[MIPS] FLATMEM: introduce PHYS_OFFSET.

The old code was assuming that min_low_pfn was always 0. This
means that platforms having a big hole at their memory start
paid the price of wasting some memory for the allocation of
unused entries in mem_map[].

This patch prevents this waste.

It introduces PHYS_OFFSET define which is the start of the
physical memory and uses it wherever needed. Specially when
converting physical/virtual addresses into virtual/physical
ones.

Currently all platforms defines PHYS_OFFSET to 0.

Signed-off-by: Franck Bui-Huu <fbuihuu@gmail.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 2 insertions, 2 deletions

diff --git a/include/asm-mips/io.h b/include/asm-mips/io.h
index d77b657c09c7..67f081078904 100644
--- a/include/asm-mips/io.h
+++ b/include/asm-mips/io.h
@@ -115,7 +115,7 @@ static inline void set_io_port_base(unsigned long base)
  */
 static inline unsigned long virt_to_phys(volatile const void *address)
 {
-        return (unsigned long)address - PAGE_OFFSET;
+        return (unsigned long)address - PAGE_OFFSET + PHYS_OFFSET;
 }
 
 /*
@@ -132,7 +132,7 @@ static inline unsigned long virt_to_phys(volatile const void *address)
  */
 static inline void * phys_to_virt(unsigned long address)
 {
-        return (void *)(address + PAGE_OFFSET);
+        return (void *)(address + PAGE_OFFSET - PHYS_OFFSET);
 }
 
 /*