[PATCH 4/7] v4l: videobuf2: add IOMMU based DMA memory allocator
Marek Szyprowski
m.szyprowski at samsung.com
Mon Apr 18 05:26:41 EDT 2011
From: Andrzej Pietrasiewicz <andrzej.p at samsung.com>
This patch adds new videobuf2 memory allocator dedicated to devices that
supports IOMMU DMA mappings. A device with IOMMU module and a driver
with include/iommu.h compatible interface is required. This allocator
aquires memory with standard alloc_page() call and doesn't suffer from
memory fragmentation issues. The allocator support following page sizes:
4KiB, 64KiB, 1MiB and 16MiB to reduce iommu translation overhead.
Signed-off-by: Andrzej Pietrasiewicz <andrzej.p at samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park at samsung.com>
Signed-off-by: Marek Szyprowski <m.szyprowski at samsung.com>
---
drivers/media/video/Kconfig | 8 +-
drivers/media/video/Makefile | 1 +
drivers/media/video/videobuf2-dma-iommu.c | 762 +++++++++++++++++++++++++++++
include/media/videobuf2-dma-iommu.h | 48 ++
4 files changed, 818 insertions(+), 1 deletions(-)
create mode 100644 drivers/media/video/videobuf2-dma-iommu.c
create mode 100644 include/media/videobuf2-dma-iommu.h
diff --git a/drivers/media/video/Kconfig b/drivers/media/video/Kconfig
index 4498b94..40d7bcc 100644
--- a/drivers/media/video/Kconfig
+++ b/drivers/media/video/Kconfig
@@ -60,12 +60,18 @@ config VIDEOBUF2_VMALLOC
select VIDEOBUF2_MEMOPS
tristate
-
config VIDEOBUF2_DMA_SG
#depends on HAS_DMA
select VIDEOBUF2_CORE
select VIDEOBUF2_MEMOPS
tristate
+
+config VIDEOBUF2_DMA_IOMMU
+ select GENERIC_ALLOCATOR
+ select VIDEOBUF2_CORE
+ select VIDEOBUF2_MEMOPS
+ tristate
+
#
# Multimedia Video device configuration
#
diff --git a/drivers/media/video/Makefile b/drivers/media/video/Makefile
index ace5d8b..04136f6 100644
--- a/drivers/media/video/Makefile
+++ b/drivers/media/video/Makefile
@@ -118,6 +118,7 @@ obj-$(CONFIG_VIDEOBUF2_MEMOPS) += videobuf2-memops.o
obj-$(CONFIG_VIDEOBUF2_VMALLOC) += videobuf2-vmalloc.o
obj-$(CONFIG_VIDEOBUF2_DMA_CONTIG) += videobuf2-dma-contig.o
obj-$(CONFIG_VIDEOBUF2_DMA_SG) += videobuf2-dma-sg.o
+obj-$(CONFIG_VIDEOBUF2_DMA_IOMMU) += videobuf2-dma-iommu.o
obj-$(CONFIG_V4L2_MEM2MEM_DEV) += v4l2-mem2mem.o
diff --git a/drivers/media/video/videobuf2-dma-iommu.c b/drivers/media/video/videobuf2-dma-iommu.c
new file mode 100644
index 0000000..7ccb51a
--- /dev/null
+++ b/drivers/media/video/videobuf2-dma-iommu.c
@@ -0,0 +1,762 @@
+/*
+ * videobuf2-dma-iommu.c - IOMMU based memory allocator for videobuf2
+ *
+ * Copyright (C) 2011 Samsung Electronics
+ *
+ * Author: Andrzej Pietrasiewicz <andrzej.p at samsung.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/scatterlist.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+#include <linux/genalloc.h>
+#include <linux/device.h>
+#include <linux/iommu.h>
+#include <asm/cacheflush.h>
+#include <asm/page.h>
+
+#include <media/videobuf2-core.h>
+#include <media/videobuf2-memops.h>
+#include <media/videobuf2-dma-iommu.h>
+
+/*
+ * 17: single piece of memory (one bitmap entry) equals 128k,
