xref: /titanic_52/usr/src/uts/common/io/sbp2/sbp2.c (revision 8c067cfd3aea0c49a166f9fb38114b56a9160ac6)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 /*
22  * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
23  * Use is subject to license terms.
24  */
25 
26 /*
27  * SBP2 module
28  */
29 #include <sys/param.h>
30 #include <sys/errno.h>
31 #include <sys/cred.h>
32 #include <sys/conf.h>
33 #include <sys/disp.h>
34 #include <sys/modctl.h>
35 #include <sys/stat.h>
36 #include <sys/stream.h>
37 #include <sys/strsubr.h>
38 #include <sys/strsun.h>
39 #include <sys/ddi.h>
40 #include <sys/sunddi.h>
41 
42 #include <sys/sbp2/impl.h>
43 #include <sys/1394/ieee1212.h>
44 
45 /* target routines */
46 static void	sbp2_tgt_init_sobj(sbp2_tgt_t *);
47 static void	sbp2_tgt_fini_sobj(sbp2_tgt_t *);
48 static int	sbp2_tgt_init_params(sbp2_tgt_t *);
49 static int	sbp2_tgt_init_luns(sbp2_tgt_t *, int);
50 static void	sbp2_tgt_fini_luns(sbp2_tgt_t *);
51 static int	sbp2_tgt_init_bus(sbp2_tgt_t *);
52 static void	sbp2_tgt_fini_bus(sbp2_tgt_t *);
53 static int	sbp2_tgt_mgt_request(sbp2_tgt_t *, int *);
54 static int	sbp2_tgt_task_mgt_request(sbp2_tgt_t *, uint16_t, int, uint64_t,
55 		int *);
56 
57 /* lun routines */
58 static void	sbp2_lun_logout_orb(sbp2_lun_t *, sbp2_tgt_t *, int *);
59 static boolean_t sbp2_lun_accepting_tasks(sbp2_lun_t *);
60 
61 /* session routines */
62 static int	sbp2_ses_init(sbp2_ses_t **, sbp2_lun_t *,
63 		void (*)(void *, sbp2_task_t *), void *);
64 static void	sbp2_ses_fini(sbp2_ses_t *);
65 static sbp2_task_t *sbp2_ses_orbp2task(sbp2_ses_t *, uint64_t);
66 static void	sbp2_ses_append_task(sbp2_ses_t *, sbp2_task_t *);
67 static void	sbp2_ses_reset_pending_tasks(sbp2_ses_t *, uint16_t);
68 static int	sbp2_ses_reconnect_orb(sbp2_ses_t *, int *);
69 
70 /* orb alloc routines */
71 static sbp2_bus_buf_t *sbp2_orb_freelist_get(sbp2_lun_t *, sbp2_task_t *, int);
72 static int	sbp2_orb_freelist_put(sbp2_lun_t *, sbp2_bus_buf_t *);
73 static void	sbp2_orb_freelist_destroy(sbp2_lun_t *);
74 
75 /* fetch agent routines */
76 static int	sbp2_agent_init(sbp2_agent_t *, uint64_t, sbp2_tgt_t *tp);
77 static void	sbp2_agent_fini(sbp2_agent_t *);
78 static void	sbp2_agent_acquire_locked(sbp2_agent_t *);
79 static void	sbp2_agent_release_locked(sbp2_agent_t *);
80 static void	sbp2_agent_acquire(sbp2_agent_t *);
81 static void	sbp2_agent_release(sbp2_agent_t *);
82 static int	sbp2_agent_keepalive(sbp2_agent_t *, int *);
83 static int	sbp2_agent_doorbell(sbp2_agent_t *, int *);
84 static int	sbp2_agent_write_orbp(sbp2_agent_t *, uint64_t, int *);
85 static int	sbp2_agent_reset(sbp2_agent_t *, int *);
86 
87 /* callbacks and timeouts */
88 static void	sbp2_mgt_status_fifo_wb_cb(sbp2_bus_buf_t *, void *, mblk_t **);
89 static void	sbp2_task_timeout(void *);
90 static void	sbp2_status_fifo_wb_cb(sbp2_bus_buf_t *, void *, mblk_t **);
91 
92 /* other */
93 static void	sbp2_mgt_agent_acquire(sbp2_tgt_t *);
94 static void	sbp2_mgt_agent_release(sbp2_tgt_t *);
95 static void	sbp2_fetch_agent_acquire(sbp2_ses_t *);
96 static void	sbp2_fetch_agent_release(sbp2_ses_t *);
97 
98 extern struct mod_ops mod_miscops;
99 
100 static struct modlmisc sbp2_modlmisc = {
101 	&mod_miscops,		/* module type */
102 	"Serial Bus Protocol 2 module" /* module name */
103 };
104 
105 static struct modlinkage sbp2_modlinkage = {
106 	MODREV_1, (void *)&sbp2_modlmisc, NULL
107 };
108 
109 /* tunables */
110 int	sbp2_submit_reset_nretries = 3;
111 clock_t	sbp2_submit_reset_delay = 10;	/* microsec */
112 
113 int	sbp2_write_orbp_nretries = 3;
114 clock_t	sbp2_write_orbp_delay = 10;	/* microsec */
115 
116 _NOTE(SCHEME_PROTECTS_DATA("unique per call", datab msgb))
117 
118 /*
119  *
120  * --- loadable module entry points
121  *
122  */
123 int
124 _init(void)
125 {
126 	return (mod_install(&sbp2_modlinkage));
127 }
128 
129 
130 int
131 _fini(void)
132 {
133 	return (mod_remove(&sbp2_modlinkage));
134 }
135 
136 
137 int
138 _info(struct modinfo *modinfop)
139 {
140 	return (mod_info(&sbp2_modlinkage, modinfop));
141 }
142 
143 /*
144  *
145  * --- target routines
146  *
147  */
148 int
149 sbp2_tgt_init(void *bus_hdl, sbp2_bus_t *bus, int maxluns, sbp2_tgt_t **tpp)
150 {
151 	sbp2_tgt_t	*tp;
152 	int		ret;
153 
154 	tp = kmem_zalloc(sizeof (sbp2_tgt_t), KM_SLEEP);
155 	tp->t_bus = bus;
156 	tp->t_bus_hdl = bus_hdl;
157 
158 	sbp2_tgt_init_sobj(tp);
159 
160 	if ((ret = sbp2_cfgrom_parse(tp, &tp->t_cfgrom)) != SBP2_SUCCESS) {
161 		sbp2_tgt_fini_sobj(tp);
162 		kmem_free(tp, sizeof (sbp2_tgt_t));
163 		return (SBP2_ECFGROM);
164 	}
165 
166 	if ((ret = sbp2_tgt_init_params(tp)) != SBP2_SUCCESS) {
167 		sbp2_cfgrom_free(tp, &tp->t_cfgrom);
168 		sbp2_tgt_fini_sobj(tp);
169 		kmem_free(tp, sizeof (sbp2_tgt_t));
170 		return (ret);
171 	}
172 
173 	if ((ret = sbp2_tgt_init_luns(tp, maxluns)) != SBP2_SUCCESS) {
174 		sbp2_cfgrom_free(tp, &tp->t_cfgrom);
175 		sbp2_tgt_fini_sobj(tp);
176 		kmem_free(tp, sizeof (sbp2_tgt_t));
177 		return (ret);
178 	}
179 
180 	if ((ret = sbp2_tgt_init_bus(tp)) != SBP2_SUCCESS) {
181 		sbp2_tgt_fini_luns(tp);
182 		sbp2_cfgrom_free(tp, &tp->t_cfgrom);
183 		sbp2_tgt_fini_sobj(tp);
184 		kmem_free(tp, sizeof (sbp2_tgt_t));
185 		return (ret);
186 	}
187 
188 	*tpp = tp;
189 	return (SBP2_SUCCESS);
190 }
191 
192 void
193 sbp2_tgt_fini(sbp2_tgt_t *tp)
194 {
195 	sbp2_tgt_fini_bus(tp);
196 	sbp2_tgt_fini_luns(tp);
197 	sbp2_cfgrom_free(tp, &tp->t_cfgrom);
198 	sbp2_tgt_fini_sobj(tp);
199 	kmem_free(tp, sizeof (sbp2_tgt_t));
200 }
201 
202 static void
203 sbp2_tgt_init_sobj(sbp2_tgt_t *tp)
204 {
205 	mutex_init(&tp->t_mutex, NULL, MUTEX_DRIVER, NULL);
206 	cv_init(&tp->t_mgt_agent_cv, NULL, CV_DRIVER, NULL);
207 	cv_init(&tp->t_mgt_status_cv, NULL, CV_DRIVER, NULL);
208 }
209 
210 static void
211 sbp2_tgt_fini_sobj(sbp2_tgt_t *tp)
212 {
213 	cv_destroy(&tp->t_mgt_status_cv);
