tests: Add a simple test of the CMSDK APB watchdog

Add a simple test of the CMSDK watchdog, since we're about to do some
refactoring of how it is clocked.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Luc Michel <luc@lmichel.fr>
Tested-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-id: 20210128114145.20536-5-peter.maydell@linaro.org
Message-id: 20210121190622.22000-5-peter.maydell@linaro.org
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>

MAINTAINERS

@@ -588,6 +588,7 @@ F: hw/char/cmsdk-apb-uart.c
 F: include/hw/char/cmsdk-apb-uart.h
 F: hw/watchdog/cmsdk-apb-watchdog.c
 F: include/hw/watchdog/cmsdk-apb-watchdog.h
+F: tests/qtest/cmsdk-apb-watchdog-test.c
 F: hw/misc/tz-ppc.c
 F: include/hw/misc/tz-ppc.h
 F: hw/misc/tz-mpc.c

tests/qtest/cmsdk-apb-watchdog-test.c

@@ -0,0 +1,79 @@
+/*
+ * QTest testcase for the CMSDK APB watchdog device
+ *
+ * Copyright (c) 2021 Linaro Limited
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * for more details.
+ */
+
+#include "qemu/osdep.h"
+#include "libqtest-single.h"
+
+/*
+ * lm3s811evb watchdog; at board startup this runs at 200MHz / 16 == 12.5MHz,
+ * which is 80ns per tick.
+ */
+#define WDOG_BASE 0x40000000
+
+#define WDOGLOAD 0
+#define WDOGVALUE 4
+#define WDOGCONTROL 8
+#define WDOGINTCLR 0xc
+#define WDOGRIS 0x10
+#define WDOGMIS 0x14
+#define WDOGLOCK 0xc00
+
+static void test_watchdog(void)
+{
+    g_assert_cmpuint(readl(WDOG_BASE + WDOGRIS), ==, 0);
+
+    writel(WDOG_BASE + WDOGCONTROL, 1);
+    writel(WDOG_BASE + WDOGLOAD, 1000);
+
+    /* Step to just past the 500th tick */
+    clock_step(500 * 80 + 1);
+    g_assert_cmpuint(readl(WDOG_BASE + WDOGRIS), ==, 0);
+    g_assert_cmpuint(readl(WDOG_BASE + WDOGVALUE), ==, 500);
+
+    /* Just past the 1000th tick: timer should have fired */
+    clock_step(500 * 80);
+    g_assert_cmpuint(readl(WDOG_BASE + WDOGRIS), ==, 1);
+    g_assert_cmpuint(readl(WDOG_BASE + WDOGVALUE), ==, 0);
+
+    /* VALUE reloads at following tick */
+    clock_step(80);
+    g_assert_cmpuint(readl(WDOG_BASE + WDOGVALUE), ==, 1000);
+
+    /* Writing any value to WDOGINTCLR clears the interrupt and reloads */
+    clock_step(500 * 80);
+    g_assert_cmpuint(readl(WDOG_BASE + WDOGVALUE), ==, 500);
+    g_assert_cmpuint(readl(WDOG_BASE + WDOGRIS), ==, 1);
+    writel(WDOG_BASE + WDOGINTCLR, 0);
+    g_assert_cmpuint(readl(WDOG_BASE + WDOGVALUE), ==, 1000);
+    g_assert_cmpuint(readl(WDOG_BASE + WDOGRIS), ==, 0);
+}
+
+int main(int argc, char **argv)
+{
+    int r;
+
+    g_test_init(&argc, &argv, NULL);
+
+    qtest_start("-machine lm3s811evb");
+
+    qtest_add_func("/cmsdk-apb-watchdog/watchdog", test_watchdog);
+
+    r = g_test_run();
+
+    qtest_end();
+
+    return r;
+}

tests/qtest/meson.build

@@ -143,6 +143,7 @@ qtests_npcm7xx = \
    'npcm7xx_watchdog_timer-test']
 qtests_arm = \
   (config_all_devices.has_key('CONFIG_CMSDK_APB_TIMER') ? ['cmsdk-apb-timer-test'] : []) + \
+  (config_all_devices.has_key('CONFIG_CMSDK_APB_WATCHDOG') ? ['cmsdk-apb-watchdog-test'] : []) + \
   (config_all_devices.has_key('CONFIG_PFLASH_CFI02') ? ['pflash-cfi02-test'] : []) +         \
   (config_all_devices.has_key('CONFIG_NPCM7XX') ? qtests_npcm7xx : []) + \
   ['arm-cpu-features',