root/drivers/usb/dwc3/dwc3-rtk.c
// SPDX-License-Identifier: GPL-2.0
/*
 * dwc3-rtk.c - Realtek DWC3 Specific Glue layer
 *
 * Copyright (C) 2023 Realtek Semiconductor Corporation
 *
 */

#include <linux/cleanup.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/platform_device.h>
#include <linux/of.h>
#include <linux/of_platform.h>
#include <linux/suspend.h>
#include <linux/sys_soc.h>
#include <linux/usb/otg.h>
#include <linux/usb/of.h>
#include <linux/usb/role.h>

#include "core.h"

#define WRAP_CTR_REG  0x0
#define DISABLE_MULTI_REQ BIT(1)
#define DESC_R2W_MULTI_DISABLE BIT(9)
#define FORCE_PIPE3_PHY_STATUS_TO_0 BIT(13)

#define WRAP_USB2_PHY_UTMI_REG 0x8
#define TXHSVM_EN BIT(3)

#define WRAP_PHY_PIPE_REG 0xC
#define RESET_DISABLE_PIPE3_P0 BIT(0)
#define CLOCK_ENABLE_FOR_PIPE3_PCLK BIT(1)

#define WRAP_USB_HMAC_CTR0_REG 0x60
#define U3PORT_DIS BIT(8)

#define WRAP_USB2_PHY_REG  0x70
#define USB2_PHY_EN_PHY_PLL_PORT0 BIT(12)
#define USB2_PHY_EN_PHY_PLL_PORT1 BIT(13)
#define USB2_PHY_SWITCH_MASK 0x707
#define USB2_PHY_SWITCH_DEVICE 0x0
#define USB2_PHY_SWITCH_HOST 0x606

#define WRAP_APHY_REG 0x128
#define USB3_MBIAS_ENABLE BIT(1)

/* pm control */
#define WRAP_USB_DBUS_PWR_CTRL_REG 0x160
#define USB_DBUS_PWR_CTRL_REG 0x0
#define DBUS_PWR_CTRL_EN BIT(0)

struct dwc3_rtk {
        struct device *dev;
        void __iomem *regs;
        size_t regs_size;
        void __iomem *pm_base;

        struct dwc3 *dwc;

        enum usb_role cur_role;
        struct usb_role_switch *role_switch;
};

static void switch_usb2_role(struct dwc3_rtk *rtk, enum usb_role role)
{
        void __iomem *reg;
        int val;

        reg = rtk->regs + WRAP_USB2_PHY_REG;
        val = ~USB2_PHY_SWITCH_MASK & readl(reg);

        switch (role) {
        case USB_ROLE_DEVICE:
                writel(USB2_PHY_SWITCH_DEVICE | val, reg);
                break;
        case USB_ROLE_HOST:
                writel(USB2_PHY_SWITCH_HOST | val, reg);
                break;
        default:
                dev_dbg(rtk->dev, "%s: role=%d\n", __func__, role);
                break;
        }
}

static void switch_dwc3_role(struct dwc3_rtk *rtk, enum usb_role role)
{
        if (!rtk->dwc->role_sw)
                return;

        usb_role_switch_set_role(rtk->dwc->role_sw, role);
}

static enum usb_role dwc3_rtk_get_role(struct dwc3_rtk *rtk)
{
        enum usb_role role;

        role = rtk->cur_role;

        if (rtk->dwc && rtk->dwc->role_sw)
                role = usb_role_switch_get_role(rtk->dwc->role_sw);
        else
                dev_dbg(rtk->dev, "%s not usb_role_switch role=%d\n", __func__, role);

        return role;
}

static void dwc3_rtk_set_role(struct dwc3_rtk *rtk, enum usb_role role)
{
        rtk->cur_role = role;

        switch_dwc3_role(rtk, role);
        mdelay(10);
        switch_usb2_role(rtk, role);
}

