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 <pavan_savoy@ti.com>
   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 #include <linux/netdevice.h>
  19
  20 extern void st_kim_recv(void *, const unsigned char *, long);
  21 void st_int_recv(void *, const unsigned char *, long);
  22 /*
  23  * function pointer pointing to either,
  24  * st_kim_recv during registration to receive fw download responses
  25  * st_int_recv after registration to receive proto stack responses
  26  */
  27 static void (*st_recv) (void *, const unsigned char *, long);
  28
  29 /********************************************************************/
  30 static void add_channel_to_table(struct st_data_s *st_gdata,
  31                 struct st_proto_s *new_proto)
  32 {
  33         pr_info("%s: id %d\n", __func__, new_proto->chnl_id);
  34         /* list now has the channel id as index itself */
  35         st_gdata->list[new_proto->chnl_id] = new_proto;
  36         st_gdata->is_registered[new_proto->chnl_id] = true;
  37 }
  38
  39 static void remove_channel_from_table(struct st_data_s *st_gdata,
  40                 struct st_proto_s *proto)
  41 {
  42         pr_info("%s: id %d\n", __func__, proto->chnl_id);
  43 /*      st_gdata->list[proto->chnl_id] = NULL; */
  44         st_gdata->is_registered[proto->chnl_id] = false;
  45 }
  46
  47 /*
  48  * called from KIM during firmware download.
  49  *
  50  * This is a wrapper function to tty->ops->write_room.
  51  * It returns number of free space available in
  52  * uart tx buffer.
  53  */
  54 int st_get_uart_wr_room(struct st_data_s *st_gdata)
  55 {
  56         struct tty_struct *tty;
  57         if (unlikely(st_gdata == NULL || st_gdata->tty == NULL)) {
  58                 pr_err("tty unavailable to perform write");
  59                 return -1;
  60         }
  61         tty = st_gdata->tty;
  62         return tty->ops->write_room(tty);
  63 }
  64
  65 /*
  66  * can be called in from
  67  * -- KIM (during fw download)
  68  * -- ST Core (during st_write)
  69  *
  70  *  This is the internal write function - a wrapper
  71  *  to tty->ops->write
  72  */
  73 int st_int_write(struct st_data_s *st_gdata,
  74         const unsigned char *data, int count)
  75 {
  76         struct tty_struct *tty;
  77         if (unlikely(st_gdata == NULL || st_gdata->tty == NULL)) {
  78                 pr_err("tty unavailable to perform write");
  79                 return -EINVAL;
  80         }
  81         tty = st_gdata->tty;
  82 #ifdef VERBOSE
  83         print_hex_dump(KERN_DEBUG, "<out<", DUMP_PREFIX_NONE,
  84                 16, 1, data, count, 0);
  85 #endif
  86         return tty->ops->write(tty, data, count);
  87
  88 }
  89
  90 /*
  91  * push the skb received to relevant
  92  * protocol stacks
  93  */
  94 static void st_send_frame(unsigned char chnl_id, struct st_data_s *st_gdata)
  95 {
  96         pr_debug(" %s(prot:%d) ", __func__, chnl_id);
  97
  98         if (unlikely
  99             (st_gdata == NULL || st_gdata->rx_skb == NULL
 100              || st_gdata->is_registered[chnl_id] == false)) {
 101                 pr_err("chnl_id %d not registered, no data to send?",
 102                            chnl_id);
 103                 kfree_skb(st_gdata->rx_skb);
 104                 return;
 105         }
 106         /*
 107          * this cannot fail
 108          * this shouldn't take long
 109          * - should be just skb_queue_tail for the
 110          *   protocol stack driver
 111          */
 112         if (likely(st_gdata->list[chnl_id]->recv != NULL)) {
 113                 if (unlikely
 114                         (st_gdata->list[chnl_id]->recv
 115                         (st_gdata->list[chnl_id]->priv_data, st_gdata->rx_skb)
 116                              != 0)) {
 117                         pr_err(" proto stack %d's ->recv failed", chnl_id);
 118                         kfree_skb(st_gdata->rx_skb);
 119                         return;
 120                 }
 121         } else {
 122                 pr_err(" proto stack %d's ->recv null", chnl_id);
 123                 kfree_skb(st_gdata->rx_skb);
 124         }
 125         return;
 126 }
 127
 128 /*
 129  * st_reg_complete - to call registration complete callbacks
 130  * of all protocol stack drivers
 131  * This function is being called with spin lock held, protocol drivers are
 132  * only expected to complete their waits and do nothing more than that.
