drivers/misc/ti-st/st_core.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  *  Shared Transport Line discipline driver Core
   4  *      This hooks up ST KIM driver and ST LL driver
   5  *  Copyright (C) 2009-2010 Texas Instruments
   6  *  Author: Pavan Savoy <[email protected]>
   7  */
   8
   9 #define pr_fmt(fmt)     "(stc): " fmt
  10 #include <linux/module.h>
  11 #include <linux/kernel.h>
  12 #include <linux/tty.h>
  13
  14 #include <linux/seq_file.h>
  15 #include <linux/skbuff.h>
  16
  17 #include <linux/ti_wilink_st.h>
  18
  19 extern void st_kim_recv(void *, const unsigned char *, long);
  20 void st_int_recv(void *, const unsigned char *, long);
  21 /*
  22  * function pointer pointing to either,
  23  * st_kim_recv during registration to receive fw download responses
  24  * st_int_recv after registration to receive proto stack responses
  25  */
  26 static void (*st_recv) (void *, const unsigned char *, long);
  27
  28 /********************************************************************/
  29 static void add_channel_to_table(struct st_data_s *st_gdata,
  30                 struct st_proto_s *new_proto)
  31 {
  32         pr_info("%s: id %d\n", __func__, new_proto->chnl_id);
  33         /* list now has the channel id as index itself */
  34         st_gdata->list[new_proto->chnl_id] = new_proto;
  35         st_gdata->is_registered[new_proto->chnl_id] = true;
  36 }
  37
  38 static void remove_channel_from_table(struct st_data_s *st_gdata,
  39                 struct st_proto_s *proto)
  40 {
  41         pr_info("%s: id %d\n", __func__, proto->chnl_id);
  42 /*      st_gdata->list[proto->chnl_id] = NULL; */
  43         st_gdata->is_registered[proto->chnl_id] = false;
  44 }
  45
  46 /*
  47  * called from KIM during firmware download.
  48  *
  49  * This is a wrapper function to tty->ops->write_room.
  50  * It returns number of free space available in
  51  * uart tx buffer.
  52  */
  53 int st_get_uart_wr_room(struct st_data_s *st_gdata)
  54 {
  55         if (unlikely(st_gdata == NULL || st_gdata->tty == NULL)) {
  56                 pr_err("tty unavailable to perform write");
  57                 return -1;
  58         }
  59
  60         return tty_write_room(st_gdata->tty);
  61 }
  62
  63 /*
  64  * can be called in from
  65  * -- KIM (during fw download)
  66  * -- ST Core (during st_write)
  67  *
  68  *  This is the internal write function - a wrapper
  69  *  to tty->ops->write
  70  */
  71 int st_int_write(struct st_data_s *st_gdata,
  72         const unsigned char *data, int count)
  73 {
  74         struct tty_struct *tty;
  75         if (unlikely(st_gdata == NULL || st_gdata->tty == NULL)) {
  76                 pr_err("tty unavailable to perform write");
  77                 return -EINVAL;
  78         }
  79         tty = st_gdata->tty;
  80 #ifdef VERBOSE
  81         print_hex_dump(KERN_DEBUG, "<out<", DUMP_PREFIX_NONE,
  82                 16, 1, data, count, 0);
  83 #endif
  84         return tty->ops->write(tty, data, count);
  85
  86 }
  87
  88 /*
  89  * push the skb received to relevant
  90  * protocol stacks
  91  */
  92 static void st_send_frame(unsigned char chnl_id, struct st_data_s *st_gdata)
  93 {
  94         pr_debug(" %s(prot:%d) ", __func__, chnl_id);
  95
  96         if (unlikely
  97             (st_gdata == NULL || st_gdata->rx_skb == NULL
  98              || st_gdata->is_registered[chnl_id] == false)) {
  99                 pr_err("chnl_id %d not registered, no data to send?",
 100                            chnl_id);
 101                 kfree_skb(st_gdata->rx_skb);
 102                 return;
 103         }
 104         /*
 105          * this cannot fail
 106          * this shouldn't take long
 107          * - should be just skb_queue_tail for the
 108          *   protocol stack driver
 109          */
 110         if (likely(st_gdata->list[chnl_id]->recv != NULL)) {
 111                 if (unlikely
 112                         (st_gdata->list[chnl_id]->recv
 113                         (st_gdata->list[chnl_id]->priv_data, st_gdata->rx_skb)
 114                              != 0)) {
 115                         pr_err(" proto stack %d's ->recv failed", chnl_id);
 116                         kfree_skb(st_gdata->rx_skb);
 117                         return;
 118                 }
 119         } else {
 120                 pr_err(" proto stack %d's ->recv null", chnl_id);
 121                 kfree_skb(st_gdata->rx_skb);
 122         }
 123         return;
 124 }
 125
 126 /*
 127  * st_reg_complete - to call registration complete callbacks
 128  * of all protocol stack drivers
 129  * This function is being called with spin lock held, protocol drivers are
 130  * only expected to complete their waits and do nothing more than that.
