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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * CPPC (Collaborative Processor Performance Control) driver for
4 * interfacing with the CPUfreq layer and governors. See
5 * cppc_acpi.c for CPPC specific methods.
6 *
7 * (C) Copyright 2014, 2015 Linaro Ltd.
8 * Author: Ashwin Chaugule <ashwin.chaugule@linaro.org>
9 */
10
11#define pr_fmt(fmt) "CPPC Cpufreq:" fmt
12
13#include <linux/kernel.h>
14#include <linux/module.h>
15#include <linux/delay.h>
16#include <linux/cpu.h>
17#include <linux/cpufreq.h>
18#include <linux/dmi.h>
19#include <linux/time.h>
20#include <linux/vmalloc.h>
21
22#include <asm/unaligned.h>
23
24#include <acpi/cppc_acpi.h>
25
26/* Minimum struct length needed for the DMI processor entry we want */
27#define DMI_ENTRY_PROCESSOR_MIN_LENGTH 48
28
29/* Offest in the DMI processor structure for the max frequency */
30#define DMI_PROCESSOR_MAX_SPEED 0x14
31
32/*
33 * These structs contain information parsed from per CPU
34 * ACPI _CPC structures.
35 * e.g. For each CPU the highest, lowest supported
36 * performance capabilities, desired performance level
37 * requested etc.
38 */
39static struct cppc_cpudata **all_cpu_data;
40static bool boost_supported;
41
42struct cppc_workaround_oem_info {
43 char oem_id[ACPI_OEM_ID_SIZE + 1];
44 char oem_table_id[ACPI_OEM_TABLE_ID_SIZE + 1];
45 u32 oem_revision;
46};
47
48static struct cppc_workaround_oem_info wa_info[] = {
49 {
50 .oem_id = "HISI ",
51 .oem_table_id = "HIP07 ",
52 .oem_revision = 0,
53 }, {
54 .oem_id = "HISI ",
55 .oem_table_id = "HIP08 ",
56 .oem_revision = 0,
57 }
58};
59
60/* Callback function used to retrieve the max frequency from DMI */
61static void cppc_find_dmi_mhz(const struct dmi_header *dm, void *private)
62{
63 const u8 *dmi_data = (const u8 *)dm;
64 u16 *mhz = (u16 *)private;
65
66 if (dm->type == DMI_ENTRY_PROCESSOR &&
67 dm->length >= DMI_ENTRY_PROCESSOR_MIN_LENGTH) {
68 u16 val = (u16)get_unaligned((const u16 *)
69 (dmi_data + DMI_PROCESSOR_MAX_SPEED));
70 *mhz = val > *mhz ? val : *mhz;
71 }
72}
73
74/* Look up the max frequency in DMI */
75static u64 cppc_get_dmi_max_khz(void)
76{
77 u16 mhz = 0;
78
79 dmi_walk(cppc_find_dmi_mhz, &mhz);
80
81 /*
82 * Real stupid fallback value, just in case there is no
83 * actual value set.
