/**
 * udc-core.c - Core UDC Framework
 *
 * Copyright (C) 2015 Texas Instruments Incorporated - http://www.ti.com
 *
 * Author: Felipe Balbi <balbi@ti.com>
 *
 * Taken from Linux Kernel v3.19-rc1 (drivers/usb/gadget/udc-core.c) and ported
 * to uboot.
 *
 * commit 02e8c96627 : usb: gadget: udc: core: prepend udc_attach_driver with
 *                     usb_
 *
 * SPDX-License-Identifier:     GPL-2.0
 */

#include <linux/compat.h>
#include <malloc.h>
#include <asm/cache.h>
#include <asm/dma-mapping.h>
#include <common.h>

#include <linux/usb/ch9.h>
#include <linux/usb/gadget.h>

/**
 * struct usb_udc - describes one usb device controller
 * @driver - the gadget driver pointer. For use by the class code
 * @dev - the child device to the actual controller
 * @gadget - the gadget. For use by the class code
 * @list - for use by the udc class driver
 *
 * This represents the internal data structure which is used by the UDC-class
 * to hold information about udc driver and gadget together.
 */
struct usb_udc {
        struct usb_gadget_driver        *driver;
        struct usb_gadget               *gadget;
        struct device                   dev;
        struct list_head                list;
};

static struct class *udc_class;
static LIST_HEAD(udc_list);
DEFINE_MUTEX(udc_lock);

/* ------------------------------------------------------------------------- */

int usb_gadget_map_request(struct usb_gadget *gadget,
                struct usb_request *req, int is_in)
{
        if (req->length == 0)
                return 0;

        req->dma = dma_map_single(req->buf, req->length,
                                  is_in ? DMA_TO_DEVICE : DMA_FROM_DEVICE);

        return 0;
}
EXPORT_SYMBOL_GPL(usb_gadget_map_request);

void usb_gadget_unmap_request(struct usb_gadget *gadget,
                struct usb_request *req, int is_in)
{
        if (req->length == 0)
                return;

        dma_unmap_single((void *)(uintptr_t)req->dma, req->length,
                         is_in ? DMA_TO_DEVICE : DMA_FROM_DEVICE);
}
EXPORT_SYMBOL_GPL(usb_gadget_unmap_request);

/* ------------------------------------------------------------------------- */

/**
 * usb_gadget_giveback_request - give the request back to the gadget layer
 * Context: in_interrupt()
 *
 * This is called by device controller drivers in order to return the
 * completed request back to the gadget layer.
 */
void usb_gadget_giveback_request(struct usb_ep *ep,
                struct usb_request *req)
{
        req->complete(ep, req);
}
EXPORT_SYMBOL_GPL(usb_gadget_giveback_request);

/* ------------------------------------------------------------------------- */

void usb_gadget_set_state(struct usb_gadget *gadget,
                enum usb_device_state state)
{
        gadget->state = state;
}
EXPORT_SYMBOL_GPL(usb_gadget_set_state);

/* ------------------------------------------------------------------------- */

/**
 * usb_gadget_udc_reset - notifies the udc core that bus reset occurs
 * @gadget: The gadget which bus reset occurs
 * @driver: The gadget driver we want to notify
 *
 * If the udc driver has bus reset handler, it needs to call this when the bus
 * reset occurs, it notifies the gadget driver that the bus reset occurs as
 * well as updates gadget state.
 */
void usb_gadget_udc_reset(struct usb_gadget *gadget,
                struct usb_gadget_driver *driver)
{
        driver->reset(gadget);
        usb_gadget_set_state(gadget, USB_STATE_DEFAULT);
}
EXPORT_SYMBOL_GPL(usb_gadget_udc_reset);

/**
 * usb_gadget_udc_start - tells usb device controller to start up
 * @udc: The UDC to be started
 *
 * This call is issued by the UDC Class driver when it's about
 * to register a gadget driver to the device controller, before
 * calling gadget driver's bind() method.
 *
 * It allows the controller to be powered off until strictly
 * necessary to have it powered on.
 *
 * Returns zero on success, else negative errno.
 */
static inline int usb_gadget_udc_start(struct usb_udc *udc)
{
        return udc->gadget->ops->udc_start(udc->gadget, udc->driver);
}

/**
 * usb_gadget_udc_stop - tells usb device controller we don't need it anymore
 * @gadget: The device we want to stop activity
 * @driver: The driver to unbind from @gadget
 *
 * This call is issued by the UDC Class driver after calling
 * gadget driver's unbind() method.
 *
 * The details are implementation specific, but it can go as
 * far as powering off UDC completely and disable its data
 * line pullups.
 */
static inline void usb_gadget_udc_stop(struct usb_udc *udc)
{
        udc->gadget->ops->udc_stop(udc->gadget);
}

