drivers/usb/serial/safe_serial.c - LeafOS-Devices/android_kernel_realme_mt6785 - Gitiles

 /*
  * Safe Encapsulated USB Serial Driver
  *
  *      Copyright (C) 2001 Lineo
  *      Copyright (C) 2001 Hewlett-Packard
  *
  *	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.
  *
  * By:
  *      Stuart Lynne <sl@lineo.com>, Tom Rushworth <tbr@lineo.com>
  */

 /*
  * The encapsultaion is designed to overcome difficulties with some USB hardware.
  *
  * While the USB protocol has a CRC over the data while in transit, i.e. while
  * being carried over the bus, there is no end to end protection. If the hardware
  * has any problems getting the data into or out of the USB transmit and receive
  * FIFO's then data can be lost.
  *
  * This protocol adds a two byte trailer to each USB packet to specify the number
  * of bytes of valid data and a 10 bit CRC that will allow the receiver to verify
  * that the entire USB packet was received without error.
  *
  * Because in this case the sender and receiver are the class and function drivers
  * there is now end to end protection.
  *
  * There is an additional option that can be used to force all transmitted packets
  * to be padded to the maximum packet size. This provides a work around for some
  * devices which have problems with small USB packets.
  *
  * Assuming a packetsize of N:
  *
  *      0..N-2  data and optional padding
  *
  *      N-2     bits 7-2 - number of bytes of valid data
  *              bits 1-0 top two bits of 10 bit CRC
  *      N-1     bottom 8 bits of 10 bit CRC
  *
  *
  *      | Data Length       | 10 bit CRC                                |
  *      + 7 . 6 . 5 . 4 . 3 . 2 . 1 . 0 | 7 . 6 . 5 . 4 . 3 . 2 . 1 . 0 +
  *
  * The 10 bit CRC is computed across the sent data, followed by the trailer with
  * the length set and the CRC set to zero. The CRC is then OR'd into the trailer.
  *
  * When received a 10 bit CRC is computed over the entire frame including the trailer
  * and should be equal to zero.
  *
  * Two module parameters are used to control the encapsulation, if both are
  * turned of the module works as a simple serial device with NO
  * encapsulation.
  *
  * See linux/drivers/usbd/serial_fd for a device function driver
  * implementation of this.
  *
  */


 #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/spinlock.h>
 #include <asm/uaccess.h>
 #include <linux/usb.h>
 #include <linux/usb/serial.h>


 #ifndef CONFIG_USB_SAFE_PADDED
 #define CONFIG_USB_SAFE_PADDED 0
 #endif

 static int debug;
 static int safe = 1;
 static int padded = CONFIG_USB_SAFE_PADDED;

 #define DRIVER_VERSION "v0.0b"
 #define DRIVER_AUTHOR "sl@lineo.com, tbr@lineo.com"
 #define DRIVER_DESC "USB Safe Encapsulated Serial"

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

 #if defined(CONFIG_USBD_SAFE_SERIAL_VENDOR) && !defined(CONFIG_USBD_SAFE_SERIAL_PRODUCT)
 #error "SAFE_SERIAL_VENDOR defined without SAFE_SERIAL_PRODUCT"
 #endif

 #if ! defined(CONFIG_USBD_SAFE_SERIAL_VENDOR)
 static __u16 vendor;		// no default
 static __u16 product;		// no default
 module_param(vendor, ushort, 0);
 MODULE_PARM_DESC(vendor, "User specified USB idVendor (required)");
 module_param(product, ushort, 0);
 MODULE_PARM_DESC(product, "User specified USB idProduct (required)");
 #endif

 module_param(debug, bool, S_IRUGO | S_IWUSR);
 MODULE_PARM_DESC(debug, "Debug enabled or not");

 module_param(safe, bool, 0);
 MODULE_PARM_DESC(safe, "Turn Safe Encapsulation On/Off");

 module_param(padded, bool, 0);
 MODULE_PARM_DESC(padded, "Pad to full wMaxPacketSize On/Off");

 #define CDC_DEVICE_CLASS                        0x02

 #define CDC_INTERFACE_CLASS                     0x02
 #define CDC_INTERFACE_SUBCLASS                  0x06

 #define LINEO_INTERFACE_CLASS                   0xff

 #define LINEO_INTERFACE_SUBCLASS_SAFENET        0x01
 #define LINEO_SAFENET_CRC                       0x01
 #define LINEO_SAFENET_CRC_PADDED                0x02

 #define LINEO_INTERFACE_SUBCLASS_SAFESERIAL     0x02
 #define LINEO_SAFESERIAL_CRC                    0x01
 #define LINEO_SAFESERIAL_CRC_PADDED             0x02


