1 /*
2  * dell-smm-hwmon.c -- Linux driver for accessing the SMM BIOS on Dell laptops.
3  *
4  * Copyright (C) 2001  Massimo Dal Zotto <dz@debian.org>
5  *
6  * Hwmon integration:
7  * Copyright (C) 2011  Jean Delvare <jdelvare@suse.de>
8  * Copyright (C) 2013, 2014  Guenter Roeck <linux@roeck-us.net>
9  * Copyright (C) 2014, 2015  Pali Rohár <pali.rohar@gmail.com>
10  *
11  * This program is free software; you can redistribute it and/or modify it
12  * under the terms of the GNU General Public License as published by the
13  * Free Software Foundation; either version 2, or (at your option) any
14  * later version.
15  *
16  * This program is distributed in the hope that it will be useful, but
17  * WITHOUT ANY WARRANTY; without even the implied warranty of
18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
19  * General Public License for more details.
20  */
21 
22 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
23 
24 #include <linux/delay.h>
25 #include <linux/module.h>
26 #include <linux/types.h>
27 #include <linux/init.h>
28 #include <linux/proc_fs.h>
29 #include <linux/seq_file.h>
30 #include <linux/dmi.h>
31 #include <linux/capability.h>
32 #include <linux/mutex.h>
33 #include <linux/hwmon.h>
34 #include <linux/hwmon-sysfs.h>
35 #include <linux/uaccess.h>
36 #include <linux/io.h>
37 #include <linux/sched.h>
38 #include <linux/ctype.h>
39 
40 #include <linux/i8k.h>
41 
42 #define I8K_SMM_FN_STATUS	0x0025
43 #define I8K_SMM_POWER_STATUS	0x0069
44 #define I8K_SMM_SET_FAN		0x01a3
45 #define I8K_SMM_GET_FAN		0x00a3
46 #define I8K_SMM_GET_SPEED	0x02a3
47 #define I8K_SMM_GET_FAN_TYPE	0x03a3
48 #define I8K_SMM_GET_NOM_SPEED	0x04a3
49 #define I8K_SMM_GET_TEMP	0x10a3
50 #define I8K_SMM_GET_TEMP_TYPE	0x11a3
51 #define I8K_SMM_GET_DELL_SIG1	0xfea3
52 #define I8K_SMM_GET_DELL_SIG2	0xffa3
53 
54 #define I8K_FAN_MULT		30
55 #define I8K_FAN_MAX_RPM		30000
56 #define I8K_MAX_TEMP		127
57 
58 #define I8K_FN_NONE		0x00
59 #define I8K_FN_UP		0x01
60 #define I8K_FN_DOWN		0x02
61 #define I8K_FN_MUTE		0x04
62 #define I8K_FN_MASK		0x07
63 #define I8K_FN_SHIFT		8
64 
65 #define I8K_POWER_AC		0x05
66 #define I8K_POWER_BATTERY	0x01
67 
68 static DEFINE_MUTEX(i8k_mutex);
69 static char bios_version[4];
70 static char bios_machineid[16];
71 static struct device *i8k_hwmon_dev;
72 static u32 i8k_hwmon_flags;
73 static uint i8k_fan_mult = I8K_FAN_MULT;
74 static uint i8k_pwm_mult;
75 static uint i8k_fan_max = I8K_FAN_HIGH;
76 static bool disallow_fan_type_call;
77 
78 #define I8K_HWMON_HAVE_TEMP1	(1 << 0)
79 #define I8K_HWMON_HAVE_TEMP2	(1 << 1)
80 #define I8K_HWMON_HAVE_TEMP3	(1 << 2)
81 #define I8K_HWMON_HAVE_TEMP4	(1 << 3)
82 #define I8K_HWMON_HAVE_FAN1	(1 << 4)
83 #define I8K_HWMON_HAVE_FAN2	(1 << 5)
84 
85 MODULE_AUTHOR("Massimo Dal Zotto (dz@debian.org)");
86 MODULE_AUTHOR("Pali Rohár <pali.rohar@gmail.com>");
87 MODULE_DESCRIPTION("Dell laptop SMM BIOS hwmon driver");
88 MODULE_LICENSE("GPL");
89 MODULE_ALIAS("i8k");
90 
91 static bool force;
92 module_param(force, bool, 0);
93 MODULE_PARM_DESC(force, "Force loading without checking for supported models");
94 
95 static bool ignore_dmi;
96 module_param(ignore_dmi, bool, 0);
97 MODULE_PARM_DESC(ignore_dmi, "Continue probing hardware even if DMI data does not match");
98 
99 #if IS_ENABLED(CONFIG_I8K)
100 static bool restricted = true;
101 module_param(restricted, bool, 0);
102 MODULE_PARM_DESC(restricted, "Restrict fan control and serial number to CAP_SYS_ADMIN (default: 1)");
103 
104 static bool power_status;
105 module_param(power_status, bool, 0600);
106 MODULE_PARM_DESC(power_status, "Report power status in /proc/i8k (default: 0)");
107 #endif
108 
109 static uint fan_mult;
110 module_param(fan_mult, uint, 0);
111 MODULE_PARM_DESC(fan_mult, "Factor to multiply fan speed with (default: autodetect)");
112 
113 static uint fan_max;
114 module_param(fan_max, uint, 0);
115 MODULE_PARM_DESC(fan_max, "Maximum configurable fan speed (default: autodetect)");
116 
117 struct smm_regs {
118 	unsigned int eax;
119 	unsigned int ebx __packed;
120 	unsigned int ecx __packed;
121 	unsigned int edx __packed;
122 	unsigned int esi __packed;
123 	unsigned int edi __packed;
124 };
125 
126 static inline const char *i8k_get_dmi_data(int field)
127 {
128 	const char *dmi_data = dmi_get_system_info(field);
129 
130 	return dmi_data && *dmi_data ? dmi_data : "?";
131 }
132 
133 /*
134  * Call the System Management Mode BIOS. Code provided by Jonathan Buzzard.
