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0001 /*
0002  * videobuf2-v4l2.c - V4L2 driver helper framework
0003  *
0004  * Copyright (C) 2010 Samsung Electronics
0005  *
0006  * Author: Pawel Osciak <pawel@osciak.com>
0007  *     Marek Szyprowski <m.szyprowski@samsung.com>
0008  *
0009  * The vb2_thread implementation was based on code from videobuf-dvb.c:
0010  *  (c) 2004 Gerd Knorr <kraxel@bytesex.org> [SUSE Labs]
0011  *
0012  * This program is free software; you can redistribute it and/or modify
0013  * it under the terms of the GNU General Public License as published by
0014  * the Free Software Foundation.
0015  */
0016 
0017 #include <linux/device.h>
0018 #include <linux/err.h>
0019 #include <linux/freezer.h>
0020 #include <linux/kernel.h>
0021 #include <linux/kthread.h>
0022 #include <linux/mm.h>
0023 #include <linux/module.h>
0024 #include <linux/poll.h>
0025 #include <linux/sched.h>
0026 #include <linux/slab.h>
0027 
0028 #include <media/v4l2-common.h>
0029 #include <media/v4l2-dev.h>
0030 #include <media/v4l2-device.h>
0031 #include <media/v4l2-event.h>
0032 #include <media/v4l2-fh.h>
0033 
0034 #include <media/videobuf2-v4l2.h>
0035 
0036 static int debug;
0037 module_param(debug, int, 0644);
0038 
0039 #define dprintk(q, level, fmt, arg...)                        \
0040     do {                                      \
0041         if (debug >= level)                       \
0042             pr_info("vb2-v4l2: [%p] %s: " fmt,            \
0043                 (q)->name, __func__, ## arg);             \
0044     } while (0)
0045 
0046 /* Flags that are set by us */
0047 #define V4L2_BUFFER_MASK_FLAGS  (V4L2_BUF_FLAG_MAPPED | V4L2_BUF_FLAG_QUEUED | \
0048                  V4L2_BUF_FLAG_DONE | V4L2_BUF_FLAG_ERROR | \
0049                  V4L2_BUF_FLAG_PREPARED | \
0050                  V4L2_BUF_FLAG_IN_REQUEST | \
0051                  V4L2_BUF_FLAG_REQUEST_FD | \
0052                  V4L2_BUF_FLAG_TIMESTAMP_MASK)
0053 /* Output buffer flags that should be passed on to the driver */
0054 #define V4L2_BUFFER_OUT_FLAGS   (V4L2_BUF_FLAG_PFRAME | \
0055                  V4L2_BUF_FLAG_BFRAME | \
0056                  V4L2_BUF_FLAG_KEYFRAME | \
0057                  V4L2_BUF_FLAG_TIMECODE | \
0058                  V4L2_BUF_FLAG_M2M_HOLD_CAPTURE_BUF)
0059 
0060 /*
0061  * __verify_planes_array() - verify that the planes array passed in struct
0062  * v4l2_buffer from userspace can be safely used
0063  */
0064 static int __verify_planes_array(struct vb2_buffer *vb, const struct v4l2_buffer *b)
0065 {
0066     if (!V4L2_TYPE_IS_MULTIPLANAR(b->type))
0067         return 0;
0068 
0069     /* Is memory for copying plane information present? */
0070     if (b->m.planes == NULL) {
0071         dprintk(vb->vb2_queue, 1,
0072             "multi-planar buffer passed but planes array not provided\n");
0073         return -EINVAL;
0074     }
0075 
0076     if (b->length < vb->num_planes || b->length > VB2_MAX_PLANES) {
0077         dprintk(vb->vb2_queue, 1,
0078             "incorrect planes array length, expected %d, got %d\n",
0079             vb->num_planes, b->length);
0080         return -EINVAL;
0081     }
0082 
0083     return 0;
0084 }
0085 
0086 static int __verify_planes_array_core(struct vb2_buffer *vb, const void *pb)
0087 {
0088     return __verify_planes_array(vb, pb);
0089 }
0090 
0091 /*
0092  * __verify_length() - Verify that the bytesused value for each plane fits in
0093  * the plane length and that the data offset doesn't exceed the bytesused value.
0094  */
0095 static int __verify_length(struct vb2_buffer *vb, const struct v4l2_buffer *b)
0096 {
0097     unsigned int length;
0098     unsigned int bytesused;
0099     unsigned int plane;
0100 
0101     if (V4L2_TYPE_IS_CAPTURE(b->type))
0102         return 0;
0103 
0104     if (V4L2_TYPE_IS_MULTIPLANAR(b->type)) {
0105         for (plane = 0; plane < vb->num_planes; ++plane) {
0106             length = (b->memory == VB2_MEMORY_USERPTR ||
0107                   b->memory == VB2_MEMORY_DMABUF)
0108                    ? b->m.planes[plane].length
0109                 : vb->planes[plane].length;
0110             bytesused = b->m.planes[plane].bytesused
0111                   ? b->m.planes[plane].bytesused : length;
0112 
0113             if (b->m.planes[plane].bytesused > length)
0114                 return -EINVAL;
0115 
0116             if (b->m.planes[plane].data_offset > 0 &&
0117                 b->m.planes[plane].data_offset >= bytesused)
0118                 return -EINVAL;
0119         }
0120     } else {
0121         length = (b->memory == VB2_MEMORY_USERPTR)
0122             ? b->length : vb->planes[0].length;
0123 
0124         if (b->bytesused > length)
0125             return -EINVAL;
0126     }
0127 
0128     return 0;
0129 }
0130 
0131 /*
0132  * __init_vb2_v4l2_buffer() - initialize the vb2_v4l2_buffer struct
0133  */
0134 static void __init_vb2_v4l2_buffer(struct vb2_buffer *vb)
0135 {
0136     struct vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb);
0137 
0138     vbuf->request_fd = -1;
0139 }
0140 
0141 static void __copy_timestamp(struct vb2_buffer *vb, const void *pb)
0142 {
0143     const struct v4l2_buffer *b = pb;
0144     struct vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb);
0145     struct vb2_queue *q = vb->vb2_queue;
0146 
0147     if (q->is_output) {
0148         /*
0149          * For output buffers copy the timestamp if needed,
0150          * and the timecode field and flag if needed.
