ARM: Add per-cpu local timers for ARM.

Cortex-A9 processors can have a local timer and watchdog counter. It
is enabled by default in Linux and up to this point we've had to disable
them since a model wasn't available. This change allows a default
MP ARM Linux configuration to boot.

1 files changed, 440 insertions, 0 deletions

diff --git a/src/dev/arm/timer_cpulocal.cc b/src/dev/arm/timer_cpulocal.cc
new file mode 100644
index 000000000..a3a126f2f
--- /dev/null
+++ b/src/dev/arm/timer_cpulocal.cc
@@ -0,0 +1,440 @@
+/*
+ * Copyright (c) 2010-2011 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: Ali Saidi
+ *          Geoffrey Blake
+ */
+
+#include "base/intmath.hh"
+#include "base/trace.hh"
+#include "debug/Checkpoint.hh"
+#include "debug/Timer.hh"
+#include "dev/arm/gic.hh"
+#include "dev/arm/timer_cpulocal.hh"
+#include "mem/packet.hh"
+#include "mem/packet_access.hh"
+
+CpuLocalTimer::CpuLocalTimer(Params *p)
+    : BasicPioDevice(p), gic(p->gic)
+{
+   // Initialize the timer registers for each per cpu timer
+   for (int i = 0; i < CPU_MAX; i++) {
+        std::stringstream oss;
+        oss << name() << ".timer" << i;
+        localTimer[i]._name = oss.str();
+        localTimer[i].parent = this;
+        localTimer[i].intNumTimer = p->int_num_timer;
+        localTimer[i].intNumWatchdog = p->int_num_watchdog;
+        localTimer[i].clock = p->clock;
+        localTimer[i].cpuNum = i;
+    }
+    pioSize = 0x38;
+}
+
+CpuLocalTimer::Timer::Timer()
+    : timerControl(0x0), watchdogControl(0x0), rawIntTimer(false), rawIntWatchdog(false),
+      rawResetWatchdog(false), watchdogDisableReg(0x0), pendingIntTimer(false), pendingIntWatchdog(false),
+      timerLoadValue(0x0), watchdogLoadValue(0x0), timerZeroEvent(this), watchdogZeroEvent(this)
+{
+}
+
+Tick
+CpuLocalTimer::read(PacketPtr pkt)
+{
+    assert(pkt->getAddr() >= pioAddr && pkt->getAddr() < pioAddr + pioSize);
+    assert(pkt->getSize() == 4);
+    Addr daddr = pkt->getAddr() - pioAddr;
+    pkt->allocate();
+    int cpu_id = pkt->req->contextId();
+    DPRINTF(Timer, "Reading from CpuLocalTimer at offset: %#x\n", daddr);
+    assert(cpu_id >= 0);
+    assert(cpu_id < CPU_MAX);
+
+    if (daddr < Timer::Size)
+        localTimer[cpu_id].read(pkt, daddr);
+    else
+        panic("Tried to read CpuLocalTimer at offset %#x that doesn't exist\n", daddr);
+    pkt->makeAtomicResponse();
+    return pioDelay;
+}
+
+
+void
+CpuLocalTimer::Timer::read(PacketPtr pkt, Addr daddr)
+{
+    DPRINTF(Timer, "Reading from CpuLocalTimer at offset: %#x\n", daddr);
+    Tick time;
+
+    switch(daddr) {
+      case TimerLoadReg:
+        pkt->set<uint32_t>(timerLoadValue);
+        break;
+      case TimerCounterReg:
+        DPRINTF(Timer, "Event schedule for timer %d, clock=%d, prescale=%d\n",
+                timerZeroEvent.when(), clock, timerControl.prescalar);
+        time = timerZeroEvent.when() - curTick();
+        time = time / clock / power(16, timerControl.prescalar);
+        DPRINTF(Timer, "-- returning counter at %d\n", time);
+        pkt->set<uint32_t>(time);
+        break;
+      case TimerControlReg:
+        pkt->set<uint32_t>(timerControl);
+        break;
+      case TimerIntStatusReg:
+        pkt->set<uint32_t>(rawIntTimer);
+        break;
+      case WatchdogLoadReg:
+        pkt->set<uint32_t>(watchdogLoadValue);
+        break;
+      case WatchdogCounterReg:
