[PATCH u-boot-marvell 03/14] tools: kwboot: Improve retrying logic for incomplete xmodem packets

[Stefan Roese]

On 1/25/22 18:13, Marek Behún wrote:
> From: Pali Rohár <pali at kernel.org>
> 
> Sometimes if the first byte of xmodem packet (SOH) is incorrectly
> transmitted, BootROM sends NAK for every non-SOH received byte, which
> makes BootROM and the host kwboot tool out of sync. BootROM automatically
> re-synchronizes after 2s pause by dropping its input queue. So when
> attempting retransmit for 9th time or later, ignore NAK reply from BootROM
> and either wait for valid ACK or let kwboot timeout, which implies
> re-synchronization.
> 
> This fixes retransmission of xmodem packets and allows kwboot to work also
> without "Waiting ... and flushing tty" code which is at the beginning of
> kwboot xmodem transfer.
> 
> Signed-off-by: Pali Rohár <pali at kernel.org>
> Signed-off-by: Marek Behún <marek.behun at nic.cz>

Reviewed-by: Stefan Roese <sr at denx.de>

Thanks,
Stefan


> ---
>   tools/kwboot.c | 11 ++++++++++-
>   1 file changed, 10 insertions(+), 1 deletion(-)
> 
> diff --git a/tools/kwboot.c b/tools/kwboot.c
> index 1477c0f078..be9a751406 100644
> --- a/tools/kwboot.c
> +++ b/tools/kwboot.c
> @@ -880,6 +880,7 @@ kwboot_baud_magic_handle(int fd, char c, int baudrate)
>   
>   static int
>   kwboot_xm_recv_reply(int fd, char *c, int nak_on_non_xm,
> +		     int ignore_nak_reply,
>   		     int allow_non_xm, int *non_xm_print,
>   		     int baudrate, int *baud_changed)
>   {
> @@ -899,8 +900,14 @@ kwboot_xm_recv_reply(int fd, char *c, int nak_on_non_xm,
>   		}
>   
>   		/* If received xmodem reply, end. */
> -		if (_is_xm_reply(*c))
> +		if (_is_xm_reply(*c)) {
> +			if (*c == NAK && ignore_nak_reply) {
> +				timeout = recv_until - _now();
> +				if (timeout >= 0)
> +					continue;
> +			}
>   			break;
> +		}
>   
>   		/*
>   		 * If receiving/printing non-xmodem text output is allowed and
> @@ -968,6 +975,7 @@ kwboot_xm_sendblock(int fd, struct kwboot_block *block, int allow_non_xm,
>   		}
>   
>   		rc = kwboot_xm_recv_reply(fd, &c, retries < 3,
> +					  retries > 8,
>   					  allow_non_xm, &non_xm_print,
>   					  baudrate, &baud_changed);
>   		if (rc)
> @@ -1011,6 +1019,7 @@ kwboot_xm_finish(int fd)
>   			return rc;
>   
>   		rc = kwboot_xm_recv_reply(fd, &c, retries < 3,
> +					  retries > 8,
>   					  0, NULL, 0, NULL);
>   		if (rc)
>   			return rc;

Viele Grüße,
Stefan Roese

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