From 2bcd5b1be10158a3e79c952b56c84b9d89958c3a Mon Sep 17 00:00:00 2001 From: =?utf8?q?Pali=20Roh=C3=A1r?= Date: Tue, 25 Jan 2022 18:13:08 +0100 Subject: [PATCH] tools: kwboot: Force BootROM to flush input queue after boot pattern MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Force the BootROM to flush its input queue after sending boot pattern. This ensures that after function kwboot_bootmsg() finishes, BootROM is able to start receiving xmodem packets without any specific delay or setup. Signed-off-by: Pali Rohár Signed-off-by: Marek Behún Reviewed-by: Stefan Roese --- tools/kwboot.c | 36 +++++++++++++++++++++++++++++++++++- 1 file changed, 35 insertions(+), 1 deletion(-) diff --git a/tools/kwboot.c b/tools/kwboot.c index c413a8b..824ae00 100644 --- a/tools/kwboot.c +++ b/tools/kwboot.c @@ -717,6 +717,7 @@ out: static int kwboot_bootmsg(int tty, void *msg) { + struct kwboot_block block; int rc; char c; int count; @@ -747,7 +748,40 @@ kwboot_bootmsg(int tty, void *msg) kwboot_printv("\n"); - return rc; + if (rc) + return rc; + + /* + * At this stage we have sent more boot message patterns and BootROM + * (at least on Armada XP and 385) started interpreting sent bytes as + * part of xmodem packets. If BootROM is expecting SOH byte as start of + * a xmodem packet and it receives byte 0xff, then it throws it away and + * sends a NAK reply to host. If BootROM does not receive any byte for + * 2s when expecting some continuation of the xmodem packet, it throws + * away the partially received xmodem data and sends NAK reply to host. + * + * Therefore for starting xmodem transfer we have two options: Either + * wait 2s or send 132 0xff bytes (which is the size of xmodem packet) + * to ensure that BootROM throws away any partially received data. + */ + + /* flush output queue with remaining boot message patterns */ + tcflush(tty, TCOFLUSH); + + /* send one xmodem packet with 0xff bytes to force BootROM to re-sync */ + memset(&block, 0xff, sizeof(block)); + kwboot_tty_send(tty, &block, sizeof(block), 0); + + /* + * Sending 132 bytes via 115200B/8-N-1 takes 11.45 ms, reading 132 bytes + * takes 11.45 ms, so waiting for 30 ms should be enough. + */ + usleep(30 * 1000); + + /* flush remaining NAK replies from input queue */ + tcflush(tty, TCIFLUSH); + + return 0; } static int -- 2.7.4