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 * Copyright (c) 2009, Intel Corporation.
27 * All Rights Reserved.
28 */
29
30 /*
31 * CPU Device driver. The driver is not DDI-compliant.
32 *
33 * The driver supports following features:
34 * - Power management.
35 */
36
37 #include <sys/types.h>
38 #include <sys/param.h>
39 #include <sys/errno.h>
40 #include <sys/modctl.h>
41 #include <sys/kmem.h>
42 #include <sys/conf.h>
43 #include <sys/cmn_err.h>
44 #include <sys/stat.h>
45 #include <sys/debug.h>
46 #include <sys/systm.h>
47 #include <sys/ddi.h>
48 #include <sys/sunddi.h>
49 #include <sys/sdt.h>
50 #include <sys/epm.h>
51 #include <sys/machsystm.h>
52 #include <sys/x_call.h>
53 #include <sys/cpudrv_mach.h>
54 #include <sys/msacct.h>
55
56 /*
57 * CPU power management
58 *
59 * The supported power saving model is to slow down the CPU (on SPARC by
60 * dividing the CPU clock and on x86 by dropping down a P-state).
61 * Periodically we determine the amount of time the CPU is running
62 * idle thread and threads in user mode during the last quantum. If the idle
63 * thread was running less than its low water mark for current speed for
64 * number of consecutive sampling periods, or number of running threads in
65 * user mode are above its high water mark, we arrange to go to the higher
66 * speed. If the idle thread was running more than its high water mark without
67 * dropping a number of consecutive times below the mark, and number of threads
68 * running in user mode are below its low water mark, we arrange to go to the
69 * next lower speed. While going down, we go through all the speeds. While
70 * going up we go to the maximum speed to minimize impact on the user, but have
71 * provisions in the driver to go to other speeds.
72 *
73 * The driver does not have knowledge of a particular implementation of this
74 * scheme and will work with all CPUs supporting this model. On SPARC, the
75 * driver determines supported speeds by looking at 'clock-divisors' property
76 * created by OBP. On x86, the driver retrieves the supported speeds from
77 * ACPI.
78 */
79
80 /*
81 * Configuration function prototypes and data structures
82 */
83 static int cpudrv_attach(dev_info_t *dip, ddi_attach_cmd_t cmd);
84 static int cpudrv_detach(dev_info_t *dip, ddi_detach_cmd_t cmd);
85 static int cpudrv_power(dev_info_t *dip, int comp, int level);
86
87 struct dev_ops cpudrv_ops = {
88 DEVO_REV, /* rev */
89 0, /* refcnt */
90 nodev, /* getinfo */
91 nulldev, /* identify */
92 nulldev, /* probe */
93 cpudrv_attach, /* attach */
94 cpudrv_detach, /* detach */
95 nodev, /* reset */
96 (struct cb_ops *)NULL, /* cb_ops */
97 (struct bus_ops *)NULL, /* bus_ops */
98 cpudrv_power, /* power */
99 ddi_quiesce_not_needed, /* quiesce */
100 };
101
102 static struct modldrv modldrv = {
103 &mod_driverops, /* modops */
104 "CPU Driver", /* linkinfo */
105 &cpudrv_ops, /* dev_ops */
106 };
107
108 static struct modlinkage modlinkage = {
109 MODREV_1, /* rev */
110 &modldrv, /* linkage */
111 NULL
112 };
113
114 /*
115 * Function prototypes
116 */
117 static int cpudrv_init(cpudrv_devstate_t *cpudsp);
118 static void cpudrv_free(cpudrv_devstate_t *cpudsp);
119 static int cpudrv_comp_create(cpudrv_devstate_t *cpudsp);
120 static void cpudrv_monitor_disp(void *arg);
121 static void cpudrv_monitor(void *arg);
122
123 /*
124 * Driver global variables
125 */
126 uint_t cpudrv_debug = 0;
127 void *cpudrv_state;
128 static uint_t cpudrv_idle_hwm = CPUDRV_IDLE_HWM;
129 static uint_t cpudrv_idle_lwm = CPUDRV_IDLE_LWM;
130 static uint_t cpudrv_idle_buf_zone = CPUDRV_IDLE_BUF_ZONE;
131 static uint_t cpudrv_idle_bhwm_cnt_max = CPUDRV_IDLE_BHWM_CNT_MAX;
132 static uint_t cpudrv_idle_blwm_cnt_max = CPUDRV_IDLE_BLWM_CNT_MAX;
133 static uint_t cpudrv_user_hwm = CPUDRV_USER_HWM;
134
135 boolean_t cpudrv_enabled = B_TRUE;
136
137 /*
138 * cpudrv_direct_pm allows user applications to directly control the
139 * power state transitions (direct pm) without following the normal
140 * direct pm protocol. This is needed because the normal protocol
141 * requires that a device only be lowered when it is idle, and be
142 * brought up when it request to do so by calling pm_raise_power().
143 * Ignoring this protocol is harmless for CPU (other than speed).
144 * Moreover it might be the case that CPU is never idle or wants
145 * to be at higher speed because of the addition CPU cycles required
146 * to run the user application.
147 *
148 * The driver will still report idle/busy status to the framework. Although
149 * framework will ignore this information for direct pm devices and not
150 * try to bring them down when idle, user applications can still use this
151 * information if they wants.
152 *
153 * In the future, provide an ioctl to control setting of this mode. In
154 * that case, this variable should move to the state structure and
155 * be protected by the lock in the state structure.
156 */
157 int cpudrv_direct_pm = 0;
158
159 /*
160 * Arranges for the handler function to be called at the interval suitable
161 * for current speed.
162 */
163 #define CPUDRV_MONITOR_INIT(cpudsp) { \
164 if (cpudrv_is_enabled(cpudsp)) { \
165 ASSERT(mutex_owned(&(cpudsp)->lock)); \
166 (cpudsp)->cpudrv_pm.timeout_id = \
167 timeout(cpudrv_monitor_disp, \
168 (cpudsp), (((cpudsp)->cpudrv_pm.cur_spd == NULL) ? \
169 CPUDRV_QUANT_CNT_OTHR : \
170 (cpudsp)->cpudrv_pm.cur_spd->quant_cnt)); \
171 } \
172 }
173
174 /*
175 * Arranges for the handler function not to be called back.