 133  */
 134 static void st_reg_complete(struct st_data_s *st_gdata, int err)
 135 {
 136         unsigned char i = 0;
 137         pr_info(" %s ", __func__);
 138         for (i = 0; i < ST_MAX_CHANNELS; i++) {
 139                 if (likely(st_gdata != NULL &&
 140                         st_gdata->is_registered[i] == true &&
 141                                 st_gdata->list[i]->reg_complete_cb != NULL)) {
 142                         st_gdata->list[i]->reg_complete_cb
 143                                 (st_gdata->list[i]->priv_data, err);
 144                         pr_info("protocol %d's cb sent %d\n", i, err);
 145                         if (err) { /* cleanup registered protocol */
 146                                 st_gdata->is_registered[i] = false;
 147                                 if (st_gdata->protos_registered)
 148                                         st_gdata->protos_registered--;
 149                         }
 150                 }
 151         }
 152 }
 153
 154 static inline int st_check_data_len(struct st_data_s *st_gdata,
 155         unsigned char chnl_id, int len)
 156 {
 157         int room = skb_tailroom(st_gdata->rx_skb);
 158
 159         pr_debug("len %d room %d", len, room);
 160
 161         if (!len) {
 162                 /*
 163                  * Received packet has only packet header and
 164                  * has zero length payload. So, ask ST CORE to
 165                  * forward the packet to protocol driver (BT/FM/GPS)
 166                  */
 167                 st_send_frame(chnl_id, st_gdata);
 168
 169         } else if (len > room) {
 170                 /*
 171                  * Received packet's payload length is larger.
 172                  * We can't accommodate it in created skb.
 173                  */
 174                 pr_err("Data length is too large len %d room %d", len,
 175                            room);
 176                 kfree_skb(st_gdata->rx_skb);
 177         } else {
 178                 /*
 179                  * Packet header has non-zero payload length and
 180                  * we have enough space in created skb. Lets read
 181                  * payload data */
 182                 st_gdata->rx_state = ST_W4_DATA;
 183                 st_gdata->rx_count = len;
 184                 return len;
 185         }
 186
 187         /* Change ST state to continue to process next packet */
 188         st_gdata->rx_state = ST_W4_PACKET_TYPE;
 189         st_gdata->rx_skb = NULL;
 190         st_gdata->rx_count = 0;
 191         st_gdata->rx_chnl = 0;
 192
 193         return 0;
 194 }
 195
 196 /*
 197  * st_wakeup_ack - internal function for action when wake-up ack
 198  *      received
 199  */
 200 static inline void st_wakeup_ack(struct st_data_s *st_gdata,
 201         unsigned char cmd)
 202 {
 203         struct sk_buff *waiting_skb;
 204         unsigned long flags = 0;
 205
 206         spin_lock_irqsave(&st_gdata->lock, flags);
 207         /*
 208          * de-Q from waitQ and Q in txQ now that the
 209          * chip is awake
 210          */
 211         while ((waiting_skb = skb_dequeue(&st_gdata->tx_waitq)))
 212                 skb_queue_tail(&st_gdata->txq, waiting_skb);
 213
 214         /* state forwarded to ST LL */
 215         st_ll_sleep_state(st_gdata, (unsigned long)cmd);
 216         spin_unlock_irqrestore(&st_gdata->lock, flags);
 217
 218         /* wake up to send the recently copied skbs from waitQ */
 219         st_tx_wakeup(st_gdata);
 220 }
 221
 222 /*
 223  * st_int_recv - ST's internal receive function.
 224  *      Decodes received RAW data and forwards to corresponding
 225  *      client drivers (Bluetooth,FM,GPS..etc).
 226  *      This can receive various types of packets,
 227  *      HCI-Events, ACL, SCO, 4 types of HCI-LL PM packets
 228  *      CH-8 packets from FM, CH-9 packets from GPS cores.
