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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 | * |
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 |
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 |
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> |
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 | |
79 | ||
3aec6e26 RD |
80 | #ifndef CONFIG_USB_SERIAL_SAFE_PADDED |
81 | #define CONFIG_USB_SERIAL_SAFE_PADDED 0 | |
1da177e4 LT |
82 | #endif |
83 | ||
84 | static int debug; | |
85 | static int safe = 1; | |
3aec6e26 | 86 | static int padded = CONFIG_USB_SERIAL_SAFE_PADDED; |
1da177e4 | 87 | |
241c80ea JH |
88 | #define DRIVER_VERSION "v0.1" |
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" |
91 | ||
43c8f435 AC |
92 | MODULE_AUTHOR(DRIVER_AUTHOR); |
93 | MODULE_DESCRIPTION(DRIVER_DESC); | |
1da177e4 LT |
94 | MODULE_LICENSE("GPL"); |
95 | ||
43c8f435 AC |
96 | static __u16 vendor; /* no default */ |
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 | |
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 | }; |
151 | ||
43c8f435 | 152 | MODULE_DEVICE_TABLE(usb, id_table); |
1da177e4 LT |
153 | |
154 | static struct usb_driver safe_driver = { | |
1da177e4 LT |
155 | .name = "safe_serial", |
156 | .probe = usb_serial_probe, | |
157 | .disconnect = usb_serial_disconnect, | |
158 | .id_table = id_table, | |
ba9dc657 | 159 | .no_dynamic_id = 1, |
1da177e4 LT |
160 | }; |
161 | ||
4c4c9432 | 162 | static const __u16 crc10_table[256] = { |
43c8f435 AC |
163 | 0x000, 0x233, 0x255, 0x066, 0x299, 0x0aa, 0x0cc, 0x2ff, |
164 | 0x301, 0x132, 0x154, 0x367, 0x198, 0x3ab, 0x3cd, 0x1fe, | |
165 | 0x031, 0x202, 0x264, 0x057, 0x2a8, 0x09b, 0x0fd, 0x2ce, | |
166 | 0x330, 0x103, 0x165, 0x356, 0x1a9, 0x39a, 0x3fc, 0x1cf, | |
167 | 0x062, 0x251, 0x237, 0x004, 0x2fb, 0x0c8, 0x0ae, 0x29d, | |
168 | 0x363, 0x150, 0x136, 0x305, 0x1fa, 0x3c9, 0x3af, 0x19c, | |
169 | 0x053, 0x260, 0x206, 0x035, 0x2ca, 0x0f9, 0x09f, 0x2ac, | |
170 | 0x352, 0x161, 0x107, 0x334, 0x1cb, 0x3f8, 0x39e, 0x1ad, | |
171 | 0x0c4, 0x2f7, 0x291, 0x0a2, 0x25d, 0x06e, 0x008, 0x23b, | |
172 | 0x3c5, 0x1f6, 0x190, 0x3a3, 0x15c, 0x36f, 0x309, 0x13a, | |
173 | 0x0f5, 0x2c6, 0x2a0, 0x093, 0x26c, 0x05f, 0x039, 0x20a, | |
174 | 0x3f4, 0x1c7, 0x1a1, 0x392, 0x16d, 0x35e, 0x338, 0x10b, | |
175 | 0x0a6, 0x295, 0x2f3, 0x0c0, 0x23f, 0x00c, 0x06a, 0x259, | |
176 | 0x3a7, 0x194, 0x1f2, 0x3c1, 0x13e, 0x30d, 0x36b, 0x158, | |
177 | 0x097, 0x2a4, 0x2c2, 0x0f1, 0x20e, 0x03d, 0x05b, 0x268, | |
178 | 0x396, 0x1a5, 0x1c3, 0x3f0, 0x10f, 0x33c, 0x35a, 0x169, | |
179 | 0x188, 0x3bb, 0x3dd, 0x1ee, 0x311, 0x122, 0x144, 0x377, | |
180 | 0x289, 0x0ba, 0x0dc, 0x2ef, 0x010, 0x223, 0x245, 0x076, | |
181 | 0x1b9, 0x38a, 0x3ec, 0x1df, 0x320, 0x113, 0x175, 0x346, | |
182 | 0x2b8, 0x08b, 0x0ed, 0x2de, 0x021, 0x212, 0x274, 0x047, | |
183 | 0x1ea, 0x3d9, 0x3bf, 0x18c, 0x373, 0x140, 0x126, 0x315, | |
184 | 0x2eb, 0x0d8, 0x0be, 0x28d, 0x072, 0x241, 0x227, 0x014, | |
185 | 0x1db, 0x3e8, 0x38e, 0x1bd, 0x342, 0x171, 0x117, 0x324, | |
186 | 0x2da, 0x0e9, 0x08f, 0x2bc, 0x043, 0x270, 0x216, 0x025, | |
187 | 0x14c, 0x37f, 0x319, 0x12a, 0x3d5, 0x1e6, 0x180, 0x3b3, | |
