xref: /linux/drivers/cpufreq/acpi-cpufreq.c (revision 4f2c0a4acffbec01079c28f839422e64ddeff004)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * acpi-cpufreq.c - ACPI Processor P-States Driver
4  *
5  *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
6  *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
7  *  Copyright (C) 2002 - 2004 Dominik Brodowski <linux@brodo.de>
8  *  Copyright (C) 2006       Denis Sadykov <denis.m.sadykov@intel.com>
9  */
10 
11 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
12 
13 #include <linux/kernel.h>
14 #include <linux/module.h>
15 #include <linux/init.h>
16 #include <linux/smp.h>
17 #include <linux/sched.h>
18 #include <linux/cpufreq.h>
19 #include <linux/compiler.h>
20 #include <linux/dmi.h>
21 #include <linux/slab.h>
22 
23 #include <linux/acpi.h>
24 #include <linux/io.h>
25 #include <linux/delay.h>
26 #include <linux/uaccess.h>
27 
28 #include <acpi/processor.h>
29 #include <acpi/cppc_acpi.h>
30 
31 #include <asm/msr.h>
32 #include <asm/processor.h>
33 #include <asm/cpufeature.h>
34 #include <asm/cpu_device_id.h>
35 
36 MODULE_AUTHOR("Paul Diefenbaugh, Dominik Brodowski");
37 MODULE_DESCRIPTION("ACPI Processor P-States Driver");
38 MODULE_LICENSE("GPL");
39 
40 enum {
41 	UNDEFINED_CAPABLE = 0,
42 	SYSTEM_INTEL_MSR_CAPABLE,
43 	SYSTEM_AMD_MSR_CAPABLE,
44 	SYSTEM_IO_CAPABLE,
45 };
46 
47 #define INTEL_MSR_RANGE		(0xffff)
48 #define AMD_MSR_RANGE		(0x7)
49 #define HYGON_MSR_RANGE		(0x7)
50 
51 #define MSR_K7_HWCR_CPB_DIS	(1ULL << 25)
52 
53 struct acpi_cpufreq_data {
54 	unsigned int resume;
55 	unsigned int cpu_feature;
56 	unsigned int acpi_perf_cpu;
57 	cpumask_var_t freqdomain_cpus;
58 	void (*cpu_freq_write)(struct acpi_pct_register *reg, u32 val);
59 	u32 (*cpu_freq_read)(struct acpi_pct_register *reg);
60 };
61 
62 /* acpi_perf_data is a pointer to percpu data. */
63 static struct acpi_processor_performance __percpu *acpi_perf_data;
64 
65 static inline struct acpi_processor_performance *to_perf_data(struct acpi_cpufreq_data *data)
66 {
67 	return per_cpu_ptr(acpi_perf_data, data->acpi_perf_cpu);
68 }
69 
70 static struct cpufreq_driver acpi_cpufreq_driver;
71 
72 static unsigned int acpi_pstate_strict;
73 
74 static bool boost_state(unsigned int cpu)
75 {
76 	u32 lo, hi;
77 	u64 msr;
78 
79 	switch (boot_cpu_data.x86_vendor) {
80 	case X86_VENDOR_INTEL:
81 	case X86_VENDOR_CENTAUR:
82 	case X86_VENDOR_ZHAOXIN:
83 		rdmsr_on_cpu(cpu, MSR_IA32_MISC_ENABLE, &lo, &hi);
84 		msr = lo | ((u64)hi << 32);
85 		return !(msr & MSR_IA32_MISC_ENABLE_TURBO_DISABLE);
86 	case X86_VENDOR_HYGON:
87 	case X86_VENDOR_AMD:
88 		rdmsr_on_cpu(cpu, MSR_K7_HWCR, &lo, &hi);
89 		msr = lo | ((u64)hi << 32);
90 		return !(msr & MSR_K7_HWCR_CPB_DIS);
91 	}
92 	return false;
93 }
94 
95 static int boost_set_msr(bool enable)
96 {
97 	u32 msr_addr;
98 	u64 msr_mask, val;
99 
100 	switch (boot_cpu_data.x86_vendor) {
101 	case X86_VENDOR_INTEL:
102 	case X86_VENDOR_CENTAUR:
103 	case X86_VENDOR_ZHAOXIN:
104 		msr_addr = MSR_IA32_MISC_ENABLE;
105 		msr_mask = MSR_IA32_MISC_ENABLE_TURBO_DISABLE;
106 		break;
107 	case X86_VENDOR_HYGON:
108 	case X86_VENDOR_AMD:
109 		msr_addr = MSR_K7_HWCR;
110 		msr_mask = MSR_K7_HWCR_CPB_DIS;
111 		break;
112 	default:
113 		return -EINVAL;
114 	}
115 
116 	rdmsrl(msr_addr, val);
117 
118 	if (enable)
119 		val &= ~msr_mask;
120 	else
121 		val |= msr_mask;
122 
123 	wrmsrl(msr_addr, val);
124 	return 0;
125 }
126 
127 static void boost_set_msr_each(void *p_en)
128 {
129 	bool enable = (bool) p_en;
130 
131 	boost_set_msr(enable);
132 }
133 
134 static int set_boost(struct cpufreq_policy *policy, int val)
135 {
136 	on_each_cpu_mask(policy->cpus, boost_set_msr_each,
137 			 (void *)(long)val, 1);
138 	pr_debug("CPU %*pbl: Core Boosting %sabled.\n",
139 		 cpumask_pr_args(policy->cpus), val ? "en" : "dis");
140 
141 	return 0;
142 }
143 
144 static ssize_t show_freqdomain_cpus(struct cpufreq_policy *policy, char *buf)
145 {
