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author | Andreas Sandberg <andreas.sandberg@arm.com> | 2015-12-10 10:35:18 +0000 |
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committer | Andreas Sandberg <andreas.sandberg@arm.com> | 2015-12-10 10:35:18 +0000 |
commit | ef097ac4381ad2f14acda640ae198f04d9f7988d (patch) | |
tree | f527859d2309feebc2c5947542dad529ebfc21f5 /src/dev/i2cbus.cc | |
parent | 38e2860c36997858131dc47e1152bb583f68608e (diff) | |
download | gem5-ef097ac4381ad2f14acda640ae198f04d9f7988d.tar.xz |
dev: Move i2c functionality to src/dev/i2c/
--HG--
rename : src/dev/I2C.py => src/dev/i2c/I2C.py
rename : src/dev/i2cbus.cc => src/dev/i2c/bus.cc
rename : src/dev/i2cbus.hh => src/dev/i2c/bus.hh
rename : src/dev/i2cdev.hh => src/dev/i2c/device.hh
Diffstat (limited to 'src/dev/i2cbus.cc')
-rw-r--r-- | src/dev/i2cbus.cc | 242 |
1 files changed, 0 insertions, 242 deletions
diff --git a/src/dev/i2cbus.cc b/src/dev/i2cbus.cc deleted file mode 100644 index 03ca6769c..000000000 --- a/src/dev/i2cbus.cc +++ /dev/null @@ -1,242 +0,0 @@ -/* - * 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(CheckpointOut &cp) const -{ - 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(CheckpointIn &cp) -{ - 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); -} |