1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * dell-smm-hwmon.c -- Linux driver for accessing the SMM BIOS on Dell laptops.
4  *
5  * Copyright (C) 2001  Massimo Dal Zotto <dz@debian.org>
6  *
7  * Hwmon integration:
8  * Copyright (C) 2011  Jean Delvare <jdelvare@suse.de>
9  * Copyright (C) 2013, 2014  Guenter Roeck <linux@roeck-us.net>
10  * Copyright (C) 2014, 2015  Pali Rohár <pali@kernel.org>
11  */
12 
13 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
14 
15 #include <linux/cpu.h>
16 #include <linux/delay.h>
17 #include <linux/err.h>
18 #include <linux/module.h>
19 #include <linux/platform_device.h>
20 #include <linux/types.h>
21 #include <linux/init.h>
22 #include <linux/proc_fs.h>
23 #include <linux/seq_file.h>
24 #include <linux/dmi.h>
25 #include <linux/capability.h>
26 #include <linux/mutex.h>
27 #include <linux/hwmon.h>
28 #include <linux/uaccess.h>
29 #include <linux/io.h>
30 #include <linux/sched.h>
31 #include <linux/ctype.h>
32 #include <linux/smp.h>
33 
34 #include <linux/i8k.h>
35 
36 #define I8K_SMM_FN_STATUS	0x0025
37 #define I8K_SMM_POWER_STATUS	0x0069
38 #define I8K_SMM_SET_FAN		0x01a3
39 #define I8K_SMM_GET_FAN		0x00a3
40 #define I8K_SMM_GET_SPEED	0x02a3
41 #define I8K_SMM_GET_FAN_TYPE	0x03a3
42 #define I8K_SMM_GET_NOM_SPEED	0x04a3
43 #define I8K_SMM_GET_TEMP	0x10a3
44 #define I8K_SMM_GET_TEMP_TYPE	0x11a3
45 #define I8K_SMM_GET_DELL_SIG1	0xfea3
46 #define I8K_SMM_GET_DELL_SIG2	0xffa3
47 
48 #define I8K_FAN_MULT		30
49 #define I8K_FAN_MAX_RPM		30000
50 #define I8K_MAX_TEMP		127
51 
52 #define I8K_FN_NONE		0x00
53 #define I8K_FN_UP		0x01
54 #define I8K_FN_DOWN		0x02
55 #define I8K_FN_MUTE		0x04
56 #define I8K_FN_MASK		0x07
57 #define I8K_FN_SHIFT		8
58 
59 #define I8K_POWER_AC		0x05
60 #define I8K_POWER_BATTERY	0x01
61 
62 #define DELL_SMM_NO_TEMP	10
63 #define DELL_SMM_NO_FANS	3
64 
65 struct dell_smm_data {
66 	struct mutex i8k_mutex; /* lock for sensors writes */
67 	char bios_version[4];
68 	char bios_machineid[16];
69 	uint i8k_fan_mult;
70 	uint i8k_pwm_mult;
71 	uint i8k_fan_max;
72 	bool disallow_fan_type_call;
73 	bool disallow_fan_support;
74 	unsigned int manual_fan;
75 	unsigned int auto_fan;
76 	int temp_type[DELL_SMM_NO_TEMP];
77 	bool fan[DELL_SMM_NO_FANS];
78 	int fan_type[DELL_SMM_NO_FANS];
79 };
80 
81 MODULE_AUTHOR("Massimo Dal Zotto (dz@debian.org)");
82 MODULE_AUTHOR("Pali Rohár <pali@kernel.org>");
83 MODULE_DESCRIPTION("Dell laptop SMM BIOS hwmon driver");
84 MODULE_LICENSE("GPL");
85 MODULE_ALIAS("i8k");
86 
87 static bool force;
88 module_param(force, bool, 0);
89 MODULE_PARM_DESC(force, "Force loading without checking for supported models");
90 
91 static bool ignore_dmi;
92 module_param(ignore_dmi, bool, 0);
93 MODULE_PARM_DESC(ignore_dmi, "Continue probing hardware even if DMI data does not match");
94 
95 #if IS_ENABLED(CONFIG_I8K)
96 static bool restricted = true;
97 module_param(restricted, bool, 0);
98 MODULE_PARM_DESC(restricted, "Restrict fan control and serial number to CAP_SYS_ADMIN (default: 1)");
99 
100 static bool power_status;
101 module_param(power_status, bool, 0600);
102 MODULE_PARM_DESC(power_status, "Report power status in /proc/i8k (default: 0)");
103 #endif
104 
105 static uint fan_mult;
106 module_param(fan_mult, uint, 0);
107 MODULE_PARM_DESC(fan_mult, "Factor to multiply fan speed with (default: autodetect)");
108 
109 static uint fan_max;
110 module_param(fan_max, uint, 0);
111 MODULE_PARM_DESC(fan_max, "Maximum configurable fan speed (default: autodetect)");
112 
113 struct smm_regs {
114 	unsigned int eax;
115 	unsigned int ebx __packed;
116 	unsigned int ecx __packed;
117 	unsigned int edx __packed;
118 	unsigned int esi __packed;
119 	unsigned int edi __packed;
120 };
121 
122 static const char * const temp_labels[] = {
123 	"CPU",
124 	"GPU",
125 	"SODIMM",
126 	"Other",
127 	"Ambient",
128 	"Other",
129 };
130 
131 static const char * const fan_labels[] = {
132 	"Processor Fan",
133 	"Motherboard Fan",
134 	"Video Fan",
135 	"Power Supply Fan",
136 	"Chipset Fan",
137 	"Other Fan",
138 };
139 
140 static const char * const docking_labels[] = {
141 	"Docking Processor Fan",
142 	"Docking Motherboard Fan",
143 	"Docking Video Fan",
144 	"Docking Power Supply Fan",
145 	"Docking Chipset Fan",
146 	"Docking Other Fan",
147 };
148 
149 static inline const char __init *i8k_get_dmi_data(int field)
150 {
151 	const char *dmi_data = dmi_get_system_info(field);
152 
153 	return dmi_data && *dmi_data ? dmi_data : "?";
154 }
155 
156 /*
157  * Call the System Management Mode BIOS. Code provided by Jonathan Buzzard.
