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 5f777c20f2e..e399efdb91e 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 3203614e389..e54c728c016 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 00000000000..2be298a1305
--- /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 00000000000..0c70b4a621b
--- /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");