/*
 * Shared interrupt handling code for IPR and INTC2 types of IRQs.
 *
 * Copyright (C) 2007, 2008 Magnus Damm
 * Copyright (C) 2009 - 2012 Paul Mundt
 *
 * Based on intc2.c and ipr.c
 *
 * Copyright (C) 1999  Niibe Yutaka & Takeshi Yaegashi
 * Copyright (C) 2000  Kazumoto Kojima
 * Copyright (C) 2001  David J. Mckay (david.mckay@st.com)
 * Copyright (C) 2003  Takashi Kusuda <kusuda-takashi@hitachi-ul.co.jp>
 * Copyright (C) 2005, 2006  Paul Mundt
 *
 * 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.
 */
#define pr_fmt(fmt) "intc: " fmt

#include <linux/init.h>
#include <linux/irq.h>
#include <linux/io.h>
#include <linux/slab.h>
#include <linux/stat.h>
#include <linux/interrupt.h>
#include <linux/sh_intc.h>
#include <linux/irqdomain.h>
#include <linux/device.h>
#include <linux/syscore_ops.h>
#include <linux/list.h>
#include <linux/spinlock.h>
#include <linux/radix-tree.h>
#include <linux/export.h>
#include <linux/sort.h>
#include "internals.h"

LIST_HEAD(intc_list);
DEFINE_RAW_SPINLOCK(intc_big_lock);
static unsigned int nr_intc_controllers;

/*
 * Default priority level
 * - this needs to be at least 2 for 5-bit priorities on 7780
 */
static unsigned int default_prio_level = 2;     /* 2 - 16 */
static unsigned int intc_prio_level[INTC_NR_IRQS];      /* for now */

unsigned int intc_get_dfl_prio_level(void)
{
        return default_prio_level;
}

unsigned int intc_get_prio_level(unsigned int irq)
{
        return intc_prio_level[irq];
}

void intc_set_prio_level(unsigned int irq, unsigned int level)
{
        unsigned long flags;

        raw_spin_lock_irqsave(&intc_big_lock, flags);
        intc_prio_level[irq] = level;
        raw_spin_unlock_irqrestore(&intc_big_lock, flags);
}

static void intc_redirect_irq(struct irq_desc *desc)
{
        generic_handle_irq((unsigned int)irq_desc_get_handler_data(desc));
}

static void __init intc_register_irq(struct intc_desc *desc,
                                     struct intc_desc_int *d,
                                     intc_enum enum_id,
                                     unsigned int irq)
{
        struct intc_handle_int *hp;
        struct irq_data *irq_data;
        unsigned int data[2], primary;
        unsigned long flags;

        raw_spin_lock_irqsave(&intc_big_lock, flags);
        radix_tree_insert(&d->tree, enum_id, intc_irq_xlate_get(irq));
        raw_spin_unlock_irqrestore(&intc_big_lock, flags);

        /*
         * Prefer single interrupt source bitmap over other combinations:
         *
         * 1. bitmap, single interrupt source
         * 2. priority, single interrupt source
         * 3. bitmap, multiple interrupt sources (groups)
         * 4. priority, multiple interrupt sources (groups)
         */
        data[0] = intc_get_mask_handle(desc, d, enum_id, 0);
        data[1] = intc_get_prio_handle(desc, d, enum_id, 0);

        primary = 0;
        if (!data[0] && data[1])
                primary = 1;

        if (!data[0] && !data[1])
                pr_warn("missing unique irq mask for irq %d (vect 0x%04x)\n",
                        irq, irq2evt(irq));

        data[0] = data[0] ? data[0] : intc_get_mask_handle(desc, d, enum_id, 1);
        data[1] = data[1] ? data[1] : intc_get_prio_handle(desc, d, enum_id, 1);

        if (!data[primary])
                primary ^= 1;

        BUG_ON(!data[primary]); /* must have primary masking method */

        irq_data = irq_get_irq_data(irq);

        disable_irq_nosync(irq);
        irq_set_chip_and_handler_name(irq, &d->chip, handle_level_irq,
                                      "level");
        irq_set_chip_data(irq, (void *)data[primary]);

