[deliverable/linux.git] / drivers / usb / serial / safe_serial.c

/*
 * Safe Encapsulated USB Serial Driver
 *
 *      Copyright (C) 2010 Johan Hovold <jhovold@gmail.com>
 *      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/gfp.h>
#include <linux/init.h>
#include <linux/tty.h>
#include <linux/tty_driver.h>
#include <linux/tty_flip.h>
#include <linux/module.h>
#include <linux/spinlock.h>
#include <linux/uaccess.h>
#include <linux/usb.h>
#include <linux/usb/serial.h>


#ifndef CONFIG_USB_SERIAL_SAFE_PADDED
#define CONFIG_USB_SERIAL_SAFE_PADDED 0
#endif

static bool debug;
static bool safe = 1;
static bool padded = CONFIG_USB_SERIAL_SAFE_PADDED;

#define DRIVER_VERSION "v0.1"
#define DRIVER_AUTHOR "sl@lineo.com, tbr@lineo.com, Johan Hovold <jhovold@gmail.com>"
#define DRIVER_DESC "USB Safe Encapsulated Serial"

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

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)");

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 */
	/* 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 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_process_read_urb(struct urb *urb)
{
	struct usb_serial_port *port = urb->context;
	unsigned char *data = urb->transfer_buffer;
	unsigned char length = urb->actual_length;
	int actual_length;
	struct tty_struct *tty;
	__u16 fcs;

	if (!length)
		return;

	tty = tty_port_tty_get(&port->port);
	if (!tty)
		return;

	if (!safe)
		goto out;

	fcs = fcs_compute10(data, length, CRC10_INITFCS);
	if (fcs) {
		dev_err(&port->dev, "%s - bad CRC %x\n", __func__, fcs);
		goto err;
	}

	actual_length = data[length - 2] >> 2;
	if (actual_length > (length - 2)) {
		dev_err(&port->dev, "%s - inconsistent lengths %d:%d\n",
				__func__, actual_length, length);
		goto err;
	}
	dev_info(&urb->dev->dev, "%s - actual: %d\n", __func__, actual_length);
	length = actual_length;
out:
	tty_insert_flip_string(tty, data, length);
	tty_flip_buffer_push(tty);
err:
	tty_kref_put(tty);
}

static int safe_prepare_write_buffer(struct usb_serial_port *port,
						void *dest, size_t size)
{
	unsigned char *buf = dest;
	int count;
	int trailer_len;
	int pkt_len;
	__u16 fcs;

	trailer_len = safe ? 2 : 0;

	count = kfifo_out_locked(&port->write_fifo, buf, size - trailer_len,
								&port->lock);
	if (!safe)
		return count;

	/* pad if necessary */
	if (padded) {
		pkt_len = size;
		memset(buf + count, '0', pkt_len - count - trailer_len);
	} else {
		pkt_len = count + trailer_len;
	}

	/* set count */
	buf[pkt_len - 2] = count << 2;
	buf[pkt_len - 1] = 0;

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

	return pkt_len;
}

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_ports =		1,
	.process_read_urb =	safe_process_read_urb,
	.prepare_write_buffer =	safe_prepare_write_buffer,
	.attach =		safe_startup,
};

static struct usb_serial_driver * const serial_drivers[] = {
	&safe_device, NULL
};

static int __init safe_init(void)
{
	int i;

	printk(KERN_INFO KBUILD_MODNAME ": " DRIVER_VERSION ":"
	       DRIVER_DESC "\n");

	/* if we have vendor / product parameters patch them into id list */
	if (vendor || product) {
		printk(KERN_INFO KBUILD_MODNAME ": 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;
			}
		}
	}

	return usb_serial_register_drivers(serial_drivers, KBUILD_MODNAME, id_table);
}

static void __exit safe_exit(void)
{
	usb_serial_deregister_drivers(serial_drivers);
}

