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   1 /*
   2  * linux/drivers/s390/scsi/zfcp_qdio.c
   3  *
   4  * FCP adapter driver for IBM eServer zSeries
   5  *
   6  * QDIO related routines
   7  *
   8  * (C) Copyright IBM Corp. 2002, 2004
   9  *
  10  * Authors:
  11  *      Martin Peschke <mpeschke@de.ibm.com>
  12  *      Raimund Schroeder <raimund.schroeder@de.ibm.com>
  13  *      Wolfgang Taphorn
  14  *      Heiko Carstens <heiko.carstens@de.ibm.com>
  15  *      Andreas Herrmann <aherrman@de.ibm.com>
  16  *
  17  * This program is free software; you can redistribute it and/or modify
  18  * it under the terms of the GNU General Public License as published by
  19  * the Free Software Foundation; either version 2, or (at your option)
  20  * any later version.
  21  *
  22  * This program is distributed in the hope that it will be useful,
  23  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  24  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  25  * GNU General Public License for more details.
  26  *
  27  * You should have received a copy of the GNU General Public License
  28  * along with this program; if not, write to the Free Software
  29  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  30  */
  31
  32 #define ZFCP_QDIO_C_REVISION "$Revision: 1.20 $"
  33
  34 #include "zfcp_ext.h"
  35
  36 static inline void zfcp_qdio_sbal_limit(struct zfcp_fsf_req *, int);
  37 static inline volatile struct qdio_buffer_element *zfcp_qdio_sbale_get
  38         (struct zfcp_qdio_queue *, int, int);
  39 static inline volatile struct qdio_buffer_element *zfcp_qdio_sbale_resp
  40         (struct zfcp_fsf_req *, int, int);
  41 static inline volatile struct qdio_buffer_element *zfcp_qdio_sbal_chain
  42         (struct zfcp_fsf_req *, unsigned long);
  43 static inline volatile struct qdio_buffer_element *zfcp_qdio_sbale_next
  44         (struct zfcp_fsf_req *, unsigned long);
  45 static inline int zfcp_qdio_sbals_zero(struct zfcp_qdio_queue *, int, int);
  46 static inline int zfcp_qdio_sbals_wipe(struct zfcp_fsf_req *);
  47 static inline void zfcp_qdio_sbale_fill
  48         (struct zfcp_fsf_req *, unsigned long, void *, int);
  49 static inline int zfcp_qdio_sbals_from_segment
  50         (struct zfcp_fsf_req *, unsigned long, void *, unsigned long);
  51 static inline int zfcp_qdio_sbals_from_buffer
  52         (struct zfcp_fsf_req *, unsigned long, void *, unsigned long, int);
  53
  54 static qdio_handler_t zfcp_qdio_request_handler;
  55 static qdio_handler_t zfcp_qdio_response_handler;
  56 static int zfcp_qdio_handler_error_check(struct zfcp_adapter *,
  57                                          unsigned int,
  58                                          unsigned int, unsigned int);
  59
  60 #define ZFCP_LOG_AREA                   ZFCP_LOG_AREA_QDIO
  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 and count can be any number of required
  66  * buffers, the page-fitting arithmetic is done entirely within this funciton.
  67  *
  68  * returns:     number of buffers allocated
  69  * locks:       must only be called with zfcp_data.config_sema taken
  70  */
  71 static int
  72 zfcp_qdio_buffers_enqueue(struct qdio_buffer **cur_buf, int count)
  73 {
  74         int buf_pos;
  75         int qdio_buffers_per_page;
  76         int page_pos = 0;
  77         struct qdio_buffer *first_in_page = NULL;
  78
  79         qdio_buffers_per_page = PAGE_SIZE / sizeof (struct qdio_buffer);
  80         ZFCP_LOG_TRACE("buffers_per_page=%d\n", qdio_buffers_per_page);
  81
  82         for (buf_pos = 0; buf_pos < count; buf_pos++) {
  83                 if (page_pos == 0) {
  84                         cur_buf[buf_pos] = (struct qdio_buffer *)
  85                             get_zeroed_page(GFP_KERNEL);
  86                         if (cur_buf[buf_pos] == NULL) {
  87                                 ZFCP_LOG_INFO("error: allocation of "
  88                                               "QDIO buffer failed \n");
  89                                 goto out;
  90                         }
  91                         first_in_page = cur_buf[buf_pos];
  92                 } else {
  93                         cur_buf[buf_pos] = first_in_page + page_pos;
  94
  95                 }
  96                 /* was initialised to zero */
  97                 page_pos++;
