xref: /linux/drivers/s390/scsi/zfcp_qdio.c (revision 2b8232ce512105e28453f301d1510de8363bccd1)
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(
178                        adapter,
179                        ZFCP_STATUS_ADAPTER_LINK_UNPLUGGED |
180                        ZFCP_STATUS_COMMON_ERP_FAILED);
181 	}
182 	return retval;
183 }
184 
185 /*
186  * function:    zfcp_qdio_request_handler
187  *
188  * purpose:	is called by QDIO layer for completed SBALs in request queue
189  *
190  * returns:	(void)
191  */
192 static void
193 zfcp_qdio_request_handler(struct ccw_device *ccw_device,
194 			  unsigned int status,
195 			  unsigned int qdio_error,
196 			  unsigned int siga_error,
197 			  unsigned int queue_number,
198 			  int first_element,
199 			  int elements_processed,
200 			  unsigned long int_parm)
201 {
202 	struct zfcp_adapter *adapter;
203 	struct zfcp_qdio_queue *queue;
204 
205 	adapter = (struct zfcp_adapter *) int_parm;
206 	queue = &adapter->request_queue;
207 
208 	ZFCP_LOG_DEBUG("adapter %s, first=%d, elements_processed=%d\n",
209 		       zfcp_get_busid_by_adapter(adapter),
210 		       first_element, elements_processed);
211 
212 	if (unlikely(zfcp_qdio_handler_error_check(adapter, status, qdio_error,
213 						   siga_error, first_element,
214 						   elements_processed)))
215 		goto out;
216 	/*
217 	 * we stored address of struct zfcp_adapter  data structure
218 	 * associated with irq in int_parm
219 	 */
220 
221 	/* cleanup all SBALs being program-owned now */
222 	zfcp_qdio_zero_sbals(queue->buffer, first_element, elements_processed);
223 
224 	/* increase free space in outbound queue */
225 	atomic_add(elements_processed, &queue->free_count);
226 	ZFCP_LOG_DEBUG("free_count=%d\n", atomic_read(&queue->free_count));
227 	wake_up(&adapter->request_wq);
228 	ZFCP_LOG_DEBUG("elements_processed=%d, free count=%d\n",
229 		       elements_processed, atomic_read(&queue->free_count));
230  out:
231 	return;
232 }
233 
234 /**
235  * zfcp_qdio_reqid_check - checks for valid reqids.
236  */
237 static void zfcp_qdio_reqid_check(struct zfcp_adapter *adapter,
238 				  unsigned long req_id)
239 {
240 	struct zfcp_fsf_req *fsf_req;
241 	unsigned long flags;
242 
243 	debug_long_event(adapter->erp_dbf, 4, req_id);
244 
245 	spin_lock_irqsave(&adapter->req_list_lock, flags);
246 	fsf_req = zfcp_reqlist_find(adapter, req_id);
247 
248 	if (!fsf_req)
249 		/*
250 		 * Unknown request means that we have potentially memory
251 		 * corruption and must stop the machine immediatly.
