1 /*
2  * Windfarm PowerMac thermal control. iMac G5
3  *
4  * (c) Copyright 2005 Benjamin Herrenschmidt, IBM Corp.
5  *                    <benh@kernel.crashing.org>
6  *
7  * Released under the term of the GNU GPL v2.
8  *
9  * The algorithm used is the PID control algorithm, used the same
10  * way the published Darwin code does, using the same values that
11  * are present in the Darwin 8.2 snapshot property lists (note however
12  * that none of the code has been re-used, it's a complete re-implementation
13  *
14  * The various control loops found in Darwin config file are:
15  *
16  * PowerMac8,1 and PowerMac8,2
17  * ===========================
18  *
19  * System Fans control loop. Different based on models. In addition to the
20  * usual PID algorithm, the control loop gets 2 additional pairs of linear
21  * scaling factors (scale/offsets) expressed as 4.12 fixed point values
22  * signed offset, unsigned scale)
23  *
24  * The targets are modified such as:
25  *  - the linked control (second control) gets the target value as-is
26  *    (typically the drive fan)
27  *  - the main control (first control) gets the target value scaled with
28  *    the first pair of factors, and is then modified as below
29  *  - the value of the target of the CPU Fan control loop is retrieved,
30  *    scaled with the second pair of factors, and the max of that and
31  *    the scaled target is applied to the main control.
32  *
33  * # model_id: 2
34  *   controls       : system-fan, drive-bay-fan
35  *   sensors        : hd-temp
36  *   PID params     : G_d = 0x15400000
37  *                    G_p = 0x00200000
38  *                    G_r = 0x000002fd
39  *                    History = 2 entries
40  *                    Input target = 0x3a0000
41  *                    Interval = 5s
42  *   linear-factors : offset = 0xff38 scale  = 0x0ccd
43  *                    offset = 0x0208 scale  = 0x07ae
44  *
45  * # model_id: 3
46  *   controls       : system-fan, drive-bay-fan
47  *   sensors        : hd-temp
48  *   PID params     : G_d = 0x08e00000
49  *                    G_p = 0x00566666
50  *                    G_r = 0x0000072b
51  *                    History = 2 entries
52  *                    Input target = 0x350000
53  *                    Interval = 5s
54  *   linear-factors : offset = 0xff38 scale  = 0x0ccd
55  *                    offset = 0x0000 scale  = 0x0000
56  *
57  * # model_id: 5
58  *   controls       : system-fan
59  *   sensors        : hd-temp
60  *   PID params     : G_d = 0x15400000
61  *                    G_p = 0x00233333
62  *                    G_r = 0x000002fd
63  *                    History = 2 entries
64  *                    Input target = 0x3a0000
65  *                    Interval = 5s
66  *   linear-factors : offset = 0x0000 scale  = 0x1000
67  *                    offset = 0x0091 scale  = 0x0bae
68  *
69  * CPU Fan control loop. The loop is identical for all models. it
70  * has an additional pair of scaling factor. This is used to scale the