146 	struct acpi_cpufreq_data *data = policy->driver_data;
147 
148 	if (unlikely(!data))
149 		return -ENODEV;
150 
151 	return cpufreq_show_cpus(data->freqdomain_cpus, buf);
152 }
153 
154 cpufreq_freq_attr_ro(freqdomain_cpus);
155 
156 #ifdef CONFIG_X86_ACPI_CPUFREQ_CPB
157 static ssize_t store_cpb(struct cpufreq_policy *policy, const char *buf,
158 			 size_t count)
159 {
160 	int ret;
161 	unsigned int val = 0;
162 
163 	if (!acpi_cpufreq_driver.set_boost)
164 		return -EINVAL;
165 
166 	ret = kstrtouint(buf, 10, &val);
167 	if (ret || val > 1)
168 		return -EINVAL;
169 
170 	cpus_read_lock();
171 	set_boost(policy, val);
172 	cpus_read_unlock();
173 
174 	return count;
175 }
176 
177 static ssize_t show_cpb(struct cpufreq_policy *policy, char *buf)
178 {
179 	return sprintf(buf, "%u\n", acpi_cpufreq_driver.boost_enabled);
180 }
181 
182 cpufreq_freq_attr_rw(cpb);
183 #endif
184 
185 static int check_est_cpu(unsigned int cpuid)
186 {
187 	struct cpuinfo_x86 *cpu = &cpu_data(cpuid);
188 
189 	return cpu_has(cpu, X86_FEATURE_EST);
190 }
191 
192 static int check_amd_hwpstate_cpu(unsigned int cpuid)
193 {
194 	struct cpuinfo_x86 *cpu = &cpu_data(cpuid);
195 
196 	return cpu_has(cpu, X86_FEATURE_HW_PSTATE);
197 }
198 
199 static unsigned extract_io(struct cpufreq_policy *policy, u32 value)
200 {
201 	struct acpi_cpufreq_data *data = policy->driver_data;
202 	struct acpi_processor_performance *perf;
203 	int i;
204 
205 	perf = to_perf_data(data);
206 
207 	for (i = 0; i < perf->state_count; i++) {
208 		if (value == perf->states[i].status)
209 			return policy->freq_table[i].frequency;
210 	}
211 	return 0;
212 }
213 
214 static unsigned extract_msr(struct cpufreq_policy *policy, u32 msr)
215 {
216 	struct acpi_cpufreq_data *data = policy->driver_data;
217 	struct cpufreq_frequency_table *pos;
218 	struct acpi_processor_performance *perf;
219 
220 	if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD)
221 		msr &= AMD_MSR_RANGE;
222 	else if (boot_cpu_data.x86_vendor == X86_VENDOR_HYGON)
223 		msr &= HYGON_MSR_RANGE;
224 	else
225 		msr &= INTEL_MSR_RANGE;
226 
227 	perf = to_perf_data(data);
228 
229 	cpufreq_for_each_entry(pos, policy->freq_table)
230 		if (msr == perf->states[pos->driver_data].status)
231 			return pos->frequency;
232 	return policy->freq_table[0].frequency;
233 }
234 
235 static unsigned extract_freq(struct cpufreq_policy *policy, u32 val)
236 {
237 	struct acpi_cpufreq_data *data = policy->driver_data;
238 
239 	switch (data->cpu_feature) {
240 	case SYSTEM_INTEL_MSR_CAPABLE:
241 	case SYSTEM_AMD_MSR_CAPABLE:
242 		return extract_msr(policy, val);
243 	case SYSTEM_IO_CAPABLE:
244 		return extract_io(policy, val);
245 	default:
246 		return 0;
247 	}
248 }
249 
250 static u32 cpu_freq_read_intel(struct acpi_pct_register *not_used)
251 {
252 	u32 val, dummy __always_unused;
253 
254 	rdmsr(MSR_IA32_PERF_CTL, val, dummy);
255 	return val;
256 }
257 
258 static void cpu_freq_write_intel(struct acpi_pct_register *not_used, u32 val)
259 {
260 	u32 lo, hi;
261 
262 	rdmsr(MSR_IA32_PERF_CTL, lo, hi);
263 	lo = (lo & ~INTEL_MSR_RANGE) | (val & INTEL_MSR_RANGE);
264 	wrmsr(MSR_IA32_PERF_CTL, lo, hi);
265 }
266 
267 static u32 cpu_freq_read_amd(struct acpi_pct_register *not_used)
268 {
269 	u32 val, dummy __always_unused;
270 
271 	rdmsr(MSR_AMD_PERF_CTL, val, dummy);
272 	return val;
273 }
274 
275 static void cpu_freq_write_amd(struct acpi_pct_register *not_used, u32 val)
276 {
277 	wrmsr(MSR_AMD_PERF_CTL, val, 0);
278 }
279 
280 static u32 cpu_freq_read_io(struct acpi_pct_register *reg)
281 {
282 	u32 val;
283 
284 	acpi_os_read_port(reg->address, &val, reg->bit_width);
285 	return val;
286 }
287 
288 static void cpu_freq_write_io(struct acpi_pct_register *reg, u32 val)
289 {
290 	acpi_os_write_port(reg->address, val, reg->bit_width);
291 }
292 
293 struct drv_cmd {
294 	struct acpi_pct_register *reg;
295 	u32 val;
296 	union {
297 		void (*write)(struct acpi_pct_register *reg, u32 val);
