test: Add a test to check if the debugger is connected

This is intended to make it easier to debug the behavior of
is_debugger_connected(). With JLink we're seeing that C_DEBUGEN is still
set even after disconnecting the JLink (see referenced bug).

BRANCH=none
BUG=b:180945056
TEST=On dragonclaw v0.2 with JLink and servo_micro, flash the "debug"
     test:

     Connect the debugger:
     JLinkExe -device STM32F412CG -if SWD -speed 4000 -autoconnect 1
     J-Link>r
     J-Link>go

     Run the test on the FPMCU console:
     > runtest debugger
     => PASS

     Disconnect the debugger:
     J-Link>exit

     Run the test on the FPMCU console:
     > runtest no_debugger
     => PASS

TEST=On icetower v0.1 with JLink and servo_micro, flash the "debug"
     test:

     Connect the debugger:
     JLinkExe -device STM32H743ZI -if SWD -speed 4000 -autoconnect 1
     J-Link>r
     J-Link>go

     Run the test on the FPMCU console:
     > runtest debugger
     => PASS

     Physically disconnect the debugger and servo_micro. Then reconnect
     servo_micro and start servod.

     Run the test on the FPMCU console:
     > runtest no_debugger
     => PASS

Signed-off-by: Tom Hughes <tomhughes@chromium.org>
Change-Id: I544cab5814a30310345d4337a818d7b48cc22a8b
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/3739316
Reviewed-by: Bobby Casey <bobbycasey@google.com>

8 files changed, 63 insertions, 0 deletions

diff --git a/board/hatch_fp/build.mk b/board/hatch_fp/build.mk
index cdc2a59993..caac6f5822 100644
--- a/board/hatch_fp/build.mk
+++ b/board/hatch_fp/build.mk
@@ -31,6 +31,7 @@ test-list-y=\
        compile_time_macros \
        cortexm_fpu \
        crc \
+       debug \
        flash_physical \
        flash_write_protect \
        fpsensor \
diff --git a/board/nocturne_fp/build.mk b/board/nocturne_fp/build.mk
index 3401c92b8d..c24b9a0d0d 100644
--- a/board/nocturne_fp/build.mk
+++ b/board/nocturne_fp/build.mk
@@ -31,6 +31,7 @@ test-list-y=\
        compile_time_macros \
        cortexm_fpu \
        crc \
+       debug \
        flash_physical \
        flash_write_protect \
        fpsensor \
diff --git a/board/nucleo-dartmonkey/build.mk b/board/nucleo-dartmonkey/build.mk
index 67658498a0..dc3f1139ef 100644
--- a/board/nucleo-dartmonkey/build.mk
+++ b/board/nucleo-dartmonkey/build.mk
@@ -15,6 +15,7 @@ test-list-y=\
        cec \
        compile_time_macros \
        crc \
+       debug \
        flash_physical \
        flash_write_protect \
        fpsensor \
diff --git a/board/nucleo-f412zg/build.mk b/board/nucleo-f412zg/build.mk
index 6fa61ee41f..64a3472e5e 100644
--- a/board/nucleo-f412zg/build.mk
+++ b/board/nucleo-f412zg/build.mk
@@ -14,6 +14,7 @@ test-list-y=\
        cec \
        compile_time_macros \
        crc \
+       debug \
        flash_physical \
        flash_write_protect \
        mpu \
diff --git a/board/nucleo-h743zi/build.mk b/board/nucleo-h743zi/build.mk
index 2934125b32..b961c4841e 100644
--- a/board/nucleo-h743zi/build.mk
+++ b/board/nucleo-h743zi/build.mk
@@ -14,6 +14,7 @@ test-list-y=\
        cec \
        compile_time_macros \
        crc \
+       debug \
        flash_physical \
        flash_write_protect \
        mpu \
diff --git a/test/build.mk b/test/build.mk
index e7cc18d2e8..10e8f720f1 100644
--- a/test/build.mk
+++ b/test/build.mk
@@ -174,6 +174,7 @@ compile_time_macros-y=compile_time_macros.o
 console_edit-y=console_edit.o
 cortexm_fpu-y=cortexm_fpu.o
 crc-y=crc.o
+debug-y=debug.o
 entropy-y=entropy.o
 extpwr_gpio-y=extpwr_gpio.o
 fan-y=fan.o
diff --git a/test/debug.c b/test/debug.c
new file mode 100644
index 0000000000..0e4676b8b1
--- /dev/null
+++ b/test/debug.c
@@ -0,0 +1,48 @@
+/* Copyright 2022 The ChromiumOS Authors.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "common.h"
+#include "debug.h"
+#include "string.h"
+#include "test_util.h"
+
+static bool debugger_connected;
+
+static void print_usage(void)
+{
+	ccprintf("usage: runtest [debugger|no_debugger]\n");
+}
+
+test_static int test_debugger_is_connected(void)
+{
+	ccprintf("debugger_is_connected: %d\n", debugger_connected);
+	TEST_EQ(debugger_is_connected(), debugger_connected, "%d");
+	return EC_SUCCESS;
+}
+
+
+void run_test(int argc, char **argv)
+{
+	test_reset();
+
+	if (argc < 2) {
+		print_usage();
+		test_fail();
+		return;
+	}
+
+	if (strncmp(argv[1], "debugger", sizeof("debugger")) == 0)
+		debugger_connected = true;
+	else if (strncmp(argv[1], "no_debugger", sizeof("no_debugger")) == 0) {
+		debugger_connected = false;
+	} else {
+		print_usage();
+		test_fail();
+		return;
+	}
+
+	RUN_TEST(test_debugger_is_connected);
+	test_print_result();
+}
diff --git a/test/debug.tasklist b/test/debug.tasklist
new file mode 100644
index 0000000000..026dc51e90
--- /dev/null
+++ b/test/debug.tasklist
@@ -0,0 +1,9 @@
+/* Copyright 2022 The ChromiumOS Authors.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+/**
+ * See CONFIG_TASK_LIST in config.h for details.
+ */
+#define CONFIG_TEST_TASK_LIST