// SPDX-License-Identifier: GPL-2.0
/*
 * Texas Instruments' K3 Interrupt Router irqchip driver
 *
 * Copyright (C) 2018-2019 Texas Instruments Incorporated - https://www.ti.com/
 *      Lokesh Vutla <lokeshvutla@ti.com>
 */

#include <linux/err.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/io.h>
#include <linux/irqchip.h>
#include <linux/irqdomain.h>
#include <linux/of.h>
#include <linux/of_irq.h>
#include <linux/platform_device.h>
#include <linux/soc/ti/ti_sci_protocol.h>

/**
 * struct ti_sci_intr_irq_domain - Structure representing a TISCI based
 *                                 Interrupt Router IRQ domain.
 * @sci:        Pointer to TISCI handle
 * @out_irqs:   TISCI resource pointer representing INTR irqs.
 * @dev:        Struct device pointer.
 * @ti_sci_id:  TI-SCI device identifier
 * @type:       Specifies the trigger type supported by this Interrupt Router
 */
struct ti_sci_intr_irq_domain {
        const struct ti_sci_handle *sci;
        struct ti_sci_resource *out_irqs;
        struct device *dev;
        u32 ti_sci_id;
        u32 type;
};

static struct irq_chip ti_sci_intr_irq_chip = {
        .name                   = "INTR",
        .irq_eoi                = irq_chip_eoi_parent,
        .irq_mask               = irq_chip_mask_parent,
        .irq_unmask             = irq_chip_unmask_parent,
        .irq_set_type           = irq_chip_set_type_parent,
        .irq_retrigger          = irq_chip_retrigger_hierarchy,
        .irq_set_affinity       = irq_chip_set_affinity_parent,
};

/**
 * ti_sci_intr_irq_domain_translate() - Retrieve hwirq and type from
 *                                      IRQ firmware specific handler.
 * @domain:     Pointer to IRQ domain
 * @fwspec:     Pointer to IRQ specific firmware structure
 * @hwirq:      IRQ number identified by hardware
 * @type:       IRQ type
 *
 * Return 0 if all went ok else appropriate error.
 */
static int ti_sci_intr_irq_domain_translate(struct irq_domain *domain,
                                            struct irq_fwspec *fwspec,
                                            unsigned long *hwirq,
                                            unsigned int *type)
{
        struct ti_sci_intr_irq_domain *intr = domain->host_data;

        if (intr->type) {
                /* Global interrupt-type */
                if (fwspec->param_count != 1)
                        return -EINVAL;

                *hwirq = fwspec->param[0];
                *type = intr->type;
        } else {
                /* Per-Line interrupt-type */
                if (fwspec->param_count != 2)
                        return -EINVAL;

                *hwirq = fwspec->param[0];
                *type = fwspec->param[1];
        }
        return 0;
}

/**
 * ti_sci_intr_xlate_irq() - Translate hwirq to parent's hwirq.
 * @intr:       IRQ domain corresponding to Interrupt Router
 * @irq:        Hardware irq corresponding to the above irq domain
 *
 * Return parent irq number if translation is available else -ENOENT.
 */
static int ti_sci_intr_xlate_irq(struct ti_sci_intr_irq_domain *intr, u32 irq)
{
        struct device_node *np = dev_of_node(intr->dev);
        u32 base, pbase, size, len;
        const __be32 *range;

        range = of_get_property(np, "ti,interrupt-ranges", &len);
        if (!range)
                return irq;

        for (len /= sizeof(*range); len >= 3; len -= 3) {
                base = be32_to_cpu(*range++);
                pbase = be32_to_cpu(*range++);
                size = be32_to_cpu(*range++);

                if (base <= irq && irq < base + size)
                        return irq - base + pbase;
        }

        return -ENOENT;
}

/**
 * ti_sci_intr_irq_domain_free() - Free the specified IRQs from the domain.
 * @domain:     Domain to which the irqs belong
 * @virq:       Linux virtual IRQ to be freed.
 * @nr_irqs:    Number of continuous irqs to be freed
 */
static void ti_sci_intr_irq_domain_free(struct irq_domain *domain,
                                        unsigned int virq, unsigned int nr_irqs)
{
        struct ti_sci_intr_irq_domain *intr = domain->host_data;
        struct irq_data *data;
        int out_irq;

