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-vmalloc.h> 21 22 #include "uvc.h" 23 24 /* ------------------------------------------------------------------------ 25 * Video buffers queue management. 26 * 27 * Video queues is initialized by uvcg_queue_init(). The function performs 28 * basic initialization of the uvc_video_queue struct and never fails. 29 * 30 * Video buffers are managed by videobuf2. The driver uses a mutex to protect 31 * the videobuf2 queue operations by serializing calls to videobuf2 and a 32 * spinlock to protect the IRQ queue that holds the buffers to be processed by 33 * the driver. 34 */ 35 36 /* ----------------------------------------------------------------------------- 37 * videobuf2 queue operations 38 */ 39 40 static int uvc_queue_setup(struct vb2_queue *vq, 41 unsigned int *nbuffers, unsigned int *nplanes, 42 unsigned int sizes[], struct device *alloc_devs[]) 43 { 44 struct uvc_video_queue *queue = vb2_get_drv_priv(vq); 45 struct uvc_video *video = container_of(queue, struct uvc_video, queue); 46 47 if (*nbuffers > UVC_MAX_VIDEO_BUFFERS) 48 *nbuffers = UVC_MAX_VIDEO_BUFFERS; 49 50 *nplanes = 1; 51 52 sizes[0] = video->imagesize; 53 54 return 0; 55 } 56 57 static int uvc_buffer_prepare(struct vb2_buffer *vb) 58 { 59 struct uvc_video_queue *queue = vb2_get_drv_priv(vb->vb2_queue); 60 struct vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb); 61 struct uvc_buffer *buf = container_of(vbuf, struct uvc_buffer, buf); 62 63 if (vb->type == V4L2_BUF_TYPE_VIDEO_OUTPUT && 64 vb2_get_plane_payload(vb, 0) > vb2_plane_size(vb, 0)) { 65 uvc_trace(UVC_TRACE_CAPTURE, "[E] Bytes used out of bounds.\n"); 66 return -EINVAL; 67 } 68 69 if (unlikely(queue->flags & UVC_QUEUE_DISCONNECTED)) 70 return -ENODEV; 71 72 buf->state = UVC_BUF_STATE_QUEUED; 73 buf->mem = vb2_plane_vaddr(vb, 0); 74 buf->length = vb2_plane_size(vb, 0); 75 if (vb->type == V4L2_BUF_TYPE_VIDEO_CAPTURE) 76 buf->bytesused = 0; 77 else 78 buf->bytesused = vb2_get_plane_payload(vb, 0); 79 80 return 0; 81 } 82 83 static void uvc_buffer_queue(struct vb2_buffer *vb) 84 { 85 struct uvc_video_queue *queue = vb2_get_drv_priv(vb->vb2_queue); 86 struct vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb); 87 struct uvc_buffer *buf = container_of(vbuf, struct uvc_buffer, buf); 88 unsigned long flags; 89 90 spin_lock_irqsave(&queue->irqlock, flags); 91 92 if (likely(!(queue->flags & UVC_QUEUE_DISCONNECTED))) { 93 list_add_tail(&buf->queue, &queue->irqqueue); 94 } else { 95 /* If the device is disconnected return the buffer to userspace 96 * directly. The next QBUF call will fail with -ENODEV. 97 */ 98 buf->state = UVC_BUF_STATE_ERROR; 99 vb2_buffer_done(vb, VB2_BUF_STATE_ERROR); 100 } 101 102 spin_unlock_irqrestore(&queue->irqlock, flags); 103 } 104 105 static struct vb2_ops uvc_queue_qops = { 106 .queue_setup = uvc_queue_setup, 107 .buf_prepare = uvc_buffer_prepare, 108 .buf_queue = uvc_buffer_queue, 109 .wait_prepare = vb2_ops_wait_prepare, 110 .wait_finish = vb2_ops_wait_finish, 111 }; 112 113 int uvcg_queue_init(struct uvc_video_queue *queue, enum v4l2_buf_type type, 114 struct mutex *lock) 115 { 116 int ret; 117 118 queue->queue.type = type; 119 queue->queue.io_modes = VB2_MMAP | VB2_USERPTR | VB2_DMABUF; 120 queue->queue.drv_priv = queue; 121 