158  */
159 static int i8k_smm_func(void *par)
160 {
161 	ktime_t calltime = ktime_get();
162 	struct smm_regs *regs = par;
163 	int eax = regs->eax;
164 	int ebx = regs->ebx;
165 	long long duration;
166 	int rc;
167 
168 	/* SMM requires CPU 0 */
169 	if (smp_processor_id() != 0)
170 		return -EBUSY;
171 
172 #if defined(CONFIG_X86_64)
173 	asm volatile("pushq %%rax\n\t"
174 		"movl 0(%%rax),%%edx\n\t"
175 		"pushq %%rdx\n\t"
176 		"movl 4(%%rax),%%ebx\n\t"
177 		"movl 8(%%rax),%%ecx\n\t"
178 		"movl 12(%%rax),%%edx\n\t"
179 		"movl 16(%%rax),%%esi\n\t"
180 		"movl 20(%%rax),%%edi\n\t"
181 		"popq %%rax\n\t"
182 		"out %%al,$0xb2\n\t"
183 		"out %%al,$0x84\n\t"
184 		"xchgq %%rax,(%%rsp)\n\t"
185 		"movl %%ebx,4(%%rax)\n\t"
186 		"movl %%ecx,8(%%rax)\n\t"
187 		"movl %%edx,12(%%rax)\n\t"
188 		"movl %%esi,16(%%rax)\n\t"
189 		"movl %%edi,20(%%rax)\n\t"
190 		"popq %%rdx\n\t"
191 		"movl %%edx,0(%%rax)\n\t"
192 		"pushfq\n\t"
193 		"popq %%rax\n\t"
194 		"andl $1,%%eax\n"
195 		: "=a"(rc)
196 		:    "a"(regs)
197 		:    "%ebx", "%ecx", "%edx", "%esi", "%edi", "memory");
198 #else
199 	asm volatile("pushl %%eax\n\t"
200 	    "movl 0(%%eax),%%edx\n\t"
201 	    "push %%edx\n\t"
202 	    "movl 4(%%eax),%%ebx\n\t"
203 	    "movl 8(%%eax),%%ecx\n\t"
204 	    "movl 12(%%eax),%%edx\n\t"
205 	    "movl 16(%%eax),%%esi\n\t"
206 	    "movl 20(%%eax),%%edi\n\t"
207 	    "popl %%eax\n\t"
208 	    "out %%al,$0xb2\n\t"
209 	    "out %%al,$0x84\n\t"
210 	    "xchgl %%eax,(%%esp)\n\t"
211 	    "movl %%ebx,4(%%eax)\n\t"
212 	    "movl %%ecx,8(%%eax)\n\t"
213 	    "movl %%edx,12(%%eax)\n\t"
214 	    "movl %%esi,16(%%eax)\n\t"
215 	    "movl %%edi,20(%%eax)\n\t"
216 	    "popl %%edx\n\t"
217 	    "movl %%edx,0(%%eax)\n\t"
218 	    "lahf\n\t"
219 	    "shrl $8,%%eax\n\t"
220 	    "andl $1,%%eax\n"
221 	    : "=a"(rc)
222 	    :    "a"(regs)
223 	    :    "%ebx", "%ecx", "%edx", "%esi", "%edi", "memory");
224 #endif
225 	if (rc != 0 || (regs->eax & 0xffff) == 0xffff || regs->eax == eax)
226 		rc = -EINVAL;
227 
228 	duration = ktime_us_delta(ktime_get(), calltime);
229 	pr_debug("smm(0x%.4x 0x%.4x) = 0x%.4x  (took %7lld usecs)\n", eax, ebx,
230 		 (rc ? 0xffff : regs->eax & 0xffff), duration);
231 
232 	return rc;
233 }
234 
235 /*
236  * Call the System Management Mode BIOS.
237  */
238 static int i8k_smm(struct smm_regs *regs)
239 {
240 	int ret;
241 
242 	cpus_read_lock();
243 	ret = smp_call_on_cpu(0, i8k_smm_func, regs, true);
244 	cpus_read_unlock();
245 
246 	return ret;
247 }
248 
249 /*
250  * Read the fan status.
251  */
252 static int i8k_get_fan_status(const struct dell_smm_data *data, int fan)
253 {
254 	struct smm_regs regs = { .eax = I8K_SMM_GET_FAN, };
255 
256 	if (data->disallow_fan_support)
257 		return -EINVAL;
258 
259 	regs.ebx = fan & 0xff;
260 	return i8k_smm(&regs) ? : regs.eax & 0xff;
261 }
262 
263 /*
264  * Read the fan speed in RPM.
265  */
266 static int i8k_get_fan_speed(const struct dell_smm_data *data, int fan)
267 {
268 	struct smm_regs regs = { .eax = I8K_SMM_GET_SPEED, };
269 
270 	if (data->disallow_fan_support)
271 		return -EINVAL;
272 
273 	regs.ebx = fan & 0xff;
274 	return i8k_smm(&regs) ? : (regs.eax & 0xffff) * data->i8k_fan_mult;
275 }
276 
277 /*
278  * Read the fan type.
279  */
280 static int _i8k_get_fan_type(const struct dell_smm_data *data, int fan)
281 {
282 	struct smm_regs regs = { .eax = I8K_SMM_GET_FAN_TYPE, };
283 
284 	if (data->disallow_fan_support || data->disallow_fan_type_call)
285 		return -EINVAL;
286 
287 	regs.ebx = fan & 0xff;
288 	return i8k_smm(&regs) ? : regs.eax & 0xff;
289 }
290 
291 static int i8k_get_fan_type(struct dell_smm_data *data, int fan)
292 {
293 	/* I8K_SMM_GET_FAN_TYPE SMM call is expensive, so cache values */
294 	if (data->fan_type[fan] == INT_MIN)
295 		data->fan_type[fan] = _i8k_get_fan_type(data, fan);
296 
297 	return data->fan_type[fan];
298 }
299 
300 /*
301  * Read the fan nominal rpm for specific fan speed.