module_init(safe_init);
module_exit(safe_exit);
Commit	Line	Data
1da177e4 LT	1	/*
	2	* Safe Encapsulated USB Serial Driver
	3	*
241c80ea	4	* Copyright (C) 2010 Johan Hovold <jhovold@gmail.com>
1da177e4 LT	5	* Copyright (C) 2001 Lineo
	6	* Copyright (C) 2001 Hewlett-Packard
	7	*
	8	* This program is free software; you can redistribute it and/or modify
	9	* it under the terms of the GNU General Public License as published by
	10	* the Free Software Foundation; either version 2 of the License, or
	11	* (at your option) any later version.
	12	*
	13	* By:
	14	* Stuart Lynne <sl@lineo.com>, Tom Rushworth <tbr@lineo.com>
	15	*/
	16
43c8f435 AC	17	/*
	18	* The encapsultaion is designed to overcome difficulties with some USB
	19	* hardware.
1da177e4 LT	20	*
1da177e4 LT	21	* While the USB protocol has a CRC over the data while in transit, i.e. while
43c8f435 AC	22	* being carried over the bus, there is no end to end protection. If the
	23	* hardware has any problems getting the data into or out of the USB transmit
	24	* and receive FIFO's then data can be lost.
1da177e4	25	*
43c8f435 AC	26	* This protocol adds a two byte trailer to each USB packet to specify the
	27	* number of bytes of valid data and a 10 bit CRC that will allow the receiver
	28	* to verify that the entire USB packet was received without error.
1da177e4	29	*
43c8f435 AC	30	* Because in this case the sender and receiver are the class and function
43c8f435 AC	31	* drivers there is now end to end protection.
1da177e4	32	*
43c8f435 AC	33	* There is an additional option that can be used to force all transmitted
	34	* packets to be padded to the maximum packet size. This provides a work
	35	* around for some devices which have problems with small USB packets.
1da177e4 LT	36	*
	37	* Assuming a packetsize of N:
	38	*
	39	* 0..N-2 data and optional padding
	40	*
	41	* N-2 bits 7-2 - number of bytes of valid data
	42	* bits 1-0 top two bits of 10 bit CRC
	43	* N-1 bottom 8 bits of 10 bit CRC
	44	*
	45	*
	46	* \| Data Length \| 10 bit CRC \|
	47	* + 7 . 6 . 5 . 4 . 3 . 2 . 1 . 0 \| 7 . 6 . 5 . 4 . 3 . 2 . 1 . 0 +
	48	*
43c8f435 AC	49	* The 10 bit CRC is computed across the sent data, followed by the trailer
	50	* with the length set and the CRC set to zero. The CRC is then OR'd into
	51	* the trailer.
1da177e4	52	*
43c8f435 AC	53	* When received a 10 bit CRC is computed over the entire frame including
43c8f435 AC	54	* the trailer and should be equal to zero.
1da177e4 LT	55	*
	56	* Two module parameters are used to control the encapsulation, if both are
	57	* turned of the module works as a simple serial device with NO
	58	* encapsulation.
	59	*
	60	* See linux/drivers/usbd/serial_fd for a device function driver
	61	* implementation of this.
