/* * videobuf2-core.c - V4L2 driver helper framework * * Copyright (C) 2010 Samsung Electronics * * Author: Pawel Osciak * Marek Szyprowski * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation. */ #include #include #include #include #include #include #include #include #include #include #include static int debug; module_param(debug, int, 0644); #define dprintk(level, fmt, arg...) \ do { \ if (debug >= level) \ printk(KERN_DEBUG "vb2: " fmt, ## arg); \ } while (0) #define call_memop(q, op, args...) \ (((q)->mem_ops->op) ? \ ((q)->mem_ops->op(args)) : 0) #define call_qop(q, op, args...) \ (((q)->ops->op) ? ((q)->ops->op(args)) : 0) #define V4L2_BUFFER_MASK_FLAGS (V4L2_BUF_FLAG_MAPPED | V4L2_BUF_FLAG_QUEUED | \ V4L2_BUF_FLAG_DONE | V4L2_BUF_FLAG_ERROR | \ V4L2_BUF_FLAG_PREPARED | \ V4L2_BUF_FLAG_TIMESTAMP_MASK) /** * __vb2_buf_mem_alloc() - allocate video memory for the given buffer */ static int __vb2_buf_mem_alloc(struct vb2_buffer *vb) { struct vb2_queue *q = vb->vb2_queue; void *mem_priv; int plane; /* * Allocate memory for all planes in this buffer * NOTE: mmapped areas should be page aligned */ for (plane = 0; plane < vb->num_planes; ++plane) { unsigned long size = PAGE_ALIGN(q->plane_sizes[plane]); mem_priv = call_memop(q, alloc, q->alloc_ctx[plane], size, q->gfp_flags); if (IS_ERR_OR_NULL(mem_priv)) goto free; /* Associate allocator private data with this plane */ vb->planes[plane].mem_priv = mem_priv; vb->v4l2_planes[plane].length = q->plane_sizes[plane]; } return 0; free: /* Free already allocated memory if one of the allocations failed */ for (; plane > 0; --plane) { call_memop(q, put, vb->planes[plane - 1].mem_priv); vb->planes[plane - 1].mem_priv = NULL; } return -ENOMEM; } /** * __vb2_buf_mem_free() - free memory of the given buffer */ static void __vb2_buf_mem_free(struct vb2_buffer *vb) { struct vb2_queue *q = vb->vb2_queue; unsigned int plane; for (plane = 0; plane < vb->num_planes; ++plane) { call_memop(q, put, vb->planes[plane].mem_priv); vb->planes[plane].mem_priv = NULL; dprintk(3, "Freed plane %d of buffer %d\n", plane, vb->v4l2_buf.index); } } /** * __vb2_buf_userptr_put() - release userspace memory associated with * a USERPTR buffer */ static void __vb2_buf_userptr_put(struct vb2_buffer *vb) { struct vb2_queue *q = vb->vb2_queue; unsigned int plane; for (plane = 0; plane < vb->num_planes; ++plane) { if (vb->planes[plane].mem_priv) call_memop(q, put_userptr, vb->planes[plane].mem_priv); vb->planes[plane].mem_priv = NULL; } } /** * __vb2_plane_dmabuf_put() - release memory associated with * a DMABUF shared plane */ static void __vb2_plane_dmabuf_put(struct vb2_queue *q, struct vb2_plane *p) { if (!p->mem_priv) return; if (p->dbuf_mapped) call_memop(q, unmap_dmabuf, p->mem_priv); call_memop(q, detach_dmabuf, p->mem_priv); dma_buf_put(p->dbuf); memset(p, 0, sizeof(*p)); } /** * __vb2_buf_dmabuf_put() - release memory associated with * a DMABUF shared buffer */ static void __vb2_buf_dmabuf_put(struct vb2_buffer *vb) { struct vb2_queue *q = vb->vb2_queue; unsigned int plane; for (plane = 0; plane < vb->num_planes; ++plane) __vb2_plane_dmabuf_put(q, &vb->planes[plane]); } /** * __setup_offsets() - setup unique offsets ("cookies") for every plane in * every buffer on the queue */ static void __setup_offsets(struct vb2_queue *q, unsigned int n) { unsigned int buffer, plane; struct vb2_buffer *vb; unsigned long off; if (q->num_buffers) { struct v4l2_plane *p; vb = q->bufs[q->num_buffers - 1]; p = &vb->v4l2_planes[vb->num_planes - 1]; off = PAGE_ALIGN(p->m.mem_offset + p->length); } else { off = 0; } for (buffer = q->num_buffers; buffer < q->num_buffers + n; ++buffer) { vb = q->bufs[buffer]; if (!vb) continue; for (plane = 0; plane < vb->num_planes; ++plane) { vb->v4l2_planes[plane].length = q->plane_sizes[plane]; vb->v4l2_planes[plane].m.mem_offset = off; dprintk(3, "Buffer %d, plane %d offset 0x%08lx\n", buffer, plane, off); off += vb->v4l2_planes[plane].length; off = PAGE_ALIGN(off); } } } /** * __vb2_queue_alloc() - allocate videobuf buffer structures and (for MMAP type) * video buffer memory for all buffers/planes on the queue and initializes the * queue * * Returns the number of buffers successfully allocated. */ static int __vb2_queue_alloc(struct vb2_queue *q, enum v4l2_memory memory, unsigned int num_buffers, unsigned int num_planes) { unsigned int buffer; struct vb2_buffer *vb; int ret; for (buffer = 0; buffer < num_buffers; ++buffer) { /* Allocate videobuf buffer structures */ vb = kzalloc(q->buf_struct_size, GFP_KERNEL); if (!vb) { dprintk(1, "Memory alloc for buffer struct failed\n"); break; } /* Length stores number of planes for multiplanar buffers */ if (V4L2_TYPE_IS_MULTIPLANAR(q->type)) vb->v4l2_buf.length = num_planes; vb->state = VB2_BUF_STATE_DEQUEUED; vb->vb2_queue = q; vb->num_planes = num_planes; vb->v4l2_buf.index = q->num_buffers + buffer; vb->v4l2_buf.type = q->type; vb->v4l2_buf.memory = memory; /* Allocate video buffer memory for the MMAP type */ if (memory == V4L2_MEMORY_MMAP) { ret = __vb2_buf_mem_alloc(vb); if (ret) { dprintk(1, "Failed allocating memory for " "buffer %d\n", buffer); kfree(vb); break; } /* * Call the driver-provided buffer initialization * callback, if given. An error in initialization * results in queue setup failure. */ ret = call_qop(q, buf_init, vb); if (ret) { dprintk(1, "Buffer %d %p initialization" " failed\n", buffer, vb); __vb2_buf_mem_free(vb); kfree(vb); break; } } q->bufs[q->num_buffers + buffer] = vb; } __setup_offsets(q, buffer); dprintk(1, "Allocated %d buffers, %d plane(s) each\n", buffer, num_planes); return buffer; } /** * __vb2_free_mem() - release all video buffer memory for a given queue */ static void __vb2_free_mem(struct vb2_queue *q, unsigned int buffers) { unsigned int buffer; struct vb2_buffer *vb; for (buffer = q->num_buffers - buffers; buffer < q->num_buffers; ++buffer) { vb = q->bufs[buffer]; if (!vb) continue; /* Free MMAP buffers or release USERPTR buffers */ if (q->memory == V4L2_MEMORY_MMAP) __vb2_buf_mem_free(vb); else if (q->memory == V4L2_MEMORY_DMABUF) __vb2_buf_dmabuf_put(vb); else __vb2_buf_userptr_put(vb); } } /** * __vb2_queue_free() - free buffers at the end of the queue - video memory and * related information, if no buffers are left return the queue to an * uninitialized state. Might be called even if the queue has already been freed. */ static void __vb2_queue_free(struct vb2_queue *q, unsigned int buffers) { unsigned int buffer; /* Call driver-provided cleanup function for each buffer, if provided */ if (q->ops->buf_cleanup) { for (buffer = q->num_buffers - buffers; buffer < q->num_buffers; ++buffer) { if (NULL == q->bufs[buffer]) continue; q->ops->buf_cleanup(q->bufs[buffer]); } } /* Release video buffer memory */ __vb2_free_mem(q, buffers); /* Free videobuf buffers */ for (buffer = q->num_buffers - buffers; buffer < q->num_buffers; ++buffer) { kfree(q->bufs[buffer]); q->bufs[buffer] = NULL; } q->num_buffers -= buffers; if (!q->num_buffers) q->memory = 0; INIT_LIST_HEAD(&q->queued_list); } /** * __verify_planes_array() - verify that the planes array passed in struct * v4l2_buffer from userspace can be safely used */ static int __verify_planes_array(struct vb2_buffer *vb, const struct v4l2_buffer *b) { if (!V4L2_TYPE_IS_MULTIPLANAR(b->type)) return 0; /* Is memory for copying plane information present? */ if (NULL == b->m.planes) { dprintk(1, "Multi-planar buffer passed but " "planes array not provided\n"); return -EINVAL; } if (b->length < vb->num_planes || b->length > VIDEO_MAX_PLANES) { dprintk(1, "Incorrect planes array length, " "expected %d, got %d\n", vb->num_planes, b->length); return -EINVAL; } return 0; } /** * __buffer_in_use() - return true if the buffer is in use and * the queue cannot be freed (by the means of REQBUFS(0)) call */ static bool __buffer_in_use(struct vb2_queue *q, struct vb2_buffer *vb) { unsigned int plane; for (plane = 0; plane < vb->num_planes; ++plane) { void *mem_priv = vb->planes[plane].mem_priv; /* * If num_users() has not been provided, call_memop * will return 0, apparently nobody cares about this * case anyway. If num_users() returns more than 1, * we are not the only user of the plane's memory. */ if (mem_priv && call_memop(q, num_users, mem_priv) > 1) return true; } return false; } /** * __buffers_in_use() - return true if any buffers on the queue are in use and * the queue cannot be freed (by the means of REQBUFS(0)) call */ static bool __buffers_in_use(struct vb2_queue *q) { unsigned