// SPDX-License-Identifier: GPL-2.0+
/*
 * cdc-acm.c
 *
 * Copyright (c) 1999 Armin Fuerst      <fuerst@in.tum.de>
 * Copyright (c) 1999 Pavel Machek      <pavel@ucw.cz>
 * Copyright (c) 1999 Johannes Erdfelt  <johannes@erdfelt.com>
 * Copyright (c) 2000 Vojtech Pavlik    <vojtech@suse.cz>
 * Copyright (c) 2004 Oliver Neukum     <oliver@neukum.name>
 * Copyright (c) 2005 David Kubicek     <dave@awk.cz>
 * Copyright (c) 2011 Johan Hovold      <jhovold@gmail.com>
 *
 * USB Abstract Control Model driver for USB modems and ISDN adapters
 *
 * Sponsored by SuSE
 */

#undef DEBUG
#undef VERBOSE_DEBUG

#include <linux/kernel.h>
#include <linux/sched/signal.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/log2.h>
#include <linux/tty.h>
#include <linux/serial.h>
#include <linux/tty_driver.h>
#include <linux/tty_flip.h>
#include <linux/tty_ldisc.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/uaccess.h>
#include <linux/usb.h>
#include <linux/usb/cdc.h>
#include <asm/byteorder.h>
#include <linux/unaligned.h>
#include <linux/idr.h>
#include <linux/list.h>

#include "cdc-acm.h"


#define DRIVER_AUTHOR "Armin Fuerst, Pavel Machek, Johannes Erdfelt, Vojtech Pavlik, David Kubicek, Johan Hovold"
#define DRIVER_DESC "USB Abstract Control Model driver for USB modems and ISDN adapters"

static struct usb_driver acm_driver;
static struct tty_driver *acm_tty_driver;

static DEFINE_IDR(acm_minors);
static DEFINE_MUTEX(acm_minors_lock);

static void acm_tty_set_termios(struct tty_struct *tty,
                                const struct ktermios *termios_old);

/*
 * acm_minors accessors
 */

/*
 * Look up an ACM structure by minor. If found and not disconnected, increment
 * its refcount and return it with its mutex held.
 */
static struct acm *acm_get_by_minor(unsigned int minor)
{
        struct acm *acm;

        mutex_lock(&acm_minors_lock);
        acm = idr_find(&acm_minors, minor);
        if (acm) {
                mutex_lock(&acm->mutex);
                if (acm->disconnected) {
                        mutex_unlock(&acm->mutex);
                        acm = NULL;
                } else {
                        tty_port_get(&acm->port);
                        mutex_unlock(&acm->mutex);
                }
        }
        mutex_unlock(&acm_minors_lock);
        return acm;
}

/*
 * Try to find an available minor number and if found, associate it with 'acm'.
 */
static int acm_alloc_minor(struct acm *acm)
{
        int minor;

        mutex_lock(&acm_minors_lock);
        minor = idr_alloc(&acm_minors, acm, 0, ACM_TTY_MINORS, GFP_KERNEL);
        mutex_unlock(&acm_minors_lock);

        return minor;
}

/* Release the minor number associated with 'acm'.  */
static void acm_release_minor(struct acm *acm)
{
        mutex_lock(&acm_minors_lock);
        idr_remove(&acm_minors, acm->minor);
        mutex_unlock(&acm_minors_lock);
}

/*
 * Functions for ACM control messages.
 */

static int acm_ctrl_msg(struct acm *acm, int request, int value,
                                                        void *buf, int len)
{
        int retval;

        retval = usb_autopm_get_interface(acm->control);
        if (retval)
                return retval;

        retval = usb_control_msg(acm->dev, usb_sndctrlpipe(acm->dev, 0),
                request, USB_RT_ACM, value,
                acm->control->altsetting[0].desc.bInterfaceNumber,
                buf, len, USB_CTRL_SET_TIMEOUT);

        dev_dbg(&acm->control->dev,
                "%s - rq 0x%02x, val %#x, len %#x, result %d\n",
                __func__, request, value, len, retval);

        usb_autopm_put_interface(acm->control);

        return retval < 0 ? retval : 0;
}

/* devices aren't required to support these requests.
 * the cdc acm descriptor tells whether they do...
 */
static inline int acm_set_control(struct acm *acm, int control)
{
        if (acm->quirks & QUIRK_CONTROL_LINE_STATE)
                return -EOPNOTSUPP;

        return acm_ctrl_msg(acm, USB_CDC_REQ_SET_CONTROL_LINE_STATE,
                        control, NULL, 0);
}

#define acm_set_line(acm, line) \
        acm_ctrl_msg(acm, USB_CDC_REQ_SET_LINE_CODING, 0, line, sizeof *(line))
#define acm_send_break(acm, ms) \
        acm_ctrl_msg(acm, USB_CDC_REQ_SEND_BREAK, ms, NULL, 0)

static void acm_poison_urbs(struct acm *acm)
{
        int i;

        usb_poison_urb(acm->ctrlurb);
        for (i = 0; i < ACM_NW; i++)
                usb_poison_urb(acm->wb[i].urb);
        for (i = 0; i < acm->rx_buflimit; i++)
                usb_poison_urb(acm->read_urbs[i]);
}

static void acm_unpoison_urbs(struct acm *acm)
{
        int i;

        for (i = 0; i < acm->rx_buflimit; i++)
                usb_unpoison_urb(acm->read_urbs[i]);
        for (i = 0; i < ACM_NW; i++)
                usb_unpoison_urb(acm->wb[i].urb);
        usb_unpoison_urb(acm->ctrlurb);
}


/*
 * Write buffer management.
 * All of these assume proper locks taken by the caller.
 */

static int acm_wb_alloc(struct acm *acm)
{
        int i, wbn;
        struct acm_wb *wb;

        wbn = 0;
        i = 0;
        for (;;) {
                wb = &acm->wb[wbn];
                if (!wb->use) {
                        wb->use = true;
                        wb->len = 0;
                        return wbn;
                }
                wbn = (wbn + 1) % ACM_NW;
                if (++i >= ACM_NW)
                        return -1;
        }
}

static int acm_wb_is_avail(struct acm *acm)
{
        int i, n;
        unsigned long flags;

        n = ACM_NW;
        spin_lock_irqsave(&acm->write_lock, flags);
        for (i = 0; i < ACM_NW; i++)
                if(acm->wb[i].use)
                        n--;
        spin_unlock_irqrestore(&acm->write_lock, flags);
        return n;
}

/*
 * Finish write. Caller must hold acm->write_lock
 */
static void acm_write_done(struct acm *acm, struct acm_wb *wb)
{
        wb->use = false;
        acm->transmitting--;
        usb_autopm_put_interface_async(acm->control);
}

/*
 * Poke write.
 *
 * the caller is responsible for locking
 */

static int acm_start_wb(struct acm *acm, struct acm_wb *wb)
{
        int rc;

        acm->transmitting++;

        wb->urb->transfer_buffer = wb->buf;
        wb->urb->transfer_dma = wb->dmah;
        wb->urb->transfer_buffer_length = wb->len;
        wb->urb->dev = acm->dev;

        rc = usb_submit_urb(wb->urb, GFP_ATOMIC);
        if (rc < 0) {
                if (rc != -EPERM)
                        dev_err(&acm->data->dev,
                                "%s - usb_submit_urb(write bulk) failed: %d\n",
                                __func__, rc);
                acm_write_done(acm, wb);
        }
        return rc;
}

/*
 * attributes exported through sysfs
 */
static ssize_t bmCapabilities_show
(struct device *dev, struct device_attribute *attr, char *buf)
{
        struct usb_interface *intf = to_usb_interface(dev);
        struct acm *acm = usb_get_intfdata(intf);

        return sprintf(buf, "%d", acm->ctrl_caps);
}
static DEVICE_ATTR_RO(bmCapabilities);

static ssize_t wCountryCodes_show
(struct device *dev, struct device_attribute *attr, char *buf)
{
        struct usb_interface *intf = to_usb_interface(dev);
        struct acm *acm = usb_get_intfdata(intf);

        memcpy(buf, acm->country_codes, acm->country_code_size);
        return acm->country_code_size;
}

static DEVICE_ATTR_RO(wCountryCodes);

static ssize_t iCountryCodeRelDate_show
(struct device *dev, struct device_attribute *attr, char *buf)
{
        struct usb_interface *intf = to_usb_interface(dev);
        struct acm *acm = usb_get_intfdata(intf);

        return sprintf(buf, "%d", acm->country_rel_date);
}

static DEVICE_ATTR_RO(iCountryCodeRelDate);
/*
 * Interrupt handlers for various ACM device responses
 */

static void acm_process_notification(struct acm *acm, unsigned char *buf)
{
        int newctrl;
        int difference;
        unsigned long flags;
        struct usb_cdc_notification *dr = (struct usb_cdc_notification *)buf;
        unsigned char *data = buf + sizeof(struct usb_cdc_notification);

        switch (dr->bNotificationType) {
        case USB_CDC_NOTIFY_NETWORK_CONNECTION:
                dev_dbg(&acm->control->dev,
                        "%s - network connection: %d\n", __func__, dr->wValue);
                break;

        case USB_CDC_NOTIFY_SERIAL_STATE:
                if (le16_to_cpu(dr->wLength) != 2) {
                        dev_dbg(&acm->control->dev,
                                "%s - malformed serial state\n", __func__);
                        break;
                }

                newctrl = get_unaligned_le16(data);
                dev_dbg(&acm->control->dev,
                        "%s - serial state: 0x%x\n", __func__, newctrl);

                if (!acm->clocal && (acm->ctrlin & ~newctrl & USB_CDC_SERIAL_STATE_DCD)) {
                        dev_dbg(&acm->control->dev,
                                "%s - calling hangup\n", __func__);
                        tty_port_tty_hangup(&acm->port, false);
                }

                difference = acm->ctrlin ^ newctrl;

                if ((difference & USB_CDC_SERIAL_STATE_DCD) && acm->port.tty) {
                        struct tty_ldisc *ld = tty_ldisc_ref(acm->port.tty);
                        if (ld) {
                                if (ld->ops->dcd_change)
                                        ld->ops->dcd_change(acm->port.tty, newctrl & USB_CDC_SERIAL_STATE_DCD);
                                tty_ldisc_deref(ld);
                        }
                }

