gem5::SerialDevice Class Reference

Base class for serial devices such as terminals. More...

#include <serial.hh>

Inheritance diagram for gem5::SerialDevice:

Public Member Functions
	SerialDevice (const SerialDeviceParams &p)
	~SerialDevice ()
void	regInterfaceCallback (const std::function< void()> &callback)
	Register a data available callback into the host interface layer.
virtual bool	dataAvailable () const =0
	Check if there is pending data from the serial device.
virtual void	writeData (uint8_t c)=0
	Transmit a character from the host interface to the device.
virtual uint8_t	readData ()=0
	Read a character from the device.
Public Member Functions inherited from gem5::SimObject
const Params &	params () const
	SimObject (const Params &p)
virtual	~SimObject ()
virtual void	init ()
	init() is called after all C++ SimObjects have been created and all ports are connected.
virtual void	loadState (CheckpointIn &cp)
	loadState() is called on each SimObject when restoring from a checkpoint.
virtual void	initState ()
	initState() is called on each SimObject when not restoring from a checkpoint.
virtual void	regProbePoints ()
	Register probe points for this object.
virtual void	regProbeListeners ()
	Register probe listeners for this object.
ProbeManager *	getProbeManager ()
	Get the probe manager for this object.
virtual Port &	getPort (const std::string &if_name, PortID idx=InvalidPortID)
	Get a port with a given name and index.
virtual void	startup ()
	startup() is the final initialization call before simulation.
DrainState	drain () override
	Provide a default implementation of the drain interface for objects that don't need draining.
virtual void	memWriteback ()
	Write back dirty buffers to memory using functional writes.
virtual void	memInvalidate ()
	Invalidate the contents of memory buffers.
void	serialize (CheckpointOut &cp) const override
	Serialize an object.
void	unserialize (CheckpointIn &cp) override
	Unserialize an object.
Public Member Functions inherited from gem5::EventManager
EventQueue *	eventQueue () const
void	schedule (Event &event, Tick when)
void	deschedule (Event &event)
void	reschedule (Event &event, Tick when, bool always=false)
void	schedule (Event *event, Tick when)
void	deschedule (Event *event)
void	reschedule (Event *event, Tick when, bool always=false)
void	wakeupEventQueue (Tick when=(Tick) -1)
	This function is not needed by the usual gem5 event loop but may be necessary in derived EventQueues which host gem5 on other schedulers.
void	setCurTick (Tick newVal)
	EventManager (EventManager &em)
	Event manger manages events in the event queue.
	EventManager (EventManager *em)
	EventManager (EventQueue *eq)
Public Member Functions inherited from gem5::Serializable
	Serializable ()
virtual	~Serializable ()
void	serializeSection (CheckpointOut &cp, const char *name) const
	Serialize an object into a new section.
void	serializeSection (CheckpointOut &cp, const std::string &name) const
void	unserializeSection (CheckpointIn &cp, const char *name)
	Unserialize an a child object.
void	unserializeSection (CheckpointIn &cp, const std::string &name)
Public Member Functions inherited from gem5::Drainable
DrainState	drainState () const
	Return the current drain state of an object.
virtual void	notifyFork ()
	Notify a child process of a fork.
Public Member Functions inherited from gem5::statistics::Group
	Group (Group *parent, const char *name=nullptr)
	Construct a new statistics group.
virtual	~Group ()
virtual void	regStats ()
	Callback to set stat parameters.
virtual void	resetStats ()
	Callback to reset stats.
virtual void	preDumpStats ()
	Callback before stats are dumped.
void	addStat (statistics::Info *info)
	Register a stat with this group.
const std::map< std::string, Group * > &	getStatGroups () const
	Get all child groups associated with this object.
const std::vector< Info * > &	getStats () const
	Get all stats associated with this object.
void	addStatGroup (const char *name, Group *block)
	Add a stat block as a child of this block.
const Info *	resolveStat (std::string name) const
	Resolve a stat by its name within this group.
void	mergeStatGroup (Group *block)
	Merge the contents (stats & children) of a block to this block.
	Group ()=delete
	Group (const Group &)=delete
Group &	operator= (const Group &)=delete
Public Member Functions inherited from gem5::Named
	Named (const std::string &name_)
virtual	~Named ()=default
virtual std::string	name () const

Protected Member Functions
void	notifyInterface ()
	Notify the host interface of pending data.
Protected Member Functions inherited from gem5::Drainable
	Drainable ()
virtual	~Drainable ()
virtual void	drainResume ()
	Resume execution after a successful drain.
void	signalDrainDone () const
	Signal that an object is drained.

Private Attributes
std::function< void()>	interfaceCallback
	Currently regisxtered host interface layer callback.

