drivers/isdn/gigaset/asyncdata.c

   1 /*
   2  * Common data handling layer for ser_gigaset and usb_gigaset
   3  *
   4  * Copyright (c) 2005 by Tilman Schmidt <tilman@imap.cc>,
   5  *                       Hansjoerg Lipp <hjlipp@web.de>,
   6  *                       Stefan Eilers <Eilers.Stefan@epost.de>.
   7  *
   8  * =====================================================================
   9  *      This program is free software; you can redistribute it and/or
  10  *      modify it under the terms of the GNU General Public License as
  11  *      published by the Free Software Foundation; either version 2 of
  12  *      the License, or (at your option) any later version.
  13  * =====================================================================
  14  * ToDo: ...
  15  * =====================================================================
  16  * Version: $Id: asyncdata.c,v 1.2.2.7 2005/11/13 23:05:18 hjlipp Exp $
  17  * =====================================================================
  18  */
  19
  20 #include "gigaset.h"
  21 #include <linux/crc-ccitt.h>
  22
  23 //#define GIG_M10x_STUFF_VOICE_DATA
  24
  25 /* check if byte must be stuffed/escaped
  26  * I'm not sure which data should be encoded.
  27  * Therefore I will go the hard way and decode every value
  28  * less than 0x20, the flag sequence and the control escape char.
  29  */
  30 static inline int muststuff(unsigned char c)
  31 {
  32         if (c < PPP_TRANS) return 1;
  33         if (c == PPP_FLAG) return 1;
  34         if (c == PPP_ESCAPE) return 1;
  35         /* other possible candidates: */
  36         /* 0x91: XON with parity set */
  37         /* 0x93: XOFF with parity set */
  38         return 0;
  39 }
  40
  41 /* == data input =========================================================== */
  42
  43 /* process a block of received bytes in command mode (modem response)
  44  * Return value:
  45  *      number of processed bytes
  46  */
  47 static inline int cmd_loop(unsigned char c, unsigned char *src, int numbytes,
  48                            struct inbuf_t *inbuf)
  49 {
  50         struct cardstate *cs = inbuf->cs;
  51         unsigned cbytes      = cs->cbytes;
  52         int inputstate = inbuf->inputstate;
  53         int startbytes = numbytes;
  54
  55         for (;;) {
  56                 cs->respdata[cbytes] = c;
  57                 if (c == 10 || c == 13) {
  58                         dbg(DEBUG_TRANSCMD, "%s: End of Command (%d Bytes)",
  59                             __func__, cbytes);
  60                         cs->cbytes = cbytes;
  61                         gigaset_handle_modem_response(cs); /* can change cs->dle */
  62                         cbytes = 0;
  63
  64                         if (cs->dle &&
  65                             !(inputstate & INS_DLE_command)) {
  66                                 inputstate &= ~INS_command;
  67                                 break;
  68                         }
  69                 } else {
  70                         /* advance in line buffer, checking for overflow */
  71                         if (cbytes < MAX_RESP_SIZE - 1)
  72                                 cbytes++;
  73                         else
  74                                 warn("response too large");
  75                 }
  76
  77                 if (!numbytes)
  78                         break;
  79                 c = *src++;
  80                 --numbytes;
  81                 if (c == DLE_FLAG &&
  82                     (cs->dle || inputstate & INS_DLE_command)) {
  83                         inputstate |= INS_DLE_char;
  84                         break;
  85                 }
  86         }
  87
  88         cs->cbytes = cbytes;
  89         inbuf->inputstate = inputstate;
  90
  91         return startbytes - numbytes;
  92 }
  93
  94 /* process a block of received bytes in lock mode (tty i/f)
  95  * Return value:
  96  *      number of processed bytes
  97  */
  98 static inline int lock_loop(unsigned char *src, int numbytes,
  99                             struct inbuf_t *inbuf)
 100 {
 101         struct cardstate *cs = inbuf->cs;
 102
 103         gigaset_dbg_buffer(DEBUG_LOCKCMD, "received response", numbytes, src, 0);
 104         gigaset_if_receive(cs, src, numbytes);
 105
 106         return numbytes;
 107 }
 108
 109 /* process a block of received bytes in HDLC data mode
 110  * Collect HDLC frames, undoing byte stuffing and watching for DLE escapes.
