drivers/misc/ti-st/st_core.c

   1 /*
   2  *  Shared Transport Line discipline driver Core
   3  *      This hooks up ST KIM driver and ST LL driver
   4  *  Copyright (C) 2009-2010 Texas Instruments
   5  *  Author: Pavan Savoy <pavan_savoy@ti.com>
   6  *
   7  *  This program is free software; you can redistribute it and/or modify
   8  *  it under the terms of the GNU General Public License version 2 as
   9  *  published by the Free Software Foundation.
  10  *
  11  *  This program is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *  GNU General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU General Public License
  17  *  along with this program; if not, write to the Free Software
  18  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19  *
  20  */
  21
  22 #define pr_fmt(fmt)     "(stc): " fmt
  23 #include <linux/module.h>
  24 #include <linux/kernel.h>
  25 #include <linux/init.h>
  26 #include <linux/tty.h>
  27
  28 #include <linux/seq_file.h>
  29 #include <linux/skbuff.h>
  30
  31 #include <linux/ti_wilink_st.h>
  32
  33 /* function pointer pointing to either,
  34  * st_kim_recv during registration to receive fw download responses
  35  * st_int_recv after registration to receive proto stack responses
  36  */
  37 void (*st_recv) (void*, const unsigned char*, long);
  38
  39 /********************************************************************/
  40 static void add_channel_to_table(struct st_data_s *st_gdata,
  41                 struct st_proto_s *new_proto)
  42 {
  43         pr_info("%s: id %d\n", __func__, new_proto->chnl_id);
  44         /* list now has the channel id as index itself */
  45         st_gdata->list[new_proto->chnl_id] = new_proto;
  46 }
  47
  48 static void remove_channel_from_table(struct st_data_s *st_gdata,
  49                 struct st_proto_s *proto)
  50 {
  51         pr_info("%s: id %d\n", __func__, proto->chnl_id);
  52         st_gdata->list[proto->chnl_id] = NULL;
  53 }
  54
  55 /*
  56  * called from KIM during firmware download.
  57  *
  58  * This is a wrapper function to tty->ops->write_room.
  59  * It returns number of free space available in
  60  * uart tx buffer.
  61  */
  62 int st_get_uart_wr_room(struct st_data_s *st_gdata)
  63 {
  64         struct tty_struct *tty;
  65         if (unlikely(st_gdata == NULL || st_gdata->tty == NULL)) {
  66                 pr_err("tty unavailable to perform write");
  67                 return -1;
  68         }
  69         tty = st_gdata->tty;
  70         return tty->ops->write_room(tty);
  71 }
  72
  73 /* can be called in from
  74  * -- KIM (during fw download)
  75  * -- ST Core (during st_write)
  76  *
  77  *  This is the internal write function - a wrapper
  78  *  to tty->ops->write
  79  */
  80 int st_int_write(struct st_data_s *st_gdata,
  81         const unsigned char *data, int count)
  82 {
  83         struct tty_struct *tty;
  84         if (unlikely(st_gdata == NULL || st_gdata->tty == NULL)) {
  85                 pr_err("tty unavailable to perform write");
  86                 return -EINVAL;
  87         }
  88         tty = st_gdata->tty;
  89 #ifdef VERBOSE
  90         print_hex_dump(KERN_DEBUG, "<out<", DUMP_PREFIX_NONE,
  91                 16, 1, data, count, 0);
  92 #endif
  93         return tty->ops->write(tty, data, count);
  94
  95 }
  96
  97 /*
  98  * push the skb received to relevant
  99  * protocol stacks
 100  */
 101 void st_send_frame(unsigned char chnl_id, struct st_data_s *st_gdata)
 102 {
 103         pr_debug(" %s(prot:%d) ", __func__, chnl_id);
 104
 105         if (unlikely
 106             (st_gdata == NULL || st_gdata->rx_skb == NULL
 107              || st_gdata->list[chnl_id] == NULL)) {
 108                 pr_err("chnl_id %d not registered, no data to send?",
 109                            chnl_id);
 110                 kfree_skb(st_gdata->rx_skb);
 111                 return;
 112         }
 113         /* this cannot fail
 114          * this shouldn't take long
 115          * - should be just skb_queue_tail for the
 116          *   protocol stack driver
 117          */
 118         if (likely(st_gdata->list[chnl_id]->recv != NULL)) {
 119                 if (unlikely
 120                         (st_gdata->list[chnl_id]->recv
