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         st_gdata->is_registered[new_proto->chnl_id] = true;
  47 }
  48
  49 static void remove_channel_from_table(struct st_data_s *st_gdata,
  50                 struct st_proto_s *proto)
  51 {
  52         pr_info("%s: id %d\n", __func__, proto->chnl_id);
  53 /*      st_gdata->list[proto->chnl_id] = NULL; */
  54         st_gdata->is_registered[proto->chnl_id] = false;
  55 }
  56
  57 /*
  58  * called from KIM during firmware download.
  59  *
  60  * This is a wrapper function to tty->ops->write_room.
  61  * It returns number of free space available in
  62  * uart tx buffer.
  63  */
  64 int st_get_uart_wr_room(struct st_data_s *st_gdata)
  65 {
  66         struct tty_struct *tty;
  67         if (unlikely(st_gdata == NULL || st_gdata->tty == NULL)) {
  68                 pr_err("tty unavailable to perform write");
  69                 return -1;
  70         }
  71         tty = st_gdata->tty;
  72         return tty->ops->write_room(tty);
  73 }
  74
  75 /* can be called in from
  76  * -- KIM (during fw download)
  77  * -- ST Core (during st_write)
  78  *
  79  *  This is the internal write function - a wrapper
  80  *  to tty->ops->write
  81  */
  82 int st_int_write(struct st_data_s *st_gdata,
  83         const unsigned char *data, int count)
  84 {
  85         struct tty_struct *tty;
  86         if (unlikely(st_gdata == NULL || st_gdata->tty == NULL)) {
  87                 pr_err("tty unavailable to perform write");
  88                 return -EINVAL;
  89         }
  90         tty = st_gdata->tty;
  91 #ifdef VERBOSE
  92         print_hex_dump(KERN_DEBUG, "<out<", DUMP_PREFIX_NONE,
  93                 16, 1, data, count, 0);
  94 #endif
  95         return tty->ops->write(tty, data, count);
  96
  97 }
  98
  99 /*
 100  * push the skb received to relevant
 101  * protocol stacks
 102  */
 103 void st_send_frame(unsigned char chnl_id, struct st_data_s *st_gdata)
 104 {
 105         pr_debug(" %s(prot:%d) ", __func__, chnl_id);
 106
 107         if (unlikely
 108             (st_gdata == NULL || st_gdata->rx_skb == NULL
 109              || st_gdata->is_registered[chnl_id] == false)) {
 110                 pr_err("chnl_id %d not registered, no data to send?",
 111                            chnl_id);
 112                 kfree_skb(st_gdata->rx_skb);
 113                 return;
 114         }
 115         /* this cannot fail
 116          * this shouldn't take long
 117          * - should be just skb_queue_tail for the
 118          *   protocol stack driver
 119          */
 120         if (likely(st_gdata->list[chnl_id]->recv != NULL)) {
 121                 if (unlikely
 122                         (st_gdata->list[chnl_id]->recv
 123                         (st_gdata->list[chnl_id]->priv_data, st_gdata->rx_skb)
 124                              != 0)) {
 125                         pr_err(" proto stack %d's ->recv failed", chnl_id);
 126                         kfree_skb(st_gdata->rx_skb);
 127                         return;
 128                 }
 129         } else {
 130                 pr_err(" proto stack %d's ->recv null", chnl_id);
 131                 kfree_skb(st_gdata->rx_skb);
 132         }
 133         return;
 134 }
 135
 136 /**
 137  * st_reg_complete -
 138  * to call registration complete callbacks
 139  * of all protocol stack drivers
 140  */
 141 void st_reg_complete(struct st_data_s *st_gdata, char err)
 142 {
 143         unsigned char i = 0;
 144         pr_info(" %s ", __func__);
 145         for (i = 0; i < ST_MAX_CHANNELS; i++) {
 146                 if (likely(st_gdata != NULL &&
 147                         st_gdata->is_registered[i] == true &&
 148                                 st_gdata->list[i]->reg_complete_cb != NULL)) {
 149                         st_gdata->list[i]->reg_complete_cb
 150                                 (st_gdata->list[i]->priv_data, err);
 151                         pr_info("protocol %d's cb sent %d\n", i, err);
 152                         if (err) { /* cleanup registered protocol */
 153                                 st_gdata->protos_registered--;
 154                                 st_gdata->is_registered[i] = false;
 155                         }
 156                 }
 157         }
 158 }
 159
 160 static inline int st_check_data_len(struct st_data_s *st_gdata,
 161         unsigned char chnl_id, int len)
 162 {
 163         int room = skb_tailroom(st_gdata->rx_skb);
 164
 165         pr_debug("len %d room %d", len, room);
 166
 167         if (!len) {
 168                 /* Received packet has only packet header and
 169                  * has zero length payload. So, ask ST CORE to
 170                  * forward the packet to protocol driver (BT/FM/GPS)
 171                  */
 172                 st_send_frame(chnl_id, st_gdata);
 173
 174         } else if (len > room) {
 175                 /* Received packet's payload length is larger.
