From 38277fa75280071fb4e851de291b0274a457cea1 Mon Sep 17 00:00:00 2001 From: "Cliff L. Biffle" Date: Tue, 12 May 2020 13:28:04 -0700 Subject: [PATCH] jtag/drivers/stlink_usb: fix SWO prescaler The config_trace function has an out-parameter for generating the prescaler for the TPIU. The STLink implementation wasn't always writing it, causing the tpiu command to load uninitialized stack memory (minus one) into the TPIU's prescaler register when 'external' was requested. This change ensures that the out-parameter (and the other one, trace_freq, which hadn't caused any buggy behavior for me) are written every time. Signed-off-by: Cliff L. Biffle Change-Id: I222975869b1aa49cc6b1963c79d5ea0f46522b8c Reviewed-on: http://openocd.zylin.com/5656 Tested-by: jenkins Reviewed-by: Antonio Borneo --- src/jtag/drivers/stlink_usb.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/src/jtag/drivers/stlink_usb.c b/src/jtag/drivers/stlink_usb.c index ce55b94a55..bfc27f2aac 100644 --- a/src/jtag/drivers/stlink_usb.c +++ b/src/jtag/drivers/stlink_usb.c @@ -2996,12 +2996,8 @@ int stlink_config_trace(void *handle, bool enabled, return ERROR_FAIL; } - if (!enabled) { - stlink_usb_trace_disable(h); - return ERROR_OK; - } - - if (*trace_freq > STLINK_TRACE_MAX_HZ) { + /* Only concern ourselves with the frequency if the STlink is processing it. */ + if (enabled && *trace_freq > STLINK_TRACE_MAX_HZ) { LOG_ERROR("ST-LINK doesn't support SWO frequency higher than %u", STLINK_TRACE_MAX_HZ); return ERROR_FAIL; @@ -3024,6 +3020,10 @@ int stlink_config_trace(void *handle, bool enabled, } *prescaler = presc; + + if (!enabled) + return ERROR_OK; + h->trace.source_hz = *trace_freq; return stlink_usb_trace_enable(h); -- 2.30.2