Introduce map_physmem() and unmap_physmem()

map_physmem() returns a virtual address which can be used to access a
given physical address without involving the cache. unmap_physmem()
should be called when the virtual address returned by map_physmem() is
no longer needed.

This patch adds a stub implementation which simply returns the
physical address cast to a uchar * for all architectures except AVR32,
which converts the physical address to an uncached virtual mapping.
unmap_physmem() is a no-op on all architectures, but if any
architecture needs to do such mappings through the TLB, this is the
hook where those TLB entries can be invalidated.

Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>

include/asm-arm/io.h

@@ -33,6 +33,32 @@ static inline void sync(void)
 {
 }
 
+/*
+ * Given a physical address and a length, return a virtual address
+ * that can be used to access the memory range with the caching
+ * properties specified by "flags".
+ */
+typedef unsigned long phys_addr_t;
+
+#define MAP_NOCACHE	(0)
+#define MAP_WRCOMBINE	(0)
+#define MAP_WRBACK	(0)
+#define MAP_WRTHROUGH	(0)
+
+static inline void *
+map_physmem(phys_addr_t paddr, unsigned long len, unsigned long flags)
+{
+	return (void *)paddr;
+}
+
+/*
+ * Take down a mapping set up by map_physmem().
+ */
+static inline void unmap_physmem(void *vaddr, unsigned long flags)
+{
+
+}
+
 /*
  * Generic virtual read/write.  Note that we don't support half-word
  * read/writes.  We define __arch_*[bl] here, and leave __arch_*w

include/asm-avr32/io.h

@@ -93,4 +93,36 @@ static inline void sync(void)
 {
 }
 
+/*
+ * Given a physical address and a length, return a virtual address
+ * that can be used to access the memory range with the caching
+ * properties specified by "flags".
+ *
+ * This implementation works for memory below 512MiB (flash, etc.) as
+ * well as above 3.5GiB (internal peripherals.)
+ */
+typedef unsigned long phys_addr_t;
+
+#define MAP_NOCACHE	(0)
+#define MAP_WRCOMBINE	(1 << 7)
+#define MAP_WRBACK	(MAP_WRCOMBINE | (1 << 9))
+#define MAP_WRTHROUGH	(MAP_WRBACK | (1 << 0))
+
+static inline void *
+map_physmem(phys_addr_t paddr, unsigned long len, unsigned long flags)
+{
+	if (flags == MAP_WRBACK)
+		return (void *)P1SEGADDR(paddr);
+	else
+		return (void *)P2SEGADDR(paddr);
+}
+
+/*
+ * Take down a mapping set up by map_physmem().
+ */
+static inline void unmap_physmem(void *vaddr, unsigned long len)
+{
+
+}
+
 #endif /* __ASM_AVR32_IO_H */

include/asm-blackfin/io.h

@@ -40,6 +40,32 @@ static inline void sync(void)
 	__builtin_bfin_ssync();
 }
 
+/*
+ * Given a physical address and a length, return a virtual address
+ * that can be used to access the memory range with the caching
+ * properties specified by "flags".
+ */
+typedef unsigned long phys_addr_t;
+
+#define MAP_NOCACHE	(0)
+#define MAP_WRCOMBINE	(0)
+#define MAP_WRBACK	(0)
+#define MAP_WRTHROUGH	(0)
+
+static inline void *
+map_physmem(phys_addr_t paddr, unsigned long len, unsigned long flags)
+{
+	return (void *)paddr;
+}
+
+/*
+ * Take down a mapping set up by map_physmem().
+ */
+static inline void unmap_physmem(void *vaddr, unsigned long flags)
+{
+
+}
+
 /*
  * These are for ISA/PCI shared memory _only_ and should never be used
  * on any other type of memory, including Zorro memory. They are meant to

include/asm-i386/io.h

@@ -205,4 +205,30 @@ static inline void sync(void)
 {
 }
 
+/*
+ * Given a physical address and a length, return a virtual address
+ * that can be used to access the memory range with the caching
+ * properties specified by "flags".
+ */
+typedef unsigned long phys_addr_t;
+
+#define MAP_NOCACHE	(0)
+#define MAP_WRCOMBINE	(0)
+#define MAP_WRBACK	(0)
+#define MAP_WRTHROUGH	(0)
+
+static inline void *
+map_physmem(phys_addr_t paddr, unsigned long len, unsigned long flags)
+{
+	return (void *)paddr;
+}
+
+/*
+ * Take down a mapping set up by map_physmem().
+ */
+static inline void unmap_physmem(void *vaddr, unsigned long flags)
+{
+
+}
+
 #endif

include/asm-m68k/io.h

@@ -232,4 +232,31 @@ static inline void sync(void)
 	 * compatibility (CFI driver)
 	 */
 }
+
+/*
+ * Given a physical address and a length, return a virtual address
+ * that can be used to access the memory range with the caching
+ * properties specified by "flags".
+ */
+typedef unsigned long phys_addr_t;
+
+#define MAP_NOCACHE	(0)
+#define MAP_WRCOMBINE	(0)
+#define MAP_WRBACK	(0)
+#define MAP_WRTHROUGH	(0)
+
+static inline void *
+map_physmem(phys_addr_t paddr, unsigned long len, unsigned long flags)
+{
+	return (void *)paddr;
+}
+
+/*
+ * Take down a mapping set up by map_physmem().
+ */
+static inline void unmap_physmem(void *vaddr, unsigned long flags)
+{
+
+}
+
 #endif				/* __ASM_M68K_IO_H__ */

