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        if (unlikely(st_gdata == NULL || st_gdata->tty == NULL)) {
  56                pr_err("tty unavailable to perform write");
  57                return -1;
  58        }
  59
  60        return tty_write_room(st_gdata->tty);
  61}
  62
  63/*
  64 * can be called in from
  65 * -- KIM (during fw download)
  66 * -- ST Core (during st_write)
  67 *
  68 *  This is the internal write function - a wrapper
  69 *  to tty->ops->write
  70 */
  71int st_int_write(struct st_data_s *st_gdata,
  72        const unsigned char *data, int count)
  73{
  74        struct tty_struct *tty;
  75        if (unlikely(st_gdata == NULL || st_gdata->tty == NULL)) {
  76                pr_err("tty unavailable to perform write");
  77                return -EINVAL;
  78        }
  79        tty = st_gdata->tty;
  80#ifdef VERBOSE
  81        print_hex_dump(KERN_DEBUG, "<out<", DUMP_PREFIX_NONE,
  82                16, 1, data, count, 0);
  83#endif
  84        return tty->ops->write(tty, data, count);
  85
  86}
  87
  88/*
  89 * push the skb received to relevant
  90 * protocol stacks
  91 */
  92static void st_send_frame(unsigned char chnl_id, struct st_data_s *st_gdata)
  93{
  94        pr_debug(" %s(prot:%d) ", __func__, chnl_id);
  95
  96        if (unlikely
  97            (st_gdata == NULL || st_gdata->rx_skb == NULL
  98             || st_gdata->is_registered[chnl_id] == false)) {
  99                pr_err("chnl_id %d not registered, no data to send?",
 100                           chnl_id);
 101                kfree_skb(st_gdata->rx_skb);
 102                return;
 103        }
 104        /*
 105         * this cannot fail
 106         * this shouldn't take long
 107         * - should be just skb_queue_tail for the
 108         *   protocol stack driver
 109         */
 110        if (likely(st_gdata->list[chnl_id]->recv != NULL)) {
 111                if (unlikely
 112                        (st_gdata->list[chnl_id]->recv
 113                        (st_gdata->list[chnl_id]->priv_data, st_gdata->rx_skb)
 114                             != 0)) {
 115                        pr_err(" proto stack %d's ->recv failed", chnl_id);
 116                        kfree_skb(st_gdata->rx_skb);
 117                        return;
 118                }
 119        } else {
 120                pr_err(" proto stack %d's ->recv null", chnl_id);
 121                kfree_skb(st_gdata->rx_skb);
 122        }
 123        return;
 124}
 125
 126/*
 127 * st_reg_complete - to call registration complete callbacks
 128 * of all protocol stack drivers
 129 * This function is being called with spin lock held, protocol drivers are
 130 * only expected to complete their waits and do nothing more than that.
 131 */
 132static void st_reg_complete(struct st_data_s *st_gdata, int err)
 133{
 134        unsigned char i = 0;
 135        pr_info(" %s ", __func__);
 136        for (i = 0; i < ST_MAX_CHANNELS; i++) {
 137                if (likely(st_gdata != NULL &&
 138                        st_gdata->is_registered[i] == true &&
 139                                st_gdata->list[i]->reg_complete_cb != NULL)) {
 140                        st_gdata->list[i]->reg_complete_cb
 141                                (st_gdata->list[i]->priv_data, err);
 142                        pr_info("protocol %d's cb sent %d\n", i, err);
 143                        if (err) { /* cleanup registered protocol */
 144                                st_gdata->is_registered[i] = false;
 145                                if (st_gdata->protos_registered)
 146                                        st_gdata->protos_registered--;
 147                        }
 148                }
 149        }
 150}
 151
 152static inline int st_check_data_len(struct st_data_s *st_gdata,
 153        unsigned char chnl_id, int len)
 154{
 155        int room = skb_tailroom(st_gdata->rx_skb);
 156
 157        pr_debug("len %d room %d", len, room);
 158
 159        if (!len) {
 160                /*
 161                 * Received packet has only packet header and
 162                 * has zero length payload. So, ask ST CORE to
 163                 * forward the packet to protocol driver (BT/FM/GPS)
 164                 */
 165                st_send_frame(chnl_id, st_gdata);
 166
 167        } else if (len > room) {
 168                /*
 169                 * Received packet's payload length is larger.