#if IS_ENABLED(CONFIG_USB_ROLE_SWITCH)
static int dwc3_usb_role_switch_set(struct usb_role_switch *sw, enum usb_role role)
{
        struct dwc3_rtk *rtk = usb_role_switch_get_drvdata(sw);

        dwc3_rtk_set_role(rtk, role);

        return 0;
}

static enum usb_role dwc3_usb_role_switch_get(struct usb_role_switch *sw)
{
        struct dwc3_rtk *rtk = usb_role_switch_get_drvdata(sw);

        return dwc3_rtk_get_role(rtk);
}

static int dwc3_rtk_setup_role_switch(struct dwc3_rtk *rtk)
{
        struct usb_role_switch_desc dwc3_role_switch = {NULL};

        dwc3_role_switch.name = dev_name(rtk->dev);
        dwc3_role_switch.driver_data = rtk;
        dwc3_role_switch.allow_userspace_control = true;
        dwc3_role_switch.fwnode = dev_fwnode(rtk->dev);
        dwc3_role_switch.set = dwc3_usb_role_switch_set;
        dwc3_role_switch.get = dwc3_usb_role_switch_get;
        rtk->role_switch = usb_role_switch_register(rtk->dev, &dwc3_role_switch);
        if (IS_ERR(rtk->role_switch))
                return PTR_ERR(rtk->role_switch);

        return 0;
}

static int dwc3_rtk_remove_role_switch(struct dwc3_rtk *rtk)
{
        if (rtk->role_switch)
                usb_role_switch_unregister(rtk->role_switch);

        rtk->role_switch = NULL;

        return 0;
}
#else
#define dwc3_rtk_setup_role_switch(x) 0
#define dwc3_rtk_remove_role_switch(x) 0
#endif

static const char *const speed_names[] = {
        [USB_SPEED_UNKNOWN] = "UNKNOWN",
        [USB_SPEED_LOW] = "low-speed",
        [USB_SPEED_FULL] = "full-speed",
        [USB_SPEED_HIGH] = "high-speed",
        [USB_SPEED_WIRELESS] = "wireless",
        [USB_SPEED_SUPER] = "super-speed",
        [USB_SPEED_SUPER_PLUS] = "super-speed-plus",
};

static enum usb_device_speed __get_dwc3_maximum_speed(struct device_node *np)
{
        const char *maximum_speed;
        int ret;

        struct device_node *dwc3_np __free(device_node) = of_get_compatible_child(np,
                                                                                  "snps,dwc3");
        if (!dwc3_np)
                return USB_SPEED_UNKNOWN;

        ret = of_property_read_string(dwc3_np, "maximum-speed", &maximum_speed);
        if (ret < 0)
                return USB_SPEED_UNKNOWN;

        ret = match_string(speed_names, ARRAY_SIZE(speed_names), maximum_speed);

        return (ret < 0) ? USB_SPEED_UNKNOWN : ret;
}

static int dwc3_rtk_init(struct dwc3_rtk *rtk)
{
        struct device *dev = rtk->dev;
        void __iomem *reg;
        int val;
        enum usb_device_speed maximum_speed;
        const struct soc_device_attribute rtk_soc_kylin_a00[] = {
                { .family = "Realtek Kylin", .revision = "A00", },
                { /* empty */ } };
        const struct soc_device_attribute rtk_soc_hercules[] = {
                { .family = "Realtek Hercules", }, { /* empty */ } };
        const struct soc_device_attribute rtk_soc_thor[] = {
                { .family = "Realtek Thor", }, { /* empty */ } };

        if (soc_device_match(rtk_soc_kylin_a00)) {
                reg = rtk->regs + WRAP_CTR_REG;
                val = readl(reg);
                writel(DISABLE_MULTI_REQ | val, reg);
                dev_info(dev, "[bug fixed] 1295/1296 A00: add workaround to disable multiple request for D-Bus");
        }

        if (soc_device_match(rtk_soc_hercules)) {
                reg = rtk->regs + WRAP_USB2_PHY_REG;
                val = readl(reg);
                writel(USB2_PHY_EN_PHY_PLL_PORT1 | val, reg);
                dev_info(dev, "[bug fixed] 1395 add workaround to disable usb2 port 2 suspend!");
        }