 131  */
 132 static void st_reg_complete(struct st_data_s *st_gdata, int err)
 133 {
 134         unsigned char i = 0;
 135         pr_info(" %s ", __func__);
 136         for (i = 0; i < ST_MAX_CHANNELS; i++) {
 137                 if (likely(st_gdata != NULL &&
 138                         st_gdata->is_registered[i] == true &&
 139                                 st_gdata->list[i]->reg_complete_cb != NULL)) {
 140                         st_gdata->list[i]->reg_complete_cb
 141                                 (st_gdata->list[i]->priv_data, err);
 142                         pr_info("protocol %d's cb sent %d\n", i, err);
 143                         if (err) { /* cleanup registered protocol */
 144                                 st_gdata->is_registered[i] = false;
 145                                 if (st_gdata->protos_registered)
 146                                         st_gdata->protos_registered--;
 147                         }
 148                 }
 149         }
 150 }
 151
 152 static inline int st_check_data_len(struct st_data_s *st_gdata,
 153         unsigned char chnl_id, int len)
 154 {
 155         int room = skb_tailroom(st_gdata->rx_skb);
 156
 157         pr_debug("len %d room %d", len, room);
 158
 159         if (!len) {
 160                 /*
 161                  * Received packet has only packet header and
 162                  * has zero length payload. So, ask ST CORE to
 163                  * forward the packet to protocol driver (BT/FM/GPS)
 164                  */
 165                 st_send_frame(chnl_id, st_gdata);
 166
 167         } else if (len > room) {
 168                 /*
 169                  * Received packet's payload length is larger.
 170                  * We can't accommodate it in created skb.
 171                  */
 172                 pr_err("Data length is too large len %d room %d", len,
 173                            room);
 174                 kfree_skb(st_gdata->rx_skb);
 175         } else {
 176                 /*
 177                  * Packet header has non-zero payload length and
 178                  * we have enough space in created skb. Lets read
 179                  * payload data */
 180                 st_gdata->rx_state = ST_W4_DATA;
 181                 st_gdata->rx_count = len;
 182                 return len;
 183         }
 184
 185         /* Change ST state to continue to process next packet */
 186         st_gdata->rx_state = ST_W4_PACKET_TYPE;
 187         st_gdata->rx_skb = NULL;
 188         st_gdata->rx_count = 0;
 189         st_gdata->rx_chnl = 0;
 190
 191         return 0;
 192 }
 193
 194 /*
 195  * st_wakeup_ack - internal function for action when wake-up ack
 196  *      received
 197  */
 198 static inline void st_wakeup_ack(struct st_data_s *st_gdata,
 199         unsigned char cmd)
 200 {
 201         struct sk_buff *waiting_skb;
 202         unsigned long flags = 0;
 203
 204         spin_lock_irqsave(&st_gdata->lock, flags);
 205         /*
 206          * de-Q from waitQ and Q in txQ now that the
 207          * chip is awake
 208          */
 209         while ((waiting_skb = skb_dequeue(&st_gdata->tx_waitq)))
 210                 skb_queue_tail(&st_gdata->txq, waiting_skb);
 211
 212         /* state forwarded to ST LL */
 213         st_ll_sleep_state(st_gdata, (unsigned long)cmd);
 214         spin_unlock_irqrestore(&st_gdata->lock, flags);
 215
 216         /* wake up to send the recently copied skbs from waitQ */
 217         st_tx_wakeup(st_gdata);
 218 }
 219
 220 /*
 221  * st_int_recv - ST's internal receive function.
 222  *      Decodes received RAW data and forwards to corresponding
 223  *      client drivers (Bluetooth,FM,GPS..etc).
 224  *      This can receive various types of packets,
 225  *      HCI-Events, ACL, SCO, 4 types of HCI-LL PM packets
 226  *      CH-8 packets from FM, CH-9 packets from GPS cores.
