usb serial: Add generic USB wwan support

The generic USB serial code is ill-suited for high-speed USB wwan devices,
resulting in the option driver. However, other non-option devices may also
gain similar benefits from not using the generic code. Factorise out the
non-option specific code from the option driver and make it available to
other users.

Signed-off-by: Matthew Garrett <mjg@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

4 files changed, 736 insertions, 0 deletions

diff --git a/drivers/usb/serial/Kconfig b/drivers/usb/serial/Kconfig
index 5f777c20f2e2..e399efdb91e5 100644
--- a/drivers/usb/serial/Kconfig
+++ b/drivers/usb/serial/Kconfig
@@ -576,6 +576,9 @@ config USB_SERIAL_XIRCOM
           To compile this driver as a module, choose M here: the
           module will be called keyspan_pda.
 
+config USB_SERIAL_WWAN
+        tristate
+
 config USB_SERIAL_OPTION
         tristate "USB driver for GSM and CDMA modems"
         help
diff --git a/drivers/usb/serial/Makefile b/drivers/usb/serial/Makefile
index 3203614e3892..e54c728c016e 100644
--- a/drivers/usb/serial/Makefile
+++ b/drivers/usb/serial/Makefile
@@ -52,6 +52,7 @@ obj-$(CONFIG_USB_SERIAL_SIEMENS_MPI)		+= siemens_mpi.o
 obj-$(CONFIG_USB_SERIAL_SIERRAWIRELESS)         += sierra.o
 obj-$(CONFIG_USB_SERIAL_SPCP8X5)                += spcp8x5.o
 obj-$(CONFIG_USB_SERIAL_SYMBOL)                 += symbolserial.o
+obj-$(CONFIG_USB_SERIAL_WWAN)                   += usb_wwan.o
 obj-$(CONFIG_USB_SERIAL_TI)                     += ti_usb_3410_5052.o
 obj-$(CONFIG_USB_SERIAL_VISOR)                  += visor.o
 obj-$(CONFIG_USB_SERIAL_WHITEHEAT)              += whiteheat.o
diff --git a/drivers/usb/serial/usb-wwan.h b/drivers/usb/serial/usb-wwan.h
new file mode 100644
index 000000000000..2be298a1305b
--- /dev/null
+++ b/drivers/usb/serial/usb-wwan.h
@@ -0,0 +1,67 @@
+/*
+ * Definitions for USB serial mobile broadband cards
+ */
+
+#ifndef __LINUX_USB_USB_WWAN
+#define __LINUX_USB_USB_WWAN
+
+extern void usb_wwan_dtr_rts(struct usb_serial_port *port, int on);
+extern int usb_wwan_open(struct tty_struct *tty, struct usb_serial_port *port);
+extern void usb_wwan_close(struct usb_serial_port *port);
+extern int usb_wwan_startup(struct usb_serial *serial);
+extern void usb_wwan_disconnect(struct usb_serial *serial);
+extern void usb_wwan_release(struct usb_serial *serial);
+extern int usb_wwan_write_room(struct tty_struct *tty);
+extern void usb_wwan_set_termios(struct tty_struct *tty,
+                                 struct usb_serial_port *port,
+                                 struct ktermios *old);
+extern int usb_wwan_tiocmget(struct tty_struct *tty, struct file *file);
+extern int usb_wwan_tiocmset(struct tty_struct *tty, struct file *file,
+                             unsigned int set, unsigned int clear);
+extern int usb_wwan_send_setup(struct usb_serial_port *port);
+extern int usb_wwan_write(struct tty_struct *tty, struct usb_serial_port *port,
+                          const unsigned char *buf, int count);
+extern int usb_wwan_chars_in_buffer(struct tty_struct *tty);
+#ifdef CONFIG_PM
+extern int usb_wwan_suspend(struct usb_serial *serial, pm_message_t message);
+extern int usb_wwan_resume(struct usb_serial *serial);
+#endif
+
+/* per port private data */
+
+#define N_IN_URB 4
+#define N_OUT_URB 4
+#define IN_BUFLEN 4096
+#define OUT_BUFLEN 4096
+
+struct usb_wwan_intf_private {
+        spinlock_t susp_lock;
+        unsigned int suspended:1;
+        int in_flight;
+        int (*send_setup) (struct usb_serial_port *port);
+        void *private;
+};
+
+struct usb_wwan_port_private {
+        /* Input endpoints and buffer for this port */
+        struct urb *in_urbs[N_IN_URB];
+        u8 *in_buffer[N_IN_URB];
+        /* Output endpoints and buffer for this port */
+        struct urb *out_urbs[N_OUT_URB];