int buffer; for (buffer = 0; buffer < q->num_buffers; ++buffer) { if (__buffer_in_use(q, q->bufs[buffer])) return true; } return false; } /** * __fill_v4l2_buffer() - fill in a struct v4l2_buffer with information to be * returned to userspace */ static void __fill_v4l2_buffer(struct vb2_buffer *vb, struct v4l2_buffer *b) { struct vb2_queue *q = vb->vb2_queue; /* Copy back data such as timestamp, flags, etc. */ memcpy(b, &vb->v4l2_buf, offsetof(struct v4l2_buffer, m)); b->reserved2 = vb->v4l2_buf.reserved2; b->reserved = vb->v4l2_buf.reserved; if (V4L2_TYPE_IS_MULTIPLANAR(q->type)) { /* * Fill in plane-related data if userspace provided an array * for it. The caller has already verified memory and size. */ b->length = vb->num_planes; memcpy(b->m.planes, vb->v4l2_planes, b->length * sizeof(struct v4l2_plane)); } else { /* * We use length and offset in v4l2_planes array even for * single-planar buffers, but userspace does not. */ b->length = vb->v4l2_planes[0].length; b->bytesused = vb->v4l2_planes[0].bytesused; if (q->memory == V4L2_MEMORY_MMAP) b->m.offset = vb->v4l2_planes[0].m.mem_offset; else if (q->memory == V4L2_MEMORY_USERPTR) b->m.userptr = vb->v4l2_planes[0].m.userptr; else if (q->memory == V4L2_MEMORY_DMABUF) b->m.fd = vb->v4l2_planes[0].m.fd; } /* * Clear any buffer state related flags. */ b->flags &= ~V4L2_BUFFER_MASK_FLAGS; b->flags |= q->timestamp_type; switch (vb->state) { case VB2_BUF_STATE_QUEUED: case VB2_BUF_STATE_ACTIVE: b->flags |= V4L2_BUF_FLAG_QUEUED; break; case VB2_BUF_STATE_ERROR: b->flags |= V4L2_BUF_FLAG_ERROR; /* fall through */ case VB2_BUF_STATE_DONE: b->flags |= V4L2_BUF_FLAG_DONE; break; case VB2_BUF_STATE_PREPARED: b->flags |= V4L2_BUF_FLAG_PREPARED; break; case VB2_BUF_STATE_DEQUEUED: /* nothing */ break; } if (__buffer_in_use(q, vb)) b->flags |= V4L2_BUF_FLAG_MAPPED; } /** * vb2_querybuf() - query video buffer information * @q: videobuf queue * @b: buffer struct passed from userspace to vidioc_querybuf handler * in driver * * Should be called from vidioc_querybuf ioctl handler in driver. * This function will verify the passed v4l2_buffer structure and fill the * relevant information for the userspace. * * The return values from this function are intended to be directly returned * from vidioc_querybuf handler in driver. */ int vb2_querybuf(struct vb2_queue *q, struct v4l2_buffer *b) { struct vb2_buffer *vb; int ret; if (b->type != q->type) { dprintk(1, "querybuf: wrong buffer type\n"); return -EINVAL; } if (b->index >= q->num_buffers) { dprintk(1, "querybuf: buffer index out of range\n"); return -EINVAL; } vb = q->bufs[b->index]; ret = __verify_planes_array(vb, b); if (!ret) __fill_v4l2_buffer(vb, b); return ret; } EXPORT_SYMBOL(vb2_querybuf); /** * __verify_userptr_ops() - verify that all memory operations required for * USERPTR queue type have been provided */ static int __verify_userptr_ops(struct vb2_queue *q) { if (!(q->io_modes & VB2_USERPTR) || !q->mem_ops->get_userptr || !q->mem_ops->put_userptr) return -EINVAL; return 0; } /** * __verify_mmap_ops() - verify that all memory operations required for * MMAP queue type have been provided */ static int __verify_mmap_ops(struct vb2_queue *q) { if (!(q->io_modes & VB2_MMAP) || !q->mem_ops->alloc || !q->mem_ops->put || !q->mem_ops->mmap) return -EINVAL; return 0; } /** * __verify_dmabuf_ops() - verify that all memory operations required for * DMABUF queue type have been provided */ static int __verify_dmabuf_ops(struct vb2_queue *q) { if (!(q->io_modes & VB2_DMABUF) || !q->mem_ops->attach_dmabuf || !q->mem_ops->detach_dmabuf || !q->mem_ops->map_dmabuf || !q->mem_ops->unmap_dmabuf) return -EINVAL; return 0; } /** * __verify_memory_type() - Check whether the memory type and buffer type * passed to a buffer operation are compatible with the queue. */ static int __verify_memory_type(struct vb2_queue *q, enum v4l2_memory memory, enum v4l2_buf_type type) { if (memory != V4L2_MEMORY_MMAP && memory != V4L2_MEMORY_USERPTR && memory != V4L2_MEMORY_DMABUF) { dprintk(1, "reqbufs: unsupported memory type\n"); return -EINVAL; } if (type != q->type) { dprintk(1, "reqbufs: requested type is incorrect\n"); return -EINVAL; } /* * Make sure all the required memory ops for given memory type * are available. */ if (memory == V4L2_MEMORY_MMAP && __verify_mmap_ops(q)) { dprintk(1, "reqbufs: MMAP for current setup unsupported\n"); return -EINVAL; } if (memory == V4L2_MEMORY_USERPTR && __verify_userptr_ops(q)) { dprintk(1, "reqbufs: USERPTR for current setup unsupported\n"); return -EINVAL; } if (memory == V4L2_MEMORY_DMABUF && __verify_dmabuf_ops(q)) { dprintk(1, "reqbufs: DMABUF for current setup unsupported\n"); return -EINVAL; } /* * Place the busy tests at the end: -EBUSY can be ignored when * create_bufs is called with count == 0, but count == 0 should still * do the memory and type validation. */ if (q->fileio) { dprintk(1, "reqbufs: file io in progress\n"); return -EBUSY; } return 0; } /** * __reqbufs() - Initiate streaming * @q: videobuf2 queue * @req: struct passed from userspace to vidioc_reqbufs handler in driver * * Should be called from vidioc_reqbufs ioctl handler of a driver. * This function: * 1) verifies streaming parameters passed from the userspace, * 2) sets up the queue, * 3) negotiates number of buffers and planes per buffer with the driver * to be used during streaming, * 4) allocates internal buffer structures (struct vb2_buffer), according to * the agreed parameters, * 5) for MMAP memory type, allocates actual video memory, using the * memory handling/allocation routines provided during queue initialization * * If req->count is 0, all the memory will be freed instead. * If the queue has been allocated previously (by a previous vb2_reqbufs) call * and the queue is not busy, memory will be reallocated. * * The return values from this function are intended to be directly returned * from vidioc_reqbufs handler in driver. */ static int __reqbufs(struct vb2_queue *q, struct v4l2_requestbuffers *req) { unsigned int num_buffers, allocated_buffers, num_planes = 0; int ret; if (q->streaming) { dprintk(1, "reqbufs: streaming active\n"); return -EBUSY; } if (req->count == 0 || q->num_buffers != 0 || q->memory != req->memory) { /* * We already have buffers allocated, so first check if they * are not in use and can be freed. */ if (q->memory == V4L2_MEMORY_MMAP && __buffers_in_use(q)) { dprintk(1, "reqbufs: memory in use, cannot free\n"); return -EBUSY; } __vb2_queue_free(q, q->num_buffers); /* * In case of REQBUFS(0) return immediately without calling * driver's queue_setup() callback and allocating resources. */ if (req->count == 0) return 0; } /* * Make sure the requested values and current defaults are sane. */ num_buffers = min_t(unsigned int, req->count, VIDEO_MAX_FRAME); memset(q->plane_sizes, 0, sizeof(q->plane_sizes)); memset(q->alloc_ctx, 0, sizeof(q->alloc_ctx)); q->memory = req->memory; /* * Ask the driver how many buffers and planes per buffer it requires. * Driver also sets the size and allocator context for each plane. */ ret = call_qop(q, queue_setup, q, NULL, &num_buffers, &num_planes, q->plane_sizes, q->alloc_ctx); if (ret) return ret; /* Finally, allocate buffers and video memory */ ret = __vb2_queue_alloc(q, req->memory, num_buffers, num_planes); if (ret == 0) { dprintk(1, "Memory allocation failed\n"); return -ENOMEM; } allocated_buffers = ret; /* * Check if driver can handle the allocated number of buffers. */ if (allocated_buffers < num_buffers) { num_buffers = allocated_buffers; ret = call_qop(q, queue_setup, q, NULL, &num_buffers, &num_planes, q->plane_sizes, q->alloc_ctx); if (!ret && allocated_buffers < num_buffers) ret = -ENOMEM; /* * Either the driver has accepted a smaller number of buffers, * or .queue_setup() returned an error */ } q->num_buffers = allocated_buffers; if (ret < 0) { __vb2_queue_free(q, allocated_buffers); return ret; } /* * Return the number of successfully allocated buffers * to the userspace. */ req->count = allocated_buffers; return 0; } /** * vb2_reqbufs() - Wrapper for __reqbufs() that also verifies the memory and * type values. * @q: videobuf2 queue * @req: struct passed from userspace to vidioc_reqbufs handler in driver */ int vb2_reqbufs(struct vb2_queue *q, struct v4l2_requestbuffers *req) { int ret = __verify_memory_type(q, req->memory, req->type); return ret ? ret : __reqbufs(q, req); } EXPORT_SYMBOL_GPL(vb2_reqbufs); /** * __create_bufs() - Allocate buffers and any required auxiliary structs * @q: videobuf2 