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 unsigned char *data = urb->transfer_buffer;
215 unsigned char length = urb->actual_length;
219 dbg ("%s", __FUNCTION__);
222 dbg ("%s - nonzero read bulk status received: %d", __FUNCTION__, urb->status);
226 dbg ("safe_read_bulk_callback length: %d", port->read_urb->actual_length);
230 unsigned char *cp = port->read_urb->transfer_buffer;
231 for (i = 0; i < port->read_urb->actual_length; i++) {
233 printk ("\nru[%02x] ", i);
235 printk ("%02x ", *cp++);
242 if (!(fcs = fcs_compute10 (data, length, CRC10_INITFCS))) {
244 int actual_length = data[length - 2] >> 2;
246 if (actual_length <= (length - 2)) {
248 info ("%s - actual: %d", __FUNCTION__, actual_length);
250 for (i = 0; i < actual_length; i++) {
251 tty_insert_flip_char (port->tty, data[i], 0);
253 tty_flip_buffer_push (port->tty);
255 err ("%s - inconsistent lengths %d:%d", __FUNCTION__,
256 actual_length, length);
259 err ("%s - bad CRC %x", __FUNCTION__, fcs);
262 for (i = 0; i < length; i++) {
263 tty_insert_flip_char (port->tty, data[i], 0);
265 tty_flip_buffer_push (port->tty);
268 /* Continue trying to always read */
269 usb_fill_bulk_urb (urb, port->serial->dev,
270 usb_rcvbulkpipe (port->serial->dev, port->bulk_in_endpointAddress),
271 urb->transfer_buffer, urb->transfer_buffer_length,
272 safe_read_bulk_callback, port);
274 if ((result = usb_submit_urb (urb, GFP_ATOMIC))) {
275 err ("%s - failed resubmitting read urb, error %d", __FUNCTION__, result);
279 static int safe_write (struct usb_serial_port *port, int from_user, const unsigned char *buf, int count)
286 dbg ("safe_write port: %p %d urb: %p count: %d", port, port->number, port->write_urb,
289 if (!port->write_urb) {
290 dbg ("%s - write urb NULL", __FUNCTION__);
294 dbg ("safe_write write_urb: %d transfer_buffer_length",
295 port->write_urb->transfer_buffer_length);
297 if (!port->write_urb->transfer_buffer_length) {
298 dbg ("%s - write urb transfer_buffer_length zero", __FUNCTION__);
302 dbg ("%s - write request of 0 bytes", __FUNCTION__);
305 if (port->write_urb->status == -EINPROGRESS) {
306 dbg ("%s - already writing", __FUNCTION__);
310 packet_length = port->bulk_out_size; // get max packetsize
312 i = packet_length - (safe ? 2 : 0); // get bytes to send
313 count = (count > i) ? i : count;
316 // get the data into the transfer buffer
317 data = port->write_urb->transfer_buffer;
318 memset (data, '0', packet_length);
321 if (copy_from_user (data, buf, count))
324 memcpy (data, buf, count);
332 packet_length = count + 2;
335 data[packet_length - 2] = count << 2;
336 data[packet_length - 1] = 0;
338 // compute fcs and insert into trailer
339 fcs = fcs_compute10 (data, packet_length, CRC10_INITFCS);
340 data[packet_length - 2] |= fcs >> 8;
341 data[packet_length - 1] |= fcs & 0xff;
343 // set length to send
344 port->write_urb->transfer_buffer_length = packet_length;
346 port->write_urb->transfer_buffer_length = count;
349 usb_serial_debug_data (__FILE__, __FUNCTION__, count, port->write_urb->transfer_buffer);
353 unsigned char *cp = port->write_urb->transfer_buffer;
354 for (i = 0; i < port->write_urb->transfer_buffer_length; i++) {
356 printk ("\nsu[%02x] ", i);
358 printk ("%02x ", *cp++);
363 port->write_urb->dev = port->serial->dev;
364 if ((result = usb_submit_urb (port->write_urb, GFP_KERNEL))) {
365 err ("%s - failed submitting write urb, error %d", __FUNCTION__, result);
368 dbg ("%s urb: %p submitted", __FUNCTION__, port->write_urb);
373 static int safe_write_room (struct usb_serial_port *port)
375 int room = 0; // Default: no room
377 dbg ("%s", __FUNCTION__);
379 if (port->write_urb->status != -EINPROGRESS)
380 room = port->bulk_out_size - (safe ? 2 : 0);
383 dbg ("safe_write_room returns %d", room);
389 static int safe_startup (struct usb_serial *serial)
391 switch (serial->interface->cur_altsetting->desc.bInterfaceProtocol) {
392 case LINEO_SAFESERIAL_CRC:
394 case LINEO_SAFESERIAL_CRC_PADDED:
403 static struct usb_serial_device_type safe_device = {
404 .owner = THIS_MODULE,
406 .id_table = id_table,
407 .num_interrupt_in = NUM_DONT_CARE,
408 .num_bulk_in = NUM_DONT_CARE,
409 .num_bulk_out = NUM_DONT_CARE,
412 .write_room = safe_write_room,
413 .read_bulk_callback = safe_read_bulk_callback,
414 .attach = safe_startup,
417 static int __init safe_init (void)
421 info (DRIVER_VERSION " " DRIVER_AUTHOR);
423 info ("vendor: %x product: %x safe: %d padded: %d\n", vendor, product, safe, padded);
425 // if we have vendor / product parameters patch them into id list
426 if (vendor || product) {
427 info ("vendor: %x product: %x\n", vendor, product);
429 for (i = 0; i < (sizeof (id_table) / sizeof (struct usb_device_id)); i++) {
430 if (!id_table[i].idVendor && !id_table[i].idProduct) {
431 id_table[i].idVendor = vendor;
432 id_table[i].idProduct = product;
438 retval = usb_serial_register(&safe_device);
440 goto failed_usb_serial_register;
441 retval = usb_register(&safe_driver);
443 goto failed_usb_register;
447 usb_serial_deregister(&safe_device);
448 failed_usb_serial_register:
452 static void __exit safe_exit (void)
454 usb_deregister (&safe_driver);
455 usb_serial_deregister (&safe_device);
458 module_init (safe_init);
459 module_exit (safe_exit);