/*
  USB Driver for Sierra Wireless

  Copyright (C) 2006, 2007, 2008  Kevin Lloyd <klloyd@sierrawireless.com>,

  Copyright (C) 2008, 2009  Elina Pasheva, Matthew Safar, Rory Filer
                        <linux@sierrawireless.com>

  IMPORTANT DISCLAIMER: This driver is not commercially supported by
  Sierra Wireless. Use at your own risk.

  This driver is free software; you can redistribute it and/or modify
  it under the terms of Version 2 of the GNU General Public License as
  published by the Free Software Foundation.

  Portions based on the option driver by Matthias Urlichs <smurf@smurf.noris.de>
  Whom based his on the Keyspan driver by Hugh Blemings <hugh@blemings.org>
*/
/* Uncomment to log function calls */
/* #define DEBUG */

#define DRIVER_AUTHOR "Kevin Lloyd, Elina Pasheva, Matthew Safar, Rory Filer"
#define DRIVER_DESC "USB Driver for Sierra Wireless USB modems"

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

#define SWIMS_USB_REQUEST_SetPower      0x00
#define SWIMS_USB_REQUEST_SetNmea       0x07

#define N_IN_URB_HM     8
#define N_OUT_URB_HM    64
#define N_IN_URB        4
#define N_OUT_URB       4
#define IN_BUFLEN       4096

#define MAX_TRANSFER            (PAGE_SIZE - 512)
/* MAX_TRANSFER is chosen so that the VM is not stressed by
   allocations > PAGE_SIZE and the number of packets in a page
   is an integer 512 is the largest possible packet on EHCI */

static bool nmea;

/* Used in interface blacklisting */
struct sierra_iface_info {
        const u32 infolen;      /* number of interface numbers on blacklist */
        const u8  *ifaceinfo;   /* pointer to the array holding the numbers */
};

struct sierra_intf_private {
        spinlock_t susp_lock;
        unsigned int suspended:1;
        int in_flight;
        unsigned int open_ports;
};

static int sierra_set_power_state(struct usb_device *udev, __u16 swiState)
{
        return usb_control_msg(udev, usb_sndctrlpipe(udev, 0),
                        SWIMS_USB_REQUEST_SetPower,     /* __u8 request      */
                        USB_TYPE_VENDOR,                /* __u8 request type */
                        swiState,                       /* __u16 value       */
                        0,                              /* __u16 index       */
                        NULL,                           /* void *data        */
                        0,                              /* __u16 size        */
                        USB_CTRL_SET_TIMEOUT);          /* int timeout       */
}

static int sierra_vsc_set_nmea(struct usb_device *udev, __u16 enable)
{
        return usb_control_msg(udev, usb_sndctrlpipe(udev, 0),
                        SWIMS_USB_REQUEST_SetNmea,      /* __u8 request      */
                        USB_TYPE_VENDOR,                /* __u8 request type */
                        enable,                         /* __u16 value       */
                        0x0000,                         /* __u16 index       */
                        NULL,                           /* void *data        */
                        0,                              /* __u16 size        */
                        USB_CTRL_SET_TIMEOUT);          /* int timeout       */
}

static int sierra_calc_num_ports(struct usb_serial *serial)
{
        int num_ports = 0;
        u8 ifnum, numendpoints;

        ifnum = serial->interface->cur_altsetting->desc.bInterfaceNumber;
        numendpoints = serial->interface->cur_altsetting->desc.bNumEndpoints;

        /* Dummy interface present on some SKUs should be ignored */
        if (ifnum == 0x99)
                num_ports = 0;
        else if (numendpoints <= 3)
                num_ports = 1;
        else
                num_ports = (numendpoints-1)/2;
        return num_ports;
}

static int is_blacklisted(const u8 ifnum,
                                const struct sierra_iface_info *blacklist)
{
        const u8  *info;
        int i;

        if (blacklist) {
                info = blacklist->ifaceinfo;

                for (i = 0; i < blacklist->infolen; i++) {
                        if (info[i] == ifnum)
                                return 1;
                }
        }
        return 0;
}

static int is_himemory(const u8 ifnum,
                                const struct sierra_iface_info *himemorylist)
{
        const u8  *info;
        int i;

        if (himemorylist) {
                info = himemorylist->ifaceinfo;

                for (i=0; i < himemorylist->infolen; i++) {
                        if (info[i] == ifnum)
                                return 1;
                }
        }
        return 0;
}

static int sierra_calc_interface(struct usb_serial *serial)
{
        int interface;
        struct usb_interface *p_interface;
        struct usb_host_interface *p_host_interface;

        /* Get the interface structure pointer from the serial struct */
        p_interface = serial->interface;

        /* Get a pointer to the host interface structure */
        p_host_interface = p_interface->cur_altsetting;

        /* read the interface descriptor for this active altsetting
         * to find out the interface number we are on
        */
        interface = p_host_interface->desc.bInterfaceNumber;

        return interface;
}

static int sierra_probe(struct usb_serial *serial,
                        const struct usb_device_id *id)
{
        int result = 0;
        struct usb_device *udev;
        u8 ifnum;

        udev = serial->dev;
        ifnum = sierra_calc_interface(serial);

