Merge branches 'release', 'acpi_pm_device_sleep_state' and 'battery' into release
[linux-2.6] / drivers / infiniband / hw / mthca / mthca_srq.c
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  * $Id: mthca_srq.c 3047 2005-08-10 03:59:35Z roland $
33  */
34
35 #include <linux/slab.h>
36 #include <linux/string.h>
37 #include <linux/sched.h>
38
39 #include <asm/io.h>
40
41 #include "mthca_dev.h"
42 #include "mthca_cmd.h"
43 #include "mthca_memfree.h"
44 #include "mthca_wqe.h"
45
46 enum {
47         MTHCA_MAX_DIRECT_SRQ_SIZE = 4 * PAGE_SIZE
48 };
49
50 struct mthca_tavor_srq_context {
51         __be64 wqe_base_ds;     /* low 6 bits is descriptor size */
52         __be32 state_pd;
53         __be32 lkey;
54         __be32 uar;
55         __be16 limit_watermark;
56         __be16 wqe_cnt;
57         u32    reserved[2];
58 };
59
60 struct mthca_arbel_srq_context {
61         __be32 state_logsize_srqn;
62         __be32 lkey;
63         __be32 db_index;
64         __be32 logstride_usrpage;
65         __be64 wqe_base;
66         __be32 eq_pd;
67         __be16 limit_watermark;
68         __be16 wqe_cnt;
69         u16    reserved1;
70         __be16 wqe_counter;
71         u32    reserved2[3];
72 };
73
74 static void *get_wqe(struct mthca_srq *srq, int n)
75 {
76         if (srq->is_direct)
77                 return srq->queue.direct.buf + (n << srq->wqe_shift);
78         else
79                 return srq->queue.page_list[(n << srq->wqe_shift) >> PAGE_SHIFT].buf +
80                         ((n << srq->wqe_shift) & (PAGE_SIZE - 1));
81 }
82
83 /*
84  * Return a pointer to the location within a WQE that we're using as a
85  * link when the WQE is in the free list.  We use the imm field
86  * because in the Tavor case, posting a WQE may overwrite the next
87  * segment of the previous WQE, but a receive WQE will never touch the
88  * imm field.  This avoids corrupting our free list if the previous
89  * WQE has already completed and been put on the free list when we
90  * post the next WQE.
91  */
92 static inline int *wqe_to_link(void *wqe)
93 {
94         return (int *) (wqe + offsetof(struct mthca_next_seg, imm));
95 }
96
97 static void mthca_tavor_init_srq_context(struct mthca_dev *dev,
98                                          struct mthca_pd *pd,
99                                          struct mthca_srq *srq,
100                                          struct mthca_tavor_srq_context *context)
101 {
102         memset(context, 0, sizeof *context);
103
104         context->wqe_base_ds = cpu_to_be64(1 << (srq->wqe_shift - 4));
105         context->state_pd    = cpu_to_be32(pd->pd_num);
106         context->lkey        = cpu_to_be32(srq->mr.ibmr.lkey);
107
108         if (pd->ibpd.uobject)
109                 context->uar =
110                         cpu_to_be32(to_mucontext(pd->ibpd.uobject->context)->uar.index);
111         else
112                 context->uar = cpu_to_be32(dev->driver_uar.index);
113 }
114
115 static void mthca_arbel_init_srq_context(struct mthca_dev *dev,
116                                          struct mthca_pd *pd,
117                                          struct mthca_srq *srq,
118                                          struct mthca_arbel_srq_context *context)
119 {
120         int logsize, max;
121
122         memset(context, 0, sizeof *context);
123
124         /*
125          * Put max in a temporary variable to work around gcc bug
126          * triggered by ilog2() on sparc64.
