1 // SPDX-License-Identifier: GPL-2.0-only
3 * Windfarm PowerMac thermal control. iMac G5
5 * (c) Copyright 2005 Benjamin Herrenschmidt, IBM Corp.
6 * <benh@kernel.crashing.org>
8 * The algorithm used is the PID control algorithm, used the same
9 * way the published Darwin code does, using the same values that
10 * are present in the Darwin 8.2 snapshot property lists (note however
11 * that none of the code has been re-used, it's a complete re-implementation
13 * The various control loops found in Darwin config file are:
15 * PowerMac8,1 and PowerMac8,2
16 * ===========================
18 * System Fans control loop. Different based on models. In addition to the
19 * usual PID algorithm, the control loop gets 2 additional pairs of linear
20 * scaling factors (scale/offsets) expressed as 4.12 fixed point values
21 * signed offset, unsigned scale)
23 * The targets are modified such as:
24 * - the linked control (second control) gets the target value as-is
25 * (typically the drive fan)
26 * - the main control (first control) gets the target value scaled with
27 * the first pair of factors, and is then modified as below
28 * - the value of the target of the CPU Fan control loop is retrieved,
29 * scaled with the second pair of factors, and the max of that and
30 * the scaled target is applied to the main control.
33 * controls : system-fan, drive-bay-fan
35 * PID params : G_d = 0x15400000
39 * Input target = 0x3a0000
41 * linear-factors : offset = 0xff38 scale = 0x0ccd
42 * offset = 0x0208 scale = 0x07ae
45 * controls : system-fan, drive-bay-fan
47 * PID params : G_d = 0x08e00000
51 * Input target = 0x350000
53 * linear-factors : offset = 0xff38 scale = 0x0ccd
54 * offset = 0x0000 scale = 0x0000
57 * controls : system-fan
59 * PID params : G_d = 0x15400000
63 * Input target = 0x3a0000
65 * linear-factors : offset = 0x0000 scale = 0x1000
66 * offset = 0x0091 scale = 0x0bae
68 * CPU Fan control loop. The loop is identical for all models. it
69 * has an additional pair of scaling factor. This is used to scale the
70 * systems fan control loop target result (the one before it gets scaled
71 * by the System Fans control loop itself). Then, the max value of the
72 * calculated target value and system fan value is sent to the fans
75 * sensors : cpu-temp cpu-power
76 * PID params : From SMU sdb partition
77 * linear-factors : offset = 0xfb50 scale = 0x1000
79 * CPU Slew control loop. Not implemented. The cpufreq driver in linux is
80 * completely separate for now, though we could find a way to link it, either
81 * as a client reacting to overtemp notifications, or directling monitoring
84 * WARNING ! The CPU control loop requires the CPU tmax for the current
85 * operating point. However, we currently are completely separated from
86 * the cpufreq driver and thus do not know what the current operating
87 * point is. Fortunately, we also do not have any hardware supporting anything
88 * but operating point 0 at the moment, thus we just peek that value directly
89 * from the SDB partition. If we ever end up with actually slewing the system
90 * clock and thus changing operating points, we'll have to find a way to
91 * communicate with the CPU freq driver;
94 #include <linux/types.h>
95 #include <linux/errno.h>
96 #include <linux/kernel.h>
97 #include <linux/delay.h>
98 #include <linux/slab.h>
99 #include <linux/init.h>
100 #include <linux/spinlock.h>
101 #include <linux/wait.h>
102 #include <linux/kmod.h>
103 #include <linux/device.h>
104 #include <linux/platform_device.h>
105 #include <asm/prom.h>
106 #include <asm/machdep.h>
108 #include <asm/sections.h>
111 #include "windfarm.h"
112 #include "windfarm_pid.h"
114 #define VERSION "0.4"
119 #define DBG(args...) printk(args)
121 #define DBG(args...) do { } while(0)
124 /* define this to force CPU overtemp to 74 degree, useful for testing
127 #undef HACKED_OVERTEMP
129 static int wf_smu_mach_model
; /* machine model id */
131 /* Controls & sensors */
132 static struct wf_sensor
*sensor_cpu_power
;
133 static struct wf_sensor
*sensor_cpu_temp
;
134 static struct wf_sensor
*sensor_hd_temp
;
135 static struct wf_control
*fan_cpu_main
;
136 static struct wf_control
*fan_hd
;
137 static struct wf_control
*fan_system
;
138 static struct wf_control
*cpufreq_clamp
;
140 /* Set to kick the control loop into life */
141 static int wf_smu_all_controls_ok
, wf_smu_all_sensors_ok
;
142 static bool wf_smu_started
;
144 /* Failure handling.. could be nicer */
145 #define FAILURE_FAN 0x01
146 #define FAILURE_SENSOR 0x02
147 #define FAILURE_OVERTEMP 0x04
149 static unsigned int wf_smu_failure_state
;
150 static int wf_smu_readjust
, wf_smu_skipping
;
151 static bool wf_smu_overtemp
;
154 * ****** System Fans Control Loop ******
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.
