root/drivers/irqchip/irq-imx-intmux.c
// SPDX-License-Identifier: GPL-2.0
// Copyright 2017 NXP

/*                     INTMUX Block Diagram
 *
 *                               ________________
 * interrupt source #  0  +---->|                |
 *                        |     |                |
 * interrupt source #  1  +++-->|                |
 *            ...         | |   |   channel # 0  |--------->interrupt out # 0
 *            ...         | |   |                |
 *            ...         | |   |                |
 * interrupt source # X-1 +++-->|________________|
 *                        | | |
 *                        | | |
 *                        | | |  ________________
 *                        +---->|                |
 *                        | | | |                |
 *                        | +-->|                |
 *                        | | | |   channel # 1  |--------->interrupt out # 1
 *                        | | +>|                |
 *                        | | | |                |
 *                        | | | |________________|
 *                        | | |
 *                        | | |
 *                        | | |       ...
 *                        | | |       ...
 *                        | | |
 *                        | | |  ________________
 *                        +---->|                |
 *                          | | |                |
 *                          +-->|                |
 *                            | |   channel # N  |--------->interrupt out # N
 *                            +>|                |
 *                              |                |
 *                              |________________|
 *
 *
 * N: Interrupt Channel Instance Number (N=7)
 * X: Interrupt Source Number for each channel (X=32)
 *
 * The INTMUX interrupt multiplexer has 8 channels, each channel receives 32
 * interrupt sources and generates 1 interrupt output.
 *
 */

#include <linux/clk.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/irqchip/chained_irq.h>
#include <linux/irqdomain.h>
#include <linux/kernel.h>
#include <linux/mod_devicetable.h>
#include <linux/of_irq.h>
#include <linux/platform_device.h>
#include <linux/spinlock.h>
#include <linux/pm_runtime.h>

#define CHANIER(n)      (0x10 + (0x40 * n))
#define CHANIPR(n)      (0x20 + (0x40 * n))

#define CHAN_MAX_NUM            0x8

struct intmux_irqchip_data {
        u32                     saved_reg;
        int                     chanidx;
        int                     irq;
        struct irq_domain       *domain;
};

struct intmux_data {
        raw_spinlock_t                  lock;
        void __iomem                    *regs;
        struct clk                      *ipg_clk;
        int                             channum;
        struct intmux_irqchip_data      irqchip_data[] __counted_by(channum);
};

static void imx_intmux_irq_mask(struct irq_data *d)
{
        struct intmux_irqchip_data *irqchip_data = d->chip_data;
        int idx = irqchip_data->chanidx;
        struct intmux_data *data = container_of(irqchip_data, struct intmux_data,
                                                irqchip_data[idx]);
        unsigned long flags;
        void __iomem *reg;
        u32 val;

        raw_spin_lock_irqsave(&data->lock, flags);
        reg = data->regs + CHANIER(idx);
        val = readl_relaxed(reg);
        /* disable the interrupt source of this channel */
        val &= ~BIT(d->hwirq);
        writel_relaxed(val, reg);
        raw_spin_unlock_irqrestore(&data->lock, flags);
}

static void imx_intmux_irq_unmask(struct irq_data *d)
{
        struct intmux_irqchip_data *irqchip_data = d->chip_data;
        int idx = irqchip_data->chanidx;
        struct intmux_data *data = container_of(irqchip_data, struct intmux_data,
                                                irqchip_data[idx]);
        unsigned long flags;
        void __iomem *reg;
        u32 val;

        raw_spin_lock_irqsave(&data->lock, flags);
        reg = data->regs + CHANIER(idx);
        val = readl_relaxed(reg);
        /* enable the interrupt source of this channel */
        val |= BIT(d->hwirq);
        writel_relaxed(val, reg);
        raw_spin_unlock_irqrestore(&data->lock, flags);
}

static struct irq_chip imx_intmux_irq_chip __ro_after_init = {
        .name           = "intmux",
        .irq_mask       = imx_intmux_irq_mask,
        .irq_unmask     = imx_intmux_irq_unmask,
};