298 		u32 (*read)(struct acpi_pct_register *reg);
299 	} func;
300 };
301 
302 /* Called via smp_call_function_single(), on the target CPU */
303 static void do_drv_read(void *_cmd)
304 {
305 	struct drv_cmd *cmd = _cmd;
306 
307 	cmd->val = cmd->func.read(cmd->reg);
308 }
309 
310 static u32 drv_read(struct acpi_cpufreq_data *data, const struct cpumask *mask)
311 {
312 	struct acpi_processor_performance *perf = to_perf_data(data);
313 	struct drv_cmd cmd = {
314 		.reg = &perf->control_register,
315 		.func.read = data->cpu_freq_read,
316 	};
317 	int err;
318 
319 	err = smp_call_function_any(mask, do_drv_read, &cmd, 1);
320 	WARN_ON_ONCE(err);	/* smp_call_function_any() was buggy? */
321 	return cmd.val;
322 }
323 
324 /* Called via smp_call_function_many(), on the target CPUs */
325 static void do_drv_write(void *_cmd)
326 {
327 	struct drv_cmd *cmd = _cmd;
328 
329 	cmd->func.write(cmd->reg, cmd->val);
330 }
331 
332 static void drv_write(struct acpi_cpufreq_data *data,
333 		      const struct cpumask *mask, u32 val)
334 {
335 	struct acpi_processor_performance *perf = to_perf_data(data);
336 	struct drv_cmd cmd = {
337 		.reg = &perf->control_register,
338 		.val = val,
339 		.func.write = data->cpu_freq_write,
340 	};
341 	int this_cpu;
342 
343 	this_cpu = get_cpu();
344 	if (cpumask_test_cpu(this_cpu, mask))
345 		do_drv_write(&cmd);
346 
347 	smp_call_function_many(mask, do_drv_write, &cmd, 1);
348 	put_cpu();
349 }
350 
351 static u32 get_cur_val(const struct cpumask *mask, struct acpi_cpufreq_data *data)
352 {
353 	u32 val;
354 
355 	if (unlikely(cpumask_empty(mask)))
356 		return 0;
357 
358 	val = drv_read(data, mask);
359 
360 	pr_debug("%s = %u\n", __func__, val);
361 
362 	return val;
363 }
364 
365 static unsigned int get_cur_freq_on_cpu(unsigned int cpu)
366 {
367 	struct acpi_cpufreq_data *data;
368 	struct cpufreq_policy *policy;
369 	unsigned int freq;
370 	unsigned int cached_freq;
371 
372 	pr_debug("%s (%d)\n", __func__, cpu);
373 
374 	policy = cpufreq_cpu_get_raw(cpu);
375 	if (unlikely(!policy))
376 		return 0;
377 
378 	data = policy->driver_data;
379 	if (unlikely(!data || !policy->freq_table))
380 		return 0;
381 
382 	cached_freq = policy->freq_table[to_perf_data(data)->state].frequency;
383 	freq = extract_freq(policy, get_cur_val(cpumask_of(cpu), data));
384 	if (freq != cached_freq) {
385 		/*
386 		 * The dreaded BIOS frequency change behind our back.
387 		 * Force set the frequency on next target call.
388 		 */
389 		data->resume = 1;
390 	}
391 
392 	pr_debug("cur freq = %u\n", freq);
393 
394 	return freq;
395 }
396 
397 static unsigned int check_freqs(struct cpufreq_policy *policy,
398 				const struct cpumask *mask, unsigned int freq)
399 {
400 	struct acpi_cpufreq_data *data = policy->driver_data;
401 	unsigned int cur_freq;
402 	unsigned int i;
403 
404 	for (i = 0; i < 100; i++) {
405 		cur_freq = extract_freq(policy, get_cur_val(mask, data));
406 		if (cur_freq == freq)
407 			return 1;
408 		udelay(10);
409 	}
410 	return 0;
411 }
412 
413 static int acpi_cpufreq_target(struct cpufreq_policy *policy,
414 			       unsigned int index)
415 {
416 	struct acpi_cpufreq_data *data = policy->driver_data;
417 	struct acpi_processor_performance *perf;
418 	const struct cpumask *mask;
419 	unsigned int next_perf_state = 0; /* Index into perf table */
420 	int result = 0;
421 
422 	if (unlikely(!data)) {
423 		return -ENODEV;
424 	}
425 
426 	perf = to_perf_data(data);
427 	next_perf_state = policy->freq_table[index].driver_data;
428 	if (perf->state == next_perf_state) {
429 		if (unlikely(data->resume)) {
430 			pr_debug("Called after resume, resetting to P%d\n",
431 				next_perf_state);
432 			data->resume = 0;
433 		} else {
434 			pr_debug("Already at target state (P%d)\n",
435 				next_perf_state);
436 			return 0;
437 		}
438 	}
439 
440 	/*
441 	 * The core won't allow CPUs to go away until the governor has been
442 	 * stopped, so we can rely on the stability of policy->cpus.
