xref: /linux/drivers/macintosh/windfarm_rm31.c (revision ca55b2fef3a9373fcfc30f82fd26bc7fccbda732)
1 /*
2  * Windfarm PowerMac thermal control.
3  * Control loops for RackMack3,1 (Xserve G5)
4  *
5  * Copyright (C) 2012 Benjamin Herrenschmidt, IBM Corp.
6  *
7  * Use and redistribute under the terms of the GNU GPL v2.
8  */
9 #include <linux/types.h>
10 #include <linux/errno.h>
11 #include <linux/kernel.h>
12 #include <linux/device.h>
13 #include <linux/platform_device.h>
14 #include <linux/reboot.h>
15 #include <asm/prom.h>
16 #include <asm/smu.h>
17 
18 #include "windfarm.h"
19 #include "windfarm_pid.h"
20 #include "windfarm_mpu.h"
21 
22 #define VERSION "1.0"
23 
24 #undef DEBUG
25 #undef LOTSA_DEBUG
26 
27 #ifdef DEBUG
28 #define DBG(args...)	printk(args)
29 #else
30 #define DBG(args...)	do { } while(0)
31 #endif
32 
33 #ifdef LOTSA_DEBUG
34 #define DBG_LOTS(args...)	printk(args)
35 #else
36 #define DBG_LOTS(args...)	do { } while(0)
37 #endif
38 
39 /* define this to force CPU overtemp to 60 degree, useful for testing
40  * the overtemp code
41  */
42 #undef HACKED_OVERTEMP
43 
44 /* We currently only handle 2 chips */
45 #define NR_CHIPS	2
46 #define NR_CPU_FANS	3 * NR_CHIPS
47 
48 /* Controls and sensors */
49 static struct wf_sensor *sens_cpu_temp[NR_CHIPS];
50 static struct wf_sensor *sens_cpu_volts[NR_CHIPS];
51 static struct wf_sensor *sens_cpu_amps[NR_CHIPS];
52 static struct wf_sensor *backside_temp;
53 static struct wf_sensor *slots_temp;
54 static struct wf_sensor *dimms_temp;
55 
56 static struct wf_control *cpu_fans[NR_CHIPS][3];
57 static struct wf_control *backside_fan;
58 static struct wf_control *slots_fan;
59 static struct wf_control *cpufreq_clamp;
60 
61 /* We keep a temperature history for average calculation of 180s */
62 #define CPU_TEMP_HIST_SIZE	180
63 
64 /* PID loop state */
65 static const struct mpu_data *cpu_mpu_data[NR_CHIPS];
66 static struct wf_cpu_pid_state cpu_pid[NR_CHIPS];
67 static u32 cpu_thist[CPU_TEMP_HIST_SIZE];
68 static int cpu_thist_pt;
69 static s64 cpu_thist_total;
70 static s32 cpu_all_tmax = 100 << 16;
71 static struct wf_pid_state backside_pid;
72 static int backside_tick;
73 static struct wf_pid_state slots_pid;
74 static int slots_tick;
75 static int slots_speed;
76 static struct wf_pid_state dimms_pid;
77 static int dimms_output_clamp;
78 
79 static int nr_chips;
80 static bool have_all_controls;
81 static bool have_all_sensors;
82 static bool started;
83 
84 static int failure_state;
85 #define FAILURE_SENSOR		1
86 #define FAILURE_FAN		2
87 #define FAILURE_PERM		4
88 #define FAILURE_LOW_OVERTEMP	8
89 #define FAILURE_HIGH_OVERTEMP	16
90 
91 /* Overtemp values */
92 #define LOW_OVER_AVERAGE	0
93 #define LOW_OVER_IMMEDIATE	(10 << 16)
94 #define LOW_OVER_CLEAR		((-10) << 16)
95 #define HIGH_OVER_IMMEDIATE	(14 << 16)
96 #define HIGH_OVER_AVERAGE	(10 << 16)
97 #define HIGH_OVER_IMMEDIATE	(14 << 16)
98 
99 