135  */
136 static int i8k_smm(struct smm_regs *regs)
137 {
138 	int rc;
139 	int eax = regs->eax;
140 	cpumask_var_t old_mask;
141 
142 	/* SMM requires CPU 0 */
143 	if (!alloc_cpumask_var(&old_mask, GFP_KERNEL))
144 		return -ENOMEM;
145 	cpumask_copy(old_mask, &current->cpus_allowed);
146 	rc = set_cpus_allowed_ptr(current, cpumask_of(0));
147 	if (rc)
148 		goto out;
149 	if (smp_processor_id() != 0) {
150 		rc = -EBUSY;
151 		goto out;
152 	}
153 
154 #if defined(CONFIG_X86_64)
155 	asm volatile("pushq %%rax\n\t"
156 		"movl 0(%%rax),%%edx\n\t"
157 		"pushq %%rdx\n\t"
158 		"movl 4(%%rax),%%ebx\n\t"
159 		"movl 8(%%rax),%%ecx\n\t"
160 		"movl 12(%%rax),%%edx\n\t"
161 		"movl 16(%%rax),%%esi\n\t"
162 		"movl 20(%%rax),%%edi\n\t"
163 		"popq %%rax\n\t"
164 		"out %%al,$0xb2\n\t"
165 		"out %%al,$0x84\n\t"
166 		"xchgq %%rax,(%%rsp)\n\t"
167 		"movl %%ebx,4(%%rax)\n\t"
168 		"movl %%ecx,8(%%rax)\n\t"
169 		"movl %%edx,12(%%rax)\n\t"
170 		"movl %%esi,16(%%rax)\n\t"
171 		"movl %%edi,20(%%rax)\n\t"
172 		"popq %%rdx\n\t"
173 		"movl %%edx,0(%%rax)\n\t"
174 		"pushfq\n\t"
175 		"popq %%rax\n\t"
176 		"andl $1,%%eax\n"
177 		: "=a"(rc)
178 		:    "a"(regs)
179 		:    "%ebx", "%ecx", "%edx", "%esi", "%edi", "memory");
180 #else
181 	asm volatile("pushl %%eax\n\t"
182 	    "movl 0(%%eax),%%edx\n\t"
183 	    "push %%edx\n\t"
184 	    "movl 4(%%eax),%%ebx\n\t"
185 	    "movl 8(%%eax),%%ecx\n\t"
186 	    "movl 12(%%eax),%%edx\n\t"
187 	    "movl 16(%%eax),%%esi\n\t"
188 	    "movl 20(%%eax),%%edi\n\t"
189 	    "popl %%eax\n\t"
190 	    "out %%al,$0xb2\n\t"
191 	    "out %%al,$0x84\n\t"
192 	    "xchgl %%eax,(%%esp)\n\t"
193 	    "movl %%ebx,4(%%eax)\n\t"
194 	    "movl %%ecx,8(%%eax)\n\t"
195 	    "movl %%edx,12(%%eax)\n\t"
196 	    "movl %%esi,16(%%eax)\n\t"
197 	    "movl %%edi,20(%%eax)\n\t"
198 	    "popl %%edx\n\t"
199 	    "movl %%edx,0(%%eax)\n\t"
200 	    "lahf\n\t"
201 	    "shrl $8,%%eax\n\t"
202 	    "andl $1,%%eax\n"
203 	    : "=a"(rc)
204 	    :    "a"(regs)
205 	    :    "%ebx", "%ecx", "%edx", "%esi", "%edi", "memory");
206 #endif
207 	if (rc != 0 || (regs->eax & 0xffff) == 0xffff || regs->eax == eax)
208 		rc = -EINVAL;
209 
210 out:
211 	set_cpus_allowed_ptr(current, old_mask);
212 	free_cpumask_var(old_mask);
213 	return rc;
214 }
215 
216 /*
217  * Read the fan status.
218  */
219 static int i8k_get_fan_status(int fan)
220 {
221 	struct smm_regs regs = { .eax = I8K_SMM_GET_FAN, };
222 
223 	regs.ebx = fan & 0xff;
224 	return i8k_smm(&regs) ? : regs.eax & 0xff;
225 }
226 
227 /*
228  * Read the fan speed in RPM.
229  */
230 static int i8k_get_fan_speed(int fan)
231 {
232 	struct smm_regs regs = { .eax = I8K_SMM_GET_SPEED, };
233 
234 	regs.ebx = fan & 0xff;
235 	return i8k_smm(&regs) ? : (regs.eax & 0xffff) * i8k_fan_mult;
236 }
237 
238 /*
239  * Read the fan type.