+ * so by default the genalloc's bitmap occupies 4kB (one page
+ * for a number of architectures)
+ */
+#define VB2_DMA_IOMMU_PIECE_ORDER 17
+
+/* -1: use default node id to allocate gen_pool/gen_pool_chunk structure from */
+#define VB2_DMA_IOMMU_NODE_ID -1
+
+/*
+ * starting address of the virtual address space of the client device
+ * must not be zero
+ */
+#define VB2_DMA_IOMMU_MEM_BASE 0x30000000
+
+/* size of the virtual address space of the client device */
+#define VB2_DMA_IOMMU_MEM_SIZE 0x40000000
+
+struct vb2_dma_iommu_alloc_ctx {
+ struct device *dev;
+ struct gen_pool *pool;
+ unsigned int order;
+ struct iommu_domain *domain;
+};
+
+struct vb2_dma_iommu_desc {
+ unsigned long size;
+ unsigned int num_pages;
+ struct page **pages;
+ unsigned long *pg_map;
+ bool contig;
+};
+
+struct vb2_dma_iommu_buf {
+ unsigned long drv_addr;
+ unsigned long vaddr;
+
+ struct vb2_dma_iommu_desc info;
+ int offset;
+ atomic_t refcount;
+ int write;
+ struct vm_area_struct *vma;
+
+ struct vb2_vmarea_handler handler;
+
+ struct vb2_dma_iommu_alloc_ctx *ctx;
+};
+
+#define pages_4k(size) \
+ (((size) + PAGE_SIZE - 1) >> PAGE_SHIFT)
+
+#define pages_order(size, order) \
+ ((pages_4k(size) >> (order)) & 0xF)
+
+#define for_each_compound_page(bitmap, size, idx) \
+ for ((idx) = find_first_bit((bitmap), (size)); \
+ (idx) < (size); \
+ (idx) = find_next_bit((bitmap), (size), (idx) + 1))
+
+static int vb2_dma_iommu_max_order(unsigned long size)
+{
+ if ((size & 0xFFFF) == size) /* < 64k */
+ return 0;
+ if ((size & 0xFFFFF) == size) /* < 1M */
+ return 4;
+ if ((size & 0xFFFFFF) == size) /* < 16M */
+ return 8;
+ return 12; /* >= 16M */
+}
+
+/*
+ * num_pg must be 1, 16, 256 or 4096
+ */
+static int vb2_dma_iommu_pg_order(int num_pg)
+{
+ if (num_pg & 0x1)
+ return 0;
+ if (num_pg & 0x10)
+ return 4;
+ if (num_pg & 0x100)
+ return 8;
+ return 12;
+}
+
+/*
+ * size must be multiple of PAGE_SIZE
+ */
+static int vb2_dma_iommu_get_pages(struct vb2_dma_iommu_desc *desc,
+ unsigned long size)
+{
+ int order, num_pg_order, curr_4k_page, bit, max_order_ret;
+ unsigned long curr_size;
+
+ curr_4k_page = 0;
+ max_order_ret = 0;
+ curr_size = size; /* allocate (compound) pages until nothing remains */
+
+ order = vb2_dma_iommu_max_order(curr_size);
+ num_pg_order = pages_order(curr_size, order);
+
+ while (curr_size > 0 && order >= 0) {
+ int i, max_order;
+
+ printk(KERN_DEBUG "%s %d page(s) of %d order\n", __func__,
+ num_pg_order, order);
+
+ for (i = 0; i < num_pg_order; ++i) {
+ struct page *pg;
+ int j, compound_sz;
+
+ pg = alloc_pages(GFP_KERNEL | __GFP_ZERO | __GFP_COMP,
+ order);
+ if (!pg)
+ break;
+
+
+ if (order > max_order_ret)
+ max_order_ret = order;
+
+ compound_sz = 0x1 << order;
+ /* need to zero bitmap parts only for orders > 0 */
+ if (order)
+ bitmap_clear(desc->pg_map, curr_4k_page + 1,
+ compound_sz - 1);
+ for (j = 0; j < compound_sz; ++j)
+ desc->pages[curr_4k_page + j] = (pg + j);
+ curr_4k_page += compound_sz;
+ }
+ /*
+ * after the above for ends either way (loop condition not
+ * fulfilled/break) the i contains number of (compound) pages