0151          */
0152         if (q->copy_timestamp)
0153             vb->timestamp = v4l2_buffer_get_timestamp(b);
0154         vbuf->flags |= b->flags & V4L2_BUF_FLAG_TIMECODE;
0155         if (b->flags & V4L2_BUF_FLAG_TIMECODE)
0156             vbuf->timecode = b->timecode;
0157     }
0158 };
0159 
0160 static void vb2_warn_zero_bytesused(struct vb2_buffer *vb)
0161 {
0162     static bool check_once;
0163 
0164     if (check_once)
0165         return;
0166 
0167     check_once = true;
0168 
0169     pr_warn("use of bytesused == 0 is deprecated and will be removed in the future,\n");
0170     if (vb->vb2_queue->allow_zero_bytesused)
0171         pr_warn("use VIDIOC_DECODER_CMD(V4L2_DEC_CMD_STOP) instead.\n");
0172     else
0173         pr_warn("use the actual size instead.\n");
0174 }
0175 
0176 static int vb2_fill_vb2_v4l2_buffer(struct vb2_buffer *vb, struct v4l2_buffer *b)
0177 {
0178     struct vb2_queue *q = vb->vb2_queue;
0179     struct vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb);
0180     struct vb2_plane *planes = vbuf->planes;
0181     unsigned int plane;
0182     int ret;
0183 
0184     ret = __verify_length(vb, b);
0185     if (ret < 0) {
0186         dprintk(q, 1, "plane parameters verification failed: %d\n", ret);
0187         return ret;
0188     }
0189     if (b->field == V4L2_FIELD_ALTERNATE && q->is_output) {
0190         /*
0191          * If the format's field is ALTERNATE, then the buffer's field
0192          * should be either TOP or BOTTOM, not ALTERNATE since that
0193          * makes no sense. The driver has to know whether the
0194          * buffer represents a top or a bottom field in order to
0195          * program any DMA correctly. Using ALTERNATE is wrong, since
0196          * that just says that it is either a top or a bottom field,
0197          * but not which of the two it is.
0198          */
0199         dprintk(q, 1, "the field is incorrectly set to ALTERNATE for an output buffer\n");
0200         return -EINVAL;
0201     }
0202     vbuf->sequence = 0;
0203     vbuf->request_fd = -1;
0204     vbuf->is_held = false;
0205 
0206     if (V4L2_TYPE_IS_MULTIPLANAR(b->type)) {
0207         switch (b->memory) {
0208         case VB2_MEMORY_USERPTR:
0209             for (plane = 0; plane < vb->num_planes; ++plane) {
0210                 planes[plane].m.userptr =
0211                     b->m.planes[plane].m.userptr;
0212                 planes[plane].length =
0213                     b->m.planes[plane].length;
0214             }
0215             break;
0216         case VB2_MEMORY_DMABUF:
0217             for (plane = 0; plane < vb->num_planes; ++plane) {
0218                 planes[plane].m.fd =
0219                     b->m.planes[plane].m.fd;
0220                 planes[plane].length =
0221                     b->m.planes[plane].length;
0222             }
0223             break;
0224         default:
0225             for (plane = 0; plane < vb->num_planes; ++plane) {
0226                 planes[plane].m.offset =
0227                     vb->planes[plane].m.offset;
0228                 planes[plane].length =
0229                     vb->planes[plane].length;
0230             }
0231             break;
0232         }
0233 
0234         /* Fill in driver-provided information for OUTPUT types */
0235         if (V4L2_TYPE_IS_OUTPUT(b->type)) {
0236             /*
0237              * Will have to go up to b->length when API starts
0238              * accepting variable number of planes.
0239              *
0240              * If bytesused == 0 for the output buffer, then fall
0241              * back to the full buffer size. In that case
0242              * userspace clearly never bothered to set it and
0243              * it's a safe assumption that they really meant to
0244              * use the full plane sizes.
0245              *
0246              * Some drivers, e.g. old codec drivers, use bytesused == 0
0247              * as a way to indicate that streaming is finished.
0248              * In that case, the driver should use the
0249              * allow_zero_bytesused flag to keep old userspace
0250              * applications working.
0251              */
0252             for (plane = 0; plane < vb->num_planes; ++plane) {
0253                 struct vb2_plane *pdst = &planes[plane];
0254                 struct v4l2_plane *psrc = &b->m.planes[plane];
0255 
0256                 if (psrc->bytesused == 0)
0257                     vb2_warn_zero_bytesused(vb);
0258 
0259                 if (vb->vb2_queue->allow_zero_bytesused)
0260                     pdst->bytesused = psrc->bytesused;
0261                 else
0262                     pdst->bytesused = psrc->bytesused ?
0263                         psrc->bytesused : pdst->length;
0264                 pdst->data_offset = psrc->data_offset;
0265             }
0266         }
0267     } else {
0268         /*
0269          * Single-planar buffers do not use planes array,
0270          * so fill in relevant v4l2_buffer struct fields instead.
0271          * In videobuf we use our internal V4l2_planes struct for
0272          * single-planar buffers as well, for simplicity.
0273          *
0274          * If bytesused == 0 for the output buffer, then fall back
0275          * to the full buffer size as that's a sensible default.
0276          *
0277          * Some drivers, e.g. old codec drivers, use bytesused == 0 as
0278          * a way to indicate that streaming is finished. In that case,
0279          * the driver should use the allow_zero_bytesused flag to keep
0280          * old userspace applications working.
0281          */
0282         switch (b->memory) {
0283         case VB2_MEMORY_USERPTR:
0284             planes[0].m.userptr = b->m.userptr;
0285             planes[0].length = b->length;
0286             break;
0287         case VB2_MEMORY_DMABUF:
0288             planes[0].m.fd = b->m.fd;
0289             planes[0].length = b->length;
0290             break;
0291         default:
0292             planes[0].m.offset = vb->planes[0].m.offset;
0293             planes[0].length = vb->planes[0].length;
0294             break;
0295         }
0296 
0297         planes[0].data_offset = 0;
0298         if (V4L2_TYPE_IS_OUTPUT(b->type)) {
0299             if (b->bytesused == 0)
0300                 vb2_warn_zero_bytesused(vb);
0301 
0302             if (vb->vb2_queue->allow_zero_bytesused)
0303                 planes[0].bytesused = b->bytesused;
0304             else
0305                 planes[0].bytesused = b->bytesused ?
0306                     b->bytesused : planes[0].length;
0307         } else
0308             planes[0].bytesused = 0;
0309 
0310     }
0311 
0312     /* Zero flags that we handle */
0313     vbuf->flags = b->flags & ~V4L2_BUFFER_MASK_FLAGS;
0314     if (!vb->vb2_queue->copy_timestamp || V4L2_TYPE_IS_CAPTURE(b->type)) {
0315         /*
0316          * Non-COPY timestamps and non-OUTPUT queues will get
0317          * their timestamp and timestamp source flags from the
0318          * queue.
0319          */
0320         vbuf->flags &= ~V4L2_BUF_FLAG_TSTAMP_SRC_MASK;
0321     }
0322 
0323     if (V4L2_TYPE_IS_OUTPUT(b->type)) {
0324         /*
0325          * For output buffers mask out the timecode flag:
0326          * this will be handled later in vb2_qbuf().
0327          * The 'field' is valid metadata for this output buffer
0328          * and so that needs to be copied here.