443 	 */
444 	mask = policy->shared_type == CPUFREQ_SHARED_TYPE_ANY ?
445 		cpumask_of(policy->cpu) : policy->cpus;
446 
447 	drv_write(data, mask, perf->states[next_perf_state].control);
448 
449 	if (acpi_pstate_strict) {
450 		if (!check_freqs(policy, mask,
451 				 policy->freq_table[index].frequency)) {
452 			pr_debug("%s (%d)\n", __func__, policy->cpu);
453 			result = -EAGAIN;
454 		}
455 	}
456 
457 	if (!result)
458 		perf->state = next_perf_state;
459 
460 	return result;
461 }
462 
463 static unsigned int acpi_cpufreq_fast_switch(struct cpufreq_policy *policy,
464 					     unsigned int target_freq)
465 {
466 	struct acpi_cpufreq_data *data = policy->driver_data;
467 	struct acpi_processor_performance *perf;
468 	struct cpufreq_frequency_table *entry;
469 	unsigned int next_perf_state, next_freq, index;
470 
471 	/*
472 	 * Find the closest frequency above target_freq.
473 	 */
474 	if (policy->cached_target_freq == target_freq)
475 		index = policy->cached_resolved_idx;
476 	else
477 		index = cpufreq_table_find_index_dl(policy, target_freq,
478 						    false);
479 
480 	entry = &policy->freq_table[index];
481 	next_freq = entry->frequency;
482 	next_perf_state = entry->driver_data;
483 
484 	perf = to_perf_data(data);
485 	if (perf->state == next_perf_state) {
486 		if (unlikely(data->resume))
487 			data->resume = 0;
488 		else
489 			return next_freq;
490 	}
491 
492 	data->cpu_freq_write(&perf->control_register,
493 			     perf->states[next_perf_state].control);
494 	perf->state = next_perf_state;
495 	return next_freq;
496 }
497 
498 static unsigned long
499 acpi_cpufreq_guess_freq(struct acpi_cpufreq_data *data, unsigned int cpu)
500 {
501 	struct acpi_processor_performance *perf;
502 
503 	perf = to_perf_data(data);
504 	if (cpu_khz) {
505 		/* search the closest match to cpu_khz */
506 		unsigned int i;
507 		unsigned long freq;
508 		unsigned long freqn = perf->states[0].core_frequency * 1000;
509 
510 		for (i = 0; i < (perf->state_count-1); i++) {
511 			freq = freqn;
512 			freqn = perf->states[i+1].core_frequency * 1000;
513 			if ((2 * cpu_khz) > (freqn + freq)) {
514 				perf->state = i;
515 				return freq;
516 			}
517 		}
518 		perf->state = perf->state_count-1;
519 		return freqn;
520 	} else {
521 		/* assume CPU is at P0... */
522 		perf->state = 0;
523 		return perf->states[0].core_frequency * 1000;
524 	}
525 }
526 
527 static void free_acpi_perf_data(void)
528 {
529 	unsigned int i;
530 
531 	/* Freeing a NULL pointer is OK, and alloc_percpu zeroes. */
532 	for_each_possible_cpu(i)
533 		free_cpumask_var(per_cpu_ptr(acpi_perf_data, i)
534 				 ->shared_cpu_map);
535 	free_percpu(acpi_perf_data);
536 }
537 
538 static int cpufreq_boost_online(unsigned int cpu)
539 {
540 	/*
541 	 * On the CPU_UP path we simply keep the boost-disable flag
542 	 * in sync with the current global state.
543 	 */
544 	return boost_set_msr(acpi_cpufreq_driver.boost_enabled);
545 }
546 
547 static int cpufreq_boost_down_prep(unsigned int cpu)
548 {
549 	/*
550 	 * Clear the boost-disable bit on the CPU_DOWN path so that
551 	 * this cpu cannot block the remaining ones from boosting.
552 	 */
553 	return boost_set_msr(1);
554 }
555 
556 /*
557  * acpi_cpufreq_early_init - initialize ACPI P-States library
558  *
559  * Initialize the ACPI P-States library (drivers/acpi/processor_perflib.c)
560  * in order to determine correct frequency and voltage pairings. We can
561  * do _PDC and _PSD and find out the processor dependency for the
562  * actual init that will happen later...
