[RFC 2/2] dma-mapping: Enable IOVA mapping with specific address
Hiroshi DOYU
hdoyu at nvidia.com
Fri May 18 02:10:27 EDT 2012
Enable IOVA (un)mapping at a specific IOVA address, independent of
allocating/freeing IOVA area, introducing the following
dma_(un)map_page_*at*() functions:
dma_map_page_at()
dma_unmap_page_at()
The above create a mapping between pre-allocated iova and a page, and
remov just a mapping, leaving iova itself allocated. At mapping, it
also checks if IOVA is already reserved or not.
There are the version with the prefix "arm_iommu_", and they are
exactly same as the above.
Signed-off-by: Hiroshi DOYU <hdoyu at nvidia.com>
---
arch/arm/include/asm/dma-iommu.h | 29 +++++++-
arch/arm/include/asm/dma-mapping.h | 1 +
arch/arm/mm/dma-mapping.c | 158 +++++++++++++++++++++++++++---------
3 files changed, 150 insertions(+), 38 deletions(-)
diff --git a/arch/arm/include/asm/dma-iommu.h b/arch/arm/include/asm/dma-iommu.h
index 2595928..99eba3d 100644
--- a/arch/arm/include/asm/dma-iommu.h
+++ b/arch/arm/include/asm/dma-iommu.h
@@ -30,9 +30,36 @@ void arm_iommu_release_mapping(struct dma_iommu_mapping *mapping);
int arm_iommu_attach_device(struct device *dev,
struct dma_iommu_mapping *mapping);
-dma_addr_t arm_iommu_alloc_iova(struct device *dev, size_t size);
+dma_addr_t arm_iommu_alloc_iova_at(struct device *dev, dma_addr_t addr,
+ size_t size);
+
+static inline dma_addr_t arm_iommu_alloc_iova(struct device *dev, size_t size)
+{
+ return arm_iommu_alloc_iova_at(dev, DMA_ANON_ADDR, size);
+}
void arm_iommu_free_iova(struct device *dev, dma_addr_t addr, size_t size);
+dma_addr_t arm_iommu_map_page_at(struct device *dev, struct page *page,
+ dma_addr_t addr, unsigned long offset, size_t size,
+ enum dma_data_direction dir, struct dma_attrs *attrs);
+
+static inline dma_addr_t dma_map_page_at(struct device *d, struct page *p,
+ dma_addr_t a, size_t o, size_t s,
+ enum dma_data_direction r)
+{
+ return arm_iommu_map_page_at(d, p, a, o, s, r, 0);
+}
+
+void arm_iommu_unmap_page_at(struct device *dev, dma_addr_t handle,
+ size_t size, enum dma_data_direction dir,
+ struct dma_attrs *attrs);
+
+static inline void dma_unmap_page_at(struct device *d, dma_addr_t a, size_t s,
+ enum dma_data_direction r)
+{
+ return arm_iommu_unmap_page_at(d, a, s, r, 0);
+}
+
#endif /* __KERNEL__ */
#endif
diff --git a/arch/arm/include/asm/dma-mapping.h b/arch/arm/include/asm/dma-mapping.h
index bbef15d..b73eb73 100644
--- a/arch/arm/include/asm/dma-mapping.h
+++ b/arch/arm/include/asm/dma-mapping.h
@@ -12,6 +12,7 @@
#include <asm/memory.h>
#define DMA_ERROR_CODE (~0)
+#define DMA_ANON_ADDR (~0)
extern struct dma_map_ops arm_dma_ops;
static inline struct dma_map_ops *get_dma_ops(struct device *dev)
diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index bca1715..b98e668 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -1013,48 +1013,65 @@ fs_initcall(dma_debug_do_init);
/* IOMMU */
-static inline dma_addr_t __alloc_iova(struct dma_iommu_mapping *mapping,
