power: Add voltage domains to the clock domains

This patch adds the notion of voltage domains, and groups clock
domains that operate under the same voltage (i.e. power supply) into
domains. Each clock domain is required to be associated with a voltage
domain, and the latter requires the voltage to be explicitly set.

A voltage domain is an independently controllable voltage supply being
provided to section of the design. Thus, if you wish to perform
dynamic voltage scaling on a CPU, its clock domain should be
associated with a separate voltage domain.

The current implementation of the voltage domain does not take into
consideration cases where there are derived voltage domains running at
ratio of native voltage domains, as with the case where there can be
on-chip buck/boost (charge pumps) voltage regulation logic.

The regression and configuration scripts are updated with a generic
voltage domain for the system, and one for the CPUs.

9 files changed, 273 insertions, 5 deletions

diff --git a/src/python/m5/params.py b/src/python/m5/params.py
index 995c66de5..1e8c24584 100644
--- a/src/python/m5/params.py
+++ b/src/python/m5/params.py
@@ -1250,6 +1250,23 @@ class Clock(ParamValue):
     def ini_str(self):
         return self.period.ini_str()
 
+class Voltage(float,ParamValue):
+    cxx_type = 'double'
+    def __new__(cls, value):
+        # convert to voltage
+        val = convert.toVoltage(value)
+        return super(cls, Voltage).__new__(cls, val)
+
+    def __str__(self):
+        return str(self.val)
+
+    def getValue(self):
+        value = float(self)
+        return value
+
+    def ini_str(self):
+        return '%f' % self.getValue()
+
 class NetworkBandwidth(float,ParamValue):
     cxx_type = 'float'
     def __new__(cls, value):
@@ -1637,7 +1654,7 @@ __all__ = ['Param', 'VectorParam',
            'TcpPort', 'UdpPort', 'EthernetAddr',
            'IpAddress', 'IpNetmask', 'IpWithPort',
            'MemorySize', 'MemorySize32',
-           'Latency', 'Frequency', 'Clock',
+           'Latency', 'Frequency', 'Clock', 'Voltage',
            'NetworkBandwidth', 'MemoryBandwidth',
            'AddrRange',
            'MaxAddr', 'MaxTick', 'AllMemory',
diff --git a/src/python/m5/util/convert.py b/src/python/m5/util/convert.py
index 79f3f985e..26f351e99 100644
--- a/src/python/m5/util/convert.py
+++ b/src/python/m5/util/convert.py
@@ -299,3 +299,15 @@ def toIpWithPort(value):
     if not 0 <= int(port) <= 0xffff:
         raise ValueError, 'invalid port %s' % port
     return (ip, int(port))
+
+def toVoltage(value):
+    if not isinstance(value, str):
+        raise TypeError, "wrong type '%s' should be str" % type(value)
+
+    if value.endswith('mV'):
+        return float(value[:-2]) * milli
+    elif value.endswith('V'):
+        return float(value[:-1])
+
+    raise ValueError, "cannot convert '%s' to voltage" % value
+
diff --git a/src/sim/ClockDomain.py b/src/sim/ClockDomain.py
index 37958dc26..2a3b6addf 100644
--- a/src/sim/ClockDomain.py
+++ b/src/sim/ClockDomain.py
@@ -38,6 +38,7 @@
 
 from m5.params import *
 from m5.SimObject import SimObject
+from m5.proxy import *
 
 # Abstract clock domain
 class ClockDomain(SimObject):
@@ -51,6 +52,9 @@ class SrcClockDomain(ClockDomain):
     cxx_header = "sim/clock_domain.hh"
     clock = Param.Clock("Clock period")
 
+    # A source clock must be associated with a voltage domain
+    voltage_domain = Param.VoltageDomain("Voltage domain")
+
 # Derived clock domain with a parent clock domain and a frequency
 # divider
 class DerivedClockDomain(ClockDomain):
diff --git a/src/sim/SConscript b/src/sim/SConscript
index 7aa4702cd..90d77848b 100644
--- a/src/sim/SConscript
+++ b/src/sim/SConscript
@@ -35,6 +35,7 @@ SimObject('ClockedObject.py')
 SimObject('Root.py')
 SimObject('InstTracer.py')
 SimObject('ClockDomain.py')
+SimObject('VoltageDomain.py')
 
