Linux-2.6.12-rc2v2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 942 insertions, 0 deletions

diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c
new file mode 100644
index 0000000..6d1f9b6
--- /dev/null
+++ b/drivers/usb/class/cdc-acm.c
@@ -0,0 +1,942 @@
+/*
+ * cdc-acm.c
+ *
+ * Copyright (c) 1999 Armin Fuerst	<fuerst@in.tum.de>
+ * Copyright (c) 1999 Pavel Machek	<pavel@suse.cz>
+ * Copyright (c) 1999 Johannes Erdfelt	<johannes@erdfelt.com>
+ * Copyright (c) 2000 Vojtech Pavlik	<vojtech@suse.cz>
+ * Copyright (c) 2004 Oliver Neukum	<oliver@neukum.name>
+ *
+ * USB Abstract Control Model driver for USB modems and ISDN adapters
+ *
+ * Sponsored by SuSE
+ *
+ * ChangeLog:
+ *	v0.9  - thorough cleaning, URBification, almost a rewrite
+ *	v0.10 - some more cleanups
+ *	v0.11 - fixed flow control, read error doesn't stop reads
+ *	v0.12 - added TIOCM ioctls, added break handling, made struct acm kmalloced
+ *	v0.13 - added termios, added hangup
+ *	v0.14 - sized down struct acm
+ *	v0.15 - fixed flow control again - characters could be lost
+ *	v0.16 - added code for modems with swapped data and control interfaces
+ *	v0.17 - added new style probing
+ *	v0.18 - fixed new style probing for devices with more configurations
+ *	v0.19 - fixed CLOCAL handling (thanks to Richard Shih-Ping Chan)
+ *	v0.20 - switched to probing on interface (rather than device) class
+ *	v0.21 - revert to probing on device for devices with multiple configs
+ *	v0.22 - probe only the control interface. if usbcore doesn't choose the
+ *		config we want, sysadmin changes bConfigurationValue in sysfs.
+ *	v0.23 - use softirq for rx processing, as needed by tty layer
+ *	v0.24 - change probe method to evaluate CDC union descriptor
+ */
+
+/*
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#undef DEBUG
+
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/tty.h>
+#include <linux/tty_driver.h>
+#include <linux/tty_flip.h>
+#include <linux/module.h>
+#include <linux/smp_lock.h>
+#include <asm/uaccess.h>
+#include <linux/usb.h>
+#include <linux/usb_cdc.h>
+#include <asm/byteorder.h>
+#include <asm/unaligned.h>
+
+#include "cdc-acm.h"
+
+/*
+ * Version Information
+ */
+#define DRIVER_VERSION "v0.23"
+#define DRIVER_AUTHOR "Armin Fuerst, Pavel Machek, Johannes Erdfelt, Vojtech Pavlik"
+#define DRIVER_DESC "USB Abstract Control Model driver for USB modems and ISDN adapters"
+
+static struct usb_driver acm_driver;
+static struct tty_driver *acm_tty_driver;
+static struct acm *acm_table[ACM_TTY_MINORS];
+
+static DECLARE_MUTEX(open_sem);
+
+#define ACM_READY(acm)	(acm && acm->dev && acm->used)
+
+/*
+ * Functions for ACM control messages.
+ */
+
+static int acm_ctrl_msg(struct acm *acm, int request, int value, void *buf, int len)
+{
+	int retval = usb_control_msg(acm->dev, usb_sndctrlpipe(acm->dev, 0),
+		request, USB_RT_ACM, value,
+		acm->control->altsetting[0].desc.bInterfaceNumber,
+		buf, len, 5000);
+	dbg("acm_control_msg: rq: 0x%02x val: %#x len: %#x result: %d", request, value, len, retval);
+	return retval < 0 ? retval : 0;
+}
+
+/* devices aren't required to support these requests.
+ * the cdc acm descriptor tells whether they do...
