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