xref: /openbmc/linux/drivers/s390/scsi/zfcp_qdio.c (revision 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2)
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 	}			// if (ZFCP_LOG_CHECK(ZFCP_LOG_LEVEL_TRACE))
233 	if (unlikely(status & QDIO_STATUS_LOOK_FOR_ERROR)) {
234 		retval = -EIO;
235 
236 		ZFCP_LOG_FLAGS(1, "QDIO_STATUS_LOOK_FOR_ERROR \n");
237 
238 		ZFCP_LOG_INFO("QDIO problem occurred (status=0x%x, "
239 			      "qdio_error=0x%x, siga_error=0x%x)\n",
240 			      status, qdio_error, siga_error);
241 
242 		if (status & QDIO_STATUS_ACTIVATE_CHECK_CONDITION) {
243 			ZFCP_LOG_FLAGS(2,
244 				       "QDIO_STATUS_ACTIVATE_CHECK_CONDITION\n");
245 		}
246 		if (status & QDIO_STATUS_MORE_THAN_ONE_QDIO_ERROR) {
247 			ZFCP_LOG_FLAGS(2,
248 				       "QDIO_STATUS_MORE_THAN_ONE_QDIO_ERROR\n");
249 		}
250 		if (status & QDIO_STATUS_MORE_THAN_ONE_SIGA_ERROR) {
251 			ZFCP_LOG_FLAGS(2,
252 				       "QDIO_STATUS_MORE_THAN_ONE_SIGA_ERROR\n");
253 		}
254 
255 		if (siga_error & QDIO_SIGA_ERROR_ACCESS_EXCEPTION) {
256 			ZFCP_LOG_FLAGS(2, "QDIO_SIGA_ERROR_ACCESS_EXCEPTION\n");
257 		}
258 
259 		if (siga_error & QDIO_SIGA_ERROR_B_BIT_SET) {
260 			ZFCP_LOG_FLAGS(2, "QDIO_SIGA_ERROR_B_BIT_SET\n");
261 		}
262 
263 		switch (qdio_error) {
264 		case 0:
265 			ZFCP_LOG_FLAGS(3, "QDIO_OK");
266 			break;
267 		case SLSB_P_INPUT_ERROR:
268 			ZFCP_LOG_FLAGS(1, "SLSB_P_INPUT_ERROR\n");
269 			break;
270 		case SLSB_P_OUTPUT_ERROR:
271 			ZFCP_LOG_FLAGS(1, "SLSB_P_OUTPUT_ERROR\n");
272 			break;
273 		default:
274 			ZFCP_LOG_NORMAL("bug: unknown QDIO error 0x%x\n",
275 					qdio_error);
276 			break;
277 		}
278 		/* Restarting IO on the failed adapter from scratch */
279 		debug_text_event(adapter->erp_dbf, 1, "qdio_err");
280                /*
281                 * Since we have been using this adapter, it is save to assume
282                 * that it is not failed but recoverable. The card seems to
283                 * report link-up events by self-initiated queue shutdown.
284                 * That is why we need to clear the the link-down flag
285                 * which is set again in case we have missed by a mile.