 170                 * We can't accommodate it in created skb.
 171                 */
 172                pr_err("Data length is too large len %d room %d", len,
 173                           room);
 174                kfree_skb(st_gdata->rx_skb);
 175        } else {
 176                /*
 177                 * Packet header has non-zero payload length and
 178                 * we have enough space in created skb. Lets read
 179                 * payload data */
 180                st_gdata->rx_state = ST_W4_DATA;
 181                st_gdata->rx_count = len;
 182                return len;
 183        }
 184
 185        /* Change ST state to continue to process next packet */
 186        st_gdata->rx_state = ST_W4_PACKET_TYPE;
 187        st_gdata->rx_skb = NULL;
 188        st_gdata->rx_count = 0;
 189        st_gdata->rx_chnl = 0;
 190
 191        return 0;
 192}
 193
 194/*
 195 * st_wakeup_ack - internal function for action when wake-up ack
 196 *      received
 197 */
 198static inline void st_wakeup_ack(struct st_data_s *st_gdata,
 199        unsigned char cmd)
 200{
 201        struct sk_buff *waiting_skb;
 202        unsigned long flags = 0;
 203
 204        spin_lock_irqsave(&st_gdata->lock, flags);
 205        /*
 206         * de-Q from waitQ and Q in txQ now that the
 207         * chip is awake
 208         */
 209        while ((waiting_skb = skb_dequeue(&st_gdata->tx_waitq)))
 210                skb_queue_tail(&st_gdata->txq, waiting_skb);
 211
 212        /* state forwarded to ST LL */
 213        st_ll_sleep_state(st_gdata, (unsigned long)cmd);
 214        spin_unlock_irqrestore(&st_gdata->lock, flags);
 215
 216        /* wake up to send the recently copied skbs from waitQ */
 217        st_tx_wakeup(st_gdata);
 218}
 219
 220/*
 221 * st_int_recv - ST's internal receive function.
 222 *      Decodes received RAW data and forwards to corresponding
 223 *      client drivers (Bluetooth,FM,GPS..etc).
 224 *      This can receive various types of packets,
 225 *      HCI-Events, ACL, SCO, 4 types of HCI-LL PM packets
 226 *      CH-8 packets from FM, CH-9 packets from GPS cores.
 227 */
 228void st_int_recv(void *disc_data,
 229        const unsigned char *data, long count)
 230{
 231        char *ptr;
 232        struct st_proto_s *proto;
 233        unsigned short payload_len = 0;
 234        int len = 0;
 235        unsigned char type = 0;
 236        unsigned char *plen;
 237        struct st_data_s *st_gdata = (struct st_data_s *)disc_data;
 238        unsigned long flags;
 239
 240        ptr = (char *)data;
 241        /* tty_receive sent null ? */
 242        if (unlikely(ptr == NULL) || (st_gdata == NULL)) {
 243                pr_err(" received null from TTY ");
 244                return;
 245        }
 246
 247        pr_debug("count %ld rx_state %ld"
 248                   "rx_count %ld", count, st_gdata->rx_state,
 249                   st_gdata->rx_count);
 250
 251        spin_lock_irqsave(&st_gdata->lock, flags);
 252        /* Decode received bytes here */
 253        while (count) {
 254                if (st_gdata->rx_count) {
 255                        len = min_t(unsigned int, st_gdata->rx_count, count);
 256                        skb_put_data(st_gdata->rx_skb, ptr, len);
 257                        st_gdata->rx_count -= len;
 258                        count -= len;
 259                        ptr += len;
 260
 261                        if (st_gdata->rx_count)
 262                                continue;
 263
 264                        /* Check ST RX state machine , where are we? */
 265                        switch (st_gdata->rx_state) {
 266                        /* Waiting for complete packet ? */
 267                        case ST_W4_DATA:
 268                                pr_debug("Complete pkt received");
 269                                /*
 270                                 * Ask ST CORE to forward
 271                                 * the packet to protocol driver
 272                                 */
 273                                st_send_frame(st_gdata->rx_chnl, st_gdata);
 274
