/*
 * platform.c - DesignWare HS OTG Controller platform driver
 *
 * Copyright (C) Matthijs Kooijman <matthijs@stdin.nl>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions, and the following disclaimer,
 *    without modification.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The names of the above-listed copyright holders may not be used
 *    to endorse or promote products derived from this software without
 *    specific prior written permission.
 *
 * ALTERNATIVELY, this software may be distributed under the terms of the
 * GNU General Public License ("GPL") as published by the Free Software
 * Foundation; either version 2 of the License, or (at your option) any
 * later version.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/clk.h>
#include <linux/device.h>
#include <linux/dma-mapping.h>
#include <linux/of_device.h>
#include <linux/mutex.h>
#include <linux/platform_device.h>
#include <linux/phy/phy.h>
#include <linux/platform_data/s3c-hsotg.h>
#include <linux/reset.h>

#include <linux/usb/of.h>

#include "core.h"
#include "hcd.h"
#include "debug.h"

static const char dwc2_driver_name[] = "dwc2";

/*
 * Check the dr_mode against the module configuration and hardware
 * capabilities.
 *
 * The hardware, module, and dr_mode, can each be set to host, device,
 * or otg. Check that all these values are compatible and adjust the
 * value of dr_mode if possible.
 *
 *                      actual
 *    HW  MOD dr_mode   dr_mode
 *  ------------------------------
 *   HST  HST  any    :  HST
 *   HST  DEV  any    :  ---
 *   HST  OTG  any    :  HST
 *
 *   DEV  HST  any    :  ---
 *   DEV  DEV  any    :  DEV
 *   DEV  OTG  any    :  DEV
 *
 *   OTG  HST  any    :  HST
 *   OTG  DEV  any    :  DEV
 *   OTG  OTG  any    :  dr_mode
 */
static int dwc2_get_dr_mode(struct dwc2_hsotg *hsotg)
{
        enum usb_dr_mode mode;

        hsotg->dr_mode = usb_get_dr_mode(hsotg->dev);
        if (hsotg->dr_mode == USB_DR_MODE_UNKNOWN)
                hsotg->dr_mode = USB_DR_MODE_OTG;

        mode = hsotg->dr_mode;

        if (dwc2_hw_is_device(hsotg)) {
                if (IS_ENABLED(CONFIG_USB_DWC2_HOST)) {
                        dev_err(hsotg->dev,
                                "Controller does not support host mode.\n");
                        return -EINVAL;
                }
                mode = USB_DR_MODE_PERIPHERAL;
        } else if (dwc2_hw_is_host(hsotg)) {
                if (IS_ENABLED(CONFIG_USB_DWC2_PERIPHERAL)) {
                        dev_err(hsotg->dev,
                                "Controller does not support device mode.\n");
                        return -EINVAL;
                }
                mode = USB_DR_MODE_HOST;
        } else {
                if (IS_ENABLED(CONFIG_USB_DWC2_HOST))
                        mode = USB_DR_MODE_HOST;
                else if (IS_ENABLED(CONFIG_USB_DWC2_PERIPHERAL))
                        mode = USB_DR_MODE_PERIPHERAL;
        }

        if (mode != hsotg->dr_mode) {
                dev_warn(hsotg->dev,
                         "Configuration mismatch. dr_mode forced to %s\n",
                        mode == USB_DR_MODE_HOST ? "host" : "device");

                hsotg->dr_mode = mode;
        }

        return 0;
}

static int __dwc2_lowlevel_hw_enable(struct dwc2_hsotg *hsotg)
{
        struct platform_device *pdev = to_platform_device(hsotg->dev);
        int ret;

        ret = regulator_bulk_enable(ARRAY_SIZE(hsotg->supplies),
                                    hsotg->supplies);
        if (ret)
                return ret;

        if (hsotg->clk) {
                ret = clk_prepare_enable(hsotg->clk);
                if (ret)
                        return ret;
        }

