[media] v4l: videobuf2: add DMA scatter/gather allocator
Add an implementation of DMA scatter/gather allocator and handling routines for videobuf2. For mmap operation mode it is implemented on top of alloc_page + sg_set_page/_free_page. For userptr operation mode it is implemented on top of get_user_pages + sg_set_page/put_page. Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@samsung.com> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> CC: Pawel Osciak <pawel@osciak.com> Reviewed-by: Hans Verkuil <hverkuil@xs4all.nl> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
This commit is contained in:
Andrzej Pietrasiewicz
Mauro Carvalho Chehab
parent
1a758d4e84
commit
5ba3f757f0
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@ -60,6 +60,12 @@ config VIDEOBUF2_VMALLOC
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select VIDEOBUF2_MEMOPS
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tristate
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config VIDEOBUF2_DMA_SG
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#depends on HAS_DMA
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select VIDEOBUF2_CORE
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select VIDEOBUF2_MEMOPS
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tristate
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#
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# Multimedia Video device configuration
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#
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@ -115,6 +115,7 @@ obj-$(CONFIG_VIDEOBUF2_CORE) += videobuf2-core.o
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obj-$(CONFIG_VIDEOBUF2_MEMOPS) += videobuf2-memops.o
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obj-$(CONFIG_VIDEOBUF2_VMALLOC) += videobuf2-vmalloc.o
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obj-$(CONFIG_VIDEOBUF2_DMA_CONTIG) += videobuf2-dma-contig.o
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obj-$(CONFIG_VIDEOBUF2_DMA_SG) += videobuf2-dma-sg.o
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obj-$(CONFIG_V4L2_MEM2MEM_DEV) += v4l2-mem2mem.o
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@ -0,0 +1,292 @@
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/*
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* videobuf2-dma-sg.c - dma scatter/gather memory allocator for videobuf2
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*
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* Copyright (C) 2010 Samsung Electronics
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*
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* Author: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation.
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*/
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#include <linux/module.h>
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#include <linux/mm.h>
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#include <linux/scatterlist.h>
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#include <linux/sched.h>
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#include <linux/slab.h>
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#include <linux/vmalloc.h>
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#include <media/videobuf2-core.h>
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#include <media/videobuf2-memops.h>
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#include <media/videobuf2-dma-sg.h>
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struct vb2_dma_sg_buf {
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void *vaddr;
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struct page **pages;
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int write;
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int offset;
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struct vb2_dma_sg_desc sg_desc;
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atomic_t refcount;
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struct vb2_vmarea_handler handler;
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};
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static void vb2_dma_sg_put(void *buf_priv);
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static void *vb2_dma_sg_alloc(void *alloc_ctx, unsigned long size)
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{
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struct vb2_dma_sg_buf *buf;
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int i;
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buf = kzalloc(sizeof *buf, GFP_KERNEL);
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if (!buf)
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return NULL;
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buf->vaddr = NULL;
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buf->write = 0;
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buf->offset = 0;
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buf->sg_desc.size = size;
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buf->sg_desc.num_pages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
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buf->sg_desc.sglist = vmalloc(buf->sg_desc.num_pages *
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sizeof(*buf->sg_desc.sglist));
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if (!buf->sg_desc.sglist)
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goto fail_sglist_alloc;
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memset(buf->sg_desc.sglist, 0, buf->sg_desc.num_pages *
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sizeof(*buf->sg_desc.sglist));
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sg_init_table(buf->sg_desc.sglist, buf->sg_desc.num_pages);
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buf->pages = kzalloc(buf->sg_desc.num_pages * sizeof(struct page *),
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GFP_KERNEL);
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if (!buf->pages)
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goto fail_pages_array_alloc;
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for (i = 0; i < buf->sg_desc.num_pages; ++i) {
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buf->pages[i] = alloc_page(GFP_KERNEL);
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if (NULL == buf->pages[i])
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goto fail_pages_alloc;
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sg_set_page(&buf->sg_desc.sglist[i],
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buf->pages[i], PAGE_SIZE, 0);
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}
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buf->handler.refcount = &buf->refcount;
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buf->handler.put = vb2_dma_sg_put;
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buf->handler.arg = buf;
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atomic_inc(&buf->refcount);
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printk(KERN_DEBUG "%s: Allocated buffer of %d pages\n",
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__func__, buf->sg_desc.num_pages);
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if (!buf->vaddr)
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buf->vaddr = vm_map_ram(buf->pages,
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buf->sg_desc.num_pages,
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-1,
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PAGE_KERNEL);
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return buf;
