// SPDX-License-Identifier: GPL-2.0
/*
 * drd.c - DesignWare USB3 DRD Controller Dual-role support
 *
 * Copyright (C) 2017 Texas Instruments Incorporated - https://www.ti.com
 *
 * Authors: Roger Quadros <rogerq@ti.com>
 */

#include <linux/extcon.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
#include <linux/property.h>

#include "debug.h"
#include "core.h"
#include "gadget.h"

static void dwc3_otg_disable_events(struct dwc3 *dwc, u32 disable_mask)
{
        u32 reg = dwc3_readl(dwc, DWC3_OEVTEN);

        reg &= ~(disable_mask);
        dwc3_writel(dwc, DWC3_OEVTEN, reg);
}

static void dwc3_otg_enable_events(struct dwc3 *dwc, u32 enable_mask)
{
        u32 reg = dwc3_readl(dwc, DWC3_OEVTEN);

        reg |= (enable_mask);
        dwc3_writel(dwc, DWC3_OEVTEN, reg);
}

static void dwc3_otg_clear_events(struct dwc3 *dwc)
{
        u32 reg = dwc3_readl(dwc, DWC3_OEVT);

        dwc3_writel(dwc, DWC3_OEVTEN, reg);
}

#define DWC3_OTG_ALL_EVENTS     (DWC3_OEVTEN_XHCIRUNSTPSETEN | \
                DWC3_OEVTEN_DEVRUNSTPSETEN | DWC3_OEVTEN_HIBENTRYEN | \
                DWC3_OEVTEN_CONIDSTSCHNGEN | DWC3_OEVTEN_HRRCONFNOTIFEN | \
                DWC3_OEVTEN_HRRINITNOTIFEN | DWC3_OEVTEN_ADEVIDLEEN | \
                DWC3_OEVTEN_ADEVBHOSTENDEN | DWC3_OEVTEN_ADEVHOSTEN | \
                DWC3_OEVTEN_ADEVHNPCHNGEN | DWC3_OEVTEN_ADEVSRPDETEN | \
                DWC3_OEVTEN_ADEVSESSENDDETEN | DWC3_OEVTEN_BDEVBHOSTENDEN | \
                DWC3_OEVTEN_BDEVHNPCHNGEN | DWC3_OEVTEN_BDEVSESSVLDDETEN | \
                DWC3_OEVTEN_BDEVVBUSCHNGEN)

static irqreturn_t dwc3_otg_thread_irq(int irq, void *_dwc)
{
        struct dwc3 *dwc = _dwc;

        spin_lock(&dwc->lock);
        if (dwc->otg_restart_host) {
                dwc3_otg_host_init(dwc);
                dwc->otg_restart_host = false;
        }

        spin_unlock(&dwc->lock);

        dwc3_set_mode(dwc, DWC3_GCTL_PRTCAP_OTG);

        return IRQ_HANDLED;
}

static irqreturn_t dwc3_otg_irq(int irq, void *_dwc)
{
        u32 reg;
        struct dwc3 *dwc = _dwc;
        irqreturn_t ret = IRQ_NONE;

        reg = dwc3_readl(dwc, DWC3_OEVT);
        if (reg) {
                /* ignore non OTG events, we can't disable them in OEVTEN */
                if (!(reg & DWC3_OTG_ALL_EVENTS)) {
                        dwc3_writel(dwc, DWC3_OEVT, reg);
                        return IRQ_NONE;
                }

                if (dwc->current_otg_role == DWC3_OTG_ROLE_HOST &&
                    !(reg & DWC3_OEVT_DEVICEMODE))
                        dwc->otg_restart_host = true;
                dwc3_writel(dwc, DWC3_OEVT, reg);
                ret = IRQ_WAKE_THREAD;
        }

        return ret;
}

static void dwc3_otgregs_init(struct dwc3 *dwc)
{
        u32 reg;

        /*
         * Prevent host/device reset from resetting OTG core.
         * If we don't do this then xhci_reset (USBCMD.HCRST) will reset
         * the signal outputs sent to the PHY, the OTG FSM logic of the
         * core and also the resets to the VBUS filters inside the core.
         */
        reg = dwc3_readl(dwc, DWC3_OCFG);
        reg |= DWC3_OCFG_SFTRSTMASK;
        dwc3_writel(dwc, DWC3_OCFG, reg);

