// SPDX-License-Identifier: GPL-2.0
/*
 * Cadence USBSS 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/platform_device.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/pm_runtime.h>

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

static int cdns3_idle_init(struct cdns3 *cdns);

static inline
struct cdns3_role_driver *cdns3_get_current_role_driver(struct cdns3 *cdns)
{
        WARN_ON(!cdns->roles[cdns->role]);
        return cdns->roles[cdns->role];
}

static int cdns3_role_start(struct cdns3 *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 == CDNS3_ROLE_STATE_ACTIVE)
                return 0;

        mutex_lock(&cdns->mutex);
        ret = cdns->roles[role]->start(cdns);
        if (!ret)
                cdns->roles[role]->state = CDNS3_ROLE_STATE_ACTIVE;
        mutex_unlock(&cdns->mutex);

        return ret;
}

static void cdns3_role_stop(struct cdns3 *cdns)
{
        enum usb_role role = cdns->role;

        if (WARN_ON(role > USB_ROLE_DEVICE))
                return;

        if (cdns->roles[role]->state == CDNS3_ROLE_STATE_INACTIVE)
                return;

        mutex_lock(&cdns->mutex);
        cdns->roles[role]->stop(cdns);
        cdns->roles[role]->state = CDNS3_ROLE_STATE_INACTIVE;
        mutex_unlock(&cdns->mutex);
}

static void cdns3_exit_roles(struct cdns3 *cdns)
{
        cdns3_role_stop(cdns);
        cdns3_drd_exit(cdns);
}

static enum usb_role cdsn3_hw_role_state_machine(struct cdns3 *cdns);

/**
 * cdns3_core_init_role - initialize role of operation
 * @cdns: Pointer to cdns3 structure
 *
 * Returns 0 on success otherwise negative errno
 */
static int cdns3_core_init_role(struct cdns3 *cdns)
{
        struct device *dev = cdns->dev;
        enum usb_dr_mode best_dr_mode;
        enum usb_dr_mode dr_mode;
        int ret = 0;

        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 (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 = cdns3_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) {
                ret = cdns3_host_init(cdns);
                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) {
                ret = cdns3_gadget_init(cdns);
                if (ret) {
                        dev_err(dev, "Device initialization failed with %d\n",
                                ret);
                        goto err;
                }
        }

        cdns->dr_mode = dr_mode;

        ret = cdns3_drd_update_mode(cdns);
        if (ret)
                goto err;

        /* Initialize idle role to start with */
        ret = cdns3_role_start(cdns, USB_ROLE_NONE);
        if (ret)
                goto err;

        switch (cdns->dr_mode) {
        case USB_DR_MODE_OTG:
                ret = cdns3_hw_role_switch(cdns);
                if (ret)
                        goto err;
                break;
        case USB_DR_MODE_PERIPHERAL:
                ret = cdns3_role_start(cdns, USB_ROLE_DEVICE);
                if (ret)
                        goto err;
                break;
        case USB_DR_MODE_HOST:
                ret = cdns3_role_start(cdns, USB_ROLE_HOST);
                if (ret)
                        goto err;
                break;
        default:
                ret = -EINVAL;
                goto err;
        }

        return ret;
err:
        cdns3_exit_roles(cdns);
        return ret;
}

/**
 * cdsn3_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 cdsn3_hw_role_state_machine(struct cdns3 *cdns)
{
        enum usb_role role;
        int id, vbus;

        if (cdns->dr_mode != USB_DR_MODE_OTG)
                goto not_otg;

        id = cdns3_get_id(cdns);
        vbus = cdns3_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;

not_otg:
        if (cdns3_is_host(cdns))
                role = USB_ROLE_HOST;
        if (cdns3_is_device(cdns))
                role = USB_ROLE_DEVICE;

        return role;
}

static int cdns3_idle_role_start(struct cdns3 *cdns)
{
        return 0;
}

static void cdns3_idle_role_stop(struct cdns3 *cdns)
{
        /* Program Lane swap and bring PHY out of RESET */
        phy_reset(cdns->usb3_phy);
}

static int cdns3_idle_init(struct cdns3 *cdns)
{
        struct cdns3_role_driver *rdrv;

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

        rdrv->start = cdns3_idle_role_start;
        rdrv->stop = cdns3_idle_role_stop;
        rdrv->state = CDNS3_ROLE_STATE_INACTIVE;
        rdrv->suspend = NULL;
        rdrv->resume = NULL;
        rdrv->name = "idle";

        cdns->roles[USB_ROLE_NONE] = rdrv;

        return 0;
}

/**
 * cdns3_hw_role_switch - switch roles based on HW state
 * @cdns3: controller
 */
int cdns3_hw_role_switch(struct cdns3 *cdns)
{
        enum usb_role real_role, current_role;
        int ret = 0;