        /*
         * If this interface supports more than 1 alternate
         * select the 2nd one
         */
        if (serial->interface->num_altsetting == 2) {
                dev_dbg(&udev->dev, "Selecting alt setting for interface %d\n",
                        ifnum);
                /* We know the alternate setting is 1 for the MC8785 */
                usb_set_interface(udev, ifnum, 1);
        }

        /* ifnum could have changed - by calling usb_set_interface */
        ifnum = sierra_calc_interface(serial);

        if (is_blacklisted(ifnum,
                                (struct sierra_iface_info *)id->driver_info)) {
                dev_dbg(&serial->dev->dev,
                        "Ignoring blacklisted interface #%d\n", ifnum);
                return -ENODEV;
        }

        return result;
}

/* interfaces with higher memory requirements */
static const u8 hi_memory_typeA_ifaces[] = { 0, 2 };
static const struct sierra_iface_info typeA_interface_list = {
        .infolen = ARRAY_SIZE(hi_memory_typeA_ifaces),
        .ifaceinfo = hi_memory_typeA_ifaces,
};

static const u8 hi_memory_typeB_ifaces[] = { 3, 4, 5, 6 };
static const struct sierra_iface_info typeB_interface_list = {
        .infolen = ARRAY_SIZE(hi_memory_typeB_ifaces),
        .ifaceinfo = hi_memory_typeB_ifaces,
};

/* 'blacklist' of interfaces not served by this driver */
static const u8 direct_ip_non_serial_ifaces[] = { 7, 8, 9, 10, 11, 19, 20 };
static const struct sierra_iface_info direct_ip_interface_blacklist = {
        .infolen = ARRAY_SIZE(direct_ip_non_serial_ifaces),
        .ifaceinfo = direct_ip_non_serial_ifaces,
};

static const struct usb_device_id id_table[] = {
        { USB_DEVICE(0x0F3D, 0x0112) }, /* Airprime/Sierra PC 5220 */
        { USB_DEVICE(0x03F0, 0x1B1D) }, /* HP ev2200 a.k.a MC5720 */
        { USB_DEVICE(0x03F0, 0x211D) }, /* HP ev2210 a.k.a MC5725 */
        { USB_DEVICE(0x03F0, 0x1E1D) }, /* HP hs2300 a.k.a MC8775 */

        { USB_DEVICE(0x1199, 0x0017) }, /* Sierra Wireless EM5625 */
        { USB_DEVICE(0x1199, 0x0018) }, /* Sierra Wireless MC5720 */
        { USB_DEVICE(0x1199, 0x0218) }, /* Sierra Wireless MC5720 */
        { USB_DEVICE(0x1199, 0x0020) }, /* Sierra Wireless MC5725 */
        { USB_DEVICE(0x1199, 0x0220) }, /* Sierra Wireless MC5725 */
        { USB_DEVICE(0x1199, 0x0022) }, /* Sierra Wireless EM5725 */
        { USB_DEVICE(0x1199, 0x0024) }, /* Sierra Wireless MC5727 */
        { USB_DEVICE(0x1199, 0x0224) }, /* Sierra Wireless MC5727 */
        { USB_DEVICE(0x1199, 0x0019) }, /* Sierra Wireless AirCard 595 */
        { USB_DEVICE(0x1199, 0x0021) }, /* Sierra Wireless AirCard 597E */
        { USB_DEVICE(0x1199, 0x0112) }, /* Sierra Wireless AirCard 580 */
        { USB_DEVICE(0x1199, 0x0120) }, /* Sierra Wireless USB Dongle 595U */
        { USB_DEVICE(0x1199, 0x0301) }, /* Sierra Wireless USB Dongle 250U */
        /* Sierra Wireless C597 */
        { USB_DEVICE_AND_INTERFACE_INFO(0x1199, 0x0023, 0xFF, 0xFF, 0xFF) },
        /* Sierra Wireless T598 */
        { USB_DEVICE_AND_INTERFACE_INFO(0x1199, 0x0025, 0xFF, 0xFF, 0xFF) },
        { USB_DEVICE(0x1199, 0x0026) }, /* Sierra Wireless T11 */
        { USB_DEVICE(0x1199, 0x0027) }, /* Sierra Wireless AC402 */
        { USB_DEVICE(0x1199, 0x0028) }, /* Sierra Wireless MC5728 */
        { USB_DEVICE(0x1199, 0x0029) }, /* Sierra Wireless Device */

