[PATCH 2/2] Set of fixes for DMA when dma_addr_t != physical address

[David VomLehn <dvomlehn@cisco.com>]

Fixes for using DMA on systems where the DMA address and the physical address
differ.

Signed-off-by: Dezhong Diao <dediao@cisco.com>
Signed-off-by: David VomLehn <dvomlehn@cisco.com>
---
 arch/mips/mm/dma-default.c |   22 ++++++++++++++--------
 1 files changed, 14 insertions(+), 8 deletions(-)

diff --git a/arch/mips/mm/dma-default.c b/arch/mips/mm/dma-default.c
index 414d7ff..eaa7fb4 100644
--- a/arch/mips/mm/dma-default.c
+++ b/arch/mips/mm/dma-default.c
@@ -24,8 +24,11 @@ static inline unsigned long dma_addr_to_virt(struct device 
*dev,
        dma_addr_t dma_addr)
 {
        unsigned long addr = plat_dma_addr_to_phys(dev, dma_addr);
+       unsigned int offset = (dma_addr & ~PAGE_MASK);
+       struct page *pg;
 
-       return (unsigned long)phys_to_virt(addr);
+       pg = pfn_to_page(addr >> PAGE_SHIFT);
+       return (unsigned long)(page_address(pg) + offset);
 }
 
 /*
@@ -136,7 +139,6 @@ EXPORT_SYMBOL(dma_free_coherent);
 static inline void __dma_sync(unsigned long addr, size_t size,
        enum dma_data_direction direction)
 {
-
        BUG_ON(addr < KSEG0);
 
        switch (direction) {
@@ -197,8 +199,8 @@ int dma_map_sg(struct device *dev, struct scatterlist *sg, 
int nents,
                addr = (unsigned long) sg_virt(sg);
                if (!plat_device_is_coherent(dev) && (addr >= KSEG0))
                        __dma_sync(addr, sg->length, direction);
-
-               sg->dma_address = sg_phys(sg);
+               sg->dma_address = plat_map_dma_mem_page(dev, sg_page(sg)) +
+                       sg->offset;
        }
 
        return nents;
@@ -253,7 +255,8 @@ void dma_sync_single_for_cpu(struct device *dev, dma_addr_t 
dma_handle,
                unsigned long addr;
 
                addr = dma_addr_to_virt(dev, dma_handle);
-               __dma_sync(addr, size, direction);
+               if (addr >= KSEG0)
+                       __dma_sync(addr, size, direction);
        }
 }
 
@@ -269,7 +272,8 @@ void dma_sync_single_for_device(struct device *dev, 
dma_addr_t dma_handle,
                unsigned long addr;
 
                addr = dma_addr_to_virt(dev, dma_handle);
-               __dma_sync(addr, size, direction);
+               if (addr >= KSEG0)
+                       __dma_sync(addr, size, direction);
        }
 }
 
@@ -284,7 +288,8 @@ void dma_sync_single_range_for_cpu(struct device *dev, 
dma_addr_t dma_handle,
                unsigned long addr;
 
                addr = dma_addr_to_virt(dev, dma_handle);
-               __dma_sync(addr + offset, size, direction);
+               if (addr >= KSEG0)
+                       __dma_sync(addr + offset, size, direction);
        }
 }
 
@@ -300,7 +305,8 @@ void dma_sync_single_range_for_device(struct device *dev, 
dma_addr_t dma_handle,
                unsigned long addr;
 
                addr = dma_addr_to_virt(dev, dma_handle);
-               __dma_sync(addr + offset, size, direction);
+               if (addr >= KSEG0)
+                       __dma_sync(addr + offset, size, direction);
        }
 }