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Message-ID: <CAKnK67SDyFCbLjpwzY9JQiBHJTgpF9uXOq+GUBW7oWv_5gZzbA@mail.gmail.com>
Date: Fri, 2 Dec 2011 10:35:00 -0600
From: "Aguirre, Sergio" <saaguirre@...com>
To: Ming Lei <ming.lei@...onical.com>
Cc: Mauro Carvalho Chehab <mchehab@...radead.org>,
Tony Lindgren <tony@...mide.com>,
Sylwester Nawrocki <snjw23@...il.com>,
Greg KH <greg@...ah.com>, Alan Cox <alan@...rguk.ukuu.org.uk>,
linux-omap@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
linux-kernel@...r.kernel.org
Subject: Re: [RFC PATCH v1 4/7] media: videobuf2: introduce VIDEOBUF2_PAGE memops
Hi Ming,
On Fri, Dec 2, 2011 at 3:12 AM, Ming Lei <ming.lei@...onical.com> wrote:
> DMA contig memory resource is very limited and precious, also
> accessing to it from CPU is very slow on some platform.
>
> For some cases(such as the comming face detection driver), DMA Streaming
> buffer is enough, so introduce VIDEOBUF2_PAGE to allocate continuous
> physical memory but letting video device driver to handle DMA buffer mapping
> and unmapping things.
>
> Signed-off-by: Ming Lei <ming.lei@...onical.com>
> ---
> drivers/media/video/Kconfig | 4 +
> drivers/media/video/Makefile | 1 +
> drivers/media/video/videobuf2-page.c | 115 ++++++++++++++++++++++++++++++++++
> include/media/videobuf2-page.h | 20 ++++++
> 4 files changed, 140 insertions(+), 0 deletions(-)
> create mode 100644 drivers/media/video/videobuf2-page.c
> create mode 100644 include/media/videobuf2-page.h
>
> diff --git a/drivers/media/video/Kconfig b/drivers/media/video/Kconfig
> index 4e8a0c4..5684a00 100644
> --- a/drivers/media/video/Kconfig
> +++ b/drivers/media/video/Kconfig
> @@ -60,6 +60,10 @@ config VIDEOBUF2_VMALLOC
> select VIDEOBUF2_MEMOPS
> tristate
>
> +config VIDEOBUF2_PAGE
> + select VIDEOBUF2_CORE
> + select VIDEOBUF2_MEMOPS
> + tristate
>
> config VIDEOBUF2_DMA_SG
> #depends on HAS_DMA
> diff --git a/drivers/media/video/Makefile b/drivers/media/video/Makefile
> index ddeaa6c..bc797f2 100644
> --- a/drivers/media/video/Makefile
> +++ b/drivers/media/video/Makefile
> @@ -125,6 +125,7 @@ obj-$(CONFIG_VIDEO_BTCX) += btcx-risc.o
> obj-$(CONFIG_VIDEOBUF2_CORE) += videobuf2-core.o
> obj-$(CONFIG_VIDEOBUF2_MEMOPS) += videobuf2-memops.o
> obj-$(CONFIG_VIDEOBUF2_VMALLOC) += videobuf2-vmalloc.o
> +obj-$(CONFIG_VIDEOBUF2_PAGE) += videobuf2-page.o
> obj-$(CONFIG_VIDEOBUF2_DMA_CONTIG) += videobuf2-dma-contig.o
> obj-$(CONFIG_VIDEOBUF2_DMA_SG) += videobuf2-dma-sg.o
>
> diff --git a/drivers/media/video/videobuf2-page.c b/drivers/media/video/videobuf2-page.c
> new file mode 100644
> index 0000000..b3f003a
> --- /dev/null
> +++ b/drivers/media/video/videobuf2-page.c
> @@ -0,0 +1,115 @@
> +/*
> + * videobuf2-page.c - page memory allocator for videobuf2
> + *
> + * Copyright (C) 2011 Canonical Ltd.