	62	*
	63	*/
	64
	65
1da177e4 LT	66	#include <linux/kernel.h>
1da177e4 LT	67	#include <linux/errno.h>
5a0e3ad6	68	#include <linux/gfp.h>
1da177e4	69	#include <linux/init.h>
1da177e4 LT	70	#include <linux/tty.h>
	71	#include <linux/tty_driver.h>
	72	#include <linux/tty_flip.h>
	73	#include <linux/module.h>
	74	#include <linux/spinlock.h>
43c8f435	75	#include <linux/uaccess.h>
1da177e4	76	#include <linux/usb.h>
a969888c	77	#include <linux/usb/serial.h>
1da177e4 LT	78
1da177e4 LT	79
3aec6e26 RD	80	#ifndef CONFIG_USB_SERIAL_SAFE_PADDED
3aec6e26 RD	81	#define CONFIG_USB_SERIAL_SAFE_PADDED 0
1da177e4 LT	82	#endif
1da177e4 LT	83
90ab5ee9 RR	84	static bool debug;
	85	static bool safe = 1;
	86	static bool padded = CONFIG_USB_SERIAL_SAFE_PADDED;
1da177e4	87
241c80ea JH	88	#define DRIVER_VERSION "v0.1"
241c80ea JH	89	#define DRIVER_AUTHOR "sl@lineo.com, tbr@lineo.com, Johan Hovold <jhovold@gmail.com>"
1da177e4 LT	90	#define DRIVER_DESC "USB Safe Encapsulated Serial"
1da177e4 LT	91
43c8f435 AC	92	MODULE_AUTHOR(DRIVER_AUTHOR);
43c8f435 AC	93	MODULE_DESCRIPTION(DRIVER_DESC);
1da177e4 LT	94	MODULE_LICENSE("GPL");
1da177e4 LT	95
43c8f435 AC	96	static __u16 vendor; /* no default */
43c8f435 AC	97	static __u16 product; /* no default */
1da177e4 LT	98	module_param(vendor, ushort, 0);
	99	MODULE_PARM_DESC(vendor, "User specified USB idVendor (required)");
	100	module_param(product, ushort, 0);
	101	MODULE_PARM_DESC(product, "User specified USB idProduct (required)");
1da177e4 LT	102
	103	module_param(debug, bool, S_IRUGO \| S_IWUSR);
	104	MODULE_PARM_DESC(debug, "Debug enabled or not");
	105
	106	module_param(safe, bool, 0);
	107	MODULE_PARM_DESC(safe, "Turn Safe Encapsulation On/Off");
	108
	109	module_param(padded, bool, 0);
	110	MODULE_PARM_DESC(padded, "Pad to full wMaxPacketSize On/Off");
	111
	112	#define CDC_DEVICE_CLASS 0x02
	113
	114	#define CDC_INTERFACE_CLASS 0x02
	115	#define CDC_INTERFACE_SUBCLASS 0x06
	116
	117	#define LINEO_INTERFACE_CLASS 0xff
	118
	119	#define LINEO_INTERFACE_SUBCLASS_SAFENET 0x01
	120	#define LINEO_SAFENET_CRC 0x01
	121	#define LINEO_SAFENET_CRC_PADDED 0x02
	122
	123	#define LINEO_INTERFACE_SUBCLASS_SAFESERIAL 0x02
	124	#define LINEO_SAFESERIAL_CRC 0x01
	125	#define LINEO_SAFESERIAL_CRC_PADDED 0x02
	126
	127
43c8f435 AC	128	#define MY_USB_DEVICE(vend, prod, dc, ic, isc) \
	129	.match_flags = USB_DEVICE_ID_MATCH_DEVICE \| \
	130	USB_DEVICE_ID_MATCH_DEV_CLASS \| \
	131	USB_DEVICE_ID_MATCH_INT_CLASS \| \
	132	USB_DEVICE_ID_MATCH_INT_SUBCLASS, \
	133	.idVendor = (vend), \
	134	.idProduct = (prod),\
	135	.bDeviceClass = (dc),\
	136	.bInterfaceClass = (ic), \
	137	.bInterfaceSubClass = (isc),
1da177e4 LT	138
1da177e4 LT	139	static struct usb_device_id id_table[] = {
