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linux/drivers/media/v4l2-core/videobuf2-core.c
Hans Verkuil 6cf11ee630 [media] vb2: fix vb2_thread_stop race conditions 
The locking scheme inside the vb2 thread is unsafe when stopping the
thread. In particular kthread_stop was called *after* internal data
structures were cleaned up instead of doing that before. In addition,
internal vb2 functions were called after threadio->stop was set to
true and vb2_internal_streamoff was called. This is also not allowed.

All this led to a variety of race conditions and kernel warnings and/or
oopses.

Fixed by moving the kthread_stop call up before the cleanup takes
place, and by checking threadio->stop before calling internal vb2
queuing operations.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Cc: <stable@vger.kernel.org>      # for v3.16 and up
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2015-01-21 21:07:26 -02:00

3514 lines
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/*
* videobuf2-core.c - V4L2 driver helper framework
*
* Copyright (C) 2010 Samsung Electronics
*
* Author: Pawel Osciak <pawel@osciak.com>
* Marek Szyprowski <m.szyprowski@samsung.com>
*
* The vb2_thread implementation was based on code from videobuf-dvb.c:
* (c) 2004 Gerd Knorr <kraxel@bytesex.org> [SUSE Labs]
*
* 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 <linux/freezer.h>
#include <linux/kthread.h>
#include <media/v4l2-dev.h>
#include <media/v4l2-fh.h>
#include <media/v4l2-event.h>
#include <media/v4l2-common.h>
#include <media/videobuf2-core.h>
static int debug;
module_param(debug, int, 0644);
#define dprintk(level, fmt, arg...) \
do { \
if (debug >= level) \
pr_info("vb2: %s: " fmt, __func__, ## arg); \
} while (0)
#ifdef CONFIG_VIDEO_ADV_DEBUG
/*
* If advanced debugging is on, then count how often each op is called
* successfully, which can either be per-buffer or per-queue.
*
* This makes it easy to check that the 'init' and 'cleanup'
* (and variations thereof) stay balanced.
*/
#define log_memop(vb, op) \
dprintk(2, "call_memop(%p, %d, %s)%s\n", \
(vb)->vb2_queue, (vb)->v4l2_buf.index, #op, \
(vb)->vb2_queue->mem_ops->op ? "" : " (nop)")
#define call_memop(vb, op, args...) \
({ \
struct vb2_queue *_q = (vb)->vb2_queue; \
int err; \
\
log_memop(vb, op); \
err = _q->mem_ops->op ? _q->mem_ops->op(args) : 0; \
if (!err) \
(vb)->cnt_mem_ ## op++; \
err; \
})
#define call_ptr_memop(vb, op, args...) \
({ \
struct vb2_queue *_q = (vb)->vb2_queue; \
void *ptr; \
\
log_memop(vb, op); \
ptr = _q->mem_ops->op ? _q->mem_ops->op(args) : NULL; \
if (!IS_ERR_OR_NULL(ptr)) \
(vb)->cnt_mem_ ## op++; \
ptr; \
})
#define call_void_memop(vb, op, args...) \
({ \
struct vb2_queue *_q = (vb)->vb2_queue; \
\
log_memop(vb, op); \
if (_q->mem_ops->op) \
_q->mem_ops->op(args); \
(vb)->cnt_mem_ ## op++; \
})
#define log_qop(q, op) \
dprintk(2, "call_qop(%p, %s)%s\n", q, #op, \
(q)->ops->op ? "" : " (nop)")
#define call_qop(q, op, args...) \
({ \
int err; \
\
log_qop(q, op); \
err = (q)->ops->op ? (q)->ops->op(args) : 0; \
if (!err) \
(q)->cnt_ ## op++; \
err; \
})
#define call_void_qop(q, op, args...) \
({ \
log_qop(q, op); \
if ((q)->ops->op) \
(q)->ops->op(args); \
(q)->cnt_ ## op++; \
})
#define log_vb_qop(vb, op, args...) \
dprintk(2, "call_vb_qop(%p, %d, %s)%s\n", \
(vb)->vb2_queue, (vb)->v4l2_buf.index, #op, \
(vb)->vb2_queue->ops->op ? "" : " (nop)")
#define call_vb_qop(vb, op, args...) \
({ \
int err; \
\
log_vb_qop(vb, op); \
err = (vb)->vb2_queue->ops->op ? \
(vb)->vb2_queue->ops->op(args) : 0; \
if (!err) \
(vb)->cnt_ ## op++; \
err; \
})
#define call_void_vb_qop(vb, op, args...) \
({ \
log_vb_qop(vb, op); \
if ((vb)->vb2_queue->ops->op) \
(vb)->vb2_queue->ops->op(args); \
(vb)->cnt_ ## op++; \
})
#else
#define call_memop(vb, op, args...) \
((vb)->vb2_queue->mem_ops->op ? \
(vb)->vb2_queue->mem_ops->op(args) : 0)
#define call_ptr_memop(vb, op, args...) \
((vb)->vb2_queue->mem_ops->op ? \
(vb)->vb2_queue->mem_ops->op(args) : NULL)
#define call_void_memop(vb, op, args...) \
do { \
if ((vb)->vb2_queue->mem_ops->op) \
(vb)->vb2_queue->mem_ops->op(args); \
} while (0)
#define call_qop(q, op, args...) \
((q)->ops->op ? (q)->ops->op(args) : 0)
#define call_void_qop(q, op, args...) \
do { \
if ((q)->ops->op) \
(q)->ops->op(args); \
} while (0)
#define call_vb_qop(vb, op, args...) \
((vb)->vb2_queue->ops->op ? (vb)->vb2_queue->ops->op(args) : 0)
#define call_void_vb_qop(vb, op, args...) \
do { \
if ((vb)->vb2_queue->ops->op) \
(vb)->vb2_queue->ops->op(args); \
} while (0)
#endif
/* Flags that are set by the vb2 core */
#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)
/* Output buffer flags that should be passed on to the driver */
#define V4L2_BUFFER_OUT_FLAGS (V4L2_BUF_FLAG_PFRAME | V4L2_BUF_FLAG_BFRAME | \
V4L2_BUF_FLAG_KEYFRAME | V4L2_BUF_FLAG_TIMECODE)
static void __vb2_queue_cancel(struct vb2_queue *q);
/**
* __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;
enum dma_data_direction dma_dir =
V4L2_TYPE_IS_OUTPUT(q->type) ? DMA_TO_DEVICE : DMA_FROM_DEVICE;
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_ptr_memop(vb, alloc, q->alloc_ctx[plane],
size, dma_dir, 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_void_memop(vb, 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)
{
unsigned int plane;
for (plane = 0; plane < vb->num_planes; ++plane) {
call_void_memop(vb, 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)
{
unsigned int plane;
for (plane = 0; plane < vb->num_planes; ++plane) {
if (vb->planes[plane].mem_priv)
call_void_memop(vb, 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_buffer *vb, struct vb2_plane *p)
{
if (!p->mem_priv)
return;
if (p->dbuf_mapped)
call_void_memop(vb, unmap_dmabuf, p->mem_priv);
call_void_memop(vb, 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)
{
unsigned int plane;
for (plane = 0; plane < vb->num_planes; ++plane)
__vb2_plane_dmabuf_put(vb, &vb->planes[plane]);
}
/**
* __setup_lengths() - setup initial lengths for every plane in
* every buffer on the queue
*/
static void __setup_lengths(struct vb2_queue *q, unsigned int n)
{
unsigned int buffer, plane;
struct vb2_buffer *vb;
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];
}
}
/**
* __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].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_vb_qop(vb, 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_lengths(q, buffer);
if (memory == V4L2_MEMORY_MMAP)
__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 int __vb2_queue_free(struct vb2_queue *q, unsigned int buffers)
{
unsigned int buffer;
/*
* Sanity check: when preparing a buffer the queue lock is released for
* a short while (see __buf_prepare for the details), which would allow
* a race with a reqbufs which can call this function. Removing the
* buffers from underneath __buf_prepare is obviously a bad idea, so we
* check if any of the buffers is in the state PREPARING, and if so we
* just return -EAGAIN.