 227  */
 228 void st_int_recv(void *disc_data,
 229         const unsigned char *data, long count)
 230 {
 231         char *ptr;
 232         struct st_proto_s *proto;
 233         unsigned short payload_len = 0;
 234         int len = 0;
 235         unsigned char type = 0;
 236         unsigned char *plen;
 237         struct st_data_s *st_gdata = (struct st_data_s *)disc_data;
 238         unsigned long flags;
 239
 240         ptr = (char *)data;
 241         /* tty_receive sent null ? */
 242         if (unlikely(ptr == NULL) || (st_gdata == NULL)) {
 243                 pr_err(" received null from TTY ");
 244                 return;
 245         }
 246
 247         pr_debug("count %ld rx_state %ld"
 248                    "rx_count %ld", count, st_gdata->rx_state,
 249                    st_gdata->rx_count);
 250
 251         spin_lock_irqsave(&st_gdata->lock, flags);
 252         /* Decode received bytes here */
 253         while (count) {
 254                 if (st_gdata->rx_count) {
 255                         len = min_t(unsigned int, st_gdata->rx_count, count);
 256                         skb_put_data(st_gdata->rx_skb, ptr, len);
 257                         st_gdata->rx_count -= len;
 258                         count -= len;
 259                         ptr += len;
 260
 261                         if (st_gdata->rx_count)
 262                                 continue;
 263
 264                         /* Check ST RX state machine , where are we? */
 265                         switch (st_gdata->rx_state) {
 266                         /* Waiting for complete packet ? */
 267                         case ST_W4_DATA:
 268                                 pr_debug("Complete pkt received");
 269                                 /*
 270                                  * Ask ST CORE to forward
 271                                  * the packet to protocol driver
 272                                  */
 273                                 st_send_frame(st_gdata->rx_chnl, st_gdata);
 274
 275                                 st_gdata->rx_state = ST_W4_PACKET_TYPE;
 276                                 st_gdata->rx_skb = NULL;
 277                                 continue;
 278                         /* parse the header to know details */
 279                         case ST_W4_HEADER:
 280                                 proto = st_gdata->list[st_gdata->rx_chnl];
 281                                 plen =
 282                                 &st_gdata->rx_skb->data
 283                                 [proto->offset_len_in_hdr];
 284                                 pr_debug("plen pointing to %x\n", *plen);
 285                                 if (proto->len_size == 1) /* 1 byte len field */
 286                                         payload_len = *(unsigned char *)plen;
 287                                 else if (proto->len_size == 2)
 288                                         payload_len =
 289                                         __le16_to_cpu(*(unsigned short *)plen);
 290                                 else
 291                                         pr_info("%s: invalid length "
 292                                         "for id %d\n",
 293                                         __func__, proto->chnl_id);
 294                                 st_check_data_len(st_gdata, proto->chnl_id,
 295                                                 payload_len);
 296                                 pr_debug("off %d, pay len %d\n",
 297                                         proto->offset_len_in_hdr, payload_len);
 298                                 continue;
 299                         }       /* end of switch rx_state */
 300                 }
 301
 302                 /* end of if rx_count */
 303
 304                 /*
 305                  * Check first byte of packet and identify module
 306                  * owner (BT/FM/GPS)
 307                  */
 308                 switch (*ptr) {
 309                 case LL_SLEEP_IND:
 310                 case LL_SLEEP_ACK:
 311                 case LL_WAKE_UP_IND:
 312                         pr_debug("PM packet");
 313                         /*
 314                          * this takes appropriate action based on
 315                          * sleep state received --
 316                          */
 317                         st_ll_sleep_state(st_gdata, *ptr);
 318                         /*
 319                          * if WAKEUP_IND collides copy from waitq to txq
 320                          * and assume chip awake
 321                          */
 322                         spin_unlock_irqrestore(&st_gdata->lock, flags);
 323                         if (st_ll_getstate(st_gdata) == ST_LL_AWAKE)
 324                                 st_wakeup_ack(st_gdata, LL_WAKE_UP_ACK);
 325                         spin_lock_irqsave(&st_gdata->lock, flags);
 326
 327                         ptr++;
 328                         count--;
 329                         continue;
 330                 case LL_WAKE_UP_ACK:
 331                         pr_debug("PM packet");
 332
 333                         spin_unlock_irqrestore(&st_gdata->lock, flags);
 334                         /* wake up ack received */
 335                         st_wakeup_ack(st_gdata, *ptr);
 336                         spin_lock_irqsave(&st_gdata->lock, flags);
 337
 338                         ptr++;
 339                         count--;
 340                         continue;
 341                         /* Unknow packet? */
 342                 default:
 343                         type = *ptr;
 344
 345                         /*
 346                          * Default case means non-HCILL packets,
 347                          * possibilities are packets for:
 348                          * (a) valid protocol -  Supported Protocols within
 349                          *     the ST_MAX_CHANNELS.