 #define MY_USB_DEVICE(vend,prod,dc,ic,isc) \
         .match_flags = USB_DEVICE_ID_MATCH_DEVICE | USB_DEVICE_ID_MATCH_DEV_CLASS | \
                 USB_DEVICE_ID_MATCH_INT_CLASS | USB_DEVICE_ID_MATCH_INT_SUBCLASS, \
         .idVendor = (vend), \
         .idProduct = (prod),\
         .bDeviceClass = (dc),\
         .bInterfaceClass = (ic), \
         .bInterfaceSubClass = (isc),

 static struct usb_device_id id_table[] = {
 	{MY_USB_DEVICE (0x49f, 0xffff, CDC_DEVICE_CLASS, LINEO_INTERFACE_CLASS, LINEO_INTERFACE_SUBCLASS_SAFESERIAL)},	// Itsy
 	{MY_USB_DEVICE (0x3f0, 0x2101, CDC_DEVICE_CLASS, LINEO_INTERFACE_CLASS, LINEO_INTERFACE_SUBCLASS_SAFESERIAL)},	// Calypso
 	{MY_USB_DEVICE (0x4dd, 0x8001, CDC_DEVICE_CLASS, LINEO_INTERFACE_CLASS, LINEO_INTERFACE_SUBCLASS_SAFESERIAL)},	// Iris
 	{MY_USB_DEVICE (0x4dd, 0x8002, CDC_DEVICE_CLASS, LINEO_INTERFACE_CLASS, LINEO_INTERFACE_SUBCLASS_SAFESERIAL)},	// Collie
 	{MY_USB_DEVICE (0x4dd, 0x8003, CDC_DEVICE_CLASS, LINEO_INTERFACE_CLASS, LINEO_INTERFACE_SUBCLASS_SAFESERIAL)},	// Collie
 	{MY_USB_DEVICE (0x4dd, 0x8004, CDC_DEVICE_CLASS, LINEO_INTERFACE_CLASS, LINEO_INTERFACE_SUBCLASS_SAFESERIAL)},	// Collie
 	{MY_USB_DEVICE (0x5f9, 0xffff, CDC_DEVICE_CLASS, LINEO_INTERFACE_CLASS, LINEO_INTERFACE_SUBCLASS_SAFESERIAL)},	// Sharp tmp
 #if defined(CONFIG_USB_SAFE_SERIAL_VENDOR)
 	{MY_USB_DEVICE
 	 (CONFIG_USB_SAFE_SERIAL_VENDOR, CONFIG_USB_SAFE_SERIAL_PRODUCT, CDC_DEVICE_CLASS,
 	  LINEO_INTERFACE_CLASS, LINEO_INTERFACE_SUBCLASS_SAFESERIAL)},
 #endif
 	// extra null entry for module
 	// vendor/produc parameters
 	{MY_USB_DEVICE (0, 0, CDC_DEVICE_CLASS, LINEO_INTERFACE_CLASS, LINEO_INTERFACE_SUBCLASS_SAFESERIAL)},
 	{}			// terminating entry
 };

 MODULE_DEVICE_TABLE (usb, id_table);

 static struct usb_driver safe_driver = {
 	.name =		"safe_serial",
 	.probe =	usb_serial_probe,
 	.disconnect =	usb_serial_disconnect,
 	.id_table =	id_table,
 	.no_dynamic_id = 	1,
 };

 static const __u16 crc10_table[256] = {
 	0x000, 0x233, 0x255, 0x066, 0x299, 0x0aa, 0x0cc, 0x2ff, 0x301, 0x132, 0x154, 0x367, 0x198, 0x3ab, 0x3cd, 0x1fe,
 	0x031, 0x202, 0x264, 0x057, 0x2a8, 0x09b, 0x0fd, 0x2ce, 0x330, 0x103, 0x165, 0x356, 0x1a9, 0x39a, 0x3fc, 0x1cf,
 	0x062, 0x251, 0x237, 0x004, 0x2fb, 0x0c8, 0x0ae, 0x29d, 0x363, 0x150, 0x136, 0x305, 0x1fa, 0x3c9, 0x3af, 0x19c,
 	0x053, 0x260, 0x206, 0x035, 0x2ca, 0x0f9, 0x09f, 0x2ac, 0x352, 0x161, 0x107, 0x334, 0x1cb, 0x3f8, 0x39e, 0x1ad,
 	0x0c4, 0x2f7, 0x291, 0x0a2, 0x25d, 0x06e, 0x008, 0x23b, 0x3c5, 0x1f6, 0x190, 0x3a3, 0x15c, 0x36f, 0x309, 0x13a,
 	0x0f5, 0x2c6, 0x2a0, 0x093, 0x26c, 0x05f, 0x039, 0x20a, 0x3f4, 0x1c7, 0x1a1, 0x392, 0x16d, 0x35e, 0x338, 0x10b,
 	0x0a6, 0x295, 0x2f3, 0x0c0, 0x23f, 0x00c, 0x06a, 0x259, 0x3a7, 0x194, 0x1f2, 0x3c1, 0x13e, 0x30d, 0x36b, 0x158,
 	0x097, 0x2a4, 0x2c2, 0x0f1, 0x20e, 0x03d, 0x05b, 0x268, 0x396, 0x1a5, 0x1c3, 0x3f0, 0x10f, 0x33c, 0x35a, 0x169,
 	0x188, 0x3bb, 0x3dd, 0x1ee, 0x311, 0x122, 0x144, 0x377, 0x289, 0x0ba, 0x0dc, 0x2ef, 0x010, 0x223, 0x245, 0x076,
 	0x1b9, 0x38a, 0x3ec, 0x1df, 0x320, 0x113, 0x175, 0x346, 0x2b8, 0x08b, 0x0ed, 0x2de, 0x021, 0x212, 0x274, 0x047,
 	0x1ea, 0x3d9, 0x3bf, 0x18c, 0x373, 0x140, 0x126, 0x315, 0x2eb, 0x0d8, 0x0be, 0x28d, 0x072, 0x241, 0x227, 0x014,
 	0x1db, 0x3e8, 0x38e, 0x1bd, 0x342, 0x171, 0x117, 0x324, 0x2da, 0x0e9, 0x08f, 0x2bc, 0x043, 0x270, 0x216, 0x025,
 	0x14c, 0x37f, 0x319, 0x12a, 0x3d5, 0x1e6, 0x180, 0x3b3, 0x24d, 0x07e, 0x018, 0x22b, 0x0d4, 0x2e7, 0x281, 0x0b2,
 	0x17d, 0x34e, 0x328, 0x11b, 0x3e4, 0x1d7, 0x1b1, 0x382, 0x27c, 0x04f, 0x029, 0x21a, 0x0e5, 0x2d6, 0x2b0, 0x083,
 	0x12e, 0x31d, 0x37b, 0x148, 0x3b7, 0x184, 0x1e2, 0x3d1, 0x22f, 0x01c, 0x07a, 0x249, 0x0b6, 0x285, 0x2e3, 0x0d0,
 	0x11f, 0x32c, 0x34a, 0x179, 0x386, 0x1b5, 0x1d3, 0x3e0, 0x21e, 0x02d, 0x04b, 0x278, 0x087, 0x2b4, 0x2d2, 0x0e1,
 };

