linux/drivers/misc/ti-st/st_core.c
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   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
  19extern void st_kim_recv(void *, const unsigned char *, long);
  20void 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 */
  26static void (*st_recv) (void *, const unsigned char *, long);
  27
  28/********************************************************************/
  29static 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
  38static 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 */
  53int 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 */
  72int 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 */
  93static 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 */
 133static 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
 153static 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 */
 199static 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 */
 229void 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        }
 387done:
 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 */
 399static 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 */
 421static 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 */
 463static 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}
 470void 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*/
 515void 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 */
 529long 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}
 639EXPORT_SYMBOL_GPL(st_register);
 640
 641/*
 642 * to unregister a protocol -
 643 * to be called from protocol stack driver
 644 */
 645long 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 */
 695long 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 */
 720EXPORT_SYMBOL_GPL(st_unregister);
 721
 722/********************************************************************/
 723/*
 724 * functions called from TTY layer
 725 */
 726static 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
 754static 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
 800static 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 */
 820static 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
 835static 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
 847static 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/********************************************************************/
 858int 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
 906void 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}
 928