// SPDX-License-Identifier: GPL-2.0-only
/*
 * Xen PCI - handle PCI (INTx) and MSI infrastructure calls for PV, HVM and
 * initial domain support. We also handle the DSDT _PRT callbacks for GSI's
 * used in HVM and initial domain mode (PV does not parse ACPI, so it has no
 * concept of GSIs). Under PV we hook under the pnbbios API for IRQs and
 * 0xcf8 PCI configuration read/write.
 *
 *   Author: Ryan Wilson <hap9@epoch.ncsc.mil>
 *           Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
 *           Stefano Stabellini <stefano.stabellini@eu.citrix.com>
 */
#include <linux/export.h>
#include <linux/init.h>
#include <linux/pci.h>
#include <linux/acpi.h>

#include <linux/io.h>
#include <asm/io_apic.h>
#include <asm/pci_x86.h>

#include <asm/xen/hypervisor.h>

#include <xen/features.h>
#include <xen/events.h>
#include <xen/pci.h>
#include <asm/xen/pci.h>
#include <asm/xen/cpuid.h>
#include <asm/apic.h>
#include <asm/acpi.h>
#include <asm/i8259.h>

static int xen_pcifront_enable_irq(struct pci_dev *dev)
{
        int rc;
        int share = 1;
        int pirq;
        u8 gsi;

        rc = pci_read_config_byte(dev, PCI_INTERRUPT_LINE, &gsi);
        if (rc) {
                dev_warn(&dev->dev, "Xen PCI: failed to read interrupt line: %d\n",
                         rc);
                return pcibios_err_to_errno(rc);
        }
        /* In PV DomU the Xen PCI backend puts the PIRQ in the interrupt line.*/
        pirq = gsi;

        if (gsi < nr_legacy_irqs())
                share = 0;

        rc = xen_bind_pirq_gsi_to_irq(gsi, pirq, share, "pcifront");
        if (rc < 0) {
                dev_warn(&dev->dev, "Xen PCI: failed to bind GSI%d (PIRQ%d) to IRQ: %d\n",
                         gsi, pirq, rc);
                return rc;
        }

        dev->irq = rc;
        dev_info(&dev->dev, "Xen PCI mapped GSI%d to IRQ%d\n", gsi, dev->irq);
        return 0;
}

#ifdef CONFIG_ACPI
static int xen_register_pirq(u32 gsi, int triggering, bool set_pirq)
{
        int rc, pirq = -1, irq;
        struct physdev_map_pirq map_irq;
        int shareable = 0;
        char *name;

        irq = xen_irq_from_gsi(gsi);
        if (irq > 0)
                return irq;

        if (set_pirq)
                pirq = gsi;

        map_irq.domid = DOMID_SELF;
        map_irq.type = MAP_PIRQ_TYPE_GSI;
        map_irq.index = gsi;
        map_irq.pirq = pirq;

        rc = HYPERVISOR_physdev_op(PHYSDEVOP_map_pirq, &map_irq);
        if (rc) {
                printk(KERN_WARNING "xen map irq failed %d\n", rc);
                return -1;
        }

        if (triggering == ACPI_EDGE_SENSITIVE) {
                shareable = 0;
                name = "ioapic-edge";
        } else {
                shareable = 1;
                name = "ioapic-level";
        }

        irq = xen_bind_pirq_gsi_to_irq(gsi, map_irq.pirq, shareable, name);
        if (irq < 0)
                goto out;

        printk(KERN_DEBUG "xen: --> pirq=%d -> irq=%d (gsi=%d)\n", map_irq.pirq, irq, gsi);
out:
        return irq;
}

static int acpi_register_gsi_xen_hvm(struct device *dev, u32 gsi,
                                     int trigger, int polarity)
{
        if (!xen_hvm_domain())
                return -1;

        return xen_register_pirq(gsi, trigger,
                                 false /* no mapping of GSI to PIRQ */);
}