        /* Do nothing if role based on syfs. */
        if (cdns->role_override)
                return 0;

        pm_runtime_get_sync(cdns->dev);

        current_role = cdns->role;
        real_role = cdsn3_hw_role_state_machine(cdns);

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

        cdns3_role_stop(cdns);

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

        ret = cdns3_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 = cdns3_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;
}

/**
 * cdsn3_role_get - get current role of controller.
 *
 * @dev: Pointer to device structure
 *
 * Returns role
 */
static enum usb_role cdns3_role_get(struct usb_role_switch *sw)
{
        struct cdns3 *cdns = usb_role_switch_get_drvdata(sw);

        return cdns->role;
}

/**
 * cdns3_role_set - set current role of controller.
 *
 * @dev: pointer to device object
 * @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 cdns3_role_set(struct usb_role_switch *sw, enum usb_role role)
{
        struct cdns3 *cdns = usb_role_switch_get_drvdata(sw);
        int ret = 0;

        pm_runtime_get_sync(cdns->dev);

        /*
         * FIXME: switch role framework should be extended to meet
         * requirements. Driver assumes that role can be controlled
         * by SW or HW. Temporary workaround is to use USB_ROLE_NONE to
         * switch from SW to HW control.
         *
         * For dr_mode == USB_DR_MODE_OTG:
         *      if user sets USB_ROLE_HOST or USB_ROLE_DEVICE then driver
         *      sets role_override flag and forces that role.
         *      if user sets USB_ROLE_NONE, driver clears role_override and lets
         *      HW state machine take over.
         *
         * For dr_mode != USB_DR_MODE_OTG:
         *      Assumptions:
         *      1. Restricted user control between NONE and dr_mode.
         *      2. Driver doesn't need to rely on role_override flag.
         *      3. Driver needs to ensure that HW state machine is never called
         *         if dr_mode != USB_DR_MODE_OTG.
         */
        if (role == USB_ROLE_NONE)
                cdns->role_override = 0;
        else
                cdns->role_override = 1;

        /*
         * HW state might have changed so driver need to trigger
         * HW state machine if dr_mode == USB_DR_MODE_OTG.
         */
        if (!cdns->role_override && cdns->dr_mode == USB_DR_MODE_OTG) {
                cdns3_hw_role_switch(cdns);
                goto pm_put;
        }

        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:
                        ret = -EPERM;
                        goto pm_put;
                }
        }

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

        cdns3_role_stop(cdns);
        ret = cdns3_role_start(cdns, role);
        if (ret) {
                dev_err(cdns->dev, "set role %d has failed\n", role);
                ret = -EPERM;
        }

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

/**
 * cdns3_probe - probe for cdns3 core device
 * @pdev: Pointer to cdns3 core platform device
 *
 * Returns 0 on success otherwise negative errno
 */
static int cdns3_probe(struct platform_device *pdev)
{
        struct usb_role_switch_desc sw_desc = { };
        struct device *dev = &pdev->dev;
        struct resource *res;
        struct cdns3 *cdns;
        void __iomem *regs;
        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 -ENODEV;
        }

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

        cdns->dev = dev;

        platform_set_drvdata(pdev, cdns);

        res = platform_get_resource_byname(pdev, IORESOURCE_IRQ, "host");
        if (!res) {
                dev_err(dev, "missing host IRQ\n");
                return -ENODEV;
        }

        cdns->xhci_res[0] = *res;

        res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "xhci");
        if (!res) {
                dev_err(dev, "couldn't get xhci resource\n");
                return -ENXIO;
        }

        cdns->xhci_res[1] = *res;

        cdns->dev_irq = platform_get_irq_byname(pdev, "peripheral");
        if (cdns->dev_irq == -EPROBE_DEFER)
                return cdns->dev_irq;

        if (cdns->dev_irq < 0)
                dev_err(dev, "couldn't get peripheral irq\n");

        res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dev");
        regs = devm_ioremap_resource(dev, res);
        if (IS_ERR(regs))
                return PTR_ERR(regs);
        cdns->dev_regs  = regs;

        cdns->otg_irq = platform_get_irq_byname(pdev, "otg");
        if (cdns->otg_irq == -EPROBE_DEFER)
                return cdns->otg_irq;

        if (cdns->otg_irq < 0) {
                dev_err(dev, "couldn't get otg irq\n");
                return cdns->otg_irq;
        }

        res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "otg");
        if (!res) {
                dev_err(dev, "couldn't get otg resource\n");
                return -ENXIO;
        }

        cdns->otg_res = *res;

        mutex_init(&cdns->mutex);

