1 /*
2  * Windfarm PowerMac thermal control. FCU fan control
3  *
4  * Copyright 2012 Benjamin Herrenschmidt, IBM Corp.
5  *
6  * Released under the term of the GNU GPL v2.
7  */
8 #undef DEBUG
9 
10 #include <linux/types.h>
11 #include <linux/errno.h>
12 #include <linux/kernel.h>
13 #include <linux/delay.h>
14 #include <linux/slab.h>
15 #include <linux/init.h>
16 #include <linux/wait.h>
17 #include <linux/i2c.h>
18 #include <asm/prom.h>
19 #include <asm/machdep.h>
20 #include <asm/io.h>
21 #include <asm/sections.h>
22 
23 #include "windfarm.h"
24 #include "windfarm_mpu.h"
25 
26 #define VERSION "1.0"
27 
28 #ifdef DEBUG
29 #define DBG(args...)	printk(args)
30 #else
31 #define DBG(args...)	do { } while(0)
32 #endif
33 
34 /*
35  * This option is "weird" :) Basically, if you define this to 1
36  * the control loop for the RPMs fans (not PWMs) will apply the
37  * correction factor obtained from the PID to the actual RPM
38  * speed read from the FCU.
39  *
40  * If you define the below constant to 0, then it will be
41  * applied to the setpoint RPM speed, that is basically the
42  * speed we proviously "asked" for.
43  *
44  * I'm using 0 for now which is what therm_pm72 used to do and
45  * what Darwin -apparently- does based on observed behaviour.
46  */
47 #define RPM_PID_USE_ACTUAL_SPEED	0
48 
49 /* Default min/max for pumps */
50 #define CPU_PUMP_OUTPUT_MAX		3200
51 #define CPU_PUMP_OUTPUT_MIN		1250
52 
53 #define FCU_FAN_RPM		0
54 #define FCU_FAN_PWM		1
55 
56 struct wf_fcu_priv {
57 	struct kref		ref;
58 	struct i2c_client	*i2c;
59 	struct mutex		lock;
60 	struct list_head	fan_list;
61 	int			rpm_shift;
62 };
63 
64 struct wf_fcu_fan {
65 	struct list_head	link;
66 	int			id;
67 	s32			min, max, target;
68 	struct wf_fcu_priv	*fcu_priv;
69 	struct wf_control	ctrl;
70 };
71 
72 static void wf_fcu_release(struct kref *ref)
73 {
74 	struct wf_fcu_priv *pv = container_of(ref, struct wf_fcu_priv, ref);
75 
76 	kfree(pv);
77 }
78 
79 static void wf_fcu_fan_release(struct wf_control *ct)
80 {
81 	struct wf_fcu_fan *fan = ct->priv;
82 
83 	kref_put(&fan->fcu_priv->ref, wf_fcu_release);
84 	kfree(fan);
85 }
86 
87 static int wf_fcu_read_reg(struct wf_fcu_priv *pv, int reg,
88 			   unsigned char *buf, int nb)
89 {
90 	int tries, nr, nw;
91 
92 	mutex_lock(&pv->lock);
93 
94 	buf[0] = reg;
95 	tries = 0;
96 	for (;;) {
97 		nw = i2c_master_send(pv->i2c, buf, 1);
98 		if (nw > 0 || (nw < 0 && nw != -EIO) || tries >= 100)
99 			break;
100 		msleep(10);
101 		++tries;
102 	}
103 	if (nw <= 0) {
104 		pr_err("Failure writing address to FCU: %d", nw);
105 		nr = nw;
106 		goto bail;
107 	}
108 	tries = 0;
109 	for (;;) {
110 		nr = i2c_master_recv(pv->i2c, buf, nb);
111 		if (nr > 0 || (nr < 0 && nr != -ENODEV) || tries >= 100)