#ifdef CONFIG_XEN_PV_DOM0
static int xen_register_gsi(u32 gsi, int triggering, int polarity)
{
        int rc, irq;
        struct physdev_setup_gsi setup_gsi;

        if (!xen_pv_domain())
                return -1;

        printk(KERN_DEBUG "xen: registering gsi %u triggering %d polarity %d\n",
                        gsi, triggering, polarity);

        irq = xen_register_pirq(gsi, triggering, true);

        setup_gsi.gsi = gsi;
        setup_gsi.triggering = (triggering == ACPI_EDGE_SENSITIVE ? 0 : 1);
        setup_gsi.polarity = (polarity == ACPI_ACTIVE_HIGH ? 0 : 1);

        rc = HYPERVISOR_physdev_op(PHYSDEVOP_setup_gsi, &setup_gsi);
        if (rc == -EEXIST)
                printk(KERN_INFO "Already setup the GSI :%d\n", gsi);
        else if (rc) {
                printk(KERN_ERR "Failed to setup GSI :%d, err_code:%d\n",
                                gsi, rc);
        }

        return irq;
}

static int acpi_register_gsi_xen(struct device *dev, u32 gsi,
                                 int trigger, int polarity)
{
        return xen_register_gsi(gsi, trigger, polarity);
}
#endif
#endif

#if defined(CONFIG_PCI_MSI)
#include <linux/msi.h>

struct xen_pci_frontend_ops *xen_pci_frontend;
EXPORT_SYMBOL_GPL(xen_pci_frontend);

struct xen_msi_ops {
        int (*setup_msi_irqs)(struct pci_dev *dev, int nvec, int type);
        void (*teardown_msi_irqs)(struct pci_dev *dev);
};

static struct xen_msi_ops xen_msi_ops __ro_after_init;

static int xen_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
{
        int irq, ret, i;
        struct msi_desc *msidesc;
        int *v;

        if (type == PCI_CAP_ID_MSI && nvec > 1)
                return 1;

        v = kzalloc_objs(int, max(1, nvec));
        if (!v)
                return -ENOMEM;

        if (type == PCI_CAP_ID_MSIX)
                ret = xen_pci_frontend_enable_msix(dev, v, nvec);
        else
                ret = xen_pci_frontend_enable_msi(dev, v);
        if (ret)
                goto error;
        i = 0;
        msi_for_each_desc(msidesc, &dev->dev, MSI_DESC_NOTASSOCIATED) {
                irq = xen_bind_pirq_msi_to_irq(dev, msidesc, v[i],
                                               (type == PCI_CAP_ID_MSI) ? nvec : 1,
                                               (type == PCI_CAP_ID_MSIX) ?
                                               "pcifront-msi-x" :
                                               "pcifront-msi",
                                                DOMID_SELF);
                if (irq < 0) {
                        ret = irq;
                        goto free;
                }
                i++;
        }
        kfree(v);
        return msi_device_populate_sysfs(&dev->dev);

error:
        if (ret == -ENOSYS)
                dev_err(&dev->dev, "Xen PCI frontend has not registered MSI/MSI-X support!\n");
        else if (ret)
                dev_err(&dev->dev, "Xen PCI frontend error: %d!\n", ret);
free:
        kfree(v);
        return ret;
}

static void xen_msi_compose_msg(struct pci_dev *pdev, unsigned int pirq,
                struct msi_msg *msg)
{
        /*
         * We set vector == 0 to tell the hypervisor we don't care about
         * it, but we want a pirq setup instead.  We use the dest_id fields
         * to pass the pirq that we want.
         */
        memset(msg, 0, sizeof(*msg));
        msg->address_hi = X86_MSI_BASE_ADDRESS_HIGH;
        msg->arch_addr_hi.destid_8_31 = pirq >> 8;
        msg->arch_addr_lo.destid_0_7 = pirq & 0xFF;
        msg->arch_addr_lo.base_address = X86_MSI_BASE_ADDRESS_LOW;
        msg->arch_data.delivery_mode = APIC_DELIVERY_MODE_EXTINT;
}

static int xen_hvm_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
{
        int irq, pirq;
        struct msi_desc *msidesc;
        struct msi_msg msg;

        if (type == PCI_CAP_ID_MSI && nvec > 1)
                return 1;