100 static void cpu_max_all_fans(void)
101 {
102 	int i;
103 
104 	/* We max all CPU fans in case of a sensor error. We also do the
105 	 * cpufreq clamping now, even if it's supposedly done later by the
106 	 * generic code anyway, we do it earlier here to react faster
107 	 */
108 	if (cpufreq_clamp)
109 		wf_control_set_max(cpufreq_clamp);
110 	for (i = 0; i < nr_chips; i++) {
111 		if (cpu_fans[i][0])
112 			wf_control_set_max(cpu_fans[i][0]);
113 		if (cpu_fans[i][1])
114 			wf_control_set_max(cpu_fans[i][1]);
115 		if (cpu_fans[i][2])
116 			wf_control_set_max(cpu_fans[i][2]);
117 	}
118 }
119 
120 static int cpu_check_overtemp(s32 temp)
121 {
122 	int new_state = 0;
123 	s32 t_avg, t_old;
124 	static bool first = true;
125 
126 	/* First check for immediate overtemps */
127 	if (temp >= (cpu_all_tmax + LOW_OVER_IMMEDIATE)) {
128 		new_state |= FAILURE_LOW_OVERTEMP;
129 		if ((failure_state & FAILURE_LOW_OVERTEMP) == 0)
130 			printk(KERN_ERR "windfarm: Overtemp due to immediate CPU"
131 			       " temperature !\n");
132 	}
133 	if (temp >= (cpu_all_tmax + HIGH_OVER_IMMEDIATE)) {
134 		new_state |= FAILURE_HIGH_OVERTEMP;
135 		if ((failure_state & FAILURE_HIGH_OVERTEMP) == 0)
136 			printk(KERN_ERR "windfarm: Critical overtemp due to"
137 			       " immediate CPU temperature !\n");
138 	}
139 
140 	/*
141 	 * The first time around, initialize the array with the first
142 	 * temperature reading
143 	 */
144 	if (first) {
145 		int i;
146 
147 		cpu_thist_total = 0;
148 		for (i = 0; i < CPU_TEMP_HIST_SIZE; i++) {
149 			cpu_thist[i] = temp;
150 			cpu_thist_total += temp;
151 		}
152 		first = false;
153 	}
154 
155 	/*
156 	 * We calculate a history of max temperatures and use that for the
157 	 * overtemp management
158 	 */
159 	t_old = cpu_thist[cpu_thist_pt];
160 	cpu_thist[cpu_thist_pt] = temp;
161 	cpu_thist_pt = (cpu_thist_pt + 1) % CPU_TEMP_HIST_SIZE;
162 	cpu_thist_total -= t_old;
163 	cpu_thist_total += temp;
164 	t_avg = cpu_thist_total / CPU_TEMP_HIST_SIZE;
165 
166 	DBG_LOTS("  t_avg = %d.%03d (out: %d.%03d, in: %d.%03d)\n",
167 		 FIX32TOPRINT(t_avg), FIX32TOPRINT(t_old), FIX32TOPRINT(temp));
168 
169 	/* Now check for average overtemps */
170 	if (t_avg >= (cpu_all_tmax + LOW_OVER_AVERAGE)) {
171 		new_state |= FAILURE_LOW_OVERTEMP;
172 		if ((failure_state & FAILURE_LOW_OVERTEMP) == 0)
173 			printk(KERN_ERR "windfarm: Overtemp due to average CPU"
174 			       " temperature !\n");
175 	}
176 	if (t_avg >= (cpu_all_tmax + HIGH_OVER_AVERAGE)) {
177 		new_state |= FAILURE_HIGH_OVERTEMP;
178 		if ((failure_state & FAILURE_HIGH_OVERTEMP) == 0)
179 			printk(KERN_ERR "windfarm: Critical overtemp due to"
180 			       " average CPU temperature !\n");
181 	}
182 
183 	/* Now handle overtemp conditions. We don't currently use the windfarm
184 	 * overtemp handling core as it's not fully suited to the needs of those
185 	 * new machine. This will be fixed later.