188 | 0x24d, 0x07e, 0x018, 0x22b, 0x0d4, 0x2e7, 0x281, 0x0b2, | |
189 | 0x17d, 0x34e, 0x328, 0x11b, 0x3e4, 0x1d7, 0x1b1, 0x382, | |
190 | 0x27c, 0x04f, 0x029, 0x21a, 0x0e5, 0x2d6, 0x2b0, 0x083, | |
191 | 0x12e, 0x31d, 0x37b, 0x148, 0x3b7, 0x184, 0x1e2, 0x3d1, | |
192 | 0x22f, 0x01c, 0x07a, 0x249, 0x0b6, 0x285, 0x2e3, 0x0d0, | |
193 | 0x11f, 0x32c, 0x34a, 0x179, 0x386, 0x1b5, 0x1d3, 0x3e0, | |
194 | 0x21e, 0x02d, 0x04b, 0x278, 0x087, 0x2b4, 0x2d2, 0x0e1, | |
1da177e4 LT |
195 | }; |
196 | ||
43c8f435 AC |
197 | #define CRC10_INITFCS 0x000 /* Initial FCS value */ |
198 | #define CRC10_GOODFCS 0x000 /* Good final FCS value */ | |
199 | #define CRC10_FCS(fcs, c) ((((fcs) << 8) & 0x3ff) ^ crc10_table[((fcs) >> 2) & 0xff] ^ (c)) | |
1da177e4 | 200 | |
43c8f435 | 201 | /** |
1da177e4 LT |
202 | * fcs_compute10 - memcpy and calculate 10 bit CRC across buffer |
203 | * @sp: pointer to buffer | |
204 | * @len: number of bytes | |
205 | * @fcs: starting FCS | |
206 | * | |
207 | * Perform a memcpy and calculate fcs using ppp 10bit CRC algorithm. Return | |
208 | * new 10 bit FCS. | |
209 | */ | |
43c8f435 | 210 | static __u16 __inline__ fcs_compute10(unsigned char *sp, int len, __u16 fcs) |
1da177e4 | 211 | { |
43c8f435 | 212 | for (; len-- > 0; fcs = CRC10_FCS(fcs, *sp++)); |
1da177e4 LT |
213 | return fcs; |
214 | } | |
215 | ||
12e2e52c | 216 | static void safe_process_read_urb(struct urb *urb) |
1da177e4 | 217 | { |
12e2e52c | 218 | struct usb_serial_port *port = urb->context; |
1da177e4 LT |
219 | unsigned char *data = urb->transfer_buffer; |
220 | unsigned char length = urb->actual_length; | |
6d1bf48e | 221 | int actual_length; |
4a90f09b | 222 | struct tty_struct *tty; |
6d1bf48e | 223 | __u16 fcs; |
1da177e4 | 224 | |
12e2e52c | 225 | if (!length) |
1da177e4 | 226 | return; |
1da177e4 | 227 | |
4a90f09b | 228 | tty = tty_port_tty_get(&port->port); |
12e2e52c JH |
229 | if (!tty) |
230 | return; | |
231 | ||
6d1bf48e JH |
232 | if (!safe) |
233 | goto out; | |
234 | ||
235 | fcs = fcs_compute10(data, length, CRC10_INITFCS); | |
236 | if (fcs) { | |
237 | dev_err(&port->dev, "%s - bad CRC %x\n", __func__, fcs); | |
238 | goto err; | |
1da177e4 LT |
239 | } |
240 | ||
6d1bf48e JH |
241 | actual_length = data[length - 2] >> 2; |
242 | if (actual_length > (length - 2)) { | |
243 | dev_err(&port->dev, "%s - inconsistent lengths %d:%d\n", | |
244 | __func__, actual_length, length); | |
245 | goto err; | |
246 | } | |
247 | dev_info(&urb->dev->dev, "%s - actual: %d\n", __func__, actual_length); | |
248 | length = actual_length; | |
249 | out: | |
250 | tty_insert_flip_string(tty, data, length); | |
251 | tty_flip_buffer_push(tty); | |
252 | err: | |
12e2e52c | 253 | tty_kref_put(tty); |
1da177e4 LT |
254 | } |
255 | ||
241c80ea JH |
256 | static int safe_prepare_write_buffer(struct usb_serial_port *port, |
257 | void *dest, size_t size) | |
1da177e4 | 258 | { |
241c80ea JH |
259 | unsigned char *buf = dest; |
260 | int count; | |
261 | int trailer_len; | |
262 | int pkt_len; | |
263 | __u16 fcs; | |
264 | ||
265 | trailer_len = safe ? 2 : 0; | |
266 | ||
267 | count = kfifo_out_locked(&port->write_fifo, buf, size - trailer_len, | |