302  */
303 static int __init i8k_get_fan_nominal_speed(const struct dell_smm_data *data, int fan, int speed)
304 {
305 	struct smm_regs regs = { .eax = I8K_SMM_GET_NOM_SPEED, };
306 
307 	if (data->disallow_fan_support)
308 		return -EINVAL;
309 
310 	regs.ebx = (fan & 0xff) | (speed << 8);
311 	return i8k_smm(&regs) ? : (regs.eax & 0xffff) * data->i8k_fan_mult;
312 }
313 
314 /*
315  * Enable or disable automatic BIOS fan control support
316  */
317 static int i8k_enable_fan_auto_mode(const struct dell_smm_data *data, bool enable)
318 {
319 	struct smm_regs regs = { };
320 
321 	if (data->disallow_fan_support)
322 		return -EINVAL;
323 
324 	regs.eax = enable ? data->auto_fan : data->manual_fan;
325 	return i8k_smm(&regs);
326 }
327 
328 /*
329  * Set the fan speed (off, low, high). Returns the new fan status.
330  */
331 static int i8k_set_fan(const struct dell_smm_data *data, int fan, int speed)
332 {
333 	struct smm_regs regs = { .eax = I8K_SMM_SET_FAN, };
334 
335 	if (data->disallow_fan_support)
336 		return -EINVAL;
337 
338 	speed = (speed < 0) ? 0 : ((speed > data->i8k_fan_max) ? data->i8k_fan_max : speed);
339 	regs.ebx = (fan & 0xff) | (speed << 8);
340 
341 	return i8k_smm(&regs) ? : i8k_get_fan_status(data, fan);
342 }
343 
344 static int __init i8k_get_temp_type(int sensor)
345 {
346 	struct smm_regs regs = { .eax = I8K_SMM_GET_TEMP_TYPE, };
347 
348 	regs.ebx = sensor & 0xff;
349 	return i8k_smm(&regs) ? : regs.eax & 0xff;
350 }
351 
352 /*
353  * Read the cpu temperature.
354  */
355 static int _i8k_get_temp(int sensor)
356 {
357 	struct smm_regs regs = {
358 		.eax = I8K_SMM_GET_TEMP,
359 		.ebx = sensor & 0xff,
360 	};
361 
362 	return i8k_smm(&regs) ? : regs.eax & 0xff;
363 }
364 
365 static int i8k_get_temp(int sensor)
366 {
367 	int temp = _i8k_get_temp(sensor);
368 
369 	/*
370 	 * Sometimes the temperature sensor returns 0x99, which is out of range.
371 	 * In this case we retry (once) before returning an error.
372 	 # 1003655137 00000058 00005a4b
373 	 # 1003655138 00000099 00003a80 <--- 0x99 = 153 degrees
374 	 # 1003655139 00000054 00005c52
375 	 */
376 	if (temp == 0x99) {
377 		msleep(100);
378 		temp = _i8k_get_temp(sensor);
379 	}
380 	/*
381 	 * Return -ENODATA for all invalid temperatures.
382 	 *
383 	 * Known instances are the 0x99 value as seen above as well as
384 	 * 0xc1 (193), which may be returned when trying to read the GPU
385 	 * temperature if the system supports a GPU and it is currently
386 	 * turned off.
387 	 */
388 	if (temp > I8K_MAX_TEMP)
389 		return -ENODATA;
390 
391 	return temp;
392 }
393 
394 static int __init i8k_get_dell_signature(int req_fn)
395 {
396 	struct smm_regs regs = { .eax = req_fn, };
397 	int rc;
398 
399 	rc = i8k_smm(&regs);
400 	if (rc < 0)
401 		return rc;
402 
403 	return regs.eax == 1145651527 && regs.edx == 1145392204 ? 0 : -1;
404 }
405 
406 #if IS_ENABLED(CONFIG_I8K)
407 
408 /*
409  * Read the Fn key status.
410  */
411 static int i8k_get_fn_status(void)
412 {
413 	struct smm_regs regs = { .eax = I8K_SMM_FN_STATUS, };
414 	int rc;
415 
416 	rc = i8k_smm(&regs);
417 	if (rc < 0)
418 		return rc;
419 
420 	switch ((regs.eax >> I8K_FN_SHIFT) & I8K_FN_MASK) {
421 	case I8K_FN_UP:
422 		return I8K_VOL_UP;
423 	case I8K_FN_DOWN:
424 		return I8K_VOL_DOWN;
425 	case I8K_FN_MUTE:
426 		return I8K_VOL_MUTE;
427 	default:
428 		return 0;
429 	}
430 }
431 
432 /*
433  * Read the power status.
