Hi, I am new to Linux embedded programming. I have experience programming microcontrollers and DSPs without an operating system, so I have some idea what I'm doing. Anyhow, I'm trying to use the peripheral memory bus on my 405EP CerfCube from Intrinsyc. Does anyone have an example that I can work from?
To setup the memory's timings, I need access to the DCR register. In the PowerPC datasheet it says to use assembly instructions mtdcr and mfdcr. I don't know much about assembly, but I found a kernel patch that uses these functions. So, working off this patch, I tried making a simple program to read these registers. When I run it, Linux reports an "Illegal instruction" and doesn't let me access the register. Does access to this bus need to be done in "kernel mode"? If so, where can I find more information about writing a kernel driver? Ideally, I'd like to just open a device file and read/write to the bus. Thanks! -Paul ** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/