 176                  * We can't accommodate it in created skb.
 177                  */
 178                 pr_err("Data length is too large len %d room %d", len,
 179                            room);
 180                 kfree_skb(st_gdata->rx_skb);
 181         } else {
 182                 /* Packet header has non-zero payload length and
 183                  * we have enough space in created skb. Lets read
 184                  * payload data */
 185                 st_gdata->rx_state = ST_W4_DATA;
 186                 st_gdata->rx_count = len;
 187                 return len;
 188         }
 189
 190         /* Change ST state to continue to process next
 191          * packet */
 192         st_gdata->rx_state = ST_W4_PACKET_TYPE;
 193         st_gdata->rx_skb = NULL;
 194         st_gdata->rx_count = 0;
 195         st_gdata->rx_chnl = 0;
 196
 197         return 0;
 198 }
 199
 200 /**
 201  * st_wakeup_ack - internal function for action when wake-up ack
 202  *      received
 203  */
 204 static inline void st_wakeup_ack(struct st_data_s *st_gdata,
 205         unsigned char cmd)
 206 {
 207         struct sk_buff *waiting_skb;
 208         unsigned long flags = 0;
 209
 210         spin_lock_irqsave(&st_gdata->lock, flags);
 211         /* de-Q from waitQ and Q in txQ now that the
 212          * chip is awake
 213          */
 214         while ((waiting_skb = skb_dequeue(&st_gdata->tx_waitq)))
 215                 skb_queue_tail(&st_gdata->txq, waiting_skb);
 216
 217         /* state forwarded to ST LL */
 218         st_ll_sleep_state(st_gdata, (unsigned long)cmd);
 219         spin_unlock_irqrestore(&st_gdata->lock, flags);
 220
 221         /* wake up to send the recently copied skbs from waitQ */
 222         st_tx_wakeup(st_gdata);
 223 }
 224
 225 /**
 226  * st_int_recv - ST's internal receive function.
 227  *      Decodes received RAW data and forwards to corresponding
 228  *      client drivers (Bluetooth,FM,GPS..etc).
 229  *      This can receive various types of packets,
 230  *      HCI-Events, ACL, SCO, 4 types of HCI-LL PM packets
 231  *      CH-8 packets from FM, CH-9 packets from GPS cores.
 232  */
 233 void st_int_recv(void *disc_data,
 234         const unsigned char *data, long count)
 235 {
 236         char *ptr;
 237         struct st_proto_s *proto;
 238         unsigned short payload_len = 0;
 239         int len = 0, type = 0;
 240         unsigned char *plen;
 241         struct st_data_s *st_gdata = (struct st_data_s *)disc_data;
 242         unsigned long flags;
 243
 244         ptr = (char *)data;
 245         /* tty_receive sent null ? */
 246         if (unlikely(ptr == NULL) || (st_gdata == NULL)) {
 247                 pr_err(" received null from TTY ");
 248                 return;
 249         }
 250
 251         pr_debug("count %ld rx_state %ld"
 252                    "rx_count %ld", count, st_gdata->rx_state,
 253                    st_gdata->rx_count);
 254
 255         spin_lock_irqsave(&st_gdata->lock, flags);
 256         /* Decode received bytes here */
 257         while (count) {
 258                 if (st_gdata->rx_count) {
 259                         len = min_t(unsigned int, st_gdata->rx_count, count);
 260                         memcpy(skb_put(st_gdata->rx_skb, len), ptr, len);
 261                         st_gdata->rx_count -= len;
 262                         count -= len;
 263                         ptr += len;
 264
 265                         if (st_gdata->rx_count)
 266                                 continue;
 267
 268                         /* Check ST RX state machine , where are we? */
 269                         switch (st_gdata->rx_state) {
 270                         /* Waiting for complete packet ? */
 271                         case ST_W4_DATA:
 272                                 pr_debug("Complete pkt received");
 273                                 /* Ask ST CORE to forward
 274                                  * the packet to protocol driver */
 275                                 st_send_frame(st_gdata->rx_chnl, st_gdata);
 276
 277                                 st_gdata->rx_state = ST_W4_PACKET_TYPE;
 278                                 st_gdata->rx_skb = NULL;
 279                                 continue;
 280                         /* parse the header to know details */
 281                         case ST_W4_HEADER:
 282                                 proto = st_gdata->list[st_gdata->rx_chnl];
 283                                 plen =
