gem5  v21.1.0.2
Public Member Functions | Protected Types | Protected Member Functions | Protected Attributes | Static Protected Attributes | List of all members
gem5::I2CBus Class Reference

#include <bus.hh>

Inheritance diagram for gem5::I2CBus:
gem5::BasicPioDevice gem5::PioDevice gem5::ClockedObject gem5::SimObject gem5::Clocked gem5::EventManager gem5::Serializable gem5::Drainable gem5::statistics::Group gem5::Named

Public Member Functions

 I2CBus (const I2CBusParams &p)
 4KB - see e.g. More...
 
Tick read (PacketPtr pkt) override
 Reads will always be to SB_CONTROLS. More...
 
Tick write (PacketPtr pkt) override
 The default i2c bus driver used by the realview pbx board writes to this device one bit at a time. 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::BasicPioDevice
 PARAMS (BasicPioDevice)
 
 BasicPioDevice (const Params &p, Addr size)
 
AddrRangeList getAddrRanges () const override
 Determine the address ranges that this device responds to. More...
 
- Public Member Functions inherited from gem5::PioDevice
 PioDevice (const Params &p)
 
virtual ~PioDevice ()
 
void init () override
 init() is called after all C++ SimObjects have been created and all ports are connected. More...
 
PortgetPort (const std::string &if_name, PortID idx=InvalidPortID) override
 Get a port with a given name and index. More...
 
- Public Member Functions inherited from gem5::ClockedObject
 ClockedObject (const ClockedObjectParams &p)
 
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::SimObject
const Paramsparams () const
 
 SimObject (const Params &p)
 
virtual ~SimObject ()
 
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 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
 
- Public Member Functions inherited from gem5::Clocked
void updateClockPeriod ()
 Update the tick to the current tick. More...
 
Tick clockEdge (Cycles cycles=Cycles(0)) const
 Determine the tick when a cycle begins, by default the current one, but the argument also enables the caller to determine a future cycle. More...
 
Cycles curCycle () const
 Determine the current cycle, corresponding to a tick aligned to a clock edge. More...
 
Tick nextCycle () const
 Based on the clock of the object, determine the start tick of the first cycle that is at least one cycle in the future. More...
 
uint64_t frequency () const
 
Tick clockPeriod () const
 
double voltage () const
 
Cycles ticksToCycles (Tick t) const
 
Tick cyclesToTicks (Cycles c) const
 

Protected Types

enum  I2CState { IDLE, RECEIVING_ADDR, RECEIVING_DATA, SENDING_DATA }
 

Protected Member Functions

void updateSignals (PacketPtr pkt)
 Update data (sda) and clock (scl) to match any transitions specified by pkt. More...
 
bool isClockSet (PacketPtr pkt) const
 Clock set check. More...
 
bool isStart (PacketPtr pkt) const
 i2c start signal check More...
 
bool isEnd (PacketPtr pkt) const
 i2c end signal check 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...
 
- Protected Member Functions inherited from gem5::Clocked
 Clocked (ClockDomain &clk_domain)
 Create a clocked object and set the clock domain based on the parameters. More...
 
 Clocked (Clocked &)=delete
 
Clockedoperator= (Clocked &)=delete
 
virtual ~Clocked ()
 Virtual destructor due to inheritance. More...
 
void resetClock () const
 Reset the object's clock using the current global tick value. More...
 
virtual void clockPeriodUpdated ()
 A hook subclasses can implement so they can do any extra work that's needed when the clock rate is changed. More...
 

Protected Attributes

uint8_t scl
 I2C clock wire (0, 1). More...
 
uint8_t sda
 I2C data wire (0, 1) More...
 
enum I2CState state
 State used by I2CBus::write to determine what stage of an i2c transmission it is currently in. More...
 
int currBit
 Order of the bit of the current message that is being sent or received (0 - 7). More...
 
uint8_t i2cAddr
 Key used to access a device in the slave devices map. More...
 
uint8_t message
 8-bit buffer used to send and receive messages bit by bit. More...
 
std::map< uint8_t, I2CDevice * > devices
 All the slave i2c devices that are connected to this bus. More...
 
