Yes I thought it might be a problem with the TLB. Where does the TLB initialization take place in the Linux kernel? I am able to access any other peripherals on the chip as there TLB entries appear to be properly allocated. I am remapping the physical address for all peripherals that I am working with. I have attached the driver code for reference.
Dave -----Original Message----- From: Josh Boyer [mailto:[EMAIL PROTECTED] Sent: Monday, September 24, 2007 4:42 PM To: Dave Cogley Cc: linuxppc-embedded@ozlabs.org Subject: Re: EBC peripheral, access causing Machine Check On Mon, 24 Sep 2007 12:19:01 -0700 "Dave Cogley" <[EMAIL PROTECTED]> wrote: > Good Afternoon, > > > > I am using an AMCC 440EPx processor with an FPGA peripheral attached to the > EBC. I am doing the entire bank configuration in the u-boot boot loader > before Linux is loaded. I can directly read and write registers using > memory read and write (md, nm) within area 0xC0000000 to 0xC000FFFF direct > memory I/O within the context of u-boot without any faults. When I attempt > to access any register in area 0xC000000 within the context of my Linux > device driver I get a Machine Check fault (attached text) which appears to > be an access permission violation. I am currently running the DENX ELDK > 2.6.19.2 platform that was specific to the "Sequoia" platform. > > > > I have configured the EBC access permissions and control resisters as > follows for bank 1: > > > > PB1CR: 0xC003C000 > > PB1AP: 0x80040380 You need proper TLB entries set up before you can access things. Linux discards the MMU settings that U-Boot does. So your driver needs to call ioremap on the physical address. Other than that, we can't help you much without your driver code. josh
banjodecoder.tar.gz
Description: GNU Zip compressed data
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