186 	 */
187 	if (new_state) {
188 		/* High overtemp -> immediate shutdown */
189 		if (new_state & FAILURE_HIGH_OVERTEMP)
190 			machine_power_off();
191 		if ((failure_state & new_state) != new_state)
192 			cpu_max_all_fans();
193 		failure_state |= new_state;
194 	} else if ((failure_state & FAILURE_LOW_OVERTEMP) &&
195 		   (temp < (cpu_all_tmax + LOW_OVER_CLEAR))) {
196 		printk(KERN_ERR "windfarm: Overtemp condition cleared !\n");
197 		failure_state &= ~FAILURE_LOW_OVERTEMP;
198 	}
199 
200 	return failure_state & (FAILURE_LOW_OVERTEMP | FAILURE_HIGH_OVERTEMP);
201 }
202 
203 static int read_one_cpu_vals(int cpu, s32 *temp, s32 *power)
204 {
205 	s32 dtemp, volts, amps;
206 	int rc;
207 
208 	/* Get diode temperature */
209 	rc = wf_sensor_get(sens_cpu_temp[cpu], &dtemp);
210 	if (rc) {
211 		DBG("  CPU%d: temp reading error !\n", cpu);
212 		return -EIO;
213 	}
214 	DBG_LOTS("  CPU%d: temp   = %d.%03d\n", cpu, FIX32TOPRINT((dtemp)));
215 	*temp = dtemp;
216 
217 	/* Get voltage */
218 	rc = wf_sensor_get(sens_cpu_volts[cpu], &volts);
219 	if (rc) {
220 		DBG("  CPU%d, volts reading error !\n", cpu);
221 		return -EIO;
222 	}
223 	DBG_LOTS("  CPU%d: volts  = %d.%03d\n", cpu, FIX32TOPRINT((volts)));
224 
225 	/* Get current */
226 	rc = wf_sensor_get(sens_cpu_amps[cpu], &amps);
227 	if (rc) {
228 		DBG("  CPU%d, current reading error !\n", cpu);
229 		return -EIO;
230 	}
231 	DBG_LOTS("  CPU%d: amps   = %d.%03d\n", cpu, FIX32TOPRINT((amps)));
232 
233 	/* Calculate power */
234 
235 	/* Scale voltage and current raw sensor values according to fixed scales
236 	 * obtained in Darwin and calculate power from I and V
237 	 */
238 	*power = (((u64)volts) * ((u64)amps)) >> 16;
239 
240 	DBG_LOTS("  CPU%d: power  = %d.%03d\n", cpu, FIX32TOPRINT((*power)));
241 
242 	return 0;
243 
244 }
245 
246 static void cpu_fans_tick(void)
247 {
248 	int err, cpu, i;
249 	s32 speed, temp, power, t_max = 0;
250 
251 	DBG_LOTS("* cpu fans_tick_split()\n");
252 
253 	for (cpu = 0; cpu < nr_chips; ++cpu) {
254 		struct wf_cpu_pid_state *sp = &cpu_pid[cpu];
255 
256 		/* Read current speed */
257 		wf_control_get(cpu_fans[cpu][0], &sp->target);
258 
259 		err = read_one_cpu_vals(cpu, &temp, &power);
260 		if (err) {
261 			failure_state |= FAILURE_SENSOR;
262 			cpu_max_all_fans();
263 			return;
264 		}
265 
266 		/* Keep track of highest temp */
267 		t_max = max(t_max, temp);
268 
269 		/* Handle possible overtemps */
270 		if (cpu_check_overtemp(t_max))
271 			return;
272 
273 		/* Run PID */
274 		wf_cpu_pid_run(sp, power, temp);
275 
276 		DBG_LOTS("  CPU%d: target = %d RPM\n", cpu, sp->target);
277 
278 		/* Apply DIMMs clamp */
279 		speed = max(sp->target, dimms_output_clamp);
280 
281 		/* Apply result to all cpu fans */
282 		for (i = 0; i < 3; i++) {
283 			err = wf_control_set(cpu_fans[cpu][i], speed);
284 			if (err) {
285 				pr_warning("wf_rm31: Fan %s reports error %d\n",
286 					   cpu_fans[cpu][i]->name, err);
287 				failure_state |= FAILURE_FAN;
288 			}
289 		}
290 	}
