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[PATCH] isdn4linux: Siemens Gigaset drivers: timer usage
[deliverable/linux.git] / drivers / isdn / gigaset / isocdata.c
CommitLineData
76bb4685
HL		 1/*
2 * Common data handling layer for bas_gigaset
3 *
4 * Copyright (c) 2005 by Tilman Schmidt <tilman@imap.cc>,
5 * Hansjoerg Lipp <hjlipp@web.de>.
6 *
7 * =====================================================================
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License as
10 * published by the Free Software Foundation; either version 2 of
11 * the License, or (at your option) any later version.
12 * =====================================================================
76bb4685
HL		 13 */
14
15#include "gigaset.h"
16#include <linux/crc-ccitt.h>
17
18/* access methods for isowbuf_t */
19/* ============================ */
20
21/* initialize buffer structure
22 */
23void gigaset_isowbuf_init(struct isowbuf_t *iwb, unsigned char idle)
24{
25 atomic_set(&iwb->read, 0);
26 atomic_set(&iwb->nextread, 0);
27 atomic_set(&iwb->write, 0);
28 atomic_set(&iwb->writesem, 1);
29 iwb->wbits = 0;
30 iwb->idle = idle;
31 memset(iwb->data + BAS_OUTBUFSIZE, idle, BAS_OUTBUFPAD);
32}
33
34/* compute number of bytes which can be appended to buffer
35 * so that there is still room to append a maximum frame of flags
36 */
37static inline int isowbuf_freebytes(struct isowbuf_t *iwb)
38{
39 int read, write, freebytes;
40
41 read = atomic_read(&iwb->read);
42 write = atomic_read(&iwb->write);
43 if ((freebytes = read - write) > 0) {
44 /* no wraparound: need padding space within regular area */
45 return freebytes - BAS_OUTBUFPAD;
46 } else if (read < BAS_OUTBUFPAD) {
47 /* wraparound: can use space up to end of regular area */
48 return BAS_OUTBUFSIZE - write;
49 } else {
50 /* following the wraparound yields more space */
51 return freebytes + BAS_OUTBUFSIZE - BAS_OUTBUFPAD;
52 }
53}
54
55/* compare two offsets within the buffer
56 * The buffer is seen as circular, with the read position as start
57 * returns -1/0/1 if position a </=/> position b without crossing 'read'
58 */
59static inline int isowbuf_poscmp(struct isowbuf_t *iwb, int a, int b)
60{
61 int read;
62 if (a == b)
63 return 0;
64 read = atomic_read(&iwb->read);
65 if (a < b) {
66 if (a < read && read <= b)
67 return +1;
68 else
69 return -1;
70 } else {
71 if (b < read && read <= a)
72 return -1;
73 else
74 return +1;
75 }
76}
77
78/* start writing
79 * acquire the write semaphore
80 * return true if acquired, false if busy
81 */
82static inline int isowbuf_startwrite(struct isowbuf_t *iwb)
83{
84 if (!atomic_dec_and_test(&iwb->writesem)) {
85 atomic_inc(&iwb->writesem);
86 dbg(DEBUG_ISO,
87 "%s: couldn't acquire iso write semaphore", __func__);
88 return 0;
89 }
90#ifdef CONFIG_GIGASET_DEBUG
91 dbg(DEBUG_ISO,
92 "%s: acquired iso write semaphore, data[write]=%02x, nbits=%d",
93 __func__, iwb->data[atomic_read(&iwb->write)], iwb->wbits);
94#endif
95 return 1;
96}
97
98/* finish writing
99 * release the write semaphore and update the maximum buffer fill level
100 * returns the current write position
101 */
102static inline int isowbuf_donewrite(struct isowbuf_t *iwb)
103{
104 int write = atomic_read(&iwb->write);
105 atomic_inc(&iwb->writesem);
106 return write;
107}
108
109/* append bits to buffer without any checks
110 * - data contains bits to append, starting at LSB
111 * - nbits is number of bits to append (0..24)
112 * must be called with the write semaphore held
113 * If more than nbits bits are set in data, the extraneous bits are set in the
114 * buffer too, but the write position is only advanced by nbits.
115 */
116static inline void isowbuf_putbits(struct isowbuf_t *iwb, u32 data, int nbits)
117{
118 int write = atomic_read(&iwb->write);
119 data <<= iwb->wbits;
120 data |= iwb->data[write];
121 nbits += iwb->wbits;
122 while (nbits >= 8) {
123 iwb->data[write++] = data & 0xff;
124 write %= BAS_OUTBUFSIZE;
125 data >>= 8;
126 nbits -= 8;
127 }
128 iwb->wbits = nbits;
129 iwb->data[write] = data & 0xff;
130 atomic_set(&iwb->write, write);
131}
132
133/* put final flag on HDLC bitstream
134 * also sets the idle fill byte to the correspondingly shifted flag pattern
135 * must be called with the write semaphore held
136 */
137static inline void isowbuf_putflag(struct isowbuf_t *iwb)
138{
139 int write;
140
141 /* add two flags, thus reliably covering one byte */
142 isowbuf_putbits(iwb, 0x7e7e, 8);
143 /* recover the idle flag byte */
144 write = atomic_read(&iwb->write);
145 iwb->idle = iwb->data[write];
146 dbg(DEBUG_ISO, "idle fill byte %02x", iwb->idle);
147 /* mask extraneous bits in buffer */
148 iwb->data[write] &= (1 << iwb->wbits) - 1;
149}
150
151/* retrieve a block of bytes for sending
152 * The requested number of bytes is provided as a contiguous block.
153 * If necessary, the frame is filled to the requested number of bytes
154 * with the idle value.
155 * returns offset to frame, < 0 on busy or error
156 */
157int gigaset_isowbuf_getbytes(struct isowbuf_t *iwb, int size)
158{
159 int read, write, limit, src, dst;
160 unsigned char pbyte;
161
162 read = atomic_read(&iwb->nextread);
163 write = atomic_read(&iwb->write);
164 if (likely(read == write)) {
165 //dbg(DEBUG_STREAM, "%s: send buffer empty", __func__);
166 /* return idle frame */
167 return read < BAS_OUTBUFPAD ?
