git.oblomov.eu Git - linux-2.6/blob - drivers/s390/scsi/zfcp_qdio.c

   1 /*
   2  * This file is part of the zfcp device driver for
   3  * FCP adapters for IBM System z9 and zSeries.
   4  *
   5  * (C) Copyright IBM Corp. 2002, 2006
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2, or (at your option)
  10  * any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  20  */
  21
  22 #include "zfcp_ext.h"
  23
  24 static void zfcp_qdio_sbal_limit(struct zfcp_fsf_req *, int);
  25 static inline volatile struct qdio_buffer_element *zfcp_qdio_sbale_get
  26         (struct zfcp_qdio_queue *, int, int);
  27 static inline volatile struct qdio_buffer_element *zfcp_qdio_sbale_resp
  28         (struct zfcp_fsf_req *, int, int);
  29 static volatile struct qdio_buffer_element *zfcp_qdio_sbal_chain
  30         (struct zfcp_fsf_req *, unsigned long);
  31 static volatile struct qdio_buffer_element *zfcp_qdio_sbale_next
  32         (struct zfcp_fsf_req *, unsigned long);
  33 static int zfcp_qdio_sbals_zero(struct zfcp_qdio_queue *, int, int);
  34 static inline int zfcp_qdio_sbals_wipe(struct zfcp_fsf_req *);
  35 static void zfcp_qdio_sbale_fill
  36         (struct zfcp_fsf_req *, unsigned long, void *, int);
  37 static int zfcp_qdio_sbals_from_segment
  38         (struct zfcp_fsf_req *, unsigned long, void *, unsigned long);
  39
  40 static qdio_handler_t zfcp_qdio_request_handler;
  41 static qdio_handler_t zfcp_qdio_response_handler;
  42 static int zfcp_qdio_handler_error_check(struct zfcp_adapter *,
  43         unsigned int, unsigned int, unsigned int, int, int);
  44
  45 #define ZFCP_LOG_AREA                   ZFCP_LOG_AREA_QDIO
  46
  47 /*
  48  * Frees BUFFER memory for each of the pointers of the struct qdio_buffer array
  49  * in the adapter struct sbuf is the pointer array.
  50  *
  51  * locks:       must only be called with zfcp_data.config_sema taken
  52  */
  53 static void
  54 zfcp_qdio_buffers_dequeue(struct qdio_buffer **sbuf)
  55 {
  56         int pos;
  57
  58         for (pos = 0; pos < QDIO_MAX_BUFFERS_PER_Q; pos += QBUFF_PER_PAGE)
  59                 free_page((unsigned long) sbuf[pos]);
  60 }
  61
  62 /*
  63  * Allocates BUFFER memory to each of the pointers of the qdio_buffer_t
  64  * array in the adapter struct.
  65  * Cur_buf is the pointer array
  66  *
  67  * returns:     zero on success else -ENOMEM
  68  * locks:       must only be called with zfcp_data.config_sema taken
  69  */
  70 static int
  71 zfcp_qdio_buffers_enqueue(struct qdio_buffer **sbuf)
  72 {
  73         int pos;
  74
  75         for (pos = 0; pos < QDIO_MAX_BUFFERS_PER_Q; pos += QBUFF_PER_PAGE) {
  76                 sbuf[pos] = (struct qdio_buffer *) get_zeroed_page(GFP_KERNEL);
  77                 if (!sbuf[pos]) {
  78                         zfcp_qdio_buffers_dequeue(sbuf);
  79                         return -ENOMEM;
  80                 }
  81         }
  82         for (pos = 0; pos < QDIO_MAX_BUFFERS_PER_Q; pos++)
  83                 if (pos % QBUFF_PER_PAGE)
  84                         sbuf[pos] = sbuf[pos - 1] + 1;
  85         return 0;
  86 }
  87
  88 /* locks:       must only be called with zfcp_data.config_sema taken */
  89 int
  90 zfcp_qdio_allocate_queues(struct zfcp_adapter *adapter)
  91 {
  92         int ret;
  93
  94         ret = zfcp_qdio_buffers_enqueue(adapter->request_queue.buffer);
  95         if (ret)
  96                 return ret;
  97         return zfcp_qdio_buffers_enqueue(adapter->response_queue.buffer);