        { USB_DEVICE(0x1199, 0x6802) }, /* Sierra Wireless MC8755 */
        { USB_DEVICE(0x1199, 0x6803) }, /* Sierra Wireless MC8765 */
        { USB_DEVICE(0x1199, 0x6804) }, /* Sierra Wireless MC8755 */
        { USB_DEVICE(0x1199, 0x6805) }, /* Sierra Wireless MC8765 */
        { USB_DEVICE(0x1199, 0x6808) }, /* Sierra Wireless MC8755 */
        { USB_DEVICE(0x1199, 0x6809) }, /* Sierra Wireless MC8765 */
        { USB_DEVICE(0x1199, 0x6812) }, /* Sierra Wireless MC8775 & AC 875U */
        { USB_DEVICE(0x1199, 0x6813) }, /* Sierra Wireless MC8775 */
        { USB_DEVICE(0x1199, 0x6815) }, /* Sierra Wireless MC8775 */
        { USB_DEVICE(0x1199, 0x6816) }, /* Sierra Wireless MC8775 */
        { USB_DEVICE(0x1199, 0x6820) }, /* Sierra Wireless AirCard 875 */
        { USB_DEVICE(0x1199, 0x6821) }, /* Sierra Wireless AirCard 875U */
        { USB_DEVICE(0x1199, 0x6822) }, /* Sierra Wireless AirCard 875E */
        { USB_DEVICE(0x1199, 0x6832) }, /* Sierra Wireless MC8780 */
        { USB_DEVICE(0x1199, 0x6833) }, /* Sierra Wireless MC8781 */
        { USB_DEVICE(0x1199, 0x6834) }, /* Sierra Wireless MC8780 */
        { USB_DEVICE(0x1199, 0x6835) }, /* Sierra Wireless MC8781 */
        { USB_DEVICE(0x1199, 0x6838) }, /* Sierra Wireless MC8780 */
        { USB_DEVICE(0x1199, 0x6839) }, /* Sierra Wireless MC8781 */
        { USB_DEVICE(0x1199, 0x683A) }, /* Sierra Wireless MC8785 */
        { USB_DEVICE(0x1199, 0x683B) }, /* Sierra Wireless MC8785 Composite */
        /* Sierra Wireless MC8790, MC8791, MC8792 Composite */
        { USB_DEVICE(0x1199, 0x683C) },
        { USB_DEVICE(0x1199, 0x683D) }, /* Sierra Wireless MC8791 Composite */
        /* Sierra Wireless MC8790, MC8791, MC8792 */
        { USB_DEVICE(0x1199, 0x683E) },
        { USB_DEVICE(0x1199, 0x6850) }, /* Sierra Wireless AirCard 880 */
        { USB_DEVICE(0x1199, 0x6851) }, /* Sierra Wireless AirCard 881 */
        { USB_DEVICE(0x1199, 0x6852) }, /* Sierra Wireless AirCard 880 E */
        { USB_DEVICE(0x1199, 0x6853) }, /* Sierra Wireless AirCard 881 E */
        { USB_DEVICE(0x1199, 0x6855) }, /* Sierra Wireless AirCard 880 U */
        { USB_DEVICE(0x1199, 0x6856) }, /* Sierra Wireless AirCard 881 U */
        { USB_DEVICE(0x1199, 0x6859) }, /* Sierra Wireless AirCard 885 E */
        { USB_DEVICE(0x1199, 0x685A) }, /* Sierra Wireless AirCard 885 E */
        /* Sierra Wireless C885 */
        { USB_DEVICE_AND_INTERFACE_INFO(0x1199, 0x6880, 0xFF, 0xFF, 0xFF)},
        /* Sierra Wireless C888, Air Card 501, USB 303, USB 304 */
        { USB_DEVICE_AND_INTERFACE_INFO(0x1199, 0x6890, 0xFF, 0xFF, 0xFF)},
        /* Sierra Wireless C22/C33 */
        { USB_DEVICE_AND_INTERFACE_INFO(0x1199, 0x6891, 0xFF, 0xFF, 0xFF)},
        /* Sierra Wireless HSPA Non-Composite Device */
        { USB_DEVICE_AND_INTERFACE_INFO(0x1199, 0x6892, 0xFF, 0xFF, 0xFF)},
        { USB_DEVICE(0x1199, 0x6893) }, /* Sierra Wireless Device */
        /* Sierra Wireless Direct IP modems */
        { USB_DEVICE_AND_INTERFACE_INFO(0x1199, 0x68A3, 0xFF, 0xFF, 0xFF),
          .driver_info = (kernel_ulong_t)&direct_ip_interface_blacklist
        },
        { USB_DEVICE_AND_INTERFACE_INFO(0x1199, 0x68AA, 0xFF, 0xFF, 0xFF),
          .driver_info = (kernel_ulong_t)&direct_ip_interface_blacklist
        },
        { USB_DEVICE(0x1199, 0x68AB) }, /* Sierra Wireless AR8550 */
        /* AT&T Direct IP LTE modems */
        { USB_DEVICE_AND_INTERFACE_INFO(0x0F3D, 0x68AA, 0xFF, 0xFF, 0xFF),
          .driver_info = (kernel_ulong_t)&direct_ip_interface_blacklist
        },
        /* Airprime/Sierra Wireless Direct IP modems */
        { USB_DEVICE_AND_INTERFACE_INFO(0x0F3D, 0x68A3, 0xFF, 0xFF, 0xFF),
          .driver_info = (kernel_ulong_t)&direct_ip_interface_blacklist
        },