162 struct wf_smu_sys_fans_param
{
173 #define WF_SMU_SYS_FANS_INTERVAL 5
174 #define WF_SMU_SYS_FANS_HISTORY_SIZE 2
176 /* State data used by the system fans control loop
178 struct wf_smu_sys_fans_state
{
186 struct wf_pid_state pid
;
190 * Configs for SMU System Fan control loop
192 static struct wf_smu_sys_fans_param wf_smu_sys_all_params
[] = {
230 #define WF_SMU_SYS_FANS_NUM_CONFIGS ARRAY_SIZE(wf_smu_sys_all_params)
232 static struct wf_smu_sys_fans_state
*wf_smu_sys_fans
;
235 * ****** CPU Fans Control Loop ******
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
245 /* State data used by the cpu fans control loop
247 struct wf_smu_cpu_fans_state
{
252 struct wf_cpu_pid_state pid
;
255 static struct wf_smu_cpu_fans_state
*wf_smu_cpu_fans
;
260 * ***** Implementation *****
264 static void wf_smu_create_sys_fans(void)
266 struct wf_smu_sys_fans_param
*param
= NULL
;
267 struct wf_pid_param pid_param
;
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
];
277 /* No params found, put fans to max */
279 printk(KERN_WARNING
"windfarm: System fan config not found "
280 "for this machine model, max fan speed\n");
284 /* Alloc & initialize state */
285 wf_smu_sys_fans
= kmalloc(sizeof(struct wf_smu_sys_fans_state
),
287 if (wf_smu_sys_fans
== NULL
) {
288 printk(KERN_WARNING
"windfarm: Memory allocation error"
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
;
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
= wf_control_get_min(fan_system
);
306 pid_param
.max
= wf_control_get_max(fan_system
);
309 max(pid_param
.min
, wf_control_get_min(fan_hd
));
311 min(pid_param
.max
, wf_control_get_max(fan_hd
));
313 wf_pid_init(&wf_smu_sys_fans
->pid
, &pid_param
);
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
);
323 wf_control_set_max(fan_system
);
325 wf_control_set_max(fan_hd
);
328 static void wf_smu_sys_fans_tick(struct wf_smu_sys_fans_state
*st
)
330 s32 new_setpoint
, temp
, scaled
, cputarget
;
333 if (--st
->ticks
!= 0) {
338 st
->ticks
= WF_SMU_SYS_FANS_INTERVAL
;
340 rc
= wf_sensor_get(sensor_hd_temp
, &temp
);
342 printk(KERN_WARNING
"windfarm: HD temp sensor error %d\n",
344 wf_smu_failure_state
|= FAILURE_SENSOR
;
348 DBG("wf_smu: System Fans tick ! HD temp: %d.%03d\n",
351 if (temp
> (st
->pid
.param
.itarget
+ 0x50000))
352 wf_smu_failure_state
|= FAILURE_OVERTEMP
;
354 new_setpoint
= wf_pid_run(&st
->pid
, temp
);
356 DBG("wf_smu: new_setpoint: %d RPM\n", (int)new_setpoint
);
358 scaled
= ((((s64
)new_setpoint
) * (s64
)st
->scale0
) >> 12) + st
->offset0
;
360 DBG("wf_smu: scaled setpoint: %d RPM\n", (int)scaled
);
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
);
368 DBG("wf_smu: adjusted setpoint: %d RPM\n", (int)scaled
);
370 if (st
->sys_setpoint
== scaled
&& new_setpoint
== st
->hd_setpoint
)
372 st
->sys_setpoint
= scaled
;
373 st
->hd_setpoint
= new_setpoint
;
375 if (fan_system
&& wf_smu_failure_state
== 0) {
376 rc
= wf_control_set(fan_system
, st
->sys_setpoint
);
378 printk(KERN_WARNING
"windfarm: Sys fan error %d\n",