queue->queue.buf_struct_size = sizeof(struct uvc_buffer); 122 queue->queue.ops = &uvc_queue_qops; 123 queue->queue.lock = lock; 124 queue->queue.mem_ops = &vb2_vmalloc_memops; 125 queue->queue.timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC 126 | V4L2_BUF_FLAG_TSTAMP_SRC_EOF; 127 ret = vb2_queue_init(&queue->queue); 128 if (ret) 129 return ret; 130 131 spin_lock_init(&queue->irqlock); 132 INIT_LIST_HEAD(&queue->irqqueue); 133 queue->flags = 0; 134 135 return 0; 136 } 137 138 /* 139 * Free the video buffers. 140 */ 141 void uvcg_free_buffers(struct uvc_video_queue *queue) 142 { 143 vb2_queue_release(&queue->queue); 144 } 145 146 /* 147 * Allocate the video buffers. 148 */ 149 int uvcg_alloc_buffers(struct uvc_video_queue *queue, 150 struct v4l2_requestbuffers *rb) 151 { 152 int ret; 153 154 ret = vb2_reqbufs(&queue->queue, rb); 155 156 return ret ? ret : rb->count; 157 } 158 159 int uvcg_query_buffer(struct uvc_video_queue *queue, struct v4l2_buffer *buf) 160 { 161 return vb2_querybuf(&queue->queue, buf); 162 } 163 164 int uvcg_queue_buffer(struct uvc_video_queue *queue, struct v4l2_buffer *buf) 165 { 166 unsigned long flags; 167 int ret; 168 169 ret = vb2_qbuf(&queue->queue, buf); 170 if (ret < 0) 171 return ret; 172 173 spin_lock_irqsave(&queue->irqlock, flags); 174 ret = (queue->flags & UVC_QUEUE_PAUSED) != 0; 175 queue->flags &= ~UVC_QUEUE_PAUSED; 176 spin_unlock_irqrestore(&queue->irqlock, flags); 177 return ret; 178 } 179 180 /* 181 * Dequeue a video buffer. If nonblocking is false, block until a buffer is 182 * available. 183 */ 184 int uvcg_dequeue_buffer(struct uvc_video_queue *queue, struct v4l2_buffer *buf, 185 int nonblocking) 186 { 187 return vb2_dqbuf(&queue->queue, buf, nonblocking); 188 } 189 190 /* 191 * Poll the video queue. 192 * 193 * This function implements video queue polling and is intended to be used by 194 * the device poll handler. 195 */ 196 __poll_t uvcg_queue_poll(struct uvc_video_queue *queue, struct file *file, 197 poll_table *wait) 198 { 199 return vb2_poll(&queue->queue, file, wait); 200 } 201 202 int uvcg_queue_mmap(struct uvc_video_queue *queue, struct vm_area_struct *vma) 203 { 204 return vb2_mmap(&queue->queue, vma); 205 } 206 207 #ifndef CONFIG_MMU 208 /* 209 * Get unmapped area. 210 * 211 * NO-MMU arch need this function to make mmap() work correctly. 212 */ 213 unsigned long uvcg_queue_get_unmapped_area(struct uvc_video_queue *queue, 214 unsigned long pgoff) 215 { 216 return vb2_get_unmapped_area(&queue->queue, 0, 0, pgoff, 0); 217 } 218 #endif 219 220 /* 221 * Cancel the video buffers queue. 222 * 223 * Cancelling the queue marks all buffers on the irq queue as erroneous, 224 * wakes them up and removes them from the queue. 225 * 226 * If the disconnect parameter is set, further calls to uvc_queue_buffer will 227 * fail with -ENODEV. 228 * 229 * This function acquires the irq spinlock and can be called from interrupt 230 * context. 