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[media] v4l: vb2: add support for shared buffer (dma_buf) 

This patch adds support for DMABUF memory type in videobuf2. It calls relevant
APIs of dma_buf for v4l reqbuf / qbuf / dqbuf operations.
For this version, the support is for videobuf2 as a user of the shared buffer;
so the allocation of the buffer is done outside of V4L2. [A sample allocator of
dma-buf shared buffer is given at [1]]
[1]: Rob Clark's DRM:
   https://github.com/robclark/kernel-omap4/commits/drmplane-dmabuf
   [original work in the PoC for buffer sharing]

Signed-off-by: Tomasz Stanislawski <t.stanislaws@samsung.com>
Signed-off-by: Sumit Semwal <sumit.semwal@ti.com>
Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Tested-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
This commit is contained in:
Sumit Semwal 2012-06-14 10:37:37 -03:00 committed by Mauro Carvalho Chehab
parent 4b9c1cb641
commit c538404869
3 changed files with 231 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
drivers/media/v4l2-core/Kconfig
View File

@ -59,6 +59,7 @@ config VIDEOBUF_DVB
# Used by drivers that need Videobuf2 modules
config VIDEOBUF2_CORE
select DMA_SHARED_BUFFER
tristate
config VIDEOBUF2_MEMOPS

206
drivers/media/v4l2-core/videobuf2-core.c
View File

@ -108,6 +108,36 @@ static void __vb2_buf_userptr_put(struct vb2_buffer *vb)
}
}
/**
* __vb2_plane_dmabuf_put() - release memory associated with
* a DMABUF shared plane
*/
static void __vb2_plane_dmabuf_put(struct vb2_queue *q, struct vb2_plane *p)
{
if (!p->mem_priv)
return;
if (p->dbuf_mapped)
call_memop(q, unmap_dmabuf, p->mem_priv);
call_memop(q, detach_dmabuf, p->mem_priv);
dma_buf_put(p->dbuf);
memset(p, 0, sizeof(*p));
}
/**
* __vb2_buf_dmabuf_put() - release memory associated with
* a DMABUF shared buffer
*/
static void __vb2_buf_dmabuf_put(struct vb2_buffer *vb)
{
struct vb2_queue *q = vb->vb2_queue;
unsigned int plane;
for (plane = 0; plane < vb->num_planes; ++plane)
__vb2_plane_dmabuf_put(q, &vb->planes[plane]);
}
/**
* __setup_offsets() - setup unique offsets ("cookies") for every plane in
* every buffer on the queue
@ -230,6 +260,8 @@ static void __vb2_free_mem(struct vb2_queue *q, unsigned int buffers)
/* 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);
}
@ -362,6 +394,8 @@ static void __fill_v4l2_buffer(struct vb2_buffer *vb, struct v4l2_buffer *b)
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;
}
/*
@ -453,6 +487,20 @@ static int __verify_mmap_ops(struct vb2_queue *q)
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.
@ -460,7 +508,8 @@ static int __verify_mmap_ops(struct vb2_queue *q)
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) {
if (memory != V4L2_MEMORY_MMAP && memory != V4L2_MEMORY_USERPTR &&
memory != V4L2_MEMORY_DMABUF) {
dprintk(1, "reqbufs: unsupported memory type\n");
return -EINVAL;
}
@ -484,6 +533,11 @@ static int __verify_memory_type(struct vb2_queue *q,
return -EINVAL;
}
if (memory == V4L2_MEMORY_DMABUF && __verify_dmabuf_ops(q)) {
dprintk(1, "reqbufs: DMABUF for current setup unsupported\n");
return -EINVAL;
}
/*
* Place the busy tests at the end: -EBUSY can be ignored when
* create_bufs is called with count == 0, but count == 0 should still
@ -845,6 +899,16 @@ static void __fill_vb2_buffer(struct vb2_buffer *vb, const struct v4l2_buffer *b
b->m.planes[plane].length;
}
}
if (b->memory == V4L2_MEMORY_DMABUF) {
for (plane = 0; plane < vb->num_planes; ++plane) {
v4l2_planes[plane].m.fd =
b->m.planes[plane].m.fd;
v4l2_planes[plane].length =
b->m.planes[plane].length;
v4l2_planes[plane].data_offset =
b->m.planes[plane].data_offset;
}
}
} else {
/*
* Single-planar buffers do not use planes array,
@ -859,6 +923,13 @@ static void __fill_vb2_buffer(struct vb2_buffer *vb, const struct v4l2_buffer *b
v4l2_planes[0].m.userptr = b->m.userptr;
v4l2_planes[0].length = b->length;
}
if (b->memory == V4L2_MEMORY_DMABUF) {
v4l2_planes[0].m.fd = b->m.fd;
v4l2_planes[0].length = b->length;
v4l2_planes[0].data_offset = 0;
}
}
vb->v4l2_buf.field = b->field;
@ -958,6 +1029,107 @@ static int __qbuf_mmap(struct vb2_buffer *vb, const struct v4l2_buffer *b)
return 0;
}
/**