240  */
241 static int _i8k_get_fan_type(int fan)
242 {
243 	struct smm_regs regs = { .eax = I8K_SMM_GET_FAN_TYPE, };
244 
245 	if (disallow_fan_type_call)
246 		return -EINVAL;
247 
248 	regs.ebx = fan & 0xff;
249 	return i8k_smm(&regs) ? : regs.eax & 0xff;
250 }
251 
252 static int i8k_get_fan_type(int fan)
253 {
254 	/* I8K_SMM_GET_FAN_TYPE SMM call is expensive, so cache values */
255 	static int types[2] = { INT_MIN, INT_MIN };
256 
257 	if (types[fan] == INT_MIN)
258 		types[fan] = _i8k_get_fan_type(fan);
259 
260 	return types[fan];
261 }
262 
263 /*
264  * Read the fan nominal rpm for specific fan speed.
265  */
266 static int i8k_get_fan_nominal_speed(int fan, int speed)
267 {
268 	struct smm_regs regs = { .eax = I8K_SMM_GET_NOM_SPEED, };
269 
270 	regs.ebx = (fan & 0xff) | (speed << 8);
271 	return i8k_smm(&regs) ? : (regs.eax & 0xffff) * i8k_fan_mult;
272 }
273 
274 /*
275  * Set the fan speed (off, low, high). Returns the new fan status.
276  */
277 static int i8k_set_fan(int fan, int speed)
278 {
279 	struct smm_regs regs = { .eax = I8K_SMM_SET_FAN, };
280 
281 	speed = (speed < 0) ? 0 : ((speed > i8k_fan_max) ? i8k_fan_max : speed);
282 	regs.ebx = (fan & 0xff) | (speed << 8);
283 
284 	return i8k_smm(&regs) ? : i8k_get_fan_status(fan);
285 }
286 
287 static int i8k_get_temp_type(int sensor)
288 {
289 	struct smm_regs regs = { .eax = I8K_SMM_GET_TEMP_TYPE, };
290 
291 	regs.ebx = sensor & 0xff;
292 	return i8k_smm(&regs) ? : regs.eax & 0xff;
293 }
294 
295 /*
296  * Read the cpu temperature.
297  */
298 static int _i8k_get_temp(int sensor)
299 {
300 	struct smm_regs regs = {
301 		.eax = I8K_SMM_GET_TEMP,
302 		.ebx = sensor & 0xff,
303 	};
304 
305 	return i8k_smm(&regs) ? : regs.eax & 0xff;
306 }
307 
308 static int i8k_get_temp(int sensor)
309 {
310 	int temp = _i8k_get_temp(sensor);
311 
312 	/*
313 	 * Sometimes the temperature sensor returns 0x99, which is out of range.
314 	 * In this case we retry (once) before returning an error.
315 	 # 1003655137 00000058 00005a4b
316 	 # 1003655138 00000099 00003a80 <--- 0x99 = 153 degrees
317 	 # 1003655139 00000054 00005c52
318 	 */
319 	if (temp == 0x99) {
320 		msleep(100);
321 		temp = _i8k_get_temp(sensor);
322 	}
323 	/*
324 	 * Return -ENODATA for all invalid temperatures.
325 	 *
326 	 * Known instances are the 0x99 value as seen above as well as
327 	 * 0xc1 (193), which may be returned when trying to read the GPU
328 	 * temperature if the system supports a GPU and it is currently
329 	 * turned off.
330 	 */
331 	if (temp > I8K_MAX_TEMP)
332 		return -ENODATA;
333 
334 	return temp;
335 }
336 
337 static int i8k_get_dell_signature(int req_fn)
338 {
339 	struct smm_regs regs = { .eax = req_fn, };
340 	int rc;
341 
342 	rc = i8k_smm(&regs);
343 	if (rc < 0)
344 		return rc;
345 
346 	return regs.eax == 1145651527 && regs.edx == 1145392204 ? 0 : -1;
347 }
348 
349 #if IS_ENABLED(CONFIG_I8K)
350 
351 /*
352  * Read the Fn key status.
353  */
354 static int i8k_get_fn_status(void)
355 {
356 	struct smm_regs regs = { .eax = I8K_SMM_FN_STATUS, };
357 	int rc;
358 
359 	rc = i8k_smm(&regs);
360 	if (rc < 0)
361 		return rc;
362 
363 	switch ((regs.eax >> I8K_FN_SHIFT) & I8K_FN_MASK) {
364 	case I8K_FN_UP:
365 		return I8K_VOL_UP;
366 	case I8K_FN_DOWN:
367 		return I8K_VOL_DOWN;
368 	case I8K_FN_MUTE:
369 		return I8K_VOL_MUTE;
370 	default:
371 		return 0;
372 	}
373 }
374 
375 /*
376  * Read the power status.
