Implement APIC timer initialization and calibration

xtoskrnl/CMakeLists.txt

@@ -21,6 +21,7 @@ list(APPEND XTOSKRNL_SOURCE
     ${XTOSKRNL_SOURCE_DIR}/hl/${ARCH}/ioport.cc
     ${XTOSKRNL_SOURCE_DIR}/hl/${ARCH}/irq.cc
     ${XTOSKRNL_SOURCE_DIR}/hl/${ARCH}/runlevel.cc
+    ${XTOSKRNL_SOURCE_DIR}/hl/${ARCH}/timer.cc
     ${XTOSKRNL_SOURCE_DIR}/hl/acpi.cc
     ${XTOSKRNL_SOURCE_DIR}/hl/cport.cc
     ${XTOSKRNL_SOURCE_DIR}/hl/data.cc

xtoskrnl/hl/amd64/timer.cc

@@ -0,0 +1,13 @@
+/**
+ * PROJECT:         ExectOS
+ * COPYRIGHT:       See COPYING.md in the top level directory
+ * FILE:            xtoskrnl/hl/amd64/timer.cc
+ * DESCRIPTION:     APIC Timer for AMD64 support
+ * DEVELOPERS:      Aiken Harris <harraiken91@gmail.com>
+ */
+
+#include <xtos.hh>
+
+
+/* Include common Timer interface */
+#include ARCH_COMMON(timer.cc)

xtoskrnl/hl/i686/timer.cc

@@ -0,0 +1,13 @@
+/**
+ * PROJECT:         ExectOS
+ * COPYRIGHT:       See COPYING.md in the top level directory
+ * FILE:            xtoskrnl/hl/i686/timer.cc
+ * DESCRIPTION:     APIC Timer for i686 support
+ * DEVELOPERS:      Aiken Harris <harraiken91@gmail.com>
+ */
+
+#include <xtos.hh>
+
+
+/* Include common Timer interface */
+#include ARCH_COMMON(timer.cc)

