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Commit c7ca9fe1 authored by Max Filippov's avatar Max Filippov
Browse files

xtensa: support DMA to high memory 



- don't bugcheck if high memory page is passed to xtensa_map_page;
- turn empty dcache flush macros into functions so that they could be
  passed as function parameters;
- use kmap_atomic to map high memory pages for cache invalidation/
  flushing performed by xtensa_sync_single_for_{cpu,device}.

Signed-off-by: default avatarMax Filippov <jcmvbkbc@gmail.com>
parent e2b31f75

arch/xtensa/include/asm/cacheflush.h

+8 −3
Original line number Diff line number Diff line
@@ -55,8 +55,13 @@ extern void __flush_dcache_range(unsigned long, unsigned long); 
extern void __flush_invalidate_dcache_page(unsigned long);

extern void __flush_invalidate_dcache_range(unsigned long, unsigned long);

#else

# define __flush_dcache_range(p,s)		do { } while(0)

# define __flush_dcache_page(p)			do { } while(0)

static inline void __flush_dcache_page(unsigned long va)

{

}

static inline void __flush_dcache_range(unsigned long va, unsigned long sz)

{

}

# define __flush_invalidate_dcache_all()	__invalidate_dcache_all()

# define __flush_invalidate_dcache_page(p)	__invalidate_dcache_page(p)

# define __flush_invalidate_dcache_range(p,s)	__invalidate_dcache_range(p,s)

#endif

arch/xtensa/kernel/pci-dma.c

+31 −14
Original line number Diff line number Diff line
@@ -15,14 +15,15 @@ 
 * Joe Taylor <joe@tensilica.com, joetylr@yahoo.com>

 */



#include <linux/types.h>

#include <linux/mm.h>

#include <linux/string.h>

#include <linux/pci.h>

#include <linux/gfp.h>

#include <linux/highmem.h>

#include <linux/mm.h>

#include <linux/module.h>

#include <asm/io.h>

#include <linux/pci.h>

#include <linux/string.h>

#include <linux/types.h>

#include <asm/cacheflush.h>

#include <asm/io.h>



void dma_cache_sync(struct device *dev, void *vaddr, size_t size,

		    enum dma_data_direction dir)
@@ -47,17 +48,36 @@ void dma_cache_sync(struct device *dev, void *vaddr, size_t size, 
}

EXPORT_SYMBOL(dma_cache_sync);



static void do_cache_op(dma_addr_t dma_handle, size_t size,

			void (*fn)(unsigned long, unsigned long))

{

	unsigned long off = dma_handle & (PAGE_SIZE - 1);

	unsigned long pfn = PFN_DOWN(dma_handle);

	struct page *page = pfn_to_page(pfn);



	if (!PageHighMem(page))

		fn((unsigned long)bus_to_virt(dma_handle), size);

	else

		while (size > 0) {

			size_t sz = min_t(size_t, size, PAGE_SIZE - off);

			void *vaddr = kmap_atomic(page);



			fn((unsigned long)vaddr + off, sz);

			kunmap_atomic(vaddr);

			off = 0;

			++page;

			size -= sz;

		}

}



static void xtensa_sync_single_for_cpu(struct device *dev,

				       dma_addr_t dma_handle, size_t size,

				       enum dma_data_direction dir)

{

	void *vaddr;



	switch (dir) {

	case DMA_BIDIRECTIONAL:

	case DMA_FROM_DEVICE:

		vaddr = bus_to_virt(dma_handle);

		__invalidate_dcache_range((unsigned long)vaddr, size);

		do_cache_op(dma_handle, size, __invalidate_dcache_range);

		break;



	case DMA_NONE:
@@ -73,13 +93,11 @@ static void xtensa_sync_single_for_device(struct device *dev, 
					  dma_addr_t dma_handle, size_t size,

					  enum dma_data_direction dir)

{

	void *vaddr;



	switch (dir) {

	case DMA_BIDIRECTIONAL:

	case DMA_TO_DEVICE:

		vaddr = bus_to_virt(dma_handle);

		__flush_dcache_range((unsigned long)vaddr, size);

		if (XCHAL_DCACHE_IS_WRITEBACK)

			do_cache_op(dma_handle, size, __flush_dcache_range);

		break;



	case DMA_NONE:
@@ -171,7 +189,6 @@ static dma_addr_t xtensa_map_page(struct device *dev, struct page *page, 
{

	dma_addr_t dma_handle = page_to_phys(page) + offset;



	BUG_ON(PageHighMem(page));

	xtensa_sync_single_for_device(dev, dma_handle, size, dir);

	return dma_handle;

}