        { }
};
MODULE_DEVICE_TABLE(usb, id_table);


struct sierra_port_private {
        spinlock_t lock;        /* lock the structure */
        int outstanding_urbs;   /* number of out urbs in flight */
        struct usb_anchor active;
        struct usb_anchor delayed;

        int num_out_urbs;
        int num_in_urbs;
        /* Input endpoints and buffers for this port */
        struct urb *in_urbs[N_IN_URB_HM];

        /* Settings for the port */
        int rts_state;  /* Handshaking pins (outputs) */
        int dtr_state;
        int cts_state;  /* Handshaking pins (inputs) */
        int dsr_state;
        int dcd_state;
        int ri_state;
};

static int sierra_send_setup(struct usb_serial_port *port)
{
        struct usb_serial *serial = port->serial;
        struct sierra_port_private *portdata;
        __u16 interface = 0;
        int val = 0;
        int do_send = 0;
        int retval;

        portdata = usb_get_serial_port_data(port);

        if (portdata->dtr_state)
                val |= 0x01;
        if (portdata->rts_state)
                val |= 0x02;

        /* If composite device then properly report interface */
        if (serial->num_ports == 1) {
                interface = sierra_calc_interface(serial);
                /* Control message is sent only to interfaces with
                 * interrupt_in endpoints
                 */
                if (port->interrupt_in_urb) {
                        /* send control message */
                        do_send = 1;
                }
        }

        /* Otherwise the need to do non-composite mapping */
        else {
                if (port->bulk_out_endpointAddress == 2)
                        interface = 0;
                else if (port->bulk_out_endpointAddress == 4)
                        interface = 1;
                else if (port->bulk_out_endpointAddress == 5)
                        interface = 2;

                do_send = 1;
        }
        if (!do_send)
                return 0;

        retval = usb_autopm_get_interface(serial->interface);
        if (retval < 0)
                return retval;

        retval = usb_control_msg(serial->dev, usb_sndctrlpipe(serial->dev, 0),
                0x22, 0x21, val, interface, NULL, 0, USB_CTRL_SET_TIMEOUT);
        usb_autopm_put_interface(serial->interface);

        return retval;
}

static int sierra_tiocmget(struct tty_struct *tty)
{
        struct usb_serial_port *port = tty->driver_data;
        unsigned int value;
        struct sierra_port_private *portdata;

        portdata = usb_get_serial_port_data(port);

        value = ((portdata->rts_state) ? TIOCM_RTS : 0) |
                ((portdata->dtr_state) ? TIOCM_DTR : 0) |
                ((portdata->cts_state) ? TIOCM_CTS : 0) |
                ((portdata->dsr_state) ? TIOCM_DSR : 0) |
                ((portdata->dcd_state) ? TIOCM_CAR : 0) |
                ((portdata->ri_state) ? TIOCM_RNG : 0);

        return value;
}

static int sierra_tiocmset(struct tty_struct *tty,
                        unsigned int set, unsigned int clear)
{
        struct usb_serial_port *port = tty->driver_data;
        struct sierra_port_private *portdata;

        portdata = usb_get_serial_port_data(port);

        if (set & TIOCM_RTS)
                portdata->rts_state = 1;
        if (set & TIOCM_DTR)
                portdata->dtr_state = 1;

        if (clear & TIOCM_RTS)
                portdata->rts_state = 0;
        if (clear & TIOCM_DTR)
                portdata->dtr_state = 0;
        return sierra_send_setup(port);
}

static void sierra_release_urb(struct urb *urb)
{
        if (urb) {
                kfree(urb->transfer_buffer);
                usb_free_urb(urb);
        }
}

static void sierra_outdat_callback(struct urb *urb)
{
        struct usb_serial_port *port = urb->context;
        struct sierra_port_private *portdata = usb_get_serial_port_data(port);
        struct sierra_intf_private *intfdata;
        int status = urb->status;

        intfdata = usb_get_serial_data(port->serial);

        /* free up the transfer buffer, as usb_free_urb() does not do this */
        kfree(urb->transfer_buffer);
        usb_autopm_put_interface_async(port->serial->interface);
        if (status)
                dev_dbg(&port->dev, "%s - nonzero write bulk status "
                    "received: %d\n", __func__, status);

        spin_lock(&portdata->lock);
        --portdata->outstanding_urbs;
        spin_unlock(&portdata->lock);
        spin_lock(&intfdata->susp_lock);
        --intfdata->in_flight;
        spin_unlock(&intfdata->susp_lock);

        usb_serial_port_softint(port);
}

/* Write */
static int sierra_write(struct tty_struct *tty, struct usb_serial_port *port,
                                        const unsigned char *buf, int count)
{
        struct sierra_port_private *portdata;
        struct sierra_intf_private *intfdata;
        struct usb_serial *serial = port->serial;
        unsigned long flags;
        unsigned char *buffer;
        struct urb *urb;
        size_t writesize = min((size_t)count, (size_t)MAX_TRANSFER);
        int retval = 0;