168 BAS_OUTBUFSIZE : read - BAS_OUTBUFPAD;
169 }
170
171 limit = read + size;
172 dbg(DEBUG_STREAM,
173 "%s: read=%d write=%d limit=%d", __func__, read, write, limit);
174#ifdef CONFIG_GIGASET_DEBUG
175 if (unlikely(size < 0 || size > BAS_OUTBUFPAD)) {
176 err("invalid size %d", size);
177 return -EINVAL;
178 }
179 src = atomic_read(&iwb->read);
180 if (unlikely(limit > BAS_OUTBUFSIZE + BAS_OUTBUFPAD ||
181 (read < src && limit >= src))) {
182 err("isoc write buffer frame reservation violated");
183 return -EFAULT;
184 }
185#endif
186
187 if (read < write) {
188 /* no wraparound in valid data */
189 if (limit >= write) {
190 /* append idle frame */
191 if (!isowbuf_startwrite(iwb))
192 return -EBUSY;
193 /* write position could have changed */
194 if (limit >= (write = atomic_read(&iwb->write))) {
917f5085
TS		 195 pbyte = iwb->data[write]; /* save
196 partial byte */
76bb4685
HL		 197 limit = write + BAS_OUTBUFPAD;
198 dbg(DEBUG_STREAM,
199 "%s: filling %d->%d with %02x",
200 __func__, write, limit, iwb->idle);
201 if (write + BAS_OUTBUFPAD < BAS_OUTBUFSIZE)
202 memset(iwb->data + write, iwb->idle,
203 BAS_OUTBUFPAD);
204 else {
205 /* wraparound, fill entire pad area */
206 memset(iwb->data + write, iwb->idle,
207 BAS_OUTBUFSIZE + BAS_OUTBUFPAD
208 - write);
209 limit = 0;
210 }
211 dbg(DEBUG_STREAM, "%s: restoring %02x at %d",
212 __func__, pbyte, limit);
917f5085
TS		 213 iwb->data[limit] = pbyte; /* restore
214 partial byte */
76bb4685
HL		 215 atomic_set(&iwb->write, limit);
216 }
217 isowbuf_donewrite(iwb);
218 }
219 } else {
220 /* valid data wraparound */
221 if (limit >= BAS_OUTBUFSIZE) {
222 /* copy wrapped part into pad area */
223 src = 0;
224 dst = BAS_OUTBUFSIZE;
225 while (dst < limit && src < write)
226 iwb->data[dst++] = iwb->data[src++];
227 if (dst <= limit) {
228 /* fill pad area with idle byte */
229 memset(iwb->data + dst, iwb->idle,
230 BAS_OUTBUFSIZE + BAS_OUTBUFPAD - dst);
231 }
232 limit = src;
233 }
234 }
235 atomic_set(&iwb->nextread, limit);
236 return read;
237}
238
239/* dump_bytes
240 * write hex bytes to syslog for debugging
241 */
242static inline void dump_bytes(enum debuglevel level, const char *tag,
243 unsigned char *bytes, int count)
244{
245#ifdef CONFIG_GIGASET_DEBUG
246 unsigned char c;
247 static char dbgline[3 * 32 + 1];
248 static const char hexdigit[] = "0123456789abcdef";
249 int i = 0;
250 IFNULLRET(tag);
251 IFNULLRET(bytes);
252 while (count-- > 0) {
253 if (i > sizeof(dbgline) - 4) {
254 dbgline[i] = '\0';
255 dbg(level, "%s:%s", tag, dbgline);
256 i = 0;
257 }
258 c = *bytes++;
259 dbgline[i] = (i && !(i % 12)) ? '-' : ' ';
260 i++;
261 dbgline[i++] = hexdigit[(c >> 4) & 0x0f];
262 dbgline[i++] = hexdigit[c & 0x0f];
263 }
264 dbgline[i] = '\0';
265 dbg(level, "%s:%s", tag, dbgline);
266#endif
267}
268
269/*============================================================================*/
270
271/* bytewise HDLC bitstuffing via table lookup
272 * lookup table: 5 subtables for 0..4 preceding consecutive '1' bits
273 * index: 256*(number of preceding '1' bits) + (next byte to stuff)
274 * value: bit 9.. 0 = result bits
275 * bit 12..10 = number of trailing '1' bits in result
276 * bit 14..13 = number of bits added by stuffing
277 */
278static u16 stufftab[5 * 256] = {
279// previous 1s = 0:
280 0x0000, 0x0001, 0x0002, 0x0003, 0x0004, 0x0005, 0x0006, 0x0007, 0x0008, 0x0009, 0x000a, 0x000b, 0x000c, 0x000d, 0x000e, 0x000f,
281 0x0010, 0x0011, 0x0012, 0x0013, 0x0014, 0x0015, 0x0016, 0x0017, 0x0018, 0x0019, 0x001a, 0x001b, 0x001c, 0x001d, 0x001e, 0x201f,
282 0x0020, 0x0021, 0x0022, 0x0023, 0x0024, 0x0025, 0x0026, 0x0027, 0x0028, 0x0029, 0x002a, 0x002b, 0x002c, 0x002d, 0x002e, 0x002f,
283 0x0030, 0x0031, 0x0032, 0x0033, 0x0034, 0x0035, 0x0036, 0x0037, 0x0038, 0x0039, 0x003a, 0x003b, 0x003c, 0x003d, 0x203e, 0x205f,
284 0x0040, 0x0041, 0x0042, 0x0043, 0x0044, 0x0045, 0x0046, 0x0047, 0x0048, 0x0049, 0x004a, 0x004b, 0x004c, 0x004d, 0x004e, 0x004f,
285 0x0050, 0x0051, 0x0052, 0x0053, 0x0054, 0x0055, 0x0056, 0x0057, 0x0058, 0x0059, 0x005a, 0x005b, 0x005c, 0x005d, 0x005e, 0x209f,
286 0x0060, 0x0061, 0x0062, 0x0063, 0x0064, 0x0065, 0x0066, 0x0067, 0x0068, 0x0069, 0x006a, 0x006b, 0x006c, 0x006d, 0x006e, 0x006f,
287 0x0070, 0x0071, 0x0072, 0x0073, 0x0074, 0x0075, 0x0076, 0x0077, 0x0078, 0x0079, 0x007a, 0x007b, 0x207c, 0x207d, 0x20be, 0x20df,