 229  */
 230 void st_int_recv(void *disc_data,
 231         const unsigned char *data, long count)
 232 {
 233         char *ptr;
 234         struct st_proto_s *proto;
 235         unsigned short payload_len = 0;
 236         int len = 0;
 237         unsigned char type = 0;
 238         unsigned char *plen;
 239         struct st_data_s *st_gdata = (struct st_data_s *)disc_data;
 240         unsigned long flags;
 241
 242         ptr = (char *)data;
 243         /* tty_receive sent null ? */
 244         if (unlikely(ptr == NULL) || (st_gdata == NULL)) {
 245                 pr_err(" received null from TTY ");
 246                 return;
 247         }
 248
 249         pr_debug("count %ld rx_state %ld"
 250                    "rx_count %ld", count, st_gdata->rx_state,
 251                    st_gdata->rx_count);
 252
 253         spin_lock_irqsave(&st_gdata->lock, flags);
 254         /* Decode received bytes here */
 255         while (count) {
 256                 if (st_gdata->rx_count) {
 257                         len = min_t(unsigned int, st_gdata->rx_count, count);
 258                         skb_put_data(st_gdata->rx_skb, ptr, len);
 259                         st_gdata->rx_count -= len;
 260                         count -= len;
 261                         ptr += len;
 262
 263                         if (st_gdata->rx_count)
 264                                 continue;
 265
 266                         /* Check ST RX state machine , where are we? */
 267                         switch (st_gdata->rx_state) {
 268                         /* Waiting for complete packet ? */
 269                         case ST_W4_DATA:
 270                                 pr_debug("Complete pkt received");
 271                                 /*
 272                                  * Ask ST CORE to forward
 273                                  * the packet to protocol driver
 274                                  */
 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
 306                 /*
 307                  * Check first byte of packet and identify module
 308                  * owner (BT/FM/GPS)
 309                  */
 310                 switch (*ptr) {
 311                 case LL_SLEEP_IND:
 312                 case LL_SLEEP_ACK:
 313                 case LL_WAKE_UP_IND:
 314                         pr_debug("PM packet");
 315                         /*
 316                          * this takes appropriate action based on
 317                          * sleep state received --
 318                          */
 319                         st_ll_sleep_state(st_gdata, *ptr);
 320                         /*
 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
 347                         /*
 348                          * Default case means non-HCILL packets,
 349                          * possibilities are packets for:
 350                          * (a) valid protocol -  Supported Protocols within
 351                          *     the ST_MAX_CHANNELS.
 352                          * (b) registered protocol - Checked by
 353                          *     "st_gdata->list[type] == NULL)" are supported
 354                          *     protocols only.
 355                          *  Rules out any invalid protocol and
 356                          *  unregistered protocols with channel ID < 16.
 357                          */
 358
 359                         if ((type >= ST_MAX_CHANNELS) ||
 360                                         (st_gdata->list[type] == NULL)) {
 361                                 pr_err("chip/interface misbehavior: "
 362                                                 "dropping frame starting "
 363                                                 "with 0x%02x\n", type);
 364                                 goto done;
 365                         }
 366
 367                         st_gdata->rx_skb = alloc_skb(
 368                                         st_gdata->list[type]->max_frame_size,
 369                                         GFP_ATOMIC);
 370                         if (st_gdata->rx_skb == NULL) {
 371                                 pr_err("out of memory: dropping\n");
 372                                 goto done;
 373                         }
 374
 375                         skb_reserve(st_gdata->rx_skb,
 376                                         st_gdata->list[type]->reserve);
 377                         /* next 2 required for BT only */
 378                         st_gdata->rx_skb->cb[0] = type; /*pkt_type*/
 379                         st_gdata->rx_skb->cb[1] = 0; /*incoming*/
 380                         st_gdata->rx_chnl = *ptr;
 381                         st_gdata->rx_state = ST_W4_HEADER;
 382                         st_gdata->rx_count = st_gdata->list[type]->hdr_len;
 383                         pr_debug("rx_count %ld\n", st_gdata->rx_count);
 384                 };
 385                 ptr++;
 386                 count--;
 387         }
 388 done:
 389         spin_unlock_irqrestore(&st_gdata->lock, flags);
 390         pr_debug("done %s", __func__);
 391         return;
 392 }
 393
 394 /*
 395  * st_int_dequeue - internal de-Q function.
 396  *      If the previous data set was not written
 397  *      completely, return that skb which has the pending data.
 398  *      In normal cases, return top of txq.
