[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, 29 insertions, 20 deletions

diff --git a/arch/arm/mm/ioremap.c b/arch/arm/mm/ioremap.c
index 10901398e4a2..de3ce1eec2ec 100644
--- a/arch/arm/mm/ioremap.c
+++ b/arch/arm/mm/ioremap.c
@@ -86,11 +86,12 @@ remap_area_pmd(pmd_t * pmd, unsigned long address, unsigned long size,
 }
 
 static int
-remap_area_pages(unsigned long start, unsigned long phys_addr,
+remap_area_pages(unsigned long start, unsigned long pfn,
                  unsigned long size, unsigned long flags)
 {
         unsigned long address = start;
         unsigned long end = start + size;
+        unsigned long phys_addr = __pfn_to_phys(pfn);
         int err = 0;
         pgd_t * dir;
 
@@ -130,36 +131,44 @@ remap_area_pages(unsigned long start, unsigned long phys_addr,
  * mapping.  See include/asm-arm/proc-armv/pgtable.h for more information.
  */
 void __iomem *
+__ioremap_pfn(unsigned long pfn, unsigned long offset, size_t size,
+              unsigned long flags)
+{
+        unsigned long addr;
+        struct vm_struct * area;
+
+        area = get_vm_area(size, VM_IOREMAP);
+        if (!area)
+                return NULL;
+        addr = (unsigned long)area->addr;
+        if (remap_area_pages(addr, pfn, size, flags)) {
+                vfree(addr);
+                return NULL;
+        }
+        return (void __iomem *) (offset + (char *)addr);
+}
+EXPORT_SYMBOL(__ioremap_pfn);
+
+void __iomem *
 __ioremap(unsigned long phys_addr, size_t size, unsigned long flags)
 {
-        void * addr;
-        struct vm_struct * area;
-        unsigned long offset, last_addr;
+        unsigned long last_addr;
+        unsigned long offset = phys_addr & ~PAGE_MASK;
+        unsigned long pfn = __phys_to_pfn(phys_addr);
 
-        /* Don't allow wraparound or zero size */
+        /*
+         * Don't allow wraparound or zero size
+         */
         last_addr = phys_addr + size - 1;
         if (!size || last_addr < phys_addr)
                 return NULL;
 
         /*
-         * Mappings have to be page-aligned
+         * Page align the mapping size
          */
-        offset = phys_addr & ~PAGE_MASK;
-        phys_addr &= PAGE_MASK;
         size = PAGE_ALIGN(last_addr + 1) - phys_addr;
 
-        /*
-         * Ok, go for it..
-         */
-        area = get_vm_area(size, VM_IOREMAP);
-        if (!area)
-                return NULL;
-        addr = area->addr;
-        if (remap_area_pages((unsigned long) addr, phys_addr, size, flags)) {
-                vfree(addr);
-                return NULL;
-        }
-        return (void __iomem *) (offset + (char *)addr);
+        return __ioremap_pfn(pfn, offset, size, flags);
 }
 EXPORT_SYMBOL(__ioremap);