288 0x0480, 0x0481, 0x0482, 0x0483, 0x0484, 0x0485, 0x0486, 0x0487, 0x0488, 0x0489, 0x048a, 0x048b, 0x048c, 0x048d, 0x048e, 0x048f,
289 0x0490, 0x0491, 0x0492, 0x0493, 0x0494, 0x0495, 0x0496, 0x0497, 0x0498, 0x0499, 0x049a, 0x049b, 0x049c, 0x049d, 0x049e, 0x251f,
290 0x04a0, 0x04a1, 0x04a2, 0x04a3, 0x04a4, 0x04a5, 0x04a6, 0x04a7, 0x04a8, 0x04a9, 0x04aa, 0x04ab, 0x04ac, 0x04ad, 0x04ae, 0x04af,
291 0x04b0, 0x04b1, 0x04b2, 0x04b3, 0x04b4, 0x04b5, 0x04b6, 0x04b7, 0x04b8, 0x04b9, 0x04ba, 0x04bb, 0x04bc, 0x04bd, 0x253e, 0x255f,
292 0x08c0, 0x08c1, 0x08c2, 0x08c3, 0x08c4, 0x08c5, 0x08c6, 0x08c7, 0x08c8, 0x08c9, 0x08ca, 0x08cb, 0x08cc, 0x08cd, 0x08ce, 0x08cf,
293 0x08d0, 0x08d1, 0x08d2, 0x08d3, 0x08d4, 0x08d5, 0x08d6, 0x08d7, 0x08d8, 0x08d9, 0x08da, 0x08db, 0x08dc, 0x08dd, 0x08de, 0x299f,
294 0x0ce0, 0x0ce1, 0x0ce2, 0x0ce3, 0x0ce4, 0x0ce5, 0x0ce6, 0x0ce7, 0x0ce8, 0x0ce9, 0x0cea, 0x0ceb, 0x0cec, 0x0ced, 0x0cee, 0x0cef,
295 0x10f0, 0x10f1, 0x10f2, 0x10f3, 0x10f4, 0x10f5, 0x10f6, 0x10f7, 0x20f8, 0x20f9, 0x20fa, 0x20fb, 0x257c, 0x257d, 0x29be, 0x2ddf,
296
297// previous 1s = 1:
298 0x0000, 0x0001, 0x0002, 0x0003, 0x0004, 0x0005, 0x0006, 0x0007, 0x0008, 0x0009, 0x000a, 0x000b, 0x000c, 0x000d, 0x000e, 0x200f,
299 0x0010, 0x0011, 0x0012, 0x0013, 0x0014, 0x0015, 0x0016, 0x0017, 0x0018, 0x0019, 0x001a, 0x001b, 0x001c, 0x001d, 0x001e, 0x202f,
300 0x0020, 0x0021, 0x0022, 0x0023, 0x0024, 0x0025, 0x0026, 0x0027, 0x0028, 0x0029, 0x002a, 0x002b, 0x002c, 0x002d, 0x002e, 0x204f,
301 0x0030, 0x0031, 0x0032, 0x0033, 0x0034, 0x0035, 0x0036, 0x0037, 0x0038, 0x0039, 0x003a, 0x003b, 0x003c, 0x003d, 0x203e, 0x206f,
302 0x0040, 0x0041, 0x0042, 0x0043, 0x0044, 0x0045, 0x0046, 0x0047, 0x0048, 0x0049, 0x004a, 0x004b, 0x004c, 0x004d, 0x004e, 0x208f,
303 0x0050, 0x0051, 0x0052, 0x0053, 0x0054, 0x0055, 0x0056, 0x0057, 0x0058, 0x0059, 0x005a, 0x005b, 0x005c, 0x005d, 0x005e, 0x20af,
304 0x0060, 0x0061, 0x0062, 0x0063, 0x0064, 0x0065, 0x0066, 0x0067, 0x0068, 0x0069, 0x006a, 0x006b, 0x006c, 0x006d, 0x006e, 0x20cf,
305 0x0070, 0x0071, 0x0072, 0x0073, 0x0074, 0x0075, 0x0076, 0x0077, 0x0078, 0x0079, 0x007a, 0x007b, 0x207c, 0x207d, 0x20be, 0x20ef,
306 0x0480, 0x0481, 0x0482, 0x0483, 0x0484, 0x0485, 0x0486, 0x0487, 0x0488, 0x0489, 0x048a, 0x048b, 0x048c, 0x048d, 0x048e, 0x250f,
307 0x0490, 0x0491, 0x0492, 0x0493, 0x0494, 0x0495, 0x0496, 0x0497, 0x0498, 0x0499, 0x049a, 0x049b, 0x049c, 0x049d, 0x049e, 0x252f,
308 0x04a0, 0x04a1, 0x04a2, 0x04a3, 0x04a4, 0x04a5, 0x04a6, 0x04a7, 0x04a8, 0x04a9, 0x04aa, 0x04ab, 0x04ac, 0x04ad, 0x04ae, 0x254f,
309 0x04b0, 0x04b1, 0x04b2, 0x04b3, 0x04b4, 0x04b5, 0x04b6, 0x04b7, 0x04b8, 0x04b9, 0x04ba, 0x04bb, 0x04bc, 0x04bd, 0x253e, 0x256f,
310 0x08c0, 0x08c1, 0x08c2, 0x08c3, 0x08c4, 0x08c5, 0x08c6, 0x08c7, 0x08c8, 0x08c9, 0x08ca, 0x08cb, 0x08cc, 0x08cd, 0x08ce, 0x298f,
311 0x08d0, 0x08d1, 0x08d2, 0x08d3, 0x08d4, 0x08d5, 0x08d6, 0x08d7, 0x08d8, 0x08d9, 0x08da, 0x08db, 0x08dc, 0x08dd, 0x08de, 0x29af,
312 0x0ce0, 0x0ce1, 0x0ce2, 0x0ce3, 0x0ce4, 0x0ce5, 0x0ce6, 0x0ce7, 0x0ce8, 0x0ce9, 0x0cea, 0x0ceb, 0x0cec, 0x0ced, 0x0cee, 0x2dcf,
313 0x10f0, 0x10f1, 0x10f2, 0x10f3, 0x10f4, 0x10f5, 0x10f6, 0x10f7, 0x20f8, 0x20f9, 0x20fa, 0x20fb, 0x257c, 0x257d, 0x29be, 0x31ef,
314
315// previous 1s = 2:
316 0x0000, 0x0001, 0x0002, 0x0003, 0x0004, 0x0005, 0x0006, 0x2007, 0x0008, 0x0009, 0x000a, 0x000b, 0x000c, 0x000d, 0x000e, 0x2017,
317 0x0010, 0x0011, 0x0012, 0x0013, 0x0014, 0x0015, 0x0016, 0x2027, 0x0018, 0x0019, 0x001a, 0x001b, 0x001c, 0x001d, 0x001e, 0x2037,
318 0x0020, 0x0021, 0x0022, 0x0023, 0x0024, 0x0025, 0x0026, 0x2047, 0x0028, 0x0029, 0x002a, 0x002b, 0x002c, 0x002d, 0x002e, 0x2057,
319 0x0030, 0x0031, 0x0032, 0x0033, 0x0034, 0x0035, 0x0036, 0x2067, 0x0038, 0x0039, 0x003a, 0x003b, 0x003c, 0x003d, 0x203e, 0x2077,
320 0x0040, 0x0041, 0x0042, 0x0043, 0x0044, 0x0045, 0x0046, 0x2087, 0x0048, 0x0049, 0x004a, 0x004b, 0x004c, 0x004d, 0x004e, 0x2097,
321 0x0050, 0x0051, 0x0052, 0x0053, 0x0054, 0x0055, 0x0056, 0x20a7, 0x0058, 0x0059, 0x005a, 0x005b, 0x005c, 0x005d, 0x005e, 0x20b7,
322 0x0060, 0x0061, 0x0062, 0x0063, 0x0064, 0x0065, 0x0066, 0x20c7, 0x0068, 0x0069, 0x006a, 0x006b, 0x006c, 0x006d, 0x006e, 0x20d7,
323 0x0070, 0x0071, 0x0072, 0x0073, 0x0074, 0x0075, 0x0076, 0x20e7, 0x0078, 0x0079, 0x007a, 0x007b, 0x207c, 0x207d, 0x20be, 0x20f7,