 111  * When a frame is complete, check the FCS and pass valid frames to the LL.
 112  * If DLE is encountered, return immediately to let the caller handle it.
 113  * Return value:
 114  *      number of processed bytes
 115  *      numbytes (all bytes processed) on error --FIXME
 116  */
 117 static inline int hdlc_loop(unsigned char c, unsigned char *src, int numbytes,
 118                             struct inbuf_t *inbuf)
 119 {
 120         struct cardstate *cs = inbuf->cs;
 121         struct bc_state *bcs = inbuf->bcs;
 122         int inputstate;
 123         __u16 fcs;
 124         struct sk_buff *skb;
 125         unsigned char error;
 126         struct sk_buff *compskb;
 127         int startbytes = numbytes;
 128         int l;
 129
 130         IFNULLRETVAL(bcs, numbytes);
 131         inputstate = bcs->inputstate;
 132         fcs = bcs->fcs;
 133         skb = bcs->skb;
 134         IFNULLRETVAL(skb, numbytes);
 135
 136         if (unlikely(inputstate & INS_byte_stuff)) {
 137                 inputstate &= ~INS_byte_stuff;
 138                 goto byte_stuff;
 139         }
 140         for (;;) {
 141                 if (unlikely(c == PPP_ESCAPE)) {
 142                         if (unlikely(!numbytes)) {
 143                                 inputstate |= INS_byte_stuff;
 144                                 break;
 145                         }
 146                         c = *src++;
 147                         --numbytes;
 148                         if (unlikely(c == DLE_FLAG &&
 149                                      (cs->dle ||
 150                                       inbuf->inputstate & INS_DLE_command))) {
 151                                 inbuf->inputstate |= INS_DLE_char;
 152                                 inputstate |= INS_byte_stuff;
 153                                 break;
 154                         }
 155 byte_stuff:
 156                         c ^= PPP_TRANS;
 157 #ifdef CONFIG_GIGASET_DEBUG
 158                         if (unlikely(!muststuff(c)))
 159                                 dbg(DEBUG_HDLC,
 160                                     "byte stuffed: 0x%02x", c);
 161 #endif
 162                 } else if (unlikely(c == PPP_FLAG)) {
 163                         if (unlikely(inputstate & INS_skip_frame)) {
 164                                 if (!(inputstate & INS_have_data)) { /* 7E 7E */
 165                                         //dbg(DEBUG_HDLC, "(7e)7e------------------------");
 166 #ifdef CONFIG_GIGASET_DEBUG
 167                                         ++bcs->emptycount;
 168 #endif
 169                                 } else
 170                                         dbg(DEBUG_HDLC,
 171                                             "7e----------------------------");
 172
 173                                 /* end of frame */
 174                                 error = 1;
 175                                 gigaset_rcv_error(NULL, cs, bcs);
 176                         } else if (!(inputstate & INS_have_data)) { /* 7E 7E */
 177                                 //dbg(DEBUG_HDLC, "(7e)7e------------------------");
 178 #ifdef CONFIG_GIGASET_DEBUG
 179                                 ++bcs->emptycount;
 180 #endif
 181                                 break;
 182                         } else {
 183                                 dbg(DEBUG_HDLC,
 184                                     "7e----------------------------");
 185
 186                                 /* end of frame */
 187                                 error = 0;
 188
 189                                 if (unlikely(fcs != PPP_GOODFCS)) {
 190                                         err("Packet checksum at %lu failed, "
 191                                             "packet is corrupted (%u bytes)!",
 192                                             bcs->rcvbytes, skb->len);
 193                                         compskb = NULL;
 194                                         gigaset_rcv_error(compskb, cs, bcs);
 195                                         error = 1;
 196                                 } else {
 197                                         if (likely((l = skb->len) > 2)) {
 198                                                 skb->tail -= 2;
