1 /* 2 * Safe Encapsulated USB Serial Driver 3 * 4 * Copyright (C) 2001 Lineo 5 * Copyright (C) 2001 Hewlett-Packard 6 * 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. 11 * 12 * By: 13 * Stuart Lynne <sl@lineo.com>, Tom Rushworth <tbr@lineo.com> 14 */ 15 16 /* 17 * The encapsultaion is designed to overcome difficulties with some USB hardware. 18 * 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. 23 * 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. 27 * 28 * Because in this case the sender and receiver are the class and function drivers 29 * there is now end to end protection. 30 * 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. 34 * 35 * Assuming a packetsize of N: 36 * 37 * 0..N-2 data and optional padding 38 * 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 42 * 43 * 44 * | Data Length | 10 bit CRC | 45 * + 7 . 6 . 5 . 4 . 3 . 2 . 1 . 0 | 7 . 6 . 5 . 4 . 3 . 2 . 1 . 0 + 46 * 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. 49 * 50 * When received a 10 bit CRC is computed over the entire frame including the trailer 51 * and should be equal to zero. 52 * 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 55 * encapsulation. 56 * 57 * See linux/drivers/usbd/serial_fd for a device function driver 58 * implementation of this. 59 * 60 */ 61 62 63 #include <linux/kernel.h> 64 #include <linux/errno.h> 65 #include <linux/init.h> 66 #include <linux/slab.h> 67 #include <linux/tty.h> 68 #include <linux/tty_driver.h> 69 #include <linux/tty_flip.h> 70 #include <linux/module.h> 71 #include <linux/spinlock.h> 72 #include <asm/uaccess.h> 73 #include <linux/usb.h> 74 #include <linux/usb/serial.h> 75 76 77 #ifndef CONFIG_USB_SAFE_PADDED 78 #define CONFIG_USB_SAFE_PADDED 0 79 #endif 80 81 static int debug; 82 static int safe = 1; 83 static int padded = CONFIG_USB_SAFE_PADDED; 84 85 #define DRIVER_VERSION "v0.0b" 86 #define DRIVER_AUTHOR "sl@lineo.com, tbr@lineo.com" 87 #define DRIVER_DESC "USB Safe Encapsulated Serial" 88 89 MODULE_AUTHOR (DRIVER_AUTHOR); 90 MODULE_DESCRIPTION (DRIVER_DESC); 91 MODULE_LICENSE("GPL"); 92 93 #if defined(CONFIG_USBD_SAFE_SERIAL_VENDOR) && !defined(CONFIG_USBD_SAFE_SERIAL_PRODUCT) 94 #error "SAFE_SERIAL_VENDOR defined without SAFE_SERIAL_PRODUCT" 95 #endif 96 97 #if ! defined(CONFIG_USBD_SAFE_SERIAL_VENDOR) 98 static __u16 vendor; // no default 99 static __u16 product; // no default 100 module_param(vendor, ushort, 0); 101 MODULE_PARM_DESC(vendor, "User specified USB idVendor (required)"); 102 module_param(product, ushort, 0); 103 MODULE_PARM_DESC(product, "User specified USB idProduct (required)"); 104 #endif 105 106 module_param(debug, bool, S_IRUGO | S_IWUSR); 107 MODULE_PARM_DESC(debug, "Debug enabled or not"); 108 109 module_param(safe, bool, 0); 110 MODULE_PARM_DESC(safe, "Turn Safe Encapsulation On/Off"); 111 112 module_param(padded, bool, 0); 113 MODULE_PARM_DESC(padded, "Pad to full wMaxPacketSize On/Off"); 114 115 #define CDC_DEVICE_CLASS 0x02 116 117 #define CDC_INTERFACE_CLASS 0x02 118 #define CDC_INTERFACE_SUBCLASS 0x06 119 120 #define LINEO_INTERFACE_CLASS 0xff 121 122 #define LINEO_INTERFACE_SUBCLASS_SAFENET 0x01 123 #define LINEO_SAFENET_CRC 0x01 124 #define LINEO_SAFENET_CRC_PADDED 0x02 125 126 #define LINEO_INTERFACE_SUBCLASS_SAFESERIAL 0x02 127 #define LINEO_SAFESERIAL_CRC 0x01 128 #define LINEO_SAFESERIAL_CRC_PADDED 0x02 129 130 131 #define MY_USB_DEVICE(vend,prod,dc,ic,isc) \ 132 .match_flags = USB_DEVICE_ID_MATCH_DEVICE | USB_DEVICE_ID_MATCH_DEV_CLASS | \ 133 USB_DEVICE_ID_MATCH_INT_CLASS | USB_DEVICE_ID_MATCH_INT_SUBCLASS, \ 134 .idVendor = (vend), \ 135 .idProduct = (prod),\ 136 .bDeviceClass = (dc),\ 137 .bInterfaceClass = (ic), \ 138 .bInterfaceSubClass = (isc), 139 140 static struct usb_device_id id_table[] = { 141 {MY_USB_DEVICE (0x49f, 0xffff, CDC_DEVICE_CLASS, LINEO_INTERFACE_CLASS, LINEO_INTERFACE_SUBCLASS_SAFESERIAL)}, // Itsy 142 {MY_USB_DEVICE (0x3f0, 0x2101, CDC_DEVICE_CLASS, LINEO_INTERFACE_CLASS, LINEO_INTERFACE_SUBCLASS_SAFESERIAL)}, // Calypso 143 {MY_USB_DEVICE (0x4dd, 0x8001, CDC_DEVICE_CLASS, LINEO_INTERFACE_CLASS, LINEO_INTERFACE_SUBCLASS_SAFESERIAL)}, // Iris 144 {MY_USB_DEVICE (0x4dd, 0x8002, CDC_DEVICE_CLASS, LINEO_INTERFACE_CLASS, LINEO_INTERFACE_SUBCLASS_SAFESERIAL)}, // Collie 145 {MY_USB_DEVICE (0x4dd, 0x8003, CDC_DEVICE_CLASS, LINEO_INTERFACE_CLASS, LINEO_INTERFACE_SUBCLASS_SAFESERIAL)}, // Collie 146 {MY_USB_DEVICE (0x4dd, 0x8004, CDC_DEVICE_CLASS, LINEO_INTERFACE_CLASS, LINEO_INTERFACE_SUBCLASS_SAFESERIAL)}, // Collie 147 {MY_USB_DEVICE (0x5f9, 0xffff, CDC_DEVICE_CLASS, LINEO_INTERFACE_CLASS, LINEO_INTERFACE_SUBCLASS_SAFESERIAL)}, // Sharp tmp 148 #if defined(CONFIG_USB_SAFE_SERIAL_VENDOR) 149 {MY_USB_DEVICE 150 (CONFIG_USB_SAFE_SERIAL_VENDOR, CONFIG_USB_SAFE_SERIAL_PRODUCT, CDC_DEVICE_CLASS, 151 LINEO_INTERFACE_CLASS, LINEO_INTERFACE_SUBCLASS_SAFESERIAL)}, 152 #endif 153 // extra null entry for module 154 // vendor/produc parameters 155 {MY_USB_DEVICE (0, 0, CDC_DEVICE_CLASS, LINEO_INTERFACE_CLASS, LINEO_INTERFACE_SUBCLASS_SAFESERIAL)}, 156 {} // terminating entry 157 }; 158 159 MODULE_DEVICE_TABLE (usb, id_table); 160 161 static struct usb_driver safe_driver = { 162 .name = "safe_serial", 163 .probe = usb_serial_probe, 164 .disconnect = usb_serial_disconnect, 165 .id_table = id_table, 166 .no_dynamic_id = 1, 167 }; 168 169 static const __u16 crc10_table[256] = { 170 0x000, 0x233, 0x255, 0x066, 0x299, 0x0aa, 0x0cc, 0x2ff, 0x301, 0x132, 0x154, 0x367, 0x198, 0x3ab, 0x3cd, 0x1fe, 171 0x031, 0x202, 0x264, 0x057, 0x2a8, 0x09b, 0x0fd, 0x2ce, 0x330, 0x103, 0x165, 0x356, 0x1a9, 0x39a, 0x3fc, 0x1cf, 172 0x062, 0x251, 0x237, 0x004, 0x2fb, 0x0c8, 0x0ae, 0x29d, 0x363, 0x150, 0x136, 0x305, 0x1fa, 0x3c9, 0x3af, 0x19c, 173 0x053, 0x260, 0x206, 0x035, 0x2ca, 0x0f9, 0x09f, 0x2ac, 0x352, 0x161, 0x107, 0x334, 0x1cb, 0x3f8, 0x39e, 0x1ad, 174 0x0c4, 0x2f7, 0x291, 0x0a2, 