        /* Disable hibernation for simplicity */
        reg = dwc3_readl(dwc, DWC3_GCTL);
        reg &= ~DWC3_GCTL_GBLHIBERNATIONEN;
        dwc3_writel(dwc, DWC3_GCTL, reg);

        /*
         * Initialize OTG registers as per
         * Figure 11-4 OTG Driver Overall Programming Flow
         */
        /* OCFG.SRPCap = 0, OCFG.HNPCap = 0 */
        reg = dwc3_readl(dwc, DWC3_OCFG);
        reg &= ~(DWC3_OCFG_SRPCAP | DWC3_OCFG_HNPCAP);
        dwc3_writel(dwc, DWC3_OCFG, reg);
        /* OEVT = FFFF */
        dwc3_otg_clear_events(dwc);
        /* OEVTEN = 0 */
        dwc3_otg_disable_events(dwc, DWC3_OTG_ALL_EVENTS);
        /* OEVTEN.ConIDStsChngEn = 1. Instead we enable all events */
        dwc3_otg_enable_events(dwc, DWC3_OTG_ALL_EVENTS);
        /*
         * OCTL.PeriMode = 1, OCTL.DevSetHNPEn = 0, OCTL.HstSetHNPEn = 0,
         * OCTL.HNPReq = 0
         */
        reg = dwc3_readl(dwc, DWC3_OCTL);
        reg |= DWC3_OCTL_PERIMODE;
        reg &= ~(DWC3_OCTL_DEVSETHNPEN | DWC3_OCTL_HSTSETHNPEN |
                 DWC3_OCTL_HNPREQ);
        dwc3_writel(dwc, DWC3_OCTL, reg);
}

static int dwc3_otg_get_irq(struct dwc3 *dwc)
{
        struct platform_device *dwc3_pdev = to_platform_device(dwc->dev);
        int irq;

        irq = platform_get_irq_byname_optional(dwc3_pdev, "otg");
        if (irq > 0)
                goto out;

        if (irq == -EPROBE_DEFER)
                goto out;

        irq = platform_get_irq_byname_optional(dwc3_pdev, "dwc_usb3");
        if (irq > 0)
                goto out;

        if (irq == -EPROBE_DEFER)
                goto out;

        irq = platform_get_irq(dwc3_pdev, 0);
        if (irq > 0)
                goto out;

        if (!irq)
                irq = -EINVAL;

out:
        return irq;
}

void dwc3_otg_init(struct dwc3 *dwc)
{
        u32 reg;

        /*
         * As per Figure 11-4 OTG Driver Overall Programming Flow,
         * block "Initialize GCTL for OTG operation".
         */
        /* GCTL.PrtCapDir=2'b11 */
        dwc3_set_prtcap(dwc, DWC3_GCTL_PRTCAP_OTG, true);
        /* GUSB2PHYCFG0.SusPHY=0 */
        reg = dwc3_readl(dwc, DWC3_GUSB2PHYCFG(0));
        reg &= ~DWC3_GUSB2PHYCFG_SUSPHY;
        dwc3_writel(dwc, DWC3_GUSB2PHYCFG(0), reg);

        /* Initialize OTG registers */
        dwc3_otgregs_init(dwc);
}

void dwc3_otg_exit(struct dwc3 *dwc)
{
        /* disable all OTG IRQs */
        dwc3_otg_disable_events(dwc, DWC3_OTG_ALL_EVENTS);
        /* clear all events */
        dwc3_otg_clear_events(dwc);
}

/* should be called before Host controller driver is started */
void dwc3_otg_host_init(struct dwc3 *dwc)
{
        u32 reg;

        /* As per Figure 11-10 A-Device Flow Diagram */
        /* OCFG.HNPCap = 0, OCFG.SRPCap = 0. Already 0 */