 #define CRC10_INITFCS     0x000	// Initial FCS value
 #define CRC10_GOODFCS     0x000	// Good final FCS value
 #define CRC10_FCS(fcs, c) ( (((fcs) << 8) & 0x3ff) ^ crc10_table[((fcs) >> 2) & 0xff] ^ (c))

 /**
  * fcs_compute10 - memcpy and calculate 10 bit CRC across buffer
  * @sp: pointer to buffer
  * @len: number of bytes
  * @fcs: starting FCS
  *
  * Perform a memcpy and calculate fcs using ppp 10bit CRC algorithm. Return
  * new 10 bit FCS.
  */
 static __u16 __inline__ fcs_compute10 (unsigned char *sp, int len, __u16 fcs)
 {
 	for (; len-- > 0; fcs = CRC10_FCS (fcs, *sp++));
 	return fcs;
 }

 static void safe_read_bulk_callback (struct urb *urb, struct pt_regs *regs)
 {
 	struct usb_serial_port *port = (struct usb_serial_port *) urb->context;
 	unsigned char *data = urb->transfer_buffer;
 	unsigned char length = urb->actual_length;
 	int i;
 	int result;

 	dbg ("%s", __FUNCTION__);

 	if (urb->status) {
 		dbg ("%s - nonzero read bulk status received: %d", __FUNCTION__, urb->status);
 		return;
 	}

 	dbg ("safe_read_bulk_callback length: %d", port->read_urb->actual_length);
 #ifdef ECHO_RCV
 	{
 		int i;
 		unsigned char *cp = port->read_urb->transfer_buffer;
 		for (i = 0; i < port->read_urb->actual_length; i++) {
 			if ((i % 32) == 0) {
 				printk ("\nru[%02x] ", i);
 			}
 			printk ("%02x ", *cp++);
 		}
 		printk ("\n");
 	}
 #endif
 	if (safe) {
 		__u16 fcs;
 		if (!(fcs = fcs_compute10 (data, length, CRC10_INITFCS))) {

 			int actual_length = data[length - 2] >> 2;

 			if (actual_length <= (length - 2)) {

 				info ("%s - actual: %d", __FUNCTION__, actual_length);

 				for (i = 0; i < actual_length; i++) {
 					tty_insert_flip_char (port->tty, data[i], 0);
 				}
 				tty_flip_buffer_push (port->tty);
 			} else {
 				err ("%s - inconsistent lengths %d:%d", __FUNCTION__,
 				     actual_length, length);
 			}
 		} else {
 			err ("%s - bad CRC %x", __FUNCTION__, fcs);
 		}
 	} else {
 		for (i = 0; i < length; i++) {
 			tty_insert_flip_char (port->tty, data[i], 0);
 		}
 		tty_flip_buffer_push (port->tty);
 	}