231 */ 232 void uvcg_queue_cancel(struct uvc_video_queue *queue, int disconnect) 233 { 234 struct uvc_buffer *buf; 235 unsigned long flags; 236 237 spin_lock_irqsave(&queue->irqlock, flags); 238 while (!list_empty(&queue->irqqueue)) { 239 buf = list_first_entry(&queue->irqqueue, struct uvc_buffer, 240 queue); 241 list_del(&buf->queue); 242 buf->state = UVC_BUF_STATE_ERROR; 243 vb2_buffer_done(&buf->buf.vb2_buf, VB2_BUF_STATE_ERROR); 244 } 245 /* This must be protected by the irqlock spinlock to avoid race 246 * conditions between uvc_queue_buffer and the disconnection event that 247 * could result in an interruptible wait in uvc_dequeue_buffer. Do not 248 * blindly replace this logic by checking for the UVC_DEV_DISCONNECTED 249 * state outside the queue code. 250 */ 251 if (disconnect) 252 queue->flags |= UVC_QUEUE_DISCONNECTED; 253 spin_unlock_irqrestore(&queue->irqlock, flags); 254 } 255 256 /* 257 * Enable or disable the video buffers queue. 258 * 259 * The queue must be enabled before starting video acquisition and must be 260 * disabled after stopping it. This ensures that the video buffers queue 261 * state can be properly initialized before buffers are accessed from the 262 * interrupt handler. 263 * 264 * Enabling the video queue initializes parameters (such as sequence number, 265 * sync pattern, ...). If the queue is already enabled, return -EBUSY. 266 * 267 * Disabling the video queue cancels the queue and removes all buffers from 268 * the main queue. 269 * 270 * This function can't be called from interrupt context. Use 271 * uvcg_queue_cancel() instead. 272 */ 273 int uvcg_queue_enable(struct uvc_video_queue *queue, int enable) 274 { 275 unsigned long flags; 276 int ret = 0; 277 278 if (enable) { 279 ret = vb2_streamon(&queue->queue, queue->queue.type); 280 if (ret < 0) 281 return ret; 282 283 queue->sequence = 0; 284 queue->buf_used = 0; 285 } else { 286 ret = vb2_streamoff(&queue->queue, queue->queue.type); 287 if (ret < 0) 288 return ret; 289 290 spin_lock_irqsave(&queue->irqlock, flags); 291 INIT_LIST_HEAD(&queue->irqqueue); 292 293 /* 294 * FIXME: We need to clear the DISCONNECTED flag to ensure that 295 * applications will be able to queue buffers for the next 296 * streaming run. However, clearing it here doesn't guarantee 297 * that the device will be reconnected in the meantime. 298 */ 299 queue->flags &= ~UVC_QUEUE_DISCONNECTED; 300 spin_unlock_irqrestore(&queue->irqlock, flags); 301 } 302 303 return ret; 304 } 305 306 /* called with &queue_irqlock held.. */ 307 struct uvc_buffer *uvcg_queue_next_buffer(struct uvc_video_queue *queue, 308 struct uvc_buffer *buf) 309 { 310 struct uvc_buffer *nextbuf; 311 312 if ((queue->flags & UVC_QUEUE_DROP_INCOMPLETE) && 313 buf->length != buf->bytesused) { 314 buf->state = UVC_BUF_STATE_QUEUED; 315 vb2_set_plane_payload(&buf->buf.vb2_buf, 0, 0); 316 return buf; 317 } 318 319 list_del(&buf->queue); 320 if (!list_empty(&queue->irqqueue)) 321 nextbuf = list_first_entry(&queue->irqqueue, struct uvc_buffer, 322 queue); 323 else 324 nextbuf = NULL; 325 326 buf->buf.field = V4L2_FIELD_NONE; 327 buf->buf.sequence = queue->sequence++; 328 buf->buf.vb2_buf.timestamp = ktime_get_ns(); 329 330 vb2_set_plane_payload(&buf->buf.vb2_buf, 0, buf->bytesused); 331 vb2_buffer_done(&buf->buf.vb2_buf, VB2_BUF_STATE_DONE); 332 333 return nextbuf; 334 } 335 336 struct uvc_buffer *uvcg_queue_head(struct uvc_video_queue *queue) 337 { 338 struct uvc_buffer *buf = NULL; 339 340 if (!list_empty(&queue->irqqueue)) 341 buf = list_first_entry(&queue->irqqueue, struct uvc_buffer, 342 queue); 343 else 344 queue->flags |= UVC_QUEUE_PAUSED; 345 346 return buf; 347 } 348 349