Add a sub-HAL implementation for testing multi-HAL
Creates a fake sub-HAL using the default implementation for sensors HAL
2.0 with some small modifications to support the multi-HAL interface.
This sub-HAL can be configured to support two different sets of sensors
making it easier to build and load two different sub-HAL implementations
onto device and verify the multihal implementation works.
Bug: 136511617
Test: compile only. Once multihal can load in sub-HALs, then this can be
accurately tested.
Change-Id: I9b136506bdbc8a3b196fd363748bddfcdd564daf
diff --git a/sensors/2.0/multihal/include/SubHal.h b/sensors/2.0/multihal/include/SubHal.h
new file mode 100644
index 0000000..75e93a1
--- /dev/null
+++ b/sensors/2.0/multihal/include/SubHal.h
@@ -0,0 +1,202 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * 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 <android/hardware/sensors/1.0/types.h>
+#include <android/hardware/sensors/2.0/ISensors.h>
+
+#include <vector>
+
+using ::android::hardware::sensors::V1_0::Event;
+using ::android::hardware::sensors::V1_0::Result;
+using ::android::hardware::sensors::V1_0::SensorInfo;
+
+// Indicates the current version of the multiHAL interface formatted as (HAL major version) << 24 |
+// (HAL minor version) << 16 | (multiHAL version)
+#define SUB_HAL_2_0_VERSION 0x02000000
+
+namespace android {
+namespace hardware {
+namespace sensors {
+namespace V2_0 {
+namespace implementation {
+
+/**
+ * Wrapper around wake lock acquisition functions (acquire/release_wake_lock) that provides a
+ * RAII-style mechanism for keeping a wake lock held for the duration of a scoped block.
+ * When a ScopedWakelock is created, it increments the reference count stored in the HalProxy
+ * for the sub-HALs specific wake lock, acquiring the wake lock if necessary. When the object goes
+ * out of scope, the ref count is decremented, potentially releasing the wake lock if no other
+ * references to the wake lock exist.
+ *
+ * This class is allocated through the createScopedWakelock callback inside the IHalProxyCallback
+ * provided to sub-HALs during initialization and should be used for all wake lock acquisition
+ * inside of the sub-HAL to ensure wake locks are not held indefinitely.
+ *
+ * The most prevalent use case for this class will be for posting events to the framework through
+ * the postEvents HalProxy callback. The expectation is that sub-HALs will create this
+ * ScopedWakelock through the createScopedWakelock upon receiving a sensor events. The lock boolean
+ * provided to createScopedWakelock will be set the according to whether the sensor events are
+ * from wakeup sensors. Then, the sub-HAL will perform any processing necessary before invoking the
+ * postEvents callback passing in the previously created ScopedWakelock. At this point, ownership
+ * of the object will be passed to the HalProxy that will then be responsible for ensuring any
+ * wake locks continue to be held, if necessary.
+ */
+class ScopedWakelock {
+ public:
+ ScopedWakelock(ScopedWakelock&&) = default;
+ ScopedWakelock& operator=(ScopedWakelock&&) = default;
+ virtual ~ScopedWakelock() { mLocked = false; };
+
+ bool isLocked() const { return mLocked; }
+
+ protected:
+ bool mLocked;
+
+ private:
+ // TODO: Mark HalProxy's subclass of ScopedWakelock as a friend so that it can be initialized.
+ ScopedWakelock();
+ ScopedWakelock(const ScopedWakelock&) = delete;
+ ScopedWakelock& operator=(const ScopedWakelock&) = delete;
+};
+
+/**
+ * Interface that contains several callbacks into the HalProxy class to communicate dynamic sensor
+ * changes and sensor events to the framework and acquire wake locks. The HalProxy will ensure
+ * callbacks occurring at the same time from multiple sub-HALs are synchronized in a safe, efficient
+ * manner.
+ */
+class IHalProxyCallback : public ISensorsCallback {
+ public:
+ /**
+ * Thread-safe callback used to post events to the HalProxy. Sub-HALs should invoke this
+ * whenever new sensor events need to be delivered to the sensors framework. Once invoked, the
+ * HalProxy will attempt to send events to the sensors framework using a blocking write with a
+ * 5 second timeout. This write may be done asynchronously if the queue used to communicate
+ * with the framework is full to avoid blocking sub-HALs for the length of the timeout. If the
+ * write fails, the events will be dropped and any wake locks held will be released.
+ *
+ * The provided ScopedWakelock must be locked if the events are from wakeup sensors. If it's
+ * not locked accordingly, the HalProxy will crash as this indicates the sub-HAL isn't compliant
+ * with the sensors HAL 2.0 specification. Additionally, since ScopedWakelock isn't copyable,
+ * the HalProxy will take ownership of the wake lock given when this method is invoked. Once the
+ * method returns, the HalProxy will handle holding the wake lock, if necessary, until the
+ * framework has successfully processed any wakeup events.