 350                          * (b) registered protocol - Checked by
 351                          *     "st_gdata->list[type] == NULL)" are supported
 352                          *     protocols only.
 353                          *  Rules out any invalid protocol and
 354                          *  unregistered protocols with channel ID < 16.
 355                          */
 356
 357                         if ((type >= ST_MAX_CHANNELS) ||
 358                                         (st_gdata->list[type] == NULL)) {
 359                                 pr_err("chip/interface misbehavior: "
 360                                                 "dropping frame starting "
 361                                                 "with 0x%02x\n", type);
 362                                 goto done;
 363                         }
 364
 365                         st_gdata->rx_skb = alloc_skb(
 366                                         st_gdata->list[type]->max_frame_size,
 367                                         GFP_ATOMIC);
 368                         if (st_gdata->rx_skb == NULL) {
 369                                 pr_err("out of memory: dropping\n");
 370                                 goto done;
 371                         }
 372
 373                         skb_reserve(st_gdata->rx_skb,
 374                                         st_gdata->list[type]->reserve);
 375                         /* next 2 required for BT only */
 376                         st_gdata->rx_skb->cb[0] = type; /*pkt_type*/
 377                         st_gdata->rx_skb->cb[1] = 0; /*incoming*/
 378                         st_gdata->rx_chnl = *ptr;
 379                         st_gdata->rx_state = ST_W4_HEADER;
 380                         st_gdata->rx_count = st_gdata->list[type]->hdr_len;
 381                         pr_debug("rx_count %ld\n", st_gdata->rx_count);
 382                 }
 383                 ptr++;
 384                 count--;
 385         }
 386 done:
 387         spin_unlock_irqrestore(&st_gdata->lock, flags);
 388         pr_debug("done %s", __func__);
 389         return;
 390 }
 391
 392 /*
 393  * st_int_dequeue - internal de-Q function.
 394  *      If the previous data set was not written
 395  *      completely, return that skb which has the pending data.
 396  *      In normal cases, return top of txq.
 397  */
 398 static struct sk_buff *st_int_dequeue(struct st_data_s *st_gdata)
 399 {
 400         struct sk_buff *returning_skb;
 401
 402         pr_debug("%s", __func__);
 403         if (st_gdata->tx_skb != NULL) {
 404                 returning_skb = st_gdata->tx_skb;
 405                 st_gdata->tx_skb = NULL;
 406                 return returning_skb;
 407         }
 408         return skb_dequeue(&st_gdata->txq);
 409 }
 410
 411 /*
 412  * st_int_enqueue - internal Q-ing function.
 413  *      Will either Q the skb to txq or the tx_waitq
 414  *      depending on the ST LL state.
 415  *      If the chip is asleep, then Q it onto waitq and
 416  *      wakeup the chip.
 417  *      txq and waitq needs protection since the other contexts
 418  *      may be sending data, waking up chip.
 419  */
 420 static void st_int_enqueue(struct st_data_s *st_gdata, struct sk_buff *skb)
 421 {
 422         unsigned long flags = 0;
 423
 424         pr_debug("%s", __func__);
 425         spin_lock_irqsave(&st_gdata->lock, flags);
 426
 427         switch (st_ll_getstate(st_gdata)) {
 428         case ST_LL_AWAKE:
 429                 pr_debug("ST LL is AWAKE, sending normally");
 430                 skb_queue_tail(&st_gdata->txq, skb);
 431                 break;
 432         case ST_LL_ASLEEP_TO_AWAKE:
 433                 skb_queue_tail(&st_gdata->tx_waitq, skb);
 434                 break;
 435         case ST_LL_AWAKE_TO_ASLEEP:
 436                 pr_err("ST LL is illegal state(%ld),"
 437                            "purging received skb.", st_ll_getstate(st_gdata));
 438                 kfree_skb(skb);
 439                 break;
 440         case ST_LL_ASLEEP:
 441                 skb_queue_tail(&st_gdata->tx_waitq, skb);
 442                 st_ll_wakeup(st_gdata);
 443                 break;
 444         default:
 445                 pr_err("ST LL is illegal state(%ld),"
 446                            "purging received skb.", st_ll_getstate(st_gdata));
 447                 kfree_skb(skb);
 448                 break;
 449         }
 450
 451         spin_unlock_irqrestore(&st_gdata->lock, flags);
 452         pr_debug("done %s", __func__);
 453         return;
 454 }
 455
 456 /*
 457  * internal wakeup function
