Inline ioremap() calls for constant addresses that map to KSEG1.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 29 insertions, 2 deletions

diff --git a/include/asm-mips/io.h b/include/asm-mips/io.h
index 3b4d97d80643..42f80782acd2 100644
--- a/include/asm-mips/io.h
+++ b/include/asm-mips/io.h
@@ -27,6 +27,7 @@
 #include <asm/processor.h>
 #include <asm/string.h>
 
+#include <ioremap.h>
 #include <mangle-port.h>
 
 /*
@@ -209,6 +210,8 @@ extern void __iounmap(volatile void __iomem *addr);
 static inline void __iomem * __ioremap_mode(phys_t offset, unsigned long size,
         unsigned long flags)
 {
+#define __IS_LOW512(addr) (!((phys_t)(addr) & (phys_t) ~0x1fffffffULL))
+
         if (cpu_has_64bit_addresses) {
                 u64 base = UNCAC_BASE;
 
@@ -219,9 +222,29 @@ static inline void __iomem * __ioremap_mode(phys_t offset, unsigned long size,
                 if (flags == _CACHE_UNCACHED)
                         base = (u64) IO_BASE;
                 return (void __iomem *) (unsigned long) (base + offset);
+        } else if (__builtin_constant_p(offset) &&
+                   __builtin_constant_p(size) && __builtin_constant_p(flags)) {
+                phys_t phys_addr, last_addr;
+
+                phys_addr = fixup_bigphys_addr(offset, size);
+
+                /* Don't allow wraparound or zero size. */
+                last_addr = phys_addr + size - 1;
+                if (!size || last_addr < phys_addr)
+                        return NULL;
+
+                /*
+                 * Map uncached objects in the low 512MB of address
+                 * space using KSEG1.
+                 */
+                if (__IS_LOW512(phys_addr) && __IS_LOW512(last_addr) &&
+                    flags == _CACHE_UNCACHED)
+                        return (void __iomem *)CKSEG1ADDR(phys_addr);
         }
 
         return __ioremap(offset, size, flags);
+
+#undef __IS_LOW512
 }
 
 /*
@@ -273,12 +296,16 @@ static inline void __iomem * __ioremap_mode(phys_t offset, unsigned long size,
 
 static inline void iounmap(volatile void __iomem *addr)
 {
-        if (cpu_has_64bit_addresses)
+#define __IS_KSEG1(addr) (((unsigned long)(addr) & ~0x1fffffffUL) == CKSEG1)
+
+        if (cpu_has_64bit_addresses ||
+            (__builtin_constant_p(addr) && __IS_KSEG1(addr)))
                 return;
 
         __iounmap(addr);
-}
 
+#undef __IS_KSEG1
+}
 
 #define __BUILD_MEMORY_SINGLE(pfx, bwlq, type, irq)                     \
                                                                         \