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 extern void st_kim_recv(void *, const unsigned char *, long);
  34 void st_int_recv(void *, const unsigned char *, long);
  35 /* function pointer pointing to either,
  36  * st_kim_recv during registration to receive fw download responses
  37  * st_int_recv after registration to receive proto stack responses
  38  */
  39 static void (*st_recv) (void *, const unsigned char *, long);
  40
  41 /********************************************************************/
  42 static void add_channel_to_table(struct st_data_s *st_gdata,
  43                 struct st_proto_s *new_proto)
  44 {
  45         pr_info("%s: id %d\n", __func__, new_proto->chnl_id);
  46         /* list now has the channel id as index itself */
  47         st_gdata->list[new_proto->chnl_id] = new_proto;
  48         st_gdata->is_registered[new_proto->chnl_id] = true;
  49 }
  50
  51 static void remove_channel_from_table(struct st_data_s *st_gdata,
  52                 struct st_proto_s *proto)
  53 {
  54         pr_info("%s: id %d\n", __func__, proto->chnl_id);
  55 /*      st_gdata->list[proto->chnl_id] = NULL; */
  56         st_gdata->is_registered[proto->chnl_id] = false;
  57 }
  58
  59 /*
  60  * called from KIM during firmware download.
  61  *
  62  * This is a wrapper function to tty->ops->write_room.
  63  * It returns number of free space available in
  64  * uart tx buffer.
  65  */
  66 int st_get_uart_wr_room(struct st_data_s *st_gdata)
  67 {
  68         struct tty_struct *tty;
  69         if (unlikely(st_gdata == NULL || st_gdata->tty == NULL)) {
  70                 pr_err("tty unavailable to perform write");
  71                 return -1;
  72         }
  73         tty = st_gdata->tty;
  74         return tty->ops->write_room(tty);
  75 }
  76
  77 /* can be called in from
  78  * -- KIM (during fw download)
  79  * -- ST Core (during st_write)
  80  *
  81  *  This is the internal write function - a wrapper
  82  *  to tty->ops->write
  83  */
  84 int st_int_write(struct st_data_s *st_gdata,
  85         const unsigned char *data, int count)
  86 {
  87         struct tty_struct *tty;
  88         if (unlikely(st_gdata == NULL || st_gdata->tty == NULL)) {
  89                 pr_err("tty unavailable to perform write");
  90                 return -EINVAL;
  91         }
  92         tty = st_gdata->tty;
  93 #ifdef VERBOSE
  94         print_hex_dump(KERN_DEBUG, "<out<", DUMP_PREFIX_NONE,
  95                 16, 1, data, count, 0);
  96 #endif
  97         return tty->ops->write(tty, data, count);
  98
  99 }
 100
 101 /*
 102  * push the skb received to relevant
 103  * protocol stacks
 104  */
 105 static void st_send_frame(unsigned char chnl_id, struct st_data_s *st_gdata)
 106 {
 107         pr_debug(" %s(prot:%d) ", __func__, chnl_id);
 108
 109         if (unlikely
 110             (st_gdata == NULL || st_gdata->rx_skb == NULL
 111              || st_gdata->is_registered[chnl_id] == false)) {
 112                 pr_err("chnl_id %d not registered, no data to send?",
 113                            chnl_id);
 114                 kfree_skb(st_gdata->rx_skb);
 115                 return;
 116         }
 117         /* this cannot fail
 118          * this shouldn't take long
 119          * - should be just skb_queue_tail for the
 120          *   protocol stack driver
 121          */
 122         if (likely(st_gdata->list[chnl_id]->recv != NULL)) {
 123                 if (unlikely
 124                         (st_gdata->list[chnl_id]->recv
 125                         (st_gdata->list[chnl_id]->priv_data, st_gdata->rx_skb)
 126                              != 0)) {
 127                         pr_err(" proto stack %d's ->recv failed", chnl_id);
 128                         kfree_skb(st_gdata->rx_skb);
 129                         return;
 130                 }
 131         } else {
 132                 pr_err(" proto stack %d's ->recv null", chnl_id);
 133                 kfree_skb(st_gdata->rx_skb);
 134         }
 135         return;
 136 }
 137
 138 /**
 139  * st_reg_complete -
 140  * to call registration complete callbacks
 141  * of all protocol stack drivers
 142  * This function is being called with spin lock held, protocol drivers are
 143  * only expected to complete their waits and do nothing more than that.