291 }
292 
293 /* Implementation... */
294 static int cpu_setup_pid(int cpu)
295 {
296 	struct wf_cpu_pid_param pid;
297 	const struct mpu_data *mpu = cpu_mpu_data[cpu];
298 	s32 tmax, ttarget, ptarget;
299 	int fmin, fmax, hsize;
300 
301 	/* Get PID params from the appropriate MPU EEPROM */
302 	tmax = mpu->tmax << 16;
303 	ttarget = mpu->ttarget << 16;
304 	ptarget = ((s32)(mpu->pmaxh - mpu->padjmax)) << 16;
305 
306 	DBG("wf_72: CPU%d ttarget = %d.%03d, tmax = %d.%03d\n",
307 	    cpu, FIX32TOPRINT(ttarget), FIX32TOPRINT(tmax));
308 
309 	/* We keep a global tmax for overtemp calculations */
310 	if (tmax < cpu_all_tmax)
311 		cpu_all_tmax = tmax;
312 
313 	/* Set PID min/max by using the rear fan min/max */
314 	fmin = wf_control_get_min(cpu_fans[cpu][0]);
315 	fmax = wf_control_get_max(cpu_fans[cpu][0]);
316 	DBG("wf_72: CPU%d max RPM range = [%d..%d]\n", cpu, fmin, fmax);
317 
318 	/* History size */
319 	hsize = min_t(int, mpu->tguardband, WF_PID_MAX_HISTORY);
320 	DBG("wf_72: CPU%d history size = %d\n", cpu, hsize);
321 
322 	/* Initialize PID loop */
323 	pid.interval	= 1;	/* seconds */
324 	pid.history_len = hsize;
325 	pid.gd		= mpu->pid_gd;
326 	pid.gp		= mpu->pid_gp;
327 	pid.gr		= mpu->pid_gr;
328 	pid.tmax	= tmax;
329 	pid.ttarget	= ttarget;
330 	pid.pmaxadj	= ptarget;
331 	pid.min		= fmin;
332 	pid.max		= fmax;
333 
334 	wf_cpu_pid_init(&cpu_pid[cpu], &pid);
335 	cpu_pid[cpu].target = 4000;
336 
337 	return 0;
338 }
339 
340 /* Backside/U3 fan */
341 static struct wf_pid_param backside_param = {
342 	.interval	= 1,
343 	.history_len	= 2,
344 	.gd		= 0x00500000,
345 	.gp		= 0x0004cccc,
346 	.gr		= 0,
347 	.itarget	= 70 << 16,
348 	.additive	= 0,
349 	.min		= 20,
350 	.max		= 100,
351 };
352 
353 /* DIMMs temperature (clamp the backside fan) */
354 static struct wf_pid_param dimms_param = {
355 	.interval	= 1,
356 	.history_len	= 20,
357 	.gd		= 0,
358 	.gp		= 0,
359 	.gr		= 0x06553600,
360 	.itarget	= 50 << 16,
361 	.additive	= 0,
362 	.min		= 4000,
363 	.max		= 14000,
364 };
365 
366 static void backside_fan_tick(void)
367 {
368 	s32 temp, dtemp;
369 	int speed, dspeed, fan_min;
370 	int err;
371 
372 	if (!backside_fan || !backside_temp || !dimms_temp || !backside_tick)
373 		return;
374 	if (--backside_tick > 0)
375 		return;
376 	backside_tick = backside_pid.param.interval;
377 
378 	DBG_LOTS("* backside fans tick\n");
379 
380 	/* Update fan speed from actual fans */
381 	err = wf_control_get(backside_fan, &speed);
382 	if (!err)
383 		backside_pid.target = speed;
384 
385 	err = wf_sensor_get(backside_temp, &temp);
386 	if (err) {
387 		printk(KERN_WARNING "windfarm: U3 temp sensor error %d\n",
388 		       err);
389 		failure_state |= FAILURE_SENSOR;
390 		wf_control_set_max(backside_fan);
391 		return;
392 	}
393 	speed = wf_pid_run(&backside_pid, temp);
394 
395 	DBG_LOTS("backside PID temp=%d.%.3d speed=%d\n",
396 		 FIX32TOPRINT(temp), speed);
397 
398 	err = wf_sensor_get(dimms_temp, &dtemp);
399 	if (err) {
400 		printk(KERN_WARNING "windfarm: DIMMs temp sensor error %d\n",
