/* * 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 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, plane, 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) /** * __vb2_buf_mem_alloc() - allocate video memory for the given buffer */ static int __vb2_buf_mem_alloc(struct vb2_buffer *vb, unsigned long *plane_sizes) { struct vb2_queue *q = vb->vb2_queue; void *mem_priv; int plane; /* Allocate memory for all planes in this buffer */ for (plane = 0; plane < vb->num_planes; ++plane) { mem_priv = call_memop(q, plane, alloc, q->alloc_ctx[plane], plane_sizes[plane]); if (!mem_priv) goto free; /* Associate allocator private data with this plane */ vb->planes[plane].mem_priv = mem_priv; vb->v4l2_planes[plane].length = plane_sizes[plane]; } return 0; free: /* Free already allocated memory if one of the allocations failed */ for (; plane > 0; --plane) call_memop(q, plane, put, vb->planes[plane - 1].mem_priv); 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, plane, 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) { void *mem_priv = vb->planes[plane].mem_priv; if (mem_priv) { call_memop(q, plane, put_userptr, mem_priv); vb->planes[plane].mem_priv = NULL; } } } /** * __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 buffer, plane; struct vb2_buffer *vb; unsigned long off = 0; for (buffer = 0; buffer < q->num_buffers; ++buffer) { vb = q->bufs[buffer]; if (!vb) continue; for (plane = 0; plane < vb->num_planes; ++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 long plane_sizes[]) { 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 = 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, plane_sizes); 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[buffer] = vb; } q->num_buffers = buffer; __setup_offsets(q); dprintk(1, "Allocated %d buffers, %d plane(s) each\n", q->num_buffers, 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 buffer; struct vb2_buffer *vb; for (buffer = 0; 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 __vb2_buf_userptr_put(vb); } } /** * __vb2_queue_free() - free the queue - video memory and related information * and return the queue to an uninitialized state. Might be called even if the * queue has already been freed. */ static int __vb2_queue_free(struct vb2_queue *q) { unsigned int buffer; /* Call driver-provided cleanup function for each buffer, if provided */ if (q->ops->buf_cleanup) { for (buffer = 0; 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); /* Free videobuf buffers */ for (buffer = 0; buffer < q->num_buffers; ++buffer) { kfree(q->bufs[buffer]); q->bufs[buffer] = NULL; } q->num_buffers = 0; q->memory = 0; return 0; } /** * __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, struct v4l2_buffer *b) { /* 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; } /** * __fill_v4l2_buffer() - fill in a struct v4l2_buffer with information to be * returned to userspace */ static int __fill_v4l2_buffer(struct vb2_buffer *vb, struct v4l2_buffer *b) { struct vb2_queue *q = vb->vb2_queue; int ret = 0; /* Copy back data such as timestamp, input, etc. */ memcpy(b, &vb->v4l2_buf, offsetof(struct v4l2_buffer, m)); b->input = vb->v4l2_buf.input; b->reserved = vb->v4l2_buf.reserved; if (V4L2_TYPE_IS_MULTIPLANAR(q->type)) { ret = __verify_planes_array(vb, b); if (ret) return ret; /* * Fill in plane-related data if userspace provided an array * for it. The memory and size is verified above. */ 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; } b->flags = 0; 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_DEQUEUED: /* nothing */ break; } if (vb->num_planes_mapped == vb->num_planes) b->flags |= V4L2_BUF_FLAG_MAPPED; return ret; } /** * 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; 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]; return __fill_v4l2_buffer(vb, b); } 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; } /** * __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, plane; struct vb2_buffer *vb; for (buffer = 0; buffer < q->num_buffers; ++buffer) { vb = q->bufs[buffer]; for (plane = 0; plane < vb->num_planes; ++plane) { /* * 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 (call_memop(q, plane, num_users, vb->planes[plane].mem_priv) > 1) return true; } } return false; } /** * vb2_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. */ int vb2_reqbufs(struct vb2_queue *q, struct v4l2_requestbuffers *req) { unsigned int num_buffers, num_planes; unsigned