* __qbuf_dmabuf() - handle qbuf of a DMABUF buffer
*/
static int __qbuf_dmabuf(struct vb2_buffer *vb, const struct v4l2_buffer *b)
{
struct v4l2_plane planes[VIDEO_MAX_PLANES];
struct vb2_queue *q = vb->vb2_queue;
void *mem_priv;
unsigned int plane;
int ret;
int write = !V4L2_TYPE_IS_OUTPUT(q->type);
/* Verify and copy relevant information provided by the userspace */
__fill_vb2_buffer(vb, b, planes);
for (plane = 0; plane < vb->num_planes; ++plane) {
struct dma_buf *dbuf = dma_buf_get(planes[plane].m.fd);
if (IS_ERR_OR_NULL(dbuf)) {
dprintk(1, "qbuf: invalid dmabuf fd for plane %d\n",
plane);
ret = -EINVAL;
goto err;
}
/* use DMABUF size if length is not provided */
if (planes[plane].length == 0)
planes[plane].length = dbuf->size;
if (planes[plane].length < planes[plane].data_offset +
q->plane_sizes[plane]) {
ret = -EINVAL;
goto err;
}
/* Skip the plane if already verified */
if (dbuf == vb->planes[plane].dbuf &&
vb->v4l2_planes[plane].length == planes[plane].length) {
dma_buf_put(dbuf);
continue;
}
dprintk(1, "qbuf: buffer for plane %d changed\n", plane);
/* Release previously acquired memory if present */
__vb2_plane_dmabuf_put(q, &vb->planes[plane]);
memset(&vb->v4l2_planes[plane], 0, sizeof(struct v4l2_plane));
/* Acquire each plane's memory */
mem_priv = call_memop(q, attach_dmabuf, q->alloc_ctx[plane],
dbuf, planes[plane].length, write);
if (IS_ERR(mem_priv)) {
dprintk(1, "qbuf: failed to attach dmabuf\n");
ret = PTR_ERR(mem_priv);
dma_buf_put(dbuf);
goto err;
}
vb->planes[plane].dbuf = dbuf;
vb->planes[plane].mem_priv = mem_priv;
}
/* TODO: This pins the buffer(s) with dma_buf_map_attachment()).. but
* really we want to do this just before the DMA, not while queueing
* the buffer(s)..
*/
for (plane = 0; plane < vb->num_planes; ++plane) {
ret = call_memop(q, map_dmabuf, vb->planes[plane].mem_priv);
if (ret) {
dprintk(1, "qbuf: failed to map dmabuf for plane %d\n",
plane);
goto err;
}
vb->planes[plane].dbuf_mapped = 1;
}
/*
* Call driver-specific initialization on the newly acquired buffer,
* if provided.
*/
ret = call_qop(q, buf_init, vb);
if (ret) {
dprintk(1, "qbuf: buffer initialization failed\n");
goto err;
}
/*
* Now that everything is in order, copy relevant information
* provided by userspace.
*/
for (plane = 0; plane < vb->num_planes; ++plane)
vb->v4l2_planes[plane] = planes[plane];
return 0;
err:
/* In case of errors, release planes that were already acquired */
__vb2_buf_dmabuf_put(vb);
return ret;
}
/**
* __enqueue_in_driver() - enqueue a vb2_buffer in driver for processing
*/
@ -982,6 +1154,9 @@ static int __buf_prepare(struct vb2_buffer *vb, const struct v4l2_buffer *b)
case V4L2_MEMORY_USERPTR:
ret = __qbuf_userptr(vb, b);
break;
case V4L2_MEMORY_DMABUF:
ret = __qbuf_dmabuf(vb, b);
break;
default:
WARN(1, "Invalid queue type\n");
ret = -EINVAL;
@ -1302,6 +1477,30 @@ int vb2_wait_for_all_buffers(struct vb2_queue *q)
}
EXPORT_SYMBOL_GPL(vb2_wait_for_all_buffers);
/**
* __vb2_dqbuf() - bring back the buffer to the DEQUEUED state
*/
static void __vb2_dqbuf(struct vb2_buffer *vb)
{
struct vb2_queue *q = vb->vb2_queue;
unsigned int i;
/* nothing to do if the buffer is already dequeued */
if (vb->state == VB2_BUF_STATE_DEQUEUED)
return;
vb->state = VB2_BUF_STATE_DEQUEUED;
/* unmap DMABUF buffer */
if (q->memory == V4L2_MEMORY_DMABUF)
for (i = 0; i < vb->num_planes; ++i) {
if (!vb->planes[i].dbuf_mapped)
continue;
call_memop(q, unmap_dmabuf, vb->planes[i].mem_priv);
vb->planes[i].dbuf_mapped = 0;
}
}
/**
* vb2_dqbuf() - Dequeue a buffer to the userspace
* @q: videobuf2 queue
@ -1363,11 +1562,12 @@ int vb2_dqbuf(struct vb2_queue *q, struct v4l2_buffer *b, bool nonblocking)
__fill_v4l2_buffer(vb, b);
/* Remove from videobuf queue */
list_del(&vb->queued_entry);
/* go back to dequeued state */
__vb2_dqbuf(vb);
dprintk(1, "dqbuf of buffer %d, with state %d\n",
vb->v4l2_buf.index, vb->state);
vb->state = VB2_BUF_STATE_DEQUEUED;
return 0;
}
EXPORT_SYMBOL_GPL(vb2_dqbuf);
@ -1406,7 +1606,7 @@ static void __vb2_queue_cancel(struct vb2_queue *q)
* Reinitialize all buffers for next use.
*/
for (i = 0; i < q->num_buffers; ++i)
q->bufs[i]->state = VB2_BUF_STATE_DEQUEUED;
__vb2_dqbuf(q->bufs[i]);
}
/**