 275                                st_gdata->rx_state = ST_W4_PACKET_TYPE;
 276                                st_gdata->rx_skb = NULL;
 277                                continue;
 278                        /* parse the header to know details */
 279                        case ST_W4_HEADER:
 280                                proto = st_gdata->list[st_gdata->rx_chnl];
 281                                plen =
 282                                &st_gdata->rx_skb->data
 283                                [proto->offset_len_in_hdr];
 284                                pr_debug("plen pointing to %x\n", *plen);
 285                                if (proto->len_size == 1) /* 1 byte len field */
 286                                        payload_len = *(unsigned char *)plen;
 287                                else if (proto->len_size == 2)
 288                                        payload_len =
 289                                        __le16_to_cpu(*(unsigned short *)plen);
 290                                else
 291                                        pr_info("%s: invalid length "
 292                                        "for id %d\n",
 293                                        __func__, proto->chnl_id);
 294                                st_check_data_len(st_gdata, proto->chnl_id,
 295                                                payload_len);
 296                                pr_debug("off %d, pay len %d\n",
 297                                        proto->offset_len_in_hdr, payload_len);
 298                                continue;
 299                        }       /* end of switch rx_state */
 300                }
 301
 302                /* end of if rx_count */
 303
 304                /*
 305                 * Check first byte of packet and identify module
 306                 * owner (BT/FM/GPS)
 307                 */
 308                switch (*ptr) {
 309                case LL_SLEEP_IND:
 310                case LL_SLEEP_ACK:
 311                case LL_WAKE_UP_IND:
 312                        pr_debug("PM packet");
 313                        /*
 314                         * this takes appropriate action based on
 315                         * sleep state received --
 316                         */
 317                        st_ll_sleep_state(st_gdata, *ptr);
 318                        /*
 319                         * if WAKEUP_IND collides copy from waitq to txq
 320                         * and assume chip awake
 321                         */
 322                        spin_unlock_irqrestore(&st_gdata->lock, flags);
 323                        if (st_ll_getstate(st_gdata) == ST_LL_AWAKE)
 324                                st_wakeup_ack(st_gdata, LL_WAKE_UP_ACK);
 325                        spin_lock_irqsave(&st_gdata->lock, flags);
 326
 327                        ptr++;
 328                        count--;
 329                        continue;
 330                case LL_WAKE_UP_ACK:
 331                        pr_debug("PM packet");
 332
 333                        spin_unlock_irqrestore(&st_gdata->lock, flags);
 334                        /* wake up ack received */
 335                        st_wakeup_ack(st_gdata, *ptr);
 336                        spin_lock_irqsave(&st_gdata->lock, flags);
 337
 338                        ptr++;
 339                        count--;
 340                        continue;
 341                        /* Unknow packet? */
 342                default:
 343                        type = *ptr;
 344
 345                        /*
 346                         * Default case means non-HCILL packets,
 347                         * possibilities are packets for:
 348                         * (a) valid protocol -  Supported Protocols within
 349                         *     the ST_MAX_CHANNELS.
 350                         * (b) registered protocol - Checked by
 351                         *     "st_gdata->list[type] == NULL)" are supported
 352                         *     protocols only.
 353                         *  Rules out any invalid protocol and
 354                         *  unregistered protocols with channel ID < 16.