+        u8 *out_buffer[N_OUT_URB];
+        unsigned long out_busy; /* Bit vector of URBs in use */
+        int opened;
+        struct usb_anchor delayed;
+
+        /* 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;
+
+        unsigned long tx_start_time[N_OUT_URB];
+};
+
+#endif /* __LINUX_USB_USB_WWAN */
diff --git a/drivers/usb/serial/usb_wwan.c b/drivers/usb/serial/usb_wwan.c
new file mode 100644
index 000000000000..0c70b4a621bb
--- /dev/null
+++ b/drivers/usb/serial/usb_wwan.c
@@ -0,0 +1,665 @@
+/*
+  USB Driver layer for GSM modems
+
+  Copyright (C) 2005  Matthias Urlichs <smurf@smurf.noris.de>
+
+  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 copied from the Keyspan driver by Hugh Blemings <hugh@blemings.org>
+
+  History: see the git log.
+
+  Work sponsored by: Sigos GmbH, Germany <info@sigos.de>
+
+  This driver exists because the "normal" serial driver doesn't work too well
+  with GSM modems. Issues:
+  - data loss -- one single Receive URB is not nearly enough
+  - controlling the baud rate doesn't make sense
+*/
+
+#define DRIVER_VERSION "v0.7.2"
+#define DRIVER_AUTHOR "Matthias Urlichs <smurf@smurf.noris.de>"
+#define DRIVER_DESC "USB Driver for GSM modems"
+
+#include <linux/kernel.h>
+#include <linux/jiffies.h>
+#include <linux/errno.h>
+#include <linux/slab.h>
+#include <linux/tty.h>
+#include <linux/tty_flip.h>
+#include <linux/module.h>
+#include <linux/bitops.h>
+#include <linux/usb.h>
+#include <linux/usb/serial.h>
+#include "usb-wwan.h"
+
+static int debug;
+
+void usb_wwan_dtr_rts(struct usb_serial_port *port, int on)
+{
+        struct usb_serial *serial = port->serial;
+        struct usb_wwan_port_private *portdata;
+
+        struct usb_wwan_intf_private *intfdata;
+
+        dbg("%s", __func__);
+
+        intfdata = port->serial->private;
+
+        if (!intfdata->send_setup)
+                return;
+
+        portdata = usb_get_serial_port_data(port);
+        mutex_lock(&serial->disc_mutex);
+        portdata->rts_state = on;
+        portdata->dtr_state = on;
+        if (serial->dev)
+                intfdata->send_setup(port);
+        mutex_unlock(&serial->disc_mutex);
+}
+EXPORT_SYMBOL(usb_wwan_dtr_rts);
+
+void usb_wwan_set_termios(struct tty_struct *tty,
+                          struct usb_serial_port *port,
+                          struct ktermios *old_termios)
+{
+        struct usb_wwan_intf_private *intfdata = port->serial->private;
+
+        dbg("%s", __func__);
+
+        /* Doesn't support option setting */
+        tty_termios_copy_hw(tty->termios, old_termios);
+
+        if (intfdata->send_setup)
+                intfdata->send_setup(port);
+}
+EXPORT_SYMBOL(usb_wwan_set_termios);
+
+int usb_wwan_tiocmget(struct tty_struct *tty, struct file *file)
+{
+        struct usb_serial_port *port = tty->driver_data;
+        unsigned int value;
+        struct usb_wwan_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;
+}
+EXPORT_SYMBOL(usb_wwan_tiocmget);
+
+int usb_wwan_tiocmset(struct tty_struct *tty, struct file *file,
+                      unsigned int set, unsigned int clear)
+{
+        struct usb_serial_port *port = tty->driver_data;
+        struct usb_wwan_port_private *portdata;
+        struct usb_wwan_intf_private *intfdata;
+
+        portdata = usb_get_serial_port_data(port);
+        intfdata = port->serial->private;
+
+        if (!intfdata->send_setup)
+                return -EINVAL;
+
+        /* FIXME: what locks portdata fields ? */
+        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 intfdata->send_setup(port);
+}
+EXPORT_SYMBOL(usb_wwan_tiocmset);
+
+/* Write */
+int usb_wwan_write(struct tty_struct *tty, struct usb_serial_port *port,
+                   const unsigned char *buf, int count)
+{
+        struct usb_wwan_port_private *portdata;