71  * systems fan control loop target result (the one before it gets scaled
72  * by the System Fans control loop itself). Then, the max value of the
73  * calculated target value and system fan value is sent to the fans
74  *
75  *   controls       : cpu-fan
76  *   sensors        : cpu-temp cpu-power
77  *   PID params     : From SMU sdb partition
78  *   linear-factors : offset = 0xfb50 scale  = 0x1000
79  *
80  * CPU Slew control loop. Not implemented. The cpufreq driver in linux is
81  * completely separate for now, though we could find a way to link it, either
82  * as a client reacting to overtemp notifications, or directling monitoring
83  * the CPU temperature
84  *
85  * WARNING ! The CPU control loop requires the CPU tmax for the current
86  * operating point. However, we currently are completely separated from
87  * the cpufreq driver and thus do not know what the current operating
88  * point is. Fortunately, we also do not have any hardware supporting anything
89  * but operating point 0 at the moment, thus we just peek that value directly
90  * from the SDB partition. If we ever end up with actually slewing the system
91  * clock and thus changing operating points, we'll have to find a way to
92  * communicate with the CPU freq driver;
93  *
94  */
95 
96 #include <linux/types.h>
97 #include <linux/errno.h>
98 #include <linux/kernel.h>
99 #include <linux/delay.h>
100 #include <linux/slab.h>
101 #include <linux/init.h>
102 #include <linux/spinlock.h>
103 #include <linux/wait.h>
104 #include <linux/kmod.h>
105 #include <linux/device.h>
106 #include <linux/platform_device.h>
107 #include <asm/prom.h>
108 #include <asm/machdep.h>
109 #include <asm/io.h>
110 #include <asm/sections.h>
111 #include <asm/smu.h>
112 
113 #include "windfarm.h"
114 #include "windfarm_pid.h"
115 
116 #define VERSION "0.4"
117 
118 #undef DEBUG
119 
120 #ifdef DEBUG
121 #define DBG(args...)	printk(args)
122 #else
123 #define DBG(args...)	do { } while(0)
124 #endif
125 
126 /* define this to force CPU overtemp to 74 degree, useful for testing
127  * the overtemp code
128  */
129 #undef HACKED_OVERTEMP
130 
131 static int wf_smu_mach_model;	/* machine model id */
132 
133 /* Controls & sensors */
134 static struct wf_sensor	*sensor_cpu_power;
135 static struct wf_sensor	*sensor_cpu_temp;
136 static struct wf_sensor	*sensor_hd_temp;
137 static struct wf_control *fan_cpu_main;
138 static struct wf_control *fan_hd;
139 static struct wf_control *fan_system;
140 static struct wf_control *cpufreq_clamp;
141 
142 /* Set to kick the control loop into life */
143 static int wf_smu_all_controls_ok, wf_smu_all_sensors_ok, wf_smu_started;
144 
145 /* Failure handling.. could be nicer */
146 #define FAILURE_FAN		0x01
147 #define FAILURE_SENSOR		0x02
148 #define FAILURE_OVERTEMP	0x04
149 
150 static unsigned int wf_smu_failure_state;
151 static int wf_smu_readjust, wf_smu_skipping;
152 
153 /*
154  * ****** System Fans Control Loop ******
155  *
156  */
157 
158 /* Parameters for the System Fans control loop. Parameters