        /* verify that we actually have some data to write */
        if (count == 0)
                return 0;

        portdata = usb_get_serial_port_data(port);
        intfdata = usb_get_serial_data(serial);

        dev_dbg(&port->dev, "%s: write (%zd bytes)\n", __func__, writesize);
        spin_lock_irqsave(&portdata->lock, flags);
        dev_dbg(&port->dev, "%s - outstanding_urbs: %d\n", __func__,
                portdata->outstanding_urbs);
        if (portdata->outstanding_urbs > portdata->num_out_urbs) {
                spin_unlock_irqrestore(&portdata->lock, flags);
                dev_dbg(&port->dev, "%s - write limit hit\n", __func__);
                return 0;
        }
        portdata->outstanding_urbs++;
        dev_dbg(&port->dev, "%s - 1, outstanding_urbs: %d\n", __func__,
                portdata->outstanding_urbs);
        spin_unlock_irqrestore(&portdata->lock, flags);

        retval = usb_autopm_get_interface_async(serial->interface);
        if (retval < 0) {
                spin_lock_irqsave(&portdata->lock, flags);
                portdata->outstanding_urbs--;
                spin_unlock_irqrestore(&portdata->lock, flags);
                goto error_simple;
        }

        buffer = kmalloc(writesize, GFP_ATOMIC);
        if (!buffer) {
                retval = -ENOMEM;
                goto error_no_buffer;
        }

        urb = usb_alloc_urb(0, GFP_ATOMIC);
        if (!urb) {
                retval = -ENOMEM;
                goto error_no_urb;
        }

        memcpy(buffer, buf, writesize);

        usb_serial_debug_data(&port->dev, __func__, writesize, buffer);

        usb_fill_bulk_urb(urb, serial->dev,
                          usb_sndbulkpipe(serial->dev,
                                          port->bulk_out_endpointAddress),
                          buffer, writesize, sierra_outdat_callback, port);

        /* Handle the need to send a zero length packet */
        urb->transfer_flags |= URB_ZERO_PACKET;

        spin_lock_irqsave(&intfdata->susp_lock, flags);

        if (intfdata->suspended) {
                usb_anchor_urb(urb, &portdata->delayed);
                spin_unlock_irqrestore(&intfdata->susp_lock, flags);
                goto skip_power;
        } else {
                usb_anchor_urb(urb, &portdata->active);
        }
        /* send it down the pipe */
        retval = usb_submit_urb(urb, GFP_ATOMIC);
        if (retval) {
                usb_unanchor_urb(urb);
                spin_unlock_irqrestore(&intfdata->susp_lock, flags);
                dev_err(&port->dev, "%s - usb_submit_urb(write bulk) failed "
                        "with status = %d\n", __func__, retval);
                goto error;
        } else {
                intfdata->in_flight++;
                spin_unlock_irqrestore(&intfdata->susp_lock, flags);
        }

skip_power:
        /* we are done with this urb, so let the host driver
         * really free it when it is finished with it */
        usb_free_urb(urb);

        return writesize;
error:
        usb_free_urb(urb);
error_no_urb:
        kfree(buffer);
error_no_buffer:
        spin_lock_irqsave(&portdata->lock, flags);
        --portdata->outstanding_urbs;
        dev_dbg(&port->dev, "%s - 2. outstanding_urbs: %d\n", __func__,
                portdata->outstanding_urbs);
        spin_unlock_irqrestore(&portdata->lock, flags);
        usb_autopm_put_interface_async(serial->interface);
error_simple:
        return retval;
}

static void sierra_indat_callback(struct urb *urb)
{
        int err;
        int endpoint;
        struct usb_serial_port *port;
        unsigned char *data = urb->transfer_buffer;
        int status = urb->status;

        endpoint = usb_pipeendpoint(urb->pipe);
        port = urb->context;

        if (status) {
                dev_dbg(&port->dev, "%s: nonzero status: %d on"
                        " endpoint %02x\n", __func__, status, endpoint);
        } else {
                if (urb->actual_length) {
                        tty_insert_flip_string(&port->port, data,
                                urb->actual_length);
                        tty_flip_buffer_push(&port->port);

                        usb_serial_debug_data(&port->dev, __func__,
                                              urb->actual_length, data);
                } else {
                        dev_dbg(&port->dev, "%s: empty read urb"
                                " received\n", __func__);
                }
        }

        /* Resubmit urb so we continue receiving */
        if (status != -ESHUTDOWN && status != -EPERM) {
                usb_mark_last_busy(port->serial->dev);
                err = usb_submit_urb(urb, GFP_ATOMIC);
                if (err && err != -EPERM)
                        dev_err(&port->dev, "resubmit read urb failed."
                                "(%d)\n", err);
        }
}

static void sierra_instat_callback(struct urb *urb)
{
        int err;
        int status = urb->status;
        struct usb_serial_port *port =  urb->context;
        struct sierra_port_private *portdata = usb_get_serial_port_data(port);
        struct usb_serial *serial = port->serial;

        dev_dbg(&port->dev, "%s: urb %p port %p has data %p\n", __func__,
                urb, port, portdata);

        if (status == 0) {
                struct usb_ctrlrequest *req_pkt =
                                (struct usb_ctrlrequest *)urb->transfer_buffer;

                if (!req_pkt) {
                        dev_dbg(&port->dev, "%s: NULL req_pkt\n",
                                __func__);
                        return;
                }
                if ((req_pkt->bRequestType == 0xA1) &&
                                (req_pkt->bRequest == 0x20)) {
                        int old_dcd_state;
                        unsigned char signals = *((unsigned char *)
                                        urb->transfer_buffer +
                                        sizeof(struct usb_ctrlrequest));

