76cd4393c0
Objects that are can be serialized are supposed to inherit from the
Serializable class. This class is meant to provide a unified API for
such objects. However, so far it has mainly been used by SimObjects
due to some fundamental design limitations. This changeset redesigns
to the serialization interface to make it more generic and hide the
underlying checkpoint storage. Specifically:
* Add a set of APIs to serialize into a subsection of the current
object. Previously, objects that needed this functionality would
use ad-hoc solutions using nameOut() and section name
generation. In the new world, an object that implements the
interface has the methods serializeSection() and
unserializeSection() that serialize into a named /subsection/ of
the current object. Calling serialize() serializes an object into
the current section.
* Move the name() method from Serializable to SimObject as it is no
longer needed for serialization. The fully qualified section name
is generated by the main serialization code on the fly as objects
serialize sub-objects.
* Add a scoped ScopedCheckpointSection helper class. Some objects
need to serialize data structures, that are not deriving from
Serializable, into subsections. Previously, this was done using
nameOut() and manual section name generation. To simplify this,
this changeset introduces a ScopedCheckpointSection() helper
class. When this class is instantiated, it adds a new /subsection/
and subsequent serialization calls during the lifetime of this
helper class happen inside this section (or a subsection in case
of nested sections).
* The serialize() call is now const which prevents accidental state
manipulation during serialization. Objects that rely on modifying
state can use the serializeOld() call instead. The default
implementation simply calls serialize(). Note: The old-style calls
need to be explicitly called using the
serializeOld()/serializeSectionOld() style APIs. These are used by
default when serializing SimObjects.
* Both the input and output checkpoints now use their own named
types. This hides underlying checkpoint implementation from
objects that need checkpointing and makes it easier to change the
underlying checkpoint storage code.
153 lines
4.7 KiB
C++
153 lines
4.7 KiB
C++
/*
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* Copyright (c) 2012 ARM Limited
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* All rights reserved
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*
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* The license below extends only to copyright in the software and shall
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* not be construed as granting a license to any other intellectual
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* property including but not limited to intellectual property relating
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* to a hardware implementation of the functionality of the software
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* licensed hereunder. You may use the software subject to the license
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* terms below provided that you ensure that this notice is replicated
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* unmodified and in its entirety in all distributions of the software,
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* modified or unmodified, in source code or in binary form.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are
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* met: redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer;
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* redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution;
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* neither the name of the copyright holders nor the names of its
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* contributors may be used to endorse or promote products derived from
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* this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* Authors: Peter Enns
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*/
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/** @file
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* Implementiation of an i2c bus
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*/
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#ifndef __DEV_I2CBUS__
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#define __DEV_I2CBUS__
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#include <map>
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#include "dev/i2cdev.hh"
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#include "dev/io_device.hh"
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#include "params/I2CBus.hh"
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class I2CBus : public BasicPioDevice
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{
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protected:
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enum I2CState {
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IDLE,
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RECEIVING_ADDR,
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RECEIVING_DATA,
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SENDING_DATA,
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};
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/**
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* Read [and Set] serial control bits:
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* Bit [0] is SCL
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* Bit [1] is SDA
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*
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* http://infocenter.arm.com/help/topic/com.arm.doc.dui0440b/Bbajdjeg.html
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*/
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static const int SB_CONTROLS = 0x0;
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/** Clear control bits. Analogous to SB_CONTROLS */
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static const int SB_CONTROLC = 0x4;
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/** I2C clock wire (0, 1). */
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uint8_t scl;
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/** I2C data wire (0, 1) */
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uint8_t sda;
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/**
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* State used by I2CBus::write to determine what stage of an i2c
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* transmission it is currently in.
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*/
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enum I2CState state;
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/**
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* Order of the bit of the current message that is being sent or
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* received (0 - 7).
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*/
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int currBit;
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/**
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* Key used to access a device in the slave devices map. This
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* is the same address that is specified in kernel board
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* initialization code (e.g., arch/arm/mach-realview/core.c).
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*/
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uint8_t i2cAddr;
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/** 8-bit buffer used to send and receive messages bit by bit. */
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uint8_t message;
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/**
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* All the slave i2c devices that are connected to this
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* bus. Each device has an address that points to the actual
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* device.
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*/
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std::map<uint8_t, I2CDevice*> devices;
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/**
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* Update data (sda) and clock (scl) to match any transitions
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* specified by pkt.
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*
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* @param pkt memory request packet
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*/
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void updateSignals(PacketPtr pkt);
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/**
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* Clock set check
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*
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* @param pkt memory request packet
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* @return true if pkt indicates that scl transition from 0 to 1
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*/
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bool isClockSet(PacketPtr pkt) const;
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/**
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* i2c start signal check
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*
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* @param pkt memory request packet
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* @return true if pkt indicates a new transmission
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*/
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bool isStart(PacketPtr pkt) const;
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/**
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* i2c end signal check
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*
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* @param pkt memory request packet
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* @return true if pkt indicates stopping the current transmission
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*/
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bool isEnd(PacketPtr pkt) const;
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public:
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I2CBus(const I2CBusParams* p);
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virtual Tick read(PacketPtr pkt);
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virtual Tick write(PacketPtr pkt);
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void serialize(CheckpointOut &cp) const M5_ATTR_OVERRIDE;
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void unserialize(CheckpointIn &cp) M5_ATTR_OVERRIDE;
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};
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#endif //__DEV_I2CBUS
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