queue * @create: creation parameters, passed from userspace to vidioc_create_bufs * handler in driver * * Should be called from vidioc_create_bufs ioctl handler of a driver. * This function: * 1) verifies parameter sanity * 2) calls the .queue_setup() queue operation * 3) performs any necessary memory allocations * * The return values from this function are intended to be directly returned * from vidioc_create_bufs handler in driver. */ static int __create_bufs(struct vb2_queue *q, struct v4l2_create_buffers *create) { unsigned int num_planes = 0, num_buffers, allocated_buffers; int ret; if (q->num_buffers == VIDEO_MAX_FRAME) { dprintk(1, "%s(): maximum number of buffers already allocated\n", __func__); return -ENOBUFS; } if (!q->num_buffers) { memset(q->plane_sizes, 0, sizeof(q->plane_sizes)); memset(q->alloc_ctx, 0, sizeof(q->alloc_ctx)); q->memory = create->memory; } num_buffers = min(create->count, VIDEO_MAX_FRAME - q->num_buffers); /* * Ask the driver, whether the requested number of buffers, planes per * buffer and their sizes are acceptable */ ret = call_qop(q, queue_setup, q, &create->format, &num_buffers, &num_planes, q->plane_sizes, q->alloc_ctx); if (ret) return ret; /* Finally, allocate buffers and video memory */ ret = __vb2_queue_alloc(q, create->memory, num_buffers, num_planes); if (ret == 0) { dprintk(1, "Memory allocation failed\n"); return -ENOMEM; } allocated_buffers = ret; /* * Check if driver can handle the so far allocated number of buffers. */ if (ret < num_buffers) { num_buffers = ret; /* * q->num_buffers contains the total number of buffers, that the * queue driver has set up */ ret = call_qop(q, queue_setup, q, &create->format, &num_buffers, &num_planes, q->plane_sizes, q->alloc_ctx); if (!ret && allocated_buffers < num_buffers) ret = -ENOMEM; /* * Either the driver has accepted a smaller number of buffers, * or .queue_setup() returned an error */ } q->num_buffers += allocated_buffers; if (ret < 0) { __vb2_queue_free(q, allocated_buffers); return -ENOMEM; } /* * Return the number of successfully allocated buffers * to the userspace. */ create->count = allocated_buffers; return 0; } /** * vb2_create_bufs() - Wrapper for __create_bufs() that also verifies the * memory and type values. * @q: videobuf2 queue * @create: creation parameters, passed from userspace to vidioc_create_bufs * handler in driver */ int vb2_create_bufs(struct vb2_queue *q, struct v4l2_create_buffers *create) { int ret = __verify_memory_type(q, create->memory, create->format.type); create->index = q->num_buffers; if (create->count == 0) return ret != -EBUSY ? ret : 0; return ret ? ret : __create_bufs(q, create); } EXPORT_SYMBOL_GPL(vb2_create_bufs); /** * vb2_plane_vaddr() - Return a kernel virtual address of a given plane * @vb: vb2_buffer to which the plane in question belongs to * @plane_no: plane number for which the address is to be returned * * This function returns a kernel virtual address of a given plane if * such a mapping exist, NULL otherwise. */ void *vb2_plane_vaddr(struct vb2_buffer *vb, unsigned int plane_no) { struct vb2_queue *q = vb->vb2_queue; if (plane_no > vb->num_planes || !vb->planes[plane_no].mem_priv) return NULL; return call_memop(q, vaddr, vb->planes[plane_no].mem_priv); } EXPORT_SYMBOL_GPL(vb2_plane_vaddr); /** * vb2_plane_cookie() - Return allocator specific cookie for the given plane * @vb: vb2_buffer to which the plane in question belongs to * @plane_no: plane number for which the cookie is to be returned * * This function returns an allocator specific cookie for a given plane if * available, NULL otherwise. The allocator should provide some simple static * inline function, which would convert this cookie to the allocator specific * type that can be used directly by the driver to access the buffer. This can * be for example physical address, pointer to scatter list or IOMMU mapping. */ void *vb2_plane_cookie(struct vb2_buffer *vb, unsigned int plane_no) { struct vb2_queue *q = vb->vb2_queue; if (plane_no > vb->num_planes || !vb->planes[plane_no].mem_priv) return NULL; return call_memop(q, cookie, vb->planes[plane_no].mem_priv); } EXPORT_SYMBOL_GPL(vb2_plane_cookie); /** * vb2_buffer_done() - inform videobuf that an operation on a buffer is finished * @vb: vb2_buffer returned from the driver * @state: either VB2_BUF_STATE_DONE if the operation finished successfully * or VB2_BUF_STATE_ERROR if the operation finished with an error * * This function should be called by the driver after a hardware operation on * a buffer is finished and the buffer may be returned to userspace. The driver * cannot use this buffer anymore until it is queued back to it by videobuf * by the means of buf_queue callback. Only buffers previously queued to the * driver by buf_queue can be passed to this function. */ void vb2_buffer_done(struct vb2_buffer *vb, enum vb2_buffer_state state) { struct vb2_queue *q = vb->vb2_queue; unsigned long flags; unsigned int plane; if (vb->state != VB2_BUF_STATE_ACTIVE) return; if (state != VB2_BUF_STATE_DONE && state != VB2_BUF_STATE_ERROR) return; dprintk(4, "Done processing on buffer %d, state: %d\n", vb->v4l2_buf.index, state); /* sync buffers */ for (plane = 0; plane < vb->num_planes; ++plane) call_memop(q, finish, vb->planes[plane].mem_priv); /* Add the buffer to the done buffers list */ spin_lock_irqsave(&q->done_lock, flags); vb->state = state; list_add_tail(&vb->done_entry, &q->done_list); atomic_dec(&q->queued_count); spin_unlock_irqrestore(&q->done_lock, flags); /* Inform any processes that may be waiting for buffers */ wake_up(&q->done_wq); } EXPORT_SYMBOL_GPL(vb2_buffer_done); /** * __fill_vb2_buffer() - fill a vb2_buffer with information provided in a * v4l2_buffer by the userspace. The caller has already verified that struct * v4l2_buffer has a valid number of planes. */ static void __fill_vb2_buffer(struct vb2_buffer *vb, const struct v4l2_buffer *b, struct v4l2_plane *v4l2_planes) { unsigned int plane; if (V4L2_TYPE_IS_MULTIPLANAR(b->type)) { /* Fill in driver-provided information for OUTPUT types */ if (V4L2_TYPE_IS_OUTPUT(b->type)) { /* * Will have to go up to b->length when API starts * accepting variable number of planes. */ for (plane = 0; plane < vb->num_planes; ++plane) { v4l2_planes[plane].bytesused = b->m.planes[plane].bytesused; v4l2_planes[plane].data_offset = b->m.planes[plane].data_offset; } } if (b->memory == V4L2_MEMORY_USERPTR) { for (plane = 0; plane < vb->num_planes; ++plane) { v4l2_planes[plane].m.userptr = b->m.planes[plane].m.userptr; v4l2_planes[plane].length = b->m.planes[plane].length; } } if (b->memory == V4L2_MEMORY_DMABUF) { for (plane = 0; plane < vb->num_planes; ++plane) { v4l2_planes[plane].m.fd = b->m.planes[plane].m.fd; v4l2_planes[plane].length = b->m.planes[plane].length; v4l2_planes[plane].data_offset = b->m.planes[plane].data_offset; } } } else { /* * Single-planar buffers do not use planes array, * so fill in relevant v4l2_buffer struct fields instead. * In videobuf we use our internal V4l2_planes struct for * single-planar buffers as well, for simplicity. */ if (V4L2_TYPE_IS_OUTPUT(b->type)) { v4l2_planes[0].bytesused = b->bytesused; v4l2_planes[0].data_offset = 0; } if (b->memory == V4L2_MEMORY_USERPTR) { v4l2_planes[0].m.userptr = b->m.userptr; v4l2_planes[0].length = b->length; } if (b->memory == V4L2_MEMORY_DMABUF) { v4l2_planes[0].m.fd = b->m.fd; v4l2_planes[0].length = b->length; v4l2_planes[0].data_offset = 0; } } vb->v4l2_buf.field = b->field; vb->v4l2_buf.timestamp = b->timestamp; vb->v4l2_buf.flags = b->flags & ~V4L2_BUFFER_MASK_FLAGS; } /** * __qbuf_userptr() - handle qbuf of a USERPTR buffer */ static int __qbuf_userptr(struct vb2_buffer *vb, const struct v4l2_buffer *b) { struct v4l2_plane planes[VIDEO_MAX_PLANES]; struct vb2_queue *q = vb->vb2_queue; void *mem_priv; unsigned int plane; int ret; int write = !V4L2_TYPE_IS_OUTPUT(q->type); /* Copy relevant information provided by the userspace */ __fill_vb2_buffer(vb, b, planes); for (plane = 0; plane < vb->num_planes; ++plane) { /* Skip the plane if already verified */ if (vb->v4l2_planes[plane].m.userptr && vb->v4l2_planes[plane].m.userptr == planes[plane].m.userptr && vb->v4l2_planes[plane].length == planes[plane].length) continue; dprintk(3, "qbuf: userspace address for plane %d changed, " "reacquiring memory\n", plane); /* Check if the provided plane buffer is large enough */ if (planes[plane].length < q->plane_sizes[plane]) { ret = -EINVAL; goto err; } /* Release previously acquired