- Protected Attributes inherited from gem5::BasicPioDevice
Addr pioAddr
 Address that the device listens to. More...
 
Addr pioSize
 Size that the device's address range. More...
 
Tick pioDelay
 Delay that the device experinces on an access. More...
 
- Protected Attributes inherited from gem5::PioDevice
Systemsys
 
PioPort< PioDevicepioPort
 The pioPort that handles the requests for us and provides us requests that it sees. 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...
 

Static Protected Attributes

static const int SB_CONTROLS = 0x0
 Read [and Set] serial control bits: Bit [0] is SCL Bit [1] is SDA. More...
 
static const int SB_CONTROLC = 0x4
 Clear control bits. More...
 

Additional Inherited Members

- Public Types inherited from gem5::PioDevice
using Params = PioDeviceParams
 
- Public Types inherited from gem5::ClockedObject
using Params = ClockedObjectParams
 Parameters of ClockedObject. More...
 
- 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...
 
- Public Attributes inherited from gem5::ClockedObject
PowerStatepowerState
 

Detailed Description

Definition at line 56 of file bus.hh.

Member Enumeration Documentation

◆ I2CState

enum gem5::I2CBus::I2CState
protected
Enumerator
IDLE 
RECEIVING_ADDR 
RECEIVING_DATA 
SENDING_DATA 

Definition at line 60 of file bus.hh.

Constructor & Destructor Documentation

◆ I2CBus()

gem5::I2CBus::I2CBus ( const I2CBusParams &  p)

Member Function Documentation

◆ isClockSet()

bool gem5::I2CBus::isClockSet ( PacketPtr  pkt) const
protected

Clock set check.

Parameters
pktmemory request packet
Returns
true if pkt indicates that scl transition from 0 to 1

Definition at line 196 of file bus.cc.

References gem5::Packet::getAddr(), gem5::Packet::getRaw(), gem5::BasicPioDevice::pioAddr, and SB_CONTROLS.

Referenced by write().

◆ isEnd()

bool gem5::I2CBus::isEnd ( PacketPtr  pkt) const
protected

i2c end signal check

Parameters
pktmemory request packet
Returns
true if pkt indicates stopping the current transmission

Definition at line 212 of file bus.cc.

References gem5::Packet::getAddr(), gem5::Packet::getRaw(), gem5::BasicPioDevice::pioAddr, SB_CONTROLS, and scl.

Referenced by write().

◆ isStart()

bool gem5::I2CBus::isStart ( PacketPtr  pkt) const
protected

i2c start signal check

Parameters
pktmemory request packet
Returns
true if pkt indicates a new transmission

Definition at line 204 of file bus.cc.

References gem5::Packet::getAddr(), gem5::Packet::getRaw(), gem5::BasicPioDevice::pioAddr, SB_CONTROLC, and scl.

Referenced by write().

◆ read()

Tick gem5::I2CBus::read ( PacketPtr  pkt)
overridevirtual

Reads will always be to SB_CONTROLS.

The kernel wants to know the state of sda and scl.

Implements gem5::PioDevice.

Definition at line 74 of file bus.cc.

References gem5::Packet::getAddr(), gem5::Packet::makeAtomicResponse(), gem5::BasicPioDevice::pioAddr, gem5::BasicPioDevice::pioDelay, SB_CONTROLS, scl, sda, and gem5::Packet::setRaw().

◆ serialize()

void gem5::I2CBus::serialize ( CheckpointOut cp) const
overridevirtual

Serialize an object.

Output an object's state into the current checkpoint section.

Parameters
cpCheckpoint state

Implements gem5::Serializable.

Definition at line 219 of file bus.cc.

References currBit, DPRINTF, i2cAddr, message, scl, sda, SERIALIZE_ENUM, SERIALIZE_SCALAR, and state.

◆ unserialize()

void gem5::I2CBus::unserialize ( CheckpointIn cp)
overridevirtual

Unserialize an object.

Read an object's state from the current checkpoint section.

Parameters
cpCheckpoint state

Implements gem5::Serializable.

Definition at line 231 of file bus.cc.