long plane_sizes[VIDEO_MAX_PLANES]; int ret = 0; if (req->memory != V4L2_MEMORY_MMAP && req->memory != V4L2_MEMORY_USERPTR) { dprintk(1, "reqbufs: unsupported memory type\n"); return -EINVAL; } if (req->type != q->type) { dprintk(1, "reqbufs: requested type is incorrect\n"); return -EINVAL; } if (q->streaming) { dprintk(1, "reqbufs: streaming active\n"); return -EBUSY; } /* * Make sure all the required memory ops for given memory type * are available. */ if (req->memory == V4L2_MEMORY_MMAP && __verify_mmap_ops(q)) { dprintk(1, "reqbufs: MMAP for current setup unsupported\n"); return -EINVAL; } if (req->memory == V4L2_MEMORY_USERPTR && __verify_userptr_ops(q)) { dprintk(1, "reqbufs: USERPTR for current setup unsupported\n"); return -EINVAL; } if (req->count == 0 || q->num_buffers != 0) { /* * 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; } ret = __vb2_queue_free(q); if (ret != 0) return ret; } /* * Make sure the requested values and current defaults are sane. */ num_buffers = min_t(unsigned int, req->count, VIDEO_MAX_FRAME); memset(plane_sizes, 0, sizeof(plane_sizes)); memset(q->alloc_ctx, 0, sizeof(q->alloc_ctx)); /* * 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, &num_buffers, &num_planes, 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, plane_sizes); if (ret < 0) { dprintk(1, "Memory allocation failed with error: %d\n", ret); return ret; } /* * Check if driver can handle the allocated number of buffers. */ if (ret < num_buffers) { unsigned int orig_num_buffers; orig_num_buffers = num_buffers = ret; ret = call_qop(q, queue_setup, q, &num_buffers, &num_planes, plane_sizes, q->alloc_ctx); if (ret) goto free_mem; if (orig_num_buffers < num_buffers) { ret = -ENOMEM; goto free_mem; } /* * Ok, driver accepted smaller number of buffers. */ ret = num_buffers; } q->memory = req->memory; /* * Return the number of successfully allocated buffers * to the userspace. */ req->count = ret; return 0; free_mem: __vb2_queue_free(q); return ret; } EXPORT_SYMBOL_GPL(vb2_reqbufs); /** * 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) return NULL; return call_memop(q, plane_no, 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) return NULL; return call_memop(q, plane_no, 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; 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, vb->state); /* 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 */ static int __fill_vb2_buffer(struct vb2_buffer *vb, struct v4l2_buffer *b, struct v4l2_plane *v4l2_planes) { unsigned int plane; int ret; if (V4L2_TYPE_IS_MULTIPLANAR(b->type)) { /* * Verify that the userspace gave us a valid array for * plane information. */ ret = __verify_planes_array(vb, b); if (ret) return ret; /* 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; } } } 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; if (b->memory == V4L2_MEMORY_USERPTR) { v4l2_planes[0].m.userptr = b->m.userptr; v4l2_planes[0].length = b->length; } } vb->v4l2_buf.field = b->field; vb->v4l2_buf.timestamp = b->timestamp; return 0; } /** * __qbuf_userptr() - handle qbuf of a USERPTR buffer */ static int __qbuf_userptr(struct vb2_buffer *vb, 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 */ ret = __fill_vb2_buffer(vb, b, planes); if (ret) return ret; for (plane = 0; plane < vb->num_planes; ++plane) { /* Skip the plane if already verified */ if (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); /* Release previously acquired memory if present */ if (vb->planes[plane].mem_priv) call_memop(q, plane, put_userptr, vb->planes[plane].mem_priv); vb->planes[plane].mem_priv = NULL; /* Acquire each plane's memory */ if (q->mem_ops->get_userptr) { mem_priv = q->mem_ops->get_userptr(q->alloc_ctx[plane], planes[plane].m.userptr, planes[plane].length, write); if (IS_ERR(mem_priv)) { dprintk(1, "qbuf: failed acquiring userspace " "memory for plane %d\n", plane); ret = PTR_ERR(mem_priv); 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) { call_memop(q, plane, put_userptr, vb->planes[plane - 1].mem_priv); vb->planes[plane - 1].mem_priv = NULL; } return ret; } /** * __qbuf_mmap() - handle qbuf of an MMAP buffer */ static int __qbuf_mmap(struct vb2_buffer *vb, struct v4l2_buffer *b) { return __fill_vb2_buffer(vb, b, vb->v4l2_planes); } /** * __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; vb->state = VB2_BUF_STATE_ACTIVE; atomic_inc(&q->queued_count); q->ops->buf_queue(vb); } /** * 