memory if present */ if (vb->planes[plane].mem_priv) call_memop(q, put_userptr, vb->planes[plane].mem_priv); vb->planes[plane].mem_priv = NULL; vb->v4l2_planes[plane].m.userptr = 0; vb->v4l2_planes[plane].length = 0; /* Acquire each plane's memory */ mem_priv = call_memop(q, get_userptr, q->alloc_ctx[plane], planes[plane].m.userptr, planes[plane].length, write); if (IS_ERR_OR_NULL(mem_priv)) { dprintk(1, "qbuf: failed acquiring userspace " "memory for plane %d\n", plane); ret = mem_priv ? PTR_ERR(mem_priv) : -EINVAL; goto err; } vb->planes[plane].mem_priv = mem_priv; } /* * Call driver-specific initialization on the newly acquired buffer, * if provided. */ ret = call_qop(q, buf_init, vb); if (ret) { dprintk(1, "qbuf: buffer initialization failed\n"); goto err; } /* * Now that everything is in order, copy relevant information * provided by userspace. */ for (plane = 0; plane < vb->num_planes; ++plane) vb->v4l2_planes[plane] = planes[plane]; return 0; err: /* In case of errors, release planes that were already acquired */ for (plane = 0; plane < vb->num_planes; ++plane) { if (vb->planes[plane].mem_priv) call_memop(q, put_userptr, vb->planes[plane].mem_priv); vb->planes[plane].mem_priv = NULL; vb->v4l2_planes[plane].m.userptr = 0; vb->v4l2_planes[plane].length = 0; } return ret; } /** * __qbuf_mmap() - handle qbuf of an MMAP buffer */ static int __qbuf_mmap(struct vb2_buffer *vb, const struct v4l2_buffer *b) { __fill_vb2_buffer(vb, b, vb->v4l2_planes); return 0; } /** * __qbuf_dmabuf() - handle qbuf of a DMABUF buffer */ static int __qbuf_dmabuf(struct vb2_buffer *vb, const struct v4l2_buffer *b) { struct v4l2_plane planes[VIDEO_MAX_PLANES]; struct vb2_queue *q = vb->vb2_queue; void *mem_priv; unsigned int plane; int ret; int write = !V4L2_TYPE_IS_OUTPUT(q->type); /* Verify and copy relevant information provided by the userspace */ __fill_vb2_buffer(vb, b, planes); for (plane = 0; plane < vb->num_planes; ++plane) { struct dma_buf *dbuf = dma_buf_get(planes[plane].m.fd); if (IS_ERR_OR_NULL(dbuf)) { dprintk(1, "qbuf: invalid dmabuf fd for plane %d\n", plane); ret = -EINVAL; goto err; } /* use DMABUF size if length is not provided */ if (planes[plane].length == 0) planes[plane].length = dbuf->size; if (planes[plane].length < planes[plane].data_offset + q->plane_sizes[plane]) { ret = -EINVAL; goto err; } /* Skip the plane if already verified */ if (dbuf == vb->planes[plane].dbuf && vb->v4l2_planes[plane].length == planes[plane].length) { dma_buf_put(dbuf); continue; } dprintk(1, "qbuf: buffer for plane %d changed\n", plane); /* Release previously acquired memory if present */ __vb2_plane_dmabuf_put(q, &vb->planes[plane]); memset(&vb->v4l2_planes[plane], 0, sizeof(struct v4l2_plane)); /* Acquire each plane's memory */ mem_priv = call_memop(q, attach_dmabuf, q->alloc_ctx[plane], dbuf, planes[plane].length, write); if (IS_ERR(mem_priv)) { dprintk(1, "qbuf: failed to attach dmabuf\n"); ret = PTR_ERR(mem_priv); dma_buf_put(dbuf); goto err; } vb->planes[plane].dbuf = dbuf; vb->planes[plane].mem_priv = mem_priv; } /* TODO: This pins the buffer(s) with dma_buf_map_attachment()).. but * really we want to do this just before the DMA, not while queueing * the buffer(s).. */ for (plane = 0; plane < vb->num_planes; ++plane) { ret = call_memop(q, map_dmabuf, vb->planes[plane].mem_priv); if (ret) { dprintk(1, "qbuf: failed to map dmabuf for plane %d\n", plane); goto err; } vb->planes[plane].dbuf_mapped = 1; } /* * Call driver-specific initialization on the newly acquired buffer, * if provided. */ ret = call_qop(q, buf_init, vb); if (ret) { dprintk(1, "qbuf: buffer initialization failed\n"); goto err; } /* * Now that everything is in order, copy relevant information * provided by userspace. */ for (plane = 0; plane < vb->num_planes; ++plane) vb->v4l2_planes[plane] = planes[plane]; return 0; err: /* In case of errors, release planes that were already acquired */ __vb2_buf_dmabuf_put(vb); return ret; } /** * __enqueue_in_driver() - enqueue a vb2_buffer in driver for processing */ static void __enqueue_in_driver(struct vb2_buffer *vb) { struct vb2_queue *q = vb->vb2_queue; unsigned int plane; vb->state = VB2_BUF_STATE_ACTIVE; atomic_inc(&q->queued_count); /* sync buffers */ for (plane = 0; plane < vb->num_planes; ++plane) call_memop(q, prepare, vb->planes[plane].mem_priv); q->ops->buf_queue(vb); } static int __buf_prepare(struct vb2_buffer *vb, const struct v4l2_buffer *b) { struct vb2_queue *q = vb->vb2_queue; int ret; switch (q->memory) { case V4L2_MEMORY_MMAP: ret = __qbuf_mmap(vb, b); break; case V4L2_MEMORY_USERPTR: ret = __qbuf_userptr(vb, b); break; case V4L2_MEMORY_DMABUF: ret = __qbuf_dmabuf(vb, b); break; default: WARN(1, "Invalid queue type\n"); ret = -EINVAL; } if (!ret) ret = call_qop(q, buf_prepare, vb); if (ret) dprintk(1, "qbuf: buffer preparation failed: %d\n", ret); else vb->state = VB2_BUF_STATE_PREPARED; return ret; } /** * vb2_prepare_buf() - Pass ownership of a buffer from userspace to the kernel * @q: videobuf2 queue * @b: buffer structure passed from userspace to vidioc_prepare_buf * handler in driver * * Should be called from vidioc_prepare_buf ioctl handler of a driver. * This function: * 1) verifies the passed buffer, * 2) calls buf_prepare callback in the driver (if provided), in which * driver-specific buffer initialization can be performed, * * The return values from this function are intended to be directly returned * from vidioc_prepare_buf handler in driver. */ int vb2_prepare_buf(struct vb2_queue *q, struct v4l2_buffer *b) { struct vb2_buffer *vb; int ret; if (q->fileio) { dprintk(1, "%s(): file io in progress\n", __func__); return -EBUSY; } if (b->type != q->type) { dprintk(1, "%s(): invalid buffer type\n", __func__); return -EINVAL; } if (b->index >= q->num_buffers) { dprintk(1, "%s(): buffer index out of range\n", __func__); return -EINVAL; } vb = q->bufs[b->index]; if (NULL == vb) { /* Should never happen */ dprintk(1, "%s(): buffer is NULL\n", __func__); return -EINVAL; } if (b->memory != q->memory) { dprintk(1, "%s(): invalid memory type\n", __func__); return -EINVAL; } if (vb->state != VB2_BUF_STATE_DEQUEUED) { dprintk(1, "%s(): invalid buffer state %d\n", __func__, vb->state); return -EINVAL; } ret = __verify_planes_array(vb, b); if (ret < 0) return ret; ret = __buf_prepare(vb, b); if (ret < 0) return ret; __fill_v4l2_buffer(vb, b); return 0; } EXPORT_SYMBOL_GPL(vb2_prepare_buf); /** * vb2_qbuf() - Queue a buffer from userspace * @q: videobuf2 queue * @b: buffer structure passed from userspace to vidioc_qbuf handler * in driver * * Should be called from vidioc_qbuf ioctl handler of a driver. * This function: * 1) verifies the passed buffer, * 2) if necessary, calls buf_prepare callback in the driver (if provided), in * which driver-specific buffer initialization can be performed, * 3) if streaming is on, queues the buffer in driver by the means of buf_queue * callback for processing. * * The return values from this function are intended to be directly returned * from vidioc_qbuf handler in driver. */ int vb2_qbuf(struct vb2_queue *q, struct v4l2_buffer *b) { struct rw_semaphore *mmap_sem = NULL; struct vb2_buffer *vb; int ret = 0; /* * In case of user pointer buffers vb2 allocator needs to get direct * access to userspace pages. This requires getting read access on * mmap semaphore in the current process structure. The same * semaphore is taken before calling mmap operation, while both mmap * and qbuf are called by the driver or v4l2 core with driver's lock * held. To avoid a AB-BA deadlock (mmap_sem then driver's lock in * mmap and driver's lock then mmap_sem in qbuf) the videobuf2 core * release driver's lock, takes mmap_sem and then takes again driver's * lock. * * To avoid race with other vb2 calls, which might be called after * releasing driver's lock, this operation is performed at the * beggining of qbuf processing. This way the queue status is * consistent after getting driver's lock back. */ if (q->memory == V4L2_MEMORY_USERPTR) { mmap_sem = ¤t->mm->mmap_sem; call_qop(q, wait_prepare, q); down_read(mmap_sem); call_qop(q, wait_finish, q); } if (q->fileio) { dprintk(1, "qbuf: file io in progress\n"); ret = -EBUSY; goto unlock; } if (b->type != q->type) { dprintk(1, "qbuf: invalid buffer type\n"); ret = -EINVAL; goto unlock; } if (b->index >= q->num_buffers) { dprintk(1, "qbuf: buffer index out of range\n"); ret = -EINVAL; goto unlock; } vb = q->bufs[b->index]; if (NULL == vb) { /* Should never happen */ dprintk(1, "qbuf: buffer is NULL\n"); ret = -EINVAL; goto unlock; } if (b->memory != q->memory) { dprintk(1, "qbuf: invalid memory type\n"); ret = -EINVAL; goto unlock; } ret = __verify_planes_array(vb, b); if (ret) goto unlock; switch (vb->state) { case VB2_BUF_STATE_DEQUEUED: ret = __buf_prepare(vb, b); if (ret) goto unlock; case VB2_BUF_STATE_PREPARED: break; default: dprintk(1, "qbuf: buffer already in use\n"); ret = -EINVAL; goto unlock; } /* * Add to the queued buffers list, a buffer will stay on it until * dequeued in dqbuf. */ list_add_tail(&vb->queued_entry, &q->queued_list); vb->state = VB2_BUF_STATE_QUEUED; /* * If already streaming, give the buffer to driver for processing. * If not, the buffer will be given to driver on next streamon. */ if (q->streaming) __enqueue_in_driver(vb); /* Fill buffer information for the userspace */ __fill_v4l2_buffer(vb, b); dprintk(1, "qbuf of buffer %d succeeded\n", vb->v4l2_buf.index); unlock: if (mmap_sem) up_read(mmap_sem); return ret; } EXPORT_SYMBOL_GPL(vb2_qbuf); /** * __vb2_wait_for_done_vb() - wait for a buffer to become available * for dequeuing * * Will sleep if required for nonblocking == false. */ static int __vb2_wait_for_done_vb(struct vb2_queue *q, int nonblocking) { /* * All operations on vb_done_list are performed under done_lock * spinlock protection. However, buffers may be removed from * it and returned to userspace only while holding both driver's * lock and the done_lock spinlock. Thus we can be sure that as * long as we hold the driver's lock, the list will remain not * empty if list_empty() check succeeds. */ for (;;) { int ret; if (!q->streaming) { dprintk(1, "Streaming off, will not wait for buffers\n"); return -EINVAL; } if (!list_empty(&q->done_list)) { /* * Found a buffer that we were waiting for. */ break; } if (nonblocking) { dprintk(1, "Nonblocking and no buffers to dequeue, " "will not wait\n"); return -EAGAIN; } /* * We are streaming and blocking, wait for another buffer to * become ready or for streamoff. Driver's lock is released to * allow streamoff or qbuf to be called while waiting. */ call_qop(q, wait_prepare, q); /* * All locks have been released, it is safe to sleep now. */ dprintk(3, "Will sleep waiting for buffers\n"); ret = wait_event_interruptible(q->done_wq, !list_empty(&q->done_list) || !q->streaming); /* * We need to reevaluate both conditions again after reacquiring * the locks or return an error if one occurred. */ call_qop(q, wait_finish, q); if (ret) { dprintk(1, "Sleep was interrupted\n"); return ret; } } return 0; } /** * __vb2_get_done_vb() - get a buffer ready for dequeuing * * Will sleep if required for nonblocking == false. */ static int __vb2_get_done_vb(struct vb2_queue *q, struct vb2_buffer **vb, struct v4l2_buffer *b, int nonblocking) { unsigned long flags; int ret; /* * Wait for at least one buffer to become available on the done_list. */ ret = __vb2_wait_for_done_vb(q, nonblocking); if (ret) return ret; /* * Driver's lock has been held since we last verified that done_list * is not empty, so no need for another list_empty(done_list) check. */ spin_lock_irqsave(&q->done_lock, flags); *vb = list_first_entry(&q->done_list, struct vb2_buffer, done_entry); /* * Only remove the buffer from done_list if v4l2_buffer can handle all * the planes. */ ret = __verify_planes_array(*vb, b); if (!ret) list_del(&(*vb)->done_entry); spin_unlock_irqrestore(&q->done_lock, flags); return ret; } /** * vb2_wait_for_all_buffers() - wait until all buffers are given back to vb2 * @q: videobuf2 queue * * This function will wait until all buffers that have been given to the driver * by buf_queue() are given back to vb2 with vb2_buffer_done(). It doesn't call * wait_prepare, wait_finish pair. It is intended to be called with all locks * taken, for example from stop_streaming() callback. */ int vb2_wait_for_all_buffers(struct vb2_queue *q) { if (!q->streaming) { dprintk(1, "Streaming off, will not wait for buffers\n"); return -EINVAL; } wait_event(q->done_wq, !atomic_read(&q->queued_count)); return 0; } EXPORT_SYMBOL_GPL(vb2_wait_for_all_buffers); /** * __vb2_dqbuf() - bring back the buffer to the DEQUEUED state */ static void __vb2_dqbuf(struct vb2_buffer *vb) { struct vb2_queue *q = vb->vb2_queue; unsigned int i; /* nothing to do if the buffer is already dequeued */ if (vb->state == VB2_BUF_STATE_DEQUEUED) return; vb->state = VB2_BUF_STATE_DEQUEUED; /* unmap DMABUF buffer */ if (q->memory == V4L2_MEMORY_DMABUF) for (i = 0; i < vb->num_planes; ++i) { if (!vb->planes[i].dbuf_mapped) continue; call_memop(q, unmap_dmabuf, vb->planes[i].mem_priv); vb->planes[i].dbuf_mapped = 0; } } /** * vb2_dqbuf() - Dequeue a buffer to the userspace * @q: videobuf2 queue * @b: buffer structure passed from userspace to vidioc_dqbuf handler * in driver * @nonblocking: if true, this call will not sleep waiting for a buffer if no * buffers ready for dequeuing are present. Normally the driver * would be passing (file->f_flags & O_NONBLOCK) here * * Should be called from vidioc_dqbuf ioctl handler of a driver. * This function: * 1) verifies the passed buffer, * 2) calls buf_finish callback in the driver (if provided), in which * driver can perform any additional operations that may be required before * returning the buffer to userspace, such as cache sync, * 3) the buffer struct members are filled with relevant information for * the userspace. * * The return values from this function are intended to be directly returned * from vidioc_dqbuf handler in driver. */ int vb2_dqbuf(struct vb2_queue *q, struct v4l2_buffer *b, bool nonblocking) { struct vb2_buffer *vb = NULL; int ret; if (q->fileio) { dprintk(1, "dqbuf: file io in progress\n"); return -EBUSY; } if (b->type != q->type) { dprintk(1, "dqbuf: invalid buffer type\n"); return -EINVAL; } ret = __vb2_get_done_vb(q, &vb, b, nonblocking); if (ret < 0) return ret; ret = call_qop(q, buf_finish, vb); if (ret) { dprintk(1, "dqbuf: buffer finish failed\n"); return ret; } switch (vb->state) { case VB2_BUF_STATE_DONE: dprintk(3, "dqbuf: Returning done buffer\n"); break; case VB2_BUF_STATE_ERROR: dprintk(3, "dqbuf: Returning done buffer with errors\n"); break; default: dprintk(1, "dqbuf: Invalid buffer state\n"); return -EINVAL; } /* Fill buffer information for the userspace */ __fill_v4l2_buffer(vb, b); /* Remove from videobuf queue */ list_del(&vb->queued_entry); /* go back to dequeued state */ __vb2_dqbuf(vb); dprintk(1, "dqbuf of buffer %d, with state %d\n", vb->v4l2_buf.index, vb->state); return 0; } EXPORT_SYMBOL_GPL(vb2_dqbuf); /** * __vb2_queue_cancel() - cancel and stop (pause) streaming * * Removes all queued buffers from driver's queue and all buffers queued by * userspace from videobuf's queue. Returns to state after reqbufs. */ static void __vb2_queue_cancel(struct vb2_queue *q) { unsigned int i; /* * Tell driver to stop all transactions and release all queued * buffers. */ if (q->streaming) call_qop(q, stop_streaming, q); q->streaming = 0; /* * Remove all buffers from videobuf's list... */ INIT_LIST_HEAD(&q->queued_list); /* * ...and done list; userspace will not receive any buffers it * has not already dequeued before initiating cancel. */ INIT_LIST_HEAD(&q->done_list); atomic_set(&q->queued_count, 0); wake_up_all(&q->done_wq); /* * Reinitialize all buffers for next use. */ for (i = 0; i < q->num_buffers; ++i) __vb2_dqbuf(q->bufs[i]); } /** * vb2_streamon - start streaming * @q: videobuf2 queue * @type: type argument passed from userspace to vidioc_streamon handler * * Should be called from vidioc_streamon handler of a driver. * This function: * 1) verifies current state * 2) passes any previously queued buffers to the driver and starts streaming * * The return values from this function are intended to be directly returned * from vidioc_streamon handler in the driver. */ int vb2_streamon(struct vb2_queue *q, enum v4l2_buf_type type) { struct vb2_buffer *vb; int ret; if (q->fileio) { dprintk(1, "streamon: file io in progress\n"); return -EBUSY; } if (type != q->type) { dprintk(1, "streamon: invalid stream type\n"); return -EINVAL; } if (q->streaming) { dprintk(1, "streamon: already streaming\n"); return -EBUSY; } /* * If any buffers were queued before streamon, * we can now pass them to driver for processing. */ list_for_each_entry(vb, &q->queued_list, queued_entry) __enqueue_in_driver(vb); /* * Let driver notice that streaming state has been enabled. */ ret = call_qop(q, start_streaming, q, atomic_read(&q->queued_count)); if (ret) { dprintk(1, "streamon: driver refused to start streaming\n"); __vb2_queue_cancel(q); return ret; } q->streaming = 1; dprintk(3, "Streamon successful\n"); return 0; } EXPORT_SYMBOL_GPL(vb2_streamon); /** * vb2_streamoff - stop streaming * @q: videobuf2 queue * @type: type argument passed from userspace to vidioc_streamoff handler * * Should be called from vidioc_streamoff handler of a driver. * This function: * 1) verifies current state, * 2) stop streaming and dequeues any queued buffers, including those previously * passed to the driver (after waiting for the driver to finish). * * This call can be used for pausing playback. * The return values from this function are intended to be directly returned * from vidioc_streamoff handler in the driver */ int vb2_streamoff(struct vb2_queue *q, enum v4l2_buf_type type) { if (q->fileio) { dprintk(1, "streamoff: file io in progress\n"); return -EBUSY; } if (type != q->type) { dprintk(1, "streamoff: invalid stream type\n"); return -EINVAL; } if (!q->streaming) { dprintk(1, "streamoff: not streaming\n"); return -EINVAL; } /* * Cancel will pause streaming and remove all buffers from the driver * and videobuf, effectively returning control over them to userspace. */ __vb2_queue_cancel(q); dprintk(3, "Streamoff successful\n"); return 0; } EXPORT_SYMBOL_GPL(vb2_streamoff); /** * __find_plane_by_offset() - find plane associated with the given offset off */ static int __find_plane_by_offset(struct vb2_queue *q, unsigned long off, unsigned int *_buffer, unsigned int *_plane) { struct vb2_buffer *vb; unsigned int buffer, plane; /* * Go over all buffers and their planes, comparing the given offset * with an offset assigned to each plane. If a match is found, * return its buffer and plane numbers. */ for (buffer = 0; buffer < q->num_buffers; ++buffer) { vb = q->bufs[buffer]; for (plane = 0; plane < vb->num_planes; ++plane) { if (vb->v4l2_planes[plane].m.mem_offset == off) { *_buffer = buffer; *_plane = plane; return 0; } } } return -EINVAL; } /** * vb2_expbuf() - Export a buffer as a file descriptor * @q: videobuf2 queue * @eb: export buffer structure passed from userspace to vidioc_expbuf * handler in driver * * The return values from this function are intended to be directly returned * from vidioc_expbuf handler in driver. */ int vb2_expbuf(struct vb2_queue *q, struct v4l2_exportbuffer *eb) { struct vb2_buffer *vb = NULL; struct vb2_plane *vb_plane; int ret; struct dma_buf *dbuf; if (q->memory != V4L2_MEMORY_MMAP) { dprintk(1, "Queue is not currently set up for mmap\n"); return -EINVAL; } if (!q->mem_ops->get_dmabuf) { dprintk(1, "Queue does not support DMA buffer exporting\n"); return -EINVAL; } if (eb->flags & ~O_CLOEXEC) { dprintk(1, "Queue does support only O_CLOEXEC flag\n"); return -EINVAL; } if (eb->type != q->type) { dprintk(1, "qbuf: invalid buffer type\n"); return -EINVAL; } if (eb->index >= q->num_buffers) { dprintk(1, "buffer index out of range\n"); return -EINVAL; } vb = q->bufs[eb->index]; if (eb->plane >= vb->num_planes) { dprintk(1, "buffer plane out of range\n"); return -EINVAL; } vb_plane = &vb->planes[eb->plane]; dbuf = call_memop(q, get_dmabuf, vb_plane->mem_priv); if (IS_ERR_OR_NULL(dbuf)) { dprintk(1, "Failed to export buffer %d, plane %d\n", eb->index, eb->plane); return -EINVAL; } ret = dma_buf_fd(dbuf, eb->flags); if (ret < 0) { dprintk(3, "buffer %d, plane %d failed to export (%d)\n", eb->index, eb->plane, ret); dma_buf_put(dbuf); return ret; } dprintk(3, "buffer %d, plane %d exported as %d descriptor\n", eb->index, eb->plane, ret); eb->fd = ret; return 0; } EXPORT_SYMBOL_GPL(vb2_expbuf); /** * vb2_mmap() - map video buffers into application address space * @q: videobuf2 queue * @vma: vma passed to the mmap file operation handler in the driver * * Should be called from mmap file operation handler of a driver. * This function maps one plane of one of the available video buffers to * userspace. To map whole video memory allocated on reqbufs, this function * has to be called once per each plane per each buffer previously allocated. * * When the userspace application calls mmap, it passes to it an offset returned * to it earlier by the means of vidioc_querybuf handler. That offset acts as * a "cookie", which is then used to identify the plane to be mapped. * This function finds a plane with a matching offset and a mapping is performed * by the means of a provided memory operation. * * The return values from this function are intended to be directly returned * from the mmap handler in driver. */ int vb2_mmap(struct vb2_queue *q, struct vm_area_struct *vma) { unsigned long off = vma->vm_pgoff << PAGE_SHIFT; struct vb2_buffer *vb; unsigned int buffer, plane; int ret; unsigned long length; if (q->memory != V4L2_MEMORY_MMAP) { dprintk(1, "Queue is not currently set up for mmap\n"); return -EINVAL; } /* * Check memory area access mode. */ if (!(vma->vm_flags & VM_SHARED)) { dprintk(1, "Invalid vma flags, VM_SHARED needed\n"); return -EINVAL; } if (V4L2_TYPE_IS_OUTPUT(q->type)) { if (!(vma->vm_flags & VM_WRITE)) { dprintk(1, "Invalid vma flags, VM_WRITE needed\n"); return -EINVAL; } } else { if (!(vma->vm_flags & VM_READ)) { dprintk(1, "Invalid vma flags, VM_READ needed\n"); return -EINVAL; } } /* * Find the plane corresponding to the offset passed by userspace. */ ret = __find_plane_by_offset(q, off, &buffer, &plane); if (ret) return ret; vb = q->bufs[buffer]; /* * MMAP requires page_aligned buffers. * The buffer length was page_aligned at __vb2_buf_mem_alloc(), * so, we need to do the same here. */ length = PAGE_ALIGN(vb->v4l2_planes[plane].length); if (length < (vma->vm_end - vma->vm_start)) { dprintk(1, "MMAP invalid, as it would overflow buffer length\n"); return -EINVAL; } ret = call_memop(q, mmap, vb->planes[plane].mem_priv, vma); if (ret) return ret; dprintk(3, "Buffer %d, plane %d successfully mapped\n", buffer, plane); return 0; } EXPORT_SYMBOL_GPL(vb2_mmap); #ifndef CONFIG_MMU unsigned long vb2_get_unmapped_area(struct vb2_queue *q, unsigned long addr, unsigned long len, unsigned long pgoff, unsigned long flags) { unsigned long off = pgoff << PAGE_SHIFT; struct vb2_buffer *vb; unsigned int buffer, plane; int ret; if (q->memory != V4L2_MEMORY_MMAP) { dprintk(1, "Queue is not currently set up for mmap\n"); return -EINVAL; } /* * Find the plane corresponding to the offset passed by userspace. */ ret = __find_plane_by_offset(q, off, &buffer, &plane); if (ret) return ret; vb = q->bufs[buffer]; return (unsigned long)vb2_plane_vaddr(vb, plane); } EXPORT_SYMBOL_GPL(vb2_get_unmapped_area); #endif static int __vb2_init_fileio(struct vb2_queue *q, int read); static int __vb2_cleanup_fileio(struct vb2_queue *q); /** * vb2_poll() - implements poll userspace operation * @q: videobuf2 queue * @file: file argument passed to the poll file operation handler * @wait: wait argument passed to the poll file operation handler * * This function implements poll file operation handler for a driver. * For CAPTURE queues, if a buffer is ready to be dequeued, the userspace will * be informed that the file descriptor of a video device is available for * reading. * For OUTPUT queues, if a buffer is ready to be dequeued, the file descriptor * will be reported as available for writing. * * If the driver uses struct v4l2_fh, then vb2_poll() will also check for any * pending events. * * The return values from this function are intended to be directly returned * from poll handler in driver. */ unsigned int vb2_poll(struct vb2_queue *q, struct file *file, poll_table *wait) { struct video_device *vfd = video_devdata(file); unsigned long req_events = poll_requested_events(wait); struct vb2_buffer *vb = NULL; unsigned int res = 0; unsigned long flags; if (test_bit(V4L2_FL_USES_V4L2_FH, &vfd->flags)) { struct v4l2_fh *fh = file->private_data; if (v4l2_event_pending(fh)) res = POLLPRI; else if (req_events & POLLPRI) poll_wait(file, &fh->wait, wait); } if (!V4L2_TYPE_IS_OUTPUT(q->type) && !(req_events & (POLLIN | POLLRDNORM))) return res; if (V4L2_TYPE_IS_OUTPUT(q->type) && !