+ * we managed to allocate
+ */
+ curr_size -= i * (PAGE_SIZE << order);
+ max_order = vb2_dma_iommu_max_order(curr_size);
+ /*
+ * max_order >= current order means that some allocations
+ * with order >= current order have failed, so we cannot attempt
+ * any greater orders again, we need to try an order smaller
+ * than the current order instead
+ */
+ if (max_order >= order)
+ max_order = order - 4;
+ order = max_order;
+ num_pg_order = pages_order(curr_size, order);
+ }
+
+ if (curr_size != 0)
+ goto get_pages_rollback;
+
+ return max_order_ret;
+
+get_pages_rollback:
+ for_each_compound_page(desc->pg_map, curr_4k_page, bit) {
+ int next_bit;
+
+ next_bit = find_next_bit(desc->pg_map, curr_4k_page, bit + 1);
+ order = vb2_dma_iommu_pg_order(next_bit - bit);
+ __free_pages(desc->pages[bit], order);
+ }
+
+ return -1;
+}
+
+static int vb2_dma_iommu_pg_sizes(struct vb2_dma_iommu_desc *desc)
+{
+ int i, order, max_order;
+
+ i = 0;
+ /* max order is 12, set to something greater */
+ order = 12 + 1;
+ max_order = 0;
+ while (i < desc->num_pages) {
+ unsigned long first, curr, next, curr_size;
+ int adjacent, j, new_order, num_pg_order;
+
+ first = 0;
+ j = i;
+ if (desc->contig) {
+ first = page_to_phys(desc->pages[0]);
+ adjacent = desc->num_pages;
+ } else {
+ curr = page_to_phys(desc->pages[i]);
+ if (order > 12)
+ first = curr;
+ while (++j < desc->num_pages) {
+ next = page_to_phys(desc->pages[j]);
+ if (curr + PAGE_SIZE != next)
+ break;
+ curr = next;
+ }
+ adjacent = j - i;
+ }
+ curr_size = adjacent << PAGE_SHIFT;
+ new_order = vb2_dma_iommu_max_order(curr_size);
+ /*
+ * by design decision max order in a sequence of blocks of
+ * zero-order pages must be monotonicaly decreasing
+ */
+ if (new_order > order) {
+ bitmap_fill(desc->pg_map, desc->num_pages);
+ return 0;
+ }
+ /*
+ * by design decision the first compound page of the buffer
+ * must be aligned according to its size
+ */
+ if (order > 12)
+ if (first & ((PAGE_SIZE << new_order) - 1)) {
+ bitmap_fill(desc->pg_map, desc->num_pages);
+ return 0;
+ }
+ order = new_order;
+ if (order > max_order)
+ max_order = order;
+ num_pg_order = pages_order(curr_size, order);
+ while (curr_size > 0) {
+ int compound_sz;
+
+ printk(KERN_DEBUG "%s %d page(s) of %d order\n",
+ __func__, num_pg_order, order);
+ compound_sz = 0x1 << order;
+ /* need to zero bitmap parts only for orders > 0 */
+ if (order)
+ for (j = 0; j < num_pg_order; ++j)
+ bitmap_clear(desc->pg_map,
+ i + j * compound_sz + 1,
+ compound_sz - 1);
+ i += num_pg_order * compound_sz;
+ curr_size -= num_pg_order * (PAGE_SIZE << order);
+ if (curr_size) {
+ order = vb2_dma_iommu_max_order(curr_size);
+ num_pg_order = pages_order(curr_size, order);
+ }
+ }
+ }
+ return max_order;
+}
+
+static int vb2_dma_iommu_map(struct iommu_domain *domain,
+ unsigned long drv_addr,
+ struct vb2_dma_iommu_desc *desc)
+{
+ int i, j, ret, order;
+ unsigned long pg_addr;
+
+ pg_addr = drv_addr;
+ ret = 0;
+ for_each_compound_page(desc->pg_map, desc->num_pages, i) {
+ int next_bit;
+ unsigned long paddr, compound_sz;