159  * not in this table such as interval, history size, ...
160  * are common to all versions and thus hard coded for now.
161  */
162 struct wf_smu_sys_fans_param {
163 	int	model_id;
164 	s32	itarget;
165 	s32	gd, gp, gr;
166 
167 	s16	offset0;
168 	u16	scale0;
169 	s16	offset1;
170 	u16	scale1;
171 };
172 
173 #define WF_SMU_SYS_FANS_INTERVAL	5
174 #define WF_SMU_SYS_FANS_HISTORY_SIZE	2
175 
176 /* State data used by the system fans control loop
177  */
178 struct wf_smu_sys_fans_state {
179 	int			ticks;
180 	s32			sys_setpoint;
181 	s32			hd_setpoint;
182 	s16			offset0;
183 	u16			scale0;
184 	s16			offset1;
185 	u16			scale1;
186 	struct wf_pid_state	pid;
187 };
188 
189 /*
190  * Configs for SMU System Fan control loop
191  */
192 static struct wf_smu_sys_fans_param wf_smu_sys_all_params[] = {
193 	/* Model ID 2 */
194 	{
195 		.model_id	= 2,
196 		.itarget	= 0x3a0000,
197 		.gd		= 0x15400000,
198 		.gp		= 0x00200000,
199 		.gr		= 0x000002fd,
200 		.offset0	= 0xff38,
201 		.scale0		= 0x0ccd,
202 		.offset1	= 0x0208,
203 		.scale1		= 0x07ae,
204 	},
205 	/* Model ID 3 */
206 	{
207 		.model_id	= 3,
208 		.itarget	= 0x350000,
209 		.gd		= 0x08e00000,
210 		.gp		= 0x00566666,
211 		.gr		= 0x0000072b,
212 		.offset0	= 0xff38,
213 		.scale0		= 0x0ccd,
214 		.offset1	= 0x0000,
215 		.scale1		= 0x0000,
216 	},
217 	/* Model ID 5 */
218 	{
219 		.model_id	= 5,
220 		.itarget	= 0x3a0000,
221 		.gd		= 0x15400000,
222 		.gp		= 0x00233333,
223 		.gr		= 0x000002fd,
224 		.offset0	= 0x0000,
225 		.scale0		= 0x1000,
226 		.offset1	= 0x0091,
227 		.scale1		= 0x0bae,
228 	},
229 };
230 #define WF_SMU_SYS_FANS_NUM_CONFIGS ARRAY_SIZE(wf_smu_sys_all_params)
231 
232 static struct wf_smu_sys_fans_state *wf_smu_sys_fans;
233 
234 /*
235  * ****** CPU Fans Control Loop ******
236  *
237  */
238 
239 
240 #define WF_SMU_CPU_FANS_INTERVAL	1
241 #define WF_SMU_CPU_FANS_MAX_HISTORY	16
242 #define WF_SMU_CPU_FANS_SIBLING_SCALE	0x00001000
243 #define WF_SMU_CPU_FANS_SIBLING_OFFSET	0xfffffb50
244 
245 /* State data used by the cpu fans control loop
246  */
247 struct wf_smu_cpu_fans_state {
248 	int			ticks;
249 	s32			cpu_setpoint;
250 	s32			scale;
251 	s32			offset;
252 	struct wf_cpu_pid_state	pid;
253 };
254 
255 static struct wf_smu_cpu_fans_state *wf_smu_cpu_fans;
256 
257 
258 
259 /*
260  * ***** Implementation *****
261  *
262  */
263 
264 static void wf_smu_create_sys_fans(void)
265 {
266 	struct wf_smu_sys_fans_param *param = NULL;
267 	struct wf_pid_param pid_param;
268 	int i;
269 
270 	/* First, locate the params for this model */
271 	for (i = 0; i < WF_SMU_SYS_FANS_NUM_CONFIGS; i++)
272 		if (wf_smu_sys_all_params[i].model_id == wf_smu_mach_model) {
273 			param = &wf_smu_sys_all_params[i];
274 			break;
275 		}
276 
277 	/* No params found, put fans to max */
278 	if (param == NULL) {
279 		printk(KERN_WARNING "windfarm: System fan config not found "
280 		       "for this machine model, max fan speed\n");
281 		goto fail;
282 	}
283 
284 	/* Alloc & initialize state */
