1 /*
2  * Copyright (c) 2005 Cisco Systems. All rights reserved.
3  *
4  * This software is available to you under a choice of one of two
5  * licenses.  You may choose to be licensed under the terms of the GNU
6  * General Public License (GPL) Version 2, available from the file
7  * COPYING in the main directory of this source tree, or the
8  * OpenIB.org BSD license below:
9  *
10  *     Redistribution and use in source and binary forms, with or
11  *     without modification, are permitted provided that the following
12  *     conditions are met:
13  *
14  *      - Redistributions of source code must retain the above
15  *        copyright notice, this list of conditions and the following
16  *        disclaimer.
17  *
18  *      - Redistributions in binary form must reproduce the above
19  *        copyright notice, this list of conditions and the following
20  *        disclaimer in the documentation and/or other materials
21  *        provided with the distribution.
22  *
23  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
24  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
25  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
26  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
27  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
28  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
29  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
30  * SOFTWARE.
31  */
32 
33 #include <linux/slab.h>
34 #include <linux/string.h>
35 #include <linux/sched.h>
36 
37 #include <asm/io.h>
38 
39 #include "mthca_dev.h"
40 #include "mthca_cmd.h"
41 #include "mthca_memfree.h"
42 #include "mthca_wqe.h"
43 
44 enum {
45 	MTHCA_MAX_DIRECT_SRQ_SIZE = 4 * PAGE_SIZE
46 };
47 
48 struct mthca_tavor_srq_context {
49 	__be64 wqe_base_ds;	/* low 6 bits is descriptor size */
50 	__be32 state_pd;
51 	__be32 lkey;
52 	__be32 uar;
53 	__be16 limit_watermark;
54 	__be16 wqe_cnt;
55 	u32    reserved[2];
56 };
57 
58 struct mthca_arbel_srq_context {
59 	__be32 state_logsize_srqn;
60 	__be32 lkey;
61 	__be32 db_index;
62 	__be32 logstride_usrpage;
63 	__be64 wqe_base;
64 	__be32 eq_pd;
65 	__be16 limit_watermark;
66 	__be16 wqe_cnt;
67 	u16    reserved1;
68 	__be16 wqe_counter;
69 	u32    reserved2[3];
70 };
71 
72 static void *get_wqe(struct mthca_srq *srq, int n)
73 {
74 	if (srq->is_direct)
75 		return srq->queue.direct.buf + (n << srq->wqe_shift);
76 	else
77 		return srq->queue.page_list[(n << srq->wqe_shift) >> PAGE_SHIFT].buf +
78 			((n << srq->wqe_shift) & (PAGE_SIZE - 1));
79 }
80 
81 /*
82  * Return a pointer to the location within a WQE that we're using as a
83  * link when the WQE is in the free list.  We use the imm field
84  * because in the Tavor case, posting a WQE may overwrite the next
85  * segment of the previous WQE, but a receive WQE will never touch the
86  * imm field.  This avoids corrupting our free list if the previous
87  * WQE has already completed and been put on the free list when we
88  * post the next WQE.
89  */
90 static inline int *wqe_to_link(void *wqe)
91 {
92 	return (int *) (wqe + offsetof(struct mthca_next_seg, imm));
93 }
94 
95 static void mthca_tavor_init_srq_context(struct mthca_dev *dev,
96 					 struct mthca_pd *pd,
97 					 struct mthca_srq *srq,
98 					 struct mthca_tavor_srq_context *context)
99 {
100 	memset(context, 0, sizeof *context);
101 
102 	context->wqe_base_ds = cpu_to_be64(1 << (srq->wqe_shift - 4));
103 	context->state_pd    = cpu_to_be32(pd->pd_num);
104 	context->lkey        = cpu_to_be32(srq->mr.ibmr.lkey);
105 
106 	if (pd->ibpd.uobject)
107 		context->uar =
108 			cpu_to_be32(to_mucontext(pd->ibpd.uobject->context)->uar.index);
109 	else
110 		context->uar = cpu_to_be32(dev->driver_uar.index);
111 }
112 
113 static void mthca_arbel_init_srq_context(struct mthca_dev *dev,
114 					 struct mthca_pd *pd,
115 					 struct mthca_srq *srq,
116 					 struct mthca_arbel_srq_context *context)
117 {
118 	int logsize, max;
119 
120 	memset(context, 0, sizeof *context);
121 
122 	/*
123 	 * Put max in a temporary variable to work around gcc bug
124 	 * triggered by ilog2() on sparc64.
