2 * Safe Encapsulated USB Serial Driver
4 * Copyright (C) 2001 Lineo
5 * Copyright (C) 2001 Hewlett-Packard
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
13 * Stuart Lynne <sl@lineo.com>, Tom Rushworth <tbr@lineo.com>
17 * The encapsultaion is designed to overcome difficulties with some USB hardware.
19 * While the USB protocol has a CRC over the data while in transit, i.e. while
20 * being carried over the bus, there is no end to end protection. If the hardware
21 * has any problems getting the data into or out of the USB transmit and receive
22 * FIFO's then data can be lost.
24 * This protocol adds a two byte trailer to each USB packet to specify the number
25 * of bytes of valid data and a 10 bit CRC that will allow the receiver to verify
26 * that the entire USB packet was received without error.
28 * Because in this case the sender and receiver are the class and function drivers
29 * there is now end to end protection.
31 * There is an additional option that can be used to force all transmitted packets
32 * to be padded to the maximum packet size. This provides a work around for some
33 * devices which have problems with small USB packets.
35 * Assuming a packetsize of N:
37 * 0..N-2 data and optional padding
39 * N-2 bits 7-2 - number of bytes of valid data
40 * bits 1-0 top two bits of 10 bit CRC
41 * N-1 bottom 8 bits of 10 bit CRC
44 * | Data Length | 10 bit CRC |
45 * + 7 . 6 . 5 . 4 . 3 . 2 . 1 . 0 | 7 . 6 . 5 . 4 . 3 . 2 . 1 . 0 +
47 * The 10 bit CRC is computed across the sent data, followed by the trailer with
48 * the length set and the CRC set to zero. The CRC is then OR'd into the trailer.
50 * When received a 10 bit CRC is computed over the entire frame including the trailer
51 * and should be equal to zero.
53 * Two module parameters are used to control the encapsulation, if both are
54 * turned of the module works as a simple serial device with NO
57 * See linux/drivers/usbd/serial_fd for a device function driver
58 * implementation of this.
63 #include <linux/config.h>
64 #include <linux/kernel.h>
65 #include <linux/errno.h>
66 #include <linux/init.h>
67 #include <linux/slab.h>
68 #include <linux/tty.h>
69 #include <linux/tty_driver.h>
70 #include <linux/tty_flip.h>
71 #include <linux/module.h>
72 #include <linux/spinlock.h>
73 #include <asm/uaccess.h>
74 #include <linux/usb.h>
77 #ifndef CONFIG_USB_SERIAL_DEBUG
78 #define CONFIG_USB_SERIAL_DEBUG 0
80 #ifndef CONFIG_USB_SAFE_PADDED
81 #define CONFIG_USB_SAFE_PADDED 0
84 static int debug = CONFIG_USB_SERIAL_DEBUG;
85 #include "usb-serial.h" // must follow the declaration of debug
88 static int padded = CONFIG_USB_SAFE_PADDED;
90 #define DRIVER_VERSION "v0.0b"
91 #define DRIVER_AUTHOR "sl@lineo.com, tbr@lineo.com"
92 #define DRIVER_DESC "USB Safe Encapsulated Serial"