+ */
+#define acm_set_control(acm, control) \
+	acm_ctrl_msg(acm, USB_CDC_REQ_SET_CONTROL_LINE_STATE, control, NULL, 0)
+#define acm_set_line(acm, line) \
+	acm_ctrl_msg(acm, USB_CDC_REQ_SET_LINE_CODING, 0, line, sizeof *(line))
+#define acm_send_break(acm, ms) \
+	acm_ctrl_msg(acm, USB_CDC_REQ_SEND_BREAK, ms, NULL, 0)
+
+/*
+ * Interrupt handlers for various ACM device responses
+ */
+
+/* control interface reports status changes with "interrupt" transfers */
+static void acm_ctrl_irq(struct urb *urb, struct pt_regs *regs)
+{
+	struct acm *acm = urb->context;
+	struct usb_cdc_notification *dr = urb->transfer_buffer;
+	unsigned char *data;
+	int newctrl;
+	int status;
+
+	switch (urb->status) {
+	case 0:
+		/* success */
+		break;
+	case -ECONNRESET:
+	case -ENOENT:
+	case -ESHUTDOWN:
+		/* this urb is terminated, clean up */
+		dbg("%s - urb shutting down with status: %d", __FUNCTION__, urb->status);
+		return;
+	default:
+		dbg("%s - nonzero urb status received: %d", __FUNCTION__, urb->status);
+		goto exit;
+	}
+
+	if (!ACM_READY(acm))
+		goto exit;
+
+	data = (unsigned char *)(dr + 1);
+	switch (dr->bNotificationType) {
+
+		case USB_CDC_NOTIFY_NETWORK_CONNECTION:
+
+			dbg("%s network", dr->wValue ? "connected to" : "disconnected from");
+			break;
+
+		case USB_CDC_NOTIFY_SERIAL_STATE:
+
+			newctrl = le16_to_cpu(get_unaligned((__le16 *) data));
+
+			if (acm->tty && !acm->clocal && (acm->ctrlin & ~newctrl & ACM_CTRL_DCD)) {
+				dbg("calling hangup");
+				tty_hangup(acm->tty);
+			}
+
+			acm->ctrlin = newctrl;
+
+			dbg("input control lines: dcd%c dsr%c break%c ring%c framing%c parity%c overrun%c",
+				acm->ctrlin & ACM_CTRL_DCD ? '+' : '-',	acm->ctrlin & ACM_CTRL_DSR ? '+' : '-',
+				acm->ctrlin & ACM_CTRL_BRK ? '+' : '-',	acm->ctrlin & ACM_CTRL_RI  ? '+' : '-',
+				acm->ctrlin & ACM_CTRL_FRAMING ? '+' : '-',	acm->ctrlin & ACM_CTRL_PARITY ? '+' : '-',
+				acm->ctrlin & ACM_CTRL_OVERRUN ? '+' : '-');
+
+			break;
+
+		default:
+			dbg("unknown notification %d received: index %d len %d data0 %d data1 %d",
+				dr->bNotificationType, dr->wIndex,
+				dr->wLength, data[0], data[1]);
+			break;
+	}
+exit:
+	status = usb_submit_urb (urb, GFP_ATOMIC);
+	if (status)
+		err ("%s - usb_submit_urb failed with result %d",
+		     __FUNCTION__, status);
+}
+
+/* data interface returns incoming bytes, or we got unthrottled */
+static void acm_read_bulk(struct urb *urb, struct pt_regs *regs)
+{
+	struct acm *acm = urb->context;
+	dbg("Entering acm_read_bulk with status %d\n", urb->status);
+
+	if (!ACM_READY(acm))
+		return;
+
+	if (urb->status)
+		dev_dbg(&acm->data->dev, "bulk rx status %d\n", urb->status);
+
+	/* calling tty_flip_buffer_push() in_irq() isn't allowed */
+	tasklet_schedule(&acm->bh);
+}
+
+static void acm_rx_tasklet(unsigned long _acm)
+{
+	struct acm *acm = (void *)_acm;
+	struct urb *urb = acm->readurb;
+	struct tty_struct *tty = acm->tty;
+	unsigned char *data = urb->transfer_buffer;
+	int i = 0;
+	dbg("Entering acm_rx_tasklet");
+
+	if (urb->actual_length > 0 && !acm->throttle)  {
+		for (i = 0; i < urb->actual_length && !acm->throttle; i++) {
+			/* if we insert more than TTY_FLIPBUF_SIZE characters,
+			 * we drop them. */
+			if (tty->flip.count >= TTY_FLIPBUF_SIZE) {
+				tty_flip_buffer_push(tty);
+			}
+			tty_insert_flip_char(tty, data[i], 0);
+		}
+		dbg("Handed %d bytes to tty layer", i+1);
+		tty_flip_buffer_push(tty);
+	}
+
+	spin_lock(&acm->throttle_lock);
