- 根目录:
- drivers
- media
- video
- videobuf2-core.c
/*
* videobuf2-core.c - V4L2 driver helper framework
*
* Copyright (C) 2010 Samsung Electronics
*
* Author: Pawel Osciak <pawel@osciak.com>
* Marek Szyprowski <m.szyprowski@samsung.com>
*
* 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 <linux/err.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mm.h>
#include <linux/poll.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <media/videobuf2-core.h>
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)
#define V4L2_BUFFER_STATE_FLAGS (V4L2_BUF_FLAG_MAPPED | V4L2_BUF_FLAG_QUEUED | \
V4L2_BUF_FLAG_DONE | V4L2_BUF_FLAG_ERROR)
/**
* __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 (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 = 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 void __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;
}
/**
* __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, flags, 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;
}
/*
* Clear any buffer state related flags.
*/
b->flags &= ~V4L2_BUFFER_STATE_FLAGS;
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 (q->fileio) {
dprintk(1, "reqbufs: file io in progress\n");
return -EBUSY;
}
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 || 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);
/*
* 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(plane_sizes, 0, sizeof(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, &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\n");
return -ENOMEM;
}
/*
* 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;
}
/*
* 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;
vb->v4l2_buf.input = b->input;
vb->v4l2_buf.flags = b->flags & ~V4L2_BUFFER_STATE_FLAGS;
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 (q->fileio) {
dprintk(1, "qbuf: file io in progress\n");
return -EBUSY;
}
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 (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, 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;
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;
}
/*
* 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;
}
}
/*
* Let driver notice that streaming state has been enabled.
*/
ret = call_qop(q, start_streaming, q);
if (ret) {
dprintk(1, "streamon: driver refused to start streaming\n");
return ret;
}
q->streaming = 1;
/*
* 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);
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)
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 (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_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);
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.
*
* 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;
unsigned int ret;
struct vb2_buffer *vb = NULL;
/*
* 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)) {
ret = __vb2_init_fileio(q, 1);
if (ret)
return POLLERR;
}
if (V4L2_TYPE_IS_OUTPUT(q->type) && (q->io_modes & VB2_WRITE)) {
ret = __vb2_init_fileio(q, 0);
if (ret)
return POLLERR;
/*
* Write to OUTPUT queue can be done immediately.
*/
return POLLOUT | POLLWRNORM;
}
}
/*
* 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_cleanup_fileio(q);
__vb2_queue_cancel(q);
__vb2_queue_free(q);
}
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) {
fileio->req.count = 0;
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:
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);
MODULE_DESCRIPTION("Driver helper framework for Video for Linux 2");
MODULE_AUTHOR("Pawel Osciak <pawel@osciak.com>, Marek Szyprowski");
MODULE_LICENSE("GPL");