 	/* Continue trying to always read  */
 	usb_fill_bulk_urb (urb, port->serial->dev,
 		       usb_rcvbulkpipe (port->serial->dev, port->bulk_in_endpointAddress),
 		       urb->transfer_buffer, urb->transfer_buffer_length,
 		       safe_read_bulk_callback, port);

 	if ((result = usb_submit_urb (urb, GFP_ATOMIC))) {
 		err ("%s - failed resubmitting read urb, error %d", __FUNCTION__, result);
 	}
 }

 static int safe_write (struct usb_serial_port *port, const unsigned char *buf, int count)
 {
 	unsigned char *data;
 	int result;
 	int i;
 	int packet_length;

 	dbg ("safe_write port: %p %d urb: %p count: %d", port, port->number, port->write_urb,
 	     count);

 	if (!port->write_urb) {
 		dbg ("%s - write urb NULL", __FUNCTION__);
 		return (0);
 	}

 	dbg ("safe_write write_urb: %d transfer_buffer_length",
 	     port->write_urb->transfer_buffer_length);

 	if (!port->write_urb->transfer_buffer_length) {
 		dbg ("%s - write urb transfer_buffer_length zero", __FUNCTION__);
 		return (0);
 	}
 	if (count == 0) {
 		dbg ("%s - write request of 0 bytes", __FUNCTION__);
 		return (0);
 	}
 	spin_lock_bh(&port->lock);
 	if (port->write_urb_busy) {
 		spin_unlock_bh(&port->lock);
 		dbg("%s - already writing", __FUNCTION__);
 		return 0;
 	}
 	port->write_urb_busy = 1;
 	spin_unlock_bh(&port->lock);

 	packet_length = port->bulk_out_size;	// get max packetsize

 	i = packet_length - (safe ? 2 : 0);	// get bytes to send
 	count = (count > i) ? i : count;


 	// get the data into the transfer buffer
 	data = port->write_urb->transfer_buffer;
 	memset (data, '0', packet_length);

 	memcpy (data, buf, count);

 	if (safe) {
 		__u16 fcs;

 		// pad if necessary
 		if (!padded) {
 			packet_length = count + 2;
 		}
 		// set count
 		data[packet_length - 2] = count << 2;
 		data[packet_length - 1] = 0;

 		// compute fcs and insert into trailer
 		fcs = fcs_compute10 (data, packet_length, CRC10_INITFCS);
 		data[packet_length - 2] |= fcs >> 8;
 		data[packet_length - 1] |= fcs & 0xff;

 		// set length to send
 		port->write_urb->transfer_buffer_length = packet_length;
 	} else {
 		port->write_urb->transfer_buffer_length = count;
 	}

 	usb_serial_debug_data(debug, &port->dev, __FUNCTION__, count, port->write_urb->transfer_buffer);
 #ifdef ECHO_TX
 	{
 		int i;
 		unsigned char *cp = port->write_urb->transfer_buffer;
 		for (i = 0; i < port->write_urb->transfer_buffer_length; i++) {
 			if ((i % 32) == 0) {
 				printk ("\nsu[%02x] ", i);
 			}
 			printk ("%02x ", *cp++);
 		}
 		printk ("\n");
 	}
 #endif
 	port->write_urb->dev = port->serial->dev;
 	if ((result = usb_submit_urb (port->write_urb, GFP_KERNEL))) {
 		port->write_urb_busy = 0;
 		err ("%s - failed submitting write urb, error %d", __FUNCTION__, result);
 		return 0;
 	}
 	dbg ("%s urb: %p submitted", __FUNCTION__, port->write_urb);

 	return (count);
 }

 static int safe_write_room (struct usb_serial_port *port)
 {
 	int room = 0;		// Default: no room

 	dbg ("%s", __FUNCTION__);

 	if (port->write_urb_busy)
 		room = port->bulk_out_size - (safe ? 2 : 0);

 	if (room) {
 		dbg ("safe_write_room returns %d", room);
 	}

 	return (room);
 }

 static int safe_startup (struct usb_serial *serial)
 {
 	switch (serial->interface->cur_altsetting->desc.bInterfaceProtocol) {
 	case LINEO_SAFESERIAL_CRC:
 		break;
 	case LINEO_SAFESERIAL_CRC_PADDED:
 		padded = 1;
 		break;
 	default:
 		return -EINVAL;
 	}
 	return 0;
 }

 static struct usb_serial_driver safe_device = {
 	.driver = {
 		.owner =	THIS_MODULE,
 		.name =		"safe_serial",
 	},
 	.id_table =		id_table,
 	.num_interrupt_in =	NUM_DONT_CARE,
 	.num_bulk_in =		NUM_DONT_CARE,
 	.num_bulk_out =		NUM_DONT_CARE,
 	.num_ports =		1,
 	.write =		safe_write,
 	.write_room =		safe_write_room,
 	.read_bulk_callback =	safe_read_bulk_callback,
 	.attach =		safe_startup,
 };

 static int __init safe_init (void)
 {
 	int i, retval;

 	info (DRIVER_VERSION " " DRIVER_AUTHOR);
 	info (DRIVER_DESC);
 	info ("vendor: %x product: %x safe: %d padded: %d\n", vendor, product, safe, padded);

