Hello, I am working with the xilinx ML403 evaluation board which has a Virtex4 FPGA and one powerpc405 processor is integrated.
I am trying to develop a linux driver for FSL link for powerpc405. I developed one first version (with the referce of the microblaze fsl driver developped by Mr. John Williams for uClinux) as a loadable module, and loaded it after Linux is booted. But when I run some testing function like "cat /dev/fslfifo", it crashes the kernel. I suppose that it is because FSL operations (like nget, nput, etc. ) are not part of the ppc instruction set and are realized by APU instruction extension. For the processor to execute the extended instructions correctly, the MSR register should be set accordingly to enable APU. (XREG_MSR_APU_AVAILABLE + XREG_MSR_APU_ENABLE). Before I worked with ppc without os, and the management of special purpose registers are rather straight forward and it concerns only some assembly language at the beginning of the main() function. But with os, I have no experience dealing explicitely with special purpose registers. So I tried the following: I set the MSR at the initialisation phase by mtmsr(XREG_MSR_APU_AVAILABLE | XREG_MSR_APU_ENABLE | mfmsr()) However, when I set the MSR at the initialization function, and test afterwards, the MSR value is set back to some default value. I don't know where it happened neighter do I know if I am using the correct measure to change the MSR value. Does anybody have any suggestions? Thank you, Guangye _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev
