[U-Boot] USB storage performance EHCI question

Aaron Williams Aaron.Williams at caviumnetworks.com
Sat Jan 15 05:41:06 CET 2011


On 1/14/2011 1:19 AM, Wolfgang Denk wrote:
> Dear Aaron Williams,
>
> please always keep the ML on cc:
>
> In message<4D2FA7F0.7020900 at caviumnetworks.com>  you wrote:
>> It is based off of 2010.09 but I have applied all of the latest USB
>> updates from GIT with the exception of the multiple LUN support (this
>> breaks the SanDisk Cruzer because the Cruzer reports max lun=1). All
>> caches are enabled and this is on a 1.2GHz MIPS which is cache-coherent
>> (no need to flush/invalidate).
> Maybe there are other issues with your code.  It's hard to comment on
> onknown out-of-tree ports.
>
> Best regards,
>
> Wolfgang Denk
>
I don't think so. The only changes I made were to the register access 
macros to use a couple assembly functions since our EHCI registers 
require 64-bit addressing and a very quick virtual to physical 
conversion for the descriptors which is quite fast. Other than that, the 
code is stock from GIT. Note that we do not use interrupts either but 
polling.

Unless I'm reading it wrong it also looks like in EHCI it only uses one 
descriptor and I wonder if this might have something to do with it?

I can provide a diff when I return to the office next week.

-Aaron


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