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 /*
  22  * function pointer pointing to either,
  23  * st_kim_recv during registration to receive fw download responses
  24  * st_int_recv after registration to receive proto stack responses
  25  */
  26 static void (*st_recv) (void *, const unsigned char *, long);
  27
  28 /********************************************************************/
  29 static void add_channel_to_table(struct st_data_s *st_gdata,
  30                 struct st_proto_s *new_proto)
  31 {
  32         pr_info("%s: id %d\n", __func__, new_proto->chnl_id);
  33         /* list now has the channel id as index itself */
  34         st_gdata->list[new_proto->chnl_id] = new_proto;
  35         st_gdata->is_registered[new_proto->chnl_id] = true;
  36 }
  37
  38 static void remove_channel_from_table(struct st_data_s *st_gdata,
  39                 struct st_proto_s *proto)
  40 {
  41         pr_info("%s: id %d\n", __func__, proto->chnl_id);
  42 /*      st_gdata->list[proto->chnl_id] = NULL; */
  43         st_gdata->is_registered[proto->chnl_id] = false;
  44 }
  45
  46 /*
  47  * called from KIM during firmware download.
  48  *
  49  * This is a wrapper function to tty->ops->write_room.
  50  * It returns number of free space available in
  51  * uart tx buffer.
  52  */
  53 int st_get_uart_wr_room(struct st_data_s *st_gdata)
  54 {
  55         struct tty_struct *tty;
  56         if (unlikely(st_gdata == NULL || st_gdata->tty == NULL)) {
  57                 pr_err("tty unavailable to perform write");
  58                 return -1;
  59         }
  60         tty = st_gdata->tty;
  61         return tty->ops->write_room(tty);
  62 }
  63
  64 /*
  65  * can be called in from
  66  * -- KIM (during fw download)
  67  * -- ST Core (during st_write)
  68  *
  69  *  This is the internal write function - a wrapper
  70  *  to tty->ops->write
  71  */
  72 int st_int_write(struct st_data_s *st_gdata,
  73         const unsigned char *data, int count)
  74 {
  75         struct tty_struct *tty;
  76         if (unlikely(st_gdata == NULL || st_gdata->tty == NULL)) {
  77                 pr_err("tty unavailable to perform write");
  78                 return -EINVAL;
  79         }
  80         tty = st_gdata->tty;
  81 #ifdef VERBOSE
  82         print_hex_dump(KERN_DEBUG, "<out<", DUMP_PREFIX_NONE,
  83                 16, 1, data, count, 0);
  84 #endif
  85         return tty->ops->write(tty, data, count);
  86
  87 }
  88
  89 /*
  90  * push the skb received to relevant
  91  * protocol stacks
  92  */
  93 static void st_send_frame(unsigned char chnl_id, struct st_data_s *st_gdata)
  94 {
  95         pr_debug(" %s(prot:%d) ", __func__, chnl_id);
  96
  97         if (unlikely
  98             (st_gdata == NULL || st_gdata->rx_skb == NULL
  99              || st_gdata->is_registered[chnl_id] == false)) {
 100                 pr_err("chnl_id %d not registered, no data to send?",
 101                            chnl_id);
 102                 kfree_skb(st_gdata->rx_skb);
 103                 return;
 104         }
 105         /*
 106          * this cannot fail
 107          * this shouldn't take long
 108          * - should be just skb_queue_tail for the
 109          *   protocol stack driver
 110          */
 111         if (likely(st_gdata->list[chnl_id]->recv != NULL)) {
 112                 if (unlikely
 113                         (st_gdata->list[chnl_id]->recv
 114                         (st_gdata->list[chnl_id]->priv_data, st_gdata->rx_skb)
 115                              != 0)) {
 116                         pr_err(" proto stack %d's ->recv failed", chnl_id);
 117                         kfree_skb(st_gdata->rx_skb);
 118                         return;
 119                 }
 120         } else {
 121                 pr_err(" proto stack %d's ->recv null", chnl_id);
 122                 kfree_skb(st_gdata->rx_skb);
 123         }
 124         return;
 125 }
 126
 127 /*
 128  * st_reg_complete - to call registration complete callbacks
 129  * of all protocol stack drivers
 130  * This function is being called with spin lock held, protocol drivers are
 131  * only expected to complete their waits and do nothing more than that.
