cts: Add timer test

The timer test checks the accuracy of the internal timer. After sync,
DUT and TH start counting down one second. After one second, DUT raises
GPIO level.  TH determines whether the test passes or not based on how
much more or less time elapsed than one second, assuming its clock is
calibrated.

This test takes advantage of TH running on a bare chip. If the host
were measuring (instead of TH), the timing would be affected by many
software and hardware layers (e.g. UART drivers on DUT and host,
python interpreter, etc.).

BUG=chromium:624520
BRANCH=none
TEST=cts.py --module timer && cts.py --module gpio && make buildall

Change-Id: I535e7772b4d93f1f5d248506f7ea167429a50174
Signed-off-by: Daisuke Nojiri <dnojiri@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/361384

4 files changed, 144 insertions, 0 deletions

diff --git a/cts/build.mk b/cts/build.mk
index 59fa85547c..8d132e8da2 100644
--- a/cts/build.mk
+++ b/cts/build.mk
@@ -5,6 +5,10 @@
 
 CFLAGS_CTS=-DCTS_MODULE -DCTS_TASKFILE=cts.tasklist
 
+ifeq "$(CTS_MODULE)" "gpio"
+CFLAGS_CTS+=-DCTS_MODULE_GPIO
+endif
+
 ifeq ($(BOARD),stm32l476g-eval)
 	cts-y+=$(CTS_MODULE)/th.o
 	cts-y+=common/th_common.o
diff --git a/cts/timer/cts.testlist b/cts/timer/cts.testlist
new file mode 100644
index 0000000000..d4cb3c30b3
--- /dev/null
+++ b/cts/timer/cts.testlist
@@ -0,0 +1,19 @@
+/* Copyright 2016 The Chromium OS Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+/*
+ * Test timer accuracy
+ *
+ * After sync, DUT and TH start counting down one second. After one second,
+ * DUT raises GPIO level, which triggers an interrupt on TH. TH determines
+ * whether the test passes or not based on how much more or less time elapsed
+ * than one second.
+ *
+ * Requirements:
+ * - Sync connection
+ * - GPIO_OUTPUT connection for sending notification from DUT
+ * - Calibrated TH timer
+ */
+CTS_TEST(timer_calibration_test)
diff --git a/cts/timer/dut.c b/cts/timer/dut.c
new file mode 100644
index 0000000000..29003f36af
--- /dev/null
+++ b/cts/timer/dut.c
@@ -0,0 +1,44 @@
+/* Copyright 2016 The Chromium OS Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "common.h"
+#include "dut_common.h"
+#include "gpio.h"
+#include "timer.h"
+#include "watchdog.h"
+
+static enum cts_rc timer_calibration_test(void)
+{
+	gpio_set_flags(GPIO_OUTPUT_TEST, GPIO_ODR_HIGH);
+
+	sync();
+	usleep(SECOND);
+	gpio_set_level(GPIO_OUTPUT_TEST, 0);
+
+	return CTS_RC_SUCCESS;
+}
+
+#include "cts_testlist.h"
+
+void cts_task(void)
+{
+	enum cts_rc rc;
+	int i;
+
+	for (i = 0; i < CTS_TEST_ID_COUNT; i++) {
+		sync();
+		rc = tests[i].run();
+		CPRINTF("\n%s %d\n", tests[i].name, rc);
+		cflush();
+	}
+
+	CPRINTS("Timer test suite finished");
+	cflush();
+
+	while (1) {
+		watchdog_reload();
+		sleep(1);
+	}
+}
diff --git a/cts/timer/th.c b/cts/timer/th.c
new file mode 100644
index 0000000000..a6e9d575b1
--- /dev/null
+++ b/cts/timer/th.c
@@ -0,0 +1,77 @@
+/* Copyright 2016 The Chromium OS Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "common.h"
+#include "gpio.h"
+#include "registers.h"
+#include "task.h"
+#include "th_common.h"
+#include "timer.h"
+#include "watchdog.h"
+
+/*
+ * Interrupt handler
+ *
+ * DUT is supposed to trigger an interrupt when it's done counting down,
+ * causing this function to be invoked.
+ */
+void cts_irq(enum gpio_signal signal)
+{
+	/* Wake up the CTS task */
+	task_wake(TASK_ID_CTS);
+}
+
+static enum cts_rc timer_calibration_test(void)
+{
+	/* Error margin: +/-2 msec (0.2% for one second) */
+	const int32_t margin = 2 * MSEC;
+	int32_t elapsed, delta;
+	timestamp_t t0, t1;
+
+	gpio_enable_interrupt(GPIO_CTS_NOTIFY);
+	interrupt_enable();
+
+	sync();
+	t0 = get_time();
+	/* Wait for interrupt */
+	task_wait_event(-1);
+	t1 = get_time();
+
+	elapsed = (int32_t)(t1.val - t0.val);
+	delta = elapsed - SECOND;
+	if (delta < -margin) {
+		CPRINTS("DUT clock runs too fast: %+d usec", delta);
+		return CTS_RC_FAILURE;
+	}
+	if (margin < delta) {
+		CPRINTS("DUT clock runs too slow: %+d usec", delta);
+		return CTS_RC_FAILURE;
+	}
+
+	return CTS_RC_SUCCESS;
+}
+
+#include "cts_testlist.h"
+
+void cts_task(void)
+{
+	enum cts_rc rc;
+	int i;
+
+	for (i = 0; i < CTS_TEST_ID_COUNT; i++) {
+		sync();
+		rc = tests[i].run();
+		CPRINTF("\n%s %d\n", tests[i].name, rc);
+		cflush();
+	}
+
+	CPRINTS("Timer test suite finished");
+	cflush();
+
+	while (1) {
+		watchdog_reload();
+		sleep(1);
+	}
+}