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.
   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  */
  15
  16 /* not set by Kbuild when building both ser_gigaset and usb_gigaset */
  17 #ifndef KBUILD_MODNAME
  18 #define KBUILD_MODNAME "asy_gigaset"
  19 #endif
  20
  21 #include "gigaset.h"
  22 #include <linux/crc-ccitt.h>
  23 #include <linux/bitrev.h>
  24
  25 //#define GIG_M10x_STUFF_VOICE_DATA
  26
  27 /* check if byte must be stuffed/escaped
  28  * I'm not sure which data should be encoded.
  29  * Therefore I will go the hard way and decode every value
  30  * less than 0x20, the flag sequence and the control escape char.
  31  */
  32 static inline int muststuff(unsigned char c)
  33 {
  34         if (c < PPP_TRANS) return 1;
  35         if (c == PPP_FLAG) return 1;
  36         if (c == PPP_ESCAPE) return 1;
  37         /* other possible candidates: */
  38         /* 0x91: XON with parity set */
  39         /* 0x93: XOFF with parity set */
  40         return 0;
  41 }
  42
  43 /* == data input =========================================================== */
  44
  45 /* process a block of received bytes in command mode (modem response)
  46  * Return value:
  47  *      number of processed bytes
  48  */
  49 static inline int cmd_loop(unsigned char c, unsigned char *src, int numbytes,
  50                            struct inbuf_t *inbuf)
  51 {
  52         struct cardstate *cs = inbuf->cs;
  53         unsigned cbytes      = cs->cbytes;
  54         int inputstate = inbuf->inputstate;
  55         int startbytes = numbytes;
  56
  57         for (;;) {
  58                 cs->respdata[cbytes] = c;
  59                 if (c == 10 || c == 13) {
  60                         gig_dbg(DEBUG_TRANSCMD, "%s: End of Command (%d Bytes)",
  61                                 __func__, cbytes);
  62                         cs->cbytes = cbytes;
  63                         gigaset_handle_modem_response(cs); /* can change
  64                                                               cs->dle */
  65                         cbytes = 0;
  66
  67                         if (cs->dle &&
  68                             !(inputstate & INS_DLE_command)) {
  69                                 inputstate &= ~INS_command;
  70                                 break;
  71                         }
  72                 } else {
  73                         /* advance in line buffer, checking for overflow */
  74                         if (cbytes < MAX_RESP_SIZE - 1)
  75                                 cbytes++;
  76                         else
  77                                 dev_warn(cs->dev, "response too large\n");
  78                 }
  79
  80                 if (!numbytes)
  81                         break;
  82                 c = *src++;
  83                 --numbytes;
  84                 if (c == DLE_FLAG &&
  85                     (cs->dle || inputstate & INS_DLE_command)) {
  86                         inputstate |= INS_DLE_char;
  87                         break;
  88                 }
  89         }
  90
  91         cs->cbytes = cbytes;
  92         inbuf->inputstate = inputstate;
  93
  94         return startbytes - numbytes;
  95 }
  96
  97 /* process a block of received bytes in lock mode (tty i/f)
  98  * Return value:
  99  *      number of processed bytes
 100  */
 101 static inline int lock_loop(unsigned char *src, int numbytes,
 102                             struct inbuf_t *inbuf)
 103 {
 104         struct cardstate *cs = inbuf->cs;
 105
 106         gigaset_dbg_buffer(DEBUG_LOCKCMD, "received response",
 107                            numbytes, src);
 108         gigaset_if_receive(cs, src, numbytes);
 109
 110         return numbytes;
 111 }
 112
 113 /* process a block of received bytes in HDLC data mode
 114  * Collect HDLC frames, undoing byte stuffing and watching for DLE escapes.
 115  * When a frame is complete, check the FCS and pass valid frames to the LL.
 116  * If DLE is encountered, return immediately to let the caller handle it.