176 */
177 #define CPUDRV_MONITOR_FINI(cpudsp) { \
178 timeout_id_t tmp_tid; \
179 ASSERT(mutex_owned(&(cpudsp)->lock)); \
180 tmp_tid = (cpudsp)->cpudrv_pm.timeout_id; \
181 (cpudsp)->cpudrv_pm.timeout_id = 0; \
182 mutex_exit(&(cpudsp)->lock); \
183 if (tmp_tid != 0) { \
184 (void) untimeout(tmp_tid); \
185 mutex_enter(&(cpudsp)->cpudrv_pm.timeout_lock); \
186 while ((cpudsp)->cpudrv_pm.timeout_count != 0) \
187 cv_wait(&(cpudsp)->cpudrv_pm.timeout_cv, \
188 &(cpudsp)->cpudrv_pm.timeout_lock); \
189 mutex_exit(&(cpudsp)->cpudrv_pm.timeout_lock); \
190 } \
191 mutex_enter(&(cpudsp)->lock); \
192 }
193
194 int
195 _init(void)
196 {
197 int error;
198
199 DPRINTF(D_INIT, (" _init: function called\n"));
200 if ((error = ddi_soft_state_init(&cpudrv_state,
201 sizeof (cpudrv_devstate_t), 0)) != 0) {
202 return (error);
203 }
204
205 if ((error = mod_install(&modlinkage)) != 0) {
206 ddi_soft_state_fini(&cpudrv_state);
207 }
208
209 /*
210 * Callbacks used by the PPM driver.
211 */
212 CPUDRV_SET_PPM_CALLBACKS();
213 return (error);
214 }
215
216 int
217 _fini(void)
218 {
219 int error;
220
221 DPRINTF(D_FINI, (" _fini: function called\n"));
222 if ((error = mod_remove(&modlinkage)) == 0) {
223 ddi_soft_state_fini(&cpudrv_state);
224 }
225
226 return (error);
227 }
228
229 int
230 _info(struct modinfo *modinfop)
231 {
232 return (mod_info(&modlinkage, modinfop));
233 }
234
235 /*
236 * Driver attach(9e) entry point.
237 */
238 static int
239 cpudrv_attach(dev_info_t *dip, ddi_attach_cmd_t cmd)
240 {
241 int instance;
242 cpudrv_devstate_t *cpudsp;
243
244 instance = ddi_get_instance(dip);
245
246 switch (cmd) {
247 case DDI_ATTACH:
248 DPRINTF(D_ATTACH, ("cpudrv_attach: instance %d: "
249 "DDI_ATTACH called\n", instance));
250 if (!cpudrv_is_enabled(NULL))
251 return (DDI_FAILURE);
252 if (ddi_soft_state_zalloc(cpudrv_state, instance) !=
253 DDI_SUCCESS) {
254 cmn_err(CE_WARN, "cpudrv_attach: instance %d: "
255 "can't allocate state", instance);
256 cpudrv_enabled = B_FALSE;
257 return (DDI_FAILURE);
258 }
259 if ((cpudsp = ddi_get_soft_state(cpudrv_state, instance)) ==
260 NULL) {
261 cmn_err(CE_WARN, "cpudrv_attach: instance %d: "
262 "can't get state", instance);
263 ddi_soft_state_free(cpudrv_state, instance);
264 cpudrv_enabled = B_FALSE;
265 return (DDI_FAILURE);
266 }
267 cpudsp->dip = dip;
268
269 /*
270 * Find CPU number for this dev_info node.
271 */
272 if (!cpudrv_get_cpu_id(dip, &(cpudsp->cpu_id))) {
273 cmn_err(CE_WARN, "cpudrv_attach: instance %d: "
274 "can't convert dip to cpu_id", instance);
275 ddi_soft_state_free(cpudrv_state, instance);
276 cpudrv_enabled = B_FALSE;
277 return (DDI_FAILURE);
278 }
279
280 mutex_init(&cpudsp->lock, NULL, MUTEX_DRIVER, NULL);
281 if (cpudrv_is_enabled(cpudsp)) {
282 if (cpudrv_init(cpudsp) != DDI_SUCCESS) {
283 cpudrv_enabled = B_FALSE;
284 cpudrv_free(cpudsp);
285 ddi_soft_state_free(cpudrv_state, instance);
286 return (DDI_FAILURE);
287 }
288 if (cpudrv_comp_create(cpudsp) != DDI_SUCCESS) {
289 cpudrv_enabled = B_FALSE;
290 cpudrv_free(cpudsp);
291 ddi_soft_state_free(cpudrv_state, instance);
292 return (DDI_FAILURE);
293 }
294 if (ddi_prop_update_string(DDI_DEV_T_NONE,
295 dip, "pm-class", "CPU") != DDI_PROP_SUCCESS) {
296 cpudrv_enabled = B_FALSE;
297 cpudrv_free(cpudsp);
298 ddi_soft_state_free(cpudrv_state, instance);
299 return (DDI_FAILURE);
300 }
301
302 /*
303 * Taskq is used to dispatch routine to monitor CPU
304 * activities.
305 */
306 cpudsp->cpudrv_pm.tq = ddi_taskq_create(dip,
307 "cpudrv_monitor", CPUDRV_TASKQ_THREADS,
308 TASKQ_DEFAULTPRI, 0);
309
310 mutex_init(&cpudsp->cpudrv_pm.timeout_lock, NULL,
311 MUTEX_DRIVER, NULL);
312 cv_init(&cpudsp->cpudrv_pm.timeout_cv, NULL,
313 CV_DEFAULT, NULL);
314
315 /*
316 * Driver needs to assume that CPU is running at
317 * unknown speed at DDI_ATTACH and switch it to the
318 * needed speed. We assume that initial needed speed
319 * is full speed for us.
320 */
321 /*
322 * We need to take the lock because cpudrv_monitor()
323 * will start running in parallel with attach().
324 */
325 mutex_enter(&cpudsp->lock);
326 cpudsp->cpudrv_pm.cur_spd = NULL;
327 cpudsp->cpudrv_pm.pm_started = B_FALSE;
328 /*
329 * We don't call pm_raise_power() directly from attach
330 * because driver attach for a slave CPU node can
331 * happen before the CPU is even initialized. We just
332 * start the monitoring system which understands
333 * unknown speed and moves CPU to top speed when it
334 * has been initialized.
