drivers/net/caif/caif_hsi.c

   1 /*
   2  * Copyright (C) ST-Ericsson AB 2010
   3  * Contact: Sjur Brendeland / sjur.brandeland@stericsson.com
   4  * Author:  Daniel Martensson / daniel.martensson@stericsson.com
   5  *          Dmitry.Tarnyagin  / dmitry.tarnyagin@stericsson.com
   6  * License terms: GNU General Public License (GPL) version 2.
   7  */
   8
   9 #include <linux/init.h>
  10 #include <linux/module.h>
  11 #include <linux/device.h>
  12 #include <linux/platform_device.h>
  13 #include <linux/netdevice.h>
  14 #include <linux/string.h>
  15 #include <linux/list.h>
  16 #include <linux/interrupt.h>
  17 #include <linux/delay.h>
  18 #include <linux/sched.h>
  19 #include <linux/if_arp.h>
  20 #include <linux/timer.h>
  21 #include <linux/rtnetlink.h>
  22 #include <net/caif/caif_layer.h>
  23 #include <net/caif/caif_hsi.h>
  24
  25 MODULE_LICENSE("GPL");
  26 MODULE_AUTHOR("Daniel Martensson<daniel.martensson@stericsson.com>");
  27 MODULE_DESCRIPTION("CAIF HSI driver");
  28
  29 /* Returns the number of padding bytes for alignment. */
  30 #define PAD_POW2(x, pow) ((((x)&((pow)-1)) == 0) ? 0 :\
  31                                 (((pow)-((x)&((pow)-1)))))
  32
  33 static int inactivity_timeout = 1000;
  34 module_param(inactivity_timeout, int, S_IRUGO | S_IWUSR);
  35 MODULE_PARM_DESC(inactivity_timeout, "Inactivity timeout on HSI, ms.");
  36
  37 /*
  38  * HSI padding options.
  39  * Warning: must be a base of 2 (& operation used) and can not be zero !
  40  */
  41 static int hsi_head_align = 4;
  42 module_param(hsi_head_align, int, S_IRUGO);
  43 MODULE_PARM_DESC(hsi_head_align, "HSI head alignment.");
  44
  45 static int hsi_tail_align = 4;
  46 module_param(hsi_tail_align, int, S_IRUGO);
  47 MODULE_PARM_DESC(hsi_tail_align, "HSI tail alignment.");
  48
  49 /*
  50  * HSI link layer flowcontrol thresholds.
  51  * Warning: A high threshold value migth increase throughput but it will at
  52  * the same time prevent channel prioritization and increase the risk of
  53  * flooding the modem. The high threshold should be above the low.
  54  */
  55 static int hsi_high_threshold = 100;
  56 module_param(hsi_high_threshold, int, S_IRUGO);
  57 MODULE_PARM_DESC(hsi_high_threshold, "HSI high threshold (FLOW OFF).");
  58
  59 static int hsi_low_threshold = 50;
  60 module_param(hsi_low_threshold, int, S_IRUGO);
  61 MODULE_PARM_DESC(hsi_low_threshold, "HSI high threshold (FLOW ON).");
  62
  63 #define ON 1
  64 #define OFF 0
  65
  66 /*
  67  * Threshold values for the HSI packet queue. Flowcontrol will be asserted
  68  * when the number of packets exceeds HIGH_WATER_MARK. It will not be
  69  * de-asserted before the number of packets drops below LOW_WATER_MARK.
  70  */
  71 #define LOW_WATER_MARK   hsi_low_threshold
  72 #define HIGH_WATER_MARK  hsi_high_threshold
  73
  74 static LIST_HEAD(cfhsi_list);
  75 static spinlock_t cfhsi_list_lock;
  76
  77 static void cfhsi_inactivity_tout(unsigned long arg)
  78 {
  79         struct cfhsi *cfhsi = (struct cfhsi *)arg;
  80
  81         dev_dbg(&cfhsi->ndev->dev, "%s.\n",
  82                 __func__);
  83
  84         /* Schedule power down work queue. */
  85         if (!test_bit(CFHSI_SHUTDOWN, &cfhsi->bits))
  86                 queue_work(cfhsi->wq, &cfhsi->wake_down_work);
  87 }
  88
  89 static void cfhsi_abort_tx(struct cfhsi *cfhsi)
  90 {
  91         struct sk_buff *skb;
  92
  93         for (;;) {
  94                 spin_lock_bh(&cfhsi->lock);
  95                 skb = skb_dequeue(&cfhsi->qhead);
  96                 if (!skb)
  97                         break;
  98
  99                 cfhsi->ndev->stats.tx_errors++;
 100                 cfhsi->ndev->stats.tx_dropped++;
 101                 spin_unlock_bh(&cfhsi->lock);
 102                 kfree_skb(skb);
 103         }
 104         cfhsi->tx_state = CFHSI_TX_STATE_IDLE;
 105         if (!test_bit(CFHSI_SHUTDOWN, &cfhsi->bits))
 106                 mod_timer(&cfhsi->timer,
 107                         jiffies + cfhsi->inactivity_timeout);
 108         spin_unlock_bh(&cfhsi->lock);
 109 }
 110
 111 static int cfhsi_flush_fifo(struct cfhsi *cfhsi)
 112 {
 113         char buffer[32]; /* Any reasonable value */
 114         size_t fifo_occupancy;
 115         int ret;
 116
 117         dev_dbg(&cfhsi->ndev->dev, "%s.\n",
 118                 __func__);
 119
 120         do {
 121                 ret = cfhsi->dev->cfhsi_fifo_occupancy(cfhsi->dev,
 122                                 &fifo_occupancy);
 123                 if (ret) {
 124                         dev_warn(&cfhsi->ndev->dev,
 125                                 "%s: can't get FIFO occupancy: %d.\n",
 126                                 __func__, ret);
 127                         break;
 128                 } else if (!fifo_occupancy)
 129                         /* No more data, exitting normally */
 130                         break;
 131
 132                 fifo_occupancy = min(sizeof(buffer), fifo_occupancy);
 133                 set_bit(CFHSI_FLUSH_FIFO, &cfhsi->bits);
 134                 ret = cfhsi->dev->cfhsi_rx(buffer, fifo_occupancy,
 135                                 cfhsi->dev);
 136                 if (ret) {
 137                         clear_bit(CFHSI_FLUSH_FIFO, &cfhsi->bits);
 138                         dev_warn(&cfhsi->ndev->dev,
 139                                 "%s: can't read data: %d.\n",
 140                                 __func__, ret);
 141                         break;