324 0x0480, 0x0481, 0x0482, 0x0483, 0x0484, 0x0485, 0x0486, 0x2507, 0x0488, 0x0489, 0x048a, 0x048b, 0x048c, 0x048d, 0x048e, 0x2517,
325 0x0490, 0x0491, 0x0492, 0x0493, 0x0494, 0x0495, 0x0496, 0x2527, 0x0498, 0x0499, 0x049a, 0x049b, 0x049c, 0x049d, 0x049e, 0x2537,
326 0x04a0, 0x04a1, 0x04a2, 0x04a3, 0x04a4, 0x04a5, 0x04a6, 0x2547, 0x04a8, 0x04a9, 0x04aa, 0x04ab, 0x04ac, 0x04ad, 0x04ae, 0x2557,
327 0x04b0, 0x04b1, 0x04b2, 0x04b3, 0x04b4, 0x04b5, 0x04b6, 0x2567, 0x04b8, 0x04b9, 0x04ba, 0x04bb, 0x04bc, 0x04bd, 0x253e, 0x2577,
328 0x08c0, 0x08c1, 0x08c2, 0x08c3, 0x08c4, 0x08c5, 0x08c6, 0x2987, 0x08c8, 0x08c9, 0x08ca, 0x08cb, 0x08cc, 0x08cd, 0x08ce, 0x2997,
329 0x08d0, 0x08d1, 0x08d2, 0x08d3, 0x08d4, 0x08d5, 0x08d6, 0x29a7, 0x08d8, 0x08d9, 0x08da, 0x08db, 0x08dc, 0x08dd, 0x08de, 0x29b7,
330 0x0ce0, 0x0ce1, 0x0ce2, 0x0ce3, 0x0ce4, 0x0ce5, 0x0ce6, 0x2dc7, 0x0ce8, 0x0ce9, 0x0cea, 0x0ceb, 0x0cec, 0x0ced, 0x0cee, 0x2dd7,
331 0x10f0, 0x10f1, 0x10f2, 0x10f3, 0x10f4, 0x10f5, 0x10f6, 0x31e7, 0x20f8, 0x20f9, 0x20fa, 0x20fb, 0x257c, 0x257d, 0x29be, 0x41f7,
332
333// previous 1s = 3:
334 0x0000, 0x0001, 0x0002, 0x2003, 0x0004, 0x0005, 0x0006, 0x200b, 0x0008, 0x0009, 0x000a, 0x2013, 0x000c, 0x000d, 0x000e, 0x201b,
335 0x0010, 0x0011, 0x0012, 0x2023, 0x0014, 0x0015, 0x0016, 0x202b, 0x0018, 0x0019, 0x001a, 0x2033, 0x001c, 0x001d, 0x001e, 0x203b,
336 0x0020, 0x0021, 0x0022, 0x2043, 0x0024, 0x0025, 0x0026, 0x204b, 0x0028, 0x0029, 0x002a, 0x2053, 0x002c, 0x002d, 0x002e, 0x205b,
337 0x0030, 0x0031, 0x0032, 0x2063, 0x0034, 0x0035, 0x0036, 0x206b, 0x0038, 0x0039, 0x003a, 0x2073, 0x003c, 0x003d, 0x203e, 0x207b,
338 0x0040, 0x0041, 0x0042, 0x2083, 0x0044, 0x0045, 0x0046, 0x208b, 0x0048, 0x0049, 0x004a, 0x2093, 0x004c, 0x004d, 0x004e, 0x209b,
339 0x0050, 0x0051, 0x0052, 0x20a3, 0x0054, 0x0055, 0x0056, 0x20ab, 0x0058, 0x0059, 0x005a, 0x20b3, 0x005c, 0x005d, 0x005e, 0x20bb,
340 0x0060, 0x0061, 0x0062, 0x20c3, 0x0064, 0x0065, 0x0066, 0x20cb, 0x0068, 0x0069, 0x006a, 0x20d3, 0x006c, 0x006d, 0x006e, 0x20db,
341 0x0070, 0x0071, 0x0072, 0x20e3, 0x0074, 0x0075, 0x0076, 0x20eb, 0x0078, 0x0079, 0x007a, 0x20f3, 0x207c, 0x207d, 0x20be, 0x40fb,
342 0x0480, 0x0481, 0x0482, 0x2503, 0x0484, 0x0485, 0x0486, 0x250b, 0x0488, 0x0489, 0x048a, 0x2513, 0x048c, 0x048d, 0x048e, 0x251b,
343 0x0490, 0x0491, 0x0492, 0x2523, 0x0494, 0x0495, 0x0496, 0x252b, 0x0498, 0x0499, 0x049a, 0x2533, 0x049c, 0x049d, 0x049e, 0x253b,
344 0x04a0, 0x04a1, 0x04a2, 0x2543, 0x04a4, 0x04a5, 0x04a6, 0x254b, 0x04a8, 0x04a9, 0x04aa, 0x2553, 0x04ac, 0x04ad, 0x04ae, 0x255b,
345 0x04b0, 0x04b1, 0x04b2, 0x2563, 0x04b4, 0x04b5, 0x04b6, 0x256b, 0x04b8, 0x04b9, 0x04ba, 0x2573, 0x04bc, 0x04bd, 0x253e, 0x257b,
346 0x08c0, 0x08c1, 0x08c2, 0x2983, 0x08c4, 0x08c5, 0x08c6, 0x298b, 0x08c8, 0x08c9, 0x08ca, 0x2993, 0x08cc, 0x08cd, 0x08ce, 0x299b,
347 0x08d0, 0x08d1, 0x08d2, 0x29a3, 0x08d4, 0x08d5, 0x08d6, 0x29ab, 0x08d8, 0x08d9, 0x08da, 0x29b3, 0x08dc, 0x08dd, 0x08de, 0x29bb,
348 0x0ce0, 0x0ce1, 0x0ce2, 0x2dc3, 0x0ce4, 0x0ce5, 0x0ce6, 0x2dcb, 0x0ce8, 0x0ce9, 0x0cea, 0x2dd3, 0x0cec, 0x0ced, 0x0cee, 0x2ddb,
349 0x10f0, 0x10f1, 0x10f2, 0x31e3, 0x10f4, 0x10f5, 0x10f6, 0x31eb, 0x20f8, 0x20f9, 0x20fa, 0x41f3, 0x257c, 0x257d, 0x29be, 0x46fb,
350
351// previous 1s = 4:
352 0x0000, 0x2001, 0x0002, 0x2005, 0x0004, 0x2009, 0x0006, 0x200d, 0x0008, 0x2011, 0x000a, 0x2015, 0x000c, 0x2019, 0x000e, 0x201d,
353 0x0010, 0x2021, 0x0012, 0x2025, 0x0014, 0x2029, 0x0016, 0x202d, 0x0018, 0x2031, 0x001a, 0x2035, 0x001c, 0x2039, 0x001e, 0x203d,
354 0x0020, 0x2041, 0x0022, 0x2045, 0x0024, 0x2049, 0x0026, 0x204d, 0x0028, 0x2051, 0x002a, 0x2055, 0x002c, 0x2059, 0x002e, 0x205d,
355 0x0030, 0x2061, 0x0032, 0x2065, 0x0034, 0x2069, 0x0036, 0x206d, 0x0038, 0x2071, 0x003a, 0x2075, 0x003c, 0x2079, 0x203e, 0x407d,
356 0x0040, 0x2081, 0x0042, 0x2085, 0x0044, 0x2089, 0x0046, 0x208d, 0x0048, 0x2091, 0x004a, 0x2095, 0x004c, 0x2099, 0x004e, 0x209d,
357 0x0050, 0x20a1, 0x0052, 0x20a5, 0x0054, 0x20a9, 0x0056, 0x20ad, 0x0058, 0x20b1, 0x005a, 0x20b5, 0x005c, 0x20b9, 0x005e, 0x20bd,
358 0x0060, 0x20c1, 0x0062, 0x20c5, 0x0064, 0x20c9, 0x0066, 0x20cd, 0x0068, 0x20d1, 0x006a, 0x20d5, 0x006c, 0x20d9, 0x006e, 0x20dd,
359 0x0070, 0x20e1, 0x0072, 0x20e5, 0x0074, 0x20e9, 0x0076, 0x20ed, 0x0078, 0x20f1, 0x007a, 0x20f5, 0x207c, 0x40f9, 0x20be, 0x417d,
360 0x0480, 0x2501, 0x0482, 0x2505, 0x0484, 0x2509, 0x0486, 0x250d, 0x0488, 0x2511, 0x048a, 0x2515, 0x048c, 0x2519, 0x048e, 0x251d,
