diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/dev/I2C.py | 51 | ||||
| -rw-r--r-- | src/dev/SConscript | 2 | ||||
| -rw-r--r-- | src/dev/i2cbus.cc | 242 | ||||
| -rw-r--r-- | src/dev/i2cbus.hh | 153 | ||||
| -rw-r--r-- | src/dev/i2cdev.hh | 96 |
5 files changed, 544 insertions, 0 deletions
diff --git a/src/dev/I2C.py b/src/dev/I2C.py new file mode 100644 index 000000000..2ac463fbc --- /dev/null +++ b/src/dev/I2C.py @@ -0,0 +1,51 @@ +# Copyright (c) 2012 ARM Limited +# All rights reserved. +# +# The license below extends only to copyright in the software and shall +# not be construed as granting a license to any other intellectual +# property including but not limited to intellectual property relating +# to a hardware implementation of the functionality of the software +# licensed hereunder. You may use the software subject to the license +# terms below provided that you ensure that this notice is replicated +# unmodified and in its entirety in all distributions of the software, +# modified or unmodified, in source code or in binary form. +# +# Redistribution and use in source and binary forms, with or without +# modification, are permitted provided that the following conditions are +# met: redistributions of source code must retain the above copyright +# notice, this list of conditions and the following disclaimer; +# redistributions in binary form must reproduce the above copyright +# notice, this list of conditions and the following disclaimer in the +# documentation and/or other materials provided with the distribution; +# neither the name of the copyright holders nor the names of its +# contributors may be used to endorse or promote products derived from +# this software without specific prior written permission. +# +# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR +# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT +# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT +# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, +# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY +# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE +# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. +# +# Authors: Peter Enns + +from m5.SimObject import SimObject +from m5.params import * +from Device import BasicPioDevice + +class I2CDevice(SimObject): + type = 'I2CDevice' + cxx_header = "dev/i2cdev.hh" + abstract = True + i2c_addr = Param.UInt8("Address of device on i2c bus") + +class I2CBus(BasicPioDevice): + type = 'I2CBus' + cxx_header = "dev/i2cbus.hh" + devices = VectorParam.I2CDevice([], "Devices") diff --git a/src/dev/SConscript b/src/dev/SConscript index 8596c2f74..416e5052f 100644 --- a/src/dev/SConscript +++ b/src/dev/SConscript @@ -43,6 +43,7 @@ SimObject('BadDevice.py') SimObject('CopyEngine.py') SimObject('DiskImage.py') SimObject('Ethernet.py') +SimObject('I2C.py') SimObject('Ide.py') SimObject('Pci.py') SimObject('Platform.py') @@ -61,6 +62,7 @@ Source('etherint.cc') Source('etherlink.cc') Source('etherpkt.cc') Source('ethertap.cc') +Source('i2cbus.cc') Source('i8254xGBe.cc') Source('ide_ctrl.cc') Source('ide_disk.cc') diff --git a/src/dev/i2cbus.cc b/src/dev/i2cbus.cc new file mode 100644 index 000000000..9d7da44d0 --- /dev/null +++ b/src/dev/i2cbus.cc @@ -0,0 +1,242 @@ +/* + * Copyright (c) 2012 ARM Limited + * All rights reserved + * + * The license below extends only to copyright in the software and shall + * not be construed as granting a license to any other intellectual + * property including but not limited to intellectual property relating + * to a hardware implementation of the functionality of the software + * licensed hereunder. You may use the software subject to the license + * terms below provided that you ensure that this notice is replicated + * unmodified and in its entirety in all distributions of the software, + * modified or unmodified, in source code or in binary form. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are + * met: redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer; + * redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution; + * neither the name of the copyright holders nor the names of its + * contributors may be used to endorse or promote products derived from + * this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR + * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT + * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT + * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE + * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + * + * Authors: Peter Enns + */ + +#include "dev/i2cbus.hh" + +#include "debug/Checkpoint.hh" +#include "mem/packet_access.hh" + +// clang complains about std::set being overloaded with Packet::set if +// we open up the entire namespace std +using std::vector; +using std::map; + +/** + * 4KB - see e.g. + * http://infocenter.arm.com/help/topic/com.arm.doc.dui0440b/Bbajihec.html + */ +I2CBus::I2CBus(const I2CBusParams *p) + : BasicPioDevice(p, 0xfff), scl(1), sda(1), state(IDLE), currBit(7), + i2cAddr(0x00), message(0x00) +{ + vector<I2CDevice*> devs = p->devices; + + for (auto d : p->devices) { + devices[d->i2cAddr()] = d; + } +} + +/** + * Reads will always be to SB_CONTROLS. The kernel wants to know the state + * of sda and scl. + */ +Tick +I2CBus::read(PacketPtr pkt) +{ + assert(pkt->getAddr() == pioAddr + SB_CONTROLS); + + pkt->set<uint8_t>((sda << 1) | scl); + pkt->makeAtomicResponse(); + return pioDelay; +} + +/** + * 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 + */ +Tick +I2CBus::write(PacketPtr pkt) +{ + assert(pkt->getAddr() == pioAddr + SB_CONTROLS || + pkt->getAddr() == pioAddr + SB_CONTROLC); + + updateSignals(pkt); + + // Check if the bus master is starting a new transmission. + if (isStart(pkt)) { + state = RECEIVING_ADDR; + message = 0x00; + currBit = 7; + /* Most i2c devices expect something special (e.g., command, + * register address) in the first byte they receive so they + * must be notified somehow that this is a new transmission. + */ + for (auto& d : devices) { + d.second->i2cStart(); + } + return pioDelay; + } + + // Check if the bus master is ending a transmission. + if (isEnd(pkt)) { + state = IDLE; + return pioDelay; + } + + // Only change state when the clock is transitioning from low to high. + // This may not perfectly mimic physical i2c devices but the important + // part is to only do the following once per clock cycle. + if (isClockSet(pkt)) { + switch (state) { + case RECEIVING_ADDR: + if (currBit >= 0) { + message |= sda << currBit; + currBit--; + } else { + i2cAddr = message >> 1; + assert(devices.find(i2cAddr) != devices.end()); + if (message & 0x01) { + state = SENDING_DATA; + message = devices[i2cAddr]->read(); + } else { + state = RECEIVING_DATA; + message = 0x00; + } + currBit = 7; + sda = 0; /* Ack */ + } + break; + case RECEIVING_DATA: + if (currBit >= 0) { + message |= sda << currBit; + currBit--; + } else { + devices[i2cAddr]->write(message); + message = 0x00; + currBit = 7; + sda = 0; /* Ack */ + } + break; + case SENDING_DATA: + if (currBit >= 0) { + sda = (message >> currBit) & 0x01; + currBit--; + } else { + if (!sda) /* Check for ack from the bus master. */ + message = devices[i2cAddr]->read(); + currBit = 7; + } + break; + case IDLE: + default: + panic("Invalid state on posedge of clock in I2CBus::write.\n"); + break; + } + } + + return pioDelay; +} + +void +I2CBus::updateSignals(PacketPtr pkt) +{ + uint8_t msg = pkt->get<uint8_t>(); + Addr daddr = pkt->getAddr() - pioAddr; + + switch (daddr) { + case SB_CONTROLS: + scl = (msg & 1) ? 1 : scl; + sda = (msg & 2) ? 1 : sda; + break; + case SB_CONTROLC: + scl = (msg & 1) ? 0 : scl; + sda = (msg & 2) ? 0 : sda; + break; + default: + break; + } +} + +bool +I2CBus::isClockSet(PacketPtr pkt) const +{ + uint8_t msg = pkt->get<uint8_t>(); + Addr daddr = pkt->getAddr() - pioAddr; + return daddr == SB_CONTROLS && (msg & 1); +} + +bool +I2CBus::isStart(PacketPtr pkt) const +{ + uint8_t msg = pkt->get<uint8_t>(); + Addr daddr = pkt->getAddr() - pioAddr; + return scl && (msg & 2) && daddr == SB_CONTROLC; +} + +bool +I2CBus::isEnd(PacketPtr pkt) const +{ + uint8_t msg = pkt->get<uint8_t>(); + Addr daddr = pkt->getAddr() - pioAddr; + return scl && (msg & 2) && daddr == SB_CONTROLS; +} +void +I2CBus::serialize(std::ostream &os) +{ + DPRINTF(Checkpoint, "Serializing I2C bus.\n"); + SERIALIZE_SCALAR(scl); + SERIALIZE_SCALAR(sda); + SERIALIZE_ENUM(state); + SERIALIZE_SCALAR(currBit); + SERIALIZE_SCALAR(i2cAddr); + SERIALIZE_SCALAR(message); +} + +void +I2CBus::unserialize(Checkpoint *cp, const std::string §ion) +{ + DPRINTF(Checkpoint, "Unserializing I2C bus.\n"); + UNSERIALIZE_SCALAR(scl); + UNSERIALIZE_SCALAR(sda); + UNSERIALIZE_ENUM(state); + UNSERIALIZE_SCALAR(currBit); + UNSERIALIZE_SCALAR(i2cAddr); + UNSERIALIZE_SCALAR(message); +} + +I2CBus* +I2CBusParams::create() +{ + return new I2CBus(this); +} diff --git a/src/dev/i2cbus.hh b/src/dev/i2cbus.hh new file mode 100644 index 000000000..318950b39 --- /dev/null +++ b/src/dev/i2cbus.hh @@ -0,0 +1,153 @@ +/* + * Copyright (c) 2012 ARM Limited + * All rights reserved + * + * The license below extends only to copyright in the software and shall + * not be construed as granting a license to any other intellectual + * property including but not limited to intellectual property relating + * to a hardware implementation of the functionality of the software + * licensed hereunder. You may use the software subject to the license + * terms below provided that you ensure that this notice is replicated + * unmodified and in its entirety in all distributions of the software, + * modified or unmodified, in source code or in binary form. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are + * met: redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer; + * redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution; + * neither the name of the copyright holders nor the names of its + * contributors may be used to endorse or promote products derived from + * this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR + * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT + * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT + * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE + * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + * + * Authors: Peter Enns + */ + + +/** @file + * Implementiation of an i2c bus + */ + +#ifndef __DEV_I2CBUS__ +#define __DEV_I2CBUS__ + +#include <map> + +#include "dev/i2cdev.hh" +#include "dev/io_device.hh" +#include "params/I2CBus.hh" + +class I2CBus : public BasicPioDevice +{ + protected: + + enum I2CState { + IDLE, + RECEIVING_ADDR, + RECEIVING_DATA, + SENDING_DATA, + }; + + /** + * 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 + */ + static const int SB_CONTROLS = 0x0; + /** Clear control bits. Analogous to SB_CONTROLS */ + static const int SB_CONTROLC = 0x4; + + /** I2C clock wire (0, 1). */ + uint8_t scl; + /** I2C data wire (0, 1) */ + uint8_t sda; + + /** + * State used by I2CBus::write to determine what stage of an i2c + * transmission it is currently in. + */ + enum I2CState state; + + /** + * Order of the bit of the current message that is being sent or + * received (0 - 7). + */ + int currBit; + + /** + * 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). + */ + uint8_t i2cAddr; + + /** 8-bit buffer used to send and receive messages bit by bit. */ + uint8_t message; + + /** + * All the slave i2c devices that are connected to this + * bus. Each device has an address that points to the actual + * device. + */ + std::map<uint8_t, I2CDevice*> devices; + + /** + * Update data (sda) and clock (scl) to match any transitions + * specified by pkt. + * + * @param pkt memory request packet + */ + void updateSignals(PacketPtr pkt); + + /** + * Clock set check + * + * @param pkt memory request packet + * @return true if pkt indicates that scl transition from 0 to 1 + */ + bool isClockSet(PacketPtr pkt) const; + + /** + * i2c start signal check + * + * @param pkt memory request packet + * @return true if pkt indicates a new transmission + */ + bool isStart(PacketPtr pkt) const; + + /** + * i2c end signal check + * + * @param pkt memory request packet + * @return true if pkt indicates stopping the current transmission + */ + bool isEnd(PacketPtr pkt) const; + + public: + + I2CBus(const I2CBusParams* p); + + virtual Tick read(PacketPtr pkt); + virtual Tick write(PacketPtr pkt); + + virtual void serialize(std::ostream& os); + virtual void unserialize(Checkpoint* cp, const std::string& section); +}; + +#endif //__DEV_I2CBUS diff --git a/src/dev/i2cdev.hh b/src/dev/i2cdev.hh new file mode 100644 index 000000000..d101483fd --- /dev/null +++ b/src/dev/i2cdev.hh @@ -0,0 +1,96 @@ +/* + * Copyright (c) 2012 ARM Limited + * All rights reserved + * + * The license below extends only to copyright in the software and shall + * not be construed as granting a license to any other intellectual + * property including but not limited to intellectual property relating + * to a hardware implementation of the functionality of the software + * licensed hereunder. You may use the software subject to the license + * terms below provided that you ensure that this notice is replicated + * unmodified and in its entirety in all distributions of the software, + * modified or unmodified, in source code or in binary form. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are + * met: redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer; + * redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution; + * neither the name of the copyright holders nor the names of its + * contributors may be used to endorse or promote products derived from + * this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR + * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT + * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT + * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE + * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.* + * + * Authors: Peter Enns + */ + + +/** @file + * All i2c devices should derive from this class. + */ + +#ifndef __DEV_I2CDEV__ +#define __DEV_I2CDEV__ + +#include "base/types.hh" +#include "params/I2CDevice.hh" +#include "sim/sim_object.hh" + +class I2CDevice : public SimObject +{ + + protected: + + uint8_t _addr; + + public: + + I2CDevice(const I2CDeviceParams* p) + : SimObject(p), _addr(p->i2c_addr) + { } + + virtual ~I2CDevice() { } + + /** + * Return the next message that the device expects to send. This + * will likely have side effects (e.g., incrementing a register + * pointer). + * + * @return 8-bit message the device has been set up to send + */ + virtual uint8_t read() = 0; + + /** + * Perform any actions triggered by an i2c write (save msg in a + * register, perform an interrupt, update a register pointer or + * command register, etc...) + * + * @param msg 8-bit message from master + */ + virtual void write(uint8_t msg) = 0; + + /** + * Perform any initialization necessary for the device when it + * received a start signal from the bus master (devices frequently + * expect the first write to be a register address) + */ + virtual void i2cStart() = 0; + + uint8_t i2cAddr() const { return _addr; } + +}; + +#endif // __DEV_I2CDEV__ |