uio: Support physical addresses >32 bits on 32-bit systems

To support >32-bit physical addresses for UIO_MEM_PHYS type we need to
extend the width of 'addr' in struct uio_mem.  Numerous platforms like
embedded PPC, ARM, and X86 have support for systems with larger physical
address than logical.

Since 'addr' may contain a physical, logical, or virtual address the
easiest solution is to just change the type to 'phys_addr_t' which
should always be greater than or equal to the sizeof(void *) such that
it can properly hold any of the address types.

For physical address we can support up to a 44-bit physical address on a
typical 32-bit system as we utilize remap_pfn_range() for the mapping of
the memory region and pfn's are represnted by shifting the address by
the page size (typically 4k).

Signed-off-by: Kai Jiang <Kai.Jiang@freescale.com>
Signed-off-by: Minghuan Lian <Minghuan.Lian@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Hans J. Koch <hjk@hansjkoch.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 5 insertions, 2 deletions

diff --git a/include/linux/uio_driver.h b/include/linux/uio_driver.h
index 665517c05eaf..fd99ff9298c6 100644
--- a/include/linux/uio_driver.h
+++ b/include/linux/uio_driver.h
@@ -23,7 +23,10 @@ struct uio_map;
 /**
  * struct uio_mem - description of a UIO memory region
  * @name:               name of the memory region for identification
- * @addr:               address of the device's memory
+ * @addr:               address of the device's memory (phys_addr is used since
+ *                      addr can be logical, virtual, or physical & phys_addr_t
+ *                      should always be large enough to handle any of the
+ *                      address types)
  * @size:               size of IO
  * @memtype:            type of memory addr points to
  * @internal_addr:      ioremap-ped version of addr, for driver internal use
@@ -31,7 +34,7 @@ struct uio_map;
  */
 struct uio_mem {
         const char              *name;
-        unsigned long           addr;
+        phys_addr_t             addr;
         unsigned long           size;
         int                     memtype;
         void __iomem            *internal_addr;