214 	cv_destroy(&tp->t_mgt_agent_cv);
215 	mutex_destroy(&tp->t_mutex);
216 }
217 
218 static int
219 sbp2_tgt_init_params(sbp2_tgt_t *tp)
220 {
221 	sbp2_cfgrom_ent_t *root = &tp->t_cfgrom.cr_root;
222 	sbp2_cfgrom_ent_t *ent;
223 	uint32_t	q;
224 
225 	/* MANAGEMENT_AGENT */
226 	if ((ent = sbp2_cfgrom_ent_by_key(root, SBP2_KT_MGT_AGENT,
227 	    SBP2_KV_MGT_AGENT, 0)) == NULL) {
228 		return (SBP2_ECFGROM);
229 	}
230 	tp->t_mgt_agent = SBP2_CSR_BASE(tp) + ent->ce_data.offset * 4;
231 
232 	/* Unit_Characteristics */
233 	if ((ent = sbp2_cfgrom_ent_by_key(root, SBP2_KT_UNCHAR,
234 	    SBP2_KV_UNCHAR, 0)) == NULL) {
235 		return (SBP2_ECFGROM);
236 	}
237 	q = ent->ce_data.imm;
238 
239 	/* units of 500 ms -> ms */
240 	tp->t_mot = ((q & SBP2_UNCHAR_MOT) >> SBP2_UNCHAR_MOT_SHIFT) * 500;
241 
242 	/* quadlets -> bytes */
243 	tp->t_orb_size = (q & SBP2_UNCHAR_ORB_SIZE) * 4;
244 
245 	/* some devices return incorrect values */
246 	if (tp->t_mot < SBP2_MOT_MIN) {
247 		tp->t_mot = SBP2_MOT_DFLT;
248 	}
249 	if (tp->t_orb_size < SBP2_ORB_SIZE_MIN) {
250 		tp->t_orb_size = SBP2_ORB_SIZE_MIN;
251 	}
252 
253 	return (SBP2_SUCCESS);
254 }
255 
256 
257 /*ARGSUSED*/
258 static int
259 sbp2_tgt_init_luns(sbp2_tgt_t *tp, int maxluns)
260 {
261 	sbp2_cfgrom_ent_t *root = &tp->t_cfgrom.cr_root;
262 	sbp2_cfgrom_ent_t *ent;
263 	sbp2_lun_t	*lp;
264 	uint32_t	q;
265 
266 	ASSERT(tp->t_nluns == 0);
267 
268 	tp->t_lun = kmem_zalloc(maxluns * sizeof (sbp2_lun_t), KM_SLEEP);
269 	tp->t_nluns_alloc = maxluns;
270 
271 	/* search for Logical_Unit_Number's */
272 	for (tp->t_nluns = 0; tp->t_nluns < maxluns; tp->t_nluns++) {
273 		if ((ent = sbp2_cfgrom_ent_by_key(root, SBP2_KT_LUN,
274 		    SBP2_KV_LUN, tp->t_nluns)) == NULL) {
275 			break;
276 		}
277 		q = ent->ce_data.imm;
278 		lp = &tp->t_lun[tp->t_nluns];
279 		lp->l_tgt = tp;
280 		lp->l_lun = q & SBP2_LUN_NUM;
281 		lp->l_type = (q & SBP2_LUN_TYPE) >> SBP2_LUN_TYPE_SHIFT;
282 		mutex_init(&lp->l_orb_freelist.bl_mutex, NULL, MUTEX_DRIVER,
283 		    NULL);
284 	}
285 
286 	if (tp->t_nluns > 0) {
287 		return (SBP2_SUCCESS);
288 	} else {
289 		kmem_free(tp->t_lun, tp->t_nluns_alloc * sizeof (sbp2_lun_t));
290 		return (SBP2_ECFGROM);
291 	}
292 
293 }
294 
295 
296 static void
297 sbp2_tgt_fini_luns(sbp2_tgt_t *tp)
298 {
299 	int		i;
300 	sbp2_lun_t	*lp;
301 
302 	/* destroy each lun */
303 	for (i = 0; i < tp->t_nluns; i++) {
304 		lp = &tp->t_lun[i];
305 		sbp2_orb_freelist_destroy(lp);
306 		mutex_destroy(&lp->l_orb_freelist.bl_mutex);
307 	}
308 
309 	kmem_free(tp->t_lun, tp->t_nluns_alloc * sizeof (sbp2_lun_t));
310 }
311 
312 /*
313  * initialize bus buffers and commands
314  */
315 static int
316 sbp2_tgt_init_bus(sbp2_tgt_t *tp)
317 {
318 	int		ret;
319 
320 	/*
321 	 * We serialize management requests and reuse the same buffers.
322 	 *
323 	 * mgt ORB
324 	 */
325 	tp->t_mgt_orb_buf.bb_len =
326 	    SBP2_ORB_SIZE_ROUNDUP(tp, sizeof (sbp2_mgt_orb_t));
327 	tp->t_mgt_orb_buf.bb_flags = SBP2_BUS_BUF_DMA | SBP2_BUS_BUF_RD;
328 	if ((ret = SBP2_ALLOC_BUF(tp, &tp->t_mgt_orb_buf)) != SBP2_SUCCESS) {
329 		sbp2_tgt_fini_bus(tp);
330 		return (ret);
331 	}
332 
333 	/*
334 	 * mgt status FIFO
335 	 */
336 	tp->t_mgt_status_fifo_buf.bb_len = sizeof (sbp2_status_t);
337 	tp->t_mgt_status_fifo_buf.bb_flags = SBP2_BUS_BUF_WR_POSTED;
338 	tp->t_mgt_status_fifo_buf.bb_wb_cb = sbp2_mgt_status_fifo_wb_cb;
339 	tp->t_mgt_status_fifo_buf.bb_sbp2_priv = tp;
340 	if ((ret = SBP2_ALLOC_BUF(tp, &tp->t_mgt_status_fifo_buf)) !=
341 	    SBP2_SUCCESS) {
342 		return (ret);
343 	}
344 
345 	/*
346 	 * login response
347 	 */
348 	tp->t_mgt_login_resp_buf.bb_len =
349 	    SBP2_ORB_SIZE_ROUNDUP(tp, sizeof (sbp2_login_resp_t));
350 	/*
351 	 * read-only should have been sufficient here, but it causes
352 	 * DVMA errors on Grover, while read/write works just fine
353 	 */
354 	tp->t_mgt_login_resp_buf.bb_flags = SBP2_BUS_BUF_DMA | SBP2_BUS_BUF_RW;
355 	if ((ret = SBP2_ALLOC_BUF(tp, &tp->t_mgt_login_resp_buf)) !=
356 	    SBP2_SUCCESS) {
357 		sbp2_tgt_fini_bus(tp);
358 		return (ret);
359 	}
360 
361 	/*
362 	 * allocate bus commands
363 	 */
364 	if ((ret = SBP2_ALLOC_CMD(tp, &tp->t_mgt_cmd, 0)) != SBP2_SUCCESS) {
365 		sbp2_tgt_fini_bus(tp);
366 		return (ret);
367 	}
368 	if ((tp->t_mgt_cmd_data = allocb(8, BPRI_HI)) == NULL) {
369 		sbp2_tgt_fini_bus(tp);
370 		return (SBP2_ENOMEM);
371 	}
372 
373 	return (SBP2_SUCCESS);
374 }
375 
376 static void
377 sbp2_tgt_fini_bus(sbp2_tgt_t *tp)
378 {
379 	if (tp->t_mgt_status_fifo_buf.bb_hdl != NULL) {
380 		SBP2_FREE_BUF(tp, &tp->t_mgt_status_fifo_buf);
381 	}
382 	if (tp->t_mgt_orb_buf.bb_hdl != NULL) {
383 		SBP2_FREE_BUF(tp, &tp->t_mgt_orb_buf);
384 	}
385 	if (tp->t_mgt_login_resp_buf.bb_hdl != NULL) {
386 		SBP2_FREE_BUF(tp, &tp->t_mgt_login_resp_buf);
387 	}
388 	if (tp->t_mgt_cmd) {
389 		SBP2_FREE_CMD(tp, tp->t_mgt_cmd);
390 		tp->t_mgt_cmd = NULL;
391 	}
392 	if (tp->t_mgt_cmd_data) {
393 		freeb(tp->t_mgt_cmd_data);
394 		tp->t_mgt_cmd_data = NULL;
395 	}
396 }
397 
398 void
399 sbp2_tgt_disconnect(sbp2_tgt_t *tp)
400 {
401 	sbp2_tgt_fini_bus(tp);
402 }
403 
404 int
405 sbp2_tgt_reconnect(sbp2_tgt_t *tp)
406 {
407 	return (sbp2_tgt_init_bus(tp));
408 }
409 
410 /*
411  * send mgt ORB and wait for status
412  *
413  * mgt agent should be acquired
414  */
415 static int
416 sbp2_tgt_mgt_request(sbp2_tgt_t *tp, int *berr)
417 {
418 	clock_t		until;
419 	int		ret;
420 
421 	/*
422 	 * When a ctl operation happens from HAL - this could be 0!
423 	 * This will happen when a device is disconected and then
424 	 * reconnected. Note  there are problems with not being able
425 	 * to detach/eject a target before unplugging. That can cause
426 	 * this to happen... This problem needs some work elseware!
427 	 * This just prevents a needless panic. If we return failure
428 	 * the target ultimatly will recover and is usable.
