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1/*
2 * CPPC (Collaborative Processor Performance Control) driver for
3 * interfacing with the CPUfreq layer and governors. See
4 * cppc_acpi.c for CPPC specific methods.
5 *
6 * (C) Copyright 2014, 2015 Linaro Ltd.
7 * Author: Ashwin Chaugule <ashwin.chaugule@linaro.org>
8 *
9 * This program is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU General Public License
11 * as published by the Free Software Foundation; version 2
12 * of the License.
13 */
14
15#define pr_fmt(fmt) "CPPC Cpufreq:" fmt
16
17#include <linux/kernel.h>
18#include <linux/module.h>
19#include <linux/delay.h>
20#include <linux/cpu.h>
21#include <linux/cpufreq.h>
ad38677d 22#include <linux/dmi.h>
3d41386d 23#include <linux/time.h>
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24#include <linux/vmalloc.h>
25
ad38677d
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26#include <asm/unaligned.h>
27
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28#include <acpi/cppc_acpi.h>
29
ad38677d
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30/* Minimum struct length needed for the DMI processor entry we want */
31#define DMI_ENTRY_PROCESSOR_MIN_LENGTH 48
32
33/* Offest in the DMI processor structure for the max frequency */
34#define DMI_PROCESSOR_MAX_SPEED 0x14
35
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36/*
37 * These structs contain information parsed from per CPU
38 * ACPI _CPC structures.
39 * e.g. For each CPU the highest, lowest supported
40 * performance capabilities, desired performance level
41 * requested etc.
42 */
41dd6403 43static struct cppc_cpudata **all_cpu_data;
5477fb3b 44
ad38677d
AS
45/* Callback function used to retrieve the max frequency from DMI */
46static void cppc_find_dmi_mhz(const struct dmi_header *dm, void *private)
47{
48 const u8 *dmi_data = (const u8 *)dm;
49 u16 *mhz = (u16 *)private;
50
51 if (dm->type == DMI_ENTRY_PROCESSOR &&
52 dm->length >= DMI_ENTRY_PROCESSOR_MIN_LENGTH) {
53 u16 val = (u16)get_unaligned((const u16 *)
54 (dmi_data + DMI_PROCESSOR_MAX_SPEED));
55 *mhz = val > *mhz ? val : *mhz;
56 }
57}
58
59/* Look up the max frequency in DMI */
60static u64 cppc_get_dmi_max_khz(void)
61{
62 u16 mhz = 0;
63
64 dmi_walk(cppc_find_dmi_mhz, &mhz);
65
66 /*
67 * Real stupid fallback value, just in case there is no
68 * actual value set.
69 */
70 mhz = mhz ? mhz : 1;
71
72 return (1000 * mhz);
73}
74
256f19d2
PP
75/*
76 * If CPPC lowest_freq and nominal_freq registers are exposed then we can
77 * use them to convert perf to freq and vice versa
78 *
79 * If the perf/freq point lies between Nominal and Lowest, we can treat
80 * (Low perf, Low freq) and (Nom Perf, Nom freq) as 2D co-ordinates of a line
81 * and extrapolate the rest
82 * For perf/freq > Nominal, we use the ratio perf:freq at Nominal for conversion
83 */
84static unsigned int cppc_cpufreq_perf_to_khz(struct cppc_cpudata *cpu,
85 unsigned int perf)
86{
87 static u64 max_khz;
88 struct cppc_perf_caps *caps = &cpu->perf_caps;
89 u64 mul, div;
90
91 if (caps->lowest_freq && caps->nominal_freq) {
92 if (perf >= caps->nominal_perf) {
93 mul = caps->nominal_freq;
94 div = caps->nominal_perf;
95 } else {
96 mul = caps->nominal_freq - caps->lowest_freq;
97 div = caps->nominal_perf - caps->lowest_perf;
98 }
99 } else {
100 if (!max_khz)
101 max_khz = cppc_get_dmi_max_khz();
102 mul = max_khz;
103 div = cpu->perf_caps.highest_perf;
104 }
105 return (u64)perf * mul / div;
106}
107
108static unsigned int cppc_cpufreq_khz_to_perf(struct cppc_cpudata *cpu,
109 unsigned int freq)
110{
111 static u64 max_khz;
112 struct cppc_perf_caps *caps = &cpu->perf_caps;
113 u64 mul, div;
114
115 if (caps->lowest_freq && caps->nominal_freq) {
116 if (freq >= caps->nominal_freq) {
117 mul = caps->nominal_perf;
118 div = caps->nominal_freq;
119 } else {
120 mul = caps->lowest_perf;
121 div = caps->lowest_freq;
122 }
123 } else {
124 if (!max_khz)
125 max_khz = cppc_get_dmi_max_khz();
126 mul = cpu->perf_caps.highest_perf;
127 div = max_khz;
128 }
129