335 */
336 CPUDRV_MONITOR_INIT(cpudsp);
337 mutex_exit(&cpudsp->lock);
338
339 }
340
341 if (!cpudrv_mach_init(cpudsp)) {
342 cmn_err(CE_WARN, "cpudrv_attach: instance %d: "
343 "cpudrv_mach_init failed", instance);
344 cpudrv_enabled = B_FALSE;
345 cpudrv_free(cpudsp);
346 ddi_soft_state_free(cpudrv_state, instance);
347 return (DDI_FAILURE);
348 }
349
350 CPUDRV_INSTALL_MAX_CHANGE_HANDLER(cpudsp);
351
352 (void) ddi_prop_update_int(DDI_DEV_T_NONE, dip,
353 DDI_NO_AUTODETACH, 1);
354 ddi_report_dev(dip);
355 return (DDI_SUCCESS);
356
357 case DDI_RESUME:
358 DPRINTF(D_ATTACH, ("cpudrv_attach: instance %d: "
359 "DDI_RESUME called\n", instance));
360
361 cpudsp = ddi_get_soft_state(cpudrv_state, instance);
362 ASSERT(cpudsp != NULL);
363
364 /*
365 * Nothing to do for resume, if not doing active PM.
366 */
367 if (!cpudrv_is_enabled(cpudsp))
368 return (DDI_SUCCESS);
369
370 mutex_enter(&cpudsp->lock);
371 /*
372 * Driver needs to assume that CPU is running at unknown speed
373 * at DDI_RESUME and switch it to the needed speed. We assume
374 * that the needed speed is full speed for us.
375 */
376 cpudsp->cpudrv_pm.cur_spd = NULL;
377 CPUDRV_MONITOR_INIT(cpudsp);
378 mutex_exit(&cpudsp->lock);
379 CPUDRV_REDEFINE_TOPSPEED(dip);
380 return (DDI_SUCCESS);
381
382 default:
383 return (DDI_FAILURE);
384 }
385 }
386
387 /*
388 * Driver detach(9e) entry point.
389 */
390 static int
391 cpudrv_detach(dev_info_t *dip, ddi_detach_cmd_t cmd)
392 {
393 int instance;
394 cpudrv_devstate_t *cpudsp;
395 cpudrv_pm_t *cpupm;
396
397 instance = ddi_get_instance(dip);
398
399 switch (cmd) {
400 case DDI_DETACH:
401 DPRINTF(D_DETACH, ("cpudrv_detach: instance %d: "
402 "DDI_DETACH called\n", instance));
403
404 #if defined(__x86)
405 cpudsp = ddi_get_soft_state(cpudrv_state, instance);
406 ASSERT(cpudsp != NULL);
407
408 /*
409 * Nothing to do for detach, if no doing active PM.
410 */
411 if (!cpudrv_is_enabled(cpudsp))
412 return (DDI_SUCCESS);
413
414 /*
415 * uninstall PPC/_TPC change notification handler
416 */
417 CPUDRV_UNINSTALL_MAX_CHANGE_HANDLER(cpudsp);
418
419 /*
420 * destruct platform specific resource
421 */
422 if (!cpudrv_mach_fini(cpudsp))
423 return (DDI_FAILURE);
424
425 mutex_enter(&cpudsp->lock);
426 CPUDRV_MONITOR_FINI(cpudsp);
427 cv_destroy(&cpudsp->cpudrv_pm.timeout_cv);
428 mutex_destroy(&cpudsp->cpudrv_pm.timeout_lock);
429 ddi_taskq_destroy(cpudsp->cpudrv_pm.tq);
430 cpudrv_free(cpudsp);
431 mutex_exit(&cpudsp->lock);
432 mutex_destroy(&cpudsp->lock);
433 ddi_soft_state_free(cpudrv_state, instance);
434 (void) ddi_prop_update_int(DDI_DEV_T_NONE, dip,
435 DDI_NO_AUTODETACH, 0);
436 return (DDI_SUCCESS);
437
438 #else
439 /*
440 * If the only thing supported by the driver is power
441 * management, we can in future enhance the driver and
442 * framework that loads it to unload the driver when
443 * user has disabled CPU power management.
444 */
445 return (DDI_FAILURE);
446 #endif
447
448 case DDI_SUSPEND:
449 DPRINTF(D_DETACH, ("cpudrv_detach: instance %d: "
450 "DDI_SUSPEND called\n", instance));
451
452 cpudsp = ddi_get_soft_state(cpudrv_state, instance);
453 ASSERT(cpudsp != NULL);
454
455 /*
456 * Nothing to do for suspend, if not doing active PM.
457 */
458 if (!cpudrv_is_enabled(cpudsp))
459 return (DDI_SUCCESS);
460
461 /*
462 * During a checkpoint-resume sequence, framework will
463 * stop interrupts to quiesce kernel activity. This will
464 * leave our monitoring system ineffective. Handle this
465 * by stopping our monitoring system and bringing CPU
466 * to full speed. In case we are in special direct pm
467 * mode, we leave the CPU at whatever speed it is. This
468 * is harmless other than speed.
469 */
470 mutex_enter(&cpudsp->lock);
471 cpupm = &(cpudsp->cpudrv_pm);
472
473 DPRINTF(D_DETACH, ("cpudrv_detach: instance %d: DDI_SUSPEND - "
474 "cur_spd %d, topspeed %d\n", instance,
475 cpupm->cur_spd->pm_level,
476 CPUDRV_TOPSPEED(cpupm)->pm_level));
477
478 CPUDRV_MONITOR_FINI(cpudsp);
479
480 if (!cpudrv_direct_pm && (cpupm->cur_spd !=
481 CPUDRV_TOPSPEED(cpupm))) {
482 if (cpupm->pm_busycnt < 1) {
483 if ((pm_busy_component(dip, CPUDRV_COMP_NUM)
484 == DDI_SUCCESS)) {
485 cpupm->pm_busycnt++;
486 } else {
487 CPUDRV_MONITOR_INIT(cpudsp);
488 mutex_exit(&cpudsp->lock);
489 cmn_err(CE_WARN, "cpudrv_detach: "
490 "instance %d: can't busy CPU "
491 "component", instance);
492 return (DDI_FAILURE);
493 }
494 }
495 mutex_exit(&cpudsp->lock);
496 if (pm_raise_power(dip, CPUDRV_COMP_NUM,
497 CPUDRV_TOPSPEED(cpupm)->pm_level) !=
498 DDI_SUCCESS) {
499 mutex_enter(&cpudsp->lock);
500 CPUDRV_MONITOR_INIT(cpudsp);
501 mutex_exit(&cpudsp->lock);
502 cmn_err(CE_WARN, "cpudrv_detach: instance %d: "
503 "can't raise CPU power level to %d",
504 instance,
505 CPUDRV_TOPSPEED(cpupm)->pm_level);
506 return (DDI_FAILURE);
507 } else {
508 return (DDI_SUCCESS);
509 }
510 } else {
511 mutex_exit(&cpudsp->lock);
512 return (DDI_SUCCESS);
513 }
514
515 default:
516 return (DDI_FAILURE);
517 }
518 }
519
520 /*
521 * Driver power(9e) entry point.