+        DPRINTF(Timer, "Event schedule for watchdog %d, clock=%d, prescale=%d\n",
+                watchdogZeroEvent.when(), clock, watchdogControl.prescalar);
+        time = watchdogZeroEvent.when() - curTick();
+        time = time / clock / power(16, watchdogControl.prescalar);
+        DPRINTF(Timer, "-- returning counter at %d\n", time);
+        pkt->set<uint32_t>(time);
+        break;
+      case WatchdogControlReg:
+        pkt->set<uint32_t>(watchdogControl);
+        break;
+      case WatchdogIntStatusReg:
+        pkt->set<uint32_t>(rawIntWatchdog);
+        break;
+      case WatchdogResetStatusReg:
+        pkt->set<uint32_t>(rawResetWatchdog);
+        break;
+      case WatchdogDisableReg:
+        panic("Tried to read from WatchdogDisableRegister\n");
+        break;
+      default:
+        panic("Tried to read CpuLocalTimer at offset %#x\n", daddr);
+        break;
+    }
+}
+
+Tick
+CpuLocalTimer::write(PacketPtr pkt)
+{
+    assert(pkt->getAddr() >= pioAddr && pkt->getAddr() < pioAddr + pioSize);
+    assert(pkt->getSize() == 4);
+    Addr daddr = pkt->getAddr() - pioAddr;
+    pkt->allocate();
+    int cpu_id = pkt->req->contextId();
+    DPRINTF(Timer, "Writing to CpuLocalTimer at offset: %#x\n", daddr);
+    assert(cpu_id >= 0);
+    assert(cpu_id < CPU_MAX);
+
+    if (daddr < Timer::Size)
+        localTimer[cpu_id].write(pkt, daddr);
+    else
+        panic("Tried to write CpuLocalTimer at offset %#x that doesn't exist\n", daddr);
+    pkt->makeAtomicResponse();
+    return pioDelay;
+}
+
+void
+CpuLocalTimer::Timer::write(PacketPtr pkt, Addr daddr)
+{
+    DPRINTF(Timer, "Writing to CpuLocalTimer at offset: %#x\n", daddr);
+    bool old_enable;
+    bool old_wd_mode;
+    uint32_t old_val;
+
+    switch (daddr) {
+      case TimerLoadReg:
+        // Writing to this register also resets the counter register and
+        // starts decrementing if the counter is enabled.
+        timerLoadValue = pkt->get<uint32_t>();
+        restartTimerCounter(timerLoadValue);
+        break;
+      case TimerCounterReg:
+        // Can be written, doesn't start counting unless the timer is enabled
+        restartTimerCounter(pkt->get<uint32_t>());
+        break;
+      case TimerControlReg:
+        old_enable = timerControl.enable;
+        timerControl = pkt->get<uint32_t>();
+        if ((old_enable == 0) && timerControl.enable)
+            restartTimerCounter(timerLoadValue);
+        break;
+      case TimerIntStatusReg:
+        rawIntTimer = false;
+        if (pendingIntTimer) {
+            pendingIntTimer = false;
+            DPRINTF(Timer, "Clearing interrupt\n");
+        }
+        break;
+      case WatchdogLoadReg:
+        watchdogLoadValue = pkt->get<uint32_t>();
+        restartWatchdogCounter(watchdogLoadValue);
+        break;
+      case WatchdogCounterReg:
+        // Can't be written when in watchdog mode, but can in timer mode
+        if (!watchdogControl.watchdogMode) {
+            restartWatchdogCounter(pkt->get<uint32_t>());
+        }
+        break;
+      case WatchdogControlReg:
+        old_enable = watchdogControl.enable;
+        old_wd_mode = watchdogControl.watchdogMode;
+        watchdogControl = pkt->get<uint32_t>();
+        if ((old_enable == 0) && watchdogControl.enable)
+            restartWatchdogCounter(watchdogLoadValue);
+        // cannot disable watchdog using control register