  98                 page_pos %= qdio_buffers_per_page;
  99         }
 100  out:
 101         return buf_pos;
 102 }
 103
 104 /*
 105  * Frees BUFFER memory for each of the pointers of the struct qdio_buffer array
 106  * in the adapter struct cur_buf is the pointer array and count can be any
 107  * number of buffers in the array that should be freed starting from buffer 0
 108  *
 109  * locks:       must only be called with zfcp_data.config_sema taken
 110  */
 111 static void
 112 zfcp_qdio_buffers_dequeue(struct qdio_buffer **cur_buf, int count)
 113 {
 114         int buf_pos;
 115         int qdio_buffers_per_page;
 116
 117         qdio_buffers_per_page = PAGE_SIZE / sizeof (struct qdio_buffer);
 118         ZFCP_LOG_TRACE("buffers_per_page=%d\n", qdio_buffers_per_page);
 119
 120         for (buf_pos = 0; buf_pos < count; buf_pos += qdio_buffers_per_page)
 121                 free_page((unsigned long) cur_buf[buf_pos]);
 122         return;
 123 }
 124
 125 /* locks:       must only be called with zfcp_data.config_sema taken */
 126 int
 127 zfcp_qdio_allocate_queues(struct zfcp_adapter *adapter)
 128 {
 129         int buffer_count;
 130         int retval = 0;
 131
 132         buffer_count =
 133             zfcp_qdio_buffers_enqueue(&(adapter->request_queue.buffer[0]),
 134                                       QDIO_MAX_BUFFERS_PER_Q);
 135         if (buffer_count < QDIO_MAX_BUFFERS_PER_Q) {
 136                 ZFCP_LOG_DEBUG("only %d QDIO buffers allocated for request "
 137                                "queue\n", buffer_count);
 138                 zfcp_qdio_buffers_dequeue(&(adapter->request_queue.buffer[0]),
 139                                           buffer_count);
 140                 retval = -ENOMEM;
 141                 goto out;
 142         }
 143
 144         buffer_count =
 145             zfcp_qdio_buffers_enqueue(&(adapter->response_queue.buffer[0]),
 146                                       QDIO_MAX_BUFFERS_PER_Q);
 147         if (buffer_count < QDIO_MAX_BUFFERS_PER_Q) {
 148                 ZFCP_LOG_DEBUG("only %d QDIO buffers allocated for response "
 149                                "queue", buffer_count);
 150                 zfcp_qdio_buffers_dequeue(&(adapter->response_queue.buffer[0]),
 151                                           buffer_count);
 152                 ZFCP_LOG_TRACE("freeing request_queue buffers\n");
 153                 zfcp_qdio_buffers_dequeue(&(adapter->request_queue.buffer[0]),
 154                                           QDIO_MAX_BUFFERS_PER_Q);
 155                 retval = -ENOMEM;
 156                 goto out;
 157         }
 158  out:
 159         return retval;
 160 }
 161
 162 /* locks:       must only be called with zfcp_data.config_sema taken */
 163 void
 164 zfcp_qdio_free_queues(struct zfcp_adapter *adapter)
 165 {
 166         ZFCP_LOG_TRACE("freeing request_queue buffers\n");
 167         zfcp_qdio_buffers_dequeue(&(adapter->request_queue.buffer[0]),
 168                                   QDIO_MAX_BUFFERS_PER_Q);
 169
 170         ZFCP_LOG_TRACE("freeing response_queue buffers\n");
 171         zfcp_qdio_buffers_dequeue(&(adapter->response_queue.buffer[0]),
 172                                   QDIO_MAX_BUFFERS_PER_Q);
 173 }
 174
 175 int
 176 zfcp_qdio_allocate(struct zfcp_adapter *adapter)
 177 {
 178         struct qdio_initialize *init_data;
 179
 180         init_data = &adapter->qdio_init_data;
 181
 182         init_data->cdev = adapter->ccw_device;
 183         init_data->q_format = QDIO_SCSI_QFMT;
 184         memcpy(init_data->adapter_name, &adapter->name, 8);
 185         init_data->qib_param_field_format = 0;
 186         init_data->qib_param_field = NULL;
 187         init_data->input_slib_elements = NULL;
 188         init_data->output_slib_elements = NULL;
 189         init_data->min_input_threshold = ZFCP_MIN_INPUT_THRESHOLD;
 190         init_data->max_input_threshold = ZFCP_MAX_INPUT_THRESHOLD;
 191         init_data->min_output_threshold = ZFCP_MIN_OUTPUT_THRESHOLD;
 192         init_data->max_output_threshold = ZFCP_MAX_OUTPUT_THRESHOLD;
 193         init_data->no_input_qs = 1;
 194         init_data->no_output_qs = 1;
 195         init_data->input_handler = zfcp_qdio_response_handler;
 196         init_data->output_handler = zfcp_qdio_request_handler;
 197         init_data->int_parm = (unsigned long) adapter;