 142                 }
 143
 144                 ret = 5 * HZ;
 145                 ret = wait_event_interruptible_timeout(cfhsi->flush_fifo_wait,
 146                          !test_bit(CFHSI_FLUSH_FIFO, &cfhsi->bits), ret);
 147
 148                 if (ret < 0) {
 149                         dev_warn(&cfhsi->ndev->dev,
 150                                 "%s: can't wait for flush complete: %d.\n",
 151                                 __func__, ret);
 152                         break;
 153                 } else if (!ret) {
 154                         ret = -ETIMEDOUT;
 155                         dev_warn(&cfhsi->ndev->dev,
 156                                 "%s: timeout waiting for flush complete.\n",
 157                                 __func__);
 158                         break;
 159                 }
 160         } while (1);
 161
 162         return ret;
 163 }
 164
 165 static int cfhsi_tx_frm(struct cfhsi_desc *desc, struct cfhsi *cfhsi)
 166 {
 167         int nfrms = 0;
 168         int pld_len = 0;
 169         struct sk_buff *skb;
 170         u8 *pfrm = desc->emb_frm + CFHSI_MAX_EMB_FRM_SZ;
 171
 172         skb = skb_dequeue(&cfhsi->qhead);
 173         if (!skb)
 174                 return 0;
 175
 176         /* Clear offset. */
 177         desc->offset = 0;
 178
 179         /* Check if we can embed a CAIF frame. */
 180         if (skb->len < CFHSI_MAX_EMB_FRM_SZ) {
 181                 struct caif_payload_info *info;
 182                 int hpad = 0;
 183                 int tpad = 0;
 184
 185                 /* Calculate needed head alignment and tail alignment. */
 186                 info = (struct caif_payload_info *)&skb->cb;
 187
 188                 hpad = 1 + PAD_POW2((info->hdr_len + 1), hsi_head_align);
 189                 tpad = PAD_POW2((skb->len + hpad), hsi_tail_align);
 190
 191                 /* Check if frame still fits with added alignment. */
 192                 if ((skb->len + hpad + tpad) <= CFHSI_MAX_EMB_FRM_SZ) {
 193                         u8 *pemb = desc->emb_frm;
 194                         desc->offset = CFHSI_DESC_SHORT_SZ;
 195                         *pemb = (u8)(hpad - 1);
 196                         pemb += hpad;
 197
 198                         /* Update network statistics. */
 199                         cfhsi->ndev->stats.tx_packets++;
 200                         cfhsi->ndev->stats.tx_bytes += skb->len;
 201
 202                         /* Copy in embedded CAIF frame. */
 203                         skb_copy_bits(skb, 0, pemb, skb->len);
 204                         consume_skb(skb);
 205                         skb = NULL;
 206                 }
 207         }
 208
 209         /* Create payload CAIF frames. */
 210         pfrm = desc->emb_frm + CFHSI_MAX_EMB_FRM_SZ;
 211         while (nfrms < CFHSI_MAX_PKTS) {
 212                 struct caif_payload_info *info;
 213                 int hpad = 0;
 214                 int tpad = 0;
 215
 216                 if (!skb)
 217                         skb = skb_dequeue(&cfhsi->qhead);
 218
 219                 if (!skb)
 220                         break;
 221
 222                 /* Calculate needed head alignment and tail alignment. */
 223                 info = (struct caif_payload_info *)&skb->cb;
 224
 225                 hpad = 1 + PAD_POW2((info->hdr_len + 1), hsi_head_align);
 226                 tpad = PAD_POW2((skb->len + hpad), hsi_tail_align);
 227
 228                 /* Fill in CAIF frame length in descriptor. */
 229                 desc->cffrm_len[nfrms] = hpad + skb->len + tpad;
 230
 231                 /* Fill head padding information. */
 232                 *pfrm = (u8)(hpad - 1);
 233                 pfrm += hpad;
 234
 235                 /* Update network statistics. */
 236                 cfhsi->ndev->stats.tx_packets++;
 237                 cfhsi->ndev->stats.tx_bytes += skb->len;
 238
 239                 /* Copy in CAIF frame. */
 240                 skb_copy_bits(skb, 0, pfrm, skb->len);
 241
 242                 /* Update payload length. */
 243                 pld_len += desc->cffrm_len[nfrms];
 244
 245                 /* Update frame pointer. */
 246                 pfrm += skb->len + tpad;
 247                 consume_skb(skb);
 248                 skb = NULL;
 249
 250                 /* Update number of frames. */
 251                 nfrms++;
 252         }
 253
 254         /* Unused length fields should be zero-filled (according to SPEC). */
 255         while (nfrms < CFHSI_MAX_PKTS) {
 256                 desc->cffrm_len[nfrms] = 0x0000;
 257                 nfrms++;
 258         }
 259
 260         /* Check if we can piggy-back another descriptor. */
 261         skb = skb_peek(&cfhsi->qhead);
 262         if (skb)
 263                 desc->header |= CFHSI_PIGGY_DESC;
 264         else
 265                 desc->header &= ~CFHSI_PIGGY_DESC;
 266
 267         return CFHSI_DESC_SZ + pld_len;
 268 }
 269
 270 static void cfhsi_tx_done(struct cfhsi *cfhsi)
 271 {
 272         struct cfhsi_desc *desc = NULL;
 273         int len = 0;
 274         int res;
 275
 276         dev_dbg(&cfhsi->ndev->dev, "%s.\n", __func__);
 277
 278         if (test_bit(CFHSI_SHUTDOWN, &cfhsi->bits))
 279                 return;
 280
 281         desc = (struct cfhsi_desc *)cfhsi->tx_buf;
 282
 283         do {
 284                 /*
 285                  * Send flow on if flow off has been previously signalled
 286                  * and number of packets is below low water mark.
