blob: 220072366c97dd9ef6fdd94c5ae879027214e2dd [file] [log] [blame]
* Copyright (C) 2014 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
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* See the License for the specific language governing permissions and
* limitations under the License.
* Activity Recognition HAL. The goal is to provide low power, low latency, always-on activity
* recognition implemented in hardware (i.e. these activity recognition algorithms/classifers
* should NOT be run on the AP). By low power we mean that this may be activated 24/7 without
* impacting the battery drain speed (goal in order of 1mW including the power for sensors).
* This HAL does not specify the input sources that are used towards detecting these activities.
* It has one monitor interface which can be used to batch activities for always-on
* activity_recognition and if the latency is zero, the same interface can be used for low latency
* detection.
#include <hardware/hardware.h>
#define ACTIVITY_RECOGNITION_HARDWARE_MODULE_ID "activity_recognition"
#define ACTIVITY_RECOGNITION_HARDWARE_INTERFACE "activity_recognition_hw_if"
* Define types for various activities. Multiple activities may be active at the same time and
* sometimes none of these activities may be active.
* Each activity has a corresponding type. Only activities that are defined here should use
* android.activity_recognition.* prefix. OEM defined activities should not use this prefix.
* Activity type of OEM-defined activities should start with the reverse domain name of the entity
* defining the activity.
* When android introduces a new activity type that can potentially replace an OEM-defined activity
* type, the OEM must use the official activity type on versions of the HAL that support this new
* official activity type.
* Example (made up): Suppose Google's Glass team wants to detect nodding activity.
* - Such an activity is not officially supported in android L
* - Glass devices launching on L can implement a custom activity with
* type = ""
* - In M android release, if android decides to define ACITIVITY_TYPE_NODDING, those types
* should replace the Glass-team-specific types in all future launches.
* - When launching glass on the M release, Google should now use the official activity type
* - This way, other applications can use this activity.
#define ACTIVITY_TYPE_IN_VEHICLE "android.activity_recognition.in_vehicle"
#define ACTIVITY_TYPE_ON_BICYCLE "android.activity_recognition.on_bicycle"
#define ACTIVITY_TYPE_WALKING "android.activity_recognition.walking"
#define ACTIVITY_TYPE_RUNNING "android.activity_recognition.running"
#define ACTIVITY_TYPE_STILL "android.activity_recognition.still"
#define ACTIVITY_TYPE_TILTING "android.activity_recognition.tilting"
/* Values for activity_event.event_types. */
enum {
* A flush_complete event which indicates that a flush() has been successfully completed. This
* does not correspond to any activity/event. An event of this type should be added to the end
* of a batch FIFO and it indicates that all the events in the batch FIFO have been successfully
* reported to the framework. An event of this type should be generated only if flush() has been
* explicitly called and if the FIFO is empty at the time flush() is called it should trivially
* return a flush_complete_event to indicate that the FIFO is empty.
* A flush complete event should have the following parameters set.
* activity_event_t.event_type = ACTIVITY_EVENT_FLUSH_COMPLETE
* activity_event_t.activity = 0
* activity_event_t.timestamp = 0
* activity_event_t.reserved = 0
* See (*flush)() for more details.
/* Signifies entering an activity. */
/* Signifies exiting an activity. */
* Each event is a separate activity with event_type indicating whether this activity has started
* or ended. Eg event: (event_type="enter", activity="ON_FOOT", timestamp)
typedef struct activity_event {
/* One of the ACTIVITY_EVENT_* constants defined above. */
uint32_t event_type;
* Index of the activity in the list returned by get_supported_activities_list. If this event
* is a flush complete event, this should be set to zero.
uint32_t activity;
/* Time at which the transition/event has occurred in nanoseconds using elapsedRealTimeNano. */
int64_t timestamp;
/* Set to zero. */
int32_t reserved[4];
} activity_event_t;
typedef struct activity_recognition_module {
* Common methods of the activity recognition module. This *must* be the first member of
* activity_recognition_module as users of this structure will cast a hw_module_t to
* activity_recognition_module pointer in contexts where it's known the hw_module_t
* references an activity_recognition_module.
hw_module_t common;
* List of all activities supported by this module including OEM defined activities. Each
* activity is represented using a string defined above. Each string should be null terminated.
* The index of the activity in this array is used as a "handle" for enabling/disabling and
* event delivery.