252 		 */
253 		panic("error: unknown request id (%ld) on adapter %s.\n",
254 		      req_id, zfcp_get_busid_by_adapter(adapter));
255 
256 	zfcp_reqlist_remove(adapter, fsf_req);
257 	atomic_dec(&adapter->reqs_active);
258 	spin_unlock_irqrestore(&adapter->req_list_lock, flags);
259 
260 	/* finish the FSF request */
261 	zfcp_fsf_req_complete(fsf_req);
262 }
263 
264 /*
265  * function:   	zfcp_qdio_response_handler
266  *
267  * purpose:	is called by QDIO layer for completed SBALs in response queue
268  *
269  * returns:	(void)
270  */
271 static void
272 zfcp_qdio_response_handler(struct ccw_device *ccw_device,
273 			   unsigned int status,
274 			   unsigned int qdio_error,
275 			   unsigned int siga_error,
276 			   unsigned int queue_number,
277 			   int first_element,
278 			   int elements_processed,
279 			   unsigned long int_parm)
280 {
281 	struct zfcp_adapter *adapter;
282 	struct zfcp_qdio_queue *queue;
283 	int buffer_index;
284 	int i;
285 	struct qdio_buffer *buffer;
286 	int retval = 0;
287 	u8 count;
288 	u8 start;
289 	volatile struct qdio_buffer_element *buffere = NULL;
290 	int buffere_index;
291 
292 	adapter = (struct zfcp_adapter *) int_parm;
293 	queue = &adapter->response_queue;
294 
295 	if (unlikely(zfcp_qdio_handler_error_check(adapter, status, qdio_error,
296 						   siga_error, first_element,
297 						   elements_processed)))
298 		goto out;
299 
300 	/*
301 	 * we stored address of struct zfcp_adapter  data structure
302 	 * associated with irq in int_parm
303 	 */
304 
305 	buffere = &(queue->buffer[first_element]->element[0]);
306 	ZFCP_LOG_DEBUG("first BUFFERE flags=0x%x\n", buffere->flags);
307 	/*
308 	 * go through all SBALs from input queue currently
309 	 * returned by QDIO layer
310 	 */
311 
312 	for (i = 0; i < elements_processed; i++) {
313 
314 		buffer_index = first_element + i;
315 		buffer_index %= QDIO_MAX_BUFFERS_PER_Q;
316 		buffer = queue->buffer[buffer_index];
317 
318 		/* go through all SBALEs of SBAL */
319 		for (buffere_index = 0;
320 		     buffere_index < QDIO_MAX_ELEMENTS_PER_BUFFER;
321 		     buffere_index++) {
322 
323 			/* look for QDIO request identifiers in SB */
324 			buffere = &buffer->element[buffere_index];
325 			zfcp_qdio_reqid_check(adapter,
326 					      (unsigned long) buffere->addr);
327 
328 			/*
329 			 * A single used SBALE per inbound SBALE has been
330 			 * implemented by QDIO so far. Hope they will
331 			 * do some optimisation. Will need to change to
332 			 * unlikely() then.
333 			 */
334 			if (likely(buffere->flags & SBAL_FLAGS_LAST_ENTRY))
335 				break;
336 		};
337 
338 		if (unlikely(!(buffere->flags & SBAL_FLAGS_LAST_ENTRY))) {
339 			ZFCP_LOG_NORMAL("bug: End of inbound data "
340 					"not marked!\n");
341 		}
342 	}
343 
344 	/*
345 	 * put range of SBALs back to response queue
346 	 * (including SBALs which have already been free before)
347 	 */
348 	count = atomic_read(&queue->free_count) + elements_processed;
349 	start = queue->free_index;
350 
351 	ZFCP_LOG_TRACE("calling do_QDIO on adapter %s (flags=0x%x, "
352 		       "queue_no=%i, index_in_queue=%i, count=%i, "
353 		       "buffers=0x%lx\n",
354 		       zfcp_get_busid_by_adapter(adapter),
355 		       QDIO_FLAG_SYNC_INPUT | QDIO_FLAG_UNDER_INTERRUPT,
356 		       0, start, count, (unsigned long) &queue->buffer[start]);
357 
358 	retval = do_QDIO(ccw_device,
359 			 QDIO_FLAG_SYNC_INPUT | QDIO_FLAG_UNDER_INTERRUPT,
360 			 0, start, count, NULL);
361 
362 	if (unlikely(retval)) {
363 		atomic_set(&queue->free_count, count);
