x86: Move APIC clock divider to Python

This patch moves the 16x APIC clock divider to the Python code to
avoid the post-instantiation modifications to the clock. The x86 APIC
was the only object setting the clock after creation time and this
required some custom functionality and configuration. With this patch,
the clock multiplier is moved to the Python code and the objects are
instantiated with the appropriate clock.

3 files changed, 7 insertions, 21 deletions

diff --git a/src/arch/x86/interrupts.cc b/src/arch/x86/interrupts.cc
index 8eae2d390..c693e6bbd 100644
--- a/src/arch/x86/interrupts.cc
+++ b/src/arch/x86/interrupts.cc
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2012 ARM Limited
+ * Copyright (c) 2012-2013 ARM Limited
  * All rights reserved
  *
  * The license below extends only to copyright in the software and shall
@@ -410,9 +410,8 @@ X86ISA::Interrupts::readReg(ApicRegIndex reg)
       case APIC_CURRENT_COUNT:
         {
             if (apicTimerEvent.scheduled()) {
-                assert(clock);
                 // Compute how many m5 ticks happen per count.
-                uint64_t ticksPerCount = clock *
+                uint64_t ticksPerCount = clockPeriod() *
                     divideFromConf(regs[APIC_DIVIDE_CONFIGURATION]);
                 // Compute how many m5 ticks are left.
                 uint64_t val = apicTimerEvent.when() - curTick();
@@ -587,19 +586,20 @@ X86ISA::Interrupts::setReg(ApicRegIndex reg, uint32_t val)
         break;
       case APIC_INITIAL_COUNT:
         {
-            assert(clock);
             newVal = bits(val, 31, 0);
             // Compute how many timer ticks we're being programmed for.
             uint64_t newCount = newVal *
                 (divideFromConf(regs[APIC_DIVIDE_CONFIGURATION]));
             // Schedule on the edge of the next tick plus the new count.
-            Tick offset = curTick() % clock;
+            Tick offset = curTick() % clockPeriod();
             if (offset) {
                 reschedule(apicTimerEvent,
-                        curTick() + (newCount + 1) * clock - offset, true);
+                           curTick() + (newCount + 1) *
+                           clockPeriod() - offset, true);
             } else {
                 reschedule(apicTimerEvent,
-                        curTick() + newCount * clock, true);
+                           curTick() + newCount *
+                           clockPeriod(), true);
             }
         }
         break;
@@ -629,8 +629,6 @@ X86ISA::Interrupts::Interrupts(Params * p) :
     pendingIPIs(0), cpu(NULL),
     intSlavePort(name() + ".int_slave", this, this, latency)
 {
-    // Override the default clock
-    clock = 0;
     pioSize = PageBytes;
     memset(regs, 0, sizeof(regs));
     //Set the local apic DFR to the flat model.
@@ -735,7 +733,6 @@ void
 X86ISA::Interrupts::serialize(std::ostream &os)
 {
     SERIALIZE_ARRAY(regs, NUM_APIC_REGS);
-    SERIALIZE_SCALAR(clock);
     SERIALIZE_SCALAR(pendingSmi);
     SERIALIZE_SCALAR(smiVector);
     SERIALIZE_SCALAR(pendingNmi);
@@ -761,7 +758,6 @@ void
 X86ISA::Interrupts::unserialize(Checkpoint *cp, const std::string &section)
 {
     UNSERIALIZE_ARRAY(regs, NUM_APIC_REGS);
-    UNSERIALIZE_SCALAR(clock);
     UNSERIALIZE_SCALAR(pendingSmi);
     UNSERIALIZE_SCALAR(smiVector);
     UNSERIALIZE_SCALAR(pendingNmi);
diff --git a/src/arch/x86/interrupts.hh b/src/arch/x86/interrupts.hh
index 06094f0b1..4e6ef4324 100644
--- a/src/arch/x86/interrupts.hh
+++ b/src/arch/x86/interrupts.hh
@@ -201,12 +201,6 @@ class Interrupts : public BasicPioDevice, IntDev
 
     void setCPU(BaseCPU * newCPU);
 
-    void
-    setClock(Tick newClock)
-    {
-        clock = newClock;
-    }
-
     const Params *
     params() const
     {
diff --git a/src/arch/x86/utility.cc b/src/arch/x86/utility.cc
index e56e96b99..ae6c37be6 100644
--- a/src/arch/x86/utility.cc
+++ b/src/arch/x86/utility.cc
@@ -174,10 +174,6 @@ void initCPU(ThreadContext *tc, int cpuId)
 
     interrupts->setRegNoEffect(APIC_VERSION, (5 << 16) | 0x14);
 
-    // @todo: Control the relative frequency, in this case 16:1, of
-    // the clocks in the Python code
-    interrupts->setClock(tc->getCpuPtr()->clockPeriod() * 16);
-
     // TODO Set the SMRAM base address (SMBASE) to 0x00030000
 
     tc->setMiscReg(MISCREG_VM_CR, 0);