// SPDX-License-Identifier: GPL-2.0
/*
 * Cadence USBSS and USBSSP DRD Driver.
 *
 * Copyright (C) 2018-2019 Cadence.
 * Copyright (C) 2017-2018 NXP
 * Copyright (C) 2019 Texas Instruments
 *
 * Author: Peter Chen <peter.chen@nxp.com>
 *         Pawel Laszczak <pawell@cadence.com>
 *         Roger Quadros <rogerq@ti.com>
 */

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

#include "core.h"
#include "host-export.h"
#include "drd.h"

static int cdns_idle_init(struct cdns *cdns);

static int cdns_role_start(struct cdns *cdns, enum usb_role role)
{
        int ret;

        if (WARN_ON(role > USB_ROLE_DEVICE))
                return 0;

        mutex_lock(&cdns->mutex);
        cdns->role = role;
        mutex_unlock(&cdns->mutex);

        if (!cdns->roles[role])
                return -ENXIO;

        if (cdns->roles[role]->state == CDNS_ROLE_STATE_ACTIVE)
                return 0;

        mutex_lock(&cdns->mutex);
        ret = cdns->roles[role]->start(cdns);
        if (!ret)
                cdns->roles[role]->state = CDNS_ROLE_STATE_ACTIVE;
        mutex_unlock(&cdns->mutex);

        return ret;
}

static void cdns_role_stop(struct cdns *cdns)
{
        enum usb_role role = cdns->role;

        if (WARN_ON(role > USB_ROLE_DEVICE))
                return;

        if (cdns->roles[role]->state == CDNS_ROLE_STATE_INACTIVE)
                return;

        mutex_lock(&cdns->mutex);
        cdns->roles[role]->stop(cdns);
        cdns->roles[role]->state = CDNS_ROLE_STATE_INACTIVE;
        mutex_unlock(&cdns->mutex);
}

static void cdns_exit_roles(struct cdns *cdns)
{
        cdns_role_stop(cdns);
        cdns_drd_exit(cdns);
}

/**
 * cdns_core_init_role - initialize role of operation
 * @cdns: Pointer to cdns structure
 *
 * Returns 0 on success otherwise negative errno
 */
static int cdns_core_init_role(struct cdns *cdns)
{
        struct device *dev = cdns->dev;
        enum usb_dr_mode best_dr_mode;
        enum usb_dr_mode dr_mode;
        int ret;

        dr_mode = usb_get_dr_mode(dev);
        cdns->role = USB_ROLE_NONE;

        /*
         * If driver can't read mode by means of usb_get_dr_mode function then
         * chooses mode according with Kernel configuration. This setting
         * can be restricted later depending on strap pin configuration.
         */
        if (dr_mode == USB_DR_MODE_UNKNOWN) {
                if (cdns->version == CDNSP_CONTROLLER_V2) {
                        if (IS_ENABLED(CONFIG_USB_CDNSP_HOST) &&
                            IS_ENABLED(CONFIG_USB_CDNSP_GADGET))
                                dr_mode = USB_DR_MODE_OTG;
                        else if (IS_ENABLED(CONFIG_USB_CDNSP_HOST))
                                dr_mode = USB_DR_MODE_HOST;
                        else if (IS_ENABLED(CONFIG_USB_CDNSP_GADGET))
                                dr_mode = USB_DR_MODE_PERIPHERAL;
                } else {
                        if (IS_ENABLED(CONFIG_USB_CDNS3_HOST) &&
                            IS_ENABLED(CONFIG_USB_CDNS3_GADGET))
                                dr_mode = USB_DR_MODE_OTG;
                        else if (IS_ENABLED(CONFIG_USB_CDNS3_HOST))
                                dr_mode = USB_DR_MODE_HOST;
                        else if (IS_ENABLED(CONFIG_USB_CDNS3_GADGET))
                                dr_mode = USB_DR_MODE_PERIPHERAL;
                }
        }

