Re: [PATCH resend 5/9] MIPS: sync after cacheflush

Gleb O. Raiko
2010-10-19T09:34:26Z

On 18.10.2010 23:41, Kevin Cernekee wrote:
> I have not been able to find any official statement from MIPS that
> says that CACHE + SYNC should be used, but that seems like the most
> intuitive way to implement things on the hardware side.

Indeed, both Architecture for Programmers in Vol. 2 describing
instruction sets not so clearly say that sync is needed after cache.
For example, documents with rev. 2.62, p. 92 (for MIPS32 ISA) or p. 96
(for MIPS64).

Considering whether just sync enough I'd like to note some boxes may
implement dma master and slave blocks to be unsynchronized. Also,there
may be write buffers somewhere in the path between cpu, memory, and even
a dma master.

BTW, we have plat_extra_sync_for_device which has appropriate name but
invented to do things before cache flush. :-) It seems we need another
one which will do something after.

Gleb.