43c8f435 AC	140	{MY_USB_DEVICE(0x49f, 0xffff, CDC_DEVICE_CLASS, LINEO_INTERFACE_CLASS, LINEO_INTERFACE_SUBCLASS_SAFESERIAL)}, /* Itsy */
	141	{MY_USB_DEVICE(0x3f0, 0x2101, CDC_DEVICE_CLASS, LINEO_INTERFACE_CLASS, LINEO_INTERFACE_SUBCLASS_SAFESERIAL)}, /* Calypso */
	142	{MY_USB_DEVICE(0x4dd, 0x8001, CDC_DEVICE_CLASS, LINEO_INTERFACE_CLASS, LINEO_INTERFACE_SUBCLASS_SAFESERIAL)}, /* Iris */
	143	{MY_USB_DEVICE(0x4dd, 0x8002, CDC_DEVICE_CLASS, LINEO_INTERFACE_CLASS, LINEO_INTERFACE_SUBCLASS_SAFESERIAL)}, /* Collie */
	144	{MY_USB_DEVICE(0x4dd, 0x8003, CDC_DEVICE_CLASS, LINEO_INTERFACE_CLASS, LINEO_INTERFACE_SUBCLASS_SAFESERIAL)}, /* Collie */
	145	{MY_USB_DEVICE(0x4dd, 0x8004, CDC_DEVICE_CLASS, LINEO_INTERFACE_CLASS, LINEO_INTERFACE_SUBCLASS_SAFESERIAL)}, /* Collie */
	146	{MY_USB_DEVICE(0x5f9, 0xffff, CDC_DEVICE_CLASS, LINEO_INTERFACE_CLASS, LINEO_INTERFACE_SUBCLASS_SAFESERIAL)}, /* Sharp tmp */
	147	/* extra null entry for module vendor/produc parameters */
	148	{MY_USB_DEVICE(0, 0, CDC_DEVICE_CLASS, LINEO_INTERFACE_CLASS, LINEO_INTERFACE_SUBCLASS_SAFESERIAL)},
	149	{} /* terminating entry */
1da177e4 LT	150	};
1da177e4 LT	151
43c8f435	152	MODULE_DEVICE_TABLE(usb, id_table);
1da177e4	153
4c4c9432	154	static const __u16 crc10_table[256] = {
43c8f435 AC	155	0x000, 0x233, 0x255, 0x066, 0x299, 0x0aa, 0x0cc, 0x2ff,
	156	0x301, 0x132, 0x154, 0x367, 0x198, 0x3ab, 0x3cd, 0x1fe,
	157	0x031, 0x202, 0x264, 0x057, 0x2a8, 0x09b, 0x0fd, 0x2ce,
	158	0x330, 0x103, 0x165, 0x356, 0x1a9, 0x39a, 0x3fc, 0x1cf,
	159	0x062, 0x251, 0x237, 0x004, 0x2fb, 0x0c8, 0x0ae, 0x29d,
	160	0x363, 0x150, 0x136, 0x305, 0x1fa, 0x3c9, 0x3af, 0x19c,
	161	0x053, 0x260, 0x206, 0x035, 0x2ca, 0x0f9, 0x09f, 0x2ac,
	162	0x352, 0x161, 0x107, 0x334, 0x1cb, 0x3f8, 0x39e, 0x1ad,
	163	0x0c4, 0x2f7, 0x291, 0x0a2, 0x25d, 0x06e, 0x008, 0x23b,
	164	0x3c5, 0x1f6, 0x190, 0x3a3, 0x15c, 0x36f, 0x309, 0x13a,
	165	0x0f5, 0x2c6, 0x2a0, 0x093, 0x26c, 0x05f, 0x039, 0x20a,
	166	0x3f4, 0x1c7, 0x1a1, 0x392, 0x16d, 0x35e, 0x338, 0x10b,
	167	0x0a6, 0x295, 0x2f3, 0x0c0, 0x23f, 0x00c, 0x06a, 0x259,
	168	0x3a7, 0x194, 0x1f2, 0x3c1, 0x13e, 0x30d, 0x36b, 0x158,
	169	0x097, 0x2a4, 0x2c2, 0x0f1, 0x20e, 0x03d, 0x05b, 0x268,
	170	0x396, 0x1a5, 0x1c3, 0x3f0, 0x10f, 0x33c, 0x35a, 0x169,
	171	0x188, 0x3bb, 0x3dd, 0x1ee, 0x311, 0x122, 0x144, 0x377,
	172	0x289, 0x0ba, 0x0dc, 0x2ef, 0x010, 0x223, 0x245, 0x076,
	173	0x1b9, 0x38a, 0x3ec, 0x1df, 0x320, 0x113, 0x175, 0x346,
	174	0x2b8, 0x08b, 0x0ed, 0x2de, 0x021, 0x212, 0x274, 0x047,
	175	0x1ea, 0x3d9, 0x3bf, 0x18c, 0x373, 0x140, 0x126, 0x315,
	176	0x2eb, 0x0d8, 0x0be, 0x28d, 0x072, 0x241, 0x227, 0x014,
	177	0x1db, 0x3e8, 0x38e, 0x1bd, 0x342, 0x171, 0x117, 0x324,
	178	0x2da, 0x0e9, 0x08f, 0x2bc, 0x043, 0x270, 0x216, 0x025,
