// SPDX-License-Identifier: GPL-2.0-only
/*
 * Support of MSI, HPET and DMAR interrupts.
 *
 * Copyright (C) 1997, 1998, 1999, 2000, 2009 Ingo Molnar, Hajnalka Szabo
 *      Moved from arch/x86/kernel/apic/io_apic.c.
 * Jiang Liu <jiang.liu@linux.intel.com>
 *      Convert to hierarchical irqdomain
 */
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/pci.h>
#include <linux/dmar.h>
#include <linux/hpet.h>
#include <linux/msi.h>
#include <asm/irqdomain.h>
#include <asm/hpet.h>
#include <asm/hw_irq.h>
#include <asm/apic.h>
#include <asm/irq_remapping.h>
#include <asm/xen/hypervisor.h>

struct irq_domain *x86_pci_msi_default_domain __ro_after_init;

static void irq_msi_update_msg(struct irq_data *irqd, struct irq_cfg *cfg)
{
        struct msi_msg msg[2] = { [1] = { }, };

        __irq_msi_compose_msg(cfg, msg, false);
        irq_data_get_irq_chip(irqd)->irq_write_msi_msg(irqd, msg);
}

static int
msi_set_affinity(struct irq_data *irqd, const struct cpumask *mask, bool force)
{
        struct irq_cfg old_cfg, *cfg = irqd_cfg(irqd);
        struct irq_data *parent = irqd->parent_data;
        unsigned int cpu;
        int ret;

        /* Save the current configuration */
        cpu = cpumask_first(irq_data_get_effective_affinity_mask(irqd));
        old_cfg = *cfg;

        /* Allocate a new target vector */
        ret = parent->chip->irq_set_affinity(parent, mask, force);
        if (ret < 0 || ret == IRQ_SET_MASK_OK_DONE)
                return ret;

        /*
         * For non-maskable and non-remapped MSI interrupts the migration
         * to a different destination CPU and a different vector has to be
         * done careful to handle the possible stray interrupt which can be
         * caused by the non-atomic update of the address/data pair.
         *
         * Direct update is possible when:
         * - The MSI is maskable (remapped MSI does not use this code path).
         *   The reservation mode bit is set in this case.
         * - The new vector is the same as the old vector
         * - The old vector is MANAGED_IRQ_SHUTDOWN_VECTOR (interrupt starts up)
         * - The interrupt is not yet started up
         * - The new destination CPU is the same as the old destination CPU
         */
        if (!irqd_can_reserve(irqd) ||
            cfg->vector == old_cfg.vector ||
            old_cfg.vector == MANAGED_IRQ_SHUTDOWN_VECTOR ||
            !irqd_is_started(irqd) ||
            cfg->dest_apicid == old_cfg.dest_apicid) {
                irq_msi_update_msg(irqd, cfg);
                return ret;
        }

        /*
         * Paranoia: Validate that the interrupt target is the local
         * CPU.
         */
        if (WARN_ON_ONCE(cpu != smp_processor_id())) {
                irq_msi_update_msg(irqd, cfg);
                return ret;
        }

        /*
         * Redirect the interrupt to the new vector on the current CPU
         * first. This might cause a spurious interrupt on this vector if
         * the device raises an interrupt right between this update and the
         * update to the final destination CPU.
         *
         * If the vector is in use then the installed device handler will
         * denote it as spurious which is no harm as this is a rare event
         * and interrupt handlers have to cope with spurious interrupts
         * anyway. If the vector is unused, then it is marked so it won't
         * trigger the 'No irq handler for vector' warning in
         * common_interrupt().
         *
         * This requires to hold vector lock to prevent concurrent updates to
         * the affected vector.
         */
        lock_vector_lock();

        /*
         * Mark the new target vector on the local CPU if it is currently
         * unused. Reuse the VECTOR_RETRIGGERED state which is also used in
         * the CPU hotplug path for a similar purpose. This cannot be
         * undone here as the current CPU has interrupts disabled and
         * cannot handle the interrupt before the whole set_affinity()
         * section is done. In the CPU unplug case, the current CPU is
         * about to vanish and will not handle any interrupts anymore. The
         * vector is cleaned up when the CPU comes online again.
         */
        if (IS_ERR_OR_NULL(this_cpu_read(vector_irq[cfg->vector])))
                this_cpu_write(vector_irq[cfg->vector], VECTOR_RETRIGGERED);

        /* Redirect it to the new vector on the local CPU temporarily */
        old_cfg.vector = cfg->vector;
        irq_msi_update_msg(irqd, &old_cfg);

        /* Now transition it to the target CPU */
        irq_msi_update_msg(irqd, cfg);