*/
for (buffer = q->num_buffers - buffers; buffer < q->num_buffers;
++buffer) {
if (q->bufs[buffer] == NULL)
continue;
if (q->bufs[buffer]->state == VB2_BUF_STATE_PREPARING) {
dprintk(1, "preparing buffers, cannot free\n");
return -EAGAIN;
}
}
/* Call driver-provided cleanup function for each buffer, if provided */
for (buffer = q->num_buffers - buffers; buffer < q->num_buffers;
++buffer) {
struct vb2_buffer *vb = q->bufs[buffer];
if (vb && vb->planes[0].mem_priv)
call_void_vb_qop(vb, buf_cleanup, vb);
}
/* Release video buffer memory */
__vb2_free_mem(q, buffers);
#ifdef CONFIG_VIDEO_ADV_DEBUG
/*
* Check that all the calls were balances during the life-time of this
* queue. If not (or if the debug level is 1 or up), then dump the
* counters to the kernel log.
*/
if (q->num_buffers) {
bool unbalanced = q->cnt_start_streaming != q->cnt_stop_streaming ||
q->cnt_wait_prepare != q->cnt_wait_finish;
if (unbalanced || debug) {
pr_info("vb2: counters for queue %p:%s\n", q,
unbalanced ? " UNBALANCED!" : "");
pr_info("vb2: setup: %u start_streaming: %u stop_streaming: %u\n",
q->cnt_queue_setup, q->cnt_start_streaming,
q->cnt_stop_streaming);
pr_info("vb2: wait_prepare: %u wait_finish: %u\n",
q->cnt_wait_prepare, q->cnt_wait_finish);
}
q->cnt_queue_setup = 0;
q->cnt_wait_prepare = 0;
q->cnt_wait_finish = 0;
q->cnt_start_streaming = 0;
q->cnt_stop_streaming = 0;
}
for (buffer = 0; buffer < q->num_buffers; ++buffer) {
struct vb2_buffer *vb = q->bufs[buffer];
bool unbalanced = vb->cnt_mem_alloc != vb->cnt_mem_put ||
vb->cnt_mem_prepare != vb->cnt_mem_finish ||
vb->cnt_mem_get_userptr != vb->cnt_mem_put_userptr ||
vb->cnt_mem_attach_dmabuf != vb->cnt_mem_detach_dmabuf ||
vb->cnt_mem_map_dmabuf != vb->cnt_mem_unmap_dmabuf ||
vb->cnt_buf_queue != vb->cnt_buf_done ||
vb->cnt_buf_prepare != vb->cnt_buf_finish ||
vb->cnt_buf_init != vb->cnt_buf_cleanup;
if (unbalanced || debug) {
pr_info("vb2: counters for queue %p, buffer %d:%s\n",
q, buffer, unbalanced ? " UNBALANCED!" : "");
pr_info("vb2: buf_init: %u buf_cleanup: %u buf_prepare: %u buf_finish: %u\n",
vb->cnt_buf_init, vb->cnt_buf_cleanup,
vb->cnt_buf_prepare, vb->cnt_buf_finish);
pr_info("vb2: buf_queue: %u buf_done: %u\n",
vb->cnt_buf_queue, vb->cnt_buf_done);
pr_info("vb2: alloc: %u put: %u prepare: %u finish: %u mmap: %u\n",
vb->cnt_mem_alloc, vb->cnt_mem_put,
vb->cnt_mem_prepare, vb->cnt_mem_finish,
vb->cnt_mem_mmap);
pr_info("vb2: get_userptr: %u put_userptr: %u\n",
vb->cnt_mem_get_userptr, vb->cnt_mem_put_userptr);
pr_info("vb2: attach_dmabuf: %u detach_dmabuf: %u map_dmabuf: %u unmap_dmabuf: %u\n",
vb->cnt_mem_attach_dmabuf, vb->cnt_mem_detach_dmabuf,
vb->cnt_mem_map_dmabuf, vb->cnt_mem_unmap_dmabuf);
pr_info("vb2: get_dmabuf: %u num_users: %u vaddr: %u cookie: %u\n",
vb->cnt_mem_get_dmabuf,
vb->cnt_mem_num_users,
vb->cnt_mem_vaddr,
vb->cnt_mem_cookie);
}
}
#endif
/* 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);
}
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, 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;
}
/**
* __verify_length() - Verify that the bytesused value for each plane fits in
* the plane length and that the data offset doesn't exceed the bytesused value.
*/
static int __verify_length(struct vb2_buffer *vb, const struct v4l2_buffer *b)
{
unsigned int length;
unsigned int bytesused;
unsigned int plane;
if (!V4L2_TYPE_IS_OUTPUT(b->type))
return 0;
if (V4L2_TYPE_IS_MULTIPLANAR(b->type)) {
for (plane = 0; plane < vb->num_planes; ++plane) {
length = (b->memory == V4L2_MEMORY_USERPTR ||
b->memory == V4L2_MEMORY_DMABUF)
? b->m.planes[plane].length
: vb->v4l2_planes[plane].length;
bytesused = b->m.planes[plane].bytesused
? b->m.planes[plane].bytesused : length;
if (b->m.planes[plane].bytesused > length)
return -EINVAL;
if (b->m.planes[plane].data_offset > 0 &&
b->m.planes[plane].data_offset >= bytesused)
return -EINVAL;
}
} else {
length = (b->memory == V4L2_MEMORY_USERPTR)
? b->length : vb->v4l2_planes[0].length;
bytesused = b->bytesused ? b->bytesused : length;
if (b->bytesused > 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(vb, 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_flags & V4L2_BUF_FLAG_TIMESTAMP_MASK;
if ((q->timestamp_flags & V4L2_BUF_FLAG_TIMESTAMP_MASK) !=
V4L2_BUF_FLAG_TIMESTAMP_COPY) {
/*
* For non-COPY timestamps, drop timestamp source bits
* and obtain the timestamp source from the queue.
