440GX: mapping PCI address

Gerhard Jaeger g.jaeger at sysgo.com
Thu Jul 22 21:47:50 EST 2004


there you'll find the ioremap function which is used to remap physical
addresses. This function calls internaly fixup_big_physaddr(), defined in
This fixup_big_physaddr() adjusts some 32bit addresses to some corresponding
36bit addresses, which can be mapped by the kernel by calling ioremap64.
Your example:
Calling mmap with the address 0x80002000 (see also include/asm-ppc/ibm44x.h)
will map the PCI area, by trapping this 0x80002000 and making a 36bit address
out of it. There a 3 "trap" areas defined:
 * 36-bit trap ranges
#define PPC44x_IO_LO            0x40000000
#define PPC44x_IO_HI            0x40001000
#define PPC44x_PCICFG_LO        0x0ec00000
#define PPC44x_PCICFG_HI        0x0ec7ffff
#define PPC44x_PCIMEM_LO        0x80002000
#define PPC44x_PCIMEM_HI        0xffffffff

Hope this helps,

On Thursday 22 July 2004 11:58, Barbier, Renaud (GE Infrastructure) wrote:
> As you know the PCI address(and other embedded device) are seen through a
> 36-bit address space.
> How do you map this address from user space?
> I have seen a message from 2002 saying it is not supported. Anything new
> since then?
> thanks.

Gerhard Jaeger                             g.jaeger at sysgo.com
SYSGO AG                      Embedded and Real-Time Software
Voice: + 49 731 94683-0                Fax: + 49 731 94683-10
www.sysgo.com | www.elinos.com | www.osek.de | www.imerva.com

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