  98 }
  99
 100 /* locks:       must only be called with zfcp_data.config_sema taken */
 101 void
 102 zfcp_qdio_free_queues(struct zfcp_adapter *adapter)
 103 {
 104         ZFCP_LOG_TRACE("freeing request_queue buffers\n");
 105         zfcp_qdio_buffers_dequeue(adapter->request_queue.buffer);
 106
 107         ZFCP_LOG_TRACE("freeing response_queue buffers\n");
 108         zfcp_qdio_buffers_dequeue(adapter->response_queue.buffer);
 109 }
 110
 111 int
 112 zfcp_qdio_allocate(struct zfcp_adapter *adapter)
 113 {
 114         struct qdio_initialize *init_data;
 115
 116         init_data = &adapter->qdio_init_data;
 117
 118         init_data->cdev = adapter->ccw_device;
 119         init_data->q_format = QDIO_SCSI_QFMT;
 120         memcpy(init_data->adapter_name, zfcp_get_busid_by_adapter(adapter), 8);
 121         ASCEBC(init_data->adapter_name, 8);
 122         init_data->qib_param_field_format = 0;
 123         init_data->qib_param_field = NULL;
 124         init_data->input_slib_elements = NULL;
 125         init_data->output_slib_elements = NULL;
 126         init_data->min_input_threshold = ZFCP_MIN_INPUT_THRESHOLD;
 127         init_data->max_input_threshold = ZFCP_MAX_INPUT_THRESHOLD;
 128         init_data->min_output_threshold = ZFCP_MIN_OUTPUT_THRESHOLD;
 129         init_data->max_output_threshold = ZFCP_MAX_OUTPUT_THRESHOLD;
 130         init_data->no_input_qs = 1;
 131         init_data->no_output_qs = 1;
 132         init_data->input_handler = zfcp_qdio_response_handler;
 133         init_data->output_handler = zfcp_qdio_request_handler;
 134         init_data->int_parm = (unsigned long) adapter;
 135         init_data->flags = QDIO_INBOUND_0COPY_SBALS |
 136             QDIO_OUTBOUND_0COPY_SBALS | QDIO_USE_OUTBOUND_PCIS;
 137         init_data->input_sbal_addr_array =
 138             (void **) (adapter->response_queue.buffer);
 139         init_data->output_sbal_addr_array =
 140             (void **) (adapter->request_queue.buffer);
 141
 142         return qdio_allocate(init_data);
 143 }
 144
 145 /*
 146  * function:    zfcp_qdio_handler_error_check
 147  *
 148  * purpose:     called by the response handler to determine error condition
 149  *
 150  * returns:     error flag
 151  *
 152  */
 153 static int
 154 zfcp_qdio_handler_error_check(struct zfcp_adapter *adapter, unsigned int status,
 155                               unsigned int qdio_error, unsigned int siga_error,
 156                               int first_element, int elements_processed)
 157 {
 158         int retval = 0;
 159
 160         if (unlikely(status & QDIO_STATUS_LOOK_FOR_ERROR)) {
 161                 retval = -EIO;
 162
 163                 ZFCP_LOG_INFO("QDIO problem occurred (status=0x%x, "
 164                               "qdio_error=0x%x, siga_error=0x%x)\n",
 165                               status, qdio_error, siga_error);
 166
 167                 zfcp_hba_dbf_event_qdio(adapter, status, qdio_error, siga_error,
 168                                 first_element, elements_processed);
 169                /*
 170                 * Restarting IO on the failed adapter from scratch.
 171                 * Since we have been using this adapter, it is save to assume
 172                 * that it is not failed but recoverable. The card seems to
 173                 * report link-up events by self-initiated queue shutdown.
 174                 * That is why we need to clear the link-down flag
 175                 * which is set again in case we have missed by a mile.