 355                         */
 356
 357                        if ((type >= ST_MAX_CHANNELS) ||
 358                                        (st_gdata->list[type] == NULL)) {
 359                                pr_err("chip/interface misbehavior: "
 360                                                "dropping frame starting "
 361                                                "with 0x%02x\n", type);
 362                                goto done;
 363                        }
 364
 365                        st_gdata->rx_skb = alloc_skb(
 366                                        st_gdata->list[type]->max_frame_size,
 367                                        GFP_ATOMIC);
 368                        if (st_gdata->rx_skb == NULL) {
 369                                pr_err("out of memory: dropping\n");
 370                                goto done;
 371                        }
 372
 373                        skb_reserve(st_gdata->rx_skb,
 374                                        st_gdata->list[type]->reserve);
 375                        /* next 2 required for BT only */
 376                        st_gdata->rx_skb->cb[0] = type; /*pkt_type*/
 377                        st_gdata->rx_skb->cb[1] = 0; /*incoming*/
 378                        st_gdata->rx_chnl = *ptr;
 379                        st_gdata->rx_state = ST_W4_HEADER;
 380                        st_gdata->rx_count = st_gdata->list[type]->hdr_len;
 381                        pr_debug("rx_count %ld\n", st_gdata->rx_count);
 382                }
 383                ptr++;
 384                count--;
 385        }
 386done:
 387        spin_unlock_irqrestore(&st_gdata->lock, flags);
 388        pr_debug("done %s", __func__);
 389        return;
 390}
 391
 392/*
 393 * st_int_dequeue - internal de-Q function.
 394 *      If the previous data set was not written
 395 *      completely, return that skb which has the pending data.
 396 *      In normal cases, return top of txq.
 397 */
 398static struct sk_buff *st_int_dequeue(struct st_data_s *st_gdata)
 399{
 400        struct sk_buff *returning_skb;
 401
 402        pr_debug("%s", __func__);
 403        if (st_gdata->tx_skb != NULL) {
 404                returning_skb = st_gdata->tx_skb;
 405                st_gdata->tx_skb = NULL;
 406                return returning_skb;
 407        }
 408        return skb_dequeue(&st_gdata->txq);
 409}
 410
 411/*
 412 * st_int_enqueue - internal Q-ing function.
 413 *      Will either Q the skb to txq or the tx_waitq
 414 *      depending on the ST LL state.
 415 *      If the chip is asleep, then Q it onto waitq and
 416 *      wakeup the chip.
 417 *      txq and waitq needs protection since the other contexts
 418 *      may be sending data, waking up chip.
 419 */
 420static void st_int_enqueue(struct st_data_s *st_gdata, struct sk_buff *skb)
 421{
 422        unsigned long flags = 0;
 423
 424        pr_debug("%s", __func__);
 425        spin_lock_irqsave(&st_gdata->lock, flags);
 426
 427        switch (st_ll_getstate(st_gdata)) {
 428        case ST_LL_AWAKE:
 429                pr_debug("ST LL is AWAKE, sending normally");
 430                skb_queue_tail(&st_gdata->txq, skb);
 431                break;
 432        case ST_LL_ASLEEP_TO_AWAKE:
 433                skb_queue_tail(&st_gdata->tx_waitq, skb);
 434                break;
 435        case ST_LL_AWAKE_TO_ASLEEP:
 436                pr_err("ST LL is illegal state(%ld),"
 437                           "purging received skb.", st_ll_getstate(st_gdata));
 438                kfree_skb(skb);
 439                break;
 440        case ST_LL_ASLEEP:
 441                skb_queue_tail(&st_gdata->tx_waitq, skb);
 442                st_ll_wakeup(st_gdata);
 443                break;
 444        default:
 445                pr_err("ST LL is illegal state(%ld),"
 446                           "purging received skb.", st_ll_getstate(st_gdata));
 447                kfree_skb(skb);
 448                break;
 449        }
 450
 451        spin_unlock_irqrestore(&st_gdata->lock, flags);
 452        pr_debug("done %s", __func__);
 453        return;
 454}