563  */
564 static int __init acpi_cpufreq_early_init(void)
565 {
566 	unsigned int i;
567 	pr_debug("%s\n", __func__);
568 
569 	acpi_perf_data = alloc_percpu(struct acpi_processor_performance);
570 	if (!acpi_perf_data) {
571 		pr_debug("Memory allocation error for acpi_perf_data.\n");
572 		return -ENOMEM;
573 	}
574 	for_each_possible_cpu(i) {
575 		if (!zalloc_cpumask_var_node(
576 			&per_cpu_ptr(acpi_perf_data, i)->shared_cpu_map,
577 			GFP_KERNEL, cpu_to_node(i))) {
578 
579 			/* Freeing a NULL pointer is OK: alloc_percpu zeroes. */
580 			free_acpi_perf_data();
581 			return -ENOMEM;
582 		}
583 	}
584 
585 	/* Do initialization in ACPI core */
586 	acpi_processor_preregister_performance(acpi_perf_data);
587 	return 0;
588 }
589 
590 #ifdef CONFIG_SMP
591 /*
592  * Some BIOSes do SW_ANY coordination internally, either set it up in hw
593  * or do it in BIOS firmware and won't inform about it to OS. If not
594  * detected, this has a side effect of making CPU run at a different speed
595  * than OS intended it to run at. Detect it and handle it cleanly.
596  */
597 static int bios_with_sw_any_bug;
598 
599 static int sw_any_bug_found(const struct dmi_system_id *d)
600 {
601 	bios_with_sw_any_bug = 1;
602 	return 0;
603 }
604 
605 static const struct dmi_system_id sw_any_bug_dmi_table[] = {
606 	{
607 		.callback = sw_any_bug_found,
608 		.ident = "Supermicro Server X6DLP",
609 		.matches = {
610 			DMI_MATCH(DMI_SYS_VENDOR, "Supermicro"),
611 			DMI_MATCH(DMI_BIOS_VERSION, "080010"),
612 			DMI_MATCH(DMI_PRODUCT_NAME, "X6DLP"),
613 		},
614 	},
615 	{ }
616 };
617 
618 static int acpi_cpufreq_blacklist(struct cpuinfo_x86 *c)
619 {
620 	/* Intel Xeon Processor 7100 Series Specification Update
621 	 * https://www.intel.com/Assets/PDF/specupdate/314554.pdf
622 	 * AL30: A Machine Check Exception (MCE) Occurring during an
623 	 * Enhanced Intel SpeedStep Technology Ratio Change May Cause
624 	 * Both Processor Cores to Lock Up. */
625 	if (c->x86_vendor == X86_VENDOR_INTEL) {
626 		if ((c->x86 == 15) &&
627 		    (c->x86_model == 6) &&
628 		    (c->x86_stepping == 8)) {
629 			pr_info("Intel(R) Xeon(R) 7100 Errata AL30, processors may lock up on frequency changes: disabling acpi-cpufreq\n");
630 			return -ENODEV;
631 		    }
632 		}
633 	return 0;
634 }
635 #endif
636 
637 #ifdef CONFIG_ACPI_CPPC_LIB
638 static u64 get_max_boost_ratio(unsigned int cpu)
639 {
640 	struct cppc_perf_caps perf_caps;
641 	u64 highest_perf, nominal_perf;
642 	int ret;
643 
644 	if (acpi_pstate_strict)
645 		return 0;
646 
647 	ret = cppc_get_perf_caps(cpu, &perf_caps);
648 	if (ret) {
649 		pr_debug("CPU%d: Unable to get performance capabilities (%d)\n",
650 			 cpu, ret);
651 		return 0;
652 	}
653 
654 	if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD)
655 		highest_perf = amd_get_highest_perf();
656 	else
657 		highest_perf = perf_caps.highest_perf;
658 
659 	nominal_perf = perf_caps.nominal_perf;
660 
661 	if (!highest_perf || !nominal_perf) {
662 		pr_debug("CPU%d: highest or nominal performance missing\n", cpu);
663 		return 0;
664 	}
665 
666 	if (highest_perf < nominal_perf) {
667 		pr_debug("CPU%d: nominal performance above highest\n", cpu);
668 		return 0;
669 	}
670 
671 	return div_u64(highest_perf << SCHED_CAPACITY_SHIFT, nominal_perf);
672 }
673 #else
674 static inline u64 get_max_boost_ratio(unsigned int cpu) { return 0; }
675 #endif
676 
677 static int acpi_cpufreq_cpu_init(struct cpufreq_policy *policy)
678 {
679 	struct cpufreq_frequency_table *freq_table;
680 	struct acpi_processor_performance *perf;
681 	struct acpi_cpufreq_data *data;
682 	unsigned int cpu = policy->cpu;
683 	struct cpuinfo_x86 *c = &cpu_data(cpu);
684 	unsigned int valid_states = 0;
685 	unsigned int result = 0;
686 	u64 max_boost_ratio;
687 	unsigned int i;
688 #ifdef CONFIG_SMP
689 	static int blacklisted;
690 #endif
691 
692 	pr_debug("%s\n", __func__);
693 
694 #ifdef CONFIG_SMP
695 	if (blacklisted)
696 		return blacklisted;
697 	blacklisted = acpi_cpufreq_blacklist(c);
698 	if (blacklisted)
699 		return blacklisted;
700 #endif
701 
702 	data = kzalloc(sizeof(*data), GFP_KERNEL);
703 	if (!data)
704 		return -ENOMEM;
705 
706 	if (!zalloc_cpumask_var(&data->freqdomain_cpus, GFP_KERNEL)) {
707 		result = -ENOMEM;
708 		goto err_free;
709 	}
710 
711 	perf = per_cpu_ptr(acpi_perf_data, cpu);
712 	data->acpi_perf_cpu = cpu;
713 	policy->driver_data = data;
714 
715 	if (cpu_has(c, X86_FEATURE_CONSTANT_TSC))
716 		acpi_cpufreq_driver.flags |= CPUFREQ_CONST_LOOPS;
717 
718 	result = acpi_processor_register_performance(perf, cpu);
719 	if (result)
720 		goto err_free_mask;
721 
722 	policy->shared_type = perf->shared_type;
723 
724 	/*
725 	 * Will let policy->cpus know about dependency only when software
726 	 * coordination is required.