 176                 */
 177                 zfcp_erp_adapter_reopen(adapter,
 178                                        ZFCP_STATUS_ADAPTER_LINK_UNPLUGGED |
 179                                        ZFCP_STATUS_COMMON_ERP_FAILED);
 180         }
 181         return retval;
 182 }
 183
 184 /*
 185  * function:    zfcp_qdio_request_handler
 186  *
 187  * purpose:     is called by QDIO layer for completed SBALs in request queue
 188  *
 189  * returns:     (void)
 190  */
 191 static void
 192 zfcp_qdio_request_handler(struct ccw_device *ccw_device,
 193                           unsigned int status,
 194                           unsigned int qdio_error,
 195                           unsigned int siga_error,
 196                           unsigned int queue_number,
 197                           int first_element,
 198                           int elements_processed,
 199                           unsigned long int_parm)
 200 {
 201         struct zfcp_adapter *adapter;
 202         struct zfcp_qdio_queue *queue;
 203
 204         adapter = (struct zfcp_adapter *) int_parm;
 205         queue = &adapter->request_queue;
 206
 207         ZFCP_LOG_DEBUG("adapter %s, first=%d, elements_processed=%d\n",
 208                        zfcp_get_busid_by_adapter(adapter),
 209                        first_element, elements_processed);
 210
 211         if (unlikely(zfcp_qdio_handler_error_check(adapter, status, qdio_error,
 212                                                    siga_error, first_element,
 213                                                    elements_processed)))
 214                 goto out;
 215         /*
 216          * we stored address of struct zfcp_adapter  data structure
 217          * associated with irq in int_parm
 218          */
 219
 220         /* cleanup all SBALs being program-owned now */
 221         zfcp_qdio_zero_sbals(queue->buffer, first_element, elements_processed);
 222
 223         /* increase free space in outbound queue */
 224         atomic_add(elements_processed, &queue->free_count);
 225         ZFCP_LOG_DEBUG("free_count=%d\n", atomic_read(&queue->free_count));
 226         wake_up(&adapter->request_wq);
 227         ZFCP_LOG_DEBUG("elements_processed=%d, free count=%d\n",
 228                        elements_processed, atomic_read(&queue->free_count));
 229  out:
 230         return;
 231 }
 232
 233 /**
 234  * zfcp_qdio_reqid_check - checks for valid reqids.
 235  */
 236 static void zfcp_qdio_reqid_check(struct zfcp_adapter *adapter,
 237                                   unsigned long req_id)
 238 {
 239         struct zfcp_fsf_req *fsf_req;
 240         unsigned long flags;
 241
 242         debug_long_event(adapter->erp_dbf, 4, req_id);
 243
 244         spin_lock_irqsave(&adapter->req_list_lock, flags);
 245         fsf_req = zfcp_reqlist_find(adapter, req_id);
 246
 247         if (!fsf_req)
 248                 /*
 249                  * Unknown request means that we have potentially memory
 250                  * corruption and must stop the machine immediatly.
 251                  */
 252                 panic("error: unknown request id (%ld) on adapter %s.\n",
 253                       req_id, zfcp_get_busid_by_adapter(adapter));
 254
 255         zfcp_reqlist_remove(adapter, fsf_req);
 256         atomic_dec(&adapter->reqs_active);
 257         spin_unlock_irqrestore(&adapter->req_list_lock, flags);
 258
 259         /* finish the FSF request */
 260         zfcp_fsf_req_complete(fsf_req);
 261 }
 262
 263 /*
 264  * function:    zfcp_qdio_response_handler
 265  *
 266  * purpose:     is called by QDIO layer for completed SBALs in response queue
 267  *
 268  * returns:     (void)
 269  */
 270 static void
 271 zfcp_qdio_response_handler(struct ccw_device *ccw_device,
 272                            unsigned int status,
 273                            unsigned int qdio_error,
 274                            unsigned int siga_error,
 275                            unsigned int queue_number,
 276                            int first_element,