434  */
435 static int i8k_get_power_status(void)
436 {
437 	struct smm_regs regs = { .eax = I8K_SMM_POWER_STATUS, };
438 	int rc;
439 
440 	rc = i8k_smm(&regs);
441 	if (rc < 0)
442 		return rc;
443 
444 	return (regs.eax & 0xff) == I8K_POWER_AC ? I8K_AC : I8K_BATTERY;
445 }
446 
447 /*
448  * Procfs interface
449  */
450 
451 static int
452 i8k_ioctl_unlocked(struct file *fp, struct dell_smm_data *data, unsigned int cmd, unsigned long arg)
453 {
454 	int val = 0;
455 	int speed;
456 	unsigned char buff[16];
457 	int __user *argp = (int __user *)arg;
458 
459 	if (!argp)
460 		return -EINVAL;
461 
462 	switch (cmd) {
463 	case I8K_BIOS_VERSION:
464 		if (!isdigit(data->bios_version[0]) || !isdigit(data->bios_version[1]) ||
465 		    !isdigit(data->bios_version[2]))
466 			return -EINVAL;
467 
468 		val = (data->bios_version[0] << 16) |
469 				(data->bios_version[1] << 8) | data->bios_version[2];
470 		break;
471 
472 	case I8K_MACHINE_ID:
473 		if (restricted && !capable(CAP_SYS_ADMIN))
474 			return -EPERM;
475 
476 		memset(buff, 0, sizeof(buff));
477 		strscpy(buff, data->bios_machineid, sizeof(buff));
478 		break;
479 
480 	case I8K_FN_STATUS:
481 		val = i8k_get_fn_status();
482 		break;
483 
484 	case I8K_POWER_STATUS:
485 		val = i8k_get_power_status();
486 		break;
487 
488 	case I8K_GET_TEMP:
489 		val = i8k_get_temp(0);
490 		break;
491 
492 	case I8K_GET_SPEED:
493 		if (copy_from_user(&val, argp, sizeof(int)))
494 			return -EFAULT;
495 
496 		val = i8k_get_fan_speed(data, val);
497 		break;
498 
499 	case I8K_GET_FAN:
500 		if (copy_from_user(&val, argp, sizeof(int)))
501 			return -EFAULT;
502 
503 		val = i8k_get_fan_status(data, val);
504 		break;
505 
506 	case I8K_SET_FAN:
507 		if (restricted && !capable(CAP_SYS_ADMIN))
508 			return -EPERM;
509 
510 		if (copy_from_user(&val, argp, sizeof(int)))
511 			return -EFAULT;
512 
513 		if (copy_from_user(&speed, argp + 1, sizeof(int)))
514 			return -EFAULT;
515 
516 		val = i8k_set_fan(data, val, speed);
517 		break;
518 
519 	default:
520 		return -EINVAL;
521 	}
522 
523 	if (val < 0)
524 		return val;
525 
526 	switch (cmd) {
527 	case I8K_BIOS_VERSION:
528 		if (copy_to_user(argp, &val, 4))
529 			return -EFAULT;
530 
531 		break;
532 	case I8K_MACHINE_ID:
533 		if (copy_to_user(argp, buff, 16))
534 			return -EFAULT;
535 
536 		break;
537 	default:
538 		if (copy_to_user(argp, &val, sizeof(int)))
539 			return -EFAULT;
540 
541 		break;
542 	}
543 
544 	return 0;
545 }
546 
547 static long i8k_ioctl(struct file *fp, unsigned int cmd, unsigned long arg)
548 {
549 	struct dell_smm_data *data = PDE_DATA(file_inode(fp));
550 	long ret;
551 
552 	mutex_lock(&data->i8k_mutex);
553 	ret = i8k_ioctl_unlocked(fp, data, cmd, arg);
554 	mutex_unlock(&data->i8k_mutex);
555 
556 	return ret;
557 }
558 
559 /*
560  * Print the information for /proc/i8k.
561  */
562 static int i8k_proc_show(struct seq_file *seq, void *offset)
563 {
564 	struct dell_smm_data *data = seq->private;
565 	int fn_key, cpu_temp, ac_power;
566 	int left_fan, right_fan, left_speed, right_speed;
567 
568 	cpu_temp	= i8k_get_temp(0);				/* 11100 µs */
569 	left_fan	= i8k_get_fan_status(data, I8K_FAN_LEFT);	/*   580 µs */
570 	right_fan	= i8k_get_fan_status(data, I8K_FAN_RIGHT);	/*   580 µs */
571 	left_speed	= i8k_get_fan_speed(data, I8K_FAN_LEFT);	/*   580 µs */
572 	right_speed	= i8k_get_fan_speed(data, I8K_FAN_RIGHT);	/*   580 µs */
573 	fn_key		= i8k_get_fn_status();				/*   750 µs */
574 	if (power_status)
575 		ac_power = i8k_get_power_status();			/* 14700 µs */
576 	else
577 		ac_power = -1;
578 
579 	/*
580 	 * Info:
581 	 *
582 	 * 1)  Format version (this will change if format changes)
583 	 * 2)  BIOS version
584 	 * 3)  BIOS machine ID
585 	 * 4)  Cpu temperature
586 	 * 5)  Left fan status
587 	 * 6)  Right fan status
588 	 * 7)  Left fan speed
589 	 * 8)  Right fan speed
590 	 * 9)  AC power
591 	 * 10) Fn Key status
592 	 */
593 	seq_printf(seq, "%s %s %s %d %d %d %d %d %d %d\n",
594 		   I8K_PROC_FMT,
595 		   data->bios_version,
596 		   (restricted && !capable(CAP_SYS_ADMIN)) ? "-1" : data->bios_machineid,
597 		   cpu_temp,
598 		   left_fan, right_fan, left_speed, right_speed,
599 		   ac_power, fn_key);
600 
601 	return 0;
602 }
603 
604 static int i8k_open_fs(struct inode *inode, struct file *file)
605 {
606 	return single_open(file, i8k_proc_show, PDE_DATA(inode));
607 }
608 
609 static const struct proc_ops i8k_proc_ops = {
610 	.proc_open	= i8k_open_fs,
611 	.proc_read	= seq_read,
612 	.proc_lseek	= seq_lseek,
613 	.proc_release	= single_release,
614 	.proc_ioctl	= i8k_ioctl,
615 };
616 
617 static void i8k_exit_procfs(void *param)
618 {
619 	remove_proc_entry("i8k", NULL);
620 }
621 
622 static void __init i8k_init_procfs(struct device *dev)
623 {
624 	struct dell_smm_data *data = dev_get_drvdata(dev);
625 
626 	/* Register the proc entry */
627 	proc_create_data("i8k", 0, NULL, &i8k_proc_ops, data);
628 
629 	devm_add_action_or_reset(dev, i8k_exit_procfs, NULL);
630 }
631 
632 #else
633 
634 static void __init i8k_init_procfs(struct device *dev)
635 {
636 }
637 
638 #endif
639 
640 /*
641  * Hwmon interface
642  */
643 
644 static umode_t dell_smm_is_visible(const void *drvdata, enum hwmon_sensor_types type, u32 attr,
645 				   int channel)
646 {
647 	const struct dell_smm_data *data = drvdata;
648 
649 	switch (type) {
650 	case hwmon_temp:
651 		switch (attr) {
652 		case hwmon_temp_input:
653 		case hwmon_temp_label:
654 			if (data->temp_type[channel] >= 0)
655 				return 0444;
656 
657 			break;
658 		default:
659 			break;
660 		}
661 		break;
662 	case hwmon_fan:
663 		if (data->disallow_fan_support)
664 			break;
665 
666 		switch (attr) {
667 		case hwmon_fan_input:
668 			if (data->fan[channel])
669 				return 0444;
670 
671 			break;
672 		case hwmon_fan_label:
673 			if (data->fan[channel] && !data->disallow_fan_type_call)
674 				return 0444;
675 
676 			break;
677 		default:
678 			break;
679 		}
680 		break;
681 	case hwmon_pwm:
682 		if (data->disallow_fan_support)
683 			break;
684 
685 		switch (attr) {
686 		case hwmon_pwm_input:
687 			if (data->fan[channel])
688 				return 0644;
689 
690 			break;
691 		case hwmon_pwm_enable:
692 			if (data->auto_fan)
693 				/*
694 				 * There is no command for retrieve the current status
695 				 * from BIOS, and userspace/firmware itself can change
696 				 * it.
