// SPDX-License-Identifier: GPL-2.0-only
/*
 * Broadcom BCM7120 style Level 2 interrupt controller driver
 *
 * Copyright (C) 2014 Broadcom Corporation
 */

#define pr_fmt(fmt)     KBUILD_MODNAME  ": " fmt

#include <linux/init.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/platform_device.h>
#include <linux/of.h>
#include <linux/of_irq.h>
#include <linux/of_address.h>
#include <linux/of_platform.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/io.h>
#include <linux/irqdomain.h>
#include <linux/reboot.h>
#include <linux/bitops.h>
#include <linux/irqchip.h>
#include <linux/irqchip/chained_irq.h>

/* Register offset in the L2 interrupt controller */
#define IRQEN           0x00
#define IRQSTAT         0x04

#define MAX_WORDS       4
#define MAX_MAPPINGS    (MAX_WORDS * 2)
#define IRQS_PER_WORD   32

struct bcm7120_l1_intc_data {
        struct bcm7120_l2_intc_data *b;
        u32 irq_map_mask[MAX_WORDS];
};

struct bcm7120_l2_intc_data {
        unsigned int n_words;
        void __iomem *map_base[MAX_MAPPINGS];
        void __iomem *pair_base[MAX_WORDS];
        int en_offset[MAX_WORDS];
        int stat_offset[MAX_WORDS];
        struct irq_domain *domain;
        bool can_wake;
        u32 irq_fwd_mask[MAX_WORDS];
        struct bcm7120_l1_intc_data *l1_data;
        int num_parent_irqs;
        const __be32 *map_mask_prop;
};

static void bcm7120_l2_intc_irq_handle(struct irq_desc *desc)
{
        struct bcm7120_l1_intc_data *data = irq_desc_get_handler_data(desc);
        struct bcm7120_l2_intc_data *b = data->b;
        struct irq_chip *chip = irq_desc_get_chip(desc);
        unsigned int idx;

        chained_irq_enter(chip, desc);

        for (idx = 0; idx < b->n_words; idx++) {
                int base = idx * IRQS_PER_WORD;
                struct irq_chip_generic *gc =
                        irq_get_domain_generic_chip(b->domain, base);
                unsigned long pending;
                int hwirq;

                irq_gc_lock(gc);
                pending = irq_reg_readl(gc, b->stat_offset[idx]) &
                                            gc->mask_cache &
                                            data->irq_map_mask[idx];
                irq_gc_unlock(gc);

                for_each_set_bit(hwirq, &pending, IRQS_PER_WORD) {
                        generic_handle_irq(irq_find_mapping(b->domain,
                                           base + hwirq));
                }
        }

        chained_irq_exit(chip, desc);
}

static void bcm7120_l2_intc_suspend(struct irq_chip_generic *gc)
{
        struct bcm7120_l2_intc_data *b = gc->private;
        struct irq_chip_type *ct = gc->chip_types;

        irq_gc_lock(gc);
        if (b->can_wake)
                irq_reg_writel(gc, gc->mask_cache | gc->wake_active,
                               ct->regs.mask);
        irq_gc_unlock(gc);
}

static void bcm7120_l2_intc_resume(struct irq_chip_generic *gc)
{
        struct irq_chip_type *ct = gc->chip_types;

        /* Restore the saved mask */
        irq_gc_lock(gc);
        irq_reg_writel(gc, gc->mask_cache, ct->regs.mask);
        irq_gc_unlock(gc);
}

static int bcm7120_l2_intc_init_one(struct device_node *dn,
                                        struct bcm7120_l2_intc_data *data,
                                        int irq, u32 *valid_mask)
{
        struct bcm7120_l1_intc_data *l1_data = &data->l1_data[irq];
        int parent_irq;
        unsigned int idx;

        parent_irq = irq_of_parse_and_map(dn, irq);
        if (!parent_irq) {
                pr_err("failed to map interrupt %d\n", irq);
                return -EINVAL;
        }