 144  */
 145 static void st_reg_complete(struct st_data_s *st_gdata, char err)
 146 {
 147         unsigned char i = 0;
 148         pr_info(" %s ", __func__);
 149         for (i = 0; i < ST_MAX_CHANNELS; i++) {
 150                 if (likely(st_gdata != NULL &&
 151                         st_gdata->is_registered[i] == true &&
 152                                 st_gdata->list[i]->reg_complete_cb != NULL)) {
 153                         st_gdata->list[i]->reg_complete_cb
 154                                 (st_gdata->list[i]->priv_data, err);
 155                         pr_info("protocol %d's cb sent %d\n", i, err);
 156                         if (err) { /* cleanup registered protocol */
 157                                 st_gdata->protos_registered--;
 158                                 st_gdata->is_registered[i] = false;
 159                         }
 160                 }
 161         }
 162 }
 163
 164 static inline int st_check_data_len(struct st_data_s *st_gdata,
 165         unsigned char chnl_id, int len)
 166 {
 167         int room = skb_tailroom(st_gdata->rx_skb);
 168
 169         pr_debug("len %d room %d", len, room);
 170
 171         if (!len) {
 172                 /* Received packet has only packet header and
 173                  * has zero length payload. So, ask ST CORE to
 174                  * forward the packet to protocol driver (BT/FM/GPS)
 175                  */
 176                 st_send_frame(chnl_id, st_gdata);
 177
 178         } else if (len > room) {
 179                 /* Received packet's payload length is larger.
 180                  * We can't accommodate it in created skb.
 181                  */
 182                 pr_err("Data length is too large len %d room %d", len,
 183                            room);
 184                 kfree_skb(st_gdata->rx_skb);
 185         } else {
 186                 /* Packet header has non-zero payload length and
 187                  * we have enough space in created skb. Lets read
 188                  * payload data */
 189                 st_gdata->rx_state = ST_W4_DATA;
 190                 st_gdata->rx_count = len;
 191                 return len;
 192         }
 193
 194         /* Change ST state to continue to process next
 195          * packet */
 196         st_gdata->rx_state = ST_W4_PACKET_TYPE;
 197         st_gdata->rx_skb = NULL;
 198         st_gdata->rx_count = 0;
 199         st_gdata->rx_chnl = 0;
 200
 201         return 0;
 202 }
 203
 204 /**
 205  * st_wakeup_ack - internal function for action when wake-up ack
 206  *      received
 207  */
 208 static inline void st_wakeup_ack(struct st_data_s *st_gdata,
 209         unsigned char cmd)
 210 {
 211         struct sk_buff *waiting_skb;
 212         unsigned long flags = 0;
 213
 214         spin_lock_irqsave(&st_gdata->lock, flags);
 215         /* de-Q from waitQ and Q in txQ now that the
 216          * chip is awake
 217          */
 218         while ((waiting_skb = skb_dequeue(&st_gdata->tx_waitq)))
 219                 skb_queue_tail(&st_gdata->txq, waiting_skb);
 220
 221         /* state forwarded to ST LL */
 222         st_ll_sleep_state(st_gdata, (unsigned long)cmd);
 223         spin_unlock_irqrestore(&st_gdata->lock, flags);
 224
 225         /* wake up to send the recently copied skbs from waitQ */
 226         st_tx_wakeup(st_gdata);
 227 }
 228
 229 /**
 230  * st_int_recv - ST's internal receive function.
 231  *      Decodes received RAW data and forwards to corresponding
 232  *      client drivers (Bluetooth,FM,GPS..etc).
 233  *      This can receive various types of packets,
 234  *      HCI-Events, ACL, SCO, 4 types of HCI-LL PM packets
 235  *      CH-8 packets from FM, CH-9 packets from GPS cores.
