// SPDX-License-Identifier: GPL-2.0
/*
 * cdns3-ti.c - TI specific Glue layer for Cadence USB Controller
 *
 * Copyright (C) 2019 Texas Instruments Incorporated - https://www.ti.com
 */

#include <linux/bits.h>
#include <linux/clk.h>
#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_platform.h>
#include <linux/pm_runtime.h>
#include <linux/property.h>
#include "core.h"

/* USB Wrapper register offsets */
#define USBSS_PID               0x0
#define USBSS_W1                0x4
#define USBSS_STATIC_CONFIG     0x8
#define USBSS_PHY_TEST          0xc
#define USBSS_DEBUG_CTRL        0x10
#define USBSS_DEBUG_INFO        0x14
#define USBSS_DEBUG_LINK_STATE  0x18
#define USBSS_DEVICE_CTRL       0x1c

/* Wrapper 1 register bits */
#define USBSS_W1_PWRUP_RST              BIT(0)
#define USBSS_W1_OVERCURRENT_SEL        BIT(8)
#define USBSS_W1_MODESTRAP_SEL          BIT(9)
#define USBSS_W1_OVERCURRENT            BIT(16)
#define USBSS_W1_MODESTRAP_MASK         GENMASK(18, 17)
#define USBSS_W1_MODESTRAP_SHIFT        17
#define USBSS_W1_USB2_ONLY              BIT(19)

/* Static config register bits */
#define USBSS1_STATIC_PLL_REF_SEL_MASK  GENMASK(8, 5)
#define USBSS1_STATIC_PLL_REF_SEL_SHIFT 5
#define USBSS1_STATIC_LOOPBACK_MODE_MASK        GENMASK(4, 3)
#define USBSS1_STATIC_LOOPBACK_MODE_SHIFT       3
#define USBSS1_STATIC_VBUS_SEL_MASK     GENMASK(2, 1)
#define USBSS1_STATIC_VBUS_SEL_SHIFT    1
#define USBSS1_STATIC_LANE_REVERSE      BIT(0)

/* Modestrap modes */
enum modestrap_mode { USBSS_MODESTRAP_MODE_NONE,
                      USBSS_MODESTRAP_MODE_HOST,
                      USBSS_MODESTRAP_MODE_PERIPHERAL};

struct cdns_ti {
        struct device *dev;
        void __iomem *usbss;
        unsigned usb2_only:1;
        unsigned vbus_divider:1;
        struct clk *usb2_refclk;
        struct clk *lpm_clk;
        int usb2_refclk_rate_code;
};

static const int cdns_ti_rate_table[] = {       /* in KHZ */
        9600,
        10000,
        12000,
        19200,
        20000,
        24000,
        25000,
        26000,
        38400,
        40000,
        58000,
        50000,
        52000,
};

static inline u32 cdns_ti_readl(struct cdns_ti *data, u32 offset)
{
        return readl(data->usbss + offset);
}

static inline void cdns_ti_writel(struct cdns_ti *data, u32 offset, u32 value)
{
        writel(value, data->usbss + offset);
}

static struct cdns3_platform_data cdns_ti_pdata = {
        .quirks = CDNS3_DRD_SUSPEND_RESIDENCY_ENABLE,   /* Errata i2409 */
};

static const struct of_dev_auxdata cdns_ti_auxdata[] = {
        {
                .compatible = "cdns,usb3",
                .platform_data = &cdns_ti_pdata,
        },
        {},
};

static void cdns_ti_reset_and_init_hw(struct cdns_ti *data)
{
        u32 reg;

        /* assert RESET */
        reg = cdns_ti_readl(data, USBSS_W1);
        reg &= ~USBSS_W1_PWRUP_RST;
        cdns_ti_writel(data, USBSS_W1, reg);

        /* set static config */
        reg = cdns_ti_readl(data, USBSS_STATIC_CONFIG);
        reg &= ~USBSS1_STATIC_PLL_REF_SEL_MASK;
        reg |= data->usb2_refclk_rate_code << USBSS1_STATIC_PLL_REF_SEL_SHIFT;

        reg &= ~USBSS1_STATIC_VBUS_SEL_MASK;
        if (data->vbus_divider)
                reg |= 1 << USBSS1_STATIC_VBUS_SEL_SHIFT;

        cdns_ti_writel(data, USBSS_STATIC_CONFIG, reg);
        reg = cdns_ti_readl(data, USBSS_STATIC_CONFIG);

        /* set USB2_ONLY mode if requested */
        reg = cdns_ti_readl(data, USBSS_W1);
        if (data->usb2_only)
                reg |= USBSS_W1_USB2_ONLY;