 121                         (st_gdata->list[chnl_id]->priv_data, st_gdata->rx_skb)
 122                              != 0)) {
 123                         pr_err(" proto stack %d's ->recv failed", chnl_id);
 124                         kfree_skb(st_gdata->rx_skb);
 125                         return;
 126                 }
 127         } else {
 128                 pr_err(" proto stack %d's ->recv null", chnl_id);
 129                 kfree_skb(st_gdata->rx_skb);
 130         }
 131         return;
 132 }
 133
 134 /**
 135  * st_reg_complete -
 136  * to call registration complete callbacks
 137  * of all protocol stack drivers
 138  */
 139 void st_reg_complete(struct st_data_s *st_gdata, char err)
 140 {
 141         unsigned char i = 0;
 142         pr_info(" %s ", __func__);
 143         for (i = 0; i < ST_MAX_CHANNELS; i++) {
 144                 if (likely(st_gdata != NULL && st_gdata->list[i] != NULL &&
 145                            st_gdata->list[i]->reg_complete_cb != NULL)) {
 146                         st_gdata->list[i]->reg_complete_cb
 147                                 (st_gdata->list[i]->priv_data, err);
 148                         pr_info("protocol %d's cb sent %d\n", i, err);
 149                         if (err) { /* cleanup registered protocol */
 150                                 st_gdata->protos_registered--;
 151                                 st_gdata->list[i] = NULL;
 152                         }
 153                 }
 154         }
 155 }
 156
 157 static inline int st_check_data_len(struct st_data_s *st_gdata,
 158         unsigned char chnl_id, int len)
 159 {
 160         int room = skb_tailroom(st_gdata->rx_skb);
 161
 162         pr_debug("len %d room %d", len, room);
 163
 164         if (!len) {
 165                 /* Received packet has only packet header and
 166                  * has zero length payload. So, ask ST CORE to
 167                  * forward the packet to protocol driver (BT/FM/GPS)
 168                  */
 169                 st_send_frame(chnl_id, st_gdata);
 170
 171         } else if (len > room) {
 172                 /* Received packet's payload length is larger.
 173                  * We can't accommodate it in created skb.
 174                  */
 175                 pr_err("Data length is too large len %d room %d", len,
 176                            room);
 177                 kfree_skb(st_gdata->rx_skb);
 178         } else {
 179                 /* Packet header has non-zero payload length and
 180                  * we have enough space in created skb. Lets read
 181                  * payload data */
 182                 st_gdata->rx_state = ST_W4_DATA;
 183                 st_gdata->rx_count = len;
 184                 return len;
 185         }
 186
 187         /* Change ST state to continue to process next
 188          * packet */
 189         st_gdata->rx_state = ST_W4_PACKET_TYPE;
 190         st_gdata->rx_skb = NULL;
 191         st_gdata->rx_count = 0;
 192         st_gdata->rx_chnl = 0;
 193
 194         return 0;
 195 }
 196
 197 /**
 198  * st_wakeup_ack - internal function for action when wake-up ack
 199  *      received
 200  */
 201 static inline void st_wakeup_ack(struct st_data_s *st_gdata,
 202         unsigned char cmd)
 203 {
 204         struct sk_buff *waiting_skb;
 205         unsigned long flags = 0;
 206
 207         spin_lock_irqsave(&st_gdata->lock, flags);
 208         /* de-Q from waitQ and Q in txQ now that the
 209          * chip is awake
 210          */
 211         while ((waiting_skb = skb_dequeue(&st_gdata->tx_waitq)))
 212                 skb_queue_tail(&st_gdata->txq, waiting_skb);
 213
 214         /* state forwarded to ST LL */
 215         st_ll_sleep_state(st_gdata, (unsigned long)cmd);
 216         spin_unlock_irqrestore(&st_gdata->lock, flags);
 217
 218         /* wake up to send the recently copied skbs from waitQ */
 219         st_tx_wakeup(st_gdata);
 220 }
 221
 222 /**
 223  * st_int_recv - ST's internal receive function.
 224  *      Decodes received RAW data and forwards to corresponding
 225  *      client drivers (Bluetooth,FM,GPS..etc).
 226  *      This can receive various types of packets,
 227  *      HCI-Events, ACL, SCO, 4 types of HCI-LL PM packets
 228  *      CH-8 packets from FM, CH-9 packets from GPS cores.