0x25d, 0x06e, 0x008, 0x23b, 0x3c5, 0x1f6, 0x190, 0x3a3, 0x15c, 0x36f, 0x309, 0x13a, 175 0x0f5, 0x2c6, 0x2a0, 0x093, 0x26c, 0x05f, 0x039, 0x20a, 0x3f4, 0x1c7, 0x1a1, 0x392, 0x16d, 0x35e, 0x338, 0x10b, 176 0x0a6, 0x295, 0x2f3, 0x0c0, 0x23f, 0x00c, 0x06a, 0x259, 0x3a7, 0x194, 0x1f2, 0x3c1, 0x13e, 0x30d, 0x36b, 0x158, 177 0x097, 0x2a4, 0x2c2, 0x0f1, 0x20e, 0x03d, 0x05b, 0x268, 0x396, 0x1a5, 0x1c3, 0x3f0, 0x10f, 0x33c, 0x35a, 0x169, 178 0x188, 0x3bb, 0x3dd, 0x1ee, 0x311, 0x122, 0x144, 0x377, 0x289, 0x0ba, 0x0dc, 0x2ef, 0x010, 0x223, 0x245, 0x076, 179 0x1b9, 0x38a, 0x3ec, 0x1df, 0x320, 0x113, 0x175, 0x346, 0x2b8, 0x08b, 0x0ed, 0x2de, 0x021, 0x212, 0x274, 0x047, 180 0x1ea, 0x3d9, 0x3bf, 0x18c, 0x373, 0x140, 0x126, 0x315, 0x2eb, 0x0d8, 0x0be, 0x28d, 0x072, 0x241, 0x227, 0x014, 181 0x1db, 0x3e8, 0x38e, 0x1bd, 0x342, 0x171, 0x117, 0x324, 0x2da, 0x0e9, 0x08f, 0x2bc, 0x043, 0x270, 0x216, 0x025, 182 0x14c, 0x37f, 0x319, 0x12a, 0x3d5, 0x1e6, 0x180, 0x3b3, 0x24d, 0x07e, 0x018, 0x22b, 0x0d4, 0x2e7, 0x281, 0x0b2, 183 0x17d, 0x34e, 0x328, 0x11b, 0x3e4, 0x1d7, 0x1b1, 0x382, 0x27c, 0x04f, 0x029, 0x21a, 0x0e5, 0x2d6, 0x2b0, 0x083, 184 0x12e, 0x31d, 0x37b, 0x148, 0x3b7, 0x184, 0x1e2, 0x3d1, 0x22f, 0x01c, 0x07a, 0x249, 0x0b6, 0x285, 0x2e3, 0x0d0, 185 0x11f, 0x32c, 0x34a, 0x179, 0x386, 0x1b5, 0x1d3, 0x3e0, 0x21e, 0x02d, 0x04b, 0x278, 0x087, 0x2b4, 0x2d2, 0x0e1, 186 }; 187 188 #define CRC10_INITFCS 0x000 // Initial FCS value 189 #define CRC10_GOODFCS 0x000 // Good final FCS value 190 #define CRC10_FCS(fcs, c) ( (((fcs) << 8) & 0x3ff) ^ crc10_table[((fcs) >> 2) & 0xff] ^ (c)) 191 192 /** 193 * fcs_compute10 - memcpy and calculate 10 bit CRC across buffer 194 * @sp: pointer to buffer 195 * @len: number of bytes 196 * @fcs: starting FCS 197 * 198 * Perform a memcpy and calculate fcs using ppp 10bit CRC algorithm. Return 199 * new 10 bit FCS. 200 */ 201 static __u16 __inline__ fcs_compute10 (unsigned char *sp, int len, __u16 fcs) 202 { 203 for (; len-- > 0; fcs = CRC10_FCS (fcs, *sp++)); 204 return fcs; 205 } 206 207 static void safe_read_bulk_callback (struct urb *urb) 208 { 209 struct usb_serial_port *port = (struct usb_serial_port *) urb->context; 210 unsigned char *data = urb->transfer_buffer; 211 unsigned char length = urb->actual_length; 212 int i; 213 int result; 214 int status = urb->status; 215 216 dbg ("%s", __FUNCTION__); 217 218 if (status) { 219 dbg("%s - nonzero read bulk status received: %d", 220 __FUNCTION__, status); 221 return; 222 } 223 224 dbg ("safe_read_bulk_callback length: %d", port->read_urb->actual_length); 225 #ifdef ECHO_RCV 226 { 227 int i; 228 unsigned char *cp = port->read_urb->transfer_buffer; 229 for (i = 0; i < port->read_urb->actual_length; i++) { 230 if ((i % 32) == 0) { 231 printk ("\nru[%02x] ", i); 232 } 233 printk ("%02x ", *cp++); 234 } 235 printk ("\n"); 236 } 237 #endif 238 if (safe) { 239 __u16 fcs; 240 if (!