Hi, checkout arch/ppc/mm/pgtable.c there you'll find the ioremap function which is used to remap physical addresses. This function calls internaly fixup_big_physaddr(), defined in arch/ppc/kernel/ibm44x_common.c 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, Gerhard 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 ** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/