380 wf_smu_failure_state
|= FAILURE_FAN
;
383 if (fan_hd
&& wf_smu_failure_state
== 0) {
384 rc
= wf_control_set(fan_hd
, st
->hd_setpoint
);
386 printk(KERN_WARNING
"windfarm: HD fan error %d\n",
388 wf_smu_failure_state
|= FAILURE_FAN
;
393 static void wf_smu_create_cpu_fans(void)
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
;
401 /* First, locate the PID params in SMU SBD */
402 hdr
= smu_get_sdb_partition(SMU_SDB_CPUPIDDATA_ID
, NULL
);
404 printk(KERN_WARNING
"windfarm: CPU PID fan config not found "
408 piddata
= (struct smu_sdbp_cpupiddata
*)&hdr
[1];
410 /* Get the FVT params for operating point 0 (the only supported one
411 * for now) in order to get tmax
413 hdr
= smu_get_sdb_partition(SMU_SDB_FVT_ID
, NULL
);
415 fvt
= (struct smu_sdbp_fvt
*)&hdr
[1];
416 tmax
= ((s32
)fvt
->maxtemp
) << 16;
418 tmax
= 0x5e0000; /* 94 degree default */
420 /* Alloc & initialize state */
421 wf_smu_cpu_fans
= kmalloc(sizeof(struct wf_smu_cpu_fans_state
),
423 if (wf_smu_cpu_fans
== NULL
)
425 wf_smu_cpu_fans
->ticks
= 1;
427 wf_smu_cpu_fans
->scale
= WF_SMU_CPU_FANS_SIBLING_SCALE
;
428 wf_smu_cpu_fans
->offset
= WF_SMU_CPU_FANS_SIBLING_OFFSET
;
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
;
438 pid_param
.gd
= piddata
->gd
;
439 pid_param
.gp
= piddata
->gp
;
440 pid_param
.gr
= piddata
->gr
/ pid_param
.history_len
;
442 tdelta
= ((s32
)piddata
->target_temp_delta
) << 16;
443 maxpow
= ((s32
)piddata
->max_power
) << 16;
444 powadj
= ((s32
)piddata
->power_adj
) << 16;
446 pid_param
.tmax
= tmax
;
447 pid_param
.ttarget
= tmax
- tdelta
;
448 pid_param
.pmaxadj
= maxpow
- powadj
;
450 pid_param
.min
= wf_control_get_min(fan_cpu_main
);
451 pid_param
.max
= wf_control_get_max(fan_cpu_main
);
453 wf_cpu_pid_init(&wf_smu_cpu_fans
->pid
, &pid_param
);
455 DBG("wf: CPU Fan control initialized.\n");
456 DBG(" ttarget=%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
);
463 printk(KERN_WARNING
"windfarm: CPU fan config not found\n"
464 "for this machine model, max fan speed\n");
467 wf_control_set_max(cpufreq_clamp
);
469 wf_control_set_max(fan_cpu_main
);
472 static void wf_smu_cpu_fans_tick(struct wf_smu_cpu_fans_state
*st
)
474 s32 new_setpoint
, temp
, power
, systarget
;
477 if (--st
->ticks
!= 0) {
482 st
->ticks
= WF_SMU_CPU_FANS_INTERVAL
;
484 rc
= wf_sensor_get(sensor_cpu_temp
, &temp
);
486 printk(KERN_WARNING
"windfarm: CPU temp sensor error %d\n",
488 wf_smu_failure_state
|= FAILURE_SENSOR
;
492 rc
= wf_sensor_get(sensor_cpu_power
, &power
);
494 printk(KERN_WARNING
"windfarm: CPU power sensor error %d\n",
496 wf_smu_failure_state
|= FAILURE_SENSOR
;
500 DBG("wf_smu: CPU Fans tick ! CPU temp: %d.%03d, power: %d.%03d\n",
501 FIX32TOPRINT(temp
), FIX32TOPRINT(power
));
503 #ifdef HACKED_OVERTEMP
505 wf_smu_failure_state
|= FAILURE_OVERTEMP
;
507 if (temp
> st
->pid
.param
.tmax
)
508 wf_smu_failure_state
|= FAILURE_OVERTEMP
;
510 new_setpoint
= wf_cpu_pid_run(&st
->pid
, power
, temp
);
512 DBG("wf_smu: new_setpoint: %d RPM\n", (int)new_setpoint
);