377  */
378 static int i8k_get_power_status(void)
379 {
380 	struct smm_regs regs = { .eax = I8K_SMM_POWER_STATUS, };
381 	int rc;
382 
383 	rc = i8k_smm(&regs);
384 	if (rc < 0)
385 		return rc;
386 
387 	return (regs.eax & 0xff) == I8K_POWER_AC ? I8K_AC : I8K_BATTERY;
388 }
389 
390 /*
391  * Procfs interface
392  */
393 
394 static int
395 i8k_ioctl_unlocked(struct file *fp, unsigned int cmd, unsigned long arg)
396 {
397 	int val = 0;
398 	int speed;
399 	unsigned char buff[16];
400 	int __user *argp = (int __user *)arg;
401 
402 	if (!argp)
403 		return -EINVAL;
404 
405 	switch (cmd) {
406 	case I8K_BIOS_VERSION:
407 		if (!isdigit(bios_version[0]) || !isdigit(bios_version[1]) ||
408 		    !isdigit(bios_version[2]))
409 			return -EINVAL;
410 
411 		val = (bios_version[0] << 16) |
412 				(bios_version[1] << 8) | bios_version[2];
413 		break;
414 
415 	case I8K_MACHINE_ID:
416 		if (restricted && !capable(CAP_SYS_ADMIN))
417 			return -EPERM;
418 
419 		memset(buff, 0, sizeof(buff));
420 		strlcpy(buff, bios_machineid, sizeof(buff));
421 		break;
422 
423 	case I8K_FN_STATUS:
424 		val = i8k_get_fn_status();
425 		break;
426 
427 	case I8K_POWER_STATUS:
428 		val = i8k_get_power_status();
429 		break;
430 
431 	case I8K_GET_TEMP:
432 		val = i8k_get_temp(0);
433 		break;
434 
435 	case I8K_GET_SPEED:
436 		if (copy_from_user(&val, argp, sizeof(int)))
437 			return -EFAULT;
438 
439 		val = i8k_get_fan_speed(val);
440 		break;
441 
442 	case I8K_GET_FAN:
443 		if (copy_from_user(&val, argp, sizeof(int)))
444 			return -EFAULT;
445 
446 		val = i8k_get_fan_status(val);
447 		break;
448 
449 	case I8K_SET_FAN:
450 		if (restricted && !capable(CAP_SYS_ADMIN))
451 			return -EPERM;
452 
453 		if (copy_from_user(&val, argp, sizeof(int)))
454 			return -EFAULT;
455 
456 		if (copy_from_user(&speed, argp + 1, sizeof(int)))
457 			return -EFAULT;
458 
459 		val = i8k_set_fan(val, speed);
460 		break;
461 
462 	default:
463 		return -EINVAL;
464 	}
465 
466 	if (val < 0)
467 		return val;
468 
469 	switch (cmd) {
470 	case I8K_BIOS_VERSION:
471 		if (copy_to_user(argp, &val, 4))
472 			return -EFAULT;
473 
474 		break;
475 	case I8K_MACHINE_ID:
476 		if (copy_to_user(argp, buff, 16))
477 			return -EFAULT;
478 
479 		break;
480 	default:
481 		if (copy_to_user(argp, &val, sizeof(int)))
482 			return -EFAULT;
483 
484 		break;
485 	}
486 
487 	return 0;
488 }
489 
490 static long i8k_ioctl(struct file *fp, unsigned int cmd, unsigned long arg)
491 {
492 	long ret;
493 
494 	mutex_lock(&i8k_mutex);
495 	ret = i8k_ioctl_unlocked(fp, cmd, arg);
496 	mutex_unlock(&i8k_mutex);
497 
498 	return ret;
499 }
500 
501 /*
502  * Print the information for /proc/i8k.
503  */
504 static int i8k_proc_show(struct seq_file *seq, void *offset)
505 {
506 	int fn_key, cpu_temp, ac_power;
507 	int left_fan, right_fan, left_speed, right_speed;
508 
509 	cpu_temp	= i8k_get_temp(0);			/* 11100 µs */
510 	left_fan	= i8k_get_fan_status(I8K_FAN_LEFT);	/*   580 µs */
511 	right_fan	= i8k_get_fan_status(I8K_FAN_RIGHT);	/*   580 µs */
512 	left_speed	= i8k_get_fan_speed(I8K_FAN_LEFT);	/*   580 µs */
513 	right_speed	= i8k_get_fan_speed(I8K_FAN_RIGHT);	/*   580 µs */
514 	fn_key		= i8k_get_fn_status();			/*   750 µs */
515 	if (power_status)
516 		ac_power = i8k_get_power_status();		/* 14700 µs */
517 	else
518 		ac_power = -1;
519 
520 	/*
521 	 * Info:
522 	 *
523 	 * 1)  Format version (this will change if format changes)
524 	 * 2)  BIOS version
525 	 * 3)  BIOS machine ID
526 	 * 4)  Cpu temperature
527 	 * 5)  Left fan status
528 	 * 6)  Right fan status
529 	 * 7)  Left fan speed
530 	 * 8)  Right fan speed
531 	 * 9)  AC power
532 	 * 10) Fn Key status
533 	 */
534 	seq_printf(seq, "%s %s %s %d %d %d %d %d %d %d\n",
535 		   I8K_PROC_FMT,
536 		   bios_version,
537 		   (restricted && !capable(CAP_SYS_ADMIN)) ? "-1" : bios_machineid,
538 		   cpu_temp,
539 		   left_fan, right_fan, left_speed, right_speed,
540 		   ac_power, fn_key);
541 
542 	return 0;
543 }
544 
545 static int i8k_open_fs(struct inode *inode, struct file *file)