112 			break;
113 		msleep(10);
114 		++tries;
115 	}
116 	if (nr <= 0)
117 		pr_err("wf_fcu: Failure reading data from FCU: %d", nw);
118  bail:
119 	mutex_unlock(&pv->lock);
120 	return nr;
121 }
122 
123 static int wf_fcu_write_reg(struct wf_fcu_priv *pv, int reg,
124 			    const unsigned char *ptr, int nb)
125 {
126 	int tries, nw;
127 	unsigned char buf[16];
128 
129 	buf[0] = reg;
130 	memcpy(buf+1, ptr, nb);
131 	++nb;
132 	tries = 0;
133 	for (;;) {
134 		nw = i2c_master_send(pv->i2c, buf, nb);
135 		if (nw > 0 || (nw < 0 && nw != -EIO) || tries >= 100)
136 			break;
137 		msleep(10);
138 		++tries;
139 	}
140 	if (nw < 0)
141 		pr_err("wf_fcu: Failure writing to FCU: %d", nw);
142 	return nw;
143 }
144 
145 static int wf_fcu_fan_set_rpm(struct wf_control *ct, s32 value)
146 {
147 	struct wf_fcu_fan *fan = ct->priv;
148 	struct wf_fcu_priv *pv = fan->fcu_priv;
149 	int rc, shift = pv->rpm_shift;
150 	unsigned char buf[2];
151 
152 	if (value < fan->min)
153 		value = fan->min;
154 	if (value > fan->max)
155 		value = fan->max;
156 
157 	fan->target = value;
158 
159 	buf[0] = value >> (8 - shift);
160 	buf[1] = value << shift;
161 	rc = wf_fcu_write_reg(pv, 0x10 + (fan->id * 2), buf, 2);
162 	if (rc < 0)
163 		return -EIO;
164 	return 0;
165 }
166 
167 static int wf_fcu_fan_get_rpm(struct wf_control *ct, s32 *value)
168 {
169 	struct wf_fcu_fan *fan = ct->priv;
170 	struct wf_fcu_priv *pv = fan->fcu_priv;
171 	int rc, reg_base, shift = pv->rpm_shift;
172 	unsigned char failure;
173 	unsigned char active;
174 	unsigned char buf[2];
175 
176 	rc = wf_fcu_read_reg(pv, 0xb, &failure, 1);
177 	if (rc != 1)
178 		return -EIO;
179 	if ((failure & (1 << fan->id)) != 0)
180 		return -EFAULT;
181 	rc = wf_fcu_read_reg(pv, 0xd, &active, 1);
182 	if (rc != 1)
183 		return -EIO;
184 	if ((active & (1 << fan->id)) == 0)
185 		return -ENXIO;
186 
187 	/* Programmed value or real current speed */
188 #if RPM_PID_USE_ACTUAL_SPEED
189 	reg_base = 0x11;
190 #else
191 	reg_base = 0x10;
192 #endif
193 	rc = wf_fcu_read_reg(pv, reg_base + (fan->id * 2), buf, 2);
194 	if (rc != 2)
195 		return -EIO;
196 
197 	*value = (buf[0] << (8 - shift)) | buf[1] >> shift;
198 
199 	return 0;
200 }
201 
202 static int wf_fcu_fan_set_pwm(struct wf_control *ct, s32 value)
203 {
204 	struct wf_fcu_fan *fan = ct->priv;
205 	struct wf_fcu_priv *pv = fan->fcu_priv;
206 	unsigned char buf[2];
207 	int rc;
208 
209 	if (value < fan->min)
210 		value = fan->min;
211 	if (value > fan->max)
212 		value = fan->max;
213 
214 	fan->target = value;
215 
216 	value = (value * 2559) / 1000;
217 	buf[0] = value;
218 	rc = wf_fcu_write_reg(pv, 0x30 + (fan->id * 2), buf, 1);
219 	if (rc < 0)
220 		return -EIO;
221 	return 0;
222 }
223 
224 static int wf_fcu_fan_get_pwm(struct wf_control *ct, s32 *value)