xtoskrnl/hl/x86/timer.cc

@@ -0,0 +1,350 @@
+/**
+ * PROJECT:         ExectOS
+ * COPYRIGHT:       See COPYING.md in the top level directory
+ * FILE:            xtoskrnl/hl/x86/timer.cc
+ * DESCRIPTION:     APIC Timer support for x86 (i686/AMD64) support
+ * DEVELOPERS:      Aiken Harris <harraiken91@gmail.com>
+ */
+
+#include <xtos.hh>
+
+
+/**
+ * Calibrates the Local APIC timer frequency.
+ *
+ * @return This routine returns a status code.
+ *
+ * @since XT 1.0
+ */
+XTAPI
+XTSTATUS
+HL::Timer::CalibrateApicTimer()
+{
+    ULONG CurrentCount, Frequency, InitialCount;
+    XTSTATUS Status;
+
+    /* Get APIC timer frequency from the Core Crystal Clock */
+    Status = GetApicTimerFrequency(&Frequency);
+    if(Status != STATUS_SUCCESS || !Frequency)
+    {
+        /* CCC unavailable, fallback to PIT calibration */
+        InitialCount = 0xFFFFFFFF;
+
+        /* Load the initial count into the APIC Timer and begin the countdown */
+        HL::Pic::WriteApicRegister(APIC_TICR, InitialCount);
+
+        /* Wait for 10ms */
+        StallExecution(10000);
+
+        /* Read current tick count from APIC timer and clear APIC timer */
+        CurrentCount = HL::Pic::ReadApicRegister(APIC_TCCR);
+        HL::Pic::WriteApicRegister(APIC_TICR, 0);
+
+        /* Calculate APIC timer frequency based on ticks passed */
+        Frequency = (InitialCount - CurrentCount) * 100;
+
+        /* Verify APIC timer frequency */
+        if(Frequency == 0)
+        {
+            /* Unable to calibrate APIC timer, return error */
+            return STATUS_UNSUCCESSFUL;
+        }
+    }
+
+    /* Save APIC timer frequency */
+    TimerFrequency = Frequency;
+
+    /* Print APIC timer frequency and return success */
+    DebugPrint(L"APIC Timer calibrated: %u Ticks/s\n", TimerFrequency);
+    return STATUS_SUCCESS;
+}
+
+/**
+ * Retrieves the APIC timer frequency from the Core Crystal Clock.
+ *
+ * @param Frequency
+ *        Supplies a pointer to a variable that will receive the nominal APIC timer frequency in Hz.
+ *
+ * @return This routine returns a status code.
+ *
+ * @since XT 1.0
+ */
+XTAPI
+XTSTATUS
+HL::Timer::GetApicTimerFrequency(OUT PULONG Frequency)
+{
+    CPUID_REGISTERS CpuRegisters;
+
+    /* Verify input parameter */
+    if(!Frequency)
+    {
+        /* Invalid parameter passed */
+        return STATUS_INVALID_PARAMETER;
+    }
+
+    /* Initialize output parameter to 0 */
+    *Frequency = 0;
+
+    /* Get maximum supported standard CPUID leaf */
+    CpuRegisters.Leaf = 0;
+    CpuRegisters.SubLeaf = 0;
+    CpuRegisters.Eax = 0;
+    CpuRegisters.Ebx = 0;
+    CpuRegisters.Ecx = 0;
+    CpuRegisters.Edx = 0;
+    AR::CpuFunc::CpuId(&CpuRegisters);
+
+    /* Check if leaf 0x15 is supported by the CPU */
+    if(CpuRegisters.Eax < 0x15)
+    {
+        /* Processor is too old, return error */
+        return STATUS_NOT_SUPPORTED;
+    }
+
+    /* Query Time Stamp Counter and Core Crystal Clock information */
+    CpuRegisters.Leaf = 0x15;
+    CpuRegisters.SubLeaf = 0;
+    CpuRegisters.Eax = 0;
+    CpuRegisters.Ebx = 0;
+    CpuRegisters.Ecx = 0;
+    CpuRegisters.Edx = 0;
+    AR::CpuFunc::CpuId(&CpuRegisters);
+
+    /* Check if the leaf is properly enumerated */
+    if(CpuRegisters.Eax == 0 || CpuRegisters.Ebx == 0)
+    {
+        /* Intel SDM: EAX or EBX is 0, the leaf is not properly enumerated, return error */
+        return STATUS_NOT_SUPPORTED;
+    }
+
+    /* Check if ECX contains the nominal frequency of the core crystal clock */
+    if(CpuRegisters.Ecx == 0)
+    {
+        /* Hardware did not provide the exact frequency, return error */
+        return STATUS_NOT_FOUND;
+    }
+
+    /* Save the base frequency for the APIC Timer and return success */
+    *Frequency = CpuRegisters.Ecx;
+    return STATUS_SUCCESS;
+}
+
+/**
+ * Initializes and calibrates the Local APIC Timer.
+ *
+ * @return This routine does not return any value.
+ *
+ * @since XT 1.0
+ */
+XTAPI
+VOID
+HL::Timer::InitializeApicTimer(VOID)
+{
+    XTSTATUS Status;
+
+    /* Set APIC timer to divide by 1 */
+    HL::Pic::WriteApicRegister(APIC_TDCR, TIMER_DivideBy1);
+
+    /* Calibrate the APIC timer */
+    Status = CalibrateApicTimer();
+    if(Status != STATUS_SUCCESS)
+    {
+        /* System cannot operate without a calibrated system timer, raise kernel panic */
+        KE::Crash::Panic(0);
+    }
+
+    /* Set the default system profile interval */
+    HL::Timer::SetProfileInterval(1000);
+
+    /* Program the APIC timer for periodic mode */
+    StopProfileInterrupt(ProfileXtKernel);
+
+    // StartProfileInterrupt(ProfileXtKernel);
+    // AR::CpuFunc::SetInterruptFlag();
+}
+
+/**
+ * Stalls the CPU execution for a specified duration (maximum 3 seconds) using the legacy PIT timer.
+ *
+ * @param MicroSeconds
+ *        Specifies the number of microseconds to stall execution.
+ *
+ * @return This routine does not return any value.
+ *
+ * @since XT 1.0
+ */
+XTAPI
+VOID
+HL::Timer::PitStallExecution(IN ULONG MicroSeconds)
+{
+    USHORT CurrentCount, PreviousCount;