286                 */
287                zfcp_erp_adapter_reopen(
288                        adapter,
289                        ZFCP_STATUS_ADAPTER_LINK_UNPLUGGED |
290                        ZFCP_STATUS_COMMON_ERP_FAILED);
291 	}
292 	return retval;
293 }
294 
295 /*
296  * function:    zfcp_qdio_request_handler
297  *
298  * purpose:	is called by QDIO layer for completed SBALs in request queue
299  *
300  * returns:	(void)
301  */
302 static void
303 zfcp_qdio_request_handler(struct ccw_device *ccw_device,
304 			  unsigned int status,
305 			  unsigned int qdio_error,
306 			  unsigned int siga_error,
307 			  unsigned int queue_number,
308 			  int first_element,
309 			  int elements_processed,
310 			  unsigned long int_parm)
311 {
312 	struct zfcp_adapter *adapter;
313 	struct zfcp_qdio_queue *queue;
314 
315 	adapter = (struct zfcp_adapter *) int_parm;
316 	queue = &adapter->request_queue;
317 
318 	ZFCP_LOG_DEBUG("adapter %s, first=%d, elements_processed=%d\n",
319 		       zfcp_get_busid_by_adapter(adapter),
320 		       first_element, elements_processed);
321 
322 	if (unlikely(zfcp_qdio_handler_error_check(adapter, status, qdio_error,
323 					           siga_error)))
324 		goto out;
325 	/*
326 	 * we stored address of struct zfcp_adapter  data structure
327 	 * associated with irq in int_parm
328 	 */
329 
330 	/* cleanup all SBALs being program-owned now */
331 	zfcp_qdio_zero_sbals(queue->buffer, first_element, elements_processed);
332 
333 	/* increase free space in outbound queue */
334 	atomic_add(elements_processed, &queue->free_count);
335 	ZFCP_LOG_DEBUG("free_count=%d\n", atomic_read(&queue->free_count));
336 	wake_up(&adapter->request_wq);
337 	ZFCP_LOG_DEBUG("elements_processed=%d, free count=%d\n",
338 		       elements_processed, atomic_read(&queue->free_count));
339  out:
340 	return;
341 }
342 
343 /*
344  * function:   	zfcp_qdio_response_handler
345  *
346  * purpose:	is called by QDIO layer for completed SBALs in response queue
347  *
348  * returns:	(void)
349  */
350 static void
351 zfcp_qdio_response_handler(struct ccw_device *ccw_device,
352 			   unsigned int status,
353 			   unsigned int qdio_error,
354 			   unsigned int siga_error,
355 			   unsigned int queue_number,
356 			   int first_element,
357 			   int elements_processed,
358 			   unsigned long int_parm)
359 {
360 	struct zfcp_adapter *adapter;
361 	struct zfcp_qdio_queue *queue;
362 	int buffer_index;
363 	int i;
364 	struct qdio_buffer *buffer;
365 	int retval = 0;
366 	u8 count;
367 	u8 start;
368 	volatile struct qdio_buffer_element *buffere = NULL;
369 	int buffere_index;
370 
371 	adapter = (struct zfcp_adapter *) int_parm;
372 	queue = &adapter->response_queue;
373 
374 	if (unlikely(zfcp_qdio_handler_error_check(adapter, status, qdio_error,
375 					           siga_error)))
376 		goto out;
377 
378 	/*
379 	 * we stored address of struct zfcp_adapter  data structure
380 	 * associated with irq in int_parm
381 	 */
382 
383 	buffere = &(queue->buffer[first_element]->element[0]);
384 	ZFCP_LOG_DEBUG("first BUFFERE flags=0x%x\n", buffere->flags);
385 	/*
386 	 * go through all SBALs from input queue currently
387 	 * returned by QDIO layer
388 	 */
389 
390 	for (i = 0; i < elements_processed; i++) {
391 
392 		buffer_index = first_element + i;
393 		buffer_index %= QDIO_MAX_BUFFERS_PER_Q;
394 		buffer = queue->buffer[buffer_index];
395 
396 		/* go through all SBALEs of SBAL */
397 		for (buffere_index = 0;
398 		     buffere_index < QDIO_MAX_ELEMENTS_PER_BUFFER;
399 		     buffere_index++) {
400 
401 			/* look for QDIO request identifiers in SB */
402 			buffere = &buffer->element[buffere_index];
403 			retval = zfcp_qdio_reqid_check(adapter,
404 						       (void *) buffere->addr);
405 
406 			if (retval) {
407 				ZFCP_LOG_NORMAL("bug: unexpected inbound "
408 						"packet on adapter %s "
409 						"(reqid=0x%lx, "
410 						"first_element=%d, "
411 						"elements_processed=%d)\n",
412 						zfcp_get_busid_by_adapter(adapter),
413 						(unsigned long) buffere->addr,
414 						first_element,
415 						elements_processed);
416 				ZFCP_LOG_NORMAL("hex dump of inbound buffer "
417 						"at address %p "
418 						"(buffer_index=%d, "
419 						"buffere_index=%d)\n", buffer,
420 						buffer_index, buffere_index);
421 				ZFCP_HEX_DUMP(ZFCP_LOG_LEVEL_NORMAL,
422 					      (char *) buffer, SBAL_SIZE);
423 			}
424 			/*
425 			 * A single used SBALE per inbound SBALE has been
426 			 * implemented by QDIO so far. Hope they will
427 			 * do some optimisation. Will need to change to
428 			 * unlikely() then.