/**
 * usb_udc_release - release the usb_udc struct
 * @dev: the dev member within usb_udc
 *
 * This is called by driver's core in order to free memory once the last
 * reference is released.
 */
static void usb_udc_release(struct device *dev)
{
        struct usb_udc *udc;

        udc = container_of(dev, struct usb_udc, dev);
        kfree(udc);
}

/**
 * usb_add_gadget_udc_release - adds a new gadget to the udc class driver list
 * @parent: the parent device to this udc. Usually the controller driver's
 * device.
 * @gadget: the gadget to be added to the list.
 * @release: a gadget release function.
 *
 * Returns zero on success, negative errno otherwise.
 */
int usb_add_gadget_udc_release(struct device *parent, struct usb_gadget *gadget,
                void (*release)(struct device *dev))
{
        struct usb_udc          *udc;
        int                     ret = -ENOMEM;

        udc = kzalloc(sizeof(*udc), GFP_KERNEL);
        if (!udc)
                goto err1;

        dev_set_name(&gadget->dev, "gadget");
        gadget->dev.parent = parent;

        udc->dev.release = usb_udc_release;
        udc->dev.class = udc_class;
        udc->dev.parent = parent;

        udc->gadget = gadget;

        mutex_lock(&udc_lock);
        list_add_tail(&udc->list, &udc_list);

        usb_gadget_set_state(gadget, USB_STATE_NOTATTACHED);

        mutex_unlock(&udc_lock);

        return 0;

err1:
        return ret;
}
EXPORT_SYMBOL_GPL(usb_add_gadget_udc_release);

/**
 * usb_add_gadget_udc - adds a new gadget to the udc class driver list
 * @parent: the parent device to this udc. Usually the controller
 * driver's device.
 * @gadget: the gadget to be added to the list
 *
 * Returns zero on success, negative errno otherwise.
 */
int usb_add_gadget_udc(struct device *parent, struct usb_gadget *gadget)
{
        return usb_add_gadget_udc_release(parent, gadget, NULL);
}
EXPORT_SYMBOL_GPL(usb_add_gadget_udc);

static void usb_gadget_remove_driver(struct usb_udc *udc)
{
        dev_dbg(&udc->dev, "unregistering UDC driver [%s]\n",
                        udc->driver->function);

        usb_gadget_disconnect(udc->gadget);
        udc->driver->disconnect(udc->gadget);
        udc->driver->unbind(udc->gadget);
        usb_gadget_udc_stop(udc);

        udc->driver = NULL;
}

/**
 * usb_del_gadget_udc - deletes @udc from udc_list
 * @gadget: the gadget to be removed.
 *
 * This, will call usb_gadget_unregister_driver() if
 * the @udc is still busy.
 */
void usb_del_gadget_udc(struct usb_gadget *gadget)
{
        struct usb_udc          *udc = NULL;

        mutex_lock(&udc_lock);
        list_for_each_entry(udc, &udc_list, list)
                if (udc->gadget == gadget)
                        goto found;

        dev_err(gadget->dev.parent, "gadget not registered.\n");
        mutex_unlock(&udc_lock);

        return;

found:
        dev_vdbg(gadget->dev.parent, "unregistering gadget\n");

        list_del(&udc->list);
        mutex_unlock(&udc_lock);

        if (udc->driver)
                usb_gadget_remove_driver(udc);
}
EXPORT_SYMBOL_GPL(usb_del_gadget_udc);

/* ------------------------------------------------------------------------- */

static int udc_bind_to_driver(struct usb_udc *udc, struct usb_gadget_driver *driver)
{
        int ret;

        dev_dbg(&udc->dev, "registering UDC driver [%s]\n",
                        driver->function);

        udc->driver = driver;

        ret = driver->bind(udc->gadget);
        if (ret)
                goto err1;
        ret = usb_gadget_udc_start(udc);
        if (ret) {
                driver->unbind(udc->gadget);
                goto err1;
        }
        usb_gadget_connect(udc->gadget);

        return 0;
err1:
        if (ret != -EISNAM)
                dev_err(&udc->dev, "failed to start %s: %d\n",
                        udc->driver->function, ret);
        udc->driver = NULL;
        return ret;
}

int usb_gadget_probe_driver(struct usb_gadget_driver *driver)
{
        struct usb_udc          *udc = NULL;
        int                     ret;

        if (!driver || !driver->bind || !driver->setup)
                return -EINVAL;

        mutex_lock(&udc_lock);
        list_for_each_entry(udc, &udc_list, list) {
                /* For now we take the first one */
                if (!udc->driver)
                        goto found;
        }

        printf("couldn't find an available UDC\n");
        mutex_unlock(&udc_lock);
        return -ENODEV;
found:
        ret = udc_bind_to_driver(udc, driver);
        mutex_unlock(&udc_lock);
        return ret;
}
EXPORT_SYMBOL_GPL(usb_gadget_probe_driver);

int usb_gadget_register_driver(struct usb_gadget_driver *driver)
{
        return usb_gadget_probe_driver(driver);
}
EXPORT_SYMBOL_GPL(usb_gadget_register_driver);

int usb_gadget_unregister_driver(struct usb_gadget_driver *driver)
{
        struct usb_udc          *udc = NULL;
        int                     ret = -ENODEV;

        if (!driver || !driver->unbind)
                return -EINVAL;

        mutex_lock(&udc_lock);
        list_for_each_entry(udc, &udc_list, list)
                if (udc->driver == driver) {
                        usb_gadget_remove_driver(udc);
                        usb_gadget_set_state(udc->gadget,
                                        USB_STATE_NOTATTACHED);
                        ret = 0;
                        break;
                }

        mutex_unlock(&udc_lock);
        return ret;
}
EXPORT_SYMBOL_GPL(usb_gadget_unregister_driver);

MODULE_DESCRIPTION("UDC Framework");
MODULE_AUTHOR("Felipe Balbi <balbi@ti.com>");
MODULE_LICENSE("GPL v2");