 	// if we have vendor / product parameters patch them into id list
 	if (vendor || product) {
 		info ("vendor: %x product: %x\n", vendor, product);

 		for (i = 0; i < ARRAY_SIZE(id_table); i++) {
 			if (!id_table[i].idVendor && !id_table[i].idProduct) {
 				id_table[i].idVendor = vendor;
 				id_table[i].idProduct = product;
 				break;
 			}
 		}
 	}

 	retval = usb_serial_register(&safe_device);
 	if (retval)
 		goto failed_usb_serial_register;
 	retval = usb_register(&safe_driver);
 	if (retval)
 		goto failed_usb_register;

 	return 0;
 failed_usb_register:
 	usb_serial_deregister(&safe_device);
 failed_usb_serial_register:
 	return retval;
 }

 static void __exit safe_exit (void)
 {
 	usb_deregister (&safe_driver);
 	usb_serial_deregister (&safe_device);
 }

 module_init (safe_init);
 module_exit (safe_exit);
	/*
	* Safe Encapsulated USB Serial Driver
	*
	* Copyright (C) 2001 Lineo
	* Copyright (C) 2001 Hewlett-Packard
	*
	* 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.
	*
	* By:
	* Stuart Lynne <sl@lineo.com>, Tom Rushworth <tbr@lineo.com>
	*/

	/*
	* The encapsultaion is designed to overcome difficulties with some USB hardware.
	*
	* While the USB protocol has a CRC over the data while in transit, i.e. while
	* being carried over the bus, there is no end to end protection. If the hardware
	* has any problems getting the data into or out of the USB transmit and receive
	* FIFO's then data can be lost.
	*
	* This protocol adds a two byte trailer to each USB packet to specify the number
	* of bytes of valid data and a 10 bit CRC that will allow the receiver to verify
	* that the entire USB packet was received without error.
	*
	* Because in this case the sender and receiver are the class and function drivers
	* there is now end to end protection.
	*
	* There is an additional option that can be used to force all transmitted packets
	* to be padded to the maximum packet size. This provides a work around for some
	* devices which have problems with small USB packets.
	*
	* Assuming a packetsize of N:
	*
	* 0..N-2 data and optional padding
	*
	* N-2 bits 7-2 - number of bytes of valid data
	* bits 1-0 top two bits of 10 bit CRC
	* N-1 bottom 8 bits of 10 bit CRC
	*
	*
	* \| Data Length \| 10 bit CRC \|
	* + 7 . 6 . 5 . 4 . 3 . 2 . 1 . 0 \| 7 . 6 . 5 . 4 . 3 . 2 . 1 . 0 +
	*
	* The 10 bit CRC is computed across the sent data, followed by the trailer with
	* the length set and the CRC set to zero. The CRC is then OR'd into the trailer.
	*
	* When received a 10 bit CRC is computed over the entire frame including the trailer
	* and should be equal to zero.
	*
	* Two module parameters are used to control the encapsulation, if both are
	* turned of the module works as a simple serial device with NO
	* encapsulation.
	*
	* See linux/drivers/usbd/serial_fd for a device function driver
	* implementation of this.
	*
	*/


	#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/spinlock.h>
	#include <asm/uaccess.h>
	#include <linux/usb.h>
	#include <linux/usb/serial.h>


	#ifndef CONFIG_USB_SAFE_PADDED
	#define CONFIG_USB_SAFE_PADDED 0
	#endif

	static int debug;
	static int safe = 1;
	static int padded = CONFIG_USB_SAFE_PADDED;

	#define DRIVER_VERSION "v0.0b"
	#define DRIVER_AUTHOR "sl@lineo.com, tbr@lineo.com"
	#define DRIVER_DESC "USB Safe Encapsulated Serial"

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

	#if defined(CONFIG_USBD_SAFE_SERIAL_VENDOR) && !defined(CONFIG_USBD_SAFE_SERIAL_PRODUCT)
	#error "SAFE_SERIAL_VENDOR defined without SAFE_SERIAL_PRODUCT"
	#endif

	#if ! defined(CONFIG_USBD_SAFE_SERIAL_VENDOR)
	static __u16 vendor; // no default
	static __u16 product; // no default
	module_param(vendor, ushort, 0);
	MODULE_PARM_DESC(vendor, "User specified USB idVendor (required)");
	module_param(product, ushort, 0);
	MODULE_PARM_DESC(product, "User specified USB idProduct (required)");
	#endif

	module_param(debug, bool, S_IRUGO \| S_IWUSR);
	MODULE_PARM_DESC(debug, "Debug enabled or not");

	module_param(safe, bool, 0);
	MODULE_PARM_DESC(safe, "Turn Safe Encapsulation On/Off");

	module_param(padded, bool, 0);
	MODULE_PARM_DESC(padded, "Pad to full wMaxPacketSize On/Off");

	#define CDC_DEVICE_CLASS 0x02

	#define CDC_INTERFACE_CLASS 0x02
	#define CDC_INTERFACE_SUBCLASS 0x06

	#define LINEO_INTERFACE_CLASS 0xff

	#define LINEO_INTERFACE_SUBCLASS_SAFENET 0x01
	#define LINEO_SAFENET_CRC 0x01
	#define LINEO_SAFENET_CRC_PADDED 0x02

	#define LINEO_INTERFACE_SUBCLASS_SAFESERIAL 0x02
	#define LINEO_SAFESERIAL_CRC 0x01
	#define LINEO_SAFESERIAL_CRC_PADDED 0x02