Additional Inherited Members
Public Types inherited from gem5::SimObject
typedef SimObjectParams	Params
Static Public Member Functions inherited from gem5::SimObject
static void	serializeAll (const std::string &cpt_dir)
	Create a checkpoint by serializing all SimObjects in the system.
static SimObject *	find (const char *name)
	Find the SimObject with the given name and return a pointer to it.
static void	setSimObjectResolver (SimObjectResolver *resolver)
	There is a single object name resolver, and it is only set when simulation is restoring from checkpoints.
static SimObjectResolver *	getSimObjectResolver ()
	There is a single object name resolver, and it is only set when simulation is restoring from checkpoints.
Static Public Member Functions inherited from gem5::Serializable
static const std::string &	currentSection ()
	Gets the fully-qualified name of the active section.
static void	generateCheckpointOut (const std::string &cpt_dir, std::ofstream &outstream)
	Generate a checkpoint file so that the serialization can be routed to it.
Protected Attributes inherited from gem5::SimObject
const SimObjectParams &	_params
	Cached copy of the object parameters.
Protected Attributes inherited from gem5::EventManager
EventQueue *	eventq
	A pointer to this object's event queue.

Detailed Description

Base class for serial devices such as terminals.

This class provides a unified interface that all serial (RS232 or similar) devices must implement. A device can be wired to exactly one host serial interface (serial port model).

SerialDevices are passive devices that are driven by the serial interface using the writeData(c) (the interface sends a character) and readData() (the interface reads a character) methods. Serial devices need to override these methods to communicate with the host interface layer.

To implement basic flow control, serial devices must implement the dataAvailable() method. This method returns true if a valid character can be read using the readData() method. When data becomes available, the serial device must call the notifyInterface() method to send a callback to the interface layer.

To send a character (host to device), the interface layer calls writeData(char) to send a character to the serial device.

To read a character (device to host), the interface layer calls dataAvailable() to determine if there is a character pending. If there is data available, it immediately calls readData() to get the character. The receive loop in the serial device typically looks like this:

while (device.dataAvailable()) {
   printf("%c", (int)device.readData());
}

To avoid polling, the interface layer may register a data available callback using the regInterfaceCallback() method. The device uses this callback to notify the interface layer whenever there is new data pending. Note that devices will normally only notify the interface layer when there is a state transition in the device. E.g., the dataAvailable() transitions from false to true. This means that there can be multiple pending characters when the interface layer receives the callback.

Definition at line 94 of file serial.hh.

Constructor & Destructor Documentation

SerialDevice()

gem5::SerialDevice::SerialDevice

(

const SerialDeviceParams &

p

)

Definition at line 47 of file serial.cc.

~SerialDevice()

gem5::SerialDevice::~SerialDevice

(

)

Definition at line 51 of file serial.cc.

Member Function Documentation

dataAvailable()

virtual bool gem5::SerialDevice::dataAvailable ( ) const

pure virtual

Check if there is pending data from the serial device.

Returns

true if there is data pending that can be read using the readData() method.

Implemented in gem5::SerialNullDevice, and gem5::Terminal.

Referenced by gem5::LupioTTY::dataAvailable(), notifyInterface(), gem5::Pl011::read(), gem5::SimpleUart::read(), gem5::Uart8250::readRbr(), gem5::VirtIOConsole::TermRecvQueue::trySend(), gem5::Pl011::write(), and gem5::Uart8250::writeIer().

notifyInterface()

void gem5::SerialDevice::notifyInterface ( )

protected

Notify the host interface of pending data.

Definition at line 67 of file serial.cc.

References dataAvailable(), and interfaceCallback.

Referenced by gem5::Terminal::data().

readData()

virtual uint8_t gem5::SerialDevice::readData ( )

pure virtual

Read a character from the device.

Returns

Character from the device's output buffer, undefined if no data is pending.

Implemented in gem5::SerialNullDevice, and gem5::Terminal.

Referenced by gem5::LupioTTY::dataAvailable(), gem5::Pl011::read(), gem5::SimpleUart::read(), gem5::Uart8250::readRbr(), and gem5::VirtIOConsole::TermRecvQueue::trySend().

regInterfaceCallback()

void gem5::SerialDevice::regInterfaceCallback

(

const std::function< void()> &

callback

)

Register a data available callback into the host interface layer.

Serial devices need to call the underlying host interface layer to inform it of state change such as pending data that can be read from the device by the interface layer using the readData() method. The interface layer may use this method to register a callback that informs it of pending data.

Parameters

c	Callback from interface layer.

Definition at line 56 of file serial.cc.

References fatal_if, and interfaceCallback.

Referenced by gem5::LupioTTY::LupioTTY(), gem5::Uart::Uart(), and gem5::VirtIOConsole::VirtIOConsole().

writeData()

virtual void gem5::SerialDevice::writeData ( uint8_t c )

pure virtual

Transmit a character from the host interface to the device.

Parameters

c	Received data.

Implemented in gem5::SerialNullDevice, and gem5::Terminal.

Referenced by gem5::LupioTTY::lupioTTYWrite(), gem5::Pl011::write(), gem5::SimpleUart::write(), and gem5::Uart8250::writeThr().

Member Data Documentation

interfaceCallback

std::function<void()> gem5::SerialDevice::interfaceCallback

private

Currently regisxtered host interface layer callback.

Definition at line 143 of file serial.hh.

Referenced by notifyInterface(), and regInterfaceCallback().

---

The documentation for this class was generated from the following files:

• dev/serial/serial.hh
• dev/serial/serial.cc