94 MODULE_AUTHOR (DRIVER_AUTHOR);
95 MODULE_DESCRIPTION (DRIVER_DESC);
96 MODULE_LICENSE("GPL");
98 #if defined(CONFIG_USBD_SAFE_SERIAL_VENDOR) && !defined(CONFIG_USBD_SAFE_SERIAL_PRODUCT)
99 #abort "SAFE_SERIAL_VENDOR defined without SAFE_SERIAL_PRODUCT"
102 #if ! defined(CONFIG_USBD_SAFE_SERIAL_VENDOR)
103 static __u16 vendor; // no default
104 static __u16 product; // no default
105 MODULE_PARM (vendor, "i");
106 MODULE_PARM (product, "i");
107 MODULE_PARM_DESC (vendor, "User specified USB idVendor (required)");
108 MODULE_PARM_DESC (product, "User specified USB idProduct (required)");
111 MODULE_PARM (debug, "i");
112 MODULE_PARM (safe, "i");
113 MODULE_PARM (padded, "i");
115 MODULE_PARM_DESC (debug, "Debug enabled or not");
116 MODULE_PARM_DESC (safe, "Turn Safe Encapsulation On/Off");
117 MODULE_PARM_DESC (padded, "Pad to full wMaxPacketSize On/Off");
119 #define CDC_DEVICE_CLASS 0x02
121 #define CDC_INTERFACE_CLASS 0x02
122 #define CDC_INTERFACE_SUBCLASS 0x06
124 #define LINEO_INTERFACE_CLASS 0xff
126 #define LINEO_INTERFACE_SUBCLASS_SAFENET 0x01
127 #define LINEO_SAFENET_CRC 0x01
128 #define LINEO_SAFENET_CRC_PADDED 0x02
130 #define LINEO_INTERFACE_SUBCLASS_SAFESERIAL 0x02
131 #define LINEO_SAFESERIAL_CRC 0x01
132 #define LINEO_SAFESERIAL_CRC_PADDED 0x02
135 #define MY_USB_DEVICE(vend,prod,dc,ic,isc) \
136 .match_flags = USB_DEVICE_ID_MATCH_DEVICE | USB_DEVICE_ID_MATCH_DEV_CLASS | \
137 USB_DEVICE_ID_MATCH_INT_CLASS | USB_DEVICE_ID_MATCH_INT_SUBCLASS, \
138 .idVendor = (vend), \
139 .idProduct = (prod),\
140 .bDeviceClass = (dc),\
141 .bInterfaceClass = (ic), \
142 .bInterfaceSubClass = (isc),
144 static struct usb_device_id id_table[] = {
145 {MY_USB_DEVICE (0x49f, 0xffff, CDC_DEVICE_CLASS, LINEO_INTERFACE_CLASS, LINEO_INTERFACE_SUBCLASS_SAFESERIAL)}, // Itsy
146 {MY_USB_DEVICE (0x3f0, 0x2101, CDC_DEVICE_CLASS, LINEO_INTERFACE_CLASS, LINEO_INTERFACE_SUBCLASS_SAFESERIAL)}, // Calypso
147 {MY_USB_DEVICE (0x4dd, 0x8001, CDC_DEVICE_CLASS, LINEO_INTERFACE_CLASS, LINEO_INTERFACE_SUBCLASS_SAFESERIAL)}, // Iris
148 {MY_USB_DEVICE (0x4dd, 0x8002, CDC_DEVICE_CLASS, LINEO_INTERFACE_CLASS, LINEO_INTERFACE_SUBCLASS_SAFESERIAL)}, // Collie
149 {MY_USB_DEVICE (0x4dd, 0x8003, CDC_DEVICE_CLASS, LINEO_INTERFACE_CLASS, LINEO_INTERFACE_SUBCLASS_SAFESERIAL)}, // Collie
150 {MY_USB_DEVICE (0x4dd, 0x8004, CDC_DEVICE_CLASS, LINEO_INTERFACE_CLASS, LINEO_INTERFACE_SUBCLASS_SAFESERIAL)}, // Collie
151 {MY_USB_DEVICE (0x5f9, 0xffff, CDC_DEVICE_CLASS, LINEO_INTERFACE_CLASS, LINEO_INTERFACE_SUBCLASS_SAFESERIAL)}, // Sharp tmp
152 #if defined(CONFIG_USB_SAFE_SERIAL_VENDOR)
154 (CONFIG_USB_SAFE_SERIAL_VENDOR, CONFIG_USB_SAFE_SERIAL_PRODUCT, CDC_DEVICE_CLASS,
155 LINEO_INTERFACE_CLASS, LINEO_INTERFACE_SUBCLASS_SAFESERIAL)},
157 // extra null entry for module