 287                  */
 288                 spin_lock_bh(&cfhsi->lock);
 289                 if (cfhsi->flow_off_sent &&
 290                                 cfhsi->qhead.qlen <= cfhsi->q_low_mark &&
 291                                 cfhsi->cfdev.flowctrl) {
 292
 293                         cfhsi->flow_off_sent = 0;
 294                         cfhsi->cfdev.flowctrl(cfhsi->ndev, ON);
 295                 }
 296                 spin_unlock_bh(&cfhsi->lock);
 297
 298                 /* Create HSI frame. */
 299                 do {
 300                         len = cfhsi_tx_frm(desc, cfhsi);
 301                         if (!len) {
 302                                 spin_lock_bh(&cfhsi->lock);
 303                                 if (unlikely(skb_peek(&cfhsi->qhead))) {
 304                                         spin_unlock_bh(&cfhsi->lock);
 305                                         continue;
 306                                 }
 307                                 cfhsi->tx_state = CFHSI_TX_STATE_IDLE;
 308                                 /* Start inactivity timer. */
 309                                 mod_timer(&cfhsi->timer,
 310                                         jiffies + cfhsi->inactivity_timeout);
 311                                 spin_unlock_bh(&cfhsi->lock);
 312                                 goto done;
 313                         }
 314                 } while (!len);
 315
 316                 /* Set up new transfer. */
 317                 res = cfhsi->dev->cfhsi_tx(cfhsi->tx_buf, len, cfhsi->dev);
 318                 if (WARN_ON(res < 0)) {
 319                         dev_err(&cfhsi->ndev->dev, "%s: TX error %d.\n",
 320                                 __func__, res);
 321                 }
 322         } while (res < 0);
 323
 324 done:
 325         return;
 326 }
 327
 328 static void cfhsi_tx_done_cb(struct cfhsi_drv *drv)
 329 {
 330         struct cfhsi *cfhsi;
 331
 332         cfhsi = container_of(drv, struct cfhsi, drv);
 333         dev_dbg(&cfhsi->ndev->dev, "%s.\n",
 334                 __func__);
 335
 336         if (test_bit(CFHSI_SHUTDOWN, &cfhsi->bits))
 337                 return;
 338         cfhsi_tx_done(cfhsi);
 339 }
 340
 341 static int cfhsi_rx_desc(struct cfhsi_desc *desc, struct cfhsi *cfhsi)
 342 {
 343         int xfer_sz = 0;
 344         int nfrms = 0;
 345         u16 *plen = NULL;
 346         u8 *pfrm = NULL;
 347
 348         if ((desc->header & ~CFHSI_PIGGY_DESC) ||
 349                         (desc->offset > CFHSI_MAX_EMB_FRM_SZ)) {
 350                 dev_err(&cfhsi->ndev->dev, "%s: Invalid descriptor.\n",
 351                         __func__);
 352                 return -EPROTO;
 353         }
 354
 355         /* Check for embedded CAIF frame. */
 356         if (desc->offset) {
 357                 struct sk_buff *skb;
 358                 u8 *dst = NULL;
 359                 int len = 0;
 360                 pfrm = ((u8 *)desc) + desc->offset;
 361
 362                 /* Remove offset padding. */
 363                 pfrm += *pfrm + 1;
 364
 365                 /* Read length of CAIF frame (little endian). */
 366                 len = *pfrm;
 367                 len |= ((*(pfrm+1)) << 8) & 0xFF00;
 368                 len += 2;       /* Add FCS fields. */
 369
 370                 /* Sanity check length of CAIF frame. */
 371                 if (unlikely(len > CFHSI_MAX_CAIF_FRAME_SZ)) {
 372                         dev_err(&cfhsi->ndev->dev, "%s: Invalid length.\n",
 373                                 __func__);
 374                         return -EPROTO;
 375                 }
 376
 377                 /* Allocate SKB (OK even in IRQ context). */
 378                 skb = alloc_skb(len + 1, GFP_ATOMIC);
 379                 if (!skb) {
 380                         dev_err(&cfhsi->ndev->dev, "%s: Out of memory !\n",
 381                                 __func__);
 382                         return -ENOMEM;
 383                 }
 384                 caif_assert(skb != NULL);
 385
 386                 dst = skb_put(skb, len);
 387                 memcpy(dst, pfrm, len);
 388
 389                 skb->protocol = htons(ETH_P_CAIF);
 390                 skb_reset_mac_header(skb);
 391                 skb->dev = cfhsi->ndev;
 392
 393                 /*
 394                  * We are called from a arch specific platform device.
 395                  * Unfortunately we don't know what context we're
 396                  * running in.
 397                  */
 398                 if (in_interrupt())
 399                         netif_rx(skb);
 400                 else
 401                         netif_rx_ni(skb);
 402
 403                 /* Update network statistics. */
 404                 cfhsi->ndev->stats.rx_packets++;
 405                 cfhsi->ndev->stats.rx_bytes += len;
 406         }
 407
 408         /* Calculate transfer length. */
 409         plen = desc->cffrm_len;
 410         while (nfrms < CFHSI_MAX_PKTS && *plen) {
 411                 xfer_sz += *plen;
 412                 plen++;
 413                 nfrms++;
 414         }
 415
 416         /* Check for piggy-backed descriptor. */
 417         if (desc->header & CFHSI_PIGGY_DESC)
 418                 xfer_sz += CFHSI_DESC_SZ;
 419
 420         if ((xfer_sz % 4) || (xfer_sz > (CFHSI_BUF_SZ_RX - CFHSI_DESC_SZ))) {
 421                 dev_err(&cfhsi->ndev->dev,
 422                                 "%s: Invalid payload len: %d, ignored.\n",
 423                         __func__, xfer_sz);
 424                 return -EPROTO;
 425         }
 426         return xfer_sz;
 427 }
 428
 429 static int cfhsi_rx_pld(struct cfhsi_desc *desc, struct cfhsi *cfhsi)
 430 {
 431         int rx_sz = 0;
 432         int nfrms = 0;
 433         u16 *plen = NULL;
 434         u8 *pfrm = NULL;
 435
 436         /* Sanity check header and offset. */
 437         if (WARN_ON((desc->header & ~CFHSI_PIGGY_DESC) ||
 438                         (desc->offset > CFHSI_MAX_EMB_FRM_SZ))) {
 439                 dev_err(&cfhsi->ndev->dev, "%s: Invalid descriptor.\n",
 440                         __func__);
 441                 return -EPROTO;
 442         }
 443
 444         /* Set frame pointer to start of payload. */
 445         pfrm = desc->emb_frm + CFHSI_MAX_EMB_FRM_SZ;
 446         plen = desc->cffrm_len;
 447
 448         /* Skip already processed frames. */
 449         while (nfrms < cfhsi->rx_state.nfrms) {
 450                 pfrm += *plen;
 451                 rx_sz += *plen;
 452                 plen++;
 453                 nfrms++;
 454         }
 455
 456         /* Parse payload. */
 457         while (nfrms < CFHSI_MAX_PKTS && *plen) {
 458                 struct sk_buff *skb;
 459                 u8 *dst = NULL;
 460                 u8 *pcffrm = NULL;
 461                 int len = 0;
 462
 463                 /* CAIF frame starts after head padding. */
 464                 pcffrm = pfrm + *pfrm + 1;
 465
 466                 /* Read length of CAIF frame (little endian). */
 467                 len = *pcffrm;
 468                 len |= ((*(pcffrm + 1)) << 8) & 0xFF00;
 469                 len += 2;       /* Add FCS fields. */
 470
 471                 /* Sanity check length of CAIF frames. */
 472                 if (unlikely(len > CFHSI_MAX_CAIF_FRAME_SZ)) {
 473                         dev_err(&cfhsi->ndev->dev, "%s: Invalid length.\n",
 474                                 __func__);
 475                         return -EPROTO;
 476                 }
 477
 478                 /* Allocate SKB (OK even in IRQ context). */
 479                 skb = alloc_skb(len + 1, GFP_ATOMIC);
 480                 if (!skb) {
 481                         dev_err(&cfhsi->ndev->dev, "%s: Out of memory !\n",
 482                                 __func__);
 483                         cfhsi->rx_state.nfrms = nfrms;
 484                         return -ENOMEM;
 485                 }
 486                 caif_assert(skb != NULL);
 487
 488                 dst = skb_put(skb, len);
 489                 memcpy(dst, pcffrm, len);
 490
 491                 skb->protocol = htons(ETH_P_CAIF);
 492                 skb_reset_mac_header(skb);
 493                 skb->dev = cfhsi->ndev;
 494
 495                 /*
 496                  * We're called from a platform device,
 497                  * and don't know the context we're running in.