429 			 */
430 			if (likely(buffere->flags & SBAL_FLAGS_LAST_ENTRY))
431 				break;
432 		};
433 
434 		if (unlikely(!(buffere->flags & SBAL_FLAGS_LAST_ENTRY))) {
435 			ZFCP_LOG_NORMAL("bug: End of inbound data "
436 					"not marked!\n");
437 		}
438 	}
439 
440 	/*
441 	 * put range of SBALs back to response queue
442 	 * (including SBALs which have already been free before)
443 	 */
444 	count = atomic_read(&queue->free_count) + elements_processed;
445 	start = queue->free_index;
446 
447 	ZFCP_LOG_TRACE("calling do_QDIO on adapter %s (flags=0x%x, "
448 		       "queue_no=%i, index_in_queue=%i, count=%i, "
449 		       "buffers=0x%lx\n",
450 		       zfcp_get_busid_by_adapter(adapter),
451 		       QDIO_FLAG_SYNC_INPUT | QDIO_FLAG_UNDER_INTERRUPT,
452 		       0, start, count, (unsigned long) &queue->buffer[start]);
453 
454 	retval = do_QDIO(ccw_device,
455 			 QDIO_FLAG_SYNC_INPUT | QDIO_FLAG_UNDER_INTERRUPT,
456 			 0, start, count, NULL);
457 
458 	if (unlikely(retval)) {
459 		atomic_set(&queue->free_count, count);
460 		ZFCP_LOG_DEBUG("clearing of inbound data regions failed, "
461 			       "queues may be down "
462 			       "(count=%d, start=%d, retval=%d)\n",
463 			       count, start, retval);
464 	} else {
465 		queue->free_index += count;
466 		queue->free_index %= QDIO_MAX_BUFFERS_PER_Q;
467 		atomic_set(&queue->free_count, 0);
468 		ZFCP_LOG_TRACE("%i buffers enqueued to response "
469 			       "queue at position %i\n", count, start);
470 	}
471  out:
472 	return;
473 }
474 
475 /*
476  * function:	zfcp_qdio_reqid_check
477  *
478  * purpose:	checks for valid reqids or unsolicited status
479  *
480  * returns:	0 - valid request id or unsolicited status
481  *		!0 - otherwise
482  */
483 int
484 zfcp_qdio_reqid_check(struct zfcp_adapter *adapter, void *sbale_addr)
485 {
486 	struct zfcp_fsf_req *fsf_req;
487 	int retval = 0;
488 
489 	/* invalid (per convention used in this driver) */
490 	if (unlikely(!sbale_addr)) {
491 		ZFCP_LOG_NORMAL("bug: invalid reqid\n");
492 		retval = -EINVAL;
493 		goto out;
494 	}
495 
496 	/* valid request id and thus (hopefully :) valid fsf_req address */
497 	fsf_req = (struct zfcp_fsf_req *) sbale_addr;
498 
499 	if (unlikely(adapter != fsf_req->adapter)) {
500 		ZFCP_LOG_NORMAL("bug: invalid reqid (fsf_req=%p, "
501 				"fsf_req->adapter=%p, adapter=%p)\n",
502 				fsf_req, fsf_req->adapter, adapter);
503 		retval = -EINVAL;
504 		goto out;
505 	}
506 
507 	ZFCP_LOG_TRACE("fsf_req at %p, QTCB at %p\n", fsf_req, fsf_req->qtcb);
508 	if (likely(fsf_req->qtcb)) {
509 		ZFCP_LOG_TRACE("hex dump of QTCB:\n");
510 		ZFCP_HEX_DUMP(ZFCP_LOG_LEVEL_TRACE, (char *) fsf_req->qtcb,