+
+ next_bit = find_next_bit(desc->pg_map, desc->num_pages, i + 1);
+ order = vb2_dma_iommu_pg_order(next_bit - i);
+ compound_sz = 0x1 << order << PAGE_SHIFT;
+ paddr = page_to_phys(desc->pages[i]);
+ ret = iommu_map(domain, pg_addr, paddr, order, 0);
+ if (ret < 0)
+ goto fail_map_area;
+ pg_addr += compound_sz;
+ }
+
+ return ret;
+
+fail_map_area:
+ pg_addr = drv_addr;
+ for_each_compound_page(desc->pg_map, i, j) {
+ int next_bit;
+
+ next_bit = find_next_bit(desc->pg_map, i, j + 1);
+ order = vb2_dma_iommu_pg_order(next_bit - j);
+ iommu_unmap(domain, pg_addr, order);
+ pg_addr += 0x1 << order << PAGE_SHIFT;
+ }
+ return ret;
+}
+
+static void vb2_dma_iommu_unmap(struct iommu_domain *domain,
+ unsigned long drv_addr,
+ struct vb2_dma_iommu_desc *desc)
+{
+ int i;
+
+ for_each_compound_page(desc->pg_map, desc->num_pages, i) {
+ int next_bit, order;
+
+ next_bit = find_next_bit(desc->pg_map, desc->num_pages, i + 1);
+ order = vb2_dma_iommu_pg_order(next_bit - i);
+ iommu_unmap(domain, drv_addr, order);
+ drv_addr += 0x1 << order << PAGE_SHIFT;
+ }
+}
+
+static void vb2_dma_iommu_put(void *buf_priv);
+
+static void *vb2_dma_iommu_alloc(void *alloc_ctx, unsigned long size)
+{
+ struct vb2_dma_iommu_alloc_ctx *ctx = alloc_ctx;
+ struct vb2_dma_iommu_buf *buf;
+ unsigned long size_pg, pg_map_size;
+ int i, ret, max_order;
+ void *rv;
+
+ BUG_ON(NULL == alloc_ctx);
+
+ rv = NULL;
+
+ buf = kzalloc(sizeof *buf, GFP_KERNEL);
+ if (!buf)
+ return ERR_PTR(-ENOMEM);
+
+ buf->ctx = ctx;
+ buf->info.size = size;
+ buf->info.num_pages = size_pg = pages_4k(size);
+
+ buf->info.pages = kzalloc(size_pg * sizeof(struct page *), GFP_KERNEL);
+ if (!buf->info.pages) {
+ rv = ERR_PTR(-ENOMEM);
+ goto buf_alloc_rollback;
+ }
+
+ pg_map_size = BITS_TO_LONGS(size_pg) * sizeof(unsigned long);
+ buf->info.pg_map = kzalloc(pg_map_size, GFP_KERNEL);
+ if (!buf->info.pg_map) {
+ rv = ERR_PTR(-ENOMEM);
+ goto pg_array_alloc_rollback;
+ }
+ bitmap_fill(buf->info.pg_map, size_pg);
+
+ max_order = vb2_dma_iommu_get_pages(&buf->info, size_pg * PAGE_SIZE);
+ if (max_order < 0) {
+ rv = ERR_PTR(-ENOMEM);
+ goto pg_map_alloc_rollback;
+ }
+
+ /* max_order is for number of pages; order of bytes: += 12 */
+ max_order += PAGE_SHIFT;
+ /* we need to keep the contract of vb2_dma_iommu_request */
+ if (max_order < ctx->order)
+ max_order = ctx->order;
+ buf->drv_addr = gen_pool_alloc_aligned(ctx->pool, size, max_order);
+ if (0 == buf->drv_addr) {
+ rv = ERR_PTR(-ENOMEM);
+ goto pages_alloc_rollback;
+ }
+
+ buf->handler.refcount = &buf->refcount;
+ buf->handler.put = vb2_dma_iommu_put;
+ buf->handler.arg = buf;
+
+ atomic_inc(&buf->refcount);
+
+ printk(KERN_DEBUG
+ "%s: Context 0x%lx mapping buffer of %d pages @0x%lx\n",
+ __func__ , (unsigned long)ctx, buf->info.num_pages,
+ buf->drv_addr);
+ ret = vb2_dma_iommu_map(ctx->domain, buf->drv_addr, &buf->info);
+ if (ret < 0) {
+ rv = ERR_PTR(ret);
+ goto gen_pool_alloc_rollback;
+ }
+
+ /*
+ * TODO: Ensure no one else flushes the cache later onto our memory
+ * which already contains important data.
