MPC860 reorder and invalidate dcache

Joakim Tjernlund joakim.tjernlund at
Sat Aug 17 01:50:42 EST 2002


I wonder if the MPC860 really can reorder I/O memory accesses?

I am using JFFS2 FS on Intel Strata flash. I remap the flash with
ioremap_nocache(flash_start, flash_size) and use the resulting address
to access the flash. Whenever a write is performed to the flash I do a
wmb() to enforce ordered writes and that affects performance somewhat.
Is the wmb() required or can I skip it?

Invalidate Data Cache
I have noticed that invalidate_dcache_range() performs a 'sync' just before it returns. Why?
Is it not enough to execute 'dcbi' on the affected address space?

Is there a faster way to invalidate the dcache for a big(256KB) area than using invalidate_dcache_range().
The area is PAGE aligned.


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