 229  */
 230 void st_int_recv(void *disc_data,
 231         const unsigned char *data, long count)
 232 {
 233         char *ptr;
 234         struct st_proto_s *proto;
 235         unsigned short payload_len = 0;
 236         int len = 0, type = 0;
 237         unsigned char *plen;
 238         struct st_data_s *st_gdata = (struct st_data_s *)disc_data;
 239         unsigned long flags;
 240
 241         ptr = (char *)data;
 242         /* tty_receive sent null ? */
 243         if (unlikely(ptr == NULL) || (st_gdata == NULL)) {
 244                 pr_err(" received null from TTY ");
 245                 return;
 246         }
 247
 248         pr_debug("count %ld rx_state %ld"
 249                    "rx_count %ld", count, st_gdata->rx_state,
 250                    st_gdata->rx_count);
 251
 252         spin_lock_irqsave(&st_gdata->lock, flags);
 253         /* Decode received bytes here */
 254         while (count) {
 255                 if (st_gdata->rx_count) {
 256                         len = min_t(unsigned int, st_gdata->rx_count, count);
 257                         memcpy(skb_put(st_gdata->rx_skb, len), ptr, len);
 258                         st_gdata->rx_count -= len;
 259                         count -= len;
 260                         ptr += len;
 261
 262                         if (st_gdata->rx_count)
 263                                 continue;
 264
 265                         /* Check ST RX state machine , where are we? */
 266                         switch (st_gdata->rx_state) {
 267                         /* Waiting for complete packet ? */
 268                         case ST_W4_DATA:
 269                                 pr_debug("Complete pkt received");
 270                                 /* Ask ST CORE to forward
 271                                  * the packet to protocol driver */
 272                                 st_send_frame(st_gdata->rx_chnl, st_gdata);
 273
 274                                 st_gdata->rx_state = ST_W4_PACKET_TYPE;
 275                                 st_gdata->rx_skb = NULL;
 276                                 continue;
 277                         /* parse the header to know details */
 278                         case ST_W4_HEADER:
 279                                 proto = st_gdata->list[st_gdata->rx_chnl];
 280                                 plen =
 281                                 &st_gdata->rx_skb->data
 282                                 [proto->offset_len_in_hdr];
 283                                 pr_debug("plen pointing to %x\n", *plen);
 284                                 if (proto->len_size == 1)/* 1 byte len field */
 285                                         payload_len = *(unsigned char *)plen;
 286                                 else if (proto->len_size == 2)
 287                                         payload_len =
 288                                         __le16_to_cpu(*(unsigned short *)plen);
 289                                 else
 290                                         pr_info("%s: invalid length "
 291                                         "for id %d\n",
 292                                         __func__, proto->chnl_id);
 293                                 st_check_data_len(st_gdata, proto->chnl_id,
 294                                                 payload_len);
 295                                 pr_debug("off %d, pay len %d\n",
 296                                         proto->offset_len_in_hdr, payload_len);
 297                                 continue;
 298                         }       /* end of switch rx_state */
 299                 }
 300
 301                 /* end of if rx_count */
 302                 /* Check first byte of packet and identify module
 303                  * owner (BT/FM/GPS) */
 304                 switch (*ptr) {
 305                 case LL_SLEEP_IND:
 306                 case LL_SLEEP_ACK:
 307                 case LL_WAKE_UP_IND:
 308                         pr_debug("PM packet");
 309                         /* this takes appropriate action based on
 310                          * sleep state received --
 311                          */
 312                         st_ll_sleep_state(st_gdata, *ptr);
 313                         /* if WAKEUP_IND collides copy from waitq to txq
 314                          * and assume chip awake
 315                          */
 316                         spin_unlock_irqrestore(&st_gdata->lock, flags);
 317                         if (st_ll_getstate(st_gdata) == ST_LL_AWAKE)
 318                                 st_wakeup_ack(st_gdata, LL_WAKE_UP_ACK);
 319                         spin_lock_irqsave(&st_gdata->lock, flags);
 320
 321                         ptr++;
 322                         count--;
 323                         continue;
 324                 case LL_WAKE_UP_ACK:
 325                         pr_debug("PM packet");
 326
 327                         spin_unlock_irqrestore(&st_gdata->lock, flags);
 328                         /* wake up ack received */
 329                         st_wakeup_ack(st_gdata, *ptr);
 330                         spin_lock_irqsave(&st_gdata->lock, flags);
 331
 332                         ptr++;
 333                         count--;
 334                         continue;
 335                         /* Unknow packet? */
 336                 default:
 337                         type = *ptr;
 338                         st_gdata->rx_skb = alloc_skb(
 339                                         st_gdata->list[type]->max_frame_size,
 340                                         GFP_ATOMIC);
 341                         skb_reserve(st_gdata->rx_skb,
 342                                         st_gdata->list[type]->reserve);
 343                         /* next 2 required for BT only */
 344                         st_gdata->rx_skb->cb[0] = type; /*pkt_type*/
 345                         st_gdata->rx_skb->cb[1] = 0; /*incoming*/
 346                         st_gdata->rx_chnl = *ptr;
 347                         st_gdata->rx_state = ST_W4_HEADER;
 348                         st_gdata->rx_count = st_gdata->list[type]->hdr_len;
 349                         pr_debug("rx_count %ld\n", st_gdata->rx_count);
 350                 };
 351                 ptr++;
 352                 count--;
 353         }
 354         spin_unlock_irqrestore(&st_gdata->lock, flags);
 355         pr_debug("done %s", __func__);
 356         return;
 357 }
 358
 359 /**
 360  * st_int_dequeue - internal de-Q function.
