@@ -0,0 +1,152 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * KUnit tests for RV hybrid automata (HA) framework
+ */
+#include <kunit/test.h>
+#include <linux/rv.h>
+
+#if IS_ENABLED(CONFIG_RV_HA_MONITOR)
+
+#include <rv_trace.h>
+
+/* rvtest: a minimal per-object HA monitor driven directly by the tests. */
+#define MONITOR_NAME rvtest
+#define RV_MON_TYPE RV_MON_PER_OBJ
+#define HA_TIMER_TYPE HA_TIMER_HRTIMER
+typedef void *monitor_target;
+
+#define rv_monitoring_on() true
+#define trace_rv_retries_error(...) do { } while (0)
+#define trace_event_rvtest(...) do { } while (0)
+#define trace_error_rvtest(...) do { } while (0)
+#define trace_error_env_rvtest(...) do { } while (0)
+
+enum states_rvtest {
+ idle_rvtest,
+ armed_rvtest,
+ state_max_rvtest,
+};
+
+#define INVALID_STATE state_max_rvtest
+
+enum events_rvtest {
+ start_rvtest,
+ event_max_rvtest,
+};
+
+enum envs_rvtest {
+ clk_rvtest,
+ env_max_rvtest,
+ env_max_stored_rvtest = env_max_rvtest,
+};
+
+#define HA_CLK_NS
+
+struct automaton_rvtest {
+ char *state_names[state_max_rvtest];
+ char *event_names[event_max_rvtest];
+ char *env_names[env_max_rvtest];
+ unsigned char function[state_max_rvtest][event_max_rvtest];
+ unsigned char initial_state;
+ bool final_states[state_max_rvtest];
+};
+
+static const struct automaton_rvtest automaton_rvtest = {
+ .state_names = { "idle", "armed" },
+ .event_names = { "start" },
+ .env_names = { "clk" },
+ .function = {
+ { armed_rvtest }, /* idle */
+ { INVALID_STATE }, /* armed */
+ },
+ .initial_state = idle_rvtest,
+ .final_states = { 1, 0 },
+};
+
+#include <rv/ha_monitor.h>
+
+#define RVTEST_BUDGET_NS (300ULL * NSEC_PER_MSEC)
+
+static u64 ha_get_env(struct ha_monitor *ha_mon, enum envs_rvtest env,
+ u64 time_ns)
+{
+ return ha_get_clk_ns(ha_mon, env, time_ns);
+}
+
+static void ha_reset_env(struct ha_monitor *ha_mon, enum envs_rvtest env,
+ u64 time_ns)
+{
+ ha_reset_clk_ns(ha_mon, env, time_ns);
+}
+
+static bool ha_verify_constraint(struct ha_monitor *ha_mon,
+ enum states curr_state, enum events event,
+ enum states next_state, u64 time_ns)
+{
+ return true;
+}
+
+static const struct rv_kunit_mon rvtest_mon __maybe_unused = RV_MON_OPS_INIT();
+
+/*
+ * rv_test_rvtest_underflow - the HA clock math must not underflow as u64
+ *
+ * An invariant checked while the uptime is below the budget holds, and a
+ * timer armed after the budget elapsed expires now.
+ */
+static void rv_test_rvtest_underflow(struct kunit *test)
+{
+ struct ha_monitor *ha_mon;
+ struct da_monitor *da_mon;
+ const int id = 4242;
+
+ da_monitor_init();
+ rv_this.enabled = 1;
+
+ da_handle_start_run_event(id, NULL, start_rvtest);
+
+ scoped_guard(rcu)
+ da_mon = da_get_monitor(id, NULL);
+ KUNIT_ASSERT_NOT_NULL(test, da_mon);
+ ha_mon = to_ha_monitor(da_mon);
+
+ /* Uptime below the budget: time_ns - expire_ns would underflow. */
+ ha_reset_clk_ns(ha_mon, clk_rvtest, 0);
+ KUNIT_EXPECT_TRUE(test, ha_check_invariant_ns(ha_mon, clk_rvtest, 0,
+ RVTEST_BUDGET_NS));
+
+ /*
+ * Budget already elapsed: expire - passed would underflow and queue
+ * the timer at KTIME_SEC_MAX. Reset first so the expiry does not
+ * report.
+ */
+ da_monitor_reset(&ha_mon->da_mon);
+ ha_reset_clk_ns(ha_mon, clk_rvtest, 0);
+ ha_start_timer_ns(ha_mon, clk_rvtest, RVTEST_BUDGET_NS,
+ RVTEST_BUDGET_NS + NSEC_PER_SEC);
+ KUNIT_EXPECT_TRUE(test,
+ ktime_before(hrtimer_get_expires(&ha_mon->hrtimer),
+ ktime_get() + NSEC_PER_SEC));
+
+ ha_cancel_timer_sync(ha_mon);
+ da_destroy_storage(id);
+ da_monitor_destroy();
+ rv_this.enabled = 0;
+}
+
+static struct kunit_case rv_ha_kunit_cases[] = {
+ KUNIT_CASE(rv_test_rvtest_underflow),
+ {}
+};
+
+static struct kunit_suite rv_ha_kunit_suite = {
+ .name = "rv_ha",
+ .test_cases = rv_ha_kunit_cases,
+};
+
+kunit_test_suite(rv_ha_kunit_suite);
+
+#endif /* CONFIG_RV_HA_MONITOR */
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("KUnit tests for RV hybrid automata (HA) framework");