225 {
226 	struct wf_fcu_fan *fan = ct->priv;
227 	struct wf_fcu_priv *pv = fan->fcu_priv;
228 	unsigned char failure;
229 	unsigned char active;
230 	unsigned char buf[2];
231 	int rc;
232 
233 	rc = wf_fcu_read_reg(pv, 0x2b, &failure, 1);
234 	if (rc != 1)
235 		return -EIO;
236 	if ((failure & (1 << fan->id)) != 0)
237 		return -EFAULT;
238 	rc = wf_fcu_read_reg(pv, 0x2d, &active, 1);
239 	if (rc != 1)
240 		return -EIO;
241 	if ((active & (1 << fan->id)) == 0)
242 		return -ENXIO;
243 
244 	rc = wf_fcu_read_reg(pv, 0x30 + (fan->id * 2), buf, 1);
245 	if (rc != 1)
246 		return -EIO;
247 
248 	*value = (((s32)buf[0]) * 1000) / 2559;
249 
250 	return 0;
251 }
252 
253 static s32 wf_fcu_fan_min(struct wf_control *ct)
254 {
255 	struct wf_fcu_fan *fan = ct->priv;
256 
257 	return fan->min;
258 }
259 
260 static s32 wf_fcu_fan_max(struct wf_control *ct)
261 {
262 	struct wf_fcu_fan *fan = ct->priv;
263 
264 	return fan->max;
265 }
266 
267 static const struct wf_control_ops wf_fcu_fan_rpm_ops = {
268 	.set_value	= wf_fcu_fan_set_rpm,
269 	.get_value	= wf_fcu_fan_get_rpm,
270 	.get_min	= wf_fcu_fan_min,
271 	.get_max	= wf_fcu_fan_max,
272 	.release	= wf_fcu_fan_release,
273 	.owner		= THIS_MODULE,
274 };
275 
276 static const struct wf_control_ops wf_fcu_fan_pwm_ops = {
277 	.set_value	= wf_fcu_fan_set_pwm,
278 	.get_value	= wf_fcu_fan_get_pwm,
279 	.get_min	= wf_fcu_fan_min,
280 	.get_max	= wf_fcu_fan_max,
281 	.release	= wf_fcu_fan_release,
282 	.owner		= THIS_MODULE,
283 };
284 
285 static void wf_fcu_get_pump_minmax(struct wf_fcu_fan *fan)
286 {
287 	const struct mpu_data *mpu = wf_get_mpu(0);
288 	u16 pump_min = 0, pump_max = 0xffff;
289 	u16 tmp[4];
290 
291 	/* Try to fetch pumps min/max infos from eeprom */
292 	if (mpu) {
293 		memcpy(&tmp, mpu->processor_part_num, 8);
294 		if (tmp[0] != 0xffff && tmp[1] != 0xffff) {
295 			pump_min = max(pump_min, tmp[0]);
296 			pump_max = min(pump_max, tmp[1]);
297 		}
298 		if (tmp[2] != 0xffff && tmp[3] != 0xffff) {
299 			pump_min = max(pump_min, tmp[2]);
300 			pump_max = min(pump_max, tmp[3]);
301 		}
302 	}
303 
304 	/* Double check the values, this _IS_ needed as the EEPROM on
305 	 * some dual 2.5Ghz G5s seem, at least, to have both min & max
306 	 * same to the same value ... (grrrr)
307 	 */
308 	if (pump_min == pump_max || pump_min == 0 || pump_max == 0xffff) {
309 		pump_min = CPU_PUMP_OUTPUT_MIN;
310 		pump_max = CPU_PUMP_OUTPUT_MAX;
311 	}
312 
313 	fan->min = pump_min;
314 	fan->max = pump_max;
315 
316 	DBG("wf_fcu: pump min/max for %s set to: [%d..%d] RPM\n",
317 	    fan->ctrl.name, pump_min, pump_max);
318 }
319 
320 static void wf_fcu_get_rpmfan_minmax(struct wf_fcu_fan *fan)
321 {
322 	struct wf_fcu_priv *pv = fan->fcu_priv;
