[PATCH 4/7] v4l: videobuf2: add IOMMU based DMA memory allocator
Marek Szyprowski
m.szyprowski at samsung.com
Tue Apr 5 10:06:47 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.
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 | 469 +++++++++++++++++++++++++++++
include/media/videobuf2-dma-iommu.h | 48 +++
4 files changed, 525 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..c208e6d
--- /dev/null
+++ b/drivers/media/video/videobuf2-dma-iommu.c
@@ -0,0 +1,469 @@
+/*
+ * 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;
+ struct iommu_domain *domain;
+};
+
+struct vb2_dma_iommu_desc {
+ unsigned long size;
+ unsigned int num_pages;
+ struct page **pages;
+};
+
+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;
+ bool contig;
+
+ struct vb2_vmarea_handler handler;
+
+ struct vb2_dma_iommu_alloc_ctx *ctx;
+};
+
+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 tmp;
+ int i, ret;
+
+ BUG_ON(NULL == alloc_ctx);
+
+ buf = kzalloc(sizeof *buf, GFP_KERNEL);
+ if (!buf)
+ return NULL;
+
+ buf->drv_addr = gen_pool_alloc(ctx->pool, size);
+ if (0 == buf->drv_addr)
+ goto gen_pool_alloc_fail;
+
+ buf->info.size = size;
+ buf->info.num_pages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
+ buf->ctx = ctx;
+ buf->info.pages = kzalloc(
+ buf->info.num_pages * sizeof(struct page *), GFP_KERNEL);
+ if (!buf->info.pages)
+ goto fail_pages_array_alloc;
+
+ for (i = 0; i < buf->info.num_pages; ++i) {
+ buf->info.pages[i] = alloc_page(GFP_KERNEL | __GFP_ZERO);
+ if (NULL == buf->info.pages[i])
+ goto fail_pages_alloc;
+ }
+
+ buf->handler.refcount = &buf->refcount;
+ buf->handler.put = vb2_dma_iommu_put;
+ buf->handler.arg = buf;
+
+ atomic_inc(&buf->refcount);
+
+ tmp = buf->drv_addr;
+ printk(KERN_DEBUG "%s: Map buffer of %d pages @0x%lx\n",
+ __func__ , buf->info.num_pages, buf->drv_addr);
+ for (i = 0; i < buf->info.num_pages; tmp += PAGE_SIZE, ++i) {
+ ret = iommu_map(ctx->domain, tmp, page_to_phys(buf->info.pages[i]), 0, 0);
+ if (ret < 0)
+ goto fail_map_area;
+ }
+
+
+ /*
+ * 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;
+
+fail_map_area:
+ tmp -= PAGE_SIZE;
+ while (--i >= 0) {
+ iommu_unmap(ctx->domain, tmp, 0);
+ tmp -= PAGE_SIZE;
+ }
+ i = buf->info.num_pages;
+fail_pages_alloc:
+ while (--i >= 0)
+ __free_page(buf->info.pages[i]);
+ kfree(buf->info.pages);
+
+fail_pages_array_alloc:
+ gen_pool_free(ctx->pool, buf->drv_addr, size);
+
+gen_pool_alloc_fail:
+ kfree(buf);
+ return NULL;
+}
+
+static void vb2_dma_iommu_put(void *buf_priv)
+{
+ struct vb2_dma_iommu_buf *buf = buf_priv;
+ int i;
+ unsigned long tmp;
+
+ if (atomic_dec_and_test(&buf->refcount)) {
+ tmp = buf->drv_addr;
+ printk(KERN_DEBUG "%s: Releasing buffer of %d pages @0x%lx\n",
+ __func__, buf->info.num_pages, buf->drv_addr);
+ for (i = 0; i < buf->info.num_pages; tmp += PAGE_SIZE, ++i)
+ iommu_unmap(buf->ctx->domain, tmp, 0);
+
+ i = buf->info.num_pages;
+ if (buf->vaddr)
+ vm_unmap_ram((void *)buf->vaddr, buf->info.num_pages);
+ while (--i >= 0)
+ __free_page(buf->info.pages[i]);
+ kfree(buf->info.pages);
+ gen_pool_free(buf->ctx->pool, buf->drv_addr, buf->info.size);
+ 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, tmp, tmp_phys;
+ int num_pages_from_user, ret;
+ void *rv = NULL;