	#define MY_USB_DEVICE(vend,prod,dc,ic,isc) \
	.match_flags = USB_DEVICE_ID_MATCH_DEVICE \| USB_DEVICE_ID_MATCH_DEV_CLASS \| \
	USB_DEVICE_ID_MATCH_INT_CLASS \| USB_DEVICE_ID_MATCH_INT_SUBCLASS, \
	.idVendor = (vend), \
	.idProduct = (prod),\
	.bDeviceClass = (dc),\
	.bInterfaceClass = (ic), \
	.bInterfaceSubClass = (isc),

	static struct usb_device_id id_table[] = {
	{MY_USB_DEVICE (0x49f, 0xffff, CDC_DEVICE_CLASS, LINEO_INTERFACE_CLASS, LINEO_INTERFACE_SUBCLASS_SAFESERIAL)}, // Itsy
	{MY_USB_DEVICE (0x3f0, 0x2101, CDC_DEVICE_CLASS, LINEO_INTERFACE_CLASS, LINEO_INTERFACE_SUBCLASS_SAFESERIAL)}, // Calypso
	{MY_USB_DEVICE (0x4dd, 0x8001, CDC_DEVICE_CLASS, LINEO_INTERFACE_CLASS, LINEO_INTERFACE_SUBCLASS_SAFESERIAL)}, // Iris
	{MY_USB_DEVICE (0x4dd, 0x8002, CDC_DEVICE_CLASS, LINEO_INTERFACE_CLASS, LINEO_INTERFACE_SUBCLASS_SAFESERIAL)}, // Collie
	{MY_USB_DEVICE (0x4dd, 0x8003, CDC_DEVICE_CLASS, LINEO_INTERFACE_CLASS, LINEO_INTERFACE_SUBCLASS_SAFESERIAL)}, // Collie
	{MY_USB_DEVICE (0x4dd, 0x8004, CDC_DEVICE_CLASS, LINEO_INTERFACE_CLASS, LINEO_INTERFACE_SUBCLASS_SAFESERIAL)}, // Collie
	{MY_USB_DEVICE (0x5f9, 0xffff, CDC_DEVICE_CLASS, LINEO_INTERFACE_CLASS, LINEO_INTERFACE_SUBCLASS_SAFESERIAL)}, // Sharp tmp
	#if defined(CONFIG_USB_SAFE_SERIAL_VENDOR)
	{MY_USB_DEVICE
	(CONFIG_USB_SAFE_SERIAL_VENDOR, CONFIG_USB_SAFE_SERIAL_PRODUCT, CDC_DEVICE_CLASS,
	LINEO_INTERFACE_CLASS, LINEO_INTERFACE_SUBCLASS_SAFESERIAL)},
	#endif
	// extra null entry for module
	// vendor/produc parameters
	{MY_USB_DEVICE (0, 0, CDC_DEVICE_CLASS, LINEO_INTERFACE_CLASS, LINEO_INTERFACE_SUBCLASS_SAFESERIAL)},
	{} // terminating entry
	};

	MODULE_DEVICE_TABLE (usb, id_table);

	static struct usb_driver safe_driver = {
	.name = "safe_serial",
	.probe = usb_serial_probe,
	.disconnect = usb_serial_disconnect,
	.id_table = id_table,
	.no_dynamic_id = 1,
	};

	static const __u16 crc10_table[256] = {
	0x000, 0x233, 0x255, 0x066, 0x299, 0x0aa, 0x0cc, 0x2ff, 0x301, 0x132, 0x154, 0x367, 0x198, 0x3ab, 0x3cd, 0x1fe,
	0x031, 0x202, 0x264, 0x057, 0x2a8, 0x09b, 0x0fd, 0x2ce, 0x330, 0x103, 0x165, 0x356, 0x1a9, 0x39a, 0x3fc, 0x1cf,
	0x062, 0x251, 0x237, 0x004, 0x2fb, 0x0c8, 0x0ae, 0x29d, 0x363, 0x150, 0x136, 0x305, 0x1fa, 0x3c9, 0x3af, 0x19c,
	0x053, 0x260, 0x206, 0x035, 0x2ca, 0x0f9, 0x09f, 0x2ac, 0x352, 0x161, 0x107, 0x334, 0x1cb, 0x3f8, 0x39e, 0x1ad,
	0x0c4, 0x2f7, 0x291, 0x0a2, 0x25d, 0x06e, 0x008, 0x23b, 0x3c5, 0x1f6, 0x190, 0x3a3, 0x15c, 0x36f, 0x309, 0x13a,
	0x0f5, 0x2c6, 0x2a0, 0x093, 0x26c, 0x05f, 0x039, 0x20a, 0x3f4, 0x1c7, 0x1a1, 0x392, 0x16d, 0x35e, 0x338, 0x10b,
	0x0a6, 0x295, 0x2f3, 0x0c0, 0x23f, 0x00c, 0x06a, 0x259, 0x3a7, 0x194, 0x1f2, 0x3c1, 0x13e, 0x30d, 0x36b, 0x158,
	0x097, 0x2a4, 0x2c2, 0x0f1, 0x20e, 0x03d, 0x05b, 0x268, 0x396, 0x1a5, 0x1c3, 0x3f0, 0x10f, 0x33c, 0x35a, 0x169,
	0x188, 0x3bb, 0x3dd, 0x1ee, 0x311, 0x122, 0x144, 0x377, 0x289, 0x0ba, 0x0dc, 0x2ef, 0x010, 0x223, 0x245, 0x076,
	0x1b9, 0x38a, 0x3ec, 0x1df, 0x320, 0x113, 0x175, 0x346, 0x2b8, 0x08b, 0x0ed, 0x2de, 0x021, 0x212, 0x274, 0x047,
	0x1ea, 0x3d9, 0x3bf, 0x18c, 0x373, 0x140, 0x126, 0x315, 0x2eb, 0x0d8, 0x0be, 0x28d, 0x072, 0x241, 0x227, 0x014,
	0x1db, 0x3e8, 0x38e, 0x1bd, 0x342, 0x171, 0x117, 0x324, 0x2da, 0x0e9, 0x08f, 0x2bc, 0x043, 0x270, 0x216, 0x025,
	0x14c, 0x37f, 0x319, 0x12a, 0x3d5, 0x1e6, 0x180, 0x3b3, 0x24d, 0x07e, 0x018, 0x22b, 0x0d4, 0x2e7, 0x281, 0x0b2,
	0x17d, 0x34e, 0x328, 0x11b, 0x3e4, 0x1d7, 0x1b1, 0x382, 0x27c, 0x04f, 0x029, 0x21a, 0x0e5, 0x2d6, 0x2b0, 0x083,
	0x12e, 0x31d, 0x37b, 0x148, 0x3b7, 0x184, 0x1e2, 0x3d1, 0x22f, 0x01c, 0x07a, 0x249, 0x0b6, 0x285, 0x2e3, 0x0d0,
	0x11f, 0x32c, 0x34a, 0x179, 0x386, 0x1b5, 0x1d3, 0x3e0, 0x21e, 0x02d, 0x04b, 0x278, 0x087, 0x2b4, 0x2d2, 0x0e1,
	};