285 	wf_smu_sys_fans = kmalloc(sizeof(struct wf_smu_sys_fans_state),
286 				  GFP_KERNEL);
287 	if (wf_smu_sys_fans == NULL) {
288 		printk(KERN_WARNING "windfarm: Memory allocation error"
289 		       " max fan speed\n");
290 		goto fail;
291 	}
292 	wf_smu_sys_fans->ticks = 1;
293 	wf_smu_sys_fans->scale0 = param->scale0;
294 	wf_smu_sys_fans->offset0 = param->offset0;
295 	wf_smu_sys_fans->scale1 = param->scale1;
296 	wf_smu_sys_fans->offset1 = param->offset1;
297 
298 	/* Fill PID params */
299 	pid_param.gd = param->gd;
300 	pid_param.gp = param->gp;
301 	pid_param.gr = param->gr;
302 	pid_param.interval = WF_SMU_SYS_FANS_INTERVAL;
303 	pid_param.history_len = WF_SMU_SYS_FANS_HISTORY_SIZE;
304 	pid_param.itarget = param->itarget;
305 	pid_param.min = fan_system->ops->get_min(fan_system);
306 	pid_param.max = fan_system->ops->get_max(fan_system);
307 	if (fan_hd) {
308 		pid_param.min =
309 			max(pid_param.min,fan_hd->ops->get_min(fan_hd));
310 		pid_param.max =
311 			min(pid_param.max,fan_hd->ops->get_max(fan_hd));
312 	}
313 	wf_pid_init(&wf_smu_sys_fans->pid, &pid_param);
314 
315 	DBG("wf: System Fan control initialized.\n");
316 	DBG("    itarged=%d.%03d, min=%d RPM, max=%d RPM\n",
317 	    FIX32TOPRINT(pid_param.itarget), pid_param.min, pid_param.max);
318 	return;
319 
320  fail:
321 
322 	if (fan_system)
323 		wf_control_set_max(fan_system);
324 	if (fan_hd)
325 		wf_control_set_max(fan_hd);
326 }
327 
328 static void wf_smu_sys_fans_tick(struct wf_smu_sys_fans_state *st)
329 {
330 	s32 new_setpoint, temp, scaled, cputarget;
331 	int rc;
332 
333 	if (--st->ticks != 0) {
334 		if (wf_smu_readjust)
335 			goto readjust;
336 		return;
337 	}
338 	st->ticks = WF_SMU_SYS_FANS_INTERVAL;
339 
340 	rc = sensor_hd_temp->ops->get_value(sensor_hd_temp, &temp);
341 	if (rc) {
342 		printk(KERN_WARNING "windfarm: HD temp sensor error %d\n",
343 		       rc);
344 		wf_smu_failure_state |= FAILURE_SENSOR;
345 		return;
346 	}
347 
348 	DBG("wf_smu: System Fans tick ! HD temp: %d.%03d\n",
349 	    FIX32TOPRINT(temp));
350 
351 	if (temp > (st->pid.param.itarget + 0x50000))
352 		wf_smu_failure_state |= FAILURE_OVERTEMP;
353 
354 	new_setpoint = wf_pid_run(&st->pid, temp);
355 
356 	DBG("wf_smu: new_setpoint: %d RPM\n", (int)new_setpoint);
357 
358 	scaled = ((((s64)new_setpoint) * (s64)st->scale0) >> 12) + st->offset0;
359 
360 	DBG("wf_smu: scaled setpoint: %d RPM\n", (int)scaled);
361 
362 	cputarget = wf_smu_cpu_fans ? wf_smu_cpu_fans->pid.target : 0;
363 	cputarget = ((((s64)cputarget) * (s64)st->scale1) >> 12) + st->offset1;
364 	scaled = max(scaled, cputarget);
365 	scaled = max(scaled, st->pid.param.min);
366 	scaled = min(scaled, st->pid.param.max);
367 
368 	DBG("wf_smu: adjusted setpoint: %d RPM\n", (int)scaled);
369 
370 	if (st->sys_setpoint == scaled && new_setpoint == st->hd_setpoint)
371 		return;
372 	st->sys_setpoint = scaled;
373 	st->hd_setpoint = new_setpoint;
374  readjust:
375 	if (fan_system && wf_smu_failure_state == 0) {
376 		rc = fan_system->ops->set_value(fan_system, st->sys_setpoint);