158 // vendor/produc parameters
159 {MY_USB_DEVICE (0, 0, CDC_DEVICE_CLASS, LINEO_INTERFACE_CLASS, LINEO_INTERFACE_SUBCLASS_SAFESERIAL)},
160 {} // terminating entry
163 MODULE_DEVICE_TABLE (usb, id_table);
165 static struct usb_driver safe_driver = {
166 .owner = THIS_MODULE,
167 .name = "safe_serial",
168 .probe = usb_serial_probe,
169 .disconnect = usb_serial_disconnect,
170 .id_table = id_table,
173 static __u16 crc10_table[256] = {
174 0x000, 0x233, 0x255, 0x066, 0x299, 0x0aa, 0x0cc, 0x2ff, 0x301, 0x132, 0x154, 0x367, 0x198, 0x3ab, 0x3cd, 0x1fe,
175 0x031, 0x202, 0x264, 0x057, 0x2a8, 0x09b, 0x0fd, 0x2ce, 0x330, 0x103, 0x165, 0x356, 0x1a9, 0x39a, 0x3fc, 0x1cf,
176 0x062, 0x251, 0x237, 0x004, 0x2fb, 0x0c8, 0x0ae, 0x29d, 0x363, 0x150, 0x136, 0x305, 0x1fa, 0x3c9, 0x3af, 0x19c,
177 0x053, 0x260, 0x206, 0x035, 0x2ca, 0x0f9, 0x09f, 0x2ac, 0x352, 0x161, 0x107, 0x334, 0x1cb, 0x3f8, 0x39e, 0x1ad,
178 0x0c4, 0x2f7, 0x291, 0x0a2, 0x25d, 0x06e, 0x008, 0x23b, 0x3c5, 0x1f6, 0x190, 0x3a3, 0x15c, 0x36f, 0x309, 0x13a,
179 0x0f5, 0x2c6, 0x2a0, 0x093, 0x26c, 0x05f, 0x039, 0x20a, 0x3f4, 0x1c7, 0x1a1, 0x392, 0x16d, 0x35e, 0x338, 0x10b,
180 0x0a6, 0x295, 0x2f3, 0x0c0, 0x23f, 0x00c, 0x06a, 0x259, 0x3a7, 0x194, 0x1f2, 0x3c1, 0x13e, 0x30d, 0x36b, 0x158,
181 0x097, 0x2a4, 0x2c2, 0x0f1, 0x20e, 0x03d, 0x05b, 0x268, 0x396, 0x1a5, 0x1c3, 0x3f0, 0x10f, 0x33c, 0x35a, 0x169,
182 0x188, 0x3bb, 0x3dd, 0x1ee, 0x311, 0x122, 0x144, 0x377, 0x289, 0x0ba, 0x0dc, 0x2ef, 0x010, 0x223, 0x245, 0x076,
183 0x1b9, 0x38a, 0x3ec, 0x1df, 0x320, 0x113, 0x175, 0x346, 0x2b8, 0x08b, 0x0ed, 0x2de, 0x021, 0x212, 0x274, 0x047,
184 0x1ea, 0x3d9, 0x3bf, 0x18c, 0x373, 0x140, 0x126, 0x315, 0x2eb, 0x0d8, 0x0be, 0x28d, 0x072, 0x241, 0x227, 0x014,
185 0x1db, 0x3e8, 0x38e, 0x1bd, 0x342, 0x171, 0x117, 0x324, 0x2da, 0x0e9, 0x08f, 0x2bc, 0x043, 0x270, 0x216, 0x025,
186 0x14c, 0x37f, 0x319, 0x12a, 0x3d5, 0x1e6, 0x180, 0x3b3, 0x24d, 0x07e, 0x018, 0x22b, 0x0d4, 0x2e7, 0x281, 0x0b2,
187 0x17d, 0x34e, 0x328, 0x11b, 0x3e4, 0x1d7, 0x1b1, 0x382, 0x27c, 0x04f, 0x029, 0x21a, 0x0e5, 0x2d6, 0x2b0, 0x083,
188 0x12e, 0x31d, 0x37b, 0x148, 0x3b7, 0x184, 0x1e2, 0x3d1, 0x22f, 0x01c, 0x07a, 0x249, 0x0b6, 0x285, 0x2e3, 0x0d0,
189 0x11f, 0x32c, 0x34a, 0x179, 0x386, 0x1b5, 0x1d3, 0x3e0, 0x21e, 0x02d, 0x04b, 0x278, 0x087, 0x2b4, 0x2d2, 0x0e1,
192 #define CRC10_INITFCS 0x000 // Initial FCS value
193 #define CRC10_GOODFCS 0x000 // Good final FCS value
194 #define CRC10_FCS(fcs, c) ( (((fcs) << 8) & 0x3ff) ^ crc10_table[((fcs) >> 2) & 0xff] ^ (c))
197 * fcs_compute10 - memcpy and calculate 10 bit CRC across buffer
198 * @sp: pointer to buffer
199 * @len: number of bytes
202 * Perform a memcpy and calculate fcs using ppp 10bit CRC algorithm. Return
205 static __u16 __inline__ fcs_compute10 (unsigned char *sp, int len, __u16 fcs)