        /* For multiple parent IRQs with multiple words, this looks like:
         * <irq0_w0 irq0_w1 irq1_w0 irq1_w1 ...>
         *
         * We need to associate a given parent interrupt with its corresponding
         * map_mask in order to mask the status register with it because we
         * have the same handler being called for multiple parent interrupts.
         *
         * This is typically something needed on BCM7xxx (STB chips).
         */
        for (idx = 0; idx < data->n_words; idx++) {
                if (data->map_mask_prop) {
                        l1_data->irq_map_mask[idx] |=
                                be32_to_cpup(data->map_mask_prop +
                                             irq * data->n_words + idx);
                } else {
                        l1_data->irq_map_mask[idx] = 0xffffffff;
                }
                valid_mask[idx] |= l1_data->irq_map_mask[idx];
        }

        l1_data->b = data;

        irq_set_chained_handler_and_data(parent_irq,
                                         bcm7120_l2_intc_irq_handle, l1_data);
        if (data->can_wake)
                enable_irq_wake(parent_irq);

        return 0;
}

static int __init bcm7120_l2_intc_iomap_7120(struct device_node *dn,
                                             struct bcm7120_l2_intc_data *data)
{
        int ret;

        data->map_base[0] = of_iomap(dn, 0);
        if (!data->map_base[0]) {
                pr_err("unable to map registers\n");
                return -ENOMEM;
        }

        data->pair_base[0] = data->map_base[0];
        data->en_offset[0] = IRQEN;
        data->stat_offset[0] = IRQSTAT;
        data->n_words = 1;

        ret = of_property_read_u32_array(dn, "brcm,int-fwd-mask",
                                         data->irq_fwd_mask, data->n_words);
        if (ret != 0 && ret != -EINVAL) {
                /* property exists but has the wrong number of words */
                pr_err("invalid brcm,int-fwd-mask property\n");
                return -EINVAL;
        }

        data->map_mask_prop = of_get_property(dn, "brcm,int-map-mask", &ret);
        if (!data->map_mask_prop ||
            (ret != (sizeof(__be32) * data->num_parent_irqs * data->n_words))) {
                pr_err("invalid brcm,int-map-mask property\n");
                return -EINVAL;
        }

        return 0;
}

static int __init bcm7120_l2_intc_iomap_3380(struct device_node *dn,
                                             struct bcm7120_l2_intc_data *data)
{
        unsigned int gc_idx;

        for (gc_idx = 0; gc_idx < MAX_WORDS; gc_idx++) {
                unsigned int map_idx = gc_idx * 2;
                void __iomem *en = of_iomap(dn, map_idx + 0);
                void __iomem *stat = of_iomap(dn, map_idx + 1);
                void __iomem *base = min(en, stat);

                data->map_base[map_idx + 0] = en;
                data->map_base[map_idx + 1] = stat;

                if (!base)
                        break;

                data->pair_base[gc_idx] = base;
                data->en_offset[gc_idx] = en - base;
                data->stat_offset[gc_idx] = stat - base;
        }

        if (!gc_idx) {
                pr_err("unable to map registers\n");
                return -EINVAL;
        }

        data->n_words = gc_idx;
        return 0;
}

static int __init bcm7120_l2_intc_probe(struct device_node *dn,
                                 struct device_node *parent,
                                 int (*iomap_regs_fn)(struct device_node *,
                                        struct bcm7120_l2_intc_data *),
                                 const char *intc_name)
{
        unsigned int clr = IRQ_NOREQUEST | IRQ_NOPROBE | IRQ_NOAUTOEN;
        struct bcm7120_l2_intc_data *data;
        struct irq_chip_generic *gc;
        struct irq_chip_type *ct;
        int ret = 0;
        unsigned int idx, irq, flags;
        u32 valid_mask[MAX_WORDS] = { };

        data = kzalloc(sizeof(*data), GFP_KERNEL);
        if (!data)
                return -ENOMEM;

        data->num_parent_irqs = of_irq_count(dn);
        if (data->num_parent_irqs <= 0) {
                pr_err("invalid number of parent interrupts\n");
                ret = -ENOMEM;
                goto out_unmap;
        }

        data->l1_data = kcalloc(data->num_parent_irqs, sizeof(*data->l1_data),
                                GFP_KERNEL);
        if (!data->l1_data) {
                ret = -ENOMEM;
                goto out_free_l1_data;
        }