 236  */
 237 void st_int_recv(void *disc_data,
 238         const unsigned char *data, long count)
 239 {
 240         char *ptr;
 241         struct st_proto_s *proto;
 242         unsigned short payload_len = 0;
 243         int len = 0;
 244         unsigned char type = 0;
 245         unsigned char *plen;
 246         struct st_data_s *st_gdata = (struct st_data_s *)disc_data;
 247         unsigned long flags;
 248
 249         ptr = (char *)data;
 250         /* tty_receive sent null ? */
 251         if (unlikely(ptr == NULL) || (st_gdata == NULL)) {
 252                 pr_err(" received null from TTY ");
 253                 return;
 254         }
 255
 256         pr_debug("count %ld rx_state %ld"
 257                    "rx_count %ld", count, st_gdata->rx_state,
 258                    st_gdata->rx_count);
 259
 260         spin_lock_irqsave(&st_gdata->lock, flags);
 261         /* Decode received bytes here */
 262         while (count) {
 263                 if (st_gdata->rx_count) {
 264                         len = min_t(unsigned int, st_gdata->rx_count, count);
 265                         memcpy(skb_put(st_gdata->rx_skb, len), ptr, len);
 266                         st_gdata->rx_count -= len;
 267                         count -= len;
 268                         ptr += len;
 269
 270                         if (st_gdata->rx_count)
 271                                 continue;
 272
 273                         /* Check ST RX state machine , where are we? */
 274                         switch (st_gdata->rx_state) {
 275                         /* Waiting for complete packet ? */
 276                         case ST_W4_DATA:
 277                                 pr_debug("Complete pkt received");
 278                                 /* Ask ST CORE to forward
 279                                  * the packet to protocol driver */
 280                                 st_send_frame(st_gdata->rx_chnl, st_gdata);
 281
 282                                 st_gdata->rx_state = ST_W4_PACKET_TYPE;
 283                                 st_gdata->rx_skb = NULL;
 284                                 continue;
 285                         /* parse the header to know details */
 286                         case ST_W4_HEADER:
 287                                 proto = st_gdata->list[st_gdata->rx_chnl];
 288                                 plen =
 289                                 &st_gdata->rx_skb->data
 290                                 [proto->offset_len_in_hdr];
 291                                 pr_debug("plen pointing to %x\n", *plen);
 292                                 if (proto->len_size == 1)/* 1 byte len field */
 293                                         payload_len = *(unsigned char *)plen;
 294                                 else if (proto->len_size == 2)
 295                                         payload_len =
 296                                         __le16_to_cpu(*(unsigned short *)plen);
 297                                 else
 298                                         pr_info("%s: invalid length "
 299                                         "for id %d\n",
 300                                         __func__, proto->chnl_id);
 301                                 st_check_data_len(st_gdata, proto->chnl_id,
 302                                                 payload_len);
 303                                 pr_debug("off %d, pay len %d\n",
 304                                         proto->offset_len_in_hdr, payload_len);
 305                                 continue;
 306                         }       /* end of switch rx_state */
 307                 }
 308
 309                 /* end of if rx_count */
 310                 /* Check first byte of packet and identify module
 311                  * owner (BT/FM/GPS) */
 312                 switch (*ptr) {
 313                 case LL_SLEEP_IND:
 314                 case LL_SLEEP_ACK:
 315                 case LL_WAKE_UP_IND:
 316                         pr_debug("PM packet");
 317                         /* this takes appropriate action based on
 318                          * sleep state received --
 319                          */
 320                         st_ll_sleep_state(st_gdata, *ptr);
 321                         /* if WAKEUP_IND collides copy from waitq to txq
 322                          * and assume chip awake
 323                          */
 324                         spin_unlock_irqrestore(&st_gdata->lock, flags);
 325                         if (st_ll_getstate(st_gdata) == ST_LL_AWAKE)
 326                                 st_wakeup_ack(st_gdata, LL_WAKE_UP_ACK);
 327                         spin_lock_irqsave(&st_gdata->lock, flags);
 328
 329                         ptr++;
 330                         count--;
 331                         continue;
 332                 case LL_WAKE_UP_ACK:
 333                         pr_debug("PM packet");
 334
 335                         spin_unlock_irqrestore(&st_gdata->lock, flags);
 336                         /* wake up ack received */
 337                         st_wakeup_ack(st_gdata, *ptr);
 338                         spin_lock_irqsave(&st_gdata->lock, flags);
 339
 340                         ptr++;
 341                         count--;
 342                         continue;
 343                         /* Unknow packet? */
 344                 default:
 345                         type = *ptr;
 346                         if (st_gdata->list[type] == NULL) {
 347                                 pr_err("chip/interface misbehavior dropping"
 348                                         " frame starting with 0x%02x", type);
 349                                 goto done;
 350
 351                         }
 352                         st_gdata->rx_skb = alloc_skb(
 353                                         st_gdata->list[type]->max_frame_size,
 354                                         GFP_ATOMIC);
 355                         if (st_gdata->rx_skb == NULL) {
 356                                 pr_err("out of memory: dropping\n");
 357                                 goto done;
 358                         }
 359
 360                         skb_reserve(st_gdata->rx_skb,
 361                                         st_gdata->list[type]->reserve);
 362                         /* next 2 required for BT only */
 363                         st_gdata->rx_skb->cb[0] = type; /*pkt_type*/
 364                         st_gdata->rx_skb->cb[1] = 0; /*incoming*/
 365                         st_gdata->rx_chnl = *ptr;
 366                         st_gdata->rx_state = ST_W4_HEADER;
 367                         st_gdata->rx_count = st_gdata->list[type]->hdr_len;
 368                         pr_debug("rx_count %ld\n", st_gdata->rx_count);
 369                 };
 370                 ptr++;
 371                 count--;
 372         }
 373 done:
 374         spin_unlock_irqrestore(&st_gdata->lock, flags);
 375         pr_debug("done %s", __func__);
 376         return;
 377 }
 378
 379 /**
 380  * st_int_dequeue - internal de-Q function.
