clock_domain.cc revision 10021
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 * Andreas Hansson 41 * Christopher Torng 42 */ 43 44#include "debug/ClockDomain.hh" 45#include "params/ClockDomain.hh" 46#include "params/DerivedClockDomain.hh" 47#include "params/SrcClockDomain.hh" 48#include "sim/clock_domain.hh" 49#include "sim/voltage_domain.hh" 50#include "sim/clocked_object.hh" 51 52void 53ClockDomain::regStats() 54{ 55 using namespace Stats; 56 57 // Expose the current clock period as a stat for observability in 58 // the dumps 59 currentClock 60 .scalar(_clockPeriod) 61 .name(params()->name + ".clock") 62 .desc("Clock period in ticks") 63 ; 64} 65 66double 67ClockDomain::voltage() const 68{ 69 return _voltageDomain->voltage(); 70} 71 72SrcClockDomain::SrcClockDomain(const Params *p) : 73 ClockDomain(p, p->voltage_domain) 74{ 75 clockPeriod(p->clock); 76} 77 78void 79SrcClockDomain::clockPeriod(Tick clock_period) 80{ 81 if (clock_period == 0) { 82 fatal("%s has a clock period of zero\n", name()); 83 } 84 85 // Align all members to the current tick 86 for (auto m = members.begin(); m != members.end(); ++m) { 87 (*m)->updateClockPeriod(); 88 } 89 90 _clockPeriod = clock_period; 91 92 DPRINTF(ClockDomain, 93 "Setting clock period to %d ticks for source clock %s\n", 94 _clockPeriod, name()); 95 96 // inform any derived clocks they need to updated their period 97 for (auto c = children.begin(); c != children.end(); ++c) { 98 (*c)->updateClockPeriod(); 99 } 100} 101 102SrcClockDomain * 103SrcClockDomainParams::create() 104{ 105 return new SrcClockDomain(this); 106} 107 108DerivedClockDomain::DerivedClockDomain(const Params *p) : 109 ClockDomain(p, p->clk_domain->voltageDomain()), 110 parent(*p->clk_domain), 111 clockDivider(p->clk_divider) 112{ 113 // Ensure that clock divider setting works as frequency divider and never 114 // work as frequency multiplier 115 if (clockDivider < 1) { 116 fatal("Clock divider param cannot be less than 1"); 117 } 118 119 // let the parent keep track of this derived domain so that it can 120 // propagate changes 121 parent.addDerivedDomain(this); 122 123 // update our clock period based on the parents clock 124 updateClockPeriod(); 125} 126 127void 128DerivedClockDomain::updateClockPeriod() 129{ 130 // Align all members to the current tick 131 for (auto m = members.begin(); m != members.end(); ++m) { 132 (*m)->updateClockPeriod(); 133 } 134 135 // recalculate the clock period, relying on the fact that changes 136 // propagate downwards in the tree 137 _clockPeriod = parent.clockPeriod() * clockDivider; 138 139 DPRINTF(ClockDomain, 140 "Setting clock period to %d ticks for derived clock %s\n", 141 _clockPeriod, name()); 142 143 // inform any derived clocks 144 for (auto c = children.begin(); c != children.end(); ++c) { 145 (*c)->updateClockPeriod(); 146 } 147} 148 149DerivedClockDomain * 150DerivedClockDomainParams::create() 151{ 152 return new DerivedClockDomain(this); 153} 154