gem5  v21.1.0.2
Public Member Functions | Protected Member Functions | Private Attributes | List of all members
gem5::SerialDevice Class Referenceabstract

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

#include <serial.hh>

Inheritance diagram for gem5::SerialDevice:
gem5::SimObject gem5::EventManager gem5::Serializable gem5::Drainable gem5::statistics::Group gem5::Named gem5::SerialNullDevice gem5::Terminal

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. More...
 
virtual bool dataAvailable () const =0
 Check if there is pending data from the serial device. More...
 
virtual void writeData (uint8_t c)=0
 Transmit a character from the host interface to the device. More...
 
virtual uint8_t readData ()=0
 Read a character from the device. More...
 
- Public Member Functions inherited from gem5::SimObject
const Paramsparams () 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. More...
 
virtual void loadState (CheckpointIn &cp)
 loadState() is called on each SimObject when restoring from a checkpoint. More...
 
virtual void initState ()
 initState() is called on each SimObject when not restoring from a checkpoint. More...
 
virtual void regProbePoints ()
 Register probe points for this object. More...
 
virtual void regProbeListeners ()
 Register probe listeners for this object. More...
 
ProbeManagergetProbeManager ()
 Get the probe manager for this object. More...
 
virtual PortgetPort (const std::string &if_name, PortID idx=InvalidPortID)
 Get a port with a given name and index. More...
 
virtual void startup ()
 startup() is the final initialization call before simulation. More...
 
DrainState drain () override
 Provide a default implementation of the drain interface for objects that don't need draining. More...
 
virtual void memWriteback ()
 Write back dirty buffers to memory using functional writes. More...
 
virtual void memInvalidate ()
 Invalidate the contents of memory buffers. More...
 
void serialize (CheckpointOut &cp) const override
 Serialize an object. More...
 
void unserialize (CheckpointIn &cp) override
 Unserialize an object. More...
 
- Public Member Functions inherited from gem5::EventManager
EventQueueeventQueue () 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. More...
 
void setCurTick (Tick newVal)
 
 EventManager (EventManager &em)
 Event manger manages events in the event queue. More...
 
 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. More...
 
void serializeSection (CheckpointOut &cp, const std::string &name) const
 
void unserializeSection (CheckpointIn &cp, const char *name)
 Unserialize an a child object. More...
 
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. More...
 
virtual void notifyFork ()
 Notify a child process of a fork. More...
 
- Public Member Functions inherited from gem5::statistics::Group
 Group (Group *parent, const char *name=nullptr)
 Construct a new statistics group. More...
 
virtual ~Group ()
 
virtual void regStats ()
 Callback to set stat parameters. More...
 
virtual void resetStats ()
 Callback to reset stats. More...
 
virtual void preDumpStats ()
 Callback before stats are dumped. More...
 
void addStat (statistics::Info *info)
 Register a stat with this group. More...
 
const std::map< std::string, Group * > & getStatGroups () const
 Get all child groups associated with this object. More...
 
const std::vector< Info * > & getStats () const
 Get all stats associated with this object. More...
 
void addStatGroup (const char *name, Group *block)
 Add a stat block as a child of this block. More...
 
const InforesolveStat (std::string name) const
 Resolve a stat by its name within this group. More...
 
void mergeStatGroup (Group *block)
 Merge the contents (stats & children) of a block to this block. More...
 
 Group ()=delete
 
 Group (const Group &)=delete
 
Groupoperator= (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. More...
 
- Protected Member Functions inherited from gem5::Drainable
 Drainable ()
 
virtual ~Drainable ()
 
virtual void drainResume ()
 Resume execution after a successful drain. More...
 
void signalDrainDone () const
 Signal that an object is drained. More...
 

Private Attributes

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

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. More...
 
static SimObjectfind (const char *name)
 Find the SimObject with the given name and return a pointer to it. More...
 
static void setSimObjectResolver (SimObjectResolver *resolver)
 There is a single object name resolver, and it is only set when simulation is restoring from checkpoints. More...
 
static SimObjectResolvergetSimObjectResolver ()
 There is a single object name resolver, and it is only set when simulation is restoring from checkpoints. More...
 
- Static Public Member Functions inherited from gem5::Serializable
static const std::string & currentSection ()
 Gets the fully-qualified name of the active section. More...
 
static void generateCheckpointOut (const std::string &cpt_dir, std::ofstream &outstream)
 Generate a checkpoint file so that the serialization can be routed to it. More...
 
- Protected Attributes inherited from gem5::SimObject
const SimObjectParams & _params
 Cached copy of the object parameters. More...
 
- Protected Attributes inherited from gem5::EventManager
EventQueueeventq
 A pointer to this object's event queue. More...
 

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 notifyInterface(), gem5::SimpleUart::read(), gem5::Pl011::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::SimpleUart::read(), gem5::Pl011::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
cCallback from interface layer.

Definition at line 56 of file serial.cc.

References fatal_if, and interfaceCallback.

Referenced by 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
cReceived data.

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

Referenced by gem5::SimpleUart::write(), gem5::Pl011::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:

Generated on Tue Sep 21 2021 12:28:08 for gem5 by doxygen 1.8.17