697 				 * Thus we can only provide write-only access for now.
698 				 */
699 				return 0200;
700 
701 			break;
702 		default:
703 			break;
704 		}
705 		break;
706 	default:
707 		break;
708 	}
709 
710 	return 0;
711 }
712 
713 static int dell_smm_read(struct device *dev, enum hwmon_sensor_types type, u32 attr, int channel,
714 			 long *val)
715 {
716 	struct dell_smm_data *data = dev_get_drvdata(dev);
717 	int ret;
718 
719 	switch (type) {
720 	case hwmon_temp:
721 		switch (attr) {
722 		case hwmon_temp_input:
723 			ret = i8k_get_temp(channel);
724 			if (ret < 0)
725 				return ret;
726 
727 			*val = ret * 1000;
728 
729 			return 0;
730 		default:
731 			break;
732 		}
733 		break;
734 	case hwmon_fan:
735 		switch (attr) {
736 		case hwmon_fan_input:
737 			ret = i8k_get_fan_speed(data, channel);
738 			if (ret < 0)
739 				return ret;
740 
741 			*val = ret;
742 
743 			return 0;
744 		default:
745 			break;
746 		}
747 		break;
748 	case hwmon_pwm:
749 		switch (attr) {
750 		case hwmon_pwm_input:
751 			ret = i8k_get_fan_status(data, channel);
752 			if (ret < 0)
753 				return ret;
754 
755 			*val = clamp_val(ret * data->i8k_pwm_mult, 0, 255);
756 
757 			return 0;
758 		default:
759 			break;
760 		}
761 		break;
762 	default:
763 		break;
764 	}
765 
766 	return -EOPNOTSUPP;
767 }
768 
769 static const char *dell_smm_fan_label(struct dell_smm_data *data, int channel)
770 {
771 	bool dock = false;
772 	int type = i8k_get_fan_type(data, channel);
773 
774 	if (type < 0)
775 		return ERR_PTR(type);
776 
777 	if (type & 0x10) {
778 		dock = true;
779 		type &= 0x0F;
780 	}
781 
782 	if (type >= ARRAY_SIZE(fan_labels))
783 		type = ARRAY_SIZE(fan_labels) - 1;
784 
785 	return dock ? docking_labels[type] : fan_labels[type];
786 }
787 
788 static int dell_smm_read_string(struct device *dev, enum hwmon_sensor_types type, u32 attr,
789 				int channel, const char **str)
790 {
791 	struct dell_smm_data *data = dev_get_drvdata(dev);
792 
793 	switch (type) {
794 	case hwmon_temp:
795 		switch (attr) {
796 		case hwmon_temp_label:
797 			*str = temp_labels[data->temp_type[channel]];
798 			return 0;
799 		default:
800 			break;
801 		}
802 		break;
803 	case hwmon_fan:
804 		switch (attr) {
805 		case hwmon_fan_label:
806 			*str = dell_smm_fan_label(data, channel);
807 			return PTR_ERR_OR_ZERO(*str);
808 		default:
809 			break;
810 		}
811 		break;
812 	default:
813 		break;
814 	}
815 
816 	return -EOPNOTSUPP;
817 }
818 
819 static int dell_smm_write(struct device *dev, enum hwmon_sensor_types type, u32 attr, int channel,
820 			  long val)
821 {
822 	struct dell_smm_data *data = dev_get_drvdata(dev);
823 	unsigned long pwm;
824 	bool enable;
825 	int err;
826 
827 	switch (type) {
828 	case hwmon_pwm:
829 		switch (attr) {
830 		case hwmon_pwm_input:
831 			pwm = clamp_val(DIV_ROUND_CLOSEST(val, data->i8k_pwm_mult), 0,
832 					data->i8k_fan_max);
833 
834 			mutex_lock(&data->i8k_mutex);
835 			err = i8k_set_fan(data, channel, pwm);
836 			mutex_unlock(&data->i8k_mutex);
837 
838 			if (err < 0)
839 				return err;
840 
841 			return 0;
842 		case hwmon_pwm_enable:
843 			if (!val)
844 				return -EINVAL;
845 
846 			if (val == 1)
847 				enable = false;
848 			else
849 				enable = true;
850 
851 			mutex_lock(&data->i8k_mutex);
852 			err = i8k_enable_fan_auto_mode(data, enable);
853 			mutex_unlock(&data->i8k_mutex);
854 
855 			if (err < 0)
856 				return err;
857 
858 			return 0;
859 		default:
860 			break;
861 		}
862 		break;
863 	default:
864 		break;
865 	}
866 
867 	return -EOPNOTSUPP;
868 }
869 
870 static const struct hwmon_ops dell_smm_ops = {
871 	.is_visible = dell_smm_is_visible,
872 	.read = dell_smm_read,
873 	.read_string = dell_smm_read_string,
874 	.write = dell_smm_write,
875 };
876 
877 static const struct hwmon_channel_info *dell_smm_info[] = {
878 	HWMON_CHANNEL_INFO(chip, HWMON_C_REGISTER_TZ),
879 	HWMON_CHANNEL_INFO(temp,
880 			   HWMON_T_INPUT | HWMON_T_LABEL,
881 			   HWMON_T_INPUT | HWMON_T_LABEL,
882 			   HWMON_T_INPUT | HWMON_T_LABEL,
883 			   HWMON_T_INPUT | HWMON_T_LABEL,
884 			   HWMON_T_INPUT | HWMON_T_LABEL,
885 			   HWMON_T_INPUT | HWMON_T_LABEL,
886 			   HWMON_T_INPUT | HWMON_T_LABEL,
887 			   HWMON_T_INPUT | HWMON_T_LABEL,
888 			   HWMON_T_INPUT | HWMON_T_LABEL,
889 			   HWMON_T_INPUT | HWMON_T_LABEL
890 			   ),
891 	HWMON_CHANNEL_INFO(fan,
892 			   HWMON_F_INPUT | HWMON_F_LABEL,
893 			   HWMON_F_INPUT | HWMON_F_LABEL,
894 			   HWMON_F_INPUT | HWMON_F_LABEL