127          */
128         max = srq->max;
129         logsize = ilog2(max);
130         context->state_logsize_srqn = cpu_to_be32(logsize << 24 | srq->srqn);
131         context->lkey = cpu_to_be32(srq->mr.ibmr.lkey);
132         context->db_index = cpu_to_be32(srq->db_index);
133         context->logstride_usrpage = cpu_to_be32((srq->wqe_shift - 4) << 29);
134         if (pd->ibpd.uobject)
135                 context->logstride_usrpage |=
136                         cpu_to_be32(to_mucontext(pd->ibpd.uobject->context)->uar.index);
137         else
138                 context->logstride_usrpage |= cpu_to_be32(dev->driver_uar.index);
139         context->eq_pd = cpu_to_be32(MTHCA_EQ_ASYNC << 24 | pd->pd_num);
140 }
141
142 static void mthca_free_srq_buf(struct mthca_dev *dev, struct mthca_srq *srq)
143 {
144         mthca_buf_free(dev, srq->max << srq->wqe_shift, &srq->queue,
145                        srq->is_direct, &srq->mr);
146         kfree(srq->wrid);
147 }
148
149 static int mthca_alloc_srq_buf(struct mthca_dev *dev, struct mthca_pd *pd,
150                                struct mthca_srq *srq)
151 {
152         struct mthca_data_seg *scatter;
153         void *wqe;
154         int err;
155         int i;
156
157         if (pd->ibpd.uobject)
158                 return 0;
159
160         srq->wrid = kmalloc(srq->max * sizeof (u64), GFP_KERNEL);
161         if (!srq->wrid)
162                 return -ENOMEM;
163
164         err = mthca_buf_alloc(dev, srq->max << srq->wqe_shift,
165                               MTHCA_MAX_DIRECT_SRQ_SIZE,
166                               &srq->queue, &srq->is_direct, pd, 1, &srq->mr);
167         if (err) {
168                 kfree(srq->wrid);
169                 return err;
170         }
171
172         /*
173          * Now initialize the SRQ buffer so that all of the WQEs are
174          * linked into the list of free WQEs.  In addition, set the
175          * scatter list L_Keys to the sentry value of 0x100.
176          */
177         for (i = 0; i < srq->max; ++i) {
178                 struct mthca_next_seg *next;
179
180                 next = wqe = get_wqe(srq, i);
181
182                 if (i < srq->max - 1) {
183                         *wqe_to_link(wqe) = i + 1;
184                         next->nda_op = htonl(((i + 1) << srq->wqe_shift) | 1);
185                 } else {
186                         *wqe_to_link(wqe) = -1;
187                         next->nda_op = 0;
188                 }
189
190                 for (scatter = wqe + sizeof (struct mthca_next_seg);
191                      (void *) scatter < wqe + (1 << srq->wqe_shift);
192                      ++scatter)
193                         scatter->lkey = cpu_to_be32(MTHCA_INVAL_LKEY);
194         }
195
196         srq->last = get_wqe(srq, srq->max - 1);
197
198         return 0;
199 }
200
201 int mthca_alloc_srq(struct mthca_dev *dev, struct mthca_pd *pd,
202                     struct ib_srq_attr *attr, struct mthca_srq *srq)
203 {
204         struct mthca_mailbox *mailbox;
205         u8 status;
206         int ds;
207         int err;
208
209         /* Sanity check SRQ size before proceeding */
210         if (attr->max_wr  > dev->limits.max_srq_wqes ||
211             attr->max_sge > dev->limits.max_srq_sge)
212                 return -EINVAL;
213
214         srq->max      = attr->max_wr;
215         srq->max_gs   = attr->max_sge;
216         srq->counter  = 0;
217
218         if (mthca_is_memfree(dev))
219                 srq->max = roundup_pow_of_two(srq->max + 1);
220         else
221                 srq->max = srq->max + 1;
222
223         ds = max(64UL,
224                  roundup_pow_of_two(sizeof (struct mthca_next_seg) +
225                                     srq->max_gs * sizeof (struct mthca_data_seg)));
226
227         if (!mthca_is_memfree(dev) && (ds > dev->limits.max_desc_sz))
228                 return -EINVAL;
229
230         srq->wqe_shift = ilog2(ds);
231
232         srq->srqn = mthca_alloc(&dev->srq_table.alloc);
233         if (srq->srqn == -1)
234                 return -ENOMEM;
235
236         if (mthca_is_memfree(dev)) {