 498                  */
 499                 if (in_interrupt())
 500                         netif_rx(skb);
 501                 else
 502                         netif_rx_ni(skb);
 503
 504                 /* Update network statistics. */
 505                 cfhsi->ndev->stats.rx_packets++;
 506                 cfhsi->ndev->stats.rx_bytes += len;
 507
 508                 pfrm += *plen;
 509                 rx_sz += *plen;
 510                 plen++;
 511                 nfrms++;
 512         }
 513
 514         return rx_sz;
 515 }
 516
 517 static void cfhsi_rx_done(struct cfhsi *cfhsi)
 518 {
 519         int res;
 520         int desc_pld_len = 0;
 521         struct cfhsi_desc *desc = NULL;
 522
 523         desc = (struct cfhsi_desc *)cfhsi->rx_buf;
 524
 525         dev_dbg(&cfhsi->ndev->dev, "%s\n", __func__);
 526
 527         if (test_bit(CFHSI_SHUTDOWN, &cfhsi->bits))
 528                 return;
 529
 530         /* Update inactivity timer if pending. */
 531         spin_lock_bh(&cfhsi->lock);
 532         mod_timer_pending(&cfhsi->timer,
 533                         jiffies + cfhsi->inactivity_timeout);
 534         spin_unlock_bh(&cfhsi->lock);
 535
 536         if (cfhsi->rx_state.state == CFHSI_RX_STATE_DESC) {
 537                 desc_pld_len = cfhsi_rx_desc(desc, cfhsi);
 538                 if (desc_pld_len == -ENOMEM)
 539                         goto restart;
 540                 if (desc_pld_len == -EPROTO)
 541                         goto out_of_sync;
 542         } else {
 543                 int pld_len;
 544
 545                 if (!cfhsi->rx_state.piggy_desc) {
 546                         pld_len = cfhsi_rx_pld(desc, cfhsi);
 547                         if (pld_len == -ENOMEM)
 548                                 goto restart;
 549                         if (pld_len == -EPROTO)
 550                                 goto out_of_sync;
 551                         cfhsi->rx_state.pld_len = pld_len;
 552                 } else {
 553                         pld_len = cfhsi->rx_state.pld_len;
 554                 }
 555
 556                 if ((pld_len > 0) && (desc->header & CFHSI_PIGGY_DESC)) {
 557                         struct cfhsi_desc *piggy_desc;
 558                         piggy_desc = (struct cfhsi_desc *)
 559                                 (desc->emb_frm + CFHSI_MAX_EMB_FRM_SZ +
 560                                                 pld_len);
 561                         cfhsi->rx_state.piggy_desc = true;
 562
 563                         /* Extract piggy-backed descriptor. */
 564                         desc_pld_len = cfhsi_rx_desc(piggy_desc, cfhsi);
 565                         if (desc_pld_len == -ENOMEM)
 566                                 goto restart;
 567
 568                         /*
 569                          * Copy needed information from the piggy-backed
 570                          * descriptor to the descriptor in the start.
 571                          */
 572                         memcpy((u8 *)desc, (u8 *)piggy_desc,
 573                                         CFHSI_DESC_SHORT_SZ);
 574
 575                         if (desc_pld_len == -EPROTO)
 576                                 goto out_of_sync;
 577                 }
 578         }
 579
 580         memset(&cfhsi->rx_state, 0, sizeof(cfhsi->rx_state));
 581         if (desc_pld_len) {
 582                 cfhsi->rx_state.state = CFHSI_RX_STATE_PAYLOAD;
 583                 cfhsi->rx_ptr = cfhsi->rx_buf + CFHSI_DESC_SZ;
 584                 cfhsi->rx_len = desc_pld_len;
 585         } else {
 586                 cfhsi->rx_state.state = CFHSI_RX_STATE_DESC;
 587                 cfhsi->rx_ptr = cfhsi->rx_buf;
 588                 cfhsi->rx_len = CFHSI_DESC_SZ;
 589         }
 590
 591         if (test_bit(CFHSI_AWAKE, &cfhsi->bits)) {
 592                 /* Set up new transfer. */
 593                 dev_dbg(&cfhsi->ndev->dev, "%s: Start RX.\n",
 594                         __func__);
 595                 res = cfhsi->dev->cfhsi_rx(cfhsi->rx_ptr, cfhsi->rx_len,
 596                                 cfhsi->dev);
 597                 if (WARN_ON(res < 0)) {
 598                         dev_err(&cfhsi->ndev->dev, "%s: RX error %d.\n",
 599                                 __func__, res);
 600                         cfhsi->ndev->stats.rx_errors++;
 601                         cfhsi->ndev->stats.rx_dropped++;
 602                 }
 603         }
 604         return;
 605
 606 restart:
 607         if (++cfhsi->rx_state.retries > CFHSI_MAX_RX_RETRIES) {
 608                 dev_err(&cfhsi->ndev->dev, "%s: No memory available "
 609                         "in %d iterations.\n",
 610                         __func__, CFHSI_MAX_RX_RETRIES);
 611                 BUG();
 612         }
 613         mod_timer(&cfhsi->rx_slowpath_timer, jiffies + 1);
 614         return;
 615
 616 out_of_sync:
 617         dev_err(&cfhsi->ndev->dev, "%s: Out of sync.\n", __func__);
 618         print_hex_dump_bytes("--> ", DUMP_PREFIX_NONE,
 619                         cfhsi->rx_buf, CFHSI_DESC_SZ);
 620         schedule_work(&cfhsi->out_of_sync_work);
 621 }
 622
 623 static void cfhsi_rx_slowpath(unsigned long arg)
 624 {
 625         struct cfhsi *cfhsi = (struct cfhsi *)arg;
 626
 627         dev_dbg(&cfhsi->ndev->dev, "%s.\n",
 628                 __func__);
 629
 630         cfhsi_rx_done(cfhsi);
 631 }
 632
 633 static void cfhsi_rx_done_cb(struct cfhsi_drv *drv)
 634 {
 635         struct cfhsi *cfhsi;
 636
 637         cfhsi = container_of(drv, struct cfhsi, drv);
 638         dev_dbg(&cfhsi->ndev->dev, "%s.\n",
 639                 __func__);
 640
 641         if (test_bit(CFHSI_SHUTDOWN, &cfhsi->bits))
 642                 return;
