[ARM] make page_to_dma() highmem aware

If a machine class has a custom __virt_to_bus() implementation then it
must provide a __arch_page_to_dma() implementation as well which is
_not_ based on page_address() to support highmem.

This patch fixes existing __arch_page_to_dma() and provide a default
implementation otherwise.  The default implementation for highmem is
based on __pfn_to_bus() which is defined only when no custom
__virt_to_bus() is provided by the machine class.

That leaves only ebsa110 and footbridge which cannot support highmem
until they provide their own __arch_page_to_dma() implementation.
But highmem support on those legacy platforms with limited memory is
certainly not a priority.

Signed-off-by: Nicolas Pitre <nico@marvell.com>

1 files changed, 5 insertions, 1 deletions

diff --git a/arch/arm/mach-ks8695/include/mach/memory.h b/arch/arm/mach-ks8695/include/mach/memory.h
index 6d5887cf5742..76e5308685a4 100644
--- a/arch/arm/mach-ks8695/include/mach/memory.h
+++ b/arch/arm/mach-ks8695/include/mach/memory.h
@@ -35,7 +35,11 @@ extern struct bus_type platform_bus_type;
                                         __phys_to_virt(x) : __bus_to_virt(x)); })
 #define __arch_virt_to_dma(dev, x)      ({ is_lbus_device(dev) ? \
                                         (dma_addr_t)__virt_to_phys(x) : (dma_addr_t)__virt_to_bus(x); })
-#define __arch_page_to_dma(dev, x)      __arch_virt_to_dma(dev, page_address(x))
+#define __arch_page_to_dma(dev, x)      \
+        ({ dma_addr_t __dma = page_to_phys(page); \
+           if (!is_lbus_device(dev)) \
+                __dma = __dma - PHYS_OFFSET + KS8695_PCIMEM_PA; \
+           __dma; })
 
 #endif