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) 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 vb2_buffer *vb; int ret = 0; if (b->type != q->type) { dprintk(1, "qbuf: invalid buffer type\n"); return -EINVAL; } if (b->index >= q->num_buffers) { dprintk(1, "qbuf: buffer index out of range\n"); return -EINVAL; } vb = q->bufs[b->index]; if (NULL == vb) { /* Should never happen */ dprintk(1, "qbuf: buffer is NULL\n"); return -EINVAL; } if (b->memory != q->memory) { dprintk(1, "qbuf: invalid memory type\n"); return -EINVAL; } if (vb->state != VB2_BUF_STATE_DEQUEUED) { dprintk(1, "qbuf: buffer already in use\n"); return -EINVAL; } if (q->memory == V4L2_MEMORY_MMAP) ret = __qbuf_mmap(vb, b); else if (q->memory == V4L2_MEMORY_USERPTR) ret = __qbuf_userptr(vb, b); else { WARN(1, "Invalid queue type\n"); return -EINVAL; } if (ret) return ret; ret = call_qop(q, buf_prepare, vb); if (ret) { dprintk(1, "qbuf: buffer preparation failed\n"); return ret; } /* * 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); dprintk(1, "qbuf of buffer %d succeeded\n", vb->v4l2_buf.index); return 0; } 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) 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, 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); list_del(&(*vb)->done_entry); spin_unlock_irqrestore(&q->done_lock, flags); return 0; } /** * 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() - 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 (b->type != q->type) { dprintk(1, "dqbuf: invalid buffer type\n"); return -EINVAL; } ret = __vb2_get_done_vb(q, &vb, nonblocking); if (ret < 0) { dprintk(1, "dqbuf: error getting next done buffer\n"); 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); dprintk(1, "dqbuf of buffer %d, with state %d\n", vb->v4l2_buf.index, vb->state); vb->state = VB2_BUF_STATE_DEQUEUED; return 0; } EXPORT_SYMBOL_GPL(vb2_dqbuf); /** * 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) starts streaming and passes any previously queued buffers to the driver * * 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; if (type != q->type) { dprintk(1, "streamon: invalid stream type\n"); return -EINVAL; } if (q->streaming) { dprintk(1, "streamon: already streaming\n"); return -EBUSY; } /* * Cannot start streaming on an OUTPUT device if no buffers have * been queued yet. */ if (V4L2_TYPE_IS_OUTPUT(q->type)) { if (list_empty(&q->queued_list)) { dprintk(1, "streamon: no output buffers queued\n"); return -EINVAL; } } q->streaming = 1; /* * Let driver notice that streaming state has been enabled. */ call_qop(q, start_streaming, q); /* * 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); dprintk(3, "Streamon successful\n"); return 0; } EXPORT_SYMBOL_GPL(vb2_streamon); /** * __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); wake_up_all(&q->done_wq); /* * Reinitialize all buffers for next use. */ for (i = 0; i < q->num_buffers; ++i) q->bufs[i]->state = VB2_BUF_STATE_DEQUEUED; } /** * 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 (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_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_plane *vb_plane; 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; } /* * 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]; vb_plane = &vb->planes[plane]; ret = q->mem_ops->mmap(vb_plane->mem_priv, vma); if (ret) return ret; vb_plane->mapped = 1; vb->num_planes_mapped++; dprintk(3, "Buffer %d, plane %d successfully mapped\n", buffer, plane); return 0; } EXPORT_SYMBOL_GPL(vb2_mmap); /** * 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. * * 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) { unsigned long flags; struct vb2_buffer *vb = NULL; /* * There is nothing to wait for if no buffers have already been queued. */ if (list_empty(&q->queued_list)) return POLLERR; 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)) ? POLLOUT | POLLWRNORM : POLLIN | POLLRDNORM; } return 0; } 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) { BUG_ON(!q); BUG_ON(!q->ops); BUG_ON(!q->mem_ops); BUG_ON(!q->type); BUG_ON(!q->io_modes); BUG_ON(!q->ops->queue_setup); BUG_ON(!q->ops->buf_queue); 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_queue_cancel(q); __vb2_queue_free(q); } EXPORT_SYMBOL_GPL(vb2_queue_release); MODULE_DESCRIPTION("Driver helper framework for Video for Linux 2"); MODULE_AUTHOR("Pawel Osciak, Marek Szyprowski"); MODULE_LICENSE("GPL");