 132  */
 133 static void st_reg_complete(struct st_data_s *st_gdata, int err)
 134 {
 135         unsigned char i = 0;
 136         pr_info(" %s ", __func__);
 137         for (i = 0; i < ST_MAX_CHANNELS; i++) {
 138                 if (likely(st_gdata != NULL &&
 139                         st_gdata->is_registered[i] == true &&
 140                                 st_gdata->list[i]->reg_complete_cb != NULL)) {
 141                         st_gdata->list[i]->reg_complete_cb
 142                                 (st_gdata->list[i]->priv_data, err);
 143                         pr_info("protocol %d's cb sent %d\n", i, err);
 144                         if (err) { /* cleanup registered protocol */
 145                                 st_gdata->is_registered[i] = false;
 146                                 if (st_gdata->protos_registered)
 147                                         st_gdata->protos_registered--;
 148                         }
 149                 }
 150         }
 151 }
 152
 153 static inline int st_check_data_len(struct st_data_s *st_gdata,
 154         unsigned char chnl_id, int len)
 155 {
 156         int room = skb_tailroom(st_gdata->rx_skb);
 157
 158         pr_debug("len %d room %d", len, room);
 159
 160         if (!len) {
 161                 /*
 162                  * Received packet has only packet header and
 163                  * has zero length payload. So, ask ST CORE to
 164                  * forward the packet to protocol driver (BT/FM/GPS)
 165                  */
 166                 st_send_frame(chnl_id, st_gdata);
 167
 168         } else if (len > room) {
 169                 /*
 170                  * Received packet's payload length is larger.
 171                  * We can't accommodate it in created skb.
 172                  */
 173                 pr_err("Data length is too large len %d room %d", len,
 174                            room);
 175                 kfree_skb(st_gdata->rx_skb);
 176         } else {
 177                 /*
 178                  * Packet header has non-zero payload length and
 179                  * we have enough space in created skb. Lets read
 180                  * payload data */
 181                 st_gdata->rx_state = ST_W4_DATA;
 182                 st_gdata->rx_count = len;
 183                 return len;
 184         }
 185
 186         /* Change ST state to continue to process next packet */
 187         st_gdata->rx_state = ST_W4_PACKET_TYPE;
 188         st_gdata->rx_skb = NULL;
 189         st_gdata->rx_count = 0;
 190         st_gdata->rx_chnl = 0;
 191
 192         return 0;
 193 }
 194
 195 /*
 196  * st_wakeup_ack - internal function for action when wake-up ack
 197  *      received
 198  */
 199 static inline void st_wakeup_ack(struct st_data_s *st_gdata,
 200         unsigned char cmd)
 201 {
 202         struct sk_buff *waiting_skb;
 203         unsigned long flags = 0;
 204
 205         spin_lock_irqsave(&st_gdata->lock, flags);
 206         /*
 207          * de-Q from waitQ and Q in txQ now that the
 208          * chip is awake
 209          */
 210         while ((waiting_skb = skb_dequeue(&st_gdata->tx_waitq)))
 211                 skb_queue_tail(&st_gdata->txq, waiting_skb);
 212
 213         /* state forwarded to ST LL */
 214         st_ll_sleep_state(st_gdata, (unsigned long)cmd);
 215         spin_unlock_irqrestore(&st_gdata->lock, flags);
 216
 217         /* wake up to send the recently copied skbs from waitQ */
 218         st_tx_wakeup(st_gdata);
 219 }
 220
 221 /*
 222  * st_int_recv - ST's internal receive function.
 223  *      Decodes received RAW data and forwards to corresponding
 224  *      client drivers (Bluetooth,FM,GPS..etc).
 225  *      This can receive various types of packets,
 226  *      HCI-Events, ACL, SCO, 4 types of HCI-LL PM packets
 227  *      CH-8 packets from FM, CH-9 packets from GPS cores.