 117  * Return value:
 118  *      number of processed bytes
 119  *      numbytes (all bytes processed) on error --FIXME
 120  */
 121 static inline int hdlc_loop(unsigned char c, unsigned char *src, int numbytes,
 122                             struct inbuf_t *inbuf)
 123 {
 124         struct cardstate *cs = inbuf->cs;
 125         struct bc_state *bcs = inbuf->bcs;
 126         int inputstate = bcs->inputstate;
 127         __u16 fcs = bcs->fcs;
 128         struct sk_buff *skb = bcs->skb;
 129         unsigned char error;
 130         struct sk_buff *compskb;
 131         int startbytes = numbytes;
 132         int l;
 133
 134         if (unlikely(inputstate & INS_byte_stuff)) {
 135                 inputstate &= ~INS_byte_stuff;
 136                 goto byte_stuff;
 137         }
 138         for (;;) {
 139                 if (unlikely(c == PPP_ESCAPE)) {
 140                         if (unlikely(!numbytes)) {
 141                                 inputstate |= INS_byte_stuff;
 142                                 break;
 143                         }
 144                         c = *src++;
 145                         --numbytes;
 146                         if (unlikely(c == DLE_FLAG &&
 147                                      (cs->dle ||
 148                                       inbuf->inputstate & INS_DLE_command))) {
 149                                 inbuf->inputstate |= INS_DLE_char;
 150                                 inputstate |= INS_byte_stuff;
 151                                 break;
 152                         }
 153 byte_stuff:
 154                         c ^= PPP_TRANS;
 155 #ifdef CONFIG_GIGASET_DEBUG
 156                         if (unlikely(!muststuff(c)))
 157                                 gig_dbg(DEBUG_HDLC, "byte stuffed: 0x%02x", c);
 158 #endif
 159                 } else if (unlikely(c == PPP_FLAG)) {
 160                         if (unlikely(inputstate & INS_skip_frame)) {
 161                                 if (!(inputstate & INS_have_data)) { /* 7E 7E */
 162 #ifdef CONFIG_GIGASET_DEBUG
 163                                         ++bcs->emptycount;
 164 #endif
 165                                 } else
 166                                         gig_dbg(DEBUG_HDLC,
 167                                             "7e----------------------------");
 168
 169                                 /* end of frame */
 170                                 error = 1;
 171                                 gigaset_rcv_error(NULL, cs, bcs);
 172                         } else if (!(inputstate & INS_have_data)) { /* 7E 7E */
 173 #ifdef CONFIG_GIGASET_DEBUG
 174                                 ++bcs->emptycount;
 175 #endif
 176                                 break;
 177                         } else {
 178                                 gig_dbg(DEBUG_HDLC,
 179                                         "7e----------------------------");
 180
 181                                 /* end of frame */
 182                                 error = 0;
 183
 184                                 if (unlikely(fcs != PPP_GOODFCS)) {
 185                                         dev_err(cs->dev,
 186                                             "Packet checksum at %lu failed, "
 187                                             "packet is corrupted (%u bytes)!\n",
 188                                             bcs->rcvbytes, skb->len);
 189                                         compskb = NULL;
 190                                         gigaset_rcv_error(compskb, cs, bcs);
 191                                         error = 1;
 192                                 } else {
 193                                         if (likely((l = skb->len) > 2)) {
 194                                                 skb->tail -= 2;
 195                                                 skb->len -= 2;
 196                                         } else {
 197                                                 dev_kfree_skb(skb);
 198                                                 skb = NULL;
 199                                                 inputstate |= INS_skip_frame;