522 *
523 * Driver's notion of current power is set *only* in power(9e) entry point
524 * after actual power change operation has been successfully completed.
525 */
526 /* ARGSUSED */
527 static int
528 cpudrv_power(dev_info_t *dip, int comp, int level)
529 {
530 int instance;
531 cpudrv_devstate_t *cpudsp;
532 cpudrv_pm_t *cpudrvpm;
533 cpudrv_pm_spd_t *new_spd;
534 boolean_t is_ready;
535 int ret;
536
537 instance = ddi_get_instance(dip);
538
539 DPRINTF(D_POWER, ("cpudrv_power: instance %d: level %d\n",
540 instance, level));
541
542 if ((cpudsp = ddi_get_soft_state(cpudrv_state, instance)) == NULL) {
543 cmn_err(CE_WARN, "cpudrv_power: instance %d: can't "
544 "get state", instance);
545 return (DDI_FAILURE);
546 }
547
548 /*
549 * We're not ready until we can get a cpu_t
550 */
551 is_ready = (cpudrv_get_cpu(cpudsp) == DDI_SUCCESS);
552
553 mutex_enter(&cpudsp->lock);
554 cpudrvpm = &(cpudsp->cpudrv_pm);
555
556 /*
557 * In normal operation, we fail if we are busy and request is
558 * to lower the power level. We let this go through if the driver
559 * is in special direct pm mode. On x86, we also let this through
560 * if the change is due to a request to govern the max speed.
561 */
562 if (!cpudrv_direct_pm && (cpudrvpm->pm_busycnt >= 1) &&
563 !cpudrv_is_governor_thread(cpudrvpm)) {
564 if ((cpudrvpm->cur_spd != NULL) &&
565 (level < cpudrvpm->cur_spd->pm_level)) {
566 mutex_exit(&cpudsp->lock);
567 return (DDI_FAILURE);
568 }
569 }
570
571 for (new_spd = cpudrvpm->head_spd; new_spd; new_spd =
572 new_spd->down_spd) {
573 if (new_spd->pm_level == level)
574 break;
575 }
576 if (!new_spd) {
577 CPUDRV_RESET_GOVERNOR_THREAD(cpudrvpm);
578 mutex_exit(&cpudsp->lock);
579 cmn_err(CE_WARN, "cpudrv_power: instance %d: "
580 "can't locate new CPU speed", instance);
581 return (DDI_FAILURE);
582 }
583
584 /*
585 * We currently refuse to power manage if the CPU is not ready to
586 * take cross calls (cross calls fail silently if CPU is not ready
587 * for it).
588 *
589 * Additionally, for x86 platforms we cannot power manage an instance,
590 * until it has been initialized.
591 */
592 if (is_ready) {
593 is_ready = CPUDRV_XCALL_IS_READY(cpudsp->cpu_id);
594 if (!is_ready) {
595 DPRINTF(D_POWER, ("cpudrv_power: instance %d: "
596 "CPU not ready for x-calls\n", instance));
597 } else if (!(is_ready = cpudrv_power_ready(cpudsp->cp))) {
598 DPRINTF(D_POWER, ("cpudrv_power: instance %d: "
599 "waiting for all CPUs to be power manageable\n",
600 instance));
601 }
602 }
603 if (!is_ready) {
604 CPUDRV_RESET_GOVERNOR_THREAD(cpudrvpm);
605 mutex_exit(&cpudsp->lock);
606 return (DDI_FAILURE);
607 }
608
609 /*
610 * Execute CPU specific routine on the requested CPU to
611 * change its speed to normal-speed/divisor.
612 */
613 if ((ret = cpudrv_change_speed(cpudsp, new_spd)) != DDI_SUCCESS) {
614 cmn_err(CE_WARN, "cpudrv_power: "
615 "cpudrv_change_speed() return = %d", ret);
616 mutex_exit(&cpudsp->lock);
617 return (DDI_FAILURE);
618 }
619
620 /*
621 * Reset idle threshold time for the new power level.
622 */
623 if ((cpudrvpm->cur_spd != NULL) && (level <
624 cpudrvpm->cur_spd->pm_level)) {
625 if (pm_idle_component(dip, CPUDRV_COMP_NUM) ==
626 DDI_SUCCESS) {
627 if (cpudrvpm->pm_busycnt >= 1)
628 cpudrvpm->pm_busycnt--;
629 } else {
630 cmn_err(CE_WARN, "cpudrv_power: instance %d: "
631 "can't idle CPU component",
632 ddi_get_instance(dip));
633 }
634 }
635 /*
636 * Reset various parameters because we are now running at new speed.
637 */
638 cpudrvpm->lastquan_mstate[CMS_IDLE] = 0;
639 cpudrvpm->lastquan_mstate[CMS_SYSTEM] = 0;
640 cpudrvpm->lastquan_mstate[CMS_USER] = 0;
641 cpudrvpm->lastquan_ticks = 0;
642 cpudrvpm->cur_spd = new_spd;
643 CPUDRV_RESET_GOVERNOR_THREAD(cpudrvpm);
644 mutex_exit(&cpudsp->lock);
645
646 return (DDI_SUCCESS);
647 }
648
649 /*
650 * Initialize power management data.