 198         init_data->flags = QDIO_INBOUND_0COPY_SBALS |
 199             QDIO_OUTBOUND_0COPY_SBALS | QDIO_USE_OUTBOUND_PCIS;
 200         init_data->input_sbal_addr_array =
 201             (void **) (adapter->response_queue.buffer);
 202         init_data->output_sbal_addr_array =
 203             (void **) (adapter->request_queue.buffer);
 204
 205         return qdio_allocate(init_data);
 206 }
 207
 208 /*
 209  * function:    zfcp_qdio_handler_error_check
 210  *
 211  * purpose:     called by the response handler to determine error condition
 212  *
 213  * returns:     error flag
 214  *
 215  */
 216 static inline int
 217 zfcp_qdio_handler_error_check(struct zfcp_adapter *adapter,
 218                               unsigned int status,
 219                               unsigned int qdio_error, unsigned int siga_error)
 220 {
 221         int retval = 0;
 222
 223         if (ZFCP_LOG_CHECK(ZFCP_LOG_LEVEL_TRACE)) {
 224                 if (status & QDIO_STATUS_INBOUND_INT) {
 225                         ZFCP_LOG_TRACE("status is"
 226                                        " QDIO_STATUS_INBOUND_INT \n");
 227                 }
 228                 if (status & QDIO_STATUS_OUTBOUND_INT) {
 229                         ZFCP_LOG_TRACE("status is"
 230                                        " QDIO_STATUS_OUTBOUND_INT \n");
 231                 }
 232         }
 233         if (unlikely(status & QDIO_STATUS_LOOK_FOR_ERROR)) {
 234                 retval = -EIO;
 235
 236                 ZFCP_LOG_INFO("QDIO problem occurred (status=0x%x, "
 237                               "qdio_error=0x%x, siga_error=0x%x)\n",
 238                               status, qdio_error, siga_error);
 239
 240                 /* Restarting IO on the failed adapter from scratch */
 241                 debug_text_event(adapter->erp_dbf, 1, "qdio_err");
 242                /*
 243                 * Since we have been using this adapter, it is save to assume
 244                 * that it is not failed but recoverable. The card seems to
 245                 * report link-up events by self-initiated queue shutdown.
 246                 * That is why we need to clear the the link-down flag
 247                 * which is set again in case we have missed by a mile.
 248                 */
 249                zfcp_erp_adapter_reopen(
 250                        adapter,
 251                        ZFCP_STATUS_ADAPTER_LINK_UNPLUGGED |
 252                        ZFCP_STATUS_COMMON_ERP_FAILED);
 253         }
 254         return retval;
 255 }
 256
 257 /*
 258  * function:    zfcp_qdio_request_handler
 259  *
 260  * purpose:     is called by QDIO layer for completed SBALs in request queue
 261  *
 262  * returns:     (void)
 263  */
 264 static void
 265 zfcp_qdio_request_handler(struct ccw_device *ccw_device,
 266                           unsigned int status,
 267                           unsigned int qdio_error,
 268                           unsigned int siga_error,
 269                           unsigned int queue_number,
 270                           int first_element,
 271                           int elements_processed,
 272                           unsigned long int_parm)
 273 {
 274         struct zfcp_adapter *adapter;
 275         struct zfcp_qdio_queue *queue;
 276
 277         adapter = (struct zfcp_adapter *) int_parm;
 278         queue = &adapter->request_queue;
 279
 280         ZFCP_LOG_DEBUG("adapter %s, first=%d, elements_processed=%d\n",
 281                        zfcp_get_busid_by_adapter(adapter),
 282                        first_element, elements_processed);
 283
 284         if (unlikely(zfcp_qdio_handler_error_check(adapter, status, qdio_error,
 285                                                    siga_error)))
 286                 goto out;
 287         /*
 288          * we stored address of struct zfcp_adapter  data structure
 289          * associated with irq in int_parm
 290          */
 291
 292         /* cleanup all SBALs being program-owned now */
 293         zfcp_qdio_zero_sbals(queue->buffer, first_element, elements_processed);
 294
 295         /* increase free space in outbound queue */
 296         atomic_add(elements_processed, &queue->free_count);
 297         ZFCP_LOG_DEBUG("free_count=%d\n", atomic_read(&queue->free_count));
 298         wake_up(&adapter->request_wq);
