/*
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * SGI UV IRQ functions
 *
 * Copyright (C) 2008 Silicon Graphics, Inc. All rights reserved.
 */

#include <linux/export.h>
#include <linux/rbtree.h>
#include <linux/slab.h>
#include <linux/irq.h>

#include <asm/irqdomain.h>
#include <asm/apic.h>
#include <asm/uv/uv_irq.h>
#include <asm/uv/uv_hub.h>

/* MMR offset and pnode of hub sourcing interrupts for a given irq */
struct uv_irq_2_mmr_pnode {
        unsigned long           offset;
        int                     pnode;
};

static void uv_program_mmr(struct irq_cfg *cfg, struct uv_irq_2_mmr_pnode *info)
{
        unsigned long mmr_value;
        struct uv_IO_APIC_route_entry *entry;

        BUILD_BUG_ON(sizeof(struct uv_IO_APIC_route_entry) !=
                     sizeof(unsigned long));

        mmr_value = 0;
        entry = (struct uv_IO_APIC_route_entry *)&mmr_value;
        entry->vector           = cfg->vector;
        entry->delivery_mode    = apic->irq_delivery_mode;
        entry->dest_mode        = apic->irq_dest_mode;
        entry->polarity         = 0;
        entry->trigger          = 0;
        entry->mask             = 0;
        entry->dest             = cfg->dest_apicid;

        uv_write_global_mmr64(info->pnode, info->offset, mmr_value);
}

static void uv_noop(struct irq_data *data) { }

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

static int
uv_set_irq_affinity(struct irq_data *data, const struct cpumask *mask,
                    bool force)
{
        struct irq_data *parent = data->parent_data;
        struct irq_cfg *cfg = irqd_cfg(data);
        int ret;

        ret = parent->chip->irq_set_affinity(parent, mask, force);
        if (ret >= 0) {
                uv_program_mmr(cfg, data->chip_data);
                send_cleanup_vector(cfg);
        }

        return ret;
}

static struct irq_chip uv_irq_chip = {
        .name                   = "UV-CORE",
        .irq_mask               = uv_noop,
        .irq_unmask             = uv_noop,
        .irq_eoi                = uv_ack_apic,
        .irq_set_affinity       = uv_set_irq_affinity,
};

static int uv_domain_alloc(struct irq_domain *domain, unsigned int virq,
                           unsigned int nr_irqs, void *arg)
{
        struct uv_irq_2_mmr_pnode *chip_data;
        struct irq_alloc_info *info = arg;
        struct irq_data *irq_data = irq_domain_get_irq_data(domain, virq);
        int ret;

        if (nr_irqs > 1 || !info || info->type != X86_IRQ_ALLOC_TYPE_UV)
                return -EINVAL;

        chip_data = kmalloc_node(sizeof(*chip_data), GFP_KERNEL,
                                 irq_data_get_node(irq_data));
        if (!chip_data)
                return -ENOMEM;

        ret = irq_domain_alloc_irqs_parent(domain, virq, nr_irqs, arg);
        if (ret >= 0) {
                if (info->uv_limit == UV_AFFINITY_CPU)
                        irq_set_status_flags(virq, IRQ_NO_BALANCING);
                else
                        irq_set_status_flags(virq, IRQ_MOVE_PCNTXT);

                chip_data->pnode = uv_blade_to_pnode(info->uv_blade);
                chip_data->offset = info->uv_offset;
                irq_domain_set_info(domain, virq, virq, &uv_irq_chip, chip_data,
                                    handle_percpu_irq, NULL, info->uv_name);
        } else {
                kfree(chip_data);
        }

        return ret;
}

static void uv_domain_free(struct irq_domain *domain, unsigned int virq,
                           unsigned int nr_irqs)
{
        struct irq_data *irq_data = irq_domain_get_irq_data(domain, virq);

        BUG_ON(nr_irqs != 1);
        kfree(irq_data->chip_data);
        irq_clear_status_flags(virq, IRQ_MOVE_PCNTXT);
        irq_clear_status_flags(virq, IRQ_NO_BALANCING);
        irq_domain_free_irqs_top(domain, virq, nr_irqs);
}

/*
 * Re-target the irq to the specified CPU and enable the specified MMR located
 * on the specified blade to allow the sending of MSIs to the specified CPU.
 */
static int uv_domain_activate(struct irq_domain *domain,
                              struct irq_data *irq_data, bool reserve)
{
        uv_program_mmr(irqd_cfg(irq_data), irq_data->chip_data);
        return 0;
}

/*
 * Disable the specified MMR located on the specified blade so that MSIs are
 * longer allowed to be sent.
 */
static void uv_domain_deactivate(struct irq_domain *domain,
                                 struct irq_data *irq_data)
{
        unsigned long mmr_value;
        struct uv_IO_APIC_route_entry *entry;

        mmr_value = 0;
        entry = (struct uv_IO_APIC_route_entry *)&mmr_value;
        entry->mask = 1;
        uv_program_mmr(irqd_cfg(irq_data), irq_data->chip_data);
}

static const struct irq_domain_ops uv_domain_ops = {
        .alloc          = uv_domain_alloc,
        .free           = uv_domain_free,
        .activate       = uv_domain_activate,
        .deactivate     = uv_domain_deactivate,
};

static struct irq_domain *uv_get_irq_domain(void)
{
        static struct irq_domain *uv_domain;
        static DEFINE_MUTEX(uv_lock);
        struct fwnode_handle *fn;

        mutex_lock(&uv_lock);
        if (uv_domain)
                goto out;

        fn = irq_domain_alloc_named_fwnode("UV-CORE");
        if (!fn)
                goto out;

        uv_domain = irq_domain_create_tree(fn, &uv_domain_ops, NULL);
        irq_domain_free_fwnode(fn);
        if (uv_domain)
                uv_domain->parent = x86_vector_domain;
out:
        mutex_unlock(&uv_lock);

        return uv_domain;
}

/*
 * Set up a mapping of an available irq and vector, and enable the specified
 * MMR that defines the MSI that is to be sent to the specified CPU when an
 * interrupt is raised.
 */
int uv_setup_irq(char *irq_name, int cpu, int mmr_blade,
                 unsigned long mmr_offset, int limit)
{
        struct irq_alloc_info info;
        struct irq_domain *domain = uv_get_irq_domain();

        if (!domain)
                return -ENOMEM;

        init_irq_alloc_info(&info, cpumask_of(cpu));
        info.type = X86_IRQ_ALLOC_TYPE_UV;
        info.uv_limit = limit;
        info.uv_blade = mmr_blade;
        info.uv_offset = mmr_offset;
        info.uv_name = irq_name;

        return irq_domain_alloc_irqs(domain, 1,
                                     uv_blade_to_memory_nid(mmr_blade), &info);
}
EXPORT_SYMBOL_GPL(uv_setup_irq);

/*
 * Tear down a mapping of an irq and vector, and disable the specified MMR that
 * defined the MSI that was to be sent to the specified CPU when an interrupt
 * was raised.
 *
 * Set mmr_blade and mmr_offset to what was passed in on uv_setup_irq().
 */
void uv_teardown_irq(unsigned int irq)
{
        irq_domain_free_irqs(irq, 1);
}
EXPORT_SYMBOL_GPL(uv_teardown_irq);