 455
 456/*
 457 * internal wakeup function
 458 * called from either
 459 * - TTY layer when write's finished
 460 * - st_write (in context of the protocol stack)
 461 */
 462static void work_fn_write_wakeup(struct work_struct *work)
 463{
 464        struct st_data_s *st_gdata = container_of(work, struct st_data_s,
 465                        work_write_wakeup);
 466
 467        st_tx_wakeup((void *)st_gdata);
 468}
 469void st_tx_wakeup(struct st_data_s *st_data)
 470{
 471        struct sk_buff *skb;
 472        unsigned long flags;    /* for irq save flags */
 473        pr_debug("%s", __func__);
 474        /* check for sending & set flag sending here */
 475        if (test_and_set_bit(ST_TX_SENDING, &st_data->tx_state)) {
 476                pr_debug("ST already sending");
 477                /* keep sending */
 478                set_bit(ST_TX_WAKEUP, &st_data->tx_state);
 479                return;
 480                /* TX_WAKEUP will be checked in another
 481                 * context
 482                 */
 483        }
 484        do {                    /* come back if st_tx_wakeup is set */
 485                /* woke-up to write */
 486                clear_bit(ST_TX_WAKEUP, &st_data->tx_state);
 487                while ((skb = st_int_dequeue(st_data))) {
 488                        int len;
 489                        spin_lock_irqsave(&st_data->lock, flags);
 490                        /* enable wake-up from TTY */
 491                        set_bit(TTY_DO_WRITE_WAKEUP, &st_data->tty->flags);
 492                        len = st_int_write(st_data, skb->data, skb->len);
 493                        skb_pull(skb, len);
 494                        /* if skb->len = len as expected, skb->len=0 */
 495                        if (skb->len) {
 496                                /* would be the next skb to be sent */
 497                                st_data->tx_skb = skb;
 498                                spin_unlock_irqrestore(&st_data->lock, flags);
 499                                break;
 500                        }
 501                        kfree_skb(skb);
 502                        spin_unlock_irqrestore(&st_data->lock, flags);
 503                }
 504                /* if wake-up is set in another context- restart sending */
 505        } while (test_bit(ST_TX_WAKEUP, &st_data->tx_state));
 506
 507        /* clear flag sending */
 508        clear_bit(ST_TX_SENDING, &st_data->tx_state);
 509}
 510
 511/********************************************************************/
 512/* functions called from ST KIM
 513*/
 514void kim_st_list_protocols(struct st_data_s *st_gdata, void *buf)
 515{
 516        seq_printf(buf, "[%d]\nBT=%c\nFM=%c\nGPS=%c\n",
 517                        st_gdata->protos_registered,
 518                        st_gdata->is_registered[0x04] == true ? 'R' : 'U',
 519                        st_gdata->is_registered[0x08] == true ? 'R' : 'U',
 520                        st_gdata->is_registered[0x09] == true ? 'R' : 'U');
 521}
 522
 523/********************************************************************/
 524/*
 525 * functions called from protocol stack drivers
 526 * to be EXPORT-ed
 527 */
 528long st_register(struct st_proto_s *new_proto)
 529{
 530        struct st_data_s        *st_gdata;
 531        long err = 0;
 532        unsigned long flags = 0;
 533
 534        st_kim_ref(&st_gdata, 0);
 535        if (st_gdata == NULL || new_proto == NULL || new_proto->recv == NULL
 536            || new_proto->reg_complete_cb == NULL) {
 537                pr_err("gdata/new_proto/recv or reg_complete_cb not ready");
 538                return -EINVAL;
 539        }
 540
 541        if (new_proto->chnl_id >= ST_MAX_CHANNELS) {
 542                pr_err("chnl_id %d not supported", new_proto->chnl_id);
 543                return -EPROTONOSUPPORT;
 544        }
 545
 546        if (st_gdata->is_registered[new_proto->chnl_id] == true) {
 547                pr_err("chnl_id %d already registered", new_proto->chnl_id);
 548                return -EALREADY;
 549        }
 550
 551        /* can be from process context only */
