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