323 	const struct mpu_data *mpu0 = wf_get_mpu(0);
324 	const struct mpu_data *mpu1 = wf_get_mpu(1);
325 
326 	/* Default */
327 	fan->min = 2400 >> pv->rpm_shift;
328 	fan->max = 56000 >> pv->rpm_shift;
329 
330 	/* CPU fans have min/max in MPU */
331 	if (mpu0 && !strcmp(fan->ctrl.name, "cpu-front-fan-0")) {
332 		fan->min = max(fan->min, (s32)mpu0->rminn_intake_fan);
333 		fan->max = min(fan->max, (s32)mpu0->rmaxn_intake_fan);
334 		goto bail;
335 	}
336 	if (mpu1 && !strcmp(fan->ctrl.name, "cpu-front-fan-1")) {
337 		fan->min = max(fan->min, (s32)mpu1->rminn_intake_fan);
338 		fan->max = min(fan->max, (s32)mpu1->rmaxn_intake_fan);
339 		goto bail;
340 	}
341 	if (mpu0 && !strcmp(fan->ctrl.name, "cpu-rear-fan-0")) {
342 		fan->min = max(fan->min, (s32)mpu0->rminn_exhaust_fan);
343 		fan->max = min(fan->max, (s32)mpu0->rmaxn_exhaust_fan);
344 		goto bail;
345 	}
346 	if (mpu1 && !strcmp(fan->ctrl.name, "cpu-rear-fan-1")) {
347 		fan->min = max(fan->min, (s32)mpu1->rminn_exhaust_fan);
348 		fan->max = min(fan->max, (s32)mpu1->rmaxn_exhaust_fan);
349 		goto bail;
350 	}
351 	/* Rackmac variants, we just use mpu0 intake */
352 	if (!strncmp(fan->ctrl.name, "cpu-fan", 7)) {
353 		fan->min = max(fan->min, (s32)mpu0->rminn_intake_fan);
354 		fan->max = min(fan->max, (s32)mpu0->rmaxn_intake_fan);
355 		goto bail;
356 	}
357  bail:
358 	DBG("wf_fcu: fan min/max for %s set to: [%d..%d] RPM\n",
359 	    fan->ctrl.name, fan->min, fan->max);
360 }
361 
362 static void wf_fcu_add_fan(struct wf_fcu_priv *pv, const char *name,
363 			   int type, int id)
364 {
365 	struct wf_fcu_fan *fan;
366 
367 	fan = kzalloc(sizeof(*fan), GFP_KERNEL);
368 	if (!fan)
369 		return;
370 	fan->fcu_priv = pv;
371 	fan->id = id;
372 	fan->ctrl.name = name;
373 	fan->ctrl.priv = fan;
374 
375 	/* min/max is oddball but the code comes from
376 	 * therm_pm72 which seems to work so ...
377 	 */
378 	if (type == FCU_FAN_RPM) {
379 		if (!strncmp(name, "cpu-pump", strlen("cpu-pump")))
380 			wf_fcu_get_pump_minmax(fan);
381 		else
382 			wf_fcu_get_rpmfan_minmax(fan);
383 		fan->ctrl.type = WF_CONTROL_RPM_FAN;
384 		fan->ctrl.ops = &wf_fcu_fan_rpm_ops;
385 	} else {
386 		fan->min = 10;
387 		fan->max = 100;
388 		fan->ctrl.type = WF_CONTROL_PWM_FAN;
389 		fan->ctrl.ops = &wf_fcu_fan_pwm_ops;
390 	}
391 
392 	if (wf_register_control(&fan->ctrl)) {
393 		pr_err("wf_fcu: Failed to register fan %s\n", name);
394 		kfree(fan);
395 		return;
396 	}
397 	list_add(&fan->link, &pv->fan_list);
398 	kref_get(&pv->ref);
399 }
400 
401 static void wf_fcu_lookup_fans(struct wf_fcu_priv *pv)
402 {
403 	/* Translation of device-tree location properties to
404 	 * windfarm fan names
405 	 */
406 	static const struct {
407 		const char *dt_name;	/* Device-tree name */
