test: Add on-device unit test for STM32 RTC

BRANCH=none
BUG=b:151105339
TEST=make BOARD=bloonchipper test-stm32f_rtc -j
     Flash stm32f_rtc.bin and "runtest" in the console

Signed-off-by: Tom Hughes <tomhughes@chromium.org>
Change-Id: I3debfd93b62cb269ad61af0e4ca7e195554b5548
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2171569
Reviewed-by: Eric Yilun Lin <yllin@chromium.org>

board/hatch_fp/build.mk

@@ -20,3 +20,4 @@ test-list-y=\
        rtc \
        sha256 \
        sha256_unrolled \
+       stm32f_rtc \

board/nocturne_fp/build.mk

@@ -21,3 +21,4 @@ test-list-y=\
        rtc \
        sha256 \
        sha256_unrolled \
+       stm32f_rtc \

board/nucleo-dartmonkey/build.mk

@@ -19,3 +19,4 @@ test-list-y=\
        rtc \
        sha256 \
        sha256_unrolled \
+       stm32f_rtc \

board/nucleo-f412zg/build.mk

@@ -18,3 +18,4 @@ test-list-y=\
        rtc \
        sha256 \
        sha256_unrolled \
+       stm32f_rtc \

chip/stm32/clock-f.c

@@ -313,6 +313,7 @@ void reset_rtc_alarm(struct rtc_time_reg *rtc)
 	rtc_lock_regs();
 }
 
+test_mockable_static
 void __rtc_alarm_irq(void)
 {
 	struct rtc_time_reg rtc;

test/build.mk

@@ -151,6 +151,7 @@ sha256-y=sha256.o
 sha256_unrolled-y=sha256.o
 shmalloc-y=shmalloc.o
 static_if-y=static_if.o
+stm32f_rtc-y=stm32f_rtc.o
 stress-y=stress.o
 system-y=system.o
 thermal-y=thermal.o

test/stm32f_rtc.c

@@ -0,0 +1,52 @@
+/* Copyright 2020 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 "clock-f.h"
+#include "test_util.h"
+
+static volatile uint32_t rtc_fired;
+static struct rtc_time_reg rtc_irq;
+static const int rtc_delay_ms = 500;
+
+/* Override default RTC interrupt handler */
+void __rtc_alarm_irq(void)
+{
+	atomic_add(&rtc_fired, 1);
+	reset_rtc_alarm(&rtc_irq);
+}
+
+test_static int test_rtc_alarm(void)
+{
+	struct rtc_time_reg rtc;
+	uint32_t rtc_diff_us;
+	uint32_t rtc_diff_ms;
+	const int delay_us = rtc_delay_ms * MSEC;
+
+	set_rtc_alarm(0, delay_us, &rtc, 0);
+
+	msleep(2 * rtc_delay_ms);
+
+	/* Make sure the interrupt fired exactly once. */
+	TEST_EQ(1, atomic_read_clear(&rtc_fired), "%d");
+
+	rtc_diff_us = get_rtc_diff(&rtc, &rtc_irq);
+
+	ccprintf("rtc_diff_us: %d\n", rtc_diff_us);
+
+	/* Assume we'll always fire within 1 ms. May need to be adjusted if
+	 * this doesn't hold.
+	 */
+	rtc_diff_ms = rtc_diff_us / MSEC;
+	TEST_EQ(rtc_diff_ms, rtc_delay_ms, "%d");
+
+	return EC_SUCCESS;
+}
+
+void run_test(void)
+{
+	RUN_TEST(test_rtc_alarm);
+
+	test_print_result();
+}

test/stm32f_rtc.tasklist

@@ -0,0 +1,9 @@
+/* Copyright 2020 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.
+ */
+
+/**
+ * See CONFIG_TASK_LIST in config.h for details.
+ */
+#define CONFIG_TEST_TASK_LIST  /* no tasks */