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

On 1/25/22 18:13, Marek Behún wrote:

From: Pali Rohár pali@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@kernel.org Signed-off-by: Marek Behún marek.behun@nic.cz

Reviewed-by: Stefan Roese sr@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