From 48b3ea66cae97a06c35f117be8613c597aa2fca8 Mon Sep 17 00:00:00 2001
From: =?utf8?q?Pali=20Roh=C3=A1r?= <pali@kernel.org>
Date: Fri, 24 Sep 2021 23:06:50 +0200
Subject: [PATCH] tools: kwboot: Allow non-xmodem text output from BootROM only
 in a specific case
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When sending image header / image data, BootROM does not send any
non-xmodem text output. We should therefore interpret unknown bytes in
the xmodem protocol as errors and resend current packet. This should
improve the transfer in case there are errors on the UART line.

Text output from BootROM may only happen after whole image header is
sent and before ACK for the last packet of image header is received.
In this case BootROM may execute code from the image, which may interact
with UART (U-Boot SPL, for example, prints stuff on UART).

Print received non-xmodem output from BootROM only in this case.

Signed-off-by: Pali Rohár <pali@kernel.org>
[ refactored & simplified ]
Signed-off-by: Marek Behún <marek.behun@nic.cz>
Reviewed-by: Stefan Roese <sr@denx.de>
---
 tools/kwboot.c | 70 ++++++++++++++++++++++++++++++++++++++------------
 1 file changed, 53 insertions(+), 17 deletions(-)

diff --git a/tools/kwboot.c b/tools/kwboot.c
index 2e5684b91c..4636622a6c 100644
--- a/tools/kwboot.c
+++ b/tools/kwboot.c
@@ -382,33 +382,62 @@ _is_xm_reply(char c)
 }
 
 static int
-kwboot_xm_sendblock(int fd, struct kwboot_block *block)
+kwboot_xm_recv_reply(int fd, char *c, int allow_non_xm)
+{
+	int rc;
+
+	while (1) {
+		rc = kwboot_tty_recv(fd, c, 1, blk_rsp_timeo);
+		if (rc) {
+			if (errno != ETIMEDOUT)
+				return rc;
+			*c = NAK;
+		}
+
+		/* If received xmodem reply, end. */
+		if (_is_xm_reply(*c))
+			break;
+
+		/*
+		 * If printing non-xmodem text output is allowed and such a byte
+		 * was received, print it.
+		 */
+		if (allow_non_xm) {
+			putchar(*c);
+			fflush(stdout);
+		}
+	}
+
+	return 0;
+}
+
+static int
+kwboot_xm_sendblock(int fd, struct kwboot_block *block, int allow_non_xm,
+		    int *done_print)
 {
 	int rc, retries;
 	char c;
 
+	*done_print = 0;
+
 	retries = 16;
 	do {
 		rc = kwboot_tty_send(fd, block, sizeof(*block));
 		if (rc)
 			return rc;
 
-		do {
-			rc = kwboot_tty_recv(fd, &c, 1, blk_rsp_timeo);
-			if (rc) {
-				if (errno != ETIMEDOUT)
-					return rc;
-				c = NAK;
-			}
-
-			if (!_is_xm_reply(c))
-				printf("%c", c);
+		if (allow_non_xm && !*done_print) {
+			kwboot_progress(100, '.');
+			kwboot_printv("Done\n");
+			*done_print = 1;
+		}
 
-		} while (!_is_xm_reply(c));
+		rc = kwboot_xm_recv_reply(fd, &c, allow_non_xm);
+		if (rc)
+			return rc;
 
-		if (c != ACK)
+		if (!allow_non_xm && c != ACK)
 			kwboot_progress(-1, '+');
-
 	} while (c == NAK && retries-- > 0);
 
 	rc = -1;
@@ -435,6 +464,7 @@ static int
 kwboot_xmodem_one(int tty, int *pnum, int header, const uint8_t *data,
 		  size_t size)
 {
+	int done_print = 0;
 	size_t sent, left;
 	int rc;
 
@@ -446,22 +476,28 @@ kwboot_xmodem_one(int tty, int *pnum, int header, const uint8_t *data,
 
 	while (sent < size) {
 		struct kwboot_block block;
+		int last_block;
 		size_t blksz;
 
 		blksz = kwboot_xm_makeblock(&block, data, left, (*pnum)++);
 		data += blksz;
 
-		rc = kwboot_xm_sendblock(tty, &block);
+		last_block = (left <= blksz);
+
+		rc = kwboot_xm_sendblock(tty, &block, header && last_block,
+					 &done_print);
 		if (rc)
 			goto out;
 
 		sent += blksz;
 		left -= blksz;
 
-		kwboot_progress(sent * 100 / size, '.');
+		if (!done_print)
+			kwboot_progress(sent * 100 / size, '.');
 	}
 
-	kwboot_printv("Done\n");
+	if (!done_print)
+		kwboot_printv("Done\n");
 
 	return 0;
 out:
-- 
2.39.5