Sleep HAL: add sleep manager API

Sleep manager provides API to lock/unlock deepsleep. This API allows a user to
control deep sleep.

This API should be done via atomic operations (to be IRQ/thread safe).

hal/mbed_sleep_manager.c

@@ -0,0 +1,71 @@
+/* mbed Microcontroller Library
+ * Copyright (c) 2017 ARM Limited
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "mbed_sleep.h"
+#include "mbed_critical.h"
+#include "sleep_api.h"
+#include "mbed_error.h"
+#include <limits.h>
+
+#if DEVICE_SLEEP
+
+// deep sleep locking counter. A target is allowed to deep sleep if counter == 0
+static uint16_t deep_sleep_lock = 0U;
+
+void sleep_manager_lock_deep_sleep(void)
+{
+    core_util_critical_section_enter();
+    if (deep_sleep_lock == USHRT_MAX) {
+        core_util_critical_section_exit();
+        error("Deep sleep lock would overflow (> USHRT_MAX)");
+    }
+    core_util_atomic_incr_u16(&deep_sleep_lock, 1);
+    core_util_critical_section_exit();
+}
+
+void sleep_manager_unlock_deep_sleep(void)
+{
+    core_util_critical_section_enter();
+    if (deep_sleep_lock == 0) {
+        core_util_critical_section_exit();
+        error("Deep sleep lock would underflow (< 0)");
+    }
+    core_util_atomic_decr_u16(&deep_sleep_lock, 1);
+    core_util_critical_section_exit();
+}
+
+bool sleep_manager_can_deep_sleep(void)
+{
+    return deep_sleep_lock == 0 ? true : false;
+}
+
+void sleep_manager_sleep_auto(void)
+{
+    core_util_critical_section_enter();
+// debug profile should keep debuggers attached, no deep sleep allowed
+#ifdef MBED_DEBUG
+    hal_sleep();
+#else
+    if (sleep_manager_can_deep_sleep()) {
+        hal_deepsleep();
+    } else {
+        hal_sleep();
+    }
+#endif
+    core_util_critical_section_exit();
+}
+
+#endif

platform/mbed_sleep.h

@@ -20,11 +20,87 @@
 #define MBED_SLEEP_H
 
 #include "sleep_api.h"
+#include "mbed_toolchain.h"
+#include <stdbool.h>
 
 #ifdef __cplusplus
 extern "C" {
 #endif
 
+/** Sleep manager API
+ * The sleep manager provides API to automatically select sleep mode.
+ *
+ * There are two sleep modes:
+ * - sleep
+ * - deepsleep
+ *
+ * Use locking/unlocking deepsleep for drivers that depend on features that
+ * are not allowed (=disabled) during the deepsleep. For instance, high frequency
+ * clocks.
+ *
+ * Example:
+ * @code
+ *
+ * void driver::handler()
+ * {
+ *     if (_sensor.get_event()) {
+ *         // any event - we are finished, unlock the deepsleep
+ *         sleep_manager_unlock_deep_sleep();
+ *         _callback();
+ *     }
+ * }
+ *
+ * int driver::measure(event_t event, callback_t& callback)
+ * {
+ *      _callback = callback;
+ *      sleep_manager_lock_deep_sleep();
+ *      // start async transaction, we are waiting for an event
+ *      return _sensor.start(event, callback);
+ * }
+ * @endcode
+ */
+
+/** Lock the deep sleep mode
+ *
+ * This locks the automatic deep mode selection. 
+ * sleep_manager_sleep_auto() will ignore deepsleep mode if
+ * this function is invoked at least once (the internal counter is non-zero)
+ *
+ * Use this locking mechanism for interrupt driven API that are
+ * running in the background and deepsleep could affect their functionality
+ * 
+ * The lock is a counter, can be locked up to USHRT_MAX
+ * This function is IRQ and thread safe
+ */
+void sleep_manager_lock_deep_sleep(void);
+
+/** Unlock the deep sleep mode
+ *
+ * Use unlocking in pair with sleep_manager_lock_deep_sleep(). 
+ * 
+ * The lock is a counter, should be equally unlocked as locked
+ * This function is IRQ and thread safe
+ */
+void sleep_manager_unlock_deep_sleep(void);
+
+/** Get the status of deep sleep allowance for a target
+ *
+ * @return true if a target can go to deepsleep, false otherwise
+ */
+bool sleep_manager_can_deep_sleep(void);
+
+/** Enter auto selected sleep mode. It chooses the sleep or deeepsleep modes based
+ *  on the deepsleep locking counter
+ *
+ * This function is IRQ and thread safe
+ *
+ * @note
+ * If MBED_DEBUG is defined, only hal_sleep is allowed. This ensures the debugger
+ * to be active for debug modes.
+ * 
+ */
+void sleep_manager_sleep_auto(void);
+
 /** Send the microcontroller to sleep
  *
  * @note This function can be a noop if not implemented by the platform.
@@ -46,11 +122,9 @@ extern "C" {
 __INLINE static void sleep(void)
 {
 #if !(defined(FEATURE_UVISOR) && defined(TARGET_UVISOR_SUPPORTED))
-#ifndef MBED_DEBUG
 #if DEVICE_SLEEP
-    hal_sleep();
+    sleep_manager_sleep_auto();
 #endif /* DEVICE_SLEEP */
-#endif /* MBED_DEBUG */
 #endif /* !(defined(FEATURE_UVISOR) && defined(TARGET_UVISOR_SUPPORTED)) */
 }
 
@@ -60,7 +134,7 @@ __INLINE static void sleep(void)
  * @note This function will be a noop in debug mode (debug build profile when MBED_DEBUG is defined)
  * @note This function will be a noop while uVisor is in use.
  *
- * This processor is setup ready for deep sleep, and sent to sleep using __WFI(). This mode
+ * This processor is setup ready for deep sleep, and sent to sleep. This mode
  * has the same sleep features as sleep plus it powers down peripherals and clocks. All state
  * is still maintained.
  *
@@ -71,14 +145,14 @@ __INLINE static void sleep(void)
  * Flash re-programming and the USB serial port will remain active, but the mbed program will no longer be
  * able to access the LocalFileSystem
  */
+
+MBED_DEPRECATED_SINCE("mbed-os-5.6", "One entry point for an application, use sleep()")
 __INLINE static void deepsleep(void)
 {
 #if !(defined(FEATURE_UVISOR) && defined(TARGET_UVISOR_SUPPORTED))
-#ifndef MBED_DEBUG
 #if DEVICE_SLEEP
-    hal_deepsleep();
+    sleep_manager_sleep_auto();
 #endif /* DEVICE_SLEEP */
-#endif /* MBED_DEBUG */
 #endif /* !(defined(FEATURE_UVISOR) && defined(TARGET_UVISOR_SUPPORTED)) */
 }