125 	 */
126 	max = srq->max;
127 	logsize = ilog2(max);
128 	context->state_logsize_srqn = cpu_to_be32(logsize << 24 | srq->srqn);
129 	context->lkey = cpu_to_be32(srq->mr.ibmr.lkey);
130 	context->db_index = cpu_to_be32(srq->db_index);
131 	context->logstride_usrpage = cpu_to_be32((srq->wqe_shift - 4) << 29);
132 	if (pd->ibpd.uobject)
133 		context->logstride_usrpage |=
134 			cpu_to_be32(to_mucontext(pd->ibpd.uobject->context)->uar.index);
135 	else
136 		context->logstride_usrpage |= cpu_to_be32(dev->driver_uar.index);
137 	context->eq_pd = cpu_to_be32(MTHCA_EQ_ASYNC << 24 | pd->pd_num);
138 }
139 
140 static void mthca_free_srq_buf(struct mthca_dev *dev, struct mthca_srq *srq)
141 {
142 	mthca_buf_free(dev, srq->max << srq->wqe_shift, &srq->queue,
143 		       srq->is_direct, &srq->mr);
144 	kfree(srq->wrid);
145 }
146 
147 static int mthca_alloc_srq_buf(struct mthca_dev *dev, struct mthca_pd *pd,
148 			       struct mthca_srq *srq)
149 {
150 	struct mthca_data_seg *scatter;
151 	void *wqe;
152 	int err;
153 	int i;
154 
155 	if (pd->ibpd.uobject)
156 		return 0;
157 
158 	srq->wrid = kmalloc(srq->max * sizeof (u64), GFP_KERNEL);
159 	if (!srq->wrid)
160 		return -ENOMEM;
161 
162 	err = mthca_buf_alloc(dev, srq->max << srq->wqe_shift,
163 			      MTHCA_MAX_DIRECT_SRQ_SIZE,
164 			      &srq->queue, &srq->is_direct, pd, 1, &srq->mr);
165 	if (err) {
166 		kfree(srq->wrid);
167 		return err;
168 	}
169 
170 	/*
171 	 * Now initialize the SRQ buffer so that all of the WQEs are
172 	 * linked into the list of free WQEs.  In addition, set the
173 	 * scatter list L_Keys to the sentry value of 0x100.
174 	 */
175 	for (i = 0; i < srq->max; ++i) {
176 		struct mthca_next_seg *next;
177 
178 		next = wqe = get_wqe(srq, i);
179 
180 		if (i < srq->max - 1) {
181 			*wqe_to_link(wqe) = i + 1;
182 			next->nda_op = htonl(((i + 1) << srq->wqe_shift) | 1);
183 		} else {
184 			*wqe_to_link(wqe) = -1;
185 			next->nda_op = 0;
186 		}
187 
188 		for (scatter = wqe + sizeof (struct mthca_next_seg);
189 		     (void *) scatter < wqe + (1 << srq->wqe_shift);
190 		     ++scatter)
191 			scatter->lkey = cpu_to_be32(MTHCA_INVAL_LKEY);
192 	}
193 
194 	srq->last = get_wqe(srq, srq->max - 1);
195 
196 	return 0;
197 }
198 
199 int mthca_alloc_srq(struct mthca_dev *dev, struct mthca_pd *pd,
200 		    struct ib_srq_attr *attr, struct mthca_srq *srq)
201 {
202 	struct mthca_mailbox *mailbox;
203 	int ds;
204 	int err;
205 
206 	/* Sanity check SRQ size before proceeding */
207 	if (attr->max_wr  > dev->limits.max_srq_wqes ||
208 	    attr->max_sge > dev->limits.max_srq_sge)
209 		return -EINVAL;
210 
211 	srq->max      = attr->max_wr;
212 	srq->max_gs   = attr->max_sge;
213 	srq->counter  = 0;
214 
215 	if (mthca_is_memfree(dev))
216 		srq->max = roundup_pow_of_two(srq->max + 1);
217 	else
218 		srq->max = srq->max + 1;
219 
220 	ds = max(64UL,
221 		 roundup_pow_of_two(sizeof (struct mthca_next_seg) +
222 				    srq->max_gs * sizeof (struct mthca_data_seg)));
223 
224 	if (!mthca_is_memfree(dev) && (ds > dev->limits.max_desc_sz))
225 		return -EINVAL;
226 