 399  */
 400 static struct sk_buff *st_int_dequeue(struct st_data_s *st_gdata)
 401 {
 402         struct sk_buff *returning_skb;
 403
 404         pr_debug("%s", __func__);
 405         if (st_gdata->tx_skb != NULL) {
 406                 returning_skb = st_gdata->tx_skb;
 407                 st_gdata->tx_skb = NULL;
 408                 return returning_skb;
 409         }
 410         return skb_dequeue(&st_gdata->txq);
 411 }
 412
 413 /*
 414  * st_int_enqueue - internal Q-ing function.
 415  *      Will either Q the skb to txq or the tx_waitq
 416  *      depending on the ST LL state.
 417  *      If the chip is asleep, then Q it onto waitq and
 418  *      wakeup the chip.
 419  *      txq and waitq needs protection since the other contexts
 420  *      may be sending data, waking up chip.
 421  */
 422 static void st_int_enqueue(struct st_data_s *st_gdata, struct sk_buff *skb)
 423 {
 424         unsigned long flags = 0;
 425
 426         pr_debug("%s", __func__);
 427         spin_lock_irqsave(&st_gdata->lock, flags);
 428
 429         switch (st_ll_getstate(st_gdata)) {
 430         case ST_LL_AWAKE:
 431                 pr_debug("ST LL is AWAKE, sending normally");
 432                 skb_queue_tail(&st_gdata->txq, skb);
 433                 break;
 434         case ST_LL_ASLEEP_TO_AWAKE:
 435                 skb_queue_tail(&st_gdata->tx_waitq, skb);
 436                 break;
 437         case ST_LL_AWAKE_TO_ASLEEP:
 438                 pr_err("ST LL is illegal state(%ld),"
 439                            "purging received skb.", st_ll_getstate(st_gdata));
 440                 dev_kfree_skb_irq(skb);
 441                 break;
 442         case ST_LL_ASLEEP:
 443                 skb_queue_tail(&st_gdata->tx_waitq, skb);
 444                 st_ll_wakeup(st_gdata);
 445                 break;
 446         default:
 447                 pr_err("ST LL is illegal state(%ld),"
 448                            "purging received skb.", st_ll_getstate(st_gdata));
 449                 dev_kfree_skb_irq(skb);
 450                 break;
 451         }
 452
 453         spin_unlock_irqrestore(&st_gdata->lock, flags);
 454         pr_debug("done %s", __func__);
 455         return;
 456 }
 457
 458 /*
 459  * internal wakeup function
 460  * called from either
 461  * - TTY layer when write's finished
 462  * - st_write (in context of the protocol stack)
 463  */
 464 static void work_fn_write_wakeup(struct work_struct *work)
 465 {
 466         struct st_data_s *st_gdata = container_of(work, struct st_data_s,
 467                         work_write_wakeup);
 468
 469         st_tx_wakeup((void *)st_gdata);
 470 }
 471 void st_tx_wakeup(struct st_data_s *st_data)
 472 {
 473         struct sk_buff *skb;
 474         unsigned long flags;    /* for irq save flags */
 475         pr_debug("%s", __func__);
 476         /* check for sending & set flag sending here */
 477         if (test_and_set_bit(ST_TX_SENDING, &st_data->tx_state)) {
 478                 pr_debug("ST already sending");
 479                 /* keep sending */
 480                 set_bit(ST_TX_WAKEUP, &st_data->tx_state);
 481                 return;
 482                 /* TX_WAKEUP will be checked in another
 483                  * context
 484                  */
 485         }
 486         do {                    /* come back if st_tx_wakeup is set */
 487                 /* woke-up to write */
 488                 clear_bit(ST_TX_WAKEUP, &st_data->tx_state);
 489                 while ((skb = st_int_dequeue(st_data))) {
 490                         int len;
 491                         spin_lock_irqsave(&st_data->lock, flags);
 492                         /* enable wake-up from TTY */
 493                         set_bit(TTY_DO_WRITE_WAKEUP, &st_data->tty->flags);
 494                         len = st_int_write(st_data, skb->data, skb->len);
 495                         skb_pull(skb, len);
 496                         /* if skb->len = len as expected, skb->len=0 */
 497                         if (skb->len) {
 498                                 /* would be the next skb to be sent */
 499                                 st_data->tx_skb = skb;