+ * Perhaps find a better way to do it.
+ */
+ flush_cache_all();
+ outer_flush_all();
+ return buf;
+
+gen_pool_alloc_rollback:
+ gen_pool_free(ctx->pool, buf->drv_addr, size);
+
+pages_alloc_rollback:
+ for_each_compound_page(buf->info.pg_map, buf->info.num_pages, i) {
+ int next_bit;
+
+ next_bit = find_next_bit(buf->info.pg_map, buf->info.num_pages,
+ i + 1);
+ max_order = vb2_dma_iommu_pg_order(next_bit - i);
+ __free_pages(buf->info.pages[i], max_order);
+ }
+
+pg_map_alloc_rollback:
+ kfree(buf->info.pg_map);
+
+pg_array_alloc_rollback:
+ kfree(buf->info.pages);
+
+buf_alloc_rollback:
+ kfree(buf);
+ return rv;
+}
+
+static void vb2_dma_iommu_put(void *buf_priv)
+{
+ struct vb2_dma_iommu_buf *buf = buf_priv;
+
+ if (atomic_dec_and_test(&buf->refcount)) {
+ int i, order;
+
+ printk(KERN_DEBUG
+ "%s: Context 0x%lx releasing buffer of %d pages @0x%lx\n",
+ __func__, (unsigned long)buf->ctx, buf->info.num_pages,
+ buf->drv_addr);
+
+ vb2_dma_iommu_unmap(buf->ctx->domain, buf->drv_addr,
+ &buf->info);
+ if (buf->vaddr)
+ vm_unmap_ram((void *)buf->vaddr, buf->info.num_pages);
+
+ gen_pool_free(buf->ctx->pool, buf->drv_addr, buf->info.size);
+ for_each_compound_page(buf->info.pg_map,
+ buf->info.num_pages, i) {
+ int next_bit;
+
+ next_bit = find_next_bit(buf->info.pg_map,
+ buf->info.num_pages, i + 1);
+ order = vb2_dma_iommu_pg_order(next_bit - i);
+ __free_pages(buf->info.pages[i], order);
+ }
+ kfree(buf->info.pg_map);
+ kfree(buf->info.pages);
+ kfree(buf);
+ }
+}
+
+static void *vb2_dma_iommu_get_userptr(void *alloc_ctx, unsigned long vaddr,
+ unsigned long size, int write)
+{
+ struct vb2_dma_iommu_alloc_ctx *ctx = alloc_ctx;
+ struct vb2_dma_iommu_buf *buf;
+ unsigned long first, last, size_pg, pg_map_size;
+ int num_pages_from_user, max_order, ret;
+ void *rv;
+
+ BUG_ON(NULL == alloc_ctx);
+
+ rv = NULL;
+
+ buf = kzalloc(sizeof *buf, GFP_KERNEL);
+ if (!buf)
+ return ERR_PTR(-ENOMEM);
+
+ buf->ctx = ctx;
+ buf->info.size = size;
+ /*
+ * Page numbers of the first and the last byte of the buffer
+ */
+ first = vaddr >> PAGE_SHIFT;
+ last = (vaddr + size - 1) >> PAGE_SHIFT;
+ buf->info.num_pages = size_pg = last - first + 1;
+ buf->offset = vaddr & ~PAGE_MASK;
+ buf->write = write;
+
+ buf->info.pages = kzalloc(size_pg * sizeof(struct page *), GFP_KERNEL);
+ if (!buf->info.pages) {
+ rv = ERR_PTR(-ENOMEM);
+ goto buf_alloc_rollback;
+ }
+
+ pg_map_size = BITS_TO_LONGS(size_pg) * sizeof(unsigned long);
+ buf->info.pg_map = kzalloc(pg_map_size, GFP_KERNEL);
+ if (!buf->info.pg_map) {
+ rv = ERR_PTR(-ENOMEM);
+ goto pg_array_alloc_rollback;
+ }