+    ULONG TargetTicks, TickCounter;
+
+    /* Validate input parameter */
+    if(MicroSeconds == 0)
+    {
+        /* Nothing to do */
+        return;
+    }
+    else if(MicroSeconds > 3000000)
+    {
+        /* Cap execution stall to 3 seconds */
+        MicroSeconds = 3000000;
+    }
+
+    /* Convert us to PIT ticks and initialize tick counter */
+    TargetTicks = (MicroSeconds * 1193) / 1000;
+    TickCounter = 0;
+
+    /* Configure PIT Channel 0: Read/Write LSB then MSB, Mode 0 (Interrupt on Terminal Count) */
+    HL::IoPort::WritePort8(PIT_COMMAND_PORT, 0x30);
+
+    /* Initialize the PIT counter with the maximum possible value (0xFFFF) */
+    HL::IoPort::WritePort8(PIT_DATA_PORT0, 0xFF);
+    HL::IoPort::WritePort8(PIT_DATA_PORT0, 0xFF);
+
+    /* Latch and read the initial counter value */
+    HL::IoPort::WritePort8(PIT_COMMAND_PORT, 0x00);
+    PreviousCount = HL::IoPort::ReadPort8(PIT_DATA_PORT0);
+    PreviousCount |= (HL::IoPort::ReadPort8(PIT_DATA_PORT0) << 8);
+
+    /* Poll the PIT */
+    while(TickCounter < TargetTicks)
+    {
+        /* Latch the current counter value without stopping the timer */
+        HL::IoPort::WritePort8(PIT_COMMAND_PORT, 0x00);
+        CurrentCount = HL::IoPort::ReadPort8(PIT_DATA_PORT0);
+        CurrentCount |= (HL::IoPort::ReadPort8(PIT_DATA_PORT0) << 8);
+
+        /* Calculate elapsed ticks since the last read */
+        TickCounter += (PreviousCount - CurrentCount) & 0xFFFF;
+
+        /* Update the tracking variable */
+        PreviousCount = CurrentCount;
+    }
+}
+
+/**
+ * Sets the profile interrupt interval. The interval may be bounded by hardware capabilities.
+ *
+ * @param Interval
+ *        Supplies the requested profile interval in 100-nanosecond units.
+ *
+ * @return This routine returns the actual profile interval that was set.
+ *
+ * @since XT 1.0
+ */
+XTAPI
+ULONG_PTR
+HL::Timer::SetProfileInterval(IN ULONG_PTR Interval)
+{
+    /* Validate and bound the requested profile interval against hardware limits */
+    if(Interval < MIN_PROFILE_INTERVAL)
+    {
+        /* Enforce the minimum profile interval limit */
+        Interval = MIN_PROFILE_INTERVAL;
+    }
+    else if(Interval > MAX_PROFILE_INTERVAL)
+    {
+        /* Enforce the maximum profile interval limit */
+        Interval = MAX_PROFILE_INTERVAL;
+    }
+
+    /* Calculate the number of APIC timer ticks required for the requested interval */
+    ProfilingInterval = (TimerFrequency / 10000) * (Interval / 1000);
+
+    /* Update the APIC Timer Initial Count Register (TICR) to apply the new interval immediately */
+    HL::Pic::WriteApicRegister(APIC_TICR, ProfilingInterval);
+
+    /* Return the actual interval */
+    return Interval;
+}
+
+/**
+ * Stalls the CPU execution for a specified duration.
+ *
+ * @param MicroSeconds
+ *        Supplies the number of microseconds to stall execution.
+ *
+ * @return This routine does not return any value.
+ *
+ * @since XT 1.0
+ */
+XTAPI
+VOID
+HL::Timer::StallExecution(IN ULONG MicroSeconds)
+{
+    UNIMPLEMENTED;
+
+    /* ACPI PM Timer not supported, fall back to PIT */
+    PitStallExecution(MicroSeconds);
+}
+
+/**
+ * Enables the profile interrupt for the specified profile source.
+ *
+ * @param ProfileSource
+ *        Supplies the source of the profile interrupt to start.
+ *
+ * @return This routine does not return any value.
+ *
+ * @since XT 1.0
+ */
+XTAPI
+VOID
+HL::Timer::StartProfileInterrupt(IN KPROFILE_SOURCE ProfileSource)
+{
+    APIC_LVT_REGISTER LvtRegister;
+
+    /* Handle only ProfileTime and ProfileXtKernel */
+    if(ProfileSource != ProfileTime && ProfileSource != ProfileXtKernel)
+    {
+        /* Invalid profile source, do nothing */
+        return;
+    }
+
+    /* Set the interval */
+    HL::Pic::WriteApicRegister(APIC_TICR, ProfilingInterval);
+
+    /* Unmask interrupt */
+    LvtRegister.Long = 0;
+    LvtRegister.Mask = 0;
+    LvtRegister.DeliveryMode = APIC_DM_FIXED;
+    LvtRegister.TimerMode = 1;
+    LvtRegister.TriggerMode = APIC_TGM_EDGE;
+    LvtRegister.Vector = APIC_VECTOR_PROFILE;
+    HL::Pic::WriteApicRegister(APIC_TMRLVTR, LvtRegister.Long);
+}
+
+/**
+ * Disables the profile interrupt for the specified profile source.
+ *
+ * @param ProfileSource
+ *        Supplies the source of the profile interrupt to stop.
+ *
+ * @return This routine does not return any value.
+ *
+ * @since XT 1.0
+ */
+XTAPI
+VOID
+HL::Timer::StopProfileInterrupt(IN KPROFILE_SOURCE ProfileSource)
+{
+    APIC_LVT_REGISTER LvtRegister;
+
+    /* Handle only ProfileTime and ProfileXtKernel */
+    if(ProfileSource != ProfileTime && ProfileSource != ProfileXtKernel)
+    {
+        /* Invalid profile source, do nothing */
+        return;
+    }
+
+    /* Mask interrupt */
+    LvtRegister.Long = 0;
+    LvtRegister.Mask = 1;
+    LvtRegister.DeliveryMode = APIC_DM_FIXED;
+    LvtRegister.TimerMode = 1;
+    LvtRegister.TriggerMode = APIC_TGM_EDGE;
+    LvtRegister.Vector = APIC_VECTOR_PROFILE;
+    HL::Pic::WriteApicRegister(APIC_TMRLVTR, LvtRegister.Long);
+}