        if (hsotg->uphy) {
                ret = usb_phy_init(hsotg->uphy);
        } else if (hsotg->plat && hsotg->plat->phy_init) {
                ret = hsotg->plat->phy_init(pdev, hsotg->plat->phy_type);
        } else {
                ret = phy_power_on(hsotg->phy);
                if (ret == 0)
                        ret = phy_init(hsotg->phy);
        }

        return ret;
}

/**
 * dwc2_lowlevel_hw_enable - enable platform lowlevel hw resources
 * @hsotg: The driver state
 *
 * A wrapper for platform code responsible for controlling
 * low-level USB platform resources (phy, clock, regulators)
 */
int dwc2_lowlevel_hw_enable(struct dwc2_hsotg *hsotg)
{
        int ret = __dwc2_lowlevel_hw_enable(hsotg);

        if (ret == 0)
                hsotg->ll_hw_enabled = true;
        return ret;
}

static int __dwc2_lowlevel_hw_disable(struct dwc2_hsotg *hsotg)
{
        struct platform_device *pdev = to_platform_device(hsotg->dev);
        int ret = 0;

        if (hsotg->uphy) {
                usb_phy_shutdown(hsotg->uphy);
        } else if (hsotg->plat && hsotg->plat->phy_exit) {
                ret = hsotg->plat->phy_exit(pdev, hsotg->plat->phy_type);
        } else {
                ret = phy_exit(hsotg->phy);
                if (ret == 0)
                        ret = phy_power_off(hsotg->phy);
        }
        if (ret)
                return ret;

        if (hsotg->clk)
                clk_disable_unprepare(hsotg->clk);

        ret = regulator_bulk_disable(ARRAY_SIZE(hsotg->supplies),
                                     hsotg->supplies);

        return ret;
}

/**
 * dwc2_lowlevel_hw_disable - disable platform lowlevel hw resources
 * @hsotg: The driver state
 *
 * A wrapper for platform code responsible for controlling
 * low-level USB platform resources (phy, clock, regulators)
 */
int dwc2_lowlevel_hw_disable(struct dwc2_hsotg *hsotg)
{
        int ret = __dwc2_lowlevel_hw_disable(hsotg);

        if (ret == 0)
                hsotg->ll_hw_enabled = false;
        return ret;
}

static int dwc2_lowlevel_hw_init(struct dwc2_hsotg *hsotg)
{
        int i, ret;

        hsotg->reset = devm_reset_control_get_optional(hsotg->dev, "dwc2");
        if (IS_ERR(hsotg->reset)) {
                ret = PTR_ERR(hsotg->reset);
                dev_err(hsotg->dev, "error getting reset control %d\n", ret);
                return ret;
        }

        reset_control_deassert(hsotg->reset);

        /* Set default UTMI width */
        hsotg->phyif = GUSBCFG_PHYIF16;

        /*
         * Attempt to find a generic PHY, then look for an old style
         * USB PHY and then fall back to pdata
         */
        hsotg->phy = devm_phy_get(hsotg->dev, "usb2-phy");
        if (IS_ERR(hsotg->phy)) {
                ret = PTR_ERR(hsotg->phy);
                switch (ret) {
                case -ENODEV:
                case -ENOSYS:
                        hsotg->phy = NULL;
                        break;
                case -EPROBE_DEFER:
                        return ret;
                default:
                        dev_err(hsotg->dev, "error getting phy %d\n", ret);
                        return ret;
                }
        }

        if (!hsotg->phy) {
                hsotg->uphy = devm_usb_get_phy(hsotg->dev, USB_PHY_TYPE_USB2);
                if (IS_ERR(hsotg->uphy)) {
                        ret = PTR_ERR(hsotg->uphy);
                        switch (ret) {
                        case -ENODEV:
                        case -ENXIO:
                                hsotg->uphy = NULL;
                                break;
                        case -EPROBE_DEFER:
                                return ret;
                        default:
                                dev_err(hsotg->dev, "error getting usb phy %d\n",
                                        ret);
                                return ret;
                        }
                }
        }

        hsotg->plat = dev_get_platdata(hsotg->dev);

        if (hsotg->phy) {
                /*
                 * If using the generic PHY framework, check if the PHY bus
                 * width is 8-bit and set the phyif appropriately.
                 */
                if (phy_get_bus_width(hsotg->phy) == 8)
                        hsotg->phyif = GUSBCFG_PHYIF8;
        }