 228  */
 229 void st_int_recv(void *disc_data,
 230         const unsigned char *data, long count)
 231 {
 232         char *ptr;
 233         struct st_proto_s *proto;
 234         unsigned short payload_len = 0;
 235         int len = 0;
 236         unsigned char type = 0;
 237         unsigned char *plen;
 238         struct st_data_s *st_gdata = (struct st_data_s *)disc_data;
 239         unsigned long flags;
 240
 241         ptr = (char *)data;
 242         /* tty_receive sent null ? */
 243         if (unlikely(ptr == NULL) || (st_gdata == NULL)) {
 244                 pr_err(" received null from TTY ");
 245                 return;
 246         }
 247
 248         pr_debug("count %ld rx_state %ld"
 249                    "rx_count %ld", count, st_gdata->rx_state,
 250                    st_gdata->rx_count);
 251
 252         spin_lock_irqsave(&st_gdata->lock, flags);
 253         /* Decode received bytes here */
 254         while (count) {
 255                 if (st_gdata->rx_count) {
 256                         len = min_t(unsigned int, st_gdata->rx_count, count);
 257                         skb_put_data(st_gdata->rx_skb, ptr, len);
 258                         st_gdata->rx_count -= len;
 259                         count -= len;
 260                         ptr += len;
 261
 262                         if (st_gdata->rx_count)
 263                                 continue;
 264
 265                         /* Check ST RX state machine , where are we? */
 266                         switch (st_gdata->rx_state) {
 267                         /* Waiting for complete packet ? */
 268                         case ST_W4_DATA:
 269                                 pr_debug("Complete pkt received");
 270                                 /*
 271                                  * Ask ST CORE to forward
 272                                  * the packet to protocol driver
 273                                  */
 274                                 st_send_frame(st_gdata->rx_chnl, st_gdata);
 275
 276                                 st_gdata->rx_state = ST_W4_PACKET_TYPE;
 277                                 st_gdata->rx_skb = NULL;
 278                                 continue;
 279                         /* parse the header to know details */
 280                         case ST_W4_HEADER:
 281                                 proto = st_gdata->list[st_gdata->rx_chnl];
 282                                 plen =
 283                                 &st_gdata->rx_skb->data
 284                                 [proto->offset_len_in_hdr];
 285                                 pr_debug("plen pointing to %x\n", *plen);
 286                                 if (proto->len_size == 1) /* 1 byte len field */
 287                                         payload_len = *(unsigned char *)plen;
 288                                 else if (proto->len_size == 2)
 289                                         payload_len =
 290                                         __le16_to_cpu(*(unsigned short *)plen);
 291                                 else
 292                                         pr_info("%s: invalid length "
 293                                         "for id %d\n",
 294                                         __func__, proto->chnl_id);
 295                                 st_check_data_len(st_gdata, proto->chnl_id,
 296                                                 payload_len);
 297                                 pr_debug("off %d, pay len %d\n",
 298                                         proto->offset_len_in_hdr, payload_len);
 299                                 continue;
 300                         }       /* end of switch rx_state */
 301                 }
 302
 303                 /* end of if rx_count */
 304
 305                 /*
 306                  * Check first byte of packet and identify module
 307                  * owner (BT/FM/GPS)
 308                  */
 309                 switch (*ptr) {
 310                 case LL_SLEEP_IND:
 311                 case LL_SLEEP_ACK:
 312                 case LL_WAKE_UP_IND:
 313                         pr_debug("PM packet");
 314                         /*
 315                          * this takes appropriate action based on
 316                          * sleep state received --
 317                          */
 318                         st_ll_sleep_state(st_gdata, *ptr);
 319                         /*
 320                          * if WAKEUP_IND collides copy from waitq to txq
 321                          * and assume chip awake
 322                          */
 323                         spin_unlock_irqrestore(&st_gdata->lock, flags);
 324                         if (st_ll_getstate(st_gdata) == ST_LL_AWAKE)