                spin_lock_irqsave(&acm->read_lock, flags);
                acm->ctrlin = newctrl;
                acm->oldcount = acm->iocount;

                if (difference & USB_CDC_SERIAL_STATE_DSR)
                        acm->iocount.dsr++;
                if (difference & USB_CDC_SERIAL_STATE_DCD)
                        acm->iocount.dcd++;
                if (newctrl & USB_CDC_SERIAL_STATE_BREAK) {
                        acm->iocount.brk++;
                        tty_insert_flip_char(&acm->port, 0, TTY_BREAK);
                }
                if (newctrl & USB_CDC_SERIAL_STATE_RING_SIGNAL)
                        acm->iocount.rng++;
                if (newctrl & USB_CDC_SERIAL_STATE_FRAMING)
                        acm->iocount.frame++;
                if (newctrl & USB_CDC_SERIAL_STATE_PARITY)
                        acm->iocount.parity++;
                if (newctrl & USB_CDC_SERIAL_STATE_OVERRUN)
                        acm->iocount.overrun++;
                spin_unlock_irqrestore(&acm->read_lock, flags);

                if (newctrl & USB_CDC_SERIAL_STATE_BREAK)
                        tty_flip_buffer_push(&acm->port);

                if (difference)
                        wake_up_all(&acm->wioctl);

                break;

        default:
                dev_dbg(&acm->control->dev,
                        "%s - unknown notification %d received: index %d len %d\n",
                        __func__,
                        dr->bNotificationType, dr->wIndex, dr->wLength);
        }
}

/* control interface reports status changes with "interrupt" transfers */
static void acm_ctrl_irq(struct urb *urb)
{
        struct acm *acm = urb->context;
        struct usb_cdc_notification *dr;
        unsigned int current_size = urb->actual_length;
        unsigned int expected_size, copy_size, alloc_size;
        int retval;
        int status = urb->status;

        switch (status) {
        case 0:
                /* success */
                break;
        case -ECONNRESET:
        case -ENOENT:
        case -ESHUTDOWN:
                /* this urb is terminated, clean up */
                dev_dbg(&acm->control->dev,
                        "%s - urb shutting down with status: %d\n",
                        __func__, status);
                return;
        default:
                dev_dbg(&acm->control->dev,
                        "%s - nonzero urb status received: %d\n",
                        __func__, status);
                goto exit;
        }

        usb_mark_last_busy(acm->dev);

        if (acm->nb_index == 0) {
                /*
                 * The first chunk of a message must contain at least the
                 * notification header with the length field, otherwise we
                 * can't get an expected_size.
                 */
                if (current_size < sizeof(struct usb_cdc_notification)) {
                        dev_dbg(&acm->control->dev, "urb too short\n");
                        goto exit;
                }
                dr = urb->transfer_buffer;
        } else {
                dr = (struct usb_cdc_notification *)acm->notification_buffer;
        }
        /* size = notification-header + (optional) data */
        expected_size = sizeof(struct usb_cdc_notification) +
                                        le16_to_cpu(dr->wLength);

        if (acm->nb_index != 0 || current_size < expected_size) {
                /* notification is transmitted fragmented, reassemble */
                if (acm->nb_size < expected_size) {
                        u8 *new_buffer;
                        alloc_size = roundup_pow_of_two(expected_size);
                        /* Final freeing is done on disconnect. */
                        new_buffer = krealloc(acm->notification_buffer,
                                              alloc_size, GFP_ATOMIC);
                        if (!new_buffer) {
                                acm->nb_index = 0;
                                goto exit;
                        }

                        acm->notification_buffer = new_buffer;
                        acm->nb_size = alloc_size;
                        dr = (struct usb_cdc_notification *)acm->notification_buffer;
                }

                copy_size = min(current_size,
                                expected_size - acm->nb_index);

                memcpy(&acm->notification_buffer[acm->nb_index],
                       urb->transfer_buffer, copy_size);
                acm->nb_index += copy_size;
                current_size = acm->nb_index;
        }

        if (current_size >= expected_size) {
                /* notification complete */
                acm_process_notification(acm, (unsigned char *)dr);
                acm->nb_index = 0;
        }

exit:
        retval = usb_submit_urb(urb, GFP_ATOMIC);
        if (retval && retval != -EPERM && retval != -ENODEV)
                dev_err(&acm->control->dev,
                        "%s - usb_submit_urb failed: %d\n", __func__, retval);
        else
                dev_vdbg(&acm->control->dev,
                        "control resubmission terminated %d\n", retval);
}

static int acm_submit_read_urb(struct acm *acm, int index, gfp_t mem_flags)
{
        int res;

        if (!test_and_clear_bit(index, &acm->read_urbs_free))
                return 0;

        res = usb_submit_urb(acm->read_urbs[index], mem_flags);
        if (res) {
                if (res != -EPERM && res != -ENODEV) {
                        dev_err(&acm->data->dev,
                                "urb %d failed submission with %d\n",
                                index, res);
                } else {
                        dev_vdbg(&acm->data->dev, "intended failure %d\n", res);
                }
                set_bit(index, &acm->read_urbs_free);
                return res;
        } else {
                dev_vdbg(&acm->data->dev, "submitted urb %d\n", index);
        }

        return 0;
}

static int acm_submit_read_urbs(struct acm *acm, gfp_t mem_flags)
{
        int res;
        int i;

        for (i = 0; i < acm->rx_buflimit; ++i) {
                res = acm_submit_read_urb(acm, i, mem_flags);
                if (res)
                        return res;
        }

        return 0;
}

static void acm_process_read_urb(struct acm *acm, struct urb *urb)
{
        unsigned long flags;

        if (!urb->actual_length)
                return;

        spin_lock_irqsave(&acm->read_lock, flags);
        tty_insert_flip_string(&acm->port, urb->transfer_buffer,
                        urb->actual_length);
        spin_unlock_irqrestore(&acm->read_lock, flags);

        tty_flip_buffer_push(&acm->port);
}

static void acm_read_bulk_callback(struct urb *urb)
{
        struct acm_rb *rb = urb->context;
        struct acm *acm = rb->instance;
        int status = urb->status;
        bool stopped = false;
        bool stalled = false;
        bool cooldown = false;

        dev_vdbg(&acm->data->dev, "got urb %d, len %d, status %d\n",
                rb->index, urb->actual_length, status);

        switch (status) {
        case 0:
                usb_mark_last_busy(acm->dev);
                acm_process_read_urb(acm, urb);
                break;
        case -EPIPE:
                set_bit(EVENT_RX_STALL, &acm->flags);
                stalled = true;
                break;
        case -ENOENT:
        case -ECONNRESET:
        case -ESHUTDOWN:
                dev_dbg(&acm->data->dev,
                        "%s - urb shutting down with status: %d\n",
                        __func__, status);
                stopped = true;
                break;
        case -EOVERFLOW:
        case -EPROTO:
                dev_dbg(&acm->data->dev,
                        "%s - cooling babbling device\n", __func__);
                usb_mark_last_busy(acm->dev);
                set_bit(rb->index, &acm->urbs_in_error_delay);
                set_bit(ACM_ERROR_DELAY, &acm->flags);
                cooldown = true;
                break;
        default:
                dev_dbg(&acm->data->dev,
                        "%s - nonzero urb status received: %d\n",
                        __func__, status);
                break;
        }

        /*
         * Make sure URB processing is done before marking as free to avoid
         * racing with unthrottle() on another CPU. Matches the barriers
         * implied by the test_and_clear_bit() in acm_submit_read_urb().
         */
        smp_mb__before_atomic();
        set_bit(rb->index, &acm->read_urbs_free);
        /*
         * Make sure URB is marked as free before checking the throttled flag
         * to avoid racing with unthrottle() on another CPU. Matches the
         * smp_mb() in unthrottle().
         */
        smp_mb__after_atomic();

        if (stopped || stalled || cooldown) {
                if (stalled)
                        schedule_delayed_work(&acm->dwork, 0);
                else if (cooldown)
                        schedule_delayed_work(&acm->dwork, HZ / 2);
                return;
        }

        if (test_bit(ACM_THROTTLED, &acm->flags))
                return;

        acm_submit_read_urb(acm, rb->index, GFP_ATOMIC);
}

/* data interface wrote those outgoing bytes */
static void acm_write_bulk(struct urb *urb)
{
        struct acm_wb *wb = urb->context;
        struct acm *acm = wb->instance;
        unsigned long flags;
        int status = urb->status;

        if (status || (urb->actual_length != urb->transfer_buffer_length))
                dev_vdbg(&acm->data->dev, "wrote len %d/%d, status %d\n",
                        urb->actual_length,
                        urb->transfer_buffer_length,
                        status);

        spin_lock_irqsave(&acm->write_lock, flags);
        acm_write_done(acm, wb);
        spin_unlock_irqrestore(&acm->write_lock, flags);
        set_bit(EVENT_TTY_WAKEUP, &acm->flags);
        schedule_delayed_work(&acm->dwork, 0);
}

static void acm_softint(struct work_struct *work)
{
        int i;
        struct acm *acm = container_of(work, struct acm, dwork.work);

        if (test_bit(EVENT_RX_STALL, &acm->flags)) {
                smp_mb(); /* against acm_suspend() */
                if (!acm->susp_count) {
                        for (i = 0; i < acm->rx_buflimit; i++)
                                usb_kill_urb(acm->read_urbs[i]);
                        usb_clear_halt(acm->dev, acm->in);
                        acm_submit_read_urbs(acm, GFP_KERNEL);
                        clear_bit(EVENT_RX_STALL, &acm->flags);
                }
        }

        if (test_and_clear_bit(ACM_ERROR_DELAY, &acm->flags)) {
                for (i = 0; i < acm->rx_buflimit; i++)
                        if (test_and_clear_bit(i, &acm->urbs_in_error_delay))
                                acm_submit_read_urb(acm, i, GFP_KERNEL);
        }

        if (test_and_clear_bit(EVENT_TTY_WAKEUP, &acm->flags))
                tty_port_tty_wakeup(&acm->port);
}