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fail_pages_alloc:
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while (--i >= 0)
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__free_page(buf->pages[i]);
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fail_pages_array_alloc:
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vfree(buf->sg_desc.sglist);
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fail_sglist_alloc:
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kfree(buf);
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return NULL;
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}
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static void vb2_dma_sg_put(void *buf_priv)
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{
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struct vb2_dma_sg_buf *buf = buf_priv;
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int i = buf->sg_desc.num_pages;
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if (atomic_dec_and_test(&buf->refcount)) {
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printk(KERN_DEBUG "%s: Freeing buffer of %d pages\n", __func__,
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buf->sg_desc.num_pages);
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if (buf->vaddr)
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vm_unmap_ram(buf->vaddr, buf->sg_desc.num_pages);
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vfree(buf->sg_desc.sglist);
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while (--i >= 0)
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__free_page(buf->pages[i]);
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kfree(buf->pages);
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kfree(buf);
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}
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}
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static void *vb2_dma_sg_get_userptr(void *alloc_ctx, unsigned long vaddr,
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unsigned long size, int write)
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{
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struct vb2_dma_sg_buf *buf;
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unsigned long first, last;
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int num_pages_from_user, i;
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buf = kzalloc(sizeof *buf, GFP_KERNEL);
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if (!buf)
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return NULL;
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buf->vaddr = NULL;
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buf->write = write;
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buf->offset = vaddr & ~PAGE_MASK;
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buf->sg_desc.size = size;
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first = (vaddr & PAGE_MASK) >> PAGE_SHIFT;
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last = ((vaddr + size - 1) & PAGE_MASK) >> PAGE_SHIFT;
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buf->sg_desc.num_pages = last - first + 1;
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buf->sg_desc.sglist = vmalloc(
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buf->sg_desc.num_pages * sizeof(*buf->sg_desc.sglist));
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if (!buf->sg_desc.sglist)
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goto userptr_fail_sglist_alloc;
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memset(buf->sg_desc.sglist, 0,
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buf->sg_desc.num_pages * sizeof(*buf->sg_desc.sglist));
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sg_init_table(buf->sg_desc.sglist, buf->sg_desc.num_pages);
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buf->pages = kzalloc(buf->sg_desc.num_pages * sizeof(struct page *),
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GFP_KERNEL);
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if (!buf->pages)
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goto userptr_fail_pages_array_alloc;
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down_read(¤t->mm->mmap_sem);
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num_pages_from_user = get_user_pages(current, current->mm,
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vaddr & PAGE_MASK,
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buf->sg_desc.num_pages,
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write,
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1, /* force */
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buf->pages,
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NULL);
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up_read(¤t->mm->mmap_sem);
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if (num_pages_from_user != buf->sg_desc.num_pages)
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goto userptr_fail_get_user_pages;
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sg_set_page(&buf->sg_desc.sglist[0], buf->pages[0],
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PAGE_SIZE - buf->offset, buf->offset);
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size -= PAGE_SIZE - buf->offset;
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for (i = 1; i < buf->sg_desc.num_pages; ++i) {
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sg_set_page(&buf->sg_desc.sglist[i], buf->pages[i],
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min_t(size_t, PAGE_SIZE, size), 0);
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size -= min_t(size_t, PAGE_SIZE, size);
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}
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return buf;
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userptr_fail_get_user_pages:
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printk(KERN_DEBUG "get_user_pages requested/got: %d/%d]\n",
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num_pages_from_user, buf->sg_desc.num_pages);
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while (--num_pages_from_user >= 0)
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put_page(buf->pages[num_pages_from_user]);
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userptr_fail_pages_array_alloc:
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vfree(buf->sg_desc.sglist);
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userptr_fail_sglist_alloc:
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kfree(buf);
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return NULL;
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}
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/*
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* @put_userptr: inform the allocator that a USERPTR buffer will no longer
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* be used
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*/
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static void vb2_dma_sg_put_userptr(void *buf_priv)
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{
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struct vb2_dma_sg_buf *buf = buf_priv;
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int i = buf->sg_desc.num_pages;
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printk(KERN_DEBUG "%s: Releasing userspace buffer of %d pages\n",
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__func__, buf->sg_desc.num_pages);
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if (buf->vaddr)