 381  *      If the previous data set was not written
 382  *      completely, return that skb which has the pending data.
 383  *      In normal cases, return top of txq.
 384  */
 385 static struct sk_buff *st_int_dequeue(struct st_data_s *st_gdata)
 386 {
 387         struct sk_buff *returning_skb;
 388
 389         pr_debug("%s", __func__);
 390         if (st_gdata->tx_skb != NULL) {
 391                 returning_skb = st_gdata->tx_skb;
 392                 st_gdata->tx_skb = NULL;
 393                 return returning_skb;
 394         }
 395         return skb_dequeue(&st_gdata->txq);
 396 }
 397
 398 /**
 399  * st_int_enqueue - internal Q-ing function.
 400  *      Will either Q the skb to txq or the tx_waitq
 401  *      depending on the ST LL state.
 402  *      If the chip is asleep, then Q it onto waitq and
 403  *      wakeup the chip.
 404  *      txq and waitq needs protection since the other contexts
 405  *      may be sending data, waking up chip.
 406  */
 407 static void st_int_enqueue(struct st_data_s *st_gdata, struct sk_buff *skb)
 408 {
 409         unsigned long flags = 0;
 410
 411         pr_debug("%s", __func__);
 412         spin_lock_irqsave(&st_gdata->lock, flags);
 413
 414         switch (st_ll_getstate(st_gdata)) {
 415         case ST_LL_AWAKE:
 416                 pr_debug("ST LL is AWAKE, sending normally");
 417                 skb_queue_tail(&st_gdata->txq, skb);
 418                 break;
 419         case ST_LL_ASLEEP_TO_AWAKE:
 420                 skb_queue_tail(&st_gdata->tx_waitq, skb);
 421                 break;
 422         case ST_LL_AWAKE_TO_ASLEEP:
 423                 pr_err("ST LL is illegal state(%ld),"
 424                            "purging received skb.", st_ll_getstate(st_gdata));
 425                 kfree_skb(skb);
 426                 break;
 427         case ST_LL_ASLEEP:
 428                 skb_queue_tail(&st_gdata->tx_waitq, skb);
 429                 st_ll_wakeup(st_gdata);
 430                 break;
 431         default:
 432                 pr_err("ST LL is illegal state(%ld),"
 433                            "purging received skb.", st_ll_getstate(st_gdata));
 434                 kfree_skb(skb);
 435                 break;
 436         }
 437
 438         spin_unlock_irqrestore(&st_gdata->lock, flags);
 439         pr_debug("done %s", __func__);
 440         return;
 441 }
 442
 443 /*
 444  * internal wakeup function
 445  * called from either
 446  * - TTY layer when write's finished
 447  * - st_write (in context of the protocol stack)
 448  */
 449 void st_tx_wakeup(struct st_data_s *st_data)
 450 {
 451         struct sk_buff *skb;
 452         unsigned long flags;    /* for irq save flags */
 453         pr_debug("%s", __func__);
 454         /* check for sending & set flag sending here */
 455         if (test_and_set_bit(ST_TX_SENDING, &st_data->tx_state)) {
 456                 pr_debug("ST already sending");
 457                 /* keep sending */
 458                 set_bit(ST_TX_WAKEUP, &st_data->tx_state);
 459                 return;
 460                 /* TX_WAKEUP will be checked in another
 461                  * context
 462                  */
 463         }
 464         do {                    /* come back if st_tx_wakeup is set */
 465                 /* woke-up to write */
 466                 clear_bit(ST_TX_WAKEUP, &st_data->tx_state);
 467                 while ((skb = st_int_dequeue(st_data))) {
 468                         int len;
 469                         spin_lock_irqsave(&st_data->lock, flags);
 470                         /* enable wake-up from TTY */
 471                         set_bit(TTY_DO_WRITE_WAKEUP, &st_data->tty->flags);
 472                         len = st_int_write(st_data, skb->data, skb->len);
 473                         skb_pull(skb, len);
 474                         /* if skb->len = len as expected, skb->len=0 */
 475                         if (skb->len) {
 476                                 /* would be the next skb to be sent */
 477                                 st_data->tx_skb = skb;