                        dev_dbg(&port->dev, "%s: signal x%x\n", __func__,
                                signals);

                        old_dcd_state = portdata->dcd_state;
                        portdata->cts_state = 1;
                        portdata->dcd_state = ((signals & 0x01) ? 1 : 0);
                        portdata->dsr_state = ((signals & 0x02) ? 1 : 0);
                        portdata->ri_state = ((signals & 0x08) ? 1 : 0);

                        if (old_dcd_state && !portdata->dcd_state)
                                tty_port_tty_hangup(&port->port, true);
                } else {
                        dev_dbg(&port->dev, "%s: type %x req %x\n",
                                __func__, req_pkt->bRequestType,
                                req_pkt->bRequest);
                }
        } else
                dev_dbg(&port->dev, "%s: error %d\n", __func__, status);

        /* Resubmit urb so we continue receiving IRQ data */
        if (status != -ESHUTDOWN && status != -ENOENT) {
                usb_mark_last_busy(serial->dev);
                err = usb_submit_urb(urb, GFP_ATOMIC);
                if (err && err != -EPERM)
                        dev_err(&port->dev, "%s: resubmit intr urb "
                                "failed. (%d)\n", __func__, err);
        }
}

static int sierra_write_room(struct tty_struct *tty)
{
        struct usb_serial_port *port = tty->driver_data;
        struct sierra_port_private *portdata = usb_get_serial_port_data(port);
        unsigned long flags;

        /* try to give a good number back based on if we have any free urbs at
         * this point in time */
        spin_lock_irqsave(&portdata->lock, flags);
        if (portdata->outstanding_urbs > (portdata->num_out_urbs * 2) / 3) {
                spin_unlock_irqrestore(&portdata->lock, flags);
                dev_dbg(&port->dev, "%s - write limit hit\n", __func__);
                return 0;
        }
        spin_unlock_irqrestore(&portdata->lock, flags);

        return 2048;
}

static int sierra_chars_in_buffer(struct tty_struct *tty)
{
        struct usb_serial_port *port = tty->driver_data;
        struct sierra_port_private *portdata = usb_get_serial_port_data(port);
        unsigned long flags;
        int chars;

        /* NOTE: This overcounts somewhat. */
        spin_lock_irqsave(&portdata->lock, flags);
        chars = portdata->outstanding_urbs * MAX_TRANSFER;
        spin_unlock_irqrestore(&portdata->lock, flags);

        dev_dbg(&port->dev, "%s - %d\n", __func__, chars);

        return chars;
}

static void sierra_stop_rx_urbs(struct usb_serial_port *port)
{
        int i;
        struct sierra_port_private *portdata = usb_get_serial_port_data(port);

        for (i = 0; i < portdata->num_in_urbs; i++)
                usb_kill_urb(portdata->in_urbs[i]);

        usb_kill_urb(port->interrupt_in_urb);
}

static int sierra_submit_rx_urbs(struct usb_serial_port *port, gfp_t mem_flags)
{
        int ok_cnt;
        int err = -EINVAL;
        int i;
        struct urb *urb;
        struct sierra_port_private *portdata = usb_get_serial_port_data(port);

        ok_cnt = 0;
        for (i = 0; i < portdata->num_in_urbs; i++) {
                urb = portdata->in_urbs[i];
                if (!urb)
                        continue;
                err = usb_submit_urb(urb, mem_flags);
                if (err) {
                        dev_err(&port->dev, "%s: submit urb failed: %d\n",
                                __func__, err);
                } else {
                        ok_cnt++;
                }
        }

        if (ok_cnt && port->interrupt_in_urb) {
                err = usb_submit_urb(port->interrupt_in_urb, mem_flags);
                if (err) {
                        dev_err(&port->dev, "%s: submit intr urb failed: %d\n",
                                __func__, err);
                }
        }

        if (ok_cnt > 0) /* at least one rx urb submitted */
                return 0;
        else
                return err;
}

static struct urb *sierra_setup_urb(struct usb_serial *serial, int endpoint,
                                        int dir, void *ctx, int len,
                                        gfp_t mem_flags,
                                        usb_complete_t callback)
{
        struct urb      *urb;
        u8              *buf;

        urb = usb_alloc_urb(0, mem_flags);
        if (!urb)
                return NULL;

        buf = kmalloc(len, mem_flags);
        if (buf) {
                /* Fill URB using supplied data */
                usb_fill_bulk_urb(urb, serial->dev,
                        usb_sndbulkpipe(serial->dev, endpoint) | dir,
                        buf, len, callback, ctx);

                dev_dbg(&serial->dev->dev, "%s %c u : %p d:%p\n", __func__,
                                dir == USB_DIR_IN ? 'i' : 'o', urb, buf);
        } else {
                sierra_release_urb(urb);
                urb = NULL;
        }

        return urb;
}

static void sierra_close(struct usb_serial_port *port)
{
        int i;
        struct usb_serial *serial = port->serial;
        struct sierra_port_private *portdata;
        struct sierra_intf_private *intfdata = usb_get_serial_data(serial);
        struct urb *urb;

        portdata = usb_get_serial_port_data(port);

