media: vimc: Add support for contiguous DMA buffers
authorLaurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Fri, 30 Jul 2021 13:18:29 +0000 (15:18 +0200)
committerMauro Carvalho Chehab <mchehab@kernel.org>
Wed, 16 Feb 2022 11:47:02 +0000 (12:47 +0100)
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>
Documentation/admin-guide/media/vimc.rst
drivers/media/test-drivers/vimc/Kconfig
drivers/media/test-drivers/vimc/vimc-capture.c
drivers/media/test-drivers/vimc/vimc-common.h
drivers/media/test-drivers/vimc/vimc-core.c

index 180507d..0b07f05 100644 (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
index da4b2ad..ea37a10 100644 (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
index 5e9fd90..d1e2d07 100644 (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) {
index a289434..ba19307 100644 (file)
 
 #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
  *
index 4b0ae6f..06edf9d 100644 (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>
 
 #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;