408 		const char *ct_name;	/* Control name */
409 	} loc_trans[] = {
410 		{ "BACKSIDE",		"backside-fan",		},
411 		{ "SYS CTRLR FAN",	"backside-fan",		},
412 		{ "DRIVE BAY",		"drive-bay-fan",	},
413 		{ "SLOT",		"slots-fan",		},
414 		{ "PCI FAN",		"slots-fan",		},
415 		{ "CPU A INTAKE",	"cpu-front-fan-0",	},
416 		{ "CPU A EXHAUST",	"cpu-rear-fan-0",	},
417 		{ "CPU B INTAKE",	"cpu-front-fan-1",	},
418 		{ "CPU B EXHAUST",	"cpu-rear-fan-1",	},
419 		{ "CPU A PUMP",		"cpu-pump-0",		},
420 		{ "CPU B PUMP",		"cpu-pump-1",		},
421 		{ "CPU A 1",		"cpu-fan-a-0",		},
422 		{ "CPU A 2",		"cpu-fan-b-0",		},
423 		{ "CPU A 3",		"cpu-fan-c-0",		},
424 		{ "CPU B 1",		"cpu-fan-a-1",		},
425 		{ "CPU B 2",		"cpu-fan-b-1",		},
426 		{ "CPU B 3",		"cpu-fan-c-1",		},
427 	};
428 	struct device_node *np = NULL, *fcu = pv->i2c->dev.of_node;
429 	int i;
430 
431 	DBG("Looking up FCU controls in device-tree...\n");
432 
433 	while ((np = of_get_next_child(fcu, np)) != NULL) {
434 		int id, type = -1;
435 		const char *loc;
436 		const char *name;
437 		const u32 *reg;
438 
439 		DBG(" control: %s, type: %s\n", np->name, np->type);
440 
441 		/* Detect control type */
442 		if (!strcmp(np->type, "fan-rpm-control") ||
443 		    !strcmp(np->type, "fan-rpm"))
444 			type = FCU_FAN_RPM;
445 		if (!strcmp(np->type, "fan-pwm-control") ||
446 		    !strcmp(np->type, "fan-pwm"))
447 			type = FCU_FAN_PWM;
448 		/* Only care about fans for now */
449 		if (type == -1)
450 			continue;
451 
452 		/* Lookup for a matching location */
453 		loc = of_get_property(np, "location", NULL);
454 		reg = of_get_property(np, "reg", NULL);
455 		if (loc == NULL || reg == NULL)
456 			continue;
457 		DBG(" matching location: %s, reg: 0x%08x\n", loc, *reg);
458 
459 		for (i = 0; i < ARRAY_SIZE(loc_trans); i++) {
460 			if (strncmp(loc, loc_trans[i].dt_name,
461 				    strlen(loc_trans[i].dt_name)))
462 				continue;
463 			name = loc_trans[i].ct_name;
464 
465 			DBG(" location match, name: %s\n", name);
466 
467 			if (type == FCU_FAN_RPM)
468 				id = ((*reg) - 0x10) / 2;
469 			else
470 				id = ((*reg) - 0x30) / 2;
471 			if (id > 7) {
472 				pr_warning("wf_fcu: Can't parse "
473 				       "fan ID in device-tree for %pOF\n",
474 					   np);
475 				break;
476 			}
477 			wf_fcu_add_fan(pv, name, type, id);
478 			break;
479 		}
480 	}
481 }
482 
483 static void wf_fcu_default_fans(struct wf_fcu_priv *pv)
484 {
485 	/* We only support the default fans for PowerMac7,2 */
486 	if (!of_machine_is_compatible("PowerMac7,2"))
487 		return;
488 
489 	wf_fcu_add_fan(pv, "backside-fan",	FCU_FAN_PWM, 1);
490 	wf_fcu_add_fan(pv, "drive-bay-fan",	FCU_FAN_RPM, 2);
491 	wf_fcu_add_fan(pv, "slots-fan",		FCU_FAN_PWM, 2);
492 	wf_fcu_add_fan(pv, "cpu-front-fan-0",	FCU_FAN_RPM, 3);
