From: Grygorii Strashko <[email protected]>

In most of cases DMA addresses can be performed using offset value of
 Bus address space relatively to physical address space as following:

PFN->DMA:
 __pfn_to_phys(pfn + [-]dma_pfn_offset)

DMA->PFN:
 __phys_to_pfn(dma_addr) + [-]dma_pfn_offset

Cc: Greg Kroah-Hartman <[email protected]>
Cc: Russell King <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Cc: Olof Johansson <[email protected]>
Cc: Grant Likely <[email protected]>
Cc: Rob Herring <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Linus Walleij <[email protected]>
Signed-off-by: Grygorii Strashko <[email protected]>
Signed-off-by: Santosh Shilimkar <[email protected]>
---
 arch/arm/include/asm/dma-mapping.h |   21 +++++++++++++++++----
 1 file changed, 17 insertions(+), 4 deletions(-)

diff --git a/arch/arm/include/asm/dma-mapping.h 
b/arch/arm/include/asm/dma-mapping.h
index e701a4d..424fda9 100644
--- a/arch/arm/include/asm/dma-mapping.h
+++ b/arch/arm/include/asm/dma-mapping.h
@@ -58,22 +58,35 @@ static inline int dma_set_mask(struct device *dev, u64 mask)
 #ifndef __arch_pfn_to_dma
 static inline dma_addr_t pfn_to_dma(struct device *dev, unsigned long pfn)
 {
-       return (dma_addr_t)__pfn_to_bus(pfn);
+       if (!dev)
+               return (dma_addr_t)__pfn_to_bus(pfn);
+       else
+               return (dma_addr_t)__pfn_to_bus(pfn - dev->dma_pfn_offset);
 }
 
 static inline unsigned long dma_to_pfn(struct device *dev, dma_addr_t addr)
 {
-       return __bus_to_pfn(addr);
+       if (!dev)
+               return __bus_to_pfn(addr);
+       else
+               return __bus_to_pfn(addr) + dev->dma_pfn_offset;
 }
 
 static inline void *dma_to_virt(struct device *dev, dma_addr_t addr)
 {
-       return (void *)__bus_to_virt((unsigned long)addr);
+       if (!dev)
+               return (void *)__bus_to_virt((unsigned long)addr);
+       else
+               return (void *)__bus_to_virt(__pfn_to_bus(dma_to_pfn(dev, 
addr)));
 }
 
 static inline dma_addr_t virt_to_dma(struct device *dev, void *addr)
 {
-       return (dma_addr_t)__virt_to_bus((unsigned long)(addr));
+       if (!dev)
+               return (dma_addr_t)__virt_to_bus((unsigned long)(addr));
+       else
+               return pfn_to_dma(dev,
+                               __bus_to_pfn(__virt_to_bus((unsigned 
long)(addr))));
 }
 
 #else
-- 
1.7.9.5

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