429 	 */
430 	if (tp->t_mgt_cmd_data == 0) {
431 		return (SBP2_FAILURE);
432 	}
433 
434 	tp->t_mgt_status_rcvd = B_FALSE;
435 
436 	/* write ORB address into MANAGEMENT_AGENT */
437 	SBP2_ADDR_SET(tp->t_mgt_cmd_data->b_rptr, tp->t_mgt_orb_buf.bb_baddr,
438 	    0);
439 	tp->t_mgt_cmd_data->b_wptr = tp->t_mgt_cmd_data->b_rptr + 8;
440 
441 	if ((ret = SBP2_WB(tp, tp->t_mgt_cmd, tp->t_mgt_agent,
442 	    tp->t_mgt_cmd_data, 8, berr)) != SBP2_SUCCESS) {
443 		return (ret);
444 	}
445 
446 	/* wait for login response */
447 	mutex_enter(&tp->t_mutex);
448 	until = ddi_get_lbolt() + drv_usectohz(tp->t_mot * 1000);
449 	ret = 1;
450 
451 	while (!tp->t_mgt_status_rcvd && (ret > 0)) {
452 		ret = cv_timedwait(&tp->t_mgt_status_cv, &tp->t_mutex, until);
453 	}
454 
455 	if (!tp->t_mgt_status_rcvd) {
456 		ret = SBP2_ETIMEOUT;
457 	} else if ((tp->t_mgt_status.st_param & SBP2_ST_RESP) ==
458 	    SBP2_ST_RESP_COMPLETE) {
459 		ret = SBP2_SUCCESS;
460 	} else {
461 		ret = SBP2_FAILURE;
462 	}
463 	mutex_exit(&tp->t_mutex);
464 
465 	return (ret);
466 }
467 
468 /*
469  * Send task management request, one of:
470  *
471  *	ABORT TASK, ABORT TASK SET, LOGICAL UNIT RESET, TARGET RESET
472  */
473 static int
474 sbp2_tgt_task_mgt_request(sbp2_tgt_t *tp, uint16_t id, int func, uint64_t orbp,
475     int *berr)
476 {
477 	sbp2_task_mgt_orb_t *torb;
478 	int		ret;
479 
480 	sbp2_mgt_agent_acquire(tp);
481 
482 	torb = (sbp2_task_mgt_orb_t *)tp->t_mgt_orb_buf.bb_kaddr;
483 	bzero(torb, sizeof (sbp2_task_mgt_orb_t));
484 	SBP2_ORBP_SET(torb->to_orb, orbp);
485 	torb->to_params = SBP2_SWAP16(func | SBP2_ORB_NOTIFY |
486 	    SBP2_ORB_RQ_FMT_SBP2);
487 	torb->to_login_id = SBP2_SWAP16(id);
488 	SBP2_ADDR_SET(torb->to_status_fifo, tp->t_mgt_status_fifo_buf.bb_baddr,
489 	    0);
490 
491 	ret = sbp2_tgt_mgt_request(tp, berr);
492 
493 	sbp2_mgt_agent_release(tp);
494 
495 	return (ret);
496 }
497 
498 int
499 sbp2_tgt_reset(sbp2_tgt_t *tp, int *berr)
500 {
501 	sbp2_lun_t	*lp = &tp->t_lun[0];
502 	int		ret;
503 
504 	/* issue TARGET RESET */
505 	if ((ret = sbp2_tgt_task_mgt_request(tp, lp->l_login_resp.lr_login_id,
506 	    SBP2_ORB_MGT_FUNC_TARGET_RESET, 0, berr)) != SBP2_SUCCESS) {
507 		return (ret);
508 	}
509 
510 	return (SBP2_SUCCESS);
511 }
512 
513 int
514 sbp2_tgt_get_cfgrom(sbp2_tgt_t *tp, sbp2_cfgrom_t **crpp)
515 {
516 	*crpp = &tp->t_cfgrom;
517 	return (SBP2_SUCCESS);
518 }
519 
520 int
521 sbp2_tgt_get_lun_cnt(sbp2_tgt_t *tp)
522 {
523 	return (tp->t_nluns);
524 }
525 
526 sbp2_lun_t *
527 sbp2_tgt_get_lun(sbp2_tgt_t *tp, int num)
528 {
529 	if (num < tp->t_nluns) {
530 		return (&tp->t_lun[num]);
531 	} else {
532 		return (NULL);
533 	}
534 }
535 
536 /*
537  *
538  * --- lun routines
539  *
540  */
541 int
542 sbp2_lun_reset(sbp2_lun_t *lp, int *berr)
543 {
544 	sbp2_tgt_t	*tp = lp->l_tgt;
545 	sbp2_ses_t	*sp = lp->l_ses;
546 	sbp2_task_t	*task = NULL;
547 	int		ret;
548 
549 	/* issue LOGICAL UNIT RESET */
550 	if ((ret = sbp2_tgt_task_mgt_request(tp, lp->l_login_resp.lr_login_id,
551 	    SBP2_ORB_MGT_FUNC_LUN_RESET, 0, berr)) != SBP2_SUCCESS) {
552 		return (ret);
553 	}
554 
555 	/* mark all pending tasks reset and notify the driver */
556 	mutex_enter(&sp->s_task_mutex);
557 	for (task = sp->s_task_head; task != NULL; task = task->ts_next) {
558 		if (task->ts_state < SBP2_TASK_COMP) {
559 			task->ts_error = SBP2_TASK_ERR_LUN_RESET;
560 			task->ts_state = SBP2_TASK_COMP;
561 		}
562 	}
563 	mutex_exit(&sp->s_task_mutex);
564 
565 	sp->s_status_cb(sp->s_status_cb_arg, NULL);
566 
567 	return (SBP2_SUCCESS);
568 }
569 
570 int
571 sbp2_lun_login(sbp2_lun_t *lp, sbp2_ses_t **spp,
572     void (*cb)(void *, sbp2_task_t *), void *cb_arg, int *berr)
573 {
574 	sbp2_tgt_t	*tp = lp->l_tgt;
575 	sbp2_ses_t	*sp;
576 	sbp2_login_orb_t *lorb;
577 	int		ret;
578 
579 	if (cb == NULL) {
580 		return (SBP2_EINVAL);
581 	}
582 
583 	/* multiple sessions not supported yet */
584 	if (lp->l_ses != NULL) {
585 		return (SBP2_EALREADY);
586 	}
587 
588 	if ((ret = sbp2_ses_init(&sp, lp, cb, cb_arg)) != SBP2_SUCCESS) {
589 		return (ret);
590 	}
591 	lp->l_ses = sp;
592 
593 	sbp2_mgt_agent_acquire(tp);
594 
595 	/* prepare login ORB */
596 	mutex_enter(&tp->t_mutex);
597 	lorb = (sbp2_login_orb_t *)tp->t_mgt_orb_buf.bb_kaddr;
598 	bzero(lorb, sizeof (sbp2_login_orb_t));
599 	SBP2_ADDR_SET(lorb->lo_resp, tp->t_mgt_login_resp_buf.bb_baddr, 0);
600 	lorb->lo_params = SBP2_SWAP16(SBP2_ORB_MGT_FUNC_LOGIN |
601 	    SBP2_ORB_LOGIN_EXCL | SBP2_ORB_NOTIFY | SBP2_ORB_RQ_FMT_SBP2);
602 	lorb->lo_lun = SBP2_SWAP16(lp->l_lun);
603 	lorb->lo_resp_len = SBP2_SWAP16(tp->t_mgt_login_resp_buf.bb_len);
604 	SBP2_ADDR_SET(lorb->lo_status_fifo, sp->s_status_fifo_buf.bb_baddr, 0);
605 
606 	bzero(tp->t_mgt_login_resp_buf.bb_kaddr, sizeof (sbp2_login_resp_t));
607 
608 	lp->l_logged_in = B_FALSE;
609 	mutex_exit(&tp->t_mutex);
610 
611 	/* send request */
612 	if ((ret = sbp2_tgt_mgt_request(tp, berr)) != SBP2_SUCCESS) {
613 		sbp2_mgt_agent_release(tp);
614 		sbp2_ses_fini(lp->l_ses);
615 		lp->l_ses = NULL;
616 		return (ret);
617 	}
618 
619 	/* retrieve response data (XXX sanity checks?) */
620 	mutex_enter(&tp->t_mutex);
621 	(void) SBP2_SYNC_BUF(tp, &tp->t_mgt_login_resp_buf, 0, 0,
622 	    DDI_DMA_SYNC_FORKERNEL);
623 	bcopy(tp->t_mgt_login_resp_buf.bb_kaddr, &lp->l_login_resp,
624 	    sizeof (sbp2_login_resp_t));
625 
626 	/* convert from BE to native endianness */
627 	SBP2_SWAP16_1(lp->l_login_resp.lr_len);
628 	SBP2_SWAP16_1(lp->l_login_resp.lr_login_id);
629 	SBP2_SWAP32_2(lp->l_login_resp.lr_cmd_agent);
630 	SBP2_SWAP16_1(lp->l_login_resp.lr_reconnect_hold);
631 	lp->l_login_resp.lr_reconnect_hold++;
632 
633 	sp->s_agent_offset = SBP2_ADDR2UINT64(lp->l_login_resp.lr_cmd_agent);
634 
635 	lp->l_logged_in = B_TRUE;
636 	mutex_exit(&tp->t_mutex);
637 
638 	sbp2_mgt_agent_release(tp);
639 
640 	if ((ret = sbp2_agent_init(&sp->s_agent, sp->s_agent_offset, tp)) !=
641 	    SBP2_SUCCESS) {
642 		sbp2_ses_fini(sp);
643 		lp->l_ses = NULL;
644 		return (ret);
645 	}
646 
647 	*spp = lp->l_ses;
648 	return (SBP2_SUCCESS);
649 }
650 
651 /*ARGSUSED*/
652 int
653 sbp2_lun_logout(sbp2_lun_t *lp, sbp2_ses_t **sp, int *berr, boolean_t phys)
654 {
655 	sbp2_tgt_t	*tp = lp->l_tgt;
656 
657 	ASSERT(*sp == lp->l_ses);
658 
659 	mutex_enter(&tp->t_mutex);
660 	if (lp->l_logged_in) {
661 		lp->l_logged_in = B_FALSE;
662 		/* do physical LOGOUT if requested */
663 		if (phys) {
664 			mutex_exit(&tp->t_mutex);
665 			sbp2_lun_logout_orb(lp, tp, berr);
666 			mutex_enter(&tp->t_mutex);
667 		}
668 	}
669 
670 	sbp2_agent_fini(&lp->l_ses->s_agent);
671 	sbp2_ses_fini(lp->l_ses);
672 	lp->l_ses = NULL;
673 	*sp = NULL;
674 	mutex_exit(&tp->t_mutex);
675 
676 	return (SBP2_SUCCESS);
677 }
678 
679 /*
680  * Issue LOGOUT mgt orb and wait for response. We are not interested in
681  * the success at the time, since the device may be disconnected or hung,
682  * just trying to make the best effort.
