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>
diff --git a/Documentation/DocBook/uio-howto.tmpl b/Documentation/DocBook/uio-howto.tmpl
index 7c4b514d..54883de 100644
--- a/Documentation/DocBook/uio-howto.tmpl
+++ b/Documentation/DocBook/uio-howto.tmpl
@@ -529,7 +529,7 @@
</para></listitem>
<listitem><para>
-<varname>unsigned long addr</varname>: Required if the mapping is used.
+<varname>phys_addr_t addr</varname>: Required if the mapping is used.
Fill in the address of your memory block. This address is the one that
appears in sysfs.
</para></listitem>