+	if (acm->throttle) {
+		dbg("Throtteling noticed");
+		memmove(data, data + i, urb->actual_length - i);
+		urb->actual_length -= i;
+		acm->resubmit_to_unthrottle = 1;
+		spin_unlock(&acm->throttle_lock);
+		return;
+	}
+	spin_unlock(&acm->throttle_lock);
+
+	urb->actual_length = 0;
+	urb->dev = acm->dev;
+
+	i = usb_submit_urb(urb, GFP_ATOMIC);
+	if (i)
+		dev_dbg(&acm->data->dev, "bulk rx resubmit %d\n", i);
+}
+
+/* data interface wrote those outgoing bytes */
+static void acm_write_bulk(struct urb *urb, struct pt_regs *regs)
+{
+	struct acm *acm = (struct acm *)urb->context;
+	dbg("Entering acm_write_bulk with status %d\n", urb->status);
+
+	if (!ACM_READY(acm))
+		goto out;
+
+	if (urb->status)
+		dbg("nonzero write bulk status received: %d", urb->status);
+
+	schedule_work(&acm->work);
+out:
+	acm->ready_for_write = 1;
+}
+
+static void acm_softint(void *private)
+{
+	struct acm *acm = private;
+	dbg("Entering acm_softint.\n");
+	
+	if (!ACM_READY(acm))
+		return;
+	tty_wakeup(acm->tty);
+}
+
+/*
+ * TTY handlers
+ */
+
+static int acm_tty_open(struct tty_struct *tty, struct file *filp)
+{
+	struct acm *acm;
+	int rv = -EINVAL;
+	dbg("Entering acm_tty_open.\n");
+	
+	down(&open_sem);
+
+	acm = acm_table[tty->index];
+	if (!acm || !acm->dev)
+		goto err_out;
+	else
+		rv = 0;
+
+	tty->driver_data = acm;
+	acm->tty = tty;
+
+
+
+	if (acm->used++) {
+		goto done;
+        }
+
+	acm->ctrlurb->dev = acm->dev;
+	if (usb_submit_urb(acm->ctrlurb, GFP_KERNEL)) {
+		dbg("usb_submit_urb(ctrl irq) failed");
+		goto bail_out;
+	}
+
+	acm->readurb->dev = acm->dev;
+	if (usb_submit_urb(acm->readurb, GFP_KERNEL)) {
+		dbg("usb_submit_urb(read bulk) failed");
+		goto bail_out_and_unlink;
+	}
+
+	if (0 > acm_set_control(acm, acm->ctrlout = ACM_CTRL_DTR | ACM_CTRL_RTS))
+		goto full_bailout;
+
+	/* force low_latency on so that our tty_push actually forces the data through, 
+	   otherwise it is scheduled, and with high data rates data can get lost. */
+	tty->low_latency = 1;
+
+done:
+err_out:
+	up(&open_sem);
+	return rv;
+
+full_bailout:
+	usb_kill_urb(acm->readurb);
+bail_out_and_unlink:
+	usb_kill_urb(acm->ctrlurb);
+bail_out:
+	acm->used--;
+	up(&open_sem);
+	return -EIO;
+}
+
+static void acm_tty_close(struct tty_struct *tty, struct file *filp)
+{
+	struct acm *acm = tty->driver_data;
+
+	if (!acm || !acm->used)
+		return;
+
+	down(&open_sem);
+	if (!--acm->used) {
+		if (acm->dev) {
+			acm_set_control(acm, acm->ctrlout = 0);
+			usb_kill_urb(acm->ctrlurb);
+			usb_kill_urb(acm->writeurb);
+			usb_kill_urb(acm->readurb);
+		} else {
+			tty_unregister_device(acm_tty_driver, acm->minor);
+			acm_table[acm->minor] = NULL;
+			usb_free_urb(acm->ctrlurb);
+			usb_free_urb(acm->readurb);
+			usb_free_urb(acm->writeurb);
+			kfree(acm);
+		}
+	}
+	up(&open_sem);
+}
+
+static int acm_tty_write(struct tty_struct *tty, const unsigned char *buf, int count)
+{
+	struct acm *acm = tty->driver_data;
+	int stat;
+	dbg("Entering acm_tty_write to write %d bytes,\n", count);
+
+	if (!ACM_READY(acm))
+		return -EINVAL;
+	if (!acm->ready_for_write)
+		return 0;
+	if (!count)
+		return 0;
+
+	count = (count > acm->writesize) ? acm->writesize : count;
+
+	dbg("Get %d bytes...", count);
+	memcpy(acm->write_buffer, buf, count);
+	dbg("  Successfully copied.\n");
+
+	acm->writeurb->transfer_buffer_length = count;
+	acm->writeurb->dev = acm->dev;
+
+	acm->ready_for_write = 0;
+	stat = usb_submit_urb(acm->writeurb, GFP_ATOMIC);