651 */
652 static int
653 cpudrv_init(cpudrv_devstate_t *cpudsp)
654 {
655 cpudrv_pm_t *cpupm = &(cpudsp->cpudrv_pm);
656 cpudrv_pm_spd_t *cur_spd;
657 cpudrv_pm_spd_t *prev_spd = NULL;
658 int *speeds;
659 uint_t nspeeds;
660 int idle_cnt_percent;
661 int user_cnt_percent;
662 int i;
663
664 CPUDRV_GET_SPEEDS(cpudsp, speeds, nspeeds);
665 if (nspeeds < 2) {
666 /* Need at least two speeds to power manage */
667 CPUDRV_FREE_SPEEDS(speeds, nspeeds);
668 return (DDI_FAILURE);
669 }
670 cpupm->num_spd = nspeeds;
671
672 /*
673 * Calculate the watermarks and other parameters based on the
674 * supplied speeds.
675 *
676 * One of the basic assumption is that for X amount of CPU work,
677 * if CPU is slowed down by a factor of N, the time it takes to
678 * do the same work will be N * X.
679 *
680 * The driver declares that a CPU is idle and ready for slowed down,
681 * if amount of idle thread is more than the current speed idle_hwm
682 * without dropping below idle_hwm a number of consecutive sampling
683 * intervals and number of running threads in user mode are below
684 * user_lwm. We want to set the current user_lwm such that if we
685 * just switched to the next slower speed with no change in real work
686 * load, the amount of user threads at the slower speed will be such
687 * that it falls below the slower speed's user_hwm. If we didn't do
688 * that then we will just come back to the higher speed as soon as we
689 * go down even with no change in work load.
690 * The user_hwm is a fixed precentage and not calculated dynamically.
691 *
692 * We bring the CPU up if idle thread at current speed is less than
693 * the current speed idle_lwm for a number of consecutive sampling
694 * intervals or user threads are above the user_hwm for the current
695 * speed.
696 */
697 for (i = 0; i < nspeeds; i++) {
698 cur_spd = kmem_zalloc(sizeof (cpudrv_pm_spd_t), KM_SLEEP);
699 cur_spd->speed = speeds[i];
700 if (i == 0) { /* normal speed */
701 cpupm->head_spd = cur_spd;
702 CPUDRV_TOPSPEED(cpupm) = cur_spd;
703 cur_spd->quant_cnt = CPUDRV_QUANT_CNT_NORMAL;
704 cur_spd->idle_hwm =
705 (cpudrv_idle_hwm * cur_spd->quant_cnt) / 100;
706 /* can't speed anymore */
707 cur_spd->idle_lwm = 0;
708 cur_spd->user_hwm = UINT_MAX;
709 } else {
710 cur_spd->quant_cnt = CPUDRV_QUANT_CNT_OTHR;
711 ASSERT(prev_spd != NULL);
712 prev_spd->down_spd = cur_spd;
713 cur_spd->up_spd = cpupm->head_spd;
714
715 /*
716 * Let's assume CPU is considered idle at full speed
717 * when it is spending I% of time in running the idle
718 * thread. At full speed, CPU will be busy (100 - I) %
719 * of times. This % of busyness increases by factor of
720 * N as CPU slows down. CPU that is idle I% of times
721 * in full speed, it is idle (100 - ((100 - I) * N)) %
722 * of times in N speed. The idle_lwm is a fixed
723 * percentage. A large value of N may result in
724 * idle_hwm to go below idle_lwm. We need to make sure
725 * that there is at least a buffer zone seperation
726 * between the idle_lwm and idle_hwm values.
727 */
728 idle_cnt_percent = CPUDRV_IDLE_CNT_PERCENT(
729 cpudrv_idle_hwm, speeds, i);
730 idle_cnt_percent = max(idle_cnt_percent,
731 (cpudrv_idle_lwm + cpudrv_idle_buf_zone));
732 cur_spd->idle_hwm =
733 (idle_cnt_percent * cur_spd->quant_cnt) / 100;
734 cur_spd->idle_lwm =
735 (cpudrv_idle_lwm * cur_spd->quant_cnt) / 100;
736
737 /*
738 * The lwm for user threads are determined such that
739 * if CPU slows down, the load of work in the
740 * new speed would still keep the CPU at or below the
741 * user_hwm in the new speed. This is to prevent
742 * the quick jump back up to higher speed.
743 */
744 cur_spd->user_hwm = (cpudrv_user_hwm *
745 cur_spd->quant_cnt) / 100;
746 user_cnt_percent = CPUDRV_USER_CNT_PERCENT(
747 cpudrv_user_hwm, speeds, i);
748 prev_spd->user_lwm =
749 (user_cnt_percent * prev_spd->quant_cnt) / 100;
750 }
751 prev_spd = cur_spd;
752 }
753 /* Slowest speed. Can't slow down anymore */
754 cur_spd->idle_hwm = UINT_MAX;
755 cur_spd->user_lwm = -1;
756 #ifdef DEBUG
757 DPRINTF(D_PM_INIT, ("cpudrv_init: instance %d: head_spd spd %d, "
758 "num_spd %d\n", ddi_get_instance(cpudsp->dip),
759 cpupm->head_spd->speed, cpupm->num_spd));
760 for (cur_spd = cpupm->head_spd; cur_spd; cur_spd = cur_spd->down_spd) {
761 DPRINTF(D_PM_INIT, ("cpudrv_init: instance %d: speed %d, "
762 "down_spd spd %d, idle_hwm %d, user_lwm %d, "
763 "up_spd spd %d, idle_lwm %d, user_hwm %d, "
764 "quant_cnt %d\n", ddi_get_instance(cpudsp->dip),
765 cur_spd->speed,
766 (cur_spd->down_spd ? cur_spd->down_spd->speed : 0),
767 cur_spd->idle_hwm, cur_spd->user_lwm,
768 (cur_spd->up_spd ? cur_spd->up_spd->speed : 0),
769 cur_spd->idle_lwm, cur_spd->user_hwm,
770 cur_spd->quant_cnt));
771 }
772 #endif /* DEBUG */
773 CPUDRV_FREE_SPEEDS(speeds, nspeeds);
774 return (DDI_SUCCESS);
775 }
776
777 /*
778 * Free CPU power management data.
779 */
780 static void
781 cpudrv_free(cpudrv_devstate_t *cpudsp)
782 {
783 cpudrv_pm_t *cpupm = &(cpudsp->cpudrv_pm);
784 cpudrv_pm_spd_t *cur_spd, *next_spd;
785
786 cur_spd = cpupm->head_spd;
787 while (cur_spd) {
788 next_spd = cur_spd->down_spd;
789 kmem_free(cur_spd, sizeof (cpudrv_pm_spd_t));
790 cur_spd = next_spd;
791 }
792 bzero(cpupm, sizeof (cpudrv_pm_t));
793 }
794
795 /*
796 * Create pm-components property.
