In message 200708081147.09111.rgetz@blackfin.uclinux.org you wrote:
I think it is reasonable/prudent to turn off cache in all situations, on all architectures.
No, it is not. Some architectures / operating systems may require cache(s) being on. Some others may not care, except for boot speed which in turn is something some of the customers do care about.
Finally, I don't want to fix a prblem where non exists.
If we know for sure that certain systems require caches disabeled, then let's provide them this environment; but please leave all the rest unchanged.
Instruction and data caches in U-Boot are a great thing, since it decreases the time for a kernel or file system to be loaded, decompressed, but once U-Boot looses control (the jump to the unknown application), it shouldn't expect a return, or the hardware not to be changed by the app.
There is more than just Linux...
go, bootm, boote, etc - should flush & turn off cache before the jump to the application code (should also turn off what limited interrupts are enabled) to be safe.
I disagree.
Best regards,
Wolfgang Denk