 284                                 &st_gdata->rx_skb->data
 285                                 [proto->offset_len_in_hdr];
 286                                 pr_debug("plen pointing to %x\n", *plen);
 287                                 if (proto->len_size == 1)/* 1 byte len field */
 288                                         payload_len = *(unsigned char *)plen;
 289                                 else if (proto->len_size == 2)
 290                                         payload_len =
 291                                         __le16_to_cpu(*(unsigned short *)plen);
 292                                 else
 293                                         pr_info("%s: invalid length "
 294                                         "for id %d\n",
 295                                         __func__, proto->chnl_id);
 296                                 st_check_data_len(st_gdata, proto->chnl_id,
 297                                                 payload_len);
 298                                 pr_debug("off %d, pay len %d\n",
 299                                         proto->offset_len_in_hdr, payload_len);
 300                                 continue;
 301                         }       /* end of switch rx_state */
 302                 }
 303
 304                 /* end of if rx_count */
 305                 /* Check first byte of packet and identify module
 306                  * owner (BT/FM/GPS) */
 307                 switch (*ptr) {
 308                 case LL_SLEEP_IND:
 309                 case LL_SLEEP_ACK:
 310                 case LL_WAKE_UP_IND:
 311                         pr_debug("PM packet");
 312                         /* this takes appropriate action based on
 313                          * sleep state received --
 314                          */
 315                         st_ll_sleep_state(st_gdata, *ptr);
 316                         /* if WAKEUP_IND collides copy from waitq to txq
 317                          * and assume chip awake
 318                          */
 319                         spin_unlock_irqrestore(&st_gdata->lock, flags);
 320                         if (st_ll_getstate(st_gdata) == ST_LL_AWAKE)
 321                                 st_wakeup_ack(st_gdata, LL_WAKE_UP_ACK);
 322                         spin_lock_irqsave(&st_gdata->lock, flags);
 323
 324                         ptr++;
 325                         count--;
 326                         continue;
 327                 case LL_WAKE_UP_ACK:
 328                         pr_debug("PM packet");
 329
 330                         spin_unlock_irqrestore(&st_gdata->lock, flags);
 331                         /* wake up ack received */
 332                         st_wakeup_ack(st_gdata, *ptr);
 333                         spin_lock_irqsave(&st_gdata->lock, flags);
 334
 335                         ptr++;
 336                         count--;
 337                         continue;
 338                         /* Unknow packet? */
 339                 default:
 340                         type = *ptr;
 341                         if (st_gdata->list[type] == NULL) {
 342                                 pr_err("chip/interface misbehavior dropping"
 343                                         " frame starting with 0x%02x", type);
 344                                 goto done;
 345
 346                         }
 347                         st_gdata->rx_skb = alloc_skb(
 348                                         st_gdata->list[type]->max_frame_size,
 349                                         GFP_ATOMIC);
 350                         skb_reserve(st_gdata->rx_skb,
 351                                         st_gdata->list[type]->reserve);
 352                         /* next 2 required for BT only */
 353                         st_gdata->rx_skb->cb[0] = type; /*pkt_type*/
 354                         st_gdata->rx_skb->cb[1] = 0; /*incoming*/
 355                         st_gdata->rx_chnl = *ptr;
 356                         st_gdata->rx_state = ST_W4_HEADER;
 357                         st_gdata->rx_count = st_gdata->list[type]->hdr_len;
 358                         pr_debug("rx_count %ld\n", st_gdata->rx_count);
 359                 };
 360                 ptr++;
 361                 count--;
 362         }
 363 done:
 364         spin_unlock_irqrestore(&st_gdata->lock, flags);
 365         pr_debug("done %s", __func__);
 366         return;
 367 }
 368
 369 /**
 370  * st_int_dequeue - internal de-Q function.