+	if (stat < 0) {
+		dbg("usb_submit_urb(write bulk) failed");
+		acm->ready_for_write = 1;
+		return stat;
+	}
+
+	return count;
+}
+
+static int acm_tty_write_room(struct tty_struct *tty)
+{
+	struct acm *acm = tty->driver_data;
+	if (!ACM_READY(acm))
+		return -EINVAL;
+	return !acm->ready_for_write ? 0 : acm->writesize;
+}
+
+static int acm_tty_chars_in_buffer(struct tty_struct *tty)
+{
+	struct acm *acm = tty->driver_data;
+	if (!ACM_READY(acm))
+		return -EINVAL;
+	return !acm->ready_for_write ? acm->writeurb->transfer_buffer_length : 0;
+}
+
+static void acm_tty_throttle(struct tty_struct *tty)
+{
+	struct acm *acm = tty->driver_data;
+	if (!ACM_READY(acm))
+		return;
+	spin_lock_bh(&acm->throttle_lock);
+	acm->throttle = 1;
+	spin_unlock_bh(&acm->throttle_lock);
+}
+
+static void acm_tty_unthrottle(struct tty_struct *tty)
+{
+	struct acm *acm = tty->driver_data;
+	if (!ACM_READY(acm))
+		return;
+	spin_lock_bh(&acm->throttle_lock);
+	acm->throttle = 0;
+	spin_unlock_bh(&acm->throttle_lock);
+	if (acm->resubmit_to_unthrottle) {
+		acm->resubmit_to_unthrottle = 0;
+		acm_read_bulk(acm->readurb, NULL);
+	}
+}
+
+static void acm_tty_break_ctl(struct tty_struct *tty, int state)
+{
+	struct acm *acm = tty->driver_data;
+	if (!ACM_READY(acm))
+		return;
+	if (acm_send_break(acm, state ? 0xffff : 0))
+		dbg("send break failed");
+}
+
+static int acm_tty_tiocmget(struct tty_struct *tty, struct file *file)
+{
+	struct acm *acm = tty->driver_data;
+
+	if (!ACM_READY(acm))
+		return -EINVAL;
+
+	return (acm->ctrlout & ACM_CTRL_DTR ? TIOCM_DTR : 0) |
+	       (acm->ctrlout & ACM_CTRL_RTS ? TIOCM_RTS : 0) |
+	       (acm->ctrlin  & ACM_CTRL_DSR ? TIOCM_DSR : 0) |
+	       (acm->ctrlin  & ACM_CTRL_RI  ? TIOCM_RI  : 0) |
+	       (acm->ctrlin  & ACM_CTRL_DCD ? TIOCM_CD  : 0) |
+	       TIOCM_CTS;
+}
+
+static int acm_tty_tiocmset(struct tty_struct *tty, struct file *file,
+			    unsigned int set, unsigned int clear)
+{
+	struct acm *acm = tty->driver_data;
+	unsigned int newctrl;
+
+	if (!ACM_READY(acm))
+		return -EINVAL;
+
+	newctrl = acm->ctrlout;
+	set = (set & TIOCM_DTR ? ACM_CTRL_DTR : 0) | (set & TIOCM_RTS ? ACM_CTRL_RTS : 0);
+	clear = (clear & TIOCM_DTR ? ACM_CTRL_DTR : 0) | (clear & TIOCM_RTS ? ACM_CTRL_RTS : 0);
+
+	newctrl = (newctrl & ~clear) | set;
+
+	if (acm->ctrlout == newctrl)
+		return 0;
+	return acm_set_control(acm, acm->ctrlout = newctrl);
+}
+
+static int acm_tty_ioctl(struct tty_struct *tty, struct file *file, unsigned int cmd, unsigned long arg)
+{
+	struct acm *acm = tty->driver_data;
+
+	if (!ACM_READY(acm))
+		return -EINVAL;
+
+	return -ENOIOCTLCMD;
+}
+
+static __u32 acm_tty_speed[] = {
+	0, 50, 75, 110, 134, 150, 200, 300, 600,
+	1200, 1800, 2400, 4800, 9600, 19200, 38400,
+	57600, 115200, 230400, 460800, 500000, 576000,
+	921600, 1000000, 1152000, 1500000, 2000000,
+	2500000, 3000000, 3500000, 4000000
+};
+
+static __u8 acm_tty_size[] = {
+	5, 6, 7, 8
+};
+
+static void acm_tty_set_termios(struct tty_struct *tty, struct termios *termios_old)
+{
+	struct acm *acm = tty->driver_data;
+	struct termios *termios = tty->termios;
+	struct usb_cdc_line_coding newline;
+	int newctrl = acm->ctrlout;
+
+	if (!ACM_READY(acm))
+		return;
+
+	newline.dwDTERate = cpu_to_le32p(acm_tty_speed +
+		(termios->c_cflag & CBAUD & ~CBAUDEX) + (termios->c_cflag & CBAUDEX ? 15 : 0));
+	newline.bCharFormat = termios->c_cflag & CSTOPB ? 2 : 0;
+	newline.bParityType = termios->c_cflag & PARENB ?
