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

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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>
This commit is contained in:
Kai Jiang 2011-10-17 20:50:20 +02:00 • committed by Greg Kroah-Hartman
parent c4253cb074
commit 27a90700a4
3 changed files with 9 additions and 7 deletions
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7
include/linux/uio_driver.h
View file

@ -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;