static int imx_intmux_irq_map(struct irq_domain *h, unsigned int irq,
                              irq_hw_number_t hwirq)
{
        struct intmux_irqchip_data *data = h->host_data;

        irq_set_chip_data(irq, data);
        irq_set_chip_and_handler(irq, &imx_intmux_irq_chip, handle_level_irq);

        return 0;
}

static int imx_intmux_irq_xlate(struct irq_domain *d, struct device_node *node,
                                const u32 *intspec, unsigned int intsize,
                                unsigned long *out_hwirq, unsigned int *out_type)
{
        struct intmux_irqchip_data *irqchip_data = d->host_data;
        int idx = irqchip_data->chanidx;
        struct intmux_data *data = container_of(irqchip_data, struct intmux_data,
                                                irqchip_data[idx]);

        /*
         * two cells needed in interrupt specifier:
         * the 1st cell: hw interrupt number
         * the 2nd cell: channel index
         */
        if (WARN_ON(intsize != 2))
                return -EINVAL;

        if (WARN_ON(intspec[1] >= data->channum))
                return -EINVAL;

        *out_hwirq = intspec[0];
        *out_type = IRQ_TYPE_LEVEL_HIGH;

        return 0;
}

static int imx_intmux_irq_select(struct irq_domain *d, struct irq_fwspec *fwspec,
                                 enum irq_domain_bus_token bus_token)
{
        struct intmux_irqchip_data *irqchip_data = d->host_data;

        /* Not for us */
        if (fwspec->fwnode != d->fwnode)
                return false;

        /* Handle pure domain searches */
        if (!fwspec->param_count)
                return d->bus_token == bus_token;

        return irqchip_data->chanidx == fwspec->param[1];
}

static const struct irq_domain_ops imx_intmux_domain_ops = {
        .map            = imx_intmux_irq_map,
        .xlate          = imx_intmux_irq_xlate,
        .select         = imx_intmux_irq_select,
};

static void imx_intmux_irq_handler(struct irq_desc *desc)
{
        struct intmux_irqchip_data *irqchip_data = irq_desc_get_handler_data(desc);
        int idx = irqchip_data->chanidx;
        struct intmux_data *data = container_of(irqchip_data, struct intmux_data,
                                                irqchip_data[idx]);
        unsigned long irqstat;
        int pos;

        chained_irq_enter(irq_desc_get_chip(desc), desc);

        /* read the interrupt source pending status of this channel */
        irqstat = readl_relaxed(data->regs + CHANIPR(idx));

        for_each_set_bit(pos, &irqstat, 32)
                generic_handle_domain_irq(irqchip_data->domain, pos);

        chained_irq_exit(irq_desc_get_chip(desc), desc);
}

static int imx_intmux_probe(struct platform_device *pdev)
{
        struct device_node *np = pdev->dev.of_node;
        struct irq_domain *domain;
        struct intmux_data *data;
        int channum;
        int i, ret;

        channum = platform_irq_count(pdev);
        if (channum == -EPROBE_DEFER) {
                return -EPROBE_DEFER;
        } else if (channum > CHAN_MAX_NUM) {
                dev_err(&pdev->dev, "supports up to %d multiplex channels\n",
                        CHAN_MAX_NUM);
                return -EINVAL;
        }

        data = devm_kzalloc(&pdev->dev, struct_size(data, irqchip_data, channum), GFP_KERNEL);
        if (!data)
                return -ENOMEM;

        data->regs = devm_platform_ioremap_resource(pdev, 0);
        if (IS_ERR(data->regs)) {
                dev_err(&pdev->dev, "failed to initialize reg\n");
                return PTR_ERR(data->regs);
        }

        data->ipg_clk = devm_clk_get(&pdev->dev, "ipg");
        if (IS_ERR(data->ipg_clk))
                return dev_err_probe(&pdev->dev, PTR_ERR(data->ipg_clk),
                                     "failed to get ipg clk\n");

        data->channum = channum;
        raw_spin_lock_init(&data->lock);

        pm_runtime_get_noresume(&pdev->dev);
        pm_runtime_set_active(&pdev->dev);
        pm_runtime_enable(&pdev->dev);