xtoskrnl/includes/hl.hh

@@ -21,6 +21,7 @@
 #include <hl/irq.hh>
 #include <hl/pic.hh>
 #include <hl/runlevel.hh>
+#include <hl/timer.hh>
 
 
 #endif /* __XTOSKRNL_HL_HH */

xtoskrnl/includes/hl/timer.hh

@@ -0,0 +1,38 @@
+/**
+ * PROJECT:         ExectOS
+ * COPYRIGHT:       See COPYING.md in the top level directory
+ * FILE:            xtoskrnl/includes/hl/timer.hh
+ * DESCRIPTION:     ACPI Timer support
+ * DEVELOPERS:      Aiken Harris <harraiken91@gmail.com>
+ */
+
+#ifndef __XTOSKRNL_HL_TIMER_HH
+#define __XTOSKRNL_HL_TIMER_HH
+
+#include <xtos.hh>
+
+
+/* Hardware Layer */
+namespace HL
+{
+    class Timer
+    {
+        private:
+            STATIC ULONG ProfilingInterval;
+            STATIC ULONG TimerFrequency;
+
+        public:
+            STATIC XTAPI VOID InitializeApicTimer(VOID);
+            STATIC XTAPI ULONG_PTR SetProfileInterval(IN ULONG_PTR Interval);
+            STATIC XTAPI VOID StartProfileInterrupt(IN KPROFILE_SOURCE ProfileSource);
+            STATIC XTAPI VOID StopProfileInterrupt(IN KPROFILE_SOURCE ProfileSource);
+
+        private:
+            STATIC XTAPI XTSTATUS CalibrateApicTimer();
+            STATIC XTAPI XTSTATUS GetApicTimerFrequency(OUT PULONG Frequency);
+            STATIC XTAPI VOID PitStallExecution(IN ULONG Us);
+            STATIC XTAPI VOID StallExecution(IN ULONG MicroSeconds);
+    };
+}
+
+#endif /* __XTOSKRNL_HL_TIMER_HH */