546 {
547 	return single_open(file, i8k_proc_show, NULL);
548 }
549 
550 static const struct file_operations i8k_fops = {
551 	.owner		= THIS_MODULE,
552 	.open		= i8k_open_fs,
553 	.read		= seq_read,
554 	.llseek		= seq_lseek,
555 	.release	= single_release,
556 	.unlocked_ioctl	= i8k_ioctl,
557 };
558 
559 static void __init i8k_init_procfs(void)
560 {
561 	/* Register the proc entry */
562 	proc_create("i8k", 0, NULL, &i8k_fops);
563 }
564 
565 static void __exit i8k_exit_procfs(void)
566 {
567 	remove_proc_entry("i8k", NULL);
568 }
569 
570 #else
571 
572 static inline void __init i8k_init_procfs(void)
573 {
574 }
575 
576 static inline void __exit i8k_exit_procfs(void)
577 {
578 }
579 
580 #endif
581 
582 /*
583  * Hwmon interface
584  */
585 
586 static ssize_t i8k_hwmon_show_temp_label(struct device *dev,
587 					 struct device_attribute *devattr,
588 					 char *buf)
589 {
590 	static const char * const labels[] = {
591 		"CPU",
592 		"GPU",
593 		"SODIMM",
594 		"Other",
595 		"Ambient",
596 		"Other",
597 	};
598 	int index = to_sensor_dev_attr(devattr)->index;
599 	int type;
600 
601 	type = i8k_get_temp_type(index);
602 	if (type < 0)
603 		return type;
604 	if (type >= ARRAY_SIZE(labels))
605 		type = ARRAY_SIZE(labels) - 1;
606 	return sprintf(buf, "%s\n", labels[type]);
607 }
608 
609 static ssize_t i8k_hwmon_show_temp(struct device *dev,
610 				   struct device_attribute *devattr,
611 				   char *buf)
612 {
613 	int index = to_sensor_dev_attr(devattr)->index;
614 	int temp;
615 
616 	temp = i8k_get_temp(index);
617 	if (temp < 0)
618 		return temp;
619 	return sprintf(buf, "%d\n", temp * 1000);
620 }
621 
622 static ssize_t i8k_hwmon_show_fan_label(struct device *dev,
623 					struct device_attribute *devattr,
624 					char *buf)
625 {
626 	static const char * const labels[] = {
627 		"Processor Fan",
628 		"Motherboard Fan",
629 		"Video Fan",
630 		"Power Supply Fan",
631 		"Chipset Fan",
632 		"Other Fan",
633 	};
634 	int index = to_sensor_dev_attr(devattr)->index;
635 	bool dock = false;
636 	int type;
637 
638 	type = i8k_get_fan_type(index);
639 	if (type < 0)
640 		return type;
641 
642 	if (type & 0x10) {
643 		dock = true;
644 		type &= 0x0F;
645 	}
646 
647 	if (type >= ARRAY_SIZE(labels))
648 		type = (ARRAY_SIZE(labels) - 1);
649 
650 	return sprintf(buf, "%s%s\n", (dock ? "Docking " : ""), labels[type]);
651 }
652 
653 static ssize_t i8k_hwmon_show_fan(struct device *dev,
654 				  struct device_attribute *devattr,
655 				  char *buf)
656 {
657 	int index = to_sensor_dev_attr(devattr)->index;
658 	int fan_speed;
659 
660 	fan_speed = i8k_get_fan_speed(index);
661 	if (fan_speed < 0)
662 		return fan_speed;
663 	return sprintf(buf, "%d\n", fan_speed);
664 }
665 
666 static ssize_t i8k_hwmon_show_pwm(struct device *dev,
667 				  struct device_attribute *devattr,
668 				  char *buf)
669 {
670 	int index = to_sensor_dev_attr(devattr)->index;
671 	int status;
672 
673 	status = i8k_get_fan_status(index);
674 	if (status < 0)
675 		return -EIO;
676 	return sprintf(buf, "%d\n", clamp_val(status * i8k_pwm_mult, 0, 255));
677 }
678 
679 static ssize_t i8k_hwmon_set_pwm(struct device *dev,
680 				 struct device_attribute *attr,
681 				 const char *buf, size_t count)
682 {
683 	int index = to_sensor_dev_attr(attr)->index;
684 	unsigned long val;
685 	int err;
686 
687 	err = kstrtoul(buf, 10, &val);
688 	if (err)
689 		return err;
690 	val = clamp_val(DIV_ROUND_CLOSEST(val, i8k_pwm_mult), 0, i8k_fan_max);
691 
692 	mutex_lock(&i8k_mutex);
693 	err = i8k_set_fan(index, val);
694 	mutex_unlock(&i8k_mutex);
695 
696 	return err < 0 ? -EIO : count;
697 }
698 
699 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, i8k_hwmon_show_temp, NULL, 0);
700 static SENSOR_DEVICE_ATTR(temp1_label, S_IRUGO, i8k_hwmon_show_temp_label, NULL,
701 			  0);
702 static SENSOR_DEVICE_ATTR(temp2_input, S_IRUGO, i8k_hwmon_show_temp, NULL, 1);
703 static SENSOR_DEVICE_ATTR(temp2_label, S_IRUGO, i8k_hwmon_show_temp_label, NULL,
704 			  1);
