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[ARM] make page_to_dma() highmem aware

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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: Nicolas Pitre <nico@marvell.com>
This commit is contained in:
Nicolas Pitre
2008-09-09 15:54:13 -04:00
parent 43377453af
commit 58edb51572
6 changed files with 32 additions and 5 deletions
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10
arch/arm/include/asm/dma-mapping.h
View File

@ -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)
{