        /* set default modestrap */
        reg |= USBSS_W1_MODESTRAP_SEL;
        reg &= ~USBSS_W1_MODESTRAP_MASK;
        reg |= USBSS_MODESTRAP_MODE_NONE << USBSS_W1_MODESTRAP_SHIFT;
        cdns_ti_writel(data, USBSS_W1, reg);

        /* de-assert RESET */
        reg |= USBSS_W1_PWRUP_RST;
        cdns_ti_writel(data, USBSS_W1, reg);
}

static int cdns_ti_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct device_node *node = pdev->dev.of_node;
        struct cdns_ti *data;
        unsigned long rate;
        int error, i;

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

        platform_set_drvdata(pdev, data);

        data->dev = dev;

        data->usbss = devm_platform_ioremap_resource(pdev, 0);
        if (IS_ERR(data->usbss)) {
                dev_err(dev, "can't map IOMEM resource\n");
                return PTR_ERR(data->usbss);
        }

        data->usb2_refclk = devm_clk_get(dev, "ref");
        if (IS_ERR(data->usb2_refclk)) {
                dev_err(dev, "can't get usb2_refclk\n");
                return PTR_ERR(data->usb2_refclk);
        }

        data->lpm_clk = devm_clk_get(dev, "lpm");
        if (IS_ERR(data->lpm_clk)) {
                dev_err(dev, "can't get lpm_clk\n");
                return PTR_ERR(data->lpm_clk);
        }

        rate = clk_get_rate(data->usb2_refclk);
        rate /= 1000;   /* To KHz */
        for (i = 0; i < ARRAY_SIZE(cdns_ti_rate_table); i++) {
                if (cdns_ti_rate_table[i] == rate)
                        break;
        }

        if (i == ARRAY_SIZE(cdns_ti_rate_table)) {
                dev_err(dev, "unsupported usb2_refclk rate: %lu KHz\n", rate);
                return -EINVAL;
        }

        data->usb2_refclk_rate_code = i;
        data->vbus_divider = device_property_read_bool(dev, "ti,vbus-divider");
        data->usb2_only = device_property_read_bool(dev, "ti,usb2-only");

        /*
         * The call below to pm_runtime_get_sync() MIGHT reset hardware, if it
         * detects it as uninitialised. We want to enforce a reset at probe,
         * and so do it manually here. This means the first runtime_resume()
         * will be a no-op.
         */
        cdns_ti_reset_and_init_hw(data);

        pm_runtime_enable(dev);
        error = pm_runtime_get_sync(dev);
        if (error < 0) {
                dev_err(dev, "pm_runtime_get_sync failed: %d\n", error);
                goto err;
        }

        error = of_platform_populate(node, NULL, cdns_ti_auxdata, dev);
        if (error) {
                dev_err(dev, "failed to create children: %d\n", error);
                goto err;
        }

        return 0;

err:
        pm_runtime_put_sync(data->dev);
        pm_runtime_disable(data->dev);

        return error;
}

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

        platform_device_unregister(pdev);

        return 0;
}

static void cdns_ti_remove(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;

        device_for_each_child(dev, NULL, cdns_ti_remove_core);
        pm_runtime_put_sync(dev);
        pm_runtime_disable(dev);

        platform_set_drvdata(pdev, NULL);
}

static int cdns_ti_runtime_resume(struct device *dev)
{
        const u32 mask = USBSS_W1_PWRUP_RST | USBSS_W1_MODESTRAP_SEL;
        struct cdns_ti *data = dev_get_drvdata(dev);
        u32 w1;

        w1 = cdns_ti_readl(data, USBSS_W1);
        if ((w1 & mask) != mask)
                cdns_ti_reset_and_init_hw(data);

        return 0;
}

static const struct dev_pm_ops cdns_ti_pm_ops = {
        RUNTIME_PM_OPS(NULL, cdns_ti_runtime_resume, NULL)
        SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend, pm_runtime_force_resume)
};

static const struct of_device_id cdns_ti_of_match[] = {
        { .compatible = "ti,j721e-usb", },
        { .compatible = "ti,am64-usb", },
        {},
};
MODULE_DEVICE_TABLE(of, cdns_ti_of_match);

static struct platform_driver cdns_ti_driver = {
        .probe          = cdns_ti_probe,
        .remove         = cdns_ti_remove,
        .driver         = {
                .name   = "cdns3-ti",
                .of_match_table = cdns_ti_of_match,
                .pm     = pm_ptr(&cdns_ti_pm_ops),
        },
};

module_platform_driver(cdns_ti_driver);

MODULE_ALIAS("platform:cdns3-ti");
MODULE_AUTHOR("Roger Quadros <rogerq@ti.com>");
MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("Cadence USB3 TI Glue Layer");