*/
b->flags &= ~V4L2_BUF_FLAG_TSTAMP_SRC_MASK;
b->flags |= q->timestamp_flags & V4L2_BUF_FLAG_TSTAMP_SRC_MASK;
}
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_PREPARING:
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, "wrong buffer type\n");
return -EINVAL;
}
if (b->index >= q->num_buffers) {
dprintk(1, "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, "unsupported memory type\n");
return -EINVAL;
}
if (type != q->type) {
dprintk(1, "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, "MMAP for current setup unsupported\n");
return -EINVAL;
}
if (memory == V4L2_MEMORY_USERPTR && __verify_userptr_ops(q)) {
dprintk(1, "USERPTR for current setup unsupported\n");
return -EINVAL;
}
if (memory == V4L2_MEMORY_DMABUF && __verify_dmabuf_ops(q)) {
dprintk(1, "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 (vb2_fileio_is_active(q)) {
dprintk(1, "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, "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.
*/
mutex_lock(&q->mmap_lock);
if (q->memory == V4L2_MEMORY_MMAP && __buffers_in_use(q)) {
mutex_unlock(&q->mmap_lock);
dprintk(1, "memory in use, cannot free\n");
return -EBUSY;
}
/*
* Call queue_cancel to clean up any buffers in the PREPARED or
* QUEUED state which is possible if buffers were prepared or
* queued without ever calling STREAMON.
*/
__vb2_queue_cancel(q);
ret = __vb2_queue_free(q, q->num_buffers);
mutex_unlock(&q->mmap_lock);
if (ret)
return ret;
/*
* 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);
num_buffers = max_t(unsigned int, num_buffers, q->min_buffers_needed);
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 */
allocated_buffers = __vb2_queue_alloc(q, req->memory, num_buffers, num_planes);
if (allocated_buffers == 0) {
dprintk(1, "memory allocation failed\n");
return -ENOMEM;
}
/*
* There is no point in continuing if we can't allocate the minimum
* number of buffers needed by this vb2_queue.
*/
if (allocated_buffers < q->min_buffers_needed)
ret = -ENOMEM;
/*
* Check if driver can handle the allocated number of buffers.
*/
if (!ret && 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
*/
}
mutex_lock(&q->mmap_lock);
q->num_buffers = allocated_buffers;
if (ret < 0) {
/*
* Note: __vb2_queue_free() will subtract 'allocated_buffers'
* from q->num_buffers.
*/
__vb2_queue_free(q, allocated_buffers);
mutex_unlock(&q->mmap_lock);
return ret;
}
mutex_unlock(&q->mmap_lock);
/*
* Return the number of successfully allocated buffers
* to the userspace.
*/
req->count = allocated_buffers;
q->waiting_for_buffers = !V4L2_TYPE_IS_OUTPUT(q->type);
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, "maximum number of buffers already allocated\n");
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;
q->waiting_for_buffers = !V4L2_TYPE_IS_OUTPUT(q->type);
}
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 */
allocated_buffers = __vb2_queue_alloc(q, create->memory, num_buffers,
num_planes);
if (allocated_buffers == 0) {
dprintk(1, "memory allocation failed\n");
return -ENOMEM;
}
/*
* Check if driver can handle the so far allocated number of buffers.
*/
if (allocated_buffers < num_buffers) {
num_buffers = allocated_buffers;
/*
* 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
*/
}
mutex_lock(&q->mmap_lock);
q->num_buffers += allocated_buffers;
if (ret < 0) {
/*
* Note: __vb2_queue_free() will subtract 'allocated_buffers'
* from q->num_buffers.
*/
__vb2_queue_free(q, allocated_buffers);
mutex_unlock(&q->mmap_lock);
return -ENOMEM;
}
mutex_unlock(&q->mmap_lock);
/*
* 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)
{
if (plane_no > vb->num_planes || !vb->planes[plane_no].mem_priv)
return NULL;
return call_ptr_memop(vb, 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)
{
if (plane_no >= vb->num_planes || !vb->planes[plane_no].mem_priv)
return NULL;
return call_ptr_memop(vb, 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.
* If start_streaming fails then it should return buffers with state
* VB2_BUF_STATE_QUEUED to put them back into the queue.
*
* 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.
*
* While streaming a buffer can only be returned in state DONE or ERROR.
* The start_streaming op can also return them in case the DMA engine cannot
* be started for some reason. In that case the buffers should be returned with
* state QUEUED.
*/
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 (WARN_ON(vb->state != VB2_BUF_STATE_ACTIVE))
return;
if (WARN_ON(state != VB2_BUF_STATE_DONE &&
state != VB2_BUF_STATE_ERROR &&
state != VB2_BUF_STATE_QUEUED))
state = VB2_BUF_STATE_ERROR;
#ifdef CONFIG_VIDEO_ADV_DEBUG
/*
* Although this is not a callback, it still does have to balance
* with the buf_queue op. So update this counter manually.
*/
vb->cnt_buf_done++;
#endif
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_void_memop(vb, finish, vb->planes[plane].mem_priv);
/* Add the buffer to the done buffers list */
spin_lock_irqsave(&q->done_lock, flags);
vb->state = state;
if (state != VB2_BUF_STATE_QUEUED)
list_add_tail(&vb->done_entry, &q->done_list);
atomic_dec(&q->owned_by_drv_count);
spin_unlock_irqrestore(&q->done_lock, flags);
if (state == VB2_BUF_STATE_QUEUED)
return;
/* Inform any processes that may be waiting for buffers */
wake_up(&q->done_wq);
}
EXPORT_SYMBOL_GPL(vb2_buffer_done);
/**
* vb2_discard_done() - discard all buffers marked as DONE
* @q: videobuf2 queue
*
* This function is intended to be used with suspend/resume operations. It
* discards all 'done' buffers as they would be too old to be requested after
* resume.
*
* Drivers must stop the hardware and synchronize with interrupt handlers and/or
* delayed works before calling this function to make sure no buffer will be
* touched by the driver and/or hardware.