207 for (; len-- > 0; fcs = CRC10_FCS (fcs, *sp++));
211 static void safe_read_bulk_callback (struct urb *urb, struct pt_regs *regs)
213 struct usb_serial_port *port = (struct usb_serial_port *) urb->context;
214 struct usb_serial *serial = get_usb_serial (port, __FUNCTION__);
215 unsigned char *data = urb->transfer_buffer;
216 unsigned char length = urb->actual_length;
220 dbg ("%s", __FUNCTION__);
223 dbg ("%s - bad serial pointer, exiting", __FUNCTION__);
228 dbg ("%s - nonzero read bulk status received: %d", __FUNCTION__, urb->status);
232 dbg ("safe_read_bulk_callback length: %d", port->read_urb->actual_length);
236 unsigned char *cp = port->read_urb->transfer_buffer;
237 for (i = 0; i < port->read_urb->actual_length; i++) {
239 printk ("\nru[%02x] ", i);
241 printk ("%02x ", *cp++);
248 if (!(fcs = fcs_compute10 (data, length, CRC10_INITFCS))) {
250 int actual_length = data[length - 2] >> 2;
252 if (actual_length <= (length - 2)) {
254 info ("%s - actual: %d", __FUNCTION__, actual_length);
256 for (i = 0; i < actual_length; i++) {
257 tty_insert_flip_char (port->tty, data[i], 0);
259 tty_flip_buffer_push (port->tty);
261 err ("%s - inconsistent lengths %d:%d", __FUNCTION__,
262 actual_length, length);
265 err ("%s - bad CRC %x", __FUNCTION__, fcs);
268 for (i = 0; i < length; i++) {
269 tty_insert_flip_char (port->tty, data[i], 0);
271 tty_flip_buffer_push (port->tty);
274 /* Continue trying to always read */
275 usb_fill_bulk_urb (urb, serial->dev,
276 usb_rcvbulkpipe (serial->dev, port->bulk_in_endpointAddress),
277 urb->transfer_buffer, urb->transfer_buffer_length,
278 safe_read_bulk_callback, port);
280 if ((result = usb_submit_urb (urb, GFP_ATOMIC))) {
281 err ("%s - failed resubmitting read urb, error %d", __FUNCTION__, result);
285 static int safe_write (struct usb_serial_port *port, int from_user, const unsigned char *buf, int count)
287 struct usb_serial *serial = port->serial;
293 dbg ("safe_write port: %p %d urb: %p count: %d", port, port->number, port->write_urb,
296 if (!port->write_urb) {
297 dbg ("%s - write urb NULL", __FUNCTION__);
301 dbg ("safe_write write_urb: %d transfer_buffer_length",
302 port->write_urb->transfer_buffer_length);
304 if (!port->write_urb->transfer_buffer_length) {
305 dbg ("%s - write urb transfer_buffer_length zero", __FUNCTION__);
309 dbg ("%s - write request of 0 bytes", __FUNCTION__);
312 if (port->write_urb->status == -EINPROGRESS) {
313 dbg ("%s - already writing", __FUNCTION__);
317 packet_length = port->bulk_out_size; // get max packetsize
319 i = packet_length - (safe ? 2 : 0); // get bytes to send
320 count = (count > i) ? i : count;
323 // get the data into the transfer buffer
324 data = port->write_urb->transfer_buffer;
325 memset (data, '0', packet_length);