        data = irq_domain_get_irq_data(domain, virq);
        out_irq = (uintptr_t)data->chip_data;

        intr->sci->ops.rm_irq_ops.free_irq(intr->sci,
                                           intr->ti_sci_id, data->hwirq,
                                           intr->ti_sci_id, out_irq);
        ti_sci_release_resource(intr->out_irqs, out_irq);
        irq_domain_free_irqs_parent(domain, virq, 1);
        irq_domain_reset_irq_data(data);
}

/**
 * ti_sci_intr_alloc_parent_irq() - Allocate parent IRQ
 * @domain:     Pointer to the interrupt router IRQ domain
 * @virq:       Corresponding Linux virtual IRQ number
 * @hwirq:      Corresponding hwirq for the IRQ within this IRQ domain
 * @hwirq_type: Corresponding hwirq trigger type for the IRQ within this IRQ domain
 *
 * Returns intr output irq if all went well else appropriate error pointer.
 */
static int ti_sci_intr_alloc_parent_irq(struct irq_domain *domain, unsigned int virq,
                                        u32 hwirq, u32 hwirq_type)
{
        struct ti_sci_intr_irq_domain *intr = domain->host_data;
        struct device_node *parent_node;
        struct irq_fwspec fwspec;
        int p_hwirq, err = 0;
        u16 out_irq;

        out_irq = ti_sci_get_free_resource(intr->out_irqs);
        if (out_irq == TI_SCI_RESOURCE_NULL)
                return -EINVAL;

        p_hwirq = ti_sci_intr_xlate_irq(intr, out_irq);
        if (p_hwirq < 0)
                goto err_irqs;

        parent_node = of_irq_find_parent(dev_of_node(intr->dev));
        fwspec.fwnode = of_fwnode_handle(parent_node);

        if (of_device_is_compatible(parent_node, "arm,gic-v3")) {
                /* Parent is GIC */
                fwspec.param_count = 3;
                fwspec.param[0] = 0;    /* SPI */
                fwspec.param[1] = p_hwirq - 32; /* SPI offset */
                fwspec.param[2] = hwirq_type;
        } else {
                /* Parent is Interrupt Router */
                u32 parent_trigger_type;

                if (!of_property_read_u32(parent_node, "ti,intr-trigger-type",
                                          &parent_trigger_type)) {
                        /* Parent has global trigger type */
                        fwspec.param_count = 1;
                        fwspec.param[0] = p_hwirq;
                } else {
                        /* Parent supports per-line trigger types */
                        fwspec.param_count = 2;
                        fwspec.param[0] = p_hwirq;
                        fwspec.param[1] = hwirq_type;
                }
        }

        err = irq_domain_alloc_irqs_parent(domain, virq, 1, &fwspec);
        if (err)
                goto err_irqs;

        err = intr->sci->ops.rm_irq_ops.set_irq(intr->sci,
                                                intr->ti_sci_id, hwirq,
                                                intr->ti_sci_id, out_irq);
        if (err)
                goto err_msg;

        return out_irq;

err_msg:
        irq_domain_free_irqs_parent(domain, virq, 1);
err_irqs:
        ti_sci_release_resource(intr->out_irqs, out_irq);
        return err;
}