 361  *      If the previous data set was not written
 362  *      completely, return that skb which has the pending data.
 363  *      In normal cases, return top of txq.
 364  */
 365 struct sk_buff *st_int_dequeue(struct st_data_s *st_gdata)
 366 {
 367         struct sk_buff *returning_skb;
 368
 369         pr_debug("%s", __func__);
 370         if (st_gdata->tx_skb != NULL) {
 371                 returning_skb = st_gdata->tx_skb;
 372                 st_gdata->tx_skb = NULL;
 373                 return returning_skb;
 374         }
 375         return skb_dequeue(&st_gdata->txq);
 376 }
 377
 378 /**
 379  * st_int_enqueue - internal Q-ing function.
 380  *      Will either Q the skb to txq or the tx_waitq
 381  *      depending on the ST LL state.
 382  *      If the chip is asleep, then Q it onto waitq and
 383  *      wakeup the chip.
 384  *      txq and waitq needs protection since the other contexts
 385  *      may be sending data, waking up chip.
 386  */
 387 void st_int_enqueue(struct st_data_s *st_gdata, struct sk_buff *skb)
 388 {
 389         unsigned long flags = 0;
 390
 391         pr_debug("%s", __func__);
 392         spin_lock_irqsave(&st_gdata->lock, flags);
 393
 394         switch (st_ll_getstate(st_gdata)) {
 395         case ST_LL_AWAKE:
 396                 pr_debug("ST LL is AWAKE, sending normally");
 397                 skb_queue_tail(&st_gdata->txq, skb);
 398                 break;
 399         case ST_LL_ASLEEP_TO_AWAKE:
 400                 skb_queue_tail(&st_gdata->tx_waitq, skb);
 401                 break;
 402         case ST_LL_AWAKE_TO_ASLEEP:
 403                 pr_err("ST LL is illegal state(%ld),"
 404                            "purging received skb.", st_ll_getstate(st_gdata));
 405                 kfree_skb(skb);
 406                 break;
 407         case ST_LL_ASLEEP:
 408                 skb_queue_tail(&st_gdata->tx_waitq, skb);
 409                 st_ll_wakeup(st_gdata);
 410                 break;
 411         default:
 412                 pr_err("ST LL is illegal state(%ld),"
 413                            "purging received skb.", st_ll_getstate(st_gdata));
 414                 kfree_skb(skb);
 415                 break;
 416         }
 417
 418         spin_unlock_irqrestore(&st_gdata->lock, flags);
 419         pr_debug("done %s", __func__);
 420         return;
 421 }
 422
 423 /*
 424  * internal wakeup function
 425  * called from either
 426  * - TTY layer when write's finished
 427  * - st_write (in context of the protocol stack)
 428  */
 429 void st_tx_wakeup(struct st_data_s *st_data)
 430 {
 431         struct sk_buff *skb;
 432         unsigned long flags;    /* for irq save flags */
 433         pr_debug("%s", __func__);
 434         /* check for sending & set flag sending here */
 435         if (test_and_set_bit(ST_TX_SENDING, &st_data->tx_state)) {
 436                 pr_debug("ST already sending");
 437                 /* keep sending */
 438                 set_bit(ST_TX_WAKEUP, &st_data->tx_state);
 439                 return;
 440                 /* TX_WAKEUP will be checked in another
 441                  * context
 442                  */
 443         }
 444         do {                    /* come back if st_tx_wakeup is set */
 445                 /* woke-up to write */
 446                 clear_bit(ST_TX_WAKEUP, &st_data->tx_state);
 447                 while ((skb = st_int_dequeue(st_data))) {
 448                         int len;
 449                         spin_lock_irqsave(&st_data->lock, flags);
 450                         /* enable wake-up from TTY */
 451                         set_bit(TTY_DO_WRITE_WAKEUP, &st_data->tty->flags);
 452                         len = st_int_write(st_data, skb->data, skb->len);
 453                         skb_pull(skb, len);
 454                         /* if skb->len = len as expected, skb->len=0 */
 455                         if (skb->len) {
 456                                 /* would be the next skb to be sent */
 457                                 st_data->tx_skb = skb;
 458                                 spin_unlock_irqrestore(&st_data->lock, flags);
