clock_domain.cc revision 9793 
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
48SrcClockDomain::SrcClockDomain(const Params *p) : ClockDomain(p)
49{
50    clockPeriod(p->clock);
51}
52
53void
54SrcClockDomain::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
72SrcClockDomain *
73SrcClockDomainParams::create()
74{
75    return new SrcClockDomain(this);
76}
77
78DerivedClockDomain::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
97void
98DerivedClockDomain::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
114DerivedClockDomain *
115DerivedClockDomainParams::create()
116{
117    return new DerivedClockDomain(this);
118}
119