237                 err = mthca_table_get(dev, dev->srq_table.table, srq->srqn);
238                 if (err)
239                         goto err_out;
240
241                 if (!pd->ibpd.uobject) {
242                         srq->db_index = mthca_alloc_db(dev, MTHCA_DB_TYPE_SRQ,
243                                                        srq->srqn, &srq->db);
244                         if (srq->db_index < 0) {
245                                 err = -ENOMEM;
246                                 goto err_out_icm;
247                         }
248                 }
249         }
250
251         mailbox = mthca_alloc_mailbox(dev, GFP_KERNEL);
252         if (IS_ERR(mailbox)) {
253                 err = PTR_ERR(mailbox);
254                 goto err_out_db;
255         }
256
257         err = mthca_alloc_srq_buf(dev, pd, srq);
258         if (err)
259                 goto err_out_mailbox;
260
261         spin_lock_init(&srq->lock);
262         srq->refcount = 1;
263         init_waitqueue_head(&srq->wait);
264         mutex_init(&srq->mutex);
265
266         if (mthca_is_memfree(dev))
267                 mthca_arbel_init_srq_context(dev, pd, srq, mailbox->buf);
268         else
269                 mthca_tavor_init_srq_context(dev, pd, srq, mailbox->buf);
270
271         err = mthca_SW2HW_SRQ(dev, mailbox, srq->srqn, &status);
272
273         if (err) {
274                 mthca_warn(dev, "SW2HW_SRQ failed (%d)\n", err);
275                 goto err_out_free_buf;
276         }
277         if (status) {
278                 mthca_warn(dev, "SW2HW_SRQ returned status 0x%02x\n",
279                            status);
280                 err = -EINVAL;
281                 goto err_out_free_buf;
282         }
283
284         spin_lock_irq(&dev->srq_table.lock);
285         if (mthca_array_set(&dev->srq_table.srq,
286                             srq->srqn & (dev->limits.num_srqs - 1),
287                             srq)) {
288                 spin_unlock_irq(&dev->srq_table.lock);
289                 goto err_out_free_srq;
290         }
291         spin_unlock_irq(&dev->srq_table.lock);
292
293         mthca_free_mailbox(dev, mailbox);
294
295         srq->first_free = 0;
296         srq->last_free  = srq->max - 1;
297
298         attr->max_wr    = srq->max - 1;
299         attr->max_sge   = srq->max_gs;
300
301         return 0;
302
303 err_out_free_srq:
304         err = mthca_HW2SW_SRQ(dev, mailbox, srq->srqn, &status);
305         if (err)
306                 mthca_warn(dev, "HW2SW_SRQ failed (%d)\n", err);
307         else if (status)
308                 mthca_warn(dev, "HW2SW_SRQ returned status 0x%02x\n", status);
309
310 err_out_free_buf:
311         if (!pd->ibpd.uobject)
312                 mthca_free_srq_buf(dev, srq);
313
314 err_out_mailbox:
315         mthca_free_mailbox(dev, mailbox);
316
317 err_out_db:
318         if (!pd->ibpd.uobject && mthca_is_memfree(dev))
319                 mthca_free_db(dev, MTHCA_DB_TYPE_SRQ, srq->db_index);
320
321 err_out_icm:
322         mthca_table_put(dev, dev->srq_table.table, srq->srqn);
323
324 err_out:
325         mthca_free(&dev->srq_table.alloc, srq->srqn);
326
327         return err;
328 }
329
330 static inline int get_srq_refcount(struct mthca_dev *dev, struct mthca_srq *srq)
331 {
332         int c;
333
334         spin_lock_irq(&dev->srq_table.lock);
335         c = srq->refcount;
336         spin_unlock_irq(&dev->srq_table.lock);
337
338         return c;
339 }
340
341 void mthca_free_srq(struct mthca_dev *dev, struct mthca_srq *srq)
342 {
343         struct mthca_mailbox *mailbox;
344         int err;
345         u8 status;
346
347         mailbox = mthca_alloc_mailbox(dev, GFP_KERNEL);
348         if (IS_ERR(mailbox)) {
349                 mthca_warn(dev, "No memory for mailbox to free SRQ.\n");
350                 return;
351         }
352
353         err = mthca_HW2SW_SRQ(dev, mailbox, srq->srqn, &status);
354         if (err)
355                 mthca_warn(dev, "HW2SW_SRQ failed (%d)\n", err);
356         else if (status)
357                 mthca_warn(dev, "HW2SW_SRQ returned status 0x%02x\n", status);