/*
 * TTY handlers
 */

static int acm_tty_install(struct tty_driver *driver, struct tty_struct *tty)
{
        struct acm *acm;
        int retval;

        acm = acm_get_by_minor(tty->index);
        if (!acm)
                return -ENODEV;

        retval = tty_standard_install(driver, tty);
        if (retval)
                goto error_init_termios;

        /*
         * Suppress initial echoing for some devices which might send data
         * immediately after acm driver has been installed.
         */
        if (acm->quirks & DISABLE_ECHO)
                tty->termios.c_lflag &= ~ECHO;

        tty->driver_data = acm;

        return 0;

error_init_termios:
        tty_port_put(&acm->port);
        return retval;
}

static int acm_tty_open(struct tty_struct *tty, struct file *filp)
{
        struct acm *acm = tty->driver_data;

        return tty_port_open(&acm->port, tty, filp);
}

static void acm_port_dtr_rts(struct tty_port *port, bool active)
{
        struct acm *acm = container_of(port, struct acm, port);
        int val;
        int res;

        if (active)
                val = USB_CDC_CTRL_DTR | USB_CDC_CTRL_RTS;
        else
                val = 0;

        /* FIXME: add missing ctrlout locking throughout driver */
        acm->ctrlout = val;

        res = acm_set_control(acm, val);
        if (res && (acm->ctrl_caps & USB_CDC_CAP_LINE))
                /* This is broken in too many devices to spam the logs */
                dev_dbg(&acm->control->dev, "failed to set dtr/rts\n");
}

static int acm_port_activate(struct tty_port *port, struct tty_struct *tty)
{
        struct acm *acm = container_of(port, struct acm, port);
        int retval = -ENODEV;
        int i;

        mutex_lock(&acm->mutex);
        if (acm->disconnected)
                goto disconnected;

        retval = usb_autopm_get_interface(acm->control);
        if (retval)
                goto error_get_interface;

        set_bit(TTY_NO_WRITE_SPLIT, &tty->flags);
        acm->control->needs_remote_wakeup = 1;

        acm->ctrlurb->dev = acm->dev;
        retval = usb_submit_urb(acm->ctrlurb, GFP_KERNEL);
        if (retval) {
                dev_err(&acm->control->dev,
                        "%s - usb_submit_urb(ctrl irq) failed\n", __func__);
                goto error_submit_urb;
        }

        acm_tty_set_termios(tty, NULL);

        /*
         * Unthrottle device in case the TTY was closed while throttled.
         */
        clear_bit(ACM_THROTTLED, &acm->flags);

        retval = acm_submit_read_urbs(acm, GFP_KERNEL);
        if (retval)
                goto error_submit_read_urbs;

        usb_autopm_put_interface(acm->control);

        mutex_unlock(&acm->mutex);

        return 0;

error_submit_read_urbs:
        for (i = 0; i < acm->rx_buflimit; i++)
                usb_kill_urb(acm->read_urbs[i]);
        usb_kill_urb(acm->ctrlurb);
error_submit_urb:
        usb_autopm_put_interface(acm->control);
error_get_interface:
disconnected:
        mutex_unlock(&acm->mutex);

        return usb_translate_errors(retval);
}

static void acm_port_destruct(struct tty_port *port)
{
        struct acm *acm = container_of(port, struct acm, port);

        if (acm->minor != ACM_MINOR_INVALID)
                acm_release_minor(acm);
        usb_put_intf(acm->control);
        kfree(acm->country_codes);
        kfree(acm);
}

static void acm_port_shutdown(struct tty_port *port)
{
        struct acm *acm = container_of(port, struct acm, port);
        struct urb *urb;
        struct acm_wb *wb;

        /*
         * Need to grab write_lock to prevent race with resume, but no need to
         * hold it due to the tty-port initialised flag.
         */
        acm_poison_urbs(acm);
        spin_lock_irq(&acm->write_lock);
        spin_unlock_irq(&acm->write_lock);

        usb_autopm_get_interface_no_resume(acm->control);
        acm->control->needs_remote_wakeup = 0;
        usb_autopm_put_interface(acm->control);

        for (;;) {
                urb = usb_get_from_anchor(&acm->delayed);
                if (!urb)
                        break;
                wb = urb->context;
                wb->use = false;
                usb_autopm_put_interface_async(acm->control);
        }

        acm_unpoison_urbs(acm);

}

static void acm_tty_cleanup(struct tty_struct *tty)
{
        struct acm *acm = tty->driver_data;

        tty_port_put(&acm->port);
}

static void acm_tty_hangup(struct tty_struct *tty)
{
        struct acm *acm = tty->driver_data;

        tty_port_hangup(&acm->port);
}

static void acm_tty_close(struct tty_struct *tty, struct file *filp)
{
        struct acm *acm = tty->driver_data;

        tty_port_close(&acm->port, tty, filp);
}

static ssize_t acm_tty_write(struct tty_struct *tty, const u8 *buf,
                             size_t count)
{
        struct acm *acm = tty->driver_data;
        int stat;
        unsigned long flags;
        int wbn;
        struct acm_wb *wb;

        if (!count)
                return 0;

        dev_vdbg(&acm->data->dev, "%zu bytes from tty layer\n", count);

        spin_lock_irqsave(&acm->write_lock, flags);
        wbn = acm_wb_alloc(acm);
        if (wbn < 0) {
                spin_unlock_irqrestore(&acm->write_lock, flags);
                return 0;
        }
        wb = &acm->wb[wbn];

        if (!acm->dev) {
                wb->use = false;
                spin_unlock_irqrestore(&acm->write_lock, flags);
                return -ENODEV;
        }

        count = (count > acm->writesize) ? acm->writesize : count;
        dev_vdbg(&acm->data->dev, "writing %zu bytes\n", count);
        memcpy(wb->buf, buf, count);
        wb->len = count;

        stat = usb_autopm_get_interface_async(acm->control);
        if (stat) {
                wb->use = false;
                spin_unlock_irqrestore(&acm->write_lock, flags);
                return stat;
        }

        if (acm->susp_count) {
                usb_anchor_urb(wb->urb, &acm->delayed);
                spin_unlock_irqrestore(&acm->write_lock, flags);
                return count;
        }

        stat = acm_start_wb(acm, wb);
        spin_unlock_irqrestore(&acm->write_lock, flags);

        if (stat < 0)
                return stat;
        return count;
}

static unsigned int acm_tty_write_room(struct tty_struct *tty)
{
        struct acm *acm = tty->driver_data;
        /*
         * Do not let the line discipline to know that we have a reserve,
         * or it might get too enthusiastic.
         */
        return acm_wb_is_avail(acm) ? acm->writesize : 0;
}

static void acm_tty_flush_buffer(struct tty_struct *tty)
{
        struct acm *acm = tty->driver_data;
        unsigned long flags;
        int i;

        spin_lock_irqsave(&acm->write_lock, flags);
        for (i = 0; i < ACM_NW; i++)
                if (acm->wb[i].use)
                        usb_unlink_urb(acm->wb[i].urb);
        spin_unlock_irqrestore(&acm->write_lock, flags);
}

static unsigned int acm_tty_chars_in_buffer(struct tty_struct *tty)
{
        struct acm *acm = tty->driver_data;
        /*
         * if the device was unplugged then any remaining characters fell out
         * of the connector ;)
         */
        if (acm->disconnected)
                return 0;
        /*
         * This is inaccurate (overcounts), but it works.
         */
        return (ACM_NW - acm_wb_is_avail(acm)) * acm->writesize;
}

static void acm_tty_throttle(struct tty_struct *tty)
{
        struct acm *acm = tty->driver_data;

        set_bit(ACM_THROTTLED, &acm->flags);
}

static void acm_tty_unthrottle(struct tty_struct *tty)
{
        struct acm *acm = tty->driver_data;

        clear_bit(ACM_THROTTLED, &acm->flags);

        /* Matches the smp_mb__after_atomic() in acm_read_bulk_callback(). */
        smp_mb();

        acm_submit_read_urbs(acm, GFP_KERNEL);
}

static int acm_tty_break_ctl(struct tty_struct *tty, int state)
{
        struct acm *acm = tty->driver_data;
        int retval;

        if (!(acm->ctrl_caps & USB_CDC_CAP_BRK))
                return -EOPNOTSUPP;

        retval = acm_send_break(acm, state ? 0xffff : 0);
        if (retval < 0)
                dev_dbg(&acm->control->dev,
                        "%s - send break failed\n", __func__);
        return retval;
}

static int acm_tty_tiocmget(struct tty_struct *tty)
{
        struct acm *acm = tty->driver_data;

        return (acm->ctrlout & USB_CDC_CTRL_DTR ? TIOCM_DTR : 0) |
               (acm->ctrlout & USB_CDC_CTRL_RTS ? TIOCM_RTS : 0) |
               (acm->ctrlin  & USB_CDC_SERIAL_STATE_DSR ? TIOCM_DSR : 0) |
               (acm->ctrlin  & USB_CDC_SERIAL_STATE_RING_SIGNAL ? TIOCM_RI : 0) |
               (acm->ctrlin  & USB_CDC_SERIAL_STATE_DCD ? TIOCM_CD : 0) |
               TIOCM_CTS;
}

static int acm_tty_tiocmset(struct tty_struct *tty,
                            unsigned int set, unsigned int clear)
{
        struct acm *acm = tty->driver_data;
        unsigned int newctrl;

        newctrl = acm->ctrlout;
        set = (set & TIOCM_DTR ? USB_CDC_CTRL_DTR : 0) |
              (set & TIOCM_RTS ? USB_CDC_CTRL_RTS : 0);
        clear = (clear & TIOCM_DTR ? USB_CDC_CTRL_DTR : 0) |
                (clear & TIOCM_RTS ? USB_CDC_CTRL_RTS : 0);

        newctrl = (newctrl & ~clear) | set;

        if (acm->ctrlout == newctrl)
                return 0;
        return acm_set_control(acm, acm->ctrlout = newctrl);
}

static int get_serial_info(struct tty_struct *tty, struct serial_struct *ss)
{
        struct acm *acm = tty->driver_data;