 478                                 spin_unlock_irqrestore(&st_data->lock, flags);
 479                                 break;
 480                         }
 481                         kfree_skb(skb);
 482                         spin_unlock_irqrestore(&st_data->lock, flags);
 483                 }
 484                 /* if wake-up is set in another context- restart sending */
 485         } while (test_bit(ST_TX_WAKEUP, &st_data->tx_state));
 486
 487         /* clear flag sending */
 488         clear_bit(ST_TX_SENDING, &st_data->tx_state);
 489 }
 490
 491 /********************************************************************/
 492 /* functions called from ST KIM
 493 */
 494 void kim_st_list_protocols(struct st_data_s *st_gdata, void *buf)
 495 {
 496         seq_printf(buf, "[%d]\nBT=%c\nFM=%c\nGPS=%c\n",
 497                         st_gdata->protos_registered,
 498                         st_gdata->is_registered[0x04] == true ? 'R' : 'U',
 499                         st_gdata->is_registered[0x08] == true ? 'R' : 'U',
 500                         st_gdata->is_registered[0x09] == true ? 'R' : 'U');
 501 }
 502
 503 /********************************************************************/
 504 /*
 505  * functions called from protocol stack drivers
 506  * to be EXPORT-ed
 507  */
 508 long st_register(struct st_proto_s *new_proto)
 509 {
 510         struct st_data_s        *st_gdata;
 511         long err = 0;
 512         unsigned long flags = 0;
 513
 514         st_kim_ref(&st_gdata, 0);
 515         if (st_gdata == NULL || new_proto == NULL || new_proto->recv == NULL
 516             || new_proto->reg_complete_cb == NULL) {
 517                 pr_err("gdata/new_proto/recv or reg_complete_cb not ready");
 518                 return -EINVAL;
 519         }
 520
 521         if (new_proto->chnl_id >= ST_MAX_CHANNELS) {
 522                 pr_err("chnl_id %d not supported", new_proto->chnl_id);
 523                 return -EPROTONOSUPPORT;
 524         }
 525
 526         if (st_gdata->is_registered[new_proto->chnl_id] == true) {
 527                 pr_err("chnl_id %d already registered", new_proto->chnl_id);
 528                 return -EALREADY;
 529         }
 530
 531         /* can be from process context only */
 532         spin_lock_irqsave(&st_gdata->lock, flags);
 533
 534         if (test_bit(ST_REG_IN_PROGRESS, &st_gdata->st_state)) {
 535                 pr_info(" ST_REG_IN_PROGRESS:%d ", new_proto->chnl_id);
 536                 /* fw download in progress */
 537
 538                 add_channel_to_table(st_gdata, new_proto);
 539                 st_gdata->protos_registered++;
 540                 new_proto->write = st_write;
 541
 542                 set_bit(ST_REG_PENDING, &st_gdata->st_state);
 543                 spin_unlock_irqrestore(&st_gdata->lock, flags);
 544                 return -EINPROGRESS;
 545         } else if (st_gdata->protos_registered == ST_EMPTY) {
 546                 pr_info(" chnl_id list empty :%d ", new_proto->chnl_id);
 547                 set_bit(ST_REG_IN_PROGRESS, &st_gdata->st_state);
 548                 st_recv = st_kim_recv;
 549
 550                 /* enable the ST LL - to set default chip state */
 551                 st_ll_enable(st_gdata);
 552
 553                 /* release lock previously held - re-locked below */
 554                 spin_unlock_irqrestore(&st_gdata->lock, flags);
 555
 556                 /* this may take a while to complete
 557                  * since it involves BT fw download
 558                  */
 559                 err = st_kim_start(st_gdata->kim_data);
 560                 if (err != 0) {
 561                         clear_bit(ST_REG_IN_PROGRESS, &st_gdata->st_state);
 562                         if ((st_gdata->protos_registered != ST_EMPTY) &&
 563                             (test_bit(ST_REG_PENDING, &st_gdata->st_state))) {
 564                                 pr_err(" KIM failure complete callback ");
 565                                 st_reg_complete(st_gdata, err);
 566                                 clear_bit(ST_REG_PENDING, &st_gdata->st_state);
 567                         }