705 static SENSOR_DEVICE_ATTR(temp3_input, S_IRUGO, i8k_hwmon_show_temp, NULL, 2);
706 static SENSOR_DEVICE_ATTR(temp3_label, S_IRUGO, i8k_hwmon_show_temp_label, NULL,
707 			  2);
708 static SENSOR_DEVICE_ATTR(temp4_input, S_IRUGO, i8k_hwmon_show_temp, NULL, 3);
709 static SENSOR_DEVICE_ATTR(temp4_label, S_IRUGO, i8k_hwmon_show_temp_label, NULL,
710 			  3);
711 static SENSOR_DEVICE_ATTR(fan1_input, S_IRUGO, i8k_hwmon_show_fan, NULL, 0);
712 static SENSOR_DEVICE_ATTR(fan1_label, S_IRUGO, i8k_hwmon_show_fan_label, NULL,
713 			  0);
714 static SENSOR_DEVICE_ATTR(pwm1, S_IRUGO | S_IWUSR, i8k_hwmon_show_pwm,
715 			  i8k_hwmon_set_pwm, 0);
716 static SENSOR_DEVICE_ATTR(fan2_input, S_IRUGO, i8k_hwmon_show_fan, NULL,
717 			  1);
718 static SENSOR_DEVICE_ATTR(fan2_label, S_IRUGO, i8k_hwmon_show_fan_label, NULL,
719 			  1);
720 static SENSOR_DEVICE_ATTR(pwm2, S_IRUGO | S_IWUSR, i8k_hwmon_show_pwm,
721 			  i8k_hwmon_set_pwm, 1);
722 
723 static struct attribute *i8k_attrs[] = {
724 	&sensor_dev_attr_temp1_input.dev_attr.attr,	/* 0 */
725 	&sensor_dev_attr_temp1_label.dev_attr.attr,	/* 1 */
726 	&sensor_dev_attr_temp2_input.dev_attr.attr,	/* 2 */
727 	&sensor_dev_attr_temp2_label.dev_attr.attr,	/* 3 */
728 	&sensor_dev_attr_temp3_input.dev_attr.attr,	/* 4 */
729 	&sensor_dev_attr_temp3_label.dev_attr.attr,	/* 5 */
730 	&sensor_dev_attr_temp4_input.dev_attr.attr,	/* 6 */
731 	&sensor_dev_attr_temp4_label.dev_attr.attr,	/* 7 */
732 	&sensor_dev_attr_fan1_input.dev_attr.attr,	/* 8 */
733 	&sensor_dev_attr_fan1_label.dev_attr.attr,	/* 9 */
734 	&sensor_dev_attr_pwm1.dev_attr.attr,		/* 10 */
735 	&sensor_dev_attr_fan2_input.dev_attr.attr,	/* 11 */
736 	&sensor_dev_attr_fan2_label.dev_attr.attr,	/* 12 */
737 	&sensor_dev_attr_pwm2.dev_attr.attr,		/* 13 */
738 	NULL
739 };
740 
741 static umode_t i8k_is_visible(struct kobject *kobj, struct attribute *attr,
742 			      int index)
743 {
744 	if (disallow_fan_type_call &&
745 	    (index == 9 || index == 12))
746 		return 0;
747 	if (index >= 0 && index <= 1 &&
748 	    !(i8k_hwmon_flags & I8K_HWMON_HAVE_TEMP1))
749 		return 0;
750 	if (index >= 2 && index <= 3 &&
751 	    !(i8k_hwmon_flags & I8K_HWMON_HAVE_TEMP2))
752 		return 0;
753 	if (index >= 4 && index <= 5 &&
754 	    !(i8k_hwmon_flags & I8K_HWMON_HAVE_TEMP3))
755 		return 0;
756 	if (index >= 6 && index <= 7 &&
757 	    !(i8k_hwmon_flags & I8K_HWMON_HAVE_TEMP4))
758 		return 0;
759 	if (index >= 8 && index <= 10 &&
760 	    !(i8k_hwmon_flags & I8K_HWMON_HAVE_FAN1))
761 		return 0;
762 	if (index >= 11 && index <= 13 &&
763 	    !(i8k_hwmon_flags & I8K_HWMON_HAVE_FAN2))
764 		return 0;
765 
766 	return attr->mode;
767 }
768 
769 static const struct attribute_group i8k_group = {
770 	.attrs = i8k_attrs,
771 	.is_visible = i8k_is_visible,
772 };
773 __ATTRIBUTE_GROUPS(i8k);
774 
775 static int __init i8k_init_hwmon(void)
776 {
777 	int err;
778 
779 	i8k_hwmon_flags = 0;
780 
781 	/* CPU temperature attributes, if temperature type is OK */
782 	err = i8k_get_temp_type(0);
783 	if (err >= 0)
784 		i8k_hwmon_flags |= I8K_HWMON_HAVE_TEMP1;
785 	/* check for additional temperature sensors */
786 	err = i8k_get_temp_type(1);
787 	if (err >= 0)
788 		i8k_hwmon_flags |= I8K_HWMON_HAVE_TEMP2;
789 	err = i8k_get_temp_type(2);
790 	if (err >= 0)
791 		i8k_hwmon_flags |= I8K_HWMON_HAVE_TEMP3;
792 	err = i8k_get_temp_type(3);
793 	if (err >= 0)
794 		i8k_hwmon_flags |= I8K_HWMON_HAVE_TEMP4;
795 
796 	/* First fan attributes, if fan status or type is OK */
797 	err = i8k_get_fan_status(0);
798 	if (err < 0)
799 		err = i8k_get_fan_type(0);
800 	if (err >= 0)
801 		i8k_hwmon_flags |= I8K_HWMON_HAVE_FAN1;
802 
803 	/* Second fan attributes, if fan status or type is OK */
804 	err = i8k_get_fan_status(1);
805 	if (err < 0)
806 		err = i8k_get_fan_type(1);
807 	if (err >= 0)
808 		i8k_hwmon_flags |= I8K_HWMON_HAVE_FAN2;
809 
810 	i8k_hwmon_dev = hwmon_device_register_with_groups(NULL, "dell_smm",
811 							  NULL, i8k_groups);
812 	if (IS_ERR(i8k_hwmon_dev)) {
813 		err = PTR_ERR(i8k_hwmon_dev);
814 		i8k_hwmon_dev = NULL;