        msi_for_each_desc(msidesc, &dev->dev, MSI_DESC_NOTASSOCIATED) {
                pirq = xen_allocate_pirq_msi(dev, msidesc);
                if (pirq < 0) {
                        irq = -ENODEV;
                        goto error;
                }
                xen_msi_compose_msg(dev, pirq, &msg);
                __pci_write_msi_msg(msidesc, &msg);
                dev_dbg(&dev->dev, "xen: msi bound to pirq=%d\n", pirq);
                irq = xen_bind_pirq_msi_to_irq(dev, msidesc, pirq,
                                               (type == PCI_CAP_ID_MSI) ? nvec : 1,
                                               (type == PCI_CAP_ID_MSIX) ?
                                               "msi-x" : "msi",
                                               DOMID_SELF);
                if (irq < 0)
                        goto error;
                dev_dbg(&dev->dev,
                        "xen: msi --> pirq=%d --> irq=%d\n", pirq, irq);
        }
        return msi_device_populate_sysfs(&dev->dev);

error:
        dev_err(&dev->dev, "Failed to create MSI%s! ret=%d!\n",
                type == PCI_CAP_ID_MSI ? "" : "-X", irq);
        return irq;
}

#ifdef CONFIG_XEN_PV_DOM0
static bool __read_mostly pci_seg_supported = true;

static int xen_initdom_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
{
        int ret = 0;
        struct msi_desc *msidesc;

        msi_for_each_desc(msidesc, &dev->dev, MSI_DESC_NOTASSOCIATED) {
                struct physdev_map_pirq map_irq;
                domid_t domid;

                domid = ret = xen_find_device_domain_owner(dev);
                /* N.B. Casting int's -ENODEV to uint16_t results in 0xFFED,
                 * hence check ret value for < 0. */
                if (ret < 0)
                        domid = DOMID_SELF;

                memset(&map_irq, 0, sizeof(map_irq));
                map_irq.domid = domid;
                map_irq.type = MAP_PIRQ_TYPE_MSI_SEG;
                map_irq.index = -1;
                map_irq.pirq = -1;
                map_irq.bus = dev->bus->number |
                              (pci_domain_nr(dev->bus) << 16);
                map_irq.devfn = dev->devfn;

                if (type == PCI_CAP_ID_MSI && nvec > 1) {
                        map_irq.type = MAP_PIRQ_TYPE_MULTI_MSI;
                        map_irq.entry_nr = nvec;
                } else if (type == PCI_CAP_ID_MSIX) {
                        int pos;
                        unsigned long flags;
                        u32 table_offset, bir;

                        pos = dev->msix_cap;
                        pci_read_config_dword(dev, pos + PCI_MSIX_TABLE,
                                              &table_offset);
                        bir = (u8)(table_offset & PCI_MSIX_TABLE_BIR);
                        flags = pci_resource_flags(dev, bir);
                        if (!flags || (flags & IORESOURCE_UNSET))
                                return -EINVAL;

                        map_irq.table_base = pci_resource_start(dev, bir);
                        map_irq.entry_nr = msidesc->msi_index;
                }

                ret = -EINVAL;
                if (pci_seg_supported)
                        ret = HYPERVISOR_physdev_op(PHYSDEVOP_map_pirq,
                                                    &map_irq);
                if (type == PCI_CAP_ID_MSI && nvec > 1 && ret) {
                        /*
                         * If MAP_PIRQ_TYPE_MULTI_MSI is not available
                         * there's nothing else we can do in this case.
                         * Just set ret > 0 so driver can retry with
                         * single MSI.
                         */
                        ret = 1;
                        goto out;
                }
                if (ret == -EINVAL && !pci_domain_nr(dev->bus)) {
                        map_irq.type = MAP_PIRQ_TYPE_MSI;
                        map_irq.index = -1;
                        map_irq.pirq = -1;
                        map_irq.bus = dev->bus->number;
                        ret = HYPERVISOR_physdev_op(PHYSDEVOP_map_pirq,
                                                    &map_irq);
                        if (ret != -EINVAL)
                                pci_seg_supported = false;
                }
                if (ret) {
                        dev_warn(&dev->dev, "xen map irq failed %d for %d domain\n",
                                 ret, domid);
                        goto out;
                }

                ret = xen_bind_pirq_msi_to_irq(dev, msidesc, map_irq.pirq,
                                               (type == PCI_CAP_ID_MSI) ? nvec : 1,
                                               (type == PCI_CAP_ID_MSIX) ? "msi-x" : "msi",
                                               domid);
                if (ret < 0)
                        goto out;
        }
        ret = msi_device_populate_sysfs(&dev->dev);
out:
        return ret;
}