/**
 * ti_sci_intr_irq_domain_alloc() - Allocate Interrupt router IRQs
 * @domain:     Point to the interrupt router IRQ domain
 * @virq:       Corresponding Linux virtual IRQ number
 * @nr_irqs:    Continuous irqs to be allocated
 * @data:       Pointer to firmware specifier
 *
 * Return 0 if all went well else appropriate error value.
 */
static int ti_sci_intr_irq_domain_alloc(struct irq_domain *domain,
                                        unsigned int virq, unsigned int nr_irqs,
                                        void *data)
{
        struct irq_fwspec *fwspec = data;
        unsigned int hwirq_type;
        unsigned long hwirq;
        int err, out_irq;

        err = ti_sci_intr_irq_domain_translate(domain, fwspec, &hwirq, &hwirq_type);
        if (err)
                return err;

        out_irq = ti_sci_intr_alloc_parent_irq(domain, virq, hwirq, hwirq_type);
        if (out_irq < 0)
                return out_irq;

        irq_domain_set_hwirq_and_chip(domain, virq, hwirq,
                                      &ti_sci_intr_irq_chip,
                                      (void *)(uintptr_t)out_irq);

        return 0;
}

static const struct irq_domain_ops ti_sci_intr_irq_domain_ops = {
        .free           = ti_sci_intr_irq_domain_free,
        .alloc          = ti_sci_intr_irq_domain_alloc,
        .translate      = ti_sci_intr_irq_domain_translate,
};

static int ti_sci_intr_irq_domain_probe(struct platform_device *pdev)
{
        struct irq_domain *parent_domain, *domain;
        struct ti_sci_intr_irq_domain *intr;
        struct device_node *parent_node;
        struct device *dev = &pdev->dev;
        int ret;

        parent_node = of_irq_find_parent(dev_of_node(dev));
        if (!parent_node) {
                dev_err(dev, "Failed to get IRQ parent node\n");
                return -ENODEV;
        }

        parent_domain = irq_find_host(parent_node);
        of_node_put(parent_node);
        if (!parent_domain) {
                dev_err(dev, "Failed to find IRQ parent domain\n");
                return -ENODEV;
        }

        intr = devm_kzalloc(dev, sizeof(*intr), GFP_KERNEL);
        if (!intr)
                return -ENOMEM;

        intr->dev = dev;

        if (of_property_read_u32(dev_of_node(dev), "ti,intr-trigger-type", &intr->type))
                intr->type = IRQ_TYPE_NONE;

        intr->sci = devm_ti_sci_get_by_phandle(dev, "ti,sci");
        if (IS_ERR(intr->sci))
                return dev_err_probe(dev, PTR_ERR(intr->sci),
                                     "ti,sci read fail\n");

        ret = of_property_read_u32(dev_of_node(dev), "ti,sci-dev-id",
                                   &intr->ti_sci_id);
        if (ret) {
                dev_err(dev, "missing 'ti,sci-dev-id' property\n");
                return -EINVAL;
        }

        intr->out_irqs = devm_ti_sci_get_resource(intr->sci, dev,
                                                  intr->ti_sci_id,
                                                  TI_SCI_RESASG_SUBTYPE_IR_OUTPUT);
        if (IS_ERR(intr->out_irqs)) {
                dev_err(dev, "Destination irq resource allocation failed\n");
                return PTR_ERR(intr->out_irqs);
        }

        domain = irq_domain_create_hierarchy(parent_domain, 0, 0, dev_fwnode(dev),
                                             &ti_sci_intr_irq_domain_ops, intr);
        if (!domain) {
                dev_err(dev, "Failed to allocate IRQ domain\n");
                return -ENOMEM;
        }

        dev_info(dev, "Interrupt Router %d domain created\n", intr->ti_sci_id);

        return 0;
}

static const struct of_device_id ti_sci_intr_irq_domain_of_match[] = {
        { .compatible = "ti,sci-intr", },
        { /* sentinel */ },
};
MODULE_DEVICE_TABLE(of, ti_sci_intr_irq_domain_of_match);

static struct platform_driver ti_sci_intr_irq_domain_driver = {
        .probe = ti_sci_intr_irq_domain_probe,
        .driver = {
                .name = "ti-sci-intr",
                .of_match_table = ti_sci_intr_irq_domain_of_match,
        },
};
module_platform_driver(ti_sci_intr_irq_domain_driver);

MODULE_AUTHOR("Lokesh Vutla <lokeshvutla@ticom>");
MODULE_DESCRIPTION("K3 Interrupt Router driver over TI SCI protocol");
MODULE_LICENSE("GPL");