815 		pr_err("hwmon registration failed (%d)\n", err);
816 		return err;
817 	}
818 	return 0;
819 }
820 
821 struct i8k_config_data {
822 	uint fan_mult;
823 	uint fan_max;
824 };
825 
826 enum i8k_configs {
827 	DELL_LATITUDE_D520,
828 	DELL_PRECISION_490,
829 	DELL_STUDIO,
830 	DELL_XPS,
831 };
832 
833 static const struct i8k_config_data i8k_config_data[] = {
834 	[DELL_LATITUDE_D520] = {
835 		.fan_mult = 1,
836 		.fan_max = I8K_FAN_TURBO,
837 	},
838 	[DELL_PRECISION_490] = {
839 		.fan_mult = 1,
840 		.fan_max = I8K_FAN_TURBO,
841 	},
842 	[DELL_STUDIO] = {
843 		.fan_mult = 1,
844 		.fan_max = I8K_FAN_HIGH,
845 	},
846 	[DELL_XPS] = {
847 		.fan_mult = 1,
848 		.fan_max = I8K_FAN_HIGH,
849 	},
850 };
851 
852 static struct dmi_system_id i8k_dmi_table[] __initdata = {
853 	{
854 		.ident = "Dell Inspiron",
855 		.matches = {
856 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer"),
857 			DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron"),
858 		},
859 	},
860 	{
861 		.ident = "Dell Latitude",
862 		.matches = {
863 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer"),
864 			DMI_MATCH(DMI_PRODUCT_NAME, "Latitude"),
865 		},
866 	},
867 	{
868 		.ident = "Dell Inspiron 2",
869 		.matches = {
870 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
871 			DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron"),
872 		},
873 	},
874 	{
875 		.ident = "Dell Latitude D520",
876 		.matches = {
877 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
878 			DMI_MATCH(DMI_PRODUCT_NAME, "Latitude D520"),
879 		},
880 		.driver_data = (void *)&i8k_config_data[DELL_LATITUDE_D520],
881 	},
882 	{
883 		.ident = "Dell Latitude 2",
884 		.matches = {
885 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
886 			DMI_MATCH(DMI_PRODUCT_NAME, "Latitude"),
887 		},
888 	},
889 	{	/* UK Inspiron 6400  */
890 		.ident = "Dell Inspiron 3",
891 		.matches = {
892 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
893 			DMI_MATCH(DMI_PRODUCT_NAME, "MM061"),
894 		},
895 	},
896 	{
897 		.ident = "Dell Inspiron 3",
898 		.matches = {
899 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
900 			DMI_MATCH(DMI_PRODUCT_NAME, "MP061"),
901 		},
902 	},
903 	{
904 		.ident = "Dell Precision 490",
905 		.matches = {
906 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
907 			DMI_MATCH(DMI_PRODUCT_NAME,
908 				  "Precision WorkStation 490"),
909 		},
910 		.driver_data = (void *)&i8k_config_data[DELL_PRECISION_490],
911 	},
912 	{
913 		.ident = "Dell Precision",
914 		.matches = {
915 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
916 			DMI_MATCH(DMI_PRODUCT_NAME, "Precision"),
917 		},
918 	},
919 	{
920 		.ident = "Dell Vostro",
921 		.matches = {
922 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
923 			DMI_MATCH(DMI_PRODUCT_NAME, "Vostro"),
924 		},
925 	},
926 	{
927 		.ident = "Dell XPS421",
928 		.matches = {
929 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
930 			DMI_MATCH(DMI_PRODUCT_NAME, "XPS L421X"),
931 		},
932 	},
933 	{
934 		.ident = "Dell Studio",
935 		.matches = {
936 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
937 			DMI_MATCH(DMI_PRODUCT_NAME, "Studio"),
938 		},
939 		.driver_data = (void *)&i8k_config_data[DELL_STUDIO],
940 	},
941 	{
942 		.ident = "Dell XPS 13",
943 		.matches = {
944 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
945 			DMI_MATCH(DMI_PRODUCT_NAME, "XPS13"),
946 		},
947 		.driver_data = (void *)&i8k_config_data[DELL_XPS],
948 	},
949 	{
950 		.ident = "Dell XPS M140",
951 		.matches = {
952 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
953 			DMI_MATCH(DMI_PRODUCT_NAME, "MXC051"),
954 		},
955 		.driver_data = (void *)&i8k_config_data[DELL_XPS],
956 	},
957 	{ }
958 };
959 
960 MODULE_DEVICE_TABLE(dmi, i8k_dmi_table);
961 
962 /*
963  * On some machines once I8K_SMM_GET_FAN_TYPE is issued then CPU fan speed
964  * randomly going up and down due to bug in Dell SMM or BIOS. Here is blacklist
965  * of affected Dell machines for which we disallow I8K_SMM_GET_FAN_TYPE call.