227 	srq->wqe_shift = ilog2(ds);
228 
229 	srq->srqn = mthca_alloc(&dev->srq_table.alloc);
230 	if (srq->srqn == -1)
231 		return -ENOMEM;
232 
233 	if (mthca_is_memfree(dev)) {
234 		err = mthca_table_get(dev, dev->srq_table.table, srq->srqn);
235 		if (err)
236 			goto err_out;
237 
238 		if (!pd->ibpd.uobject) {
239 			srq->db_index = mthca_alloc_db(dev, MTHCA_DB_TYPE_SRQ,
240 						       srq->srqn, &srq->db);
241 			if (srq->db_index < 0) {
242 				err = -ENOMEM;
243 				goto err_out_icm;
244 			}
245 		}
246 	}
247 
248 	mailbox = mthca_alloc_mailbox(dev, GFP_KERNEL);
249 	if (IS_ERR(mailbox)) {
250 		err = PTR_ERR(mailbox);
251 		goto err_out_db;
252 	}
253 
254 	err = mthca_alloc_srq_buf(dev, pd, srq);
255 	if (err)
256 		goto err_out_mailbox;
257 
258 	spin_lock_init(&srq->lock);
259 	srq->refcount = 1;
260 	init_waitqueue_head(&srq->wait);
261 	mutex_init(&srq->mutex);
262 
263 	if (mthca_is_memfree(dev))
264 		mthca_arbel_init_srq_context(dev, pd, srq, mailbox->buf);
265 	else
266 		mthca_tavor_init_srq_context(dev, pd, srq, mailbox->buf);
267 
268 	err = mthca_SW2HW_SRQ(dev, mailbox, srq->srqn);
269 
270 	if (err) {
271 		mthca_warn(dev, "SW2HW_SRQ failed (%d)\n", err);
272 		goto err_out_free_buf;
273 	}
274 
275 	spin_lock_irq(&dev->srq_table.lock);
276 	if (mthca_array_set(&dev->srq_table.srq,
277 			    srq->srqn & (dev->limits.num_srqs - 1),
278 			    srq)) {
279 		spin_unlock_irq(&dev->srq_table.lock);
280 		goto err_out_free_srq;
281 	}
282 	spin_unlock_irq(&dev->srq_table.lock);
283 
284 	mthca_free_mailbox(dev, mailbox);
285 
286 	srq->first_free = 0;
287 	srq->last_free  = srq->max - 1;
288 
289 	attr->max_wr    = srq->max - 1;
290 	attr->max_sge   = srq->max_gs;
291 
292 	return 0;
293 
294 err_out_free_srq:
295 	err = mthca_HW2SW_SRQ(dev, mailbox, srq->srqn);
296 	if (err)
297 		mthca_warn(dev, "HW2SW_SRQ failed (%d)\n", err);
298 
299 err_out_free_buf:
300 	if (!pd->ibpd.uobject)
301 		mthca_free_srq_buf(dev, srq);
302 
303 err_out_mailbox:
304 	mthca_free_mailbox(dev, mailbox);
305 
306 err_out_db:
307 	if (!pd->ibpd.uobject && mthca_is_memfree(dev))
308 		mthca_free_db(dev, MTHCA_DB_TYPE_SRQ, srq->db_index);
309 
310 err_out_icm:
311 	mthca_table_put(dev, dev->srq_table.table, srq->srqn);
312 
313 err_out:
314 	mthca_free(&dev->srq_table.alloc, srq->srqn);
315 
316 	return err;
317 }
318 
319 static inline int get_srq_refcount(struct mthca_dev *dev, struct mthca_srq *srq)
320 {
321 	int c;
322 
323 	spin_lock_irq(&dev->srq_table.lock);
324 	c = srq->refcount;
325 	spin_unlock_irq(&dev->srq_table.lock);
326 
327 	return c;
328 }
329 
330 void mthca_free_srq(struct mthca_dev *dev, struct mthca_srq *srq)
331 {
332 	struct mthca_mailbox *mailbox;
333 	int err;
334 
335 	mailbox = mthca_alloc_mailbox(dev, GFP_KERNEL);
336 	if (IS_ERR(mailbox)) {
337 		mthca_warn(dev, "No memory for mailbox to free SRQ.\n");
338 		return;
339 	}
340 
341 	err = mthca_HW2SW_SRQ(dev, mailbox, srq->srqn);
342 	if (err)
343 		mthca_warn(dev, "HW2SW_SRQ failed (%d)\n", err);
344 
345 	spin_lock_irq(&dev->srq_table.lock);
346 	mthca_array_clear(&dev->srq_table.srq,