377 		if (rc) {
378 			printk(KERN_WARNING "windfarm: Sys fan error %d\n",
379 			       rc);
380 			wf_smu_failure_state |= FAILURE_FAN;
381 		}
382 	}
383 	if (fan_hd && wf_smu_failure_state == 0) {
384 		rc = fan_hd->ops->set_value(fan_hd, st->hd_setpoint);
385 		if (rc) {
386 			printk(KERN_WARNING "windfarm: HD fan error %d\n",
387 			       rc);
388 			wf_smu_failure_state |= FAILURE_FAN;
389 		}
390 	}
391 }
392 
393 static void wf_smu_create_cpu_fans(void)
394 {
395 	struct wf_cpu_pid_param pid_param;
396 	const struct smu_sdbp_header *hdr;
397 	struct smu_sdbp_cpupiddata *piddata;
398 	struct smu_sdbp_fvt *fvt;
399 	s32 tmax, tdelta, maxpow, powadj;
400 
401 	/* First, locate the PID params in SMU SBD */
402 	hdr = smu_get_sdb_partition(SMU_SDB_CPUPIDDATA_ID, NULL);
403 	if (hdr == 0) {
404 		printk(KERN_WARNING "windfarm: CPU PID fan config not found "
405 		       "max fan speed\n");
406 		goto fail;
407 	}
408 	piddata = (struct smu_sdbp_cpupiddata *)&hdr[1];
409 
410 	/* Get the FVT params for operating point 0 (the only supported one
411 	 * for now) in order to get tmax
412 	 */
413 	hdr = smu_get_sdb_partition(SMU_SDB_FVT_ID, NULL);
414 	if (hdr) {
415 		fvt = (struct smu_sdbp_fvt *)&hdr[1];
416 		tmax = ((s32)fvt->maxtemp) << 16;
417 	} else
418 		tmax = 0x5e0000; /* 94 degree default */
419 
420 	/* Alloc & initialize state */
421 	wf_smu_cpu_fans = kmalloc(sizeof(struct wf_smu_cpu_fans_state),
422 				  GFP_KERNEL);
423 	if (wf_smu_cpu_fans == NULL)
424 		goto fail;
425        	wf_smu_cpu_fans->ticks = 1;
426 
427 	wf_smu_cpu_fans->scale = WF_SMU_CPU_FANS_SIBLING_SCALE;
428 	wf_smu_cpu_fans->offset = WF_SMU_CPU_FANS_SIBLING_OFFSET;
429 
430 	/* Fill PID params */
431 	pid_param.interval = WF_SMU_CPU_FANS_INTERVAL;
432 	pid_param.history_len = piddata->history_len;
433 	if (pid_param.history_len > WF_CPU_PID_MAX_HISTORY) {
434 		printk(KERN_WARNING "windfarm: History size overflow on "
435 		       "CPU control loop (%d)\n", piddata->history_len);
436 		pid_param.history_len = WF_CPU_PID_MAX_HISTORY;
437 	}
438 	pid_param.gd = piddata->gd;
439 	pid_param.gp = piddata->gp;
440 	pid_param.gr = piddata->gr / pid_param.history_len;
441 
442 	tdelta = ((s32)piddata->target_temp_delta) << 16;
443 	maxpow = ((s32)piddata->max_power) << 16;
444 	powadj = ((s32)piddata->power_adj) << 16;
445 
446 	pid_param.tmax = tmax;
447 	pid_param.ttarget = tmax - tdelta;
448 	pid_param.pmaxadj = maxpow - powadj;
449 
450 	pid_param.min = fan_cpu_main->ops->get_min(fan_cpu_main);
451 	pid_param.max = fan_cpu_main->ops->get_max(fan_cpu_main);
452 
453 	wf_cpu_pid_init(&wf_smu_cpu_fans->pid, &pid_param);
454 
455 	DBG("wf: CPU Fan control initialized.\n");
456 	DBG("    ttarged=%d.%03d, tmax=%d.%03d, min=%d RPM, max=%d RPM\n",
457 	    FIX32TOPRINT(pid_param.ttarget), FIX32TOPRINT(pid_param.tmax),
458 	    pid_param.min, pid_param.max);
459 
460 	return;
461 
462  fail:
463 	printk(KERN_WARNING "windfarm: CPU fan config not found\n"
464 	       "for this machine model, max fan speed\n");