include/asm-microblaze/io.h

@@ -129,4 +129,30 @@ static inline void sync(void)
 {
 }
 
+/*
+ * Given a physical address and a length, return a virtual address
+ * that can be used to access the memory range with the caching
+ * properties specified by "flags".
+ */
+typedef unsigned long phys_addr_t;
+
+#define MAP_NOCACHE	(0)
+#define MAP_WRCOMBINE	(0)
+#define MAP_WRBACK	(0)
+#define MAP_WRTHROUGH	(0)
+
+static inline void *
+map_physmem(phys_addr_t paddr, unsigned long len, unsigned long flags)
+{
+	return (void *)paddr;
+}
+
+/*
+ * Take down a mapping set up by map_physmem().
+ */
+static inline void unmap_physmem(void *vaddr, unsigned long flags)
+{
+
+}
+
 #endif /* __MICROBLAZE_IO_H__ */

include/asm-mips/io.h

@@ -465,4 +465,30 @@ static inline void sync(void)
 {
 }
 
+/*
+ * Given a physical address and a length, return a virtual address
+ * that can be used to access the memory range with the caching
+ * properties specified by "flags".
+ */
+typedef unsigned long phys_addr_t;
+
+#define MAP_NOCACHE	(0)
+#define MAP_WRCOMBINE	(0)
+#define MAP_WRBACK	(0)
+#define MAP_WRTHROUGH	(0)
+
+static inline void *
+map_physmem(phys_addr_t paddr, unsigned long len, unsigned long flags)
+{
+	return (void *)paddr;
+}
+
+/*
+ * Take down a mapping set up by map_physmem().
+ */
+static inline void unmap_physmem(void *vaddr, unsigned long flags)
+{
+
+}
+
 #endif /* _ASM_IO_H */

include/asm-nios/io.h

@@ -109,4 +109,30 @@ static inline void sync(void)
 {
 }
 
+/*
+ * Given a physical address and a length, return a virtual address
+ * that can be used to access the memory range with the caching
+ * properties specified by "flags".
+ */
+typedef unsigned long phys_addr_t;
+
+#define MAP_NOCACHE	(0)
+#define MAP_WRCOMBINE	(0)
+#define MAP_WRBACK	(0)
+#define MAP_WRTHROUGH	(0)
+
+static inline void *
+map_physmem(phys_addr_t paddr, unsigned long len, unsigned long flags)
+{
+	return (void *)paddr;
+}
+
+/*
+ * Take down a mapping set up by map_physmem().
+ */
+static inline void unmap_physmem(void *vaddr, unsigned long flags)
+{
+
+}
+
 #endif /* __ASM_NIOS_IO_H_ */

include/asm-nios2/io.h

@@ -29,6 +29,32 @@ static inline void sync(void)
 	__asm__ __volatile__ ("sync" : : : "memory");
 }
 
+/*
+ * Given a physical address and a length, return a virtual address
+ * that can be used to access the memory range with the caching
+ * properties specified by "flags".
+ */
+typedef unsigned long phys_addr_t;
+
+#define MAP_NOCACHE	(0)
+#define MAP_WRCOMBINE	(0)
+#define MAP_WRBACK	(0)
+#define MAP_WRTHROUGH	(0)
+
+static inline void *
+map_physmem(phys_addr_t paddr, unsigned long len, unsigned long flags)
+{
+	return (void *)paddr;
+}
+
+/*
+ * Take down a mapping set up by map_physmem().
+ */
+static inline void unmap_physmem(void *vaddr, unsigned long flags)
+{
+
+}
+
 extern unsigned char inb (unsigned char *port);
 extern unsigned short inw (unsigned short *port);
 extern unsigned inl (unsigned port);

include/asm-ppc/io.h

@@ -238,4 +238,30 @@ extern inline void out_be32(volatile unsigned __iomem *addr, int val)
 	__asm__ __volatile__("sync; stw%U0%X0 %1,%0" : "=m" (*addr) : "r" (val));
 }
 
+/*
+ * Given a physical address and a length, return a virtual address
+ * that can be used to access the memory range with the caching
+ * properties specified by "flags".
+ */
+typedef unsigned long phys_addr_t;
+
+#define MAP_NOCACHE	(0)
+#define MAP_WRCOMBINE	(0)
+#define MAP_WRBACK	(0)
+#define MAP_WRTHROUGH	(0)
+
+static inline void *
+map_physmem(phys_addr_t paddr, unsigned long len, unsigned long flags)
+{
+	return (void *)paddr;
+}
+
+/*
+ * Take down a mapping set up by map_physmem().
+ */
+static inline void unmap_physmem(void *vaddr, unsigned long flags)
+{
+
+}
+
 #endif