511 			      sizeof(struct fsf_qtcb));
512 	}
513 
514 	/* finish the FSF request */
515 	zfcp_fsf_req_complete(fsf_req);
516  out:
517 	return retval;
518 }
519 
520 /**
521  * zfcp_qdio_sbale_get - return pointer to SBALE of qdio_queue
522  * @queue: queue from which SBALE should be returned
523  * @sbal: specifies number of SBAL in queue
524  * @sbale: specifes number of SBALE in SBAL
525  */
526 static inline volatile struct qdio_buffer_element *
527 zfcp_qdio_sbale_get(struct zfcp_qdio_queue *queue, int sbal, int sbale)
528 {
529 	return &queue->buffer[sbal]->element[sbale];
530 }
531 
532 /**
533  * zfcp_qdio_sbale_req - return pointer to SBALE of request_queue for
534  *	a struct zfcp_fsf_req
535  */
536 inline volatile struct qdio_buffer_element *
537 zfcp_qdio_sbale_req(struct zfcp_fsf_req *fsf_req, int sbal, int sbale)
538 {
539 	return zfcp_qdio_sbale_get(&fsf_req->adapter->request_queue,
540 				   sbal, sbale);
541 }
542 
543 /**
544  * zfcp_qdio_sbale_resp - return pointer to SBALE of response_queue for
545  *	a struct zfcp_fsf_req
546  */
547 static inline volatile struct qdio_buffer_element *
548 zfcp_qdio_sbale_resp(struct zfcp_fsf_req *fsf_req, int sbal, int sbale)
549 {
550 	return zfcp_qdio_sbale_get(&fsf_req->adapter->response_queue,
551 				   sbal, sbale);
552 }
553 
554 /**
555  * zfcp_qdio_sbale_curr - return current SBALE on request_queue for
556  *	a struct zfcp_fsf_req
557  */
558 inline volatile struct qdio_buffer_element *
559 zfcp_qdio_sbale_curr(struct zfcp_fsf_req *fsf_req)
560 {
561 	return zfcp_qdio_sbale_req(fsf_req, fsf_req->sbal_curr,
562 				   fsf_req->sbale_curr);
563 }
564 
565 /**
566  * zfcp_qdio_sbal_limit - determine maximum number of SBALs that can be used
567  *	on the request_queue for a struct zfcp_fsf_req
568  * @fsf_req: the number of the last SBAL that can be used is stored herein
569  * @max_sbals: used to pass an upper limit for the number of SBALs
570  *
571  * Note: We can assume at least one free SBAL in the request_queue when called.
572  */
573 static inline void
574 zfcp_qdio_sbal_limit(struct zfcp_fsf_req *fsf_req, int max_sbals)
575 {
576 	int count = atomic_read(&fsf_req->adapter->request_queue.free_count);
577 	count = min(count, max_sbals);
578 	fsf_req->sbal_last  = fsf_req->sbal_first;
579 	fsf_req->sbal_last += (count - 1);
580 	fsf_req->sbal_last %= QDIO_MAX_BUFFERS_PER_Q;
581 }
582 
583 /**
584  * zfcp_qdio_sbal_chain - chain SBALs if more than one SBAL is needed for a
585  *	request
586  * @fsf_req: zfcp_fsf_req to be processed
587  * @sbtype: SBAL flags which have to be set in first SBALE of new SBAL
588  *
589  * This function changes sbal_curr, sbale_curr, sbal_number of fsf_req.