 277                            int elements_processed,
 278                            unsigned long int_parm)
 279 {
 280         struct zfcp_adapter *adapter;
 281         struct zfcp_qdio_queue *queue;
 282         int buffer_index;
 283         int i;
 284         struct qdio_buffer *buffer;
 285         int retval = 0;
 286         u8 count;
 287         u8 start;
 288         volatile struct qdio_buffer_element *buffere = NULL;
 289         int buffere_index;
 290
 291         adapter = (struct zfcp_adapter *) int_parm;
 292         queue = &adapter->response_queue;
 293
 294         if (unlikely(zfcp_qdio_handler_error_check(adapter, status, qdio_error,
 295                                                    siga_error, first_element,
 296                                                    elements_processed)))
 297                 goto out;
 298
 299         /*
 300          * we stored address of struct zfcp_adapter  data structure
 301          * associated with irq in int_parm
 302          */
 303
 304         buffere = &(queue->buffer[first_element]->element[0]);
 305         ZFCP_LOG_DEBUG("first BUFFERE flags=0x%x\n", buffere->flags);
 306         /*
 307          * go through all SBALs from input queue currently
 308          * returned by QDIO layer
 309          */
 310
 311         for (i = 0; i < elements_processed; i++) {
 312
 313                 buffer_index = first_element + i;
 314                 buffer_index %= QDIO_MAX_BUFFERS_PER_Q;
 315                 buffer = queue->buffer[buffer_index];
 316
 317                 /* go through all SBALEs of SBAL */
 318                 for (buffere_index = 0;
 319                      buffere_index < QDIO_MAX_ELEMENTS_PER_BUFFER;
 320                      buffere_index++) {
 321
 322                         /* look for QDIO request identifiers in SB */
 323                         buffere = &buffer->element[buffere_index];
 324                         zfcp_qdio_reqid_check(adapter,
 325                                               (unsigned long) buffere->addr);
 326
 327                         /*
 328                          * A single used SBALE per inbound SBALE has been
 329                          * implemented by QDIO so far. Hope they will
 330                          * do some optimisation. Will need to change to
 331                          * unlikely() then.
 332                          */
 333                         if (likely(buffere->flags & SBAL_FLAGS_LAST_ENTRY))
 334                                 break;
 335                 };
 336
 337                 if (unlikely(!(buffere->flags & SBAL_FLAGS_LAST_ENTRY))) {
 338                         ZFCP_LOG_NORMAL("bug: End of inbound data "
 339                                         "not marked!\n");
 340                 }
 341         }
 342
 343         /*
 344          * put range of SBALs back to response queue
 345          * (including SBALs which have already been free before)
 346          */
 347         count = atomic_read(&queue->free_count) + elements_processed;
 348         start = queue->free_index;
 349
 350         ZFCP_LOG_TRACE("calling do_QDIO on adapter %s (flags=0x%x, "
 351                        "queue_no=%i, index_in_queue=%i, count=%i, "
 352                        "buffers=0x%lx\n",
 353                        zfcp_get_busid_by_adapter(adapter),
 354                        QDIO_FLAG_SYNC_INPUT | QDIO_FLAG_UNDER_INTERRUPT,
 355                        0, start, count, (unsigned long) &queue->buffer[start]);
 356
 357         retval = do_QDIO(ccw_device,
 358                          QDIO_FLAG_SYNC_INPUT | QDIO_FLAG_UNDER_INTERRUPT,
 359                          0, start, count, NULL);
 360
 361         if (unlikely(retval)) {
 362                 atomic_set(&queue->free_count, count);
 363                 ZFCP_LOG_DEBUG("clearing of inbound data regions failed, "
 364                                "queues may be down "
 365                                "(count=%d, start=%d, retval=%d)\n",
 366                                count, start, retval);
 367         } else {
