root/drivers/irqchip/irq-keystone.c
// SPDX-License-Identifier: GPL-2.0-only
/*
 * Texas Instruments Keystone IRQ controller IP driver
 *
 * Copyright (C) 2014 Texas Instruments, Inc.
 * Author: Sajesh Kumar Saran <sajesh@ti.com>
 *         Grygorii Strashko <grygorii.strashko@ti.com>
 */

#include <linux/irq.h>
#include <linux/bitops.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/interrupt.h>
#include <linux/irqdomain.h>
#include <linux/irqchip.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/mfd/syscon.h>
#include <linux/regmap.h>

/* The source ID bits start from 4 to 31 (total 28 bits)*/
#define BIT_OFS                 4
#define KEYSTONE_N_IRQ          (32 - BIT_OFS)

struct keystone_irq_device {
        struct device           *dev;
        struct irq_chip          chip;
        u32                      mask;
        int                      irq;
        struct irq_domain       *irqd;
        struct regmap           *devctrl_regs;
        u32                     devctrl_offset;
        raw_spinlock_t          wa_lock;
};

static inline u32 keystone_irq_readl(struct keystone_irq_device *kirq)
{
        int ret;
        u32 val = 0;

        ret = regmap_read(kirq->devctrl_regs, kirq->devctrl_offset, &val);
        if (ret < 0)
                dev_dbg(kirq->dev, "irq read failed ret(%d)\n", ret);
        return val;
}

static inline void
keystone_irq_writel(struct keystone_irq_device *kirq, u32 value)
{
        int ret;

        ret = regmap_write(kirq->devctrl_regs, kirq->devctrl_offset, value);
        if (ret < 0)
                dev_dbg(kirq->dev, "irq write failed ret(%d)\n", ret);
}

static void keystone_irq_setmask(struct irq_data *d)
{
        struct keystone_irq_device *kirq = irq_data_get_irq_chip_data(d);

        kirq->mask |= BIT(d->hwirq);
        dev_dbg(kirq->dev, "mask %lu [%x]\n", d->hwirq, kirq->mask);
}

static void keystone_irq_unmask(struct irq_data *d)
{
        struct keystone_irq_device *kirq = irq_data_get_irq_chip_data(d);

        kirq->mask &= ~BIT(d->hwirq);
        dev_dbg(kirq->dev, "unmask %lu [%x]\n", d->hwirq, kirq->mask);
}

static void keystone_irq_ack(struct irq_data *d)
{
        /* nothing to do here */
}

static irqreturn_t keystone_irq_handler(int irq, void *keystone_irq)
{
        struct keystone_irq_device *kirq = keystone_irq;
        unsigned long wa_lock_flags;
        unsigned long pending;
        int src, err;

        dev_dbg(kirq->dev, "start irq %d\n", irq);

        pending = keystone_irq_readl(kirq);
        keystone_irq_writel(kirq, pending);

        dev_dbg(kirq->dev, "pending 0x%lx, mask 0x%x\n", pending, kirq->mask);

        pending = (pending >> BIT_OFS) & ~kirq->mask;

        dev_dbg(kirq->dev, "pending after mask 0x%lx\n", pending);

        for (src = 0; src < KEYSTONE_N_IRQ; src++) {
                if (BIT(src) & pending) {
                        raw_spin_lock_irqsave(&kirq->wa_lock, wa_lock_flags);
                        err = generic_handle_domain_irq(kirq->irqd, src);
                        raw_spin_unlock_irqrestore(&kirq->wa_lock,
                                                   wa_lock_flags);

                        if (err)
                                dev_warn_ratelimited(kirq->dev, "spurious irq detected hwirq %d\n",
                                                     src);
                }
        }

        dev_dbg(kirq->dev, "end irq %d\n", irq);
        return IRQ_HANDLED;
}

static int keystone_irq_map(struct irq_domain *h, unsigned int virq,
                                irq_hw_number_t hw)
{
        struct keystone_irq_device *kirq = h->host_data;

        irq_set_chip_data(virq, kirq);
        irq_set_chip_and_handler(virq, &kirq->chip, handle_level_irq);
        irq_set_probe(virq);
        return 0;
}

static const struct irq_domain_ops keystone_irq_ops = {
        .map    = keystone_irq_map,
        .xlate  = irq_domain_xlate_onecell,
};

static int keystone_irq_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct device_node *np = dev->of_node;
        struct keystone_irq_device *kirq;
        int ret;

        if (np == NULL)
                return -EINVAL;

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

        kirq->devctrl_regs = syscon_regmap_lookup_by_phandle_args(np, "ti,syscon-dev",
                                                                  1, &kirq->devctrl_offset);
        if (IS_ERR(kirq->devctrl_regs))
                return PTR_ERR(kirq->devctrl_regs);

        kirq->irq = platform_get_irq(pdev, 0);
        if (kirq->irq < 0)
                return kirq->irq;

        kirq->dev = dev;
        kirq->mask = ~0x0;
        kirq->chip.name         = "keystone-irq";
        kirq->chip.irq_ack      = keystone_irq_ack;
        kirq->chip.irq_mask     = keystone_irq_setmask;
        kirq->chip.irq_unmask   = keystone_irq_unmask;

        kirq->irqd = irq_domain_create_linear(dev_fwnode(dev), KEYSTONE_N_IRQ, &keystone_irq_ops,
                                              kirq);
        if (!kirq->irqd) {
                dev_err(dev, "IRQ domain registration failed\n");
                return -ENODEV;
        }

        raw_spin_lock_init(&kirq->wa_lock);

        platform_set_drvdata(pdev, kirq);

        ret = request_irq(kirq->irq, keystone_irq_handler,
                          0, dev_name(dev), kirq);
        if (ret) {
                irq_domain_remove(kirq->irqd);
                return ret;
        }

        /* clear all source bits */
        keystone_irq_writel(kirq, ~0x0);

        dev_info(dev, "irqchip registered, nr_irqs %u\n", KEYSTONE_N_IRQ);

        return 0;
}

static void keystone_irq_remove(struct platform_device *pdev)
{
        struct keystone_irq_device *kirq = platform_get_drvdata(pdev);
        int hwirq;

        free_irq(kirq->irq, kirq);

        for (hwirq = 0; hwirq < KEYSTONE_N_IRQ; hwirq++)
                irq_dispose_mapping(irq_find_mapping(kirq->irqd, hwirq));

        irq_domain_remove(kirq->irqd);
}

static const struct of_device_id keystone_irq_dt_ids[] = {
        { .compatible = "ti,keystone-irq", },
        {},
};
MODULE_DEVICE_TABLE(of, keystone_irq_dt_ids);

static struct platform_driver keystone_irq_device_driver = {
        .probe          = keystone_irq_probe,
        .remove         = keystone_irq_remove,
        .driver         = {
                .name   = "keystone_irq",
                .of_match_table = of_match_ptr(keystone_irq_dt_ids),
        }
};

module_platform_driver(keystone_irq_device_driver);

MODULE_AUTHOR("Texas Instruments");
MODULE_AUTHOR("Sajesh Kumar Saran");
MODULE_AUTHOR("Grygorii Strashko");
MODULE_DESCRIPTION("Keystone IRQ chip");
MODULE_LICENSE("GPL v2");