0329          */
0330         vbuf->flags &= ~V4L2_BUF_FLAG_TIMECODE;
0331         vbuf->field = b->field;
0332         if (!(q->subsystem_flags & VB2_V4L2_FL_SUPPORTS_M2M_HOLD_CAPTURE_BUF))
0333             vbuf->flags &= ~V4L2_BUF_FLAG_M2M_HOLD_CAPTURE_BUF;
0334     } else {
0335         /* Zero any output buffer flags as this is a capture buffer */
0336         vbuf->flags &= ~V4L2_BUFFER_OUT_FLAGS;
0337         /* Zero last flag, this is a signal from driver to userspace */
0338         vbuf->flags &= ~V4L2_BUF_FLAG_LAST;
0339     }
0340 
0341     return 0;
0342 }
0343 
0344 static void set_buffer_cache_hints(struct vb2_queue *q,
0345                    struct vb2_buffer *vb,
0346                    struct v4l2_buffer *b)
0347 {
0348     if (!vb2_queue_allows_cache_hints(q)) {
0349         /*
0350          * Clear buffer cache flags if queue does not support user
0351          * space hints. That's to indicate to userspace that these
0352          * flags won't work.
0353          */
0354         b->flags &= ~V4L2_BUF_FLAG_NO_CACHE_INVALIDATE;
0355         b->flags &= ~V4L2_BUF_FLAG_NO_CACHE_CLEAN;
0356         return;
0357     }
0358 
0359     if (b->flags & V4L2_BUF_FLAG_NO_CACHE_INVALIDATE)
0360         vb->skip_cache_sync_on_finish = 1;
0361 
0362     if (b->flags & V4L2_BUF_FLAG_NO_CACHE_CLEAN)
0363         vb->skip_cache_sync_on_prepare = 1;
0364 }
0365 
0366 static int vb2_queue_or_prepare_buf(struct vb2_queue *q, struct media_device *mdev,
0367                     struct v4l2_buffer *b, bool is_prepare,
0368                     struct media_request **p_req)
0369 {
0370     const char *opname = is_prepare ? "prepare_buf" : "qbuf";
0371     struct media_request *req;
0372     struct vb2_v4l2_buffer *vbuf;
0373     struct vb2_buffer *vb;
0374     int ret;
0375 
0376     if (b->type != q->type) {
0377         dprintk(q, 1, "%s: invalid buffer type\n", opname);
0378         return -EINVAL;
0379     }
0380 
0381     if (b->index >= q->num_buffers) {
0382         dprintk(q, 1, "%s: buffer index out of range\n", opname);
0383         return -EINVAL;
0384     }
0385 
0386     if (q->bufs[b->index] == NULL) {
0387         /* Should never happen */
0388         dprintk(q, 1, "%s: buffer is NULL\n", opname);
0389         return -EINVAL;
0390     }
0391 
0392     if (b->memory != q->memory) {
0393         dprintk(q, 1, "%s: invalid memory type\n", opname);
0394         return -EINVAL;
0395     }
0396 
0397     vb = q->bufs[b->index];
0398     vbuf = to_vb2_v4l2_buffer(vb);
0399     ret = __verify_planes_array(vb, b);
0400     if (ret)
0401         return ret;
0402 
0403     if (!is_prepare && (b->flags & V4L2_BUF_FLAG_REQUEST_FD) &&
0404         vb->state != VB2_BUF_STATE_DEQUEUED) {
0405         dprintk(q, 1, "%s: buffer is not in dequeued state\n", opname);
0406         return -EINVAL;
0407     }
0408 
0409     if (!vb->prepared) {
0410         set_buffer_cache_hints(q, vb, b);
0411         /* Copy relevant information provided by the userspace */
0412         memset(vbuf->planes, 0,
0413                sizeof(vbuf->planes[0]) * vb->num_planes);
0414         ret = vb2_fill_vb2_v4l2_buffer(vb, b);
0415         if (ret)
0416             return ret;
0417     }
0418 
0419     if (is_prepare)
0420         return 0;
0421 
0422     if (!(b->flags & V4L2_BUF_FLAG_REQUEST_FD)) {
0423         if (q->requires_requests) {
0424             dprintk(q, 1, "%s: queue requires requests\n", opname);
0425             return -EBADR;
0426         }
0427         if (q->uses_requests) {
0428             dprintk(q, 1, "%s: queue uses requests\n", opname);
0429             return -EBUSY;
0430         }
0431         return 0;
0432     } else if (!q->supports_requests) {
0433         dprintk(q, 1, "%s: queue does not support requests\n", opname);
0434         return -EBADR;
0435     } else if (q->uses_qbuf) {
0436         dprintk(q, 1, "%s: queue does not use requests\n", opname);
0437         return -EBUSY;
0438     }
0439 
0440     /*
0441      * For proper locking when queueing a request you need to be able
0442      * to lock access to the vb2 queue, so check that there is a lock
0443      * that we can use. In addition p_req must be non-NULL.
0444      */
0445     if (WARN_ON(!q->lock || !p_req))
0446         return -EINVAL;
0447 
0448     /*
0449      * Make sure this op is implemented by the driver. It's easy to forget
0450      * this callback, but is it important when canceling a buffer in a
0451      * queued request.
0452      */
0453     if (WARN_ON(!q->ops->buf_request_complete))
0454         return -EINVAL;
0455     /*
0456      * Make sure this op is implemented by the driver for the output queue.
0457      * It's easy to forget this callback, but is it important to correctly
0458      * validate the 'field' value at QBUF time.
0459      */
0460     if (WARN_ON((q->type == V4L2_BUF_TYPE_VIDEO_OUTPUT ||
0461              q->type == V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE) &&
0462             !q->ops->buf_out_validate))
0463         return -EINVAL;
0464 
0465     req = media_request_get_by_fd(mdev, b->request_fd);
0466     if (IS_ERR(req)) {
0467         dprintk(q, 1, "%s: invalid request_fd\n", opname);
0468         return PTR_ERR(req);
0469     }
0470 
0471     /*
0472      * Early sanity check. This is checked again when the buffer
0473      * is bound to the request in vb2_core_qbuf().
0474      */
0475     if (req->state != MEDIA_REQUEST_STATE_IDLE &&
0476         req->state != MEDIA_REQUEST_STATE_UPDATING) {
0477         dprintk(q, 1, "%s: request is not idle\n", opname);
0478         media_request_put(req);
0479         return -EBUSY;
0480     }
0481 
0482     *p_req = req;
0483     vbuf->request_fd = b->request_fd;
0484 
0485     return 0;
0486 }
0487 
0488 /*
0489  * __fill_v4l2_buffer() - fill in a struct v4l2_buffer with information to be
0490  * returned to userspace
0491  */
0492 static void __fill_v4l2_buffer(struct vb2_buffer *vb, void *pb)
0493 {
0494     struct v4l2_buffer *b = pb;
0495     struct vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb);
0496     struct vb2_queue *q = vb->vb2_queue;
0497     unsigned int plane;
0498 
0499     /* Copy back data such as timestamp, flags, etc. */
0500     b->index = vb->index;
0501     b->type = vb->type;
0502     b->memory = vb->memory;
0503     b->bytesused = 0;
0504 
0505     b->flags = vbuf->flags;
0506     b->field = vbuf->field;
0507     v4l2_buffer_set_timestamp(b, vb->timestamp);
0508     b->timecode = vbuf->timecode;
0509     b->sequence = vbuf->sequence;
0510     b->reserved2 = 0;
0511     b->request_fd = 0;
0512 
0513     if (q->is_multiplanar) {
0514         /*
0515          * Fill in plane-related data if userspace provided an array
0516          * for it. The caller has already verified memory and size.
