src/sim/clock_domain.cc

   1 /*
   2  * Copyright (c) 2013 ARM Limited
   3  * All rights reserved
   4  *
   5  * The license below extends only to copyright in the software and shall
   6  * not be construed as granting a license to any other intellectual
   7  * property including but not limited to intellectual property relating
   8  * to a hardware implementation of the functionality of the software
   9  * licensed hereunder.  You may use the software subject to the license
  10  * terms below provided that you ensure that this notice is replicated
  11  * unmodified and in its entirety in all distributions of the software,
  12  * modified or unmodified, in source code or in binary form.
  13  *
  14  * Redistribution and use in source and binary forms, with or without
  15  * modification, are permitted provided that the following conditions are
  16  * met: redistributions of source code must retain the above copyright
  17  * notice, this list of conditions and the following disclaimer;
  18  * redistributions in binary form must reproduce the above copyright
  19  * notice, this list of conditions and the following disclaimer in the
  20  * documentation and/or other materials provided with the distribution;
  21  * neither the name of the copyright holders nor the names of its
  22  * contributors may be used to endorse or promote products derived from
  23  * this software without specific prior written permission.
  24  *
  25  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  26  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  27  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  28  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  29  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  30  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  31  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  32  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  33  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  34  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  35  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  36  *
  37  * Authors: Vasileios Spiliopoulos
  38  *          Akash Bagdia
  39  *          Andreas Hansson
  40  */
  41
  42 #include "debug/ClockDomain.hh"
  43 #include "params/ClockDomain.hh"
  44 #include "params/DerivedClockDomain.hh"
  45 #include "params/SrcClockDomain.hh"
  46 #include "sim/clock_domain.hh"
  47
  48 SrcClockDomain::SrcClockDomain(const Params *p) : ClockDomain(p)
  49 {
  50     clockPeriod(p->clock);
  51 }
  52
  53 void
  54 SrcClockDomain::clockPeriod(Tick clock_period)
  55 {
  56     if (clock_period == 0) {
  57         fatal("%s has a clock period of zero\n", name());
  58     }
  59
  60     _clockPeriod = clock_period;
  61
  62     DPRINTF(ClockDomain,
  63             "Setting clock period to %d ticks for source clock %s\n",
  64             _clockPeriod, name());
  65
  66     // inform any derived clocks they need to updated their period
  67     for (auto c = children.begin(); c != children.end(); ++c) {
  68         (*c)->updateClockPeriod();
  69     }
  70 }
  71
  72 SrcClockDomain *
  73 SrcClockDomainParams::create()
  74 {
  75     return new SrcClockDomain(this);
  76 }
  77
  78 DerivedClockDomain::DerivedClockDomain(const Params *p) :
  79     ClockDomain(p),
  80     parent(*p->clk_domain),
  81     clockDivider(p->clk_divider)
  82 {
  83     // Ensure that clock divider setting works as frequency divider and never
  84     // work as frequency multiplier
  85     if (clockDivider < 1) {
  86        fatal("Clock divider param cannot be less than 1");
  87     }
  88
  89     // let the parent keep track of this derived domain so that it can
  90     // propagate changes
  91     parent.addDerivedDomain(this);
  92
  93     // update our clock period based on the parents clock
  94     updateClockPeriod();
  95 }
  96
  97 void
  98 DerivedClockDomain::updateClockPeriod()
  99 {
 100     // recalculate the clock period, relying on the fact that changes
 101     // propagate downwards in the tree
 102     _clockPeriod = parent.clockPeriod() * clockDivider;
 103
 104     DPRINTF(ClockDomain,
 105             "Setting clock period to %d ticks for derived clock %s\n",
 106             _clockPeriod, name());
 107
 108     // inform any derived clocks
 109     for (auto c = children.begin(); c != children.end(); ++c) {
 110         (*c)->updateClockPeriod();
 111     }
 112 }
 113
 114 DerivedClockDomain *
 115 DerivedClockDomainParams::create()
 116 {
 117     return new DerivedClockDomain(this);
 118 }