328 if (copy_from_user (data, buf, count))
331 memcpy (data, buf, count);
339 packet_length = count + 2;
342 data[packet_length - 2] = count << 2;
343 data[packet_length - 1] = 0;
345 // compute fcs and insert into trailer
346 fcs = fcs_compute10 (data, packet_length, CRC10_INITFCS);
347 data[packet_length - 2] |= fcs >> 8;
348 data[packet_length - 1] |= fcs & 0xff;
350 // set length to send
351 port->write_urb->transfer_buffer_length = packet_length;
353 port->write_urb->transfer_buffer_length = count;
356 usb_serial_debug_data (__FILE__, __FUNCTION__, count, port->write_urb->transfer_buffer);
360 unsigned char *cp = port->write_urb->transfer_buffer;
361 for (i = 0; i < port->write_urb->transfer_buffer_length; i++) {
363 printk ("\nsu[%02x] ", i);
365 printk ("%02x ", *cp++);
370 port->write_urb->dev = serial->dev;
371 if ((result = usb_submit_urb (port->write_urb, GFP_KERNEL))) {
372 err ("%s - failed submitting write urb, error %d", __FUNCTION__, result);
375 dbg ("%s urb: %p submitted", __FUNCTION__, port->write_urb);
380 static int safe_write_room (struct usb_serial_port *port)
382 int room = 0; // Default: no room
384 dbg ("%s", __FUNCTION__);
386 if (port->write_urb->status != -EINPROGRESS)
387 room = port->bulk_out_size - (safe ? 2 : 0);
390 dbg ("safe_write_room returns %d", room);
396 static int safe_startup (struct usb_serial *serial)
398 switch (serial->interface->altsetting->desc.bInterfaceProtocol) {
399 case LINEO_SAFESERIAL_CRC:
401 case LINEO_SAFESERIAL_CRC_PADDED:
410 static struct usb_serial_device_type safe_device = {
411 .owner = THIS_MODULE,
413 .id_table = id_table,
414 .num_interrupt_in = NUM_DONT_CARE,
415 .num_bulk_in = NUM_DONT_CARE,
416 .num_bulk_out = NUM_DONT_CARE,
419 .write_room = safe_write_room,
420 .read_bulk_callback = safe_read_bulk_callback,
421 .attach = safe_startup,
424 static int __init safe_init (void)
428 info (DRIVER_VERSION " " DRIVER_AUTHOR);
430 info ("vendor: %x product: %x safe: %d padded: %d\n", vendor, product, safe, padded);
432 // if we have vendor / product parameters patch them into id list
433 if (vendor || product) {
434 info ("vendor: %x product: %x\n", vendor, product);
436 for (i = 0; i < (sizeof (id_table) / sizeof (struct usb_device_id)); i++) {
437 if (!id_table[i].idVendor && !id_table[i].idProduct) {
438 id_table[i].idVendor = vendor;
439 id_table[i].idProduct = product;
445 retval = usb_serial_register(&safe_device);
447 goto failed_usb_serial_register;
448 retval = usb_register(&safe_driver);
450 goto failed_usb_register;
454 usb_serial_deregister(&safe_device);
455 failed_usb_serial_register:
459 static void __exit safe_exit (void)
461 usb_deregister (&safe_driver);
462 usb_serial_deregister (&safe_device);
465 module_init (safe_init);
466 module_exit (safe_exit);