// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
 */

#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/irqchip.h>
#include <linux/irqdomain.h>

#include <asm/loongarch.h>
#include <asm/setup.h>

#include "irq-loongson.h"

static struct irq_domain *irq_domain;
struct fwnode_handle *cpuintc_handle;

static u32 lpic_gsi_to_irq(u32 gsi)
{
        int irq = 0;

        /* Only pch irqdomain transferring is required for LoongArch. */
        if (gsi >= GSI_MIN_PCH_IRQ && gsi <= GSI_MAX_PCH_IRQ)
                irq = acpi_register_gsi(NULL, gsi, ACPI_LEVEL_SENSITIVE, ACPI_ACTIVE_HIGH);

        return (irq > 0) ? irq : 0;
}

static struct fwnode_handle *lpic_get_gsi_domain_id(u32 gsi)
{
        int id;
        struct fwnode_handle *domain_handle = NULL;

        switch (gsi) {
        case GSI_MIN_CPU_IRQ ... GSI_MAX_CPU_IRQ:
                if (liointc_handle)
                        domain_handle = liointc_handle;
                break;

        case GSI_MIN_LPC_IRQ ... GSI_MAX_LPC_IRQ:
                if (pch_lpc_handle)
                        domain_handle = pch_lpc_handle;
                break;

        case GSI_MIN_PCH_IRQ ... GSI_MAX_PCH_IRQ:
                id = find_pch_pic(gsi);
                if (id >= 0 && pch_pic_handle[id])
                        domain_handle = pch_pic_handle[id];
                break;
        }

        return domain_handle;
}

static void mask_loongarch_irq(struct irq_data *d)
{
        clear_csr_ecfg(ECFGF(d->hwirq));
}

static void unmask_loongarch_irq(struct irq_data *d)
{
        set_csr_ecfg(ECFGF(d->hwirq));
}

static struct irq_chip cpu_irq_controller = {
        .name           = "CPUINTC",
        .irq_mask       = mask_loongarch_irq,
        .irq_unmask     = unmask_loongarch_irq,
};

static void handle_cpu_irq(struct pt_regs *regs)
{
        int hwirq;
        unsigned int estat = read_csr_estat() & CSR_ESTAT_IS;

        while ((hwirq = ffs(estat))) {
                estat &= ~BIT(hwirq - 1);
                generic_handle_domain_irq(irq_domain, hwirq - 1);
        }
}

static int loongarch_cpu_intc_map(struct irq_domain *d, unsigned int irq,
                             irq_hw_number_t hwirq)
{
        irq_set_noprobe(irq);
        irq_set_chip_and_handler(irq, &cpu_irq_controller, handle_percpu_irq);

        return 0;
}

static const struct irq_domain_ops loongarch_cpu_intc_irq_domain_ops = {
        .map = loongarch_cpu_intc_map,
        .xlate = irq_domain_xlate_onecell,
};

#ifdef CONFIG_OF
static int __init cpuintc_of_init(struct device_node *of_node,
                                struct device_node *parent)
{
        cpuintc_handle = of_fwnode_handle(of_node);

        irq_domain = irq_domain_create_linear(cpuintc_handle, EXCCODE_INT_NUM,
                                &loongarch_cpu_intc_irq_domain_ops, NULL);
        if (!irq_domain)
                panic("Failed to add irqdomain for loongarch CPU");

        set_handle_irq(&handle_cpu_irq);

        return 0;
}
IRQCHIP_DECLARE(cpu_intc, "loongson,cpu-interrupt-controller", cpuintc_of_init);
#endif

static int __init liointc_parse_madt(union acpi_subtable_headers *header,
                                        const unsigned long end)
{
        struct acpi_madt_lio_pic *liointc_entry = (struct acpi_madt_lio_pic *)header;

        return liointc_acpi_init(irq_domain, liointc_entry);
}

static int __init eiointc_parse_madt(union acpi_subtable_headers *header,
                                        const unsigned long end)
{
        struct acpi_madt_eio_pic *eiointc_entry = (struct acpi_madt_eio_pic *)header;

        return eiointc_acpi_init(irq_domain, eiointc_entry);
}

static int __init acpi_cascade_irqdomain_init(void)
{
        int r;

        r = acpi_table_parse_madt(ACPI_MADT_TYPE_LIO_PIC, liointc_parse_madt, 0);
        if (r < 0)
                return r;

        r = acpi_table_parse_madt(ACPI_MADT_TYPE_EIO_PIC, eiointc_parse_madt, 0);
        if (r < 0)
                return r;

        if (cpu_has_avecint)
                r = avecintc_acpi_init(irq_domain);

        return r;
}

static int __init cpuintc_acpi_init(union acpi_subtable_headers *header,
                                   const unsigned long end)
{
        int ret;

        if (irq_domain)
                return 0;

        /* Mask interrupts. */
        clear_csr_ecfg(ECFG0_IM);
        clear_csr_estat(ESTATF_IP);

        cpuintc_handle = irq_domain_alloc_named_fwnode("CPUINTC");
        irq_domain = irq_domain_create_linear(cpuintc_handle, EXCCODE_INT_NUM,
                                        &loongarch_cpu_intc_irq_domain_ops, NULL);

        if (!irq_domain)
                panic("Failed to add irqdomain for LoongArch CPU");

        set_handle_irq(&handle_cpu_irq);
        acpi_set_irq_model(ACPI_IRQ_MODEL_LPIC, lpic_get_gsi_domain_id);
        acpi_set_gsi_to_irq_fallback(lpic_gsi_to_irq);
        ret = acpi_cascade_irqdomain_init();

        return ret;
}

IRQCHIP_ACPI_DECLARE(cpuintc_v1, ACPI_MADT_TYPE_CORE_PIC,
                NULL, ACPI_MADT_CORE_PIC_VERSION_V1, cpuintc_acpi_init);