590  */
591 static inline volatile struct qdio_buffer_element *
592 zfcp_qdio_sbal_chain(struct zfcp_fsf_req *fsf_req, unsigned long sbtype)
593 {
594 	volatile struct qdio_buffer_element *sbale;
595 
596 	/* set last entry flag in current SBALE of current SBAL */
597 	sbale = zfcp_qdio_sbale_curr(fsf_req);
598 	sbale->flags |= SBAL_FLAGS_LAST_ENTRY;
599 
600 	/* don't exceed last allowed SBAL */
601 	if (fsf_req->sbal_curr == fsf_req->sbal_last)
602 		return NULL;
603 
604 	/* set chaining flag in first SBALE of current SBAL */
605 	sbale = zfcp_qdio_sbale_req(fsf_req, fsf_req->sbal_curr, 0);
606 	sbale->flags |= SBAL_FLAGS0_MORE_SBALS;
607 
608 	/* calculate index of next SBAL */
609 	fsf_req->sbal_curr++;
610 	fsf_req->sbal_curr %= QDIO_MAX_BUFFERS_PER_Q;
611 
612 	/* keep this requests number of SBALs up-to-date */
613 	fsf_req->sbal_number++;
614 
615 	/* start at first SBALE of new SBAL */
616 	fsf_req->sbale_curr = 0;
617 
618 	/* set storage-block type for new SBAL */
619 	sbale = zfcp_qdio_sbale_curr(fsf_req);
620 	sbale->flags |= sbtype;
621 
622 	return sbale;
623 }
624 
625 /**
626  * zfcp_qdio_sbale_next - switch to next SBALE, chain SBALs if needed
627  */
628 static inline volatile struct qdio_buffer_element *
629 zfcp_qdio_sbale_next(struct zfcp_fsf_req *fsf_req, unsigned long sbtype)
630 {
631 	if (fsf_req->sbale_curr == ZFCP_LAST_SBALE_PER_SBAL)
632 		return zfcp_qdio_sbal_chain(fsf_req, sbtype);
633 
634 	fsf_req->sbale_curr++;
635 
636 	return zfcp_qdio_sbale_curr(fsf_req);
637 }
638 
639 /**
640  * zfcp_qdio_sbals_zero - initialize SBALs between first and last in queue
641  *	with zero from
642  */
643 static inline int
644 zfcp_qdio_sbals_zero(struct zfcp_qdio_queue *queue, int first, int last)
645 {
646 	struct qdio_buffer **buf = queue->buffer;
647 	int curr = first;
648 	int count = 0;
649 
650 	for(;;) {
651 		curr %= QDIO_MAX_BUFFERS_PER_Q;
652 		count++;
653 		memset(buf[curr], 0, sizeof(struct qdio_buffer));
654 		if (curr == last)
655 			break;
656 		curr++;
657 	}
658 	return count;
659 }
660 
661 
662 /**
663  * zfcp_qdio_sbals_wipe - reset all changes in SBALs for an fsf_req
664  */
665 static inline int
666 zfcp_qdio_sbals_wipe(struct zfcp_fsf_req *fsf_req)
667 {
668 	return zfcp_qdio_sbals_zero(&fsf_req->adapter->request_queue,
669 				    fsf_req->sbal_first, fsf_req->sbal_curr);
670 }
671 
672 
673 /**
674  * zfcp_qdio_sbale_fill - set address and lenght in current SBALE
675  *	on request_queue
676  */
677 static inline void
678 zfcp_qdio_sbale_fill(struct zfcp_fsf_req *fsf_req, unsigned long sbtype,
679 		     void *addr, int length)
680 {
681 	volatile struct qdio_buffer_element *sbale;
682 
683 	sbale = zfcp_qdio_sbale_curr(fsf_req);
684 	sbale->addr = addr;
685 	sbale->length = length;
686 }
687 
688 /**
689  * zfcp_qdio_sbals_from_segment - map memory segment to SBALE(s)
690  * @fsf_req: request to be processed
691  * @sbtype: SBALE flags
692  * @start_addr: address of memory segment
693  * @total_length: length of memory segment
694  *
695  * Alignment and length of the segment determine how many SBALEs are needed
696  * for the memory segment.