 200                                                 if (l == 1) {
 201                                                         dev_err(cs->dev,
 202                                                   "invalid packet size (1)!\n");
 203                                                         error = 1;
 204                                                         gigaset_rcv_error(NULL,
 205                                                                 cs, bcs);
 206                                                 }
 207                                         }
 208                                         if (likely(!(error ||
 209                                                      (inputstate &
 210                                                       INS_skip_frame)))) {
 211                                                 gigaset_rcv_skb(skb, cs, bcs);
 212                                         }
 213                                 }
 214                         }
 215
 216                         if (unlikely(error))
 217                                 if (skb)
 218                                         dev_kfree_skb(skb);
 219
 220                         fcs = PPP_INITFCS;
 221                         inputstate &= ~(INS_have_data | INS_skip_frame);
 222                         if (unlikely(bcs->ignore)) {
 223                                 inputstate |= INS_skip_frame;
 224                                 skb = NULL;
 225                         } else if (likely((skb = dev_alloc_skb(SBUFSIZE + HW_HDR_LEN)) != NULL)) {
 226                                 skb_reserve(skb, HW_HDR_LEN);
 227                         } else {
 228                                 dev_warn(cs->dev,
 229                                          "could not allocate new skb\n");
 230                                 inputstate |= INS_skip_frame;
 231                         }
 232
 233                         break;
 234 #ifdef CONFIG_GIGASET_DEBUG
 235                 } else if (unlikely(muststuff(c))) {
 236                         /* Should not happen. Possible after ZDLE=1<CR><LF>. */
 237                         gig_dbg(DEBUG_HDLC, "not byte stuffed: 0x%02x", c);
 238 #endif
 239                 }
 240
 241                 /* add character */
 242
 243 #ifdef CONFIG_GIGASET_DEBUG
 244                 if (unlikely(!(inputstate & INS_have_data))) {
 245                         gig_dbg(DEBUG_HDLC, "7e (%d x) ================",
 246                                 bcs->emptycount);
 247                         bcs->emptycount = 0;
 248                 }
 249 #endif
 250
 251                 inputstate |= INS_have_data;
 252
 253                 if (likely(!(inputstate & INS_skip_frame))) {
 254                         if (unlikely(skb->len == SBUFSIZE)) {
 255                                 dev_warn(cs->dev, "received packet too long\n");
 256                                 dev_kfree_skb_any(skb);
 257                                 skb = NULL;
 258                                 inputstate |= INS_skip_frame;
 259                                 break;
 260                         }
 261                         *__skb_put(skb, 1) = c;
 262                         fcs = crc_ccitt_byte(fcs, c);
 263                 }
 264
 265                 if (unlikely(!numbytes))
 266                         break;
 267                 c = *src++;
 268                 --numbytes;
 269                 if (unlikely(c == DLE_FLAG &&
 270                              (cs->dle ||
 271                               inbuf->inputstate & INS_DLE_command))) {
 272                         inbuf->inputstate |= INS_DLE_char;
 273                         break;
 274                 }
 275         }
 276         bcs->inputstate = inputstate;
 277         bcs->fcs = fcs;
 278         bcs->skb = skb;
 279         return startbytes - numbytes;
 280 }
 281
 282 /* process a block of received bytes in transparent data mode
 283  * Invert bytes, undoing byte stuffing and watching for DLE escapes.
 284  * If DLE is encountered, return immediately to let the caller handle it.