        reg = rtk->regs + WRAP_USB2_PHY_UTMI_REG;
        val = readl(reg);
        writel(TXHSVM_EN | val, reg);

        maximum_speed = __get_dwc3_maximum_speed(dev->of_node);
        if (maximum_speed != USB_SPEED_UNKNOWN && maximum_speed <= USB_SPEED_HIGH) {
                if (soc_device_match(rtk_soc_thor)) {
                        reg = rtk->regs + WRAP_USB_HMAC_CTR0_REG;
                        val = readl(reg);
                        writel(U3PORT_DIS | val, reg);
                } else {
                        reg = rtk->regs + WRAP_CTR_REG;
                        val = readl(reg);
                        writel(FORCE_PIPE3_PHY_STATUS_TO_0 | val, reg);

                        reg = rtk->regs + WRAP_PHY_PIPE_REG;
                        val = ~CLOCK_ENABLE_FOR_PIPE3_PCLK & readl(reg);
                        writel(RESET_DISABLE_PIPE3_P0 | val, reg);

                        reg =  rtk->regs + WRAP_USB_HMAC_CTR0_REG;
                        val = readl(reg);
                        writel(U3PORT_DIS | val, reg);

                        reg = rtk->regs + WRAP_APHY_REG;
                        val = readl(reg);
                        writel(~USB3_MBIAS_ENABLE & val, reg);

                        dev_dbg(rtk->dev, "%s: disable usb 3.0 phy\n", __func__);
                }
        }

        reg = rtk->regs + WRAP_CTR_REG;
        val = readl(reg);
        writel(DESC_R2W_MULTI_DISABLE | val, reg);

        /* Set phy Dp/Dm initial state to host mode to avoid the Dp glitch */
        reg = rtk->regs + WRAP_USB2_PHY_REG;
        val = ~USB2_PHY_SWITCH_MASK & readl(reg);
        writel(USB2_PHY_SWITCH_HOST | val, reg);

        if (rtk->pm_base) {
                reg = rtk->pm_base + USB_DBUS_PWR_CTRL_REG;
                val = DBUS_PWR_CTRL_EN | readl(reg);
                writel(val, reg);
        }

        return 0;
}

static int dwc3_rtk_probe_dwc3_core(struct dwc3_rtk *rtk)
{
        struct device *dev = rtk->dev;
        struct device_node *node = dev->of_node;
        struct platform_device *dwc3_pdev;
        struct device *dwc3_dev;
        enum usb_dr_mode dr_mode;
        int ret = 0;

        ret = dwc3_rtk_init(rtk);
        if (ret)
                return -EINVAL;

        ret = of_platform_populate(node, NULL, NULL, dev);
        if (ret) {
                dev_err(dev, "failed to add dwc3 core\n");
                return ret;
        }

        struct device_node *dwc3_node __free(device_node) = of_get_compatible_child(node,
                                                                                    "snps,dwc3");
        if (!dwc3_node) {
                dev_err(dev, "failed to find dwc3 core node\n");
                ret = -ENODEV;
                goto depopulate;
        }

        dwc3_pdev = of_find_device_by_node(dwc3_node);
        if (!dwc3_pdev) {
                dev_err(dev, "failed to find dwc3 core platform_device\n");
                ret = -ENODEV;
                goto depopulate;
        }

        dwc3_dev = &dwc3_pdev->dev;
        rtk->dwc = platform_get_drvdata(dwc3_pdev);
        if (!rtk->dwc) {
                dev_err(dev, "failed to find dwc3 core\n");
                ret = -ENODEV;
                goto err_pdev_put;
        }

        dr_mode = usb_get_dr_mode(dwc3_dev);
        if (dr_mode != rtk->dwc->dr_mode) {
                dev_info(dev, "dts set dr_mode=%d, but dwc3 set dr_mode=%d\n",
                         dr_mode, rtk->dwc->dr_mode);
                dr_mode = rtk->dwc->dr_mode;
        }