        /*
         * set priority level
         */
        intc_set_prio_level(irq, intc_get_dfl_prio_level());

        /* enable secondary masking method if present */
        if (data[!primary])
                _intc_enable(irq_data, data[!primary]);

        /* add irq to d->prio list if priority is available */
        if (data[1]) {
                hp = d->prio + d->nr_prio;
                hp->irq = irq;
                hp->handle = data[1];

                if (primary) {
                        /*
                         * only secondary priority should access registers, so
                         * set _INTC_FN(h) = REG_FN_ERR for intc_set_priority()
                         */
                        hp->handle &= ~_INTC_MK(0x0f, 0, 0, 0, 0, 0);
                        hp->handle |= _INTC_MK(REG_FN_ERR, 0, 0, 0, 0, 0);
                }
                d->nr_prio++;
        }

        /* add irq to d->sense list if sense is available */
        data[0] = intc_get_sense_handle(desc, d, enum_id);
        if (data[0]) {
                (d->sense + d->nr_sense)->irq = irq;
                (d->sense + d->nr_sense)->handle = data[0];
                d->nr_sense++;
        }

        /* irq should be disabled by default */
        d->chip.irq_mask(irq_data);

        intc_set_ack_handle(irq, desc, d, enum_id);
        intc_set_dist_handle(irq, desc, d, enum_id);

        activate_irq(irq);
}

static unsigned int __init save_reg(struct intc_desc_int *d,
                                    unsigned int cnt,
                                    unsigned long value,
                                    unsigned int smp)
{
        if (value) {
                value = intc_phys_to_virt(d, value);

                d->reg[cnt] = value;
#ifdef CONFIG_SMP
                d->smp[cnt] = smp;
#endif
                return 1;
        }

        return 0;
}

static bool __init intc_map(struct irq_domain *domain, int irq)
{
        if (!irq_to_desc(irq) && irq_alloc_desc_at(irq, NUMA_NO_NODE) != irq) {
                pr_err("uname to allocate IRQ %d\n", irq);
                return false;
        }

        if (irq_domain_associate(domain, irq, irq)) {
                pr_err("domain association failure\n");
                return false;
        }

        return true;
}

int __init register_intc_controller(struct intc_desc *desc)
{
        unsigned int i, k, smp;
        struct intc_hw_desc *hw = &desc->hw;
        struct intc_desc_int *d;
        struct resource *res;

        pr_info("Registered controller '%s' with %u IRQs\n",
                desc->name, hw->nr_vectors);

        d = kzalloc(sizeof(*d), GFP_NOWAIT);
        if (!d)
                goto err0;

        INIT_LIST_HEAD(&d->list);
        list_add_tail(&d->list, &intc_list);

        raw_spin_lock_init(&d->lock);
        INIT_RADIX_TREE(&d->tree, GFP_ATOMIC);

        d->index = nr_intc_controllers;

        if (desc->num_resources) {
                d->nr_windows = desc->num_resources;
                d->window = kcalloc(d->nr_windows, sizeof(*d->window),
                                    GFP_NOWAIT);
                if (!d->window)
                        goto err1;

                for (k = 0; k < d->nr_windows; k++) {
                        res = desc->resource + k;
                        WARN_ON(resource_type(res) != IORESOURCE_MEM);
                        d->window[k].phys = res->start;
                        d->window[k].size = resource_size(res);
                        d->window[k].virt = ioremap(res->start,
                                                    resource_size(res));
                        if (!d->window[k].virt)
                                goto err2;
                }
        }

        d->nr_reg = hw->mask_regs ? hw->nr_mask_regs * 2 : 0;
#ifdef CONFIG_INTC_BALANCING
        if (d->nr_reg)
                d->nr_reg += hw->nr_mask_regs;
#endif
        d->nr_reg += hw->prio_regs ? hw->nr_prio_regs * 2 : 0;
        d->nr_reg += hw->sense_regs ? hw->nr_sense_regs : 0;
        d->nr_reg += hw->ack_regs ? hw->nr_ack_regs : 0;
        d->nr_reg += hw->subgroups ? hw->nr_subgroups : 0;

        d->reg = kcalloc(d->nr_reg, sizeof(*d->reg), GFP_NOWAIT);
        if (!d->reg)
                goto err2;