 643
 644         if (test_and_clear_bit(CFHSI_FLUSH_FIFO, &cfhsi->bits))
 645                 wake_up_interruptible(&cfhsi->flush_fifo_wait);
 646         else
 647                 cfhsi_rx_done(cfhsi);
 648 }
 649
 650 static void cfhsi_wake_up(struct work_struct *work)
 651 {
 652         struct cfhsi *cfhsi = NULL;
 653         int res;
 654         int len;
 655         long ret;
 656
 657         cfhsi = container_of(work, struct cfhsi, wake_up_work);
 658
 659         if (test_bit(CFHSI_SHUTDOWN, &cfhsi->bits))
 660                 return;
 661
 662         if (unlikely(test_bit(CFHSI_AWAKE, &cfhsi->bits))) {
 663                 /* It happenes when wakeup is requested by
 664                  * both ends at the same time. */
 665                 clear_bit(CFHSI_WAKE_UP, &cfhsi->bits);
 666                 clear_bit(CFHSI_WAKE_UP_ACK, &cfhsi->bits);
 667                 return;
 668         }
 669
 670         /* Activate wake line. */
 671         cfhsi->dev->cfhsi_wake_up(cfhsi->dev);
 672
 673         dev_dbg(&cfhsi->ndev->dev, "%s: Start waiting.\n",
 674                 __func__);
 675
 676         /* Wait for acknowledge. */
 677         ret = CFHSI_WAKE_TOUT;
 678         ret = wait_event_interruptible_timeout(cfhsi->wake_up_wait,
 679                                         test_and_clear_bit(CFHSI_WAKE_UP_ACK,
 680                                                         &cfhsi->bits), ret);
 681         if (unlikely(ret < 0)) {
 682                 /* Interrupted by signal. */
 683                 dev_err(&cfhsi->ndev->dev, "%s: Signalled: %ld.\n",
 684                         __func__, ret);
 685
 686                 clear_bit(CFHSI_WAKE_UP, &cfhsi->bits);
 687                 cfhsi->dev->cfhsi_wake_down(cfhsi->dev);
 688                 return;
 689         } else if (!ret) {
 690                 bool ca_wake = false;
 691                 size_t fifo_occupancy = 0;
 692
 693                 /* Wakeup timeout */
 694                 dev_err(&cfhsi->ndev->dev, "%s: Timeout.\n",
 695                         __func__);
 696
 697                 /* Check FIFO to check if modem has sent something. */
 698                 WARN_ON(cfhsi->dev->cfhsi_fifo_occupancy(cfhsi->dev,
 699                                         &fifo_occupancy));
 700
 701                 dev_err(&cfhsi->ndev->dev, "%s: Bytes in FIFO: %u.\n",
 702                                 __func__, (unsigned) fifo_occupancy);
 703
 704                 /* Check if we misssed the interrupt. */
 705                 WARN_ON(cfhsi->dev->cfhsi_get_peer_wake(cfhsi->dev,
 706                                                         &ca_wake));
 707
 708                 if (ca_wake) {
 709                         dev_err(&cfhsi->ndev->dev, "%s: CA Wake missed !.\n",
 710                                 __func__);
 711
 712                         /* Clear the CFHSI_WAKE_UP_ACK bit to prevent race. */
 713                         clear_bit(CFHSI_WAKE_UP_ACK, &cfhsi->bits);
 714
 715                         /* Continue execution. */
 716                         goto wake_ack;
 717                 }
 718
 719                 clear_bit(CFHSI_WAKE_UP, &cfhsi->bits);
 720                 cfhsi->dev->cfhsi_wake_down(cfhsi->dev);
 721                 return;
 722         }
 723 wake_ack:
 724         dev_dbg(&cfhsi->ndev->dev, "%s: Woken.\n",
 725                 __func__);
 726
 727         /* Clear power up bit. */
 728         set_bit(CFHSI_AWAKE, &cfhsi->bits);
 729         clear_bit(CFHSI_WAKE_UP, &cfhsi->bits);
 730
 731         /* Resume read operation. */
 732         dev_dbg(&cfhsi->ndev->dev, "%s: Start RX.\n", __func__);
 733         res = cfhsi->dev->cfhsi_rx(cfhsi->rx_ptr, cfhsi->rx_len, cfhsi->dev);
 734
 735         if (WARN_ON(res < 0))
 736                 dev_err(&cfhsi->ndev->dev, "%s: RX err %d.\n", __func__, res);
 737
 738         /* Clear power up acknowledment. */
 739         clear_bit(CFHSI_WAKE_UP_ACK, &cfhsi->bits);
 740
 741         spin_lock_bh(&cfhsi->lock);
 742
 743         /* Resume transmit if queue is not empty. */
 744         if (!skb_peek(&cfhsi->qhead)) {
 745                 dev_dbg(&cfhsi->ndev->dev, "%s: Peer wake, start timer.\n",
 746                         __func__);
 747                 /* Start inactivity timer. */
 748                 mod_timer(&cfhsi->timer,
 749                                 jiffies + cfhsi->inactivity_timeout);
 750                 spin_unlock_bh(&cfhsi->lock);
 751                 return;
 752         }
 753
 754         dev_dbg(&cfhsi->ndev->dev, "%s: Host wake.\n",
 755                 __func__);
 756
 757         spin_unlock_bh(&cfhsi->lock);
 758
 759         /* Create HSI frame. */
 760         len = cfhsi_tx_frm((struct cfhsi_desc *)cfhsi->tx_buf, cfhsi);
 761
 762         if (likely(len > 0)) {
 763                 /* Set up new transfer. */
 764                 res = cfhsi->dev->cfhsi_tx(cfhsi->tx_buf, len, cfhsi->dev);
 765                 if (WARN_ON(res < 0)) {
 766                         dev_err(&cfhsi->ndev->dev, "%s: TX error %d.\n",
 767                                 __func__, res);
 768                         cfhsi_abort_tx(cfhsi);
 769                 }
 770         } else {
 771                 dev_err(&cfhsi->ndev->dev,
 772                                 "%s: Failed to create HSI frame: %d.\n",
 773                                 __func__, len);
 774         }
 775 }
 776
 777 static void cfhsi_wake_down(struct work_struct *work)
 778 {
 779         long ret;
 780         struct cfhsi *cfhsi = NULL;
 781         size_t fifo_occupancy = 0;
 782         int retry = CFHSI_WAKE_TOUT;
 783
 784         cfhsi = container_of(work, struct cfhsi, wake_down_work);