        ss->line = acm->minor;
        mutex_lock(&acm->port.mutex);
        ss->close_delay = jiffies_to_msecs(acm->port.close_delay) / 10;
        ss->closing_wait = acm->port.closing_wait == ASYNC_CLOSING_WAIT_NONE ?
                                ASYNC_CLOSING_WAIT_NONE :
                                jiffies_to_msecs(acm->port.closing_wait) / 10;
        mutex_unlock(&acm->port.mutex);
        return 0;
}

static int set_serial_info(struct tty_struct *tty, struct serial_struct *ss)
{
        struct acm *acm = tty->driver_data;
        unsigned int closing_wait, close_delay;
        int retval = 0;

        close_delay = msecs_to_jiffies(ss->close_delay * 10);
        closing_wait = ss->closing_wait == ASYNC_CLOSING_WAIT_NONE ?
                        ASYNC_CLOSING_WAIT_NONE :
                        msecs_to_jiffies(ss->closing_wait * 10);

        mutex_lock(&acm->port.mutex);

        if (!capable(CAP_SYS_ADMIN)) {
                if ((close_delay != acm->port.close_delay) ||
                    (closing_wait != acm->port.closing_wait))
                        retval = -EPERM;
        } else {
                acm->port.close_delay  = close_delay;
                acm->port.closing_wait = closing_wait;
        }

        mutex_unlock(&acm->port.mutex);
        return retval;
}

static int wait_serial_change(struct acm *acm, unsigned long arg)
{
        int rv = 0;
        DECLARE_WAITQUEUE(wait, current);
        struct async_icount old, new;

        do {
                spin_lock_irq(&acm->read_lock);
                old = acm->oldcount;
                new = acm->iocount;
                acm->oldcount = new;
                spin_unlock_irq(&acm->read_lock);

                if ((arg & TIOCM_DSR) &&
                        old.dsr != new.dsr)
                        break;
                if ((arg & TIOCM_CD)  &&
                        old.dcd != new.dcd)
                        break;
                if ((arg & TIOCM_RI) &&
                        old.rng != new.rng)
                        break;

                add_wait_queue(&acm->wioctl, &wait);
                set_current_state(TASK_INTERRUPTIBLE);
                schedule();
                remove_wait_queue(&acm->wioctl, &wait);
                if (acm->disconnected) {
                        if (arg & TIOCM_CD)
                                break;
                        else
                                rv = -ENODEV;
                } else {
                        if (signal_pending(current))
                                rv = -ERESTARTSYS;
                }
        } while (!rv);

        

        return rv;
}

static int acm_tty_get_icount(struct tty_struct *tty,
                                        struct serial_icounter_struct *icount)
{
        struct acm *acm = tty->driver_data;

        icount->dsr = acm->iocount.dsr;
        icount->rng = acm->iocount.rng;
        icount->dcd = acm->iocount.dcd;
        icount->frame = acm->iocount.frame;
        icount->overrun = acm->iocount.overrun;
        icount->parity = acm->iocount.parity;
        icount->brk = acm->iocount.brk;

        return 0;
}

static int acm_tty_ioctl(struct tty_struct *tty,
                                        unsigned int cmd, unsigned long arg)
{
        struct acm *acm = tty->driver_data;
        int rv = -ENOIOCTLCMD;

        switch (cmd) {
        case TIOCMIWAIT:
                rv = usb_autopm_get_interface(acm->control);
                if (rv < 0) {
                        rv = -EIO;
                        break;
                }
                rv = wait_serial_change(acm, arg);
                usb_autopm_put_interface(acm->control);
                break;
        }

        return rv;
}

static void acm_tty_set_termios(struct tty_struct *tty,
                                const struct ktermios *termios_old)
{
        struct acm *acm = tty->driver_data;
        struct ktermios *termios = &tty->termios;
        struct usb_cdc_line_coding newline;
        int newctrl = acm->ctrlout;

        newline.dwDTERate = cpu_to_le32(tty_get_baud_rate(tty));
        newline.bCharFormat = termios->c_cflag & CSTOPB ? 2 : 0;
        newline.bParityType = termios->c_cflag & PARENB ?
                                (termios->c_cflag & PARODD ? 1 : 2) +
                                (termios->c_cflag & CMSPAR ? 2 : 0) : 0;
        newline.bDataBits = tty_get_char_size(termios->c_cflag);

        /* FIXME: Needs to clear unsupported bits in the termios */
        acm->clocal = ((termios->c_cflag & CLOCAL) != 0);

        if (C_BAUD(tty) == B0) {
                newline.dwDTERate = acm->line.dwDTERate;
                newctrl &= ~USB_CDC_CTRL_DTR;
        } else if (termios_old && (termios_old->c_cflag & CBAUD) == B0) {
                newctrl |=  USB_CDC_CTRL_DTR;
        }

        if (newctrl != acm->ctrlout)
                acm_set_control(acm, acm->ctrlout = newctrl);

        if (memcmp(&acm->line, &newline, sizeof newline)) {
                memcpy(&acm->line, &newline, sizeof newline);
                dev_dbg(&acm->control->dev, "%s - set line: %d %d %d %d\n",
                        __func__,
                        le32_to_cpu(newline.dwDTERate),
                        newline.bCharFormat, newline.bParityType,
                        newline.bDataBits);
                acm_set_line(acm, &acm->line);
        }
}

static const struct tty_port_operations acm_port_ops = {
        .dtr_rts = acm_port_dtr_rts,
        .shutdown = acm_port_shutdown,
        .activate = acm_port_activate,
        .destruct = acm_port_destruct,
};

/*
 * USB probe and disconnect routines.
 */

/* Little helpers: write/read buffers free */
static void acm_write_buffers_free(struct acm *acm)
{
        int i;
        struct acm_wb *wb;

        for (wb = &acm->wb[0], i = 0; i < ACM_NW; i++, wb++)
                usb_free_coherent(acm->dev, acm->writesize, wb->buf, wb->dmah);
}

static void acm_read_buffers_free(struct acm *acm)
{
        int i;

        for (i = 0; i < acm->rx_buflimit; i++)
                usb_free_coherent(acm->dev, acm->readsize,
                          acm->read_buffers[i].base, acm->read_buffers[i].dma);
}

/* Little helper: write buffers allocate */
static int acm_write_buffers_alloc(struct acm *acm)
{
        int i;
        struct acm_wb *wb;

        for (wb = &acm->wb[0], i = 0; i < ACM_NW; i++, wb++) {
                wb->buf = usb_alloc_coherent(acm->dev, acm->writesize, GFP_KERNEL,
                    &wb->dmah);
                if (!wb->buf) {
                        while (i != 0) {
                                --i;
                                --wb;
                                usb_free_coherent(acm->dev, acm->writesize,
                                    wb->buf, wb->dmah);
                        }
                        return -ENOMEM;
                }
        }
        return 0;
}

static int acm_probe(struct usb_interface *intf,
                     const struct usb_device_id *id)
{
        struct usb_cdc_union_desc *union_header = NULL;
        struct usb_cdc_call_mgmt_descriptor *cmgmd = NULL;
        unsigned char *buffer = intf->altsetting->extra;
        int buflen = intf->altsetting->extralen;
        struct usb_interface *control_interface;
        struct usb_interface *data_interface;
        struct usb_endpoint_descriptor *epctrl = NULL;
        struct usb_endpoint_descriptor *epread = NULL;
        struct usb_endpoint_descriptor *epwrite = NULL;
        struct usb_device *usb_dev = interface_to_usbdev(intf);
        struct usb_cdc_parsed_header h;
        struct acm *acm;
        int minor;
        int ctrlsize, readsize;
        u8 *buf;
        int call_intf_num = -1;
        int data_intf_num = -1;
        unsigned long quirks;
        int num_rx_buf;
        int i;
        int combined_interfaces = 0;
        struct device *tty_dev;
        int rv = -ENOMEM;
        int res;

        /* normal quirks */
        quirks = (unsigned long)id->driver_info;

        if (quirks == IGNORE_DEVICE)
                return -ENODEV;

        memset(&h, 0x00, sizeof(struct usb_cdc_parsed_header));

        num_rx_buf = (quirks == SINGLE_RX_URB) ? 1 : ACM_NR;

        /* handle quirks deadly to normal probing*/
        if (quirks == NO_UNION_NORMAL) {
                data_interface = usb_ifnum_to_if(usb_dev, 1);
                control_interface = usb_ifnum_to_if(usb_dev, 0);
                /* we would crash */
                if (!data_interface || !control_interface)
                        return -ENODEV;
                goto skip_normal_probe;
        } else if (quirks == NO_UNION_12) {
                data_interface = usb_ifnum_to_if(usb_dev, 2);
                control_interface = usb_ifnum_to_if(usb_dev, 1);
                if (!data_interface || !control_interface)
                         return -ENODEV;
                goto skip_normal_probe;
        }

