[U-Boot] [PATCH 2/3] ARM: Tegra: USB: Add driver support for Tegra30/Tegra114

[Stephen Warren]

On 05/03/2013 04:53 AM, Jim Lin wrote:
> On Fri, 2013-05-03 at 03:29 +0800, Stephen Warren wrote:
>> On 04/29/2013 03:21 AM, Jim Lin wrote:
>>> Tegra30 and Tegra114 are compatible except
>>> 1. T30 takes 55 ms to finish Port Reset. T114 takes
>>>    50 ms.
>>
>> Is that 55-vs-50 some aspect of the HW specification itself, or the
>> overall result of multiple separate delays? I ask because the statement
>> that one piece of HW differs from another only in a delay, especially
>> where that delay is enormous in HW terms, seem very unusual.
> 
> 50 ms comes from USB 2.0 specification for root port.
> 55 ms comes from T30 Technical Reference Manual.

OK, I see this value is indeed in the TRM, so I guess the code is OK.

> Overall result of multiple separate delays.

That doesn't seem true though; the TRM simply documents a single 55ms
delay, not a set of delays that add up to 55ms.