Since videobuf-dma-contig is designed to handle physically contiguous
memory, this patch modifies the videobuf-dma-contig code to only accept a
user space pointer to physically contiguous memory. For now only
VM_PFNMAP vmas are supported, so forget hotplug.
On SuperH Mobile we use this with our sh_mobile_ceu_camera driver together
with various multimedia accelerator blocks that are exported to user space
using UIO. The UIO kernel code exports physically contiguous memory to
user space and lets the user space application mmap() this memory and pass
a pointer using the USERPTR interface for V4L2 zero copy operation.
With this approach we support zero copy capture, hardware scaling and
various forms of hardware encoding and decoding.
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Magnus Damm <damm@igel.co.jp>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Paul Mundt <lethal@linux-sh.org>
Acked-by: Mauro Carvalho Chehab <mchehab@infradead.org>
Cc: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Remove the videobuf-dma-contig sync operation. Sync is only needed
for noncoherent buffers, and since videobuf-dma-contig is built on
coherent memory allocators the memory is by definition always in sync.
Reported-by: Matthieu CASTET <matthieu.castet@parrot.com>
Signed-off-by: Magnus Damm <damm@igel.co.jp>
Reviewed-by: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
This patch fixes a free-without-alloc bug for V4L2_MEMORY_USERPTR
video buffers.
Signed-off-by: Magnus Damm <damm@igel.co.jp>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
This is V3 of the physically contiguous videobuf queues patch.
Useful for hardware such as the SuperH Mobile CEU which doesn't
support scatter gatter bus mastering.
Since it may be difficult to allocate large chunks of physically
contiguous memory after some uptime due to fragmentation, this code
allocates memory using dma_alloc_coherent(). Architectures supporting
dma_declare_coherent_memory() can easily avoid fragmentation issues
by using dma_declare_coherent_memory() to force dma_alloc_coherent()
to allocate from a certain pre-allocated memory area.
Changes since V2
- use dma_handle for physical address
- use "scatter gather" instead of "scatter gatter"
Changes since V1:
- use dev_err() instead of pr_err()
- remember size in struct videobuf_dma_contig_memory
- keep struct videobuf_dma_contig_memory in .c file
- let videobuf_to_dma_contig() return dma_addr_t
- implement __videobuf_sync()
- return statements, white space and other minor fixes
Signed-off-by: Magnus Damm <damm@igel.co.jp>
Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@pengutronix.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