361 0x0490, 0x2521, 0x0492, 0x2525, 0x0494, 0x2529, 0x0496, 0x252d, 0x0498, 0x2531, 0x049a, 0x2535, 0x049c, 0x2539, 0x049e, 0x253d,
362 0x04a0, 0x2541, 0x04a2, 0x2545, 0x04a4, 0x2549, 0x04a6, 0x254d, 0x04a8, 0x2551, 0x04aa, 0x2555, 0x04ac, 0x2559, 0x04ae, 0x255d,
363 0x04b0, 0x2561, 0x04b2, 0x2565, 0x04b4, 0x2569, 0x04b6, 0x256d, 0x04b8, 0x2571, 0x04ba, 0x2575, 0x04bc, 0x2579, 0x253e, 0x467d,
364 0x08c0, 0x2981, 0x08c2, 0x2985, 0x08c4, 0x2989, 0x08c6, 0x298d, 0x08c8, 0x2991, 0x08ca, 0x2995, 0x08cc, 0x2999, 0x08ce, 0x299d,
365 0x08d0, 0x29a1, 0x08d2, 0x29a5, 0x08d4, 0x29a9, 0x08d6, 0x29ad, 0x08d8, 0x29b1, 0x08da, 0x29b5, 0x08dc, 0x29b9, 0x08de, 0x29bd,
366 0x0ce0, 0x2dc1, 0x0ce2, 0x2dc5, 0x0ce4, 0x2dc9, 0x0ce6, 0x2dcd, 0x0ce8, 0x2dd1, 0x0cea, 0x2dd5, 0x0cec, 0x2dd9, 0x0cee, 0x2ddd,
367 0x10f0, 0x31e1, 0x10f2, 0x31e5, 0x10f4, 0x31e9, 0x10f6, 0x31ed, 0x20f8, 0x41f1, 0x20fa, 0x41f5, 0x257c, 0x46f9, 0x29be, 0x4b7d
368};
369
370/* hdlc_bitstuff_byte
371 * perform HDLC bitstuffing for one input byte (8 bits, LSB first)
372 * parameters:
373 * cin input byte
374 * ones number of trailing '1' bits in result before this step
375 * iwb pointer to output buffer structure (write semaphore must be held)
376 * return value:
377 * number of trailing '1' bits in result after this step
378 */
379
380static inline int hdlc_bitstuff_byte(struct isowbuf_t *iwb, unsigned char cin,
381 int ones)
382{
383 u16 stuff;
384 int shiftinc, newones;
385
386 /* get stuffing information for input byte
387 * value: bit 9.. 0 = result bits
388 * bit 12..10 = number of trailing '1' bits in result
389 * bit 14..13 = number of bits added by stuffing
390 */
391 stuff = stufftab[256 * ones + cin];
392 shiftinc = (stuff >> 13) & 3;
393 newones = (stuff >> 10) & 7;
394 stuff &= 0x3ff;
395
396 /* append stuffed byte to output stream */
397 isowbuf_putbits(iwb, stuff, 8 + shiftinc);
398 return newones;
399}
400
401/* hdlc_buildframe
402 * Perform HDLC framing with bitstuffing on a byte buffer
403 * The input buffer is regarded as a sequence of bits, starting with the least
404 * significant bit of the first byte and ending with the most significant bit
405 * of the last byte. A 16 bit FCS is appended as defined by RFC 1662.
406 * Whenever five consecutive '1' bits appear in the resulting bit sequence, a
407 * '0' bit is inserted after them.
408 * The resulting bit string and a closing flag pattern (PPP_FLAG, '01111110')
409 * are appended to the output buffer starting at the given bit position, which
410 * is assumed to already contain a leading flag.
411 * The output buffer must have sufficient length; count + count/5 + 6 bytes
412 * starting at *out are safe and are verified to be present.
413 * parameters:
414 * in input buffer
415 * count number of bytes in input buffer
416 * iwb pointer to output buffer structure (write semaphore must be held)
417 * return value:
418 * position of end of packet in output buffer on success,
419 * -EAGAIN if write semaphore busy or buffer full
420 */
421
422static inline int hdlc_buildframe(struct isowbuf_t *iwb,
423 unsigned char *in, int count)
424{
425 int ones;
426 u16 fcs;
427 int end;
428 unsigned char c;
429
430 if (isowbuf_freebytes(iwb) < count + count / 5 + 6 ||
431 !isowbuf_startwrite(iwb)) {
432 dbg(DEBUG_ISO, "%s: %d bytes free -> -EAGAIN",
433 __func__, isowbuf_freebytes(iwb));
434 return -EAGAIN;
435 }
436
437 dump_bytes(DEBUG_STREAM, "snd data", in, count);
438
439 /* bitstuff and checksum input data */
440 fcs = PPP_INITFCS;
441 ones = 0;
442 while (count-- > 0) {
443 c = *in++;
444 ones = hdlc_bitstuff_byte(iwb, c, ones);
445 fcs = crc_ccitt_byte(fcs, c);
446 }
447
448 /* bitstuff and append FCS (complemented, least significant byte first) */
449 fcs ^= 0xffff;
450 ones = hdlc_bitstuff_byte(iwb, fcs & 0x00ff, ones);
451 ones = hdlc_bitstuff_byte(iwb, (fcs >> 8) & 0x00ff, ones);
452
453 /* put closing flag and repeat byte for flag idle */
454 isowbuf_putflag(iwb);
455 end = isowbuf_donewrite(iwb);
456 dump_bytes(DEBUG_STREAM_DUMP, "isowbuf", iwb->data, end + 1);
457 return end;
458}
459
460/* trans_buildframe
461 * Append a block of 'transparent' data to the output buffer,
462 * inverting the bytes.
463 * The output buffer must have sufficient length; count bytes
464 * starting at *out are safe and are verified to be present.