683  */
684 static void
685 sbp2_lun_logout_orb(sbp2_lun_t *lp, sbp2_tgt_t *tp, int *berr)
686 {
687 	sbp2_logout_orb_t *lorb;
688 
689 	sbp2_mgt_agent_acquire(tp);
690 
691 	/* prepare logout ORB */
692 	lorb = (sbp2_logout_orb_t *)tp->t_mgt_orb_buf.bb_kaddr;
693 	bzero(lorb, sizeof (sbp2_logout_orb_t));
694 	lorb->lo_params = SBP2_SWAP16(SBP2_ORB_MGT_FUNC_LOGOUT |
695 	    SBP2_ORB_NOTIFY | SBP2_ORB_RQ_FMT_SBP2);
696 	lorb->lo_login_id = SBP2_SWAP16(lp->l_login_resp.lr_login_id);
697 	SBP2_ADDR_SET(lorb->lo_status_fifo, tp->t_mgt_status_fifo_buf.bb_baddr,
698 	    0);
699 
700 	/* send request */
701 	(void) sbp2_tgt_mgt_request(tp, berr);
702 
703 	sbp2_mgt_agent_release(tp);
704 }
705 
706 static boolean_t
707 sbp2_lun_accepting_tasks(sbp2_lun_t *lp)
708 {
709 	sbp2_tgt_t	*tp = lp->l_tgt;
710 	boolean_t	ret;
711 
712 	mutex_enter(&tp->t_mutex);
713 	ret = ((lp->l_ses != NULL) && lp->l_logged_in && !lp->l_reconnecting);
714 	mutex_exit(&tp->t_mutex);
715 	return (ret);
716 }
717 
718 /*
719  *
720  * --- session routines
721  *
722  */
723 static int
724 sbp2_ses_init(sbp2_ses_t **spp, sbp2_lun_t *lp,
725     void (*cb)(void *, sbp2_task_t *), void *cb_arg)
726 {
727 	sbp2_tgt_t	*tp = lp->l_tgt;
728 	sbp2_ses_t	*sp;
729 	int		ret;
730 
731 	sp = kmem_zalloc(sizeof (sbp2_ses_t), KM_SLEEP);
732 
733 	sp->s_tgt = tp;
734 	sp->s_lun = lp;
735 	sp->s_status_cb = cb;
736 	sp->s_status_cb_arg = cb_arg;
737 
738 	mutex_init(&sp->s_mutex, NULL, MUTEX_DRIVER,
739 	    SBP2_GET_IBLOCK_COOKIE(tp));
740 	mutex_init(&sp->s_task_mutex, NULL, MUTEX_DRIVER,
741 	    SBP2_GET_IBLOCK_COOKIE(tp));
742 
743 	/*
744 	 * status FIFO for block requests
745 	 */
746 	sp->s_status_fifo_buf.bb_len = sizeof (sbp2_status_t);
747 	sp->s_status_fifo_buf.bb_flags = SBP2_BUS_BUF_WR_POSTED;
748 	sp->s_status_fifo_buf.bb_wb_cb = sbp2_status_fifo_wb_cb;
749 	sp->s_status_fifo_buf.bb_sbp2_priv = sp;
750 	if ((ret = SBP2_ALLOC_BUF(tp, &sp->s_status_fifo_buf)) !=
751 	    SBP2_SUCCESS) {
752 		sbp2_ses_fini(sp);
753 		return (ret);
754 	}
755 
756 	*spp = sp;
757 	return (SBP2_SUCCESS);
758 }
759 
760 
761 static void
762 sbp2_ses_fini(sbp2_ses_t *sp)
763 {
764 	sbp2_tgt_t	*tp = sp->s_lun->l_tgt;
765 
766 	if (sp->s_status_fifo_buf.bb_hdl != NULL) {
767 		SBP2_FREE_BUF(tp, &sp->s_status_fifo_buf);
768 	}
769 
770 	mutex_destroy(&sp->s_task_mutex);
771 	mutex_destroy(&sp->s_mutex);
772 
773 	kmem_free(sp, sizeof (sbp2_ses_t));
774 }
775 
776 int
777 sbp2_ses_reconnect(sbp2_ses_t *sp, int *berr, uint16_t nodeID)
778 {
779 	sbp2_tgt_t	*tp = sp->s_tgt;
780 	sbp2_lun_t	*lp = sp->s_lun;
781 	int		ret;
782 
783 	/* prevent new tasks from being submitted */
784 	mutex_enter(&tp->t_mutex);
785 	lp->l_reconnecting = B_TRUE;
786 	mutex_exit(&tp->t_mutex);
787 
788 	/*
789 	 * From 10.5 Task management event matrix:
790 	 *	Immediately upon detection of a bus reset, all command
791 	 *	block fetch agents transition to the reset state and
792 	 *	their associated task sets are cleared without
793 	 *	the return of completion status.
794 	 *
795 	 * Reset pending tasks so we can retry them later.
796 	 */
797 	sbp2_ses_reset_pending_tasks(sp, nodeID);
798 
799 	ret = sbp2_ses_reconnect_orb(sp, berr);
800 
801 	mutex_enter(&tp->t_mutex);
802 	lp->l_reconnecting = B_FALSE;
803 	mutex_exit(&tp->t_mutex);
804 
805 	return (ret);
806 }
807 
808 /*
809  * Send reconnect ORB. If operation fails, set lp->l_logged_in = B_FALSE.
810  */
811 static int
812 sbp2_ses_reconnect_orb(sbp2_ses_t *sp, int *berr)
813 {
814 	sbp2_tgt_t	*tp = sp->s_tgt;
815 	sbp2_lun_t	*lp = sp->s_lun;
816 	sbp2_agent_t	*ap = &sp->s_agent;
817 	sbp2_reconnect_orb_t *rorb;
818 	int		ret;
819 
820 	sbp2_mgt_agent_acquire(tp);
821 
822 	/* prepare login ORB */
823 	rorb = (sbp2_reconnect_orb_t *)tp->t_mgt_orb_buf.bb_kaddr;
824 	bzero(rorb, sizeof (sbp2_reconnect_orb_t));
825 	rorb->ro_params = SBP2_SWAP16(SBP2_ORB_MGT_FUNC_RECONNECT |
826 	    SBP2_ORB_NOTIFY | SBP2_ORB_RQ_FMT_SBP2);
827 	rorb->ro_login_id = SBP2_SWAP16(lp->l_login_resp.lr_login_id);
828 	SBP2_ADDR_SET(rorb->ro_status_fifo, tp->t_mgt_status_fifo_buf.bb_baddr,
829 	    0);
830 
831 	/* send request */
832 	if ((ret = sbp2_tgt_mgt_request(tp, berr)) != SBP2_SUCCESS) {
833 		mutex_enter(&tp->t_mutex);
834 		lp->l_logged_in = B_FALSE;
835 		mutex_exit(&tp->t_mutex);
836 	} else {
837 		/* after successful reset fetch agent is in RESET state */
838 		mutex_enter(&ap->a_mutex);
839 		ap->a_state = SBP2_AGENT_STATE_RESET;
840 		mutex_exit(&ap->a_mutex);
841 	}
842 
843 	sbp2_mgt_agent_release(tp);
844 
845 	return (ret);
846 }
847 
848 
849 static sbp2_task_t *
850 sbp2_ses_orbp2task(sbp2_ses_t *sp, uint64_t orbp)
851 {
852 	sbp2_task_t	*task;
853 
854 	mutex_enter(&sp->s_task_mutex);
855 	for (task = sp->s_task_head; task != NULL; task = task->ts_next) {
856 		if (task->ts_buf->bb_baddr == orbp) {
857 			break;
858 		}
859 	}
860 	mutex_exit(&sp->s_task_mutex);
861 	return (task);
862 }
863 
864 /*
865  * This is where tasks (command ORB's) are signalled to the target.
866  * 'task' argument is allowed to be NULL, in which case the task will be
867  * taken from the current task list.
868  *
869  * Tasks are signalled one at a time by writing into ORB_POINTER register.
870  * While SBP-2 allows dynamic task list updates and using DOORBELL register,
871  * some devices have bugs that prevent using this strategy: e.g. some LaCie
872  * HDD's can corrupt data. Data integrity is more important than performance.