+        struct usb_wwan_intf_private *intfdata;
+        int i;
+        int left, todo;
+        struct urb *this_urb = NULL;    /* spurious */
+        int err;
+        unsigned long flags;
+
+        portdata = usb_get_serial_port_data(port);
+        intfdata = port->serial->private;
+
+        dbg("%s: write (%d chars)", __func__, count);
+
+        i = 0;
+        left = count;
+        for (i = 0; left > 0 && i < N_OUT_URB; i++) {
+                todo = left;
+                if (todo > OUT_BUFLEN)
+                        todo = OUT_BUFLEN;
+
+                this_urb = portdata->out_urbs[i];
+                if (test_and_set_bit(i, &portdata->out_busy)) {
+                        if (time_before(jiffies,
+                                        portdata->tx_start_time[i] + 10 * HZ))
+                                continue;
+                        usb_unlink_urb(this_urb);
+                        continue;
+                }
+                dbg("%s: endpoint %d buf %d", __func__,
+                    usb_pipeendpoint(this_urb->pipe), i);
+
+                err = usb_autopm_get_interface_async(port->serial->interface);
+                if (err < 0)
+                        break;
+
+                /* send the data */
+                memcpy(this_urb->transfer_buffer, buf, todo);
+                this_urb->transfer_buffer_length = todo;
+
+                spin_lock_irqsave(&intfdata->susp_lock, flags);
+                if (intfdata->suspended) {
+                        usb_anchor_urb(this_urb, &portdata->delayed);
+                        spin_unlock_irqrestore(&intfdata->susp_lock, flags);
+                } else {
+                        intfdata->in_flight++;
+                        spin_unlock_irqrestore(&intfdata->susp_lock, flags);
+                        err = usb_submit_urb(this_urb, GFP_ATOMIC);
+                        if (err) {
+                                dbg("usb_submit_urb %p (write bulk) failed "
+                                    "(%d)", this_urb, err);
+                                clear_bit(i, &portdata->out_busy);
+                                spin_lock_irqsave(&intfdata->susp_lock, flags);
+                                intfdata->in_flight--;
+                                spin_unlock_irqrestore(&intfdata->susp_lock,
+                                                       flags);
+                                continue;
+                        }
+                }
+
+                portdata->tx_start_time[i] = jiffies;
+                buf += todo;
+                left -= todo;
+        }
+
+        count -= left;
+        dbg("%s: wrote (did %d)", __func__, count);
+        return count;
+}
+EXPORT_SYMBOL(usb_wwan_write);
+
+static void usb_wwan_indat_callback(struct urb *urb)
+{
+        int err;
+        int endpoint;
+        struct usb_serial_port *port;
+        struct tty_struct *tty;
+        unsigned char *data = urb->transfer_buffer;
+        int status = urb->status;
+
+        dbg("%s: %p", __func__, urb);
+
+        endpoint = usb_pipeendpoint(urb->pipe);
+        port = urb->context;
+
+        if (status) {
+                dbg("%s: nonzero status: %d on endpoint %02x.",
+                    __func__, status, endpoint);
+        } else {
+                tty = tty_port_tty_get(&port->port);
+                if (urb->actual_length) {
+                        tty_insert_flip_string(tty, data, urb->actual_length);
+                        tty_flip_buffer_push(tty);
+                } else
+                        dbg("%s: empty read urb received", __func__);
+                tty_kref_put(tty);
+
+                /* Resubmit urb so we continue receiving */
+                if (status != -ESHUTDOWN) {
+                        err = usb_submit_urb(urb, GFP_ATOMIC);