0517          */
0518         b->length = vb->num_planes;
0519         for (plane = 0; plane < vb->num_planes; ++plane) {
0520             struct v4l2_plane *pdst = &b->m.planes[plane];
0521             struct vb2_plane *psrc = &vb->planes[plane];
0522 
0523             pdst->bytesused = psrc->bytesused;
0524             pdst->length = psrc->length;
0525             if (q->memory == VB2_MEMORY_MMAP)
0526                 pdst->m.mem_offset = psrc->m.offset;
0527             else if (q->memory == VB2_MEMORY_USERPTR)
0528                 pdst->m.userptr = psrc->m.userptr;
0529             else if (q->memory == VB2_MEMORY_DMABUF)
0530                 pdst->m.fd = psrc->m.fd;
0531             pdst->data_offset = psrc->data_offset;
0532             memset(pdst->reserved, 0, sizeof(pdst->reserved));
0533         }
0534     } else {
0535         /*
0536          * We use length and offset in v4l2_planes array even for
0537          * single-planar buffers, but userspace does not.
0538          */
0539         b->length = vb->planes[0].length;
0540         b->bytesused = vb->planes[0].bytesused;
0541         if (q->memory == VB2_MEMORY_MMAP)
0542             b->m.offset = vb->planes[0].m.offset;
0543         else if (q->memory == VB2_MEMORY_USERPTR)
0544             b->m.userptr = vb->planes[0].m.userptr;
0545         else if (q->memory == VB2_MEMORY_DMABUF)
0546             b->m.fd = vb->planes[0].m.fd;
0547     }
0548 
0549     /*
0550      * Clear any buffer state related flags.
0551      */
0552     b->flags &= ~V4L2_BUFFER_MASK_FLAGS;
0553     b->flags |= q->timestamp_flags & V4L2_BUF_FLAG_TIMESTAMP_MASK;
0554     if (!q->copy_timestamp) {
0555         /*
0556          * For non-COPY timestamps, drop timestamp source bits
0557          * and obtain the timestamp source from the queue.
0558          */
0559         b->flags &= ~V4L2_BUF_FLAG_TSTAMP_SRC_MASK;
0560         b->flags |= q->timestamp_flags & V4L2_BUF_FLAG_TSTAMP_SRC_MASK;
0561     }
0562 
0563     switch (vb->state) {
0564     case VB2_BUF_STATE_QUEUED:
0565     case VB2_BUF_STATE_ACTIVE:
0566         b->flags |= V4L2_BUF_FLAG_QUEUED;
0567         break;
0568     case VB2_BUF_STATE_IN_REQUEST:
0569         b->flags |= V4L2_BUF_FLAG_IN_REQUEST;
0570         break;
0571     case VB2_BUF_STATE_ERROR:
0572         b->flags |= V4L2_BUF_FLAG_ERROR;
0573         fallthrough;
0574     case VB2_BUF_STATE_DONE:
0575         b->flags |= V4L2_BUF_FLAG_DONE;
0576         break;
0577     case VB2_BUF_STATE_PREPARING:
0578     case VB2_BUF_STATE_DEQUEUED:
0579         /* nothing */
0580         break;
0581     }
0582 
0583     if ((vb->state == VB2_BUF_STATE_DEQUEUED ||
0584          vb->state == VB2_BUF_STATE_IN_REQUEST) &&
0585         vb->synced && vb->prepared)
0586         b->flags |= V4L2_BUF_FLAG_PREPARED;
0587 
0588     if (vb2_buffer_in_use(q, vb))
0589         b->flags |= V4L2_BUF_FLAG_MAPPED;
0590     if (vbuf->request_fd >= 0) {
0591         b->flags |= V4L2_BUF_FLAG_REQUEST_FD;
0592         b->request_fd = vbuf->request_fd;
0593     }
0594 }
0595 
0596 /*
0597  * __fill_vb2_buffer() - fill a vb2_buffer with information provided in a
0598  * v4l2_buffer by the userspace. It also verifies that struct
0599  * v4l2_buffer has a valid number of planes.
0600  */
0601 static int __fill_vb2_buffer(struct vb2_buffer *vb, struct vb2_plane *planes)
0602 {
0603     struct vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb);
0604     unsigned int plane;
0605 
0606     if (!vb->vb2_queue->copy_timestamp)
0607         vb->timestamp = 0;
0608 
0609     for (plane = 0; plane < vb->num_planes; ++plane) {
0610         if (vb->vb2_queue->memory != VB2_MEMORY_MMAP) {
0611             planes[plane].m = vbuf->planes[plane].m;
0612             planes[plane].length = vbuf->planes[plane].length;
0613         }
0614         planes[plane].bytesused = vbuf->planes[plane].bytesused;
0615         planes[plane].data_offset = vbuf->planes[plane].data_offset;
0616     }
0617     return 0;
0618 }
0619 
0620 static const struct vb2_buf_ops v4l2_buf_ops = {
0621     .verify_planes_array    = __verify_planes_array_core,
0622     .init_buffer        = __init_vb2_v4l2_buffer,
0623     .fill_user_buffer   = __fill_v4l2_buffer,
0624     .fill_vb2_buffer    = __fill_vb2_buffer,
0625     .copy_timestamp     = __copy_timestamp,
0626 };
0627 
0628 int vb2_find_timestamp(const struct vb2_queue *q, u64 timestamp,
0629                unsigned int start_idx)
0630 {
0631     unsigned int i;
0632 
0633     for (i = start_idx; i < q->num_buffers; i++)
0634         if (q->bufs[i]->copied_timestamp &&
0635             q->bufs[i]->timestamp == timestamp)
0636             return i;
0637     return -1;
0638 }
0639 EXPORT_SYMBOL_GPL(vb2_find_timestamp);
0640 
0641 struct vb2_buffer *vb2_find_buffer(struct vb2_queue *q, u64 timestamp)
0642 {
0643     unsigned int i;
0644 
0645     for (i = 0; i < q->num_buffers; i++)
0646         if (q->bufs[i]->copied_timestamp &&
0647             q->bufs[i]->timestamp == timestamp)
0648             return vb2_get_buffer(q, i);
0649     return NULL;
0650 }
0651 EXPORT_SYMBOL_GPL(vb2_find_buffer);
0652 
0653 /*
0654  * vb2_querybuf() - query video buffer information
0655  * @q:      videobuf queue
0656  * @b:      buffer struct passed from userspace to vidioc_querybuf handler
0657  *      in driver
0658  *
0659  * Should be called from vidioc_querybuf ioctl handler in driver.
0660  * This function will verify the passed v4l2_buffer structure and fill the
0661  * relevant information for the userspace.
0662  *
0663  * The return values from this function are intended to be directly returned
0664  * from vidioc_querybuf handler in driver.