 199                                                 skb->len -= 2;
 200                                         } else {
 201                                                 dev_kfree_skb(skb);
 202                                                 skb = NULL;
 203                                                 inputstate |= INS_skip_frame;
 204                                                 if (l == 1) {
 205                                                         err("invalid packet size (1)!");
 206                                                         error = 1;
 207                                                         gigaset_rcv_error(NULL, cs, bcs);
 208                                                 }
 209                                         }
 210                                         if (likely(!(error ||
 211                                                      (inputstate &
 212                                                       INS_skip_frame)))) {
 213                                                 gigaset_rcv_skb(skb, cs, bcs);
 214                                         }
 215                                 }
 216                         }
 217
 218                         if (unlikely(error))
 219                                 if (skb)
 220                                         dev_kfree_skb(skb);
 221
 222                         fcs = PPP_INITFCS;
 223                         inputstate &= ~(INS_have_data | INS_skip_frame);
 224                         if (unlikely(bcs->ignore)) {
 225                                 inputstate |= INS_skip_frame;
 226                                 skb = NULL;
 227                         } else if (likely((skb = dev_alloc_skb(SBUFSIZE + HW_HDR_LEN)) != NULL)) {
 228                                 skb_reserve(skb, HW_HDR_LEN);
 229                         } else {
 230                                 warn("could not allocate new skb");
 231                                 inputstate |= INS_skip_frame;
 232                         }
 233
 234                         break;
 235 #ifdef CONFIG_GIGASET_DEBUG
 236                 } else if (unlikely(muststuff(c))) {
 237                         /* Should not happen. Possible after ZDLE=1<CR><LF>. */
 238                         dbg(DEBUG_HDLC, "not byte stuffed: 0x%02x", c);
 239 #endif
 240                 }
 241
 242                 /* add character */
 243
 244 #ifdef CONFIG_GIGASET_DEBUG
 245                 if (unlikely(!(inputstate & INS_have_data))) {
 246                         dbg(DEBUG_HDLC,
 247                             "7e (%d x) ================", bcs->emptycount);
 248                         bcs->emptycount = 0;
 249                 }
 250 #endif
 251
 252                 inputstate |= INS_have_data;
 253
 254                 if (likely(!(inputstate & INS_skip_frame))) {
 255                         if (unlikely(skb->len == SBUFSIZE)) {
 256                                 warn("received packet too long");
 257                                 dev_kfree_skb_any(skb);
 258                                 skb = NULL;
 259                                 inputstate |= INS_skip_frame;
 260                                 break;
 261                         }
 262                         *gigaset_skb_put_quick(skb, 1) = c;
 263                         /* *__skb_put (skb, 1) = c; */
 264                         fcs = crc_ccitt_byte(fcs, c);
 265                 }
 266
 267                 if (unlikely(!numbytes))
 268                         break;
 269                 c = *src++;
 270                 --numbytes;
 271                 if (unlikely(c == DLE_FLAG &&
 272                              (cs->dle ||
 273                               inbuf->inputstate & INS_DLE_command))) {
 274                         inbuf->inputstate |= INS_DLE_char;
 275                         break;
 276                 }
 277         }
 278         bcs->inputstate = inputstate;
 279         bcs->fcs = fcs;
 280         bcs->skb = skb;
 281         return startbytes - numbytes;
 282 }
 283
 284 /* process a block of received bytes in transparent data mode
 285  * Invert bytes, undoing byte stuffing and watching for DLE escapes.
 286  * If DLE is encountered, return immediately to let the caller handle it.