347 			  srq->srqn & (dev->limits.num_srqs - 1));
348 	--srq->refcount;
349 	spin_unlock_irq(&dev->srq_table.lock);
350 
351 	wait_event(srq->wait, !get_srq_refcount(dev, srq));
352 
353 	if (!srq->ibsrq.uobject) {
354 		mthca_free_srq_buf(dev, srq);
355 		if (mthca_is_memfree(dev))
356 			mthca_free_db(dev, MTHCA_DB_TYPE_SRQ, srq->db_index);
357 	}
358 
359 	mthca_table_put(dev, dev->srq_table.table, srq->srqn);
360 	mthca_free(&dev->srq_table.alloc, srq->srqn);
361 	mthca_free_mailbox(dev, mailbox);
362 }
363 
364 int mthca_modify_srq(struct ib_srq *ibsrq, struct ib_srq_attr *attr,
365 		     enum ib_srq_attr_mask attr_mask, struct ib_udata *udata)
366 {
367 	struct mthca_dev *dev = to_mdev(ibsrq->device);
368 	struct mthca_srq *srq = to_msrq(ibsrq);
369 	int ret = 0;
370 
371 	/* We don't support resizing SRQs (yet?) */
372 	if (attr_mask & IB_SRQ_MAX_WR)
373 		return -EINVAL;
374 
375 	if (attr_mask & IB_SRQ_LIMIT) {
376 		u32 max_wr = mthca_is_memfree(dev) ? srq->max - 1 : srq->max;
377 		if (attr->srq_limit > max_wr)
378 			return -EINVAL;
379 
380 		mutex_lock(&srq->mutex);
381 		ret = mthca_ARM_SRQ(dev, srq->srqn, attr->srq_limit);
382 		mutex_unlock(&srq->mutex);
383 	}
384 
385 	return ret;
386 }
387 
388 int mthca_query_srq(struct ib_srq *ibsrq, struct ib_srq_attr *srq_attr)
389 {
390 	struct mthca_dev *dev = to_mdev(ibsrq->device);
391 	struct mthca_srq *srq = to_msrq(ibsrq);
392 	struct mthca_mailbox *mailbox;
393 	struct mthca_arbel_srq_context *arbel_ctx;
394 	struct mthca_tavor_srq_context *tavor_ctx;
395 	int err;
396 
397 	mailbox = mthca_alloc_mailbox(dev, GFP_KERNEL);
398 	if (IS_ERR(mailbox))
399 		return PTR_ERR(mailbox);
400 
401 	err = mthca_QUERY_SRQ(dev, srq->srqn, mailbox);
402 	if (err)
403 		goto out;
404 
405 	if (mthca_is_memfree(dev)) {
406 		arbel_ctx = mailbox->buf;
407 		srq_attr->srq_limit = be16_to_cpu(arbel_ctx->limit_watermark);
408 	} else {
409 		tavor_ctx = mailbox->buf;
410 		srq_attr->srq_limit = be16_to_cpu(tavor_ctx->limit_watermark);
411 	}
412 
413 	srq_attr->max_wr  = srq->max - 1;
414 	srq_attr->max_sge = srq->max_gs;
415 
416 out:
417 	mthca_free_mailbox(dev, mailbox);
418 
419 	return err;
420 }
421 
422 void mthca_srq_event(struct mthca_dev *dev, u32 srqn,
423 		     enum ib_event_type event_type)
424 {
425 	struct mthca_srq *srq;
426 	struct ib_event event;
427 
428 	spin_lock(&dev->srq_table.lock);
429 	srq = mthca_array_get(&dev->srq_table.srq, srqn & (dev->limits.num_srqs - 1));
430 	if (srq)
431 		++srq->refcount;
432 	spin_unlock(&dev->srq_table.lock);
433 
434 	if (!srq) {
435 		mthca_warn(dev, "Async event for bogus SRQ %08x\n", srqn);
436 		return;
437 	}
438 
439 	if (!srq->ibsrq.event_handler)
440 		goto out;
441 
442 	event.device      = &dev->ib_dev;
443 	event.event       = event_type;
444 	event.element.srq = &srq->ibsrq;
445 	srq->ibsrq.event_handler(&event, srq->ibsrq.srq_context);
446 
447 out:
448 	spin_lock(&dev->srq_table.lock);
449 	if (!--srq->refcount)
450 		wake_up(&srq->wait);
451 	spin_unlock(&dev->srq_table.lock);
452 }
453 
454 /*
455  * This function must be called with IRQs disabled.