*/
void vb2_discard_done(struct vb2_queue *q)
{
struct vb2_buffer *vb;
unsigned long flags;
spin_lock_irqsave(&q->done_lock, flags);
list_for_each_entry(vb, &q->done_list, done_entry)
vb->state = VB2_BUF_STATE_ERROR;
spin_unlock_irqrestore(&q->done_lock, flags);
}
EXPORT_SYMBOL_GPL(vb2_discard_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)) {
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;
}
}
/* 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.
*
* If bytesused == 0 for the output buffer, then fall
* back to the full buffer size. In that case
* userspace clearly never bothered to set it and
* it's a safe assumption that they really meant to
* use the full plane sizes.
*/
for (plane = 0; plane < vb->num_planes; ++plane) {
struct v4l2_plane *pdst = &v4l2_planes[plane];
struct v4l2_plane *psrc = &b->m.planes[plane];
pdst->bytesused = psrc->bytesused ?
psrc->bytesused : pdst->length;
pdst->data_offset = psrc->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 bytesused == 0 for the output buffer, then fall back
* to the full buffer size as that's a sensible default.
*/
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;
}
if (V4L2_TYPE_IS_OUTPUT(b->type))
v4l2_planes[0].bytesused = b->bytesused ?
b->bytesused : v4l2_planes[0].length;
else
v4l2_planes[0].bytesused = 0;
}
/* Zero flags that the vb2 core handles */
vb->v4l2_buf.flags = b->flags & ~V4L2_BUFFER_MASK_FLAGS;
if ((vb->vb2_queue->timestamp_flags & V4L2_BUF_FLAG_TIMESTAMP_MASK) !=
V4L2_BUF_FLAG_TIMESTAMP_COPY || !V4L2_TYPE_IS_OUTPUT(b->type)) {
/*
* Non-COPY timestamps and non-OUTPUT queues will get
* their timestamp and timestamp source flags from the
* queue.
*/
vb->v4l2_buf.flags &= ~V4L2_BUF_FLAG_TSTAMP_SRC_MASK;
}
if (V4L2_TYPE_IS_OUTPUT(b->type)) {
/*
* For output buffers mask out the timecode flag:
* this will be handled later in vb2_internal_qbuf().
* The 'field' is valid metadata for this output buffer
* and so that needs to be copied here.
*/
vb->v4l2_buf.flags &= ~V4L2_BUF_FLAG_TIMECODE;
vb->v4l2_buf.field = b->field;
} else {
/* Zero any output buffer flags as this is a capture buffer */
vb->v4l2_buf.flags &= ~V4L2_BUFFER_OUT_FLAGS;
}
}
/**
* __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 call_vb_qop(vb, buf_prepare, vb);
}
/**
* __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;
enum dma_data_direction dma_dir =
V4L2_TYPE_IS_OUTPUT(q->type) ? DMA_TO_DEVICE : DMA_FROM_DEVICE;
bool reacquired = vb->planes[0].mem_priv == NULL;
memset(planes, 0, sizeof(planes[0]) * vb->num_planes);
/* 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, "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]) {
dprintk(1, "provided buffer size %u is less than "
"setup size %u for plane %d\n",
planes[plane].length,
q->plane_sizes[plane], plane);
ret = -EINVAL;
goto err;
}
/* Release previously acquired memory if present */
if (vb->planes[plane].mem_priv) {
if (!reacquired) {
reacquired = true;
call_void_vb_qop(vb, buf_cleanup, vb);
}
call_void_memop(vb, put_userptr, vb->planes[plane].mem_priv);
}
vb->planes[plane].mem_priv = NULL;
memset(&vb->v4l2_planes[plane], 0, sizeof(struct v4l2_plane));
/* Acquire each plane's memory */
mem_priv = call_ptr_memop(vb, get_userptr, q->alloc_ctx[plane],
planes[plane].m.userptr,
planes[plane].length, dma_dir);
if (IS_ERR_OR_NULL(mem_priv)) {
dprintk(1, "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;
}
/*
* 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];
if (reacquired) {
/*
* One or more planes changed, so we must call buf_init to do
* the driver-specific initialization on the newly acquired
* buffer, if provided.
*/
ret = call_vb_qop(vb, buf_init, vb);
if (ret) {
dprintk(1, "buffer initialization failed\n");
goto err;
}
}
ret = call_vb_qop(vb, buf_prepare, vb);
if (ret) {
dprintk(1, "buffer preparation failed\n");
call_void_vb_qop(vb, buf_cleanup, vb);
goto err;
}
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_void_memop(vb, 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_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;
enum dma_data_direction dma_dir =
V4L2_TYPE_IS_OUTPUT(q->type) ? DMA_TO_DEVICE : DMA_FROM_DEVICE;
bool reacquired = vb->planes[0].mem_priv == NULL;
memset(planes, 0, sizeof(planes[0]) * vb->num_planes);
/* 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, "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 < q->plane_sizes[plane]) {
dprintk(1, "invalid dmabuf length for plane %d\n",
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, "buffer for plane %d changed\n", plane);
if (!reacquired) {
reacquired = true;
call_void_vb_qop(vb, buf_cleanup, vb);
}
/* Release previously acquired memory if present */
__vb2_plane_dmabuf_put(vb, &vb->planes[plane]);
memset(&vb->v4l2_planes[plane], 0, sizeof(struct v4l2_plane));
/* Acquire each plane's memory */
mem_priv = call_ptr_memop(vb, attach_dmabuf, q->alloc_ctx[plane],
dbuf, planes[plane].length, dma_dir);
if (IS_ERR(mem_priv)) {
dprintk(1, "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(vb, map_dmabuf, vb->planes[plane].mem_priv);
if (ret) {
dprintk(1, "failed to map dmabuf for plane %d\n",
plane);
goto err;
}
vb->planes[plane].dbuf_mapped = 1;
}
/*
* 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];
if (reacquired) {
/*
* Call driver-specific initialization on the newly acquired buffer,
* if provided.
*/
ret = call_vb_qop(vb, buf_init, vb);
if (ret) {
dprintk(1, "buffer initialization failed\n");
goto err;
}
}
ret = call_vb_qop(vb, buf_prepare, vb);
if (ret) {
dprintk(1, "buffer preparation failed\n");
call_void_vb_qop(vb, buf_cleanup, vb);
goto err;
}
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->owned_by_drv_count);
/* sync buffers */
for (plane = 0; plane < vb->num_planes; ++plane)
call_void_memop(vb, prepare, vb->planes[plane].mem_priv);
call_void_vb_qop(vb, 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;
ret = __verify_length(vb, b);
if (ret < 0) {
dprintk(1, "plane parameters verification failed: %d\n", ret);
return ret;
}
if (b->field == V4L2_FIELD_ALTERNATE && V4L2_TYPE_IS_OUTPUT(q->type)) {
/*
* If the format's field is ALTERNATE, then the buffer's field
* should be either TOP or BOTTOM, not ALTERNATE since that
* makes no sense. The driver has to know whether the
* buffer represents a top or a bottom field in order to
* program any DMA correctly. Using ALTERNATE is wrong, since
* that just says that it is either a top or a bottom field,
* but not which of the two it is.