895 			   ),
896 	HWMON_CHANNEL_INFO(pwm,
897 			   HWMON_PWM_INPUT | HWMON_PWM_ENABLE,
898 			   HWMON_PWM_INPUT,
899 			   HWMON_PWM_INPUT
900 			   ),
901 	NULL
902 };
903 
904 static const struct hwmon_chip_info dell_smm_chip_info = {
905 	.ops = &dell_smm_ops,
906 	.info = dell_smm_info,
907 };
908 
909 static int __init dell_smm_init_hwmon(struct device *dev)
910 {
911 	struct dell_smm_data *data = dev_get_drvdata(dev);
912 	struct device *dell_smm_hwmon_dev;
913 	int i, err;
914 
915 	for (i = 0; i < DELL_SMM_NO_TEMP; i++) {
916 		data->temp_type[i] = i8k_get_temp_type(i);
917 		if (data->temp_type[i] < 0)
918 			continue;
919 
920 		if (data->temp_type[i] >= ARRAY_SIZE(temp_labels))
921 			data->temp_type[i] = ARRAY_SIZE(temp_labels) - 1;
922 	}
923 
924 	for (i = 0; i < DELL_SMM_NO_FANS; i++) {
925 		data->fan_type[i] = INT_MIN;
926 		err = i8k_get_fan_status(data, i);
927 		if (err < 0)
928 			err = i8k_get_fan_type(data, i);
929 		if (err >= 0)
930 			data->fan[i] = true;
931 	}
932 
933 	dell_smm_hwmon_dev = devm_hwmon_device_register_with_info(dev, "dell_smm", data,
934 								  &dell_smm_chip_info, NULL);
935 
936 	return PTR_ERR_OR_ZERO(dell_smm_hwmon_dev);
937 }
938 
939 struct i8k_config_data {
940 	uint fan_mult;
941 	uint fan_max;
942 };
943 
944 enum i8k_configs {
945 	DELL_LATITUDE_D520,
946 	DELL_PRECISION_490,
947 	DELL_STUDIO,
948 	DELL_XPS,
949 };
950 
951 static const struct i8k_config_data i8k_config_data[] __initconst = {
952 	[DELL_LATITUDE_D520] = {
953 		.fan_mult = 1,
954 		.fan_max = I8K_FAN_TURBO,
955 	},
956 	[DELL_PRECISION_490] = {
957 		.fan_mult = 1,
958 		.fan_max = I8K_FAN_TURBO,
959 	},
960 	[DELL_STUDIO] = {
961 		.fan_mult = 1,
962 		.fan_max = I8K_FAN_HIGH,
963 	},
964 	[DELL_XPS] = {
965 		.fan_mult = 1,
966 		.fan_max = I8K_FAN_HIGH,
967 	},
968 };
969 
970 static const struct dmi_system_id i8k_dmi_table[] __initconst = {
971 	{
972 		.ident = "Dell Inspiron",
973 		.matches = {
974 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer"),
975 			DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron"),
976 		},
977 	},
978 	{
979 		.ident = "Dell Latitude",
980 		.matches = {
981 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer"),
982 			DMI_MATCH(DMI_PRODUCT_NAME, "Latitude"),
983 		},
984 	},
985 	{
986 		.ident = "Dell Inspiron 2",
987 		.matches = {
988 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
989 			DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron"),
990 		},
991 	},
992 	{
993 		.ident = "Dell Latitude D520",
994 		.matches = {
995 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
996 			DMI_MATCH(DMI_PRODUCT_NAME, "Latitude D520"),
997 		},
998 		.driver_data = (void *)&i8k_config_data[DELL_LATITUDE_D520],
999 	},
1000 	{
1001 		.ident = "Dell Latitude 2",
1002 		.matches = {
1003 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1004 			DMI_MATCH(DMI_PRODUCT_NAME, "Latitude"),
1005 		},
1006 	},
1007 	{	/* UK Inspiron 6400  */
1008 		.ident = "Dell Inspiron 3",
1009 		.matches = {
1010 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1011 			DMI_MATCH(DMI_PRODUCT_NAME, "MM061"),
1012 		},
1013 	},
1014 	{
1015 		.ident = "Dell Inspiron 3",
1016 		.matches = {
1017 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1018 			DMI_MATCH(DMI_PRODUCT_NAME, "MP061"),
1019 		},
1020 	},
1021 	{
1022 		.ident = "Dell Precision 490",
1023 		.matches = {
1024 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1025 			DMI_MATCH(DMI_PRODUCT_NAME,
1026 				  "Precision WorkStation 490"),
1027 		},
1028 		.driver_data = (void *)&i8k_config_data[DELL_PRECISION_490],
1029 	},
1030 	{
1031 		.ident = "Dell Precision",
1032 		.matches = {
1033 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1034 			DMI_MATCH(DMI_PRODUCT_NAME, "Precision"),
1035 		},
1036 	},
1037 	{
1038 		.ident = "Dell Vostro",
1039 		.matches = {
1040 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1041 			DMI_MATCH(DMI_PRODUCT_NAME, "Vostro"),
1042 		},
1043 	},
1044 	{
1045 		.ident = "Dell Studio",
1046 		.matches = {
1047 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1048 			DMI_MATCH(DMI_PRODUCT_NAME, "Studio"),
1049 		},
1050 		.driver_data = (void *)&i8k_config_data[DELL_STUDIO],
1051 	},
1052 	{
1053 		.ident = "Dell XPS M140",
1054 		.matches = {
1055 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1056 			DMI_MATCH(DMI_PRODUCT_NAME, "MXC051"),
1057 		},
1058 		.driver_data = (void *)&i8k_config_data[DELL_XPS],