130 return (u64)freq * mul / div;
131}
132
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133static int cppc_cpufreq_set_target(struct cpufreq_policy *policy,
134 unsigned int target_freq,
135 unsigned int relation)
136{
41dd6403 137 struct cppc_cpudata *cpu;
5477fb3b 138 struct cpufreq_freqs freqs;
c197d758 139 u32 desired_perf;
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140 int ret = 0;
141
142 cpu = all_cpu_data[policy->cpu];
143
256f19d2 144 desired_perf = cppc_cpufreq_khz_to_perf(cpu, target_freq);
c197d758
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145 /* Return if it is exactly the same perf */
146 if (desired_perf == cpu->perf_ctrls.desired_perf)
147 return ret;
148
149 cpu->perf_ctrls.desired_perf = desired_perf;
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150 freqs.old = policy->cur;
151 freqs.new = target_freq;
152
153 cpufreq_freq_transition_begin(policy, &freqs);
154 ret = cppc_set_perf(cpu->cpu, &cpu->perf_ctrls);
155 cpufreq_freq_transition_end(policy, &freqs, ret != 0);
156
157 if (ret)
158 pr_debug("Failed to set target on CPU:%d. ret:%d\n",
159 cpu->cpu, ret);
160
161 return ret;
162}
163
164static int cppc_verify_policy(struct cpufreq_policy *policy)
165{
166 cpufreq_verify_within_cpu_limits(policy);
167 return 0;
168}
169
170static void cppc_cpufreq_stop_cpu(struct cpufreq_policy *policy)
171{
172 int cpu_num = policy->cpu;
41dd6403 173 struct cppc_cpudata *cpu = all_cpu_data[cpu_num];
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174 int ret;
175
176 cpu->perf_ctrls.desired_perf = cpu->perf_caps.lowest_perf;
177
178 ret = cppc_set_perf(cpu_num, &cpu->perf_ctrls);
179 if (ret)
180 pr_debug("Err setting perf value:%d on CPU:%d. ret:%d\n",
181 cpu->perf_caps.lowest_perf, cpu_num, ret);
182}
183
d4f3388a
PP
184/*
185 * The PCC subspace describes the rate at which platform can accept commands
186 * on the shared PCC channel (including READs which do not count towards freq
187 * trasition requests), so ideally we need to use the PCC values as a fallback
188 * if we don't have a platform specific transition_delay_us
189 */
190#ifdef CONFIG_ARM64
191#include <asm/cputype.h>
192
193static unsigned int cppc_cpufreq_get_transition_delay_us(int cpu)
194{
195 unsigned long implementor = read_cpuid_implementor();
196 unsigned long part_num = read_cpuid_part_number();
197 unsigned int delay_us = 0;
198
199 switch (implementor) {
200 case ARM_CPU_IMP_QCOM:
201 switch (part_num) {
202 case QCOM_CPU_PART_FALKOR_V1:
203 case QCOM_CPU_PART_FALKOR:
204 delay_us = 10000;
205 break;
206 default:
207 delay_us = cppc_get_transition_latency(cpu) / NSEC_PER_USEC;
208 break;
209 }
210 break;
211 default:
212 delay_us = cppc_get_transition_latency(cpu) / NSEC_PER_USEC;
213 break;
214 }
215
216 return delay_us;
217}
218
219#else
220
221static unsigned int cppc_cpufreq_get_transition_delay_us(int cpu)
222{
223 return cppc_get_transition_latency(cpu) / NSEC_PER_USEC;
224}
225#endif
226
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227static int cppc_cpufreq_cpu_init(struct cpufreq_policy *policy)
228{
41dd6403 229 struct cppc_cpudata *cpu;
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230 unsigned int cpu_num = policy->cpu;
231 int ret = 0;
232
233 cpu = all_cpu_data[policy->cpu];
234
235 cpu->cpu = cpu_num;
236 ret = cppc_get_perf_caps(policy->cpu, &cpu->perf_caps);
237
238 if (ret) {
239 pr_debug("Err reading CPU%d perf capabilities. ret:%d\n",
240 cpu_num, ret);
241 return ret;
242 }
243
256f19d2
PP
244 /* Convert the lowest and nominal freq from MHz to KHz */
245 cpu->perf_caps.lowest_freq *= 1000;
246 cpu->perf_caps.nominal_freq *= 1000;
ad38677d 247
73808d0f
PP
248 /*
249 * Set min to lowest nonlinear perf to avoid any efficiency penalty (see
250 * Section 8.4.7.1.1.5 of ACPI 6.1 spec)
251 */
256f19d2
PP
252 policy->min = cppc_cpufreq_perf_to_khz(cpu, cpu->perf_caps.lowest_nonlinear_perf);
253 policy->max = cppc_cpufreq_perf_to_khz(cpu, cpu->perf_caps.highest_perf);
73808d0f
PP
254
255 /*
256 * Set cpuinfo.min_freq to Lowest to make the full range of performance