+		(termios->c_cflag & PARODD ? 1 : 2) + (termios->c_cflag & CMSPAR ? 2 : 0) : 0;
+	newline.bDataBits = acm_tty_size[(termios->c_cflag & CSIZE) >> 4];
+
+	acm->clocal = ((termios->c_cflag & CLOCAL) != 0);
+
+	if (!newline.dwDTERate) {
+		newline.dwDTERate = acm->line.dwDTERate;
+		newctrl &= ~ACM_CTRL_DTR;
+	} else  newctrl |=  ACM_CTRL_DTR;
+
+	if (newctrl != acm->ctrlout)
+		acm_set_control(acm, acm->ctrlout = newctrl);
+
+	if (memcmp(&acm->line, &newline, sizeof newline)) {
+		memcpy(&acm->line, &newline, sizeof newline);
+		dbg("set line: %d %d %d %d", le32_to_cpu(newline.dwDTERate),
+			newline.bCharFormat, newline.bParityType,
+			newline.bDataBits);
+		acm_set_line(acm, &acm->line);
+	}
+}
+
+/*
+ * USB probe and disconnect routines.
+ */
+
+static int acm_probe (struct usb_interface *intf,
+		      const struct usb_device_id *id)
+{
+	struct usb_cdc_union_desc *union_header = NULL;
+	char *buffer = intf->altsetting->extra;
+	int buflen = intf->altsetting->extralen;
+	struct usb_interface *control_interface;
+	struct usb_interface *data_interface;
+	struct usb_endpoint_descriptor *epctrl;
+	struct usb_endpoint_descriptor *epread;
+	struct usb_endpoint_descriptor *epwrite;
+	struct usb_device *usb_dev = interface_to_usbdev(intf);
+	struct acm *acm;
+	int minor;
+	int ctrlsize,readsize;
+	u8 *buf;
+	u8 ac_management_function = 0;
+	u8 call_management_function = 0;
+	int call_interface_num = -1;
+	int data_interface_num;
+	unsigned long quirks;
+
+	/* handle quirks deadly to normal probing*/
+	quirks = (unsigned long)id->driver_info;
+	if (quirks == NO_UNION_NORMAL) {
+		data_interface = usb_ifnum_to_if(usb_dev, 1);
+		control_interface = usb_ifnum_to_if(usb_dev, 0);
+		goto skip_normal_probe;
+	}
+	
+	/* normal probing*/
+	if (!buffer) {
+		err("Wierd descriptor references\n");
+		return -EINVAL;
+	}
+
+	if (!buflen) {
+		if (intf->cur_altsetting->endpoint->extralen && intf->cur_altsetting->endpoint->extra) {
+			dev_dbg(&intf->dev,"Seeking extra descriptors on endpoint\n");
+			buflen = intf->cur_altsetting->endpoint->extralen;
+			buffer = intf->cur_altsetting->endpoint->extra;
+		} else {
+			err("Zero length descriptor references\n");
+			return -EINVAL;
+		}
+	}
+
+	while (buflen > 0) {
+		if (buffer [1] != USB_DT_CS_INTERFACE) {
+			err("skipping garbage\n");
+			goto next_desc;
+		}
+
+		switch (buffer [2]) {
+			case USB_CDC_UNION_TYPE: /* we've found it */
+				if (union_header) {
+					err("More than one union descriptor, skipping ...");
+					goto next_desc;
+				}
+				union_header = (struct usb_cdc_union_desc *)
+							buffer;
+				break;
+			case USB_CDC_COUNTRY_TYPE: /* maybe somehow export */
+				break; /* for now we ignore it */
+			case USB_CDC_HEADER_TYPE: /* maybe check version */ 
+				break; /* for now we ignore it */ 
+			case USB_CDC_ACM_TYPE:
+				ac_management_function = buffer[3];
+				break;
+			case USB_CDC_CALL_MANAGEMENT_TYPE:
+				call_management_function = buffer[3];
+				call_interface_num = buffer[4];
+				if ((call_management_function & 3) != 3)
+					err("This device cannot do calls on its own. It is no modem.");
+				break;
+				
+			default:
+				err("Ignoring extra header, type %d, length %d", buffer[2], buffer[0]);
+				break;
+			}
+next_desc:
+		buflen -= buffer[0];
+		buffer += buffer[0];
+	}
+
+	if (!union_header) {
+		if (call_interface_num > 0) {