 459                                 break;
 460                         }
 461                         kfree_skb(skb);
 462                         spin_unlock_irqrestore(&st_data->lock, flags);
 463                 }
 464                 /* if wake-up is set in another context- restart sending */
 465         } while (test_bit(ST_TX_WAKEUP, &st_data->tx_state));
 466
 467         /* clear flag sending */
 468         clear_bit(ST_TX_SENDING, &st_data->tx_state);
 469 }
 470
 471 /********************************************************************/
 472 /* functions called from ST KIM
 473 */
 474 void kim_st_list_protocols(struct st_data_s *st_gdata, void *buf)
 475 {
 476         seq_printf(buf, "[%d]\nBT=%c\nFM=%c\nGPS=%c\n",
 477                         st_gdata->protos_registered,
 478                         st_gdata->list[ST_BT] != NULL ? 'R' : 'U',
 479                         st_gdata->list[ST_FM] != NULL ? 'R' : 'U',
 480                         st_gdata->list[ST_GPS] != NULL ? 'R' : 'U');
 481 }
 482
 483 /********************************************************************/
 484 /*
 485  * functions called from protocol stack drivers
 486  * to be EXPORT-ed
 487  */
 488 long st_register(struct st_proto_s *new_proto)
 489 {
 490         struct st_data_s        *st_gdata;
 491         long err = 0;
 492         unsigned long flags = 0;
 493
 494         st_kim_ref(&st_gdata, 0);
 495         pr_info("%s(%d) ", __func__, new_proto->chnl_id);
 496         if (st_gdata == NULL || new_proto == NULL || new_proto->recv == NULL
 497             || new_proto->reg_complete_cb == NULL) {
 498                 pr_err("gdata/new_proto/recv or reg_complete_cb not ready");
 499                 return -EINVAL;
 500         }
 501
 502         if (new_proto->chnl_id >= ST_MAX_CHANNELS) {
 503                 pr_err("chnl_id %d not supported", new_proto->chnl_id);
 504                 return -EPROTONOSUPPORT;
 505         }
 506
 507         if (st_gdata->list[new_proto->chnl_id] != NULL) {
 508                 pr_err("chnl_id %d already registered", new_proto->chnl_id);
 509                 return -EALREADY;
 510         }
 511
 512         /* can be from process context only */
 513         spin_lock_irqsave(&st_gdata->lock, flags);
 514
 515         if (test_bit(ST_REG_IN_PROGRESS, &st_gdata->st_state)) {
 516                 pr_info(" ST_REG_IN_PROGRESS:%d ", new_proto->chnl_id);
 517                 /* fw download in progress */
 518
 519                 add_channel_to_table(st_gdata, new_proto);
 520                 st_gdata->protos_registered++;
 521                 new_proto->write = st_write;
 522
 523                 set_bit(ST_REG_PENDING, &st_gdata->st_state);
 524                 spin_unlock_irqrestore(&st_gdata->lock, flags);
 525                 return -EINPROGRESS;
 526         } else if (st_gdata->protos_registered == ST_EMPTY) {
 527                 pr_info(" chnl_id list empty :%d ", new_proto->chnl_id);
 528                 set_bit(ST_REG_IN_PROGRESS, &st_gdata->st_state);
 529                 st_recv = st_kim_recv;
 530
 531                 /* release lock previously held - re-locked below */
 532                 spin_unlock_irqrestore(&st_gdata->lock, flags);
 533
 534                 /* enable the ST LL - to set default chip state */
 535                 st_ll_enable(st_gdata);
 536                 /* this may take a while to complete
 537                  * since it involves BT fw download
 538                  */
 539                 err = st_kim_start(st_gdata->kim_data);
 540                 if (err != 0) {
 541                         clear_bit(ST_REG_IN_PROGRESS, &st_gdata->st_state);
 542                         if ((st_gdata->protos_registered != ST_EMPTY) &&
 543                             (test_bit(ST_REG_PENDING, &st_gdata->st_state))) {
 544                                 pr_err(" KIM failure complete callback ");
 545                                 st_reg_complete(st_gdata, err);
 546                         }
 547                         return -EINVAL;
 548                 }