 287  * Return value:
 288  *      number of processed bytes
 289  *      numbytes (all bytes processed) on error --FIXME
 290  */
 291 static inline int iraw_loop(unsigned char c, unsigned char *src, int numbytes,
 292                             struct inbuf_t *inbuf)
 293 {
 294         struct cardstate *cs = inbuf->cs;
 295         struct bc_state *bcs = inbuf->bcs;
 296         int inputstate;
 297         struct sk_buff *skb;
 298         int startbytes = numbytes;
 299
 300         IFNULLRETVAL(bcs, numbytes);
 301         inputstate = bcs->inputstate;
 302         skb = bcs->skb;
 303         IFNULLRETVAL(skb, numbytes);
 304
 305         for (;;) {
 306                 /* add character */
 307                 inputstate |= INS_have_data;
 308
 309                 if (likely(!(inputstate & INS_skip_frame))) {
 310                         if (unlikely(skb->len == SBUFSIZE)) {
 311                                 //FIXME just pass skb up and allocate a new one
 312                                 warn("received packet too long");
 313                                 dev_kfree_skb_any(skb);
 314                                 skb = NULL;
 315                                 inputstate |= INS_skip_frame;
 316                                 break;
 317                         }
 318                         *gigaset_skb_put_quick(skb, 1) = gigaset_invtab[c];
 319                 }
 320
 321                 if (unlikely(!numbytes))
 322                         break;
 323                 c = *src++;
 324                 --numbytes;
 325                 if (unlikely(c == DLE_FLAG &&
 326                              (cs->dle ||
 327                               inbuf->inputstate & INS_DLE_command))) {
 328                         inbuf->inputstate |= INS_DLE_char;
 329                         break;
 330                 }
 331         }
 332
 333         /* pass data up */
 334         if (likely(inputstate & INS_have_data)) {
 335                 if (likely(!(inputstate & INS_skip_frame))) {
 336                         gigaset_rcv_skb(skb, cs, bcs);
 337                 }
 338                 inputstate &= ~(INS_have_data | INS_skip_frame);
 339                 if (unlikely(bcs->ignore)) {
 340                         inputstate |= INS_skip_frame;
 341                         skb = NULL;
 342                 } else if (likely((skb = dev_alloc_skb(SBUFSIZE + HW_HDR_LEN))
 343                                   != NULL)) {
 344                         skb_reserve(skb, HW_HDR_LEN);
 345                 } else {
 346                         warn("could not allocate new skb");
 347                         inputstate |= INS_skip_frame;
 348                 }
 349         }
 350
 351         bcs->inputstate = inputstate;
 352         bcs->skb = skb;
 353         return startbytes - numbytes;
 354 }
 355
 356 /* process a block of data received from the device
 357  */
 358 void gigaset_m10x_input(struct inbuf_t *inbuf)
 359 {
 360         struct cardstate *cs;
 361         unsigned tail, head, numbytes;
 362         unsigned char *src, c;
 363         int procbytes;
 364
 365         head = atomic_read(&inbuf->head);
 366         tail = atomic_read(&inbuf->tail);
 367         dbg(DEBUG_INTR, "buffer state: %u -> %u", head, tail);
 368
 369         if (head != tail) {
 370                 cs = inbuf->cs;
 371                 src = inbuf->data + head;
 372                 numbytes = (head > tail ? RBUFSIZE : tail) - head;
 373                 dbg(DEBUG_INTR, "processing %u bytes", numbytes);
 374
 375                 while (numbytes) {
 376                         if (atomic_read(&cs->mstate) == MS_LOCKED) {
 377                                 procbytes = lock_loop(src, numbytes, inbuf);
 378                                 src += procbytes;
 379                                 numbytes -= procbytes;
 380                         } else {
 381                                 c = *src++;
 382                                 --numbytes;
 383                                 if (c == DLE_FLAG && (cs->dle ||
 384                                     inbuf->inputstate & INS_DLE_command)) {
 385                                         if (!(inbuf->inputstate & INS_DLE_char)) {
 386                                                 inbuf->inputstate |= INS_DLE_char;
 387                                                 goto nextbyte;
 388                                         }
 389                                         /* <DLE> <DLE> => <DLE> in data stream */
 390                                         inbuf->inputstate &= ~INS_DLE_char;
 391                                 }
 392
 393                                 if (!(inbuf->inputstate & INS_DLE_char)) {
 394
 395                                         /* FIXME Einfach je nach Modus Funktionszeiger in cs setzen [hier+hdlc_loop]?  */
 396                                         /* FIXME Spart folgendes "if" und ermoeglicht andere Protokolle */
 397                                         if (inbuf->inputstate & INS_command)
 398                                                 procbytes = cmd_loop(c, src, numbytes, inbuf);
 399                                         else if (inbuf->bcs->proto2 == ISDN_PROTO_L2_HDLC)
 400                                                 procbytes = hdlc_loop(c, src, numbytes, inbuf);
 401                                         else
 402                                                 procbytes = iraw_loop(c, src, numbytes, inbuf);
 403
 404                                         src += procbytes;
 405                                         numbytes -= procbytes;
 406                                 } else {  /* DLE-char */
 407                                         inbuf->inputstate &= ~INS_DLE_char;
 408                                         switch (c) {
 409                                         case 'X': /*begin of command*/
 410 #ifdef CONFIG_GIGASET_DEBUG
 411                                                 if (inbuf->inputstate & INS_command)
 412                                                         err("received <DLE> 'X' in command mode");
 413 #endif
 414                                                 inbuf->inputstate |=
 415                                                         INS_command | INS_DLE_command;
 416                                                 break;
 417                                         case '.': /*end of command*/
 418 #ifdef CONFIG_GIGASET_DEBUG
 419                                                 if (!(inbuf->inputstate & INS_command))
 420                                                         err("received <DLE> '.' in hdlc mode");
 421 #endif
 422                                                 inbuf->inputstate &= cs->dle ?