358
359         spin_lock_irq(&dev->srq_table.lock);
360         mthca_array_clear(&dev->srq_table.srq,
361                           srq->srqn & (dev->limits.num_srqs - 1));
362         --srq->refcount;
363         spin_unlock_irq(&dev->srq_table.lock);
364
365         wait_event(srq->wait, !get_srq_refcount(dev, srq));
366
367         if (!srq->ibsrq.uobject) {
368                 mthca_free_srq_buf(dev, srq);
369                 if (mthca_is_memfree(dev))
370                         mthca_free_db(dev, MTHCA_DB_TYPE_SRQ, srq->db_index);
371         }
372
373         mthca_table_put(dev, dev->srq_table.table, srq->srqn);
374         mthca_free(&dev->srq_table.alloc, srq->srqn);
375         mthca_free_mailbox(dev, mailbox);
376 }
377
378 int mthca_modify_srq(struct ib_srq *ibsrq, struct ib_srq_attr *attr,
379                      enum ib_srq_attr_mask attr_mask, struct ib_udata *udata)
380 {
381         struct mthca_dev *dev = to_mdev(ibsrq->device);
382         struct mthca_srq *srq = to_msrq(ibsrq);
383         int ret;
384         u8 status;
385
386         /* We don't support resizing SRQs (yet?) */
387         if (attr_mask & IB_SRQ_MAX_WR)
388                 return -EINVAL;
389
390         if (attr_mask & IB_SRQ_LIMIT) {
391                 u32 max_wr = mthca_is_memfree(dev) ? srq->max - 1 : srq->max;
392                 if (attr->srq_limit > max_wr)
393                         return -EINVAL;
394
395                 mutex_lock(&srq->mutex);
396                 ret = mthca_ARM_SRQ(dev, srq->srqn, attr->srq_limit, &status);
397                 mutex_unlock(&srq->mutex);
398
399                 if (ret)
400                         return ret;
401                 if (status)
402                         return -EINVAL;
403         }
404
405         return 0;
406 }
407
408 int mthca_query_srq(struct ib_srq *ibsrq, struct ib_srq_attr *srq_attr)
409 {
410         struct mthca_dev *dev = to_mdev(ibsrq->device);
411         struct mthca_srq *srq = to_msrq(ibsrq);
412         struct mthca_mailbox *mailbox;
413         struct mthca_arbel_srq_context *arbel_ctx;
414         struct mthca_tavor_srq_context *tavor_ctx;
415         u8 status;
416         int err;
417
418         mailbox = mthca_alloc_mailbox(dev, GFP_KERNEL);
419         if (IS_ERR(mailbox))
420                 return PTR_ERR(mailbox);
421
422         err = mthca_QUERY_SRQ(dev, srq->srqn, mailbox, &status);
423         if (err)
424                 goto out;
425
426         if (mthca_is_memfree(dev)) {
427                 arbel_ctx = mailbox->buf;
428                 srq_attr->srq_limit = be16_to_cpu(arbel_ctx->limit_watermark);
429         } else {
430                 tavor_ctx = mailbox->buf;
431                 srq_attr->srq_limit = be16_to_cpu(tavor_ctx->limit_watermark);
432         }
433
434         srq_attr->max_wr  = srq->max - 1;
435         srq_attr->max_sge = srq->max_gs;
436
437 out:
438         mthca_free_mailbox(dev, mailbox);
439
440         return err;
441 }
442
443 void mthca_srq_event(struct mthca_dev *dev, u32 srqn,
444                      enum ib_event_type event_type)
445 {
446         struct mthca_srq *srq;
447         struct ib_event event;
448
449         spin_lock(&dev->srq_table.lock);
450         srq = mthca_array_get(&dev->srq_table.srq, srqn & (dev->limits.num_srqs - 1));
451         if (srq)
452                 ++srq->refcount;
453         spin_unlock(&dev->srq_table.lock);
454
455         if (!srq) {
456                 mthca_warn(dev, "Async event for bogus SRQ %08x\n", srqn);
457                 return;
458         }
459
460         if (!srq->ibsrq.event_handler)
461                 goto out;
462
463         event.device      = &dev->ib_dev;
464         event.event       = event_type;
465         event.element.srq = &srq->ibsrq;
466         srq->ibsrq.event_handler(&event, srq->ibsrq.srq_context);
467
468 out:
469         spin_lock(&dev->srq_table.lock);
470         if (!--srq->refcount)
471                 wake_up(&srq->wait);
472         spin_unlock(&dev->srq_table.lock);
473 }
474
475 /*
476  * This function must be called with IRQs disabled.