        /*
         * OCTL.PeriMode=0, OCTL.TermSelDLPulse = 0,
         * OCTL.DevSetHNPEn = 0, OCTL.HstSetHNPEn = 0
         */
        reg = dwc3_readl(dwc, DWC3_OCTL);
        reg &= ~(DWC3_OCTL_PERIMODE | DWC3_OCTL_TERMSELIDPULSE |
                        DWC3_OCTL_DEVSETHNPEN | DWC3_OCTL_HSTSETHNPEN);
        dwc3_writel(dwc, DWC3_OCTL, reg);

        /*
         * OCFG.DisPrtPwrCutoff = 0/1
         */
        reg = dwc3_readl(dwc, DWC3_OCFG);
        reg &= ~DWC3_OCFG_DISPWRCUTTOFF;
        dwc3_writel(dwc, DWC3_OCFG, reg);

        /*
         * OCFG.SRPCap = 1, OCFG.HNPCap = GHWPARAMS6.HNP_CAP
         * We don't want SRP/HNP for simple dual-role so leave
         * these disabled.
         */

        /*
         * OEVTEN.OTGADevHostEvntEn = 1
         * OEVTEN.OTGADevSessEndDetEvntEn = 1
         * We don't want HNP/role-swap so leave these disabled.
         */

        /* GUSB2PHYCFG.ULPIAutoRes = 1/0, GUSB2PHYCFG.SusPHY = 1 */
        if (!dwc->dis_u2_susphy_quirk) {
                reg = dwc3_readl(dwc, DWC3_GUSB2PHYCFG(0));
                reg |= DWC3_GUSB2PHYCFG_SUSPHY;
                dwc3_writel(dwc, DWC3_GUSB2PHYCFG(0), reg);
        }

        /* Set Port Power to enable VBUS: OCTL.PrtPwrCtl = 1 */
        reg = dwc3_readl(dwc, DWC3_OCTL);
        reg |= DWC3_OCTL_PRTPWRCTL;
        dwc3_writel(dwc, DWC3_OCTL, reg);
}

/* should be called after Host controller driver is stopped */
static void dwc3_otg_host_exit(struct dwc3 *dwc)
{
        u32 reg;

        /*
         * Exit from A-device flow as per
         * Figure 11-4 OTG Driver Overall Programming Flow
         */

        /*
         * OEVTEN.OTGADevBHostEndEvntEn=0, OEVTEN.OTGADevHNPChngEvntEn=0
         * OEVTEN.OTGADevSessEndDetEvntEn=0,
         * OEVTEN.OTGADevHostEvntEn = 0
         * But we don't disable any OTG events
         */

        /* OCTL.HstSetHNPEn = 0, OCTL.PrtPwrCtl=0 */
        reg = dwc3_readl(dwc, DWC3_OCTL);
        reg &= ~(DWC3_OCTL_HSTSETHNPEN | DWC3_OCTL_PRTPWRCTL);
        dwc3_writel(dwc, DWC3_OCTL, reg);
}

/* should be called before the gadget controller driver is started */
static void dwc3_otg_device_init(struct dwc3 *dwc)
{
        u32 reg;

        /* As per Figure 11-20 B-Device Flow Diagram */

        /*
         * OCFG.HNPCap = GHWPARAMS6.HNP_CAP, OCFG.SRPCap = 1
         * but we keep them 0 for simple dual-role operation.
         */
        reg = dwc3_readl(dwc, DWC3_OCFG);
        /* OCFG.OTGSftRstMsk = 0/1 */
        reg |= DWC3_OCFG_SFTRSTMASK;
        dwc3_writel(dwc, DWC3_OCFG, reg);
        /*
         * OCTL.PeriMode = 1
         * OCTL.TermSelDLPulse = 0/1, OCTL.HNPReq = 0
         * OCTL.DevSetHNPEn = 0, OCTL.HstSetHNPEn = 0
         */
        reg = dwc3_readl(dwc, DWC3_OCTL);
        reg |= DWC3_OCTL_PERIMODE;
        reg &= ~(DWC3_OCTL_TERMSELIDPULSE | DWC3_OCTL_HNPREQ |
                        DWC3_OCTL_DEVSETHNPEN | DWC3_OCTL_HSTSETHNPEN);
        dwc3_writel(dwc, DWC3_OCTL, reg);
        /* OEVTEN.OTGBDevSesVldDetEvntEn = 1 */
        dwc3_otg_enable_events(dwc, DWC3_OEVTEN_BDEVSESSVLDDETEN);
        /* GUSB2PHYCFG.ULPIAutoRes = 0, GUSB2PHYCFG0.SusPHY = 1 */
        if (!dwc->dis_u2_susphy_quirk) {
                reg = dwc3_readl(dwc, DWC3_GUSB2PHYCFG(0));
                reg |= DWC3_GUSB2PHYCFG_SUSPHY;
                dwc3_writel(dwc, DWC3_GUSB2PHYCFG(0), reg);
        }
        /* GCTL.GblHibernationEn = 0. Already 0. */
}