 785         dev_dbg(&cfhsi->ndev->dev, "%s.\n", __func__);
 786
 787         if (test_bit(CFHSI_SHUTDOWN, &cfhsi->bits))
 788                 return;
 789
 790         /* Deactivate wake line. */
 791         cfhsi->dev->cfhsi_wake_down(cfhsi->dev);
 792
 793         /* Wait for acknowledge. */
 794         ret = CFHSI_WAKE_TOUT;
 795         ret = wait_event_interruptible_timeout(cfhsi->wake_down_wait,
 796                                         test_and_clear_bit(CFHSI_WAKE_DOWN_ACK,
 797                                                         &cfhsi->bits), ret);
 798         if (ret < 0) {
 799                 /* Interrupted by signal. */
 800                 dev_err(&cfhsi->ndev->dev, "%s: Signalled: %ld.\n",
 801                         __func__, ret);
 802                 return;
 803         } else if (!ret) {
 804                 bool ca_wake = true;
 805
 806                 /* Timeout */
 807                 dev_err(&cfhsi->ndev->dev, "%s: Timeout.\n", __func__);
 808
 809                 /* Check if we misssed the interrupt. */
 810                 WARN_ON(cfhsi->dev->cfhsi_get_peer_wake(cfhsi->dev,
 811                                                         &ca_wake));
 812                 if (!ca_wake)
 813                         dev_err(&cfhsi->ndev->dev, "%s: CA Wake missed !.\n",
 814                                 __func__);
 815         }
 816
 817         /* Check FIFO occupancy. */
 818         while (retry) {
 819                 WARN_ON(cfhsi->dev->cfhsi_fifo_occupancy(cfhsi->dev,
 820                                                         &fifo_occupancy));
 821
 822                 if (!fifo_occupancy)
 823                         break;
 824
 825                 set_current_state(TASK_INTERRUPTIBLE);
 826                 schedule_timeout(1);
 827                 retry--;
 828         }
 829
 830         if (!retry)
 831                 dev_err(&cfhsi->ndev->dev, "%s: FIFO Timeout.\n", __func__);
 832
 833         /* Clear AWAKE condition. */
 834         clear_bit(CFHSI_AWAKE, &cfhsi->bits);
 835
 836         /* Cancel pending RX requests. */
 837         cfhsi->dev->cfhsi_rx_cancel(cfhsi->dev);
 838
 839 }
 840
 841 static void cfhsi_out_of_sync(struct work_struct *work)
 842 {
 843         struct cfhsi *cfhsi = NULL;
 844
 845         cfhsi = container_of(work, struct cfhsi, out_of_sync_work);
 846
 847         rtnl_lock();
 848         dev_close(cfhsi->ndev);
 849         rtnl_unlock();
 850 }
 851
 852 static void cfhsi_wake_up_cb(struct cfhsi_drv *drv)
 853 {
 854         struct cfhsi *cfhsi = NULL;
 855
 856         cfhsi = container_of(drv, struct cfhsi, drv);
 857         dev_dbg(&cfhsi->ndev->dev, "%s.\n",
 858                 __func__);
 859
 860         set_bit(CFHSI_WAKE_UP_ACK, &cfhsi->bits);
 861         wake_up_interruptible(&cfhsi->wake_up_wait);
 862
 863         if (test_bit(CFHSI_SHUTDOWN, &cfhsi->bits))
 864                 return;
 865
 866         /* Schedule wake up work queue if the peer initiates. */
 867         if (!test_and_set_bit(CFHSI_WAKE_UP, &cfhsi->bits))
 868                 queue_work(cfhsi->wq, &cfhsi->wake_up_work);
 869 }
 870
 871 static void cfhsi_wake_down_cb(struct cfhsi_drv *drv)
 872 {
 873         struct cfhsi *cfhsi = NULL;
 874
 875         cfhsi = container_of(drv, struct cfhsi, drv);
 876         dev_dbg(&cfhsi->ndev->dev, "%s.\n",
 877                 __func__);
 878
 879         /* Initiating low power is only permitted by the host (us). */
 880         set_bit(CFHSI_WAKE_DOWN_ACK, &cfhsi->bits);
 881         wake_up_interruptible(&cfhsi->wake_down_wait);
 882 }
 883
 884 static int cfhsi_xmit(struct sk_buff *skb, struct net_device *dev)
 885 {
 886         struct cfhsi *cfhsi = NULL;
 887         int start_xfer = 0;
 888         int timer_active;
 889
 890         if (!dev)
 891                 return -EINVAL;
 892
 893         cfhsi = netdev_priv(dev);
 894
 895         spin_lock_bh(&cfhsi->lock);
 896
 897         skb_queue_tail(&cfhsi->qhead, skb);
 898
 899         /* Sanity check; xmit should not be called after unregister_netdev */
 900         if (WARN_ON(test_bit(CFHSI_SHUTDOWN, &cfhsi->bits))) {
 901                 spin_unlock_bh(&cfhsi->lock);
 902                 cfhsi_abort_tx(cfhsi);
 903                 return -EINVAL;
 904         }
 905
 906         /* Send flow off if number of packets is above high water mark. */
 907         if (!cfhsi->flow_off_sent &&
 908                 cfhsi->qhead.qlen > cfhsi->q_high_mark &&
 909                 cfhsi->cfdev.flowctrl) {
 910                 cfhsi->flow_off_sent = 1;
 911                 cfhsi->cfdev.flowctrl(cfhsi->ndev, OFF);
 912         }
 913
 914         if (cfhsi->tx_state == CFHSI_TX_STATE_IDLE) {
 915                 cfhsi->tx_state = CFHSI_TX_STATE_XFER;
 916                 start_xfer = 1;
 917         }
 918
 919         if (!start_xfer) {
 920                 spin_unlock_bh(&cfhsi->lock);
 921                 return 0;
 922         }
 923
 924         /* Delete inactivity timer if started. */
 925         timer_active = del_timer_sync(&cfhsi->timer);
 926
 927         spin_unlock_bh(&cfhsi->lock);
 928
 929         if (timer_active) {
 930                 struct cfhsi_desc *desc = (struct cfhsi_desc *)cfhsi->tx_buf;
 931                 int len;
 932                 int res;
 933
 934                 /* Create HSI frame. */
 935                 len = cfhsi_tx_frm(desc, cfhsi);
 936                 WARN_ON(!len);
 937
 938                 /* Set up new transfer. */
 939                 res = cfhsi->dev->cfhsi_tx(cfhsi->tx_buf, len, cfhsi->dev);
 940                 if (WARN_ON(res < 0)) {
 941                         dev_err(&cfhsi->ndev->dev, "%s: TX error %d.\n",