        /* normal probing*/
        if (!buffer) {
                dev_err(&intf->dev, "Weird descriptor references\n");
                return -EINVAL;
        }

        if (!buflen) {
                if (intf->cur_altsetting->endpoint &&
                                intf->cur_altsetting->endpoint->extralen &&
                                intf->cur_altsetting->endpoint->extra) {
                        dev_dbg(&intf->dev,
                                "Seeking extra descriptors on endpoint\n");
                        buflen = intf->cur_altsetting->endpoint->extralen;
                        buffer = intf->cur_altsetting->endpoint->extra;
                } else {
                        dev_err(&intf->dev,
                                "Zero length descriptor references\n");
                        return -EINVAL;
                }
        }

        cdc_parse_cdc_header(&h, intf, buffer, buflen);
        union_header = h.usb_cdc_union_desc;
        cmgmd = h.usb_cdc_call_mgmt_descriptor;
        if (cmgmd)
                call_intf_num = cmgmd->bDataInterface;

        if (!union_header) {
                if (intf->cur_altsetting->desc.bNumEndpoints == 3) {
                        dev_dbg(&intf->dev, "No union descriptor, assuming single interface\n");
                        combined_interfaces = 1;
                        control_interface = data_interface = intf;
                        goto look_for_collapsed_interface;
                } else if (call_intf_num > 0) {
                        dev_dbg(&intf->dev, "No union descriptor, using call management descriptor\n");
                        data_intf_num = call_intf_num;
                        data_interface = usb_ifnum_to_if(usb_dev, data_intf_num);
                        control_interface = intf;
                } else {
                        dev_dbg(&intf->dev, "No union descriptor, giving up\n");
                        return -ENODEV;
                }
        } else {
                int class = -1;

                data_intf_num = union_header->bSlaveInterface0;
                control_interface = usb_ifnum_to_if(usb_dev, union_header->bMasterInterface0);
                data_interface = usb_ifnum_to_if(usb_dev, data_intf_num);

                if (control_interface)
                        class = control_interface->cur_altsetting->desc.bInterfaceClass;

                if (class != USB_CLASS_COMM && class != USB_CLASS_CDC_DATA) {
                        dev_dbg(&intf->dev, "Broken union descriptor, assuming single interface\n");
                        combined_interfaces = 1;
                        control_interface = data_interface = intf;
                        goto look_for_collapsed_interface;
                }
        }

        if (!control_interface || !data_interface) {
                dev_dbg(&intf->dev, "no interfaces\n");
                return -ENODEV;
        }

        if (data_intf_num != call_intf_num)
                dev_dbg(&intf->dev, "Separate call control interface. That is not fully supported.\n");

        if (control_interface == data_interface) {
                /* some broken devices designed for windows work this way */
                dev_warn(&intf->dev,"Control and data interfaces are not separated!\n");
                combined_interfaces = 1;
                /* a popular other OS doesn't use it */
                quirks |= NO_CAP_LINE;
                if (data_interface->cur_altsetting->desc.bNumEndpoints != 3) {
                        dev_err(&intf->dev, "This needs exactly 3 endpoints\n");
                        return -EINVAL;
                }
look_for_collapsed_interface:
                res = usb_find_common_endpoints(data_interface->cur_altsetting,
                                &epread, &epwrite, &epctrl, NULL);
                if (res)
                        return res;

                goto made_compressed_probe;
        }

skip_normal_probe:

        /*workaround for switched interfaces */
        if (data_interface->cur_altsetting->desc.bInterfaceClass != USB_CLASS_CDC_DATA) {
                if (control_interface->cur_altsetting->desc.bInterfaceClass == USB_CLASS_CDC_DATA) {
                        dev_dbg(&intf->dev,
                                "Your device has switched interfaces.\n");
                        swap(control_interface, data_interface);
                } else {
                        return -EINVAL;
                }
        }

        /* Accept probe requests only for the control interface */
        if (!combined_interfaces && intf != control_interface)
                return -ENODEV;

        if (data_interface->cur_altsetting->desc.bNumEndpoints < 2 ||
            control_interface->cur_altsetting->desc.bNumEndpoints == 0)
                return -EINVAL;

        epctrl = &control_interface->cur_altsetting->endpoint[0].desc;
        epread = &data_interface->cur_altsetting->endpoint[0].desc;
        epwrite = &data_interface->cur_altsetting->endpoint[1].desc;


        /* workaround for switched endpoints */
        if (!usb_endpoint_dir_in(epread)) {
                /* descriptors are swapped */
                dev_dbg(&intf->dev,
                        "The data interface has switched endpoints\n");
                swap(epread, epwrite);
        }
made_compressed_probe:
        dev_dbg(&intf->dev, "interfaces are valid\n");

        acm = kzalloc_obj(struct acm);
        if (!acm)
                return -ENOMEM;

        tty_port_init(&acm->port);
        acm->port.ops = &acm_port_ops;

        ctrlsize = usb_endpoint_maxp(epctrl);
        readsize = usb_endpoint_maxp(epread) *
                                (quirks == SINGLE_RX_URB ? 1 : 2);
        acm->combined_interfaces = combined_interfaces;
        acm->writesize = usb_endpoint_maxp(epwrite) * 20;
        acm->control = control_interface;
        acm->data = data_interface;

        usb_get_intf(acm->control); /* undone in destruct() */

        minor = acm_alloc_minor(acm);
        if (minor < 0) {
                acm->minor = ACM_MINOR_INVALID;
                goto err_put_port;
        }

        acm->minor = minor;
        acm->dev = usb_dev;
        if (h.usb_cdc_acm_descriptor)
                acm->ctrl_caps = h.usb_cdc_acm_descriptor->bmCapabilities;
        if (quirks & NO_CAP_LINE)
                acm->ctrl_caps &= ~USB_CDC_CAP_LINE;
        if (quirks & MISSING_CAP_BRK)
                acm->ctrl_caps |= USB_CDC_CAP_BRK;
        acm->ctrlsize = ctrlsize;
        acm->readsize = readsize;
        acm->rx_buflimit = num_rx_buf;
        INIT_DELAYED_WORK(&acm->dwork, acm_softint);
        init_waitqueue_head(&acm->wioctl);
        spin_lock_init(&acm->write_lock);
        spin_lock_init(&acm->read_lock);
        mutex_init(&acm->mutex);
        if (usb_endpoint_xfer_int(epread)) {
                acm->bInterval = epread->bInterval;
                acm->in = usb_rcvintpipe(usb_dev, epread->bEndpointAddress);
        } else {
                acm->in = usb_rcvbulkpipe(usb_dev, epread->bEndpointAddress);
        }
        if (usb_endpoint_xfer_int(epwrite))
                acm->out = usb_sndintpipe(usb_dev, epwrite->bEndpointAddress);
        else
                acm->out = usb_sndbulkpipe(usb_dev, epwrite->bEndpointAddress);
        init_usb_anchor(&acm->delayed);
        acm->quirks = quirks;

        buf = usb_alloc_coherent(usb_dev, ctrlsize, GFP_KERNEL, &acm->ctrl_dma);
        if (!buf)
                goto err_put_port;
        acm->ctrl_buffer = buf;

        if (acm_write_buffers_alloc(acm) < 0)
                goto err_free_ctrl_buffer;

        acm->ctrlurb = usb_alloc_urb(0, GFP_KERNEL);
        if (!acm->ctrlurb)
                goto err_free_write_buffers;

        for (i = 0; i < num_rx_buf; i++) {
                struct acm_rb *rb = &(acm->read_buffers[i]);
                struct urb *urb;

                rb->base = usb_alloc_coherent(acm->dev, readsize, GFP_KERNEL,
                                                                &rb->dma);
                if (!rb->base)
                        goto err_free_read_urbs;
                rb->index = i;
                rb->instance = acm;

                urb = usb_alloc_urb(0, GFP_KERNEL);
                if (!urb)
                        goto err_free_read_urbs;

                urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
                urb->transfer_dma = rb->dma;
                if (usb_endpoint_xfer_int(epread))
                        usb_fill_int_urb(urb, acm->dev, acm->in, rb->base,
                                         acm->readsize,
                                         acm_read_bulk_callback, rb,
                                         acm->bInterval);
                else
                        usb_fill_bulk_urb(urb, acm->dev, acm->in, rb->base,
                                          acm->readsize,
                                          acm_read_bulk_callback, rb);

                acm->read_urbs[i] = urb;
                __set_bit(i, &acm->read_urbs_free);
        }
        for (i = 0; i < ACM_NW; i++) {
                struct acm_wb *snd = &(acm->wb[i]);

                snd->urb = usb_alloc_urb(0, GFP_KERNEL);
                if (!snd->urb)
                        goto err_free_write_urbs;

                if (usb_endpoint_xfer_int(epwrite))
                        usb_fill_int_urb(snd->urb, usb_dev, acm->out,
                                NULL, acm->writesize, acm_write_bulk, snd, epwrite->bInterval);
                else
                        usb_fill_bulk_urb(snd->urb, usb_dev, acm->out,
                                NULL, acm->writesize, acm_write_bulk, snd);
                snd->urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
                if (quirks & SEND_ZERO_PACKET)
                        snd->urb->transfer_flags |= URB_ZERO_PACKET;
                snd->instance = acm;
        }

        usb_set_intfdata(intf, acm);

        i = device_create_file(&intf->dev, &dev_attr_bmCapabilities);
        if (i < 0)
                goto err_free_write_urbs;

        if (h.usb_cdc_country_functional_desc) { /* export the country data */
                struct usb_cdc_country_functional_desc * cfd =
                                        h.usb_cdc_country_functional_desc;

                acm->country_codes = kmalloc(cfd->bLength - 4, GFP_KERNEL);
                if (!acm->country_codes)
                        goto skip_countries;
                acm->country_code_size = cfd->bLength - 4;
                memcpy(acm->country_codes, cfd->wCountryCodes,
                                                        cfd->bLength - 4);
                acm->country_rel_date = cfd->iCountryCodeRelDate;

                i = device_create_file(&intf->dev, &dev_attr_wCountryCodes);
                if (i < 0) {
                        kfree(acm->country_codes);
                        acm->country_codes = NULL;
                        acm->country_code_size = 0;
                        goto skip_countries;
                }

                i = device_create_file(&intf->dev,
                                                &dev_attr_iCountryCodeRelDate);
                if (i < 0) {
                        device_remove_file(&intf->dev, &dev_attr_wCountryCodes);
                        kfree(acm->country_codes);
                        acm->country_codes = NULL;
                        acm->country_code_size = 0;
                        goto skip_countries;
                }
        }

skip_countries:
        usb_fill_int_urb(acm->ctrlurb, usb_dev,
                         usb_rcvintpipe(usb_dev, epctrl->bEndpointAddress),
                         acm->ctrl_buffer, ctrlsize, acm_ctrl_irq, acm,
                         /* works around buggy devices */
                         epctrl->bInterval ? epctrl->bInterval : 16);
        acm->ctrlurb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
        acm->ctrlurb->transfer_dma = acm->ctrl_dma;
        acm->notification_buffer = NULL;
        acm->nb_index = 0;
        acm->nb_size = 0;

        acm->line.dwDTERate = cpu_to_le32(9600);
        acm->line.bDataBits = 8;
        acm_set_line(acm, &acm->line);