References currBit, DPRINTF, i2cAddr, message, scl, sda, state, UNSERIALIZE_ENUM, and UNSERIALIZE_SCALAR.

◆ updateSignals()

void gem5::I2CBus::updateSignals ( PacketPtr  pkt)
protected

Update data (sda) and clock (scl) to match any transitions specified by pkt.

Parameters
pktmemory request packet

Definition at line 176 of file bus.cc.

References gem5::Packet::getAddr(), gem5::Packet::getRaw(), gem5::BasicPioDevice::pioAddr, SB_CONTROLC, SB_CONTROLS, scl, and sda.

Referenced by write().

◆ write()

Tick gem5::I2CBus::write ( PacketPtr  pkt)
overridevirtual

The default i2c bus driver used by the realview pbx board writes to this device one bit at a time.

To facilitate making new i2c devices, i2cBus::write takes care of the low-level details of the i2c protocol. See the I2C Specification [1] for a detailed description of the protocol.

[1] - http://www.nxp.com/documents/user_manual/UM10204.pdf

Implements gem5::PioDevice.

Definition at line 93 of file bus.cc.

References currBit, gem5::ArmISA::d, devices, gem5::Packet::getAddr(), i2cAddr, IDLE, isClockSet(), isEnd(), isStart(), message, panic, gem5::BasicPioDevice::pioAddr, gem5::BasicPioDevice::pioDelay, RECEIVING_ADDR, RECEIVING_DATA, SB_CONTROLC, SB_CONTROLS, sda, SENDING_DATA, state, and updateSignals().

Member Data Documentation

◆ currBit

int gem5::I2CBus::currBit
protected

Order of the bit of the current message that is being sent or received (0 - 7).

Definition at line 94 of file bus.hh.

Referenced by serialize(), unserialize(), and write().

◆ devices

std::map<uint8_t, I2CDevice*> gem5::I2CBus::devices
protected

All the slave i2c devices that are connected to this bus.

Each device has an address that points to the actual device.

Definition at line 111 of file bus.hh.

Referenced by I2CBus(), and write().

◆ i2cAddr

uint8_t gem5::I2CBus::i2cAddr
protected

Key used to access a device in the slave devices map.

This is the same address that is specified in kernel board initialization code (e.g., arch/arm/mach-realview/core.c).

Definition at line 101 of file bus.hh.

Referenced by serialize(), unserialize(), and write().

◆ message

uint8_t gem5::I2CBus::message
protected

8-bit buffer used to send and receive messages bit by bit.

Definition at line 104 of file bus.hh.

Referenced by serialize(), unserialize(), and write().

◆ SB_CONTROLC

const int gem5::I2CBus::SB_CONTROLC = 0x4
staticprotected

Clear control bits.

Analogous to SB_CONTROLS

Definition at line 77 of file bus.hh.

Referenced by isStart(), updateSignals(), and write().

◆ SB_CONTROLS

const int gem5::I2CBus::SB_CONTROLS = 0x0
staticprotected

Read [and Set] serial control bits: Bit [0] is SCL Bit [1] is SDA.

http://infocenter.arm.com/help/topic/com.arm.doc.dui0440b/Bbajdjeg.html

Definition at line 75 of file bus.hh.

Referenced by isClockSet(), isEnd(), read(), updateSignals(), and write().

◆ scl

uint8_t gem5::I2CBus::scl
protected

I2C clock wire (0, 1).

Definition at line 80 of file bus.hh.

Referenced by isEnd(), isStart(), read(), serialize(), unserialize(), and updateSignals().

◆ sda

uint8_t gem5::I2CBus::sda
protected

I2C data wire (0, 1)

Definition at line 82 of file bus.hh.

Referenced by read(), serialize(), unserialize(), updateSignals(), and write().

◆ state

enum I2CState gem5::I2CBus::state
protected

State used by I2CBus::write to determine what stage of an i2c transmission it is currently in.

Definition at line 88 of file bus.hh.

Referenced by serialize(), unserialize(), and write().


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

Generated on Tue Sep 21 2021 12:27:42 for gem5 by doxygen 1.8.17