 299         ZFCP_LOG_DEBUG("elements_processed=%d, free count=%d\n",
 300                        elements_processed, atomic_read(&queue->free_count));
 301  out:
 302         return;
 303 }
 304
 305 /*
 306  * function:    zfcp_qdio_response_handler
 307  *
 308  * purpose:     is called by QDIO layer for completed SBALs in response queue
 309  *
 310  * returns:     (void)
 311  */
 312 static void
 313 zfcp_qdio_response_handler(struct ccw_device *ccw_device,
 314                            unsigned int status,
 315                            unsigned int qdio_error,
 316                            unsigned int siga_error,
 317                            unsigned int queue_number,
 318                            int first_element,
 319                            int elements_processed,
 320                            unsigned long int_parm)
 321 {
 322         struct zfcp_adapter *adapter;
 323         struct zfcp_qdio_queue *queue;
 324         int buffer_index;
 325         int i;
 326         struct qdio_buffer *buffer;
 327         int retval = 0;
 328         u8 count;
 329         u8 start;
 330         volatile struct qdio_buffer_element *buffere = NULL;
 331         int buffere_index;
 332
 333         adapter = (struct zfcp_adapter *) int_parm;
 334         queue = &adapter->response_queue;
 335
 336         if (unlikely(zfcp_qdio_handler_error_check(adapter, status, qdio_error,
 337                                                    siga_error)))
 338                 goto out;
 339
 340         /*
 341          * we stored address of struct zfcp_adapter  data structure
 342          * associated with irq in int_parm
 343          */
 344
 345         buffere = &(queue->buffer[first_element]->element[0]);
 346         ZFCP_LOG_DEBUG("first BUFFERE flags=0x%x\n", buffere->flags);
 347         /*
 348          * go through all SBALs from input queue currently
 349          * returned by QDIO layer
 350          */
 351
 352         for (i = 0; i < elements_processed; i++) {
 353
 354                 buffer_index = first_element + i;
 355                 buffer_index %= QDIO_MAX_BUFFERS_PER_Q;
 356                 buffer = queue->buffer[buffer_index];
 357
 358                 /* go through all SBALEs of SBAL */
 359                 for (buffere_index = 0;
 360                      buffere_index < QDIO_MAX_ELEMENTS_PER_BUFFER;
 361                      buffere_index++) {
 362
 363                         /* look for QDIO request identifiers in SB */
 364                         buffere = &buffer->element[buffere_index];
 365                         retval = zfcp_qdio_reqid_check(adapter,
 366                                                        (void *) buffere->addr);
 367
 368                         if (retval) {
 369                                 ZFCP_LOG_NORMAL("bug: unexpected inbound "
 370                                                 "packet on adapter %s "
 371                                                 "(reqid=0x%lx, "
 372                                                 "first_element=%d, "
 373                                                 "elements_processed=%d)\n",
 374                                                 zfcp_get_busid_by_adapter(adapter),
 375                                                 (unsigned long) buffere->addr,
 376                                                 first_element,
 377                                                 elements_processed);
 378                                 ZFCP_LOG_NORMAL("hex dump of inbound buffer "
 379                                                 "at address %p "
 380                                                 "(buffer_index=%d, "
 381                                                 "buffere_index=%d)\n", buffer,
 382                                                 buffer_index, buffere_index);
 383                                 ZFCP_HEX_DUMP(ZFCP_LOG_LEVEL_NORMAL,
 384                                               (char *) buffer, SBAL_SIZE);
 385                         }
 386                         /*
 387                          * A single used SBALE per inbound SBALE has been
 388                          * implemented by QDIO so far. Hope they will
 389                          * do some optimisation. Will need to change to
 390                          * unlikely() then.