	179	0x14c, 0x37f, 0x319, 0x12a, 0x3d5, 0x1e6, 0x180, 0x3b3,
	180	0x24d, 0x07e, 0x018, 0x22b, 0x0d4, 0x2e7, 0x281, 0x0b2,
	181	0x17d, 0x34e, 0x328, 0x11b, 0x3e4, 0x1d7, 0x1b1, 0x382,
	182	0x27c, 0x04f, 0x029, 0x21a, 0x0e5, 0x2d6, 0x2b0, 0x083,
	183	0x12e, 0x31d, 0x37b, 0x148, 0x3b7, 0x184, 0x1e2, 0x3d1,
	184	0x22f, 0x01c, 0x07a, 0x249, 0x0b6, 0x285, 0x2e3, 0x0d0,
	185	0x11f, 0x32c, 0x34a, 0x179, 0x386, 0x1b5, 0x1d3, 0x3e0,
	186	0x21e, 0x02d, 0x04b, 0x278, 0x087, 0x2b4, 0x2d2, 0x0e1,
1da177e4 LT	187	};
1da177e4 LT	188
43c8f435 AC	189	#define CRC10_INITFCS 0x000 /* Initial FCS value */
	190	#define CRC10_GOODFCS 0x000 /* Good final FCS value */
	191	#define CRC10_FCS(fcs, c) ((((fcs) << 8) & 0x3ff) ^ crc10_table[((fcs) >> 2) & 0xff] ^ (c))
1da177e4	192
43c8f435	193	/**
1da177e4 LT	194	* fcs_compute10 - memcpy and calculate 10 bit CRC across buffer
	195	* @sp: pointer to buffer
	196	* @len: number of bytes
	197	* @fcs: starting FCS
	198	*
	199	* Perform a memcpy and calculate fcs using ppp 10bit CRC algorithm. Return
	200	* new 10 bit FCS.
	201	*/
43c8f435	202	static __u16 __inline__ fcs_compute10(unsigned char *sp, int len, __u16 fcs)
1da177e4	203	{
43c8f435	204	for (; len-- > 0; fcs = CRC10_FCS(fcs, *sp++));
1da177e4 LT	205	return fcs;
	206	}
	207
12e2e52c	208	static void safe_process_read_urb(struct urb *urb)
1da177e4	209	{
12e2e52c	210	struct usb_serial_port *port = urb->context;
1da177e4 LT	211	unsigned char *data = urb->transfer_buffer;
1da177e4 LT	212	unsigned char length = urb->actual_length;
6d1bf48e	213	int actual_length;
4a90f09b	214	struct tty_struct *tty;
6d1bf48e	215	__u16 fcs;
1da177e4	216
12e2e52c	217	if (!length)
1da177e4	218	return;
1da177e4	219
4a90f09b	220	tty = tty_port_tty_get(&port->port);
12e2e52c JH	221	if (!tty)
	222	return;
	223
6d1bf48e JH	224	if (!safe)
	225	goto out;
	226
	227	fcs = fcs_compute10(data, length, CRC10_INITFCS);
	228	if (fcs) {
	229	dev_err(&port->dev, "%s - bad CRC %x\n", __func__, fcs);
	230	goto err;
1da177e4 LT	231	}
1da177e4 LT	232
6d1bf48e JH	233	actual_length = data[length - 2] >> 2;
	234	if (actual_length > (length - 2)) {
	235	dev_err(&port->dev, "%s - inconsistent lengths %d:%d\n",
	236	__func__, actual_length, length);
	237	goto err;
	238	}
	239	dev_info(&urb->dev->dev, "%s - actual: %d\n", __func__, actual_length);
	240	length = actual_length;
	241	out:
	242	tty_insert_flip_string(tty, data, length);
	243	tty_flip_buffer_push(tty);
	244	err:
12e2e52c	245	tty_kref_put(tty);
1da177e4 LT	246	}
1da177e4 LT	247
241c80ea JH	248	static int safe_prepare_write_buffer(struct usb_serial_port *port,
241c80ea JH	249	void *dest, size_t size)
1da177e4	250	{
241c80ea JH	251	unsigned char *buf = dest;
	252	int count;
	253	int trailer_len;
	254	int pkt_len;