+                        if (err && err != -EPERM)
+                                printk(KERN_ERR "%s: resubmit read urb failed. "
+                                       "(%d)", __func__, err);
+                        else
+                                usb_mark_last_busy(port->serial->dev);
+                }
+
+        }
+        return;
+}
+
+static void usb_wwan_outdat_callback(struct urb *urb)
+{
+        struct usb_serial_port *port;
+        struct usb_wwan_port_private *portdata;
+        struct usb_wwan_intf_private *intfdata;
+        int i;
+
+        dbg("%s", __func__);
+
+        port = urb->context;
+        intfdata = port->serial->private;
+
+        usb_serial_port_softint(port);
+        usb_autopm_put_interface_async(port->serial->interface);
+        portdata = usb_get_serial_port_data(port);
+        spin_lock(&intfdata->susp_lock);
+        intfdata->in_flight--;
+        spin_unlock(&intfdata->susp_lock);
+
+        for (i = 0; i < N_OUT_URB; ++i) {
+                if (portdata->out_urbs[i] == urb) {
+                        smp_mb__before_clear_bit();
+                        clear_bit(i, &portdata->out_busy);
+                        break;
+                }
+        }
+}
+
+int usb_wwan_write_room(struct tty_struct *tty)
+{
+        struct usb_serial_port *port = tty->driver_data;
+        struct usb_wwan_port_private *portdata;
+        int i;
+        int data_len = 0;
+        struct urb *this_urb;
+
+        portdata = usb_get_serial_port_data(port);
+
+        for (i = 0; i < N_OUT_URB; i++) {
+                this_urb = portdata->out_urbs[i];
+                if (this_urb && !test_bit(i, &portdata->out_busy))
+                        data_len += OUT_BUFLEN;
+        }
+
+        dbg("%s: %d", __func__, data_len);
+        return data_len;
+}
+EXPORT_SYMBOL(usb_wwan_write_room);
+
+int usb_wwan_chars_in_buffer(struct tty_struct *tty)
+{
+        struct usb_serial_port *port = tty->driver_data;
+        struct usb_wwan_port_private *portdata;
+        int i;
+        int data_len = 0;
+        struct urb *this_urb;
+
+        portdata = usb_get_serial_port_data(port);
+
+        for (i = 0; i < N_OUT_URB; i++) {
+                this_urb = portdata->out_urbs[i];
+                /* FIXME: This locking is insufficient as this_urb may
+                   go unused during the test */
+                if (this_urb && test_bit(i, &portdata->out_busy))
+                        data_len += this_urb->transfer_buffer_length;
+        }
+        dbg("%s: %d", __func__, data_len);
+        return data_len;
+}
+EXPORT_SYMBOL(usb_wwan_chars_in_buffer);
+
+int usb_wwan_open(struct tty_struct *tty, struct usb_serial_port *port)
+{
+        struct usb_wwan_port_private *portdata;
+        struct usb_wwan_intf_private *intfdata;
+        struct usb_serial *serial = port->serial;
+        int i, err;
+        struct urb *urb;
+
+        portdata = usb_get_serial_port_data(port);
+        intfdata = serial->private;
+
+        dbg("%s", __func__);
+
+        /* Start reading from the IN endpoint */
+        for (i = 0; i < N_IN_URB; i++) {
+                urb = portdata->in_urbs[i];
+                if (!urb)
+                        continue;
+                err = usb_submit_urb(urb, GFP_KERNEL);
+                if (err) {
+                        dbg("%s: submit urb %d failed (%d) %d",
+                            __func__, i, err, urb->transfer_buffer_length);
+                }
+        }
+
+        if (intfdata->send_setup)
+                intfdata->send_setup(port);
+
+        serial->interface->needs_remote_wakeup = 1;
+        spin_lock_irq(&intfdata->susp_lock);
+        portdata->opened = 1;
+        spin_unlock_irq(&intfdata->susp_lock);
+        usb_autopm_put_interface(serial->interface);
+
+        return 0;
+}
+EXPORT_SYMBOL(usb_wwan_open);
+