 391                          */
 392                         if (likely(buffere->flags & SBAL_FLAGS_LAST_ENTRY))
 393                                 break;
 394                 };
 395
 396                 if (unlikely(!(buffere->flags & SBAL_FLAGS_LAST_ENTRY))) {
 397                         ZFCP_LOG_NORMAL("bug: End of inbound data "
 398                                         "not marked!\n");
 399                 }
 400         }
 401
 402         /*
 403          * put range of SBALs back to response queue
 404          * (including SBALs which have already been free before)
 405          */
 406         count = atomic_read(&queue->free_count) + elements_processed;
 407         start = queue->free_index;
 408
 409         ZFCP_LOG_TRACE("calling do_QDIO on adapter %s (flags=0x%x, "
 410                        "queue_no=%i, index_in_queue=%i, count=%i, "
 411                        "buffers=0x%lx\n",
 412                        zfcp_get_busid_by_adapter(adapter),
 413                        QDIO_FLAG_SYNC_INPUT | QDIO_FLAG_UNDER_INTERRUPT,
 414                        0, start, count, (unsigned long) &queue->buffer[start]);
 415
 416         retval = do_QDIO(ccw_device,
 417                          QDIO_FLAG_SYNC_INPUT | QDIO_FLAG_UNDER_INTERRUPT,
 418                          0, start, count, NULL);
 419
 420         if (unlikely(retval)) {
 421                 atomic_set(&queue->free_count, count);
 422                 ZFCP_LOG_DEBUG("clearing of inbound data regions failed, "
 423                                "queues may be down "
 424                                "(count=%d, start=%d, retval=%d)\n",
 425                                count, start, retval);
 426         } else {
 427                 queue->free_index += count;
 428                 queue->free_index %= QDIO_MAX_BUFFERS_PER_Q;
 429                 atomic_set(&queue->free_count, 0);
 430                 ZFCP_LOG_TRACE("%i buffers enqueued to response "
 431                                "queue at position %i\n", count, start);
 432         }
 433  out:
 434         return;
 435 }
 436
 437 /*
 438  * function:    zfcp_qdio_reqid_check
 439  *
 440  * purpose:     checks for valid reqids or unsolicited status
 441  *
 442  * returns:     0 - valid request id or unsolicited status
 443  *              !0 - otherwise
 444  */
 445 int
 446 zfcp_qdio_reqid_check(struct zfcp_adapter *adapter, void *sbale_addr)
 447 {
 448         struct zfcp_fsf_req *fsf_req;
 449
 450         /* invalid (per convention used in this driver) */
 451         if (unlikely(!sbale_addr)) {
 452                 ZFCP_LOG_NORMAL("bug: invalid reqid\n");
 453                 return -EINVAL;
 454         }
 455
 456         /* valid request id and thus (hopefully :) valid fsf_req address */
 457         fsf_req = (struct zfcp_fsf_req *) sbale_addr;
 458
 459         /* serialize with zfcp_fsf_req_dismiss_all */
 460         spin_lock(&adapter->fsf_req_list_lock);
 461         if (list_empty(&adapter->fsf_req_list_head)) {
 462                 spin_unlock(&adapter->fsf_req_list_lock);
 463                 return 0;
 464         }
 465         list_del(&fsf_req->list);
 466         atomic_dec(&adapter->fsf_reqs_active);
 467         spin_unlock(&adapter->fsf_req_list_lock);
 468
 469         if (unlikely(adapter != fsf_req->adapter)) {
 470                 ZFCP_LOG_NORMAL("bug: invalid reqid (fsf_req=%p, "
 471                                 "fsf_req->adapter=%p, adapter=%p)\n",
 472                                 fsf_req, fsf_req->adapter, adapter);
 473                 return -EINVAL;
 474         }
 475
 476         /* finish the FSF request */
 477         zfcp_fsf_req_complete(fsf_req);
 478
 479         return 0;
 480 }
 481
 482 /**
 483  * zfcp_qdio_sbale_get - return pointer to SBALE of qdio_queue
 484  * @queue: queue from which SBALE should be returned
 485  * @sbal: specifies number of SBAL in queue
 486  * @sbale: specifes number of SBALE in SBAL
 487  */
 488 static inline volatile struct qdio_buffer_element *
 489 zfcp_qdio_sbale_get(struct zfcp_qdio_queue *queue, int sbal, int sbale)
 490 {
 491         return &queue->buffer[sbal]->element[sbale];
 492 }
 493
 494 /**
 495  * zfcp_qdio_sbale_req - return pointer to SBALE of request_queue for
 496  *      a struct zfcp_fsf_req
 497  */
 498 inline volatile struct qdio_buffer_element *
 499 zfcp_qdio_sbale_req(struct zfcp_fsf_req *fsf_req, int sbal, int sbale)
 500 {
 501         return zfcp_qdio_sbale_get(&fsf_req->adapter->request_queue,
 502                                    sbal, sbale);
 503 }
 504
 505 /**
 506  * zfcp_qdio_sbale_resp - return pointer to SBALE of response_queue for
 507  *      a struct zfcp_fsf_req
 508  */
 509 static inline volatile struct qdio_buffer_element *
 510 zfcp_qdio_sbale_resp(struct zfcp_fsf_req *fsf_req, int sbal, int sbale)
 511 {
 512         return zfcp_qdio_sbale_get(&fsf_req->adapter->response_queue,
 513                                    sbal, sbale);
 514 }
 515
 516 /**
 517  * zfcp_qdio_sbale_curr - return current SBALE on request_queue for
 518  *      a struct zfcp_fsf_req
 519  */
 520 inline volatile struct qdio_buffer_element *
 521 zfcp_qdio_sbale_curr(struct zfcp_fsf_req *fsf_req)
 522 {
 523         return zfcp_qdio_sbale_req(fsf_req, fsf_req->sbal_curr,
 524                                    fsf_req->sbale_curr);
 525 }
 526
 527 /**
 528  * zfcp_qdio_sbal_limit - determine maximum number of SBALs that can be used
 529  *      on the request_queue for a struct zfcp_fsf_req
 530  * @fsf_req: the number of the last SBAL that can be used is stored herein
 531  * @max_sbals: used to pass an upper limit for the number of SBALs
 532  *
 533  * Note: We can assume at least one free SBAL in the request_queue when called.