(fcs = fcs_compute10 (data, length, CRC10_INITFCS))) { 241 242 int actual_length = data[length - 2] >> 2; 243 244 if (actual_length <= (length - 2)) { 245 246 info ("%s - actual: %d", __FUNCTION__, actual_length); 247 248 for (i = 0; i < actual_length; i++) { 249 tty_insert_flip_char (port->tty, data[i], 0); 250 } 251 tty_flip_buffer_push (port->tty); 252 } else { 253 err ("%s - inconsistent lengths %d:%d", __FUNCTION__, 254 actual_length, length); 255 } 256 } else { 257 err ("%s - bad CRC %x", __FUNCTION__, fcs); 258 } 259 } else { 260 for (i = 0; i < length; i++) { 261 tty_insert_flip_char (port->tty, data[i], 0); 262 } 263 tty_flip_buffer_push (port->tty); 264 } 265 266 /* Continue trying to always read */ 267 usb_fill_bulk_urb (urb, port->serial->dev, 268 usb_rcvbulkpipe (port->serial->dev, port->bulk_in_endpointAddress), 269 urb->transfer_buffer, urb->transfer_buffer_length, 270 safe_read_bulk_callback, port); 271 272 if ((result = usb_submit_urb (urb, GFP_ATOMIC))) { 273 err ("%s - failed resubmitting read urb, error %d", __FUNCTION__, result); 274 } 275 } 276 277 static int safe_write (struct usb_serial_port *port, const unsigned char *buf, int count) 278 { 279 unsigned char *data; 280 int result; 281 int i; 282 int packet_length; 283 284 dbg ("safe_write port: %p %d urb: %p count: %d", port, port->number, port->write_urb, 285 count); 286 287 if (!port->write_urb) { 288 dbg ("%s - write urb NULL", __FUNCTION__); 289 return (0); 290 } 291 292 dbg ("safe_write write_urb: %d transfer_buffer_length", 293 port->write_urb->transfer_buffer_length); 294 295 if (!port->write_urb->transfer_buffer_length) { 296 dbg ("%s - write urb transfer_buffer_length zero", __FUNCTION__); 297 return (0); 298 } 299 if (count == 0) { 300 dbg ("%s - write request of 0 bytes", __FUNCTION__); 301 return (0); 302 } 303 spin_lock_bh(&port->lock); 304 if (port->write_urb_busy) { 305 spin_unlock_bh(&port->lock); 306 dbg("%s - already writing", __FUNCTION__); 307 return 0; 308 } 309 port->write_urb_busy = 1; 310 spin_unlock_bh(&port->lock); 311 312 packet_length = port->bulk_out_size; // get max packetsize 313 314 i = packet_length - (safe ? 2 : 0); // get bytes to send 315 count = (count > i) ? i : count; 316 317 318 // get the data into the transfer buffer 319 data = port->write_urb->transfer_buffer; 320 memset (data, '0', packet_length); 321 322 memcpy (data, buf, count); 323 324 if (safe) { 325 __u16 fcs; 326 327 // pad if necessary 328 if (!padded) { 329 packet_length = count + 2; 330 } 331 // set count 332 data[packet_length - 2] = count << 2; 333 data[packet_length - 1] = 0; 334 335 // compute fcs and insert into trailer 336 fcs = fcs_compute10 (data, packet_length, CRC10_INITFCS); 337 data[packet_length - 2] |= fcs >> 8; 338 data[packet_length - 1] |= fcs & 0xff; 339 340 // set length to send 341 port->write_urb->transfer_buffer_length = packet_length; 342 } else { 343 port->write_urb->transfer_buffer_length = count; 344 } 345 346 