        /*
         * Need to take susp_lock to make sure port is not already being
         * resumed, but no need to hold it due to ASYNC_INITIALIZED.
         */
        spin_lock_irq(&intfdata->susp_lock);
        if (--intfdata->open_ports == 0)
                serial->interface->needs_remote_wakeup = 0;
        spin_unlock_irq(&intfdata->susp_lock);

        for (;;) {
                urb = usb_get_from_anchor(&portdata->delayed);
                if (!urb)
                        break;
                kfree(urb->transfer_buffer);
                usb_free_urb(urb);
                usb_autopm_put_interface_async(serial->interface);
                spin_lock(&portdata->lock);
                portdata->outstanding_urbs--;
                spin_unlock(&portdata->lock);
        }

        sierra_stop_rx_urbs(port);
        usb_kill_anchored_urbs(&portdata->active);

        for (i = 0; i < portdata->num_in_urbs; i++) {
                sierra_release_urb(portdata->in_urbs[i]);
                portdata->in_urbs[i] = NULL;
        }

        usb_autopm_get_interface_no_resume(serial->interface);
}

static int sierra_open(struct tty_struct *tty, struct usb_serial_port *port)
{
        struct sierra_port_private *portdata;
        struct usb_serial *serial = port->serial;
        struct sierra_intf_private *intfdata = usb_get_serial_data(serial);
        int i;
        int err;
        int endpoint;
        struct urb *urb;

        portdata = usb_get_serial_port_data(port);

        endpoint = port->bulk_in_endpointAddress;
        for (i = 0; i < portdata->num_in_urbs; i++) {
                urb = sierra_setup_urb(serial, endpoint, USB_DIR_IN, port,
                                        IN_BUFLEN, GFP_KERNEL,
                                        sierra_indat_callback);
                portdata->in_urbs[i] = urb;
        }
        /* clear halt condition */
        usb_clear_halt(serial->dev,
                        usb_sndbulkpipe(serial->dev, endpoint) | USB_DIR_IN);

        err = sierra_submit_rx_urbs(port, GFP_KERNEL);
        if (err)
                goto err_submit;

        spin_lock_irq(&intfdata->susp_lock);
        if (++intfdata->open_ports == 1)
                serial->interface->needs_remote_wakeup = 1;
        spin_unlock_irq(&intfdata->susp_lock);
        usb_autopm_put_interface(serial->interface);

        return 0;

err_submit:
        sierra_stop_rx_urbs(port);

        for (i = 0; i < portdata->num_in_urbs; i++) {
                sierra_release_urb(portdata->in_urbs[i]);
                portdata->in_urbs[i] = NULL;
        }

        return err;
}


static void sierra_dtr_rts(struct usb_serial_port *port, int on)
{
        struct sierra_port_private *portdata;

        portdata = usb_get_serial_port_data(port);
        portdata->rts_state = on;
        portdata->dtr_state = on;

        sierra_send_setup(port);
}

static int sierra_startup(struct usb_serial *serial)
{
        struct sierra_intf_private *intfdata;

        intfdata = kzalloc(sizeof(*intfdata), GFP_KERNEL);
        if (!intfdata)
                return -ENOMEM;

        spin_lock_init(&intfdata->susp_lock);

        usb_set_serial_data(serial, intfdata);

        /* Set Device mode to D0 */
        sierra_set_power_state(serial->dev, 0x0000);

        /* Check NMEA and set */
        if (nmea)
                sierra_vsc_set_nmea(serial->dev, 1);

        return 0;
}

static void sierra_release(struct usb_serial *serial)
{
        struct sierra_intf_private *intfdata;

        intfdata = usb_get_serial_data(serial);
        kfree(intfdata);
}

static int sierra_port_probe(struct usb_serial_port *port)
{
        struct usb_serial *serial = port->serial;
        struct sierra_port_private *portdata;
        const struct sierra_iface_info *himemoryp;
        u8 ifnum;

        portdata = kzalloc(sizeof(*portdata), GFP_KERNEL);
        if (!portdata)
                return -ENOMEM;

        spin_lock_init(&portdata->lock);
        init_usb_anchor(&portdata->active);
        init_usb_anchor(&portdata->delayed);

        /* Assume low memory requirements */
        portdata->num_out_urbs = N_OUT_URB;
        portdata->num_in_urbs  = N_IN_URB;