 285  * Return value:
 286  *      number of processed bytes
 287  *      numbytes (all bytes processed) on error --FIXME
 288  */
 289 static inline int iraw_loop(unsigned char c, unsigned char *src, int numbytes,
 290                             struct inbuf_t *inbuf)
 291 {
 292         struct cardstate *cs = inbuf->cs;
 293         struct bc_state *bcs = inbuf->bcs;
 294         int inputstate = bcs->inputstate;
 295         struct sk_buff *skb = bcs->skb;
 296         int startbytes = numbytes;
 297
 298         for (;;) {
 299                 /* add character */
 300                 inputstate |= INS_have_data;
 301
 302                 if (likely(!(inputstate & INS_skip_frame))) {
 303                         if (unlikely(skb->len == SBUFSIZE)) {
 304                                 //FIXME just pass skb up and allocate a new one
 305                                 dev_warn(cs->dev, "received packet too long\n");
 306                                 dev_kfree_skb_any(skb);
 307                                 skb = NULL;
 308                                 inputstate |= INS_skip_frame;
 309                                 break;
 310                         }
 311                         *__skb_put(skb, 1) = bitrev8(c);
 312                 }
 313
 314                 if (unlikely(!numbytes))
 315                         break;
 316                 c = *src++;
 317                 --numbytes;
 318                 if (unlikely(c == DLE_FLAG &&
 319                              (cs->dle ||
 320                               inbuf->inputstate & INS_DLE_command))) {
 321                         inbuf->inputstate |= INS_DLE_char;
 322                         break;
 323                 }
 324         }
 325
 326         /* pass data up */
 327         if (likely(inputstate & INS_have_data)) {
 328                 if (likely(!(inputstate & INS_skip_frame))) {
 329                         gigaset_rcv_skb(skb, cs, bcs);
 330                 }
 331                 inputstate &= ~(INS_have_data | INS_skip_frame);
 332                 if (unlikely(bcs->ignore)) {
 333                         inputstate |= INS_skip_frame;
 334                         skb = NULL;
 335                 } else if (likely((skb = dev_alloc_skb(SBUFSIZE + HW_HDR_LEN))
 336                                   != NULL)) {
 337                         skb_reserve(skb, HW_HDR_LEN);
 338                 } else {
 339                         dev_warn(cs->dev, "could not allocate new skb\n");
 340                         inputstate |= INS_skip_frame;
 341                 }
 342         }
 343
 344         bcs->inputstate = inputstate;
 345         bcs->skb = skb;
 346         return startbytes - numbytes;
 347 }
 348
 349 /* process a block of data received from the device
 350  */
 351 void gigaset_m10x_input(struct inbuf_t *inbuf)
 352 {
 353         struct cardstate *cs;
 354         unsigned tail, head, numbytes;
 355         unsigned char *src, c;
 356         int procbytes;
 357
 358         head = atomic_read(&inbuf->head);
 359         tail = atomic_read(&inbuf->tail);
 360         gig_dbg(DEBUG_INTR, "buffer state: %u -> %u", head, tail);
 361
 362         if (head != tail) {
 363                 cs = inbuf->cs;
 364                 src = inbuf->data + head;
 365                 numbytes = (head > tail ? RBUFSIZE : tail) - head;
 366                 gig_dbg(DEBUG_INTR, "processing %u bytes", numbytes);
 367
 368                 while (numbytes) {
 369                         if (atomic_read(&cs->mstate) == MS_LOCKED) {
 370                                 procbytes = lock_loop(src, numbytes, inbuf);
 371                                 src += procbytes;
 372                                 numbytes -= procbytes;
 373                         } else {
 374                                 c = *src++;
 375                                 --numbytes;
 376                                 if (c == DLE_FLAG && (cs->dle ||
 377                                     inbuf->inputstate & INS_DLE_command)) {
 378                                         if (!(inbuf->inputstate & INS_DLE_char)) {
 379                                                 inbuf->inputstate |= INS_DLE_char;
 380                                                 goto nextbyte;
 381                                         }
 382                                         /* <DLE> <DLE> => <DLE> in data stream */
 383                                         inbuf->inputstate &= ~INS_DLE_char;
 384                                 }
 385
 386                                 if (!(inbuf->inputstate & INS_DLE_char)) {
 387
 388                                         /* FIXME use function pointers?  */
 389                                         if (inbuf->inputstate & INS_command)
 390                                                 procbytes = cmd_loop(c, src, numbytes, inbuf);
 391                                         else if (inbuf->bcs->proto2 == ISDN_PROTO_L2_HDLC)
 392                                                 procbytes = hdlc_loop(c, src, numbytes, inbuf);
 393                                         else
 394                                                 procbytes = iraw_loop(c, src, numbytes, inbuf);
 395
 396                                         src += procbytes;
 397                                         numbytes -= procbytes;
 398                                 } else {  /* DLE char */
 399                                         inbuf->inputstate &= ~INS_DLE_char;
 400                                         switch (c) {
 401                                         case 'X': /*begin of command*/
 402 #ifdef CONFIG_GIGASET_DEBUG
 403                                                 if (inbuf->inputstate & INS_command)
 404                                                         dev_err(cs->dev,
 405                                         "received <DLE> 'X' in command mode\n");
 406 #endif
 407                                                 inbuf->inputstate |=
 408                                                         INS_command | INS_DLE_command;
 409                                                 break;
 410                                         case '.': /*end of command*/
 411 #ifdef CONFIG_GIGASET_DEBUG
 412                                                 if (!(inbuf->inputstate & INS_command))
 413                                                         dev_err(cs->dev,
 414                                         "received <DLE> '.' in hdlc mode\n");
 415 #endif
 416                                                 inbuf->inputstate &= cs->dle ?
