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media: vimc: Add support for contiguous DMA buffers 

The vimc driver is used for testing purpose, and some test use cases
involve sharing buffers with a consumer device. Consumers often require
DMA contiguous memory, which vimc doesn't currently support. This leads
in the best case to usage of bounce buffers, which is very slow, and in
the worst case in a complete failure.

Add support for the dma-contig allocator in vimc to support those use
cases properly. The allocator is selected through a new "allocator"
module parameter, which defaults to vmalloc.

[hverkuil: add missing 'select VIDEOBUF2_DMA_CONFIG' to Kconfig]

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
This commit is contained in:
Laurent Pinchart 2021-07-30 15:18:29 +02:00 committed by Mauro Carvalho Chehab
parent 79e8c421a0
commit 4a2e0a806c
5 changed files with 38 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

13
Documentation/admin-guide/media/vimc.rst
View File

@ -76,3 +76,16 @@ vimc-capture:
* 1 Pad sink
* 1 Pad source
Module options
--------------
Vimc has a module parameter to configure the driver.
* ``allocator=<unsigned int>``
memory allocator selection, default is 0. It specifies the way buffers
will be allocated.
- 0: vmalloc
- 1: dma-contig

1
drivers/media/test-drivers/vimc/Kconfig
View File

@ -7,6 +7,7 @@ config VIDEO_VIMC
select MEDIA_CONTROLLER
select VIDEO_V4L2_SUBDEV_API
select VIDEOBUF2_VMALLOC
select VIDEOBUF2_DMA_CONTIG
select VIDEO_V4L2_TPG
help
Skeleton driver for Virtual Media Controller

9
drivers/media/test-drivers/vimc/vimc-capture.c
View File

@ -7,6 +7,7 @@
#include <media/v4l2-ioctl.h>
#include <media/videobuf2-core.h>
#include <media/videobuf2-dma-contig.h>
#include <media/videobuf2-vmalloc.h>
#include "vimc-common.h"
@ -423,14 +424,18 @@ static struct vimc_ent_device *vimc_cap_add(struct vimc_device *vimc,
/* Initialize the vb2 queue */
q = &vcap->queue;
q->type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
q->io_modes = VB2_MMAP | VB2_DMABUF | VB2_USERPTR;
q->io_modes = VB2_MMAP | VB2_DMABUF;
if (vimc_allocator == VIMC_ALLOCATOR_VMALLOC)
q->io_modes |= VB2_USERPTR;
q->drv_priv = vcap;
q->buf_struct_size = sizeof(struct vimc_cap_buffer);
q->ops = &vimc_cap_qops;
q->mem_ops = &vb2_vmalloc_memops;
q->mem_ops = vimc_allocator == VIMC_ALLOCATOR_DMA_CONTIG
? &vb2_dma_contig_memops : &vb2_vmalloc_memops;
q->timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC;
q->min_buffers_needed = 2;
q->lock = &vcap->lock;
q->dev = v4l2_dev->dev;
ret = vb2_queue_init(q);
if (ret) {

7
drivers/media/test-drivers/vimc/vimc-common.h
View File

@ -35,6 +35,13 @@
#define VIMC_PIX_FMT_MAX_CODES 8
extern unsigned int vimc_allocator;
enum vimc_allocator_type {
VIMC_ALLOCATOR_VMALLOC = 0,
VIMC_ALLOCATOR_DMA_CONTIG = 1,
};
/**
* vimc_colorimetry_clamp - Adjust colorimetry parameters
*

10
drivers/media/test-drivers/vimc/vimc-core.c
View File

@ -5,6 +5,7 @@
* Copyright (C) 2015-2017 Helen Koike <helen.fornazier@gmail.com>
*/
#include <linux/dma-mapping.h>
#include <linux/font.h>
#include <linux/init.h>
#include <linux/module.h>
@ -15,6 +16,12 @@
#include "vimc-common.h"
unsigned int vimc_allocator;
module_param_named(allocator, vimc_allocator, uint, 0444);
MODULE_PARM_DESC(allocator, " memory allocator selection, default is 0.\n"
"\t\t 0 == vmalloc\n"
"\t\t 1 == dma-contig");
#define VIMC_MDEV_MODEL_NAME "VIMC MDEV"
#define VIMC_ENT_LINK(src, srcpad, sink, sinkpad, link_flags) { \
@ -278,6 +285,9 @@ static int vimc_probe(struct platform_device *pdev)
tpg_set_font(font->data);
if (vimc_allocator == VIMC_ALLOCATOR_DMA_CONTIG)
dma_coerce_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32));
vimc = kzalloc(sizeof(*vimc), GFP_KERNEL);
if (!vimc)
return -ENOMEM;