*/
dprintk(1, "the field is incorrectly set to ALTERNATE for an output buffer\n");
return -EINVAL;
}
if (q->error) {
dprintk(1, "fatal error occurred on queue\n");
return -EIO;
}
vb->state = VB2_BUF_STATE_PREPARING;
vb->v4l2_buf.timestamp.tv_sec = 0;
vb->v4l2_buf.timestamp.tv_usec = 0;
vb->v4l2_buf.sequence = 0;
switch (q->memory) {
case V4L2_MEMORY_MMAP:
ret = __qbuf_mmap(vb, b);
break;
case V4L2_MEMORY_USERPTR:
down_read(&current->mm->mmap_sem);
ret = __qbuf_userptr(vb, b);
up_read(&current->mm->mmap_sem);
break;
case V4L2_MEMORY_DMABUF:
ret = __qbuf_dmabuf(vb, b);
break;
default:
WARN(1, "Invalid queue type\n");
ret = -EINVAL;
}
if (ret)
dprintk(1, "buffer preparation failed: %d\n", ret);
vb->state = ret ? VB2_BUF_STATE_DEQUEUED : VB2_BUF_STATE_PREPARED;
return ret;
}
static int vb2_queue_or_prepare_buf(struct vb2_queue *q, struct v4l2_buffer *b,
const char *opname)
{
if (b->type != q->type) {
dprintk(1, "%s: invalid buffer type\n", opname);
return -EINVAL;
}
if (b->index >= q->num_buffers) {
dprintk(1, "%s: buffer index out of range\n", opname);
return -EINVAL;
}
if (q->bufs[b->index] == NULL) {
/* Should never happen */
dprintk(1, "%s: buffer is NULL\n", opname);
return -EINVAL;
}
if (b->memory != q->memory) {
dprintk(1, "%s: invalid memory type\n", opname);
return -EINVAL;
}
return __verify_planes_array(q->bufs[b->index], b);
}
/**
* 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 (vb2_fileio_is_active(q)) {
dprintk(1, "file io in progress\n");
return -EBUSY;
}
ret = vb2_queue_or_prepare_buf(q, b, "prepare_buf");
if (ret)
return ret;
vb = q->bufs[b->index];
if (vb->state != VB2_BUF_STATE_DEQUEUED) {
dprintk(1, "invalid buffer state %d\n",
vb->state);
return -EINVAL;
}
ret = __buf_prepare(vb, b);
if (!ret) {
/* Fill buffer information for the userspace */
__fill_v4l2_buffer(vb, b);
dprintk(1, "prepare of buffer %d succeeded\n", vb->v4l2_buf.index);
}
return ret;
}
EXPORT_SYMBOL_GPL(vb2_prepare_buf);
/**
* vb2_start_streaming() - Attempt to start streaming.
* @q: videobuf2 queue
*
* Attempt to start streaming. When this function is called there must be
* at least q->min_buffers_needed buffers queued up (i.e. the minimum
* number of buffers required for the DMA engine to function). If the
* @start_streaming op fails it is supposed to return all the driver-owned
* buffers back to vb2 in state QUEUED. Check if that happened and if
* not warn and reclaim them forcefully.
*/
static int vb2_start_streaming(struct vb2_queue *q)
{
struct vb2_buffer *vb;
int ret;
/*
* 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);
/* Tell the driver to start streaming */
q->start_streaming_called = 1;
ret = call_qop(q, start_streaming, q,
atomic_read(&q->owned_by_drv_count));
if (!ret)
return 0;
q->start_streaming_called = 0;
dprintk(1, "driver refused to start streaming\n");
/*
* If you see this warning, then the driver isn't cleaning up properly
* after a failed start_streaming(). See the start_streaming()
* documentation in videobuf2-core.h for more information how buffers
* should be returned to vb2 in start_streaming().
*/
if (WARN_ON(atomic_read(&q->owned_by_drv_count))) {
unsigned i;
/*
* Forcefully reclaim buffers if the driver did not
* correctly return them to vb2.
*/
for (i = 0; i < q->num_buffers; ++i) {
vb = q->bufs[i];
if (vb->state == VB2_BUF_STATE_ACTIVE)
vb2_buffer_done(vb, VB2_BUF_STATE_QUEUED);
}
/* Must be zero now */
WARN_ON(atomic_read(&q->owned_by_drv_count));
}
/*
* If done_list is not empty, then start_streaming() didn't call
* vb2_buffer_done(vb, VB2_BUF_STATE_QUEUED) but STATE_ERROR or
* STATE_DONE.
*/
WARN_ON(!list_empty(&q->done_list));
return ret;
}
static int vb2_internal_qbuf(struct vb2_queue *q, struct v4l2_buffer *b)
{
int ret = vb2_queue_or_prepare_buf(q, b, "qbuf");
struct vb2_buffer *vb;
if (ret)
return ret;
vb = q->bufs[b->index];
switch (vb->state) {
case VB2_BUF_STATE_DEQUEUED:
ret = __buf_prepare(vb, b);
if (ret)
return ret;
break;
case VB2_BUF_STATE_PREPARED:
break;
case VB2_BUF_STATE_PREPARING:
dprintk(1, "buffer still being prepared\n");
return -EINVAL;
default:
dprintk(1, "invalid buffer state %d\n", vb->state);
return -EINVAL;
}
/*
* 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);
q->queued_count++;
q->waiting_for_buffers = false;
vb->state = VB2_BUF_STATE_QUEUED;
if (V4L2_TYPE_IS_OUTPUT(q->type)) {
/*
* For output buffers copy the timestamp if needed,
* and the timecode field and flag if needed.
*/
if ((q->timestamp_flags & V4L2_BUF_FLAG_TIMESTAMP_MASK) ==
V4L2_BUF_FLAG_TIMESTAMP_COPY)
vb->v4l2_buf.timestamp = b->timestamp;
vb->v4l2_buf.flags |= b->flags & V4L2_BUF_FLAG_TIMECODE;
if (b->flags & V4L2_BUF_FLAG_TIMECODE)
vb->v4l2_buf.timecode = b->timecode;
}
/*
* If already streaming, give the buffer to driver for processing.
* If not, the buffer will be given to driver on next streamon.
*/
if (q->start_streaming_called)
__enqueue_in_driver(vb);
/* Fill buffer information for the userspace */
__fill_v4l2_buffer(vb, b);
/*
* If streamon has been called, and we haven't yet called
* start_streaming() since not enough buffers were queued, and
* we now have reached the minimum number of queued buffers,
* then we can finally call start_streaming().
