From 27a90700a4275c5178b883b65927affdafa5185c Mon Sep 17 00:00:00 2001 From: Kai Jiang Date: Mon, 17 Oct 2011 20:50:20 +0200 Subject: 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 Signed-off-by: Minghuan Lian Signed-off-by: Kumar Gala Signed-off-by: Hans J. Koch Signed-off-by: Greg Kroah-Hartman --- Documentation/DocBook/uio-howto.tmpl | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'Documentation/DocBook') diff --git a/Documentation/DocBook/uio-howto.tmpl b/Documentation/DocBook/uio-howto.tmpl index 7c4b514d62b1..54883de5d5f9 100644 --- a/Documentation/DocBook/uio-howto.tmpl +++ b/Documentation/DocBook/uio-howto.tmpl @@ -529,7 +529,7 @@ memory (e.g. allocated with kmalloc()). There's also -unsigned long addr: Required if the mapping is used. +phys_addr_t addr: Required if the mapping is used. Fill in the address of your memory block. This address is the one that appears in sysfs. -- cgit v1.2.3