        /*
         * All interrupts after this point are now targeted at the new
         * vector/CPU.
         *
         * Drop vector lock before testing whether the temporary assignment
         * to the local CPU was hit by an interrupt raised in the device,
         * because the retrigger function acquires vector lock again.
         */
        unlock_vector_lock();

        /*
         * Check whether the transition raced with a device interrupt and
         * is pending in the local APICs IRR. It is safe to do this outside
         * of vector lock as the irq_desc::lock of this interrupt is still
         * held and interrupts are disabled: The check is not accessing the
         * underlying vector store. It's just checking the local APIC's
         * IRR.
         */
        if (lapic_vector_set_in_irr(cfg->vector))
                irq_data_get_irq_chip(irqd)->irq_retrigger(irqd);

        return ret;
}

/**
 * pci_dev_has_default_msi_parent_domain - Check whether the device has the default
 *                                         MSI parent domain associated
 * @dev:        Pointer to the PCI device
 */
bool pci_dev_has_default_msi_parent_domain(struct pci_dev *dev)
{
        struct irq_domain *domain = dev_get_msi_domain(&dev->dev);

        if (!domain)
                domain = dev_get_msi_domain(&dev->bus->dev);
        if (!domain)
                return false;

        return domain == x86_vector_domain;
}

/**
 * x86_msi_prepare - Setup of msi_alloc_info_t for allocations
 * @domain:     The domain for which this setup happens
 * @dev:        The device for which interrupts are allocated
 * @nvec:       The number of vectors to allocate
 * @alloc:      The allocation info structure to initialize
 *
 * This function is to be used for all types of MSI domains above the x86
 * vector domain and any intermediates. It is always invoked from the
 * top level interrupt domain. The domain specific allocation
 * functionality is determined via the @domain's bus token which allows to
 * map the X86 specific allocation type.
 */
static int x86_msi_prepare(struct irq_domain *domain, struct device *dev,
                           int nvec, msi_alloc_info_t *alloc)
{
        struct msi_domain_info *info = domain->host_data;

        init_irq_alloc_info(alloc, NULL);

        switch (info->bus_token) {
        case DOMAIN_BUS_PCI_DEVICE_MSI:
                alloc->type = X86_IRQ_ALLOC_TYPE_PCI_MSI;
                return 0;
        case DOMAIN_BUS_PCI_DEVICE_MSIX:
                alloc->type = X86_IRQ_ALLOC_TYPE_PCI_MSIX;
                return 0;
        default:
                return -EINVAL;
        }
}

/**
 * x86_init_dev_msi_info - Domain info setup for MSI domains
 * @dev:                The device for which the domain should be created
 * @domain:             The (root) domain providing this callback
 * @real_parent:        The real parent domain of the to initialize domain
 * @info:               The domain info for the to initialize domain
 *
 * This function is to be used for all types of MSI domains above the x86
 * vector domain and any intermediates. The domain specific functionality
 * is determined via the @real_parent.
 */
static bool x86_init_dev_msi_info(struct device *dev, struct irq_domain *domain,
                                  struct irq_domain *real_parent, struct msi_domain_info *info)
{
        const struct msi_parent_ops *pops = real_parent->msi_parent_ops;

        /* MSI parent domain specific settings */
        switch (real_parent->bus_token) {
        case DOMAIN_BUS_ANY:
                /* Only the vector domain can have the ANY token */
                if (WARN_ON_ONCE(domain != real_parent))
                        return false;
                info->chip->irq_set_affinity = msi_set_affinity;
                info->chip->flags |= IRQCHIP_MOVE_DEFERRED;
                break;
        case DOMAIN_BUS_DMAR:
        case DOMAIN_BUS_AMDVI:
                break;
        default:
                WARN_ON_ONCE(1);
                return false;
        }

        /* Is the target supported? */
        switch(info->bus_token) {
        case DOMAIN_BUS_PCI_DEVICE_MSI:
        case DOMAIN_BUS_PCI_DEVICE_MSIX:
                break;
        default:
                WARN_ON_ONCE(1);
                return false;
        }

        /*
         * Mask out the domain specific MSI feature flags which are not
         * supported by the real parent.
         */
        info->flags                     &= pops->supported_flags;
        /* Enforce the required flags */
        info->flags                     |= X86_VECTOR_MSI_FLAGS_REQUIRED;