797 */
798 static int
799 cpudrv_comp_create(cpudrv_devstate_t *cpudsp)
800 {
801 cpudrv_pm_t *cpupm = &(cpudsp->cpudrv_pm);
802 cpudrv_pm_spd_t *cur_spd;
803 char **pmc;
804 int size;
805 char name[] = "NAME=CPU Speed";
806 int i, j;
807 uint_t comp_spd;
808 int result = DDI_FAILURE;
809
810 pmc = kmem_zalloc((cpupm->num_spd + 1) * sizeof (char *), KM_SLEEP);
811 size = CPUDRV_COMP_SIZE();
812 if (cpupm->num_spd > CPUDRV_COMP_MAX_VAL) {
813 cmn_err(CE_WARN, "cpudrv_comp_create: instance %d: "
814 "number of speeds exceeded limits",
815 ddi_get_instance(cpudsp->dip));
816 kmem_free(pmc, (cpupm->num_spd + 1) * sizeof (char *));
817 return (result);
818 }
819
820 for (i = cpupm->num_spd, cur_spd = cpupm->head_spd; i > 0;
821 i--, cur_spd = cur_spd->down_spd) {
822 cur_spd->pm_level = i;
823 pmc[i] = kmem_zalloc((size * sizeof (char)), KM_SLEEP);
824 comp_spd = CPUDRV_COMP_SPEED(cpupm, cur_spd);
825 if (comp_spd > CPUDRV_COMP_MAX_VAL) {
826 cmn_err(CE_WARN, "cpudrv_comp_create: "
827 "instance %d: speed exceeded limits",
828 ddi_get_instance(cpudsp->dip));
829 for (j = cpupm->num_spd; j >= i; j--) {
830 kmem_free(pmc[j], size * sizeof (char));
831 }
832 kmem_free(pmc, (cpupm->num_spd + 1) *
833 sizeof (char *));
834 return (result);
835 }
836 CPUDRV_COMP_SPRINT(pmc[i], cpupm, cur_spd, comp_spd)
837 DPRINTF(D_PM_COMP_CREATE, ("cpudrv_comp_create: "
838 "instance %d: pm-components power level %d string '%s'\n",
839 ddi_get_instance(cpudsp->dip), i, pmc[i]));
840 }
841 pmc[0] = kmem_zalloc(sizeof (name), KM_SLEEP);
842 (void) strcat(pmc[0], name);
843 DPRINTF(D_PM_COMP_CREATE, ("cpudrv_comp_create: instance %d: "
844 "pm-components component name '%s'\n",
845 ddi_get_instance(cpudsp->dip), pmc[0]));
846
847 if (ddi_prop_update_string_array(DDI_DEV_T_NONE, cpudsp->dip,
848 "pm-components", pmc, cpupm->num_spd + 1) == DDI_PROP_SUCCESS) {
849 result = DDI_SUCCESS;
850 } else {
851 cmn_err(CE_WARN, "cpudrv_comp_create: instance %d: "
852 "can't create pm-components property",
853 ddi_get_instance(cpudsp->dip));
854 }
855
856 for (i = cpupm->num_spd; i > 0; i--) {
857 kmem_free(pmc[i], size * sizeof (char));
858 }
859 kmem_free(pmc[0], sizeof (name));
860 kmem_free(pmc, (cpupm->num_spd + 1) * sizeof (char *));
861 return (result);
862 }
863
864 /*
865 * Mark a component idle.
866 */
867 #define CPUDRV_MONITOR_PM_IDLE_COMP(dip, cpupm) { \
868 if ((cpupm)->pm_busycnt >= 1) { \
869 if (pm_idle_component((dip), CPUDRV_COMP_NUM) == \
870 DDI_SUCCESS) { \
871 DPRINTF(D_PM_MONITOR, ("cpudrv_monitor: " \
872 "instance %d: pm_idle_component called\n", \
873 ddi_get_instance((dip)))); \
874 (cpupm)->pm_busycnt--; \
875 } else { \
876 cmn_err(CE_WARN, "cpudrv_monitor: instance %d: " \
877 "can't idle CPU component", \
878 ddi_get_instance((dip))); \
879 } \
880 } \
881 }
882
883 /*
884 * Marks a component busy in both PM framework and driver state structure.
885 */
886 #define CPUDRV_MONITOR_PM_BUSY_COMP(dip, cpupm) { \
887 if ((cpupm)->pm_busycnt < 1) { \
888 if (pm_busy_component((dip), CPUDRV_COMP_NUM) == \
889 DDI_SUCCESS) { \
890 DPRINTF(D_PM_MONITOR, ("cpudrv_monitor: " \
891 "instance %d: pm_busy_component called\n", \
892 ddi_get_instance((dip)))); \
893 (cpupm)->pm_busycnt++; \
894 } else { \
895 cmn_err(CE_WARN, "cpudrv_monitor: instance %d: " \
896 "can't busy CPU component", \
897 ddi_get_instance((dip))); \
898 } \
899 } \
900 }
901
902 /*
903 * Marks a component busy and calls pm_raise_power().
904 */
905 #define CPUDRV_MONITOR_PM_BUSY_AND_RAISE(dip, cpudsp, cpupm, new_spd) { \
906 int ret; \
907 /* \
908 * Mark driver and PM framework busy first so framework doesn't try \
909 * to bring CPU to lower speed when we need to be at higher speed. \
910 */ \
911 CPUDRV_MONITOR_PM_BUSY_COMP((dip), (cpupm)); \
912 mutex_exit(&(cpudsp)->lock); \
913 DPRINTF(D_PM_MONITOR, ("cpudrv_monitor: instance %d: " \
914 "pm_raise_power called to %d\n", ddi_get_instance((dip)), \
915 (new_spd->pm_level))); \
916 ret = pm_raise_power((dip), CPUDRV_COMP_NUM, (new_spd->pm_level)); \
917 if (ret != DDI_SUCCESS) { \
918 cmn_err(CE_WARN, "cpudrv_monitor: instance %d: can't " \
919 "raise CPU power level", ddi_get_instance((dip))); \
920 } \
921 mutex_enter(&(cpudsp)->lock); \
922 if (ret == DDI_SUCCESS && cpudsp->cpudrv_pm.cur_spd == NULL) { \
923 cpudsp->cpudrv_pm.cur_spd = new_spd; \
924 } \
925 }
926
927 /*
928 * In order to monitor a CPU, we need to hold cpu_lock to access CPU
929 * statistics. Holding cpu_lock is not allowed from a callout routine.
