Hi all,

We've discovered something interesting when not using a bootloader such as 
uboot to start Linux.

The Linux kernel seems to be depending on the bootloader to set up the ppc440 
cache control registers, ivlim and dvlim, to set up the Normal and Transient 
areas in the caches. When a separate bootloader is not used, these cache 
control registers have random values.

I can think of a couple reasons why somone might not want to use a separate 
bootloader. Their device could be so small that there's not enough flash to 
store booth the bootloader, the kernel image, and other things they need in 
flash. They could want to improve bootup time for their device.

I was thinking it might be good to have the kernel initialize these cache 
control registers in it's own start up code. Or perhaps this could be done in 
the kernel's simple bootloader. We could probably put this change in a Xilinx 
specific startup file, but this change doesn't seem specific to Xilinx FPGA 
boards.

Thoughts?

- John

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