        if (!acm->combined_interfaces) {
                rv = usb_driver_claim_interface(&acm_driver, data_interface, acm);
                if (rv)
                        goto err_remove_files;
        }

        if (quirks & CLEAR_HALT_CONDITIONS) {
                /* errors intentionally ignored */
                usb_clear_halt(usb_dev, acm->in);
                usb_clear_halt(usb_dev, acm->out);
        }

        tty_dev = tty_port_register_device(&acm->port, acm_tty_driver, minor,
                        &control_interface->dev);
        if (IS_ERR(tty_dev)) {
                rv = PTR_ERR(tty_dev);
                goto err_release_data_interface;
        }

        dev_info(&intf->dev, "ttyACM%d: USB ACM device\n", minor);

        return 0;

err_release_data_interface:
        if (!acm->combined_interfaces) {
                /* Clear driver data so that disconnect() returns early. */
                usb_set_intfdata(data_interface, NULL);
                usb_driver_release_interface(&acm_driver, data_interface);
        }
err_remove_files:
        if (acm->country_codes) {
                device_remove_file(&acm->control->dev,
                                &dev_attr_wCountryCodes);
                device_remove_file(&acm->control->dev,
                                &dev_attr_iCountryCodeRelDate);
        }
        device_remove_file(&acm->control->dev, &dev_attr_bmCapabilities);
err_free_write_urbs:
        for (i = 0; i < ACM_NW; i++)
                usb_free_urb(acm->wb[i].urb);
err_free_read_urbs:
        for (i = 0; i < num_rx_buf; i++)
                usb_free_urb(acm->read_urbs[i]);
        acm_read_buffers_free(acm);
        usb_free_urb(acm->ctrlurb);
err_free_write_buffers:
        acm_write_buffers_free(acm);
err_free_ctrl_buffer:
        usb_free_coherent(usb_dev, ctrlsize, acm->ctrl_buffer, acm->ctrl_dma);
err_put_port:
        tty_port_put(&acm->port);

        return rv;
}

static void acm_disconnect(struct usb_interface *intf)
{
        struct acm *acm = usb_get_intfdata(intf);
        int i;

        /* sibling interface is already cleaning up */
        if (!acm)
                return;

        acm->disconnected = true;
        /*
         * there is a circular dependency. acm_softint() can resubmit
         * the URBs in error handling so we need to block any
         * submission right away
         */
        acm_poison_urbs(acm);
        mutex_lock(&acm->mutex);
        if (acm->country_codes) {
                device_remove_file(&acm->control->dev,
                                &dev_attr_wCountryCodes);
                device_remove_file(&acm->control->dev,
                                &dev_attr_iCountryCodeRelDate);
        }
        wake_up_all(&acm->wioctl);
        device_remove_file(&acm->control->dev, &dev_attr_bmCapabilities);
        usb_set_intfdata(acm->control, NULL);
        usb_set_intfdata(acm->data, NULL);
        mutex_unlock(&acm->mutex);

        tty_port_tty_vhangup(&acm->port);

        cancel_delayed_work_sync(&acm->dwork);

        tty_unregister_device(acm_tty_driver, acm->minor);

        usb_free_urb(acm->ctrlurb);
        for (i = 0; i < ACM_NW; i++)
                usb_free_urb(acm->wb[i].urb);
        for (i = 0; i < acm->rx_buflimit; i++)
                usb_free_urb(acm->read_urbs[i]);
        acm_write_buffers_free(acm);
        usb_free_coherent(acm->dev, acm->ctrlsize, acm->ctrl_buffer, acm->ctrl_dma);
        acm_read_buffers_free(acm);

        kfree(acm->notification_buffer);

        if (!acm->combined_interfaces)
                usb_driver_release_interface(&acm_driver, intf == acm->control ?
                                        acm->data : acm->control);

        tty_port_put(&acm->port);
}

#ifdef CONFIG_PM
static int acm_suspend(struct usb_interface *intf, pm_message_t message)
{
        struct acm *acm = usb_get_intfdata(intf);
        int cnt;

        spin_lock_irq(&acm->write_lock);
        if (PMSG_IS_AUTO(message)) {
                if (acm->transmitting) {
                        spin_unlock_irq(&acm->write_lock);
                        return -EBUSY;
                }
        }
        cnt = acm->susp_count++;
        spin_unlock_irq(&acm->write_lock);

        if (cnt)
                return 0;

        acm_poison_urbs(acm);
        cancel_delayed_work_sync(&acm->dwork);
        acm->urbs_in_error_delay = 0;

        return 0;
}

static int acm_resume(struct usb_interface *intf)
{
        struct acm *acm = usb_get_intfdata(intf);
        struct urb *urb;
        int rv = 0;

        spin_lock_irq(&acm->write_lock);

        if (--acm->susp_count)
                goto out;

        acm_unpoison_urbs(acm);

        if (tty_port_initialized(&acm->port)) {
                rv = usb_submit_urb(acm->ctrlurb, GFP_ATOMIC);

                for (;;) {
                        urb = usb_get_from_anchor(&acm->delayed);
                        if (!urb)
                                break;

                        acm_start_wb(acm, urb->context);
                }

                /*
                 * delayed error checking because we must
                 * do the write path at all cost
                 */
                if (rv < 0)
                        goto out;

                rv = acm_submit_read_urbs(acm, GFP_ATOMIC);
        }
out:
        spin_unlock_irq(&acm->write_lock);

        return rv;
}

static int acm_reset_resume(struct usb_interface *intf)
{
        struct acm *acm = usb_get_intfdata(intf);

        if (tty_port_initialized(&acm->port))
                tty_port_tty_hangup(&acm->port, false);

        return acm_resume(intf);
}

#endif /* CONFIG_PM */

static int acm_pre_reset(struct usb_interface *intf)
{
        struct acm *acm = usb_get_intfdata(intf);

        clear_bit(EVENT_RX_STALL, &acm->flags);
        acm->nb_index = 0; /* pending control transfers are lost */

        return 0;
}

#define NOKIA_PCSUITE_ACM_INFO(x) \
                USB_DEVICE_AND_INTERFACE_INFO(0x0421, x, \
                USB_CLASS_COMM, USB_CDC_SUBCLASS_ACM, \
                USB_CDC_ACM_PROTO_VENDOR)

#define SAMSUNG_PCSUITE_ACM_INFO(x) \
                USB_DEVICE_AND_INTERFACE_INFO(0x04e7, x, \
                USB_CLASS_COMM, USB_CDC_SUBCLASS_ACM, \
                USB_CDC_ACM_PROTO_VENDOR)

/*
 * USB driver structure.
 */

static const struct usb_device_id acm_ids[] = {
        /* quirky and broken devices */
        { USB_DEVICE(0x0424, 0x274e), /* Microchip Technology, Inc. (formerly SMSC) */
          .driver_info = DISABLE_ECHO, }, /* DISABLE ECHO in termios flag */
        { USB_DEVICE(0x076d, 0x0006), /* Denso Cradle CU-321 */
        .driver_info = NO_UNION_NORMAL, },/* has no union descriptor */
        { USB_DEVICE(0x17ef, 0x7000), /* Lenovo USB modem */
        .driver_info = NO_UNION_NORMAL, },/* has no union descriptor */
        { USB_DEVICE(0x0870, 0x0001), /* Metricom GS Modem */
        .driver_info = NO_UNION_NORMAL, /* has no union descriptor */
        },
        { USB_DEVICE(0x045b, 0x023c),   /* Renesas R-Car H3 USB Download mode */
        .driver_info = DISABLE_ECHO,    /* Don't echo banner */
        },
        { USB_DEVICE(0x045b, 0x0247),   /* Renesas R-Car D3 USB Download mode */
        .driver_info = DISABLE_ECHO,    /* Don't echo banner */
        },
        { USB_DEVICE(0x045b, 0x0248),   /* Renesas R-Car M3-N USB Download mode */
        .driver_info = DISABLE_ECHO,    /* Don't echo banner */
        },
        { USB_DEVICE(0x045b, 0x024D),   /* Renesas R-Car E3 USB Download mode */
        .driver_info = DISABLE_ECHO,    /* Don't echo banner */
        },
        { USB_DEVICE(0x04b8, 0x0d12),   /* EPSON HMD Com&Sens */
        .driver_info = NO_UNION_12,     /* union descriptor is garbage */
        },
        { USB_DEVICE(0x0e8d, 0x0003), /* FIREFLY, MediaTek Inc; andrey.arapov@gmail.com */
        .driver_info = NO_UNION_NORMAL, /* has no union descriptor */
        },
        { USB_DEVICE(0x0e8d, 0x2000), /* MediaTek Inc Preloader */
        .driver_info = DISABLE_ECHO, /* DISABLE ECHO in termios flag */
        },
        { USB_DEVICE(0x0e8d, 0x3329), /* MediaTek Inc GPS */
        .driver_info = NO_UNION_NORMAL, /* has no union descriptor */
        },
        { USB_DEVICE(0x0482, 0x0203), /* KYOCERA AH-K3001V */
        .driver_info = NO_UNION_NORMAL, /* has no union descriptor */
        },
        { USB_DEVICE(0x079b, 0x000f), /* BT On-Air USB MODEM */
        .driver_info = NO_UNION_NORMAL, /* has no union descriptor */
        },
        { USB_DEVICE(0x0ace, 0x1602), /* ZyDAS 56K USB MODEM */
        .driver_info = SINGLE_RX_URB,
        },
        { USB_DEVICE(0x0ace, 0x1608), /* ZyDAS 56K USB MODEM */
        .driver_info = SINGLE_RX_URB, /* firmware bug */
        },
        { USB_DEVICE(0x0ace, 0x1611), /* ZyDAS 56K USB MODEM - new version */
        .driver_info = SINGLE_RX_URB, /* firmware bug */
        },
        { USB_DEVICE(0x11ca, 0x0201), /* VeriFone Mx870 Gadget Serial */
        .driver_info = SINGLE_RX_URB,
        },
        { USB_DEVICE(0x1901, 0x0006), /* GE Healthcare Patient Monitor UI Controller */
        .driver_info = DISABLE_ECHO, /* DISABLE ECHO in termios flag */
        },
        { USB_DEVICE(0x1965, 0x0018), /* Uniden UBC125XLT */
        .driver_info = NO_UNION_NORMAL, /* has no union descriptor */
        },
        { USB_DEVICE(0x22b8, 0x7000), /* Motorola Q Phone */
        .driver_info = NO_UNION_NORMAL, /* has no union descriptor */
        },
        { USB_DEVICE(0x0803, 0x3095), /* Zoom Telephonics Model 3095F USB MODEM */
        .driver_info = NO_UNION_NORMAL, /* has no union descriptor */
        },
        { USB_DEVICE(0x0572, 0x1321), /* Conexant USB MODEM CX93010 */
        .driver_info = NO_UNION_NORMAL, /* has no union descriptor */
        },
        { USB_DEVICE(0x0572, 0x1324), /* Conexant USB MODEM RD02-D400 */
        .driver_info = NO_UNION_NORMAL, /* has no union descriptor */
        },
        { USB_DEVICE(0x0572, 0x1328), /* Shiro / Aztech USB MODEM UM-3100 */
        .driver_info = NO_UNION_NORMAL, /* has no union descriptor */
        },
        { USB_DEVICE(0x0572, 0x1349), /* Hiro (Conexant) USB MODEM H50228 */
        .driver_info = NO_UNION_NORMAL, /* has no union descriptor */
        },
        { USB_DEVICE(0x20df, 0x0001), /* Simtec Electronics Entropy Key */
        .driver_info = QUIRK_CONTROL_LINE_STATE, },
        { USB_DEVICE(0x2184, 0x001c) }, /* GW Instek AFG-2225 */
        { USB_DEVICE(0x2184, 0x0036) }, /* GW Instek AFG-125 */
        { USB_DEVICE(0x22b8, 0x6425), /* Motorola MOTOMAGX phones */
        },
        /* Motorola H24 HSPA module: */
        { USB_DEVICE(0x22b8, 0x2d91) }, /* modem                                */
        { USB_DEVICE(0x22b8, 0x2d92),   /* modem           + diagnostics        */
        .driver_info = NO_UNION_NORMAL, /* handle only modem interface          */
        },
        { USB_DEVICE(0x22b8, 0x2d93),   /* modem + AT port                      */
        .driver_info = NO_UNION_NORMAL, /* handle only modem interface          */
        },
        { USB_DEVICE(0x22b8, 0x2d95),   /* modem + AT port + diagnostics        */
        .driver_info = NO_UNION_NORMAL, /* handle only modem interface          */
        },
        { USB_DEVICE(0x22b8, 0x2d96),   /* modem                         + NMEA */
        .driver_info = NO_UNION_NORMAL, /* handle only modem interface          */
        },
        { USB_DEVICE(0x22b8, 0x2d97),   /* modem           + diagnostics + NMEA */
        .driver_info = NO_UNION_NORMAL, /* handle only modem interface          */
        },
        { USB_DEVICE(0x22b8, 0x2d99),   /* modem + AT port               + NMEA */
        .driver_info = NO_UNION_NORMAL, /* handle only modem interface          */
        },
        { USB_DEVICE(0x22b8, 0x2d9a),   /* modem + AT port + diagnostics + NMEA */
        .driver_info = NO_UNION_NORMAL, /* handle only modem interface          */
        },

