// SPDX-License-Identifier: GPL-2.0
/*
 * dwc3-keystone.c - Keystone Specific Glue layer
 *
 * Copyright (C) 2010-2013 Texas Instruments Incorporated - https://www.ti.com
 *
 * Author: WingMan Kwok <w-kwok2@ti.com>
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/dma-mapping.h>
#include <linux/io.h>
#include <linux/of.h>
#include <linux/of_platform.h>
#include <linux/phy/phy.h>
#include <linux/pm_runtime.h>

/* USBSS register offsets */
#define USBSS_REVISION          0x0000
#define USBSS_SYSCONFIG         0x0010
#define USBSS_IRQ_EOI           0x0018
#define USBSS_IRQSTATUS_RAW_0   0x0020
#define USBSS_IRQSTATUS_0       0x0024
#define USBSS_IRQENABLE_SET_0   0x0028
#define USBSS_IRQENABLE_CLR_0   0x002c

/* IRQ register bits */
#define USBSS_IRQ_EOI_LINE(n)   BIT(n)
#define USBSS_IRQ_EVENT_ST      BIT(0)
#define USBSS_IRQ_COREIRQ_EN    BIT(0)
#define USBSS_IRQ_COREIRQ_CLR   BIT(0)

struct dwc3_keystone {
        struct device                   *dev;
        void __iomem                    *usbss;
        struct phy                      *usb3_phy;
};

static inline u32 kdwc3_readl(void __iomem *base, u32 offset)
{
        return readl(base + offset);
}

static inline void kdwc3_writel(void __iomem *base, u32 offset, u32 value)
{
        writel(value, base + offset);
}

static void kdwc3_enable_irqs(struct dwc3_keystone *kdwc)
{
        u32 val;

        val = kdwc3_readl(kdwc->usbss, USBSS_IRQENABLE_SET_0);
        val |= USBSS_IRQ_COREIRQ_EN;
        kdwc3_writel(kdwc->usbss, USBSS_IRQENABLE_SET_0, val);
}

static void kdwc3_disable_irqs(struct dwc3_keystone *kdwc)
{
        u32 val;

        val = kdwc3_readl(kdwc->usbss, USBSS_IRQENABLE_SET_0);
        val &= ~USBSS_IRQ_COREIRQ_EN;
        kdwc3_writel(kdwc->usbss, USBSS_IRQENABLE_SET_0, val);
}

static irqreturn_t dwc3_keystone_interrupt(int irq, void *_kdwc)
{
        struct dwc3_keystone    *kdwc = _kdwc;

        kdwc3_writel(kdwc->usbss, USBSS_IRQENABLE_CLR_0, USBSS_IRQ_COREIRQ_CLR);
        kdwc3_writel(kdwc->usbss, USBSS_IRQSTATUS_0, USBSS_IRQ_EVENT_ST);
        kdwc3_writel(kdwc->usbss, USBSS_IRQENABLE_SET_0, USBSS_IRQ_COREIRQ_EN);
        kdwc3_writel(kdwc->usbss, USBSS_IRQ_EOI, USBSS_IRQ_EOI_LINE(0));

        return IRQ_HANDLED;
}

static int kdwc3_probe(struct platform_device *pdev)
{
        struct device           *dev = &pdev->dev;
        struct device_node      *node = pdev->dev.of_node;
        struct dwc3_keystone    *kdwc;
        int                     error, irq;

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

        platform_set_drvdata(pdev, kdwc);

        kdwc->dev = dev;

        kdwc->usbss = devm_platform_ioremap_resource(pdev, 0);
        if (IS_ERR(kdwc->usbss))
                return PTR_ERR(kdwc->usbss);