0665  */
0666 int vb2_querybuf(struct vb2_queue *q, struct v4l2_buffer *b)
0667 {
0668     struct vb2_buffer *vb;
0669     int ret;
0670 
0671     if (b->type != q->type) {
0672         dprintk(q, 1, "wrong buffer type\n");
0673         return -EINVAL;
0674     }
0675 
0676     if (b->index >= q->num_buffers) {
0677         dprintk(q, 1, "buffer index out of range\n");
0678         return -EINVAL;
0679     }
0680     vb = q->bufs[b->index];
0681     ret = __verify_planes_array(vb, b);
0682     if (!ret)
0683         vb2_core_querybuf(q, b->index, b);
0684     return ret;
0685 }
0686 EXPORT_SYMBOL(vb2_querybuf);
0687 
0688 static void fill_buf_caps(struct vb2_queue *q, u32 *caps)
0689 {
0690     *caps = V4L2_BUF_CAP_SUPPORTS_ORPHANED_BUFS;
0691     if (q->io_modes & VB2_MMAP)
0692         *caps |= V4L2_BUF_CAP_SUPPORTS_MMAP;
0693     if (q->io_modes & VB2_USERPTR)
0694         *caps |= V4L2_BUF_CAP_SUPPORTS_USERPTR;
0695     if (q->io_modes & VB2_DMABUF)
0696         *caps |= V4L2_BUF_CAP_SUPPORTS_DMABUF;
0697     if (q->subsystem_flags & VB2_V4L2_FL_SUPPORTS_M2M_HOLD_CAPTURE_BUF)
0698         *caps |= V4L2_BUF_CAP_SUPPORTS_M2M_HOLD_CAPTURE_BUF;
0699     if (q->allow_cache_hints && q->io_modes & VB2_MMAP)
0700         *caps |= V4L2_BUF_CAP_SUPPORTS_MMAP_CACHE_HINTS;
0701 #ifdef CONFIG_MEDIA_CONTROLLER_REQUEST_API
0702     if (q->supports_requests)
0703         *caps |= V4L2_BUF_CAP_SUPPORTS_REQUESTS;
0704 #endif
0705 }
0706 
0707 static void validate_memory_flags(struct vb2_queue *q,
0708                   int memory,
0709                   u32 *flags)
0710 {
0711     if (!q->allow_cache_hints || memory != V4L2_MEMORY_MMAP) {
0712         /*
0713          * This needs to clear V4L2_MEMORY_FLAG_NON_COHERENT only,
0714          * but in order to avoid bugs we zero out all bits.
0715          */
0716         *flags = 0;
0717     } else {
0718         /* Clear all unknown flags. */
0719         *flags &= V4L2_MEMORY_FLAG_NON_COHERENT;
0720     }
0721 }
0722 
0723 int vb2_reqbufs(struct vb2_queue *q, struct v4l2_requestbuffers *req)
0724 {
0725     int ret = vb2_verify_memory_type(q, req->memory, req->type);
0726     u32 flags = req->flags;
0727 
0728     fill_buf_caps(q, &req->capabilities);
0729     validate_memory_flags(q, req->memory, &flags);
0730     req->flags = flags;
0731     return ret ? ret : vb2_core_reqbufs(q, req->memory,
0732                         req->flags, &req->count);
0733 }
0734 EXPORT_SYMBOL_GPL(vb2_reqbufs);
0735 
0736 int vb2_prepare_buf(struct vb2_queue *q, struct media_device *mdev,
0737             struct v4l2_buffer *b)
0738 {
0739     int ret;
0740 
0741     if (vb2_fileio_is_active(q)) {
0742         dprintk(q, 1, "file io in progress\n");
0743         return -EBUSY;
0744     }
0745 
0746     if (b->flags & V4L2_BUF_FLAG_REQUEST_FD)
0747         return -EINVAL;
0748 
0749     ret = vb2_queue_or_prepare_buf(q, mdev, b, true, NULL);
0750 
0751     return ret ? ret : vb2_core_prepare_buf(q, b->index, b);
0752 }
0753 EXPORT_SYMBOL_GPL(vb2_prepare_buf);
0754 
0755 int vb2_create_bufs(struct vb2_queue *q, struct v4l2_create_buffers *create)
0756 {
0757     unsigned requested_planes = 1;
0758     unsigned requested_sizes[VIDEO_MAX_PLANES];
0759     struct v4l2_format *f = &create->format;
0760     int ret = vb2_verify_memory_type(q, create->memory, f->type);
0761     unsigned i;
0762 
0763     fill_buf_caps(q, &create->capabilities);
0764     validate_memory_flags(q, create->memory, &create->flags);
0765     create->index = q->num_buffers;
0766     if (create->count == 0)
0767         return ret != -EBUSY ? ret : 0;
0768 
0769     switch (f->type) {
0770     case V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE:
0771     case V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE:
0772         requested_planes = f->fmt.pix_mp.num_planes;
0773         if (requested_planes == 0 ||
0774             requested_planes > VIDEO_MAX_PLANES)
0775             return -EINVAL;
0776         for (i = 0; i < requested_planes; i++)
0777             requested_sizes[i] =
0778                 f->fmt.pix_mp.plane_fmt[i].sizeimage;
0779         break;
0780     case V4L2_BUF_TYPE_VIDEO_CAPTURE:
0781     case V4L2_BUF_TYPE_VIDEO_OUTPUT:
0782         requested_sizes[0] = f->fmt.pix.sizeimage;
0783         break;
0784     case V4L2_BUF_TYPE_VBI_CAPTURE:
0785     case V4L2_BUF_TYPE_VBI_OUTPUT:
0786         requested_sizes[0] = f->fmt.vbi.samples_per_line *
0787             (f->fmt.vbi.count[0] + f->fmt.vbi.count[1]);
0788         break;
0789     case V4L2_BUF_TYPE_SLICED_VBI_CAPTURE:
0790     case V4L2_BUF_TYPE_SLICED_VBI_OUTPUT:
0791         requested_sizes[0] = f->fmt.sliced.io_size;
0792         break;
0793     case V4L2_BUF_TYPE_SDR_CAPTURE:
0794     case V4L2_BUF_TYPE_SDR_OUTPUT:
0795         requested_sizes[0] = f->fmt.sdr.buffersize;
0796         break;
0797     case V4L2_BUF_TYPE_META_CAPTURE:
0798     case V4L2_BUF_TYPE_META_OUTPUT:
0799         requested_sizes[0] = f->fmt.meta.buffersize;
0800         break;
0801     default:
0802         return -EINVAL;
0803     }
0804     for (i = 0; i < requested_planes; i++)
0805         if (requested_sizes[i] == 0)
0806             return -EINVAL;
0807     return ret ? ret : vb2_core_create_bufs(q, create->memory,
0808                         create->flags,
0809                         &create->count,
0810                         requested_planes,
0811                         requested_sizes);
0812 }
0813 EXPORT_SYMBOL_GPL(vb2_create_bufs);
0814 
0815 int vb2_qbuf(struct vb2_queue *q, struct media_device *mdev,
0816          struct v4l2_buffer *b)
0817 {
0818     struct media_request *req = NULL;
0819     int ret;
0820 
0821     if (vb2_fileio_is_active(q)) {
0822         dprintk(q, 1, "file io in progress\n");
0823         return -EBUSY;
0824     }
0825 
0826     ret = vb2_queue_or_prepare_buf(q, mdev, b, false, &req);
0827     if (ret)
0828         return ret;
0829     ret = vb2_core_qbuf(q, b->index, b, req);
0830     if (req)
0831         media_request_put(req);
0832     return ret;
0833 }
0834 EXPORT_SYMBOL_GPL(vb2_qbuf);
0835 
0836 int vb2_dqbuf(struct vb2_queue *q, struct v4l2_buffer *b, bool nonblocking)
0837 {
0838     int ret;
0839 
0840     if (vb2_fileio_is_active(q)) {
0841         dprintk(q, 1, "file io in progress\n");
0842         return -EBUSY;
0843     }
0844 
0845     if (b->type != q->type) {
0846         dprintk(q, 1, "invalid buffer type\n");
0847         return -EINVAL;
0848     }
0849 
0850     ret = vb2_core_dqbuf(q, NULL, b, nonblocking);
0851 
0852     if (!q->is_output &&
0853         b->flags & V4L2_BUF_FLAG_DONE &&
0854         b->flags & V4L2_BUF_FLAG_LAST)
0855         q->last_buffer_dequeued = true;
0856 
0857     /*
0858      *  After calling the VIDIOC_DQBUF V4L2_BUF_FLAG_DONE must be
0859      *  cleared.
