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dma-direct: provide page based alloc/free helpers

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Some architectures support remapping highmem into DMA coherent
allocations.  To use the common code for them we need variants of
dma_direct_{alloc,free}_pages that do not use kernel virtual addresses.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
This commit is contained in:
Christoph Hellwig
2018-11-04 17:27:56 +01:00
parent c9d76d0655
commit b18814e767
2 changed files with 25 additions and 10 deletions
Download Patch File Download Diff File Expand all files Collapse all files

3
include/linux/dma-direct.h
View File

@@ -67,6 +67,9 @@ void *dma_direct_alloc_pages(struct device *dev, size_t size,
dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs); dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs);
void dma_direct_free_pages(struct device *dev, size_t size, void *cpu_addr, void dma_direct_free_pages(struct device *dev, size_t size, void *cpu_addr,
dma_addr_t dma_addr, unsigned long attrs); dma_addr_t dma_addr, unsigned long attrs);
struct page *__dma_direct_alloc_pages(struct device *dev, size_t size,
dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs);
void __dma_direct_free_pages(struct device *dev, size_t size, struct page *page);
dma_addr_t dma_direct_map_page(struct device *dev, struct page *page, dma_addr_t dma_direct_map_page(struct device *dev, struct page *page,
unsigned long offset, size_t size, enum dma_data_direction dir, unsigned long offset, size_t size, enum dma_data_direction dir,
unsigned long attrs); unsigned long attrs);

32
kernel/dma/direct.c
View File

@@ -103,14 +103,13 @@ static bool dma_coherent_ok(struct device *dev, phys_addr_t phys, size_t size)
min_not_zero(dev->coherent_dma_mask, dev->bus_dma_mask); min_not_zero(dev->coherent_dma_mask, dev->bus_dma_mask);
} }
void *dma_direct_alloc_pages(struct device *dev, size_t size, struct page *__dma_direct_alloc_pages(struct device *dev, size_t size,
dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs) dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs)
{ {
unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT; unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
int page_order = get_order(size); int page_order = get_order(size);
struct page *page = NULL; struct page *page = NULL;
u64 phys_mask; u64 phys_mask;
void *ret;
if (attrs & DMA_ATTR_NO_WARN) if (attrs & DMA_ATTR_NO_WARN)
gfp |= __GFP_NOWARN; gfp |= __GFP_NOWARN;
@@ -150,11 +149,22 @@ again:
} }
} }
return page;
}
void *dma_direct_alloc_pages(struct device *dev, size_t size,
dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs)
{
struct page *page;
void *ret;
page = __dma_direct_alloc_pages(dev, size, dma_handle, gfp, attrs);
if (!page) if (!page)
return NULL; return NULL;
ret = page_address(page); ret = page_address(page);
if (force_dma_unencrypted()) { if (force_dma_unencrypted()) {
set_memory_decrypted((unsigned long)ret, 1 << page_order); set_memory_decrypted((unsigned long)ret, 1 << get_order(size));
*dma_handle = __phys_to_dma(dev, page_to_phys(page)); *dma_handle = __phys_to_dma(dev, page_to_phys(page));
} else { } else {
*dma_handle = phys_to_dma(dev, page_to_phys(page)); *dma_handle = phys_to_dma(dev, page_to_phys(page));
@@ -163,20 +173,22 @@ again:
return ret; return ret;
} }
/* void __dma_direct_free_pages(struct device *dev, size_t size, struct page *page)
* NOTE: this function must never look at the dma_addr argument, because we want {
* to be able to use it as a helper for iommu implementations as well. unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
*/
if (!dma_release_from_contiguous(dev, page, count))
__free_pages(page, get_order(size));
}
void dma_direct_free_pages(struct device *dev, size_t size, void *cpu_addr, void dma_direct_free_pages(struct device *dev, size_t size, void *cpu_addr,
dma_addr_t dma_addr, unsigned long attrs) dma_addr_t dma_addr, unsigned long attrs)
{ {
unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
unsigned int page_order = get_order(size); unsigned int page_order = get_order(size);
if (force_dma_unencrypted()) if (force_dma_unencrypted())
set_memory_encrypted((unsigned long)cpu_addr, 1 << page_order); set_memory_encrypted((unsigned long)cpu_addr, 1 << page_order);
if (!dma_release_from_contiguous(dev, virt_to_page(cpu_addr), count)) __dma_direct_free_pages(dev, size, virt_to_page(cpu_addr));
free_pages((unsigned long)cpu_addr, page_order);
} }
void *dma_direct_alloc(struct device *dev, size_t size, void *dma_direct_alloc(struct device *dev, size_t size,