        ret = iomap_regs_fn(dn, data);
        if (ret < 0)
                goto out_free_l1_data;

        data->can_wake = of_property_read_bool(dn, "brcm,irq-can-wake");

        for (irq = 0; irq < data->num_parent_irqs; irq++) {
                ret = bcm7120_l2_intc_init_one(dn, data, irq, valid_mask);
                if (ret)
                        goto out_free_l1_data;
        }

        data->domain = irq_domain_add_linear(dn, IRQS_PER_WORD * data->n_words,
                                             &irq_generic_chip_ops, NULL);
        if (!data->domain) {
                ret = -ENOMEM;
                goto out_free_l1_data;
        }

        /* MIPS chips strapped for BE will automagically configure the
         * peripheral registers for CPU-native byte order.
         */
        flags = IRQ_GC_INIT_MASK_CACHE;
        if (IS_ENABLED(CONFIG_MIPS) && IS_ENABLED(CONFIG_CPU_BIG_ENDIAN))
                flags |= IRQ_GC_BE_IO;

        ret = irq_alloc_domain_generic_chips(data->domain, IRQS_PER_WORD, 1,
                                dn->full_name, handle_level_irq, clr, 0, flags);
        if (ret) {
                pr_err("failed to allocate generic irq chip\n");
                goto out_free_domain;
        }

        for (idx = 0; idx < data->n_words; idx++) {
                irq = idx * IRQS_PER_WORD;
                gc = irq_get_domain_generic_chip(data->domain, irq);

                gc->unused = 0xffffffff & ~valid_mask[idx];
                gc->private = data;
                ct = gc->chip_types;

                gc->reg_base = data->pair_base[idx];
                ct->regs.mask = data->en_offset[idx];

                /* gc->reg_base is defined and so is gc->writel */
                irq_reg_writel(gc, data->irq_fwd_mask[idx],
                               data->en_offset[idx]);

                ct->chip.irq_mask = irq_gc_mask_clr_bit;
                ct->chip.irq_unmask = irq_gc_mask_set_bit;
                ct->chip.irq_ack = irq_gc_noop;
                gc->suspend = bcm7120_l2_intc_suspend;
                gc->resume = bcm7120_l2_intc_resume;

                /*
                 * Initialize mask-cache, in case we need it for
                 * saving/restoring fwd mask even w/o any child interrupts
                 * installed
                 */
                gc->mask_cache = irq_reg_readl(gc, ct->regs.mask);

                if (data->can_wake) {
                        /* This IRQ chip can wake the system, set all
                         * relevant child interupts in wake_enabled mask
                         */
                        gc->wake_enabled = 0xffffffff;
                        gc->wake_enabled &= ~gc->unused;
                        ct->chip.irq_set_wake = irq_gc_set_wake;
                }
        }

        pr_info("registered %s intc (%pOF, parent IRQ(s): %d)\n",
                intc_name, dn, data->num_parent_irqs);

        return 0;

out_free_domain:
        irq_domain_remove(data->domain);
out_free_l1_data:
        kfree(data->l1_data);
out_unmap:
        for (idx = 0; idx < MAX_MAPPINGS; idx++) {
                if (data->map_base[idx])
                        iounmap(data->map_base[idx]);
        }
        kfree(data);
        return ret;
}

static int __init bcm7120_l2_intc_probe_7120(struct device_node *dn,
                                             struct device_node *parent)
{
        return bcm7120_l2_intc_probe(dn, parent, bcm7120_l2_intc_iomap_7120,
                                     "BCM7120 L2");
}

static int __init bcm7120_l2_intc_probe_3380(struct device_node *dn,
                                             struct device_node *parent)
{
        return bcm7120_l2_intc_probe(dn, parent, bcm7120_l2_intc_iomap_3380,
                                     "BCM3380 L2");
}

IRQCHIP_DECLARE(bcm7120_l2_intc, "brcm,bcm7120-l2-intc",
                bcm7120_l2_intc_probe_7120);

IRQCHIP_DECLARE(bcm3380_l2_intc, "brcm,bcm3380-l2-intc",
                bcm7120_l2_intc_probe_3380);