[U-Boot] [PATCH] tools: kwboot: Make kwboot more robust on a38x

[Baruch Siach]

From: Jon Nettleton <jon at solid-run.com>

This patch accomplishes 2 things to make the kwboot procedure
on the a38x more reliable.

1)  We fill the tty with 1K of the magic bootparam.  This helps
with the timing of where the microcode picks up in the read of
the line to ensure we actually catch the break to go into recovery
mode

2)  Before starting the xmodem transfer we sleep for 2 seconds
and then flush the line.  This allows all the magic bootparam
to be flushed from the line and makes the xmodem transfer reliable
and removes the Bad message failures.

Signed-off-by: Jon Nettleton <jon at solid-run.com>
Signed-off-by: Baruch Siach <baruch at tkos.co.il>
---
 tools/kwboot.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/tools/kwboot.c b/tools/kwboot.c
index 50ae2b4b77b1..4be094c9c8d8 100644
--- a/tools/kwboot.c
+++ b/tools/kwboot.c
@@ -286,6 +286,7 @@ kwboot_bootmsg(int tty, void *msg)
 {
 	int rc;
 	char c;
+	int count;
 
 	if (msg == NULL)
 		kwboot_printv("Please reboot the target into UART boot mode...");
@@ -297,10 +298,12 @@ kwboot_bootmsg(int tty, void *msg)
 		if (rc)
 			break;
 
-		rc = kwboot_tty_send(tty, msg, 8);
-		if (rc) {
-			usleep(msg_req_delay * 1000);
-			continue;
+		for (count = 0; count < 128; count++) {
+			rc = kwboot_tty_send(tty, msg, 8);
+			if (rc) {
+				usleep(msg_req_delay * 1000);
+				continue;
+			}
 		}
 
 		rc = kwboot_tty_recv(tty, &c, 1, msg_rsp_timeo);
@@ -426,6 +429,9 @@ kwboot_xmodem(int tty, const void *_data, size_t size)
 
 	kwboot_printv("Sending boot image...\n");
 
+	sleep(2); /* flush isn't effective without it */
+	tcflush(tty, TCIOFLUSH);
+
 	do {
 		struct kwboot_block block;
 		int n;
-- 
2.18.0