 549
 550                 clear_bit(ST_REG_IN_PROGRESS, &st_gdata->st_state);
 551                 st_recv = st_int_recv;
 552
 553                 /* this is where all pending registration
 554                  * are signalled to be complete by calling callback functions
 555                  */
 556                 if ((st_gdata->protos_registered != ST_EMPTY) &&
 557                     (test_bit(ST_REG_PENDING, &st_gdata->st_state))) {
 558                         pr_debug(" call reg complete callback ");
 559                         st_reg_complete(st_gdata, 0);
 560                 }
 561                 clear_bit(ST_REG_PENDING, &st_gdata->st_state);
 562
 563                 /* check for already registered once more,
 564                  * since the above check is old
 565                  */
 566                 if (st_gdata->list[new_proto->chnl_id] != NULL) {
 567                         pr_err(" proto %d already registered ",
 568                                    new_proto->chnl_id);
 569                         return -EALREADY;
 570                 }
 571
 572                 spin_lock_irqsave(&st_gdata->lock, flags);
 573                 add_channel_to_table(st_gdata, new_proto);
 574                 st_gdata->protos_registered++;
 575                 new_proto->write = st_write;
 576                 spin_unlock_irqrestore(&st_gdata->lock, flags);
 577                 return err;
 578         }
 579         /* if fw is already downloaded & new stack registers protocol */
 580         else {
 581                 add_channel_to_table(st_gdata, new_proto);
 582                 st_gdata->protos_registered++;
 583                 new_proto->write = st_write;
 584
 585                 /* lock already held before entering else */
 586                 spin_unlock_irqrestore(&st_gdata->lock, flags);
 587                 return err;
 588         }
 589         pr_debug("done %s(%d) ", __func__, new_proto->chnl_id);
 590 }
 591 EXPORT_SYMBOL_GPL(st_register);
 592
 593 /* to unregister a protocol -
 594  * to be called from protocol stack driver
 595  */
 596 long st_unregister(struct st_proto_s *proto)
 597 {
 598         long err = 0;
 599         unsigned long flags = 0;
 600         struct st_data_s        *st_gdata;
 601
 602         pr_debug("%s: %d ", __func__, proto->chnl_id);
 603
 604         st_kim_ref(&st_gdata, 0);
 605         if (proto->chnl_id >= ST_MAX_CHANNELS) {
 606                 pr_err(" chnl_id %d not supported", proto->chnl_id);
 607                 return -EPROTONOSUPPORT;
 608         }
 609
 610         spin_lock_irqsave(&st_gdata->lock, flags);
 611
 612         if (st_gdata->list[proto->chnl_id] == NULL) {
 613                 pr_err(" chnl_id %d not registered", proto->chnl_id);
 614                 spin_unlock_irqrestore(&st_gdata->lock, flags);
 615                 return -EPROTONOSUPPORT;
 616         }
 617
 618         st_gdata->protos_registered--;
 619         remove_channel_from_table(st_gdata, proto);
 620         spin_unlock_irqrestore(&st_gdata->lock, flags);
 621
 622         if ((st_gdata->protos_registered == ST_EMPTY) &&
 623             (!test_bit(ST_REG_PENDING, &st_gdata->st_state))) {
 624                 pr_info(" all chnl_ids unregistered ");
 625
 626                 /* stop traffic on tty */
 627                 if (st_gdata->tty) {
 628                         tty_ldisc_flush(st_gdata->tty);
 629                         stop_tty(st_gdata->tty);
 630                 }
 631
 632                 /* all chnl_ids now unregistered */
 633                 st_kim_stop(st_gdata->kim_data);
 634                 /* disable ST LL */
 635                 st_ll_disable(st_gdata);
 636         }
 637         return err;
 638 }
 639
 640 /*
 641  * called in protocol stack drivers
 642  * via the write function pointer
 643  */
 644 long st_write(struct sk_buff *skb)
 645 {
 646         struct st_data_s *st_gdata;
 647 #ifdef DEBUG
 648         unsigned char chnl_id = ST_MAX_CHANNELS;
 649 #endif
 650         long len;
 651
 652         st_kim_ref(&st_gdata, 0);
 653         if (unlikely(skb == NULL || st_gdata == NULL