bool xen_initdom_restore_msi(struct pci_dev *dev)
{
        int ret = 0;

        if (!xen_initial_domain())
                return true;

        if (pci_seg_supported) {
                struct physdev_pci_device restore_ext;

                restore_ext.seg = pci_domain_nr(dev->bus);
                restore_ext.bus = dev->bus->number;
                restore_ext.devfn = dev->devfn;
                ret = HYPERVISOR_physdev_op(PHYSDEVOP_restore_msi_ext,
                                        &restore_ext);
                if (ret == -ENOSYS)
                        pci_seg_supported = false;
                WARN(ret && ret != -ENOSYS, "restore_msi_ext -> %d\n", ret);
        }
        if (!pci_seg_supported) {
                struct physdev_restore_msi restore;

                restore.bus = dev->bus->number;
                restore.devfn = dev->devfn;
                ret = HYPERVISOR_physdev_op(PHYSDEVOP_restore_msi, &restore);
                WARN(ret && ret != -ENOSYS, "restore_msi -> %d\n", ret);
        }
        return false;
}
#else /* CONFIG_XEN_PV_DOM0 */
#define xen_initdom_setup_msi_irqs      NULL
#endif /* !CONFIG_XEN_PV_DOM0 */

static void xen_teardown_msi_irqs(struct pci_dev *dev)
{
        struct msi_desc *msidesc;
        int i;

        msi_for_each_desc(msidesc, &dev->dev, MSI_DESC_ASSOCIATED) {
                for (i = 0; i < msidesc->nvec_used; i++)
                        xen_destroy_irq(msidesc->irq + i);
                msidesc->irq = 0;
        }

        msi_device_destroy_sysfs(&dev->dev);
}

static void xen_pv_teardown_msi_irqs(struct pci_dev *dev)
{
        if (dev->msix_enabled)
                xen_pci_frontend_disable_msix(dev);
        else
                xen_pci_frontend_disable_msi(dev);

        xen_teardown_msi_irqs(dev);
}

static int xen_msi_domain_alloc_irqs(struct irq_domain *domain,
                                     struct device *dev,  int nvec)
{
        int type;

        if (WARN_ON_ONCE(!dev_is_pci(dev)))
                return -EINVAL;

        type = to_pci_dev(dev)->msix_enabled ? PCI_CAP_ID_MSIX : PCI_CAP_ID_MSI;

        return xen_msi_ops.setup_msi_irqs(to_pci_dev(dev), nvec, type);
}

static void xen_msi_domain_free_irqs(struct irq_domain *domain,
                                     struct device *dev)
{
        if (WARN_ON_ONCE(!dev_is_pci(dev)))
                return;

        xen_msi_ops.teardown_msi_irqs(to_pci_dev(dev));
}

static struct msi_domain_ops xen_pci_msi_domain_ops = {
        .domain_alloc_irqs      = xen_msi_domain_alloc_irqs,
        .domain_free_irqs       = xen_msi_domain_free_irqs,
};

static struct msi_domain_info xen_pci_msi_domain_info = {
        .flags                  = MSI_FLAG_PCI_MSIX | MSI_FLAG_FREE_MSI_DESCS |
                                  MSI_FLAG_DEV_SYSFS | MSI_FLAG_NO_MASK,
        .ops                    = &xen_pci_msi_domain_ops,
};

/*
 * This irq domain is a blatant violation of the irq domain design, but
 * distangling XEN into real irq domains is not a job for mere mortals with
 * limited XENology. But it's the least dangerous way for a mere mortal to
 * get rid of the arch_*_msi_irqs() hackery in order to store the irq
 * domain pointer in struct device. This irq domain wrappery allows to do
 * that without breaking XEN terminally.
 */
static __init struct irq_domain *xen_create_pci_msi_domain(void)
{
        struct irq_domain *d = NULL;
        struct fwnode_handle *fn;

        fn = irq_domain_alloc_named_fwnode("XEN-MSI");
        if (fn)
                d = msi_create_irq_domain(fn, &xen_pci_msi_domain_info, NULL);