268 | &port->lock); | |
269 | if (!safe) | |
270 | return count; | |
271 | ||
272 | /* pad if necessary */ | |
273 | if (padded) { | |
274 | pkt_len = size; | |
275 | memset(buf + count, '0', pkt_len - count - trailer_len); | |
1da177e4 | 276 | } else { |
241c80ea | 277 | pkt_len = count + trailer_len; |
1da177e4 | 278 | } |
1da177e4 | 279 | |
241c80ea JH |
280 | /* set count */ |
281 | buf[pkt_len - 2] = count << 2; | |
282 | buf[pkt_len - 1] = 0; | |
1da177e4 | 283 | |
241c80ea JH |
284 | /* compute fcs and insert into trailer */ |
285 | fcs = fcs_compute10(buf, pkt_len, CRC10_INITFCS); | |
286 | buf[pkt_len - 2] |= fcs >> 8; | |
287 | buf[pkt_len - 1] |= fcs & 0xff; | |
1da177e4 | 288 | |
241c80ea | 289 | return pkt_len; |
1da177e4 LT |
290 | } |
291 | ||
43c8f435 | 292 | static int safe_startup(struct usb_serial *serial) |
1da177e4 LT |
293 | { |
294 | switch (serial->interface->cur_altsetting->desc.bInterfaceProtocol) { | |
295 | case LINEO_SAFESERIAL_CRC: | |
296 | break; | |
297 | case LINEO_SAFESERIAL_CRC_PADDED: | |
298 | padded = 1; | |
299 | break; | |
300 | default: | |
301 | return -EINVAL; | |
302 | } | |
303 | return 0; | |
304 | } | |
305 | ||
ea65370d | 306 | static struct usb_serial_driver safe_device = { |
18fcac35 GKH |
307 | .driver = { |
308 | .owner = THIS_MODULE, | |
269bda1c | 309 | .name = "safe_serial", |
18fcac35 | 310 | }, |
1da177e4 | 311 | .id_table = id_table, |
d9b1b787 | 312 | .usb_driver = &safe_driver, |
1da177e4 | 313 | .num_ports = 1, |
12e2e52c | 314 | .process_read_urb = safe_process_read_urb, |
241c80ea | 315 | .prepare_write_buffer = safe_prepare_write_buffer, |
1da177e4 LT |
316 | .attach = safe_startup, |
317 | }; | |
318 | ||
43c8f435 | 319 | static int __init safe_init(void) |
1da177e4 LT |
320 | { |
321 | int i, retval; | |
322 | ||
c197a8db GKH |
323 | printk(KERN_INFO KBUILD_MODNAME ": " DRIVER_VERSION ":" |
324 | DRIVER_DESC "\n"); | |
1da177e4 | 325 | |
43c8f435 | 326 | /* if we have vendor / product parameters patch them into id list */ |
1da177e4 | 327 | if (vendor || product) { |
c197a8db GKH |
328 | printk(KERN_INFO KBUILD_MODNAME ": vendor: %x product: %x\n", |
329 | vendor, product); | |
1da177e4 | 330 | |
52950ed4 | 331 | for (i = 0; i < ARRAY_SIZE(id_table); i++) { |
1da177e4 LT |
332 | if (!id_table[i].idVendor && !id_table[i].idProduct) { |
333 | id_table[i].idVendor = vendor; | |
334 | id_table[i].idProduct = product; | |
335 | break; | |
336 | } | |
337 | } | |
338 | } | |
339 | ||
340 | retval = usb_serial_register(&safe_device); | |
341 | if (retval) | |
342 | goto failed_usb_serial_register; | |
343 | retval = usb_register(&safe_driver); | |
344 | if (retval) | |
345 | goto failed_usb_register; | |
346 | ||
347 | return 0; | |
348 | failed_usb_register: | |
349 | usb_serial_deregister(&safe_device); | |
350 | failed_usb_serial_register: | |
351 | return retval; | |
352 | } | |
353 | ||
43c8f435 | 354 | static void __exit safe_exit(void) |
1da177e4 | 355 | { |
43c8f435 AC |
356 | usb_deregister(&safe_driver); |
357 | usb_serial_deregister(&safe_device); | |
1da177e4 LT |
358 | } |
359 | ||
43c8f435 AC |
360 | module_init(safe_init); |
361 | module_exit(safe_exit); |