84 */
85 mhz = mhz ? mhz : 1;
86
87 return (1000 * mhz);
88}
89
90/*
91 * If CPPC lowest_freq and nominal_freq registers are exposed then we can
92 * use them to convert perf to freq and vice versa
93 *
94 * If the perf/freq point lies between Nominal and Lowest, we can treat
95 * (Low perf, Low freq) and (Nom Perf, Nom freq) as 2D co-ordinates of a line
96 * and extrapolate the rest
97 * For perf/freq > Nominal, we use the ratio perf:freq at Nominal for conversion
98 */
99static unsigned int cppc_cpufreq_perf_to_khz(struct cppc_cpudata *cpu,
100 unsigned int perf)
101{
102 static u64 max_khz;
103 struct cppc_perf_caps *caps = &cpu->perf_caps;
104 u64 mul, div;
105
106 if (caps->lowest_freq && caps->nominal_freq) {
107 if (perf >= caps->nominal_perf) {
108 mul = caps->nominal_freq;
109 div = caps->nominal_perf;
110 } else {
111 mul = caps->nominal_freq - caps->lowest_freq;
112 div = caps->nominal_perf - caps->lowest_perf;
113 }
114 } else {
115 if (!max_khz)
116 max_khz = cppc_get_dmi_max_khz();
117 mul = max_khz;
118 div = caps->highest_perf;
119 }
120 return (u64)perf * mul / div;
121}
122
123static unsigned int cppc_cpufreq_khz_to_perf(struct cppc_cpudata *cpu,
124 unsigned int freq)
125{
126 static u64 max_khz;
127 struct cppc_perf_caps *caps = &cpu->perf_caps;
128 u64 mul, div;
129
130 if (caps->lowest_freq && caps->nominal_freq) {
131 if (freq >= caps->nominal_freq) {
132 mul = caps->nominal_perf;
133 div = caps->nominal_freq;
134 } else {
135 mul = caps->lowest_perf;
136 div = caps->lowest_freq;
137 }
138 } else {
139 if (!max_khz)
140 max_khz = cppc_get_dmi_max_khz();
141 mul = caps->highest_perf;
142 div = max_khz;
143 }
144
145 return (u64)freq * mul / div;
146}
147
148static int cppc_cpufreq_set_target(struct cpufreq_policy *policy,
149 unsigned int target_freq,
150 unsigned int relation)
151{
152 struct cppc_cpudata *cpu;
153 struct cpufreq_freqs freqs;
154 u32 desired_perf;
155 int ret = 0;
156
157 cpu = all_cpu_data[policy->cpu];
158
159 desired_perf = cppc_cpufreq_khz_to_perf(cpu, target_freq);
160 /* Return if it is exactly the same perf */
161 if (desired_perf == cpu->perf_ctrls.desired_perf)
162 return ret;
163
164 cpu->perf_ctrls.desired_perf = desired_perf;
165 freqs.old = policy->cur;
166 freqs.new = target_freq;
167
168 cpufreq_freq_transition_begin(policy, &freqs);
169 ret = cppc_set_perf(cpu->cpu, &cpu->perf_ctrls);
170 cpufreq_freq_transition_end(policy, &freqs, ret != 0);
171
172 if (ret)
173 pr_debug("Failed to set target on CPU:%d. ret:%d\n",
174 cpu->cpu, ret);
175
176 return ret;
177}
178
179static int cppc_verify_policy(struct cpufreq_policy_data *policy)
180{
181 cpufreq_verify_within_cpu_limits(policy);
182 return 0;
183}
184
185static void cppc_cpufreq_stop_cpu(struct cpufreq_policy *policy)
186{
187 int cpu_num = policy->cpu;
188 struct cppc_cpudata *cpu = all_cpu_data[cpu_num];
189 int ret;
190
191 cpu->perf_ctrls.desired_perf = cpu->perf_caps.lowest_perf;
192
193 ret = cppc_set_perf(cpu_num, &cpu->perf_ctrls);
194 if (ret)
195 pr_debug("Err setting perf value:%d on CPU:%d. ret:%d\n",
196 cpu->perf_caps.lowest_perf, cpu_num, ret);
197}
198
199/*