        ret = clk_prepare_enable(data->ipg_clk);
        if (ret) {
                dev_err(&pdev->dev, "failed to enable ipg clk: %d\n", ret);
                return ret;
        }

        for (i = 0; i < channum; i++) {
                data->irqchip_data[i].chanidx = i;

                data->irqchip_data[i].irq = irq_of_parse_and_map(np, i);
                if (data->irqchip_data[i].irq <= 0) {
                        ret = -EINVAL;
                        dev_err(&pdev->dev, "failed to get irq\n");
                        goto out;
                }

                domain = irq_domain_create_linear(of_fwnode_handle(np), 32, &imx_intmux_domain_ops,
                                               &data->irqchip_data[i]);
                if (!domain) {
                        ret = -ENOMEM;
                        dev_err(&pdev->dev, "failed to create IRQ domain\n");
                        goto out;
                }
                data->irqchip_data[i].domain = domain;
                irq_domain_set_pm_device(domain, &pdev->dev);

                /* disable all interrupt sources of this channel firstly */
                writel_relaxed(0, data->regs + CHANIER(i));

                irq_set_chained_handler_and_data(data->irqchip_data[i].irq,
                                                 imx_intmux_irq_handler,
                                                 &data->irqchip_data[i]);
        }

        platform_set_drvdata(pdev, data);

        /*
         * Let pm_runtime_put() disable clock.
         * If CONFIG_PM is not enabled, the clock will stay powered.
         */
        pm_runtime_put(&pdev->dev);

        return 0;
out:
        clk_disable_unprepare(data->ipg_clk);
        return ret;
}

static void imx_intmux_remove(struct platform_device *pdev)
{
        struct intmux_data *data = platform_get_drvdata(pdev);
        int i;

        for (i = 0; i < data->channum; i++) {
                /* disable all interrupt sources of this channel */
                writel_relaxed(0, data->regs + CHANIER(i));

                irq_set_chained_handler_and_data(data->irqchip_data[i].irq,
                                                 NULL, NULL);

                irq_domain_remove(data->irqchip_data[i].domain);
        }

        pm_runtime_disable(&pdev->dev);
}

#ifdef CONFIG_PM
static int imx_intmux_runtime_suspend(struct device *dev)
{
        struct intmux_data *data = dev_get_drvdata(dev);
        struct intmux_irqchip_data *irqchip_data;
        int i;

        for (i = 0; i < data->channum; i++) {
                irqchip_data = &data->irqchip_data[i];
                irqchip_data->saved_reg = readl_relaxed(data->regs + CHANIER(i));
        }

        clk_disable_unprepare(data->ipg_clk);

        return 0;
}

static int imx_intmux_runtime_resume(struct device *dev)
{
        struct intmux_data *data = dev_get_drvdata(dev);
        struct intmux_irqchip_data *irqchip_data;
        int ret, i;

        ret = clk_prepare_enable(data->ipg_clk);
        if (ret) {
                dev_err(dev, "failed to enable ipg clk: %d\n", ret);
                return ret;
        }

        for (i = 0; i < data->channum; i++) {
                irqchip_data = &data->irqchip_data[i];
                writel_relaxed(irqchip_data->saved_reg, data->regs + CHANIER(i));
        }

        return 0;
}
#endif

static const struct dev_pm_ops imx_intmux_pm_ops = {
        SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
                                      pm_runtime_force_resume)
        SET_RUNTIME_PM_OPS(imx_intmux_runtime_suspend,
                           imx_intmux_runtime_resume, NULL)
};

static const struct of_device_id imx_intmux_id[] = {
        { .compatible = "fsl,imx-intmux", },
        { /* sentinel */ },
};

static struct platform_driver imx_intmux_driver = {
        .driver = {
                .name           = "imx-intmux",
                .of_match_table = imx_intmux_id,
                .pm             = &imx_intmux_pm_ops,
        },
        .probe          = imx_intmux_probe,
        .remove         = imx_intmux_remove,
};
builtin_platform_driver(imx_intmux_driver);