 423                                                         ~(INS_DLE_command|INS_command)
 424                                                         : ~INS_DLE_command;
 425                                                 break;
 426                                         //case DLE_FLAG: /*DLE_FLAG in data stream*/ /* schon oben behandelt! */
 427                                         default:
 428                                                 err("received 0x10 0x%02x!", (int) c);
 429                                                 /* FIXME: reset driver?? */
 430                                         }
 431                                 }
 432                         }
 433 nextbyte:
 434                         if (!numbytes) {
 435                                 /* end of buffer, check for wrap */
 436                                 if (head > tail) {
 437                                         head = 0;
 438                                         src = inbuf->data;
 439                                         numbytes = tail;
 440                                 } else {
 441                                         head = tail;
 442                                         break;
 443                                 }
 444                         }
 445                 }
 446
 447                 dbg(DEBUG_INTR, "setting head to %u", head);
 448                 atomic_set(&inbuf->head, head);
 449         }
 450 }
 451
 452
 453 /* == data output ========================================================== */
 454
 455 /* Encoding of a PPP packet into an octet stuffed HDLC frame
 456  * with FCS, opening and closing flags.
 457  * parameters:
 458  *      skb     skb containing original packet (freed upon return)
 459  *      head    number of headroom bytes to allocate in result skb
 460  *      tail    number of tailroom bytes to allocate in result skb
 461  * Return value:
 462  *      pointer to newly allocated skb containing the result frame
 463  */
 464 static struct sk_buff *HDLC_Encode(struct sk_buff *skb, int head, int tail)
 465 {
 466         struct sk_buff *hdlc_skb;
 467         __u16 fcs;
 468         unsigned char c;
 469         unsigned char *cp;
 470         int len;
 471         unsigned int stuf_cnt;
 472
 473         stuf_cnt = 0;
 474         fcs = PPP_INITFCS;
 475         cp = skb->data;
 476         len = skb->len;
 477         while (len--) {
 478                 if (muststuff(*cp))
 479                         stuf_cnt++;
 480                 fcs = crc_ccitt_byte(fcs, *cp++);
 481         }
 482         fcs ^= 0xffff;                 /* complement */
 483
 484         /* size of new buffer: original size + number of stuffing bytes
 485          * + 2 bytes FCS + 2 stuffing bytes for FCS (if needed) + 2 flag bytes
 486          */
 487         hdlc_skb = dev_alloc_skb(skb->len + stuf_cnt + 6 + tail + head);
 488         if (!hdlc_skb) {
 489                 err("unable to allocate memory for HDLC encoding!");
 490                 dev_kfree_skb(skb);
 491                 return NULL;
 492         }
 493         skb_reserve(hdlc_skb, head);
 494
 495         /* Copy acknowledge request into new skb */
 496         memcpy(hdlc_skb->head, skb->head, 2);
 497
 498         /* Add flag sequence in front of everything.. */
 499         *(skb_put(hdlc_skb, 1)) = PPP_FLAG;
 500
 501         /* Perform byte stuffing while copying data. */