 458  * called from either
 459  * - TTY layer when write's finished
 460  * - st_write (in context of the protocol stack)
 461  */
 462 static void work_fn_write_wakeup(struct work_struct *work)
 463 {
 464         struct st_data_s *st_gdata = container_of(work, struct st_data_s,
 465                         work_write_wakeup);
 466
 467         st_tx_wakeup((void *)st_gdata);
 468 }
 469 void st_tx_wakeup(struct st_data_s *st_data)
 470 {
 471         struct sk_buff *skb;
 472         unsigned long flags;    /* for irq save flags */
 473         pr_debug("%s", __func__);
 474         /* check for sending & set flag sending here */
 475         if (test_and_set_bit(ST_TX_SENDING, &st_data->tx_state)) {
 476                 pr_debug("ST already sending");
 477                 /* keep sending */
 478                 set_bit(ST_TX_WAKEUP, &st_data->tx_state);
 479                 return;
 480                 /* TX_WAKEUP will be checked in another
 481                  * context
 482                  */
 483         }
 484         do {                    /* come back if st_tx_wakeup is set */
 485                 /* woke-up to write */
 486                 clear_bit(ST_TX_WAKEUP, &st_data->tx_state);
 487                 while ((skb = st_int_dequeue(st_data))) {
 488                         int len;
 489                         spin_lock_irqsave(&st_data->lock, flags);
 490                         /* enable wake-up from TTY */
 491                         set_bit(TTY_DO_WRITE_WAKEUP, &st_data->tty->flags);
 492                         len = st_int_write(st_data, skb->data, skb->len);
 493                         skb_pull(skb, len);
 494                         /* if skb->len = len as expected, skb->len=0 */
 495                         if (skb->len) {
 496                                 /* would be the next skb to be sent */
 497                                 st_data->tx_skb = skb;
 498                                 spin_unlock_irqrestore(&st_data->lock, flags);
 499                                 break;
 500                         }
 501                         kfree_skb(skb);
 502                         spin_unlock_irqrestore(&st_data->lock, flags);
 503                 }
 504                 /* if wake-up is set in another context- restart sending */
 505         } while (test_bit(ST_TX_WAKEUP, &st_data->tx_state));
 506
 507         /* clear flag sending */
 508         clear_bit(ST_TX_SENDING, &st_data->tx_state);
 509 }
 510
 511 /********************************************************************/
 512 /* functions called from ST KIM
 513 */
 514 void kim_st_list_protocols(struct st_data_s *st_gdata, void *buf)
 515 {
 516         seq_printf(buf, "[%d]\nBT=%c\nFM=%c\nGPS=%c\n",
 517                         st_gdata->protos_registered,
 518                         st_gdata->is_registered[0x04] == true ? 'R' : 'U',
 519                         st_gdata->is_registered[0x08] == true ? 'R' : 'U',
 520                         st_gdata->is_registered[0x09] == true ? 'R' : 'U');
 521 }
 522
 523 /********************************************************************/
 524 /*
 525  * functions called from protocol stack drivers
 526  * to be EXPORT-ed
 527  */
 528 long st_register(struct st_proto_s *new_proto)
 529 {
 530         struct st_data_s        *st_gdata;
 531         long err = 0;
 532         unsigned long flags = 0;
 533
 534         st_kim_ref(&st_gdata, 0);
 535         if (st_gdata == NULL || new_proto == NULL || new_proto->recv == NULL
 536             || new_proto->reg_complete_cb == NULL) {
 537                 pr_err("gdata/new_proto/recv or reg_complete_cb not ready");
 538                 return -EINVAL;
 539         }
 540
 541         if (new_proto->chnl_id >= ST_MAX_CHANNELS) {
 542                 pr_err("chnl_id %d not supported", new_proto->chnl_id);
 543                 return -EPROTONOSUPPORT;
 544         }
 545
 546         if (st_gdata->is_registered[new_proto->chnl_id] == true) {
 547                 pr_err("chnl_id %d already registered", new_proto->chnl_id);
 548                 return -EALREADY;
 549         }
 550
 551         /* can be from process context only */
 552         spin_lock_irqsave(&st_gdata->lock, flags);
 553
 554         if (test_bit(ST_REG_IN_PROGRESS, &st_gdata->st_state)) {
 555                 pr_info(" ST_REG_IN_PROGRESS:%d ", new_proto->chnl_id);
 556                 /* fw download in progress */
 557
 558                 add_channel_to_table(st_gdata, new_proto);
 559                 st_gdata->protos_registered++;
 560                 new_proto->write = st_write;