        cdns->usb2_phy = devm_phy_optional_get(dev, "cdns3,usb2-phy");
        if (IS_ERR(cdns->usb2_phy))
                return PTR_ERR(cdns->usb2_phy);

        ret = phy_init(cdns->usb2_phy);
        if (ret)
                return ret;

        cdns->usb3_phy = devm_phy_optional_get(dev, "cdns3,usb3-phy");
        if (IS_ERR(cdns->usb3_phy))
                return PTR_ERR(cdns->usb3_phy);

        ret = phy_init(cdns->usb3_phy);
        if (ret)
                goto err1;

        ret = phy_power_on(cdns->usb2_phy);
        if (ret)
                goto err2;

        ret = phy_power_on(cdns->usb3_phy);
        if (ret)
                goto err3;

        sw_desc.set = cdns3_role_set;
        sw_desc.get = cdns3_role_get;
        sw_desc.allow_userspace_control = true;
        sw_desc.driver_data = cdns;

        cdns->role_sw = usb_role_switch_register(dev, &sw_desc);
        if (IS_ERR(cdns->role_sw)) {
                ret = PTR_ERR(cdns->role_sw);
                dev_warn(dev, "Unable to register Role Switch\n");
                goto err4;
        }

        ret = cdns3_drd_init(cdns);
        if (ret)
                goto err5;

        ret = cdns3_core_init_role(cdns);
        if (ret)
                goto err5;

        device_set_wakeup_capable(dev, true);
        pm_runtime_set_active(dev);
        pm_runtime_enable(dev);

        /*
         * The controller needs less time between bus and controller suspend,
         * and we also needs a small delay to avoid frequently entering low
         * power mode.
         */
        pm_runtime_set_autosuspend_delay(dev, 20);
        pm_runtime_mark_last_busy(dev);
        pm_runtime_use_autosuspend(dev);
        dev_dbg(dev, "Cadence USB3 core: probe succeed\n");

        return 0;
err5:
        cdns3_drd_exit(cdns);
        usb_role_switch_unregister(cdns->role_sw);
err4:
        phy_power_off(cdns->usb3_phy);

err3:
        phy_power_off(cdns->usb2_phy);
err2:
        phy_exit(cdns->usb3_phy);
err1:
        phy_exit(cdns->usb2_phy);

        return ret;
}

/**
 * cdns3_remove - unbind drd driver and clean up
 * @pdev: Pointer to Linux platform device
 *
 * Returns 0 on success otherwise negative errno
 */
static int cdns3_remove(struct platform_device *pdev)
{
        struct cdns3 *cdns = platform_get_drvdata(pdev);

        pm_runtime_get_sync(&pdev->dev);
        pm_runtime_disable(&pdev->dev);
        pm_runtime_put_noidle(&pdev->dev);
        cdns3_exit_roles(cdns);
        usb_role_switch_unregister(cdns->role_sw);
        phy_power_off(cdns->usb2_phy);
        phy_power_off(cdns->usb3_phy);
        phy_exit(cdns->usb2_phy);
        phy_exit(cdns->usb3_phy);
        return 0;
}

#ifdef CONFIG_PM_SLEEP

static int cdns3_suspend(struct device *dev)
{
        struct cdns3 *cdns = dev_get_drvdata(dev);
        unsigned long flags;

        if (cdns->role == USB_ROLE_HOST)
                return 0;

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

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

        return 0;
}

static int cdns3_resume(struct device *dev)
{
        struct cdns3 *cdns = dev_get_drvdata(dev);
        unsigned long flags;

        if (cdns->role == USB_ROLE_HOST)
                return 0;

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

        pm_runtime_disable(dev);
        pm_runtime_set_active(dev);
        pm_runtime_enable(dev);

        return 0;
}
#endif

static const struct dev_pm_ops cdns3_pm_ops = {
        SET_SYSTEM_SLEEP_PM_OPS(cdns3_suspend, cdns3_resume)
};

#ifdef CONFIG_OF
static const struct of_device_id of_cdns3_match[] = {
        { .compatible = "cdns,usb3" },
        { },
};
MODULE_DEVICE_TABLE(of, of_cdns3_match);
#endif

static struct platform_driver cdns3_driver = {
        .probe          = cdns3_probe,
        .remove         = cdns3_remove,
        .driver         = {
                .name   = "cdns-usb3",
                .of_match_table = of_match_ptr(of_cdns3_match),
                .pm     = &cdns3_pm_ops,
        },
};

module_platform_driver(cdns3_driver);

MODULE_ALIAS("platform:cdns3");
MODULE_AUTHOR("Pawel Laszczak <pawell@cadence.com>");
MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("Cadence USB3 DRD Controller Driver");