0860      */
0861     b->flags &= ~V4L2_BUF_FLAG_DONE;
0862 
0863     return ret;
0864 }
0865 EXPORT_SYMBOL_GPL(vb2_dqbuf);
0866 
0867 int vb2_streamon(struct vb2_queue *q, enum v4l2_buf_type type)
0868 {
0869     if (vb2_fileio_is_active(q)) {
0870         dprintk(q, 1, "file io in progress\n");
0871         return -EBUSY;
0872     }
0873     return vb2_core_streamon(q, type);
0874 }
0875 EXPORT_SYMBOL_GPL(vb2_streamon);
0876 
0877 int vb2_streamoff(struct vb2_queue *q, enum v4l2_buf_type type)
0878 {
0879     if (vb2_fileio_is_active(q)) {
0880         dprintk(q, 1, "file io in progress\n");
0881         return -EBUSY;
0882     }
0883     return vb2_core_streamoff(q, type);
0884 }
0885 EXPORT_SYMBOL_GPL(vb2_streamoff);
0886 
0887 int vb2_expbuf(struct vb2_queue *q, struct v4l2_exportbuffer *eb)
0888 {
0889     return vb2_core_expbuf(q, &eb->fd, eb->type, eb->index,
0890                 eb->plane, eb->flags);
0891 }
0892 EXPORT_SYMBOL_GPL(vb2_expbuf);
0893 
0894 int vb2_queue_init_name(struct vb2_queue *q, const char *name)
0895 {
0896     /*
0897      * Sanity check
0898      */
0899     if (WARN_ON(!q)           ||
0900         WARN_ON(q->timestamp_flags &
0901             ~(V4L2_BUF_FLAG_TIMESTAMP_MASK |
0902               V4L2_BUF_FLAG_TSTAMP_SRC_MASK)))
0903         return -EINVAL;
0904 
0905     /* Warn that the driver should choose an appropriate timestamp type */
0906     WARN_ON((q->timestamp_flags & V4L2_BUF_FLAG_TIMESTAMP_MASK) ==
0907         V4L2_BUF_FLAG_TIMESTAMP_UNKNOWN);
0908 
0909     /* Warn that vb2_memory should match with v4l2_memory */
0910     if (WARN_ON(VB2_MEMORY_MMAP != (int)V4L2_MEMORY_MMAP)
0911         || WARN_ON(VB2_MEMORY_USERPTR != (int)V4L2_MEMORY_USERPTR)
0912         || WARN_ON(VB2_MEMORY_DMABUF != (int)V4L2_MEMORY_DMABUF))
0913         return -EINVAL;
0914 
0915     if (q->buf_struct_size == 0)
0916         q->buf_struct_size = sizeof(struct vb2_v4l2_buffer);
0917 
0918     q->buf_ops = &v4l2_buf_ops;
0919     q->is_multiplanar = V4L2_TYPE_IS_MULTIPLANAR(q->type);
0920     q->is_output = V4L2_TYPE_IS_OUTPUT(q->type);
0921     q->copy_timestamp = (q->timestamp_flags & V4L2_BUF_FLAG_TIMESTAMP_MASK)
0922             == V4L2_BUF_FLAG_TIMESTAMP_COPY;
0923     /*
0924      * For compatibility with vb1: if QBUF hasn't been called yet, then
0925      * return EPOLLERR as well. This only affects capture queues, output
0926      * queues will always initialize waiting_for_buffers to false.
0927      */
0928     q->quirk_poll_must_check_waiting_for_buffers = true;
0929 
0930     if (name)
0931         strscpy(q->name, name, sizeof(q->name));
0932     else
0933         q->name[0] = '\0';
0934 
0935     return vb2_core_queue_init(q);
0936 }
0937 EXPORT_SYMBOL_GPL(vb2_queue_init_name);
0938 
0939 int vb2_queue_init(struct vb2_queue *q)
0940 {
0941     return vb2_queue_init_name(q, NULL);
0942 }
0943 EXPORT_SYMBOL_GPL(vb2_queue_init);
0944 
0945 void vb2_queue_release(struct vb2_queue *q)
0946 {
0947     vb2_core_queue_release(q);
0948 }
0949 EXPORT_SYMBOL_GPL(vb2_queue_release);
0950 
0951 int vb2_queue_change_type(struct vb2_queue *q, unsigned int type)
0952 {
0953     if (type == q->type)
0954         return 0;
0955 
0956     if (vb2_is_busy(q))
0957         return -EBUSY;
0958 
0959     q->type = type;
0960 
0961     return 0;
0962 }
0963 EXPORT_SYMBOL_GPL(vb2_queue_change_type);
0964 
0965 __poll_t vb2_poll(struct vb2_queue *q, struct file *file, poll_table *wait)
0966 {
0967     struct video_device *vfd = video_devdata(file);
0968     __poll_t res;
0969 
0970     res = vb2_core_poll(q, file, wait);
0971 
0972     if (test_bit(V4L2_FL_USES_V4L2_FH, &vfd->flags)) {
0973         struct v4l2_fh *fh = file->private_data;
0974 
0975         poll_wait(file, &fh->wait, wait);
0976         if (v4l2_event_pending(fh))
0977             res |= EPOLLPRI;
0978     }
0979 
0980     return res;
0981 }
0982 EXPORT_SYMBOL_GPL(vb2_poll);
0983 
0984 /*
0985  * The following functions are not part of the vb2 core API, but are helper
0986  * functions that plug into struct v4l2_ioctl_ops, struct v4l2_file_operations
0987  * and struct vb2_ops.
0988  * They contain boilerplate code that most if not all drivers have to do
0989  * and so they simplify the driver code.
