2013/5/17 Henrik Nordström henrik@henriknordstrom.net:
fre 2013-05-17 klockan 00:13 +0200 skrev Wolfgang Denk:
There is a common, architecture-independent C API that implements cache flushing/invalidation; please re-read the summary at [1]
Sorry I missed that discussion. Had a bit too much mail for a while.
Or maybe just punt it. If you are on an arch with incoherent caches then make sure to make use of the cache command to flush caches and maybe even disable caches before using go.
The cache commands currently do not support subcommands for flushing / invalidating the caches. See again [1].
From what I see the cache commands do have a sub commands for flushing.
"icache flush" calls icache_invalidate_all().
"dcache flush" calls flush_dcache_all().
but imho the user shouldn't really need to care for these and is why I hooked into the go command.
I don't see much of a performance problem with a automatic full cache flush when using the go command on platforms with incoherent caches. In most use cases it's not very different from the bootm command which also needs to do the same (and using a similar hooking mechanism as what I used for go, but not saying that is a good thing)
Platforms with coherent caches likely do not need to care and can keep the cache as-is.
And I do not think there needs to be commands for flushing specific regions other than for testing. Region based flushing is better done by code which knows what is needed. It's hard for users to get this right as most times it works anyway.
Regards Henrik
U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
How about making the weak aliased arch_preboot_os() global, and then get it invoked in both bootm & go? It looks much pretty to me, and we don't even worry about the i-cache issues.
-- Best wishes, Kuo-Jung Su