#ifdef CONFIG_SMP
        d->smp = kcalloc(d->nr_reg, sizeof(*d->smp), GFP_NOWAIT);
        if (!d->smp)
                goto err3;
#endif
        k = 0;

        if (hw->mask_regs) {
                for (i = 0; i < hw->nr_mask_regs; i++) {
                        smp = IS_SMP(hw->mask_regs[i]);
                        k += save_reg(d, k, hw->mask_regs[i].set_reg, smp);
                        k += save_reg(d, k, hw->mask_regs[i].clr_reg, smp);
#ifdef CONFIG_INTC_BALANCING
                        k += save_reg(d, k, hw->mask_regs[i].dist_reg, 0);
#endif
                }
        }

        if (hw->prio_regs) {
                d->prio = kcalloc(hw->nr_vectors, sizeof(*d->prio),
                                  GFP_NOWAIT);
                if (!d->prio)
                        goto err4;

                for (i = 0; i < hw->nr_prio_regs; i++) {
                        smp = IS_SMP(hw->prio_regs[i]);
                        k += save_reg(d, k, hw->prio_regs[i].set_reg, smp);
                        k += save_reg(d, k, hw->prio_regs[i].clr_reg, smp);
                }

                sort(d->prio, hw->nr_prio_regs, sizeof(*d->prio),
                     intc_handle_int_cmp, NULL);
        }

        if (hw->sense_regs) {
                d->sense = kcalloc(hw->nr_vectors, sizeof(*d->sense),
                                   GFP_NOWAIT);
                if (!d->sense)
                        goto err5;

                for (i = 0; i < hw->nr_sense_regs; i++)
                        k += save_reg(d, k, hw->sense_regs[i].reg, 0);

                sort(d->sense, hw->nr_sense_regs, sizeof(*d->sense),
                     intc_handle_int_cmp, NULL);
        }

        if (hw->subgroups)
                for (i = 0; i < hw->nr_subgroups; i++)
                        if (hw->subgroups[i].reg)
                                k+= save_reg(d, k, hw->subgroups[i].reg, 0);

        memcpy(&d->chip, &intc_irq_chip, sizeof(struct irq_chip));
        d->chip.name = desc->name;

        if (hw->ack_regs)
                for (i = 0; i < hw->nr_ack_regs; i++)
                        k += save_reg(d, k, hw->ack_regs[i].set_reg, 0);
        else
                d->chip.irq_mask_ack = d->chip.irq_disable;

        /* disable bits matching force_disable before registering irqs */
        if (desc->force_disable)
                intc_enable_disable_enum(desc, d, desc->force_disable, 0);

        /* disable bits matching force_enable before registering irqs */
        if (desc->force_enable)
                intc_enable_disable_enum(desc, d, desc->force_enable, 0);

        BUG_ON(k > 256); /* _INTC_ADDR_E() and _INTC_ADDR_D() are 8 bits */

        intc_irq_domain_init(d, hw);

        /* register the vectors one by one */
        for (i = 0; i < hw->nr_vectors; i++) {
                struct intc_vect *vect = hw->vectors + i;
                unsigned int irq = evt2irq(vect->vect);

                if (!vect->enum_id)
                        continue;

                if (!intc_map(d->domain, irq))
                        continue;

                intc_irq_xlate_set(irq, vect->enum_id, d);
                intc_register_irq(desc, d, vect->enum_id, irq);

                for (k = i + 1; k < hw->nr_vectors; k++) {
                        struct intc_vect *vect2 = hw->vectors + k;
                        unsigned int irq2 = evt2irq(vect2->vect);