+void usb_wwan_close(struct usb_serial_port *port)
+{
+        int i;
+        struct usb_serial *serial = port->serial;
+        struct usb_wwan_port_private *portdata;
+        struct usb_wwan_intf_private *intfdata = port->serial->private;
+
+        dbg("%s", __func__);
+        portdata = usb_get_serial_port_data(port);
+
+        if (serial->dev) {
+                /* Stop reading/writing urbs */
+                spin_lock_irq(&intfdata->susp_lock);
+                portdata->opened = 0;
+                spin_unlock_irq(&intfdata->susp_lock);
+
+                for (i = 0; i < N_IN_URB; i++)
+                        usb_kill_urb(portdata->in_urbs[i]);
+                for (i = 0; i < N_OUT_URB; i++)
+                        usb_kill_urb(portdata->out_urbs[i]);
+                usb_autopm_get_interface(serial->interface);
+                serial->interface->needs_remote_wakeup = 0;
+        }
+}
+EXPORT_SYMBOL(usb_wwan_close);
+
+/* Helper functions used by usb_wwan_setup_urbs */
+static struct urb *usb_wwan_setup_urb(struct usb_serial *serial, int endpoint,
+                                      int dir, void *ctx, char *buf, int len,
+                                      void (*callback) (struct urb *))
+{
+        struct urb *urb;
+
+        if (endpoint == -1)
+                return NULL;    /* endpoint not needed */
+
+        urb = usb_alloc_urb(0, GFP_KERNEL);     /* No ISO */
+        if (urb == NULL) {
+                dbg("%s: alloc for endpoint %d failed.", __func__, endpoint);
+                return NULL;
+        }
+
+        /* Fill URB using supplied data. */
+        usb_fill_bulk_urb(urb, serial->dev,
+                          usb_sndbulkpipe(serial->dev, endpoint) | dir,
+                          buf, len, callback, ctx);
+
+        return urb;
+}
+
+/* Setup urbs */
+static void usb_wwan_setup_urbs(struct usb_serial *serial)
+{
+        int i, j;
+        struct usb_serial_port *port;
+        struct usb_wwan_port_private *portdata;
+
+        dbg("%s", __func__);
+
+        for (i = 0; i < serial->num_ports; i++) {
+                port = serial->port[i];
+                portdata = usb_get_serial_port_data(port);
+
+                /* Do indat endpoints first */
+                for (j = 0; j < N_IN_URB; ++j) {
+                        portdata->in_urbs[j] = usb_wwan_setup_urb(serial,
+                                                                  port->
+                                                                  bulk_in_endpointAddress,
+                                                                  USB_DIR_IN,
+                                                                  port,
+                                                                  portdata->
+                                                                  in_buffer[j],
+                                                                  IN_BUFLEN,
+                                                                  usb_wwan_indat_callback);
+                }
+
+                /* outdat endpoints */
+                for (j = 0; j < N_OUT_URB; ++j) {
+                        portdata->out_urbs[j] = usb_wwan_setup_urb(serial,
+                                                                   port->
+                                                                   bulk_out_endpointAddress,
+                                                                   USB_DIR_OUT,
+                                                                   port,
+                                                                   portdata->
+                                                                   out_buffer
+                                                                   [j],
+                                                                   OUT_BUFLEN,