 552        spin_lock_irqsave(&st_gdata->lock, flags);
 553
 554        if (test_bit(ST_REG_IN_PROGRESS, &st_gdata->st_state)) {
 555                pr_info(" ST_REG_IN_PROGRESS:%d ", new_proto->chnl_id);
 556                /* fw download in progress */
 557
 558                add_channel_to_table(st_gdata, new_proto);
 559                st_gdata->protos_registered++;
 560                new_proto->write = st_write;
 561
 562                set_bit(ST_REG_PENDING, &st_gdata->st_state);
 563                spin_unlock_irqrestore(&st_gdata->lock, flags);
 564                return -EINPROGRESS;
 565        } else if (st_gdata->protos_registered == ST_EMPTY) {
 566                pr_info(" chnl_id list empty :%d ", new_proto->chnl_id);
 567                set_bit(ST_REG_IN_PROGRESS, &st_gdata->st_state);
 568                st_recv = st_kim_recv;
 569
 570                /* enable the ST LL - to set default chip state */
 571                st_ll_enable(st_gdata);
 572
 573                /* release lock previously held - re-locked below */
 574                spin_unlock_irqrestore(&st_gdata->lock, flags);
 575
 576                /*
 577                 * this may take a while to complete
 578                 * since it involves BT fw download
 579                 */
 580                err = st_kim_start(st_gdata->kim_data);
 581                if (err != 0) {
 582                        clear_bit(ST_REG_IN_PROGRESS, &st_gdata->st_state);
 583                        if ((st_gdata->protos_registered != ST_EMPTY) &&
 584                            (test_bit(ST_REG_PENDING, &st_gdata->st_state))) {
 585                                pr_err(" KIM failure complete callback ");
 586                                spin_lock_irqsave(&st_gdata->lock, flags);
 587                                st_reg_complete(st_gdata, err);
 588                                spin_unlock_irqrestore(&st_gdata->lock, flags);
 589                                clear_bit(ST_REG_PENDING, &st_gdata->st_state);
 590                        }
 591                        return -EINVAL;
 592                }
 593
 594                spin_lock_irqsave(&st_gdata->lock, flags);
 595
 596                clear_bit(ST_REG_IN_PROGRESS, &st_gdata->st_state);
 597                st_recv = st_int_recv;
 598
 599                /*
 600                 * this is where all pending registration
 601                 * are signalled to be complete by calling callback functions
 602                 */
 603                if ((st_gdata->protos_registered != ST_EMPTY) &&
 604                    (test_bit(ST_REG_PENDING, &st_gdata->st_state))) {
 605                        pr_debug(" call reg complete callback ");
 606                        st_reg_complete(st_gdata, 0);
 607                }
 608                clear_bit(ST_REG_PENDING, &st_gdata->st_state);
 609
 610                /*
 611                 * check for already registered once more,
 612                 * since the above check is old
 613                 */
 614                if (st_gdata->is_registered[new_proto->chnl_id] == true) {
 615                        pr_err(" proto %d already registered ",
 616                                   new_proto->chnl_id);
 617                        spin_unlock_irqrestore(&st_gdata->lock, flags);
 618                        return -EALREADY;
 619                }
 620
 621                add_channel_to_table(st_gdata, new_proto);
 622                st_gdata->protos_registered++;
 623                new_proto->write = st_write;
 624                spin_unlock_irqrestore(&st_gdata->lock, flags);
 625                return err;
 626        }
 627        /* if fw is already downloaded & new stack registers protocol */
 628        else {
 629                add_channel_to_table(st_gdata, new_proto);
 630                st_gdata->protos_registered++;
 631                new_proto->write = st_write;
 632
 633                /* lock already held before entering else */
 634                spin_unlock_irqrestore(&st_gdata->lock, flags);
 635                return err;
 636        }
 637}