+ *
+ * No return type is used for this callback to avoid sub-HALs trying to resend events when
+ * writes fail. Writes should only fail when the framework is under inordinate stress which will
+ * likely result in a framework restart so retrying will likely only result in overloading the
+ * HalProxy. Sub-HALs should always assume that the write was a success and perform any
+ * necessary cleanup. Additionally, the HalProxy will ensure it logs any errors (through ADB and
+ * bug reports) it encounters during delivery to ensure it's obvious that a failure occurred.
+ *
+ * @param events the events that should be sent to the sensors framework
+ * @param wakelock ScopedWakelock that should be locked to send events from wake sensors and
+ * unlocked otherwise.
+ */
+ virtual void postEvents(const std::vector<Event>& events, ScopedWakelock wakelock) = 0;
+
+ /**
+ * Initializes a ScopedWakelock on the stack that, when locked, will increment the reference
+ * count for the sub-HAL's wake lock managed inside the HalProxy. See the ScopedWakelock class
+ * definition for how it should be used.
+ *
+ * @param lock whether the ScopedWakelock should be locked before it's returned.
+ * @return the created ScopedWakelock
+ */
+ virtual ScopedWakelock createScopedWakelock(bool lock) = 0;
+};
+
+/**
+ * ISensorsSubHal is an interface that sub-HALs must implement in order to be compliant with
+ * multihal 2.0 and in order for the HalProxy to successfully load and communicate with the sub-HAL.
+ *
+ * Any vendor wishing to implement this interface and support multihal 2.0 will need to create a
+ * dynamic library that exposes sensorsHalGetSubHal (defined below). This library will be loaded by
+ * the HalProxy when the sensors HAL is initialized and then the HalProxy will retrieve the vendor's
+ * implementation of sensorsHalGetSubHal.
+ *
+ * With the exception of the initialize method, ISensorsSubHal will implement the ISensors.hal spec.
+ * Any sensor handles given to the HalProxy, either through getSensorsList() or the
+ * onDynamicSensors(Dis)Connected callbacks, will be translated to avoid clashing with other sub-HAL
+ * handles. To achieve this, the HalProxy will use the upper byte to store the sub-HAL index and
+ * sub-HALs can continue to use the lower 3 bytes of the handle.
+ */
+class ISensorsSubHal : public ISensors {
+ // The ISensors version of initialize isn't used for multihal. Instead, sub-HALs must implement
+ // the version below to allow communciation logic to centralized in the HalProxy
+ Return<Result> initialize(
+ const ::android::hardware::MQDescriptorSync<Event>& /* eventQueueDescriptor */,
+ const ::android::hardware::MQDescriptorSync<uint32_t>& /* wakeLockDescriptor */,
+ const sp<ISensorsCallback>& /* sensorsCallback */) final {
+ return Result::INVALID_OPERATION;
+ }
+
+ /**
+ * Method defined in ::android::hidl::base::V1_0::IBase.
+ *
+ * This method should write debug information to hidl_handle that is useful for debugging
+ * issues. Suggestions include:
+ * - Sensor info including handle values and any other state available in the SensorInfo class
+ * - List of active sensors and their current sampling period and reporting latency
+ * - Information about pending flush requests
+ * - Current operating mode
+ * - Currently registered direct channel info
+ * - A history of any of the above
+ */
+ virtual Return<void> debug(const hidl_handle& fd, const hidl_vec<hidl_string>& args) = 0;
+
+ /**
+ * @return A human-readable name for use in wake locks and logging.
+ */
+ virtual const std::string getName() = 0;
+
+ /**
+ * First method invoked on the sub-HAL after it's allocated through sensorsHalGetSubHal() by the
+ * HalProxy. Sub-HALs should use this to initialize any state and retain the callback given in
+ * order to communicate with the HalProxy.
+ *
+ * @param halProxyCallback callback used to inform the HalProxy when a dynamic sensor's state
+ * changes, new sensor events should be sent to the framework, and when a new ScopedWakelock
+ * should be created.
+ * @return result OK on success
+ */
+ virtual Return<Result> initialize(const sp<IHalProxyCallback>& halProxyCallback) = 0;
+};
+
+} // namespace implementation
+} // namespace V2_0
+} // namespace sensors
+} // namespace hardware
+} // namespace android
+
+using ::android::hardware::sensors::V2_0::implementation::ISensorsSubHal;
+
+/**
+ * Function that must be exported so the HalProxy class can invoke it on the sub-HAL dynamic
+ * library. This function will only be invoked once at initialization time.
+ *
+ * NOTE: The supported sensors HAL version must match SUB_HAL_2_0_VERSION exactly or the HalProxy
+ * will fail to initialize.
+ *
+ * @param uint32_t when this function returns, this parameter must contain the HAL version that
+ * this sub-HAL supports. To support this version of multi-HAL, this must be set to
+ * SUB_HAL_2_0_VERSION.
+ * @return A statically allocated, valid ISensorsSubHal implementation.
+ */
+__attribute__((visibility("default"))) extern "C" ISensorsSubHal* sensorsHalGetSubHal(
+ uint32_t* version);