+			dev_dbg(&intf->dev,"No union descriptor, using call management descriptor\n");
+			data_interface = usb_ifnum_to_if(usb_dev, (data_interface_num = call_interface_num));
+			control_interface = intf;
+		} else {
+			dev_dbg(&intf->dev,"No union descriptor, giving up\n");
+			return -ENODEV;
+		}
+	} else {
+		control_interface = usb_ifnum_to_if(usb_dev, union_header->bMasterInterface0);
+		data_interface = usb_ifnum_to_if(usb_dev, (data_interface_num = union_header->bSlaveInterface0));
+		if (!control_interface || !data_interface) {
+			dev_dbg(&intf->dev,"no interfaces\n");
+			return -ENODEV;
+		}
+	}
+	
+	if (data_interface_num != call_interface_num)
+		dev_dbg(&intf->dev,"Seperate call control interface. That is not fully supported.\n");
+
+skip_normal_probe:
+
+	/*workaround for switched interfaces */
+	if (data_interface->cur_altsetting->desc.bInterfaceClass != CDC_DATA_INTERFACE_TYPE) {
+		if (control_interface->cur_altsetting->desc.bInterfaceClass == CDC_DATA_INTERFACE_TYPE) {
+			struct usb_interface *t;
+			dev_dbg(&intf->dev,"Your device has switched interfaces.\n");
+
+			t = control_interface;
+			control_interface = data_interface;
+			data_interface = t;
+		} else {
+			return -EINVAL;
+		}
+	}
+	
+	if (usb_interface_claimed(data_interface)) { /* valid in this context */
+		dev_dbg(&intf->dev,"The data interface isn't available\n");
+		return -EBUSY;
+	}
+
+
+	if (data_interface->cur_altsetting->desc.bNumEndpoints < 2)
+		return -EINVAL;
+
+	epctrl = &control_interface->cur_altsetting->endpoint[0].desc;
+	epread = &data_interface->cur_altsetting->endpoint[0].desc;
+	epwrite = &data_interface->cur_altsetting->endpoint[1].desc;
+
+
+	/* workaround for switched endpoints */
+	if ((epread->bEndpointAddress & USB_DIR_IN) != USB_DIR_IN) {
+		/* descriptors are swapped */
+		struct usb_endpoint_descriptor *t;
+		dev_dbg(&intf->dev,"The data interface has switched endpoints\n");
+		
+		t = epread;
+		epread = epwrite;
+		epwrite = t;
+	}
+	dbg("interfaces are valid");
+	for (minor = 0; minor < ACM_TTY_MINORS && acm_table[minor]; minor++);
+
+	if (minor == ACM_TTY_MINORS) {
+		err("no more free acm devices");
+		return -ENODEV;
+	}
+
+	if (!(acm = kmalloc(sizeof(struct acm), GFP_KERNEL))) {
+		dev_dbg(&intf->dev, "out of memory (acm kmalloc)\n");
+		goto alloc_fail;
+	}
+	memset(acm, 0, sizeof(struct acm));
+
+	ctrlsize = le16_to_cpu(epctrl->wMaxPacketSize);
+	readsize = le16_to_cpu(epread->wMaxPacketSize);
+	acm->writesize = le16_to_cpu(epwrite->wMaxPacketSize);
+	acm->control = control_interface;
+	acm->data = data_interface;
+	acm->minor = minor;
+	acm->dev = usb_dev;
+	acm->ctrl_caps = ac_management_function;
+	acm->ctrlsize = ctrlsize;
+	acm->readsize = readsize;
+	acm->bh.func = acm_rx_tasklet;
+	acm->bh.data = (unsigned long) acm;
+	INIT_WORK(&acm->work, acm_softint, acm);
+	spin_lock_init(&acm->throttle_lock);
+	acm->ready_for_write = 1;
+
+	buf = usb_buffer_alloc(usb_dev, ctrlsize, GFP_KERNEL, &acm->ctrl_dma);
+	if (!buf) {
+		dev_dbg(&intf->dev, "out of memory (ctrl buffer alloc)\n");
+		goto alloc_fail2;
+	}
+	acm->ctrl_buffer = buf;
+
+	buf = usb_buffer_alloc(usb_dev, readsize, GFP_KERNEL, &acm->read_dma);
+	if (!buf) {
+		dev_dbg(&intf->dev, "out of memory (read buffer alloc)\n");
+		goto alloc_fail3;
+	}
+	acm->read_buffer = buf;
+
+	buf = usb_buffer_alloc(usb_dev, acm->writesize, GFP_KERNEL, &acm->write_dma);
