// SPDX-License-Identifier: GPL-2.0
/*
 * USB Serial Converter Bus specific functions
 *
 * Copyright (C) 2002 Greg Kroah-Hartman (greg@kroah.com)
 */

#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/tty.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/usb.h>
#include <linux/usb/serial.h>

static int usb_serial_device_match(struct device *dev,
                                                struct device_driver *drv)
{
        struct usb_serial_driver *driver;
        const struct usb_serial_port *port;

        /*
         * drivers are already assigned to ports in serial_probe so it's
         * a simple check here.
         */
        port = to_usb_serial_port(dev);
        if (!port)
                return 0;

        driver = to_usb_serial_driver(drv);

        if (driver == port->serial->type)
                return 1;

        return 0;
}

static int usb_serial_device_probe(struct device *dev)
{
        struct usb_serial_driver *driver;
        struct usb_serial_port *port;
        struct device *tty_dev;
        int retval = 0;
        int minor;

        port = to_usb_serial_port(dev);
        if (!port)
                return -ENODEV;

        /* make sure suspend/resume doesn't race against port_probe */
        retval = usb_autopm_get_interface(port->serial->interface);
        if (retval)
                return retval;

        driver = port->serial->type;
        if (driver->port_probe) {
                retval = driver->port_probe(port);
                if (retval)
                        goto err_autopm_put;
        }

        minor = port->minor;
        tty_dev = tty_register_device(usb_serial_tty_driver, minor, dev);
        if (IS_ERR(tty_dev)) {
                retval = PTR_ERR(tty_dev);
                goto err_port_remove;
        }

        usb_autopm_put_interface(port->serial->interface);

        dev_info(&port->serial->dev->dev,
                 "%s converter now attached to ttyUSB%d\n",
                 driver->description, minor);

        return 0;

err_port_remove:
        if (driver->port_remove)
                driver->port_remove(port);
err_autopm_put:
        usb_autopm_put_interface(port->serial->interface);

        return retval;
}

static int usb_serial_device_remove(struct device *dev)
{
        struct usb_serial_driver *driver;
        struct usb_serial_port *port;
        int retval = 0;
        int minor;
        int autopm_err;

        port = to_usb_serial_port(dev);
        if (!port)
                return -ENODEV;

        /*
         * Make sure suspend/resume doesn't race against port_remove.
         *
         * Note that no further runtime PM callbacks will be made if
         * autopm_get fails.
         */
        autopm_err = usb_autopm_get_interface(port->serial->interface);

        minor = port->minor;
        tty_unregister_device(usb_serial_tty_driver, minor);

        driver = port->serial->type;
        if (driver->port_remove)
                retval = driver->port_remove(port);

        dev_info(dev, "%s converter now disconnected from ttyUSB%d\n",
                 driver->description, minor);

        if (!autopm_err)
                usb_autopm_put_interface(port->serial->interface);

        return retval;
}

static ssize_t new_id_store(struct device_driver *driver,
                            const char *buf, size_t count)
{
        struct usb_serial_driver *usb_drv = to_usb_serial_driver(driver);
        ssize_t retval = usb_store_new_id(&usb_drv->dynids, usb_drv->id_table,
                                         driver, buf, count);

        if (retval >= 0 && usb_drv->usb_driver != NULL)
                retval = usb_store_new_id(&usb_drv->usb_driver->dynids,
                                          usb_drv->usb_driver->id_table,
                                          &usb_drv->usb_driver->drvwrap.driver,
                                          buf, count);
        return retval;
}

static ssize_t new_id_show(struct device_driver *driver, char *buf)
{
        struct usb_serial_driver *usb_drv = to_usb_serial_driver(driver);

        return usb_show_dynids(&usb_drv->dynids, buf);
}
static DRIVER_ATTR_RW(new_id);

static struct attribute *usb_serial_drv_attrs[] = {
        &driver_attr_new_id.attr,
        NULL,
};
ATTRIBUTE_GROUPS(usb_serial_drv);

static void free_dynids(struct usb_serial_driver *drv)
{
        struct usb_dynid *dynid, *n;

        spin_lock(&drv->dynids.lock);
        list_for_each_entry_safe(dynid, n, &drv->dynids.list, node) {
                list_del(&dynid->node);
                kfree(dynid);
        }
        spin_unlock(&drv->dynids.lock);
}

struct bus_type usb_serial_bus_type = {
        .name =         "usb-serial",
        .match =        usb_serial_device_match,
        .probe =        usb_serial_device_probe,
        .remove =       usb_serial_device_remove,
        .drv_groups =   usb_serial_drv_groups,
};

int usb_serial_bus_register(struct usb_serial_driver *driver)
{
        int retval;

        driver->driver.bus = &usb_serial_bus_type;
        spin_lock_init(&driver->dynids.lock);
        INIT_LIST_HEAD(&driver->dynids.list);

        retval = driver_register(&driver->driver);

        return retval;
}

void usb_serial_bus_deregister(struct usb_serial_driver *driver)
{
        free_dynids(driver);
        driver_unregister(&driver->driver);
}