        /* FIXME: No idea how to survive if this fails */
        BUG_ON(!d);

        return d;
}

static __init void xen_setup_pci_msi(void)
{
        if (xen_pv_domain()) {
                if (xen_initial_domain())
                        xen_msi_ops.setup_msi_irqs = xen_initdom_setup_msi_irqs;
                else
                        xen_msi_ops.setup_msi_irqs = xen_setup_msi_irqs;
                xen_msi_ops.teardown_msi_irqs = xen_pv_teardown_msi_irqs;
        } else if (xen_hvm_domain()) {
                xen_msi_ops.setup_msi_irqs = xen_hvm_setup_msi_irqs;
                xen_msi_ops.teardown_msi_irqs = xen_teardown_msi_irqs;
        } else {
                WARN_ON_ONCE(1);
                return;
        }

        /*
         * Override the PCI/MSI irq domain init function. No point
         * in allocating the native domain and never use it.
         */
        x86_init.irqs.create_pci_msi_domain = xen_create_pci_msi_domain;
}

#else /* CONFIG_PCI_MSI */
static inline void xen_setup_pci_msi(void) { }
#endif /* CONFIG_PCI_MSI */

int __init pci_xen_init(void)
{
        if (!xen_pv_domain() || xen_initial_domain())
                return -ENODEV;

        printk(KERN_INFO "PCI: setting up Xen PCI frontend stub\n");

        pcibios_set_cache_line_size();

        pcibios_enable_irq = xen_pcifront_enable_irq;
        pcibios_disable_irq = NULL;

        /* Keep ACPI out of the picture */
        acpi_noirq_set();

        xen_setup_pci_msi();
        return 0;
}

#ifdef CONFIG_PCI_MSI
static void __init xen_hvm_msi_init(void)
{
        if (!apic_is_disabled) {
                /*
                 * If hardware supports (x2)APIC virtualization (as indicated
                 * by hypervisor's leaf 4) then we don't need to use pirqs/
                 * event channels for MSI handling and instead use regular
                 * APIC processing
                 */
                uint32_t eax = cpuid_eax(xen_cpuid_base() + 4);

                if (((eax & XEN_HVM_CPUID_X2APIC_VIRT) && x2apic_mode) ||
                    ((eax & XEN_HVM_CPUID_APIC_ACCESS_VIRT) && boot_cpu_has(X86_FEATURE_APIC)))
                        return;
        }
        xen_setup_pci_msi();
}
#endif

int __init pci_xen_hvm_init(void)
{
        if (!xen_have_vector_callback || !xen_feature(XENFEAT_hvm_pirqs))
                return 0;

#ifdef CONFIG_ACPI
        /*
         * We don't want to change the actual ACPI delivery model,
         * just how GSIs get registered.
         */
        __acpi_register_gsi = acpi_register_gsi_xen_hvm;
        __acpi_unregister_gsi = NULL;
#endif

#ifdef CONFIG_PCI_MSI
        /*
         * We need to wait until after x2apic is initialized
         * before we can set MSI IRQ ops.
         */
        x86_platform.apic_post_init = xen_hvm_msi_init;
#endif
        return 0;
}

#ifdef CONFIG_XEN_PV_DOM0
int __init pci_xen_initial_domain(void)
{
        int irq;

        xen_setup_pci_msi();
        __acpi_register_gsi = acpi_register_gsi_xen;
        __acpi_unregister_gsi = NULL;
        /*
         * Pre-allocate the legacy IRQs.  Use NR_LEGACY_IRQS here
         * because we don't have a PIC and thus nr_legacy_irqs() is zero.
         */
        for (irq = 0; irq < NR_IRQS_LEGACY; irq++) {
                int trigger, polarity;

                if (acpi_get_override_irq(irq, &trigger, &polarity) == -1)
                        continue;

                xen_register_pirq(irq,
                        trigger ? ACPI_LEVEL_SENSITIVE : ACPI_EDGE_SENSITIVE,
                        true /* Map GSI to PIRQ */);
        }
        if (0 == nr_ioapics) {
                for (irq = 0; irq < nr_legacy_irqs(); irq++)
                        xen_bind_pirq_gsi_to_irq(irq, irq, 0, "xt-pic");
        }
        return 0;
}
#endif