1 files changed, 52 insertions, 0 deletions
diff --git a/tests/qtest/cmsdk-apb-watchdog-test.c b/tests/qtest/cmsdk-apb-watchdog-test.c
index 950f64c527..2710cb17b8 100644
--- a/tests/qtest/cmsdk-apb-watchdog-test.c
+++ b/tests/qtest/cmsdk-apb-watchdog-test.c
@@ -15,6 +15,7 @@
  */
 
 #include "qemu/osdep.h"
+#include "qemu/bitops.h"
 #include "libqtest-single.h"
 
 /*
@@ -31,6 +32,11 @@
 #define WDOGMIS 0x14
 #define WDOGLOCK 0xc00
 
+#define SSYS_BASE 0x400fe000
+#define RCC 0x60
+#define SYSDIV_SHIFT 23
+#define SYSDIV_LENGTH 4
+
 static void test_watchdog(void)
 {
     g_assert_cmpuint(readl(WDOG_BASE + WDOGRIS), ==, 0);
@@ -61,6 +67,50 @@ static void test_watchdog(void)
     g_assert_cmpuint(readl(WDOG_BASE + WDOGRIS), ==, 0);
 }
 
+static void test_clock_change(void)
+{
+    uint32_t rcc;
+
+    /*
+     * Test that writing to the stellaris board's RCC register to
+     * change the system clock frequency causes the watchdog
+     * to change the speed it counts at.
+     */
+    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(80 * 500 + 1);
+    g_assert_cmpuint(readl(WDOG_BASE + WDOGRIS), ==, 0);
+    g_assert_cmpuint(readl(WDOG_BASE + WDOGVALUE), ==, 500);
+
+    /* Rewrite RCC.SYSDIV from 16 to 8, so the clock is now 40ns per tick */
+    rcc = readl(SSYS_BASE + RCC);
+    g_assert_cmpuint(extract32(rcc, SYSDIV_SHIFT, SYSDIV_LENGTH), ==, 0xf);
+    rcc = deposit32(rcc, SYSDIV_SHIFT, SYSDIV_LENGTH, 7);
+    writel(SSYS_BASE + RCC, rcc);
+
+    /* Just past the 1000th tick: timer should have fired */
+    clock_step(40 * 500);
+    g_assert_cmpuint(readl(WDOG_BASE + WDOGRIS), ==, 1);
+
+    g_assert_cmpuint(readl(WDOG_BASE + WDOGVALUE), ==, 0);
+
+    /* VALUE reloads at following tick */
+    clock_step(41);
+    g_assert_cmpuint(readl(WDOG_BASE + WDOGVALUE), ==, 1000);
+
+    /* Writing any value to WDOGINTCLR clears the interrupt and reloads */
+    clock_step(40 * 500);
+    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;
@@ -70,6 +120,8 @@ int main(int argc, char **argv)
     qtest_start("-machine lm3s811evb");
 
     qtest_add_func("/cmsdk-apb-watchdog/watchdog", test_watchdog);
+    qtest_add_func("/cmsdk-apb-watchdog/watchdog_clock_change",
+                   test_clock_change);
 
     r = g_test_run();