 368                 queue->free_index += count;
 369                 queue->free_index %= QDIO_MAX_BUFFERS_PER_Q;
 370                 atomic_set(&queue->free_count, 0);
 371                 ZFCP_LOG_TRACE("%i buffers enqueued to response "
 372                                "queue at position %i\n", count, start);
 373         }
 374  out:
 375         return;
 376 }
 377
 378 /**
 379  * zfcp_qdio_sbale_get - return pointer to SBALE of qdio_queue
 380  * @queue: queue from which SBALE should be returned
 381  * @sbal: specifies number of SBAL in queue
 382  * @sbale: specifes number of SBALE in SBAL
 383  */
 384 static inline volatile struct qdio_buffer_element *
 385 zfcp_qdio_sbale_get(struct zfcp_qdio_queue *queue, int sbal, int sbale)
 386 {
 387         return &queue->buffer[sbal]->element[sbale];
 388 }
 389
 390 /**
 391  * zfcp_qdio_sbale_req - return pointer to SBALE of request_queue for
 392  *      a struct zfcp_fsf_req
 393  */
 394 volatile struct qdio_buffer_element *
 395 zfcp_qdio_sbale_req(struct zfcp_fsf_req *fsf_req, int sbal, int sbale)
 396 {
 397         return zfcp_qdio_sbale_get(&fsf_req->adapter->request_queue,
 398                                    sbal, sbale);
 399 }
 400
 401 /**
 402  * zfcp_qdio_sbale_resp - return pointer to SBALE of response_queue for
 403  *      a struct zfcp_fsf_req
 404  */
 405 static inline volatile struct qdio_buffer_element *
 406 zfcp_qdio_sbale_resp(struct zfcp_fsf_req *fsf_req, int sbal, int sbale)
 407 {
 408         return zfcp_qdio_sbale_get(&fsf_req->adapter->response_queue,
 409                                    sbal, sbale);
 410 }
 411
 412 /**
 413  * zfcp_qdio_sbale_curr - return current SBALE on request_queue for
 414  *      a struct zfcp_fsf_req
 415  */
 416 volatile struct qdio_buffer_element *
 417 zfcp_qdio_sbale_curr(struct zfcp_fsf_req *fsf_req)
 418 {
 419         return zfcp_qdio_sbale_req(fsf_req, fsf_req->sbal_curr,
 420                                    fsf_req->sbale_curr);
 421 }
 422
 423 /**
 424  * zfcp_qdio_sbal_limit - determine maximum number of SBALs that can be used
 425  *      on the request_queue for a struct zfcp_fsf_req
 426  * @fsf_req: the number of the last SBAL that can be used is stored herein
 427  * @max_sbals: used to pass an upper limit for the number of SBALs
 428  *
 429  * Note: We can assume at least one free SBAL in the request_queue when called.
 430  */
 431 static void
 432 zfcp_qdio_sbal_limit(struct zfcp_fsf_req *fsf_req, int max_sbals)
 433 {
 434         int count = atomic_read(&fsf_req->adapter->request_queue.free_count);
 435         count = min(count, max_sbals);
 436         fsf_req->sbal_last  = fsf_req->sbal_first;
 437         fsf_req->sbal_last += (count - 1);
 438         fsf_req->sbal_last %= QDIO_MAX_BUFFERS_PER_Q;
 439 }
 440
 441 /**
 442  * zfcp_qdio_sbal_chain - chain SBALs if more than one SBAL is needed for a
 443  *      request
 444  * @fsf_req: zfcp_fsf_req to be processed
 445  * @sbtype: SBAL flags which have to be set in first SBALE of new SBAL
 446  *
 447  * This function changes sbal_curr, sbale_curr, sbal_number of fsf_req.
 448  */
 449 static volatile struct qdio_buffer_element *
 450 zfcp_qdio_sbal_chain(struct zfcp_fsf_req *fsf_req, unsigned long sbtype)
 451 {
 452         volatile struct qdio_buffer_element *sbale;
 453
 454         /* set last entry flag in current SBALE of current SBAL */
 455         sbale = zfcp_qdio_sbale_curr(fsf_req);
 456         sbale->flags |= SBAL_FLAGS_LAST_ENTRY;
 457
 458         /* don't exceed last allowed SBAL */
 459         if (fsf_req->sbal_curr == fsf_req->sbal_last)
 460                 return NULL;
 461
 462         /* set chaining flag in first SBALE of current SBAL */
 463         sbale = zfcp_qdio_sbale_req(fsf_req, fsf_req->sbal_curr, 0);
 464         sbale->flags |= SBAL_FLAGS0_MORE_SBALS;
 465
 466         /* calculate index of next SBAL */
 467         fsf_req->sbal_curr++;
 468         fsf_req->sbal_curr %= QDIO_MAX_BUFFERS_PER_Q;
 469
 470         /* keep this requests number of SBALs up-to-date */