 Source('arguments.cc')
 Source('async.cc')
@@ -52,6 +53,7 @@ Source('simulate.cc')
 Source('stat_control.cc')
 Source('syscall_emul.cc')
 Source('clock_domain.cc')
+Source('voltage_domain.cc')
 
 if env['TARGET_ISA'] != 'no':
     SimObject('Process.py')
@@ -84,3 +86,4 @@ DebugFlag('Timer')
 DebugFlag('VtoPhys')
 DebugFlag('WorkItems')
 DebugFlag('ClockDomain')
+DebugFlag('VoltageDomain')
diff --git a/src/sim/VoltageDomain.py b/src/sim/VoltageDomain.py
new file mode 100644
index 000000000..ad84d756b
--- /dev/null
+++ b/src/sim/VoltageDomain.py
@@ -0,0 +1,47 @@
+# Copyright (c) 2012 ARM Limited
+# All rights reserved.
+#
+# The license below extends only to copyright in the software and shall
+# not be construed as granting a license to any other intellectual
+# property including but not limited to intellectual property relating
+# to a hardware implementation of the functionality of the software
+# licensed hereunder.  You may use the software subject to the license
+# terms below provided that you ensure that this notice is replicated
+# unmodified and in its entirety in all distributions of the software,
+# modified or unmodified, in source code or in binary form.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met: redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer;
+# redistributions in binary form must reproduce the above copyright
+# notice, this list of conditions and the following disclaimer in the
+# documentation and/or other materials provided with the distribution;
+# neither the name of the copyright holders nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+#
+# Authors: Vasileios Spiliopoulos
+#          Akash Bagdia
+
+from m5.SimObject import SimObject
+from m5.params import *
+
+class VoltageDomain(SimObject):
+    type = 'VoltageDomain'
+    cxx_header = "sim/voltage_domain.hh"
+    # We use a default voltage of 1V to avoid forcing users to set it
+    # even if they are not interested in using the functionality
+    voltage = Param.Voltage('1V', "Operational voltage")
diff --git a/src/sim/clock_domain.cc b/src/sim/clock_domain.cc
index 262ae904c..8b563d598 100644
--- a/src/sim/clock_domain.cc
+++ b/src/sim/clock_domain.cc
@@ -44,8 +44,16 @@
 #include "params/DerivedClockDomain.hh"
 #include "params/SrcClockDomain.hh"
 #include "sim/clock_domain.hh"
+#include "sim/voltage_domain.hh"
 
-SrcClockDomain::SrcClockDomain(const Params *p) : ClockDomain(p)
+double
+ClockDomain::voltage() const
+{
+    return _voltageDomain->voltage();
+}
+
+SrcClockDomain::SrcClockDomain(const Params *p) :
+    ClockDomain(p, p->voltage_domain)
 {
     clockPeriod(p->clock);
 }
@@ -76,7 +84,7 @@ SrcClockDomainParams::create()
 }
 
 DerivedClockDomain::DerivedClockDomain(const Params *p) :
-    ClockDomain(p),
+    ClockDomain(p, p->clk_domain->voltageDomain()),
     parent(*p->clk_domain),
     clockDivider(p->clk_divider)
 {
diff --git a/src/sim/clock_domain.hh b/src/sim/clock_domain.hh
index c3f53e675..619f30696 100644
--- a/src/sim/clock_domain.hh
+++ b/src/sim/clock_domain.hh
@@ -56,10 +56,12 @@
  * Forward declaration
  */
 class DerivedClockDomain;
+class VoltageDomain;
 
 /**
  * The ClockDomain provides clock to group of clocked objects bundled
- * under the same clock domain. The clock domains provide support for
+ * under the same clock domain. The clock domains, in turn, are
+ * grouped into voltage domains. The clock domains provide support for
  * a hierarchial structure with source and derived domains.
  */
 class ClockDomain : public SimObject
@@ -74,6 +76,11 @@ class ClockDomain : public SimObject
     Tick _clockPeriod;
 
     /**
+     * Voltage domain this clock domain belongs to
+     */
+    VoltageDomain *_voltageDomain;
+
+    /**
      * Pointers to potential derived clock domains so we can propagate
      * changes.
      */
@@ -82,7 +89,10 @@ class ClockDomain : public SimObject
   public:
 
     typedef ClockDomainParams Params;
-    ClockDomain(const Params *p) : SimObject(p), _clockPeriod(0) {}
+    ClockDomain(const Params *p, VoltageDomain *voltage_domain) :
+        SimObject(p),
+        _clockPeriod(0),
+        _voltageDomain(voltage_domain) {}
 