 638EXPORT_SYMBOL_GPL(st_register);
 639
 640/*
 641 * to unregister a protocol -
 642 * to be called from protocol stack driver
 643 */
 644long st_unregister(struct st_proto_s *proto)
 645{
 646        long err = 0;
 647        unsigned long flags = 0;
 648        struct st_data_s        *st_gdata;
 649
 650        pr_debug("%s: %d ", __func__, proto->chnl_id);
 651
 652        st_kim_ref(&st_gdata, 0);
 653        if (!st_gdata || proto->chnl_id >= ST_MAX_CHANNELS) {
 654                pr_err(" chnl_id %d not supported", proto->chnl_id);
 655                return -EPROTONOSUPPORT;
 656        }
 657
 658        spin_lock_irqsave(&st_gdata->lock, flags);
 659
 660        if (st_gdata->is_registered[proto->chnl_id] == false) {
 661                pr_err(" chnl_id %d not registered", proto->chnl_id);
 662                spin_unlock_irqrestore(&st_gdata->lock, flags);
 663                return -EPROTONOSUPPORT;
 664        }
 665
 666        if (st_gdata->protos_registered)
 667                st_gdata->protos_registered--;
 668
 669        remove_channel_from_table(st_gdata, proto);
 670        spin_unlock_irqrestore(&st_gdata->lock, flags);
 671
 672        if ((st_gdata->protos_registered == ST_EMPTY) &&
 673            (!test_bit(ST_REG_PENDING, &st_gdata->st_state))) {
 674                pr_info(" all chnl_ids unregistered ");
 675
 676                /* stop traffic on tty */
 677                if (st_gdata->tty) {
 678                        tty_ldisc_flush(st_gdata->tty);
 679                        stop_tty(st_gdata->tty);
 680                }
 681
 682                /* all chnl_ids now unregistered */
 683                st_kim_stop(st_gdata->kim_data);
 684                /* disable ST LL */
 685                st_ll_disable(st_gdata);
 686        }
 687        return err;
 688}
 689
 690/*
 691 * called in protocol stack drivers
 692 * via the write function pointer
 693 */
 694long st_write(struct sk_buff *skb)
 695{
 696        struct st_data_s *st_gdata;
 697        long len;
 698
 699        st_kim_ref(&st_gdata, 0);
 700        if (unlikely(skb == NULL || st_gdata == NULL
 701                || st_gdata->tty == NULL)) {
 702                pr_err("data/tty unavailable to perform write");
 703                return -EINVAL;
 704        }
 705
 706        pr_debug("%d to be written", skb->len);
 707        len = skb->len;
 708
 709        /* st_ll to decide where to enqueue the skb */
 710        st_int_enqueue(st_gdata, skb);
 711        /* wake up */
 712        st_tx_wakeup(st_gdata);
 713
 714        /* return number of bytes written */
 715        return len;
 716}
 717
 718/* for protocols making use of shared transport */
 719EXPORT_SYMBOL_GPL(st_unregister);
 720
 721/********************************************************************/
 722/*
 723 * functions called from TTY layer
 724 */
 725static int st_tty_open(struct tty_struct *tty)
 726{
 727        struct st_data_s *st_gdata;
 728        pr_info("%s ", __func__);
 729
 730        st_kim_ref(&st_gdata, 0);
 731        st_gdata->tty = tty;
 732        tty->disc_data = st_gdata;
 733
 734        /* don't do an wakeup for now */
 735        clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
 736
 737        /* mem already allocated
 738         */
 739        tty->receive_room = 65536;
 740        /* Flush any pending characters in the driver and discipline. */
 741        tty_ldisc_flush(tty);
 742        tty_driver_flush_buffer(tty);
 743        /*
 744         * signal to UIM via KIM that -
 745         * installation of N_TI_WL ldisc is complete
 746         */
 747        st_kim_complete(st_gdata->kim_data);
 748        pr_debug("done %s", __func__);
 749
 750        return 0;
 751}
 752
 753static void st_tty_close(struct tty_struct *tty)
 754{
 755        unsigned char i;
 756        unsigned long flags;
 757        struct  st_data_s *st_gdata = tty->disc_data;
 758
 759        pr_info("%s ", __func__);
 760
 761        /*
 762         * TODO:
 763         * if a protocol has been registered & line discipline
 764         * un-installed for some reason - what should be done ?