        { USB_DEVICE(0x0572, 0x1329), /* Hummingbird huc56s (Conexant) */
        .driver_info = NO_UNION_NORMAL, /* union descriptor misplaced on
                                           data interface instead of
                                           communications interface.
                                           Maybe we should define a new
                                           quirk for this. */
        },
        { USB_DEVICE(0x0572, 0x1340), /* Conexant CX93010-2x UCMxx */
        .driver_info = NO_UNION_NORMAL,
        },
        { USB_DEVICE(0x05f9, 0x4002), /* PSC Scanning, Magellan 800i */
        .driver_info = NO_UNION_NORMAL,
        },
        { USB_DEVICE(0x1bbb, 0x0003), /* Alcatel OT-I650 */
        .driver_info = NO_UNION_NORMAL, /* reports zero length descriptor */
        },
        { USB_DEVICE(0x1576, 0x03b1), /* Maretron USB100 */
        .driver_info = NO_UNION_NORMAL, /* reports zero length descriptor */
        },
        { USB_DEVICE(0xfff0, 0x0100), /* DATECS FP-2000 */
        .driver_info = NO_UNION_NORMAL, /* reports zero length descriptor */
        },
        { USB_DEVICE(0x09d8, 0x0320), /* Elatec GmbH TWN3 */
        .driver_info = NO_UNION_NORMAL, /* has misplaced union descriptor */
        },
        { USB_DEVICE(0x0c26, 0x0020), /* Icom ICF3400 Serie */
        .driver_info = NO_UNION_NORMAL, /* reports zero length descriptor */
        },
        { USB_DEVICE(0x0ca6, 0xa050), /* Castles VEGA3000 */
        .driver_info = NO_UNION_NORMAL, /* reports zero length descriptor */
        },

        { USB_DEVICE(0x2912, 0x0001), /* ATOL FPrint */
        .driver_info = CLEAR_HALT_CONDITIONS,
        },

        /* Nokia S60 phones expose two ACM channels. The first is
         * a modem and is picked up by the standard AT-command
         * information below. The second is 'vendor-specific' but
         * is treated as a serial device at the S60 end, so we want
         * to expose it on Linux too. */
        { NOKIA_PCSUITE_ACM_INFO(0x042D), }, /* Nokia 3250 */
        { NOKIA_PCSUITE_ACM_INFO(0x04D8), }, /* Nokia 5500 Sport */
        { NOKIA_PCSUITE_ACM_INFO(0x04C9), }, /* Nokia E50 */
        { NOKIA_PCSUITE_ACM_INFO(0x0419), }, /* Nokia E60 */
        { NOKIA_PCSUITE_ACM_INFO(0x044D), }, /* Nokia E61 */
        { NOKIA_PCSUITE_ACM_INFO(0x0001), }, /* Nokia E61i */
        { NOKIA_PCSUITE_ACM_INFO(0x0475), }, /* Nokia E62 */
        { NOKIA_PCSUITE_ACM_INFO(0x0508), }, /* Nokia E65 */
        { NOKIA_PCSUITE_ACM_INFO(0x0418), }, /* Nokia E70 */
        { NOKIA_PCSUITE_ACM_INFO(0x0425), }, /* Nokia N71 */
        { NOKIA_PCSUITE_ACM_INFO(0x0486), }, /* Nokia N73 */
        { NOKIA_PCSUITE_ACM_INFO(0x04DF), }, /* Nokia N75 */
        { NOKIA_PCSUITE_ACM_INFO(0x000e), }, /* Nokia N77 */
        { NOKIA_PCSUITE_ACM_INFO(0x0445), }, /* Nokia N80 */
        { NOKIA_PCSUITE_ACM_INFO(0x042F), }, /* Nokia N91 & N91 8GB */
        { NOKIA_PCSUITE_ACM_INFO(0x048E), }, /* Nokia N92 */
        { NOKIA_PCSUITE_ACM_INFO(0x0420), }, /* Nokia N93 */
        { NOKIA_PCSUITE_ACM_INFO(0x04E6), }, /* Nokia N93i  */
        { NOKIA_PCSUITE_ACM_INFO(0x04B2), }, /* Nokia 5700 XpressMusic */
        { NOKIA_PCSUITE_ACM_INFO(0x0134), }, /* Nokia 6110 Navigator (China) */
        { NOKIA_PCSUITE_ACM_INFO(0x046E), }, /* Nokia 6110 Navigator */
        { NOKIA_PCSUITE_ACM_INFO(0x002f), }, /* Nokia 6120 classic &  */
        { NOKIA_PCSUITE_ACM_INFO(0x0088), }, /* Nokia 6121 classic */
        { NOKIA_PCSUITE_ACM_INFO(0x00fc), }, /* Nokia 6124 classic */
        { NOKIA_PCSUITE_ACM_INFO(0x0042), }, /* Nokia E51 */
        { NOKIA_PCSUITE_ACM_INFO(0x00b0), }, /* Nokia E66 */
        { NOKIA_PCSUITE_ACM_INFO(0x00ab), }, /* Nokia E71 */
        { NOKIA_PCSUITE_ACM_INFO(0x0481), }, /* Nokia N76 */
        { NOKIA_PCSUITE_ACM_INFO(0x0007), }, /* Nokia N81 & N81 8GB */
        { NOKIA_PCSUITE_ACM_INFO(0x0071), }, /* Nokia N82 */
        { NOKIA_PCSUITE_ACM_INFO(0x04F0), }, /* Nokia N95 & N95-3 NAM */
        { NOKIA_PCSUITE_ACM_INFO(0x0070), }, /* Nokia N95 8GB  */
        { NOKIA_PCSUITE_ACM_INFO(0x0099), }, /* Nokia 6210 Navigator, RM-367 */
        { NOKIA_PCSUITE_ACM_INFO(0x0128), }, /* Nokia 6210 Navigator, RM-419 */
        { NOKIA_PCSUITE_ACM_INFO(0x008f), }, /* Nokia 6220 Classic */
        { NOKIA_PCSUITE_ACM_INFO(0x00a0), }, /* Nokia 6650 */
        { NOKIA_PCSUITE_ACM_INFO(0x007b), }, /* Nokia N78 */
        { NOKIA_PCSUITE_ACM_INFO(0x0094), }, /* Nokia N85 */
        { NOKIA_PCSUITE_ACM_INFO(0x003a), }, /* Nokia N96 & N96-3  */
        { NOKIA_PCSUITE_ACM_INFO(0x00e9), }, /* Nokia 5320 XpressMusic */
        { NOKIA_PCSUITE_ACM_INFO(0x0108), }, /* Nokia 5320 XpressMusic 2G */
        { NOKIA_PCSUITE_ACM_INFO(0x01f5), }, /* Nokia N97, RM-505 */
        { NOKIA_PCSUITE_ACM_INFO(0x02e3), }, /* Nokia 5230, RM-588 */
        { NOKIA_PCSUITE_ACM_INFO(0x0178), }, /* Nokia E63 */
        { NOKIA_PCSUITE_ACM_INFO(0x010e), }, /* Nokia E75 */
        { NOKIA_PCSUITE_ACM_INFO(0x02d9), }, /* Nokia 6760 Slide */
        { NOKIA_PCSUITE_ACM_INFO(0x01d0), }, /* Nokia E52 */
        { NOKIA_PCSUITE_ACM_INFO(0x0223), }, /* Nokia E72 */
        { NOKIA_PCSUITE_ACM_INFO(0x0275), }, /* Nokia X6 */
        { NOKIA_PCSUITE_ACM_INFO(0x026c), }, /* Nokia N97 Mini */
        { NOKIA_PCSUITE_ACM_INFO(0x0154), }, /* Nokia 5800 XpressMusic */
        { NOKIA_PCSUITE_ACM_INFO(0x04ce), }, /* Nokia E90 */
        { NOKIA_PCSUITE_ACM_INFO(0x01d4), }, /* Nokia E55 */
        { NOKIA_PCSUITE_ACM_INFO(0x0302), }, /* Nokia N8 */
        { NOKIA_PCSUITE_ACM_INFO(0x0335), }, /* Nokia E7 */
        { NOKIA_PCSUITE_ACM_INFO(0x03cd), }, /* Nokia C7 */
        { SAMSUNG_PCSUITE_ACM_INFO(0x6651), }, /* Samsung GTi8510 (INNOV8) */

