root/drivers/irqchip/irq-loongson-liointc.c
// SPDX-License-Identifier: GPL-2.0
/*
 *  Copyright (C) 2020, Jiaxun Yang <jiaxun.yang@flygoat.com>
 *  Loongson Local IO Interrupt Controller support
 */

#include <linux/errno.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/interrupt.h>
#include <linux/ioport.h>
#include <linux/irqchip.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/io.h>
#include <linux/smp.h>
#include <linux/irqchip/chained_irq.h>

#ifdef CONFIG_MIPS
#include <loongson.h>
#else
#include <asm/loongson.h>
#endif

#include "irq-loongson.h"

#define LIOINTC_CHIP_IRQ        32
#define LIOINTC_NUM_PARENT      4
#define LIOINTC_NUM_CORES       4

#define LIOINTC_INTC_CHIP_START 0x20

#define LIOINTC_REG_INTC_STATUS(core)   (LIOINTC_INTC_CHIP_START + 0x20 + (core) * 8)
#define LIOINTC_REG_INTC_EN_STATUS      (LIOINTC_INTC_CHIP_START + 0x04)
#define LIOINTC_REG_INTC_ENABLE (LIOINTC_INTC_CHIP_START + 0x08)
#define LIOINTC_REG_INTC_DISABLE        (LIOINTC_INTC_CHIP_START + 0x0c)
/*
 * LIOINTC_REG_INTC_POL register is only valid for Loongson-2K series, and
 * Loongson-3 series behave as noops.
 */
#define LIOINTC_REG_INTC_POL    (LIOINTC_INTC_CHIP_START + 0x10)
#define LIOINTC_REG_INTC_EDGE   (LIOINTC_INTC_CHIP_START + 0x14)

#define LIOINTC_SHIFT_INTx      4

#define LIOINTC_ERRATA_IRQ      10

#if defined(CONFIG_MIPS)
#define liointc_core_id get_ebase_cpunum()
#else
#define liointc_core_id get_csr_cpuid()
#endif

struct liointc_handler_data {
        struct liointc_priv     *priv;
        u32                     parent_int_map;
};

struct liointc_priv {
        struct irq_chip_generic         *gc;
        struct liointc_handler_data     handler[LIOINTC_NUM_PARENT];
        void __iomem                    *core_isr[LIOINTC_NUM_CORES];
        u8                              map_cache[LIOINTC_CHIP_IRQ];
        u32                             int_pol;
        u32                             int_edge;
        bool                            has_lpc_irq_errata;
};

struct fwnode_handle *liointc_handle;

static void liointc_chained_handle_irq(struct irq_desc *desc)
{
        struct liointc_handler_data *handler = irq_desc_get_handler_data(desc);
        struct irq_chip *chip = irq_desc_get_chip(desc);
        struct irq_chip_generic *gc = handler->priv->gc;
        int core = liointc_core_id % LIOINTC_NUM_CORES;
        u32 pending;

        chained_irq_enter(chip, desc);

        pending = readl(handler->priv->core_isr[core]);

        if (!pending) {
                /* Always blame LPC IRQ if we have that bug */
                if (handler->priv->has_lpc_irq_errata &&
                        (handler->parent_int_map & gc->mask_cache &
                        BIT(LIOINTC_ERRATA_IRQ)))
                        pending = BIT(LIOINTC_ERRATA_IRQ);
                else
                        spurious_interrupt();
        }

        while (pending) {
                int bit = __ffs(pending);

                generic_handle_domain_irq(gc->domain, bit);
                pending &= ~BIT(bit);
        }

        chained_irq_exit(chip, desc);
}

static void liointc_set_bit(struct irq_chip_generic *gc,
                                unsigned int offset,
                                u32 mask, bool set)
{
        if (set)
                writel(readl(gc->reg_base + offset) | mask,
                                gc->reg_base + offset);
        else
                writel(readl(gc->reg_base + offset) & ~mask,
                                gc->reg_base + offset);
}

static int liointc_set_type(struct irq_data *data, unsigned int type)
{
        struct irq_chip_generic *gc = irq_data_get_irq_chip_data(data);
        u32 mask = data->mask;

        guard(raw_spinlock)(&gc->lock);
        switch (type) {
        case IRQ_TYPE_LEVEL_HIGH:
                liointc_set_bit(gc, LIOINTC_REG_INTC_EDGE, mask, false);
                liointc_set_bit(gc, LIOINTC_REG_INTC_POL, mask, false);
                break;
        case IRQ_TYPE_LEVEL_LOW:
                liointc_set_bit(gc, LIOINTC_REG_INTC_EDGE, mask, false);
                liointc_set_bit(gc, LIOINTC_REG_INTC_POL, mask, true);
                break;
        case IRQ_TYPE_EDGE_RISING:
                liointc_set_bit(gc, LIOINTC_REG_INTC_EDGE, mask, true);
                liointc_set_bit(gc, LIOINTC_REG_INTC_POL, mask, false);
                break;
        case IRQ_TYPE_EDGE_FALLING:
                liointc_set_bit(gc, LIOINTC_REG_INTC_EDGE, mask, true);
                liointc_set_bit(gc, LIOINTC_REG_INTC_POL, mask, true);
                break;
        default:
                return -EINVAL;
        }