 561
 562                 set_bit(ST_REG_PENDING, &st_gdata->st_state);
 563                 spin_unlock_irqrestore(&st_gdata->lock, flags);
 564                 return -EINPROGRESS;
 565         } else if (st_gdata->protos_registered == ST_EMPTY) {
 566                 pr_info(" chnl_id list empty :%d ", new_proto->chnl_id);
 567                 set_bit(ST_REG_IN_PROGRESS, &st_gdata->st_state);
 568                 st_recv = st_kim_recv;
 569
 570                 /* enable the ST LL - to set default chip state */
 571                 st_ll_enable(st_gdata);
 572
 573                 /* release lock previously held - re-locked below */
 574                 spin_unlock_irqrestore(&st_gdata->lock, flags);
 575
 576                 /*
 577                  * this may take a while to complete
 578                  * since it involves BT fw download
 579                  */
 580                 err = st_kim_start(st_gdata->kim_data);
 581                 if (err != 0) {
 582                         clear_bit(ST_REG_IN_PROGRESS, &st_gdata->st_state);
 583                         if ((st_gdata->protos_registered != ST_EMPTY) &&
 584                             (test_bit(ST_REG_PENDING, &st_gdata->st_state))) {
 585                                 pr_err(" KIM failure complete callback ");
 586                                 spin_lock_irqsave(&st_gdata->lock, flags);
 587                                 st_reg_complete(st_gdata, err);
 588                                 spin_unlock_irqrestore(&st_gdata->lock, flags);
 589                                 clear_bit(ST_REG_PENDING, &st_gdata->st_state);
 590                         }
 591                         return -EINVAL;
 592                 }
 593
 594                 spin_lock_irqsave(&st_gdata->lock, flags);
 595
 596                 clear_bit(ST_REG_IN_PROGRESS, &st_gdata->st_state);
 597                 st_recv = st_int_recv;
 598
 599                 /*
 600                  * this is where all pending registration
 601                  * are signalled to be complete by calling callback functions
 602                  */
 603                 if ((st_gdata->protos_registered != ST_EMPTY) &&
 604                     (test_bit(ST_REG_PENDING, &st_gdata->st_state))) {
 605                         pr_debug(" call reg complete callback ");
 606                         st_reg_complete(st_gdata, 0);
 607                 }
 608                 clear_bit(ST_REG_PENDING, &st_gdata->st_state);
 609
 610                 /*
 611                  * check for already registered once more,
 612                  * since the above check is old
 613                  */
 614                 if (st_gdata->is_registered[new_proto->chnl_id] == true) {
 615                         pr_err(" proto %d already registered ",
 616                                    new_proto->chnl_id);
 617                         spin_unlock_irqrestore(&st_gdata->lock, flags);
 618                         return -EALREADY;
 619                 }
 620
 621                 add_channel_to_table(st_gdata, new_proto);
 622                 st_gdata->protos_registered++;
 623                 new_proto->write = st_write;
 624                 spin_unlock_irqrestore(&st_gdata->lock, flags);
 625                 return err;
 626         }
 627         /* if fw is already downloaded & new stack registers protocol */
 628         else {
 629                 add_channel_to_table(st_gdata, new_proto);
 630                 st_gdata->protos_registered++;
 631                 new_proto->write = st_write;
 632
 633                 /* lock already held before entering else */
 634                 spin_unlock_irqrestore(&st_gdata->lock, flags);
 635                 return err;
 636         }
 637 }
 638 EXPORT_SYMBOL_GPL(st_register);
 639
 640 /*
 641  * to unregister a protocol -
 642  * to be called from protocol stack driver
 643  */
 644 long st_unregister(struct st_proto_s *proto)
 645 {
 646         long err = 0;
 647         unsigned long flags = 0;
 648         struct st_data_s        *st_gdata;
 649
 650         pr_debug("%s: %d ", __func__, proto->chnl_id);
 651
 652         st_kim_ref(&st_gdata, 0);
 653         if (!st_gdata || proto->chnl_id >= ST_MAX_CHANNELS) {
 654                 pr_err(" chnl_id %d not supported", proto->chnl_id);
 655                 return -EPROTONOSUPPORT;
 656         }
 657
 658         spin_lock_irqsave(&st_gdata->lock, flags);
 659
 660         if (st_gdata->is_registered[proto->chnl_id] == false) {
 661                 pr_err(" chnl_id %d not registered", proto->chnl_id);