465 * parameters:
466 * in input buffer
467 * count number of bytes in input buffer
468 * iwb pointer to output buffer structure (write semaphore must be held)
469 * return value:
470 * position of end of packet in output buffer on success,
471 * -EAGAIN if write semaphore busy or buffer full
472 */
473
474static inline int trans_buildframe(struct isowbuf_t *iwb,
475 unsigned char *in, int count)
476{
477 int write;
478 unsigned char c;
479
480 if (unlikely(count <= 0))
481 return atomic_read(&iwb->write); /* better ideas? */
482
483 if (isowbuf_freebytes(iwb) < count ||
484 !isowbuf_startwrite(iwb)) {
485 dbg(DEBUG_ISO, "can't put %d bytes", count);
486 return -EAGAIN;
487 }
488
489 dbg(DEBUG_STREAM, "put %d bytes", count);
490 write = atomic_read(&iwb->write);
491 do {
492 c = gigaset_invtab[*in++];
493 iwb->data[write++] = c;
494 write %= BAS_OUTBUFSIZE;
495 } while (--count > 0);
496 atomic_set(&iwb->write, write);
497 iwb->idle = c;
498
499 return isowbuf_donewrite(iwb);
500}
501
502int gigaset_isoc_buildframe(struct bc_state *bcs, unsigned char *in, int len)
503{
504 int result;
505
506 switch (bcs->proto2) {
507 case ISDN_PROTO_L2_HDLC:
508 result = hdlc_buildframe(bcs->hw.bas->isooutbuf, in, len);
917f5085
TS		 509 dbg(DEBUG_ISO, "%s: %d bytes HDLC -> %d",
510 __func__, len, result);
76bb4685
HL		 511 break;
512 default: /* assume transparent */
513 result = trans_buildframe(bcs->hw.bas->isooutbuf, in, len);
917f5085
TS		 514 dbg(DEBUG_ISO, "%s: %d bytes trans -> %d",
515 __func__, len, result);
76bb4685
HL		 516 }
517 return result;
518}
519
520/* hdlc_putbyte
521 * append byte c to current skb of B channel structure *bcs, updating fcs
522 */
523static inline void hdlc_putbyte(unsigned char c, struct bc_state *bcs)
524{
525 bcs->fcs = crc_ccitt_byte(bcs->fcs, c);
526 if (unlikely(bcs->skb == NULL)) {
527 /* skipping */
528 return;
529 }
530 if (unlikely(bcs->skb->len == SBUFSIZE)) {
531 warn("received oversized packet discarded");
532 bcs->hw.bas->giants++;
533 dev_kfree_skb_any(bcs->skb);
534 bcs->skb = NULL;
535 return;
536 }
537 *gigaset_skb_put_quick(bcs->skb, 1) = c;
538}
539
540/* hdlc_flush
541 * drop partial HDLC data packet
542 */
543static inline void hdlc_flush(struct bc_state *bcs)
544{
545 /* clear skb or allocate new if not skipping */
546 if (likely(bcs->skb != NULL))
547 skb_trim(bcs->skb, 0);
548 else if (!bcs->ignore) {
549 if ((bcs->skb = dev_alloc_skb(SBUFSIZE + HW_HDR_LEN)) != NULL)
550 skb_reserve(bcs->skb, HW_HDR_LEN);
551 else
552 err("could not allocate skb");
553 }
554
555 /* reset packet state */
556 bcs->fcs = PPP_INITFCS;
557}
558
559/* hdlc_done
560 * process completed HDLC data packet
561 */
562static inline void hdlc_done(struct bc_state *bcs)
563{
564 struct sk_buff *procskb;
565
566 if (unlikely(bcs->ignore)) {
567 bcs->ignore--;
568 hdlc_flush(bcs);
569 return;
570 }
571
572 if ((procskb = bcs->skb) == NULL) {
573 /* previous error */
574 dbg(DEBUG_ISO, "%s: skb=NULL", __func__);
575 gigaset_rcv_error(NULL, bcs->cs, bcs);
576 } else if (procskb->len < 2) {
577 notice("received short frame (%d octets)", procskb->len);
578 bcs->hw.bas->runts++;
579 gigaset_rcv_error(procskb, bcs->cs, bcs);
580 } else if (bcs->fcs != PPP_GOODFCS) {
581 notice("frame check error (0x%04x)", bcs->fcs);
582 bcs->hw.bas->fcserrs++;
583 gigaset_rcv_error(procskb, bcs->cs, bcs);
584 } else {
585 procskb->len -= 2; /* subtract FCS */
586 procskb->tail -= 2;
587 dbg(DEBUG_ISO,
588 "%s: good frame (%d octets)", __func__, procskb->len);
589 dump_bytes(DEBUG_STREAM,
590 "rcv data", procskb->data, procskb->len);
591 bcs->hw.bas->goodbytes += procskb->len;
592 gigaset_rcv_skb(procskb, bcs->cs, bcs);
593 }
594
595 if ((bcs->skb = dev_alloc_skb(SBUFSIZE + HW_HDR_LEN)) != NULL)
596 skb_reserve(bcs->skb, HW_HDR_LEN);
597 else
598 err("could not allocate skb");
599 bcs->fcs = PPP_INITFCS;
600}
601
602/* hdlc_frag
603 * drop HDLC data packet with non-integral last byte
604 */
605static inline void hdlc_frag(struct bc_state *bcs, unsigned inbits)
606{
607 if (unlikely(bcs->ignore)) {
608 bcs->ignore--;
609 hdlc_flush(bcs);
610 return;
611 }
612
613 notice("received partial byte (%d bits)", inbits);
614 bcs->hw.bas->alignerrs++;
615 gigaset_rcv_error(bcs->skb, bcs->cs, bcs);
616
617 if ((bcs->skb = dev_alloc_skb(SBUFSIZE + HW_HDR_LEN)) != NULL)
618 skb_reserve(bcs->skb, HW_HDR_LEN);
619 else
620 err("could not allocate skb");
621 bcs->fcs = PPP_INITFCS;
622}
623
624/* bit counts lookup table for HDLC bit unstuffing
625 * index: input byte
626 * value: bit 0..3 = number of consecutive '1' bits starting from LSB
627 * bit 4..6 = number of consecutive '1' bits starting from MSB
628 * (replacing 8 by 7 to make it fit; the algorithm won't care)
629 * bit 7 set if there are 5 or more "interior" consecutive '1' bits
630 */
631static unsigned char bitcounts[256] = {
632 0x00, 0x01, 0x00, 0x02, 0x00, 0x01, 0x00, 0x03, 0x00, 0x01, 0x00, 0x02, 0x00, 0x01, 0x00, 0x04,
633 0x00, 0x01, 0x00, 0x02, 0x00, 0x01, 0x00, 0x03, 0x00, 0x01, 0x00, 0x02, 0x00, 0x01, 0x00, 0x05,
634 0x00, 0x01, 0x00, 0x02, 0x00, 0x01, 0x00, 0x03, 0x00, 0x01, 0x00, 0x02, 0x00, 0x01, 0x00, 0x04,
635 0x00, 0x01, 0x00, 0x02, 0x00, 0x01, 0x00, 0x03, 0x00, 0x01, 0x00, 0x02, 0x00, 0x01, 0x80, 0x06,
636 0x00, 0x01, 0x00, 0x02, 0x00, 0x01, 0x00, 0x03, 0x00, 0x01, 0x00, 0x02, 0x00, 0x01, 0x00, 0x04,
637 0x00, 0x01, 0x00, 0x02, 0x00, 0x01, 0x00, 0x03, 0x00, 0x01, 0x00, 0x02, 0x00, 0x01, 0x00, 0x05,
638 0x00, 0x01, 0x00, 0x02, 0x00, 0x01, 0x00, 0x03, 0x00, 0x01, 0x00, 0x02, 0x00, 0x01, 0x00, 0x04,