873  */
874 int
875 sbp2_ses_submit_task(sbp2_ses_t *sp, sbp2_task_t *new_task)
876 {
877 	sbp2_agent_t	*ap = &sp->s_agent;
878 	sbp2_tgt_t	*tp = sp->s_tgt;
879 	sbp2_task_t	*task;		/* task actually being submitted */
880 	boolean_t	callback;
881 	timeout_id_t	timeout_id;
882 	int		ret;
883 
884 	if (!sbp2_lun_accepting_tasks(sp->s_lun)) {
885 		return (SBP2_ENODEV);
886 	}
887 
888 	sbp2_agent_acquire(ap);	/* serialize */
889 
890 	mutex_enter(&ap->a_mutex);
891 
892 	/* if task provided, append it to the list */
893 	if (new_task != NULL) {
894 		ASSERT(new_task->ts_state == SBP2_TASK_INIT);
895 		sbp2_ses_append_task(sp, new_task);
896 	}
897 
898 	/* if there is already a task in flight, exit */
899 	if ((ap->a_active_task != NULL) &&
900 	    (ap->a_active_task->ts_state == SBP2_TASK_PEND)) {
901 		mutex_exit(&ap->a_mutex);
902 		sbp2_agent_release(ap);
903 		return (SBP2_SUCCESS);
904 	}
905 
906 	/*
907 	 * cannot submit tasks from interrupt context,
908 	 * upper layer driver is responsible to call nudge
909 	 */
910 	if (servicing_interrupt()) {
911 		mutex_exit(&ap->a_mutex);
912 		sbp2_agent_release(ap);
913 		return (SBP2_ECONTEXT);
914 	}
915 
916 	/* no active task, grab the first one on the list in INIT state */
917 	ap->a_active_task = sbp2_ses_find_task_state(sp, SBP2_TASK_INIT);
918 	if (ap->a_active_task == NULL) {
919 		mutex_exit(&ap->a_mutex);
920 		sbp2_agent_release(ap);
921 		return (SBP2_SUCCESS);
922 	}
923 	task = ap->a_active_task;
924 	task->ts_ses = sp;
925 	task->ts_state = SBP2_TASK_PEND;
926 
927 	/* can't work with a dead agent */
928 	if (sbp2_agent_keepalive(ap, &task->ts_bus_error) != SBP2_SUCCESS) {
929 		task->ts_error = SBP2_TASK_ERR_DEAD;
930 		goto error;
931 	}
932 
933 	/*
934 	 * In theory, we should schedule task timeout after it's been submitted.
935 	 * However, some fast tasks complete even before timeout is scheduled.
936 	 * To avoid additional complications in the code, schedule timeout now.
937 	 */
938 	ASSERT(task->ts_timeout_id == 0);
939 	task->ts_time_start = gethrtime();
940 	if (task->ts_timeout > 0) {
941 		task->ts_timeout_id = timeout(sbp2_task_timeout, task,
942 		    task->ts_timeout * drv_usectohz(1000000));
943 	}
944 
945 	/* notify fetch agent */
946 	ap->a_state = SBP2_AGENT_STATE_ACTIVE;
947 	mutex_exit(&ap->a_mutex);
948 	ret = sbp2_agent_write_orbp(ap, task->ts_buf->bb_baddr,
949 	    &task->ts_bus_error);
950 	tp->t_stat.stat_submit_orbp++;
951 	mutex_enter(&ap->a_mutex);
952 
953 	if (ret != SBP2_SUCCESS) {
954 		ap->a_state = SBP2_AGENT_STATE_DEAD;
955 		tp->t_stat.stat_status_dead++;
956 
957 		if (task->ts_timeout_id != 0) {
958 			timeout_id = task->ts_timeout_id;
959 			task->ts_timeout_id = 0;
960 			(void) untimeout(timeout_id);
961 		}
962 		task->ts_error = SBP2_TASK_ERR_BUS;
963 		goto error;
964 	}
965 
966 	mutex_exit(&ap->a_mutex);
967 
968 	sbp2_agent_release(ap);
969 	return (SBP2_SUCCESS);
970 
971 error:
972 	/*
973 	 * Return immediate error if failed task is the one being submitted,
974 	 * otherwise use callback.
975 	 */
976 	callback = (ap->a_active_task != new_task);
977 	ASSERT(task == ap->a_active_task);
978 	ap->a_active_task = NULL;
979 	mutex_exit(&ap->a_mutex);
980 	sbp2_agent_release(ap);
981 
982 	/*
983 	 * Remove task from the list. It is important not to change task state
984 	 * to SBP2_TASK_COMP while it's still on the list, to avoid race with
985 	 * upper layer driver (e.g. scsa1394).
986 	 */
987 	ret = sbp2_ses_remove_task(sp, task);
988 	ASSERT(ret == SBP2_SUCCESS);
989 	task->ts_state = SBP2_TASK_COMP;
990 
991 	if (callback) {
992 		sp->s_status_cb(sp->s_status_cb_arg, task);
993 		return (SBP2_SUCCESS);
994 	} else {
995 		/* upper layer driver is responsible to call nudge */
996 		return (SBP2_FAILURE);
997 	}
998 }
999 
1000 void
1001 sbp2_ses_nudge(sbp2_ses_t *sp)
1002 {
1003 	(void) sbp2_ses_submit_task(sp, NULL);
1004 }
1005 
1006 /*
1007  * append task to the task list
1008  */
1009 static void
1010 sbp2_ses_append_task(sbp2_ses_t *sp, sbp2_task_t *task)
1011 {
1012 	sbp2_tgt_t	*tp = sp->s_tgt;
1013 
1014 	mutex_enter(&sp->s_task_mutex);
1015 	if (sp->s_task_head == NULL) {
1016 		ASSERT(sp->s_task_tail == NULL);
1017 		ASSERT(sp->s_task_cnt == 0);
1018 		task->ts_prev = task->ts_next = NULL;
1019 		sp->s_task_head = sp->s_task_tail = task;
1020 	} else {
1021 		ASSERT(sp->s_task_cnt > 0);
1022 		task->ts_next = NULL;
1023 		task->ts_prev = sp->s_task_tail;
1024 		sp->s_task_tail->ts_next = task;
1025 		sp->s_task_tail = task;
1026 	}
1027 	ASSERT(task != task->ts_prev);
1028 	ASSERT(task != task->ts_next);
1029 
1030 	sp->s_task_cnt++;
1031 	if (sp->s_task_cnt > tp->t_stat.stat_task_max) {
1032 		tp->t_stat.stat_task_max = sp->s_task_cnt;
1033 	}
1034 	mutex_exit(&sp->s_task_mutex);
1035 }
1036 
1037 /*
1038  * remove task from the task list
1039  */
1040 static int
1041 sbp2_ses_remove_task_locked(sbp2_ses_t *sp, sbp2_task_t *task)
1042 {
1043 	sp->s_task_cnt--;
1044 	if (task == sp->s_task_head) {			/* first */
1045 		ASSERT(task->ts_prev == NULL);
1046 		if (task->ts_next == NULL) {		/*   and last */
1047 			ASSERT(sp->s_task_cnt == 0);
1048 			sp->s_task_head = sp->s_task_tail = NULL;
1049 		} else {				/*   but not last */
1050 			sp->s_task_head = task->ts_next;
1051 			sp->s_task_head->ts_prev = NULL;
1052 		}
1053 	} else if (task == sp->s_task_tail) {		/* last but not first */
1054 		ASSERT(task->ts_next == NULL);
1055 		sp->s_task_tail = task->ts_prev;
1056 		sp->s_task_tail->ts_next = NULL;
1057 	} else {					/* in the middle */
1058 		task->ts_prev->ts_next = task->ts_next;
1059 		task->ts_next->ts_prev = task->ts_prev;
1060 	}
1061 	task->ts_prev = task->ts_next = NULL;
1062 	ASSERT(sp->s_task_cnt >= 0);
1063 
1064 	return (SBP2_SUCCESS);
1065 }
1066 
1067 int
1068 sbp2_ses_remove_task(sbp2_ses_t *sp, sbp2_task_t *task)
1069 {
1070 	int	ret;
1071 
1072 	mutex_enter(&sp->s_task_mutex);
1073 	ret = sbp2_ses_remove_task_locked(sp, task);
1074 	mutex_exit(&sp->s_task_mutex);
1075 
1076 	return (ret);
1077 }
1078 
1079 /*
1080  * Return first task on the list in specified state.
1081  */
1082 sbp2_task_t *
1083 sbp2_ses_find_task_state(sbp2_ses_t *sp, sbp2_task_state_t state)
1084 {
1085 	sbp2_task_t	*task = NULL;
1086 
1087 	mutex_enter(&sp->s_task_mutex);
1088 	for (task = sp->s_task_head; task != NULL; task = task->ts_next) {
1089 		if (task->ts_state == state) {
1090 			break;
1091 		}
1092 	}
1093 	mutex_exit(&sp->s_task_mutex);
1094 
1095 	return (task);
1096 }
1097 
1098 /*
1099  * Remove first task on the list. Returns pointer to the removed task or NULL.
1100  */
1101 sbp2_task_t *
1102 sbp2_ses_remove_first_task(sbp2_ses_t *sp)
1103 {
1104 	sbp2_task_t	*task = NULL;
1105 
1106 	mutex_enter(&sp->s_task_mutex);
1107 	task = sp->s_task_head;
1108 	if (task != NULL) {
1109 		(void) sbp2_ses_remove_task_locked(sp, task);
1110 	}
1111 	mutex_exit(&sp->s_task_mutex);
1112 
1113 	return (task);
1114 }
1115 
1116 /*
1117  * Remove first task on the list only if it's in specified state.