*/
if (q->streaming && !q->start_streaming_called &&
q->queued_count >= q->min_buffers_needed) {
ret = vb2_start_streaming(q);
if (ret)
return ret;
}
dprintk(1, "qbuf of buffer %d succeeded\n", vb->v4l2_buf.index);
return 0;
}
/**
* 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)
{
if (vb2_fileio_is_active(q)) {
dprintk(1, "file io in progress\n");
return -EBUSY;
}
return vb2_internal_qbuf(q, b);
}
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 (q->error) {
dprintk(1, "Queue in error state, will not wait for buffers\n");
return -EIO;
}
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_void_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 ||
q->error);
/*
* We need to reevaluate both conditions again after reacquiring
* the locks or return an error if one occurred.
*/
call_void_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;
}
if (q->start_streaming_called)
wait_event(q->done_wq, !atomic_read(&q->owned_by_drv_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_void_memop(vb, unmap_dmabuf, vb->planes[i].mem_priv);
vb->planes[i].dbuf_mapped = 0;
}
}
static int vb2_internal_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, "invalid buffer type\n");
return -EINVAL;
}
ret = __vb2_get_done_vb(q, &vb, b, nonblocking);
if (ret < 0)
return ret;
switch (vb->state) {
case VB2_BUF_STATE_DONE:
dprintk(3, "returning done buffer\n");
break;
case VB2_BUF_STATE_ERROR:
dprintk(3, "returning done buffer with errors\n");
break;
default:
dprintk(1, "invalid buffer state\n");
return -EINVAL;
}
call_void_vb_qop(vb, buf_finish, vb);
/* Fill buffer information for the userspace */
__fill_v4l2_buffer(vb, b);
/* Remove from videobuf queue */
list_del(&vb->queued_entry);
q->queued_count--;
/* 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;
}
/**
* 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)
{
if (vb2_fileio_is_active(q)) {
dprintk(1, "file io in progress\n");
return -EBUSY;
}
return vb2_internal_dqbuf(q, b, nonblocking);
}
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->start_streaming_called)
call_void_qop(q, stop_streaming, q);
/*
* If you see this warning, then the driver isn't cleaning up properly
* in stop_streaming(). See the stop_streaming() documentation in
* videobuf2-core.h for more information how buffers should be returned
* to vb2 in stop_streaming().
*/
if (WARN_ON(atomic_read(&q->owned_by_drv_count))) {
for (i = 0; i < q->num_buffers; ++i)
if (q->bufs[i]->state == VB2_BUF_STATE_ACTIVE)
vb2_buffer_done(q->bufs[i], VB2_BUF_STATE_ERROR);
/* Must be zero now */
WARN_ON(atomic_read(&q->owned_by_drv_count));
}
q->streaming = 0;
q->start_streaming_called = 0;
q->queued_count = 0;
q->error = 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->owned_by_drv_count, 0);
wake_up_all(&q->done_wq);
/*
* Reinitialize all buffers for next use.
* Make sure to call buf_finish for any queued buffers. Normally
* that's done in dqbuf, but that's not going to happen when we
* cancel the whole queue. Note: this code belongs here, not in
* __vb2_dqbuf() since in vb2_internal_dqbuf() there is a critical
* call to __fill_v4l2_buffer() after buf_finish(). That order can't
* be changed, so we can't move the buf_finish() to __vb2_dqbuf().
*/
for (i = 0; i < q->num_buffers; ++i) {
struct vb2_buffer *vb = q->bufs[i];
if (vb->state != VB2_BUF_STATE_DEQUEUED) {
vb->state = VB2_BUF_STATE_PREPARED;
call_void_vb_qop(vb, buf_finish, vb);
}
__vb2_dqbuf(vb);
}
}
static int vb2_internal_streamon(struct vb2_queue *q, enum v4l2_buf_type type)
{
int ret;
if (type != q->type) {
dprintk(1, "invalid stream type\n");
return -EINVAL;
}
if (q->streaming) {
dprintk(3, "already streaming\n");
return 0;
}
if (!q->num_buffers) {
dprintk(1, "no buffers have been allocated\n");
return -EINVAL;
}
if (q->num_buffers < q->min_buffers_needed) {
dprintk(1, "need at least %u allocated buffers\n",
q->min_buffers_needed);
return -EINVAL;
}
/*
* Tell driver to start streaming provided sufficient buffers
* are available.
*/
if (q->queued_count >= q->min_buffers_needed) {
ret = vb2_start_streaming(q);
if (ret) {
__vb2_queue_cancel(q);
return ret;
}
}
q->streaming = 1;
dprintk(3, "successful\n");
return 0;
}
/**
* vb2_queue_error() - signal a fatal error on the queue
* @q: videobuf2 queue
*
* Flag that a fatal unrecoverable error has occurred and wake up all processes
* waiting on the queue. Polling will now set POLLERR and queuing and dequeuing
* buffers will return -EIO.
*
* The error flag will be cleared when cancelling the queue, either from
* vb2_streamoff or vb2_queue_release. Drivers should thus not call this
* function before starting the stream, otherwise the error flag will remain set
* until the queue is released when closing the device node.
*/
void vb2_queue_error(struct vb2_queue *q)
{
q->error = 1;
wake_up_all(&q->done_wq);
}
EXPORT_SYMBOL_GPL(vb2_queue_error);
/**
* 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)
{
if (vb2_fileio_is_active(q)) {
dprintk(1, "file io in progress\n");
return -EBUSY;
}
return vb2_internal_streamon(q, type);
}
EXPORT_SYMBOL_GPL(vb2_streamon);
static int vb2_internal_streamoff(struct vb2_queue *q, enum v4l2_buf_type type)
{
if (type != q->type) {
dprintk(1, "invalid stream type\n");
return -EINVAL;
}
/*
* Cancel will pause streaming and remove all buffers from the driver
* and videobuf, effectively returning control over them to userspace.
*
* Note that we do this even if q->streaming == 0: if you prepare or
* queue buffers, and then call streamoff without ever having called
* streamon, you would still expect those buffers to be returned to
* their normal dequeued state.
