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Commit 58edb515 authored by Nicolas Pitre's avatar Nicolas Pitre
Browse files

[ARM] make page_to_dma() highmem aware 



If a machine class has a custom __virt_to_bus() implementation then it
must provide a __arch_page_to_dma() implementation as well which is
_not_ based on page_address() to support highmem.

This patch fixes existing __arch_page_to_dma() and provide a default
implementation otherwise.  The default implementation for highmem is
based on __pfn_to_bus() which is defined only when no custom
__virt_to_bus() is provided by the machine class.

That leaves only ebsa110 and footbridge which cannot support highmem
until they provide their own __arch_page_to_dma() implementation.
But highmem support on those legacy platforms with limited memory is
certainly not a priority.

Signed-off-by: default avatarNicolas Pitre <nico@marvell.com>
parent 43377453

arch/arm/common/dmabounce.c

+7 −0
Original line number Diff line number Diff line
@@ -25,6 +25,7 @@ 
#include <linux/module.h>

#include <linux/init.h>

#include <linux/slab.h>

#include <linux/page-flags.h>

#include <linux/device.h>

#include <linux/dma-mapping.h>

#include <linux/dmapool.h>
@@ -349,6 +350,12 @@ dma_addr_t dma_map_page(struct device *dev, struct page *page, 


	BUG_ON(!valid_dma_direction(dir));



	if (PageHighMem(page)) {

		dev_err(dev, "DMA buffer bouncing of HIGHMEM pages "

			     "is not supported\n");

		return ~0;

	}



	return map_single(dev, page_address(page) + offset, size, dir);

}

EXPORT_SYMBOL(dma_map_page);

arch/arm/include/asm/dma-mapping.h

+10 −0
Original line number Diff line number Diff line
@@ -15,10 +15,20 @@ 
 * must not be used by drivers.

 */

#ifndef __arch_page_to_dma



#if !defined(CONFIG_HIGHMEM)

static inline dma_addr_t page_to_dma(struct device *dev, struct page *page)

{

	return (dma_addr_t)__virt_to_bus((unsigned long)page_address(page));

}

#elif defined(__pfn_to_bus)

static inline dma_addr_t page_to_dma(struct device *dev, struct page *page)

{

	return (dma_addr_t)__pfn_to_bus(page_to_pfn(page));

}

#else

#error "this machine class needs to define __arch_page_to_dma to use HIGHMEM"

#endif



static inline void *dma_to_virt(struct device *dev, dma_addr_t addr)

{

arch/arm/include/asm/memory.h

+1 −0
Original line number Diff line number Diff line
@@ -188,6 +188,7 @@ static inline void *phys_to_virt(unsigned long x) 
#ifndef __virt_to_bus

#define __virt_to_bus	__virt_to_phys

#define __bus_to_virt	__phys_to_virt

#define __pfn_to_bus(x)	((x) << PAGE_SHIFT)

#endif



static inline __deprecated unsigned long virt_to_bus(void *x)

arch/arm/mach-iop13xx/include/mach/memory.h

+4 −1
Original line number Diff line number Diff line
@@ -59,7 +59,10 @@ static inline unsigned long __lbus_to_virt(dma_addr_t x) 
	})



#define __arch_page_to_dma(dev, page)					\

	__arch_virt_to_dma(dev, page_address(page))

	({								\

		/* __is_lbus_virt() can never be true for RAM pages */	\

		(dma_addr_t)page_to_phys(page);				\

	})



#endif /* CONFIG_ARCH_IOP13XX */

#endif /* !ASSEMBLY */

arch/arm/mach-ks8695/include/mach/memory.h

+5 −1
Original line number Diff line number Diff line
@@ -35,7 +35,11 @@ extern struct bus_type platform_bus_type; 
					__phys_to_virt(x) : __bus_to_virt(x)); })

#define __arch_virt_to_dma(dev, x)	({ is_lbus_device(dev) ? \

					(dma_addr_t)__virt_to_phys(x) : (dma_addr_t)__virt_to_bus(x); })

#define __arch_page_to_dma(dev, x)	__arch_virt_to_dma(dev, page_address(x))

#define __arch_page_to_dma(dev, x)	\

	({ dma_addr_t __dma = page_to_phys(page); \

	   if (!is_lbus_device(dev)) \

		__dma = __dma - PHYS_OFFSET + KS8695_PCIMEM_PA; \

	   __dma; })



#endif