// SPDX-License-Identifier: GPL-2.0-only
#include <linux/cpumask.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/msi.h>
#include <linux/irq.h>
#include <linux/pci.h>
#include <linux/irqdomain.h>

#include <asm/hw_irq.h>
#include <asm/irq_remapping.h>
#include <asm/processor.h>
#include <asm/x86_init.h>
#include <asm/apic.h>
#include <asm/hpet.h>

#include "irq_remapping.h"

int irq_remapping_enabled;
int irq_remap_broken;
int disable_sourceid_checking;
int no_x2apic_optout;

int disable_irq_post = 0;

bool enable_posted_msi __ro_after_init;

static int disable_irq_remap;
static struct irq_remap_ops *remap_ops;

static void irq_remapping_restore_boot_irq_mode(void)
{
        /*
         * With interrupt-remapping, for now we will use virtual wire A
         * mode, as virtual wire B is little complex (need to configure
         * both IOAPIC RTE as well as interrupt-remapping table entry).
         * As this gets called during crash dump, keep this simple for
         * now.
         */
        if (boot_cpu_has(X86_FEATURE_APIC) || apic_from_smp_config())
                disconnect_bsp_APIC(0);
}

static void __init irq_remapping_modify_x86_ops(void)
{
        x86_apic_ops.restore = irq_remapping_restore_boot_irq_mode;
}

static __init int setup_nointremap(char *str)
{
        disable_irq_remap = 1;
        return 0;
}
early_param("nointremap", setup_nointremap);

static __init int setup_irqremap(char *str)
{
        if (!str)
                return -EINVAL;

        while (*str) {
                if (!strncmp(str, "on", 2)) {
                        disable_irq_remap = 0;
                        disable_irq_post = 0;
                } else if (!strncmp(str, "off", 3)) {
                        disable_irq_remap = 1;
                        disable_irq_post = 1;
                } else if (!strncmp(str, "nosid", 5))
                        disable_sourceid_checking = 1;
                else if (!strncmp(str, "no_x2apic_optout", 16))
                        no_x2apic_optout = 1;
                else if (!strncmp(str, "nopost", 6))
                        disable_irq_post = 1;
                else if (IS_ENABLED(CONFIG_X86_POSTED_MSI) && !strncmp(str, "posted_msi", 10))
                        enable_posted_msi = true;
                str += strcspn(str, ",");
                while (*str == ',')
                        str++;
        }

        return 0;
}
early_param("intremap", setup_irqremap);

void set_irq_remapping_broken(void)
{
        irq_remap_broken = 1;
}

bool irq_remapping_cap(enum irq_remap_cap cap)
{
        if (!remap_ops || disable_irq_post)
                return false;

        return (remap_ops->capability & (1 << cap));
}
EXPORT_SYMBOL_GPL(irq_remapping_cap);

int __init irq_remapping_prepare(void)
{
        if (disable_irq_remap)
                return -ENOSYS;

        if (IS_ENABLED(CONFIG_INTEL_IOMMU) &&
            intel_irq_remap_ops.prepare() == 0)
                remap_ops = &intel_irq_remap_ops;
        else if (IS_ENABLED(CONFIG_AMD_IOMMU) &&
                 amd_iommu_irq_ops.prepare() == 0)
                remap_ops = &amd_iommu_irq_ops;
        else if (IS_ENABLED(CONFIG_HYPERV_IOMMU) &&
                 hyperv_irq_remap_ops.prepare() == 0)
                remap_ops = &hyperv_irq_remap_ops;
        else
                return -ENOSYS;

        return 0;
}

int __init irq_remapping_enable(void)
{
        int ret;

        if (!remap_ops->enable)
                return -ENODEV;

        ret = remap_ops->enable();

        if (irq_remapping_enabled)
                irq_remapping_modify_x86_ops();

        return ret;
}

void irq_remapping_disable(void)
{
        if (irq_remapping_enabled && remap_ops->disable)
                remap_ops->disable();
}

int irq_remapping_reenable(int mode)
{
        if (irq_remapping_enabled && remap_ops->reenable)
                return remap_ops->reenable(mode);

        return 0;
}

int __init irq_remap_enable_fault_handling(void)
{
        if (!irq_remapping_enabled)
                return 0;

        if (!remap_ops->enable_faulting)
                return -ENODEV;

        cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "dmar:enable_fault_handling",
                          remap_ops->enable_faulting, NULL);

        return remap_ops->enable_faulting(smp_processor_id());
}

void panic_if_irq_remap(const char *msg)
{
        if (irq_remapping_enabled)
                panic(msg);
}