/* should be called after the gadget controller driver is stopped */
static void dwc3_otg_device_exit(struct dwc3 *dwc)
{
        u32 reg;

        /*
         * Exit from B-device flow as per
         * Figure 11-4 OTG Driver Overall Programming Flow
         */

        /*
         * OEVTEN.OTGBDevHNPChngEvntEn = 0
         * OEVTEN.OTGBDevVBusChngEvntEn = 0
         * OEVTEN.OTGBDevBHostEndEvntEn = 0
         */
        dwc3_otg_disable_events(dwc, DWC3_OEVTEN_BDEVHNPCHNGEN |
                                DWC3_OEVTEN_BDEVVBUSCHNGEN |
                                DWC3_OEVTEN_BDEVBHOSTENDEN);

        /* OCTL.DevSetHNPEn = 0, OCTL.HNPReq = 0, OCTL.PeriMode=1 */
        reg = dwc3_readl(dwc, DWC3_OCTL);
        reg &= ~(DWC3_OCTL_DEVSETHNPEN | DWC3_OCTL_HNPREQ);
        reg |= DWC3_OCTL_PERIMODE;
        dwc3_writel(dwc, DWC3_OCTL, reg);
}

void dwc3_otg_update(struct dwc3 *dwc, bool ignore_idstatus)
{
        int ret;
        u32 reg;
        int id;
        unsigned long flags;
        int i;

        if (dwc->dr_mode != USB_DR_MODE_OTG)
                return;

        /* don't do anything if debug user changed role to not OTG */
        if (dwc->current_dr_role != DWC3_GCTL_PRTCAP_OTG)
                return;

        if (!ignore_idstatus) {
                reg = dwc3_readl(dwc, DWC3_OSTS);
                id = !!(reg & DWC3_OSTS_CONIDSTS);

                dwc->desired_otg_role = id ? DWC3_OTG_ROLE_DEVICE :
                                        DWC3_OTG_ROLE_HOST;
        }

        if (dwc->desired_otg_role == dwc->current_otg_role)
                return;

        switch (dwc->current_otg_role) {
        case DWC3_OTG_ROLE_HOST:
                dwc3_host_exit(dwc);
                spin_lock_irqsave(&dwc->lock, flags);
                dwc3_otg_host_exit(dwc);
                spin_unlock_irqrestore(&dwc->lock, flags);
                break;
        case DWC3_OTG_ROLE_DEVICE:
                dwc3_gadget_exit(dwc);
                spin_lock_irqsave(&dwc->lock, flags);
                dwc3_event_buffers_cleanup(dwc);
                dwc3_otg_device_exit(dwc);
                spin_unlock_irqrestore(&dwc->lock, flags);
                break;
        default:
                break;
        }

        spin_lock_irqsave(&dwc->lock, flags);

        dwc->current_otg_role = dwc->desired_otg_role;

        spin_unlock_irqrestore(&dwc->lock, flags);