 568                         return -EINVAL;
 569                 }
 570
 571                 spin_lock_irqsave(&st_gdata->lock, flags);
 572
 573                 clear_bit(ST_REG_IN_PROGRESS, &st_gdata->st_state);
 574                 st_recv = st_int_recv;
 575
 576                 /* this is where all pending registration
 577                  * are signalled to be complete by calling callback functions
 578                  */
 579                 if ((st_gdata->protos_registered != ST_EMPTY) &&
 580                     (test_bit(ST_REG_PENDING, &st_gdata->st_state))) {
 581                         pr_debug(" call reg complete callback ");
 582                         st_reg_complete(st_gdata, 0);
 583                 }
 584                 clear_bit(ST_REG_PENDING, &st_gdata->st_state);
 585
 586                 /* check for already registered once more,
 587                  * since the above check is old
 588                  */
 589                 if (st_gdata->is_registered[new_proto->chnl_id] == true) {
 590                         pr_err(" proto %d already registered ",
 591                                    new_proto->chnl_id);
 592                         spin_unlock_irqrestore(&st_gdata->lock, flags);
 593                         return -EALREADY;
 594                 }
 595
 596                 add_channel_to_table(st_gdata, new_proto);
 597                 st_gdata->protos_registered++;
 598                 new_proto->write = st_write;
 599                 spin_unlock_irqrestore(&st_gdata->lock, flags);
 600                 return err;
 601         }
 602         /* if fw is already downloaded & new stack registers protocol */
 603         else {
 604                 add_channel_to_table(st_gdata, new_proto);
 605                 st_gdata->protos_registered++;
 606                 new_proto->write = st_write;
 607
 608                 /* lock already held before entering else */
 609                 spin_unlock_irqrestore(&st_gdata->lock, flags);
 610                 return err;
 611         }
 612         pr_debug("done %s(%d) ", __func__, new_proto->chnl_id);
 613 }
 614 EXPORT_SYMBOL_GPL(st_register);
 615
 616 /* to unregister a protocol -
 617  * to be called from protocol stack driver
 618  */
 619 long st_unregister(struct st_proto_s *proto)
 620 {
 621         long err = 0;
 622         unsigned long flags = 0;
 623         struct st_data_s        *st_gdata;
 624
 625         pr_debug("%s: %d ", __func__, proto->chnl_id);
 626
 627         st_kim_ref(&st_gdata, 0);
 628         if (!st_gdata || proto->chnl_id >= ST_MAX_CHANNELS) {
 629                 pr_err(" chnl_id %d not supported", proto->chnl_id);
 630                 return -EPROTONOSUPPORT;
 631         }
 632
 633         spin_lock_irqsave(&st_gdata->lock, flags);
 634
 635         if (st_gdata->is_registered[proto->chnl_id] == false) {
 636                 pr_err(" chnl_id %d not registered", proto->chnl_id);
 637                 spin_unlock_irqrestore(&st_gdata->lock, flags);
 638                 return -EPROTONOSUPPORT;
 639         }
 640
 641         st_gdata->protos_registered--;
 642         remove_channel_from_table(st_gdata, proto);
 643         spin_unlock_irqrestore(&st_gdata->lock, flags);
 644
 645         /* paranoid check */
 646         if (st_gdata->protos_registered < ST_EMPTY)
 647                 st_gdata->protos_registered = ST_EMPTY;
 648
 649         if ((st_gdata->protos_registered == ST_EMPTY) &&
 650             (!test_bit(ST_REG_PENDING, &st_gdata->st_state))) {
 651                 pr_info(" all chnl_ids unregistered ");
 652
 653                 /* stop traffic on tty */
 654                 if (st_gdata->tty) {
 655                         tty_ldisc_flush(st_gdata->tty);
 656                         stop_tty(st_gdata->tty);
 657                 }
 658
 659                 /* all chnl_ids now unregistered */
 660                 st_kim_stop(st_gdata->kim_data);
 661                 /* disable ST LL */
 662                 st_ll_disable(st_gdata);
 663         }
 664         return err;
 665 }
 666
 667 /*