                        if (vect->enum_id != vect2->enum_id)
                                continue;

                        /*
                         * In the case of multi-evt handling and sparse
                         * IRQ support, each vector still needs to have
                         * its own backing irq_desc.
                         */
                        if (!intc_map(d->domain, irq2))
                                continue;

                        vect2->enum_id = 0;

                        /* redirect this interrupts to the first one */
                        irq_set_chip(irq2, &dummy_irq_chip);
                        irq_set_chained_handler_and_data(irq2,
                                                         intc_redirect_irq,
                                                         (void *)irq);
                }
        }

        intc_subgroup_init(desc, d);

        /* enable bits matching force_enable after registering irqs */
        if (desc->force_enable)
                intc_enable_disable_enum(desc, d, desc->force_enable, 1);

        d->skip_suspend = desc->skip_syscore_suspend;

        nr_intc_controllers++;

        return 0;
err5:
        kfree(d->prio);
err4:
#ifdef CONFIG_SMP
        kfree(d->smp);
err3:
#endif
        kfree(d->reg);
err2:
        for (k = 0; k < d->nr_windows; k++)
                if (d->window[k].virt)
                        iounmap(d->window[k].virt);

        kfree(d->window);
err1:
        kfree(d);
err0:
        pr_err("unable to allocate INTC memory\n");

        return -ENOMEM;
}

static int intc_suspend(void)
{
        struct intc_desc_int *d;

        list_for_each_entry(d, &intc_list, list) {
                int irq;

                if (d->skip_suspend)
                        continue;

                /* enable wakeup irqs belonging to this intc controller */
                for_each_active_irq(irq) {
                        struct irq_data *data;
                        struct irq_chip *chip;

                        data = irq_get_irq_data(irq);
                        chip = irq_data_get_irq_chip(data);
                        if (chip != &d->chip)
                                continue;
                        if (irqd_is_wakeup_set(data))
                                chip->irq_enable(data);
                }
        }
        return 0;
}

static void intc_resume(void)
{
        struct intc_desc_int *d;

        list_for_each_entry(d, &intc_list, list) {
                int irq;

                if (d->skip_suspend)
                        continue;

                for_each_active_irq(irq) {
                        struct irq_data *data;
                        struct irq_chip *chip;

                        data = irq_get_irq_data(irq);
                        chip = irq_data_get_irq_chip(data);
                        /*
                         * This will catch the redirect and VIRQ cases
                         * due to the dummy_irq_chip being inserted.
                         */
                        if (chip != &d->chip)
                                continue;
                        if (irqd_irq_disabled(data))
                                chip->irq_disable(data);
                        else
                                chip->irq_enable(data);
                }
        }
}

struct syscore_ops intc_syscore_ops = {
        .suspend        = intc_suspend,
        .resume         = intc_resume,
};

struct bus_type intc_subsys = {
        .name           = "intc",
        .dev_name       = "intc",
};

static ssize_t
show_intc_name(struct device *dev, struct device_attribute *attr, char *buf)
{
        struct intc_desc_int *d;

        d = container_of(dev, struct intc_desc_int, dev);

        return sprintf(buf, "%s\n", d->chip.name);
}

static DEVICE_ATTR(name, S_IRUGO, show_intc_name, NULL);

static int __init register_intc_devs(void)
{
        struct intc_desc_int *d;
        int error;

        register_syscore_ops(&intc_syscore_ops);

        error = subsys_system_register(&intc_subsys, NULL);
        if (!error) {
                list_for_each_entry(d, &intc_list, list) {
                        d->dev.id = d->index;
                        d->dev.bus = &intc_subsys;
                        error = device_register(&d->dev);
                        if (error == 0)
                                error = device_create_file(&d->dev,
                                                           &dev_attr_name);
                        if (error)
                                break;
                }
        }

        if (error)
                pr_err("device registration error\n");

        return error;
}
device_initcall(register_intc_devs);