 500                                 spin_unlock_irqrestore(&st_data->lock, flags);
 501                                 break;
 502                         }
 503                         dev_kfree_skb_irq(skb);
 504                         spin_unlock_irqrestore(&st_data->lock, flags);
 505                 }
 506                 /* if wake-up is set in another context- restart sending */
 507         } while (test_bit(ST_TX_WAKEUP, &st_data->tx_state));
 508
 509         /* clear flag sending */
 510         clear_bit(ST_TX_SENDING, &st_data->tx_state);
 511 }
 512
 513 /********************************************************************/
 514 /* functions called from ST KIM
 515 */
 516 void kim_st_list_protocols(struct st_data_s *st_gdata, void *buf)
 517 {
 518         seq_printf(buf, "[%d]\nBT=%c\nFM=%c\nGPS=%c\n",
 519                         st_gdata->protos_registered,
 520                         st_gdata->is_registered[0x04] == true ? 'R' : 'U',
 521                         st_gdata->is_registered[0x08] == true ? 'R' : 'U',
 522                         st_gdata->is_registered[0x09] == true ? 'R' : 'U');
 523 }
 524
 525 /********************************************************************/
 526 /*
 527  * functions called from protocol stack drivers
 528  * to be EXPORT-ed
 529  */
 530 long st_register(struct st_proto_s *new_proto)
 531 {
 532         struct st_data_s        *st_gdata;
 533         long err = 0;
 534         unsigned long flags = 0;
 535
 536         st_kim_ref(&st_gdata, 0);
 537         if (st_gdata == NULL || new_proto == NULL || new_proto->recv == NULL
 538             || new_proto->reg_complete_cb == NULL) {
 539                 pr_err("gdata/new_proto/recv or reg_complete_cb not ready");
 540                 return -EINVAL;
 541         }
 542
 543         if (new_proto->chnl_id >= ST_MAX_CHANNELS) {
 544                 pr_err("chnl_id %d not supported", new_proto->chnl_id);
 545                 return -EPROTONOSUPPORT;
 546         }
 547
 548         if (st_gdata->is_registered[new_proto->chnl_id] == true) {
 549                 pr_err("chnl_id %d already registered", new_proto->chnl_id);
 550                 return -EALREADY;
 551         }
 552
 553         /* can be from process context only */
 554         spin_lock_irqsave(&st_gdata->lock, flags);
 555
 556         if (test_bit(ST_REG_IN_PROGRESS, &st_gdata->st_state)) {
 557                 pr_info(" ST_REG_IN_PROGRESS:%d ", new_proto->chnl_id);
 558                 /* fw download in progress */
 559
 560                 add_channel_to_table(st_gdata, new_proto);
 561                 st_gdata->protos_registered++;
 562                 new_proto->write = st_write;
 563
 564                 set_bit(ST_REG_PENDING, &st_gdata->st_state);
 565                 spin_unlock_irqrestore(&st_gdata->lock, flags);
 566                 return -EINPROGRESS;
 567         } else if (st_gdata->protos_registered == ST_EMPTY) {
 568                 pr_info(" chnl_id list empty :%d ", new_proto->chnl_id);
 569                 set_bit(ST_REG_IN_PROGRESS, &st_gdata->st_state);
 570                 st_recv = st_kim_recv;
 571
 572                 /* enable the ST LL - to set default chip state */
 573                 st_ll_enable(st_gdata);
 574
 575                 /* release lock previously held - re-locked below */
 576                 spin_unlock_irqrestore(&st_gdata->lock, flags);
 577
 578                 /*
 579                  * this may take a while to complete
 580                  * since it involves BT fw download
 581                  */
 582                 err = st_kim_start(st_gdata->kim_data);
 583                 if (err != 0) {
 584                         clear_bit(ST_REG_IN_PROGRESS, &st_gdata->st_state);
 585                         if ((st_gdata->protos_registered != ST_EMPTY) &&
 586                             (test_bit(ST_REG_PENDING, &st_gdata->st_state))) {
 587                                 pr_err(" KIM failure complete callback ");
 588                                 spin_lock_irqsave(&st_gdata->lock, flags);
 589                                 st_reg_complete(st_gdata, err);
 590                                 spin_unlock_irqrestore(&st_gdata->lock, flags);