 662                 spin_unlock_irqrestore(&st_gdata->lock, flags);
 663                 return -EPROTONOSUPPORT;
 664         }
 665
 666         if (st_gdata->protos_registered)
 667                 st_gdata->protos_registered--;
 668
 669         remove_channel_from_table(st_gdata, proto);
 670         spin_unlock_irqrestore(&st_gdata->lock, flags);
 671
 672         if ((st_gdata->protos_registered == ST_EMPTY) &&
 673             (!test_bit(ST_REG_PENDING, &st_gdata->st_state))) {
 674                 pr_info(" all chnl_ids unregistered ");
 675
 676                 /* stop traffic on tty */
 677                 if (st_gdata->tty) {
 678                         tty_ldisc_flush(st_gdata->tty);
 679                         stop_tty(st_gdata->tty);
 680                 }
 681
 682                 /* all chnl_ids now unregistered */
 683                 st_kim_stop(st_gdata->kim_data);
 684                 /* disable ST LL */
 685                 st_ll_disable(st_gdata);
 686         }
 687         return err;
 688 }
 689
 690 /*
 691  * called in protocol stack drivers
 692  * via the write function pointer
 693  */
 694 long st_write(struct sk_buff *skb)
 695 {
 696         struct st_data_s *st_gdata;
 697         long len;
 698
 699         st_kim_ref(&st_gdata, 0);
 700         if (unlikely(skb == NULL || st_gdata == NULL
 701                 || st_gdata->tty == NULL)) {
 702                 pr_err("data/tty unavailable to perform write");
 703                 return -EINVAL;
 704         }
 705
 706         pr_debug("%d to be written", skb->len);
 707         len = skb->len;
 708
 709         /* st_ll to decide where to enqueue the skb */
 710         st_int_enqueue(st_gdata, skb);
 711         /* wake up */
 712         st_tx_wakeup(st_gdata);
 713
 714         /* return number of bytes written */
 715         return len;
 716 }
 717
 718 /* for protocols making use of shared transport */
 719 EXPORT_SYMBOL_GPL(st_unregister);
 720
 721 /********************************************************************/
 722 /*
 723  * functions called from TTY layer
 724  */
 725 static int st_tty_open(struct tty_struct *tty)
 726 {
 727         struct st_data_s *st_gdata;
 728         pr_info("%s ", __func__);
 729
 730         st_kim_ref(&st_gdata, 0);
 731         st_gdata->tty = tty;
 732         tty->disc_data = st_gdata;
 733
 734         /* don't do an wakeup for now */
 735         clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
 736
 737         /* mem already allocated
 738          */
 739         tty->receive_room = 65536;
 740         /* Flush any pending characters in the driver and discipline. */
 741         tty_ldisc_flush(tty);
 742         tty_driver_flush_buffer(tty);
 743         /*
 744          * signal to UIM via KIM that -
 745          * installation of N_TI_WL ldisc is complete
 746          */
 747         st_kim_complete(st_gdata->kim_data);
 748         pr_debug("done %s", __func__);
 749
 750         return 0;
 751 }
 752
 753 static void st_tty_close(struct tty_struct *tty)
 754 {
 755         unsigned char i;
 756         unsigned long flags;
 757         struct  st_data_s *st_gdata = tty->disc_data;
 758
 759         pr_info("%s ", __func__);
 760
 761         /*
 762          * TODO:
 763          * if a protocol has been registered & line discipline
 764          * un-installed for some reason - what should be done ?
 765          */
 766         spin_lock_irqsave(&st_gdata->lock, flags);
 767         for (i = ST_BT; i < ST_MAX_CHANNELS; i++) {
 768                 if (st_gdata->is_registered[i] == true)
 769                         pr_err("%d not un-registered", i);
 770                 st_gdata->list[i] = NULL;
 771                 st_gdata->is_registered[i] = false;
 772         }
 773         st_gdata->protos_registered = 0;
 774         spin_unlock_irqrestore(&st_gdata->lock, flags);
 775         /*
 776          * signal to UIM via KIM that -
 777          * N_TI_WL ldisc is un-installed
 778          */
 779         st_kim_complete(st_gdata->kim_data);
 780         st_gdata->tty = NULL;
 781         /* Flush any pending characters in the driver and discipline. */
 782         tty_ldisc_flush(tty);
 783         tty_driver_flush_buffer(tty);
 784
 785         spin_lock_irqsave(&st_gdata->lock, flags);
 786         /* empty out txq and tx_waitq */
 787         skb_queue_purge(&st_gdata->txq);
 788         skb_queue_purge(&st_gdata->tx_waitq);
 789         /* reset the TTY Rx states of ST */
 790         st_gdata->rx_count = 0;
 791         st_gdata->rx_state = ST_W4_PACKET_TYPE;