456  */
457 void mthca_free_srq_wqe(struct mthca_srq *srq, u32 wqe_addr)
458 {
459 	int ind;
460 	struct mthca_next_seg *last_free;
461 
462 	ind = wqe_addr >> srq->wqe_shift;
463 
464 	spin_lock(&srq->lock);
465 
466 	last_free = get_wqe(srq, srq->last_free);
467 	*wqe_to_link(last_free) = ind;
468 	last_free->nda_op = htonl((ind << srq->wqe_shift) | 1);
469 	*wqe_to_link(get_wqe(srq, ind)) = -1;
470 	srq->last_free = ind;
471 
472 	spin_unlock(&srq->lock);
473 }
474 
475 int mthca_tavor_post_srq_recv(struct ib_srq *ibsrq, struct ib_recv_wr *wr,
476 			      struct ib_recv_wr **bad_wr)
477 {
478 	struct mthca_dev *dev = to_mdev(ibsrq->device);
479 	struct mthca_srq *srq = to_msrq(ibsrq);
480 	unsigned long flags;
481 	int err = 0;
482 	int first_ind;
483 	int ind;
484 	int next_ind;
485 	int nreq;
486 	int i;
487 	void *wqe;
488 	void *prev_wqe;
489 
490 	spin_lock_irqsave(&srq->lock, flags);
491 
492 	first_ind = srq->first_free;
493 
494 	for (nreq = 0; wr; wr = wr->next) {
495 		ind       = srq->first_free;
496 		wqe       = get_wqe(srq, ind);
497 		next_ind  = *wqe_to_link(wqe);
498 
499 		if (unlikely(next_ind < 0)) {
500 			mthca_err(dev, "SRQ %06x full\n", srq->srqn);
501 			err = -ENOMEM;
502 			*bad_wr = wr;
503 			break;
504 		}
505 
506 		prev_wqe  = srq->last;
507 		srq->last = wqe;
508 
509 		((struct mthca_next_seg *) wqe)->ee_nds = 0;
510 		/* flags field will always remain 0 */
511 
512 		wqe += sizeof (struct mthca_next_seg);
513 
514 		if (unlikely(wr->num_sge > srq->max_gs)) {
515 			err = -EINVAL;
516 			*bad_wr = wr;
517 			srq->last = prev_wqe;
518 			break;
519 		}
520 
521 		for (i = 0; i < wr->num_sge; ++i) {
522 			mthca_set_data_seg(wqe, wr->sg_list + i);
523 			wqe += sizeof (struct mthca_data_seg);
524 		}
525 
526 		if (i < srq->max_gs)
527 			mthca_set_data_seg_inval(wqe);
528 
529 		((struct mthca_next_seg *) prev_wqe)->ee_nds =
530 			cpu_to_be32(MTHCA_NEXT_DBD);
531 
532 		srq->wrid[ind]  = wr->wr_id;
533 		srq->first_free = next_ind;
534 
535 		++nreq;
536 		if (unlikely(nreq == MTHCA_TAVOR_MAX_WQES_PER_RECV_DB)) {
537 			nreq = 0;
538 
539 			/*
540 			 * Make sure that descriptors are written
541 			 * before doorbell is rung.
542 			 */
543 			wmb();
544 
545 			mthca_write64(first_ind << srq->wqe_shift, srq->srqn << 8,
546 				      dev->kar + MTHCA_RECEIVE_DOORBELL,
547 				      MTHCA_GET_DOORBELL_LOCK(&dev->doorbell_lock));
548 
549 			first_ind = srq->first_free;
550 		}
551 	}
552 
553 	if (likely(nreq)) {
554 		/*
555 		 * Make sure that descriptors are written before
556 		 * doorbell is rung.
