1 files changed, 80 insertions, 12 deletions

diff --git a/src/sim/voltage_domain.cc b/src/sim/voltage_domain.cc
index 461e672ea..b5673feda 100644
--- a/src/sim/voltage_domain.cc
+++ b/src/sim/voltage_domain.cc
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2012 ARM Limited
+ * Copyright (c) 2012-2014 ARM Limited
  * All rights reserved
  *
  * The license below extends only to copyright in the software and shall
@@ -38,36 +38,93 @@
  *          Akash Bagdia
  */
 
+#include <algorithm>
+
+#include "base/statistics.hh"
 #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)
+    : SimObject(p), voltageOpPoints(p->voltage), _perfLevel(0)
 {
-    voltage(p->voltage);
+    fatal_if(voltageOpPoints.empty(), "DVFS: Empty set of voltages for "\
+             "voltage domain %s\n", name());
+
+    // Voltages must be sorted in descending order.
+    fatal_if(!std::is_sorted(voltageOpPoints.begin(), voltageOpPoints.end(),
+             std::greater_equal<Voltages::value_type>()), "DVFS: Voltage "\
+             "operation points not in descending order for voltage domain "\
+             "%s\n", name());
 }
 
 void
-VoltageDomain::voltage(double voltage)
+VoltageDomain::perfLevel(PerfLevel perf_level)
+{
+    chatty_assert(perf_level < voltageOpPoints.size(),
+                  "DVFS: Requested voltage ID %d is outside the known "\
+                  "range for domain %s.\n", perf_level, name());
+
+    _perfLevel = perf_level;
+
+    DPRINTF(VoltageDomain, "Setting voltage to %.3fV idx: %d for domain %s\n",
+            voltage(), perf_level, name());
+}
+
+bool
+VoltageDomain::sanitiseVoltages()
 {
-    if (voltage <= 0) {
-        fatal("Voltage should be greater than zero.\n");
+    if (numVoltages() == 1)
+        return false;
+
+    // Find the highest requested performance level and update the voltage
+    // domain with it
+    PerfLevel perf_max = (PerfLevel)-1;
+    for (auto dit = srcClockChildren.begin(); dit != srcClockChildren.end(); ++dit) {
+        SrcClockDomain* d = *dit;
+        chatty_assert(d->voltageDomain() == this, "DVFS: Clock domain %s "\
+                      "(id: %d) should not be registered with voltage domain "\
+                      "%s\n", d->name(), d->domainID(), name());
+
+        PerfLevel perf = d->perfLevel();
+
+        DPRINTF(VoltageDomain, "DVFS: Clock domain %s (id: %d) requests perf "\
+                "level %d\n", d->name(), d->domainID(), perf);
+
+        // NOTE: Descending sort of performance levels: 0 - fast, 5 - slow
+        if (perf < perf_max) {
+            DPRINTF(VoltageDomain, "DVFS: Updating max perf level %d -> %d\n",
+                    perf_max, perf);
+            perf_max = perf;
+        }
     }
+    DPRINTF(VoltageDomain, "DVFS: Setting perf level of voltage domain %s "\
+            "from %d to %d.\n", name(), perfLevel(), perf_max);
 
-    _voltage = voltage;
-    DPRINTF(VoltageDomain,
-            "Setting voltage to %f for domain %s\n", _voltage, name());
+    // Set the performance level
+    if (perf_max != perfLevel()) {
+        perfLevel(perf_max);
+        return true;
+    } else {
+        return false;
+    }
+}
+
+void
+VoltageDomain::startup() {
+    bool changed = sanitiseVoltages();
+    if (changed) {
+        warn("DVFS: Perf level for voltage domain %s adapted to "\
+             "requested perf levels from source clock domains.\n", name());
+    }
 }
 
 void
 VoltageDomain::regStats()
 {
-    using namespace Stats;
-
     currentVoltage
-        .scalar(_voltage)
+        .method(this, &VoltageDomain::voltage)
         .name(params()->name + ".voltage")
         .desc("Voltage in Volts")
         ;
@@ -78,3 +135,14 @@ VoltageDomainParams::create()
 {
     return new VoltageDomain(this);
 }
+
+void
+VoltageDomain::serialize(std::ostream &os) {
+    SERIALIZE_SCALAR(_perfLevel);
+}
+
+void
+VoltageDomain::unserialize(Checkpoint *cp, const std::string &section) {
+    UNSERIALIZE_SCALAR(_perfLevel);
+    perfLevel(_perfLevel);
+}