* Return value is the size of this list.
int (*get_supported_activities_list)(struct activity_recognition_module* module,
char const* const* *activity_list);
} activity_recognition_module_t;
struct activity_recognition_device;
typedef struct activity_recognition_callback_procs {
// Callback for activity_data. This is guaranteed to not invoke any HAL methods.
// Memory allocated for the events can be reused after this method returns.
// events - Array of activity_event_t s that are reported.
// count - size of the array.
void (*activity_callback)(const struct activity_recognition_callback_procs* procs,
const activity_event_t* events, int count);
} activity_recognition_callback_procs_t;
typedef struct activity_recognition_device {
* Common methods of the activity recognition device. This *must* be the first member of
* activity_recognition_device as users of this structure will cast a hw_device_t to
* activity_recognition_device pointer in contexts where it's known the hw_device_t
* references an activity_recognition_device.
hw_device_t common;
* Sets the callback to invoke when there are events to report. This call overwrites the
* previously registered callback (if any).
void (*register_activity_callback)(const struct activity_recognition_device* dev,
const activity_recognition_callback_procs_t* callback);
* Activates monitoring of activity transitions. Activities need not be reported as soon as they
* are detected. The detected activities are stored in a FIFO and reported in batches when the
* "max_batch_report_latency" expires or when the batch FIFO is full. The implementation should
* allow the AP to go into suspend mode while the activities are detected and stored in the
* batch FIFO. Whenever events need to be reported (like when the FIFO is full or when the
* max_batch_report_latency has expired for an activity, event pair), it should wake_up the AP
* so that no events are lost. Activities are stored as transitions and they are allowed to
* overlap with each other. Each (activity, event_type) pair can be activated or deactivated
* independently of the other. The HAL implementation needs to keep track of which pairs are
* currently active and needs to detect only those pairs.
* At the first detection after this function gets called, the hardware should know whether the
* user is in the activity.
* - If event_type is ACTIVITY_EVENT_ENTER and the user is in the activity, then an
* (ACTIVITY_EVENT_ENTER, activity) event should be added to the FIFO.
* - If event_type is ACTIVITY_EVENT_EXIT and the user is not in the activity, then an
* (ACTIVITY_EVENT_EXIT, activity) event should be added to the FIFO.
* For example, suppose get_supported_activities_list contains on_bicyle and running, and the
* user is biking. Consider the following four calls that could happen in any order.
* - When enable_activity_event(on_bicycle, ACTIVITY_EVENT_ENTER) is called,
* (ACTIVITY_EVENT_ENTER, on_bicycle) should be added to the FIFO.
* - When enable_activity_event(on_bicycle, ACTIVITY_EVENT_EXIT) is called, nothing should be
* added to the FIFO.
* - When enable_activity_event(running, ACTIVITY_EVENT_ENTER) is called, nothing should be
* added to the FIFO.
* - When enable_activity_event(running, ACTIVITY_EVENT_EXIT) is called,
* (ACTIVITY_EVENT_EXIT, running) should be added to the FIFO.
* activity_handle - Index of the specific activity that needs to be detected in the list
* returned by get_supported_activities_list.
* event_type - Specific transition of the activity that needs to be detected. It should be
* max_batch_report_latency_ns - a transition can be delayed by at most
* “max_batch_report_latency” nanoseconds.
* Return 0 on success, negative errno code otherwise.
int (*enable_activity_event)(const struct activity_recognition_device* dev,
uint32_t activity_handle, uint32_t event_type, int64_t max_batch_report_latency_ns);
* Disables detection of a specific (activity, event_type) pair. All the (activity, event_type)
* events in the FIFO are discarded.
int (*disable_activity_event)(const struct activity_recognition_device* dev,
uint32_t activity_handle, uint32_t event_type);
* Flush all the batch FIFOs. Report all the activities that were stored in the FIFO so far as
* if max_batch_report_latency had expired. This shouldn't change the latency in any way. Add
* a flush_complete_event to indicate the end of the FIFO after all events are delivered.
* activity_callback should be called before this function returns successfully.
* Return 0 on success, negative errno code otherwise.
int (*flush)(const struct activity_recognition_device* dev);
// Must be set to NULL.
void (*reserved_procs[16 - 4])(void);
} activity_recognition_device_t;
static inline int activity_recognition_open(const hw_module_t* module,
activity_recognition_device_t** device) {
return module->methods->open(module,
static inline int activity_recognition_close(activity_recognition_device_t* device) {
return device->common.close(&device->common);