pw_chre

Oveview

Android Context Hub Runtime Environment backend. Main docs: https://pigweed.dev/pw_chre.

Classes
struct	pw::chre::NanoappMessage
struct	pw::chre::MessageToAp

Typedefs
using	pw::chre::MessageToApContext = const void *

Functions
void	pw::chre::Init ()
void	pw::chre::Deinit ()
void	pw::chre::RunEventLoop ()
void	pw::chre::StopEventLoop ()
void	pw::chre::SendMessageToNanoapp (NanoappMessage message)
void	pw::chre::FreeMessageToAp (MessageToApContext context)
void	pw::chre::SetEstimatedHostTimeOffset (int64_t offset)
bool	pw::chre::SendMessageToAp (MessageToAp message)

Variables
uint64_t	pw::chre::NanoappMessage::nano_app_id
	The id of the nanoapp this message is sent to.
uint32_t	pw::chre::NanoappMessage::message_type
	The type of message this is.
uint16_t	pw::chre::NanoappMessage::host_endpoint
	The id of the host on the AP that sent this request.
const uint8_t *	pw::chre::NanoappMessage::data
	The actual message data.
size_t	pw::chre::NanoappMessage::length
	The size in bytes of the message data.
uint64_t	pw::chre::MessageToAp::nanoapp_id
	The id of the nanoapp sending the message.
uint32_t	pw::chre::MessageToAp::message_type
	The type of the message.
uint32_t	pw::chre::MessageToAp::app_permissions
uint32_t	pw::chre::MessageToAp::message_permissions
uint16_t	pw::chre::MessageToAp::host_endpoint
	The id of the client that this message should be delivered to on the host.
bool	pw::chre::MessageToAp::woke_host
const uint8_t *	pw::chre::MessageToAp::data
size_t	pw::chre::MessageToAp::length
	The length of data in bytes.
MessageToApContext	pw::chre::MessageToAp::chre_context

Typedef Documentation

MessageToApContext

using pw::chre::MessageToApContext = typedef const void*

This is a token representing a message that CHRE allocated. It must be passed to FreeMessageToAp when the message is finished.

Function Documentation

Deinit()

void pw::chre::Deinit

(

)

Teardown the CHRE environment. This must be called after Init and after the event loop has been stopped.

FreeMessageToAp()

void pw::chre::FreeMessageToAp

(

MessageToApContext

context

)

Free a message that CHRE created to send to the AP (via SendMessageToAp). This function must be called after the message is finishd being used. After this function is called, the message data must not be accessed. This can be called from any thread.

Parameters

[in]

context

The message being freed.

Init()

void pw::chre::Init

(

)

Initialize the CHRE environment and load any static nanoapps that exist. This must be called before the event loop has been started.

RunEventLoop()

void pw::chre::RunEventLoop

(

)

Run the CHRE event loop. This function will not return until StopEventLoop is called.

SendMessageToAp()

bool pw::chre::SendMessageToAp

(

MessageToAp

message

)

CHRE calls this method to send a message to the Application Processor (AP). The client must implement this method, and the client is responsible for calling FreeMessageToAp once they are finished with the message.

Parameters

[in]	message	The message to be sent.
[out]	bool	Whether this method was successful.

SendMessageToNanoapp()

void pw::chre::SendMessageToNanoapp

(

NanoappMessage

message

)

Send a message to a nano app. This can be called from any thread.

Parameters

[in]

message

The message being send to the nano app.

SetEstimatedHostTimeOffset()

void pw::chre::SetEstimatedHostTimeOffset

(

int64_t

offset

)

Set the estimated offset between the AP time and CHRE's time.

Parameters

[in]

offset

The offset time in nanoseconds.

StopEventLoop()

void pw::chre::StopEventLoop

(

)

Stop the CHRE event loop. This can be called from any thread.

Variable Documentation

chre_context

MessageToApContext pw::chre::MessageToAp::chre_context

The context of the message, used to free the message when the client is finished sending it.

data

const uint8_t* pw::chre::MessageToAp::data

The underlying data of the message. This is owned by chre_context and should not be accessed after the message has been freed.

woke_host

bool pw::chre::MessageToAp::woke_host

Whether CHRE is responsible for waking the AP. If this is true, then the client must wake the AP in SendMessageToAp before sending this message.