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5477fb3b AC |
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> |
5477fb3b AC |
23 | #include <linux/vmalloc.h> |
24 | ||
ad38677d AS |
25 | #include <asm/unaligned.h> |
26 | ||
5477fb3b AC |
27 | #include <acpi/cppc_acpi.h> |
28 | ||
ad38677d AS |
29 | /* Minimum struct length needed for the DMI processor entry we want */ |
30 | #define DMI_ENTRY_PROCESSOR_MIN_LENGTH 48 | |
31 | ||
32 | /* Offest in the DMI processor structure for the max frequency */ | |
33 | #define DMI_PROCESSOR_MAX_SPEED 0x14 | |
34 | ||
5477fb3b AC |
35 | /* |
36 | * These structs contain information parsed from per CPU | |
37 | * ACPI _CPC structures. | |
38 | * e.g. For each CPU the highest, lowest supported | |
39 | * performance capabilities, desired performance level | |
40 | * requested etc. | |
41 | */ | |
41dd6403 | 42 | static struct cppc_cpudata **all_cpu_data; |
5477fb3b | 43 | |
ad38677d AS |
44 | /* Capture the max KHz from DMI */ |
45 | static u64 cppc_dmi_max_khz; | |
46 | ||
47 | /* Callback function used to retrieve the max frequency from DMI */ | |
48 | static void cppc_find_dmi_mhz(const struct dmi_header *dm, void *private) | |
49 | { | |
50 | const u8 *dmi_data = (const u8 *)dm; | |
51 | u16 *mhz = (u16 *)private; | |
52 | ||
53 | if (dm->type == DMI_ENTRY_PROCESSOR && | |
54 | dm->length >= DMI_ENTRY_PROCESSOR_MIN_LENGTH) { | |
55 | u16 val = (u16)get_unaligned((const u16 *) | |
56 | (dmi_data + DMI_PROCESSOR_MAX_SPEED)); | |
57 | *mhz = val > *mhz ? val : *mhz; | |
58 | } | |
59 | } | |
60 | ||
61 | /* Look up the max frequency in DMI */ | |
62 | static u64 cppc_get_dmi_max_khz(void) | |
63 | { | |
64 | u16 mhz = 0; | |
65 | ||
66 | dmi_walk(cppc_find_dmi_mhz, &mhz); | |
67 | ||
68 | /* | |
69 | * Real stupid fallback value, just in case there is no | |
70 | * actual value set. | |
71 | */ | |
72 | mhz = mhz ? mhz : 1; | |
73 | ||
74 | return (1000 * mhz); | |
75 | } | |
76 | ||
5477fb3b AC |
77 | static int cppc_cpufreq_set_target(struct cpufreq_policy *policy, |
78 | unsigned int target_freq, | |
79 | unsigned int relation) | |
80 | { | |
41dd6403 | 81 | struct cppc_cpudata *cpu; |
5477fb3b | 82 | struct cpufreq_freqs freqs; |
c197d758 | 83 | u32 desired_perf; |
5477fb3b AC |
84 | int ret = 0; |
85 | ||
86 | cpu = all_cpu_data[policy->cpu]; | |
87 | ||
c197d758 HT |
88 | desired_perf = (u64)target_freq * cpu->perf_caps.highest_perf / cppc_dmi_max_khz; |
89 | /* Return if it is exactly the same perf */ | |
90 | if (desired_perf == cpu->perf_ctrls.desired_perf) | |
91 | return ret; | |
92 | ||
93 | cpu->perf_ctrls.desired_perf = desired_perf; | |
5477fb3b AC |
94 | freqs.old = policy->cur; |
95 | freqs.new = target_freq; | |
96 | ||
97 | cpufreq_freq_transition_begin(policy, &freqs); | |
98 | ret = cppc_set_perf(cpu->cpu, &cpu->perf_ctrls); | |
99 | cpufreq_freq_transition_end(policy, &freqs, ret != 0); | |