 534  */
 535 static inline void
 536 zfcp_qdio_sbal_limit(struct zfcp_fsf_req *fsf_req, int max_sbals)
 537 {
 538         int count = atomic_read(&fsf_req->adapter->request_queue.free_count);
 539         count = min(count, max_sbals);
 540         fsf_req->sbal_last  = fsf_req->sbal_first;
 541         fsf_req->sbal_last += (count - 1);
 542         fsf_req->sbal_last %= QDIO_MAX_BUFFERS_PER_Q;
 543 }
 544
 545 /**
 546  * zfcp_qdio_sbal_chain - chain SBALs if more than one SBAL is needed for a
 547  *      request
 548  * @fsf_req: zfcp_fsf_req to be processed
 549  * @sbtype: SBAL flags which have to be set in first SBALE of new SBAL
 550  *
 551  * This function changes sbal_curr, sbale_curr, sbal_number of fsf_req.
 552  */
 553 static inline volatile struct qdio_buffer_element *
 554 zfcp_qdio_sbal_chain(struct zfcp_fsf_req *fsf_req, unsigned long sbtype)
 555 {
 556         volatile struct qdio_buffer_element *sbale;
 557
 558         /* set last entry flag in current SBALE of current SBAL */
 559         sbale = zfcp_qdio_sbale_curr(fsf_req);
 560         sbale->flags |= SBAL_FLAGS_LAST_ENTRY;
 561
 562         /* don't exceed last allowed SBAL */
 563         if (fsf_req->sbal_curr == fsf_req->sbal_last)
 564                 return NULL;
 565
 566         /* set chaining flag in first SBALE of current SBAL */
 567         sbale = zfcp_qdio_sbale_req(fsf_req, fsf_req->sbal_curr, 0);
 568         sbale->flags |= SBAL_FLAGS0_MORE_SBALS;
 569
 570         /* calculate index of next SBAL */
 571         fsf_req->sbal_curr++;
 572         fsf_req->sbal_curr %= QDIO_MAX_BUFFERS_PER_Q;
 573
 574         /* keep this requests number of SBALs up-to-date */
 575         fsf_req->sbal_number++;
 576
 577         /* start at first SBALE of new SBAL */
 578         fsf_req->sbale_curr = 0;
 579
 580         /* set storage-block type for new SBAL */
 581         sbale = zfcp_qdio_sbale_curr(fsf_req);
 582         sbale->flags |= sbtype;
 583
 584         return sbale;
 585 }
 586
 587 /**
 588  * zfcp_qdio_sbale_next - switch to next SBALE, chain SBALs if needed
 589  */
 590 static inline volatile struct qdio_buffer_element *
 591 zfcp_qdio_sbale_next(struct zfcp_fsf_req *fsf_req, unsigned long sbtype)
 592 {
 593         if (fsf_req->sbale_curr == ZFCP_LAST_SBALE_PER_SBAL)
 594                 return zfcp_qdio_sbal_chain(fsf_req, sbtype);
 595
 596         fsf_req->sbale_curr++;
 597
 598         return zfcp_qdio_sbale_curr(fsf_req);
 599 }
 600
 601 /**
 602  * zfcp_qdio_sbals_zero - initialize SBALs between first and last in queue
 603  *      with zero from
 604  */
 605 static inline int
 606 zfcp_qdio_sbals_zero(struct zfcp_qdio_queue *queue, int first, int last)
 607 {
 608         struct qdio_buffer **buf = queue->buffer;
 609         int curr = first;
 610         int count = 0;
 611
 612         for(;;) {
 613                 curr %= QDIO_MAX_BUFFERS_PER_Q;
 614                 count++;
 615                 memset(buf[curr], 0, sizeof(struct qdio_buffer));
 616                 if (curr == last)
 617                         break;
 618                 curr++;
 619         }
 620         return count;
 621 }
 622
 623
 624 /**
 625  * zfcp_qdio_sbals_wipe - reset all changes in SBALs for an fsf_req
 626  */
 627 static inline int
 628 zfcp_qdio_sbals_wipe(struct zfcp_fsf_req *fsf_req)
 629 {
 630         return zfcp_qdio_sbals_zero(&fsf_req->adapter->request_queue,
 631                                     fsf_req->sbal_first, fsf_req->sbal_curr);
 632 }
 633
 634
 635 /**
 636  * zfcp_qdio_sbale_fill - set address and lenght in current SBALE
 637  *      on request_queue
 638  */
 639 static inline void
 640 zfcp_qdio_sbale_fill(struct zfcp_fsf_req *fsf_req, unsigned long sbtype,