        switch (dr_mode) {
        case USB_DR_MODE_PERIPHERAL:
                rtk->cur_role = USB_ROLE_DEVICE;
                break;
        case USB_DR_MODE_HOST:
                rtk->cur_role = USB_ROLE_HOST;
                break;
        default:
                dev_dbg(rtk->dev, "%s: dr_mode=%d\n", __func__, dr_mode);
                break;
        }

        if (device_property_read_bool(dwc3_dev, "usb-role-switch")) {
                ret = dwc3_rtk_setup_role_switch(rtk);
                if (ret) {
                        dev_err(dev, "dwc3_rtk_setup_role_switch fail=%d\n", ret);
                        goto err_pdev_put;
                }
                rtk->cur_role = dwc3_rtk_get_role(rtk);
        }

        switch_usb2_role(rtk, rtk->cur_role);

        platform_device_put(dwc3_pdev);

        return 0;

err_pdev_put:
        platform_device_put(dwc3_pdev);
depopulate:
        of_platform_depopulate(dev);

        return ret;
}

static int dwc3_rtk_probe(struct platform_device *pdev)
{
        struct dwc3_rtk *rtk;
        struct device *dev = &pdev->dev;
        struct resource *res;
        void __iomem *regs;

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

        platform_set_drvdata(pdev, rtk);

        rtk->dev = dev;

        regs = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
        if (IS_ERR(regs))
                return PTR_ERR(regs);

        rtk->regs = regs;
        rtk->regs_size = resource_size(res);

        res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
        if (res) {
                rtk->pm_base = devm_ioremap_resource(dev, res);
                if (IS_ERR(rtk->pm_base))
                        return PTR_ERR(rtk->pm_base);
        }

        return dwc3_rtk_probe_dwc3_core(rtk);
}

static void dwc3_rtk_remove(struct platform_device *pdev)
{
        struct dwc3_rtk *rtk = platform_get_drvdata(pdev);

        rtk->dwc = NULL;

        dwc3_rtk_remove_role_switch(rtk);

        of_platform_depopulate(rtk->dev);
}

static void dwc3_rtk_shutdown(struct platform_device *pdev)
{
        struct dwc3_rtk *rtk = platform_get_drvdata(pdev);

        of_platform_depopulate(rtk->dev);
}

static const struct of_device_id rtk_dwc3_match[] = {
        { .compatible = "realtek,rtd-dwc3" },
        {},
};
MODULE_DEVICE_TABLE(of, rtk_dwc3_match);

#ifdef CONFIG_PM_SLEEP
static int dwc3_rtk_suspend(struct device *dev)
{
        return 0;
}

static int dwc3_rtk_resume(struct device *dev)
{
        struct dwc3_rtk *rtk = dev_get_drvdata(dev);

        dwc3_rtk_init(rtk);

        switch_usb2_role(rtk, rtk->cur_role);

        /* runtime set active to reflect active state. */
        pm_runtime_disable(dev);
        pm_runtime_set_active(dev);
        pm_runtime_enable(dev);

        return 0;
}

static const struct dev_pm_ops dwc3_rtk_dev_pm_ops = {
        SET_SYSTEM_SLEEP_PM_OPS(dwc3_rtk_suspend, dwc3_rtk_resume)
};

#define DEV_PM_OPS      (&dwc3_rtk_dev_pm_ops)
#else
#define DEV_PM_OPS      NULL
#endif /* CONFIG_PM_SLEEP */

static struct platform_driver dwc3_rtk_driver = {
        .probe          = dwc3_rtk_probe,
        .remove         = dwc3_rtk_remove,
        .driver         = {
                .name   = "rtk-dwc3",
                .of_match_table = rtk_dwc3_match,
                .pm     = DEV_PM_OPS,
        },
        .shutdown       = dwc3_rtk_shutdown,
};

module_platform_driver(dwc3_rtk_driver);

MODULE_AUTHOR("Stanley Chang <stanley_chang@realtek.com>");
MODULE_DESCRIPTION("DesignWare USB3 Realtek Glue Layer");
MODULE_ALIAS("platform:rtk-dwc3");
MODULE_LICENSE("GPL");
MODULE_SOFTDEP("pre: phy_rtk_usb2 phy_rtk_usb3");