clock_domain.hh revision 10000:99bd071911cf
1/* 2 * Copyright (c) 2013 ARM Limited 3 * Copyright (c) 2013 Cornell University 4 * All rights reserved 5 * 6 * The license below extends only to copyright in the software and shall 7 * not be construed as granting a license to any other intellectual 8 * property including but not limited to intellectual property relating 9 * to a hardware implementation of the functionality of the software 10 * licensed hereunder. You may use the software subject to the license 11 * terms below provided that you ensure that this notice is replicated 12 * unmodified and in its entirety in all distributions of the software, 13 * modified or unmodified, in source code or in binary form. 14 * 15 * Redistribution and use in source and binary forms, with or without 16 * modification, are permitted provided that the following conditions are 17 * met: redistributions of source code must retain the above copyright 18 * notice, this list of conditions and the following disclaimer; 19 * redistributions in binary form must reproduce the above copyright 20 * notice, this list of conditions and the following disclaimer in the 21 * documentation and/or other materials provided with the distribution; 22 * neither the name of the copyright holders nor the names of its 23 * contributors may be used to endorse or promote products derived from 24 * this software without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 27 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 28 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 29 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 30 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 31 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 32 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 33 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 34 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 35 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 36 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 37 * 38 * Authors: Vasileios Spiliopoulos 39 * Akash Bagdia 40 * Christopher Torng 41 */ 42 43/** 44 * @file 45 * ClockDomain declarations. 46 */ 47 48#ifndef __SIM_CLOCK_DOMAIN_HH__ 49#define __SIM_CLOCK_DOMAIN_HH__ 50 51#include <algorithm> 52 53#include "base/statistics.hh" 54#include "params/ClockDomain.hh" 55#include "params/DerivedClockDomain.hh" 56#include "params/SrcClockDomain.hh" 57#include "sim/sim_object.hh" 58 59/** 60 * Forward declaration 61 */ 62class DerivedClockDomain; 63class VoltageDomain; 64class ClockedObject; 65 66/** 67 * The ClockDomain provides clock to group of clocked objects bundled 68 * under the same clock domain. The clock domains, in turn, are 69 * grouped into voltage domains. The clock domains provide support for 70 * a hierarchial structure with source and derived domains. 71 */ 72class ClockDomain : public SimObject 73{ 74 75 protected: 76 77 /** 78 * Pre-computed clock period in ticks. This is populated by the 79 * inheriting classes based on how their period is determined. 80 */ 81 Tick _clockPeriod; 82 83 /** 84 * Voltage domain this clock domain belongs to 85 */ 86 VoltageDomain *_voltageDomain; 87 88 /** 89 * Pointers to potential derived clock domains so we can propagate 90 * changes. 91 */ 92 std::vector<DerivedClockDomain*> children; 93 94 /** 95 * Pointers to members of this clock domain, so that when the clock 96 * period changes, we can update each member's tick. 97 */ 98 std::vector<ClockedObject*> members; 99 100 public: 101 102 typedef ClockDomainParams Params; 103 ClockDomain(const Params *p, VoltageDomain *voltage_domain) : 104 SimObject(p), 105 _clockPeriod(0), 106 _voltageDomain(voltage_domain) {} 107 108 /** 109 * Get the clock period. 110 * 111 * @return Clock period in ticks 112 */ 113 inline Tick clockPeriod() const { return _clockPeriod; } 114 115 /** 116 * Register a ClockedObject to this ClockDomain. 117 * 118 * @param ClockedObject to add as a member 119 */ 120 void registerWithClockDomain(ClockedObject *c) 121 { 122 assert(c != NULL); 123 assert(std::find(members.begin(), members.end(), c) == members.end()); 124 members.push_back(c); 125 } 126 127 /** 128 * Get the voltage domain. 129 * 130 * @return Voltage domain this clock domain belongs to 131 */ 132 inline VoltageDomain *voltageDomain() const { return _voltageDomain; } 133 134 135 /** 136 * Get the current voltage this clock domain operates at. 137 * 138 * @return Voltage applied to the clock domain 139 */ 140 inline double voltage() const; 141 142 /** 143 * Add a derived domain. 144 * 145 * @param Derived domain to add as a child 146 */ 147 void addDerivedDomain(DerivedClockDomain *clock_domain) 148 { children.push_back(clock_domain); } 149 150}; 151 152/** 153 * The source clock domains provides the notion of a clock domain that is 154 * connected to a tunable clock source. It maintains the clock period and 155 * provides methods for setting/getting the clock. 156 */ 157class SrcClockDomain : public ClockDomain 158{ 159 160 public: 161 162 typedef SrcClockDomainParams Params; 163 SrcClockDomain(const Params *p); 164 165 /** 166 * Set new clock value 167 * @param clock The new clock period in ticks 168 */ 169 void clockPeriod(Tick clock_period); 170 171 // Explicitly import the otherwise hidden clockPeriod 172 using ClockDomain::clockPeriod; 173}; 174 175/** 176 * The derived clock domains provides the notion of a clock domain 177 * that is connected to a parent clock domain that can either be a 178 * source clock domain or a derived clock domain. It maintains the 179 * clock divider and provides methods for getting the clock. 180 */ 181class DerivedClockDomain: public ClockDomain 182{ 183 184 public: 185 186 typedef DerivedClockDomainParams Params; 187 DerivedClockDomain(const Params *p); 188 189 /** 190 * Called by the parent clock domain to propagate changes. This 191 * also involves propagating the change further to any children of 192 * the derived domain itself. 193 */ 194 void updateClockPeriod(); 195 196 private: 197 198 /** 199 * Reference to the parent clock domain this clock domain derives 200 * its clock period from 201 */ 202 ClockDomain &parent; 203 204 /** 205 * Local clock divider of the domain 206 */ 207 const uint64_t clockDivider; 208}; 209 210#endif 211