	#define CRC10_INITFCS 0x000 // Initial FCS value
	#define CRC10_GOODFCS 0x000 // Good final FCS value
	#define CRC10_FCS(fcs, c) ( (((fcs) << 8) & 0x3ff) ^ crc10_table[((fcs) >> 2) & 0xff] ^ (c))

	/**
	* fcs_compute10 - memcpy and calculate 10 bit CRC across buffer
	* @sp: pointer to buffer
	* @len: number of bytes
	* @fcs: starting FCS
	*
	* Perform a memcpy and calculate fcs using ppp 10bit CRC algorithm. Return
	* new 10 bit FCS.
	*/
	static __u16 __inline__ fcs_compute10 (unsigned char *sp, int len, __u16 fcs)
	{
	for (; len-- > 0; fcs = CRC10_FCS (fcs, *sp++));
	return fcs;
	}

	static void safe_read_bulk_callback (struct urb urb, struct pt_regs regs)
	{
	struct usb_serial_port port = (struct usb_serial_port ) urb->context;
	unsigned char *data = urb->transfer_buffer;
	unsigned char length = urb->actual_length;
	int i;
	int result;

	dbg ("%s", __FUNCTION__);

	if (urb->status) {
	dbg ("%s - nonzero read bulk status received: %d", __FUNCTION__, urb->status);
	return;
	}

	dbg ("safe_read_bulk_callback length: %d", port->read_urb->actual_length);
	#ifdef ECHO_RCV
	{
	int i;
	unsigned char *cp = port->read_urb->transfer_buffer;
	for (i = 0; i < port->read_urb->actual_length; i++) {
	if ((i % 32) == 0) {
	printk ("\nru[%02x] ", i);
	}
	printk ("%02x ", *cp++);
	}
	printk ("\n");
	}
	#endif
	if (safe) {
	__u16 fcs;
	if (!(fcs = fcs_compute10 (data, length, CRC10_INITFCS))) {

	int actual_length = data[length - 2] >> 2;

	if (actual_length <= (length - 2)) {

	info ("%s - actual: %d", __FUNCTION__, actual_length);

	for (i = 0; i < actual_length; i++) {
	tty_insert_flip_char (port->tty, data[i], 0);
	}
	tty_flip_buffer_push (port->tty);
	} else {
	err ("%s - inconsistent lengths %d:%d", __FUNCTION__,
	actual_length, length);
	}
	} else {
	err ("%s - bad CRC %x", __FUNCTION__, fcs);
	}
	} else {
	for (i = 0; i < length; i++) {
	tty_insert_flip_char (port->tty, data[i], 0);
	}
	tty_flip_buffer_push (port->tty);
	}

