|To:||unlisted-recipients:; (no To-header on input)|
|Subject:||Re: Porting Au1x000 USB host controller on u-boot|
|From:||Sergei Shtylyov <firstname.lastname@example.org>|
|Date:||Thu, 04 May 2006 21:16:19 +0400|
|Cc:||Rodolfo Giometti <email@example.com>, Linux-MIPS <firstname.lastname@example.org>|
|Organization:||MontaVista Software Inc.|
|User-agent:||Mozilla/5.0 (X11; U; Linux i686; rv:1.7.2) Gecko/20040803|
Hello, I wrote:
I'm trying to implement support for USB host into u-boot. I initialized the USB controller just as linux does, the EDs and the TDs look like good in memory but the controller seems not well reading them and on the bus I see random USB messages...
I think that there could be some problem on memory coherency... some suggestion?
try to disable USB controller's DMA coherency in the USB enable register (there's a related errata in all Au1xx0 family) -- the Linux driver doesn't do this though, and this shouldn't matter unless you're modifying USB buffers on the fly. :-)
AND make sure every buffer/TD/ED is written back / invalidated from cache before the OHCI accesses them since the cache coherency on Au1xx0 is b0rken!
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