0990  */
0991 
0992 /* vb2 ioctl helpers */
0993 
0994 int vb2_ioctl_reqbufs(struct file *file, void *priv,
0995               struct v4l2_requestbuffers *p)
0996 {
0997     struct video_device *vdev = video_devdata(file);
0998     int res = vb2_verify_memory_type(vdev->queue, p->memory, p->type);
0999     u32 flags = p->flags;
1000 
1001     fill_buf_caps(vdev->queue, &p->capabilities);
1002     validate_memory_flags(vdev->queue, p->memory, &flags);
1003     p->flags = flags;
1004     if (res)
1005         return res;
1006     if (vb2_queue_is_busy(vdev->queue, file))
1007         return -EBUSY;
1008     res = vb2_core_reqbufs(vdev->queue, p->memory, p->flags, &p->count);
1009     /* If count == 0, then the owner has released all buffers and he
1010        is no longer owner of the queue. Otherwise we have a new owner. */
1011     if (res == 0)
1012         vdev->queue->owner = p->count ? file->private_data : NULL;
1013     return res;
1014 }
1015 EXPORT_SYMBOL_GPL(vb2_ioctl_reqbufs);
1016 
1017 int vb2_ioctl_create_bufs(struct file *file, void *priv,
1018               struct v4l2_create_buffers *p)
1019 {
1020     struct video_device *vdev = video_devdata(file);
1021     int res = vb2_verify_memory_type(vdev->queue, p->memory,
1022             p->format.type);
1023 
1024     p->index = vdev->queue->num_buffers;
1025     fill_buf_caps(vdev->queue, &p->capabilities);
1026     validate_memory_flags(vdev->queue, p->memory, &p->flags);
1027     /*
1028      * If count == 0, then just check if memory and type are valid.
1029      * Any -EBUSY result from vb2_verify_memory_type can be mapped to 0.
1030      */
1031     if (p->count == 0)
1032         return res != -EBUSY ? res : 0;
1033     if (res)
1034         return res;
1035     if (vb2_queue_is_busy(vdev->queue, file))
1036         return -EBUSY;
1037 
1038     res = vb2_create_bufs(vdev->queue, p);
1039     if (res == 0)
1040         vdev->queue->owner = file->private_data;
1041     return res;
1042 }
1043 EXPORT_SYMBOL_GPL(vb2_ioctl_create_bufs);
1044 
1045 int vb2_ioctl_prepare_buf(struct file *file, void *priv,
1046               struct v4l2_buffer *p)
1047 {
1048     struct video_device *vdev = video_devdata(file);
1049 
1050     if (vb2_queue_is_busy(vdev->queue, file))
1051         return -EBUSY;
1052     return vb2_prepare_buf(vdev->queue, vdev->v4l2_dev->mdev, p);
1053 }
1054 EXPORT_SYMBOL_GPL(vb2_ioctl_prepare_buf);
1055 
1056 int vb2_ioctl_querybuf(struct file *file, void *priv, struct v4l2_buffer *p)
1057 {
1058     struct video_device *vdev = video_devdata(file);
1059 
1060     /* No need to call vb2_queue_is_busy(), anyone can query buffers. */
1061     return vb2_querybuf(vdev->queue, p);
1062 }
1063 EXPORT_SYMBOL_GPL(vb2_ioctl_querybuf);
1064 
1065 int vb2_ioctl_qbuf(struct file *file, void *priv, struct v4l2_buffer *p)
1066 {
1067     struct video_device *vdev = video_devdata(file);
1068 
1069     if (vb2_queue_is_busy(vdev->queue, file))
1070         return -EBUSY;
1071     return vb2_qbuf(vdev->queue, vdev->v4l2_dev->mdev, p);
1072 }
1073 EXPORT_SYMBOL_GPL(vb2_ioctl_qbuf);
1074 
1075 int vb2_ioctl_dqbuf(struct file *file, void *priv, struct v4l2_buffer *p)
1076 {
1077     struct video_device *vdev = video_devdata(file);
1078 
1079     if (vb2_queue_is_busy(vdev->queue, file))
1080         return -EBUSY;
1081     return vb2_dqbuf(vdev->queue, p, file->f_flags & O_NONBLOCK);
1082 }
1083 EXPORT_SYMBOL_GPL(vb2_ioctl_dqbuf);
1084 
1085 int vb2_ioctl_streamon(struct file *file, void *priv, enum v4l2_buf_type i)
1086 {
1087     struct video_device *vdev = video_devdata(file);
1088 
1089     if (vb2_queue_is_busy(vdev->queue, file))
1090         return -EBUSY;
1091     return vb2_streamon(vdev->queue, i);
1092 }
1093 EXPORT_SYMBOL_GPL(vb2_ioctl_streamon);
1094 
1095 int vb2_ioctl_streamoff(struct file *file, void *priv, enum v4l2_buf_type i)
1096 {
1097     struct video_device *vdev = video_devdata(file);
1098 
1099     if (vb2_queue_is_busy(vdev->queue, file))
1100         return -EBUSY;
1101     return vb2_streamoff(vdev->queue, i);
1102 }
1103 EXPORT_SYMBOL_GPL(vb2_ioctl_streamoff);
1104 
1105 int vb2_ioctl_expbuf(struct file *file, void *priv, struct v4l2_exportbuffer *p)
1106 {
1107     struct video_device *vdev = video_devdata(file);
1108 
1109     if (vb2_queue_is_busy(vdev->queue, file))
1110         return -EBUSY;
1111     return vb2_expbuf(vdev->queue, p);
1112 }
1113 EXPORT_SYMBOL_GPL(vb2_ioctl_expbuf);
1114 
1115 /* v4l2_file_operations helpers */
1116 
1117 int vb2_fop_mmap(struct file *file, struct vm_area_struct *vma)
1118 {
1119     struct video_device *vdev = video_devdata(file);
1120 
1121     return vb2_mmap(vdev->queue, vma);
1122 }
1123 EXPORT_SYMBOL_GPL(vb2_fop_mmap);
1124 
1125 int _vb2_fop_release(struct file *file, struct mutex *lock)
1126 {
1127     struct video_device *vdev = video_devdata(file);
1128 
1129     if (lock)
1130         mutex_lock(lock);
1131     if (file->private_data == vdev->queue->owner) {
1132         vb2_queue_release(vdev->queue);
1133         vdev->queue->owner = NULL;
1134     }
1135     if (lock)
1136         mutex_unlock(lock);
1137     return v4l2_fh_release(file);
1138 }
1139 EXPORT_SYMBOL_GPL(_vb2_fop_release);
1140 
1141 int vb2_fop_release(struct file *file)
1142 {
1143     struct video_device *vdev = video_devdata(file);
1144     struct mutex *lock = vdev->queue->lock ? vdev->queue->lock : vdev->lock;
1145 
1146     return _vb2_fop_release(file, lock);
1147 }
1148 EXPORT_SYMBOL_GPL(vb2_fop_release);
1149 
1150 ssize_t vb2_fop_write(struct file *file, const char __user *buf,
1151         size_t count, loff_t *ppos)
1152 {
1153     struct video_device *vdev = video_devdata(file);
1154     struct mutex *lock = vdev->queue->lock ? vdev->queue->lock : vdev->lock;
1155     int err = -EBUSY;
1156 
1157     if (!(vdev->queue->io_modes & VB2_WRITE))
1158         return -EINVAL;
1159     if (lock && mutex_lock_interruptible(lock))
1160         return -ERESTARTSYS;
1161     if (vb2_queue_is_busy(vdev->queue, file))
1162         goto exit;
1163     err = vb2_write(vdev->queue, buf, count, ppos,
1164                file->f_flags & O_NONBLOCK);
1165     if (vdev->queue->fileio)
1166         vdev->queue->owner = file->private_data;
1167 exit:
1168     if (lock)
1169         mutex_unlock(lock);
1170     return err;
1171 }
1172 EXPORT_SYMBOL_GPL(vb2_fop_write);
1173 
1174 ssize_t vb2_fop_read(struct file *file, char __user *buf,
1175         size_t count, loff_t *ppos)
1176 {
1177     struct video_device *vdev = video_devdata(file);
1178     struct mutex *lock = vdev->queue->lock ? vdev->queue->lock : vdev->lock;
1179     int err = -EBUSY;
1180 
1181     if (!(vdev->queue->io_modes & VB2_READ))
1182         return -EINVAL;
1183     if (lock && mutex_lock_interruptible(lock))
1184         return -ERESTARTSYS;
1185     if (vb2_queue_is_busy(vdev->queue, file))
1186         goto exit;
1187     err = vb2_read(vdev->queue, buf, count, ppos,
1188                file->f_flags & O_NONBLOCK);
1189     if (vdev->queue->fileio)
1190         vdev->queue->owner = file->private_data;
1191 exit:
1192     if (lock)
1193         mutex_unlock(lock);
1194     return err;
1195 }
1196 EXPORT_SYMBOL_GPL(vb2_fop_read);
1197 
1198 __poll_t vb2_fop_poll(struct file *file, poll_table *wait)
1199 {
1200     struct video_device *vdev = video_devdata(file);
1201     struct vb2_queue *q = vdev->queue;
1202     struct mutex *lock = q->lock ? q->lock : vdev->lock;
1203     __poll_t res;
1204     void *fileio;
1205 
1206     /*
1207      * If this helper doesn't know how to lock, then you shouldn't be using
1208      * it but you should write your own.