+ bitmap_fill(buf->info.pg_map, size_pg);
+
+ num_pages_from_user = vb2_get_user_pages(vaddr, buf->info.num_pages,
+ buf->info.pages, write,
+ &buf->vma);
+
+ /* do not accept partial success */
+ if (num_pages_from_user >= 0 && num_pages_from_user < size_pg) {
+ rv = ERR_PTR(-EFAULT);
+ goto get_user_pages_rollback;
+ }
+
+ if (num_pages_from_user < 0) {
+ struct vm_area_struct *vma;
+ int i;
+ dma_addr_t paddr;
+
+ paddr = 0;
+ ret = vb2_get_contig_userptr(vaddr, size, &vma, &paddr);
+ if (ret) {
+ rv = ERR_PTR(ret);
+ goto get_user_pages_rollback;
+ }
+
+ buf->vma = vma;
+ buf->info.contig = true;
+ paddr -= buf->offset;
+
+ for (i = 0; i < size_pg; paddr += PAGE_SIZE, ++i)
+ buf->info.pages[i] = phys_to_page(paddr);
+ }
+ max_order = vb2_dma_iommu_pg_sizes(&buf->info);
+
+ /* max_order is for number of pages; order of bytes: += 12 */
+ max_order += PAGE_SHIFT;
+ /* we need to keep the contract of vb2_dma_iommu_request */
+ if (max_order < ctx->order)
+ max_order = ctx->order;
+
+ buf->drv_addr = gen_pool_alloc_aligned(ctx->pool, size, max_order);
+ if (0 == buf->drv_addr) {
+ rv = ERR_PTR(-ENOMEM);
+ goto get_user_pages_rollback;
+ }
+ printk(KERN_DEBUG
+ "%s: Context 0x%lx mapping buffer of %ld user pages @0x%lx\n",
+ __func__ , (unsigned long)ctx, size_pg, buf->drv_addr);
+ ret = vb2_dma_iommu_map(ctx->domain, buf->drv_addr, &buf->info);
+ if (ret < 0) {
+ rv = ERR_PTR(ret);
+ goto gen_pool_alloc_rollback;
+ }
+
+ return buf;
+
+gen_pool_alloc_rollback:
+ gen_pool_free(ctx->pool, buf->drv_addr, size);
+
+get_user_pages_rollback:
+ while (--num_pages_from_user >= 0)
+ put_page(buf->info.pages[num_pages_from_user]);
+ if (buf->vma)
+ vb2_put_vma(buf->vma);
+ kfree(buf->info.pg_map);
+
+pg_array_alloc_rollback:
+ kfree(buf->info.pages);
+
+buf_alloc_rollback:
+ kfree(buf);
+ return rv;
+}
+
+/*
+ * @put_userptr: inform the allocator that a USERPTR buffer will no longer
+ * be used
+ */
+static void vb2_dma_iommu_put_userptr(void *buf_priv)
+{
+ struct vb2_dma_iommu_buf *buf = buf_priv;
+ int i;
+
+ printk(KERN_DEBUG
+ "%s: Context 0x%lx releasing buffer of %d user pages @0x%lx\n",
+ __func__, (unsigned long)buf->ctx, buf->info.num_pages,
+ buf->drv_addr);
+ vb2_dma_iommu_unmap(buf->ctx->domain, buf->drv_addr, &buf->info);
+ if (buf->vaddr)
+ vm_unmap_ram((void *)buf->vaddr, buf->info.num_pages);
+
+ gen_pool_free(buf->ctx->pool, buf->drv_addr, buf->info.size);
+
+ if (buf->vma)
+ vb2_put_vma(buf->vma);
+
+ i = buf->info.num_pages;
+ if (!buf->info.contig) {
+ while (--i >= 0) {
+ if (buf->write)
+ set_page_dirty_lock(buf->info.pages[i]);