+        if ((old_wd_mode == 1) && watchdogControl.watchdogMode == 0)
+            watchdogControl.watchdogMode = 1;
+        break;
+      case WatchdogIntStatusReg:
+        rawIntWatchdog = false;
+        if (pendingIntWatchdog) {
+            pendingIntWatchdog = false;
+            DPRINTF(Timer, "Clearing watchdog interrupt\n");
+        }
+        break;
+      case WatchdogResetStatusReg:
+        rawResetWatchdog = false;
+        DPRINTF(Timer, "Clearing watchdog reset flag\n");
+        break;
+      case WatchdogDisableReg:
+        old_val = watchdogDisableReg;
+        watchdogDisableReg = pkt->get<uint32_t>();
+        // if this sequence is observed, turn off watchdog mode
+        if (old_val == 0x12345678 && watchdogDisableReg == 0x87654321)
+            watchdogControl.watchdogMode = 0;
+        break;
+      default:
+        panic("Tried to write CpuLocalTimer timer at offset %#x\n", daddr);
+        break;
+    }
+}
+
+//XXX: Two functions are needed because the control registers are different types
+void
+CpuLocalTimer::Timer::restartTimerCounter(uint32_t val)
+{
+    DPRINTF(Timer, "Resetting timer counter with value %#x\n", val);
+    if (!timerControl.enable)
+        return;
+
+    Tick time = clock * power(16, timerControl.prescalar);
+    time *= val;
+
+    if (timerZeroEvent.scheduled()) {
+        DPRINTF(Timer, "-- Event was already schedule, de-scheduling\n");
+        parent->deschedule(timerZeroEvent);
+    }
+    parent->schedule(timerZeroEvent, curTick() + time);
+    DPRINTF(Timer, "-- Scheduling new event for: %d\n", curTick() + time);
+}
+
+void
+CpuLocalTimer::Timer::restartWatchdogCounter(uint32_t val)
+{
+    DPRINTF(Timer, "Resetting watchdog counter with value %#x\n", val);
+    if (!watchdogControl.enable)
+        return;
+
+    Tick time = clock * power(16, watchdogControl.prescalar);
+    time *= val;
+
+    if (watchdogZeroEvent.scheduled()) {
+        DPRINTF(Timer, "-- Event was already schedule, de-scheduling\n");
+        parent->deschedule(watchdogZeroEvent);
+    }
+    parent->schedule(watchdogZeroEvent, curTick() + time);
+    DPRINTF(Timer, "-- Scheduling new event for: %d\n", curTick() + time);
+}
+//////
+
+void
+CpuLocalTimer::Timer::timerAtZero()
+{
+    if (!timerControl.enable)
+        return;
+
+    DPRINTF(Timer, "Timer Counter reached zero\n");
+
+    rawIntTimer = true;
+    bool old_pending = pendingIntTimer;
+    if (timerControl.intEnable)
+        pendingIntTimer = true;
+    if (pendingIntTimer && ~old_pending) {
+        DPRINTF(Timer, "-- Causing interrupt\n");
+        parent->gic->sendPPInt(intNumTimer, cpuNum);
+    }
+
+    if (!timerControl.autoReload)
+        return;
+    else
+        restartTimerCounter(timerLoadValue);
+}
+
+void
+CpuLocalTimer::Timer::watchdogAtZero()
+{
+    if (!watchdogControl.enable)
+        return;
+
+    DPRINTF(Timer, "Watchdog Counter reached zero\n");
+
+    rawIntWatchdog = true;
+    bool old_pending = pendingIntWatchdog;
+    // generates an interrupt only if the watchdog is in timer
+    // mode.
+    if (watchdogControl.intEnable && !watchdogControl.watchdogMode)
+        pendingIntWatchdog = true;
+    else if (watchdogControl.watchdogMode) {
+        rawResetWatchdog = true;
+        fatal("gem5 ARM Model does not support true watchdog operation!\n");
+        //XXX: Should we ever support a true watchdog reset?