- size_t size)
+static dma_addr_t __alloc_iova_at(struct dma_iommu_mapping *mapping,
+ dma_addr_t iova, size_t size)
{
unsigned int order = get_order(size);
unsigned int align = 0;
- unsigned int count, start;
+ unsigned int count, start, orig = 0;
unsigned long flags;
+ bool anon = (iova == DMA_ANON_ADDR) ? true : false;
count = ((PAGE_ALIGN(size) >> PAGE_SHIFT) +
(1 << mapping->order) - 1) >> mapping->order;
- if (order > mapping->order)
+ if (anon && (order > mapping->order))
align = (1 << (order - mapping->order)) - 1;
spin_lock_irqsave(&mapping->lock, flags);
- start = bitmap_find_next_zero_area(mapping->bitmap, mapping->bits, 0,
- count, align);
- if (start > mapping->bits) {
- spin_unlock_irqrestore(&mapping->lock, flags);
- return DMA_ERROR_CODE;
- }
+ if (!anon)
+ orig = (iova - mapping->base) >> (mapping->order + PAGE_SHIFT);
+
+ start = bitmap_find_next_zero_area(mapping->bitmap, mapping->bits,
+ orig, count, align);
+ if (start > mapping->bits)
+ goto not_found;
+
+ if (!anon && (orig != start))
+ goto not_found;
bitmap_set(mapping->bitmap, start, count);
spin_unlock_irqrestore(&mapping->lock, flags);
return mapping->base + (start << (mapping->order + PAGE_SHIFT));
+
+not_found:
+ spin_unlock_irqrestore(&mapping->lock, flags);
+ return DMA_ERROR_CODE;
+}
+
+static inline dma_addr_t __alloc_iova(struct dma_iommu_mapping *mapping,
+ size_t size)
+{
+ return __alloc_iova_at(mapping, DMA_ANON_ADDR, size);
}
/**
- * arm_iommu_alloc_iova
+ * arm_iommu_alloc_iova_at
* @dev: valid struct device pointer
+ * @iova: iova address being requested. Set DMA_ANON_ADDR for arbitral
* @size: size of buffer to allocate
*
* Allocate IOVA address range
*/
-dma_addr_t arm_iommu_alloc_iova(struct device *dev, size_t size)
+dma_addr_t arm_iommu_alloc_iova_at(struct device *dev, dma_addr_t iova,
+ size_t size)
{
struct dma_iommu_mapping *mapping = dev->archdata.mapping;
- return __alloc_iova(mapping, size);
+ return __alloc_iova_at(mapping, iova, size);
}
-EXPORT_SYMBOL_GPL(arm_iommu_alloc_iova);
+EXPORT_SYMBOL_GPL(arm_iommu_alloc_iova_at);
static inline void __free_iova(struct dma_iommu_mapping *mapping,
dma_addr_t addr, size_t size)
@@ -1507,6 +1524,41 @@ void arm_iommu_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
__dma_page_cpu_to_dev(sg_page(s), s->offset, s->length, dir);
}
+static dma_addr_t __arm_iommu_map_page_at(struct device *dev, struct page *page,
+ dma_addr_t req, unsigned long offset, size_t size,
+ enum dma_data_direction dir, struct dma_attrs *attrs)
+{
+ struct dma_iommu_mapping *mapping = dev->archdata.mapping;
+ dma_addr_t dma_addr;
+ int ret, len = PAGE_ALIGN(size + offset);
+
+ if (!arch_is_coherent())
+ __dma_page_cpu_to_dev(page, offset, size, dir);
+
+ dma_addr = __alloc_iova_at(mapping, req, len);
+ if (dma_addr == DMA_ERROR_CODE) {
+ if (req == DMA_ANON_ADDR)
+ return DMA_ERROR_CODE;
+ /*
+ * Verified that iova(req) is reserved in advance if
+ * @req is specified.