 942                                 __func__, res);
 943                         cfhsi_abort_tx(cfhsi);
 944                 }
 945         } else {
 946                 /* Schedule wake up work queue if the we initiate. */
 947                 if (!test_and_set_bit(CFHSI_WAKE_UP, &cfhsi->bits))
 948                         queue_work(cfhsi->wq, &cfhsi->wake_up_work);
 949         }
 950
 951         return 0;
 952 }
 953
 954 static int cfhsi_open(struct net_device *dev)
 955 {
 956         netif_wake_queue(dev);
 957
 958         return 0;
 959 }
 960
 961 static int cfhsi_close(struct net_device *dev)
 962 {
 963         netif_stop_queue(dev);
 964
 965         return 0;
 966 }
 967
 968 static const struct net_device_ops cfhsi_ops = {
 969         .ndo_open = cfhsi_open,
 970         .ndo_stop = cfhsi_close,
 971         .ndo_start_xmit = cfhsi_xmit
 972 };
 973
 974 static void cfhsi_setup(struct net_device *dev)
 975 {
 976         struct cfhsi *cfhsi = netdev_priv(dev);
 977         dev->features = 0;
 978         dev->netdev_ops = &cfhsi_ops;
 979         dev->type = ARPHRD_CAIF;
 980         dev->flags = IFF_POINTOPOINT | IFF_NOARP;
 981         dev->mtu = CFHSI_MAX_CAIF_FRAME_SZ;
 982         dev->tx_queue_len = 0;
 983         dev->destructor = free_netdev;
 984         skb_queue_head_init(&cfhsi->qhead);
 985         cfhsi->cfdev.link_select = CAIF_LINK_HIGH_BANDW;
 986         cfhsi->cfdev.use_frag = false;
 987         cfhsi->cfdev.use_stx = false;
 988         cfhsi->cfdev.use_fcs = false;
 989         cfhsi->ndev = dev;
 990 }
 991
 992 int cfhsi_probe(struct platform_device *pdev)
 993 {
 994         struct cfhsi *cfhsi = NULL;
 995         struct net_device *ndev;
 996         struct cfhsi_dev *dev;
 997         int res;
 998
 999         ndev = alloc_netdev(sizeof(struct cfhsi), "cfhsi%d", cfhsi_setup);
1000         if (!ndev)
1001                 return -ENODEV;
1002
1003         cfhsi = netdev_priv(ndev);
1004         cfhsi->ndev = ndev;
1005         cfhsi->pdev = pdev;
1006
1007         /* Initialize state vaiables. */
1008         cfhsi->tx_state = CFHSI_TX_STATE_IDLE;
1009         cfhsi->rx_state.state = CFHSI_RX_STATE_DESC;
1010
1011         /* Set flow info */
1012         cfhsi->flow_off_sent = 0;
1013         cfhsi->q_low_mark = LOW_WATER_MARK;
1014         cfhsi->q_high_mark = HIGH_WATER_MARK;
1015
1016         /* Assign the HSI device. */
1017         dev = (struct cfhsi_dev *)pdev->dev.platform_data;
1018         cfhsi->dev = dev;
1019
1020         /* Assign the driver to this HSI device. */
1021         dev->drv = &cfhsi->drv;
1022
1023         /*
1024          * Allocate a TX buffer with the size of a HSI packet descriptors
1025          * and the necessary room for CAIF payload frames.
1026          */
1027         cfhsi->tx_buf = kzalloc(CFHSI_BUF_SZ_TX, GFP_KERNEL);
1028         if (!cfhsi->tx_buf) {
1029                 res = -ENODEV;
1030                 goto err_alloc_tx;
1031         }
1032
1033         /*
1034          * Allocate a RX buffer with the size of two HSI packet descriptors and
1035          * the necessary room for CAIF payload frames.
1036          */
1037         cfhsi->rx_buf = kzalloc(CFHSI_BUF_SZ_RX, GFP_KERNEL);
1038         if (!cfhsi->rx_buf) {
1039                 res = -ENODEV;
1040                 goto err_alloc_rx;
1041         }
1042
1043         /* Pre-calculate inactivity timeout. */
1044         if (inactivity_timeout != -1) {
1045                 cfhsi->inactivity_timeout =
1046                                 inactivity_timeout * HZ / 1000;
1047                 if (!cfhsi->inactivity_timeout)
1048                         cfhsi->inactivity_timeout = 1;
1049                 else if (cfhsi->inactivity_timeout > NEXT_TIMER_MAX_DELTA)
1050                         cfhsi->inactivity_timeout = NEXT_TIMER_MAX_DELTA;
1051         } else {
1052                 cfhsi->inactivity_timeout = NEXT_TIMER_MAX_DELTA;
1053         }
1054
1055         /* Initialize recieve vaiables. */
1056         cfhsi->rx_ptr = cfhsi->rx_buf;
1057         cfhsi->rx_len = CFHSI_DESC_SZ;
1058
1059         /* Initialize spin locks. */
1060         spin_lock_init(&cfhsi->lock);
1061
1062         /* Set up the driver. */
1063         cfhsi->drv.tx_done_cb = cfhsi_tx_done_cb;
1064         cfhsi->drv.rx_done_cb = cfhsi_rx_done_cb;
1065         cfhsi->drv.wake_up_cb = cfhsi_wake_up_cb;
1066         cfhsi->drv.wake_down_cb = cfhsi_wake_down_cb;
1067
1068         /* Initialize the work queues. */
1069         INIT_WORK(&cfhsi->wake_up_work, cfhsi_wake_up);
1070         INIT_WORK(&cfhsi->wake_down_work, cfhsi_wake_down);
1071         INIT_WORK(&cfhsi->out_of_sync_work, cfhsi_out_of_sync);
1072
1073         /* Clear all bit fields. */
1074         clear_bit(CFHSI_WAKE_UP_ACK, &cfhsi->bits);
1075         clear_bit(CFHSI_WAKE_DOWN_ACK, &cfhsi->bits);
1076         clear_bit(CFHSI_WAKE_UP, &cfhsi->bits);
1077         clear_bit(CFHSI_AWAKE, &cfhsi->bits);
1078
1079         /* Create work thread. */
1080         cfhsi->wq = create_singlethread_workqueue(pdev->name);
1081         if (!cfhsi->wq) {
1082                 dev_err(&ndev->dev, "%s: Failed to create work queue.\n",
1083                         __func__);
1084                 res = -ENODEV;
1085                 goto err_create_wq;
1086         }
1087
1088         /* Initialize wait queues. */
1089         init_waitqueue_head(&cfhsi->wake_up_wait);
1090         init_waitqueue_head(&cfhsi->wake_down_wait);
1091         init_waitqueue_head(&cfhsi->flush_fifo_wait);
1092
1093         /* Setup the inactivity timer. */
1094         init_timer(&cfhsi->timer);
1095         cfhsi->timer.data = (unsigned long)cfhsi;
1096         cfhsi->timer.function = cfhsi_inactivity_tout;
