zephyr: tests: Delay post-main tests until hooks finish

Add a semaphore mechanism to test_main() that delays execution of the
post-main tests until the last `HOOK_CHIPSET_STARTUP` hook has
completed. This allows certain drivers to finish initializing before
tests run, eliminating a pesky race condition.

This only affects tests under `zephyr/test/drivers`

BRANCH=None
BUG=None
TEST=./twister -T zephyr/test/drivers

Signed-off-by: Tristan Honscheid <honscheid@google.com>
Change-Id: I2f79cb2bde7d3c1326070992a03d3b556774e3a7
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/3892153
Reviewed-by: Abe Levkoy <alevkoy@chromium.org>
Code-Coverage: Zoss <zoss-cl-coverage@prod.google.com>

1 files changed, 28 insertions, 0 deletions

diff --git a/zephyr/test/drivers/common/src/main.c b/zephyr/test/drivers/common/src/main.c
index 978c699d24..1c8497ab3f 100644
--- a/zephyr/test/drivers/common/src/main.c
+++ b/zephyr/test/drivers/common/src/main.c
@@ -6,8 +6,25 @@
 #include <zephyr/kernel.h>
 #include <zephyr/ztest.h>
 #include "ec_app_main.h"
+#include "hooks.h"
 #include "test/drivers/test_state.h"
 
+/**
+ * @brief Semaphore that signals when hooks have completed
+ */
+static struct k_sem init_hooks_completed;
+
+/**
+ * @brief Hook callback function. Gets registered with the lowest priority so
+ *        that we know all actual hooks have finished. Increments the semaphore.
+ */
+static void hook_completed_callback(void)
+{
+	/* Signal that hooks are completed */
+	k_sem_give(&init_hooks_completed);
+}
+DECLARE_HOOK(HOOK_CHIPSET_STARTUP, hook_completed_callback, HOOK_PRIO_LAST);
+
 bool drivers_predicate_pre_main(const void *state)
 {
 	return ((struct test_state *)state)->ec_app_main_run == false;
@@ -20,6 +37,8 @@ bool drivers_predicate_post_main(const void *state)
 
 void test_main(void)
 {
+	k_sem_init(&init_hooks_completed, 0, 1);
+
 	struct test_state state = {
 		.ec_app_main_run = false,
 	};
@@ -30,6 +49,15 @@ void test_main(void)
 	ec_app_main();
 	state.ec_app_main_run = true;
 
+/* Delay the post-main tests until hooks finish. Allow a generous
+ * timeout before failing. Tests with mocked power states interfere
+ * with this mechanism, so proceed normally in this case.
+ */
+#if !IS_ENABLED(CONFIG_POWER_SEQUENCE_MOCK)
+	zassert_ok(k_sem_take(&init_hooks_completed, K_SECONDS(10)),
+		   "Timed out waiting for hooks to finish");
+#endif /* !IS_ENABLED(CONFIG_POWER_SEQUENCE_MOCK) */
+
 	/* Run all the suites that depend on main being called */
 	ztest_run_all(&state);
 }