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

[Stefan Roese]

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>

BTW: Please always keep Luka on MVEBU related patches on Cc.

Thanks,
Stefan