401 		       err);
402 		failure_state |= FAILURE_SENSOR;
403 		wf_control_set_max(backside_fan);
404 		return;
405 	}
406 	dspeed = wf_pid_run(&dimms_pid, dtemp);
407 	dimms_output_clamp = dspeed;
408 
409 	fan_min = (dspeed * 100) / 14000;
410 	fan_min = max(fan_min, backside_param.min);
411 	speed = max(speed, fan_min);
412 
413 	err = wf_control_set(backside_fan, speed);
414 	if (err) {
415 		printk(KERN_WARNING "windfarm: backside fan error %d\n", err);
416 		failure_state |= FAILURE_FAN;
417 	}
418 }
419 
420 static void backside_setup_pid(void)
421 {
422 	/* first time initialize things */
423 	s32 fmin = wf_control_get_min(backside_fan);
424 	s32 fmax = wf_control_get_max(backside_fan);
425 	struct wf_pid_param param;
426 
427 	param = backside_param;
428 	param.min = max(param.min, fmin);
429 	param.max = min(param.max, fmax);
430 	wf_pid_init(&backside_pid, &param);
431 
432 	param = dimms_param;
433 	wf_pid_init(&dimms_pid, &param);
434 
435 	backside_tick = 1;
436 
437 	pr_info("wf_rm31: Backside control loop started.\n");
438 }
439 
440 /* Slots fan */
441 static const struct wf_pid_param slots_param = {
442 	.interval	= 1,
443 	.history_len	= 20,
444 	.gd		= 0,
445 	.gp		= 0,
446 	.gr		= 0x00100000,
447 	.itarget	= 3200000,
448 	.additive	= 0,
449 	.min		= 20,
450 	.max		= 100,
451 };
452 
453 static void slots_fan_tick(void)
454 {
455 	s32 temp;
456 	int speed;
457 	int err;
458 
459 	if (!slots_fan || !slots_temp || !slots_tick)
460 		return;
461 	if (--slots_tick > 0)
462 		return;
463 	slots_tick = slots_pid.param.interval;
464 
465 	DBG_LOTS("* slots fans tick\n");
466 
467 	err = wf_sensor_get(slots_temp, &temp);
468 	if (err) {
469 		pr_warning("wf_rm31: slots temp sensor error %d\n", err);
470 		failure_state |= FAILURE_SENSOR;
471 		wf_control_set_max(slots_fan);
472 		return;
473 	}
474 	speed = wf_pid_run(&slots_pid, temp);
475 
476 	DBG_LOTS("slots PID temp=%d.%.3d speed=%d\n",
477 		 FIX32TOPRINT(temp), speed);
478 
479 	slots_speed = speed;
480 	err = wf_control_set(slots_fan, speed);
481 	if (err) {
482 		printk(KERN_WARNING "windfarm: slots bay fan error %d\n", err);
483 		failure_state |= FAILURE_FAN;
484 	}
485 }
486 
487 static void slots_setup_pid(void)
488 {
489 	/* first time initialize things */
490 	s32 fmin = wf_control_get_min(slots_fan);
491 	s32 fmax = wf_control_get_max(slots_fan);
492 	struct wf_pid_param param = slots_param;
493 
494 	param.min = max(param.min, fmin);
495 	param.max = min(param.max, fmax);
496 	wf_pid_init(&slots_pid, &param);
497 	slots_tick = 1;
498 
499 	pr_info("wf_rm31: Slots control loop started.\n");
500 }
501 
502 static void set_fail_state(void)
503 {
504 	cpu_max_all_fans();
505 
506 	if (backside_fan)
507 		wf_control_set_max(backside_fan);
508 	if (slots_fan)
509 		wf_control_set_max(slots_fan);
510 }
511 
512 static void rm31_tick(void)
513 {
514 	int i, last_failure;
515 
516 	if (!started) {
517 		started = 1;
518 		printk(KERN_INFO "windfarm: CPUs control loops started.\n");