930 * We dispatch a taskq to do that job.
931 */
932 static void
933 cpudrv_monitor_disp(void *arg)
934 {
935 cpudrv_devstate_t *cpudsp = (cpudrv_devstate_t *)arg;
936
937 /*
938 * We are here because the last task has scheduled a timeout.
939 * The queue should be empty at this time.
940 */
941 mutex_enter(&cpudsp->cpudrv_pm.timeout_lock);
942 if ((ddi_taskq_dispatch(cpudsp->cpudrv_pm.tq, cpudrv_monitor, arg,
943 DDI_NOSLEEP)) != DDI_SUCCESS) {
944 mutex_exit(&cpudsp->cpudrv_pm.timeout_lock);
945 DPRINTF(D_PM_MONITOR, ("cpudrv_monitor_disp: failed to "
946 "dispatch the cpudrv_monitor taskq\n"));
947 mutex_enter(&cpudsp->lock);
948 CPUDRV_MONITOR_INIT(cpudsp);
949 mutex_exit(&cpudsp->lock);
950 return;
951 }
952 cpudsp->cpudrv_pm.timeout_count++;
953 mutex_exit(&cpudsp->cpudrv_pm.timeout_lock);
954 }
955
956 /*
957 * Monitors each CPU for the amount of time idle thread was running in the
958 * last quantum and arranges for the CPU to go to the lower or higher speed.
959 * Called at the time interval appropriate for the current speed. The
960 * time interval for normal speed is CPUDRV_QUANT_CNT_NORMAL. The time
961 * interval for other speeds (including unknown speed) is
962 * CPUDRV_QUANT_CNT_OTHR.
963 */
964 static void
965 cpudrv_monitor(void *arg)
966 {
967 cpudrv_devstate_t *cpudsp = (cpudrv_devstate_t *)arg;
968 cpudrv_pm_t *cpupm;
969 cpudrv_pm_spd_t *cur_spd, *new_spd;
970 dev_info_t *dip;
971 uint_t idle_cnt, user_cnt, system_cnt;
972 clock_t ticks;
973 uint_t tick_cnt;
974 hrtime_t msnsecs[NCMSTATES];
975 boolean_t is_ready;
976
977 #define GET_CPU_MSTATE_CNT(state, cnt) \
978 msnsecs[state] = NSEC_TO_TICK(msnsecs[state]); \
979 if (cpupm->lastquan_mstate[state] > msnsecs[state]) \
980 msnsecs[state] = cpupm->lastquan_mstate[state]; \
981 cnt = msnsecs[state] - cpupm->lastquan_mstate[state]; \
982 cpupm->lastquan_mstate[state] = msnsecs[state]
983
984 /*
985 * We're not ready until we can get a cpu_t
986 */
987 is_ready = (cpudrv_get_cpu(cpudsp) == DDI_SUCCESS);
988
989 mutex_enter(&cpudsp->lock);
990 cpupm = &(cpudsp->cpudrv_pm);
991 if (cpupm->timeout_id == 0) {
992 mutex_exit(&cpudsp->lock);
993 goto do_return;
994 }
995 cur_spd = cpupm->cur_spd;
996 dip = cpudsp->dip;
997
998 /*
999 * We assume that a CPU is initialized and has a valid cpu_t
1000 * structure, if it is ready for cross calls. If this changes,
1001 * additional checks might be needed.
1002 *
1003 * Additionally, for x86 platforms we cannot power manage an
1004 * instance, until it has been initialized.
1005 */
1006 if (is_ready) {
1007 is_ready = CPUDRV_XCALL_IS_READY(cpudsp->cpu_id);
1008 if (!is_ready) {
1009 DPRINTF(D_PM_MONITOR, ("cpudrv_monitor: instance %d: "
1010 "CPU not ready for x-calls\n",
1011 ddi_get_instance(dip)));
1012 } else if (!(is_ready = cpudrv_power_ready(cpudsp->cp))) {
1013 DPRINTF(D_PM_MONITOR, ("cpudrv_monitor: instance %d: "
1014 "waiting for all CPUs to be power manageable\n",
1015 ddi_get_instance(dip)));
1016 }
1017 }
1018 if (!is_ready) {
1019 /*
1020 * Make sure that we are busy so that framework doesn't
1021 * try to bring us down in this situation.
1022 */
1023 CPUDRV_MONITOR_PM_BUSY_COMP(dip, cpupm);
1024 CPUDRV_MONITOR_INIT(cpudsp);
1025 mutex_exit(&cpudsp->lock);
1026 goto do_return;
1027 }
1028
1029 /*
1030 * Make sure that we are still not at unknown power level.
1031 */
1032 if (cur_spd == NULL) {
1033 DPRINTF(D_PM_MONITOR, ("cpudrv_monitor: instance %d: "
1034 "cur_spd is unknown\n", ddi_get_instance(dip)));
1035 CPUDRV_MONITOR_PM_BUSY_AND_RAISE(dip, cpudsp, cpupm,
1036 CPUDRV_TOPSPEED(cpupm));
1037 /*
1038 * We just changed the speed. Wait till at least next
1039 * call to this routine before proceeding ahead.
1040 */
1041 CPUDRV_MONITOR_INIT(cpudsp);
1042 mutex_exit(&cpudsp->lock);
1043 goto do_return;
1044 }
1045
1046 if (!cpupm->pm_started) {
1047 cpupm->pm_started = B_TRUE;
1048 cpudrv_set_supp_freqs(cpudsp);
1049 }
1050
1051 get_cpu_mstate(cpudsp->cp, msnsecs);
1052 GET_CPU_MSTATE_CNT(CMS_IDLE, idle_cnt);
1053 GET_CPU_MSTATE_CNT(CMS_USER, user_cnt);
1054 GET_CPU_MSTATE_CNT(CMS_SYSTEM, system_cnt);
1055
1056 /*
1057 * We can't do anything when we have just switched to a state
1058 * because there is no valid timestamp.
