Hi Nicolas, On Wednesday 11 July 2007 17:39, Nicolas Mederle wrote: > Hi, > > I am porting linux on a custom board equipped with a PPC750, and I > will like to have some advices on the MMU. I used the powerpc arch, and > I built my device tree. > I will like to know in which files we can configure the > authorizations access for the I/O registers. When I use the function > md_ppc.progress, I have a data access fault. I modified the head. S > files, for add the BAT config. But I think that it is not correct, and > that it is possible to do it elsewhere (platform_init?). Moreover the > kernel modify the MMU config, it removes the BATs, and configures the > Registers Segments. So, must I remake the configuration? Or is it > possible to indicate, at the beginning, which space is reserved for I/O? > I studied several patch (sandpoint, PrPMC2800) but none configures > really the MMU for I/O registers. In the same way, I read several books, > but I am not able to have information that I seek, therefore I am really > blocked. I warmly thank you for the assistance which you will be able to > bring to me. > > Mapping : 0x0000 0000 -> 0x0FFF FFFF : RAM > 0x2000 0000 -> 0x201F FFFF : ASIC ( > UART, DMA, GPIO, PIC...) > 0x8000 0000 -> 0x8FFF FFFF : PCI > 0xF000 0000 -> 0xFFFF FFFF : Flash > The kernel is load at 0x0, an the system is a Run In Memory. > Currently, I don't use the flash.
You should ioremap() the memory you want to access, and use the I/O access functions defined in asm/io.h. Don't forget to iounmap() once you're done. Best regards, Laurent Pinchart _______________________________________________ Linuxppc-embedded mailing list [email protected] https://ozlabs.org/mailman/listinfo/linuxppc-embedded