        /* This is always invoked from the top level MSI domain! */
        info->ops->msi_prepare          = x86_msi_prepare;

        info->chip->irq_ack             = irq_chip_ack_parent;
        info->chip->irq_retrigger       = irq_chip_retrigger_hierarchy;
        info->chip->flags               |= IRQCHIP_SKIP_SET_WAKE |
                                           IRQCHIP_AFFINITY_PRE_STARTUP;

        info->handler                   = handle_edge_irq;
        info->handler_name              = "edge";

        return true;
}

static const struct msi_parent_ops x86_vector_msi_parent_ops = {
        .supported_flags        = X86_VECTOR_MSI_FLAGS_SUPPORTED,
        .init_dev_msi_info      = x86_init_dev_msi_info,
};

struct irq_domain * __init native_create_pci_msi_domain(void)
{
        if (apic_is_disabled)
                return NULL;

        x86_vector_domain->flags |= IRQ_DOMAIN_FLAG_MSI_PARENT;
        x86_vector_domain->msi_parent_ops = &x86_vector_msi_parent_ops;
        return x86_vector_domain;
}

void __init x86_create_pci_msi_domain(void)
{
        x86_pci_msi_default_domain = x86_init.irqs.create_pci_msi_domain();
}

/* Keep around for hyperV */
int pci_msi_prepare(struct irq_domain *domain, struct device *dev, int nvec,
                    msi_alloc_info_t *arg)
{
        init_irq_alloc_info(arg, NULL);

        if (to_pci_dev(dev)->msix_enabled)
                arg->type = X86_IRQ_ALLOC_TYPE_PCI_MSIX;
        else
                arg->type = X86_IRQ_ALLOC_TYPE_PCI_MSI;
        return 0;
}
EXPORT_SYMBOL_GPL(pci_msi_prepare);

#ifdef CONFIG_DMAR_TABLE
/*
 * The Intel IOMMU (ab)uses the high bits of the MSI address to contain the
 * high bits of the destination APIC ID. This can't be done in the general
 * case for MSIs as it would be targeting real memory above 4GiB not the
 * APIC.
 */
static void dmar_msi_compose_msg(struct irq_data *data, struct msi_msg *msg)
{
        __irq_msi_compose_msg(irqd_cfg(data), msg, true);
}

static void dmar_msi_write_msg(struct irq_data *data, struct msi_msg *msg)
{
        dmar_msi_write(data->irq, msg);
}

static struct irq_chip dmar_msi_controller = {
        .name                   = "DMAR-MSI",
        .irq_unmask             = dmar_msi_unmask,
        .irq_mask               = dmar_msi_mask,
        .irq_ack                = irq_chip_ack_parent,
        .irq_set_affinity       = msi_domain_set_affinity,
        .irq_retrigger          = irq_chip_retrigger_hierarchy,
        .irq_compose_msi_msg    = dmar_msi_compose_msg,
        .irq_write_msi_msg      = dmar_msi_write_msg,
        .flags                  = IRQCHIP_SKIP_SET_WAKE | IRQCHIP_MOVE_DEFERRED |
                                  IRQCHIP_AFFINITY_PRE_STARTUP,
};

static int dmar_msi_init(struct irq_domain *domain,
                         struct msi_domain_info *info, unsigned int virq,
                         irq_hw_number_t hwirq, msi_alloc_info_t *arg)
{
        irq_domain_set_info(domain, virq, arg->devid, info->chip, NULL,
                            handle_edge_irq, arg->data, "edge");

        return 0;
}

static struct msi_domain_ops dmar_msi_domain_ops = {
        .msi_init       = dmar_msi_init,
};

static struct msi_domain_info dmar_msi_domain_info = {
        .ops            = &dmar_msi_domain_ops,
        .chip           = &dmar_msi_controller,
        .flags          = MSI_FLAG_USE_DEF_DOM_OPS,
};

static struct irq_domain *dmar_get_irq_domain(void)
{
        static struct irq_domain *dmar_domain;
        static DEFINE_MUTEX(dmar_lock);
        struct fwnode_handle *fn;

        mutex_lock(&dmar_lock);
        if (dmar_domain)
                goto out;

        fn = irq_domain_alloc_named_fwnode("DMAR-MSI");
        if (fn) {
                dmar_domain = msi_create_irq_domain(fn, &dmar_msi_domain_info,
                                                    x86_vector_domain);
                if (!dmar_domain)
                        irq_domain_free_fwnode(fn);
        }
out:
        mutex_unlock(&dmar_lock);
        return dmar_domain;
}

int dmar_alloc_hwirq(int id, int node, void *arg)
{
        struct irq_domain *domain = dmar_get_irq_domain();
        struct irq_alloc_info info;

        if (!domain)
                return -1;

        init_irq_alloc_info(&info, NULL);
        info.type = X86_IRQ_ALLOC_TYPE_DMAR;
        info.devid = id;
        info.hwirq = id;
        info.data = arg;

        return irq_domain_alloc_irqs(domain, 1, node, &info);
}

void dmar_free_hwirq(int irq)
{
        irq_domain_free_irqs(irq, 1);
}
#endif

bool arch_restore_msi_irqs(struct pci_dev *dev)
{
        return xen_initdom_restore_msi(dev);
}