+                                                                   usb_wwan_outdat_callback);
+                }
+        }
+}
+
+int usb_wwan_startup(struct usb_serial *serial)
+{
+        int i, j, err;
+        struct usb_serial_port *port;
+        struct usb_wwan_port_private *portdata;
+        u8 *buffer;
+
+        dbg("%s", __func__);
+
+        /* Now setup per port private data */
+        for (i = 0; i < serial->num_ports; i++) {
+                port = serial->port[i];
+                portdata = kzalloc(sizeof(*portdata), GFP_KERNEL);
+                if (!portdata) {
+                        dbg("%s: kmalloc for usb_wwan_port_private (%d) failed!.",
+                            __func__, i);
+                        return 1;
+                }
+                init_usb_anchor(&portdata->delayed);
+
+                for (j = 0; j < N_IN_URB; j++) {
+                        buffer = (u8 *) __get_free_page(GFP_KERNEL);
+                        if (!buffer)
+                                goto bail_out_error;
+                        portdata->in_buffer[j] = buffer;
+                }
+
+                for (j = 0; j < N_OUT_URB; j++) {
+                        buffer = kmalloc(OUT_BUFLEN, GFP_KERNEL);
+                        if (!buffer)
+                                goto bail_out_error2;
+                        portdata->out_buffer[j] = buffer;
+                }
+
+                usb_set_serial_port_data(port, portdata);
+
+                if (!port->interrupt_in_urb)
+                        continue;
+                err = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
+                if (err)
+                        dbg("%s: submit irq_in urb failed %d", __func__, err);
+        }
+        usb_wwan_setup_urbs(serial);
+        return 0;
+
+bail_out_error2:
+        for (j = 0; j < N_OUT_URB; j++)
+                kfree(portdata->out_buffer[j]);
+bail_out_error:
+        for (j = 0; j < N_IN_URB; j++)
+                if (portdata->in_buffer[j])
+                        free_page((unsigned long)portdata->in_buffer[j]);
+        kfree(portdata);
+        return 1;
+}
+EXPORT_SYMBOL(usb_wwan_startup);
+
+static void stop_read_write_urbs(struct usb_serial *serial)
+{
+        int i, j;
+        struct usb_serial_port *port;
+        struct usb_wwan_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);
+                for (j = 0; j < N_IN_URB; j++)
+                        usb_kill_urb(portdata->in_urbs[j]);
+                for (j = 0; j < N_OUT_URB; j++)
+                        usb_kill_urb(portdata->out_urbs[j]);
+        }
+}
+
+void usb_wwan_disconnect(struct usb_serial *serial)
+{
+        dbg("%s", __func__);
+
+        stop_read_write_urbs(serial);
+}
+EXPORT_SYMBOL(usb_wwan_disconnect);
+
+void usb_wwan_release(struct usb_serial *serial)
+{
+        int i, j;
+        struct usb_serial_port *port;
+        struct usb_wwan_port_private *portdata;
+
+        dbg("%s", __func__);
+
+        /* Now free them */
+        for (i = 0; i < serial->num_ports; ++i) {
+                port = serial->port[i];
+                portdata = usb_get_serial_port_data(port);
+
+                for (j = 0; j < N_IN_URB; j++) {
+                        usb_free_urb(portdata->in_urbs[j]);
+                        free_page((unsigned long)
+                                  portdata->in_buffer[j]);
+                        portdata->in_urbs[j] = NULL;
+                }
+                for (j = 0; j < N_OUT_URB; j++) {
+                        usb_free_urb(portdata->out_urbs[j]);
+                        kfree(portdata->out_buffer[j]);
+                        portdata->out_urbs[j] = NULL;
+                }
+        }
+
+        /* Now free per port private data */
+        for (i = 0; i < serial->num_ports; i++) {
+                port = serial->port[i];