519 		for (i = 0; i < nr_chips; ++i) {
520 			if (cpu_setup_pid(i) < 0) {
521 				failure_state = FAILURE_PERM;
522 				set_fail_state();
523 				break;
524 			}
525 		}
526 		DBG_LOTS("cpu_all_tmax=%d.%03d\n", FIX32TOPRINT(cpu_all_tmax));
527 
528 		backside_setup_pid();
529 		slots_setup_pid();
530 
531 #ifdef HACKED_OVERTEMP
532 		cpu_all_tmax = 60 << 16;
533 #endif
534 	}
535 
536 	/* Permanent failure, bail out */
537 	if (failure_state & FAILURE_PERM)
538 		return;
539 
540 	/*
541 	 * Clear all failure bits except low overtemp which will be eventually
542 	 * cleared by the control loop itself
543 	 */
544 	last_failure = failure_state;
545 	failure_state &= FAILURE_LOW_OVERTEMP;
546 	backside_fan_tick();
547 	slots_fan_tick();
548 
549 	/* We do CPUs last because they can be clamped high by
550 	 * DIMM temperature
551 	 */
552 	cpu_fans_tick();
553 
554 	DBG_LOTS("  last_failure: 0x%x, failure_state: %x\n",
555 		 last_failure, failure_state);
556 
557 	/* Check for failures. Any failure causes cpufreq clamping */
558 	if (failure_state && last_failure == 0 && cpufreq_clamp)
559 		wf_control_set_max(cpufreq_clamp);
560 	if (failure_state == 0 && last_failure && cpufreq_clamp)
561 		wf_control_set_min(cpufreq_clamp);
562 
563 	/* That's it for now, we might want to deal with other failures
564 	 * differently in the future though
565 	 */
566 }
567 
568 static void rm31_new_control(struct wf_control *ct)
569 {
570 	bool all_controls;
571 
572 	if (!strcmp(ct->name, "cpu-fan-a-0"))
573 		cpu_fans[0][0] = ct;
574 	else if (!strcmp(ct->name, "cpu-fan-b-0"))
575 		cpu_fans[0][1] = ct;
576 	else if (!strcmp(ct->name, "cpu-fan-c-0"))
577 		cpu_fans[0][2] = ct;
578 	else if (!strcmp(ct->name, "cpu-fan-a-1"))
579 		cpu_fans[1][0] = ct;
580 	else if (!strcmp(ct->name, "cpu-fan-b-1"))
581 		cpu_fans[1][1] = ct;
582 	else if (!strcmp(ct->name, "cpu-fan-c-1"))
583 		cpu_fans[1][2] = ct;
584 	else if (!strcmp(ct->name, "backside-fan"))
585 		backside_fan = ct;
586 	else if (!strcmp(ct->name, "slots-fan"))
587 		slots_fan = ct;
588 	else if (!strcmp(ct->name, "cpufreq-clamp"))
589 		cpufreq_clamp = ct;
590 
591 	all_controls =
592 		cpu_fans[0][0] &&
593 		cpu_fans[0][1] &&
594 		cpu_fans[0][2] &&
595 		backside_fan &&
596 		slots_fan;
597 	if (nr_chips > 1)
598 		all_controls &=
599 			cpu_fans[1][0] &&
600 			cpu_fans[1][1] &&
601 			cpu_fans[1][2];
602 	have_all_controls = all_controls;
603 }
604 
605 
606 static void rm31_new_sensor(struct wf_sensor *sr)
607 {
608 	bool all_sensors;
609 
610 	if (!strcmp(sr->name, "cpu-diode-temp-0"))
611 		sens_cpu_temp[0] = sr;
612 	else if (!strcmp(sr->name, "cpu-diode-temp-1"))
613 		sens_cpu_temp[1] = sr;
614 	else if (!strcmp(sr->name, "cpu-voltage-0"))
615 		sens_cpu_volts[0] = sr;
616 	else if (!strcmp(sr->name, "cpu-voltage-1"))
617 		sens_cpu_volts[1] = sr;
618 	else if (!strcmp(sr->name, "cpu-current-0"))
619 		sens_cpu_amps[0] = sr;
620 	else if (!strcmp(sr->name, "cpu-current-1"))
621 		sens_cpu_amps[1] = sr;