727 	 */
728 	if (policy->shared_type == CPUFREQ_SHARED_TYPE_ALL ||
729 	    policy->shared_type == CPUFREQ_SHARED_TYPE_ANY) {
730 		cpumask_copy(policy->cpus, perf->shared_cpu_map);
731 	}
732 	cpumask_copy(data->freqdomain_cpus, perf->shared_cpu_map);
733 
734 #ifdef CONFIG_SMP
735 	dmi_check_system(sw_any_bug_dmi_table);
736 	if (bios_with_sw_any_bug && !policy_is_shared(policy)) {
737 		policy->shared_type = CPUFREQ_SHARED_TYPE_ALL;
738 		cpumask_copy(policy->cpus, topology_core_cpumask(cpu));
739 	}
740 
741 	if (check_amd_hwpstate_cpu(cpu) && boot_cpu_data.x86 < 0x19 &&
742 	    !acpi_pstate_strict) {
743 		cpumask_clear(policy->cpus);
744 		cpumask_set_cpu(cpu, policy->cpus);
745 		cpumask_copy(data->freqdomain_cpus,
746 			     topology_sibling_cpumask(cpu));
747 		policy->shared_type = CPUFREQ_SHARED_TYPE_HW;
748 		pr_info_once("overriding BIOS provided _PSD data\n");
749 	}
750 #endif
751 
752 	/* capability check */
753 	if (perf->state_count <= 1) {
754 		pr_debug("No P-States\n");
755 		result = -ENODEV;
756 		goto err_unreg;
757 	}
758 
759 	if (perf->control_register.space_id != perf->status_register.space_id) {
760 		result = -ENODEV;
761 		goto err_unreg;
762 	}
763 
764 	switch (perf->control_register.space_id) {
765 	case ACPI_ADR_SPACE_SYSTEM_IO:
766 		if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD &&
767 		    boot_cpu_data.x86 == 0xf) {
768 			pr_debug("AMD K8 systems must use native drivers.\n");
769 			result = -ENODEV;
770 			goto err_unreg;
771 		}
772 		pr_debug("SYSTEM IO addr space\n");
773 		data->cpu_feature = SYSTEM_IO_CAPABLE;
774 		data->cpu_freq_read = cpu_freq_read_io;
775 		data->cpu_freq_write = cpu_freq_write_io;
776 		break;
777 	case ACPI_ADR_SPACE_FIXED_HARDWARE:
778 		pr_debug("HARDWARE addr space\n");
779 		if (check_est_cpu(cpu)) {
780 			data->cpu_feature = SYSTEM_INTEL_MSR_CAPABLE;
781 			data->cpu_freq_read = cpu_freq_read_intel;
782 			data->cpu_freq_write = cpu_freq_write_intel;
783 			break;
784 		}
785 		if (check_amd_hwpstate_cpu(cpu)) {
786 			data->cpu_feature = SYSTEM_AMD_MSR_CAPABLE;
787 			data->cpu_freq_read = cpu_freq_read_amd;
788 			data->cpu_freq_write = cpu_freq_write_amd;
789 			break;
790 		}
791 		result = -ENODEV;
792 		goto err_unreg;
793 	default:
794 		pr_debug("Unknown addr space %d\n",
795 			(u32) (perf->control_register.space_id));
796 		result = -ENODEV;
797 		goto err_unreg;
798 	}
799 
800 	freq_table = kcalloc(perf->state_count + 1, sizeof(*freq_table),
801 			     GFP_KERNEL);
802 	if (!freq_table) {
803 		result = -ENOMEM;
804 		goto err_unreg;
805 	}
806 
807 	/* detect transition latency */
808 	policy->cpuinfo.transition_latency = 0;
809 	for (i = 0; i < perf->state_count; i++) {
810 		if ((perf->states[i].transition_latency * 1000) >
811 		    policy->cpuinfo.transition_latency)
812 			policy->cpuinfo.transition_latency =
813 			    perf->states[i].transition_latency * 1000;
814 	}
815 
816 	/* Check for high latency (>20uS) from buggy BIOSes, like on T42 */
817 	if (perf->control_register.space_id == ACPI_ADR_SPACE_FIXED_HARDWARE &&
818 	    policy->cpuinfo.transition_latency > 20 * 1000) {
819 		policy->cpuinfo.transition_latency = 20 * 1000;
820 		pr_info_once("P-state transition latency capped at 20 uS\n");
821 	}
822 
823 	/* table init */
824 	for (i = 0; i < perf->state_count; i++) {
825 		if (i > 0 && perf->states[i].core_frequency >=
826 		    freq_table[valid_states-1].frequency / 1000)
827 			continue;
828 
829 		freq_table[valid_states].driver_data = i;
830 		freq_table[valid_states].frequency =
831 		    perf->states[i].core_frequency * 1000;
832 		valid_states++;
833 	}
834 	freq_table[valid_states].frequency = CPUFREQ_TABLE_END;
835 
836 	max_boost_ratio = get_max_boost_ratio(cpu);
837 	if (max_boost_ratio) {
838 		unsigned int freq = freq_table[0].frequency;
839 
840 		/*
841 		 * Because the loop above sorts the freq_table entries in the
842 		 * descending order, freq is the maximum frequency in the table.
