usb serial: Add generic USB wwan support
authorMatthew Garrett <mjg@redhat.com>
Thu, 1 Apr 2010 16:31:07 +0000 (12:31 -0400)
committerGreg Kroah-Hartman <gregkh@suse.de>
Thu, 20 May 2010 20:21:37 +0000 (13:21 -0700)
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>
drivers/usb/serial/Kconfig
drivers/usb/serial/Makefile
drivers/usb/serial/usb-wwan.h [new file with mode: 0644]
drivers/usb/serial/usb_wwan.c [new file with mode: 0644]

index 5f777c2..e399efd 100644 (file)
@@ -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
index 3203614..e54c728 100644 (file)
@@ -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 (file)
index 0000000..2be298a
--- /dev/null
@@ -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 (file)
index 0000000..0c70b4a
--- /dev/null
@@ -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");