 325                                 st_wakeup_ack(st_gdata, LL_WAKE_UP_ACK);
 326                         spin_lock_irqsave(&st_gdata->lock, flags);
 327
 328                         ptr++;
 329                         count--;
 330                         continue;
 331                 case LL_WAKE_UP_ACK:
 332                         pr_debug("PM packet");
 333
 334                         spin_unlock_irqrestore(&st_gdata->lock, flags);
 335                         /* wake up ack received */
 336                         st_wakeup_ack(st_gdata, *ptr);
 337                         spin_lock_irqsave(&st_gdata->lock, flags);
 338
 339                         ptr++;
 340                         count--;
 341                         continue;
 342                         /* Unknow packet? */
 343                 default:
 344                         type = *ptr;
 345
 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                 /*
 578                  * this may take a while to complete
 579                  * since it involves BT fw download
 580                  */
 581                 err = st_kim_start(st_gdata->kim_data);
 582                 if (err != 0) {
 583                         clear_bit(ST_REG_IN_PROGRESS, &st_gdata->st_state);
 584                         if ((st_gdata->protos_registered != ST_EMPTY) &&
 585                             (test_bit(ST_REG_PENDING, &st_gdata->st_state))) {
 586                                 pr_err(" KIM failure complete callback ");
 587                                 spin_lock_irqsave(&st_gdata->lock, flags);
 588                                 st_reg_complete(st_gdata, err);
 589                                 spin_unlock_irqrestore(&st_gdata->lock, flags);
 590                                 clear_bit(ST_REG_PENDING, &st_gdata->st_state);
 591                         }
 592                         return -EINVAL;
 593                 }
 594
 595                 spin_lock_irqsave(&st_gdata->lock, flags);
 596
 597                 clear_bit(ST_REG_IN_PROGRESS, &st_gdata->st_state);
 598                 st_recv = st_int_recv;
 599
 600                 /*
 601                  * this is where all pending registration
 602                  * are signalled to be complete by calling callback functions
 603                  */
 604                 if ((st_gdata->protos_registered != ST_EMPTY) &&
 605                     (test_bit(ST_REG_PENDING, &st_gdata->st_state))) {
 606                         pr_debug(" call reg complete callback ");
 607                         st_reg_complete(st_gdata, 0);
 608                 }
 609                 clear_bit(ST_REG_PENDING, &st_gdata->st_state);
 610
 611                 /*
 612                  * check for already registered once more,
 613                  * since the above check is old
 614                  */
 615                 if (st_gdata->is_registered[new_proto->chnl_id] == true) {
 616                         pr_err(" proto %d already registered ",
 617                                    new_proto->chnl_id);
 618                         spin_unlock_irqrestore(&st_gdata->lock, flags);
 619                         return -EALREADY;
 620                 }
 621
 622                 add_channel_to_table(st_gdata, new_proto);
 623                 st_gdata->protos_registered++;
 624                 new_proto->write = st_write;
 625                 spin_unlock_irqrestore(&st_gdata->lock, flags);
 626                 return err;
 627         }
 628         /* if fw is already downloaded & new stack registers protocol */
 629         else {
 630                 add_channel_to_table(st_gdata, new_proto);
 631                 st_gdata->protos_registered++;
 632                 new_proto->write = st_write;
 633
 634                 /* lock already held before entering else */
 635                 spin_unlock_irqrestore(&st_gdata->lock, flags);
 636                 return err;
 637         }
 638 }
 639 EXPORT_SYMBOL_GPL(st_register);
 640
 641 /*
 642  * to unregister a protocol -
 643  * to be called from protocol stack driver
 644  */
 645 long st_unregister(struct st_proto_s *proto)
 646 {
 647         long err = 0;
 648         unsigned long flags = 0;
 649         struct st_data_s        *st_gdata;
 650
 651         pr_debug("%s: %d ", __func__, proto->chnl_id);
 652
 653         st_kim_ref(&st_gdata, 0);
 654         if (!st_gdata || proto->chnl_id >= ST_MAX_CHANNELS) {
 655                 pr_err(" chnl_id %d not supported", proto->chnl_id);
 656                 return -EPROTONOSUPPORT;
 657         }
 658
 659         spin_lock_irqsave(&st_gdata->lock, flags);
 660
 661         if (st_gdata->is_registered[proto->chnl_id] == false) {
 662                 pr_err(" chnl_id %d not registered", proto->chnl_id);