1059 	},
1060 	{
1061 		.ident = "Dell XPS",
1062 		.matches = {
1063 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1064 			DMI_MATCH(DMI_PRODUCT_NAME, "XPS"),
1065 		},
1066 	},
1067 	{ }
1068 };
1069 
1070 MODULE_DEVICE_TABLE(dmi, i8k_dmi_table);
1071 
1072 /*
1073  * On some machines once I8K_SMM_GET_FAN_TYPE is issued then CPU fan speed
1074  * randomly going up and down due to bug in Dell SMM or BIOS. Here is blacklist
1075  * of affected Dell machines for which we disallow I8K_SMM_GET_FAN_TYPE call.
1076  * See bug: https://bugzilla.kernel.org/show_bug.cgi?id=100121
1077  */
1078 static const struct dmi_system_id i8k_blacklist_fan_type_dmi_table[] __initconst = {
1079 	{
1080 		.ident = "Dell Studio XPS 8000",
1081 		.matches = {
1082 			DMI_EXACT_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1083 			DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Studio XPS 8000"),
1084 		},
1085 	},
1086 	{
1087 		.ident = "Dell Studio XPS 8100",
1088 		.matches = {
1089 			DMI_EXACT_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1090 			DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Studio XPS 8100"),
1091 		},
1092 	},
1093 	{
1094 		.ident = "Dell Inspiron 580",
1095 		.matches = {
1096 			DMI_EXACT_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1097 			DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Inspiron 580 "),
1098 		},
1099 	},
1100 	{ }
1101 };
1102 
1103 /*
1104  * On some machines all fan related SMM functions implemented by Dell BIOS
1105  * firmware freeze kernel for about 500ms. Until Dell fixes these problems fan
1106  * support for affected blacklisted Dell machines stay disabled.
1107  * See bug: https://bugzilla.kernel.org/show_bug.cgi?id=195751
1108  */
1109 static const struct dmi_system_id i8k_blacklist_fan_support_dmi_table[] __initconst = {
1110 	{
1111 		.ident = "Dell Inspiron 7720",
1112 		.matches = {
1113 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1114 			DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Inspiron 7720"),
1115 		},
1116 	},
1117 	{
1118 		.ident = "Dell Vostro 3360",
1119 		.matches = {
1120 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1121 			DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Vostro 3360"),
1122 		},
1123 	},
1124 	{
1125 		.ident = "Dell XPS13 9333",
1126 		.matches = {
1127 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1128 			DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "XPS13 9333"),
1129 		},
1130 	},
1131 	{
1132 		.ident = "Dell XPS 15 L502X",
1133 		.matches = {
1134 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1135 			DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Dell System XPS L502X"),
1136 		},
1137 	},
1138 	{ }
1139 };
1140 
1141 struct i8k_fan_control_data {
1142 	unsigned int manual_fan;
1143 	unsigned int auto_fan;
1144 };
1145 
1146 enum i8k_fan_controls {
1147 	I8K_FAN_34A3_35A3,
1148 };
1149 
1150 static const struct i8k_fan_control_data i8k_fan_control_data[] __initconst = {
1151 	[I8K_FAN_34A3_35A3] = {
1152 		.manual_fan = 0x34a3,
1153 		.auto_fan = 0x35a3,
1154 	},
1155 };
1156 
1157 static const struct dmi_system_id i8k_whitelist_fan_control[] __initconst = {
1158 	{
1159 		.ident = "Dell Latitude 5480",
1160 		.matches = {
1161 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1162 			DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Latitude 5480"),
1163 		},
1164 		.driver_data = (void *)&i8k_fan_control_data[I8K_FAN_34A3_35A3],
1165 	},
1166 	{
1167 		.ident = "Dell Latitude E6440",
1168 		.matches = {
1169 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1170 			DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Latitude E6440"),
1171 		},
1172 		.driver_data = (void *)&i8k_fan_control_data[I8K_FAN_34A3_35A3],
1173 	},
1174 	{
1175 		.ident = "Dell Latitude E7440",
1176 		.matches = {
1177 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1178 			DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Latitude E7440"),
1179 		},
1180 		.driver_data = (void *)&i8k_fan_control_data[I8K_FAN_34A3_35A3],
1181 	},
1182 	{
1183 		.ident = "Dell Precision 5530",
1184 		.matches = {
1185 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1186 			DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Precision 5530"),
1187 		},
1188 		.driver_data = (void *)&i8k_fan_control_data[I8K_FAN_34A3_35A3],
1189 	},
1190 	{
1191 		.ident = "Dell Precision 7510",
1192 		.matches = {