1209      */
1210     WARN_ON(!lock);
1211 
1212     if (lock && mutex_lock_interruptible(lock))
1213         return EPOLLERR;
1214 
1215     fileio = q->fileio;
1216 
1217     res = vb2_poll(vdev->queue, file, wait);
1218 
1219     /* If fileio was started, then we have a new queue owner. */
1220     if (!fileio && q->fileio)
1221         q->owner = file->private_data;
1222     if (lock)
1223         mutex_unlock(lock);
1224     return res;
1225 }
1226 EXPORT_SYMBOL_GPL(vb2_fop_poll);
1227 
1228 #ifndef CONFIG_MMU
1229 unsigned long vb2_fop_get_unmapped_area(struct file *file, unsigned long addr,
1230         unsigned long len, unsigned long pgoff, unsigned long flags)
1231 {
1232     struct video_device *vdev = video_devdata(file);
1233 
1234     return vb2_get_unmapped_area(vdev->queue, addr, len, pgoff, flags);
1235 }
1236 EXPORT_SYMBOL_GPL(vb2_fop_get_unmapped_area);
1237 #endif
1238 
1239 void vb2_video_unregister_device(struct video_device *vdev)
1240 {
1241     /* Check if vdev was ever registered at all */
1242     if (!vdev || !video_is_registered(vdev))
1243         return;
1244 
1245     /*
1246      * Calling this function only makes sense if vdev->queue is set.
1247      * If it is NULL, then just call video_unregister_device() instead.
1248      */
1249     WARN_ON(!vdev->queue);
1250 
1251     /*
1252      * Take a reference to the device since video_unregister_device()
1253      * calls device_unregister(), but we don't want that to release
1254      * the device since we want to clean up the queue first.
1255      */
1256     get_device(&vdev->dev);
1257     video_unregister_device(vdev);
1258     if (vdev->queue && vdev->queue->owner) {
1259         struct mutex *lock = vdev->queue->lock ?
1260             vdev->queue->lock : vdev->lock;
1261 
1262         if (lock)
1263             mutex_lock(lock);
1264         vb2_queue_release(vdev->queue);
1265         vdev->queue->owner = NULL;
1266         if (lock)
1267             mutex_unlock(lock);
1268     }
1269     /*
1270      * Now we put the device, and in most cases this will release
1271      * everything.
1272      */
1273     put_device(&vdev->dev);
1274 }
1275 EXPORT_SYMBOL_GPL(vb2_video_unregister_device);
1276 
1277 /* vb2_ops helpers. Only use if vq->lock is non-NULL. */
1278 
1279 void vb2_ops_wait_prepare(struct vb2_queue *vq)
1280 {
1281     mutex_unlock(vq->lock);
1282 }
1283 EXPORT_SYMBOL_GPL(vb2_ops_wait_prepare);
1284 
1285 void vb2_ops_wait_finish(struct vb2_queue *vq)
1286 {
1287     mutex_lock(vq->lock);
1288 }
1289 EXPORT_SYMBOL_GPL(vb2_ops_wait_finish);
1290 
1291 /*
1292  * Note that this function is called during validation time and
1293  * thus the req_queue_mutex is held to ensure no request objects
1294  * can be added or deleted while validating. So there is no need
1295  * to protect the objects list.
1296  */
1297 int vb2_request_validate(struct media_request *req)
1298 {
1299     struct media_request_object *obj;
1300     int ret = 0;
1301 
1302     if (!vb2_request_buffer_cnt(req))
1303         return -ENOENT;
1304 
1305     list_for_each_entry(obj, &req->objects, list) {
1306         if (!obj->ops->prepare)
1307             continue;
1308 
1309         ret = obj->ops->prepare(obj);
1310         if (ret)
1311             break;
1312     }
1313 
1314     if (ret) {
1315         list_for_each_entry_continue_reverse(obj, &req->objects, list)
1316             if (obj->ops->unprepare)
1317                 obj->ops->unprepare(obj);
1318         return ret;
1319     }
1320     return 0;
1321 }
1322 EXPORT_SYMBOL_GPL(vb2_request_validate);
1323 
1324 void vb2_request_queue(struct media_request *req)
1325 {
1326     struct media_request_object *obj, *obj_safe;
1327 
1328     /*
1329      * Queue all objects. Note that buffer objects are at the end of the
1330      * objects list, after all other object types. Once buffer objects
1331      * are queued, the driver might delete them immediately (if the driver
1332      * processes the buffer at once), so we have to use
1333      * list_for_each_entry_safe() to handle the case where the object we
1334      * queue is deleted.
1335      */
1336     list_for_each_entry_safe(obj, obj_safe, &req->objects, list)
1337         if (obj->ops->queue)
1338             obj->ops->queue(obj);
1339 }
1340 EXPORT_SYMBOL_GPL(vb2_request_queue);
1341 
1342 MODULE_DESCRIPTION("Driver helper framework for Video for Linux 2");
1343 MODULE_AUTHOR("Pawel Osciak <pawel@osciak.com>, Marek Szyprowski");
1344 MODULE_LICENSE("GPL");
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