477  */
478 void mthca_free_srq_wqe(struct mthca_srq *srq, u32 wqe_addr)
479 {
480         int ind;
481         struct mthca_next_seg *last_free;
482
483         ind = wqe_addr >> srq->wqe_shift;
484
485         spin_lock(&srq->lock);
486
487         last_free = get_wqe(srq, srq->last_free);
488         *wqe_to_link(last_free) = ind;
489         last_free->nda_op = htonl((ind << srq->wqe_shift) | 1);
490         *wqe_to_link(get_wqe(srq, ind)) = -1;
491         srq->last_free = ind;
492
493         spin_unlock(&srq->lock);
494 }
495
496 int mthca_tavor_post_srq_recv(struct ib_srq *ibsrq, struct ib_recv_wr *wr,
497                               struct ib_recv_wr **bad_wr)
498 {
499         struct mthca_dev *dev = to_mdev(ibsrq->device);
500         struct mthca_srq *srq = to_msrq(ibsrq);
501         unsigned long flags;
502         int err = 0;
503         int first_ind;
504         int ind;
505         int next_ind;
506         int nreq;
507         int i;
508         void *wqe;
509         void *prev_wqe;
510
511         spin_lock_irqsave(&srq->lock, flags);
512
513         first_ind = srq->first_free;
514
515         for (nreq = 0; wr; wr = wr->next) {
516                 ind       = srq->first_free;
517                 wqe       = get_wqe(srq, ind);
518                 next_ind  = *wqe_to_link(wqe);
519
520                 if (unlikely(next_ind < 0)) {
521                         mthca_err(dev, "SRQ %06x full\n", srq->srqn);
522                         err = -ENOMEM;
523                         *bad_wr = wr;
524                         break;
525                 }
526
527                 prev_wqe  = srq->last;
528                 srq->last = wqe;
529
530                 ((struct mthca_next_seg *) wqe)->ee_nds = 0;
531                 /* flags field will always remain 0 */
532
533                 wqe += sizeof (struct mthca_next_seg);
534
535                 if (unlikely(wr->num_sge > srq->max_gs)) {
536                         err = -EINVAL;
537                         *bad_wr = wr;
538                         srq->last = prev_wqe;
539                         break;
540                 }
541
542                 for (i = 0; i < wr->num_sge; ++i) {
543                         mthca_set_data_seg(wqe, wr->sg_list + i);
544                         wqe += sizeof (struct mthca_data_seg);
545                 }
546
547                 if (i < srq->max_gs)
548                         mthca_set_data_seg_inval(wqe);
549
550                 ((struct mthca_next_seg *) prev_wqe)->ee_nds =
551                         cpu_to_be32(MTHCA_NEXT_DBD);
552
553                 srq->wrid[ind]  = wr->wr_id;
554                 srq->first_free = next_ind;
555
556                 ++nreq;
557                 if (unlikely(nreq == MTHCA_TAVOR_MAX_WQES_PER_RECV_DB)) {
558                         nreq = 0;
559
560                         /*
561                          * Make sure that descriptors are written
562                          * before doorbell is rung.
563                          */
564                         wmb();
565
566                         mthca_write64(first_ind << srq->wqe_shift, srq->srqn << 8,
567                                       dev->kar + MTHCA_RECEIVE_DOORBELL,
568                                       MTHCA_GET_DOORBELL_LOCK(&dev->doorbell_lock));
569
570                         first_ind = srq->first_free;
571                 }
572         }
573
574         if (likely(nreq)) {
575                 /*
576                  * Make sure that descriptors are written before
577                  * doorbell is rung.