200 * The PCC subspace describes the rate at which platform can accept commands
201 * on the shared PCC channel (including READs which do not count towards freq
202 * trasition requests), so ideally we need to use the PCC values as a fallback
203 * if we don't have a platform specific transition_delay_us
204 */
205#ifdef CONFIG_ARM64
206#include <asm/cputype.h>
207
208static unsigned int cppc_cpufreq_get_transition_delay_us(int cpu)
209{
210 unsigned long implementor = read_cpuid_implementor();
211 unsigned long part_num = read_cpuid_part_number();
212 unsigned int delay_us = 0;
213
214 switch (implementor) {
215 case ARM_CPU_IMP_QCOM:
216 switch (part_num) {
217 case QCOM_CPU_PART_FALKOR_V1:
218 case QCOM_CPU_PART_FALKOR:
219 delay_us = 10000;
220 break;
221 default:
222 delay_us = cppc_get_transition_latency(cpu) / NSEC_PER_USEC;
223 break;
224 }
225 break;
226 default:
227 delay_us = cppc_get_transition_latency(cpu) / NSEC_PER_USEC;
228 break;
229 }
230
231 return delay_us;
232}
233
234#else
235
236static unsigned int cppc_cpufreq_get_transition_delay_us(int cpu)
237{
238 return cppc_get_transition_latency(cpu) / NSEC_PER_USEC;
239}
240#endif
241
242static int cppc_cpufreq_cpu_init(struct cpufreq_policy *policy)
243{
244 struct cppc_cpudata *cpu;
245 unsigned int cpu_num = policy->cpu;
246 int ret = 0;
247
248 cpu = all_cpu_data[policy->cpu];
249
250 cpu->cpu = cpu_num;
251 ret = cppc_get_perf_caps(policy->cpu, &cpu->perf_caps);
252
253 if (ret) {
254 pr_debug("Err reading CPU%d perf capabilities. ret:%d\n",
255 cpu_num, ret);
256 return ret;
257 }
258
259 /* Convert the lowest and nominal freq from MHz to KHz */
260 cpu->perf_caps.lowest_freq *= 1000;
261 cpu->perf_caps.nominal_freq *= 1000;
262
263 /*
264 * Set min to lowest nonlinear perf to avoid any efficiency penalty (see
265 * Section 8.4.7.1.1.5 of ACPI 6.1 spec)
266 */
267 policy->min = cppc_cpufreq_perf_to_khz(cpu, cpu->perf_caps.lowest_nonlinear_perf);
268 policy->max = cppc_cpufreq_perf_to_khz(cpu, cpu->perf_caps.nominal_perf);
269
270 /*
271 * Set cpuinfo.min_freq to Lowest to make the full range of performance
272 * available if userspace wants to use any perf between lowest & lowest
273 * nonlinear perf
274 */
275 policy->cpuinfo.min_freq = cppc_cpufreq_perf_to_khz(cpu, cpu->perf_caps.lowest_perf);
276 policy->cpuinfo.max_freq = cppc_cpufreq_perf_to_khz(cpu, cpu->perf_caps.nominal_perf);
277
278 policy->transition_delay_us = cppc_cpufreq_get_transition_delay_us(cpu_num);
279 policy->shared_type = cpu->shared_type;
280
281 if (policy->shared_type == CPUFREQ_SHARED_TYPE_ANY) {
282 int i;
283
284 cpumask_copy(policy->cpus, cpu->shared_cpu_map);
285
286 for_each_cpu(i, policy->cpus) {
287 if (unlikely(i == policy->cpu))
288 continue;
289
290 memcpy(&all_cpu_data[i]->perf_caps, &cpu->perf_caps,
291 sizeof(cpu->perf_caps));
292 }
293 } else if (policy->shared_type == CPUFREQ_SHARED_TYPE_ALL) {
294 /* Support only SW_ANY for now. */
295 pr_debug("Unsupported CPU co-ord type\n");
296 return -EFAULT;
297 }
298
299 cpu->cur_policy = policy;
300
301 /*
302 * If 'highest_perf' is greater than 'nominal_perf', we assume CPU Boost
303 * is supported.