 765         */
 766        spin_lock_irqsave(&st_gdata->lock, flags);
 767        for (i = ST_BT; i < ST_MAX_CHANNELS; i++) {
 768                if (st_gdata->is_registered[i] == true)
 769                        pr_err("%d not un-registered", i);
 770                st_gdata->list[i] = NULL;
 771                st_gdata->is_registered[i] = false;
 772        }
 773        st_gdata->protos_registered = 0;
 774        spin_unlock_irqrestore(&st_gdata->lock, flags);
 775        /*
 776         * signal to UIM via KIM that -
 777         * N_TI_WL ldisc is un-installed
 778         */
 779        st_kim_complete(st_gdata->kim_data);
 780        st_gdata->tty = NULL;
 781        /* Flush any pending characters in the driver and discipline. */
 782        tty_ldisc_flush(tty);
 783        tty_driver_flush_buffer(tty);
 784
 785        spin_lock_irqsave(&st_gdata->lock, flags);
 786        /* empty out txq and tx_waitq */
 787        skb_queue_purge(&st_gdata->txq);
 788        skb_queue_purge(&st_gdata->tx_waitq);
 789        /* reset the TTY Rx states of ST */
 790        st_gdata->rx_count = 0;
 791        st_gdata->rx_state = ST_W4_PACKET_TYPE;
 792        kfree_skb(st_gdata->rx_skb);
 793        st_gdata->rx_skb = NULL;
 794        spin_unlock_irqrestore(&st_gdata->lock, flags);
 795
 796        pr_debug("%s: done ", __func__);
 797}
 798
 799static void st_tty_receive(struct tty_struct *tty, const unsigned char *data,
 800                           const char *tty_flags, int count)
 801{
 802#ifdef VERBOSE
 803        print_hex_dump(KERN_DEBUG, ">in>", DUMP_PREFIX_NONE,
 804                16, 1, data, count, 0);
 805#endif
 806
 807        /*
 808         * if fw download is in progress then route incoming data
 809         * to KIM for validation
 810         */
 811        st_recv(tty->disc_data, data, count);
 812        pr_debug("done %s", __func__);
 813}
 814
 815/*
 816 * wake-up function called in from the TTY layer
 817 * inside the internal wakeup function will be called
 818 */
 819static void st_tty_wakeup(struct tty_struct *tty)
 820{
 821        struct  st_data_s *st_gdata = tty->disc_data;
 822        pr_debug("%s ", __func__);
 823        /* don't do an wakeup for now */
 824        clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
 825
 826        /*
 827         * schedule the internal wakeup instead of calling directly to
 828         * avoid lockup (port->lock needed in tty->ops->write is
 829         * already taken here
 830         */
 831        schedule_work(&st_gdata->work_write_wakeup);
 832}
 833
 834static void st_tty_flush_buffer(struct tty_struct *tty)
 835{
 836        struct  st_data_s *st_gdata = tty->disc_data;
 837        pr_debug("%s ", __func__);
 838
 839        kfree_skb(st_gdata->tx_skb);
 840        st_gdata->tx_skb = NULL;
 841
 842        tty_driver_flush_buffer(tty);
 843        return;
 844}
 845
 846static struct tty_ldisc_ops st_ldisc_ops = {
 847        .num = N_TI_WL,
 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(&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 = -ENOMEM;
 875                goto err_unreg_ldisc;
 876        }
 877
 878        /* Initialize ST TxQ and Tx waitQ queue head. All BT/FM/GPS module skb's
 879         * will be pushed in this queue for actual transmission.
 880         */
 881        skb_queue_head_init(&st_gdata->txq);
 882        skb_queue_head_init(&st_gdata->tx_waitq);
 883
 884        /* Locking used in st_int_enqueue() to avoid multiple execution */
 885        spin_lock_init(&st_gdata->lock);
 886
 887        err = st_ll_init(st_gdata);
 888        if (err) {
 889                pr_err("error during st_ll initialization(%ld)", err);
 890                goto err_free_gdata;
 891        }
 892
 893        INIT_WORK(&st_gdata->work_write_wakeup, work_fn_write_wakeup);
 894
 895        *core_data = st_gdata;
 896        return 0;
 897err_free_gdata:
 898        kfree(st_gdata);
 899err_unreg_ldisc:
 900        tty_unregister_ldisc(&st_ldisc_ops);
 901        return err;
 902}
 903
 904void st_core_exit(struct st_data_s *st_gdata)
 905{
 906        long err;
 907        /* internal module cleanup */
 908        err = st_ll_deinit(st_gdata);
 909        if (err)
 910                pr_err("error during deinit of ST LL %ld", err);
 911
 912        if (st_gdata != NULL) {
 913                /* Free ST Tx Qs and skbs */
 914                skb_queue_purge(&st_gdata->txq);
 915                skb_queue_purge(&st_gdata->tx_waitq);
 916                kfree_skb(st_gdata->rx_skb);
 917                kfree_skb(st_gdata->tx_skb);
 918                /* TTY ldisc cleanup */
 919                tty_unregister_ldisc(&st_ldisc_ops);
 920                /* free the global data pointer */
 921                kfree(st_gdata);
 922        }
 923}
 924