ARM: dma: Use dma_pfn_offset for dma address translation
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
Thanks to Russell King for suggesting the optimised macro's for
conversion.
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Olof Johansson <olof@lixom.net>
Cc: Grant Likely <grant.likely@linaro.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
diff --git a/arch/arm/include/asm/dma-mapping.h b/arch/arm/include/asm/dma-mapping.h
index e701a4d..b0c79fd 100644
--- a/arch/arm/include/asm/dma-mapping.h
+++ b/arch/arm/include/asm/dma-mapping.h
@@ -58,21 +58,37 @@
#ifndef __arch_pfn_to_dma
static inline dma_addr_t pfn_to_dma(struct device *dev, unsigned long pfn)
{
+ if (dev)
+ pfn -= dev->dma_pfn_offset;
return (dma_addr_t)__pfn_to_bus(pfn);
}
static inline unsigned long dma_to_pfn(struct device *dev, dma_addr_t addr)
{
- return __bus_to_pfn(addr);
+ unsigned long pfn = __bus_to_pfn(addr);
+
+ if (dev)
+ pfn += dev->dma_pfn_offset;
+
+ return pfn;
}
static inline void *dma_to_virt(struct device *dev, dma_addr_t addr)
{
+ if (dev) {
+ unsigned long pfn = dma_to_pfn(dev, addr);
+
+ return phys_to_virt(__pfn_to_phys(pfn));
+ }
+
return (void *)__bus_to_virt((unsigned long)addr);
}
static inline dma_addr_t virt_to_dma(struct device *dev, void *addr)
{
+ if (dev)
+ return pfn_to_dma(dev, virt_to_pfn(addr));
+
return (dma_addr_t)__virt_to_bus((unsigned long)(addr));
}