From: Antonio Borneo <borneo.antonio@gmail.com>
Date: Thu, 5 Mar 2020 16:00:50 +0000 (+0100)
Subject: driver/ftdi: skip trst in swd mode
X-Git-Tag: v0.11.0-rc2~6
X-Git-Url: https://review.openocd.org/gitweb?p=openocd.git;a=commitdiff_plain;h=0b248e04c1e58b374e82bad0361e42a5e8a96b77

driver/ftdi: skip trst in swd mode

When using the adapter olimex arm-jtag-swd (to convert to SWD a
JTAG-only FTDI adapter), the pin trst on JTAG side is re-used to
control the direction of pin SWDIO on SWD side.
There is a single reset API at adapter driver to assert/deassert
either srst and/or trst. A request to assert/deassert srst can
cause also trst to change value, hanging the SWD communication.

In SWD mode, ignore the value passed to trst.

Change-Id: I5fe1eed851177d405d77ae6079da9642dc1a08f1
Signed-off-by: Antonio Borneo <borneo.antonio@gmail.com>
Reviewed-on: http://openocd.zylin.com/6006
Tested-by: jenkins
---

diff --git a/src/jtag/drivers/ftdi.c b/src/jtag/drivers/ftdi.c
index 9d1c85cbd0..9e47d3cad1 100644
--- a/src/jtag/drivers/ftdi.c
+++ b/src/jtag/drivers/ftdi.c
@@ -524,17 +524,19 @@ static int ftdi_reset(int trst, int srst)
 
 	LOG_DEBUG_IO("reset trst: %i srst %i", trst, srst);
 
-	if (trst == 1) {
-		if (sig_ntrst)
-			ftdi_set_signal(sig_ntrst, '0');
-		else
-			LOG_ERROR("Can't assert TRST: nTRST signal is not defined");
-	} else if (sig_ntrst && jtag_get_reset_config() & RESET_HAS_TRST &&
-			trst == 0) {
-		if (jtag_get_reset_config() & RESET_TRST_OPEN_DRAIN)
-			ftdi_set_signal(sig_ntrst, 'z');
-		else
-			ftdi_set_signal(sig_ntrst, '1');
+	if (!swd_mode) {
+		if (trst == 1) {
+			if (sig_ntrst)
+				ftdi_set_signal(sig_ntrst, '0');
+			else
+				LOG_ERROR("Can't assert TRST: nTRST signal is not defined");
+		} else if (sig_ntrst && jtag_get_reset_config() & RESET_HAS_TRST &&
+				trst == 0) {
+			if (jtag_get_reset_config() & RESET_TRST_OPEN_DRAIN)
+				ftdi_set_signal(sig_ntrst, 'z');
+			else
+				ftdi_set_signal(sig_ntrst, '1');
+		}
 	}
 
 	if (srst == 1) {