514 systarget
= wf_smu_sys_fans
? wf_smu_sys_fans
->pid
.target
: 0;
515 systarget
= ((((s64
)systarget
) * (s64
)st
->scale
) >> 12)
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
);
521 DBG("wf_smu: adjusted setpoint: %d RPM\n", (int)new_setpoint
);
523 if (st
->cpu_setpoint
== new_setpoint
)
525 st
->cpu_setpoint
= new_setpoint
;
527 if (fan_cpu_main
&& wf_smu_failure_state
== 0) {
528 rc
= wf_control_set(fan_cpu_main
, st
->cpu_setpoint
);
530 printk(KERN_WARNING
"windfarm: CPU main fan"
532 wf_smu_failure_state
|= FAILURE_FAN
;
538 * ****** Setup / Init / Misc ... ******
542 static void wf_smu_tick(void)
544 unsigned int last_failure
= wf_smu_failure_state
;
545 unsigned int new_failure
;
547 if (!wf_smu_started
) {
548 DBG("wf: creating control loops !\n");
549 wf_smu_create_sys_fans();
550 wf_smu_create_cpu_fans();
551 wf_smu_started
= true;
555 if (wf_smu_skipping
&& --wf_smu_skipping
)
558 wf_smu_failure_state
= 0;
560 wf_smu_sys_fans_tick(wf_smu_sys_fans
);
562 wf_smu_cpu_fans_tick(wf_smu_cpu_fans
);
565 new_failure
= wf_smu_failure_state
& ~last_failure
;
567 /* If entering failure mode, clamp cpufreq and ramp all
568 * fans to full speed.
570 if (wf_smu_failure_state
&& !last_failure
) {
572 wf_control_set_max(cpufreq_clamp
);
574 wf_control_set_max(fan_system
);
576 wf_control_set_max(fan_cpu_main
);
578 wf_control_set_max(fan_hd
);
581 /* If leaving failure mode, unclamp cpufreq and readjust
582 * all fans on next iteration
584 if (!wf_smu_failure_state
&& last_failure
) {
586 wf_control_set_min(cpufreq_clamp
);
590 /* Overtemp condition detected, notify and start skipping a couple
591 * ticks to let the temperature go down
593 if (new_failure
& FAILURE_OVERTEMP
) {
596 wf_smu_overtemp
= true;
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
605 if (!wf_smu_failure_state
&& wf_smu_overtemp
) {
607 wf_smu_overtemp
= false;
611 static void wf_smu_new_control(struct wf_control
*ct
)
613 if (wf_smu_all_controls_ok
)
616 if (fan_cpu_main
== NULL
&& !strcmp(ct
->name
, "cpu-fan")) {
617 if (wf_get_control(ct
) == 0)
621 if (fan_system
== NULL
&& !strcmp(ct
->name
, "system-fan")) {
622 if (wf_get_control(ct
) == 0)
626 if (cpufreq_clamp
== NULL
&& !strcmp(ct
->name
, "cpufreq-clamp")) {
627 if (wf_get_control(ct
) == 0)
631 /* Darwin property list says the HD fan is only for model ID
635 if (wf_smu_mach_model
> 3) {
636 if (fan_system
&& fan_cpu_main
&& cpufreq_clamp
)
637 wf_smu_all_controls_ok
= 1;
641 if (fan_hd
== NULL
&& !strcmp(ct
->name
, "drive-bay-fan")) {
642 if (wf_get_control(ct
) == 0)
646 if (fan_system
&& fan_hd
&& fan_cpu_main
&& cpufreq_clamp
)
647 wf_smu_all_controls_ok
= 1;
650 static void wf_smu_new_sensor(struct wf_sensor
*sr
)
652 if (wf_smu_all_sensors_ok
)
655 if (sensor_cpu_power
== NULL
&& !strcmp(sr
->name
, "cpu-power")) {
656 if (wf_get_sensor(sr
) == 0)
657 sensor_cpu_power
= sr
;
660 if (sensor_cpu_temp
== NULL
&& !strcmp(sr
->name
, "cpu-temp")) {
661 if (wf_get_sensor(sr
) == 0)
662 sensor_cpu_temp
= sr
;