493 	wf_fcu_add_fan(pv, "cpu-rear-fan-0",	FCU_FAN_RPM, 4);
494 	wf_fcu_add_fan(pv, "cpu-front-fan-1",	FCU_FAN_RPM, 5);
495 	wf_fcu_add_fan(pv, "cpu-rear-fan-1",	FCU_FAN_RPM, 6);
496 }
497 
498 static int wf_fcu_init_chip(struct wf_fcu_priv *pv)
499 {
500 	unsigned char buf = 0xff;
501 	int rc;
502 
503 	rc = wf_fcu_write_reg(pv, 0xe, &buf, 1);
504 	if (rc < 0)
505 		return -EIO;
506 	rc = wf_fcu_write_reg(pv, 0x2e, &buf, 1);
507 	if (rc < 0)
508 		return -EIO;
509 	rc = wf_fcu_read_reg(pv, 0, &buf, 1);
510 	if (rc < 0)
511 		return -EIO;
512 	pv->rpm_shift = (buf == 1) ? 2 : 3;
513 
514 	pr_debug("wf_fcu: FCU Initialized, RPM fan shift is %d\n",
515 		 pv->rpm_shift);
516 
517 	return 0;
518 }
519 
520 static int wf_fcu_probe(struct i2c_client *client,
521 			const struct i2c_device_id *id)
522 {
523 	struct wf_fcu_priv *pv;
524 
525 	pv = kzalloc(sizeof(*pv), GFP_KERNEL);
526 	if (!pv)
527 		return -ENOMEM;
528 
529 	kref_init(&pv->ref);
530 	mutex_init(&pv->lock);
531 	INIT_LIST_HEAD(&pv->fan_list);
532 	pv->i2c = client;
533 
534 	/*
535 	 * First we must start the FCU which will query the
536 	 * shift value to apply to RPMs
537 	 */
538 	if (wf_fcu_init_chip(pv)) {
539 		pr_err("wf_fcu: Initialization failed !\n");
540 		kfree(pv);
541 		return -ENXIO;
542 	}
543 
544 	/* First lookup fans in the device-tree */
545 	wf_fcu_lookup_fans(pv);
546 
547 	/*
548 	 * Older machines don't have the device-tree entries
549 	 * we are looking for, just hard code the list
550 	 */
551 	if (list_empty(&pv->fan_list))
552 		wf_fcu_default_fans(pv);
553 
554 	/* Still no fans ? FAIL */
555 	if (list_empty(&pv->fan_list)) {
556 		pr_err("wf_fcu: Failed to find fans for your machine\n");
557 		kfree(pv);
558 		return -ENODEV;
559 	}
560 
561 	dev_set_drvdata(&client->dev, pv);
562 
563 	return 0;
564 }
565 
566 static int wf_fcu_remove(struct i2c_client *client)
567 {
568 	struct wf_fcu_priv *pv = dev_get_drvdata(&client->dev);
569 	struct wf_fcu_fan *fan;
570 
571 	while (!list_empty(&pv->fan_list)) {
572 		fan = list_first_entry(&pv->fan_list, struct wf_fcu_fan, link);
573 		list_del(&fan->link);
574 		wf_unregister_control(&fan->ctrl);
575 	}
576 	kref_put(&pv->ref, wf_fcu_release);
577 	return 0;
578 }
579 
580 static const struct i2c_device_id wf_fcu_id[] = {
581 	{ "MAC,fcu", 0 },
582 	{ }
583 };
584 MODULE_DEVICE_TABLE(i2c, wf_fcu_id);
585 
586 static struct i2c_driver wf_fcu_driver = {
587 	.driver = {
588 		.name	= "wf_fcu",
589 	},
590 	.probe		= wf_fcu_probe,
591 	.remove		= wf_fcu_remove,
592 	.id_table	= wf_fcu_id,
593 };
594 
595 module_i2c_driver(wf_fcu_driver);
596 
597 MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
598 MODULE_DESCRIPTION("FCU control objects for PowerMacs thermal control");
599 MODULE_LICENSE("GPL");
600 
601