	/* Continue trying to always read */
	usb_fill_bulk_urb (urb, port->serial->dev,
	usb_rcvbulkpipe (port->serial->dev, port->bulk_in_endpointAddress),
	urb->transfer_buffer, urb->transfer_buffer_length,
	safe_read_bulk_callback, port);

	if ((result = usb_submit_urb (urb, GFP_ATOMIC))) {
	err ("%s - failed resubmitting read urb, error %d", __FUNCTION__, result);
	}
	}

	static int safe_write (struct usb_serial_port port, const unsigned char buf, int count)
	{
	unsigned char *data;
	int result;
	int i;
	int packet_length;

	dbg ("safe_write port: %p %d urb: %p count: %d", port, port->number, port->write_urb,
	count);

	if (!port->write_urb) {
	dbg ("%s - write urb NULL", __FUNCTION__);
	return (0);
	}

	dbg ("safe_write write_urb: %d transfer_buffer_length",
	port->write_urb->transfer_buffer_length);

	if (!port->write_urb->transfer_buffer_length) {
	dbg ("%s - write urb transfer_buffer_length zero", __FUNCTION__);
	return (0);
	}
	if (count == 0) {
	dbg ("%s - write request of 0 bytes", __FUNCTION__);
	return (0);
	}
	spin_lock_bh(&port->lock);
	if (port->write_urb_busy) {
	spin_unlock_bh(&port->lock);
	dbg("%s - already writing", __FUNCTION__);
	return 0;
	}
	port->write_urb_busy = 1;
	spin_unlock_bh(&port->lock);

	packet_length = port->bulk_out_size; // get max packetsize

	i = packet_length - (safe ? 2 : 0); // get bytes to send
	count = (count > i) ? i : count;


	// get the data into the transfer buffer
	data = port->write_urb->transfer_buffer;
	memset (data, '0', packet_length);

	memcpy (data, buf, count);

	if (safe) {
	__u16 fcs;

	// pad if necessary
	if (!padded) {
	packet_length = count + 2;
	}
	// set count
	data[packet_length - 2] = count << 2;
	data[packet_length - 1] = 0;

	// compute fcs and insert into trailer
	fcs = fcs_compute10 (data, packet_length, CRC10_INITFCS);
	data[packet_length - 2] \|= fcs >> 8;
	data[packet_length - 1] \|= fcs & 0xff;

	// set length to send
	port->write_urb->transfer_buffer_length = packet_length;
	} else {
	port->write_urb->transfer_buffer_length = count;
	}

	usb_serial_debug_data(debug, &port->dev, __FUNCTION__, count, port->write_urb->transfer_buffer);
	#ifdef ECHO_TX
	{
	int i;
	unsigned char *cp = port->write_urb->transfer_buffer;
	for (i = 0; i < port->write_urb->transfer_buffer_length; i++) {
	if ((i % 32) == 0) {
	printk ("\nsu[%02x] ", i);
	}
	printk ("%02x ", *cp++);
	}
	printk ("\n");
	}
	#endif
	port->write_urb->dev = port->serial->dev;
	if ((result = usb_submit_urb (port->write_urb, GFP_KERNEL))) {
	port->write_urb_busy = 0;
	err ("%s - failed submitting write urb, error %d", __FUNCTION__, result);
	return 0;
	}
	dbg ("%s urb: %p submitted", __FUNCTION__, port->write_urb);

	return (count);
	}

	static int safe_write_room (struct usb_serial_port *port)
	{
	int room = 0; // Default: no room

	dbg ("%s", __FUNCTION__);

	if (port->write_urb_busy)
	room = port->bulk_out_size - (safe ? 2 : 0);

	if (room) {
	dbg ("safe_write_room returns %d", room);
	}

	return (room);
	}

	static int safe_startup (struct usb_serial *serial)
	{
	switch (serial->interface->cur_altsetting->desc.bInterfaceProtocol) {
	case LINEO_SAFESERIAL_CRC:
	break;
	case LINEO_SAFESERIAL_CRC_PADDED:
	padded = 1;
	break;
	default:
	return -EINVAL;
	}
	return 0;
	}

	static struct usb_serial_driver safe_device = {
	.driver = {
	.owner = THIS_MODULE,
	.name = "safe_serial",
	},
	.id_table = id_table,
	.num_interrupt_in = NUM_DONT_CARE,
	.num_bulk_in = NUM_DONT_CARE,
	.num_bulk_out = NUM_DONT_CARE,
	.num_ports = 1,
	.write = safe_write,
	.write_room = safe_write_room,
	.read_bulk_callback = safe_read_bulk_callback,
	.attach = safe_startup,
	};

	static int __init safe_init (void)
	{
	int i, retval;

	info (DRIVER_VERSION " " DRIVER_AUTHOR);
	info (DRIVER_DESC);
	info ("vendor: %x product: %x safe: %d padded: %d\n", vendor, product, safe, padded);

	// if we have vendor / product parameters patch them into id list
	if (vendor \|\| product) {
	info ("vendor: %x product: %x\n", vendor, product);

	for (i = 0; i < ARRAY_SIZE(id_table); i++) {
	if (!id_table[i].idVendor && !id_table[i].idProduct) {
	id_table[i].idVendor = vendor;
	id_table[i].idProduct = product;
	break;
	}
	}
	}

	retval = usb_serial_register(&safe_device);
	if (retval)
	goto failed_usb_serial_register;
	retval = usb_register(&safe_driver);
	if (retval)
	goto failed_usb_register;

	return 0;
	failed_usb_register:
	usb_serial_deregister(&safe_device);
	failed_usb_serial_register:
	return retval;
	}

	static void __exit safe_exit (void)
	{
	usb_deregister (&safe_driver);
	usb_serial_deregister (&safe_device);
	}

	module_init (safe_init);
	module_exit (safe_exit);