639 0x00, 0x01, 0x00, 0x02, 0x00, 0x01, 0x00, 0x03, 0x00, 0x01, 0x00, 0x02, 0x80, 0x81, 0x80, 0x07,
640 0x10, 0x11, 0x10, 0x12, 0x10, 0x11, 0x10, 0x13, 0x10, 0x11, 0x10, 0x12, 0x10, 0x11, 0x10, 0x14,
641 0x10, 0x11, 0x10, 0x12, 0x10, 0x11, 0x10, 0x13, 0x10, 0x11, 0x10, 0x12, 0x10, 0x11, 0x10, 0x15,
642 0x10, 0x11, 0x10, 0x12, 0x10, 0x11, 0x10, 0x13, 0x10, 0x11, 0x10, 0x12, 0x10, 0x11, 0x10, 0x14,
643 0x10, 0x11, 0x10, 0x12, 0x10, 0x11, 0x10, 0x13, 0x10, 0x11, 0x10, 0x12, 0x10, 0x11, 0x90, 0x16,
644 0x20, 0x21, 0x20, 0x22, 0x20, 0x21, 0x20, 0x23, 0x20, 0x21, 0x20, 0x22, 0x20, 0x21, 0x20, 0x24,
645 0x20, 0x21, 0x20, 0x22, 0x20, 0x21, 0x20, 0x23, 0x20, 0x21, 0x20, 0x22, 0x20, 0x21, 0x20, 0x25,
646 0x30, 0x31, 0x30, 0x32, 0x30, 0x31, 0x30, 0x33, 0x30, 0x31, 0x30, 0x32, 0x30, 0x31, 0x30, 0x34,
647 0x40, 0x41, 0x40, 0x42, 0x40, 0x41, 0x40, 0x43, 0x50, 0x51, 0x50, 0x52, 0x60, 0x61, 0x70, 0x78
648};
649
650/* hdlc_unpack
651 * perform HDLC frame processing (bit unstuffing, flag detection, FCS calculation)
652 * on a sequence of received data bytes (8 bits each, LSB first)
653 * pass on successfully received, complete frames as SKBs via gigaset_rcv_skb
654 * notify of errors via gigaset_rcv_error
655 * tally frames, errors etc. in BC structure counters
656 * parameters:
657 * src received data
658 * count number of received bytes
659 * bcs receiving B channel structure
660 */
661static inline void hdlc_unpack(unsigned char *src, unsigned count,
662 struct bc_state *bcs)
663{
664 struct bas_bc_state *ubc;
665 int inputstate;
666 unsigned seqlen, inbyte, inbits;
667
668 IFNULLRET(bcs);
669 ubc = bcs->hw.bas;
670 IFNULLRET(ubc);
671
672 /* load previous state:
673 * inputstate = set of flag bits:
674 * - INS_flag_hunt: no complete opening flag received since connection setup or last abort
675 * - INS_have_data: at least one complete data byte received since last flag
676 * seqlen = number of consecutive '1' bits in last 7 input stream bits (0..7)
677 * inbyte = accumulated partial data byte (if !INS_flag_hunt)
678 * inbits = number of valid bits in inbyte, starting at LSB (0..6)
679 */
680 inputstate = bcs->inputstate;
681 seqlen = ubc->seqlen;
682 inbyte = ubc->inbyte;
683 inbits = ubc->inbits;
684
685 /* bit unstuffing a byte a time
686 * Take your time to understand this; it's straightforward but tedious.
687 * The "bitcounts" lookup table is used to speed up the counting of
688 * leading and trailing '1' bits.
689 */
690 while (count--) {
691 unsigned char c = *src++;
692 unsigned char tabentry = bitcounts[c];
693 unsigned lead1 = tabentry & 0x0f;
694 unsigned trail1 = (tabentry >> 4) & 0x0f;
695
696 seqlen += lead1;
697
698 if (unlikely(inputstate & INS_flag_hunt)) {
699 if (c == PPP_FLAG) {
700 /* flag-in-one */
701 inputstate &= ~(INS_flag_hunt | INS_have_data);
702 inbyte = 0;
703 inbits = 0;
704 } else if (seqlen == 6 && trail1 != 7) {
705 /* flag completed & not followed by abort */
706 inputstate &= ~(INS_flag_hunt | INS_have_data);
707 inbyte = c >> (lead1 + 1);
708 inbits = 7 - lead1;
709 if (trail1 >= 8) {
710 /* interior stuffing: omitting the MSB handles most cases */
711 inbits--;
712 /* correct the incorrectly handled cases individually */
713 switch (c) {
714 case 0xbe:
715 inbyte = 0x3f;
716 break;
717 }
718 }
719 }
720 /* else: continue flag-hunting */
721 } else if (likely(seqlen < 5 && trail1 < 7)) {
722 /* streamlined case: 8 data bits, no stuffing */
723 inbyte |= c << inbits;
724 hdlc_putbyte(inbyte & 0xff, bcs);
725 inputstate |= INS_have_data;
726 inbyte >>= 8;
727 /* inbits unchanged */
728 } else if (likely(seqlen == 6 && inbits == 7 - lead1 &&
729 trail1 + 1 == inbits &&
730 !(inputstate & INS_have_data))) {
731 /* streamlined case: flag idle - state unchanged */
732 } else if (unlikely(seqlen > 6)) {
733 /* abort sequence */
734 ubc->aborts++;
735 hdlc_flush(bcs);
736 inputstate |= INS_flag_hunt;
737 } else if (seqlen == 6) {
738 /* closing flag, including (6 - lead1) '1's and one '0' from inbits */
739 if (inbits > 7 - lead1) {
740 hdlc_frag(bcs, inbits + lead1 - 7);
741 inputstate &= ~INS_have_data;
742 } else {
743 if (inbits < 7 - lead1)
744 ubc->stolen0s ++;
745 if (inputstate & INS_have_data) {
746 hdlc_done(bcs);
747 inputstate &= ~INS_have_data;
748 }
749 }
750
751 if (c == PPP_FLAG) {
752 /* complete flag, LSB overlaps preceding flag */
753 ubc->shared0s ++;
754 inbits = 0;
755 inbyte = 0;
756 } else if (trail1 != 7) {
757 /* remaining bits */
758 inbyte = c >> (lead1 + 1);
759 inbits = 7 - lead1;
760 if (trail1 >= 8) {
761 /* interior stuffing: omitting the MSB handles most cases */
762 inbits--;
763 /* correct the incorrectly handled cases individually */
764 switch (c) {
765 case 0xbe:
766 inbyte = 0x3f;
767 break;
768 }
769 }
770 } else {
771 /* abort sequence follows, skb already empty anyway */
772 ubc->aborts++;
773 inputstate |= INS_flag_hunt;
774 }
775 } else { /* (seqlen < 6) && (seqlen == 5 || trail1 >= 7) */
776
777 if (c == PPP_FLAG) {
778 /* complete flag */
779 if (seqlen == 5)
780 ubc->stolen0s++;
781 if (inbits) {
782 hdlc_frag(bcs, inbits);
783 inbits = 0;
784 inbyte = 0;
785 } else if (inputstate & INS_have_data)
786 hdlc_done(bcs);
787 inputstate &= ~INS_have_data;
788 } else if (trail1 == 7) {
789 /* abort sequence */
790 ubc->aborts++;
791 hdlc_flush(bcs);
792 inputstate |= INS_flag_hunt;
793 } else {
794 /* stuffed data */
795 if (trail1 < 7) { /* => seqlen == 5 */
796 /* stuff bit at position lead1, no interior stuffing */