100 | ||
101 | if (ret) | |
102 | pr_debug("Failed to set target on CPU:%d. ret:%d\n", | |
103 | cpu->cpu, ret); | |
104 | ||
105 | return ret; | |
106 | } | |
107 | ||
108 | static int cppc_verify_policy(struct cpufreq_policy *policy) | |
109 | { | |
110 | cpufreq_verify_within_cpu_limits(policy); | |
111 | return 0; | |
112 | } | |
113 | ||
114 | static void cppc_cpufreq_stop_cpu(struct cpufreq_policy *policy) | |
115 | { | |
116 | int cpu_num = policy->cpu; | |
41dd6403 | 117 | struct cppc_cpudata *cpu = all_cpu_data[cpu_num]; |
5477fb3b AC |
118 | int ret; |
119 | ||
120 | cpu->perf_ctrls.desired_perf = cpu->perf_caps.lowest_perf; | |
121 | ||
122 | ret = cppc_set_perf(cpu_num, &cpu->perf_ctrls); | |
123 | if (ret) | |
124 | pr_debug("Err setting perf value:%d on CPU:%d. ret:%d\n", | |
125 | cpu->perf_caps.lowest_perf, cpu_num, ret); | |
126 | } | |
127 | ||
128 | static int cppc_cpufreq_cpu_init(struct cpufreq_policy *policy) | |
129 | { | |
41dd6403 | 130 | struct cppc_cpudata *cpu; |
5477fb3b AC |
131 | unsigned int cpu_num = policy->cpu; |
132 | int ret = 0; | |
133 | ||
134 | cpu = all_cpu_data[policy->cpu]; | |
135 | ||
136 | cpu->cpu = cpu_num; | |
137 | ret = cppc_get_perf_caps(policy->cpu, &cpu->perf_caps); | |
138 | ||
139 | if (ret) { | |
140 | pr_debug("Err reading CPU%d perf capabilities. ret:%d\n", | |
141 | cpu_num, ret); | |
142 | return ret; | |
143 | } | |
144 | ||
ad38677d AS |
145 | cppc_dmi_max_khz = cppc_get_dmi_max_khz(); |
146 | ||
73808d0f PP |
147 | /* |
148 | * Set min to lowest nonlinear perf to avoid any efficiency penalty (see | |
149 | * Section 8.4.7.1.1.5 of ACPI 6.1 spec) | |
150 | */ | |
151 | policy->min = cpu->perf_caps.lowest_nonlinear_perf * cppc_dmi_max_khz / | |
152 | cpu->perf_caps.highest_perf; | |
ad38677d | 153 | policy->max = cppc_dmi_max_khz; |
73808d0f PP |
154 | |
155 | /* | |
156 | * Set cpuinfo.min_freq to Lowest to make the full range of performance | |
157 | * available if userspace wants to use any perf between lowest & lowest | |
158 | * nonlinear perf | |
159 | */ | |
160 | policy->cpuinfo.min_freq = cpu->perf_caps.lowest_perf * cppc_dmi_max_khz / | |
161 | cpu->perf_caps.highest_perf; | |
162 | policy->cpuinfo.max_freq = cppc_dmi_max_khz; | |
163 | ||
be8b88d7 | 164 | policy->cpuinfo.transition_latency = cppc_get_transition_latency(cpu_num); |
9dc17917 | 165 | policy->shared_type = cpu->shared_type; |
5477fb3b AC |
166 | |
167 | if (policy->shared_type == CPUFREQ_SHARED_TYPE_ANY) | |
168 | cpumask_copy(policy->cpus, cpu->shared_cpu_map); | |
9dc17917 | 169 | else if (policy->shared_type == CPUFREQ_SHARED_TYPE_ALL) { |
5477fb3b AC |
170 | /* Support only SW_ANY for now. */ |
171 | pr_debug("Unsupported CPU co-ord type\n"); | |
172 | return -EFAULT; | |
173 | } | |
174 | ||
175 | cpumask_set_cpu(policy->cpu, policy->cpus); | |
176 | cpu->cur_policy = policy; | |
177 | ||
178 | /* Set policy->cur to max now. The governors will adjust later. */ | |