 471         fsf_req->sbal_number++;
 472
 473         /* start at first SBALE of new SBAL */
 474         fsf_req->sbale_curr = 0;
 475
 476         /* set storage-block type for new SBAL */
 477         sbale = zfcp_qdio_sbale_curr(fsf_req);
 478         sbale->flags |= sbtype;
 479
 480         return sbale;
 481 }
 482
 483 /**
 484  * zfcp_qdio_sbale_next - switch to next SBALE, chain SBALs if needed
 485  */
 486 static volatile struct qdio_buffer_element *
 487 zfcp_qdio_sbale_next(struct zfcp_fsf_req *fsf_req, unsigned long sbtype)
 488 {
 489         if (fsf_req->sbale_curr == ZFCP_LAST_SBALE_PER_SBAL)
 490                 return zfcp_qdio_sbal_chain(fsf_req, sbtype);
 491
 492         fsf_req->sbale_curr++;
 493
 494         return zfcp_qdio_sbale_curr(fsf_req);
 495 }
 496
 497 /**
 498  * zfcp_qdio_sbals_zero - initialize SBALs between first and last in queue
 499  *      with zero from
 500  */
 501 static int
 502 zfcp_qdio_sbals_zero(struct zfcp_qdio_queue *queue, int first, int last)
 503 {
 504         struct qdio_buffer **buf = queue->buffer;
 505         int curr = first;
 506         int count = 0;
 507
 508         for(;;) {
 509                 curr %= QDIO_MAX_BUFFERS_PER_Q;
 510                 count++;
 511                 memset(buf[curr], 0, sizeof(struct qdio_buffer));
 512                 if (curr == last)
 513                         break;
 514                 curr++;
 515         }
 516         return count;
 517 }
 518
 519
 520 /**
 521  * zfcp_qdio_sbals_wipe - reset all changes in SBALs for an fsf_req
 522  */
 523 static inline int
 524 zfcp_qdio_sbals_wipe(struct zfcp_fsf_req *fsf_req)
 525 {
 526         return zfcp_qdio_sbals_zero(&fsf_req->adapter->request_queue,
 527                                     fsf_req->sbal_first, fsf_req->sbal_curr);
 528 }
 529
 530
 531 /**
 532  * zfcp_qdio_sbale_fill - set address and length in current SBALE
 533  *      on request_queue
 534  */
 535 static void
 536 zfcp_qdio_sbale_fill(struct zfcp_fsf_req *fsf_req, unsigned long sbtype,
 537                      void *addr, int length)
 538 {
 539         volatile struct qdio_buffer_element *sbale;
 540
 541         sbale = zfcp_qdio_sbale_curr(fsf_req);
 542         sbale->addr = addr;
 543         sbale->length = length;
 544 }
 545
 546 /**
 547  * zfcp_qdio_sbals_from_segment - map memory segment to SBALE(s)
 548  * @fsf_req: request to be processed
 549  * @sbtype: SBALE flags
 550  * @start_addr: address of memory segment
 551  * @total_length: length of memory segment
 552  *
 553  * Alignment and length of the segment determine how many SBALEs are needed
 554  * for the memory segment.
 555  */
 556 static int
 557 zfcp_qdio_sbals_from_segment(struct zfcp_fsf_req *fsf_req, unsigned long sbtype,
 558                              void *start_addr, unsigned long total_length)
 559 {
 560         unsigned long remaining, length;
 561         void *addr;
 562
 563         /* split segment up heeding page boundaries */
 564         for (addr = start_addr, remaining = total_length; remaining > 0;
 565              addr += length, remaining -= length) {
 566                 /* get next free SBALE for new piece */
 567                 if (NULL == zfcp_qdio_sbale_next(fsf_req, sbtype)) {
 568                         /* no SBALE left, clean up and leave */
 569                         zfcp_qdio_sbals_wipe(fsf_req);
 570                         return -EINVAL;
 571                 }
 572                 /* calculate length of new piece */
 573                 length = min(remaining,
 574                              (PAGE_SIZE - ((unsigned long) addr &
 575                                            (PAGE_SIZE - 1))));
 576                 /* fill current SBALE with calculated piece */
 577                 zfcp_qdio_sbale_fill(fsf_req, sbtype, addr, length);
 578         }
 579         return total_length;
 580 }
 581
 582
 583 /**
 584  * zfcp_qdio_sbals_from_sg - fill SBALs from scatter-gather list
 585  * @fsf_req: request to be processed
 586  * @sbtype: SBALE flags
 587  * @sg: scatter-gather list