 371  *      If the previous data set was not written
 372  *      completely, return that skb which has the pending data.
 373  *      In normal cases, return top of txq.
 374  */
 375 struct sk_buff *st_int_dequeue(struct st_data_s *st_gdata)
 376 {
 377         struct sk_buff *returning_skb;
 378
 379         pr_debug("%s", __func__);
 380         if (st_gdata->tx_skb != NULL) {
 381                 returning_skb = st_gdata->tx_skb;
 382                 st_gdata->tx_skb = NULL;
 383                 return returning_skb;
 384         }
 385         return skb_dequeue(&st_gdata->txq);
 386 }
 387
 388 /**
 389  * st_int_enqueue - internal Q-ing function.
 390  *      Will either Q the skb to txq or the tx_waitq
 391  *      depending on the ST LL state.
 392  *      If the chip is asleep, then Q it onto waitq and
 393  *      wakeup the chip.
 394  *      txq and waitq needs protection since the other contexts
 395  *      may be sending data, waking up chip.
 396  */
 397 void st_int_enqueue(struct st_data_s *st_gdata, struct sk_buff *skb)
 398 {
 399         unsigned long flags = 0;
 400
 401         pr_debug("%s", __func__);
 402         spin_lock_irqsave(&st_gdata->lock, flags);
 403
 404         switch (st_ll_getstate(st_gdata)) {
 405         case ST_LL_AWAKE:
 406                 pr_debug("ST LL is AWAKE, sending normally");
 407                 skb_queue_tail(&st_gdata->txq, skb);
 408                 break;
 409         case ST_LL_ASLEEP_TO_AWAKE:
 410                 skb_queue_tail(&st_gdata->tx_waitq, skb);
 411                 break;
 412         case ST_LL_AWAKE_TO_ASLEEP:
 413                 pr_err("ST LL is illegal state(%ld),"
 414                            "purging received skb.", st_ll_getstate(st_gdata));
 415                 kfree_skb(skb);
 416                 break;
 417         case ST_LL_ASLEEP:
 418                 skb_queue_tail(&st_gdata->tx_waitq, skb);
 419                 st_ll_wakeup(st_gdata);
 420                 break;
 421         default:
 422                 pr_err("ST LL is illegal state(%ld),"
 423                            "purging received skb.", st_ll_getstate(st_gdata));
 424                 kfree_skb(skb);
 425                 break;
 426         }
 427
 428         spin_unlock_irqrestore(&st_gdata->lock, flags);
 429         pr_debug("done %s", __func__);
 430         return;
 431 }
 432
 433 /*
 434  * internal wakeup function
 435  * called from either
 436  * - TTY layer when write's finished
 437  * - st_write (in context of the protocol stack)
 438  */
 439 void st_tx_wakeup(struct st_data_s *st_data)
 440 {
 441         struct sk_buff *skb;
 442         unsigned long flags;    /* for irq save flags */
 443         pr_debug("%s", __func__);
 444         /* check for sending & set flag sending here */
 445         if (test_and_set_bit(ST_TX_SENDING, &st_data->tx_state)) {
 446                 pr_debug("ST already sending");
 447                 /* keep sending */
 448                 set_bit(ST_TX_WAKEUP, &st_data->tx_state);
 449                 return;
 450                 /* TX_WAKEUP will be checked in another
 451                  * context
 452                  */
 453         }
 454         do {                    /* come back if st_tx_wakeup is set */
 455                 /* woke-up to write */
 456                 clear_bit(ST_TX_WAKEUP, &st_data->tx_state);
 457                 while ((skb = st_int_dequeue(st_data))) {
 458                         int len;
 459                         spin_lock_irqsave(&st_data->lock, flags);
 460                         /* enable wake-up from TTY */
 461                         set_bit(TTY_DO_WRITE_WAKEUP, &st_data->tty->flags);
 462                         len = st_int_write(st_data, skb->data, skb->len);
 463                         skb_pull(skb, len);
 464                         /* if skb->len = len as expected, skb->len=0 */
 465                         if (skb->len) {
 466                                 /* would be the next skb to be sent */
 467                                 st_data->tx_skb = skb;
 468                                 spin_unlock_irqrestore(&st_data->lock, flags);
 469                                 break;
 470                         }