        /*
         * At this point cdns->dr_mode contains strap configuration.
         * Driver try update this setting considering kernel configuration
         */
        best_dr_mode = cdns->dr_mode;

        ret = cdns_idle_init(cdns);
        if (ret)
                return ret;

        if (dr_mode == USB_DR_MODE_OTG) {
                best_dr_mode = cdns->dr_mode;
        } else if (cdns->dr_mode == USB_DR_MODE_OTG) {
                best_dr_mode = dr_mode;
        } else if (cdns->dr_mode != dr_mode) {
                dev_err(dev, "Incorrect DRD configuration\n");
                return -EINVAL;
        }

        dr_mode = best_dr_mode;

        if (dr_mode == USB_DR_MODE_OTG || dr_mode == USB_DR_MODE_HOST) {
                if ((cdns->version == CDNSP_CONTROLLER_V2 &&
                     IS_ENABLED(CONFIG_USB_CDNSP_HOST)) ||
                    (cdns->version < CDNSP_CONTROLLER_V2 &&
                     IS_ENABLED(CONFIG_USB_CDNS3_HOST)))
                        ret = cdns_host_init(cdns);
                else
                        ret = -ENXIO;

                if (ret) {
                        dev_err(dev, "Host initialization failed with %d\n",
                                ret);
                        goto err;
                }
        }

        if (dr_mode == USB_DR_MODE_OTG || dr_mode == USB_DR_MODE_PERIPHERAL) {
                if (cdns->gadget_init)
                        ret = cdns->gadget_init(cdns);
                else
                        ret = -ENXIO;

                if (ret) {
                        dev_err(dev, "Device initialization failed with %d\n",
                                ret);
                        goto err;
                }
        }

        cdns->dr_mode = dr_mode;

        ret = cdns_drd_update_mode(cdns);
        if (ret)
                goto err;

        /* Initialize idle role to start with */
        ret = cdns_role_start(cdns, USB_ROLE_NONE);
        if (ret)
                goto err;

        switch (cdns->dr_mode) {
        case USB_DR_MODE_OTG:
                ret = cdns_hw_role_switch(cdns);
                if (ret)
                        goto err;
                break;
        case USB_DR_MODE_PERIPHERAL:
                ret = cdns_role_start(cdns, USB_ROLE_DEVICE);
                if (ret)
                        goto err;
                break;
        case USB_DR_MODE_HOST:
                ret = cdns_role_start(cdns, USB_ROLE_HOST);
                if (ret)
                        goto err;
                break;
        default:
                ret = -EINVAL;
                goto err;
        }

        return 0;
err:
        cdns_exit_roles(cdns);
        return ret;
}

/**
 * cdns_hw_role_state_machine  - role switch state machine based on hw events.
 * @cdns: Pointer to controller structure.
 *
 * Returns next role to be entered based on hw events.
 */
static enum usb_role cdns_hw_role_state_machine(struct cdns *cdns)
{
        enum usb_role role = USB_ROLE_NONE;
        int id, vbus;

        if (cdns->dr_mode != USB_DR_MODE_OTG) {
                if (cdns_is_host(cdns))
                        role = USB_ROLE_HOST;
                if (cdns_is_device(cdns))
                        role = USB_ROLE_DEVICE;

                return role;
        }

        id = cdns_get_id(cdns);
        vbus = cdns_get_vbus(cdns);

        /*
         * Role change state machine
         * Inputs: ID, VBUS
         * Previous state: cdns->role
         * Next state: role
         */
        role = cdns->role;

        switch (role) {
        case USB_ROLE_NONE:
                /*
                 * Driver treats USB_ROLE_NONE synonymous to IDLE state from
                 * controller specification.
                 */
                if (!id)
                        role = USB_ROLE_HOST;
                else if (vbus)
                        role = USB_ROLE_DEVICE;
                break;
        case USB_ROLE_HOST: /* from HOST, we can only change to NONE */
                if (id)
                        role = USB_ROLE_NONE;
                break;
        case USB_ROLE_DEVICE: /* from GADGET, we can only change to NONE*/
                if (!vbus)
                        role = USB_ROLE_NONE;
                break;
        }

        dev_dbg(cdns->dev, "role %d -> %d\n", cdns->role, role);

        return role;
}

static int cdns_idle_role_start(struct cdns *cdns)
{
        return 0;
}

static void cdns_idle_role_stop(struct cdns *cdns)
{
        /* Program Lane swap and bring PHY out of RESET */
        phy_reset(cdns->usb3_phy);
}

static int cdns_idle_init(struct cdns *cdns)
{
        struct cdns_role_driver *rdrv;

        rdrv = devm_kzalloc(cdns->dev, sizeof(*rdrv), GFP_KERNEL);
        if (!rdrv)
                return -ENOMEM;

        rdrv->start = cdns_idle_role_start;
        rdrv->stop = cdns_idle_role_stop;
        rdrv->state = CDNS_ROLE_STATE_INACTIVE;
        rdrv->suspend = NULL;
        rdrv->resume = NULL;
        rdrv->name = "idle";

        cdns->roles[USB_ROLE_NONE] = rdrv;

        return 0;
}

/**
 * cdns_hw_role_switch - switch roles based on HW state
 * @cdns: controller
 */
int cdns_hw_role_switch(struct cdns *cdns)
{
        enum usb_role real_role, current_role;
        int ret = 0;

