From: Grygorii Strashko <grygorii.strashko@xxxxxx>
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
This patch introduces new field dma_pfn_offset in ARM dev_archdata
structure which has to be filed per-device at arch init time
(simplest way is to use Platform bus notifier to handle
BUS_NOTIFY_ADD_DEVICE event) and updates DMA address translation
routines in order to accommodate bus offset value by default.
Cc: Russell King <linux@xxxxxxxxxxxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Olof Johansson <olof@xxxxxxxxx>
Signed-off-by: Grygorii Strashko <grygorii.strashko@xxxxxx>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@xxxxxx>
---
arch/arm/include/asm/device.h | 1 +
arch/arm/include/asm/dma-mapping.h | 17 +++++++++++++----
2 files changed, 14 insertions(+), 4 deletions(-)
diff --git a/arch/arm/include/asm/device.h b/arch/arm/include/asm/device.h
index dc662fc..861961c 100644
--- a/arch/arm/include/asm/device.h
+++ b/arch/arm/include/asm/device.h
@@ -8,6 +8,7 @@
struct dev_archdata {
struct dma_map_ops *dma_ops;
+ unsigned long dma_pfn_offset;
#ifdef CONFIG_DMABOUNCE
struct dmabounce_device_info *dmabounce;
#endif
diff --git a/arch/arm/include/asm/dma-mapping.h b/arch/arm/include/asm/dma-mapping.h
index e701a4d..247ed72 100644
--- a/arch/arm/include/asm/dma-mapping.h
+++ b/arch/arm/include/asm/dma-mapping.h
@@ -58,22 +58,31 @@ 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_ERROR_CODE;
+ return (dma_addr_t)__pfn_to_bus(pfn - dev->archdata.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 0;
+ return __bus_to_pfn(addr) + dev->archdata.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 NULL;
+ 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_ERROR_CODE;
+ return pfn_to_dma(dev,
+ __bus_to_pfn(__virt_to_bus((unsigned long)(addr))));
}
#else
--
1.7.9.5
--
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