465 
466 	if (cpufreq_clamp)
467 		wf_control_set_max(cpufreq_clamp);
468 	if (fan_cpu_main)
469 		wf_control_set_max(fan_cpu_main);
470 }
471 
472 static void wf_smu_cpu_fans_tick(struct wf_smu_cpu_fans_state *st)
473 {
474 	s32 new_setpoint, temp, power, systarget;
475 	int rc;
476 
477 	if (--st->ticks != 0) {
478 		if (wf_smu_readjust)
479 			goto readjust;
480 		return;
481 	}
482 	st->ticks = WF_SMU_CPU_FANS_INTERVAL;
483 
484 	rc = sensor_cpu_temp->ops->get_value(sensor_cpu_temp, &temp);
485 	if (rc) {
486 		printk(KERN_WARNING "windfarm: CPU temp sensor error %d\n",
487 		       rc);
488 		wf_smu_failure_state |= FAILURE_SENSOR;
489 		return;
490 	}
491 
492 	rc = sensor_cpu_power->ops->get_value(sensor_cpu_power, &power);
493 	if (rc) {
494 		printk(KERN_WARNING "windfarm: CPU power sensor error %d\n",
495 		       rc);
496 		wf_smu_failure_state |= FAILURE_SENSOR;
497 		return;
498 	}
499 
500 	DBG("wf_smu: CPU Fans tick ! CPU temp: %d.%03d, power: %d.%03d\n",
501 	    FIX32TOPRINT(temp), FIX32TOPRINT(power));
502 
503 #ifdef HACKED_OVERTEMP
504 	if (temp > 0x4a0000)
505 		wf_smu_failure_state |= FAILURE_OVERTEMP;
506 #else
507 	if (temp > st->pid.param.tmax)
508 		wf_smu_failure_state |= FAILURE_OVERTEMP;
509 #endif
510 	new_setpoint = wf_cpu_pid_run(&st->pid, power, temp);
511 
512 	DBG("wf_smu: new_setpoint: %d RPM\n", (int)new_setpoint);
513 
514 	systarget = wf_smu_sys_fans ? wf_smu_sys_fans->pid.target : 0;
515 	systarget = ((((s64)systarget) * (s64)st->scale) >> 12)
516 		+ st->offset;
517 	new_setpoint = max(new_setpoint, systarget);
518 	new_setpoint = max(new_setpoint, st->pid.param.min);
519 	new_setpoint = min(new_setpoint, st->pid.param.max);
520 
521 	DBG("wf_smu: adjusted setpoint: %d RPM\n", (int)new_setpoint);
522 
523 	if (st->cpu_setpoint == new_setpoint)
524 		return;
525 	st->cpu_setpoint = new_setpoint;
526  readjust:
527 	if (fan_cpu_main && wf_smu_failure_state == 0) {
528 		rc = fan_cpu_main->ops->set_value(fan_cpu_main,
529 						  st->cpu_setpoint);
530 		if (rc) {
531 			printk(KERN_WARNING "windfarm: CPU main fan"
532 			       " error %d\n", rc);
533 			wf_smu_failure_state |= FAILURE_FAN;
534 		}
535 	}
536 }
537 
538 /*
539  * ****** Setup / Init / Misc ... ******
540  *
541  */
542 
543 static void wf_smu_tick(void)
544 {
545 	unsigned int last_failure = wf_smu_failure_state;
546 	unsigned int new_failure;
547 
548 	if (!wf_smu_started) {
549 		DBG("wf: creating control loops !\n");
550 		wf_smu_create_sys_fans();
551 		wf_smu_create_cpu_fans();
552 		wf_smu_started = 1;
553 	}
554 
555 	/* Skipping ticks */
556 	if (wf_smu_skipping && --wf_smu_skipping)
557 		return;
558 
559 	wf_smu_failure_state = 0;
560 	if (wf_smu_sys_fans)
561 		wf_smu_sys_fans_tick(wf_smu_sys_fans);
562 	if (wf_smu_cpu_fans)
563 		wf_smu_cpu_fans_tick(wf_smu_cpu_fans);
564 
565 	wf_smu_readjust = 0;
566 	new_failure = wf_smu_failure_state & ~last_failure;
567 
568 	/* If entering failure mode, clamp cpufreq and ramp all
569 	 * fans to full speed.
