/*
 * Copyright 2010-2011, Michael Lotz, mmlr@mlotz.ch. All Rights Reserved.
 * Distributed under the terms of the MIT license.
 */

#include <arch/x86/apic.h>
#include <arch/x86/msi.h>
#include <arch/x86/arch_smp.h>

#include <debug.h>
#include <interrupts.h>
#include <lock.h>


struct MSIConfiguration {
        uint64* fAddress;
        uint32* fData;
};

static MSIConfiguration sMSIConfigurations[NUM_IO_VECTORS];

static bool sMSISupported = false;
static uint32 sBootCPUAPICId = 0;


void
msi_init(kernel_args* args)
{
        if (!apic_available()) {
                dprintf("disabling msi due to missing apic\n");
                return;
        }

        dprintf("msi support enabled\n");
        sMSISupported = true;
        sBootCPUAPICId = args->arch_args.cpu_apic_id[0];
}


bool
msi_supported()
{
        return sMSISupported;
}


status_t
msi_allocate_vectors(uint32 count, uint32 *startVector, uint64 *address,
        uint32 *data)
{
        if (!sMSISupported)
                return B_UNSUPPORTED;

        int32 vector;
        status_t result = allocate_io_interrupt_vectors(count, &vector,
                INTERRUPT_TYPE_IRQ);
        if (result != B_OK)
                return result;

        if (vector >= NUM_IO_VECTORS) {
                free_io_interrupt_vectors(count, vector);
                return B_NO_MEMORY;
        }

        sMSIConfigurations[vector].fAddress = address;
        sMSIConfigurations[vector].fData = data;
        x86_set_irq_source(vector, IRQ_SOURCE_MSI);

        *startVector = (uint32)vector;
        *address = MSI_ADDRESS_BASE | (sBootCPUAPICId << MSI_DESTINATION_ID_SHIFT)
                | MSI_NO_REDIRECTION | MSI_DESTINATION_MODE_PHYSICAL;
        *data = MSI_TRIGGER_MODE_EDGE | MSI_DELIVERY_MODE_FIXED
                | ((uint16)vector + ARCH_INTERRUPT_BASE);

        dprintf("msi_allocate_vectors: allocated %" B_PRIu32 " vectors starting from %" B_PRIu32 "\n",
                count, *startVector);
        return B_OK;
}


void
msi_free_vectors(uint32 count, uint32 startVector)
{
        if (!sMSISupported) {
                panic("trying to free msi vectors but msi not supported\n");
                return;
        }

        dprintf("msi_free_vectors: freeing %" B_PRIu32 " vectors starting from %" B_PRIu32 "\n", count,
                startVector);

        free_io_interrupt_vectors(count, startVector);
}


void
msi_assign_interrupt_to_cpu(uint32 irq, int32 cpu)
{
        uint32 apic_id = x86_get_cpu_apic_id(cpu);

        uint64* address = sMSIConfigurations[irq].fAddress;
        *address = MSI_ADDRESS_BASE | (apic_id << MSI_DESTINATION_ID_SHIFT)
                | MSI_NO_REDIRECTION | MSI_DESTINATION_MODE_PHYSICAL;
}