[PATCH v3 5/7] ARM: dma: Use dma_pfn_offset for dma address translation

Santosh Shilimkar
2014-04-24T15:32:58Z

From: Grygorii Strashko <grygorii.strashko@ti.com>

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 <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: Rob Herring <robh+dt@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
---
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