+	if (!buf) {
+		dev_dbg(&intf->dev, "out of memory (write buffer alloc)\n");
+		goto alloc_fail4;
+	}
+	acm->write_buffer = buf;	
+
+	acm->ctrlurb = usb_alloc_urb(0, GFP_KERNEL);
+	if (!acm->ctrlurb) {
+		dev_dbg(&intf->dev, "out of memory (ctrlurb kmalloc)\n");
+		goto alloc_fail5;
+	}
+	acm->readurb = usb_alloc_urb(0, GFP_KERNEL);
+	if (!acm->readurb) {
+		dev_dbg(&intf->dev, "out of memory (readurb kmalloc)\n");
+		goto alloc_fail6;
+	}
+	acm->writeurb = usb_alloc_urb(0, GFP_KERNEL);
+	if (!acm->writeurb) {
+		dev_dbg(&intf->dev, "out of memory (writeurb kmalloc)\n");
+		goto alloc_fail7;
+	}
+
+	usb_fill_int_urb(acm->ctrlurb, usb_dev, usb_rcvintpipe(usb_dev, epctrl->bEndpointAddress),
+			 acm->ctrl_buffer, ctrlsize, acm_ctrl_irq, acm, epctrl->bInterval);
+	acm->ctrlurb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
+	acm->ctrlurb->transfer_dma = acm->ctrl_dma;
+
+	usb_fill_bulk_urb(acm->readurb, usb_dev, usb_rcvbulkpipe(usb_dev, epread->bEndpointAddress),
+			  acm->read_buffer, readsize, acm_read_bulk, acm);
+	acm->readurb->transfer_flags |= URB_NO_FSBR | URB_NO_TRANSFER_DMA_MAP;
+	acm->readurb->transfer_dma = acm->read_dma;
+
+	usb_fill_bulk_urb(acm->writeurb, usb_dev, usb_sndbulkpipe(usb_dev, epwrite->bEndpointAddress),
+			  acm->write_buffer, acm->writesize, acm_write_bulk, acm);
+	acm->writeurb->transfer_flags |= URB_NO_FSBR | URB_NO_TRANSFER_DMA_MAP;
+	acm->writeurb->transfer_dma = acm->write_dma;
+
+	dev_info(&intf->dev, "ttyACM%d: USB ACM device\n", minor);
+
+	acm_set_control(acm, acm->ctrlout);
+
+	acm->line.dwDTERate = cpu_to_le32(9600);
+	acm->line.bDataBits = 8;
+	acm_set_line(acm, &acm->line);
+
+	usb_driver_claim_interface(&acm_driver, data_interface, acm);
+
+	tty_register_device(acm_tty_driver, minor, &intf->dev);
+
+	acm_table[minor] = acm;
+	usb_set_intfdata (intf, acm);
+	return 0;
+
+alloc_fail7:
+	usb_free_urb(acm->readurb);
+alloc_fail6:
+	usb_free_urb(acm->ctrlurb);
+alloc_fail5:
+	usb_buffer_free(usb_dev, acm->writesize, acm->write_buffer, acm->write_dma);
+alloc_fail4:
+	usb_buffer_free(usb_dev, readsize, acm->read_buffer, acm->read_dma);
+alloc_fail3:
+	usb_buffer_free(usb_dev, ctrlsize, acm->ctrl_buffer, acm->ctrl_dma);
+alloc_fail2:
+	kfree(acm);
+alloc_fail:
+	return -ENOMEM;
+}
+
+static void acm_disconnect(struct usb_interface *intf)
+{
+	struct acm *acm = usb_get_intfdata (intf);
+	struct usb_device *usb_dev = interface_to_usbdev(intf);
+
+	if (!acm || !acm->dev) {
+		dbg("disconnect on nonexisting interface");
+		return;
+	}
+
+	down(&open_sem);
+	acm->dev = NULL;
+	usb_set_intfdata (intf, NULL);
+
+	usb_kill_urb(acm->ctrlurb);
+	usb_kill_urb(acm->readurb);
+	usb_kill_urb(acm->writeurb);
+
+	flush_scheduled_work(); /* wait for acm_softint */
+
+	usb_buffer_free(usb_dev, acm->writesize, acm->write_buffer, acm->write_dma);
+	usb_buffer_free(usb_dev, acm->readsize, acm->read_buffer, acm->read_dma);
+	usb_buffer_free(usb_dev, acm->ctrlsize, acm->ctrl_buffer, acm->ctrl_dma);
+
+	usb_driver_release_interface(&acm_driver, acm->data);
+
+	if (!acm->used) {
+		tty_unregister_device(acm_tty_driver, acm->minor);
+		acm_table[acm->minor] = NULL;
+		usb_free_urb(acm->ctrlurb);
+		usb_free_urb(acm->readurb);
+		usb_free_urb(acm->writeurb);
+		kfree(acm);
+		up(&open_sem);
+		return;
+	}
+
+	up(&open_sem);
+
+	if (acm->tty)
+		tty_hangup(acm->tty);
+}
+
+/*
+ * USB driver structure.