 668  * called in protocol stack drivers
 669  * via the write function pointer
 670  */
 671 long st_write(struct sk_buff *skb)
 672 {
 673         struct st_data_s *st_gdata;
 674         long len;
 675
 676         st_kim_ref(&st_gdata, 0);
 677         if (unlikely(skb == NULL || st_gdata == NULL
 678                 || st_gdata->tty == NULL)) {
 679                 pr_err("data/tty unavailable to perform write");
 680                 return -EINVAL;
 681         }
 682
 683         pr_debug("%d to be written", skb->len);
 684         len = skb->len;
 685
 686         /* st_ll to decide where to enqueue the skb */
 687         st_int_enqueue(st_gdata, skb);
 688         /* wake up */
 689         st_tx_wakeup(st_gdata);
 690
 691         /* return number of bytes written */
 692         return len;
 693 }
 694
 695 /* for protocols making use of shared transport */
 696 EXPORT_SYMBOL_GPL(st_unregister);
 697
 698 /********************************************************************/
 699 /*
 700  * functions called from TTY layer
 701  */
 702 static int st_tty_open(struct tty_struct *tty)
 703 {
 704         int err = 0;
 705         struct st_data_s *st_gdata;
 706         pr_info("%s ", __func__);
 707
 708         st_kim_ref(&st_gdata, 0);
 709         st_gdata->tty = tty;
 710         tty->disc_data = st_gdata;
 711
 712         /* don't do an wakeup for now */
 713         clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
 714
 715         /* mem already allocated
 716          */
 717         tty->receive_room = 65536;
 718         /* Flush any pending characters in the driver and discipline. */
 719         tty_ldisc_flush(tty);
 720         tty_driver_flush_buffer(tty);
 721         /*
 722          * signal to UIM via KIM that -
 723          * installation of N_TI_WL ldisc is complete
 724          */
 725         st_kim_complete(st_gdata->kim_data);
 726         pr_debug("done %s", __func__);
 727         return err;
 728 }
 729
 730 static void st_tty_close(struct tty_struct *tty)
 731 {
 732         unsigned char i = ST_MAX_CHANNELS;
 733         unsigned long flags = 0;
 734         struct  st_data_s *st_gdata = tty->disc_data;
 735
 736         pr_info("%s ", __func__);
 737
 738         /* TODO:
 739          * if a protocol has been registered & line discipline
 740          * un-installed for some reason - what should be done ?
 741          */
 742         spin_lock_irqsave(&st_gdata->lock, flags);
 743         for (i = ST_BT; i < ST_MAX_CHANNELS; i++) {
 744                 if (st_gdata->is_registered[i] == true)
 745                         pr_err("%d not un-registered", i);
 746                 st_gdata->list[i] = NULL;
 747                 st_gdata->is_registered[i] = false;
 748         }
 749         st_gdata->protos_registered = 0;
 750         spin_unlock_irqrestore(&st_gdata->lock, flags);
 751         /*
 752          * signal to UIM via KIM that -
 753          * N_TI_WL ldisc is un-installed
 754          */
 755         st_kim_complete(st_gdata->kim_data);
 756         st_gdata->tty = NULL;
 757         /* Flush any pending characters in the driver and discipline. */
 758         tty_ldisc_flush(tty);
 759         tty_driver_flush_buffer(tty);
 760
 761         spin_lock_irqsave(&st_gdata->lock, flags);
 762         /* empty out txq and tx_waitq */
 763         skb_queue_purge(&st_gdata->txq);
 764         skb_queue_purge(&st_gdata->tx_waitq);
 765         /* reset the TTY Rx states of ST */
 766         st_gdata->rx_count = 0;
 767         st_gdata->rx_state = ST_W4_PACKET_TYPE;
 768         kfree_skb(st_gdata->rx_skb);
 769         st_gdata->rx_skb = NULL;
 770         spin_unlock_irqrestore(&st_gdata->lock, flags);
 771
 772         pr_debug("%s: done ", __func__);
 773 }
 774
 775 static void st_tty_receive(struct tty_struct *tty, const unsigned char *data,
 776                            char *tty_flags, int count)
 777 {
 778 #ifdef VERBOSE
 779         print_hex_dump(KERN_DEBUG, ">in>", DUMP_PREFIX_NONE,
 780                 16, 1, data, count, 0);
 781 #endif
 782
 783         /*