364 		ZFCP_LOG_DEBUG("clearing of inbound data regions failed, "
365 			       "queues may be down "
366 			       "(count=%d, start=%d, retval=%d)\n",
367 			       count, start, retval);
368 	} else {
369 		queue->free_index += count;
370 		queue->free_index %= QDIO_MAX_BUFFERS_PER_Q;
371 		atomic_set(&queue->free_count, 0);
372 		ZFCP_LOG_TRACE("%i buffers enqueued to response "
373 			       "queue at position %i\n", count, start);
374 	}
375  out:
376 	return;
377 }
378 
379 /**
380  * zfcp_qdio_sbale_get - return pointer to SBALE of qdio_queue
381  * @queue: queue from which SBALE should be returned
382  * @sbal: specifies number of SBAL in queue
383  * @sbale: specifes number of SBALE in SBAL
384  */
385 static inline volatile struct qdio_buffer_element *
386 zfcp_qdio_sbale_get(struct zfcp_qdio_queue *queue, int sbal, int sbale)
387 {
388 	return &queue->buffer[sbal]->element[sbale];
389 }
390 
391 /**
392  * zfcp_qdio_sbale_req - return pointer to SBALE of request_queue for
393  *	a struct zfcp_fsf_req
394  */
395 volatile struct qdio_buffer_element *
396 zfcp_qdio_sbale_req(struct zfcp_fsf_req *fsf_req, int sbal, int sbale)
397 {
398 	return zfcp_qdio_sbale_get(&fsf_req->adapter->request_queue,
399 				   sbal, sbale);
400 }
401 
402 /**
403  * zfcp_qdio_sbale_resp - return pointer to SBALE of response_queue for
404  *	a struct zfcp_fsf_req
405  */
406 static inline volatile struct qdio_buffer_element *
407 zfcp_qdio_sbale_resp(struct zfcp_fsf_req *fsf_req, int sbal, int sbale)
408 {
409 	return zfcp_qdio_sbale_get(&fsf_req->adapter->response_queue,
410 				   sbal, sbale);
411 }
412 
413 /**
414  * zfcp_qdio_sbale_curr - return current SBALE on request_queue for
415  *	a struct zfcp_fsf_req
416  */
417 volatile struct qdio_buffer_element *
418 zfcp_qdio_sbale_curr(struct zfcp_fsf_req *fsf_req)
419 {
420 	return zfcp_qdio_sbale_req(fsf_req, fsf_req->sbal_curr,
421 				   fsf_req->sbale_curr);
422 }
423 
424 /**
425  * zfcp_qdio_sbal_limit - determine maximum number of SBALs that can be used
426  *	on the request_queue for a struct zfcp_fsf_req
427  * @fsf_req: the number of the last SBAL that can be used is stored herein
428  * @max_sbals: used to pass an upper limit for the number of SBALs
429  *
430  * Note: We can assume at least one free SBAL in the request_queue when called.
431  */
432 static void
433 zfcp_qdio_sbal_limit(struct zfcp_fsf_req *fsf_req, int max_sbals)
434 {
435 	int count = atomic_read(&fsf_req->adapter->request_queue.free_count);
436 	count = min(count, max_sbals);
437 	fsf_req->sbal_last  = fsf_req->sbal_first;
438 	fsf_req->sbal_last += (count - 1);
439 	fsf_req->sbal_last %= QDIO_MAX_BUFFERS_PER_Q;
440 }
441 
442 /**
443  * zfcp_qdio_sbal_chain - chain SBALs if more than one SBAL is needed for a
444  *	request
445  * @fsf_req: zfcp_fsf_req to be processed
446  * @sbtype: SBAL flags which have to be set in first SBALE of new SBAL
447  *
448  * This function changes sbal_curr, sbale_curr, sbal_number of fsf_req.
449  */
450 static volatile struct qdio_buffer_element *
451 zfcp_qdio_sbal_chain(struct zfcp_fsf_req *fsf_req, unsigned long sbtype)
452 {
453 	volatile struct qdio_buffer_element *sbale;
454 
455 	/* set last entry flag in current SBALE of current SBAL */
456 	sbale = zfcp_qdio_sbale_curr(fsf_req);
457 	sbale->flags |= SBAL_FLAGS_LAST_ENTRY;
458 
459 	/* don't exceed last allowed SBAL */
460 	if (fsf_req->sbal_curr == fsf_req->sbal_last)
461 		return NULL;
462 
463 	/* set chaining flag in first SBALE of current SBAL */