 792         kfree_skb(st_gdata->rx_skb);
 793         st_gdata->rx_skb = NULL;
 794         spin_unlock_irqrestore(&st_gdata->lock, flags);
 795
 796         pr_debug("%s: done ", __func__);
 797 }
 798
 799 static void st_tty_receive(struct tty_struct *tty, const unsigned char *data,
 800                            const char *tty_flags, int count)
 801 {
 802 #ifdef VERBOSE
 803         print_hex_dump(KERN_DEBUG, ">in>", DUMP_PREFIX_NONE,
 804                 16, 1, data, count, 0);
 805 #endif
 806
 807         /*
 808          * if fw download is in progress then route incoming data
 809          * to KIM for validation
 810          */
 811         st_recv(tty->disc_data, data, count);
 812         pr_debug("done %s", __func__);
 813 }
 814
 815 /*
 816  * wake-up function called in from the TTY layer
 817  * inside the internal wakeup function will be called
 818  */
 819 static void st_tty_wakeup(struct tty_struct *tty)
 820 {
 821         struct  st_data_s *st_gdata = tty->disc_data;
 822         pr_debug("%s ", __func__);
 823         /* don't do an wakeup for now */
 824         clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
 825
 826         /*
 827          * schedule the internal wakeup instead of calling directly to
 828          * avoid lockup (port->lock needed in tty->ops->write is
 829          * already taken here
 830          */
 831         schedule_work(&st_gdata->work_write_wakeup);
 832 }
 833
 834 static void st_tty_flush_buffer(struct tty_struct *tty)
 835 {
 836         struct  st_data_s *st_gdata = tty->disc_data;
 837         pr_debug("%s ", __func__);
 838
 839         kfree_skb(st_gdata->tx_skb);
 840         st_gdata->tx_skb = NULL;
 841
 842         tty_driver_flush_buffer(tty);
 843         return;
 844 }
 845
 846 static struct tty_ldisc_ops st_ldisc_ops = {
 847         .num = N_TI_WL,
 848         .name = "n_st",
 849         .open = st_tty_open,
 850         .close = st_tty_close,
 851         .receive_buf = st_tty_receive,
 852         .write_wakeup = st_tty_wakeup,
 853         .flush_buffer = st_tty_flush_buffer,
 854         .owner = THIS_MODULE
 855 };
 856
 857 /********************************************************************/
 858 int st_core_init(struct st_data_s **core_data)
 859 {
 860         struct st_data_s *st_gdata;
 861         long err;
 862
 863         err = tty_register_ldisc(&st_ldisc_ops);
 864         if (err) {
 865                 pr_err("error registering %d line discipline %ld",
 866                            N_TI_WL, err);
 867                 return err;
 868         }
 869         pr_debug("registered n_shared line discipline");
 870
 871         st_gdata = kzalloc(sizeof(struct st_data_s), GFP_KERNEL);
 872         if (!st_gdata) {
 873                 pr_err("memory allocation failed");
 874                 err = -ENOMEM;
 875                 goto err_unreg_ldisc;
 876         }
 877
 878         /* Initialize ST TxQ and Tx waitQ queue head. All BT/FM/GPS module skb's
 879          * will be pushed in this queue for actual transmission.
 880          */
 881         skb_queue_head_init(&st_gdata->txq);
 882         skb_queue_head_init(&st_gdata->tx_waitq);
 883
 884         /* Locking used in st_int_enqueue() to avoid multiple execution */
 885         spin_lock_init(&st_gdata->lock);
 886
 887         err = st_ll_init(st_gdata);
 888         if (err) {
 889                 pr_err("error during st_ll initialization(%ld)", err);
 890                 goto err_free_gdata;
 891         }
 892
 893         INIT_WORK(&st_gdata->work_write_wakeup, work_fn_write_wakeup);
 894
 895         *core_data = st_gdata;
 896         return 0;
 897 err_free_gdata:
 898         kfree(st_gdata);
 899 err_unreg_ldisc:
 900         tty_unregister_ldisc(&st_ldisc_ops);
 901         return err;
 902 }
 903
 904 void st_core_exit(struct st_data_s *st_gdata)
 905 {
 906         long err;
 907         /* internal module cleanup */
 908         err = st_ll_deinit(st_gdata);
 909         if (err)
 910                 pr_err("error during deinit of ST LL %ld", err);
 911
 912         if (st_gdata != NULL) {
 913                 /* Free ST Tx Qs and skbs */
 914                 skb_queue_purge(&st_gdata->txq);
 915                 skb_queue_purge(&st_gdata->tx_waitq);
 916                 kfree_skb(st_gdata->rx_skb);
 917                 kfree_skb(st_gdata->tx_skb);
 918                 /* TTY ldisc cleanup */
 919                 tty_unregister_ldisc(&st_ldisc_ops);
 920                 /* free the global data pointer */
 921                 kfree(st_gdata);
 922         }
 923 }