843 		 * Assume that it corresponds to the CPPC nominal frequency and
844 		 * use it to set cpuinfo.max_freq.
845 		 */
846 		policy->cpuinfo.max_freq = freq * max_boost_ratio >> SCHED_CAPACITY_SHIFT;
847 	} else {
848 		/*
849 		 * If the maximum "boost" frequency is unknown, ask the arch
850 		 * scale-invariance code to use the "nominal" performance for
851 		 * CPU utilization scaling so as to prevent the schedutil
852 		 * governor from selecting inadequate CPU frequencies.
853 		 */
854 		arch_set_max_freq_ratio(true);
855 	}
856 
857 	policy->freq_table = freq_table;
858 	perf->state = 0;
859 
860 	switch (perf->control_register.space_id) {
861 	case ACPI_ADR_SPACE_SYSTEM_IO:
862 		/*
863 		 * The core will not set policy->cur, because
864 		 * cpufreq_driver->get is NULL, so we need to set it here.
865 		 * However, we have to guess it, because the current speed is
866 		 * unknown and not detectable via IO ports.
867 		 */
868 		policy->cur = acpi_cpufreq_guess_freq(data, policy->cpu);
869 		break;
870 	case ACPI_ADR_SPACE_FIXED_HARDWARE:
871 		acpi_cpufreq_driver.get = get_cur_freq_on_cpu;
872 		break;
873 	default:
874 		break;
875 	}
876 
877 	/* notify BIOS that we exist */
878 	acpi_processor_notify_smm(THIS_MODULE);
879 
880 	pr_debug("CPU%u - ACPI performance management activated.\n", cpu);
881 	for (i = 0; i < perf->state_count; i++)
882 		pr_debug("     %cP%d: %d MHz, %d mW, %d uS\n",
883 			(i == perf->state ? '*' : ' '), i,
884 			(u32) perf->states[i].core_frequency,
885 			(u32) perf->states[i].power,
886 			(u32) perf->states[i].transition_latency);
887 
888 	/*
889 	 * the first call to ->target() should result in us actually
890 	 * writing something to the appropriate registers.
891 	 */
892 	data->resume = 1;
893 
894 	policy->fast_switch_possible = !acpi_pstate_strict &&
895 		!(policy_is_shared(policy) && policy->shared_type != CPUFREQ_SHARED_TYPE_ANY);
896 
897 	if (perf->states[0].core_frequency * 1000 != freq_table[0].frequency)
898 		pr_warn(FW_WARN "P-state 0 is not max freq\n");
899 
900 	return result;
901 
902 err_unreg:
903 	acpi_processor_unregister_performance(cpu);
904 err_free_mask:
905 	free_cpumask_var(data->freqdomain_cpus);
906 err_free:
907 	kfree(data);
908 	policy->driver_data = NULL;
909 
910 	return result;
911 }
912 
913 static int acpi_cpufreq_cpu_exit(struct cpufreq_policy *policy)
914 {
915 	struct acpi_cpufreq_data *data = policy->driver_data;
916 
917 	pr_debug("%s\n", __func__);
918 
919 	policy->fast_switch_possible = false;
920 	policy->driver_data = NULL;
921 	acpi_processor_unregister_performance(data->acpi_perf_cpu);
922 	free_cpumask_var(data->freqdomain_cpus);
923 	kfree(policy->freq_table);
924 	kfree(data);
925 
926 	return 0;
927 }
928 
929 static int acpi_cpufreq_resume(struct cpufreq_policy *policy)
930 {
931 	struct acpi_cpufreq_data *data = policy->driver_data;
932 
933 	pr_debug("%s\n", __func__);
934 
935 	data->resume = 1;
936 
937 	return 0;
938 }
939 
940 static struct freq_attr *acpi_cpufreq_attr[] = {
941 	&cpufreq_freq_attr_scaling_available_freqs,
942 	&freqdomain_cpus,
943 #ifdef CONFIG_X86_ACPI_CPUFREQ_CPB
944 	&cpb,
945 #endif
946 	NULL,
947 };
948 
949 static struct cpufreq_driver acpi_cpufreq_driver = {
950 	.verify		= cpufreq_generic_frequency_table_verify,
951 	.target_index	= acpi_cpufreq_target,
952 	.fast_switch	= acpi_cpufreq_fast_switch,
953 	.bios_limit	= acpi_processor_get_bios_limit,
954 	.init		= acpi_cpufreq_cpu_init,
955 	.exit		= acpi_cpufreq_cpu_exit,
956 	.resume		= acpi_cpufreq_resume,
957 	.name		= "acpi-cpufreq",
958 	.attr		= acpi_cpufreq_attr,
959 };
960 
961 static enum cpuhp_state acpi_cpufreq_online;
962 
963 static void __init acpi_cpufreq_boost_init(void)
964 {
965 	int ret;
966 
967 	if (!(boot_cpu_has(X86_FEATURE_CPB) || boot_cpu_has(X86_FEATURE_IDA))) {
968 		pr_debug("Boost capabilities not present in the processor\n");
969 		return;
970 	}
971 
972 	acpi_cpufreq_driver.set_boost = set_boost;
973 	acpi_cpufreq_driver.boost_enabled = boost_state(0);
974 
975 	/*
976 	 * This calls the online callback on all online cpu and forces all
977 	 * MSRs to the same value.