 471                         kfree_skb(skb);
 472                         spin_unlock_irqrestore(&st_data->lock, flags);
 473                 }
 474                 /* if wake-up is set in another context- restart sending */
 475         } while (test_bit(ST_TX_WAKEUP, &st_data->tx_state));
 476
 477         /* clear flag sending */
 478         clear_bit(ST_TX_SENDING, &st_data->tx_state);
 479 }
 480
 481 /********************************************************************/
 482 /* functions called from ST KIM
 483 */
 484 void kim_st_list_protocols(struct st_data_s *st_gdata, void *buf)
 485 {
 486         seq_printf(buf, "[%d]\nBT=%c\nFM=%c\nGPS=%c\n",
 487                         st_gdata->protos_registered,
 488                         st_gdata->is_registered[0x04] == true ? 'R' : 'U',
 489                         st_gdata->is_registered[0x08] == true ? 'R' : 'U',
 490                         st_gdata->is_registered[0x09] == true ? 'R' : 'U');
 491 }
 492
 493 /********************************************************************/
 494 /*
 495  * functions called from protocol stack drivers
 496  * to be EXPORT-ed
 497  */
 498 long st_register(struct st_proto_s *new_proto)
 499 {
 500         struct st_data_s        *st_gdata;
 501         long err = 0;
 502         unsigned long flags = 0;
 503
 504         st_kim_ref(&st_gdata, 0);
 505         pr_info("%s(%d) ", __func__, new_proto->chnl_id);
 506         if (st_gdata == NULL || new_proto == NULL || new_proto->recv == NULL
 507             || new_proto->reg_complete_cb == NULL) {
 508                 pr_err("gdata/new_proto/recv or reg_complete_cb not ready");
 509                 return -EINVAL;
 510         }
 511
 512         if (new_proto->chnl_id >= ST_MAX_CHANNELS) {
 513                 pr_err("chnl_id %d not supported", new_proto->chnl_id);
 514                 return -EPROTONOSUPPORT;
 515         }
 516
 517         if (st_gdata->is_registered[new_proto->chnl_id] == true) {
 518                 pr_err("chnl_id %d already registered", new_proto->chnl_id);
 519                 return -EALREADY;
 520         }
 521
 522         /* can be from process context only */
 523         spin_lock_irqsave(&st_gdata->lock, flags);
 524
 525         if (test_bit(ST_REG_IN_PROGRESS, &st_gdata->st_state)) {
 526                 pr_info(" ST_REG_IN_PROGRESS:%d ", new_proto->chnl_id);
 527                 /* fw download in progress */
 528
 529                 add_channel_to_table(st_gdata, new_proto);
 530                 st_gdata->protos_registered++;
 531                 new_proto->write = st_write;
 532
 533                 set_bit(ST_REG_PENDING, &st_gdata->st_state);
 534                 spin_unlock_irqrestore(&st_gdata->lock, flags);
 535                 return -EINPROGRESS;
 536         } else if (st_gdata->protos_registered == ST_EMPTY) {
 537                 pr_info(" chnl_id list empty :%d ", new_proto->chnl_id);
 538                 set_bit(ST_REG_IN_PROGRESS, &st_gdata->st_state);
 539                 st_recv = st_kim_recv;
 540
 541                 /* release lock previously held - re-locked below */
 542                 spin_unlock_irqrestore(&st_gdata->lock, flags);
 543
 544                 /* enable the ST LL - to set default chip state */
 545                 st_ll_enable(st_gdata);
 546                 /* this may take a while to complete
 547                  * since it involves BT fw download
 548                  */
 549                 err = st_kim_start(st_gdata->kim_data);
 550                 if (err != 0) {
 551                         clear_bit(ST_REG_IN_PROGRESS, &st_gdata->st_state);
 552                         if ((st_gdata->protos_registered != ST_EMPTY) &&
 553                             (test_bit(ST_REG_PENDING, &st_gdata->st_state))) {
 554                                 pr_err(" KIM failure complete callback ");
 555                                 st_reg_complete(st_gdata, err);
 556                         }
 557                         return -EINVAL;
 558                 }
 559
 560                 clear_bit(ST_REG_IN_PROGRESS, &st_gdata->st_state);
 561                 st_recv = st_int_recv;
 562
 563                 /* this is where all pending registration