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vm_unmap_ram(buf->vaddr, buf->sg_desc.num_pages);
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while (--i >= 0) {
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if (buf->write)
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set_page_dirty_lock(buf->pages[i]);
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put_page(buf->pages[i]);
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}
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vfree(buf->sg_desc.sglist);
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kfree(buf->pages);
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kfree(buf);
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}
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static void *vb2_dma_sg_vaddr(void *buf_priv)
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{
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struct vb2_dma_sg_buf *buf = buf_priv;
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BUG_ON(!buf);
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if (!buf->vaddr)
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buf->vaddr = vm_map_ram(buf->pages,
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buf->sg_desc.num_pages,
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-1,
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PAGE_KERNEL);
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/* add offset in case userptr is not page-aligned */
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return buf->vaddr + buf->offset;
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}
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static unsigned int vb2_dma_sg_num_users(void *buf_priv)
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{
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struct vb2_dma_sg_buf *buf = buf_priv;
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return atomic_read(&buf->refcount);
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}
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static int vb2_dma_sg_mmap(void *buf_priv, struct vm_area_struct *vma)
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{
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struct vb2_dma_sg_buf *buf = buf_priv;
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unsigned long uaddr = vma->vm_start;
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unsigned long usize = vma->vm_end - vma->vm_start;
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int i = 0;
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if (!buf) {
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printk(KERN_ERR "No memory to map\n");
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return -EINVAL;
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}
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do {
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int ret;
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ret = vm_insert_page(vma, uaddr, buf->pages[i++]);
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if (ret) {
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printk(KERN_ERR "Remapping memory, error: %d\n", ret);
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return ret;
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}
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uaddr += PAGE_SIZE;
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usize -= PAGE_SIZE;
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} while (usize > 0);
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/*
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* Use common vm_area operations to track buffer refcount.
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*/
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vma->vm_private_data = &buf->handler;
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vma->vm_ops = &vb2_common_vm_ops;
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vma->vm_ops->open(vma);
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return 0;
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}
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static void *vb2_dma_sg_cookie(void *buf_priv)
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{
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struct vb2_dma_sg_buf *buf = buf_priv;
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return &buf->sg_desc;
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}
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const struct vb2_mem_ops vb2_dma_sg_memops = {
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.alloc = vb2_dma_sg_alloc,
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.put = vb2_dma_sg_put,
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.get_userptr = vb2_dma_sg_get_userptr,
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.put_userptr = vb2_dma_sg_put_userptr,
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.vaddr = vb2_dma_sg_vaddr,
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.mmap = vb2_dma_sg_mmap,
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.num_users = vb2_dma_sg_num_users,
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.cookie = vb2_dma_sg_cookie,
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};
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EXPORT_SYMBOL_GPL(vb2_dma_sg_memops);
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MODULE_DESCRIPTION("dma scatter/gather memory handling routines for videobuf2");
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MODULE_AUTHOR("Andrzej Pietrasiewicz");
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MODULE_LICENSE("GPL");
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@ -0,0 +1,32 @@
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/*
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* videobuf2-dma-sg.h - DMA scatter/gather memory allocator for videobuf2
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*
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* Copyright (C) 2010 Samsung Electronics
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*
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* Author: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation.
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*/
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#ifndef _MEDIA_VIDEOBUF2_DMA_SG_H
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#define _MEDIA_VIDEOBUF2_DMA_SG_H
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#include <media/videobuf2-core.h>
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struct vb2_dma_sg_desc {
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unsigned long size;
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unsigned int num_pages;
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struct scatterlist *sglist;
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};
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static inline struct vb2_dma_sg_desc *vb2_dma_sg_plane_desc(
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struct vb2_buffer *vb, unsigned int plane_no)
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{
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return (struct vb2_dma_sg_desc *)vb2_plane_cookie(vb, plane_no);
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}
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extern const struct vb2_mem_ops vb2_dma_sg_memops;
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#endif
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