27
include/media/videobuf2-core.h
View File

@ -16,6 +16,7 @@
#include <linux/mutex.h>
#include <linux/poll.h>
#include <linux/videodev2.h>
#include <linux/dma-buf.h>
struct vb2_alloc_ctx;
struct vb2_fileio_data;
@ -41,6 +42,20 @@ struct vb2_fileio_data;
* argument to other ops in this structure
* @put_userptr: inform the allocator that a USERPTR buffer will no longer
* be used
* @attach_dmabuf: attach a shared struct dma_buf for a hardware operation;
* used for DMABUF memory types; alloc_ctx is the alloc context
* dbuf is the shared dma_buf; returns NULL on failure;
* allocator private per-buffer structure on success;
* this needs to be used for further accesses to the buffer
* @detach_dmabuf: inform the exporter of the buffer that the current DMABUF
* buffer is no longer used; the buf_priv argument is the
* allocator private per-buffer structure previously returned
* from the attach_dmabuf callback
* @map_dmabuf: request for access to the dmabuf from allocator; the allocator
* of dmabuf is informed that this driver is going to use the
* dmabuf
* @unmap_dmabuf: releases access control to the dmabuf - allocator is notified
* that this driver is done using the dmabuf for now
* @vaddr: return a kernel virtual address to a given memory buffer
* associated with the passed private structure or NULL if no
* such mapping exists
@ -56,6 +71,8 @@ struct vb2_fileio_data;
* Required ops for USERPTR types: get_userptr, put_userptr.
* Required ops for MMAP types: alloc, put, num_users, mmap.
* Required ops for read/write access types: alloc, put, num_users, vaddr
* Required ops for DMABUF types: attach_dmabuf, detach_dmabuf, map_dmabuf,
* unmap_dmabuf.
*/
struct vb2_mem_ops {
void *(*alloc)(void *alloc_ctx, unsigned long size);
@ -65,6 +82,12 @@ struct vb2_mem_ops {
unsigned long size, int write);
void (*put_userptr)(void *buf_priv);
void *(*attach_dmabuf)(void *alloc_ctx, struct dma_buf *dbuf,
unsigned long size, int write);
void (*detach_dmabuf)(void *buf_priv);
int (*map_dmabuf)(void *buf_priv);
void (*unmap_dmabuf)(void *buf_priv);
void *(*vaddr)(void *buf_priv);
void *(*cookie)(void *buf_priv);
@ -75,6 +98,8 @@ struct vb2_mem_ops {
struct vb2_plane {
void *mem_priv;
struct dma_buf *dbuf;
unsigned int dbuf_mapped;
};
/**
@ -83,12 +108,14 @@ struct vb2_plane {
* @VB2_USERPTR: driver supports USERPTR with streaming API
* @VB2_READ: driver supports read() style access
* @VB2_WRITE: driver supports write() style access
* @VB2_DMABUF: driver supports DMABUF with streaming API
*/
enum vb2_io_modes {
VB2_MMAP = (1 << 0),
VB2_USERPTR = (1 << 1),
VB2_READ = (1 << 2),
VB2_WRITE = (1 << 3),
VB2_DMABUF = (1 << 4),
};
/**