+ put_page(buf->info.pages[i]);
+ }
+ }
+ kfree(buf->info.pg_map);
+ kfree(buf->info.pages);
+ kfree(buf);
+}
+
+static void *vb2_dma_iommu_vaddr(void *buf_priv)
+{
+ struct vb2_dma_iommu_buf *buf = buf_priv;
+
+ BUG_ON(!buf);
+
+ if (!buf->vaddr)
+ buf->vaddr = (unsigned long)vm_map_ram(buf->info.pages,
+ buf->info.num_pages,
+ -1,
+ pgprot_dmacoherent(PAGE_KERNEL));
+
+ /* add offset in case userptr is not page-aligned */
+ return (void *)(buf->vaddr + buf->offset);
+}
+
+static unsigned int vb2_dma_iommu_num_users(void *buf_priv)
+{
+ struct vb2_dma_iommu_buf *buf = buf_priv;
+
+ return atomic_read(&buf->refcount);
+}
+
+static int vb2_dma_iommu_mmap(void *buf_priv, struct vm_area_struct *vma)
+{
+ struct vb2_dma_iommu_buf *buf = buf_priv;
+ int ret;
+
+ if (!buf) {
+ printk(KERN_ERR "No memory to map\n");
+ return -EINVAL;
+ }
+
+ vma->vm_page_prot = pgprot_dmacoherent(vma->vm_page_prot);
+
+ ret = vb2_insert_pages(vma, buf->info.pages);
+ if (ret)
+ return ret;
+
+ /*
+ * Use common vm_area operations to track buffer refcount.
+ */
+ vma->vm_private_data = &buf->handler;
+ vma->vm_ops = &vb2_common_vm_ops;
+
+ vma->vm_ops->open(vma);
+
+ return 0;
+}
+
+static void *vb2_dma_iommu_cookie(void *buf_priv)
+{
+ struct vb2_dma_iommu_buf *buf = buf_priv;
+
+ return (void *)buf->drv_addr + buf->offset;
+}
+
+const struct vb2_mem_ops vb2_dma_iommu_memops = {
+ .alloc = vb2_dma_iommu_alloc,
+ .put = vb2_dma_iommu_put,
+ .get_userptr = vb2_dma_iommu_get_userptr,
+ .put_userptr = vb2_dma_iommu_put_userptr,
+ .vaddr = vb2_dma_iommu_vaddr,
+ .mmap = vb2_dma_iommu_mmap,
+ .num_users = vb2_dma_iommu_num_users,
+ .cookie = vb2_dma_iommu_cookie,
+};
+EXPORT_SYMBOL_GPL(vb2_dma_iommu_memops);
+
+void *vb2_dma_iommu_init(struct device *dev, struct device *iommu_dev,
+ struct vb2_dma_iommu_request *iommu_req)
+{
+ struct vb2_dma_iommu_alloc_ctx *ctx;
+ unsigned long mem_base, mem_size;
+ int align_order;
+
+ ctx = kzalloc(sizeof *ctx, GFP_KERNEL);
+ if (!ctx)
+ return ERR_PTR(-ENOMEM);
+
+ align_order = VB2_DMA_IOMMU_PIECE_ORDER;
+ mem_base = VB2_DMA_IOMMU_MEM_BASE;
+ mem_size = VB2_DMA_IOMMU_MEM_SIZE;
+
+ if (iommu_req) {
+ if (iommu_req->align_order)
+ align_order = iommu_req->align_order;
+ if (iommu_req->mem_base)
+ mem_base = iommu_req->mem_base;
+ if (iommu_req->mem_size)
+ mem_size = iommu_req->mem_size;
+ }
+
+ ctx->order = align_order;
+ ctx->pool = gen_pool_create(align_order, VB2_DMA_IOMMU_NODE_ID);
+
+ if (!ctx->pool)
+ goto pool_alloc_fail;
+
+ if (gen_pool_add(ctx->pool, mem_base, mem_size, VB2_DMA_IOMMU_NODE_ID))
+ goto chunk_add_fail;
+
+ ctx->domain = iommu_domain_alloc();