        irqd_set_trigger_type(data, type);
        return 0;
}

static void liointc_suspend(struct irq_chip_generic *gc)
{
        struct liointc_priv *priv = gc->private;

        priv->int_pol = readl(gc->reg_base + LIOINTC_REG_INTC_POL);
        priv->int_edge = readl(gc->reg_base + LIOINTC_REG_INTC_EDGE);
}

static void liointc_resume(struct irq_chip_generic *gc)
{
        struct liointc_priv *priv = gc->private;
        int i;

        guard(raw_spinlock_irqsave)(&gc->lock);
        /* Disable all at first */
        writel(0xffffffff, gc->reg_base + LIOINTC_REG_INTC_DISABLE);
        /* Restore map cache */
        for (i = 0; i < LIOINTC_CHIP_IRQ; i++)
                writeb(priv->map_cache[i], gc->reg_base + i);
        writel(priv->int_pol, gc->reg_base + LIOINTC_REG_INTC_POL);
        writel(priv->int_edge, gc->reg_base + LIOINTC_REG_INTC_EDGE);
        /* Restore mask cache */
        writel(gc->mask_cache, gc->reg_base + LIOINTC_REG_INTC_ENABLE);
}

static int parent_irq[LIOINTC_NUM_PARENT];
static u32 parent_int_map[LIOINTC_NUM_PARENT];
static const char *const parent_names[] = {"int0", "int1", "int2", "int3"};
static const char *const core_reg_names[] = {"isr0", "isr1", "isr2", "isr3"};

static int liointc_domain_xlate(struct irq_domain *d, struct device_node *ctrlr,
                             const u32 *intspec, unsigned int intsize,
                             unsigned long *out_hwirq, unsigned int *out_type)
{
        if (WARN_ON(intsize < 1))
                return -EINVAL;
        *out_hwirq = intspec[0] - GSI_MIN_CPU_IRQ;

        if (intsize > 1)
                *out_type = intspec[1] & IRQ_TYPE_SENSE_MASK;
        else
                *out_type = IRQ_TYPE_NONE;

        return 0;
}

static const struct irq_domain_ops acpi_irq_gc_ops = {
        .map    = irq_map_generic_chip,
        .unmap  = irq_unmap_generic_chip,
        .xlate  = liointc_domain_xlate,
};

static int liointc_init(phys_addr_t addr, unsigned long size, int revision,
                struct fwnode_handle *domain_handle, struct device_node *node)
{
        int i, err;
        void __iomem *base;
        struct irq_chip_type *ct;
        struct irq_chip_generic *gc;
        struct irq_domain *domain;
        struct liointc_priv *priv;

        priv = kzalloc_obj(*priv);
        if (!priv)
                return -ENOMEM;

        base = ioremap(addr, size);
        if (!base)
                goto out_free_priv;

        for (i = 0; i < LIOINTC_NUM_CORES; i++)
                priv->core_isr[i] = base + LIOINTC_REG_INTC_STATUS(i);

        for (i = 0; i < LIOINTC_NUM_PARENT; i++)
                priv->handler[i].parent_int_map = parent_int_map[i];

        if (revision > 1) {
                for (i = 0; i < LIOINTC_NUM_CORES; i++) {
                        int index = of_property_match_string(node,
                                        "reg-names", core_reg_names[i]);

                        if (index < 0)
                                continue;

                        priv->core_isr[i] = of_iomap(node, index);
                }

                if (!priv->core_isr[0])
                        goto out_iounmap;
        }

        /* Setup IRQ domain */
        if (!acpi_disabled)
                domain = irq_domain_create_linear(domain_handle, LIOINTC_CHIP_IRQ,
                                        &acpi_irq_gc_ops, priv);
        else
                domain = irq_domain_create_linear(domain_handle, LIOINTC_CHIP_IRQ,
                                        &irq_generic_chip_ops, priv);
        if (!domain) {
                pr_err("loongson-liointc: cannot add IRQ domain\n");
                goto out_iounmap;
        }

        err = irq_alloc_domain_generic_chips(domain, LIOINTC_CHIP_IRQ, 1,
                                        (node ? node->full_name : "LIOINTC"),
                                        handle_level_irq, 0, IRQ_NOPROBE, 0);
        if (err) {
                pr_err("loongson-liointc: unable to register IRQ domain\n");
                goto out_free_domain;
        }


        /* Disable all IRQs */
        writel(0xffffffff, base + LIOINTC_REG_INTC_DISABLE);
        /* Set to level triggered */
        writel(0x0, base + LIOINTC_REG_INTC_EDGE);

        /* Generate parent INT part of map cache */
        for (i = 0; i < LIOINTC_NUM_PARENT; i++) {
                u32 pending = priv->handler[i].parent_int_map;

                while (pending) {
                        int bit = __ffs(pending);