 591                                 clear_bit(ST_REG_PENDING, &st_gdata->st_state);
 592                         }
 593                         return -EINVAL;
 594                 }
 595
 596                 spin_lock_irqsave(&st_gdata->lock, flags);
 597
 598                 clear_bit(ST_REG_IN_PROGRESS, &st_gdata->st_state);
 599                 st_recv = st_int_recv;
 600
 601                 /*
 602                  * this is where all pending registration
 603                  * are signalled to be complete by calling callback functions
 604                  */
 605                 if ((st_gdata->protos_registered != ST_EMPTY) &&
 606                     (test_bit(ST_REG_PENDING, &st_gdata->st_state))) {
 607                         pr_debug(" call reg complete callback ");
 608                         st_reg_complete(st_gdata, 0);
 609                 }
 610                 clear_bit(ST_REG_PENDING, &st_gdata->st_state);
 611
 612                 /*
 613                  * check for already registered once more,
 614                  * since the above check is old
 615                  */
 616                 if (st_gdata->is_registered[new_proto->chnl_id] == true) {
 617                         pr_err(" proto %d already registered ",
 618                                    new_proto->chnl_id);
 619                         spin_unlock_irqrestore(&st_gdata->lock, flags);
 620                         return -EALREADY;
 621                 }
 622
 623                 add_channel_to_table(st_gdata, new_proto);
 624                 st_gdata->protos_registered++;
 625                 new_proto->write = st_write;
 626                 spin_unlock_irqrestore(&st_gdata->lock, flags);
 627                 return err;
 628         }
 629         /* if fw is already downloaded & new stack registers protocol */
 630         else {
 631                 add_channel_to_table(st_gdata, new_proto);
 632                 st_gdata->protos_registered++;
 633                 new_proto->write = st_write;
 634
 635                 /* lock already held before entering else */
 636                 spin_unlock_irqrestore(&st_gdata->lock, flags);
 637                 return err;
 638         }
 639 }
 640 EXPORT_SYMBOL_GPL(st_register);
 641
 642 /*
 643  * to unregister a protocol -
 644  * to be called from protocol stack driver
 645  */
 646 long st_unregister(struct st_proto_s *proto)
 647 {
 648         long err = 0;
 649         unsigned long flags = 0;
 650         struct st_data_s        *st_gdata;
 651
 652         pr_debug("%s: %d ", __func__, proto->chnl_id);
 653
 654         st_kim_ref(&st_gdata, 0);
 655         if (!st_gdata || proto->chnl_id >= ST_MAX_CHANNELS) {
 656                 pr_err(" chnl_id %d not supported", proto->chnl_id);
 657                 return -EPROTONOSUPPORT;
 658         }
 659
 660         spin_lock_irqsave(&st_gdata->lock, flags);
 661
 662         if (st_gdata->is_registered[proto->chnl_id] == false) {
 663                 pr_err(" chnl_id %d not registered", proto->chnl_id);
 664                 spin_unlock_irqrestore(&st_gdata->lock, flags);
 665                 return -EPROTONOSUPPORT;
 666         }
 667
 668         if (st_gdata->protos_registered)
 669                 st_gdata->protos_registered--;
 670
 671         remove_channel_from_table(st_gdata, proto);
 672         spin_unlock_irqrestore(&st_gdata->lock, flags);
 673
 674         if ((st_gdata->protos_registered == ST_EMPTY) &&
 675             (!test_bit(ST_REG_PENDING, &st_gdata->st_state))) {
 676                 pr_info(" all chnl_ids unregistered ");
 677
 678                 /* stop traffic on tty */
 679                 if (st_gdata->tty) {
 680                         tty_ldisc_flush(st_gdata->tty);
 681                         stop_tty(st_gdata->tty);
 682                 }
 683
 684                 /* all chnl_ids now unregistered */
 685                 st_kim_stop(st_gdata->kim_data);
 686                 /* disable ST LL */
 687                 st_ll_disable(st_gdata);
 688         }
 689         return err;
 690 }
 691
 692 /*
 693  * called in protocol stack drivers
 694  * via the write function pointer
