clock_domain.hh revision 10021:9d6d630f830e
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 private: 76 77 /** 78 * Stat to report clock period of clock domain 79 */ 80 Stats::Value currentClock; 81 82 protected: 83 84 /** 85 * Pre-computed clock period in ticks. This is populated by the 86 * inheriting classes based on how their period is determined. 87 */ 88 Tick _clockPeriod; 89 90 /** 91 * Voltage domain this clock domain belongs to 92 */ 93 VoltageDomain *_voltageDomain; 94 95 /** 96 * Pointers to potential derived clock domains so we can propagate 97 * changes. 98 */ 99 std::vector<DerivedClockDomain*> children; 100 101 /** 102 * Pointers to members of this clock domain, so that when the clock 103 * period changes, we can update each member's tick. 104 */ 105 std::vector<ClockedObject*> members; 106 107 public: 108 109 typedef ClockDomainParams Params; 110 ClockDomain(const Params *p, VoltageDomain *voltage_domain) : 111 SimObject(p), 112 _clockPeriod(0), 113 _voltageDomain(voltage_domain) {} 114 115 void regStats(); 116 117 /** 118 * Get the clock period. 119 * 120 * @return Clock period in ticks 121 */ 122 inline Tick clockPeriod() const { return _clockPeriod; } 123 124 /** 125 * Register a ClockedObject to this ClockDomain. 126 * 127 * @param ClockedObject to add as a member 128 */ 129 void registerWithClockDomain(ClockedObject *c) 130 { 131 assert(c != NULL); 132 assert(std::find(members.begin(), members.end(), c) == members.end()); 133 members.push_back(c); 134 } 135 136 /** 137 * Get the voltage domain. 138 * 139 * @return Voltage domain this clock domain belongs to 140 */ 141 inline VoltageDomain *voltageDomain() const { return _voltageDomain; } 142 143 144 /** 145 * Get the current voltage this clock domain operates at. 146 * 147 * @return Voltage applied to the clock domain 148 */ 149 inline double voltage() const; 150 151 /** 152 * Add a derived domain. 153 * 154 * @param Derived domain to add as a child 155 */ 156 void addDerivedDomain(DerivedClockDomain *clock_domain) 157 { children.push_back(clock_domain); } 158 159}; 160 161/** 162 * The source clock domains provides the notion of a clock domain that is 163 * connected to a tunable clock source. It maintains the clock period and 164 * provides methods for setting/getting the clock. 165 */ 166class SrcClockDomain : public ClockDomain 167{ 168 169 public: 170 171 typedef SrcClockDomainParams Params; 172 SrcClockDomain(const Params *p); 173 174 /** 175 * Set new clock value 176 * @param clock The new clock period in ticks 177 */ 178 void clockPeriod(Tick clock_period); 179 180 // Explicitly import the otherwise hidden clockPeriod 181 using ClockDomain::clockPeriod; 182}; 183 184/** 185 * The derived clock domains provides the notion of a clock domain 186 * that is connected to a parent clock domain that can either be a 187 * source clock domain or a derived clock domain. It maintains the 188 * clock divider and provides methods for getting the clock. 189 */ 190class DerivedClockDomain: public ClockDomain 191{ 192 193 public: 194 195 typedef DerivedClockDomainParams Params; 196 DerivedClockDomain(const Params *p); 197 198 /** 199 * Called by the parent clock domain to propagate changes. This 200 * also involves propagating the change further to any children of 201 * the derived domain itself. 202 */ 203 void updateClockPeriod(); 204 205 private: 206 207 /** 208 * Reference to the parent clock domain this clock domain derives 209 * its clock period from 210 */ 211 ClockDomain &parent; 212 213 /** 214 * Local clock divider of the domain 215 */ 216 const uint64_t clockDivider; 217}; 218 219#endif 220