	255	__u16 fcs;
	256
	257	trailer_len = safe ? 2 : 0;
	258
	259	count = kfifo_out_locked(&port->write_fifo, buf, size - trailer_len,
	260	&port->lock);
	261	if (!safe)
	262	return count;
	263
	264	/* pad if necessary */
	265	if (padded) {
	266	pkt_len = size;
	267	memset(buf + count, '0', pkt_len - count - trailer_len);
1da177e4	268	} else {
241c80ea	269	pkt_len = count + trailer_len;
1da177e4	270	}
1da177e4	271
241c80ea JH	272	/* set count */
	273	buf[pkt_len - 2] = count << 2;
	274	buf[pkt_len - 1] = 0;
1da177e4	275
241c80ea JH	276	/* compute fcs and insert into trailer */
	277	fcs = fcs_compute10(buf, pkt_len, CRC10_INITFCS);
	278	buf[pkt_len - 2] \|= fcs >> 8;
	279	buf[pkt_len - 1] \|= fcs & 0xff;
1da177e4	280
241c80ea	281	return pkt_len;
1da177e4 LT	282	}
1da177e4 LT	283
43c8f435	284	static int safe_startup(struct usb_serial *serial)
1da177e4 LT	285	{
	286	switch (serial->interface->cur_altsetting->desc.bInterfaceProtocol) {
	287	case LINEO_SAFESERIAL_CRC:
	288	break;
	289	case LINEO_SAFESERIAL_CRC_PADDED:
	290	padded = 1;
	291	break;
	292	default:
	293	return -EINVAL;
	294	}
	295	return 0;
	296	}
	297
ea65370d	298	static struct usb_serial_driver safe_device = {
18fcac35 GKH	299	.driver = {
18fcac35 GKH	300	.owner = THIS_MODULE,
269bda1c	301	.name = "safe_serial",
18fcac35	302	},
1da177e4	303	.id_table = id_table,
1da177e4	304	.num_ports = 1,
12e2e52c	305	.process_read_urb = safe_process_read_urb,
241c80ea	306	.prepare_write_buffer = safe_prepare_write_buffer,
1da177e4 LT	307	.attach = safe_startup,
	308	};
	309
d860322f AS	310	static struct usb_serial_driver * const serial_drivers[] = {
	311	&safe_device, NULL
	312	};
	313
43c8f435	314	static int __init safe_init(void)
1da177e4	315	{
d860322f	316	int i;
1da177e4	317
c197a8db GKH	318	printk(KERN_INFO KBUILD_MODNAME ": " DRIVER_VERSION ":"
c197a8db GKH	319	DRIVER_DESC "\n");
1da177e4	320
43c8f435	321	/* if we have vendor / product parameters patch them into id list */
1da177e4	322	if (vendor \|\| product) {
c197a8db GKH	323	printk(KERN_INFO KBUILD_MODNAME ": vendor: %x product: %x\n",
c197a8db GKH	324	vendor, product);
1da177e4	325
52950ed4	326	for (i = 0; i < ARRAY_SIZE(id_table); i++) {
1da177e4 LT	327	if (!id_table[i].idVendor && !id_table[i].idProduct) {
	328	id_table[i].idVendor = vendor;
	329	id_table[i].idProduct = product;
	330	break;
	331	}
	332	}
	333	}
	334
68e24113	335	return usb_serial_register_drivers(serial_drivers, KBUILD_MODNAME, id_table);
1da177e4 LT	336	}
1da177e4 LT	337
43c8f435	338	static void __exit safe_exit(void)
1da177e4	339	{
68e24113	340	usb_serial_deregister_drivers(serial_drivers);
1da177e4 LT	341	}
1da177e4 LT	342
43c8f435 AC	343	module_init(safe_init);
43c8f435 AC	344	module_exit(safe_exit);