464 	sbale = zfcp_qdio_sbale_req(fsf_req, fsf_req->sbal_curr, 0);
465 	sbale->flags |= SBAL_FLAGS0_MORE_SBALS;
466 
467 	/* calculate index of next SBAL */
468 	fsf_req->sbal_curr++;
469 	fsf_req->sbal_curr %= QDIO_MAX_BUFFERS_PER_Q;
470 
471 	/* keep this requests number of SBALs up-to-date */
472 	fsf_req->sbal_number++;
473 
474 	/* start at first SBALE of new SBAL */
475 	fsf_req->sbale_curr = 0;
476 
477 	/* set storage-block type for new SBAL */
478 	sbale = zfcp_qdio_sbale_curr(fsf_req);
479 	sbale->flags |= sbtype;
480 
481 	return sbale;
482 }
483 
484 /**
485  * zfcp_qdio_sbale_next - switch to next SBALE, chain SBALs if needed
486  */
487 static volatile struct qdio_buffer_element *
488 zfcp_qdio_sbale_next(struct zfcp_fsf_req *fsf_req, unsigned long sbtype)
489 {
490 	if (fsf_req->sbale_curr == ZFCP_LAST_SBALE_PER_SBAL)
491 		return zfcp_qdio_sbal_chain(fsf_req, sbtype);
492 
493 	fsf_req->sbale_curr++;
494 
495 	return zfcp_qdio_sbale_curr(fsf_req);
496 }
497 
498 /**
499  * zfcp_qdio_sbals_zero - initialize SBALs between first and last in queue
500  *	with zero from
501  */
502 static int
503 zfcp_qdio_sbals_zero(struct zfcp_qdio_queue *queue, int first, int last)
504 {
505 	struct qdio_buffer **buf = queue->buffer;
506 	int curr = first;
507 	int count = 0;
508 
509 	for(;;) {
510 		curr %= QDIO_MAX_BUFFERS_PER_Q;
511 		count++;
512 		memset(buf[curr], 0, sizeof(struct qdio_buffer));
513 		if (curr == last)
514 			break;
515 		curr++;
516 	}
517 	return count;
518 }
519 
520 
521 /**
522  * zfcp_qdio_sbals_wipe - reset all changes in SBALs for an fsf_req
523  */
524 static inline int
525 zfcp_qdio_sbals_wipe(struct zfcp_fsf_req *fsf_req)
526 {
527 	return zfcp_qdio_sbals_zero(&fsf_req->adapter->request_queue,
528 				    fsf_req->sbal_first, fsf_req->sbal_curr);
529 }
530 
531 
532 /**
533  * zfcp_qdio_sbale_fill - set address and lenght in current SBALE
534  *	on request_queue
535  */
536 static void
537 zfcp_qdio_sbale_fill(struct zfcp_fsf_req *fsf_req, unsigned long sbtype,
538 		     void *addr, int length)
539 {
540 	volatile struct qdio_buffer_element *sbale;
541 
542 	sbale = zfcp_qdio_sbale_curr(fsf_req);
543 	sbale->addr = addr;
544 	sbale->length = length;
545 }
546 
547 /**
548  * zfcp_qdio_sbals_from_segment - map memory segment to SBALE(s)
549  * @fsf_req: request to be processed
550  * @sbtype: SBALE flags
551  * @start_addr: address of memory segment
552  * @total_length: length of memory segment
553  *
554  * Alignment and length of the segment determine how many SBALEs are needed
555  * for the memory segment.
556  */
557 static int
558 zfcp_qdio_sbals_from_segment(struct zfcp_fsf_req *fsf_req, unsigned long sbtype,
559 			     void *start_addr, unsigned long total_length)
560 {
561 	unsigned long remaining, length;
562 	void *addr;
563 
564 	/* split segment up heeding page boundaries */
565 	for (addr = start_addr, remaining = total_length; remaining > 0;
566 	     addr += length, remaining -= length) {
567 		/* get next free SBALE for new piece */
568 		if (NULL == zfcp_qdio_sbale_next(fsf_req, sbtype)) {
569 			/* no SBALE left, clean up and leave */
570 			zfcp_qdio_sbals_wipe(fsf_req);
571 			return -EINVAL;
572 		}
573 		/* calculate length of new piece */
574 		length = min(remaining,
575 			     (PAGE_SIZE - ((unsigned long) addr &
576 					   (PAGE_SIZE - 1))));
577 		/* fill current SBALE with calculated piece */
578 		zfcp_qdio_sbale_fill(fsf_req, sbtype, addr, length);
579 	}
580 	return total_length;
581 }
582 
583 
584 /**