665 if (sensor_hd_temp
== NULL
&& !strcmp(sr
->name
, "hd-temp")) {
666 if (wf_get_sensor(sr
) == 0)
670 if (sensor_cpu_power
&& sensor_cpu_temp
&& sensor_hd_temp
)
671 wf_smu_all_sensors_ok
= 1;
675 static int wf_smu_notify(struct notifier_block
*self
,
676 unsigned long event
, void *data
)
679 case WF_EVENT_NEW_CONTROL
:
680 DBG("wf: new control %s detected\n",
681 ((struct wf_control
*)data
)->name
);
682 wf_smu_new_control(data
);
685 case WF_EVENT_NEW_SENSOR
:
686 DBG("wf: new sensor %s detected\n",
687 ((struct wf_sensor
*)data
)->name
);
688 wf_smu_new_sensor(data
);
691 if (wf_smu_all_controls_ok
&& wf_smu_all_sensors_ok
)
698 static struct notifier_block wf_smu_events
= {
699 .notifier_call
= wf_smu_notify
,
702 static int wf_init_pm(void)
704 const struct smu_sdbp_header
*hdr
;
706 hdr
= smu_get_sdb_partition(SMU_SDB_SENSORTREE_ID
, NULL
);
708 struct smu_sdbp_sensortree
*st
=
709 (struct smu_sdbp_sensortree
*)&hdr
[1];
710 wf_smu_mach_model
= st
->model_id
;
713 printk(KERN_INFO
"windfarm: Initializing for iMacG5 model ID %d\n",
719 static int wf_smu_probe(struct platform_device
*ddev
)
721 wf_register_client(&wf_smu_events
);
726 static int wf_smu_remove(struct platform_device
*ddev
)
728 wf_unregister_client(&wf_smu_events
);
730 /* XXX We don't have yet a guarantee that our callback isn't
731 * in progress when returning from wf_unregister_client, so
732 * we add an arbitrary delay. I'll have to fix that in the core
736 /* Release all sensors */
737 /* One more crappy race: I don't think we have any guarantee here
738 * that the attribute callback won't race with the sensor beeing
739 * disposed of, and I'm not 100% certain what best way to deal
740 * with that except by adding locks all over... I'll do that
741 * eventually but heh, who ever rmmod this module anyway ?
743 if (sensor_cpu_power
)
744 wf_put_sensor(sensor_cpu_power
);
746 wf_put_sensor(sensor_cpu_temp
);
748 wf_put_sensor(sensor_hd_temp
);
750 /* Release all controls */
752 wf_put_control(fan_cpu_main
);
754 wf_put_control(fan_hd
);
756 wf_put_control(fan_system
);
758 wf_put_control(cpufreq_clamp
);
760 /* Destroy control loops state structures */
761 kfree(wf_smu_sys_fans
);
762 kfree(wf_smu_cpu_fans
);
767 static struct platform_driver wf_smu_driver
= {
768 .probe
= wf_smu_probe
,
769 .remove
= wf_smu_remove
,
776 static int __init
wf_smu_init(void)
780 if (of_machine_is_compatible("PowerMac8,1") ||
781 of_machine_is_compatible("PowerMac8,2"))
786 request_module("windfarm_smu_controls");
787 request_module("windfarm_smu_sensors");
788 request_module("windfarm_lm75_sensor");
789 request_module("windfarm_cpufreq_clamp");
792 platform_driver_register(&wf_smu_driver
);
798 static void __exit
wf_smu_exit(void)
801 platform_driver_unregister(&wf_smu_driver
);
805 module_init(wf_smu_init
);
806 module_exit(wf_smu_exit
);
808 MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
809 MODULE_DESCRIPTION("Thermal control logic for iMac G5");
810 MODULE_LICENSE("GPL");
811 MODULE_ALIAS("platform:windfarm");