 695  */
 696 long st_write(struct sk_buff *skb)
 697 {
 698         struct st_data_s *st_gdata;
 699         long len;
 700
 701         st_kim_ref(&st_gdata, 0);
 702         if (unlikely(skb == NULL || st_gdata == NULL
 703                 || st_gdata->tty == NULL)) {
 704                 pr_err("data/tty unavailable to perform write");
 705                 return -EINVAL;
 706         }
 707
 708         pr_debug("%d to be written", skb->len);
 709         len = skb->len;
 710
 711         /* st_ll to decide where to enqueue the skb */
 712         st_int_enqueue(st_gdata, skb);
 713         /* wake up */
 714         st_tx_wakeup(st_gdata);
 715
 716         /* return number of bytes written */
 717         return len;
 718 }
 719
 720 /* for protocols making use of shared transport */
 721 EXPORT_SYMBOL_GPL(st_unregister);
 722
 723 /********************************************************************/
 724 /*
 725  * functions called from TTY layer
 726  */
 727 static int st_tty_open(struct tty_struct *tty)
 728 {
 729         struct st_data_s *st_gdata;
 730         pr_info("%s ", __func__);
 731
 732         st_kim_ref(&st_gdata, 0);
 733         st_gdata->tty = tty;
 734         tty->disc_data = st_gdata;
 735
 736         /* don't do an wakeup for now */
 737         clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
 738
 739         /* mem already allocated
 740          */
 741         tty->receive_room = 65536;
 742         /* Flush any pending characters in the driver and discipline. */
 743         tty_ldisc_flush(tty);
 744         tty_driver_flush_buffer(tty);
 745         /*
 746          * signal to UIM via KIM that -
 747          * installation of N_TI_WL ldisc is complete
 748          */
 749         st_kim_complete(st_gdata->kim_data);
 750         pr_debug("done %s", __func__);
 751
 752         return 0;
 753 }
 754
 755 static void st_tty_close(struct tty_struct *tty)
 756 {
 757         unsigned char i;
 758         unsigned long flags;
 759         struct  st_data_s *st_gdata = tty->disc_data;
 760
 761         pr_info("%s ", __func__);
 762
 763         /*
 764          * TODO:
 765          * if a protocol has been registered & line discipline
 766          * un-installed for some reason - what should be done ?
 767          */
 768         spin_lock_irqsave(&st_gdata->lock, flags);
 769         for (i = ST_BT; i < ST_MAX_CHANNELS; i++) {
 770                 if (st_gdata->is_registered[i] == true)
 771                         pr_err("%d not un-registered", i);
 772                 st_gdata->list[i] = NULL;
 773                 st_gdata->is_registered[i] = false;
 774         }
 775         st_gdata->protos_registered = 0;
 776         spin_unlock_irqrestore(&st_gdata->lock, flags);
 777         /*
 778          * signal to UIM via KIM that -
 779          * N_TI_WL ldisc is un-installed
 780          */
 781         st_kim_complete(st_gdata->kim_data);
 782         st_gdata->tty = NULL;
 783         /* Flush any pending characters in the driver and discipline. */
 784         tty_ldisc_flush(tty);
 785         tty_driver_flush_buffer(tty);
 786
 787         spin_lock_irqsave(&st_gdata->lock, flags);
 788         /* empty out txq and tx_waitq */
 789         skb_queue_purge(&st_gdata->txq);
 790         skb_queue_purge(&st_gdata->tx_waitq);
 791         /* reset the TTY Rx states of ST */
 792         st_gdata->rx_count = 0;
 793         st_gdata->rx_state = ST_W4_PACKET_TYPE;
 794         kfree_skb(st_gdata->rx_skb);
 795         st_gdata->rx_skb = NULL;
 796         spin_unlock_irqrestore(&st_gdata->lock, flags);
 797
 798         pr_debug("%s: done ", __func__);
 799 }
 800
 801 static void st_tty_receive(struct tty_struct *tty, const unsigned char *data,
 802                            char *tty_flags, int count)
 803 {
 804 #ifdef VERBOSE
 805         print_hex_dump(KERN_DEBUG, ">in>", DUMP_PREFIX_NONE,
 806                 16, 1, data, count, 0);
 807 #endif
 808
 809         /*
 810          * if fw download is in progress then route incoming data
 811          * to KIM for validation
 812          */
 813         st_recv(tty->disc_data, data, count);
 814         pr_debug("done %s", __func__);