        /* Depends on role switch class */
        if (cdns->role_sw)
                return 0;

        pm_runtime_get_sync(cdns->dev);

        current_role = cdns->role;
        real_role = cdns_hw_role_state_machine(cdns);

        /* Do nothing if nothing changed */
        if (current_role == real_role)
                goto exit;

        cdns_role_stop(cdns);

        dev_dbg(cdns->dev, "Switching role %d -> %d", current_role, real_role);

        ret = cdns_role_start(cdns, real_role);
        if (ret) {
                /* Back to current role */
                dev_err(cdns->dev, "set %d has failed, back to %d\n",
                        real_role, current_role);
                ret = cdns_role_start(cdns, current_role);
                if (ret)
                        dev_err(cdns->dev, "back to %d failed too\n",
                                current_role);
        }
exit:
        pm_runtime_put_sync(cdns->dev);
        return ret;
}

/**
 * cdns_role_get - get current role of controller.
 *
 * @sw: pointer to USB role switch structure
 *
 * Returns role
 */
static enum usb_role cdns_role_get(struct usb_role_switch *sw)
{
        struct cdns *cdns = usb_role_switch_get_drvdata(sw);

        return cdns->role;
}

/**
 * cdns_role_set - set current role of controller.
 *
 * @sw: pointer to USB role switch structure
 * @role: the previous role
 * Handles below events:
 * - Role switch for dual-role devices
 * - USB_ROLE_GADGET <--> USB_ROLE_NONE for peripheral-only devices
 */
static int cdns_role_set(struct usb_role_switch *sw, enum usb_role role)
{
        struct cdns *cdns = usb_role_switch_get_drvdata(sw);
        int ret = 0;

        pm_runtime_get_sync(cdns->dev);

        if (cdns->role == role)
                goto pm_put;

        if (cdns->dr_mode == USB_DR_MODE_HOST) {
                switch (role) {
                case USB_ROLE_NONE:
                case USB_ROLE_HOST:
                        break;
                default:
                        goto pm_put;
                }
        }

        if (cdns->dr_mode == USB_DR_MODE_PERIPHERAL) {
                switch (role) {
                case USB_ROLE_NONE:
                case USB_ROLE_DEVICE:
                        break;
                default:
                        goto pm_put;
                }
        }

        cdns_role_stop(cdns);
        ret = cdns_role_start(cdns, role);
        if (ret)
                dev_err(cdns->dev, "set role %d has failed\n", role);

pm_put:
        pm_runtime_put_sync(cdns->dev);
        return ret;
}

/**
 * cdns_wakeup_irq - interrupt handler for wakeup events
 * @irq: irq number for cdns3/cdnsp core device
 * @data: structure of cdns
 *
 * Returns IRQ_HANDLED or IRQ_NONE
 */
static irqreturn_t cdns_wakeup_irq(int irq, void *data)
{
        struct cdns *cdns = data;

        if (cdns->in_lpm) {
                disable_irq_nosync(irq);
                cdns->wakeup_pending = true;
                if ((cdns->role == USB_ROLE_HOST) && cdns->host_dev)
                        pm_request_resume(&cdns->host_dev->dev);

                return IRQ_HANDLED;
        }

        return IRQ_NONE;
}

/**
 * cdns_init - probe for cdns3/cdnsp core device
 * @cdns: Pointer to cdns structure.
 *
 * Returns 0 on success otherwise negative errno
 */
int cdns_init(struct cdns *cdns)
{
        struct device *dev = cdns->dev;
        int ret;

        ret = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(32));
        if (ret) {
                dev_err(dev, "error setting dma mask: %d\n", ret);
                return ret;
        }

        mutex_init(&cdns->mutex);