+                kfree(usb_get_serial_port_data(port));
+        }
+}
+EXPORT_SYMBOL(usb_wwan_release);
+
+#ifdef CONFIG_PM
+int usb_wwan_suspend(struct usb_serial *serial, pm_message_t message)
+{
+        struct usb_wwan_intf_private *intfdata = serial->private;
+        int b;
+
+        dbg("%s entered", __func__);
+
+        if (message.event & PM_EVENT_AUTO) {
+                spin_lock_irq(&intfdata->susp_lock);
+                b = intfdata->in_flight;
+                spin_unlock_irq(&intfdata->susp_lock);
+
+                if (b)
+                        return -EBUSY;
+        }
+
+        spin_lock_irq(&intfdata->susp_lock);
+        intfdata->suspended = 1;
+        spin_unlock_irq(&intfdata->susp_lock);
+        stop_read_write_urbs(serial);
+
+        return 0;
+}
+EXPORT_SYMBOL(usb_wwan_suspend);
+
+static void play_delayed(struct usb_serial_port *port)
+{
+        struct usb_wwan_intf_private *data;
+        struct usb_wwan_port_private *portdata;
+        struct urb *urb;
+        int err;
+
+        portdata = usb_get_serial_port_data(port);
+        data = port->serial->private;
+        while ((urb = usb_get_from_anchor(&portdata->delayed))) {
+                err = usb_submit_urb(urb, GFP_ATOMIC);
+                if (!err)
+                        data->in_flight++;
+        }
+}
+
+int usb_wwan_resume(struct usb_serial *serial)
+{
+        int i, j;
+        struct usb_serial_port *port;
+        struct usb_wwan_intf_private *intfdata = serial->private;
+        struct usb_wwan_port_private *portdata;
+        struct urb *urb;
+        int err = 0;
+
+        dbg("%s entered", __func__);
+        /* get the interrupt URBs resubmitted unconditionally */
+        for (i = 0; i < serial->num_ports; i++) {
+                port = serial->port[i];
+                if (!port->interrupt_in_urb) {
+                        dbg("%s: No interrupt URB for port %d", __func__, i);
+                        continue;
+                }
+                err = usb_submit_urb(port->interrupt_in_urb, GFP_NOIO);
+                dbg("Submitted interrupt URB for port %d (result %d)", i, err);
+                if (err < 0) {
+                        err("%s: Error %d for interrupt URB of port%d",
+                            __func__, err, i);
+                        goto err_out;
+                }
+        }
+
+        for (i = 0; i < serial->num_ports; i++) {
+                /* walk all ports */
+                port = serial->port[i];
+                portdata = usb_get_serial_port_data(port);
+
+                /* skip closed ports */
+                spin_lock_irq(&intfdata->susp_lock);
+                if (!portdata->opened) {
+                        spin_unlock_irq(&intfdata->susp_lock);
+                        continue;
+                }
+
+                for (j = 0; j < N_IN_URB; j++) {
+                        urb = portdata->in_urbs[j];
+                        err = usb_submit_urb(urb, GFP_ATOMIC);
+                        if (err < 0) {
+                                err("%s: Error %d for bulk URB %d",
+                                    __func__, err, i);
+                                spin_unlock_irq(&intfdata->susp_lock);
+                                goto err_out;
+                        }
+                }
+                play_delayed(port);
+                spin_unlock_irq(&intfdata->susp_lock);
+        }
+        spin_lock_irq(&intfdata->susp_lock);
+        intfdata->suspended = 0;
+        spin_unlock_irq(&intfdata->susp_lock);
+err_out:
+        return err;
+}
+EXPORT_SYMBOL(usb_wwan_resume);
+#endif
+
+MODULE_AUTHOR(DRIVER_AUTHOR);
+MODULE_DESCRIPTION(DRIVER_DESC);
+MODULE_VERSION(DRIVER_VERSION);
+MODULE_LICENSE("GPL");
+
+module_param(debug, bool, S_IRUGO | S_IWUSR);
+MODULE_PARM_DESC(debug, "Debug messages");