                        priv->map_cache[bit] = BIT(i) << LIOINTC_SHIFT_INTx;
                        pending &= ~BIT(bit);
                }
        }

        for (i = 0; i < LIOINTC_CHIP_IRQ; i++) {
                /* Generate core part of map cache */
                priv->map_cache[i] |= BIT(loongson_sysconf.boot_cpu_id);
                writeb(priv->map_cache[i], base + i);
        }

        gc = irq_get_domain_generic_chip(domain, 0);
        gc->private = priv;
        gc->reg_base = base;
        gc->domain = domain;
        gc->suspend = liointc_suspend;
        gc->resume = liointc_resume;

        ct = gc->chip_types;
        ct->regs.enable = LIOINTC_REG_INTC_ENABLE;
        ct->regs.disable = LIOINTC_REG_INTC_DISABLE;
        ct->chip.irq_unmask = irq_gc_unmask_enable_reg;
        ct->chip.irq_mask = irq_gc_mask_disable_reg;
        ct->chip.irq_mask_ack = irq_gc_mask_disable_reg;
        ct->chip.irq_set_type = liointc_set_type;
        ct->chip.flags = IRQCHIP_SKIP_SET_WAKE;

        gc->mask_cache = 0;
        priv->gc = gc;

        for (i = 0; i < LIOINTC_NUM_PARENT; i++) {
                if (parent_irq[i] <= 0)
                        continue;

                priv->handler[i].priv = priv;
                irq_set_chained_handler_and_data(parent_irq[i],
                                liointc_chained_handle_irq, &priv->handler[i]);
        }

        liointc_handle = domain_handle;
        return 0;

out_free_domain:
        irq_domain_remove(domain);
out_iounmap:
        iounmap(base);
out_free_priv:
        kfree(priv);

        return -EINVAL;
}

#ifdef CONFIG_OF

static int __init liointc_of_init(struct device_node *node,
                                  struct device_node *parent)
{
        bool have_parent = FALSE;
        int sz, i, index, revision, err = 0;
        struct resource res;

        if (!of_device_is_compatible(node, "loongson,liointc-2.0")) {
                index = 0;
                revision = 1;
        } else {
                index = of_property_match_string(node, "reg-names", "main");
                revision = 2;
        }

        if (of_address_to_resource(node, index, &res))
                return -EINVAL;

        for (i = 0; i < LIOINTC_NUM_PARENT; i++) {
                parent_irq[i] = of_irq_get_byname(node, parent_names[i]);
                if (parent_irq[i] > 0)
                        have_parent = TRUE;
        }
        if (!have_parent)
                return -ENODEV;

        sz = of_property_read_variable_u32_array(node,
                                                "loongson,parent_int_map",
                                                &parent_int_map[0],
                                                LIOINTC_NUM_PARENT,
                                                LIOINTC_NUM_PARENT);
        if (sz < 4) {
                pr_err("loongson-liointc: No parent_int_map\n");
                return -ENODEV;
        }

        err = liointc_init(res.start, resource_size(&res),
                        revision, of_fwnode_handle(node), node);
        if (err < 0)
                return err;

        return 0;
}

IRQCHIP_DECLARE(loongson_liointc_1_0, "loongson,liointc-1.0", liointc_of_init);
IRQCHIP_DECLARE(loongson_liointc_1_0a, "loongson,liointc-1.0a", liointc_of_init);
IRQCHIP_DECLARE(loongson_liointc_2_0, "loongson,liointc-2.0", liointc_of_init);

#endif

#ifdef CONFIG_ACPI
static int __init htintc_parse_madt(union acpi_subtable_headers *header,
                                        const unsigned long end)
{
        struct acpi_madt_ht_pic *htintc_entry = (struct acpi_madt_ht_pic *)header;
        struct irq_domain *parent = irq_find_matching_fwnode(liointc_handle, DOMAIN_BUS_ANY);

        return htvec_acpi_init(parent, htintc_entry);
}

static int __init acpi_cascade_irqdomain_init(void)
{
        int r;

        r = acpi_table_parse_madt(ACPI_MADT_TYPE_HT_PIC, htintc_parse_madt, 0);
        if (r < 0)
                return r;

        return 0;
}

int __init liointc_acpi_init(struct irq_domain *parent, struct acpi_madt_lio_pic *acpi_liointc)
{
        phys_addr_t addr = (phys_addr_t)acpi_liointc->address;
        struct fwnode_handle *domain_handle;
        int ret;

        parent_int_map[0] = acpi_liointc->cascade_map[0];
        parent_int_map[1] = acpi_liointc->cascade_map[1];

        parent_irq[0] = irq_create_mapping(parent, acpi_liointc->cascade[0]);
        parent_irq[1] = irq_create_mapping(parent, acpi_liointc->cascade[1]);

        domain_handle = irq_domain_alloc_fwnode(&addr);
        if (!domain_handle) {
                pr_err("Unable to allocate domain handle\n");
                return -ENOMEM;
        }

        ret = liointc_init(addr, acpi_liointc->size, 1, domain_handle, NULL);
        if (ret == 0)
                ret = acpi_cascade_irqdomain_init();
        else
                irq_domain_free_fwnode(domain_handle);

        return ret;
}
#endif