/**
 * PROJECT:         ExectOS
 * COPYRIGHT:       See COPYING.md in the top level directory
 * FILE:            xtoskrnl/hl/x86/cpu.c
 * DESCRIPTION:     HAL x86 (i686/AMD64) processor support
 * DEVELOPERS:      Rafal Kupiec <belliash@codingworkshop.eu.org>
 */

#include <xtos.h>


/**
 * Initializes the processor.
 *
 * @param CpuNumber
 *        Supplies the number of the CPU, that is being initialized.
 *
 * @return This routine does not return any value.
 *
 * @since XT 1.0
 */
XTAPI
VOID
HlInitializeProcessor(VOID)
{
    PKPROCESSOR_BLOCK ProcessorBlock;
    KAFFINITY Affinity;

    /* Get current processor block */
    ProcessorBlock = KeGetCurrentProcessorBlock();

    /* Set initial stall factor, CPU number and mask interrupts */
    ProcessorBlock->StallScaleFactor = INITIAL_STALL_FACTOR;
    ProcessorBlock->Idr = 0xFFFFFFFF;

    /* Set processor affinity */
    Affinity = (KAFFINITY) 1 << ProcessorBlock->CpuNumber;

    /* Apply affinity to a set of processors */
    HlpActiveProcessors |= Affinity;

    /* Initialize APIC for this processor */
    HlpInitializePic();

    /* Set the APIC running level */
    HlSetRunLevel(KeGetCurrentProcessorBlock()->RunLevel);
}

XTAPI
XTSTATUS
HlStartProcessor(IN ULONG CpuId,
                 IN PHYSICAL_ADDRESS EntryPoint)
{
    UCHAR Attempt;

    /* Wait until command register is clear */
    while((HlReadApicRegister(APIC_ICR0) & APIC_DELIVERY_PENDING) != 0);

    /* Trigger INIT IPI and wait for delivery bit to be cleared */
    HlpSendIpi(CpuId, APIC_DM_INIT | APIC_DM_LEVEL | APIC_DM_ASSERT);
    while((HlReadApicRegister(APIC_ICR0) & APIC_DELIVERY_PENDING) != 0);

    /* Deassert INIT IPI to take CPU out of reset and wait for delivery bit to be cleared */
    HlpSendIpi(CpuId, APIC_DM_INIT | APIC_DM_LEVEL);
    while((HlReadApicRegister(APIC_ICR0) & APIC_DELIVERY_PENDING) != 0);

    /* Two attempts to send STARTUP IPI */
    for(Attempt = 0; Attempt < 2; Attempt++)
    {
        /* Trigger STARTUP IPI and wait for delivery bit to be cleared */
        HlpSendIpi(CpuId, APIC_DM_STARTUP | (EntryPoint.LowPart >> 12));
        while((HlReadApicRegister(APIC_ICR0) & APIC_DELIVERY_PENDING) != 0);
    }

    /* Memory barrier */
    ArMemoryBarrier();

    /* Return success */
    return STATUS_SUCCESS;
}

XTAPI
XTSTATUS
HlStartAllProcessors(VOID)
{
    PHYSICAL_ADDRESS ApPhysicalAddress;
    PVOID ApVirtualAddress;
    BOOLEAN Interrupts;
    XTSTATUS Status;
    USHORT Cpu;

/* Temp bootstrap code size */
#define AP_SPINUP_PAGE_COUNT 5

    /* Check if at least one AP is present */
    if(HlpSystemInfo.CpuCount > 1)
    {
        /* Allocate 5 pages for AP bootstrap code and ensure it is low memory */
        Status = MmAllocateHardwareMemory(AP_SPINUP_PAGE_COUNT, FALSE, &ApPhysicalAddress);
        if(Status != STATUS_SUCCESS || ApPhysicalAddress.QuadPart > (0x100000 - AP_SPINUP_PAGE_COUNT * MM_PAGE_SIZE))
        {
            /* Not enough free pages at low memory available, return error */
            return STATUS_INSUFFICIENT_RESOURCES;
        }

        /* Map AP bootstrap code */
        Status = MmMapHardwareMemory(ApPhysicalAddress, AP_SPINUP_PAGE_COUNT, TRUE, &ApVirtualAddress);
        if(Status != STATUS_SUCCESS)
        {
            /* Failed to map AP bootstrap code, return error */
            return STATUS_INSUFFICIENT_RESOURCES;
        }

        /* Copy AP bootstrap code into low memory */
        RtlCopyMemory(ApVirtualAddress, &ArStartApplicationProcessor, AP_SPINUP_PAGE_COUNT * MM_PAGE_SIZE);

        /* Iterate over all CPUs and start them */
        for(Cpu = 0; Cpu < HlpSystemInfo.CpuCount; Cpu++)
        {
            /* Check if this CPU is the BSP */
            if(HlpSystemInfo.CpuInfo[Cpu].ApicId == HlpGetCpuApicId())
            {
                /* This is the BSP, set proper flag and mark as started */
                HlpSystemInfo.CpuInfo[Cpu].Bsp = TRUE;
                HlpSystemInfo.CpuInfo[Cpu].Started = TRUE;

                /* Continue with next CPU */
                continue;
            }

            /* Temp debugging */
            DebugPrint(L"Starting CPU #%lu (ACPI ID: %u, APIC ID: %u)\n", Cpu, HlpSystemInfo.CpuInfo[Cpu].AcpiId, HlpSystemInfo.CpuInfo[Cpu].ApicId);

            /* Check if interrupts are enabled and disable them */
            Interrupts = ArInterruptsEnabled();
            ArClearInterruptFlag();

            /* Start the AP */
            Status = HlStartProcessor(HlpSystemInfo.CpuInfo[Cpu].ApicId, ApPhysicalAddress);
            if(Status == STATUS_SUCCESS)
            {
                /* Mark AP as started */
                HlpSystemInfo.CpuInfo[Cpu].Started = TRUE;
            }

            /* Check if interrupts were originally enabled */
            if(Interrupts)
            {
                /* Re-enable interrupts */
                ArSetInterruptFlag();
            }
        }

        /* Unmap AP bootstrap code */
        MmUnmapHardwareMemory(ApVirtualAddress, AP_SPINUP_PAGE_COUNT, TRUE);
    }

    /* Return success */
    return STATUS_SUCCESS;
}