 641                      void *addr, int length)
 642 {
 643         volatile struct qdio_buffer_element *sbale;
 644
 645         sbale = zfcp_qdio_sbale_curr(fsf_req);
 646         sbale->addr = addr;
 647         sbale->length = length;
 648 }
 649
 650 /**
 651  * zfcp_qdio_sbals_from_segment - map memory segment to SBALE(s)
 652  * @fsf_req: request to be processed
 653  * @sbtype: SBALE flags
 654  * @start_addr: address of memory segment
 655  * @total_length: length of memory segment
 656  *
 657  * Alignment and length of the segment determine how many SBALEs are needed
 658  * for the memory segment.
 659  */
 660 static inline int
 661 zfcp_qdio_sbals_from_segment(struct zfcp_fsf_req *fsf_req, unsigned long sbtype,
 662                              void *start_addr, unsigned long total_length)
 663 {
 664         unsigned long remaining, length;
 665         void *addr;
 666
 667         /* split segment up heeding page boundaries */
 668         for (addr = start_addr, remaining = total_length; remaining > 0;
 669              addr += length, remaining -= length) {
 670                 /* get next free SBALE for new piece */
 671                 if (NULL == zfcp_qdio_sbale_next(fsf_req, sbtype)) {
 672                         /* no SBALE left, clean up and leave */
 673                         zfcp_qdio_sbals_wipe(fsf_req);
 674                         return -EINVAL;
 675                 }
 676                 /* calculate length of new piece */
 677                 length = min(remaining,
 678                              (PAGE_SIZE - ((unsigned long) addr &
 679                                            (PAGE_SIZE - 1))));
 680                 /* fill current SBALE with calculated piece */
 681                 zfcp_qdio_sbale_fill(fsf_req, sbtype, addr, length);
 682         }
 683         return total_length;
 684 }
 685
 686
 687 /**
 688  * zfcp_qdio_sbals_from_sg - fill SBALs from scatter-gather list
 689  * @fsf_req: request to be processed
 690  * @sbtype: SBALE flags
 691  * @sg: scatter-gather list
 692  * @sg_count: number of elements in scatter-gather list
 693  * @max_sbals: upper bound for number of SBALs to be used
 694  */
 695 inline int
 696 zfcp_qdio_sbals_from_sg(struct zfcp_fsf_req *fsf_req, unsigned long sbtype,
 697                         struct scatterlist *sg, int sg_count, int max_sbals)
 698 {
 699         int sg_index;
 700         struct scatterlist *sg_segment;
 701         int retval;
 702         volatile struct qdio_buffer_element *sbale;
 703         int bytes = 0;
 704
 705         /* figure out last allowed SBAL */
 706         zfcp_qdio_sbal_limit(fsf_req, max_sbals);
 707
 708         /* set storage-block type for current SBAL */
 709         sbale = zfcp_qdio_sbale_req(fsf_req, fsf_req->sbal_curr, 0);
 710         sbale->flags |= sbtype;
 711
 712         /* process all segements of scatter-gather list */
 713         for (sg_index = 0, sg_segment = sg, bytes = 0;
 714              sg_index < sg_count;
 715              sg_index++, sg_segment++) {
 716                 retval = zfcp_qdio_sbals_from_segment(
 717                                 fsf_req,
 718                                 sbtype,
 719                                 zfcp_sg_to_address(sg_segment),
 720                                 sg_segment->length);
 721                 if (retval < 0) {
 722                         bytes = retval;
 723                         goto out;
 724                 } else
 725                         bytes += retval;
 726         }
 727         /* assume that no other SBALEs are to follow in the same SBAL */
 728         sbale = zfcp_qdio_sbale_curr(fsf_req);
 729         sbale->flags |= SBAL_FLAGS_LAST_ENTRY;
 730 out:
 731         return bytes;
 732 }
 733
 734
