[ARM] 3070/2: Add __ioremap_pfn() API

Patch from Deepak Saxena

In working on adding 36-bit addressed supersection support to ioremap(),
I came to the conclusion that it would be far simpler to do so by just
splitting __ioremap() into a main external interface and adding an
__ioremap_pfn() function that takes a pfn + offset into the page that
__ioremap() can call. This way existing callers of __ioremap() won't have
to change their code and 36-bit systems will just call __ioremap_pfn()
and we will not have to deal with unsigned long long variables.

Note that __ioremap_pfn() should _NOT_ be called directly by drivers
but is reserved for use by arch_ioremap() implementations that map
32-bit resource regions into the real 36-bit address and then call
this new function.

Signed-off-by: Deepak Saxena <dsaxena@plexity.net>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 6 insertions, 0 deletions

diff --git a/include/asm-arm/io.h b/include/asm-arm/io.h
index 0cf4d4f99600..fd0147e52dbb 100644
--- a/include/asm-arm/io.h
+++ b/include/asm-arm/io.h
@@ -56,7 +56,12 @@ extern void __raw_readsl(const void __iomem *addr, void *data, int longlen);
 
 /*
  * Architecture ioremap implementation.
+ *
+ * __ioremap takes CPU physical address.
+ *
+ * __ioremap_pfn takes a Page Frame Number and an offset into that page
  */
+extern void __iomem * __ioremap_pfn(unsigned long, unsigned long, size_t, unsigned long);
 extern void __iomem * __ioremap(unsigned long, size_t, unsigned long);
 extern void __iounmap(void __iomem *addr);
 
@@ -261,6 +266,7 @@ out:
  *
  * ioremap takes a PCI memory address, as specified in
  * Documentation/IO-mapping.txt.
+ *
  */
 #ifndef __arch_ioremap
 #define ioremap(cookie,size)            __ioremap(cookie,size,0)