304 */
305 if (cpu->perf_caps.highest_perf > cpu->perf_caps.nominal_perf)
306 boost_supported = true;
307
308 /* Set policy->cur to max now. The governors will adjust later. */
309 policy->cur = cppc_cpufreq_perf_to_khz(cpu,
310 cpu->perf_caps.highest_perf);
311 cpu->perf_ctrls.desired_perf = cpu->perf_caps.highest_perf;
312
313 ret = cppc_set_perf(cpu_num, &cpu->perf_ctrls);
314 if (ret)
315 pr_debug("Err setting perf value:%d on CPU:%d. ret:%d\n",
316 cpu->perf_caps.highest_perf, cpu_num, ret);
317
318 return ret;
319}
320
321static inline u64 get_delta(u64 t1, u64 t0)
322{
323 if (t1 > t0 || t0 > ~(u32)0)
324 return t1 - t0;
325
326 return (u32)t1 - (u32)t0;
327}
328
329static int cppc_get_rate_from_fbctrs(struct cppc_cpudata *cpu,
330 struct cppc_perf_fb_ctrs fb_ctrs_t0,
331 struct cppc_perf_fb_ctrs fb_ctrs_t1)
332{
333 u64 delta_reference, delta_delivered;
334 u64 reference_perf, delivered_perf;
335
336 reference_perf = fb_ctrs_t0.reference_perf;
337
338 delta_reference = get_delta(fb_ctrs_t1.reference,
339 fb_ctrs_t0.reference);
340 delta_delivered = get_delta(fb_ctrs_t1.delivered,
341 fb_ctrs_t0.delivered);
342
343 /* Check to avoid divide-by zero */
344 if (delta_reference || delta_delivered)
345 delivered_perf = (reference_perf * delta_delivered) /
346 delta_reference;
347 else
348 delivered_perf = cpu->perf_ctrls.desired_perf;
349
350 return cppc_cpufreq_perf_to_khz(cpu, delivered_perf);
351}
352
353static unsigned int cppc_cpufreq_get_rate(unsigned int cpunum)
354{
355 struct cppc_perf_fb_ctrs fb_ctrs_t0 = {0}, fb_ctrs_t1 = {0};
356 struct cppc_cpudata *cpu = all_cpu_data[cpunum];
357 int ret;
358
359 ret = cppc_get_perf_ctrs(cpunum, &fb_ctrs_t0);
360 if (ret)
361 return ret;
362
363 udelay(2); /* 2usec delay between sampling */
364
365 ret = cppc_get_perf_ctrs(cpunum, &fb_ctrs_t1);
366 if (ret)
367 return ret;
368
369 return cppc_get_rate_from_fbctrs(cpu, fb_ctrs_t0, fb_ctrs_t1);
370}
371
372static int cppc_cpufreq_set_boost(struct cpufreq_policy *policy, int state)
373{
374 struct cppc_cpudata *cpudata;
375 int ret;
376
377 if (!boost_supported) {
378 pr_err("BOOST not supported by CPU or firmware\n");
379 return -EINVAL;
380 }
381
382 cpudata = all_cpu_data[policy->cpu];
383 if (state)
384 policy->max = cppc_cpufreq_perf_to_khz(cpudata,
385 cpudata->perf_caps.highest_perf);
386 else
387 policy->max = cppc_cpufreq_perf_to_khz(cpudata,
388 cpudata->perf_caps.nominal_perf);
389 policy->cpuinfo.max_freq = policy->max;
390
391 ret = freq_qos_update_request(policy->max_freq_req, policy->max);
392 if (ret < 0)
393 return ret;
394
395 return 0;
396}
397
398static struct cpufreq_driver cppc_cpufreq_driver = {
399 .flags = CPUFREQ_CONST_LOOPS,
400 .verify = cppc_verify_policy,
401 .target = cppc_cpufreq_set_target,
402 .get = cppc_cpufreq_get_rate,
403 .init = cppc_cpufreq_cpu_init,
404 .stop_cpu = cppc_cpufreq_stop_cpu,
405 .set_boost = cppc_cpufreq_set_boost,
406 .name = "cppc_cpufreq",
407};
408
409/*
410 * HISI platform does not support delivered performance counter and
411 * reference performance counter. It can calculate the performance using the
412 * platform specific mechanism. We reuse the desired performance register to
413 * store the real performance calculated by the platform.