+ */
+
+static struct usb_device_id acm_ids[] = {
+	/* quirky and broken devices */
+	{ USB_DEVICE(0x0870, 0x0001), /* Metricom GS Modem */
+	.driver_info = NO_UNION_NORMAL, /* has no union descriptor */
+	},
+	/* control interfaces with various AT-command sets */
+	{ USB_INTERFACE_INFO(USB_CLASS_COMM, USB_CDC_SUBCLASS_ACM,
+		USB_CDC_ACM_PROTO_AT_V25TER) },
+	{ USB_INTERFACE_INFO(USB_CLASS_COMM, USB_CDC_SUBCLASS_ACM,
+		USB_CDC_ACM_PROTO_AT_PCCA101) },
+	{ USB_INTERFACE_INFO(USB_CLASS_COMM, USB_CDC_SUBCLASS_ACM,
+		USB_CDC_ACM_PROTO_AT_PCCA101_WAKE) },
+	{ USB_INTERFACE_INFO(USB_CLASS_COMM, USB_CDC_SUBCLASS_ACM,
+		USB_CDC_ACM_PROTO_AT_GSM) },
+	{ USB_INTERFACE_INFO(USB_CLASS_COMM, USB_CDC_SUBCLASS_ACM,
+		USB_CDC_ACM_PROTO_AT_3G	) },
+	{ USB_INTERFACE_INFO(USB_CLASS_COMM, USB_CDC_SUBCLASS_ACM,
+		USB_CDC_ACM_PROTO_AT_CDMA) },
+
+	/* NOTE:  COMM/ACM/0xff is likely MSFT RNDIS ... NOT a modem!! */
+	{ }
+};
+
+MODULE_DEVICE_TABLE (usb, acm_ids);
+
+static struct usb_driver acm_driver = {
+	.owner =	THIS_MODULE,
+	.name =		"cdc_acm",
+	.probe =	acm_probe,
+	.disconnect =	acm_disconnect,
+	.id_table =	acm_ids,
+};
+
+/*
+ * TTY driver structures.
+ */
+
+static struct tty_operations acm_ops = {
+	.open =			acm_tty_open,
+	.close =		acm_tty_close,
+	.write =		acm_tty_write,
+	.write_room =		acm_tty_write_room,
+	.ioctl =		acm_tty_ioctl,
+	.throttle =		acm_tty_throttle,
+	.unthrottle =		acm_tty_unthrottle,
+	.chars_in_buffer =	acm_tty_chars_in_buffer,
+	.break_ctl =		acm_tty_break_ctl,
+	.set_termios =		acm_tty_set_termios,
+	.tiocmget =		acm_tty_tiocmget,
+	.tiocmset =		acm_tty_tiocmset,
+};
+
+/*
+ * Init / exit.
+ */
+
+static int __init acm_init(void)
+{
+	int retval;
+	acm_tty_driver = alloc_tty_driver(ACM_TTY_MINORS);
+	if (!acm_tty_driver)
+		return -ENOMEM;
+	acm_tty_driver->owner = THIS_MODULE,
+	acm_tty_driver->driver_name = "acm",
+	acm_tty_driver->name = "ttyACM",
+	acm_tty_driver->devfs_name = "usb/acm/",
+	acm_tty_driver->major = ACM_TTY_MAJOR,
+	acm_tty_driver->minor_start = 0,
+	acm_tty_driver->type = TTY_DRIVER_TYPE_SERIAL,
+	acm_tty_driver->subtype = SERIAL_TYPE_NORMAL,
+	acm_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_NO_DEVFS,
+	acm_tty_driver->init_termios = tty_std_termios;
+	acm_tty_driver->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL | CLOCAL;
+	tty_set_operations(acm_tty_driver, &acm_ops);
+
+	retval = tty_register_driver(acm_tty_driver);
+	if (retval) {
+		put_tty_driver(acm_tty_driver);
+		return retval;
+	}
+
+	retval = usb_register(&acm_driver);
+	if (retval) {
+		tty_unregister_driver(acm_tty_driver);
+		put_tty_driver(acm_tty_driver);
+		return retval;
+	}
+
+	info(DRIVER_VERSION ":" DRIVER_DESC);
+
+	return 0;
+}
+
+static void __exit acm_exit(void)
+{
+	usb_deregister(&acm_driver);
+	tty_unregister_driver(acm_tty_driver);
+	put_tty_driver(acm_tty_driver);
+}
+
+module_init(acm_init);
+module_exit(acm_exit);
+
+MODULE_AUTHOR( DRIVER_AUTHOR );
+MODULE_DESCRIPTION( DRIVER_DESC );
+MODULE_LICENSE("GPL");
+