 564                  * are signalled to be complete by calling callback functions
 565                  */
 566                 if ((st_gdata->protos_registered != ST_EMPTY) &&
 567                     (test_bit(ST_REG_PENDING, &st_gdata->st_state))) {
 568                         pr_debug(" call reg complete callback ");
 569                         st_reg_complete(st_gdata, 0);
 570                 }
 571                 clear_bit(ST_REG_PENDING, &st_gdata->st_state);
 572
 573                 /* check for already registered once more,
 574                  * since the above check is old
 575                  */
 576                 if (st_gdata->is_registered[new_proto->chnl_id] == true) {
 577                         pr_err(" proto %d already registered ",
 578                                    new_proto->chnl_id);
 579                         return -EALREADY;
 580                 }
 581
 582                 spin_lock_irqsave(&st_gdata->lock, flags);
 583                 add_channel_to_table(st_gdata, new_proto);
 584                 st_gdata->protos_registered++;
 585                 new_proto->write = st_write;
 586                 spin_unlock_irqrestore(&st_gdata->lock, flags);
 587                 return err;
 588         }
 589         /* if fw is already downloaded & new stack registers protocol */
 590         else {
 591                 add_channel_to_table(st_gdata, new_proto);
 592                 st_gdata->protos_registered++;
 593                 new_proto->write = st_write;
 594
 595                 /* lock already held before entering else */
 596                 spin_unlock_irqrestore(&st_gdata->lock, flags);
 597                 return err;
 598         }
 599         pr_debug("done %s(%d) ", __func__, new_proto->chnl_id);
 600 }
 601 EXPORT_SYMBOL_GPL(st_register);
 602
 603 /* to unregister a protocol -
 604  * to be called from protocol stack driver
 605  */
 606 long st_unregister(struct st_proto_s *proto)
 607 {
 608         long err = 0;
 609         unsigned long flags = 0;
 610         struct st_data_s        *st_gdata;
 611
 612         pr_debug("%s: %d ", __func__, proto->chnl_id);
 613
 614         st_kim_ref(&st_gdata, 0);
 615         if (!st_gdata || proto->chnl_id >= ST_MAX_CHANNELS) {
 616                 pr_err(" chnl_id %d not supported", proto->chnl_id);
 617                 return -EPROTONOSUPPORT;
 618         }
 619
 620         spin_lock_irqsave(&st_gdata->lock, flags);
 621
 622         if (st_gdata->list[proto->chnl_id] == NULL) {
 623                 pr_err(" chnl_id %d not registered", proto->chnl_id);
 624                 spin_unlock_irqrestore(&st_gdata->lock, flags);
 625                 return -EPROTONOSUPPORT;
 626         }
 627
 628         st_gdata->protos_registered--;
 629         remove_channel_from_table(st_gdata, proto);
 630         spin_unlock_irqrestore(&st_gdata->lock, flags);
 631
 632         if ((st_gdata->protos_registered == ST_EMPTY) &&
 633             (!test_bit(ST_REG_PENDING, &st_gdata->st_state))) {
 634                 pr_info(" all chnl_ids unregistered ");
 635
 636                 /* stop traffic on tty */
 637                 if (st_gdata->tty) {
 638                         tty_ldisc_flush(st_gdata->tty);
 639                         stop_tty(st_gdata->tty);
 640                 }
 641
 642                 /* all chnl_ids now unregistered */
 643                 st_kim_stop(st_gdata->kim_data);
 644                 /* disable ST LL */
 645                 st_ll_disable(st_gdata);
 646         }
 647         return err;
 648 }
 649
 650 /*
 651  * called in protocol stack drivers
 652  * via the write function pointer
 653  */
 654 long st_write(struct sk_buff *skb)
 655 {
 656         struct st_data_s *st_gdata;
 657         long len;
 658
 659         st_kim_ref(&st_gdata, 0);
 660         if (unlikely(skb == NULL || st_gdata == NULL
 661                 || st_gdata->tty == NULL)) {
 662                 pr_err("data/tty unavailable to perform write");
 663                 return -EINVAL;
 664         }
 665
 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->is_registered[i] == true)
 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