 417                                                         ~(INS_DLE_command|INS_command)
 418                                                         : ~INS_DLE_command;
 419                                                 break;
 420                                         //case DLE_FLAG: /*DLE_FLAG in data stream*/ /* schon oben behandelt! */
 421                                         default:
 422                                                 dev_err(cs->dev,
 423                                                       "received 0x10 0x%02x!\n",
 424                                                         (int) c);
 425                                                 /* FIXME: reset driver?? */
 426                                         }
 427                                 }
 428                         }
 429 nextbyte:
 430                         if (!numbytes) {
 431                                 /* end of buffer, check for wrap */
 432                                 if (head > tail) {
 433                                         head = 0;
 434                                         src = inbuf->data;
 435                                         numbytes = tail;
 436                                 } else {
 437                                         head = tail;
 438                                         break;
 439                                 }
 440                         }
 441                 }
 442
 443                 gig_dbg(DEBUG_INTR, "setting head to %u", head);
 444                 atomic_set(&inbuf->head, head);
 445         }
 446 }
 447
 448
 449 /* == data output ========================================================== */
 450
 451 /* Encoding of a PPP packet into an octet stuffed HDLC frame
 452  * with FCS, opening and closing flags.
 453  * parameters:
 454  *      skb     skb containing original packet (freed upon return)
 455  *      head    number of headroom bytes to allocate in result skb
 456  *      tail    number of tailroom bytes to allocate in result skb
 457  * Return value:
 458  *      pointer to newly allocated skb containing the result frame
 459  */
 460 static struct sk_buff *HDLC_Encode(struct sk_buff *skb, int head, int tail)
 461 {
 462         struct sk_buff *hdlc_skb;
 463         __u16 fcs;
 464         unsigned char c;
 465         unsigned char *cp;
 466         int len;
 467         unsigned int stuf_cnt;
 468
 469         stuf_cnt = 0;
 470         fcs = PPP_INITFCS;
 471         cp = skb->data;
 472         len = skb->len;
 473         while (len--) {
 474                 if (muststuff(*cp))
 475                         stuf_cnt++;
 476                 fcs = crc_ccitt_byte(fcs, *cp++);
 477         }
 478         fcs ^= 0xffff;                  /* complement */
 479
 480         /* size of new buffer: original size + number of stuffing bytes
 481          * + 2 bytes FCS + 2 stuffing bytes for FCS (if needed) + 2 flag bytes
 482          */
 483         hdlc_skb = dev_alloc_skb(skb->len + stuf_cnt + 6 + tail + head);
 484         if (!hdlc_skb) {
 485                 dev_kfree_skb(skb);
 486                 return NULL;
 487         }
 488         skb_reserve(hdlc_skb, head);
 489
 490         /* Copy acknowledge request into new skb */
 491         memcpy(hdlc_skb->head, skb->head, 2);
 492
 493         /* Add flag sequence in front of everything.. */
 494         *(skb_put(hdlc_skb, 1)) = PPP_FLAG;
 495
 496         /* Perform byte stuffing while copying data. */