*/
__vb2_queue_cancel(q);
q->waiting_for_buffers = !V4L2_TYPE_IS_OUTPUT(q->type);
dprintk(3, "successful\n");
return 0;
}
/**
* 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 (vb2_fileio_is_active(q)) {
dprintk(1, "file io in progress\n");
return -EBUSY;
}
return vb2_internal_streamoff(q, type);
}
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 | O_ACCMODE)) {
dprintk(1, "queue does support only O_CLOEXEC and access mode flags\n");
return -EINVAL;
}
if (eb->type != q->type) {
dprintk(1, "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;
}
if (vb2_fileio_is_active(q)) {
dprintk(1, "expbuf: file io in progress\n");
return -EBUSY;
}
vb_plane = &vb->planes[eb->plane];
dbuf = call_ptr_memop(vb, get_dmabuf, vb_plane->mem_priv, eb->flags & O_ACCMODE);
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 & ~O_ACCMODE);
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 = 0, plane = 0;
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;
}
}
if (vb2_fileio_is_active(q)) {
dprintk(1, "mmap: file io in progress\n");
return -EBUSY;
}
/*
* 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;
}
mutex_lock(&q->mmap_lock);
ret = call_memop(vb, mmap, vb->planes[plane].mem_priv, vma);
mutex_unlock(&q->mmap_lock);
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;
void *vaddr;
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];
vaddr = vb2_plane_vaddr(vb, plane);
return vaddr ? (unsigned long)vaddr : -EINVAL;
}
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 && !vb2_fileio_is_active(q)) {
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 the queue isn't streaming, or if the
* error flag is set.
*/
if (!vb2_is_streaming(q) || q->error)
return res | POLLERR;
/*
* For compatibility with vb1: if QBUF hasn't been called yet, then
* return POLLERR as well. This only affects capture queues, output
* queues will always initialize waiting_for_buffers to false.
*/
if (q->waiting_for_buffers)
return res | POLLERR;
/*
* For output streams you can write as long as there are fewer buffers
* queued than there are buffers available.
*/
if (V4L2_TYPE_IS_OUTPUT(q->type) && q->queued_count < q->num_buffers)
return res | POLLOUT | POLLWRNORM;
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_flags &
~(V4L2_BUF_FLAG_TIMESTAMP_MASK |
V4L2_BUF_FLAG_TSTAMP_SRC_MASK)))
return -EINVAL;
/* Warn that the driver should choose an appropriate timestamp type */
WARN_ON((q->timestamp_flags & V4L2_BUF_FLAG_TIMESTAMP_MASK) ==
V4L2_BUF_FLAG_TIMESTAMP_UNKNOWN);
INIT_LIST_HEAD(&q->queued_list);
INIT_LIST_HEAD(&q->done_list);
spin_lock_init(&q->done_lock);
mutex_init(&q->mmap_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);
mutex_lock(&q->mmap_lock);
__vb2_queue_free(q, q->num_buffers);
mutex_unlock(&q->mmap_lock);
}
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
*
* @cur_index: the index of the buffer currently being read from or
* written to. If equal to q->num_buffers then a new buffer
* must be dequeued.
* @initial_index: in the read() case all buffers are queued up immediately
* in __vb2_init_fileio() and __vb2_perform_fileio() just cycles
* buffers. However, in the write() case no buffers are initially
* queued, instead whenever a buffer is full it is queued up by
* __vb2_perform_fileio(). Only once all available buffers have
* been queued up will __vb2_perform_fileio() start to dequeue
* buffers. This means that initially __vb2_perform_fileio()
* needs to know what buffer index to use when it is queuing up
* the buffers for the first time. That initial index is stored
* in this field. Once it is equal to q->num_buffers all
* available buffers have been queued and __vb2_perform_fileio()
* should start the normal dequeue/queue cycle.
*
* 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_plane p;
struct v4l2_buffer b;
struct vb2_fileio_buf bufs[VIDEO_MAX_FRAME];
unsigned int cur_index;
unsigned int initial_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 (WARN_ON((read && !(q->io_modes & VB2_READ)) ||
(!read && !(q->io_modes & VB2_WRITE))))
return -EINVAL;
/*
* 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;
q->fileio = fileio;
ret = __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) {
ret = -EINVAL;
goto err_reqbufs;
}
fileio->bufs[i].size = vb2_plane_size(q->bufs[i], 0);
}
/*
* Read mode requires pre queuing of all buffers.
*/
if (read) {
bool is_multiplanar = V4L2_TYPE_IS_MULTIPLANAR(q->type);
/*
* 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;
if (is_multiplanar) {
memset(&fileio->p, 0, sizeof(fileio->p));
b->m.planes = &fileio->p;
b->length = 1;
}
b->memory = q->memory;
b->index = i;
ret = vb2_internal_qbuf(q, b);
if (ret)
goto err_reqbufs;
fileio->bufs[i].queued = 1;
}
/*
* All buffers have been queued, so mark that by setting
* initial_index to q->num_buffers
*/
fileio->initial_index = q->num_buffers;
fileio->cur_index = q->num_buffers;
}
/*
* Start streaming.
*/
ret = vb2_internal_streamon(q, q->type);
if (ret)
goto err_reqbufs;
return ret;
err_reqbufs:
fileio->req.count = 0;
__reqbufs(q, &fileio->req);
err_kfree:
q->fileio = NULL;
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) {
vb2_internal_streamoff(q, q->type);
q->fileio = NULL;
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;
bool is_multiplanar = V4L2_TYPE_IS_MULTIPLANAR(q->type);
/*
* When using write() to write data to an output video node the vb2 core
* should set timestamps if V4L2_BUF_FLAG_TIMESTAMP_COPY is set. Nobody
* else is able to provide this information with the write() operation.
*/
bool set_timestamp = !read &&
(q->timestamp_flags & V4L2_BUF_FLAG_TIMESTAMP_MASK) ==
V4L2_BUF_FLAG_TIMESTAMP_COPY;
int ret, index;
dprintk(3, "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 (!vb2_fileio_is_active(q)) {
ret = __vb2_init_fileio(q, read);
dprintk(3, "vb2_init_fileio result: %d\n", ret);
if (ret)
return ret;
}
fileio = q->fileio;
/*
* Check if we need to dequeue the buffer.
*/
index = fileio->cur_index;
if (index >= q->num_buffers) {
/*
* Call vb2_dqbuf to get buffer back.
*/
memset(&fileio->b, 0, sizeof(fileio->b));
fileio->b.type = q->type;
fileio->b.memory = q->memory;
if (is_multiplanar) {
memset(&fileio->p, 0, sizeof(fileio->p));
fileio->b.m.planes = &fileio->p;
fileio->b.length = 1;
}
ret = vb2_internal_dqbuf(q, &fileio->b, nonblock);
dprintk(5, "vb2_dqbuf result: %d\n", ret);
if (ret)
return ret;
fileio->dq_count += 1;
fileio->cur_index = index = fileio->b.index;
buf = &fileio->bufs[index];
/*
* Get number of bytes filled by the driver
*/
buf->pos = 0;
buf->queued = 0;
buf->size = read ? vb2_get_plane_payload(q->bufs[index], 0)
: vb2_plane_size(q->bufs[index], 0);
/* Compensate for data_offset on read in the multiplanar case. */
if (is_multiplanar && read &&
fileio->b.m.planes[0].data_offset < buf->size) {
buf->pos = fileio->b.m.planes[0].data_offset;
buf->size -= buf->pos;
}
} else {
buf = &fileio->bufs[index];
}
/*
* 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, "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, "error copying data\n");
return -EFAULT;
}
/*
* 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, "read limit reached\n");
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;
if (is_multiplanar) {
memset(&fileio->p, 0, sizeof(fileio->p));
fileio->p.bytesused = buf->pos;
fileio->b.m.planes = &fileio->p;
fileio->b.length = 1;
}
if (set_timestamp)
v4l2_get_timestamp(&fileio->b.timestamp);
ret = vb2_internal_qbuf(q, &fileio->b);
dprintk(5, "vb2_dbuf result: %d\n", ret);
if (ret)
return ret;
/*
* Buffer has been queued, update the status
*/
buf->pos = 0;
buf->queued = 1;
buf->size = vb2_plane_size(q->bufs[index], 0);
fileio->q_count += 1;
/*
* If we are queuing up buffers for the first time, then
* increase initial_index by one.