570 	 */
571 	if (wf_smu_failure_state && !last_failure) {
572 		if (cpufreq_clamp)
573 			wf_control_set_max(cpufreq_clamp);
574 		if (fan_system)
575 			wf_control_set_max(fan_system);
576 		if (fan_cpu_main)
577 			wf_control_set_max(fan_cpu_main);
578 		if (fan_hd)
579 			wf_control_set_max(fan_hd);
580 	}
581 
582 	/* If leaving failure mode, unclamp cpufreq and readjust
583 	 * all fans on next iteration
584 	 */
585 	if (!wf_smu_failure_state && last_failure) {
586 		if (cpufreq_clamp)
587 			wf_control_set_min(cpufreq_clamp);
588 		wf_smu_readjust = 1;
589 	}
590 
591 	/* Overtemp condition detected, notify and start skipping a couple
592 	 * ticks to let the temperature go down
593 	 */
594 	if (new_failure & FAILURE_OVERTEMP) {
595 		wf_set_overtemp();
596 		wf_smu_skipping = 2;
597 	}
598 
599 	/* We only clear the overtemp condition if overtemp is cleared
600 	 * _and_ no other failure is present. Since a sensor error will
601 	 * clear the overtemp condition (can't measure temperature) at
602 	 * the control loop levels, but we don't want to keep it clear
603 	 * here in this case
604 	 */
605 	if (new_failure == 0 && last_failure & FAILURE_OVERTEMP)
606 		wf_clear_overtemp();
607 }
608 
609 static void wf_smu_new_control(struct wf_control *ct)
610 {
611 	if (wf_smu_all_controls_ok)
612 		return;
613 
614 	if (fan_cpu_main == NULL && !strcmp(ct->name, "cpu-fan")) {
615 		if (wf_get_control(ct) == 0)
616 			fan_cpu_main = ct;
617 	}
618 
619 	if (fan_system == NULL && !strcmp(ct->name, "system-fan")) {
620 		if (wf_get_control(ct) == 0)
621 			fan_system = ct;
622 	}
623 
624 	if (cpufreq_clamp == NULL && !strcmp(ct->name, "cpufreq-clamp")) {
625 		if (wf_get_control(ct) == 0)
626 			cpufreq_clamp = ct;
627 	}
628 
629 	/* Darwin property list says the HD fan is only for model ID
630 	 * 0, 1, 2 and 3
631 	 */
632 
633 	if (wf_smu_mach_model > 3) {
634 		if (fan_system && fan_cpu_main && cpufreq_clamp)
635 			wf_smu_all_controls_ok = 1;
636 		return;
637 	}
638 
639 	if (fan_hd == NULL && !strcmp(ct->name, "drive-bay-fan")) {
640 		if (wf_get_control(ct) == 0)
641 			fan_hd = ct;
642 	}
643 
644 	if (fan_system && fan_hd && fan_cpu_main && cpufreq_clamp)
645 		wf_smu_all_controls_ok = 1;
646 }
647 
648 static void wf_smu_new_sensor(struct wf_sensor *sr)
649 {
650 	if (wf_smu_all_sensors_ok)
651 		return;
652 
653 	if (sensor_cpu_power == NULL && !strcmp(sr->name, "cpu-power")) {
654 		if (wf_get_sensor(sr) == 0)
655 			sensor_cpu_power = sr;
656 	}
657 
658 	if (sensor_cpu_temp == NULL && !strcmp(sr->name, "cpu-temp")) {
659 		if (wf_get_sensor(sr) == 0)
660 			sensor_cpu_temp = sr;
661 	}
662 
663 	if (sensor_hd_temp == NULL && !strcmp(sr->name, "hd-temp")) {
664 		if (wf_get_sensor(sr) == 0)
665 			sensor_hd_temp = sr;
666 	}
667 
668 	if (sensor_cpu_power && sensor_cpu_temp && sensor_hd_temp)
669 		wf_smu_all_sensors_ok = 1;
670 }
671 
672 
673 static int wf_smu_notify(struct notifier_block *self,
674 			       unsigned long event, void *data)
675 {
676 	switch(event) {
677 	case WF_EVENT_NEW_CONTROL:
678 		DBG("wf: new control %s detected\n",
679 		    ((struct wf_control *)data)->name);
680 		wf_smu_new_control(data);
681 		wf_smu_readjust = 1;
682 		break;
683 	case WF_EVENT_NEW_SENSOR:
684 		DBG("wf: new sensor %s detected\n",
685 		    ((struct wf_sensor *)data)->name);