 502         while (skb->len--) {
 503                 if (muststuff(*skb->data)) {
 504                         *(skb_put(hdlc_skb, 1)) = PPP_ESCAPE;
 505                         *(skb_put(hdlc_skb, 1)) = (*skb->data++) ^ PPP_TRANS;
 506                 } else
 507                         *(skb_put(hdlc_skb, 1)) = *skb->data++;
 508         }
 509
 510         /* Finally add FCS (byte stuffed) and flag sequence */
 511         c = (fcs & 0x00ff);      /* least significant byte first */
 512         if (muststuff(c)) {
 513                 *(skb_put(hdlc_skb, 1)) = PPP_ESCAPE;
 514                 c ^= PPP_TRANS;
 515         }
 516         *(skb_put(hdlc_skb, 1)) = c;
 517
 518         c = ((fcs >> 8) & 0x00ff);
 519         if (muststuff(c)) {
 520                 *(skb_put(hdlc_skb, 1)) = PPP_ESCAPE;
 521                 c ^= PPP_TRANS;
 522         }
 523         *(skb_put(hdlc_skb, 1)) = c;
 524
 525         *(skb_put(hdlc_skb, 1)) = PPP_FLAG;
 526
 527         dev_kfree_skb(skb);
 528         return hdlc_skb;
 529 }
 530
 531 /* Encoding of a raw packet into an octet stuffed bit inverted frame
 532  * parameters:
 533  *      skb     skb containing original packet (freed upon return)
 534  *      head    number of headroom bytes to allocate in result skb
 535  *      tail    number of tailroom bytes to allocate in result skb
 536  * Return value:
 537  *      pointer to newly allocated skb containing the result frame
 538  */
 539 static struct sk_buff *iraw_encode(struct sk_buff *skb, int head, int tail)
 540 {
 541         struct sk_buff *iraw_skb;
 542         unsigned char c;
 543         unsigned char *cp;
 544         int len;
 545
 546         /* worst case: every byte must be stuffed */
 547         iraw_skb = dev_alloc_skb(2*skb->len + tail + head);
 548         if (!iraw_skb) {
 549                 err("unable to allocate memory for HDLC encoding!");
 550                 dev_kfree_skb(skb);
 551                 return NULL;
 552         }
 553         skb_reserve(iraw_skb, head);
 554
 555         cp = skb->data;
 556         len = skb->len;
 557         while (len--) {
 558                 c = gigaset_invtab[*cp++];
 559                 if (c == DLE_FLAG)
 560                         *(skb_put(iraw_skb, 1)) = c;
 561                 *(skb_put(iraw_skb, 1)) = c;
 562         }
 563         dev_kfree_skb(skb);
 564         return iraw_skb;
 565 }
 566
 567 /* gigaset_send_skb
 568  * called by common.c to queue an skb for sending
 569  * and start transmission if necessary
 570  * parameters:
 571  *      B Channel control structure
 572  *      skb
 573  * Return value:
 574  *      number of bytes accepted for sending
 575  *      (skb->len if ok, 0 if out of buffer space)
 576  *      or error code (< 0, eg. -EINVAL)
 577  */
 578 int gigaset_m10x_send_skb(struct bc_state *bcs, struct sk_buff *skb)
 579 {
 580         unsigned len;
 581
 582         IFNULLRETVAL(bcs, -EFAULT);
 583         IFNULLRETVAL(skb, -EFAULT);
 584         len = skb->len;
 585
 586         if (bcs->proto2 == ISDN_PROTO_L2_HDLC)
 587                 skb = HDLC_Encode(skb, HW_HDR_LEN, 0);
 588         else
 589                 skb = iraw_encode(skb, HW_HDR_LEN, 0);
 590         if (!skb)
 591                 return -ENOMEM;
 592
 593         skb_queue_tail(&bcs->squeue, skb);
 594         tasklet_schedule(&bcs->cs->write_tasklet);
 595
 596         return len;     /* ok so far */
 597 }