978 	 */
979 	ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "cpufreq/acpi:online",
980 				cpufreq_boost_online, cpufreq_boost_down_prep);
981 	if (ret < 0) {
982 		pr_err("acpi_cpufreq: failed to register hotplug callbacks\n");
983 		return;
984 	}
985 	acpi_cpufreq_online = ret;
986 }
987 
988 static void acpi_cpufreq_boost_exit(void)
989 {
990 	if (acpi_cpufreq_online > 0)
991 		cpuhp_remove_state_nocalls(acpi_cpufreq_online);
992 }
993 
994 static int __init acpi_cpufreq_init(void)
995 {
996 	int ret;
997 
998 	if (acpi_disabled)
999 		return -ENODEV;
1000 
1001 	/* don't keep reloading if cpufreq_driver exists */
1002 	if (cpufreq_get_current_driver())
1003 		return -EEXIST;
1004 
1005 	pr_debug("%s\n", __func__);
1006 
1007 	ret = acpi_cpufreq_early_init();
1008 	if (ret)
1009 		return ret;
1010 
1011 #ifdef CONFIG_X86_ACPI_CPUFREQ_CPB
1012 	/* this is a sysfs file with a strange name and an even stranger
1013 	 * semantic - per CPU instantiation, but system global effect.
1014 	 * Lets enable it only on AMD CPUs for compatibility reasons and
1015 	 * only if configured. This is considered legacy code, which
1016 	 * will probably be removed at some point in the future.
1017 	 */
1018 	if (!check_amd_hwpstate_cpu(0)) {
1019 		struct freq_attr **attr;
1020 
1021 		pr_debug("CPB unsupported, do not expose it\n");
1022 
1023 		for (attr = acpi_cpufreq_attr; *attr; attr++)
1024 			if (*attr == &cpb) {
1025 				*attr = NULL;
1026 				break;
1027 			}
1028 	}
1029 #endif
1030 	acpi_cpufreq_boost_init();
1031 
1032 	ret = cpufreq_register_driver(&acpi_cpufreq_driver);
1033 	if (ret) {
1034 		free_acpi_perf_data();
1035 		acpi_cpufreq_boost_exit();
1036 	}
1037 	return ret;
1038 }
1039 
1040 static void __exit acpi_cpufreq_exit(void)
1041 {
1042 	pr_debug("%s\n", __func__);
1043 
1044 	acpi_cpufreq_boost_exit();
1045 
1046 	cpufreq_unregister_driver(&acpi_cpufreq_driver);
1047 
1048 	free_acpi_perf_data();
1049 }
1050 
1051 module_param(acpi_pstate_strict, uint, 0644);
1052 MODULE_PARM_DESC(acpi_pstate_strict,
1053 	"value 0 or non-zero. non-zero -> strict ACPI checks are "
1054 	"performed during frequency changes.");
1055 
1056 late_initcall(acpi_cpufreq_init);
1057 module_exit(acpi_cpufreq_exit);
1058 
1059 static const struct x86_cpu_id __maybe_unused acpi_cpufreq_ids[] = {
1060 	X86_MATCH_FEATURE(X86_FEATURE_ACPI, NULL),
1061 	X86_MATCH_FEATURE(X86_FEATURE_HW_PSTATE, NULL),
1062 	{}
1063 };
1064 MODULE_DEVICE_TABLE(x86cpu, acpi_cpufreq_ids);
1065 
1066 static const struct acpi_device_id __maybe_unused processor_device_ids[] = {
1067 	{ACPI_PROCESSOR_OBJECT_HID, },
1068 	{ACPI_PROCESSOR_DEVICE_HID, },
1069 	{},
1070 };
1071 MODULE_DEVICE_TABLE(acpi, processor_device_ids);
1072 
1073 MODULE_ALIAS("acpi");
1074