 784          * if fw download is in progress then route incoming data
 785          * to KIM for validation
 786          */
 787         st_recv(tty->disc_data, data, count);
 788         pr_debug("done %s", __func__);
 789 }
 790
 791 /* wake-up function called in from the TTY layer
 792  * inside the internal wakeup function will be called
 793  */
 794 static void st_tty_wakeup(struct tty_struct *tty)
 795 {
 796         struct  st_data_s *st_gdata = tty->disc_data;
 797         pr_debug("%s ", __func__);
 798         /* don't do an wakeup for now */
 799         clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
 800
 801         /* call our internal wakeup */
 802         st_tx_wakeup((void *)st_gdata);
 803 }
 804
 805 static void st_tty_flush_buffer(struct tty_struct *tty)
 806 {
 807         struct  st_data_s *st_gdata = tty->disc_data;
 808         pr_debug("%s ", __func__);
 809
 810         kfree_skb(st_gdata->tx_skb);
 811         st_gdata->tx_skb = NULL;
 812
 813         tty->ops->flush_buffer(tty);
 814         return;
 815 }
 816
 817 static struct tty_ldisc_ops st_ldisc_ops = {
 818         .magic = TTY_LDISC_MAGIC,
 819         .name = "n_st",
 820         .open = st_tty_open,
 821         .close = st_tty_close,
 822         .receive_buf = st_tty_receive,
 823         .write_wakeup = st_tty_wakeup,
 824         .flush_buffer = st_tty_flush_buffer,
 825         .owner = THIS_MODULE
 826 };
 827
 828 /********************************************************************/
 829 int st_core_init(struct st_data_s **core_data)
 830 {
 831         struct st_data_s *st_gdata;
 832         long err;
 833
 834         err = tty_register_ldisc(N_TI_WL, &st_ldisc_ops);
 835         if (err) {
 836                 pr_err("error registering %d line discipline %ld",
 837                            N_TI_WL, err);
 838                 return err;
 839         }
 840         pr_debug("registered n_shared line discipline");
 841
 842         st_gdata = kzalloc(sizeof(struct st_data_s), GFP_KERNEL);
 843         if (!st_gdata) {
 844                 pr_err("memory allocation failed");
 845                 err = tty_unregister_ldisc(N_TI_WL);
 846                 if (err)
 847                         pr_err("unable to un-register ldisc %ld", err);
 848                 err = -ENOMEM;
 849                 return err;
 850         }
 851
 852         /* Initialize ST TxQ and Tx waitQ queue head. All BT/FM/GPS module skb's
 853          * will be pushed in this queue for actual transmission.
 854          */
 855         skb_queue_head_init(&st_gdata->txq);
 856         skb_queue_head_init(&st_gdata->tx_waitq);
 857
 858         /* Locking used in st_int_enqueue() to avoid multiple execution */
 859         spin_lock_init(&st_gdata->lock);
 860
 861         err = st_ll_init(st_gdata);
 862         if (err) {
 863                 pr_err("error during st_ll initialization(%ld)", err);
 864                 kfree(st_gdata);
 865                 err = tty_unregister_ldisc(N_TI_WL);
 866                 if (err)
 867                         pr_err("unable to un-register ldisc");
 868                 return err;
 869         }
 870         *core_data = st_gdata;
 871         return 0;
 872 }
 873
 874 void st_core_exit(struct st_data_s *st_gdata)
 875 {
 876         long err;
 877         /* internal module cleanup */
 878         err = st_ll_deinit(st_gdata);
 879         if (err)
 880                 pr_err("error during deinit of ST LL %ld", err);
 881
 882         if (st_gdata != NULL) {
 883                 /* Free ST Tx Qs and skbs */
 884                 skb_queue_purge(&st_gdata->txq);
 885                 skb_queue_purge(&st_gdata->tx_waitq);
 886                 kfree_skb(st_gdata->rx_skb);
 887                 kfree_skb(st_gdata->tx_skb);
 888                 /* TTY ldisc cleanup */
 889                 err = tty_unregister_ldisc(N_TI_WL);
 890                 if (err)
 891                         pr_err("unable to un-register ldisc %ld", err);
 892                 /* free the global data pointer */
 893                 kfree(st_gdata);
 894         }
 895 }
 896
 897