        /* Support for Owen devices */
        { USB_DEVICE(0x03eb, 0x0030), }, /* Owen SI30 */

        /* NOTE: non-Nokia COMM/ACM/0xff is likely MSFT RNDIS... NOT a modem! */

#if IS_ENABLED(CONFIG_INPUT_IMS_PCU)
        { USB_DEVICE(0x04d8, 0x0082),   /* Application mode */
        .driver_info = IGNORE_DEVICE,
        },
        { USB_DEVICE(0x04d8, 0x0083),   /* Bootloader mode */
        .driver_info = IGNORE_DEVICE,
        },
#endif

#if IS_ENABLED(CONFIG_IR_TOY)
        { USB_DEVICE(0x04d8, 0xfd08),
        .driver_info = IGNORE_DEVICE,
        },

        { USB_DEVICE(0x04d8, 0xf58b),
        .driver_info = IGNORE_DEVICE,
        },
#endif

#if IS_ENABLED(CONFIG_USB_SERIAL_XR)
        { USB_DEVICE(0x04e2, 0x1400), .driver_info = IGNORE_DEVICE },
        { USB_DEVICE(0x04e2, 0x1401), .driver_info = IGNORE_DEVICE },
        { USB_DEVICE(0x04e2, 0x1402), .driver_info = IGNORE_DEVICE },
        { USB_DEVICE(0x04e2, 0x1403), .driver_info = IGNORE_DEVICE },
        { USB_DEVICE(0x04e2, 0x1410), .driver_info = IGNORE_DEVICE },
        { USB_DEVICE(0x04e2, 0x1411), .driver_info = IGNORE_DEVICE },
        { USB_DEVICE(0x04e2, 0x1412), .driver_info = IGNORE_DEVICE },
        { USB_DEVICE(0x04e2, 0x1414), .driver_info = IGNORE_DEVICE },
        { USB_DEVICE(0x04e2, 0x1420), .driver_info = IGNORE_DEVICE },
        { USB_DEVICE(0x04e2, 0x1422), .driver_info = IGNORE_DEVICE },
        { USB_DEVICE(0x04e2, 0x1424), .driver_info = IGNORE_DEVICE },
#endif

        /*Samsung phone in firmware update mode */
        { USB_DEVICE(0x04e8, 0x685d),
        .driver_info = IGNORE_DEVICE,
        },

        /* Exclude Infineon Flash Loader utility */
        { USB_DEVICE(0x058b, 0x0041),
        .driver_info = IGNORE_DEVICE,
        },

        /* Exclude ETAS ES58x */
        { USB_DEVICE(0x108c, 0x0159), /* ES581.4 */
        .driver_info = IGNORE_DEVICE,
        },
        { USB_DEVICE(0x108c, 0x0168), /* ES582.1 */
        .driver_info = IGNORE_DEVICE,
        },
        { USB_DEVICE(0x108c, 0x0169), /* ES584.1 */
        .driver_info = IGNORE_DEVICE,
        },

        { USB_DEVICE(0x1bc7, 0x0021), /* Telit 3G ACM only composition */
        .driver_info = SEND_ZERO_PACKET,
        },
        { USB_DEVICE(0x1bc7, 0x0023), /* Telit 3G ACM + ECM composition */
        .driver_info = SEND_ZERO_PACKET,
        },

        /* Exclude Goodix Fingerprint Reader */
        { USB_DEVICE(0x27c6, 0x5395),
        .driver_info = IGNORE_DEVICE,
        },

        /* Exclude Heimann Sensor GmbH USB appset demo */
        { USB_DEVICE(0x32a7, 0x0000),
        .driver_info = IGNORE_DEVICE,
        },

        /* CH343 supports CAP_BRK, but doesn't advertise it */
        { USB_DEVICE(0x1a86, 0x55d3), .driver_info = MISSING_CAP_BRK, },

        /* control interfaces without any protocol set */
        { USB_INTERFACE_INFO(USB_CLASS_COMM, USB_CDC_SUBCLASS_ACM,
                USB_CDC_PROTO_NONE) },

        /* control interfaces with various AT-command sets */
        { USB_INTERFACE_INFO(USB_CLASS_COMM, USB_CDC_SUBCLASS_ACM,
                USB_CDC_ACM_PROTO_AT_V25TER) },
        { USB_INTERFACE_INFO(USB_CLASS_COMM, USB_CDC_SUBCLASS_ACM,
                USB_CDC_ACM_PROTO_AT_PCCA101) },
        { USB_INTERFACE_INFO(USB_CLASS_COMM, USB_CDC_SUBCLASS_ACM,
                USB_CDC_ACM_PROTO_AT_PCCA101_WAKE) },
        { USB_INTERFACE_INFO(USB_CLASS_COMM, USB_CDC_SUBCLASS_ACM,
                USB_CDC_ACM_PROTO_AT_GSM) },
        { USB_INTERFACE_INFO(USB_CLASS_COMM, USB_CDC_SUBCLASS_ACM,
                USB_CDC_ACM_PROTO_AT_3G) },
        { USB_INTERFACE_INFO(USB_CLASS_COMM, USB_CDC_SUBCLASS_ACM,
                USB_CDC_ACM_PROTO_AT_CDMA) },

        { USB_DEVICE(0x1519, 0x0452), /* Intel 7260 modem */
        .driver_info = SEND_ZERO_PACKET,
        },

        { }
};

MODULE_DEVICE_TABLE(usb, acm_ids);

static struct usb_driver acm_driver = {
        .name =         "cdc_acm",
        .probe =        acm_probe,
        .disconnect =   acm_disconnect,
#ifdef CONFIG_PM
        .suspend =      acm_suspend,
        .resume =       acm_resume,
        .reset_resume = acm_reset_resume,
#endif
        .pre_reset =    acm_pre_reset,
        .id_table =     acm_ids,
#ifdef CONFIG_PM
        .supports_autosuspend = 1,
#endif
        .disable_hub_initiated_lpm = 1,
};

/*
 * TTY driver structures.
 */

static const struct tty_operations acm_ops = {
        .install =              acm_tty_install,
        .open =                 acm_tty_open,
        .close =                acm_tty_close,
        .cleanup =              acm_tty_cleanup,
        .hangup =               acm_tty_hangup,
        .write =                acm_tty_write,
        .write_room =           acm_tty_write_room,
        .flush_buffer =         acm_tty_flush_buffer,
        .ioctl =                acm_tty_ioctl,
        .throttle =             acm_tty_throttle,
        .unthrottle =           acm_tty_unthrottle,
        .chars_in_buffer =      acm_tty_chars_in_buffer,
        .break_ctl =            acm_tty_break_ctl,
        .set_termios =          acm_tty_set_termios,
        .tiocmget =             acm_tty_tiocmget,
        .tiocmset =             acm_tty_tiocmset,
        .get_serial =           get_serial_info,
        .set_serial =           set_serial_info,
        .get_icount =           acm_tty_get_icount,
};

/*
 * Init / exit.
 */

static int __init acm_init(void)
{
        int retval;
        acm_tty_driver = tty_alloc_driver(ACM_TTY_MINORS, TTY_DRIVER_REAL_RAW |
                        TTY_DRIVER_DYNAMIC_DEV);
        if (IS_ERR(acm_tty_driver))
                return PTR_ERR(acm_tty_driver);
        acm_tty_driver->driver_name = "acm",
        acm_tty_driver->name = "ttyACM",
        acm_tty_driver->major = ACM_TTY_MAJOR,
        acm_tty_driver->minor_start = 0,
        acm_tty_driver->type = TTY_DRIVER_TYPE_SERIAL,
        acm_tty_driver->subtype = SERIAL_TYPE_NORMAL,
        acm_tty_driver->init_termios = tty_std_termios;
        acm_tty_driver->init_termios.c_cflag = B9600 | CS8 | CREAD |
                                                                HUPCL | CLOCAL;
        tty_set_operations(acm_tty_driver, &acm_ops);

        retval = tty_register_driver(acm_tty_driver);
        if (retval) {
                tty_driver_kref_put(acm_tty_driver);
                return retval;
        }

        retval = usb_register(&acm_driver);
        if (retval) {
                tty_unregister_driver(acm_tty_driver);
                tty_driver_kref_put(acm_tty_driver);
                return retval;
        }

        printk(KERN_INFO KBUILD_MODNAME ": " DRIVER_DESC "\n");

        return 0;
}

static void __exit acm_exit(void)
{
        usb_deregister(&acm_driver);
        tty_unregister_driver(acm_tty_driver);
        tty_driver_kref_put(acm_tty_driver);
        idr_destroy(&acm_minors);
}

module_init(acm_init);
module_exit(acm_exit);

MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL");
MODULE_ALIAS_CHARDEV_MAJOR(ACM_TTY_MAJOR);