414 */
415static unsigned int hisi_cppc_cpufreq_get_rate(unsigned int cpunum)
416{
417 struct cppc_cpudata *cpudata = all_cpu_data[cpunum];
418 u64 desired_perf;
419 int ret;
420
421 ret = cppc_get_desired_perf(cpunum, &desired_perf);
422 if (ret < 0)
423 return -EIO;
424
425 return cppc_cpufreq_perf_to_khz(cpudata, desired_perf);
426}
427
428static void cppc_check_hisi_workaround(void)
429{
430 struct acpi_table_header *tbl;
431 acpi_status status = AE_OK;
432 int i;
433
434 status = acpi_get_table(ACPI_SIG_PCCT, 0, &tbl);
435 if (ACPI_FAILURE(status) || !tbl)
436 return;
437
438 for (i = 0; i < ARRAY_SIZE(wa_info); i++) {
439 if (!memcmp(wa_info[i].oem_id, tbl->oem_id, ACPI_OEM_ID_SIZE) &&
440 !memcmp(wa_info[i].oem_table_id, tbl->oem_table_id, ACPI_OEM_TABLE_ID_SIZE) &&
441 wa_info[i].oem_revision == tbl->oem_revision) {
442 /* Overwrite the get() callback */
443 cppc_cpufreq_driver.get = hisi_cppc_cpufreq_get_rate;
444 break;
445 }
446 }
447
448 acpi_put_table(tbl);
449}
450
451static int __init cppc_cpufreq_init(void)
452{
453 int i, ret = 0;
454 struct cppc_cpudata *cpu;
455
456 if (acpi_disabled)
457 return -ENODEV;
458
459 all_cpu_data = kcalloc(num_possible_cpus(), sizeof(void *),
460 GFP_KERNEL);
461 if (!all_cpu_data)
462 return -ENOMEM;
463
464 for_each_possible_cpu(i) {
465 all_cpu_data[i] = kzalloc(sizeof(struct cppc_cpudata), GFP_KERNEL);
466 if (!all_cpu_data[i])
467 goto out;
468
469 cpu = all_cpu_data[i];
470 if (!zalloc_cpumask_var(&cpu->shared_cpu_map, GFP_KERNEL))
471 goto out;
472 }
473
474 ret = acpi_get_psd_map(all_cpu_data);
475 if (ret) {
476 pr_debug("Error parsing PSD data. Aborting cpufreq registration.\n");
477 goto out;
478 }
479
480 cppc_check_hisi_workaround();
481
482 ret = cpufreq_register_driver(&cppc_cpufreq_driver);
483 if (ret)
484 goto out;
485
486 return ret;
487
488out:
489 for_each_possible_cpu(i) {
490 cpu = all_cpu_data[i];
491 if (!cpu)
492 break;
493 free_cpumask_var(cpu->shared_cpu_map);
494 kfree(cpu);
495 }
496
497 kfree(all_cpu_data);
498 return -ENODEV;
499}
500
501static void __exit cppc_cpufreq_exit(void)
502{
503 struct cppc_cpudata *cpu;
504 int i;
505
506 cpufreq_unregister_driver(&cppc_cpufreq_driver);
507
508 for_each_possible_cpu(i) {
509 cpu = all_cpu_data[i];
510 free_cpumask_var(cpu->shared_cpu_map);
511 kfree(cpu);
512 }
513
514 kfree(all_cpu_data);
515}
516
517module_exit(cppc_cpufreq_exit);
518MODULE_AUTHOR("Ashwin Chaugule");
519MODULE_DESCRIPTION("CPUFreq driver based on the ACPI CPPC v5.0+ spec");
520MODULE_LICENSE("GPL");
521
522late_initcall(cppc_cpufreq_init);
523
524static const struct acpi_device_id cppc_acpi_ids[] __used = {
525 {ACPI_PROCESSOR_DEVICE_HID, },
526 {}
527};
528
529MODULE_DEVICE_TABLE(acpi, cppc_acpi_ids);