697  */
698 static inline int
699 zfcp_qdio_sbals_from_segment(struct zfcp_fsf_req *fsf_req, unsigned long sbtype,
700 			     void *start_addr, unsigned long total_length)
701 {
702 	unsigned long remaining, length;
703 	void *addr;
704 
705 	/* split segment up heeding page boundaries */
706 	for (addr = start_addr, remaining = total_length; remaining > 0;
707 	     addr += length, remaining -= length) {
708 		/* get next free SBALE for new piece */
709 		if (NULL == zfcp_qdio_sbale_next(fsf_req, sbtype)) {
710 			/* no SBALE left, clean up and leave */
711 			zfcp_qdio_sbals_wipe(fsf_req);
712 			return -EINVAL;
713 		}
714 		/* calculate length of new piece */
715 		length = min(remaining,
716 			     (PAGE_SIZE - ((unsigned long) addr &
717 					   (PAGE_SIZE - 1))));
718 		/* fill current SBALE with calculated piece */
719 		zfcp_qdio_sbale_fill(fsf_req, sbtype, addr, length);
720 	}
721 	return total_length;
722 }
723 
724 
725 /**
726  * zfcp_qdio_sbals_from_sg - fill SBALs from scatter-gather list
727  * @fsf_req: request to be processed
728  * @sbtype: SBALE flags
729  * @sg: scatter-gather list
730  * @sg_count: number of elements in scatter-gather list
731  * @max_sbals: upper bound for number of SBALs to be used
732  */
733 inline int
734 zfcp_qdio_sbals_from_sg(struct zfcp_fsf_req *fsf_req, unsigned long sbtype,
735                         struct scatterlist *sg,	int sg_count, int max_sbals)
736 {
737 	int sg_index;
738 	struct scatterlist *sg_segment;
739 	int retval;
740 	volatile struct qdio_buffer_element *sbale;
741 	int bytes = 0;
742 
743 	/* figure out last allowed SBAL */
744 	zfcp_qdio_sbal_limit(fsf_req, max_sbals);
745 
746 	/* set storage-block type for current SBAL */
747 	sbale = zfcp_qdio_sbale_req(fsf_req, fsf_req->sbal_curr, 0);
748 	sbale->flags |= sbtype;
749 
750 	/* process all segements of scatter-gather list */
751 	for (sg_index = 0, sg_segment = sg, bytes = 0;
752 	     sg_index < sg_count;
753 	     sg_index++, sg_segment++) {
754 		retval = zfcp_qdio_sbals_from_segment(
755 				fsf_req,
756 				sbtype,
757 				zfcp_sg_to_address(sg_segment),
758 				sg_segment->length);
759 		if (retval < 0) {
760 			bytes = retval;
761 			goto out;
762 		} else
763                         bytes += retval;
764 	}
765 	/* assume that no other SBALEs are to follow in the same SBAL */
766 	sbale = zfcp_qdio_sbale_curr(fsf_req);
767 	sbale->flags |= SBAL_FLAGS_LAST_ENTRY;
768 out:
769 	return bytes;
770 }
771 
772 
773 /**
774  * zfcp_qdio_sbals_from_buffer - fill SBALs from buffer
775  * @fsf_req: request to be processed
776  * @sbtype: SBALE flags
777  * @buffer: data buffer
778  * @length: length of buffer
779  * @max_sbals: upper bound for number of SBALs to be used
780  */
781 static inline int
782 zfcp_qdio_sbals_from_buffer(struct zfcp_fsf_req *fsf_req, unsigned long sbtype,
783 			    void *buffer, unsigned long length, int max_sbals)