        /* Clock */
        hsotg->clk = devm_clk_get(hsotg->dev, "otg");
        if (IS_ERR(hsotg->clk)) {
                hsotg->clk = NULL;
                dev_dbg(hsotg->dev, "cannot get otg clock\n");
        }

        /* Regulators */
        for (i = 0; i < ARRAY_SIZE(hsotg->supplies); i++)
                hsotg->supplies[i].supply = dwc2_hsotg_supply_names[i];

        ret = devm_regulator_bulk_get(hsotg->dev, ARRAY_SIZE(hsotg->supplies),
                                      hsotg->supplies);
        if (ret) {
                dev_err(hsotg->dev, "failed to request supplies: %d\n", ret);
                return ret;
        }
        return 0;
}

/**
 * dwc2_driver_remove() - Called when the DWC_otg core is unregistered with the
 * DWC_otg driver
 *
 * @dev: Platform device
 *
 * This routine is called, for example, when the rmmod command is executed. The
 * device may or may not be electrically present. If it is present, the driver
 * stops device processing. Any resources used on behalf of this device are
 * freed.
 */
static int dwc2_driver_remove(struct platform_device *dev)
{
        struct dwc2_hsotg *hsotg = platform_get_drvdata(dev);

        dwc2_debugfs_exit(hsotg);
        if (hsotg->hcd_enabled)
                dwc2_hcd_remove(hsotg);
        if (hsotg->gadget_enabled)
                dwc2_hsotg_remove(hsotg);

        if (hsotg->ll_hw_enabled)
                dwc2_lowlevel_hw_disable(hsotg);

        reset_control_assert(hsotg->reset);

        return 0;
}

/**
 * dwc2_driver_shutdown() - Called on device shutdown
 *
 * @dev: Platform device
 *
 * In specific conditions (involving usb hubs) dwc2 devices can create a
 * lot of interrupts, even to the point of overwhelming devices running
 * at low frequencies. Some devices need to do special clock handling
 * at shutdown-time which may bring the system clock below the threshold
 * of being able to handle the dwc2 interrupts. Disabling dwc2-irqs
 * prevents reboots/poweroffs from getting stuck in such cases.
 */
static void dwc2_driver_shutdown(struct platform_device *dev)
{
        struct dwc2_hsotg *hsotg = platform_get_drvdata(dev);

        disable_irq(hsotg->irq);
}

/**
 * dwc2_driver_probe() - Called when the DWC_otg core is bound to the DWC_otg
 * driver
 *
 * @dev: Platform device
 *
 * This routine creates the driver components required to control the device
 * (core, HCD, and PCD) and initializes the device. The driver components are
 * stored in a dwc2_hsotg structure. A reference to the dwc2_hsotg is saved
 * in the device private data. This allows the driver to access the dwc2_hsotg
 * structure on subsequent calls to driver methods for this device.
 */
static int dwc2_driver_probe(struct platform_device *dev)
{
        struct dwc2_hsotg *hsotg;
        struct resource *res;
        int retval;

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

        hsotg->dev = &dev->dev;

        /*
         * Use reasonable defaults so platforms don't have to provide these.
         */
        if (!dev->dev.dma_mask)
                dev->dev.dma_mask = &dev->dev.coherent_dma_mask;
        retval = dma_set_coherent_mask(&dev->dev, DMA_BIT_MASK(32));
        if (retval)
                return retval;

        res = platform_get_resource(dev, IORESOURCE_MEM, 0);
        hsotg->regs = devm_ioremap_resource(&dev->dev, res);
        if (IS_ERR(hsotg->regs))
                return PTR_ERR(hsotg->regs);

        dev_dbg(&dev->dev, "mapped PA %08lx to VA %p\n",
                (unsigned long)res->start, hsotg->regs);