1059 */
1060 if (cpupm->lastquan_ticks == 0) {
1061 cpupm->lastquan_ticks = NSEC_TO_TICK(gethrtime());
1062 CPUDRV_MONITOR_INIT(cpudsp);
1063 mutex_exit(&cpudsp->lock);
1064 goto do_return;
1065 }
1066
1067 /*
1068 * Various watermarks are based on this routine being called back
1069 * exactly at the requested period. This is not guaranteed
1070 * because this routine is called from a taskq that is dispatched
1071 * from a timeout routine. Handle this by finding out how many
1072 * ticks have elapsed since the last call and adjusting
1073 * the idle_cnt based on the delay added to the requested period
1074 * by timeout and taskq.
1075 */
1076 ticks = NSEC_TO_TICK(gethrtime());
1077 tick_cnt = ticks - cpupm->lastquan_ticks;
1078 ASSERT(tick_cnt != 0);
1079 cpupm->lastquan_ticks = ticks;
1080
1081 /*
1082 * Time taken between recording the current counts and
1083 * arranging the next call of this routine is an error in our
1084 * calculation. We minimize the error by calling
1085 * CPUDRV_MONITOR_INIT() here instead of end of this routine.
1086 */
1087 CPUDRV_MONITOR_INIT(cpudsp);
1088 DPRINTF(D_PM_MONITOR_VERBOSE, ("cpudrv_monitor: instance %d: "
1089 "idle count %d, user count %d, system count %d, pm_level %d, "
1090 "pm_busycnt %d\n", ddi_get_instance(dip), idle_cnt, user_cnt,
1091 system_cnt, cur_spd->pm_level, cpupm->pm_busycnt));
1092
1093 #ifdef DEBUG
1094 /*
1095 * Notify that timeout and taskq has caused delays and we need to
1096 * scale our parameters accordingly.
1097 *
1098 * To get accurate result, don't turn on other DPRINTFs with
1099 * the following DPRINTF. PROM calls generated by other
1100 * DPRINTFs changes the timing.
1101 */
1102 if (tick_cnt > cur_spd->quant_cnt) {
1103 DPRINTF(D_PM_MONITOR_DELAY, ("cpudrv_monitor: instance %d: "
1104 "tick count %d > quantum_count %u\n",
1105 ddi_get_instance(dip), tick_cnt, cur_spd->quant_cnt));
1106 }
1107 #endif /* DEBUG */
1108
1109 /*
1110 * Adjust counts based on the delay added by timeout and taskq.
1111 */
1112 idle_cnt = (idle_cnt * cur_spd->quant_cnt) / tick_cnt;
1113 user_cnt = (user_cnt * cur_spd->quant_cnt) / tick_cnt;
1114
1115 if ((user_cnt > cur_spd->user_hwm) || (idle_cnt < cur_spd->idle_lwm &&
1116 cur_spd->idle_blwm_cnt >= cpudrv_idle_blwm_cnt_max)) {
1117 cur_spd->idle_blwm_cnt = 0;
1118 cur_spd->idle_bhwm_cnt = 0;
1119 /*
1120 * In normal situation, arrange to go to next higher speed.
1121 * If we are running in special direct pm mode, we just stay
1122 * at the current speed.
1123 */
1124 if (cur_spd == cur_spd->up_spd || cpudrv_direct_pm) {
1125 CPUDRV_MONITOR_PM_BUSY_COMP(dip, cpupm);
1126 } else {
1127 new_spd = cur_spd->up_spd;
1128 CPUDRV_MONITOR_PM_BUSY_AND_RAISE(dip, cpudsp, cpupm,
1129 new_spd);
1130 }
1131 } else if ((user_cnt <= cur_spd->user_lwm) &&
1132 (idle_cnt >= cur_spd->idle_hwm) || !CPU_ACTIVE(cpudsp->cp)) {
1133 cur_spd->idle_blwm_cnt = 0;
1134 cur_spd->idle_bhwm_cnt = 0;
1135 /*
1136 * Arrange to go to next lower speed by informing our idle
1137 * status to the power management framework.
1138 */
1139 CPUDRV_MONITOR_PM_IDLE_COMP(dip, cpupm);
1140 } else {
1141 /*
1142 * If we are between the idle water marks and have not
1143 * been here enough consecutive times to be considered
1144 * busy, just increment the count and return.
1145 */
1146 if ((idle_cnt < cur_spd->idle_hwm) &&
1147 (idle_cnt >= cur_spd->idle_lwm) &&
1148 (cur_spd->idle_bhwm_cnt < cpudrv_idle_bhwm_cnt_max)) {
1149 cur_spd->idle_blwm_cnt = 0;
1150 cur_spd->idle_bhwm_cnt++;
1151 mutex_exit(&cpudsp->lock);
1152 goto do_return;
1153 }
1154 if (idle_cnt < cur_spd->idle_lwm) {
1155 cur_spd->idle_blwm_cnt++;
1156 cur_spd->idle_bhwm_cnt = 0;
1157 }
1158 /*
1159 * Arranges to stay at the current speed.
1160 */
1161 CPUDRV_MONITOR_PM_BUSY_COMP(dip, cpupm);
1162 }
1163 mutex_exit(&cpudsp->lock);
1164 do_return:
1165 mutex_enter(&cpupm->timeout_lock);
1166 ASSERT(cpupm->timeout_count > 0);
1167 cpupm->timeout_count--;
1168 cv_signal(&cpupm->timeout_cv);
1169 mutex_exit(&cpupm->timeout_lock);
1170 }
1171
1172 /*
1173 * get cpu_t structure for cpudrv_devstate_t
1174 */
1175 int
1176 cpudrv_get_cpu(cpudrv_devstate_t *cpudsp)
1177 {
1178 ASSERT(cpudsp != NULL);
1179
1180 /*
1181 * return DDI_SUCCESS if cpudrv_devstate_t
1182 * already contains cpu_t structure
1183 */
1184 if (cpudsp->cp != NULL)
1185 return (DDI_SUCCESS);
1186
1187 if (MUTEX_HELD(&cpu_lock)) {
1188 cpudsp->cp = cpu_get(cpudsp->cpu_id);
1189 } else {
1190 mutex_enter(&cpu_lock);
1191 cpudsp->cp = cpu_get(cpudsp->cpu_id);
1192 mutex_exit(&cpu_lock);
1193 }
1194
1195 if (cpudsp->cp == NULL)
1196 return (DDI_FAILURE);
1197
1198 return (DDI_SUCCESS);
1199 }