784 {
785 	struct scatterlist sg_segment;
786 
787 	zfcp_address_to_sg(buffer, &sg_segment);
788 	sg_segment.length = length;
789 
790 	return zfcp_qdio_sbals_from_sg(fsf_req, sbtype, &sg_segment, 1,
791                                        max_sbals);
792 }
793 
794 
795 /**
796  * zfcp_qdio_sbals_from_scsicmnd - fill SBALs from scsi command
797  * @fsf_req: request to be processed
798  * @sbtype: SBALE flags
799  * @scsi_cmnd: either scatter-gather list or buffer contained herein is used
800  *	to fill SBALs
801  */
802 inline int
803 zfcp_qdio_sbals_from_scsicmnd(struct zfcp_fsf_req *fsf_req,
804 			      unsigned long sbtype, struct scsi_cmnd *scsi_cmnd)
805 {
806 	if (scsi_cmnd->use_sg) {
807 		return zfcp_qdio_sbals_from_sg(fsf_req,	sbtype,
808                                                (struct scatterlist *)
809                                                scsi_cmnd->request_buffer,
810                                                scsi_cmnd->use_sg,
811                                                ZFCP_MAX_SBALS_PER_REQ);
812 	} else {
813                 return zfcp_qdio_sbals_from_buffer(fsf_req, sbtype,
814                                                    scsi_cmnd->request_buffer,
815                                                    scsi_cmnd->request_bufflen,
816                                                    ZFCP_MAX_SBALS_PER_REQ);
817 	}
818 }
819 
820 /**
821  * zfcp_qdio_determine_pci - set PCI flag in first SBALE on qdio queue if needed
822  */
823 int
824 zfcp_qdio_determine_pci(struct zfcp_qdio_queue *req_queue,
825 			struct zfcp_fsf_req *fsf_req)
826 {
827 	int new_distance_from_int;
828 	int pci_pos;
829 	volatile struct qdio_buffer_element *sbale;
830 
831 	new_distance_from_int = req_queue->distance_from_int +
832                 fsf_req->sbal_number;
833 
834 	if (unlikely(new_distance_from_int >= ZFCP_QDIO_PCI_INTERVAL)) {
835 		new_distance_from_int %= ZFCP_QDIO_PCI_INTERVAL;
836                 pci_pos  = fsf_req->sbal_first;
837 		pci_pos += fsf_req->sbal_number;
838 		pci_pos -= new_distance_from_int;
839 		pci_pos -= 1;
840 		pci_pos %= QDIO_MAX_BUFFERS_PER_Q;
841 		sbale = zfcp_qdio_sbale_req(fsf_req, pci_pos, 0);
842 		sbale->flags |= SBAL_FLAGS0_PCI;
843 	}
844 	return new_distance_from_int;
845 }
846 
847 /*
848  * function:	zfcp_zero_sbals
849  *
850  * purpose:	zeros specified range of SBALs
851  *
852  * returns:
853  */
854 void
855 zfcp_qdio_zero_sbals(struct qdio_buffer *buf[], int first, int clean_count)
856 {
857 	int cur_pos;
858 	int index;
859 
860 	for (cur_pos = first; cur_pos < (first + clean_count); cur_pos++) {
861 		index = cur_pos % QDIO_MAX_BUFFERS_PER_Q;
862 		memset(buf[index], 0, sizeof (struct qdio_buffer));
863 		ZFCP_LOG_TRACE("zeroing BUFFER %d at address %p\n",
864 			       index, buf[index]);
865 	}
866 }
867 
868 #undef ZFCP_LOG_AREA
869