[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, 4 insertions, 1 deletions

diff --git a/arch/arm/mach-iop13xx/include/mach/memory.h b/arch/arm/mach-iop13xx/include/mach/memory.h
index e012bf13c955..42ae29b288a1 100644
--- a/arch/arm/mach-iop13xx/include/mach/memory.h
+++ b/arch/arm/mach-iop13xx/include/mach/memory.h
@@ -59,7 +59,10 @@ static inline unsigned long __lbus_to_virt(dma_addr_t x)
         })
 
 #define __arch_page_to_dma(dev, page)                                   \
-        __arch_virt_to_dma(dev, page_address(page))
+        ({                                                              \
+                /* __is_lbus_virt() can never be true for RAM pages */  \
+                (dma_addr_t)page_to_phys(page);                         \
+        })
 
 #endif /* CONFIG_ARCH_IOP13XX */
 #endif /* !ASSEMBLY */