usb_serial_debug_data(debug, &port->dev, __FUNCTION__, count, port->write_urb->transfer_buffer); 347 #ifdef ECHO_TX 348 { 349 int i; 350 unsigned char *cp = port->write_urb->transfer_buffer; 351 for (i = 0; i < port->write_urb->transfer_buffer_length; i++) { 352 if ((i % 32) == 0) { 353 printk ("\nsu[%02x] ", i); 354 } 355 printk ("%02x ", *cp++); 356 } 357 printk ("\n"); 358 } 359 #endif 360 port->write_urb->dev = port->serial->dev; 361 if ((result = usb_submit_urb (port->write_urb, GFP_KERNEL))) { 362 port->write_urb_busy = 0; 363 err ("%s - failed submitting write urb, error %d", __FUNCTION__, result); 364 return 0; 365 } 366 dbg ("%s urb: %p submitted", __FUNCTION__, port->write_urb); 367 368 return (count); 369 } 370 371 static int safe_write_room (struct usb_serial_port *port) 372 { 373 int room = 0; // Default: no room 374 375 dbg ("%s", __FUNCTION__); 376 377 if (port->write_urb_busy) 378 room = port->bulk_out_size - (safe ? 2 : 0); 379 380 if (room) { 381 dbg ("safe_write_room returns %d", room); 382 } 383 384 return (room); 385 } 386 387 static int safe_startup (struct usb_serial *serial) 388 { 389 switch (serial->interface->cur_altsetting->desc.bInterfaceProtocol) { 390 case LINEO_SAFESERIAL_CRC: 391 break; 392 case LINEO_SAFESERIAL_CRC_PADDED: 393 padded = 1; 394 break; 395 default: 396 return -EINVAL; 397 } 398 return 0; 399 } 400 401 static struct usb_serial_driver safe_device = { 402 .driver = { 403 .owner = THIS_MODULE, 404 .name = "safe_serial", 405 }, 406 .id_table = id_table, 407 .usb_driver = &safe_driver, 408 .num_interrupt_in = NUM_DONT_CARE, 409 .num_bulk_in = NUM_DONT_CARE, 410 .num_bulk_out = NUM_DONT_CARE, 411 .num_ports = 1, 412 .write = safe_write, 413 .write_room = safe_write_room, 414 .read_bulk_callback = safe_read_bulk_callback, 415 .attach = safe_startup, 416 }; 417 418 static int __init safe_init (void) 419 { 420 int i, retval; 421 422 info (DRIVER_VERSION " " DRIVER_AUTHOR); 423 info (DRIVER_DESC); 424 info ("vendor: %x product: %x safe: %d padded: %d\n", vendor, product, safe, padded); 425 426 // if we have vendor / product parameters patch them into id list 427 if (vendor || product) { 428 info ("vendor: %x product: %x\n", vendor, product); 429 430 for (i = 0; i < ARRAY_SIZE(id_table); i++) { 431 if (!id_table[i].idVendor && !id_table[i].idProduct) { 432 id_table[i].idVendor = vendor; 433 id_table[i].idProduct = product; 434 break; 435 } 436 } 437 } 438 439 retval = usb_serial_register(&safe_device); 440 if (retval) 441 goto failed_usb_serial_register; 442 retval = usb_register(&safe_driver); 443 if (retval) 444 goto failed_usb_register; 445 446 return 0; 447 failed_usb_register: 448 usb_serial_deregister(&safe_device); 449 failed_usb_serial_register: 450 return retval; 451 } 452 453 static void __exit safe_exit (void) 454 { 455 usb_deregister (&safe_driver); 456 usb_serial_deregister (&safe_device); 457 } 458 459 module_init (safe_init); 460 module_exit (safe_exit); 461