1118  * Returns pointer to the removed task or NULL.
1119  */
1120 sbp2_task_t *
1121 sbp2_ses_remove_first_task_state(sbp2_ses_t *sp, sbp2_task_state_t state)
1122 {
1123 	sbp2_task_t	*task = NULL;
1124 
1125 	mutex_enter(&sp->s_task_mutex);
1126 	if ((sp->s_task_head != NULL) && (sp->s_task_head->ts_state == state)) {
1127 		task = sp->s_task_head;
1128 		(void) sbp2_ses_remove_task_locked(sp, task);
1129 	}
1130 	mutex_exit(&sp->s_task_mutex);
1131 
1132 	return (task);
1133 }
1134 
1135 /*
1136  * Remove first task on the list. If there's timeout, untimeout it.
1137  * Returns pointer to the removed task or NULL.
1138  */
1139 sbp2_task_t *
1140 sbp2_ses_cancel_first_task(sbp2_ses_t *sp)
1141 {
1142 	sbp2_task_t	*task = NULL;
1143 	timeout_id_t	timeout_id;
1144 
1145 	mutex_enter(&sp->s_task_mutex);
1146 	task = sp->s_task_head;
1147 	if (task != NULL) {
1148 		(void) sbp2_ses_remove_task_locked(sp, task);
1149 	}
1150 	mutex_exit(&sp->s_task_mutex);
1151 
1152 	if ((task != NULL) && ((timeout_id = task->ts_timeout_id) != 0)) {
1153 		task->ts_timeout_id = 0;
1154 		(void) untimeout(timeout_id);
1155 	}
1156 
1157 	return (task);
1158 }
1159 
1160 /*
1161  * Reset pending tasks on the list to their initial state.
1162  */
1163 static void
1164 sbp2_ses_reset_pending_tasks(sbp2_ses_t *sp, uint16_t nodeID)
1165 {
1166 	sbp2_agent_t	*ap = &sp->s_agent;
1167 	sbp2_task_t	*task = NULL;
1168 	timeout_id_t	timeout_id;
1169 	sbp2_cmd_orb_t	*orb;
1170 
1171 	mutex_enter(&sp->s_task_mutex);
1172 	for (task = sp->s_task_head; task != NULL; task = task->ts_next) {
1173 		task->ts_state = SBP2_TASK_INIT;
1174 
1175 		/* cancel timeout */
1176 		if ((timeout_id = task->ts_timeout_id) != 0) {
1177 			task->ts_timeout_id = 0;
1178 			(void) untimeout(timeout_id);
1179 		}
1180 
1181 		/* update ORB nodeID */
1182 		orb = (sbp2_cmd_orb_t *)sbp2_task_orb_kaddr(task);
1183 		*(uint16_t *)orb->co_data_descr = SBP2_SWAP16(nodeID);
1184 		sbp2_task_orb_sync(sp->s_lun, task, DDI_DMA_SYNC_FORDEV);
1185 	}
1186 	mutex_exit(&sp->s_task_mutex);
1187 
1188 	mutex_enter(&ap->a_mutex);
1189 	ap->a_active_task = NULL;
1190 	mutex_exit(&ap->a_mutex);
1191 }
1192 
1193 int
1194 sbp2_ses_agent_reset(sbp2_ses_t *sp, int *berr)
1195 {
1196 	return (sbp2_agent_reset(&sp->s_agent, berr));
1197 }
1198 
1199 int
1200 sbp2_ses_abort_task(sbp2_ses_t *sp, sbp2_task_t *task, int *berr)
1201 {
1202 	sbp2_tgt_t	*tp = sp->s_tgt;
1203 	sbp2_lun_t	*lp = sp->s_lun;
1204 	uint16_t	params;
1205 	sbp2_cmd_orb_t	*orb = (sbp2_cmd_orb_t *)task->ts_buf->bb_kaddr;
1206 	int		ret = SBP2_SUCCESS;
1207 
1208 	/* mark ORB as dummy ORB */
1209 	params = (orb->co_params & ~SBP2_ORB_RQ_FMT) | SBP2_ORB_RQ_FMT_DUMMY;
1210 	orb->co_params = params;
1211 	(void) SBP2_SYNC_BUF(tp, task->ts_buf, 0, 0, DDI_DMA_SYNC_FORDEV);
1212 
1213 	ret = sbp2_tgt_task_mgt_request(tp, lp->l_login_resp.lr_login_id,
1214 	    SBP2_ORB_MGT_FUNC_ABORT_TASK, task->ts_buf->bb_baddr, berr);
1215 
1216 	return (ret);
1217 }
1218 
1219 
1220 int
1221 sbp2_ses_abort_task_set(sbp2_ses_t *sp, int *berr)
1222 {
1223 	sbp2_tgt_t	*tp = sp->s_tgt;
1224 	sbp2_lun_t	*lp = sp->s_lun;
1225 	int		ret;
1226 
1227 	ret = sbp2_tgt_task_mgt_request(tp, lp->l_login_resp.lr_login_id,
1228 	    SBP2_ORB_MGT_FUNC_ABORT_TASK_SET, 0, berr);
1229 
1230 	return (ret);
1231 }
1232 
1233 
1234 /*
1235  *
1236  * ORB functions
1237  *
1238  * allocate ORB resources
1239  *
1240  * we maintain a freelist of ORB's for faster allocation
1241  */
1242 /*ARGSUSED*/
1243 static sbp2_bus_buf_t *
1244 sbp2_orb_freelist_get(sbp2_lun_t *lp, sbp2_task_t *task, int len)
1245 {
1246 	sbp2_buf_list_t	*bl = &lp->l_orb_freelist;
1247 	sbp2_bus_buf_t	*buf = NULL;
1248 
1249 	mutex_enter(&bl->bl_mutex);
1250 	if ((bl->bl_head != NULL) && (bl->bl_head->bb_len == len)) {
1251 		buf = bl->bl_head;
1252 		bl->bl_head = buf->bb_next;
1253 		if (bl->bl_tail == buf) {	/* last one? */
1254 			ASSERT(bl->bl_head == NULL);
1255 			bl->bl_tail = NULL;
1256 		}
1257 		bl->bl_len--;
1258 		buf->bb_next = NULL;
1259 	}
1260 	mutex_exit(&bl->bl_mutex);
1261 
1262 	return (buf);
1263 }
1264 
1265 static int
1266 sbp2_orb_freelist_put(sbp2_lun_t *lp, sbp2_bus_buf_t *buf)
1267 {
1268 	sbp2_buf_list_t	*bl = &lp->l_orb_freelist;
1269 	int		ret;
1270 
1271 	mutex_enter(&bl->bl_mutex);
1272 	if (bl->bl_len < SBP2_ORB_FREELIST_MAX) {
1273 		if (bl->bl_head == NULL) {
1274 			ASSERT(bl->bl_tail == NULL);
1275 			bl->bl_head = bl->bl_tail = buf;
1276 		} else {
1277 			bl->bl_tail->bb_next = buf;
1278 			bl->bl_tail = buf;
1279 		}
1280 		buf->bb_next = NULL;
1281 		bl->bl_len++;
1282 		ret = SBP2_SUCCESS;
1283 	} else {
1284 		ret = SBP2_FAILURE;
1285 	}
1286 	mutex_exit(&bl->bl_mutex);
1287 
1288 	return (ret);
1289 }
1290 
1291 static void
1292 sbp2_orb_freelist_destroy(sbp2_lun_t *lp)
1293 {
1294 	sbp2_tgt_t	*tp = lp->l_tgt;
1295 	sbp2_buf_list_t	*bl = &lp->l_orb_freelist;
1296 	sbp2_bus_buf_t	*buf, *buf_next;
1297 
1298 	mutex_enter(&bl->bl_mutex);
1299 	for (buf = bl->bl_head; buf != NULL; ) {
1300 		SBP2_FREE_BUF(tp, buf);
1301 		buf_next = buf->bb_next;
1302 		kmem_free(buf, sizeof (sbp2_bus_buf_t));
1303 		buf = buf_next;
1304 	}
1305 	bl->bl_head = bl->bl_tail = NULL;
1306 	mutex_exit(&bl->bl_mutex);
1307 }
1308 
1309 int
1310 sbp2_task_orb_alloc(sbp2_lun_t *lp, sbp2_task_t *task, int len)
1311 {
1312 	sbp2_tgt_t	*tp = lp->l_tgt;
1313 	int		buf_len;
1314 	int		ret;
1315 
1316 	buf_len = SBP2_ORB_SIZE_ROUNDUP(tp, len);
1317 
1318 	/* try freelist first */
1319 	if ((task->ts_buf = sbp2_orb_freelist_get(lp, task, buf_len)) != NULL) {
1320 		return (SBP2_SUCCESS);
1321 	}
1322 
1323 	/* if no free buffers, allocate new */
1324 	task->ts_buf = kmem_zalloc(sizeof (sbp2_bus_buf_t), KM_SLEEP);
1325 	task->ts_buf->bb_len = buf_len;
1326 	task->ts_buf->bb_flags = SBP2_BUS_BUF_DMA | SBP2_BUS_BUF_RD;
1327 	if ((ret = SBP2_ALLOC_BUF(tp, task->ts_buf)) != SBP2_SUCCESS) {
1328 		kmem_free(task->ts_buf, sizeof (sbp2_bus_buf_t));
