struct device *dev, enum v4l2_buf_type type, |
134 | struct mutex *lock) |
135 | { |
136 | struct uvc_video *video = container_of(queue, struct uvc_video, queue); |
137 | struct usb_composite_dev *cdev = video->uvc->func.config->cdev; |
138 | int ret; |
139 | |
140 | queue->queue.type = type; |
141 | queue->queue.io_modes = VB2_MMAP | VB2_USERPTR | VB2_DMABUF; |
142 | queue->queue.drv_priv = queue; |
143 | queue->queue.buf_struct_size = sizeof(struct uvc_buffer); |
144 | queue->queue.ops = &uvc_queue_qops; |
145 | queue->queue.lock = lock; |
146 | if (cdev->gadget->sg_supported) { |
147 | queue->queue.mem_ops = &vb2_dma_sg_memops; |
148 | queue->use_sg = 1; |
149 | } else { |
150 | queue->queue.mem_ops = &vb2_vmalloc_memops; |
151 | } |
152 | |
153 | queue->queue.timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_COPY |
154 | | V4L2_BUF_FLAG_TSTAMP_SRC_EOF; |
155 | queue->queue.dev = dev; |
156 | |
157 | ret = vb2_queue_init(q: &queue->queue); |
158 | if (ret) |
159 | return ret; |
160 | |
161 | spin_lock_init(&queue->irqlock); |
162 | INIT_LIST_HEAD(list: &queue->irqqueue); |
163 | queue->flags = 0; |
164 | |
165 | return 0; |
166 | } |
167 | |
168 | /* |
169 | * Free the video buffers. |
170 | */ |
171 | void uvcg_free_buffers(struct uvc_video_queue *queue) |
172 | { |
173 | vb2_queue_release(q: &queue->queue); |
174 | } |
175 | |
176 | /* |
177 | * Allocate the video buffers. |
178 | */ |
179 | int uvcg_alloc_buffers(struct uvc_video_queue *queue, |
180 | struct v4l2_requestbuffers *rb) |
181 | { |
182 | int ret; |
183 | |
184 | ret = vb2_reqbufs(q: &queue->queue, req: rb); |
185 | |
186 | return ret ? ret : rb->count; |
187 | } |
188 | |
189 | int uvcg_query_buffer(struct uvc_video_queue *queue, struct v4l2_buffer *buf) |
190 | { |
191 | return vb2_querybuf(q: &queue->queue, b: buf); |
192 | } |
193 | |
194 | int uvcg_queue_buffer(struct uvc_video_queue *queue, struct v4l2_buffer *buf) |
195 | { |
196 | return vb2_qbuf(q: &queue->queue, NULL, b: buf); |
197 | } |
198 | |
199 | /* |
200 | * Dequeue a video buffer. If nonblocking is false, block until a buffer is |
201 | * available. |
202 | */ |
203 | int uvcg_dequeue_buffer(struct uvc_video_queue *queue, struct v4l2_buffer *buf, |
204 | int nonblocking) |
205 | { |
206 | return vb2_dqbuf(q: &queue->queue, b: buf, nonblocking); |
207 | } |
208 | |
209 | /* |
210 | * Poll the video queue. |
211 | * |
212 | * This function implements video queue polling and is intended to be used by |
213 | * the device poll handler. |
214 | */ |
215 | __poll_t uvcg_queue_poll(struct uvc_video_queue *queue, struct file *file, |
216 | poll_table *wait) |
217 | { |
218 | return vb2_poll(q: &queue->queue, file, wait); |
219 | } |
220 | |
221 | int uvcg_queue_mmap(struct uvc_video_queue *queue, struct vm_area_struct *vma) |
222 | { |
223 | return vb2_mmap(q: &queue->queue, vma); |
224 | } |
225 | |
226 | #ifndef CONFIG_MMU |
227 | /* |
228 | * Get unmapped area. |
229 | * |
230 | * NO-MMU arch need this function to make mmap() work correctly. |
231 | */ |
232 | unsigned long uvcg_queue_get_unmapped_area(struct uvc_video_queue *queue, |
233 | unsigned long pgoff) |
234 | { |
235 | return vb2_get_unmapped_area(&queue->queue, 0, 0, pgoff, 0); |
236 | } |
237 | #endif |
238 | |
239 | /* |
240 | * Cancel the video buffers queue. |
241 | * |
242 | * Cancelling the queue marks all buffers on the irq queue as erroneous, |
243 | * wakes them up and removes them from the queue. |
244 | * |
245 | * If the disconnect parameter is set, further calls to uvc_queue_buffer will |
246 | * fail with -ENODEV. |
247 | * |
248 | * This function acquires the irq spinlock and can be called from interrupt |
249 | * context. |
250 | */ |
251 | void uvcg_queue_cancel(struct uvc_video_queue *queue, int disconnect) |
252 | { |
253 | struct uvc_buffer *buf; |
254 | unsigned long flags; |
255 | |