797 unsigned char mask = (1 << lead1) - 1;
798 c = (c & mask) | ((c & ~mask) >> 1);
799 inbyte |= c << inbits;
800 inbits += 7;
801 } else if (seqlen < 5) { /* trail1 >= 8 */
802 /* interior stuffing: omitting the MSB handles most cases */
803 /* correct the incorrectly handled cases individually */
804 switch (c) {
805 case 0xbe:
806 c = 0x7e;
807 break;
808 }
809 inbyte |= c << inbits;
810 inbits += 7;
811 } else { /* seqlen == 5 && trail1 >= 8 */
812
813 /* stuff bit at lead1 *and* interior stuffing */
814 switch (c) { /* unstuff individually */
815 case 0x7d:
816 c = 0x3f;
817 break;
818 case 0xbe:
819 c = 0x3f;
820 break;
821 case 0x3e:
822 c = 0x1f;
823 break;
824 case 0x7c:
825 c = 0x3e;
826 break;
827 }
828 inbyte |= c << inbits;
829 inbits += 6;
830 }
831 if (inbits >= 8) {
832 inbits -= 8;
833 hdlc_putbyte(inbyte & 0xff, bcs);
834 inputstate |= INS_have_data;
835 inbyte >>= 8;
836 }
837 }
838 }
839 seqlen = trail1 & 7;
840 }
841
842 /* save new state */
843 bcs->inputstate = inputstate;
844 ubc->seqlen = seqlen;
845 ubc->inbyte = inbyte;
846 ubc->inbits = inbits;
847}
848
849/* trans_receive
850 * pass on received USB frame transparently as SKB via gigaset_rcv_skb
851 * invert bytes
852 * tally frames, errors etc. in BC structure counters
853 * parameters:
854 * src received data
855 * count number of received bytes
856 * bcs receiving B channel structure
857 */
858static inline void trans_receive(unsigned char *src, unsigned count,
859 struct bc_state *bcs)
860{
861 struct sk_buff *skb;
862 int dobytes;
863 unsigned char *dst;
864
865 if (unlikely(bcs->ignore)) {
866 bcs->ignore--;
867 hdlc_flush(bcs);
868 return;
869 }
870 if (unlikely((skb = bcs->skb) == NULL)) {
871 bcs->skb = skb = dev_alloc_skb(SBUFSIZE + HW_HDR_LEN);
872 if (!skb) {
873 err("could not allocate skb");
874 return;
875 }
876 skb_reserve(skb, HW_HDR_LEN);
877 }
878 bcs->hw.bas->goodbytes += skb->len;
879 dobytes = TRANSBUFSIZE - skb->len;
880 while (count > 0) {
881 dst = skb_put(skb, count < dobytes ? count : dobytes);
882 while (count > 0 && dobytes > 0) {
883 *dst++ = gigaset_invtab[*src++];
884 count--;
885 dobytes--;
886 }
887 if (dobytes == 0) {
888 gigaset_rcv_skb(skb, bcs->cs, bcs);
889 bcs->skb = skb = dev_alloc_skb(SBUFSIZE + HW_HDR_LEN);
890 if (!skb) {
891 err("could not allocate skb");
892 return;
893 }
894 skb_reserve(bcs->skb, HW_HDR_LEN);
895 dobytes = TRANSBUFSIZE;
896 }
897 }
898}
899
900void gigaset_isoc_receive(unsigned char *src, unsigned count, struct bc_state *bcs)
901{
902 switch (bcs->proto2) {
903 case ISDN_PROTO_L2_HDLC:
904 hdlc_unpack(src, count, bcs);
905 break;
906 default: /* assume transparent */
907 trans_receive(src, count, bcs);
908 }
909}
910
911/* == data input =========================================================== */
912
913static void cmd_loop(unsigned char *src, int numbytes, struct inbuf_t *inbuf)
914{
915 struct cardstate *cs = inbuf->cs;
916 unsigned cbytes = cs->cbytes;
917
918 while (numbytes--) {
919 /* copy next character, check for end of line */
920 switch (cs->respdata[cbytes] = *src++) {
921 case '\r':
922 case '\n':
923 /* end of line */
924 dbg(DEBUG_TRANSCMD, "%s: End of Command (%d Bytes)",
925 __func__, cbytes);
926 cs->cbytes = cbytes;
927 gigaset_handle_modem_response(cs);
928 cbytes = 0;
929 break;
930 default:
931 /* advance in line buffer, checking for overflow */
932 if (cbytes < MAX_RESP_SIZE - 1)
933 cbytes++;
934 else
935 warn("response too large");
936 }
937 }
938
939 /* save state */
940 cs->cbytes = cbytes;
941}
942
943
944/* process a block of data received through the control channel
945 */
946void gigaset_isoc_input(struct inbuf_t *inbuf)
947{
948 struct cardstate *cs = inbuf->cs;
949 unsigned tail, head, numbytes;
950 unsigned char *src;
951
952 head = atomic_read(&inbuf->head);
953 while (head != (tail = atomic_read(&inbuf->tail))) {
954 dbg(DEBUG_INTR, "buffer state: %u -> %u", head, tail);
955 if (head > tail)
956 tail = RBUFSIZE;
957 src = inbuf->data + head;
958 numbytes = tail - head;
959 dbg(DEBUG_INTR, "processing %u bytes", numbytes);
960
961 if (atomic_read(&cs->mstate) == MS_LOCKED) {
962 gigaset_dbg_buffer(DEBUG_LOCKCMD, "received response",
963 numbytes, src, 0);
964 gigaset_if_receive(inbuf->cs, src, numbytes);
965 } else {
966 gigaset_dbg_buffer(DEBUG_CMD, "received response",
967 numbytes, src, 0);
968 cmd_loop(src, numbytes, inbuf);
969 }
970
971 head += numbytes;
972 if (head == RBUFSIZE)
973 head = 0;
974 dbg(DEBUG_INTR, "setting head to %u", head);
975 atomic_set(&inbuf->head, head);
976 }
977}
978
979
980/* == data output ========================================================== */
981
982/* gigaset_send_skb
983 * called by common.c to queue an skb for sending
984 * and start transmission if necessary
985 * parameters:
986 * B Channel control structure
987 * skb
988 * return value:
989 * number of bytes accepted for sending
990 * (skb->len if ok, 0 if out of buffer space)
991 * or error code (< 0, eg. -EINVAL)
992 */
993int gigaset_isoc_send_skb(struct bc_state *bcs, struct sk_buff *skb)
994{
995 int len;
996
997 IFNULLRETVAL(bcs, -EFAULT);
998 IFNULLRETVAL(skb, -EFAULT);
999 len = skb->len;
1000
1001 skb_queue_tail(&bcs->squeue, skb);
1002 dbg(DEBUG_ISO,
1003 "%s: skb queued, qlen=%d", __func__, skb_queue_len(&bcs->squeue));
1004
1005 /* tasklet submits URB if necessary */
1006 tasklet_schedule(&bcs->hw.bas->sent_tasklet);
1007
1008 return len; /* ok so far */
1009}
Linux kernel - Deliverables
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