1329 		task->ts_buf = NULL;
1330 	}
1331 
1332 	return (ret);
1333 }
1334 
1335 void
1336 sbp2_task_orb_free(sbp2_lun_t *lp, sbp2_task_t *task)
1337 {
1338 	sbp2_tgt_t	*tp = lp->l_tgt;
1339 
1340 	if (task->ts_buf != NULL) {
1341 		if (sbp2_orb_freelist_put(lp, task->ts_buf) != SBP2_SUCCESS) {
1342 			SBP2_FREE_BUF(tp, task->ts_buf);
1343 			kmem_free(task->ts_buf, sizeof (sbp2_bus_buf_t));
1344 		}
1345 		task->ts_buf = NULL;
1346 	}
1347 }
1348 
1349 void *
1350 sbp2_task_orb_kaddr(sbp2_task_t *task)
1351 {
1352 	return (task->ts_buf->bb_kaddr);
1353 }
1354 
1355 void
1356 sbp2_task_orb_sync(sbp2_lun_t *lp, sbp2_task_t *task, int flags)
1357 {
1358 	(void) SBP2_SYNC_BUF(lp->l_tgt, task->ts_buf, 0, 0, flags);
1359 }
1360 
1361 /*
1362  *
1363  * --- fetch agent routines
1364  *
1365  */
1366 static int
1367 sbp2_agent_init(sbp2_agent_t *ap, uint64_t offset, sbp2_tgt_t *tp)
1368 {
1369 	int	ret;
1370 
1371 	/* paranoia */
1372 	if (offset == 0) {
1373 		return (SBP2_FAILURE);
1374 	}
1375 
1376 	ap->a_tgt = tp;
1377 
1378 	ap->a_reg_agent_state = offset + SBP2_AGENT_STATE_OFFSET;
1379 	ap->a_reg_agent_reset = offset + SBP2_AGENT_RESET_OFFSET;
1380 	ap->a_reg_orbp = offset + SBP2_ORB_POINTER_OFFSET;
1381 	ap->a_reg_doorbell = offset + SBP2_DOORBELL_OFFSET;
1382 	ap->a_reg_unsol_status_enable = offset +
1383 	    SBP2_UNSOLICITED_STATUS_ENABLE_OFFSET;
1384 
1385 	/*
1386 	 * allocate bus commands
1387 	 */
1388 	if ((ret = SBP2_ALLOC_CMD(tp, &ap->a_cmd, 0)) != SBP2_SUCCESS) {
1389 		return (ret);
1390 	}
1391 	ap->a_cmd_data = allocb(sizeof (sbp2_orbp_t), BPRI_HI);
1392 	if (ap->a_cmd_data == NULL) {
1393 		sbp2_agent_fini(ap);
1394 		return (SBP2_ENOMEM);
1395 	}
1396 
1397 	mutex_init(&ap->a_mutex, NULL, MUTEX_DRIVER,
1398 	    SBP2_GET_IBLOCK_COOKIE(tp));
1399 	cv_init(&ap->a_cv, NULL, CV_DRIVER, NULL);
1400 
1401 #ifndef __lock_lint
1402 	ap->a_state = SBP2_AGENT_STATE_RESET;
1403 #endif
1404 
1405 	return (SBP2_SUCCESS);
1406 }
1407 
1408 
1409 static void
1410 sbp2_agent_fini(sbp2_agent_t *ap)
1411 {
1412 	sbp2_tgt_t	*tp = ap->a_tgt;
1413 
1414 	/* free bus commands */
1415 	if (ap->a_cmd != NULL) {
1416 		SBP2_FREE_CMD(tp, ap->a_cmd);
1417 	}
1418 	if (ap->a_cmd_data != NULL) {
1419 		freeb(ap->a_cmd_data);
1420 	}
1421 	cv_destroy(&ap->a_cv);
1422 	mutex_destroy(&ap->a_mutex);
1423 }
1424 
1425 
1426 static void
1427 sbp2_agent_acquire_locked(sbp2_agent_t *ap)
1428 {
1429 	while (ap->a_acquired) {
1430 		cv_wait(&ap->a_cv, &ap->a_mutex);
1431 	}
1432 	ap->a_acquired = B_TRUE;
1433 }
1434 
1435 
1436 static void
1437 sbp2_agent_release_locked(sbp2_agent_t *ap)
1438 {
1439 	ap->a_acquired = B_FALSE;
1440 	cv_signal(&ap->a_cv);		/* wake next waiter */
1441 }
1442 
1443 
1444 static void
1445 sbp2_agent_acquire(sbp2_agent_t *ap)
1446 {
1447 	mutex_enter(&ap->a_mutex);
1448 	sbp2_agent_acquire_locked(ap);
1449 	mutex_exit(&ap->a_mutex);
1450 }
1451 
1452 
1453 static void
1454 sbp2_agent_release(sbp2_agent_t *ap)
1455 {
1456 	mutex_enter(&ap->a_mutex);
1457 	sbp2_agent_release_locked(ap);
1458 	mutex_exit(&ap->a_mutex);
1459 }
1460 
1461 
1462 static int
1463 sbp2_agent_keepalive(sbp2_agent_t *ap, int *berr)
1464 {
1465 	boolean_t	acquired;
1466 	int		ret = SBP2_SUCCESS;
1467 
1468 	ASSERT(mutex_owned(&ap->a_mutex));
1469 
1470 	if (ap->a_state == SBP2_AGENT_STATE_DEAD) {
1471 		acquired = ap->a_acquired;
1472 		if (!acquired) {
1473 			sbp2_agent_acquire_locked(ap);
1474 		}
1475 
1476 		mutex_exit(&ap->a_mutex);
1477 		ret = sbp2_agent_reset(ap, berr);
1478 		mutex_enter(&ap->a_mutex);
1479 
1480 		if (!acquired) {
1481 			sbp2_agent_release_locked(ap);
1482 		}
1483 	}
1484 
1485 	return (ret);
1486 }
1487 
1488 #ifndef __lock_lint
1489 static int
1490 sbp2_agent_doorbell(sbp2_agent_t *ap, int *berr)
1491 {
1492 	return (SBP2_WQ(ap->a_tgt, ap->a_cmd, ap->a_reg_doorbell, 0, berr));
1493 }
1494 #endif
1495 
1496 /*
1497  * write into ORB_POINTER register and make sure it reached target
1498  *
1499  * From E.2: "If no acknowledgement is received by the initiator after a write
1500  * 	to the ORB_POINTER register, the initiator should not retry the write.
1501  *	The recommended method for error recovery is a write to the AGENT_RESET
1502  *	register." So we can retry, but not in case of timeout.
1503  */
1504 static int
1505 sbp2_agent_write_orbp(sbp2_agent_t *ap, uint64_t baddr, int *berr)
1506 {
1507 	int		i = 0;
1508 	int		ret;
1509 
1510 	SBP2_ORBP_SET(ap->a_cmd_data->b_rptr, baddr);
1511 	ap->a_cmd_data->b_wptr = ap->a_cmd_data->b_rptr + 8;
1512 
1513 	for (;;) {
1514 		ap->a_tgt->t_stat.stat_agent_worbp++;
1515 		if ((ret = SBP2_WB(ap->a_tgt, ap->a_cmd, ap->a_reg_orbp,
1516 		    ap->a_cmd_data, 8, berr)) == SBP2_SUCCESS) {
1517 			return (ret);
1518 		}
1519 		ap->a_tgt->t_stat.stat_agent_worbp_fail++;
1520 
1521 		if ((ret == SBP2_ETIMEOUT) ||
1522 		    (++i > sbp2_write_orbp_nretries)) {
1523 			break;
1524 		}
1525 		if (sbp2_write_orbp_delay > 0) {
1526 			drv_usecwait(sbp2_write_orbp_delay);
1527 		}
1528 	}
1529 
1530 	return (ret);
1531 }
1532 
1533 
1534 /*
1535  * reset fetch agent by writing into AGENT_RESET register
1536  */
1537 static int
1538 sbp2_agent_reset(sbp2_agent_t *ap, int *berr)
1539 {
1540 	int	i = 0;
1541 	int	ret;
1542 
1543 	for (;;) {
1544 		ap->a_tgt->t_stat.stat_agent_wreset++;
1545 		if ((ret = SBP2_WQ(ap->a_tgt, ap->a_cmd, ap->a_reg_agent_reset,
1546 		    0, berr)) == SBP2_SUCCESS) {
1547 			mutex_enter(&ap->a_mutex);
1548 			ap->a_state = SBP2_AGENT_STATE_RESET;
1549 			mutex_exit(&ap->a_mutex);
1550 			break;
1551 		}
1552 
1553 		ap->a_tgt->t_stat.stat_agent_wreset_fail++;
1554 		if (++i > sbp2_submit_reset_nretries) {
1555 			break;
1556 		}
1557 		if (sbp2_submit_reset_delay > 0) {
1558 			drv_usecwait(sbp2_submit_reset_delay);
1559 		}
1560 	}
1561 	return (ret);
1562 }
1563 
1564 /*
1565  *
1566  * --- callbacks and timeouts
1567  *
1568  */
1569 /*
1570  * Status FIFO callback for mgt ORB's.