 663                 spin_unlock_irqrestore(&st_gdata->lock, flags);
 664                 return -EPROTONOSUPPORT;
 665         }
 666
 667         if (st_gdata->protos_registered)
 668                 st_gdata->protos_registered--;
 669
 670         remove_channel_from_table(st_gdata, proto);
 671         spin_unlock_irqrestore(&st_gdata->lock, flags);
 672
 673         if ((st_gdata->protos_registered == ST_EMPTY) &&
 674             (!test_bit(ST_REG_PENDING, &st_gdata->st_state))) {
 675                 pr_info(" all chnl_ids unregistered ");
 676
 677                 /* stop traffic on tty */
 678                 if (st_gdata->tty) {
 679                         tty_ldisc_flush(st_gdata->tty);
 680                         stop_tty(st_gdata->tty);
 681                 }
 682
 683                 /* all chnl_ids now unregistered */
 684                 st_kim_stop(st_gdata->kim_data);
 685                 /* disable ST LL */
 686                 st_ll_disable(st_gdata);
 687         }
 688         return err;
 689 }
 690
 691 /*
 692  * called in protocol stack drivers
 693  * via the write function pointer
 694  */
 695 long st_write(struct sk_buff *skb)
 696 {
 697         struct st_data_s *st_gdata;
 698         long len;
 699
 700         st_kim_ref(&st_gdata, 0);
 701         if (unlikely(skb == NULL || st_gdata == NULL
 702                 || st_gdata->tty == NULL)) {
 703                 pr_err("data/tty unavailable to perform write");
 704                 return -EINVAL;
 705         }
 706
 707         pr_debug("%d to be written", skb->len);
 708         len = skb->len;
 709
 710         /* st_ll to decide where to enqueue the skb */
 711         st_int_enqueue(st_gdata, skb);
 712         /* wake up */
 713         st_tx_wakeup(st_gdata);
 714
 715         /* return number of bytes written */
 716         return len;
 717 }
 718
 719 /* for protocols making use of shared transport */
 720 EXPORT_SYMBOL_GPL(st_unregister);
 721
 722 /********************************************************************/
 723 /*
 724  * functions called from TTY layer
 725  */
 726 static int st_tty_open(struct tty_struct *tty)
 727 {
 728         struct st_data_s *st_gdata;
 729         pr_info("%s ", __func__);
 730
 731         st_kim_ref(&st_gdata, 0);
 732         st_gdata->tty = tty;
 733         tty->disc_data = st_gdata;
 734
 735         /* don't do an wakeup for now */
 736         clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
 737
 738         /* mem already allocated
 739          */
 740         tty->receive_room = 65536;
 741         /* Flush any pending characters in the driver and discipline. */
 742         tty_ldisc_flush(tty);
 743         tty_driver_flush_buffer(tty);
 744         /*
 745          * signal to UIM via KIM that -
 746          * installation of N_TI_WL ldisc is complete
 747          */
 748         st_kim_complete(st_gdata->kim_data);
 749         pr_debug("done %s", __func__);
 750
 751         return 0;
 752 }
 753
 754 static void st_tty_close(struct tty_struct *tty)
 755 {
 756         unsigned char i;
 757         unsigned long flags;
 758         struct  st_data_s *st_gdata = tty->disc_data;
 759
 760         pr_info("%s ", __func__);
 761
 762         /*
 763          * TODO:
 764          * if a protocol has been registered & line discipline
 765          * un-installed for some reason - what should be done ?
 766          */
 767         spin_lock_irqsave(&st_gdata->lock, flags);
 768         for (i = ST_BT; i < ST_MAX_CHANNELS; i++) {
 769                 if (st_gdata->is_registered[i] == true)
 770                         pr_err("%d not un-registered", i);
 771                 st_gdata->list[i] = NULL;
 772                 st_gdata->is_registered[i] = false;
 773         }
 774         st_gdata->protos_registered = 0;
 775         spin_unlock_irqrestore(&st_gdata->lock, flags);
 776         /*
 777          * signal to UIM via KIM that -
 778          * N_TI_WL ldisc is un-installed
 779          */
 780         st_kim_complete(st_gdata->kim_data);
 781         st_gdata->tty = NULL;
 782         /* Flush any pending characters in the driver and discipline. */
 783         tty_ldisc_flush(tty);
 784         tty_driver_flush_buffer(tty);
 785
 786         spin_lock_irqsave(&st_gdata->lock, flags);
 787         /* empty out txq and tx_waitq */
 788         skb_queue_purge(&st_gdata->txq);
 789         skb_queue_purge(&st_gdata->tx_waitq);
 790         /* reset the TTY Rx states of ST */
 791         st_gdata->rx_count = 0;
 792         st_gdata->rx_state = ST_W4_PACKET_TYPE;
 793         kfree_skb(st_gdata->rx_skb);
 794         st_gdata->rx_skb = NULL;
 795         spin_unlock_irqrestore(&st_gdata->lock, flags);