     /**
      * Get the clock period.
@@ -92,6 +102,21 @@ class ClockDomain : public SimObject
     inline Tick clockPeriod() const { return _clockPeriod; }
 
     /**
+     * Get the voltage domain.
+     *
+     * @return Voltage domain this clock domain belongs to
+     */
+    inline VoltageDomain *voltageDomain() const { return _voltageDomain; }
+
+
+    /**
+     * Get the current voltage this clock domain operates at.
+     *
+     * @return Voltage applied to the clock domain
+     */
+    inline double voltage() const;
+
+    /**
      * Add a derived domain.
      *
      * @param Derived domain to add as a child
diff --git a/src/sim/voltage_domain.cc b/src/sim/voltage_domain.cc
new file mode 100644
index 000000000..43848d68a
--- /dev/null
+++ b/src/sim/voltage_domain.cc
@@ -0,0 +1,68 @@
+/*
+ * Copyright (c) 2012 ARM Limited
+ * All rights reserved
+ *
+ * The license below extends only to copyright in the software and shall
+ * not be construed as granting a license to any other intellectual
+ * property including but not limited to intellectual property relating
+ * to a hardware implementation of the functionality of the software
+ * licensed hereunder.  You may use the software subject to the license
+ * terms below provided that you ensure that this notice is replicated
+ * unmodified and in its entirety in all distributions of the software,
+ * modified or unmodified, in source code or in binary form.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met: redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer;
+ * redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution;
+ * neither the name of the copyright holders nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * Authors: Vasileios Spiliopoulos
+ *          Akash Bagdia
+ */
+
+#include "debug/VoltageDomain.hh"
+#include "params/VoltageDomain.hh"
+#include "sim/sim_object.hh"
+#include "sim/voltage_domain.hh"
+
+VoltageDomain::VoltageDomain(const Params *p)
+    : SimObject(p), _voltage(0)
+{
+    voltage(p->voltage);
+}
+
+void
+VoltageDomain::voltage(double voltage)
+{
+    if (voltage <= 0) {
+        fatal("Voltage should be greater than zero.\n");
+    }
+
+    _voltage = voltage;
+    DPRINTF(VoltageDomain,
+            "Setting voltage to %f for domain %s\n", _voltage, name());
+}
+
+VoltageDomain *
+VoltageDomainParams::create()
+{
+    return new VoltageDomain(this);
+}
diff --git a/src/sim/voltage_domain.hh b/src/sim/voltage_domain.hh
new file mode 100644
index 000000000..585ec8d66
--- /dev/null
+++ b/src/sim/voltage_domain.hh
@@ -0,0 +1,84 @@
+/*
+ * Copyright (c) 2012 ARM Limited
+ * All rights reserved
+ *
+ * The license below extends only to copyright in the software and shall
+ * not be construed as granting a license to any other intellectual
+ * property including but not limited to intellectual property relating
+ * to a hardware implementation of the functionality of the software
+ * licensed hereunder.  You may use the software subject to the license
+ * terms below provided that you ensure that this notice is replicated
+ * unmodified and in its entirety in all distributions of the software,
+ * modified or unmodified, in source code or in binary form.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met: redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer;
+ * redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution;
+ * neither the name of the copyright holders nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * Authors: Vasileios Spiliopoulos
+ *          Akash Bagdia
+ */
+
+#ifndef __SIM_VOLTAGE_DOMAIN_HH__
+#define __SIM_VOLTAGE_DOMAIN_HH__
+
+#include "base/statistics.hh"
+#include "params/VoltageDomain.hh"
+#include "sim/sim_object.hh"
+
+/**
+ * A VoltageDomain is used to group clock domains that operate under
+ * the same voltage. The class provides methods for setting and
+ * getting the voltage.
+ */
+class VoltageDomain : public SimObject
+{
+
+  private:
+
+    /**
+     * The voltage of the domain expressed in Volts
+     */
+    double _voltage;
+
+  public:
+
+    typedef VoltageDomainParams Params;
+    VoltageDomain(const Params *p);
+
+    /**
+     * Get the current volate.
+     *
+     * @return Voltage of the domain
+     */
+    inline double voltage() const { return _voltage; }
+
+    /**
+     * Set the voltage of the domain.
+     *
+     * @param Voltage value to be set
+     */
+    void voltage(double voltage);
+
+};
+
+#endif