From: Santosh Shilimkar santosh.shilimkar@ti.com
Most of the kernel code assumes that max*pfn is maximum pfns because the physical start of memory is expected to be PFN0. Since this assumption is not true on ARM architectures, the meaning of max*pfn is number of memory pages. This is done to keep drivers happy which are making use of of these variable to calculate the dma bounce limit using dma_mask.
Now since we have a architecture override possibility for DMAable maximum pfns, lets make meaning of max*pfns as maximum pnfs on ARM as well.
Signed-off-by: Santosh Shilimkar santosh.shilimkar@ti.com Signed-off-by: Russell King rmk+kernel@arm.linux.org.uk --- arch/arm/include/asm/dma-mapping.h | 8 ++++++++ arch/arm/mm/init.c | 10 ++++------ 2 files changed, 12 insertions(+), 6 deletions(-)
diff --git a/arch/arm/include/asm/dma-mapping.h b/arch/arm/include/asm/dma-mapping.h index 5b579b9..863cd84 100644 --- a/arch/arm/include/asm/dma-mapping.h +++ b/arch/arm/include/asm/dma-mapping.h @@ -64,6 +64,7 @@ static inline dma_addr_t virt_to_dma(struct device *dev, void *addr) { return (dma_addr_t)__virt_to_bus((unsigned long)(addr)); } + #else static inline dma_addr_t pfn_to_dma(struct device *dev, unsigned long pfn) { @@ -86,6 +87,13 @@ static inline dma_addr_t virt_to_dma(struct device *dev, void *addr) } #endif
+/* The ARM override for dma_max_pfn() */ +static inline unsigned long dma_max_pfn(struct device *dev) +{ + return PHYS_PFN_OFFSET + dma_to_pfn(dev, *dev->dma_mask); +} +#define dma_max_pfn(dev) dma_max_pfn(dev) + /* * DMA errors are defined by all-bits-set in the DMA address. */ diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c index 8aab24f..d50533c 100644 --- a/arch/arm/mm/init.c +++ b/arch/arm/mm/init.c @@ -426,12 +426,10 @@ void __init bootmem_init(void) * This doesn't seem to be used by the Linux memory manager any * more, but is used by ll_rw_block. If we can get rid of it, we * also get rid of some of the stuff above as well. - * - * Note: max_low_pfn and max_pfn reflect the number of _pages_ in - * the system, not the maximum PFN. */ - max_low_pfn = max_low - PHYS_PFN_OFFSET; - max_pfn = max_high - PHYS_PFN_OFFSET; + min_low_pfn = min; + max_low_pfn = max_low; + max_pfn = max_high; }
/* @@ -537,7 +535,7 @@ static inline void free_area_high(unsigned long pfn, unsigned long end) static void __init free_highpages(void) { #ifdef CONFIG_HIGHMEM - unsigned long max_low = max_low_pfn + PHYS_PFN_OFFSET; + unsigned long max_low = max_low_pfn; struct memblock_region *mem, *res;
/* set highmem page free */