+ int i = 0;
+
+ BUG_ON(NULL == alloc_ctx);
+
+ buf = kzalloc(sizeof *buf, GFP_KERNEL);
+ if (!buf)
+ return rv;
+
+ buf->drv_addr = gen_pool_alloc(ctx->pool, size);
+ if (0 == buf->drv_addr) {
+ rv = ERR_PTR(-ENOMEM);
+ goto userptr_gen_pool_alloc_fail;
+ }
+
+ buf->write = write;
+ buf->offset = vaddr & ~PAGE_MASK;
+ buf->info.size = size;
+ first = (vaddr & PAGE_MASK) >> PAGE_SHIFT;
+ last = ((vaddr + size - 1) & PAGE_MASK) >> PAGE_SHIFT;
+ buf->info.num_pages = last - first + 1;
+ buf->ctx = ctx;
+ buf->info.pages = kzalloc(buf->info.num_pages * sizeof(struct page *),
+ GFP_KERNEL);
+ if (!buf->info.pages) {
+ rv = ERR_PTR(-ENOMEM);
+ goto userptr_fail_pages_array_alloc;
+ }
+
+ num_pages_from_user = vb2_get_user_pages(vaddr, buf->info.num_pages,
+ buf->info.pages, write,
+ &buf->vma);
+
+ tmp = buf->drv_addr;
+ if (num_pages_from_user == buf->info.num_pages) {
+ printk(KERN_DEBUG "%s: Map buffer of %d pages @0x%lx\n",
+ __func__ , buf->info.num_pages, buf->drv_addr);
+ for (i = 0; i < buf->info.num_pages; tmp += PAGE_SIZE, ++i) {
+ ret = iommu_map(ctx->domain, tmp,
+ page_to_phys(buf->info.pages[i]), 0, 0);
+ if (ret)
+ goto userptr_fail_map_area;
+ }
+
+ return buf;
+ } else if (num_pages_from_user < 0) {
+ struct vm_area_struct *vma;
+ dma_addr_t paddr = 0;
+
+ ret = vb2_get_contig_userptr(vaddr, size, &vma, &paddr);
+
+ if (ret) {
+ rv = ERR_PTR(ret);
+ goto userptr_fail_get_contig;
+ }
+
+ buf->vma = vma;
+ buf->contig = true;
+
+ tmp_phys = paddr;
+ printk(KERN_DEBUG "%s: Map buffer of %d pages @0x%lx\n",
+ __func__ , buf->info.num_pages, buf->drv_addr);
+ for (i = 0; i < buf->info.num_pages; tmp += PAGE_SIZE,
+ tmp_phys += PAGE_SIZE, ++i) {
+ iommu_map(ctx->domain, tmp, tmp_phys, 0, 0);
+ if (ret)
+ goto userptr_fail_map_area;
+ }
+
+ return buf;
+ }
+ /* else fail */
+
+userptr_fail_map_area:
+ tmp -= PAGE_SIZE;
+ while (--i >= 0) {
+ iommu_unmap(ctx->domain, tmp, 0);
+ tmp -= PAGE_SIZE;
+ }
+ while (--num_pages_from_user >= 0)
+ put_page(buf->info.pages[num_pages_from_user]);
+ if (buf->vma)
+ vb2_put_vma(buf->vma);
+userptr_fail_get_contig:
+ kfree(buf->info.pages);
+
+userptr_fail_pages_array_alloc:
+ gen_pool_free(ctx->pool, buf->drv_addr, size);
+
+userptr_gen_pool_alloc_fail:
+ 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 = buf->info.num_pages;
+ unsigned long tmp;
+
+ printk(KERN_DEBUG "%s: Releasing buffer of %d pages @0x%lx\n",
+ __func__, buf->info.num_pages, buf->drv_addr);
+ if (buf->vaddr)
+ vm_unmap_ram((void *)buf->vaddr, buf->info.num_pages);
+
+ tmp = buf->drv_addr;
+ for (i = 0; i < buf->info.num_pages; tmp += PAGE_SIZE, ++i)
+ iommu_unmap(buf->ctx->domain, tmp, 0);
+
+ i = buf->info.num_pages;
+
+ if (buf->vma)
+ vb2_put_vma(buf->vma);
+ if (!buf->contig) {
+ while (--i >= 0) {
+ if (buf->write)
+ set_page_dirty_lock(buf->info.pages[i]);
+ put_page(buf->info.pages[i]);
+ }
+ }
+ kfree(buf->info.pages);
+ gen_pool_free(buf->ctx->pool, buf->drv_addr, buf->info.size);
+ 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_writecombine(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_writecombine(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->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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