 497         while (skb->len--) {
 498                 if (muststuff(*skb->data)) {
 499                         *(skb_put(hdlc_skb, 1)) = PPP_ESCAPE;
 500                         *(skb_put(hdlc_skb, 1)) = (*skb->data++) ^ PPP_TRANS;
 501                 } else
 502                         *(skb_put(hdlc_skb, 1)) = *skb->data++;
 503         }
 504
 505         /* Finally add FCS (byte stuffed) and flag sequence */
 506         c = (fcs & 0x00ff);     /* least significant byte first */
 507         if (muststuff(c)) {
 508                 *(skb_put(hdlc_skb, 1)) = PPP_ESCAPE;
 509                 c ^= PPP_TRANS;
 510         }
 511         *(skb_put(hdlc_skb, 1)) = c;
 512
 513         c = ((fcs >> 8) & 0x00ff);
 514         if (muststuff(c)) {
 515                 *(skb_put(hdlc_skb, 1)) = PPP_ESCAPE;
 516                 c ^= PPP_TRANS;
 517         }
 518         *(skb_put(hdlc_skb, 1)) = c;
 519
 520         *(skb_put(hdlc_skb, 1)) = PPP_FLAG;
 521
 522         dev_kfree_skb(skb);
 523         return hdlc_skb;
 524 }
 525
 526 /* Encoding of a raw packet into an octet stuffed bit inverted frame
 527  * parameters:
 528  *      skb     skb containing original packet (freed upon return)
 529  *      head    number of headroom bytes to allocate in result skb
 530  *      tail    number of tailroom bytes to allocate in result skb
 531  * Return value:
 532  *      pointer to newly allocated skb containing the result frame
 533  */
 534 static struct sk_buff *iraw_encode(struct sk_buff *skb, int head, int tail)
 535 {
 536         struct sk_buff *iraw_skb;
 537         unsigned char c;
 538         unsigned char *cp;
 539         int len;
 540
 541         /* worst case: every byte must be stuffed */
 542         iraw_skb = dev_alloc_skb(2*skb->len + tail + head);
 543         if (!iraw_skb) {
 544                 dev_kfree_skb(skb);
 545                 return NULL;
 546         }
 547         skb_reserve(iraw_skb, head);
 548
 549         cp = skb->data;
 550         len = skb->len;
 551         while (len--) {
 552                 c = bitrev8(*cp++);
 553                 if (c == DLE_FLAG)
 554                         *(skb_put(iraw_skb, 1)) = c;
 555                 *(skb_put(iraw_skb, 1)) = c;
 556         }
 557         dev_kfree_skb(skb);
 558         return iraw_skb;
 559 }
 560
 561 /* gigaset_send_skb
 562  * called by common.c to queue an skb for sending
 563  * and start transmission if necessary
 564  * parameters:
 565  *      B Channel control structure
 566  *      skb
 567  * Return value:
 568  *      number of bytes accepted for sending
 569  *      (skb->len if ok, 0 if out of buffer space)
 570  *      or error code (< 0, eg. -EINVAL)
 571  */
 572 int gigaset_m10x_send_skb(struct bc_state *bcs, struct sk_buff *skb)
 573 {
 574         unsigned len = skb->len;
 575         unsigned long flags;
 576
 577         if (bcs->proto2 == ISDN_PROTO_L2_HDLC)
 578                 skb = HDLC_Encode(skb, HW_HDR_LEN, 0);
 579         else
 580                 skb = iraw_encode(skb, HW_HDR_LEN, 0);
 581         if (!skb) {
 582                 err("unable to allocate memory for encoding!\n");
 583                 return -ENOMEM;
 584         }
 585
 586         skb_queue_tail(&bcs->squeue, skb);
 587         spin_lock_irqsave(&bcs->cs->lock, flags);
 588         if (bcs->cs->connected)
 589                 tasklet_schedule(&bcs->cs->write_tasklet);
 590         spin_unlock_irqrestore(&bcs->cs->lock, flags);
 591
 592         return len;     /* ok so far */
 593 }