557 		 */
558 		wmb();
559 
560 		mthca_write64(first_ind << srq->wqe_shift, (srq->srqn << 8) | nreq,
561 			      dev->kar + MTHCA_RECEIVE_DOORBELL,
562 			      MTHCA_GET_DOORBELL_LOCK(&dev->doorbell_lock));
563 	}
564 
565 	/*
566 	 * Make sure doorbells don't leak out of SRQ spinlock and
567 	 * reach the HCA out of order:
568 	 */
569 	mmiowb();
570 
571 	spin_unlock_irqrestore(&srq->lock, flags);
572 	return err;
573 }
574 
575 int mthca_arbel_post_srq_recv(struct ib_srq *ibsrq, struct ib_recv_wr *wr,
576 			      struct ib_recv_wr **bad_wr)
577 {
578 	struct mthca_dev *dev = to_mdev(ibsrq->device);
579 	struct mthca_srq *srq = to_msrq(ibsrq);
580 	unsigned long flags;
581 	int err = 0;
582 	int ind;
583 	int next_ind;
584 	int nreq;
585 	int i;
586 	void *wqe;
587 
588 	spin_lock_irqsave(&srq->lock, flags);
589 
590 	for (nreq = 0; wr; ++nreq, wr = wr->next) {
591 		ind       = srq->first_free;
592 		wqe       = get_wqe(srq, ind);
593 		next_ind  = *wqe_to_link(wqe);
594 
595 		if (unlikely(next_ind < 0)) {
596 			mthca_err(dev, "SRQ %06x full\n", srq->srqn);
597 			err = -ENOMEM;
598 			*bad_wr = wr;
599 			break;
600 		}
601 
602 		((struct mthca_next_seg *) wqe)->ee_nds = 0;
603 		/* flags field will always remain 0 */
604 
605 		wqe += sizeof (struct mthca_next_seg);
606 
607 		if (unlikely(wr->num_sge > srq->max_gs)) {
608 			err = -EINVAL;
609 			*bad_wr = wr;
610 			break;
611 		}
612 
613 		for (i = 0; i < wr->num_sge; ++i) {
614 			mthca_set_data_seg(wqe, wr->sg_list + i);
615 			wqe += sizeof (struct mthca_data_seg);
616 		}
617 
618 		if (i < srq->max_gs)
619 			mthca_set_data_seg_inval(wqe);
620 
621 		srq->wrid[ind]  = wr->wr_id;
622 		srq->first_free = next_ind;
623 	}
624 
625 	if (likely(nreq)) {
626 		srq->counter += nreq;
627 
628 		/*
629 		 * Make sure that descriptors are written before
630 		 * we write doorbell record.
631 		 */
632 		wmb();
633 		*srq->db = cpu_to_be32(srq->counter);
634 	}
635 
636 	spin_unlock_irqrestore(&srq->lock, flags);
637 	return err;
638 }
639 
640 int mthca_max_srq_sge(struct mthca_dev *dev)
641 {
642 	if (mthca_is_memfree(dev))
643 		return dev->limits.max_sg;
644 
645 	/*
646 	 * SRQ allocations are based on powers of 2 for Tavor,
647 	 * (although they only need to be multiples of 16 bytes).
648 	 *
649 	 * Therefore, we need to base the max number of sg entries on
650 	 * the largest power of 2 descriptor size that is <= to the
651 	 * actual max WQE descriptor size, rather than return the
652 	 * max_sg value given by the firmware (which is based on WQE
653 	 * sizes as multiples of 16, not powers of 2).
654 	 *
655 	 * If SRQ implementation is changed for Tavor to be based on
656 	 * multiples of 16, the calculation below can be deleted and
657 	 * the FW max_sg value returned.
658 	 */
659 	return min_t(int, dev->limits.max_sg,
660 		     ((1 << (fls(dev->limits.max_desc_sz) - 1)) -
661 		      sizeof (struct mthca_next_seg)) /
662 		     sizeof (struct mthca_data_seg));
663 }
664 
665 int mthca_init_srq_table(struct mthca_dev *dev)
666 {
667 	int err;
668 
669 	if (!(dev->mthca_flags & MTHCA_FLAG_SRQ))
670 		return 0;
671 
672 	spin_lock_init(&dev->srq_table.lock);
673 
674 	err = mthca_alloc_init(&dev->srq_table.alloc,
675 			       dev->limits.num_srqs,
676 			       dev->limits.num_srqs - 1,
677 			       dev->limits.reserved_srqs);
678 	if (err)
679 		return err;
680 
681 	err = mthca_array_init(&dev->srq_table.srq,
682 			       dev->limits.num_srqs);
683 	if (err)
684 		mthca_alloc_cleanup(&dev->srq_table.alloc);
685 
686 	return err;
687 }
688 
689 void mthca_cleanup_srq_table(struct mthca_dev *dev)
690 {
691 	if (!(dev->mthca_flags & MTHCA_FLAG_SRQ))
692 		return;
693 
694 	mthca_array_cleanup(&dev->srq_table.srq, dev->limits.num_srqs);
695 	mthca_alloc_cleanup(&dev->srq_table.alloc);
696 }
697