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

#include "irq_remapping.h"

int irq_remapping_enabled;

int disable_irq_remap;
int irq_remap_broken;
int disable_sourceid_checking;
int no_x2apic_optout;

static struct irq_remap_ops *remap_ops;

static int msi_alloc_remapped_irq(struct pci_dev *pdev, int irq, int nvec);
static int msi_setup_remapped_irq(struct pci_dev *pdev, unsigned int irq,
                                  int index, int sub_handle);
static int set_remapped_irq_affinity(struct irq_data *data,
                                     const struct cpumask *mask,
                                     bool force);

static bool irq_remapped(struct irq_cfg *cfg)
{
        return (cfg->remapped == 1);
}

static void irq_remapping_disable_io_apic(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 (cpu_has_apic || apic_from_smp_config())
                disconnect_bsp_APIC(0);
}

static int do_setup_msi_irqs(struct pci_dev *dev, int nvec)
{
        int node, ret, sub_handle, nvec_pow2, index = 0;
        unsigned int irq;
        struct msi_desc *msidesc;

        WARN_ON(!list_is_singular(&dev->msi_list));
        msidesc = list_entry(dev->msi_list.next, struct msi_desc, list);
        WARN_ON(msidesc->irq);
        WARN_ON(msidesc->msi_attrib.multiple);
        WARN_ON(msidesc->nvec_used);

        node = dev_to_node(&dev->dev);
        irq = __create_irqs(get_nr_irqs_gsi(), nvec, node);
        if (irq == 0)
                return -ENOSPC;

        nvec_pow2 = __roundup_pow_of_two(nvec);
        msidesc->nvec_used = nvec;
        msidesc->msi_attrib.multiple = ilog2(nvec_pow2);
        for (sub_handle = 0; sub_handle < nvec; sub_handle++) {
                if (!sub_handle) {
                        index = msi_alloc_remapped_irq(dev, irq, nvec_pow2);
                        if (index < 0) {
                                ret = index;
                                goto error;
                        }
                } else {
                        ret = msi_setup_remapped_irq(dev, irq + sub_handle,
                                                     index, sub_handle);
                        if (ret < 0)
                                goto error;
                }
                ret = setup_msi_irq(dev, msidesc, irq, sub_handle);
                if (ret < 0)
                        goto error;
        }
        return 0;

error:
        destroy_irqs(irq, nvec);

        /*
         * Restore altered MSI descriptor fields and prevent just destroyed
         * IRQs from tearing down again in default_teardown_msi_irqs()
         */
        msidesc->irq = 0;
        msidesc->nvec_used = 0;
        msidesc->msi_attrib.multiple = 0;

        return ret;
}

static int do_setup_msix_irqs(struct pci_dev *dev, int nvec)
{
        int node, ret, sub_handle, index = 0;
        struct msi_desc *msidesc;
        unsigned int irq;

        node            = dev_to_node(&dev->dev);
        irq             = get_nr_irqs_gsi();
        sub_handle      = 0;

        list_for_each_entry(msidesc, &dev->msi_list, list) {

                irq = create_irq_nr(irq, node);
                if (irq == 0)
                        return -1;

                if (sub_handle == 0)
                        ret = index = msi_alloc_remapped_irq(dev, irq, nvec);
                else
                        ret = msi_setup_remapped_irq(dev, irq, index, sub_handle);

                if (ret < 0)
                        goto error;

                ret = setup_msi_irq(dev, msidesc, irq, 0);
                if (ret < 0)
                        goto error;

                sub_handle += 1;
                irq        += 1;
        }

        return 0;

error:
        destroy_irq(irq);
        return ret;
}

static int irq_remapping_setup_msi_irqs(struct pci_dev *dev,
                                        int nvec, int type)
{
        if (type == PCI_CAP_ID_MSI)
                return do_setup_msi_irqs(dev, nvec);
        else
                return do_setup_msix_irqs(dev, nvec);
}

void eoi_ioapic_pin_remapped(int apic, int pin, int vector)
{
        /*
         * Intr-remapping uses pin number as the virtual vector
         * in the RTE. Actual vector is programmed in
         * intr-remapping table entry. Hence for the io-apic
         * EOI we use the pin number.
         */
        io_apic_eoi(apic, pin);
}

static void __init irq_remapping_modify_x86_ops(void)
{
        x86_io_apic_ops.disable         = irq_remapping_disable_io_apic;
        x86_io_apic_ops.set_affinity    = set_remapped_irq_affinity;
        x86_io_apic_ops.setup_entry     = setup_ioapic_remapped_entry;
        x86_io_apic_ops.eoi_ioapic_pin  = eoi_ioapic_pin_remapped;
        x86_msi.setup_msi_irqs          = irq_remapping_setup_msi_irqs;
        x86_msi.setup_hpet_msi          = setup_hpet_msi_remapped;
        x86_msi.compose_msi_msg         = compose_remapped_msi_msg;
}

