arm_tpiu_swo: fix autodetection of SWO pin frequency

While the documentation reports that SWO pin frequency can be
omitted to let the adapter autodetect the value, the code wrongly
drops an error when pin frequency is not specified.

Don't require the pin frequency to be set at "enable", but verify
that the adapter has properly changes it to a valid value.

Change-Id: I3dfbe3256e8887ef4f03512769b06381cdc9db0d
Signed-off-by: Antonio Borneo <borneo.antonio@gmail.com>
Reported-by: Karl Palsson <karlp@tweak.net.au>
Fixes: 184724d14e12 ("arm_tpiu_swo: add support for independent TPIU and SWO")
Reviewed-on: https://review.openocd.org/c/openocd/+/6310
Tested-by: jenkins
Reviewed-by: zapb <dev@zapb.de>

diff --git a/src/target/arm_tpiu_swo.c b/src/target/arm_tpiu_swo.c
index a0eba6782d972a16ac3f018cf136a2ebc9464d85..fba3fec4f25be74112b0e3438d14626a9d237870 100644 (file)
--- a/src/target/arm_tpiu_swo.c
+++ b/src/target/arm_tpiu_swo.c
@@ -625,10 +625,8 @@ static int jim_arm_tpiu_swo_enable(Jim_Interp *interp, int argc, Jim_Obj *const
        }
 
        if (obj->pin_protocol == TPIU_SPPR_PROTOCOL_MANCHESTER || obj->pin_protocol == TPIU_SPPR_PROTOCOL_UART)
-               if (!obj->swo_pin_freq) {
-                       LOG_ERROR("SWO pin frequency not set");
-                       return JIM_ERR;
-               }
+               if (!obj->swo_pin_freq)
+                       LOG_DEBUG("SWO pin frequency not set, will be autodetected by the adapter");
 
        struct target *target = get_current_target(cmd_ctx);
 
@@ -731,6 +729,17 @@ static int jim_arm_tpiu_swo_enable(Jim_Interp *interp, int argc, Jim_Obj *const
                        return JIM_ERR;
                }
 
+               if (obj->pin_protocol == TPIU_SPPR_PROTOCOL_MANCHESTER || obj->pin_protocol == TPIU_SPPR_PROTOCOL_UART)
+                       if (!swo_pin_freq) {
+                               if (obj->swo_pin_freq)
+                                       LOG_ERROR("Adapter rejected SWO pin frequency %d Hz", obj->swo_pin_freq);
+                               else
+                                       LOG_ERROR("Adapter does not support auto-detection of SWO pin frequency nor a default value");
+
+                               arm_tpiu_swo_close_output(obj);
+                               return JIM_ERR;
+                       }
+
                if (obj->swo_pin_freq != swo_pin_freq)
                        LOG_INFO("SWO pin data rate adjusted by adapter to %d Hz", swo_pin_freq);
                obj->swo_pin_freq = swo_pin_freq;