257 * available if userspace wants to use any perf between lowest & lowest
258 * nonlinear perf
259 */
256f19d2
PP
260 policy->cpuinfo.min_freq = cppc_cpufreq_perf_to_khz(cpu, cpu->perf_caps.lowest_perf);
261 policy->cpuinfo.max_freq = cppc_cpufreq_perf_to_khz(cpu, cpu->perf_caps.highest_perf);
73808d0f 262
d4f3388a 263 policy->transition_delay_us = cppc_cpufreq_get_transition_delay_us(cpu_num);
9dc17917 264 policy->shared_type = cpu->shared_type;
5477fb3b 265
8913315e
SY
266 if (policy->shared_type == CPUFREQ_SHARED_TYPE_ANY) {
267 int i;
268
5477fb3b 269 cpumask_copy(policy->cpus, cpu->shared_cpu_map);
8913315e
SY
270
271 for_each_cpu(i, policy->cpus) {
272 if (unlikely(i == policy->cpu))
273 continue;
274
275 memcpy(&all_cpu_data[i]->perf_caps, &cpu->perf_caps,
276 sizeof(cpu->perf_caps));
277 }
278 } else if (policy->shared_type == CPUFREQ_SHARED_TYPE_ALL) {
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279 /* Support only SW_ANY for now. */
280 pr_debug("Unsupported CPU co-ord type\n");
281 return -EFAULT;
282 }
283
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284 cpu->cur_policy = policy;
285
286 /* Set policy->cur to max now. The governors will adjust later. */
256f19d2
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287 policy->cur = cppc_cpufreq_perf_to_khz(cpu,
288 cpu->perf_caps.highest_perf);
ad38677d 289 cpu->perf_ctrls.desired_perf = cpu->perf_caps.highest_perf;
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290
291 ret = cppc_set_perf(cpu_num, &cpu->perf_ctrls);
292 if (ret)
293 pr_debug("Err setting perf value:%d on CPU:%d. ret:%d\n",
294 cpu->perf_caps.highest_perf, cpu_num, ret);
295
296 return ret;
297}
298
299static struct cpufreq_driver cppc_cpufreq_driver = {
300 .flags = CPUFREQ_CONST_LOOPS,
301 .verify = cppc_verify_policy,
302 .target = cppc_cpufreq_set_target,
303 .init = cppc_cpufreq_cpu_init,
304 .stop_cpu = cppc_cpufreq_stop_cpu,
305 .name = "cppc_cpufreq",
306};
307
308static int __init cppc_cpufreq_init(void)
309{
310 int i, ret = 0;
41dd6403 311 struct cppc_cpudata *cpu;
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312
313 if (acpi_disabled)
314 return -ENODEV;
315
6396bb22
KC
316 all_cpu_data = kcalloc(num_possible_cpus(), sizeof(void *),
317 GFP_KERNEL);
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318 if (!all_cpu_data)
319 return -ENOMEM;
320
321 for_each_possible_cpu(i) {
41dd6403 322 all_cpu_data[i] = kzalloc(sizeof(struct cppc_cpudata), GFP_KERNEL);
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323 if (!all_cpu_data[i])
324 goto out;
325
326 cpu = all_cpu_data[i];
327 if (!zalloc_cpumask_var(&cpu->shared_cpu_map, GFP_KERNEL))
328 goto out;
329 }
330
331 ret = acpi_get_psd_map(all_cpu_data);
332 if (ret) {
333 pr_debug("Error parsing PSD data. Aborting cpufreq registration.\n");
334 goto out;
335 }
336
337 ret = cpufreq_register_driver(&cppc_cpufreq_driver);
338 if (ret)
339 goto out;
340
341 return ret;
342
343out:
55b55abc
CH
344 for_each_possible_cpu(i) {
345 cpu = all_cpu_data[i];
346 if (!cpu)
347 break;
348 free_cpumask_var(cpu->shared_cpu_map);
349 kfree(cpu);
350 }
5477fb3b
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351
352 kfree(all_cpu_data);
353 return -ENODEV;
354}
355
a29a1e76
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356static void __exit cppc_cpufreq_exit(void)
357{
41dd6403 358 struct cppc_cpudata *cpu;
a29a1e76
AC
359 int i;
360
361 cpufreq_unregister_driver(&cppc_cpufreq_driver);
362
363 for_each_possible_cpu(i) {
364 cpu = all_cpu_data[i];
365 free_cpumask_var(cpu->shared_cpu_map);
366 kfree(cpu);
367 }
368
369 kfree(all_cpu_data);
370}
371
372module_exit(cppc_cpufreq_exit);
373MODULE_AUTHOR("Ashwin Chaugule");
374MODULE_DESCRIPTION("CPUFreq driver based on the ACPI CPPC v5.0+ spec");
375MODULE_LICENSE("GPL");
376
5477fb3b 377late_initcall(cppc_cpufreq_init);
974f8649
PP
378
379static const struct acpi_device_id cppc_acpi_ids[] = {
380 {ACPI_PROCESSOR_DEVICE_HID, },
381 {}
382};
383
384MODULE_DEVICE_TABLE(acpi, cppc_acpi_ids);