 815 }
 816
 817 /*
 818  * wake-up function called in from the TTY layer
 819  * inside the internal wakeup function will be called
 820  */
 821 static void st_tty_wakeup(struct tty_struct *tty)
 822 {
 823         struct  st_data_s *st_gdata = tty->disc_data;
 824         pr_debug("%s ", __func__);
 825         /* don't do an wakeup for now */
 826         clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
 827
 828         /*
 829          * schedule the internal wakeup instead of calling directly to
 830          * avoid lockup (port->lock needed in tty->ops->write is
 831          * already taken here
 832          */
 833         schedule_work(&st_gdata->work_write_wakeup);
 834 }
 835
 836 static void st_tty_flush_buffer(struct tty_struct *tty)
 837 {
 838         struct  st_data_s *st_gdata = tty->disc_data;
 839         pr_debug("%s ", __func__);
 840
 841         kfree_skb(st_gdata->tx_skb);
 842         st_gdata->tx_skb = NULL;
 843
 844         tty_driver_flush_buffer(tty);
 845         return;
 846 }
 847
 848 static struct tty_ldisc_ops st_ldisc_ops = {
 849         .magic = TTY_LDISC_MAGIC,
 850         .name = "n_st",
 851         .open = st_tty_open,
 852         .close = st_tty_close,
 853         .receive_buf = st_tty_receive,
 854         .write_wakeup = st_tty_wakeup,
 855         .flush_buffer = st_tty_flush_buffer,
 856         .owner = THIS_MODULE
 857 };
 858
 859 /********************************************************************/
 860 int st_core_init(struct st_data_s **core_data)
 861 {
 862         struct st_data_s *st_gdata;
 863         long err;
 864
 865         err = tty_register_ldisc(N_TI_WL, &st_ldisc_ops);
 866         if (err) {
 867                 pr_err("error registering %d line discipline %ld",
 868                            N_TI_WL, err);
 869                 return err;
 870         }
 871         pr_debug("registered n_shared line discipline");
 872
 873         st_gdata = kzalloc(sizeof(struct st_data_s), GFP_KERNEL);
 874         if (!st_gdata) {
 875                 pr_err("memory allocation failed");
 876                 err = tty_unregister_ldisc(N_TI_WL);
 877                 if (err)
 878                         pr_err("unable to un-register ldisc %ld", err);
 879                 err = -ENOMEM;
 880                 return err;
 881         }
 882
 883         /* Initialize ST TxQ and Tx waitQ queue head. All BT/FM/GPS module skb's
 884          * will be pushed in this queue for actual transmission.
 885          */
 886         skb_queue_head_init(&st_gdata->txq);
 887         skb_queue_head_init(&st_gdata->tx_waitq);
 888
 889         /* Locking used in st_int_enqueue() to avoid multiple execution */
 890         spin_lock_init(&st_gdata->lock);
 891
 892         err = st_ll_init(st_gdata);
 893         if (err) {
 894                 pr_err("error during st_ll initialization(%ld)", err);
 895                 kfree(st_gdata);
 896                 err = tty_unregister_ldisc(N_TI_WL);
 897                 if (err)
 898                         pr_err("unable to un-register ldisc");
 899                 return err;
 900         }
 901
 902         INIT_WORK(&st_gdata->work_write_wakeup, work_fn_write_wakeup);
 903
 904         *core_data = st_gdata;
 905         return 0;
 906 }
 907
 908 void st_core_exit(struct st_data_s *st_gdata)
 909 {
 910         long err;
 911         /* internal module cleanup */
 912         err = st_ll_deinit(st_gdata);
 913         if (err)
 914                 pr_err("error during deinit of ST LL %ld", err);
 915
 916         if (st_gdata != NULL) {
 917                 /* Free ST Tx Qs and skbs */
 918                 skb_queue_purge(&st_gdata->txq);
 919                 skb_queue_purge(&st_gdata->tx_waitq);
 920                 kfree_skb(st_gdata->rx_skb);
 921                 kfree_skb(st_gdata->tx_skb);
 922                 /* TTY ldisc cleanup */
 923                 err = tty_unregister_ldisc(N_TI_WL);
 924                 if (err)
 925                         pr_err("unable to un-register ldisc %ld", err);
 926                 /* free the global data pointer */
 927                 kfree(st_gdata);
 928         }
 929 }