        switch (dwc->desired_otg_role) {
        case DWC3_OTG_ROLE_HOST:
                spin_lock_irqsave(&dwc->lock, flags);
                dwc3_otgregs_init(dwc);
                dwc3_otg_host_init(dwc);
                spin_unlock_irqrestore(&dwc->lock, flags);
                dwc3_pre_set_role(dwc, USB_ROLE_HOST);
                ret = dwc3_host_init(dwc);
                if (ret) {
                        dev_err(dwc->dev, "failed to initialize host\n");
                } else {
                        if (dwc->usb2_phy)
                                otg_set_vbus(dwc->usb2_phy->otg, true);
                        for (i = 0; i < dwc->num_usb2_ports; i++) {
                                if (dwc->usb2_generic_phy[i]) {
                                        phy_set_mode(dwc->usb2_generic_phy[i],
                                                     PHY_MODE_USB_HOST);
                                }
                        }
                }
                break;
        case DWC3_OTG_ROLE_DEVICE:
                spin_lock_irqsave(&dwc->lock, flags);
                dwc3_otgregs_init(dwc);
                dwc3_otg_device_init(dwc);
                dwc3_event_buffers_setup(dwc);
                spin_unlock_irqrestore(&dwc->lock, flags);

                if (dwc->usb2_phy)
                        otg_set_vbus(dwc->usb2_phy->otg, false);
                if (dwc->usb2_generic_phy[0])
                        phy_set_mode(dwc->usb2_generic_phy[0], PHY_MODE_USB_DEVICE);
                dwc3_pre_set_role(dwc, USB_ROLE_DEVICE);
                ret = dwc3_gadget_init(dwc);
                if (ret)
                        dev_err(dwc->dev, "failed to initialize peripheral\n");
                break;
        default:
                break;
        }
}

static void dwc3_drd_update(struct dwc3 *dwc)
{
        int id;

        if (dwc->edev) {
                id = extcon_get_state(dwc->edev, EXTCON_USB_HOST);
                if (id < 0)
                        id = 0;
                dwc3_set_mode(dwc, id ?
                              DWC3_GCTL_PRTCAP_HOST :
                              DWC3_GCTL_PRTCAP_DEVICE);
        }
}

static int dwc3_drd_notifier(struct notifier_block *nb,
                             unsigned long event, void *ptr)
{
        struct dwc3 *dwc = container_of(nb, struct dwc3, edev_nb);
        u32 mode = event ? DWC3_GCTL_PRTCAP_HOST : DWC3_GCTL_PRTCAP_DEVICE;
        enum usb_role role = mode == DWC3_GCTL_PRTCAP_HOST ?
                                     USB_ROLE_HOST : USB_ROLE_DEVICE;

        dwc3_pre_set_role(dwc, role);
        dwc3_set_mode(dwc, mode);

        return NOTIFY_DONE;
}

#if IS_ENABLED(CONFIG_USB_ROLE_SWITCH)
#define ROLE_SWITCH 1
static int dwc3_usb_role_switch_set(struct usb_role_switch *sw,
                                    enum usb_role role)
{
        struct dwc3 *dwc = usb_role_switch_get_drvdata(sw);
        u32 mode;

        switch (role) {
        case USB_ROLE_HOST:
                mode = DWC3_GCTL_PRTCAP_HOST;
                break;
        case USB_ROLE_DEVICE:
                mode = DWC3_GCTL_PRTCAP_DEVICE;
                break;
        default:
                if (dwc->role_switch_default_mode == USB_DR_MODE_HOST)
                        mode = DWC3_GCTL_PRTCAP_HOST;
                else
                        mode = DWC3_GCTL_PRTCAP_DEVICE;
                break;
        }

        dwc3_pre_set_role(dwc, role);
        dwc3_set_mode(dwc, mode);
        return 0;
}

static enum usb_role dwc3_usb_role_switch_get(struct usb_role_switch *sw)
{
        struct dwc3 *dwc = usb_role_switch_get_drvdata(sw);
        unsigned long flags;
        enum usb_role role;

        spin_lock_irqsave(&dwc->lock, flags);
        switch (dwc->current_dr_role) {
        case DWC3_GCTL_PRTCAP_HOST:
                role = USB_ROLE_HOST;
                break;
        case DWC3_GCTL_PRTCAP_DEVICE:
                role = USB_ROLE_DEVICE;
                break;
        case DWC3_GCTL_PRTCAP_OTG:
                role = dwc->current_otg_role;
                break;
        default:
                if (dwc->role_switch_default_mode == USB_DR_MODE_HOST)
                        role = USB_ROLE_HOST;
                else
                        role = USB_ROLE_DEVICE;
                break;
        }
        spin_unlock_irqrestore(&dwc->lock, flags);
        return role;
}