+ */
+ dma_addr = req;
+ }
+
+ if (req != DMA_ANON_ADDR)
+ BUG_ON(dma_addr != req);
+
+ ret = iommu_map(mapping->domain, dma_addr, page_to_phys(page), len, 0);
+ if (ret < 0)
+ goto fail;
+
+ return dma_addr + offset;
+fail:
+ if (req == DMA_ANON_ADDR)
+ __free_iova(mapping, dma_addr, len);
+ return DMA_ERROR_CODE;
+}
/**
* arm_iommu_map_page
@@ -1522,25 +1574,47 @@ static dma_addr_t arm_iommu_map_page(struct device *dev, struct page *page,
unsigned long offset, size_t size, enum dma_data_direction dir,
struct dma_attrs *attrs)
{
- struct dma_iommu_mapping *mapping = dev->archdata.mapping;
- dma_addr_t dma_addr;
- int ret, len = PAGE_ALIGN(size + offset);
+ return __arm_iommu_map_page_at(dev, page, DMA_ANON_ADDR,
+ offset, size, dir, attrs);
+}
- if (!arch_is_coherent())
- __dma_page_cpu_to_dev(page, offset, size, dir);
+/**
+ * arm_iommu_map_page_at
+ * @dev: valid struct device pointer
+ * @page: page that buffer resides in
+ * @req: iova address being requested. Set DMA_ANON_ADDR for arbitral
+ * @offset: offset into page for start of buffer
+ * @size: size of buffer to map
+ * @dir: DMA transfer direction
+ *
+ * The version with a specified iova address of arm_iommu_map_page().
+ */
+dma_addr_t arm_iommu_map_page_at(struct device *dev, struct page *page,
+ dma_addr_t req, unsigned long offset, size_t size,
+ enum dma_data_direction dir, struct dma_attrs *attrs)
+{
+ return __arm_iommu_map_page_at(dev, page, req, offset, size, dir,
+ attrs);
+}
+EXPORT_SYMBOL_GPL(arm_iommu_map_page_at);
- dma_addr = __alloc_iova(mapping, len);
- if (dma_addr == DMA_ERROR_CODE)
- return dma_addr;
+static inline int __arm_iommu_unmap_page(struct device *dev, dma_addr_t handle,
+ size_t size, enum dma_data_direction dir,
+ struct dma_attrs *attrs)
+{
+ dma_addr_t iova = handle & PAGE_MASK;
+ struct page *page = phys_to_page(iommu_iova_to_phys(mapping->domain, iova));
+ int offset = handle & ~PAGE_MASK;
+ int len = PAGE_ALIGN(size + offset);
- ret = iommu_map(mapping->domain, dma_addr, page_to_phys(page), len, 0);
- if (ret < 0)
- goto fail;
+ if (!iova)
+ return -EINVAL;
- return dma_addr + offset;
-fail:
- __free_iova(mapping, dma_addr, len);
- return DMA_ERROR_CODE;
+ if (!arch_is_coherent())
+ __dma_page_dev_to_cpu(page, offset, size, dir);
+
+ iommu_unmap(mapping->domain, iova, len);
+ return 0;
}
/**
@@ -1558,20 +1632,30 @@ static void arm_iommu_unmap_page(struct device *dev, dma_addr_t handle,
{
struct dma_iommu_mapping *mapping = dev->archdata.mapping;
dma_addr_t iova = handle & PAGE_MASK;
- struct page *page = phys_to_page(iommu_iova_to_phys(mapping->domain, iova));
- int offset = handle & ~PAGE_MASK;
int len = PAGE_ALIGN(size + offset);
- if (!iova)
+ if (__arm_iommu_unmap_page(dev, handle, size, dir, attrs))
return;
-
- if (!arch_is_coherent())
- __dma_page_dev_to_cpu(page, offset, size, dir);
-
- iommu_unmap(mapping->domain, iova, len);
__free_iova(mapping, iova, len);
}
+/**
+ * arm_iommu_unmap_page_at
+ * @dev: valid struct device pointer
+ * @handle: DMA address of buffer
+ * @size: size of buffer (same as passed to dma_map_page)
+ * @dir: DMA transfer direction (same as passed to dma_map_page)
+ *
+ * The version without freeing iova of arm_iommu_unmap_page().
+ */
+void arm_iommu_unmap_page_at(struct device *dev, dma_addr_t handle,
+ size_t size, enum dma_data_direction dir,
+ struct dma_attrs *attrs)
+{
+ __arm_iommu_unmap_page(dev, handle, size, dir, attrs);
+}
+EXPORT_SYMBOL_GPL(arm_iommu_unmap_page_at);
+
static void arm_iommu_sync_single_for_cpu(struct device *dev,
dma_addr_t handle, size_t size, enum dma_data_direction dir)
{
--
1.7.5.4
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