> + *
> + * Author: Ming Lei <ming.lei@...onical.com>
> + *
> + * 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/module.h>
> +#include <linux/mm.h>
> +#include <linux/slab.h>
> +
> +#include <media/videobuf2-core.h>
> +#include <media/videobuf2-memops.h>
> +
> +struct vb2_page_buf {
> + void *vaddr;
> + unsigned long size;
> + atomic_t refcount;
> + struct vb2_vmarea_handler handler;
> +};
> +
> +static void vb2_page_put(void *buf_priv);
> +
> +static void *vb2_page_alloc(void *alloc_ctx, unsigned long size)
> +{
> + struct vb2_page_buf *buf;
> +
> + buf = kzalloc(sizeof *buf, GFP_KERNEL);
> + if (!buf)
> + return NULL;
> +
> + buf->size = size;
> + buf->vaddr = (void *)__get_free_pages(GFP_KERNEL,
> + get_order(buf->size));
> + buf->handler.refcount = &buf->refcount;
> + buf->handler.put = vb2_page_put;
> + buf->handler.arg = buf;
> +
> + if (!buf->vaddr) {
> + printk(KERN_ERR "page of size %ld failed\n", buf->size);
> + kfree(buf);
> + return NULL;
> + }
> +
> + atomic_inc(&buf->refcount);
> + printk(KERN_DEBUG "Allocated page buffer of size %ld at vaddr=%p\n",
> + buf->size, buf->vaddr);
> +
> + return buf;
> +}
> +
> +static void vb2_page_put(void *buf_priv)
> +{
> + struct vb2_page_buf *buf = buf_priv;
> +
> + if (atomic_dec_and_test(&buf->refcount)) {
> + printk(KERN_DEBUG "%s: Freeing page mem at vaddr=%p\n",
> + __func__, buf->vaddr);
> + free_pages((unsigned long)buf->vaddr, get_order(buf->size));
> + kfree(buf);
> + }
> +}
> +
> +static void *vb2_page_vaddr(void *buf_priv)
> +{
> + struct vb2_page_buf *buf = buf_priv;
> +
> + BUG_ON(!buf);
> +
> + if (!buf->vaddr) {
> + printk(KERN_ERR "Address of an unallocated plane requested\n");
> + return NULL;
> + }
> +
> + return buf->vaddr;
> +}
> +
> +static unsigned int vb2_page_num_users(void *buf_priv)
> +{
> + struct vb2_page_buf *buf = buf_priv;
> + return atomic_read(&buf->refcount);
> +}
> +
> +static int vb2_page_mmap(void *buf_priv, struct vm_area_struct *vma)
> +{
> + struct vb2_page_buf *buf = buf_priv;
> +
> + if (!buf) {
> + printk(KERN_ERR "No memory to map\n");
> + return -EINVAL;
> + }
> +
> + vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
> + return vb2_mmap_pfn_range(vma, virt_to_phys(buf->vaddr),
> + buf->size, &vb2_common_vm_ops,
> + &buf->handler);
> +}
> +
> +const struct vb2_mem_ops vb2_page_memops = {
> + .alloc = vb2_page_alloc,
> + .put = vb2_page_put,
> + .vaddr = vb2_page_vaddr,
> + .mmap = vb2_page_mmap,
> + .num_users = vb2_page_num_users,
> +};
> +EXPORT_SYMBOL_GPL(vb2_page_memops);
> +
> +MODULE_DESCRIPTION("page memory handling routines for videobuf2");
> +MODULE_AUTHOR("Ming Lei");
> +MODULE_LICENSE("GPL");
> diff --git a/include/media/videobuf2-page.h b/include/media/videobuf2-page.h
> new file mode 100644
> index 0000000..29b3e20
> --- /dev/null
> +++ b/include/media/videobuf2-page.h
> @@ -0,0 +1,20 @@
> +/*
> + * videobuf2-vmalloc.h - vmalloc memory allocator for videobuf2
> + *
> + * Copyright (C) 2010 Samsung Electronics
> + *
> + * Author: Pawel Osciak <pawel@...iak.com>
> + *
> + * 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.
> + */
> +
> +#ifndef _MEDIA_VIDEOBUF2_VMALLOC_H
> +#define _MEDIA_VIDEOBUF2_VMALLOC_H
Copy-paste much? :)
Fix header and match above define with something that matches the actual file:
#ifndef _MEDIA_VIDEOBUF2_PAGE_H
#define _MEDIA_VIDEOBUF2_PAGE_H
Regards,
Sergio
> +
> +#include <media/videobuf2-core.h>
> +
> +extern const struct vb2_mem_ops vb2_page_memops;
> +
> +#endif
> --
> 1.7.5.4
>
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