256 | spin_lock_irqsave(&queue->irqlock, flags); |
257 | while (!list_empty(head: &queue->irqqueue)) { |
258 | buf = list_first_entry(&queue->irqqueue, struct uvc_buffer, |
259 | queue); |
260 | list_del(entry: &buf->queue); |
261 | buf->state = UVC_BUF_STATE_ERROR; |
262 | vb2_buffer_done(vb: &buf->buf.vb2_buf, state: VB2_BUF_STATE_ERROR); |
263 | } |
264 | queue->buf_used = 0; |
265 | |
266 | /* |
267 | * This must be protected by the irqlock spinlock to avoid race |
268 | * conditions between uvc_queue_buffer and the disconnection event that |
269 | * could result in an interruptible wait in uvc_dequeue_buffer. Do not |
270 | * blindly replace this logic by checking for the UVC_DEV_DISCONNECTED |
271 | * state outside the queue code. |
272 | */ |
273 | if (disconnect) |
274 | queue->flags |= UVC_QUEUE_DISCONNECTED; |
275 | spin_unlock_irqrestore(lock: &queue->irqlock, flags); |
276 | } |
277 | |
278 | /* |
279 | * Enable or disable the video buffers queue. |
280 | * |
281 | * The queue must be enabled before starting video acquisition and must be |
282 | * disabled after stopping it. This ensures that the video buffers queue |
283 | * state can be properly initialized before buffers are accessed from the |
284 | * interrupt handler. |
285 | * |
286 | * Enabling the video queue initializes parameters (such as sequence number, |
287 | * sync pattern, ...). If the queue is already enabled, return -EBUSY. |
288 | * |
289 | * Disabling the video queue cancels the queue and removes all buffers from |
290 | * the main queue. |
291 | * |
292 | * This function can't be called from interrupt context. Use |
293 | * uvcg_queue_cancel() instead. |
294 | */ |
295 | int uvcg_queue_enable(struct uvc_video_queue *queue, int enable) |
296 | { |
297 | unsigned long flags; |
298 | int ret = 0; |
299 | |
300 | if (enable) { |
301 | ret = vb2_streamon(q: &queue->queue, type: queue->queue.type); |
302 | if (ret < 0) |
303 | return ret; |
304 | |
305 | queue->sequence = 0; |
306 | queue->buf_used = 0; |
307 | queue->flags &= ~UVC_QUEUE_DROP_INCOMPLETE; |
308 | } else { |
309 | ret = vb2_streamoff(q: &queue->queue, type: queue->queue.type); |
310 | if (ret < 0) |
311 | return ret; |
312 | |
313 | spin_lock_irqsave(&queue->irqlock, flags); |
314 | INIT_LIST_HEAD(list: &queue->irqqueue); |
315 | |
316 | /* |
317 | * FIXME: We need to clear the DISCONNECTED flag to ensure that |
318 | * applications will be able to queue buffers for the next |
319 | * streaming run. However, clearing it here doesn't guarantee |
320 | * that the device will be reconnected in the meantime. |
321 | */ |
322 | queue->flags &= ~UVC_QUEUE_DISCONNECTED; |
323 | spin_unlock_irqrestore(lock: &queue->irqlock, flags); |
324 | } |
325 | |
326 | return ret; |
327 | } |
328 | |
329 | /* called with &queue_irqlock held.. */ |
330 | void uvcg_complete_buffer(struct uvc_video_queue *queue, |
331 | struct uvc_buffer *buf) |
332 | { |
333 | if (queue->flags & UVC_QUEUE_DROP_INCOMPLETE) { |
334 | queue->flags &= ~UVC_QUEUE_DROP_INCOMPLETE; |
335 | buf->state = UVC_BUF_STATE_ERROR; |
336 | vb2_set_plane_payload(vb: &buf->buf.vb2_buf, plane_no: 0, size: 0); |
337 | vb2_buffer_done(vb: &buf->buf.vb2_buf, state: VB2_BUF_STATE_ERROR); |
338 | return; |
339 | } |
340 | |
341 | buf->buf.field = V4L2_FIELD_NONE; |
342 | buf->buf.sequence = queue->sequence++; |
343 | buf->buf.vb2_buf.timestamp = ktime_get_ns(); |
344 | |
345 | vb2_set_plane_payload(vb: &buf->buf.vb2_buf, plane_no: 0, size: buf->bytesused); |
346 | vb2_buffer_done(vb: &buf->buf.vb2_buf, state: VB2_BUF_STATE_DONE); |
347 | } |
348 | |
349 | struct uvc_buffer *uvcg_queue_head(struct uvc_video_queue *queue) |
350 | { |
351 | struct uvc_buffer *buf = NULL; |
352 | |
353 | if (!list_empty(head: &queue->irqqueue)) |
354 | buf = list_first_entry(&queue->irqqueue, struct uvc_buffer, |
355 | queue); |
356 | |
357 | return buf; |
358 | } |
359 | |
360 | |