Import of the watch repository from Pebble

src/fw/kernel/util/stop.h

@@ -0,0 +1,76 @@
+/*
+ * Copyright 2024 Google LLC
+ *
+ * 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.
+ */
+
+#pragma once
+
+#include <stdbool.h>
+
+typedef enum {
+  InhibitorMain,
+  InhibitorDbgSerial,
+  InhibitorButton,
+  InhibitorBluetooth,
+  InhibitorDisplay,
+  InhibitorBacklight,
+  InhibitorCommMode,
+  InhibitorFlash,
+  InhibitorI2C1,
+  InhibitorI2C2,
+  InhibitorMic,
+  InhibitorAccessory,
+  InhibitorVibes,
+  InhibitorCompositor,
+  InhibitorI2C3,
+  InhibitorI2C4,
+  InhibitorBluetoothWatchdog,
+
+  InhibitorNumItems
+} StopModeInhibitor;
+
+/** Enter stop mode.
+ *
+ *  \note Probably no good reason to call this function from most application 
+ *  code. Let the FreeRTOS scheduler do its job.
+ */
+void enter_stop_mode(void);
+
+/** Prevent the scheduler from entering stop mode in idle.  Usually called when
+ * we know that there is some resource or peripheral being used that does not 
+ * require the use of the CPU, but that going into stop mode would interrupt.
+ * \note Internally this is implemented as a reference counter, so it is
+ * necessary to balance each call to disallow_stop_mode with a matching call to
+ * allow_stop_mode.
+ *  CAUTION: This function cannot be called at priorities > Systick
+ */
+void stop_mode_disable(StopModeInhibitor inhibitor);
+
+/** Allow the scheduler to enter stop mode in idle again.
+ *  CAUTION: This function cannot be called at priorities > Systick
+ */
+void stop_mode_enable(StopModeInhibitor inhibitor);
+
+//! Check whether we are permitted to go into stop mode
+bool stop_mode_is_allowed(void);
+
+
+//! Enable or disable sleep mode.
+//! Note: When sleep mode is disabled so is stop mode. When sleep mode is enabled, stop mode is
+//! controlled by stop_mode_is_allowed.
+void sleep_mode_enable(bool enable);
+
+//! Check whether we are permitted to go into sleep mode.
+bool sleep_mode_is_allowed(void);
+