 735 /**
 736  * zfcp_qdio_sbals_from_buffer - fill SBALs from buffer
 737  * @fsf_req: request to be processed
 738  * @sbtype: SBALE flags
 739  * @buffer: data buffer
 740  * @length: length of buffer
 741  * @max_sbals: upper bound for number of SBALs to be used
 742  */
 743 static inline int
 744 zfcp_qdio_sbals_from_buffer(struct zfcp_fsf_req *fsf_req, unsigned long sbtype,
 745                             void *buffer, unsigned long length, int max_sbals)
 746 {
 747         struct scatterlist sg_segment;
 748
 749         zfcp_address_to_sg(buffer, &sg_segment);
 750         sg_segment.length = length;
 751
 752         return zfcp_qdio_sbals_from_sg(fsf_req, sbtype, &sg_segment, 1,
 753                                        max_sbals);
 754 }
 755
 756
 757 /**
 758  * zfcp_qdio_sbals_from_scsicmnd - fill SBALs from scsi command
 759  * @fsf_req: request to be processed
 760  * @sbtype: SBALE flags
 761  * @scsi_cmnd: either scatter-gather list or buffer contained herein is used
 762  *      to fill SBALs
 763  */
 764 inline int
 765 zfcp_qdio_sbals_from_scsicmnd(struct zfcp_fsf_req *fsf_req,
 766                               unsigned long sbtype, struct scsi_cmnd *scsi_cmnd)
 767 {
 768         if (scsi_cmnd->use_sg) {
 769                 return zfcp_qdio_sbals_from_sg(fsf_req, sbtype,
 770                                                (struct scatterlist *)
 771                                                scsi_cmnd->request_buffer,
 772                                                scsi_cmnd->use_sg,
 773                                                ZFCP_MAX_SBALS_PER_REQ);
 774         } else {
 775                 return zfcp_qdio_sbals_from_buffer(fsf_req, sbtype,
 776                                                    scsi_cmnd->request_buffer,
 777                                                    scsi_cmnd->request_bufflen,
 778                                                    ZFCP_MAX_SBALS_PER_REQ);
 779         }
 780 }
 781
 782 /**
 783  * zfcp_qdio_determine_pci - set PCI flag in first SBALE on qdio queue if needed
 784  */
 785 int
 786 zfcp_qdio_determine_pci(struct zfcp_qdio_queue *req_queue,
 787                         struct zfcp_fsf_req *fsf_req)
 788 {
 789         int new_distance_from_int;
 790         int pci_pos;
 791         volatile struct qdio_buffer_element *sbale;
 792
 793         new_distance_from_int = req_queue->distance_from_int +
 794                 fsf_req->sbal_number;
 795
 796         if (unlikely(new_distance_from_int >= ZFCP_QDIO_PCI_INTERVAL)) {
 797                 new_distance_from_int %= ZFCP_QDIO_PCI_INTERVAL;
 798                 pci_pos  = fsf_req->sbal_first;
 799                 pci_pos += fsf_req->sbal_number;
 800                 pci_pos -= new_distance_from_int;
 801                 pci_pos -= 1;
 802                 pci_pos %= QDIO_MAX_BUFFERS_PER_Q;
 803                 sbale = zfcp_qdio_sbale_req(fsf_req, pci_pos, 0);
 804                 sbale->flags |= SBAL_FLAGS0_PCI;
 805         }
 806         return new_distance_from_int;
 807 }
 808
 809 /*
 810  * function:    zfcp_zero_sbals
 811  *
 812  * purpose:     zeros specified range of SBALs
 813  *
 814  * returns:
 815  */
 816 void
 817 zfcp_qdio_zero_sbals(struct qdio_buffer *buf[], int first, int clean_count)
 818 {
 819         int cur_pos;
 820         int index;
 821
 822         for (cur_pos = first; cur_pos < (first + clean_count); cur_pos++) {
 823                 index = cur_pos % QDIO_MAX_BUFFERS_PER_Q;
 824                 memset(buf[index], 0, sizeof (struct qdio_buffer));
 825                 ZFCP_LOG_TRACE("zeroing BUFFER %d at address %p\n",
 826                                index, buf[index]);
 827         }
 828 }
 829
 830 #undef ZFCP_LOG_AREA