ad38677d AS |
179 | policy->cur = cppc_dmi_max_khz; |
180 | cpu->perf_ctrls.desired_perf = cpu->perf_caps.highest_perf; | |
5477fb3b AC |
181 | |
182 | ret = cppc_set_perf(cpu_num, &cpu->perf_ctrls); | |
183 | if (ret) | |
184 | pr_debug("Err setting perf value:%d on CPU:%d. ret:%d\n", | |
185 | cpu->perf_caps.highest_perf, cpu_num, ret); | |
186 | ||
187 | return ret; | |
188 | } | |
189 | ||
190 | static struct cpufreq_driver cppc_cpufreq_driver = { | |
191 | .flags = CPUFREQ_CONST_LOOPS, | |
192 | .verify = cppc_verify_policy, | |
193 | .target = cppc_cpufreq_set_target, | |
194 | .init = cppc_cpufreq_cpu_init, | |
195 | .stop_cpu = cppc_cpufreq_stop_cpu, | |
196 | .name = "cppc_cpufreq", | |
197 | }; | |
198 | ||
199 | static int __init cppc_cpufreq_init(void) | |
200 | { | |
201 | int i, ret = 0; | |
41dd6403 | 202 | struct cppc_cpudata *cpu; |
5477fb3b AC |
203 | |
204 | if (acpi_disabled) | |
205 | return -ENODEV; | |
206 | ||
207 | all_cpu_data = kzalloc(sizeof(void *) * num_possible_cpus(), GFP_KERNEL); | |
208 | if (!all_cpu_data) | |
209 | return -ENOMEM; | |
210 | ||
211 | for_each_possible_cpu(i) { | |
41dd6403 | 212 | all_cpu_data[i] = kzalloc(sizeof(struct cppc_cpudata), GFP_KERNEL); |
5477fb3b AC |
213 | if (!all_cpu_data[i]) |
214 | goto out; | |
215 | ||
216 | cpu = all_cpu_data[i]; | |
217 | if (!zalloc_cpumask_var(&cpu->shared_cpu_map, GFP_KERNEL)) | |
218 | goto out; | |
219 | } | |
220 | ||
221 | ret = acpi_get_psd_map(all_cpu_data); | |
222 | if (ret) { | |
223 | pr_debug("Error parsing PSD data. Aborting cpufreq registration.\n"); | |
224 | goto out; | |
225 | } | |
226 | ||
227 | ret = cpufreq_register_driver(&cppc_cpufreq_driver); | |
228 | if (ret) | |
229 | goto out; | |
230 | ||
231 | return ret; | |
232 | ||
233 | out: | |
234 | for_each_possible_cpu(i) | |
efb2d3be | 235 | kfree(all_cpu_data[i]); |
5477fb3b AC |
236 | |
237 | kfree(all_cpu_data); | |
238 | return -ENODEV; | |
239 | } | |
240 | ||
a29a1e76 AC |
241 | static void __exit cppc_cpufreq_exit(void) |
242 | { | |
41dd6403 | 243 | struct cppc_cpudata *cpu; |
a29a1e76 AC |
244 | int i; |
245 | ||
246 | cpufreq_unregister_driver(&cppc_cpufreq_driver); | |
247 | ||
248 | for_each_possible_cpu(i) { | |
249 | cpu = all_cpu_data[i]; | |
250 | free_cpumask_var(cpu->shared_cpu_map); | |
251 | kfree(cpu); | |
252 | } | |
253 | ||
254 | kfree(all_cpu_data); | |
255 | } | |
256 | ||
257 | module_exit(cppc_cpufreq_exit); | |
258 | MODULE_AUTHOR("Ashwin Chaugule"); | |
259 | MODULE_DESCRIPTION("CPUFreq driver based on the ACPI CPPC v5.0+ spec"); | |
260 | MODULE_LICENSE("GPL"); | |
261 | ||
5477fb3b | 262 | late_initcall(cppc_cpufreq_init); |
974f8649 PP |
263 | |
264 | static const struct acpi_device_id cppc_acpi_ids[] = { | |
265 | {ACPI_PROCESSOR_DEVICE_HID, }, | |
266 | {} | |
267 | }; | |
268 | ||
269 | MODULE_DEVICE_TABLE(acpi, cppc_acpi_ids); |