 588  * @sg_count: number of elements in scatter-gather list
 589  * @max_sbals: upper bound for number of SBALs to be used
 590  */
 591 int
 592 zfcp_qdio_sbals_from_sg(struct zfcp_fsf_req *fsf_req, unsigned long sbtype,
 593                         struct scatterlist *sgl, int sg_count, int max_sbals)
 594 {
 595         int sg_index;
 596         struct scatterlist *sg_segment;
 597         int retval;
 598         volatile struct qdio_buffer_element *sbale;
 599         int bytes = 0;
 600
 601         /* figure out last allowed SBAL */
 602         zfcp_qdio_sbal_limit(fsf_req, max_sbals);
 603
 604         /* set storage-block type for current SBAL */
 605         sbale = zfcp_qdio_sbale_req(fsf_req, fsf_req->sbal_curr, 0);
 606         sbale->flags |= sbtype;
 607
 608         /* process all segements of scatter-gather list */
 609         for_each_sg(sgl, sg_segment, sg_count, sg_index) {
 610                 retval = zfcp_qdio_sbals_from_segment(
 611                                 fsf_req,
 612                                 sbtype,
 613                                 zfcp_sg_to_address(sg_segment),
 614                                 sg_segment->length);
 615                 if (retval < 0) {
 616                         bytes = retval;
 617                         goto out;
 618                 } else
 619                         bytes += retval;
 620         }
 621         /* assume that no other SBALEs are to follow in the same SBAL */
 622         sbale = zfcp_qdio_sbale_curr(fsf_req);
 623         sbale->flags |= SBAL_FLAGS_LAST_ENTRY;
 624 out:
 625         return bytes;
 626 }
 627
 628
 629 /**
 630  * zfcp_qdio_sbals_from_scsicmnd - fill SBALs from scsi command
 631  * @fsf_req: request to be processed
 632  * @sbtype: SBALE flags
 633  * @scsi_cmnd: either scatter-gather list or buffer contained herein is used
 634  *      to fill SBALs
 635  */
 636 int
 637 zfcp_qdio_sbals_from_scsicmnd(struct zfcp_fsf_req *fsf_req,
 638                               unsigned long sbtype, struct scsi_cmnd *scsi_cmnd)
 639 {
 640         return zfcp_qdio_sbals_from_sg(fsf_req, sbtype, scsi_sglist(scsi_cmnd),
 641                                        scsi_sg_count(scsi_cmnd),
 642                                        ZFCP_MAX_SBALS_PER_REQ);
 643 }
 644
 645 /**
 646  * zfcp_qdio_determine_pci - set PCI flag in first SBALE on qdio queue if needed
 647  */
 648 int
 649 zfcp_qdio_determine_pci(struct zfcp_qdio_queue *req_queue,
 650                         struct zfcp_fsf_req *fsf_req)
 651 {
 652         int new_distance_from_int;
 653         int pci_pos;
 654         volatile struct qdio_buffer_element *sbale;
 655
 656         new_distance_from_int = req_queue->distance_from_int +
 657                 fsf_req->sbal_number;
 658
 659         if (unlikely(new_distance_from_int >= ZFCP_QDIO_PCI_INTERVAL)) {
 660                 new_distance_from_int %= ZFCP_QDIO_PCI_INTERVAL;
 661                 pci_pos  = fsf_req->sbal_first;
 662                 pci_pos += fsf_req->sbal_number;
 663                 pci_pos -= new_distance_from_int;
 664                 pci_pos -= 1;
 665                 pci_pos %= QDIO_MAX_BUFFERS_PER_Q;
 666                 sbale = zfcp_qdio_sbale_req(fsf_req, pci_pos, 0);
 667                 sbale->flags |= SBAL_FLAGS0_PCI;
 668         }
 669         return new_distance_from_int;
 670 }
 671
 672 /*
 673  * function:    zfcp_zero_sbals
 674  *
 675  * purpose:     zeros specified range of SBALs
 676  *
 677  * returns:
 678  */
 679 void
 680 zfcp_qdio_zero_sbals(struct qdio_buffer *buf[], int first, int clean_count)
 681 {
 682         int cur_pos;
 683         int index;
 684
 685         for (cur_pos = first; cur_pos < (first + clean_count); cur_pos++) {
 686                 index = cur_pos % QDIO_MAX_BUFFERS_PER_Q;
 687                 memset(buf[index], 0, sizeof (struct qdio_buffer));
 688                 ZFCP_LOG_TRACE("zeroing BUFFER %d at address %p\n",
 689                                index, buf[index]);
 690         }
 691 }
 692
 693 #undef ZFCP_LOG_AREA