578                  */
579                 wmb();
580
581                 mthca_write64(first_ind << srq->wqe_shift, (srq->srqn << 8) | nreq,
582                               dev->kar + MTHCA_RECEIVE_DOORBELL,
583                               MTHCA_GET_DOORBELL_LOCK(&dev->doorbell_lock));
584         }
585
586         /*
587          * Make sure doorbells don't leak out of SRQ spinlock and
588          * reach the HCA out of order:
589          */
590         mmiowb();
591
592         spin_unlock_irqrestore(&srq->lock, flags);
593         return err;
594 }
595
596 int mthca_arbel_post_srq_recv(struct ib_srq *ibsrq, struct ib_recv_wr *wr,
597                               struct ib_recv_wr **bad_wr)
598 {
599         struct mthca_dev *dev = to_mdev(ibsrq->device);
600         struct mthca_srq *srq = to_msrq(ibsrq);
601         unsigned long flags;
602         int err = 0;
603         int ind;
604         int next_ind;
605         int nreq;
606         int i;
607         void *wqe;
608
609         spin_lock_irqsave(&srq->lock, flags);
610
611         for (nreq = 0; wr; ++nreq, wr = wr->next) {
612                 ind       = srq->first_free;
613                 wqe       = get_wqe(srq, ind);
614                 next_ind  = *wqe_to_link(wqe);
615
616                 if (unlikely(next_ind < 0)) {
617                         mthca_err(dev, "SRQ %06x full\n", srq->srqn);
618                         err = -ENOMEM;
619                         *bad_wr = wr;
620                         break;
621                 }
622
623                 ((struct mthca_next_seg *) wqe)->ee_nds = 0;
624                 /* flags field will always remain 0 */
625
626                 wqe += sizeof (struct mthca_next_seg);
627
628                 if (unlikely(wr->num_sge > srq->max_gs)) {
629                         err = -EINVAL;
630                         *bad_wr = wr;
631                         break;
632                 }
633
634                 for (i = 0; i < wr->num_sge; ++i) {
635                         mthca_set_data_seg(wqe, wr->sg_list + i);
636                         wqe += sizeof (struct mthca_data_seg);
637                 }
638
639                 if (i < srq->max_gs)
640                         mthca_set_data_seg_inval(wqe);
641
642                 srq->wrid[ind]  = wr->wr_id;
643                 srq->first_free = next_ind;
644         }
645
646         if (likely(nreq)) {
647                 srq->counter += nreq;
648
649                 /*
650                  * Make sure that descriptors are written before
651                  * we write doorbell record.
652                  */
653                 wmb();
654                 *srq->db = cpu_to_be32(srq->counter);
655         }
656
657         spin_unlock_irqrestore(&srq->lock, flags);
658         return err;
659 }
660
661 int mthca_max_srq_sge(struct mthca_dev *dev)
662 {
663         if (mthca_is_memfree(dev))
664                 return dev->limits.max_sg;
665
666         /*
667          * SRQ allocations are based on powers of 2 for Tavor,
668          * (although they only need to be multiples of 16 bytes).
669          *
670          * Therefore, we need to base the max number of sg entries on
671          * the largest power of 2 descriptor size that is <= to the
672          * actual max WQE descriptor size, rather than return the
673          * max_sg value given by the firmware (which is based on WQE
674          * sizes as multiples of 16, not powers of 2).
675          *
676          * If SRQ implementation is changed for Tavor to be based on
677          * multiples of 16, the calculation below can be deleted and
678          * the FW max_sg value returned.
679          */
680         return min_t(int, dev->limits.max_sg,
681                      ((1 << (fls(dev->limits.max_desc_sz) - 1)) -
682                       sizeof (struct mthca_next_seg)) /
683                      sizeof (struct mthca_data_seg));
684 }
685
686 int mthca_init_srq_table(struct mthca_dev *dev)
687 {
688         int err;
689
690         if (!(dev->mthca_flags & MTHCA_FLAG_SRQ))
691                 return 0;
692
693         spin_lock_init(&dev->srq_table.lock);
694
695         err = mthca_alloc_init(&dev->srq_table.alloc,
696                                dev->limits.num_srqs,
697                                dev->limits.num_srqs - 1,
698                                dev->limits.reserved_srqs);
699         if (err)
700                 return err;
701
702         err = mthca_array_init(&dev->srq_table.srq,
703                                dev->limits.num_srqs);
704         if (err)
705                 mthca_alloc_cleanup(&dev->srq_table.alloc);
706
707         return err;
708 }
709
710 void mthca_cleanup_srq_table(struct mthca_dev *dev)
711 {
712         if (!(dev->mthca_flags & MTHCA_FLAG_SRQ))
713                 return;
714
715         mthca_array_cleanup(&dev->srq_table.srq, dev->limits.num_srqs);
716         mthca_alloc_cleanup(&dev->srq_table.alloc);
717 }