1097         /* Setup the slowpath RX timer. */
1098         init_timer(&cfhsi->rx_slowpath_timer);
1099         cfhsi->rx_slowpath_timer.data = (unsigned long)cfhsi;
1100         cfhsi->rx_slowpath_timer.function = cfhsi_rx_slowpath;
1101
1102         /* Add CAIF HSI device to list. */
1103         spin_lock(&cfhsi_list_lock);
1104         list_add_tail(&cfhsi->list, &cfhsi_list);
1105         spin_unlock(&cfhsi_list_lock);
1106
1107         /* Activate HSI interface. */
1108         res = cfhsi->dev->cfhsi_up(cfhsi->dev);
1109         if (res) {
1110                 dev_err(&cfhsi->ndev->dev,
1111                         "%s: can't activate HSI interface: %d.\n",
1112                         __func__, res);
1113                 goto err_activate;
1114         }
1115
1116         /* Flush FIFO */
1117         res = cfhsi_flush_fifo(cfhsi);
1118         if (res) {
1119                 dev_err(&ndev->dev, "%s: Can't flush FIFO: %d.\n",
1120                         __func__, res);
1121                 goto err_net_reg;
1122         }
1123
1124         /* Register network device. */
1125         res = register_netdev(ndev);
1126         if (res) {
1127                 dev_err(&ndev->dev, "%s: Registration error: %d.\n",
1128                         __func__, res);
1129                 goto err_net_reg;
1130         }
1131
1132         netif_stop_queue(ndev);
1133
1134         return res;
1135
1136  err_net_reg:
1137         cfhsi->dev->cfhsi_down(cfhsi->dev);
1138  err_activate:
1139         destroy_workqueue(cfhsi->wq);
1140  err_create_wq:
1141         kfree(cfhsi->rx_buf);
1142  err_alloc_rx:
1143         kfree(cfhsi->tx_buf);
1144  err_alloc_tx:
1145         free_netdev(ndev);
1146
1147         return res;
1148 }
1149
1150 static void cfhsi_shutdown(struct cfhsi *cfhsi)
1151 {
1152         u8 *tx_buf, *rx_buf;
1153
1154         /* Stop TXing */
1155         netif_tx_stop_all_queues(cfhsi->ndev);
1156
1157         /* going to shutdown driver */
1158         set_bit(CFHSI_SHUTDOWN, &cfhsi->bits);
1159
1160         /* Flush workqueue */
1161         flush_workqueue(cfhsi->wq);
1162
1163         /* Delete timers if pending */
1164         del_timer_sync(&cfhsi->timer);
1165         del_timer_sync(&cfhsi->rx_slowpath_timer);
1166
1167         /* Cancel pending RX request (if any) */
1168         cfhsi->dev->cfhsi_rx_cancel(cfhsi->dev);
1169
1170         /* Destroy workqueue */
1171         destroy_workqueue(cfhsi->wq);
1172
1173         /* Store bufferes: will be freed later. */
1174         tx_buf = cfhsi->tx_buf;
1175         rx_buf = cfhsi->rx_buf;
1176
1177         /* Flush transmit queues. */
1178         cfhsi_abort_tx(cfhsi);
1179
1180         /* Deactivate interface */
1181         cfhsi->dev->cfhsi_down(cfhsi->dev);
1182
1183         /* Finally unregister the network device. */
1184         unregister_netdev(cfhsi->ndev);
1185
1186         /* Free buffers. */
1187         kfree(tx_buf);
1188         kfree(rx_buf);
1189 }
1190
1191 int cfhsi_remove(struct platform_device *pdev)
1192 {
1193         struct list_head *list_node;
1194         struct list_head *n;
1195         struct cfhsi *cfhsi = NULL;
1196         struct cfhsi_dev *dev;
1197
1198         dev = (struct cfhsi_dev *)pdev->dev.platform_data;
1199         spin_lock(&cfhsi_list_lock);
1200         list_for_each_safe(list_node, n, &cfhsi_list) {
1201                 cfhsi = list_entry(list_node, struct cfhsi, list);
1202                 /* Find the corresponding device. */
1203                 if (cfhsi->dev == dev) {
1204                         /* Remove from list. */
1205                         list_del(list_node);
1206                         spin_unlock(&cfhsi_list_lock);
1207
1208                         /* Shutdown driver. */
1209                         cfhsi_shutdown(cfhsi);
1210
1211                         return 0;
1212                 }
1213         }
1214         spin_unlock(&cfhsi_list_lock);
1215         return -ENODEV;
1216 }
1217
1218 struct platform_driver cfhsi_plat_drv = {
1219         .probe = cfhsi_probe,
1220         .remove = cfhsi_remove,
1221         .driver = {
1222                    .name = "cfhsi",
1223                    .owner = THIS_MODULE,
1224                    },
1225 };
1226
1227 static void __exit cfhsi_exit_module(void)
1228 {
1229         struct list_head *list_node;
1230         struct list_head *n;
1231         struct cfhsi *cfhsi = NULL;
1232
1233         spin_lock(&cfhsi_list_lock);
1234         list_for_each_safe(list_node, n, &cfhsi_list) {
1235                 cfhsi = list_entry(list_node, struct cfhsi, list);
1236
1237                 /* Remove from list. */
1238                 list_del(list_node);
1239                 spin_unlock(&cfhsi_list_lock);
1240
1241                 /* Shutdown driver. */
1242                 cfhsi_shutdown(cfhsi);
1243
1244                 spin_lock(&cfhsi_list_lock);
1245         }
1246         spin_unlock(&cfhsi_list_lock);
1247
1248         /* Unregister platform driver. */
1249         platform_driver_unregister(&cfhsi_plat_drv);
1250 }
1251
1252 static int __init cfhsi_init_module(void)
1253 {
1254         int result;
1255
1256         /* Initialize spin lock. */
1257         spin_lock_init(&cfhsi_list_lock);
1258
1259         /* Register platform driver. */
1260         result = platform_driver_register(&cfhsi_plat_drv);
1261         if (result) {
1262                 printk(KERN_ERR "Could not register platform HSI driver: %d.\n",
1263                         result);
1264                 goto err_dev_register;
1265         }
1266
1267         return result;
1268
1269  err_dev_register:
1270         return result;
1271 }
1272
1273 module_init(cfhsi_init_module);
1274 module_exit(cfhsi_exit_module);