        retval = dwc2_lowlevel_hw_init(hsotg);
        if (retval)
                return retval;

        spin_lock_init(&hsotg->lock);

        hsotg->irq = platform_get_irq(dev, 0);
        if (hsotg->irq < 0) {
                dev_err(&dev->dev, "missing IRQ resource\n");
                return hsotg->irq;
        }

        dev_dbg(hsotg->dev, "registering common handler for irq%d\n",
                hsotg->irq);
        retval = devm_request_irq(hsotg->dev, hsotg->irq,
                                  dwc2_handle_common_intr, IRQF_SHARED,
                                  dev_name(hsotg->dev), hsotg);
        if (retval)
                return retval;

        retval = dwc2_lowlevel_hw_enable(hsotg);
        if (retval)
                return retval;

        retval = dwc2_get_dr_mode(hsotg);
        if (retval)
                goto error;

        /*
         * Reset before dwc2_get_hwparams() then it could get power-on real
         * reset value form registers.
         */
        dwc2_core_reset_and_force_dr_mode(hsotg);

        /* Detect config values from hardware */
        retval = dwc2_get_hwparams(hsotg);
        if (retval)
                goto error;

        dwc2_force_dr_mode(hsotg);

        retval = dwc2_init_params(hsotg);
        if (retval)
                goto error;

        if (hsotg->dr_mode != USB_DR_MODE_HOST) {
                retval = dwc2_gadget_init(hsotg, hsotg->irq);
                if (retval)
                        goto error;
                hsotg->gadget_enabled = 1;
        }

        if (hsotg->dr_mode != USB_DR_MODE_PERIPHERAL) {
                retval = dwc2_hcd_init(hsotg);
                if (retval) {
                        if (hsotg->gadget_enabled)
                                dwc2_hsotg_remove(hsotg);
                        goto error;
                }
                hsotg->hcd_enabled = 1;
        }

        platform_set_drvdata(dev, hsotg);

        dwc2_debugfs_init(hsotg);

        /* Gadget code manages lowlevel hw on its own */
        if (hsotg->dr_mode == USB_DR_MODE_PERIPHERAL)
                dwc2_lowlevel_hw_disable(hsotg);

        return 0;

error:
        dwc2_lowlevel_hw_disable(hsotg);
        return retval;
}

static int __maybe_unused dwc2_suspend(struct device *dev)
{
        struct dwc2_hsotg *dwc2 = dev_get_drvdata(dev);
        int ret = 0;

        if (dwc2_is_device_mode(dwc2))
                dwc2_hsotg_suspend(dwc2);

        if (dwc2->ll_hw_enabled)
                ret = __dwc2_lowlevel_hw_disable(dwc2);

        return ret;
}

static int __maybe_unused dwc2_resume(struct device *dev)
{
        struct dwc2_hsotg *dwc2 = dev_get_drvdata(dev);
        int ret = 0;

        if (dwc2->ll_hw_enabled) {
                ret = __dwc2_lowlevel_hw_enable(dwc2);
                if (ret)
                        return ret;
        }

        if (dwc2_is_device_mode(dwc2))
                ret = dwc2_hsotg_resume(dwc2);

        return ret;
}

static const struct dev_pm_ops dwc2_dev_pm_ops = {
        SET_SYSTEM_SLEEP_PM_OPS(dwc2_suspend, dwc2_resume)
};

static struct platform_driver dwc2_platform_driver = {
        .driver = {
                .name = dwc2_driver_name,
                .of_match_table = dwc2_of_match_table,
                .pm = &dwc2_dev_pm_ops,
        },
        .probe = dwc2_driver_probe,
        .remove = dwc2_driver_remove,
        .shutdown = dwc2_driver_shutdown,
};

module_platform_driver(dwc2_platform_driver);

MODULE_DESCRIPTION("DESIGNWARE HS OTG Platform Glue");
MODULE_AUTHOR("Matthijs Kooijman <matthijs@stdin.nl>");
MODULE_LICENSE("Dual BSD/GPL");