585  * zfcp_qdio_sbals_from_sg - fill SBALs from scatter-gather list
586  * @fsf_req: request to be processed
587  * @sbtype: SBALE flags
588  * @sg: scatter-gather list
589  * @sg_count: number of elements in scatter-gather list
590  * @max_sbals: upper bound for number of SBALs to be used
591  */
592 int
593 zfcp_qdio_sbals_from_sg(struct zfcp_fsf_req *fsf_req, unsigned long sbtype,
594                         struct scatterlist *sg,	int sg_count, int max_sbals)
595 {
596 	int sg_index;
597 	struct scatterlist *sg_segment;
598 	int retval;
599 	volatile struct qdio_buffer_element *sbale;
600 	int bytes = 0;
601 
602 	/* figure out last allowed SBAL */
603 	zfcp_qdio_sbal_limit(fsf_req, max_sbals);
604 
605 	/* set storage-block type for current SBAL */
606 	sbale = zfcp_qdio_sbale_req(fsf_req, fsf_req->sbal_curr, 0);
607 	sbale->flags |= sbtype;
608 
609 	/* process all segements of scatter-gather list */
610 	for (sg_index = 0, sg_segment = sg, bytes = 0;
611 	     sg_index < sg_count;
612 	     sg_index++, sg_segment++) {
613 		retval = zfcp_qdio_sbals_from_segment(
614 				fsf_req,
615 				sbtype,
616 				zfcp_sg_to_address(sg_segment),
617 				sg_segment->length);
618 		if (retval < 0) {
619 			bytes = retval;
620 			goto out;
621 		} else
622                         bytes += retval;
623 	}
624 	/* assume that no other SBALEs are to follow in the same SBAL */
625 	sbale = zfcp_qdio_sbale_curr(fsf_req);
626 	sbale->flags |= SBAL_FLAGS_LAST_ENTRY;
627 out:
628 	return bytes;
629 }
630 
631 
632 /**
633  * zfcp_qdio_sbals_from_scsicmnd - fill SBALs from scsi command
634  * @fsf_req: request to be processed
635  * @sbtype: SBALE flags
636  * @scsi_cmnd: either scatter-gather list or buffer contained herein is used
637  *	to fill SBALs
638  */
639 int
640 zfcp_qdio_sbals_from_scsicmnd(struct zfcp_fsf_req *fsf_req,
641 			      unsigned long sbtype, struct scsi_cmnd *scsi_cmnd)
642 {
643 	return zfcp_qdio_sbals_from_sg(fsf_req,	sbtype, scsi_sglist(scsi_cmnd),
644 				       scsi_sg_count(scsi_cmnd),
645 				       ZFCP_MAX_SBALS_PER_REQ);
646 }
647 
648 /**
649  * zfcp_qdio_determine_pci - set PCI flag in first SBALE on qdio queue if needed
650  */
651 int
652 zfcp_qdio_determine_pci(struct zfcp_qdio_queue *req_queue,
653 			struct zfcp_fsf_req *fsf_req)
654 {
655 	int new_distance_from_int;
656 	int pci_pos;
657 	volatile struct qdio_buffer_element *sbale;
658 
659 	new_distance_from_int = req_queue->distance_from_int +
660                 fsf_req->sbal_number;
661 
662 	if (unlikely(new_distance_from_int >= ZFCP_QDIO_PCI_INTERVAL)) {
663 		new_distance_from_int %= ZFCP_QDIO_PCI_INTERVAL;
664                 pci_pos  = fsf_req->sbal_first;
665 		pci_pos += fsf_req->sbal_number;
666 		pci_pos -= new_distance_from_int;
667 		pci_pos -= 1;
668 		pci_pos %= QDIO_MAX_BUFFERS_PER_Q;
669 		sbale = zfcp_qdio_sbale_req(fsf_req, pci_pos, 0);
670 		sbale->flags |= SBAL_FLAGS0_PCI;
671 	}
672 	return new_distance_from_int;
673 }
674 
675 /*
676  * function:	zfcp_zero_sbals
677  *
678  * purpose:	zeros specified range of SBALs
679  *
680  * returns:
681  */
682 void
683 zfcp_qdio_zero_sbals(struct qdio_buffer *buf[], int first, int clean_count)
684 {
685 	int cur_pos;
686 	int index;
687 
688 	for (cur_pos = first; cur_pos < (first + clean_count); cur_pos++) {
689 		index = cur_pos % QDIO_MAX_BUFFERS_PER_Q;
690 		memset(buf[index], 0, sizeof (struct qdio_buffer));
691 		ZFCP_LOG_TRACE("zeroing BUFFER %d at address %p\n",
692 			       index, buf[index]);
693 	}
694 }
695 
696 #undef ZFCP_LOG_AREA
697