1193 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1194 			DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Precision 7510"),
1195 		},
1196 		.driver_data = (void *)&i8k_fan_control_data[I8K_FAN_34A3_35A3],
1197 	},
1198 	{ }
1199 };
1200 
1201 static int __init dell_smm_probe(struct platform_device *pdev)
1202 {
1203 	struct dell_smm_data *data;
1204 	const struct dmi_system_id *id, *fan_control;
1205 	int fan, ret;
1206 
1207 	data = devm_kzalloc(&pdev->dev, sizeof(struct dell_smm_data), GFP_KERNEL);
1208 	if (!data)
1209 		return -ENOMEM;
1210 
1211 	mutex_init(&data->i8k_mutex);
1212 	data->i8k_fan_mult = I8K_FAN_MULT;
1213 	data->i8k_fan_max = I8K_FAN_HIGH;
1214 	platform_set_drvdata(pdev, data);
1215 
1216 	if (dmi_check_system(i8k_blacklist_fan_support_dmi_table)) {
1217 		dev_warn(&pdev->dev, "broken Dell BIOS detected, disallow fan support\n");
1218 		if (!force)
1219 			data->disallow_fan_support = true;
1220 	}
1221 
1222 	if (dmi_check_system(i8k_blacklist_fan_type_dmi_table)) {
1223 		dev_warn(&pdev->dev, "broken Dell BIOS detected, disallow fan type call\n");
1224 		if (!force)
1225 			data->disallow_fan_type_call = true;
1226 	}
1227 
1228 	strscpy(data->bios_version, i8k_get_dmi_data(DMI_BIOS_VERSION),
1229 		sizeof(data->bios_version));
1230 	strscpy(data->bios_machineid, i8k_get_dmi_data(DMI_PRODUCT_SERIAL),
1231 		sizeof(data->bios_machineid));
1232 
1233 	/*
1234 	 * Set fan multiplier and maximal fan speed from dmi config
1235 	 * Values specified in module parameters override values from dmi
1236 	 */
1237 	id = dmi_first_match(i8k_dmi_table);
1238 	if (id && id->driver_data) {
1239 		const struct i8k_config_data *conf = id->driver_data;
1240 
1241 		if (!fan_mult && conf->fan_mult)
1242 			fan_mult = conf->fan_mult;
1243 
1244 		if (!fan_max && conf->fan_max)
1245 			fan_max = conf->fan_max;
1246 	}
1247 
1248 	data->i8k_fan_max = fan_max ? : I8K_FAN_HIGH;	/* Must not be 0 */
1249 	data->i8k_pwm_mult = DIV_ROUND_UP(255, data->i8k_fan_max);
1250 
1251 	fan_control = dmi_first_match(i8k_whitelist_fan_control);
1252 	if (fan_control && fan_control->driver_data) {
1253 		const struct i8k_fan_control_data *control = fan_control->driver_data;
1254 
1255 		data->manual_fan = control->manual_fan;
1256 		data->auto_fan = control->auto_fan;
1257 		dev_info(&pdev->dev, "enabling support for setting automatic/manual fan control\n");
1258 	}
1259 
1260 	if (!fan_mult) {
1261 		/*
1262 		 * Autodetect fan multiplier based on nominal rpm
1263 		 * If fan reports rpm value too high then set multiplier to 1
1264 		 */
1265 		for (fan = 0; fan < DELL_SMM_NO_FANS; ++fan) {
1266 			ret = i8k_get_fan_nominal_speed(data, fan, data->i8k_fan_max);
1267 			if (ret < 0)
1268 				continue;
1269 
1270 			if (ret > I8K_FAN_MAX_RPM)
1271 				data->i8k_fan_mult = 1;
1272 			break;
1273 		}
1274 	} else {
1275 		/* Fan multiplier was specified in module param or in dmi */
1276 		data->i8k_fan_mult = fan_mult;
1277 	}
1278 
1279 	ret = dell_smm_init_hwmon(&pdev->dev);
1280 	if (ret)
1281 		return ret;
1282 
1283 	i8k_init_procfs(&pdev->dev);
1284 
1285 	return 0;
1286 }
1287 
1288 static struct platform_driver dell_smm_driver = {
1289 	.driver		= {
1290 		.name	= KBUILD_MODNAME,
1291 	},
1292 };
1293 
1294 static struct platform_device *dell_smm_device;
1295 
1296 /*
1297  * Probe for the presence of a supported laptop.
1298  */
1299 static int __init i8k_init(void)
1300 {
1301 	/*
1302 	 * Get DMI information
1303 	 */
1304 	if (!dmi_check_system(i8k_dmi_table)) {
1305 		if (!ignore_dmi && !force)
1306 			return -ENODEV;
1307 
1308 		pr_info("not running on a supported Dell system.\n");
1309 		pr_info("vendor=%s, model=%s, version=%s\n",
1310 			i8k_get_dmi_data(DMI_SYS_VENDOR),
1311 			i8k_get_dmi_data(DMI_PRODUCT_NAME),
1312 			i8k_get_dmi_data(DMI_BIOS_VERSION));
1313 	}
1314 
1315 	/*
1316 	 * Get SMM Dell signature
1317 	 */
1318 	if (i8k_get_dell_signature(I8K_SMM_GET_DELL_SIG1) &&
1319 	    i8k_get_dell_signature(I8K_SMM_GET_DELL_SIG2)) {
1320 		pr_err("unable to get SMM Dell signature\n");
1321 		if (!force)
1322 			return -ENODEV;
1323 	}
1324 
1325 	dell_smm_device = platform_create_bundle(&dell_smm_driver, dell_smm_probe, NULL, 0, NULL,
1326 						 0);
1327 
1328 	return PTR_ERR_OR_ZERO(dell_smm_device);
1329 }
1330 
1331 static void __exit i8k_exit(void)
1332 {
1333 	platform_device_unregister(dell_smm_device);
1334 	platform_driver_unregister(&dell_smm_driver);
1335 }
1336 
1337 module_init(i8k_init);
1338 module_exit(i8k_exit);
1339