(req_events & (POLLOUT | POLLWRNORM))) return res; /* * Start file I/O emulator only if streaming API has not been used yet. */ if (q->num_buffers == 0 && q->fileio == NULL) { if (!V4L2_TYPE_IS_OUTPUT(q->type) && (q->io_modes & VB2_READ) && (req_events & (POLLIN | POLLRDNORM))) { if (__vb2_init_fileio(q, 1)) return res | POLLERR; } if (V4L2_TYPE_IS_OUTPUT(q->type) && (q->io_modes & VB2_WRITE) && (req_events & (POLLOUT | POLLWRNORM))) { if (__vb2_init_fileio(q, 0)) return res | POLLERR; /* * Write to OUTPUT queue can be done immediately. */ return res | POLLOUT | POLLWRNORM; } } /* * There is nothing to wait for if no buffers have already been queued. */ if (list_empty(&q->queued_list)) return res | POLLERR; if (list_empty(&q->done_list)) poll_wait(file, &q->done_wq, wait); /* * Take first buffer available for dequeuing. */ spin_lock_irqsave(&q->done_lock, flags); if (!list_empty(&q->done_list)) vb = list_first_entry(&q->done_list, struct vb2_buffer, done_entry); spin_unlock_irqrestore(&q->done_lock, flags); if (vb && (vb->state == VB2_BUF_STATE_DONE || vb->state == VB2_BUF_STATE_ERROR)) { return (V4L2_TYPE_IS_OUTPUT(q->type)) ? res | POLLOUT | POLLWRNORM : res | POLLIN | POLLRDNORM; } return res; } EXPORT_SYMBOL_GPL(vb2_poll); /** * vb2_queue_init() - initialize a videobuf2 queue * @q: videobuf2 queue; this structure should be allocated in driver * * The vb2_queue structure should be allocated by the driver. The driver is * responsible of clearing it's content and setting initial values for some * required entries before calling this function. * q->ops, q->mem_ops, q->type and q->io_modes are mandatory. Please refer * to the struct vb2_queue description in include/media/videobuf2-core.h * for more information. */ int vb2_queue_init(struct vb2_queue *q) { /* * Sanity check */ if (WARN_ON(!q) || WARN_ON(!q->ops) || WARN_ON(!q->mem_ops) || WARN_ON(!q->type) || WARN_ON(!q->io_modes) || WARN_ON(!q->ops->queue_setup) || WARN_ON(!q->ops->buf_queue) || WARN_ON(q->timestamp_type & ~V4L2_BUF_FLAG_TIMESTAMP_MASK)) return -EINVAL; /* Warn that the driver should choose an appropriate timestamp type */ WARN_ON(q->timestamp_type == V4L2_BUF_FLAG_TIMESTAMP_UNKNOWN); INIT_LIST_HEAD(&q->queued_list); INIT_LIST_HEAD(&q->done_list); spin_lock_init(&q->done_lock); init_waitqueue_head(&q->done_wq); if (q->buf_struct_size == 0) q->buf_struct_size = sizeof(struct vb2_buffer); return 0; } EXPORT_SYMBOL_GPL(vb2_queue_init); /** * vb2_queue_release() - stop streaming, release the queue and free memory * @q: videobuf2 queue * * This function stops streaming and performs necessary clean ups, including * freeing video buffer memory. The driver is responsible for freeing * the vb2_queue structure itself. */ void vb2_queue_release(struct vb2_queue *q) { __vb2_cleanup_fileio(q); __vb2_queue_cancel(q); __vb2_queue_free(q, q->num_buffers); } EXPORT_SYMBOL_GPL(vb2_queue_release); /** * struct vb2_fileio_buf - buffer context used by file io emulator * * vb2 provides a compatibility layer and emulator of file io (read and * write) calls on top of streaming API. This structure is used for * tracking context related to the buffers. */ struct vb2_fileio_buf { void *vaddr; unsigned int size; unsigned int pos; unsigned int queued:1; }; /** * struct vb2_fileio_data - queue context used by file io emulator * * vb2 provides a compatibility layer and emulator of file io (read and * write) calls on top of streaming API. For proper operation it required * this structure to save the driver state between each call of the read * or write function. */ struct vb2_fileio_data { struct v4l2_requestbuffers req; struct v4l2_buffer b; struct vb2_fileio_buf bufs[VIDEO_MAX_FRAME]; unsigned int index; unsigned int q_count; unsigned int dq_count; unsigned int flags; }; /** * __vb2_init_fileio() - initialize file io emulator * @q: videobuf2 queue * @read: mode selector (1 means read, 0 means write) */ static int __vb2_init_fileio(struct vb2_queue *q, int read) { struct vb2_fileio_data *fileio; int i, ret; unsigned int count = 0; /* * Sanity check */ if ((read && !(q->io_modes & VB2_READ)) || (!read && !(q->io_modes & VB2_WRITE))) BUG(); /* * Check if device supports mapping buffers to kernel virtual space. */ if (!q->mem_ops->vaddr) return -EBUSY; /* * Check if streaming api has not been already activated. */ if (q->streaming || q->num_buffers > 0) return -EBUSY; /* * Start with count 1, driver can increase it in queue_setup() */ count = 1; dprintk(3, "setting up file io: mode %s, count %d, flags %08x\n", (read) ? "read" : "write", count, q->io_flags); fileio = kzalloc(sizeof(struct vb2_fileio_data), GFP_KERNEL); if (fileio == NULL) return -ENOMEM; fileio->flags = q->io_flags; /* * Request buffers and use MMAP type to force driver * to allocate buffers by itself. */ fileio->req.count = count; fileio->req.memory = V4L2_MEMORY_MMAP; fileio->req.type = q->type; ret = vb2_reqbufs(q, &fileio->req); if (ret) goto err_kfree; /* * Check if plane_count is correct * (multiplane buffers are not supported). */ if (q->bufs[0]->num_planes != 1) { ret = -EBUSY; goto err_reqbufs; } /* * Get kernel address of each buffer. */ for (i = 0; i < q->num_buffers; i++) { fileio->bufs[i].vaddr = vb2_plane_vaddr(q->bufs[i], 0); if (fileio->bufs[i].vaddr == NULL) goto err_reqbufs; fileio->bufs[i].size = vb2_plane_size(q->bufs[i], 0); } /* * Read mode requires pre queuing of all buffers. */ if (read) { /* * Queue all buffers. */ for (i = 0; i < q->num_buffers; i++) { struct v4l2_buffer *b = &fileio->b; memset(b, 0, sizeof(*b)); b->type = q->type; b->memory = q->memory; b->index = i; ret = vb2_qbuf(q, b); if (ret) goto err_reqbufs; fileio->bufs[i].queued = 1; } /* * Start streaming. */ ret = vb2_streamon(q, q->type); if (ret) goto err_reqbufs; } q->fileio = fileio; return ret; err_reqbufs: fileio->req.count = 0; vb2_reqbufs(q, &fileio->req); err_kfree: kfree(fileio); return ret; } /** * __vb2_cleanup_fileio() - free resourced used by file io emulator * @q: videobuf2 queue */ static int __vb2_cleanup_fileio(struct vb2_queue *q) { struct vb2_fileio_data *fileio = q->fileio; if (fileio) { /* * Hack fileio context to enable direct calls to vb2 ioctl * interface. */ q->fileio = NULL; vb2_streamoff(q, q->type); fileio->req.count = 0; vb2_reqbufs(q, &fileio->req); kfree(fileio); dprintk(3, "file io emulator closed\n"); } return 0; } /** * __vb2_perform_fileio() - perform a single file io (read or write) operation * @q: videobuf2 queue * @data: pointed to target userspace buffer * @count: number of bytes to read or write * @ppos: file handle position tracking pointer * @nonblock: mode selector (1 means blocking calls, 0 means nonblocking) * @read: access mode selector (1 means read, 0 means write) */ static size_t __vb2_perform_fileio(struct vb2_queue *q, char __user *data, size_t count, loff_t *ppos, int nonblock, int read) { struct vb2_fileio_data *fileio; struct vb2_fileio_buf *buf; int ret, index; dprintk(3, "file io: mode %s, offset %ld, count %zd, %sblocking\n", read ? "read" : "write", (long)*ppos, count, nonblock ? "non" : ""); if (!data) return -EINVAL; /* * Initialize emulator on first call. */ if (!q->fileio) { ret = __vb2_init_fileio(q, read); dprintk(3, "file io: vb2_init_fileio result: %d\n", ret); if (ret) return ret; } fileio = q->fileio; /* * Hack fileio context to enable direct calls to vb2 ioctl interface. * The pointer will be restored before returning from this function. */ q->fileio = NULL; index = fileio->index; buf = &fileio->bufs[index]; /* * Check if we need to dequeue the buffer. */ if (buf->queued) { struct vb2_buffer *vb; /* * Call vb2_dqbuf to get buffer back. */ memset(&fileio->b, 0, sizeof(fileio->b)); fileio->b.type = q->type; fileio->b.memory = q->memory; fileio->b.index = index; ret = vb2_dqbuf(q, &fileio->b, nonblock); dprintk(5, "file io: vb2_dqbuf result: %d\n", ret); if (ret) goto end; fileio->dq_count += 1; /* * Get number of bytes filled by the driver */ vb = q->bufs[index]; buf->size = vb2_get_plane_payload(vb, 0); buf->queued = 0; } /* * Limit count on last few bytes of the buffer. */ if (buf->pos + count > buf->size) { count = buf->size - buf->pos; dprintk(5, "reducing read count: %zd\n", count); } /* * Transfer data to userspace. */ dprintk(3, "file io: copying %zd bytes - buffer %d, offset %u\n", count, index, buf->pos); if (read) ret = copy_to_user(data, buf->vaddr + buf->pos, count); else ret = copy_from_user(buf->vaddr + buf->pos, data, count); if (ret) { dprintk(3, "file io: error copying data\n"); ret = -EFAULT; goto end; } /* * Update counters. */ buf->pos += count; *ppos += count; /* * Queue next buffer if required. */ if (buf->pos == buf->size || (!read && (fileio->flags & VB2_FILEIO_WRITE_IMMEDIATELY))) { /* * Check if this is the last buffer to read. */ if (read && (fileio->flags & VB2_FILEIO_READ_ONCE) && fileio->dq_count == 1) { dprintk(3, "file io: read limit reached\n"); /* * Restore fileio pointer and release the context. */ q->fileio = fileio; return __vb2_cleanup_fileio(q); } /* * Call vb2_qbuf and give buffer to the driver. */ memset(&fileio->b, 0, sizeof(fileio->b)); fileio->b.type = q->type; fileio->b.memory = q->memory; fileio->b.index = index; fileio->b.bytesused = buf->pos; ret = vb2_qbuf(q, &fileio->b); dprintk(5, "file io: vb2_dbuf result: %d\n", ret); if (ret) goto end; /* * Buffer has been queued, update the status */ buf->pos = 0; buf->queued = 1; buf->size = q->bufs[0]->v4l2_planes[0].length; fileio->q_count += 1; /* * Switch to the next buffer */ fileio->index = (index + 1) % q->num_buffers; /* * Start streaming if required. */ if (!read && !q->streaming) { ret = vb2_streamon(q, q->type); if (ret) goto end; } } /* * Return proper number of bytes processed. */ if (ret == 0) ret = count; end: /* * Restore the fileio context and block vb2 ioctl interface. */ q->fileio = fileio; return ret; } size_t vb2_read(struct vb2_queue *q, char __user *data, size_t count, loff_t *ppos, int nonblocking) { return __vb2_perform_fileio(q, data, count, ppos, nonblocking, 1); } EXPORT_SYMBOL_GPL(vb2_read); size_t vb2_write(struct vb2_queue *q, char __user *data, size_t count, loff_t *ppos, int nonblocking) { return __vb2_perform_fileio(q, data, count, ppos, nonblocking, 0); } EXPORT_SYMBOL_GPL(vb2_write); /* * The following functions are not part of the vb2 core API, but are helper * functions that plug into struct v4l2_ioctl_ops, struct v4l2_file_operations * and struct vb2_ops. * They contain boilerplate code that most if not all drivers have to do * and so they simplify the driver code. */ /* The queue is busy if there is a owner and you are not that owner. */ static inline bool vb2_queue_is_busy(struct video_device *vdev, struct file *file) { return vdev->queue->owner && vdev->queue->owner != file->private_data; } /* vb2 ioctl helpers */ int vb2_ioctl_reqbufs(struct file *file, void *priv, struct v4l2_requestbuffers *p) { struct video_device *vdev = video_devdata(file); int res = __verify_memory_type(vdev->queue, p->memory, p->type); if (res) return res; if (vb2_queue_is_busy(vdev, file)) return -EBUSY; res = __reqbufs(vdev->queue, p); /* If count == 0, then the owner has released all buffers and he is no longer owner of the queue. Otherwise we have a new owner. */ if (res == 0) vdev->queue->owner = p->count ? file->private_data : NULL; return res; } EXPORT_SYMBOL_GPL(vb2_ioctl_reqbufs); int vb2_ioctl_create_bufs(struct file *file, void *priv, struct v4l2_create_buffers *p) { struct video_device *vdev = video_devdata(file); int res = __verify_memory_type(vdev->queue, p->memory, p->format.type); p->index = vdev->queue->num_buffers; /* If count == 0, then just check if memory and type are valid. Any -EBUSY result from __verify_memory_type can be mapped to 0. */ if (p->count == 0) return res != -EBUSY ? res : 0; if (res) return res; if (vb2_queue_is_busy(vdev, file)) return -EBUSY; res = __create_bufs(vdev->queue, p); if (res == 0) vdev->queue->owner = file->private_data; return res; } EXPORT_SYMBOL_GPL(vb2_ioctl_create_bufs); int vb2_ioctl_prepare_buf(struct file *file, void *priv, struct v4l2_buffer *p) { struct video_device *vdev = video_devdata(file); if (vb2_queue_is_busy(vdev, file)) return -EBUSY; return vb2_prepare_buf(vdev->queue, p); } EXPORT_SYMBOL_GPL(vb2_ioctl_prepare_buf); int vb2_ioctl_querybuf(struct file *file, void *priv, struct v4l2_buffer *p) { struct video_device *vdev = video_devdata(file); /* No need to call vb2_queue_is_busy(), anyone can query buffers. */ return vb2_querybuf(vdev->queue, p); } EXPORT_SYMBOL_GPL(vb2_ioctl_querybuf); int vb2_ioctl_qbuf(struct file *file, void *priv, struct v4l2_buffer *p) { struct video_device *vdev = video_devdata(file); if (vb2_queue_is_busy(vdev, file)) return -EBUSY; return vb2_qbuf(vdev->queue, p); } EXPORT_SYMBOL_GPL(vb2_ioctl_qbuf); int vb2_ioctl_dqbuf(struct file *file, void *priv, struct v4l2_buffer *p) { struct video_device *vdev = video_devdata(file); if (vb2_queue_is_busy(vdev, file)) return -EBUSY; return vb2_dqbuf(vdev->queue, p, file->f_flags & O_NONBLOCK); } EXPORT_SYMBOL_GPL(vb2_ioctl_dqbuf); int vb2_ioctl_streamon(struct file *file, void *priv, enum v4l2_buf_type i) { struct video_device *vdev = video_devdata(file); if (vb2_queue_is_busy(vdev, file)) return -EBUSY; return vb2_streamon(vdev->queue, i); } EXPORT_SYMBOL_GPL(vb2_ioctl_streamon); int vb2_ioctl_streamoff(struct file *file, void *priv, enum v4l2_buf_type i) { struct video_device *vdev = video_devdata(file); if (vb2_queue_is_busy(vdev, file)) return -EBUSY; return vb2_streamoff(vdev->queue, i); } EXPORT_SYMBOL_GPL(vb2_ioctl_streamoff); int vb2_ioctl_expbuf(struct file *file, void *priv, struct v4l2_exportbuffer *p) { struct video_device *vdev = video_devdata(file); if (vb2_queue_is_busy(vdev, file)) return -EBUSY; return vb2_expbuf(vdev->queue, p); } EXPORT_SYMBOL_GPL(vb2_ioctl_expbuf); /* v4l2_file_operations helpers */ int vb2_fop_mmap(struct file *file, struct vm_area_struct *vma) { struct video_device *vdev = video_devdata(file); return vb2_mmap(vdev->queue, vma); } EXPORT_SYMBOL_GPL(vb2_fop_mmap); int vb2_fop_release(struct file *file) { struct video_device *vdev = video_devdata(file); if (file->private_data == vdev->queue->owner) { vb2_queue_release(vdev->queue); vdev->queue->owner = NULL; } return v4l2_fh_release(file); } EXPORT_SYMBOL_GPL(vb2_fop_release); ssize_t vb2_fop_write(struct file *file, char __user *buf, size_t count, loff_t *ppos) { struct video_device *vdev = video_devdata(file); struct mutex *lock = vdev->queue->lock ? vdev->queue->lock : vdev->lock; int err = -EBUSY; if (lock && mutex_lock_interruptible(lock)) return -ERESTARTSYS; if (vb2_queue_is_busy(vdev, file)) goto exit; err = vb2_write(vdev->queue, buf, count, ppos, file->f_flags & O_NONBLOCK); if (vdev->queue->fileio) vdev->queue->owner = file->private_data; exit: if (lock) mutex_unlock(lock); return err; } EXPORT_SYMBOL_GPL(vb2_fop_write); ssize_t vb2_fop_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) { struct video_device *vdev = video_devdata(file); struct mutex *lock = vdev->queue->lock ? vdev->queue->lock : vdev->lock; int err = -EBUSY; if (lock && mutex_lock_interruptible(lock)) return -ERESTARTSYS; if (vb2_queue_is_busy(vdev, file)) goto exit; err = vb2_read(vdev->queue, buf, count, ppos, file->f_flags & O_NONBLOCK); if (vdev->queue->fileio) vdev->queue->owner = file->private_data; exit: if (lock) mutex_unlock(lock); return err; } EXPORT_SYMBOL_GPL(vb2_fop_read); unsigned int vb2_fop_poll(struct file *file, poll_table *wait) { struct video_device *vdev = video_devdata(file); struct vb2_queue *q = vdev->queue; struct mutex *lock = q->lock ? q->lock : vdev->lock; unsigned long req_events = poll_requested_events(wait); unsigned res; void *fileio; bool must_lock = false; /* Try to be smart: only lock if polling might start fileio, otherwise locking will only introduce unwanted delays. */ if (q->num_buffers == 0 && q->fileio == NULL) { if (!V4L2_TYPE_IS_OUTPUT(q->type) && (q->io_modes & VB2_READ) && (req_events & (POLLIN | POLLRDNORM))) must_lock = true; else if (V4L2_TYPE_IS_OUTPUT(q->type) && (q->io_modes & VB2_WRITE) && (req_events & (POLLOUT | POLLWRNORM))) must_lock = true; } /* If locking is needed, but this helper doesn't know how, then you shouldn't be using this helper but you should write your own. */ WARN_ON(must_lock && !lock); if (must_lock && lock && mutex_lock_interruptible(lock)) return POLLERR; fileio = q->fileio; res = vb2_poll(vdev->queue, file, wait); /* If fileio was started, then we have a new queue owner. */ if (must_lock && !fileio && q->fileio) q->owner = file->private_data; if (must_lock && lock) mutex_unlock(lock); return res; } EXPORT_SYMBOL_GPL(vb2_fop_poll); #ifndef CONFIG_MMU unsigned long vb2_fop_get_unmapped_area(struct file *file, unsigned long addr, unsigned long len, unsigned long pgoff, unsigned long flags) { struct video_device *vdev = video_devdata(file); return vb2_get_unmapped_area(vdev->queue, addr, len, pgoff, flags); } EXPORT_SYMBOL_GPL(vb2_fop_get_unmapped_area); #endif /* vb2_ops helpers. Only use if vq->lock is non-NULL. */ void vb2_ops_wait_prepare(struct vb2_queue *vq) { mutex_unlock(vq->lock); } EXPORT_SYMBOL_GPL(vb2_ops_wait_prepare); void vb2_ops_wait_finish(struct vb2_queue *vq) { mutex_lock(vq->lock); } EXPORT_SYMBOL_GPL(vb2_ops_wait_finish); MODULE_DESCRIPTION("Driver helper framework for Video for Linux 2"); MODULE_AUTHOR("Pawel Osciak , Marek Szyprowski"); MODULE_LICENSE("GPL");