        /* Determine actual memory requirements */
        if (serial->num_ports == 1) {
                /* Get interface number for composite device */
                ifnum = sierra_calc_interface(serial);
                himemoryp = &typeB_interface_list;
        } else {
                /* This is really the usb-serial port number of the interface
                 * rather than the interface number.
                 */
                ifnum = port->port_number;
                himemoryp = &typeA_interface_list;
        }

        if (is_himemory(ifnum, himemoryp)) {
                portdata->num_out_urbs = N_OUT_URB_HM;
                portdata->num_in_urbs  = N_IN_URB_HM;
        }

        dev_dbg(&port->dev,
                        "Memory usage (urbs) interface #%d, in=%d, out=%d\n",
                        ifnum, portdata->num_in_urbs, portdata->num_out_urbs);

        usb_set_serial_port_data(port, portdata);

        return 0;
}

static int sierra_port_remove(struct usb_serial_port *port)
{
        struct sierra_port_private *portdata;

        portdata = usb_get_serial_port_data(port);
        usb_set_serial_port_data(port, NULL);
        kfree(portdata);

        return 0;
}

#ifdef CONFIG_PM
static void stop_read_write_urbs(struct usb_serial *serial)
{
        int i;
        struct usb_serial_port *port;
        struct sierra_port_private *portdata;

        /* Stop reading/writing urbs */
        for (i = 0; i < serial->num_ports; ++i) {
                port = serial->port[i];
                portdata = usb_get_serial_port_data(port);
                if (!portdata)
                        continue;
                sierra_stop_rx_urbs(port);
                usb_kill_anchored_urbs(&portdata->active);
        }
}

static int sierra_suspend(struct usb_serial *serial, pm_message_t message)
{
        struct sierra_intf_private *intfdata = usb_get_serial_data(serial);

        spin_lock_irq(&intfdata->susp_lock);
        if (PMSG_IS_AUTO(message)) {
                if (intfdata->in_flight) {
                        spin_unlock_irq(&intfdata->susp_lock);
                        return -EBUSY;
                }
        }
        intfdata->suspended = 1;
        spin_unlock_irq(&intfdata->susp_lock);

        stop_read_write_urbs(serial);

        return 0;
}

/* Caller must hold susp_lock. */
static int sierra_submit_delayed_urbs(struct usb_serial_port *port)
{
        struct sierra_port_private *portdata = usb_get_serial_port_data(port);
        struct sierra_intf_private *intfdata;
        struct urb *urb;
        int ec = 0;
        int err;

        intfdata = usb_get_serial_data(port->serial);

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

                usb_anchor_urb(urb, &portdata->active);
                intfdata->in_flight++;
                err = usb_submit_urb(urb, GFP_ATOMIC);
                if (err) {
                        dev_err(&port->dev, "%s - submit urb failed: %d",
                                        __func__, err);
                        ec++;
                        intfdata->in_flight--;
                        usb_unanchor_urb(urb);
                        kfree(urb->transfer_buffer);
                        usb_free_urb(urb);

                        spin_lock(&portdata->lock);
                        portdata->outstanding_urbs--;
                        spin_unlock(&portdata->lock);
                }
        }

        if (ec)
                return -EIO;

        return 0;
}

static int sierra_resume(struct usb_serial *serial)
{
        struct usb_serial_port *port;
        struct sierra_intf_private *intfdata = usb_get_serial_data(serial);
        int ec = 0;
        int i, err;

        spin_lock_irq(&intfdata->susp_lock);
        for (i = 0; i < serial->num_ports; i++) {
                port = serial->port[i];

                if (!test_bit(ASYNCB_INITIALIZED, &port->port.flags))
                        continue;

                err = sierra_submit_delayed_urbs(port);
                if (err)
                        ec++;

                err = sierra_submit_rx_urbs(port, GFP_ATOMIC);
                if (err)
                        ec++;
        }
        intfdata->suspended = 0;
        spin_unlock_irq(&intfdata->susp_lock);

        return ec ? -EIO : 0;
}

#else
#define sierra_suspend NULL
#define sierra_resume NULL
#endif

static struct usb_serial_driver sierra_device = {
        .driver = {
                .owner =        THIS_MODULE,
                .name =         "sierra",
        },
        .description       = "Sierra USB modem",
        .id_table          = id_table,
        .calc_num_ports    = sierra_calc_num_ports,
        .probe             = sierra_probe,
        .open              = sierra_open,
        .close             = sierra_close,
        .dtr_rts           = sierra_dtr_rts,
        .write             = sierra_write,
        .write_room        = sierra_write_room,
        .chars_in_buffer   = sierra_chars_in_buffer,
        .tiocmget          = sierra_tiocmget,
        .tiocmset          = sierra_tiocmset,
        .attach            = sierra_startup,
        .release           = sierra_release,
        .port_probe        = sierra_port_probe,
        .port_remove       = sierra_port_remove,
        .suspend           = sierra_suspend,
        .resume            = sierra_resume,
        .read_int_callback = sierra_instat_callback,
};

static struct usb_serial_driver * const serial_drivers[] = {
        &sierra_device, NULL
};

module_usb_serial_driver(serial_drivers, id_table);

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

module_param(nmea, bool, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(nmea, "NMEA streaming");