module: timer: add API to update timer status without alarm

Some devices need overflow interrupt to update internal status. Add new
driver API to handle this if there is no acitve alarm.

Change-Id: I6a3106beb8dce8de7de29dfa5ff5742a9fd9692b
Signed-off-by: Joe Zhu <chunguang.zhu@verisilicon.com>

module/timer/include/mod_timer.h

@@ -1,6 +1,6 @@
 /*
  * Arm SCP/MCP Software
- * Copyright (c) 2017-2022, Arm Limited and Contributors. All rights reserved.
+ * Copyright (c) 2017-2024, Arm Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  *
@@ -120,6 +120,13 @@ struct mod_timer_driver_api {
 
     /*! Get counter frequency */
     int (*get_frequency)(fwk_id_t dev_id, uint32_t *value);
+
+    /*!
+     * Timer device may need to update internal status in alarm or overflow
+     * event. This handler is used to process overflow event when there is no
+     * active alarm. Optional
+     */
+    void (*overflow_handler)(fwk_id_t dev_id);
 };
 
 /*!

module/timer/src/mod_timer.c

@@ -1,6 +1,6 @@
 /*
  * Arm SCP/MCP Software
- * Copyright (c) 2017-2023, Arm Limited and Contributors. All rights reserved.
+ * Copyright (c) 2017-2024, Arm Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  *
@@ -557,8 +557,15 @@ static void timer_isr(uintptr_t ctx_ptr)
         (struct alarm_sub_element_ctx *)fwk_list_pop_head(&ctx->alarms_active);
 
     if (alarm == NULL) {
-        /* Timer interrupt triggered without any alarm in the active queue */
-        fwk_unexpected();
+        if (ctx->driver->overflow_handler != NULL) {
+            ctx->driver->overflow_handler(ctx->driver_dev_id);
+        } else {
+            /*
+             * Timer interrupt triggered without any alarm in the active queue nor an
+             * overflow handler provided.
+             */
+            fwk_unexpected();
+        }
         return;
     }