+ if (!ctx->domain) {
+ dev_err(dev, "IOMMU domain alloc failed\n");
+ goto chunk_add_fail;
+ }
+
+ ctx->dev = iommu_dev;
+
+ return ctx;
+
+chunk_add_fail:
+ gen_pool_destroy(ctx->pool);
+pool_alloc_fail:
+ kfree(ctx);
+ return ERR_PTR(-ENOMEM);
+}
+EXPORT_SYMBOL_GPL(vb2_dma_iommu_init);
+
+void vb2_dma_iommu_cleanup(void *alloc_ctx)
+{
+ struct vb2_dma_iommu_alloc_ctx *ctx = alloc_ctx;
+
+ BUG_ON(NULL == alloc_ctx);
+
+ iommu_domain_free(ctx->domain);
+ gen_pool_destroy(ctx->pool);
+ kfree(alloc_ctx);
+}
+EXPORT_SYMBOL_GPL(vb2_dma_iommu_cleanup);
+
+int vb2_dma_iommu_enable(void *alloc_ctx)
+{
+ struct vb2_dma_iommu_alloc_ctx *ctx = alloc_ctx;
+
+ BUG_ON(NULL == alloc_ctx);
+
+ return iommu_attach_device(ctx->domain, ctx->dev);
+}
+EXPORT_SYMBOL_GPL(vb2_dma_iommu_enable);
+
+int vb2_dma_iommu_disable(void *alloc_ctx)
+{
+ struct vb2_dma_iommu_alloc_ctx *ctx = alloc_ctx;
+
+ BUG_ON(NULL == alloc_ctx);
+
+ iommu_detach_device(ctx->domain, ctx->dev);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(vb2_dma_iommu_disable);
+
+MODULE_DESCRIPTION("iommu memory handling routines for videobuf2");
+MODULE_AUTHOR("Andrzej Pietrasiewicz");
+MODULE_LICENSE("GPL");
diff --git a/include/media/videobuf2-dma-iommu.h b/include/media/videobuf2-dma-iommu.h
new file mode 100644
index 0000000..02d3b14
--- /dev/null
+++ b/include/media/videobuf2-dma-iommu.h
@@ -0,0 +1,48 @@
+/*
+ * videobuf2-dma-iommu.h - IOMMU based memory allocator for videobuf2
+ *
+ * Copyright (C) 2011 Samsung Electronics
+ *
+ * Author: Andrzej Pietrasiewicz <andrzej.p at samsung.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_DMA_IOMMU_H
+#define _MEDIA_VIDEOBUF2_DMA_IOMMU_H
+
+#include <media/videobuf2-core.h>
+
+struct device;
+
+struct vb2_dma_iommu_request {
+ /* mem_base and mem_size both 0 => use allocator's default */
+ unsigned long mem_base;
+ unsigned long mem_size;
+ /*
+ * align_order 0 => use allocator's default
+ * 0 < align_order < PAGE_SHIFT => rounded to PAGE_SHIFT by allocator
+ */
+ int align_order;
+};
+
+static inline unsigned long vb2_dma_iommu_plane_addr(
+ struct vb2_buffer *vb, unsigned int plane_no)
+{
+ return (unsigned long)vb2_plane_cookie(vb, plane_no);
+}
+
+extern const struct vb2_mem_ops vb2_dma_iommu_memops;
+
+void *vb2_dma_iommu_init(struct device *dev, struct device *iommu_dev,
+ struct vb2_dma_iommu_request *req);
+
+void vb2_dma_iommu_cleanup(void *alloc_ctx);
+
+int vb2_dma_iommu_enable(void *alloc_ctx);
+
+int vb2_dma_iommu_disable(void *alloc_ctx);
+
+#endif
--
1.7.1.569.g6f426
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