 654                 || st_gdata->tty == NULL)) {
 655                 pr_err("data/tty unavailable to perform write");
 656                 return -EINVAL;
 657         }
 658 #ifdef DEBUG                    /* open-up skb to read the 1st byte */
 659         chnl_id = skb->data[0];
 660         if (unlikely(st_gdata->list[chnl_id] == NULL)) {
 661                 pr_err(" chnl_id %d not registered, and writing? ",
 662                            chnl_id);
 663                 return -EINVAL;
 664         }
 665 #endif
 666         pr_debug("%d to be written", skb->len);
 667         len = skb->len;
 668
 669         /* st_ll to decide where to enqueue the skb */
 670         st_int_enqueue(st_gdata, skb);
 671         /* wake up */
 672         st_tx_wakeup(st_gdata);
 673
 674         /* return number of bytes written */
 675         return len;
 676 }
 677
 678 /* for protocols making use of shared transport */
 679 EXPORT_SYMBOL_GPL(st_unregister);
 680
 681 /********************************************************************/
 682 /*
 683  * functions called from TTY layer
 684  */
 685 static int st_tty_open(struct tty_struct *tty)
 686 {
 687         int err = 0;
 688         struct st_data_s *st_gdata;
 689         pr_info("%s ", __func__);
 690
 691         st_kim_ref(&st_gdata, 0);
 692         st_gdata->tty = tty;
 693         tty->disc_data = st_gdata;
 694
 695         /* don't do an wakeup for now */
 696         clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
 697
 698         /* mem already allocated
 699          */
 700         tty->receive_room = 65536;
 701         /* Flush any pending characters in the driver and discipline. */
 702         tty_ldisc_flush(tty);
 703         tty_driver_flush_buffer(tty);
 704         /*
 705          * signal to UIM via KIM that -
 706          * installation of N_TI_WL ldisc is complete
 707          */
 708         st_kim_complete(st_gdata->kim_data);
 709         pr_debug("done %s", __func__);
 710         return err;
 711 }
 712
 713 static void st_tty_close(struct tty_struct *tty)
 714 {
 715         unsigned char i = ST_MAX_CHANNELS;
 716         unsigned long flags = 0;
 717         struct  st_data_s *st_gdata = tty->disc_data;
 718
 719         pr_info("%s ", __func__);
 720
 721         /* TODO:
 722          * if a protocol has been registered & line discipline
 723          * un-installed for some reason - what should be done ?
 724          */
 725         spin_lock_irqsave(&st_gdata->lock, flags);
 726         for (i = ST_BT; i < ST_MAX_CHANNELS; i++) {
 727                 if (st_gdata->list[i] != NULL)
 728                         pr_err("%d not un-registered", i);
 729                 st_gdata->list[i] = NULL;
 730         }
 731         st_gdata->protos_registered = 0;
 732         spin_unlock_irqrestore(&st_gdata->lock, flags);
 733         /*
 734          * signal to UIM via KIM that -
 735          * N_TI_WL ldisc is un-installed
 736          */
 737         st_kim_complete(st_gdata->kim_data);
 738         st_gdata->tty = NULL;
 739         /* Flush any pending characters in the driver and discipline. */
 740         tty_ldisc_flush(tty);
 741         tty_driver_flush_buffer(tty);
 742
 743         spin_lock_irqsave(&st_gdata->lock, flags);
 744         /* empty out txq and tx_waitq */
 745         skb_queue_purge(&st_gdata->txq);
 746         skb_queue_purge(&st_gdata->tx_waitq);
 747         /* reset the TTY Rx states of ST */
 748         st_gdata->rx_count = 0;
 749         st_gdata->rx_state = ST_W4_PACKET_TYPE;
 750         kfree_skb(st_gdata->rx_skb);
 751         st_gdata->rx_skb = NULL;
 752         spin_unlock_irqrestore(&st_gdata->lock, flags);
 753
 754         pr_debug("%s: done ", __func__);
 755 }
 756
 757 static void st_tty_receive(struct tty_struct *tty, const unsigned char *data,
 758                            char *tty_flags, int count)
 759 {
 760 #ifdef VERBOSE
 761         print_hex_dump(KERN_DEBUG, ">in>", DUMP_PREFIX_NONE,
 762                 16, 1, data, count, 0);
 763 #endif
 764
 765         /*