        if (device_property_read_bool(dev, "usb-role-switch")) {
                struct usb_role_switch_desc sw_desc = { };

                sw_desc.set = cdns_role_set;
                sw_desc.get = cdns_role_get;
                sw_desc.allow_userspace_control = true;
                sw_desc.driver_data = cdns;
                sw_desc.fwnode = dev->fwnode;

                cdns->role_sw = usb_role_switch_register(dev, &sw_desc);
                if (IS_ERR(cdns->role_sw)) {
                        dev_warn(dev, "Unable to register Role Switch\n");
                        return PTR_ERR(cdns->role_sw);
                }
        }

        if (cdns->wakeup_irq) {
                ret = devm_request_irq(cdns->dev, cdns->wakeup_irq,
                                                cdns_wakeup_irq,
                                                IRQF_SHARED,
                                                dev_name(cdns->dev), cdns);

                if (ret) {
                        dev_err(cdns->dev, "couldn't register wakeup irq handler\n");
                        goto role_switch_unregister;
                }
        }

        ret = cdns_drd_init(cdns);
        if (ret)
                goto init_failed;

        ret = cdns_core_init_role(cdns);
        if (ret)
                goto init_failed;

        spin_lock_init(&cdns->lock);

        dev_dbg(dev, "Cadence USB3 core: probe succeed\n");

        return 0;
init_failed:
        cdns_drd_exit(cdns);
role_switch_unregister:
        if (cdns->role_sw)
                usb_role_switch_unregister(cdns->role_sw);

        return ret;
}
EXPORT_SYMBOL_GPL(cdns_init);

/**
 * cdns_remove - unbind drd driver and clean up
 * @cdns: Pointer to cdns structure.
 *
 * Returns 0 on success otherwise negative errno
 */
int cdns_remove(struct cdns *cdns)
{
        cdns_exit_roles(cdns);
        usb_role_switch_unregister(cdns->role_sw);

        return 0;
}
EXPORT_SYMBOL_GPL(cdns_remove);

#ifdef CONFIG_PM_SLEEP
int cdns_suspend(struct cdns *cdns)
{
        struct device *dev = cdns->dev;
        unsigned long flags;

        if (pm_runtime_status_suspended(dev))
                pm_runtime_resume(dev);

        if (cdns->roles[cdns->role]->suspend) {
                spin_lock_irqsave(&cdns->lock, flags);
                cdns->roles[cdns->role]->suspend(cdns, false);
                spin_unlock_irqrestore(&cdns->lock, flags);
        }

        return 0;
}
EXPORT_SYMBOL_GPL(cdns_suspend);

int cdns_resume(struct cdns *cdns)
{
        bool power_lost = cdns_power_is_lost(cdns);
        enum usb_role real_role;
        bool role_changed = false;
        int ret = 0;

        if (power_lost) {
                if (!cdns->role_sw) {
                        real_role = cdns_hw_role_state_machine(cdns);
                        if (real_role != cdns->role) {
                                ret = cdns_hw_role_switch(cdns);
                                if (ret)
                                        return ret;
                                role_changed = true;
                        }
                }

                if (!role_changed) {
                        if (cdns->role == USB_ROLE_HOST)
                                ret = cdns_drd_host_on(cdns);
                        else if (cdns->role == USB_ROLE_DEVICE)
                                ret = cdns_drd_gadget_on(cdns);

                        if (ret)
                                return ret;
                }
        }

        if (!role_changed && cdns->roles[cdns->role]->resume)
                cdns->roles[cdns->role]->resume(cdns, power_lost);

        return 0;
}
EXPORT_SYMBOL_GPL(cdns_resume);

void cdns_set_active(struct cdns *cdns, u8 set_active)
{
        struct device *dev = cdns->dev;

        if (set_active) {
                pm_runtime_disable(dev);
                pm_runtime_set_active(dev);
                pm_runtime_enable(dev);
        }

        return;
}
EXPORT_SYMBOL_GPL(cdns_set_active);
#endif /* CONFIG_PM_SLEEP */

MODULE_AUTHOR("Peter Chen <peter.chen@nxp.com>");
MODULE_AUTHOR("Pawel Laszczak <pawell@cadence.com>");
MODULE_AUTHOR("Roger Quadros <rogerq@ti.com>");
MODULE_DESCRIPTION("Cadence USBSS and USBSSP DRD Driver");
MODULE_LICENSE("GPL");