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Commit 6137e416 authored by Max Filippov's avatar Max Filippov
Browse files

xtensa: support DMA buffers in high memory 



If a DMA buffer is allocated in high memory and kernel mapping is
required use dma_common_contiguous_remap to map buffer to the vmalloc
region and dma_common_free_remap to unmap it.

Signed-off-by: default avatarMax Filippov <jcmvbkbc@gmail.com>
parent 6ac5a11d

arch/xtensa/kernel/pci-dma.c

+30 −10
Original line number Diff line number Diff line
@@ -16,6 +16,7 @@ 
 */



#include <linux/dma-contiguous.h>

#include <linux/dma-direct.h>

#include <linux/gfp.h>

#include <linux/highmem.h>

#include <linux/mm.h>
@@ -123,7 +124,7 @@ static void *xtensa_dma_alloc(struct device *dev, size_t size, 
			      unsigned long attrs)

{

	unsigned long ret;

	unsigned long uncached = 0;

	unsigned long uncached;

	unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT;

	struct page *page = NULL;
@@ -144,15 +145,27 @@ static void *xtensa_dma_alloc(struct device *dev, size_t size, 
	if (!page)

		return NULL;



	ret = (unsigned long)page_address(page);

	*handle = phys_to_dma(dev, page_to_phys(page));



	/* We currently don't support coherent memory outside KSEG */

#ifdef CONFIG_MMU

	if (PageHighMem(page)) {

		void *p;



		p = dma_common_contiguous_remap(page, size, VM_MAP,

						pgprot_noncached(PAGE_KERNEL),

						__builtin_return_address(0));

		if (!p) {

			if (!dma_release_from_contiguous(dev, page, count))

				__free_pages(page, get_order(size));

		}

		return p;

	}

#endif

	ret = (unsigned long)page_address(page);

	BUG_ON(ret < XCHAL_KSEG_CACHED_VADDR ||

	       ret > XCHAL_KSEG_CACHED_VADDR + XCHAL_KSEG_SIZE - 1);



	uncached = ret + XCHAL_KSEG_BYPASS_VADDR - XCHAL_KSEG_CACHED_VADDR;

	*handle = virt_to_bus((void *)ret);

	__invalidate_dcache_range(ret, size);



	return (void *)uncached;
@@ -161,13 +174,20 @@ static void *xtensa_dma_alloc(struct device *dev, size_t size, 
static void xtensa_dma_free(struct device *dev, size_t size, void *vaddr,

			    dma_addr_t dma_handle, unsigned long attrs)

{

	unsigned long addr = (unsigned long)vaddr +

		XCHAL_KSEG_CACHED_VADDR - XCHAL_KSEG_BYPASS_VADDR;

	struct page *page = virt_to_page(addr);

	unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT;



	BUG_ON(addr < XCHAL_KSEG_CACHED_VADDR ||

	       addr > XCHAL_KSEG_CACHED_VADDR + XCHAL_KSEG_SIZE - 1);

	unsigned long addr = (unsigned long)vaddr;

	struct page *page;



	if (addr >= XCHAL_KSEG_BYPASS_VADDR &&

	    addr - XCHAL_KSEG_BYPASS_VADDR < XCHAL_KSEG_SIZE) {

		addr += XCHAL_KSEG_CACHED_VADDR - XCHAL_KSEG_BYPASS_VADDR;

		page = virt_to_page(addr);

	} else {

#ifdef CONFIG_MMU

		dma_common_free_remap(vaddr, size, VM_MAP);

#endif

		page = pfn_to_page(PHYS_PFN(dma_to_phys(dev, dma_handle)));

	}



	if (!dma_release_from_contiguous(dev, page, count))

		__free_pages(page, get_order(size));