 766          * if fw download is in progress then route incoming data
 767          * to KIM for validation
 768          */
 769         st_recv(tty->disc_data, data, count);
 770         pr_debug("done %s", __func__);
 771 }
 772
 773 /* wake-up function called in from the TTY layer
 774  * inside the internal wakeup function will be called
 775  */
 776 static void st_tty_wakeup(struct tty_struct *tty)
 777 {
 778         struct  st_data_s *st_gdata = tty->disc_data;
 779         pr_debug("%s ", __func__);
 780         /* don't do an wakeup for now */
 781         clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
 782
 783         /* call our internal wakeup */
 784         st_tx_wakeup((void *)st_gdata);
 785 }
 786
 787 static void st_tty_flush_buffer(struct tty_struct *tty)
 788 {
 789         struct  st_data_s *st_gdata = tty->disc_data;
 790         pr_debug("%s ", __func__);
 791
 792         kfree_skb(st_gdata->tx_skb);
 793         st_gdata->tx_skb = NULL;
 794
 795         tty->ops->flush_buffer(tty);
 796         return;
 797 }
 798
 799 static struct tty_ldisc_ops st_ldisc_ops = {
 800         .magic = TTY_LDISC_MAGIC,
 801         .name = "n_st",
 802         .open = st_tty_open,
 803         .close = st_tty_close,
 804         .receive_buf = st_tty_receive,
 805         .write_wakeup = st_tty_wakeup,
 806         .flush_buffer = st_tty_flush_buffer,
 807         .owner = THIS_MODULE
 808 };
 809
 810 /********************************************************************/
 811 int st_core_init(struct st_data_s **core_data)
 812 {
 813         struct st_data_s *st_gdata;
 814         long err;
 815
 816         err = tty_register_ldisc(N_TI_WL, &st_ldisc_ops);
 817         if (err) {
 818                 pr_err("error registering %d line discipline %ld",
 819                            N_TI_WL, err);
 820                 return err;
 821         }
 822         pr_debug("registered n_shared line discipline");
 823
 824         st_gdata = kzalloc(sizeof(struct st_data_s), GFP_KERNEL);
 825         if (!st_gdata) {
 826                 pr_err("memory allocation failed");
 827                 err = tty_unregister_ldisc(N_TI_WL);
 828                 if (err)
 829                         pr_err("unable to un-register ldisc %ld", err);
 830                 err = -ENOMEM;
 831                 return err;
 832         }
 833
 834         /* Initialize ST TxQ and Tx waitQ queue head. All BT/FM/GPS module skb's
 835          * will be pushed in this queue for actual transmission.
 836          */
 837         skb_queue_head_init(&st_gdata->txq);
 838         skb_queue_head_init(&st_gdata->tx_waitq);
 839
 840         /* Locking used in st_int_enqueue() to avoid multiple execution */
 841         spin_lock_init(&st_gdata->lock);
 842
 843         err = st_ll_init(st_gdata);
 844         if (err) {
 845                 pr_err("error during st_ll initialization(%ld)", err);
 846                 kfree(st_gdata);
 847                 err = tty_unregister_ldisc(N_TI_WL);
 848                 if (err)
 849                         pr_err("unable to un-register ldisc");
 850                 return err;
 851         }
 852         *core_data = st_gdata;
 853         return 0;
 854 }
 855
 856 void st_core_exit(struct st_data_s *st_gdata)
 857 {
 858         long err;
 859         /* internal module cleanup */
 860         err = st_ll_deinit(st_gdata);
 861         if (err)
 862                 pr_err("error during deinit of ST LL %ld", err);
 863
 864         if (st_gdata != NULL) {
 865                 /* Free ST Tx Qs and skbs */
 866                 skb_queue_purge(&st_gdata->txq);
 867                 skb_queue_purge(&st_gdata->tx_waitq);
 868                 kfree_skb(st_gdata->rx_skb);
 869                 kfree_skb(st_gdata->tx_skb);
 870                 /* TTY ldisc cleanup */
 871                 err = tty_unregister_ldisc(N_TI_WL);
 872                 if (err)
 873                         pr_err("unable to un-register ldisc %ld", err);
 874                 /* free the global data pointer */
 875                 kfree(st_gdata);
 876         }
 877 }
 878
 879