1571  */
1572 /*ARGSUSED*/
1573 static void
1574 sbp2_mgt_status_fifo_wb_cb(sbp2_bus_buf_t *buf, void *reqh, mblk_t **bpp)
1575 {
1576 	sbp2_tgt_t	*tp = buf->bb_sbp2_priv;
1577 	int		len;
1578 	sbp2_status_t	*st;
1579 	uint64_t	orbp;
1580 
1581 	len = MBLKL(*bpp);
1582 
1583 	/* 8 bytes minimum */
1584 	if (len < 8) {
1585 		SBP2_BUF_WR_DONE(tp, buf, reqh, SBP2_BUS_BUF_ELENGTH);
1586 		tp->t_stat.stat_status_short++;
1587 		return;
1588 	}
1589 
1590 	/* convert 2-quadlet header from BE to native endianness */
1591 	st = (sbp2_status_t *)(*bpp)->b_rptr;
1592 	SBP2_SWAP16_1(st->st_orb_offset_hi);
1593 	SBP2_SWAP32_1(st->st_orb_offset_lo);
1594 	orbp = ((uint64_t)st->st_orb_offset_hi << 32) | st->st_orb_offset_lo;
1595 
1596 	if (orbp != tp->t_mgt_orb_buf.bb_baddr) {
1597 		SBP2_BUF_WR_DONE(tp, buf, reqh, SBP2_BUS_BUF_FAILURE);
1598 		tp->t_stat.stat_status_mgt_notask++;
1599 		return;
1600 	}
1601 
1602 	/* make a local copy of status block */
1603 	bzero(&tp->t_mgt_status, sizeof (sbp2_status_t));
1604 	bcopy((*bpp)->b_rptr, &tp->t_mgt_status, len);
1605 
1606 	SBP2_BUF_WR_DONE(tp, buf, reqh, SBP2_BUS_BUF_SUCCESS);
1607 
1608 	/* wake up waiter */
1609 	mutex_enter(&tp->t_mutex);
1610 	tp->t_mgt_status_rcvd = B_TRUE;
1611 	cv_signal(&tp->t_mgt_status_cv);
1612 	mutex_exit(&tp->t_mutex);
1613 }
1614 
1615 static void
1616 sbp2_task_timeout(void *arg)
1617 {
1618 	sbp2_task_t	*task = arg;
1619 	sbp2_ses_t	*sp = task->ts_ses;
1620 	sbp2_agent_t	*ap = &sp->s_agent;
1621 
1622 	mutex_enter(&ap->a_mutex);
1623 
1624 	/* cancelled? */
1625 	if (task->ts_timeout_id == 0) {
1626 		mutex_exit(&ap->a_mutex);
1627 		return;
1628 	}
1629 	task->ts_timeout_id = 0;
1630 	task->ts_time_comp = gethrtime();
1631 
1632 	/* avoid race with other callbacks */
1633 	if (task->ts_state != SBP2_TASK_PEND) {
1634 		mutex_exit(&ap->a_mutex);
1635 		return;
1636 	}
1637 
1638 	if (task == ap->a_active_task) {
1639 		ap->a_active_task = NULL;
1640 	}
1641 	task->ts_error = SBP2_TASK_ERR_TIMEOUT;
1642 	task->ts_state = SBP2_TASK_COMP;
1643 
1644 	/* we mark agent DEAD so it's reset before next task is submitted */
1645 	ap->a_state = SBP2_AGENT_STATE_DEAD;
1646 	sp->s_tgt->t_stat.stat_status_dead++;
1647 	mutex_exit(&ap->a_mutex);
1648 
1649 	sp->s_status_cb(sp->s_status_cb_arg, task);
1650 }
1651 
1652 /*
1653  * Status FIFO callback for command ORB's. Also used for login ORB.
1654  */
1655 /*ARGSUSED*/
1656 static void
1657 sbp2_status_fifo_wb_cb(sbp2_bus_buf_t *buf, void *reqh, mblk_t **bpp)
1658 {
1659 	sbp2_ses_t	*sp = buf->bb_sbp2_priv;
1660 	sbp2_tgt_t	*tp = sp->s_tgt;
1661 	sbp2_agent_t	*ap = &sp->s_agent;
1662 	int		len;
1663 	sbp2_status_t	*st;
1664 	uint8_t		src;
1665 	uint64_t	orbp;
1666 	sbp2_task_t	*task;
1667 	timeout_id_t	timeout_id;
1668 
1669 	len = MBLKL(*bpp);
1670 
1671 	/* 8 bytes minimum */
1672 	if (len < 8) {
1673 		SBP2_BUF_WR_DONE(tp, buf, reqh, SBP2_BUS_BUF_ELENGTH);
1674 		tp->t_stat.stat_status_short++;
1675 		return;
1676 	}
1677 
1678 	/* convert 2-quadlet header from BE32 to native endianness */
1679 	st = (sbp2_status_t *)(*bpp)->b_rptr;
1680 	SBP2_SWAP16_1(st->st_orb_offset_hi);
1681 	SBP2_SWAP32_1(st->st_orb_offset_lo);
1682 
1683 	orbp = ((uint64_t)st->st_orb_offset_hi << 32) | st->st_orb_offset_lo;
1684 
1685 	/* login ORB status? */
1686 	if (orbp == tp->t_mgt_orb_buf.bb_baddr) {
1687 		bzero(&tp->t_mgt_status, sizeof (sbp2_status_t));
1688 		bcopy((*bpp)->b_rptr, &tp->t_mgt_status, len);
1689 
1690 		SBP2_BUF_WR_DONE(tp, buf, reqh, SBP2_BUS_BUF_SUCCESS);
1691 
1692 		/* wake up waiter */
1693 		mutex_enter(&tp->t_mutex);
1694 		tp->t_mgt_status_rcvd = B_TRUE;
1695 		cv_signal(&tp->t_mgt_status_cv);
1696 		mutex_exit(&tp->t_mutex);
1697 		return;
1698 	}
1699 
1700 	/* dismiss unsolicited status */
1701 	src = st->st_param & SBP2_ST_SRC;
1702 	if (src == SBP2_ST_SRC_UNSOLICITED) {
1703 		SBP2_BUF_WR_DONE(tp, buf, reqh, SBP2_BUS_BUF_FAILURE);
1704 		tp->t_stat.stat_status_unsolicited++;
1705 		return;
1706 	}
1707 
1708 	/* find task corresponding to this ORB pointer */
1709 	if ((task = sbp2_ses_orbp2task(sp, orbp)) == NULL) {
1710 		SBP2_BUF_WR_DONE(tp, buf, reqh, SBP2_BUS_BUF_FAILURE);
1711 		tp->t_stat.stat_status_notask++;
1712 		return;
1713 	}
1714 
1715 	/*
1716 	 * Copy status block into a local buffer.
1717 	 *
1718 	 * Note: (ref: B.2) "SBP-2 permits the return of a status block between
1719 	 *	two and eight quadlets in length. When a truncated status block
1720 	 *	is stored, the omited quadlets shall be interpreted as if zero
1721 	 *	values were stored."
1722 	 */
1723 	bzero(&task->ts_status, sizeof (sbp2_status_t));
1724 	bcopy((*bpp)->b_rptr, &task->ts_status, len);
1725 
1726 	SBP2_BUF_WR_DONE(tp, buf, reqh, SBP2_BUS_BUF_SUCCESS);
1727 
1728 	mutex_enter(&ap->a_mutex);
1729 
1730 	if ((timeout_id = task->ts_timeout_id) != 0) {
1731 		task->ts_timeout_id = 0;
1732 		(void) untimeout(timeout_id);
1733 	}
1734 
1735 	/* determine agent state */
1736 	if (st->st_param & SBP2_ST_DEAD) {
1737 		ap->a_state = SBP2_AGENT_STATE_DEAD;
1738 		tp->t_stat.stat_status_dead++;
1739 	}
1740 
1741 	/* avoid race with other callbacks */
1742 	if (task->ts_state != SBP2_TASK_PEND) {
1743 		mutex_exit(&ap->a_mutex);
1744 		return;
1745 	}
1746 
1747 	if (task == ap->a_active_task) {
1748 		ap->a_active_task = NULL;
1749 	}
1750 	task->ts_error = SBP2_TASK_ERR_NONE;
1751 	task->ts_state = SBP2_TASK_COMP;
1752 
1753 	mutex_exit(&ap->a_mutex);
1754 
1755 	sp->s_status_cb(sp->s_status_cb_arg, task);	/* notify the driver */
1756 }
1757 
1758 /*
1759  *
1760  * --- other
1761  *
1762  * since mgt agent is shared between LUNs and login sessions,
1763  * it is safer to serialize mgt requests
1764  */
1765 static void
1766 sbp2_mgt_agent_acquire(sbp2_tgt_t *tp)
1767 {
1768 	mutex_enter(&tp->t_mutex);
1769 	while (tp->t_mgt_agent_acquired) {
1770 		cv_wait(&tp->t_mgt_agent_cv, &tp->t_mutex);
1771 	}
1772 	tp->t_mgt_agent_acquired = B_TRUE;
1773 	mutex_exit(&tp->t_mutex);
1774 }
1775 
1776 static void
1777 sbp2_mgt_agent_release(sbp2_tgt_t *tp)
1778 {
1779 	mutex_enter(&tp->t_mutex);
1780 	tp->t_mgt_agent_acquired = B_FALSE;
1781 	cv_signal(&tp->t_mgt_agent_cv);	/* wake next waiter */
1782 	mutex_exit(&tp->t_mutex);
1783 }
1784