686 		wf_smu_new_sensor(data);
687 		break;
688 	case WF_EVENT_TICK:
689 		if (wf_smu_all_controls_ok && wf_smu_all_sensors_ok)
690 			wf_smu_tick();
691 	}
692 
693 	return 0;
694 }
695 
696 static struct notifier_block wf_smu_events = {
697 	.notifier_call	= wf_smu_notify,
698 };
699 
700 static int wf_init_pm(void)
701 {
702 	const struct smu_sdbp_header *hdr;
703 
704 	hdr = smu_get_sdb_partition(SMU_SDB_SENSORTREE_ID, NULL);
705 	if (hdr != 0) {
706 		struct smu_sdbp_sensortree *st =
707 			(struct smu_sdbp_sensortree *)&hdr[1];
708 		wf_smu_mach_model = st->model_id;
709 	}
710 
711 	printk(KERN_INFO "windfarm: Initializing for iMacG5 model ID %d\n",
712 	       wf_smu_mach_model);
713 
714 	return 0;
715 }
716 
717 static int wf_smu_probe(struct platform_device *ddev)
718 {
719 	wf_register_client(&wf_smu_events);
720 
721 	return 0;
722 }
723 
724 static int __devexit wf_smu_remove(struct platform_device *ddev)
725 {
726 	wf_unregister_client(&wf_smu_events);
727 
728 	/* XXX We don't have yet a guarantee that our callback isn't
729 	 * in progress when returning from wf_unregister_client, so
730 	 * we add an arbitrary delay. I'll have to fix that in the core
731 	 */
732 	msleep(1000);
733 
734 	/* Release all sensors */
735 	/* One more crappy race: I don't think we have any guarantee here
736 	 * that the attribute callback won't race with the sensor beeing
737 	 * disposed of, and I'm not 100% certain what best way to deal
738 	 * with that except by adding locks all over... I'll do that
739 	 * eventually but heh, who ever rmmod this module anyway ?
740 	 */
741 	if (sensor_cpu_power)
742 		wf_put_sensor(sensor_cpu_power);
743 	if (sensor_cpu_temp)
744 		wf_put_sensor(sensor_cpu_temp);
745 	if (sensor_hd_temp)
746 		wf_put_sensor(sensor_hd_temp);
747 
748 	/* Release all controls */
749 	if (fan_cpu_main)
750 		wf_put_control(fan_cpu_main);
751 	if (fan_hd)
752 		wf_put_control(fan_hd);
753 	if (fan_system)
754 		wf_put_control(fan_system);
755 	if (cpufreq_clamp)
756 		wf_put_control(cpufreq_clamp);
757 
758 	/* Destroy control loops state structures */
759 	kfree(wf_smu_sys_fans);
760 	kfree(wf_smu_cpu_fans);
761 
762 	return 0;
763 }
764 
765 static struct platform_driver wf_smu_driver = {
766         .probe = wf_smu_probe,
767         .remove = __devexit_p(wf_smu_remove),
768 	.driver = {
769 		.name = "windfarm",
770 		.owner	= THIS_MODULE,
771 	},
772 };
773 
774 
775 static int __init wf_smu_init(void)
776 {
777 	int rc = -ENODEV;
778 
779 	if (of_machine_is_compatible("PowerMac8,1") ||
780 	    of_machine_is_compatible("PowerMac8,2"))
781 		rc = wf_init_pm();
782 
783 	if (rc == 0) {
784 #ifdef MODULE
785 		request_module("windfarm_smu_controls");
786 		request_module("windfarm_smu_sensors");
787 		request_module("windfarm_lm75_sensor");
788 		request_module("windfarm_cpufreq_clamp");
789 
790 #endif /* MODULE */
791 		platform_driver_register(&wf_smu_driver);
792 	}
793 
794 	return rc;
795 }
796 
797 static void __exit wf_smu_exit(void)
798 {
799 
800 	platform_driver_unregister(&wf_smu_driver);
801 }
802 
803 
804 module_init(wf_smu_init);
805 module_exit(wf_smu_exit);
806 
807 MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
808 MODULE_DESCRIPTION("Thermal control logic for iMac G5");
809 MODULE_LICENSE("GPL");
810 MODULE_ALIAS("platform:windfarm");
811