*/
if (fileio->initial_index < q->num_buffers)
fileio->initial_index++;
/*
* The next buffer to use is either a buffer that's going to be
* queued for the first time (initial_index < q->num_buffers)
* or it is equal to q->num_buffers, meaning that the next
* time we need to dequeue a buffer since we've now queued up
* all the 'first time' buffers.
*/
fileio->cur_index = fileio->initial_index;
}
/*
* Return proper number of bytes processed.
*/
if (ret == 0)
ret = count;
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, const char __user *data, size_t count,
loff_t *ppos, int nonblocking)
{
return __vb2_perform_fileio(q, (char __user *) data, count,
ppos, nonblocking, 0);
}
EXPORT_SYMBOL_GPL(vb2_write);
struct vb2_threadio_data {
struct task_struct *thread;
vb2_thread_fnc fnc;
void *priv;
bool stop;
};
static int vb2_thread(void *data)
{
struct vb2_queue *q = data;
struct vb2_threadio_data *threadio = q->threadio;
struct vb2_fileio_data *fileio = q->fileio;
bool set_timestamp = false;
int prequeue = 0;
int index = 0;
int ret = 0;
if (V4L2_TYPE_IS_OUTPUT(q->type)) {
prequeue = q->num_buffers;
set_timestamp =
(q->timestamp_flags & V4L2_BUF_FLAG_TIMESTAMP_MASK) ==
V4L2_BUF_FLAG_TIMESTAMP_COPY;
}
set_freezable();
for (;;) {
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;
if (prequeue) {
fileio->b.index = index++;
prequeue--;
} else {
call_void_qop(q, wait_finish, q);
if (!threadio->stop)
ret = vb2_internal_dqbuf(q, &fileio->b, 0);
call_void_qop(q, wait_prepare, q);
dprintk(5, "file io: vb2_dqbuf result: %d\n", ret);
}
if (ret || threadio->stop)
break;
try_to_freeze();
vb = q->bufs[fileio->b.index];
if (!(fileio->b.flags & V4L2_BUF_FLAG_ERROR))
if (threadio->fnc(vb, threadio->priv))
break;
call_void_qop(q, wait_finish, q);
if (set_timestamp)
v4l2_get_timestamp(&fileio->b.timestamp);
if (!threadio->stop)
ret = vb2_internal_qbuf(q, &fileio->b);
call_void_qop(q, wait_prepare, q);
if (ret || threadio->stop)
break;
}
/* Hmm, linux becomes *very* unhappy without this ... */
while (!kthread_should_stop()) {
set_current_state(TASK_INTERRUPTIBLE);
schedule();
}
return 0;
}
/*
* This function should not be used for anything else but the videobuf2-dvb
* support. If you think you have another good use-case for this, then please
* contact the linux-media mailinglist first.
*/
int vb2_thread_start(struct vb2_queue *q, vb2_thread_fnc fnc, void *priv,
const char *thread_name)
{
struct vb2_threadio_data *threadio;
int ret = 0;
if (q->threadio)
return -EBUSY;
if (vb2_is_busy(q))
return -EBUSY;
if (WARN_ON(q->fileio))
return -EBUSY;
threadio = kzalloc(sizeof(*threadio), GFP_KERNEL);
if (threadio == NULL)
return -ENOMEM;
threadio->fnc = fnc;
threadio->priv = priv;
ret = __vb2_init_fileio(q, !V4L2_TYPE_IS_OUTPUT(q->type));
dprintk(3, "file io: vb2_init_fileio result: %d\n", ret);
if (ret)
goto nomem;
q->threadio = threadio;
threadio->thread = kthread_run(vb2_thread, q, "vb2-%s", thread_name);
if (IS_ERR(threadio->thread)) {
ret = PTR_ERR(threadio->thread);
threadio->thread = NULL;
goto nothread;
}
return 0;
nothread:
__vb2_cleanup_fileio(q);
nomem:
kfree(threadio);
return ret;
}
EXPORT_SYMBOL_GPL(vb2_thread_start);
int vb2_thread_stop(struct vb2_queue *q)
{
struct vb2_threadio_data *threadio = q->threadio;
struct vb2_fileio_data *fileio = q->fileio;
int err;
if (threadio == NULL)
return 0;
call_void_qop(q, wait_finish, q);
threadio->stop = true;
vb2_internal_streamoff(q, q->type);
call_void_qop(q, wait_prepare, q);
err = kthread_stop(threadio->thread);
q->fileio = NULL;
fileio->req.count = 0;
vb2_reqbufs(q, &fileio->req);
kfree(fileio);
threadio->thread = NULL;
kfree(threadio);
q->fileio = NULL;
q->threadio = NULL;
return err;
}
EXPORT_SYMBOL_GPL(vb2_thread_stop);
/*
* 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 mutex *lock)
{
struct video_device *vdev = video_devdata(file);
if (lock)
mutex_lock(lock);
if (file->private_data == vdev->queue->owner) {
vb2_queue_release(vdev->queue);
vdev->queue->owner = NULL;
}
if (lock)
mutex_unlock(lock);
return v4l2_fh_release(file);
}
EXPORT_SYMBOL_GPL(_vb2_fop_release);
int vb2_fop_release(struct file *file)
{
struct video_device *vdev = video_devdata(file);
struct mutex *lock = vdev->queue->lock ? vdev->queue->lock : vdev->lock;
return _vb2_fop_release(file, lock);
}
EXPORT_SYMBOL_GPL(vb2_fop_release);
ssize_t vb2_fop_write(struct file *file, const 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 res;
void *fileio;
/*
* If this helper doesn't know how to lock, then you shouldn't be using
* it but you should write your own.
*/
WARN_ON(!lock);
if (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 (!fileio && q->fileio)
q->owner = file->private_data;
if (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 <pawel@osciak.com>, Marek Szyprowski");
MODULE_LICENSE("GPL");
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