        /* PSC dependency on AM65 needs SERDES0 to be powered before USB0 */
        kdwc->usb3_phy = devm_phy_optional_get(dev, "usb3-phy");
        if (IS_ERR(kdwc->usb3_phy))
                return dev_err_probe(dev, PTR_ERR(kdwc->usb3_phy), "couldn't get usb3 phy\n");

        phy_pm_runtime_get_sync(kdwc->usb3_phy);

        error = phy_reset(kdwc->usb3_phy);
        if (error < 0) {
                dev_err(dev, "usb3 phy reset failed: %d\n", error);
                return error;
        }

        error = phy_init(kdwc->usb3_phy);
        if (error < 0) {
                dev_err(dev, "usb3 phy init failed: %d\n", error);
                return error;
        }

        error = phy_power_on(kdwc->usb3_phy);
        if (error < 0) {
                dev_err(dev, "usb3 phy power on failed: %d\n", error);
                phy_exit(kdwc->usb3_phy);
                return error;
        }

        pm_runtime_enable(kdwc->dev);
        error = pm_runtime_get_sync(kdwc->dev);
        if (error < 0) {
                dev_err(kdwc->dev, "pm_runtime_get_sync failed, error %d\n",
                        error);
                goto err_irq;
        }

        /* IRQ processing not required currently for AM65 */
        if (of_device_is_compatible(node, "ti,am654-dwc3"))
                goto skip_irq;

        irq = platform_get_irq(pdev, 0);
        if (irq < 0) {
                error = irq;
                goto err_irq;
        }

        error = devm_request_irq(dev, irq, dwc3_keystone_interrupt, IRQF_SHARED,
                        dev_name(dev), kdwc);
        if (error) {
                dev_err(dev, "failed to request IRQ #%d --> %d\n",
                                irq, error);
                goto err_irq;
        }

        kdwc3_enable_irqs(kdwc);

skip_irq:
        error = of_platform_populate(node, NULL, NULL, dev);
        if (error) {
                dev_err(&pdev->dev, "failed to create dwc3 core\n");
                goto err_core;
        }

        return 0;

err_core:
        kdwc3_disable_irqs(kdwc);
err_irq:
        pm_runtime_put_sync(kdwc->dev);
        pm_runtime_disable(kdwc->dev);
        phy_power_off(kdwc->usb3_phy);
        phy_exit(kdwc->usb3_phy);
        phy_pm_runtime_put_sync(kdwc->usb3_phy);

        return error;
}

static int kdwc3_remove_core(struct device *dev, void *c)
{
        struct platform_device *pdev = to_platform_device(dev);

        platform_device_unregister(pdev);

        return 0;
}

static void kdwc3_remove(struct platform_device *pdev)
{
        struct dwc3_keystone *kdwc = platform_get_drvdata(pdev);
        struct device_node *node = pdev->dev.of_node;

        if (!of_device_is_compatible(node, "ti,am654-dwc3"))
                kdwc3_disable_irqs(kdwc);

        device_for_each_child(&pdev->dev, NULL, kdwc3_remove_core);
        pm_runtime_put_sync(kdwc->dev);
        pm_runtime_disable(kdwc->dev);

        phy_power_off(kdwc->usb3_phy);
        phy_exit(kdwc->usb3_phy);
        phy_pm_runtime_put_sync(kdwc->usb3_phy);
}

static const struct of_device_id kdwc3_of_match[] = {
        { .compatible = "ti,keystone-dwc3", },
        { .compatible = "ti,am654-dwc3" },
        {},
};
MODULE_DEVICE_TABLE(of, kdwc3_of_match);

static struct platform_driver kdwc3_driver = {
        .probe          = kdwc3_probe,
        .remove         = kdwc3_remove,
        .driver         = {
                .name   = "keystone-dwc3",
                .of_match_table = kdwc3_of_match,
        },
};

module_platform_driver(kdwc3_driver);

MODULE_ALIAS("platform:keystone-dwc3");
MODULE_AUTHOR("WingMan Kwok <w-kwok2@ti.com>");
MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("DesignWare USB3 KEYSTONE Glue Layer");