622 	else if (!strcmp(sr->name, "backside-temp"))
623 		backside_temp = sr;
624 	else if (!strcmp(sr->name, "slots-temp"))
625 		slots_temp = sr;
626 	else if (!strcmp(sr->name, "dimms-temp"))
627 		dimms_temp = sr;
628 
629 	all_sensors =
630 		sens_cpu_temp[0] &&
631 		sens_cpu_volts[0] &&
632 		sens_cpu_amps[0] &&
633 		backside_temp &&
634 		slots_temp &&
635 		dimms_temp;
636 	if (nr_chips > 1)
637 		all_sensors &=
638 			sens_cpu_temp[1] &&
639 			sens_cpu_volts[1] &&
640 			sens_cpu_amps[1];
641 
642 	have_all_sensors = all_sensors;
643 }
644 
645 static int rm31_wf_notify(struct notifier_block *self,
646 			  unsigned long event, void *data)
647 {
648 	switch (event) {
649 	case WF_EVENT_NEW_SENSOR:
650 		rm31_new_sensor(data);
651 		break;
652 	case WF_EVENT_NEW_CONTROL:
653 		rm31_new_control(data);
654 		break;
655 	case WF_EVENT_TICK:
656 		if (have_all_controls && have_all_sensors)
657 			rm31_tick();
658 	}
659 	return 0;
660 }
661 
662 static struct notifier_block rm31_events = {
663 	.notifier_call = rm31_wf_notify,
664 };
665 
666 static int wf_rm31_probe(struct platform_device *dev)
667 {
668 	wf_register_client(&rm31_events);
669 	return 0;
670 }
671 
672 static int wf_rm31_remove(struct platform_device *dev)
673 {
674 	wf_unregister_client(&rm31_events);
675 
676 	/* should release all sensors and controls */
677 	return 0;
678 }
679 
680 static struct platform_driver wf_rm31_driver = {
681 	.probe	= wf_rm31_probe,
682 	.remove	= wf_rm31_remove,
683 	.driver	= {
684 		.name = "windfarm",
685 		.owner	= THIS_MODULE,
686 	},
687 };
688 
689 static int __init wf_rm31_init(void)
690 {
691 	struct device_node *cpu;
692 	int i;
693 
694 	if (!of_machine_is_compatible("RackMac3,1"))
695 		return -ENODEV;
696 
697 	/* Count the number of CPU cores */
698 	nr_chips = 0;
699 	for_each_node_by_type(cpu, "cpu")
700 		++nr_chips;
701 	if (nr_chips > NR_CHIPS)
702 		nr_chips = NR_CHIPS;
703 
704 	pr_info("windfarm: Initializing for desktop G5 with %d chips\n",
705 		nr_chips);
706 
707 	/* Get MPU data for each CPU */
708 	for (i = 0; i < nr_chips; i++) {
709 		cpu_mpu_data[i] = wf_get_mpu(i);
710 		if (!cpu_mpu_data[i]) {
711 			pr_err("wf_rm31: Failed to find MPU data for CPU %d\n", i);
712 			return -ENXIO;
713 		}
714 	}
715 
716 #ifdef MODULE
717 	request_module("windfarm_fcu_controls");
718 	request_module("windfarm_lm75_sensor");
719 	request_module("windfarm_lm87_sensor");
720 	request_module("windfarm_ad7417_sensor");
721 	request_module("windfarm_max6690_sensor");
722 	request_module("windfarm_cpufreq_clamp");
723 #endif /* MODULE */
724 
725 	platform_driver_register(&wf_rm31_driver);
726 	return 0;
727 }
728 
729 static void __exit wf_rm31_exit(void)
730 {
731 	platform_driver_unregister(&wf_rm31_driver);
732 }
733 
734 module_init(wf_rm31_init);
735 module_exit(wf_rm31_exit);
736 
737 MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
738 MODULE_DESCRIPTION("Thermal control for Xserve G5");
739 MODULE_LICENSE("GPL");
740 MODULE_ALIAS("platform:windfarm");
741