static int dwc3_setup_role_switch(struct dwc3 *dwc)
{
        struct usb_role_switch_desc dwc3_role_switch = {NULL};
        u32 mode;

        dwc->role_switch_default_mode = usb_get_role_switch_default_mode(dwc->dev);
        if (dwc->role_switch_default_mode == USB_DR_MODE_HOST) {
                mode = DWC3_GCTL_PRTCAP_HOST;
        } else {
                dwc->role_switch_default_mode = USB_DR_MODE_PERIPHERAL;
                mode = DWC3_GCTL_PRTCAP_DEVICE;
        }
        dwc3_set_mode(dwc, mode);

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

        if (dwc->dev->of_node) {
                /* populate connector entry */
                int ret = devm_of_platform_populate(dwc->dev);

                if (ret) {
                        usb_role_switch_unregister(dwc->role_sw);
                        dwc->role_sw = NULL;
                        dev_err(dwc->dev, "DWC3 platform devices creation failed: %i\n", ret);
                        return ret;
                }
        }

        return 0;
}
#else
#define ROLE_SWITCH 0
#define dwc3_setup_role_switch(x) 0
#endif

int dwc3_drd_init(struct dwc3 *dwc)
{
        int ret, irq;

        if (ROLE_SWITCH &&
            device_property_read_bool(dwc->dev, "usb-role-switch"))
                return dwc3_setup_role_switch(dwc);

        if (dwc->edev) {
                dwc->edev_nb.notifier_call = dwc3_drd_notifier;
                ret = extcon_register_notifier(dwc->edev, EXTCON_USB_HOST,
                                               &dwc->edev_nb);
                if (ret < 0) {
                        dev_err(dwc->dev, "couldn't register cable notifier\n");
                        return ret;
                }

                dwc3_drd_update(dwc);
        } else {
                dwc3_set_prtcap(dwc, DWC3_GCTL_PRTCAP_OTG, true);

                /* use OTG block to get ID event */
                irq = dwc3_otg_get_irq(dwc);
                if (irq < 0)
                        return irq;

                dwc->otg_irq = irq;

                /* disable all OTG IRQs */
                dwc3_otg_disable_events(dwc, DWC3_OTG_ALL_EVENTS);
                /* clear all events */
                dwc3_otg_clear_events(dwc);

                ret = request_threaded_irq(dwc->otg_irq, dwc3_otg_irq,
                                           dwc3_otg_thread_irq,
                                           IRQF_SHARED, "dwc3-otg", dwc);
                if (ret) {
                        dev_err(dwc->dev, "failed to request irq #%d --> %d\n",
                                dwc->otg_irq, ret);
                        ret = -ENODEV;
                        return ret;
                }

                dwc3_otg_init(dwc);
                dwc3_set_mode(dwc, DWC3_GCTL_PRTCAP_OTG);
        }

        return 0;
}

void dwc3_drd_exit(struct dwc3 *dwc)
{
        unsigned long flags;

        if (dwc->role_sw)
                usb_role_switch_unregister(dwc->role_sw);

        if (dwc->edev)
                extcon_unregister_notifier(dwc->edev, EXTCON_USB_HOST,
                                           &dwc->edev_nb);

        cancel_work_sync(&dwc->drd_work);

        /* debug user might have changed role, clean based on current role */
        switch (dwc->current_dr_role) {
        case DWC3_GCTL_PRTCAP_HOST:
                dwc3_host_exit(dwc);
                break;
        case DWC3_GCTL_PRTCAP_DEVICE:
                dwc3_gadget_exit(dwc);
                dwc3_event_buffers_cleanup(dwc);
                break;
        case DWC3_GCTL_PRTCAP_OTG:
                dwc3_otg_exit(dwc);
                spin_lock_irqsave(&dwc->lock, flags);
                dwc->desired_otg_role = DWC3_OTG_ROLE_IDLE;
                spin_unlock_irqrestore(&dwc->lock, flags);
                dwc3_otg_update(dwc, 1);
                break;
        default:
                break;
        }

        if (dwc->otg_irq)
                free_irq(dwc->otg_irq, dwc);
}