 796
 797         pr_debug("%s: done ", __func__);
 798 }
 799
 800 static void st_tty_receive(struct tty_struct *tty, const unsigned char *data,
 801                            char *tty_flags, int count)
 802 {
 803 #ifdef VERBOSE
 804         print_hex_dump(KERN_DEBUG, ">in>", DUMP_PREFIX_NONE,
 805                 16, 1, data, count, 0);
 806 #endif
 807
 808         /*
 809          * if fw download is in progress then route incoming data
 810          * to KIM for validation
 811          */
 812         st_recv(tty->disc_data, data, count);
 813         pr_debug("done %s", __func__);
 814 }
 815
 816 /*
 817  * wake-up function called in from the TTY layer
 818  * inside the internal wakeup function will be called
 819  */
 820 static void st_tty_wakeup(struct tty_struct *tty)
 821 {
 822         struct  st_data_s *st_gdata = tty->disc_data;
 823         pr_debug("%s ", __func__);
 824         /* don't do an wakeup for now */
 825         clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
 826
 827         /*
 828          * schedule the internal wakeup instead of calling directly to
 829          * avoid lockup (port->lock needed in tty->ops->write is
 830          * already taken here
 831          */
 832         schedule_work(&st_gdata->work_write_wakeup);
 833 }
 834
 835 static void st_tty_flush_buffer(struct tty_struct *tty)
 836 {
 837         struct  st_data_s *st_gdata = tty->disc_data;
 838         pr_debug("%s ", __func__);
 839
 840         kfree_skb(st_gdata->tx_skb);
 841         st_gdata->tx_skb = NULL;
 842
 843         tty_driver_flush_buffer(tty);
 844         return;
 845 }
 846
 847 static struct tty_ldisc_ops st_ldisc_ops = {
 848         .name = "n_st",
 849         .open = st_tty_open,
 850         .close = st_tty_close,
 851         .receive_buf = st_tty_receive,
 852         .write_wakeup = st_tty_wakeup,
 853         .flush_buffer = st_tty_flush_buffer,
 854         .owner = THIS_MODULE
 855 };
 856
 857 /********************************************************************/
 858 int st_core_init(struct st_data_s **core_data)
 859 {
 860         struct st_data_s *st_gdata;
 861         long err;
 862
 863         err = tty_register_ldisc(N_TI_WL, &st_ldisc_ops);
 864         if (err) {
 865                 pr_err("error registering %d line discipline %ld",
 866                            N_TI_WL, err);
 867                 return err;
 868         }
 869         pr_debug("registered n_shared line discipline");
 870
 871         st_gdata = kzalloc(sizeof(struct st_data_s), GFP_KERNEL);
 872         if (!st_gdata) {
 873                 pr_err("memory allocation failed");
 874                 err = tty_unregister_ldisc(N_TI_WL);
 875                 if (err)
 876                         pr_err("unable to un-register ldisc %ld", err);
 877                 err = -ENOMEM;
 878                 return err;
 879         }
 880
 881         /* Initialize ST TxQ and Tx waitQ queue head. All BT/FM/GPS module skb's
 882          * will be pushed in this queue for actual transmission.
 883          */
 884         skb_queue_head_init(&st_gdata->txq);
 885         skb_queue_head_init(&st_gdata->tx_waitq);
 886
 887         /* Locking used in st_int_enqueue() to avoid multiple execution */
 888         spin_lock_init(&st_gdata->lock);
 889
 890         err = st_ll_init(st_gdata);
 891         if (err) {
 892                 pr_err("error during st_ll initialization(%ld)", err);
 893                 kfree(st_gdata);
 894                 err = tty_unregister_ldisc(N_TI_WL);
 895                 if (err)
 896                         pr_err("unable to un-register ldisc");
 897                 return err;
 898         }
 899
 900         INIT_WORK(&st_gdata->work_write_wakeup, work_fn_write_wakeup);
 901
 902         *core_data = st_gdata;
 903         return 0;
 904 }
 905
 906 void st_core_exit(struct st_data_s *st_gdata)
 907 {
 908         long err;
 909         /* internal module cleanup */
 910         err = st_ll_deinit(st_gdata);
 911         if (err)
 912                 pr_err("error during deinit of ST LL %ld", err);
 913
 914         if (st_gdata != NULL) {
 915                 /* Free ST Tx Qs and skbs */
 916                 skb_queue_purge(&st_gdata->txq);
 917                 skb_queue_purge(&st_gdata->tx_waitq);
 918                 kfree_skb(st_gdata->rx_skb);
 919                 kfree_skb(st_gdata->tx_skb);
 920                 /* TTY ldisc cleanup */
 921                 err = tty_unregister_ldisc(N_TI_WL);
 922                 if (err)
 923                         pr_err("unable to un-register ldisc %ld", err);
 924                 /* free the global data pointer */
 925                 kfree(st_gdata);
 926         }
 927 }