966  * See bug: https://bugzilla.kernel.org/show_bug.cgi?id=100121
967  */
968 static struct dmi_system_id i8k_blacklist_fan_type_dmi_table[] __initdata = {
969 	{
970 		.ident = "Dell Studio XPS 8000",
971 		.matches = {
972 			DMI_EXACT_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
973 			DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Studio XPS 8000"),
974 		},
975 	},
976 	{
977 		.ident = "Dell Studio XPS 8100",
978 		.matches = {
979 			DMI_EXACT_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
980 			DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Studio XPS 8100"),
981 		},
982 	},
983 	{
984 		.ident = "Dell Inspiron 580",
985 		.matches = {
986 			DMI_EXACT_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
987 			DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Inspiron 580 "),
988 		},
989 	},
990 	{ }
991 };
992 
993 /*
994  * Probe for the presence of a supported laptop.
995  */
996 static int __init i8k_probe(void)
997 {
998 	const struct dmi_system_id *id;
999 	int fan, ret;
1000 
1001 	/*
1002 	 * Get DMI information
1003 	 */
1004 	if (!dmi_check_system(i8k_dmi_table)) {
1005 		if (!ignore_dmi && !force)
1006 			return -ENODEV;
1007 
1008 		pr_info("not running on a supported Dell system.\n");
1009 		pr_info("vendor=%s, model=%s, version=%s\n",
1010 			i8k_get_dmi_data(DMI_SYS_VENDOR),
1011 			i8k_get_dmi_data(DMI_PRODUCT_NAME),
1012 			i8k_get_dmi_data(DMI_BIOS_VERSION));
1013 	}
1014 
1015 	if (dmi_check_system(i8k_blacklist_fan_type_dmi_table))
1016 		disallow_fan_type_call = true;
1017 
1018 	strlcpy(bios_version, i8k_get_dmi_data(DMI_BIOS_VERSION),
1019 		sizeof(bios_version));
1020 	strlcpy(bios_machineid, i8k_get_dmi_data(DMI_PRODUCT_SERIAL),
1021 		sizeof(bios_machineid));
1022 
1023 	/*
1024 	 * Get SMM Dell signature
1025 	 */
1026 	if (i8k_get_dell_signature(I8K_SMM_GET_DELL_SIG1) &&
1027 	    i8k_get_dell_signature(I8K_SMM_GET_DELL_SIG2)) {
1028 		pr_err("unable to get SMM Dell signature\n");
1029 		if (!force)
1030 			return -ENODEV;
1031 	}
1032 
1033 	/*
1034 	 * Set fan multiplier and maximal fan speed from dmi config
1035 	 * Values specified in module parameters override values from dmi
1036 	 */
1037 	id = dmi_first_match(i8k_dmi_table);
1038 	if (id && id->driver_data) {
1039 		const struct i8k_config_data *conf = id->driver_data;
1040 		if (!fan_mult && conf->fan_mult)
1041 			fan_mult = conf->fan_mult;
1042 		if (!fan_max && conf->fan_max)
1043 			fan_max = conf->fan_max;
1044 	}
1045 
1046 	i8k_fan_max = fan_max ? : I8K_FAN_HIGH;	/* Must not be 0 */
1047 	i8k_pwm_mult = DIV_ROUND_UP(255, i8k_fan_max);
1048 
1049 	if (!fan_mult) {
1050 		/*
1051 		 * Autodetect fan multiplier based on nominal rpm
1052 		 * If fan reports rpm value too high then set multiplier to 1
1053 		 */
1054 		for (fan = 0; fan < 2; ++fan) {
1055 			ret = i8k_get_fan_nominal_speed(fan, i8k_fan_max);
1056 			if (ret < 0)
1057 				continue;
1058 			if (ret > I8K_FAN_MAX_RPM)
1059 				i8k_fan_mult = 1;
1060 			break;
1061 		}
1062 	} else {
1063 		/* Fan multiplier was specified in module param or in dmi */
1064 		i8k_fan_mult = fan_mult;
1065 	}
1066 
1067 	return 0;
1068 }
1069 
1070 static int __init i8k_init(void)
1071 {
1072 	int err;
1073 
1074 	/* Are we running on an supported laptop? */
1075 	if (i8k_probe())
1076 		return -ENODEV;
1077 
1078 	err = i8k_init_hwmon();
1079 	if (err)
1080 		return err;
1081 
1082 	i8k_init_procfs();
1083 	return 0;
1084 }
1085 
1086 static void __exit i8k_exit(void)
1087 {
1088 	hwmon_device_unregister(i8k_hwmon_dev);
1089 	i8k_exit_procfs();
1090 }
1091 
1092 module_init(i8k_init);
1093 module_exit(i8k_exit);
1094