drivers: wdt: add implementation of SMCWD_GET_TIMELEFT

Implement watchdog SMC service SMCWD_GET_TIMELEFT that is optional and allows non-secure world to get information on watchdog state. The service is supported by new watchdog driver operation handler get_timeleft. Signed-off-by: Antonio Borneo <[email protected]> Signed-off-by: Etienne Carriere <[email protected]>
etienne-lms · Dec 18, 2023 · d0bb06c · d0bb06c
1 parent 56bec2d
commit d0bb06c
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Showing 2 changed files with 32 additions and 0 deletions.
diff --git a/core/drivers/wdt/watchdog_sm.c b/core/drivers/wdt/watchdog_sm.c
@@ -20,6 +20,8 @@ enum sm_handler_ret __wdt_sm_handler(struct thread_smc_args *args)
 	uint32_t exceptions = 0;
 	unsigned long min_timeout = 0;
 	unsigned long max_timeout = 0;
+	unsigned long timeleft = 0;
+	bool is_enabled = false;
 
 	switch (args->a1) {
 	case SMCWD_INIT:
@@ -66,6 +68,18 @@ enum sm_handler_ret __wdt_sm_handler(struct thread_smc_args *args)
 		break;
 	/* SMCWD_GET_TIMELEFT is optional */
 	case SMCWD_GET_TIMELEFT:
+		res = watchdog_gettimeleft(&is_enabled, &timeleft);
+		if (res == TEE_ERROR_NOT_SUPPORTED) {
+			args->a0 = PSCI_RET_NOT_SUPPORTED;
+		} else if (res) {
+			args->a0 = PSCI_RET_INTERNAL_FAILURE;
+		} else if (!is_enabled) {
+			args->a0 = PSCI_RET_DISABLED;
+		} else {
+			args->a0 = PSCI_RET_SUCCESS;
+			args->a1 = timeleft;
+		}
+		break;
 	default:
 		args->a0 = PSCI_RET_NOT_SUPPORTED;
 	}

diff --git a/core/include/drivers/wdt.h b/core/include/drivers/wdt.h
@@ -26,6 +26,8 @@ struct wdt_chip {
  * @ping:	The routine that sends a keepalive ping to the watchdog device.
  * @set_timeout:The routine that finds the load value that will reset system in
  * required timeout (in seconds).
+ * @get_timeleft:The routine that finds if the watchdog is already started and
+ * the time left (in seconds) before the watchdog timeouts.
  *
  * The wdt_ops structure contains a list of low-level operations
  * that control a watchdog device.
@@ -37,6 +39,8 @@ struct wdt_ops {
 	void (*stop)(struct wdt_chip *chip);
 	void (*ping)(struct wdt_chip *chip);
 	TEE_Result (*set_timeout)(struct wdt_chip *chip, unsigned long timeout);
+	TEE_Result (*get_timeleft)(struct wdt_chip *chip, bool *is_enabled,
+				   unsigned long *timeleft);
 };
 
 #ifdef CFG_WDT
@@ -80,6 +84,15 @@ static inline void watchdog_settimeout(unsigned long timeout)
 	if (wdt_chip)
 		wdt_chip->ops->set_timeout(wdt_chip, timeout);
 }
+
+static inline TEE_Result watchdog_gettimeleft(bool *is_enabled,
+					      unsigned long *timeleft)
+{
+	if (!wdt_chip || !wdt_chip->ops->get_timeleft)
+		return TEE_ERROR_NOT_SUPPORTED;
+
+	return wdt_chip->ops->get_timeleft(wdt_chip, is_enabled, timeleft);
+}
 #else
 static inline TEE_Result watchdog_register(struct wdt_chip *chip __unused)
 {
@@ -96,6 +109,11 @@ static inline void watchdog_start(void) {}
 static inline void watchdog_stop(void) {}
 static inline void watchdog_ping(void) {}
 static inline void watchdog_settimeout(unsigned long timeout __unused) {}
+static inline TEE_Result watchdog_gettimeleft(bool *is_enabled __unused,
+					      unsigned long *timeleft __unused)
+{
+	return TEE_ERROR_NOT_SUPPORTED;
+}
 #endif
 
 #ifdef CFG_WDT_SM_HANDLER