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;
                else if (!strncmp(str, "off", 3))
                        disable_irq_remap = 1;
                else if (!strncmp(str, "nosid", 5))
                        disable_sourceid_checking = 1;
                else if (!strncmp(str, "no_x2apic_optout", 16))
                        no_x2apic_optout = 1;

                str += strcspn(str, ",");
                while (*str == ',')
                        str++;
        }

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

void __init setup_irq_remapping_ops(void)
{
        remap_ops = &intel_irq_remap_ops;

#ifdef CONFIG_AMD_IOMMU
        if (amd_iommu_irq_ops.prepare() == 0)
                remap_ops = &amd_iommu_irq_ops;
#endif
}

void set_irq_remapping_broken(void)
{
        irq_remap_broken = 1;
}

int irq_remapping_supported(void)
{
        if (disable_irq_remap)
                return 0;

        if (!remap_ops || !remap_ops->supported)
                return 0;

        return remap_ops->supported();
}

int __init irq_remapping_prepare(void)
{
        if (!remap_ops || !remap_ops->prepare)
                return -ENODEV;

        return remap_ops->prepare();
}

int __init irq_remapping_enable(void)
{
        int ret;

        if (!remap_ops || !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 ||
            !remap_ops->disable)
                return;

        remap_ops->disable();
}

int irq_remapping_reenable(int mode)
{
        if (!irq_remapping_enabled ||
            !remap_ops ||
            !remap_ops->reenable)
                return 0;

        return remap_ops->reenable(mode);
}

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

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

        return remap_ops->enable_faulting();
}

int setup_ioapic_remapped_entry(int irq,
                                struct IO_APIC_route_entry *entry,
                                unsigned int destination, int vector,
                                struct io_apic_irq_attr *attr)
{
        if (!remap_ops || !remap_ops->setup_ioapic_entry)
                return -ENODEV;

        return remap_ops->setup_ioapic_entry(irq, entry, destination,
                                             vector, attr);
}

int set_remapped_irq_affinity(struct irq_data *data, const struct cpumask *mask,
                              bool force)
{
        if (!config_enabled(CONFIG_SMP) || !remap_ops ||
            !remap_ops->set_affinity)
                return 0;

        return remap_ops->set_affinity(data, mask, force);
}

void free_remapped_irq(int irq)
{
        struct irq_cfg *cfg = irq_get_chip_data(irq);

        if (!remap_ops || !remap_ops->free_irq)
                return;

        if (irq_remapped(cfg))
                remap_ops->free_irq(irq);
}

void compose_remapped_msi_msg(struct pci_dev *pdev,
                              unsigned int irq, unsigned int dest,
                              struct msi_msg *msg, u8 hpet_id)
{
        struct irq_cfg *cfg = irq_get_chip_data(irq);

        if (!irq_remapped(cfg))
                native_compose_msi_msg(pdev, irq, dest, msg, hpet_id);
        else if (remap_ops && remap_ops->compose_msi_msg)
                remap_ops->compose_msi_msg(pdev, irq, dest, msg, hpet_id);
}

static int msi_alloc_remapped_irq(struct pci_dev *pdev, int irq, int nvec)
{
        if (!remap_ops || !remap_ops->msi_alloc_irq)
                return -ENODEV;

        return remap_ops->msi_alloc_irq(pdev, irq, nvec);
}

static int msi_setup_remapped_irq(struct pci_dev *pdev, unsigned int irq,
                                  int index, int sub_handle)
{
        if (!remap_ops || !remap_ops->msi_setup_irq)
                return -ENODEV;

        return remap_ops->msi_setup_irq(pdev, irq, index, sub_handle);
}

int setup_hpet_msi_remapped(unsigned int irq, unsigned int id)
{
        if (!remap_ops || !remap_ops->setup_hpet_msi)
                return -ENODEV;

        return remap_ops->setup_hpet_msi(irq, id);
}

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

static void ir_ack_apic_edge(struct irq_data *data)
{
        ack_APIC_irq();
}

static void ir_ack_apic_level(struct irq_data *data)
{
        ack_APIC_irq();
        eoi_ioapic_irq(data->irq, data->chip_data);
}

static void ir_print_prefix(struct irq_data *data, struct seq_file *p)
{
        seq_printf(p, " IR-%s", data->chip->name);
}

void irq_remap_modify_chip_defaults(struct irq_chip *chip)
{
        chip->irq_print_chip = ir_print_prefix;
        chip->irq_ack = ir_ack_apic_edge;
        chip->irq_eoi = ir_ack_apic_level;
        chip->irq_set_affinity = x86_io_apic_ops.set_affinity;
}

bool setup_remapped_irq(int irq, struct irq_cfg *cfg, struct irq_chip *chip)
{
        if (!irq_remapped(cfg))
                return false;
        irq_set_status_flags(irq, IRQ_MOVE_PCNTXT);
        irq_remap_modify_chip_defaults(chip);
        return true;
}