+    }
+
+    if (pendingIntWatchdog && ~old_pending) {
+        DPRINTF(Timer, "-- Causing interrupt\n");
+        parent->gic->sendPPInt(intNumWatchdog, cpuNum);
+    }
+
+    if (watchdogControl.watchdogMode)
+        return;
+    else if (watchdogControl.autoReload)
+        restartWatchdogCounter(watchdogLoadValue);
+}
+
+void
+CpuLocalTimer::Timer::serialize(std::ostream &os)
+{
+    DPRINTF(Checkpoint, "Serializing Arm CpuLocalTimer\n");
+    SERIALIZE_SCALAR(intNumTimer);
+    SERIALIZE_SCALAR(intNumWatchdog);
+    SERIALIZE_SCALAR(clock);
+
+    uint32_t timer_control_serial = timerControl;
+    uint32_t watchdog_control_serial = watchdogControl;
+    SERIALIZE_SCALAR(timer_control_serial);
+    SERIALIZE_SCALAR(watchdog_control_serial);
+
+    SERIALIZE_SCALAR(rawIntTimer);
+    SERIALIZE_SCALAR(rawIntWatchdog);
+    SERIALIZE_SCALAR(rawResetWatchdog);
+    SERIALIZE_SCALAR(watchdogDisableReg);
+    SERIALIZE_SCALAR(pendingIntTimer);
+    SERIALIZE_SCALAR(pendingIntWatchdog);
+    SERIALIZE_SCALAR(timerLoadValue);
+    SERIALIZE_SCALAR(watchdogLoadValue);
+
+    bool timer_is_in_event = timerZeroEvent.scheduled();
+    SERIALIZE_SCALAR(timer_is_in_event);
+    bool watchdog_is_in_event = watchdogZeroEvent.scheduled();
+    SERIALIZE_SCALAR(watchdog_is_in_event);
+
+    Tick timer_event_time;
+    if (timer_is_in_event){
+        timer_event_time = timerZeroEvent.when();
+        SERIALIZE_SCALAR(timer_event_time);
+    }
+    Tick watchdog_event_time;
+    if (watchdog_is_in_event){
+        watchdog_event_time = watchdogZeroEvent.when();
+        SERIALIZE_SCALAR(watchdog_event_time);
+    }
+}
+
+void
+CpuLocalTimer::Timer::unserialize(Checkpoint *cp, const std::string &section)
+{
+    DPRINTF(Checkpoint, "Unserializing Arm CpuLocalTimer\n");
+
+    UNSERIALIZE_SCALAR(intNumTimer);
+    UNSERIALIZE_SCALAR(intNumWatchdog);
+    UNSERIALIZE_SCALAR(clock);
+
+    uint32_t timer_control_serial;
+    UNSERIALIZE_SCALAR(timer_control_serial);
+    timerControl = timer_control_serial;
+    uint32_t watchdog_control_serial;
+    UNSERIALIZE_SCALAR(watchdog_control_serial);
+    watchdogControl = watchdog_control_serial;
+
+    UNSERIALIZE_SCALAR(rawIntTimer);
+    UNSERIALIZE_SCALAR(rawIntWatchdog);
+    UNSERIALIZE_SCALAR(rawResetWatchdog);
+    UNSERIALIZE_SCALAR(watchdogDisableReg);
+    UNSERIALIZE_SCALAR(pendingIntTimer);
+    UNSERIALIZE_SCALAR(pendingIntWatchdog);
+    UNSERIALIZE_SCALAR(timerLoadValue);
+    UNSERIALIZE_SCALAR(watchdogLoadValue);
+
+    bool timer_is_in_event;
+    UNSERIALIZE_SCALAR(timer_is_in_event);
+    bool watchdog_is_in_event;
+    UNSERIALIZE_SCALAR(watchdog_is_in_event);
+
+    Tick timer_event_time;
+    if (timer_is_in_event){
+        UNSERIALIZE_SCALAR(timer_event_time);
+        parent->schedule(timerZeroEvent, timer_event_time);
+    }
+    Tick watchdog_event_time;
+    if (watchdog_is_in_event) {
+        UNSERIALIZE_SCALAR(watchdog_event_time);
+        parent->schedule(watchdogZeroEvent, watchdog_event_time);
+    }
+}
+
+
+
+void
+CpuLocalTimer::serialize(std::ostream &os)
+{
+    for (int i = 0; i < CPU_MAX; i++) {
+        nameOut(os, csprintf("%s.timer%d", name(), i));
+        localTimer[i].serialize(os);
+    }
+}
+
+void
+CpuLocalTimer::unserialize(Checkpoint *cp, const std::string &section)
+{
+    for (int i = 0; i < CPU_MAX; i++) {
+        localTimer[i].unserialize(cp, csprintf("%s.timer%d", section, i));
+    }
+}
+
+CpuLocalTimer *
+CpuLocalTimerParams::create()
+{
+    return new CpuLocalTimer(this);
+}