Beaglebone USB driver (Mentor Graphics OTG)

[Hans Petter Selasky]

Hi Oleksandr,

Got some time to review the code you committed to HEAD:

1) You need to distinguish between STALL and other errors. This is a bit 
important, because STALL is a PID and other errors can mean anything. 
See attached patch.

2) You should not use the NAKTO feature, because USB devices are allowed 
to NAK forever if they wish to. You should restart a USB transfer 
seamlessly after NAKTO or should use infinite NAKing. The USB stack has 
a timeout on the transfers, and will cancel when timeout happens. By 
feeding these error codes into the USB stack you risk loosing data on 
mouse/keyboard/modem devices! Upon cancel you need to use that trick I 
told you (included in the attached patch), else the double reset of the 
FIFO will crash! Could you clean this up and test a bit. I don't have 
hardware at hand to test at the moment.

Thank you!

--HPS
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