[U-Boot] [PATCH] tools/kwboot.c: Support UART fallback mode

[Kevin Smith]

Hi Stefan,

On 03/24/2016 04:29 AM, Stefan Roese wrote:
> Hi Kevin,
>
> On 01.09.2015 14:52, Stefan Roese wrote:
>> Hi Kevin,
>>
>> (Added Luka to Cc, as the Marvell / MVEBU custodian)
>>
>> On 31.08.2015 22:30, Kevin Smith wrote:
>>> On some processors such as Armada 38x, if the hardware-
>>> configured boot mode fails, the CPU falls back to booting over
>>> UART.  When this happens the chip prints a failure message, waits
>>> for the magic sequence and, when it is received, prints a
>>> "(boot)" message, then sends a NAK to start the transfer.
>>>
>>> This breaks the current kwboot behavior because the xmodem
>>> transfer only tries to read one character after the magic
>>> sequence, looking for the NAK.  Instead it gets the "(boot)"
>>> text, and retries the magic sequence.  The CPU thinks the
>>> repeated sequence is part of the packet, stops NAKing, and one
>>> side or another eventually times out.
>>>
>>> This patch adds support for a fallback mode which continues to
>>> scan for a NAK in the characters received after the sequence,
>>> printing out any non-NAK characters.  This allows kwboot to skip
>>> the "(boot)" message, find the NAK, and start the transfer
>>> successfully.
>>>
>>> Signed-off-by: Kevin Smith <kevin.smith at elecsyscorp.com>
>>
>> I've not seen this "(boot)" yet. But the patch looks good. So:
>>
>> Reviewed-by: Stefan Roese <sr at denx.de>
>
> Is this patch still needed (or helpful)? If yes, please rebase
> on top of latest u-boot-marvell/master and send a new version
> so that I can pick it up.
>
> Thanks,
> Stefan
>
I don't think this is needed in most cases.  I will leave it out to 
avoid cluttering up the program.  If that changes, I will resubmit.

Thank you,
Kevin