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2504ba9f | 1 | // SPDX-License-Identifier: GPL-2.0-only |
e7ddf4b7 SK |
2 | /* |
3 | * SFI Performance States Driver | |
4 | * | |
e7ddf4b7 SK |
5 | * Author: Vishwesh M Rudramuni <vishwesh.m.rudramuni@intel.com> |
6 | * Author: Srinidhi Kasagar <srinidhi.kasagar@intel.com> | |
7 | */ | |
8 | ||
9 | #include <linux/cpufreq.h> | |
10 | #include <linux/init.h> | |
11 | #include <linux/kernel.h> | |
12 | #include <linux/module.h> | |
13 | #include <linux/sfi.h> | |
14 | #include <linux/slab.h> | |
15 | #include <linux/smp.h> | |
16 | ||
17 | #include <asm/msr.h> | |
18 | ||
0370f0f9 | 19 | static struct cpufreq_frequency_table *freq_table; |
e7ddf4b7 SK |
20 | static struct sfi_freq_table_entry *sfi_cpufreq_array; |
21 | static int num_freq_table_entries; | |
22 | ||
23 | static int sfi_parse_freq(struct sfi_table_header *table) | |
24 | { | |
25 | struct sfi_table_simple *sb; | |
26 | struct sfi_freq_table_entry *pentry; | |
27 | int totallen; | |
28 | ||
29 | sb = (struct sfi_table_simple *)table; | |
30 | num_freq_table_entries = SFI_GET_NUM_ENTRIES(sb, | |
31 | struct sfi_freq_table_entry); | |
32 | if (num_freq_table_entries <= 1) { | |
33 | pr_err("No p-states discovered\n"); | |
34 | return -ENODEV; | |
35 | } | |
36 | ||
37 | pentry = (struct sfi_freq_table_entry *)sb->pentry; | |
38 | totallen = num_freq_table_entries * sizeof(*pentry); | |
39 | ||
a482e556 | 40 | sfi_cpufreq_array = kmemdup(pentry, totallen, GFP_KERNEL); |
e7ddf4b7 SK |
41 | if (!sfi_cpufreq_array) |
42 | return -ENOMEM; | |
43 | ||
e7ddf4b7 SK |
44 | return 0; |
45 | } | |
46 | ||
47 | static int sfi_cpufreq_target(struct cpufreq_policy *policy, unsigned int index) | |
48 | { | |
49 | unsigned int next_perf_state = 0; /* Index into perf table */ | |
50 | u32 lo, hi; | |
51 | ||
52 | next_perf_state = policy->freq_table[index].driver_data; | |
53 | ||
54 | rdmsr_on_cpu(policy->cpu, MSR_IA32_PERF_CTL, &lo, &hi); | |
55 | lo = (lo & ~INTEL_PERF_CTL_MASK) | | |
56 | ((u32) sfi_cpufreq_array[next_perf_state].ctrl_val & | |
57 | INTEL_PERF_CTL_MASK); | |
58 | wrmsr_on_cpu(policy->cpu, MSR_IA32_PERF_CTL, lo, hi); | |
59 | ||
60 | return 0; | |
61 | } | |
62 | ||
63 | static int sfi_cpufreq_cpu_init(struct cpufreq_policy *policy) | |
64 | { | |
65 | policy->shared_type = CPUFREQ_SHARED_TYPE_HW; | |
66 | policy->cpuinfo.transition_latency = 100000; /* 100us */ | |
54a277eb | 67 | policy->freq_table = freq_table; |
e7ddf4b7 | 68 | |
54a277eb | 69 | return 0; |
e7ddf4b7 SK |
70 | } |
71 | ||
72 | static struct cpufreq_driver sfi_cpufreq_driver = { | |
73 | .flags = CPUFREQ_CONST_LOOPS, | |
74 | .verify = cpufreq_generic_frequency_table_verify, | |
75 | .target_index = sfi_cpufreq_target, | |
76 | .init = sfi_cpufreq_cpu_init, | |
77 | .name = "sfi-cpufreq", | |
78 | .attr = cpufreq_generic_attr, | |
79 | }; | |
80 | ||
81 | static int __init sfi_cpufreq_init(void) | |
82 | { | |
83 | int ret, i; | |
84 | ||
85 | /* parse the freq table from SFI */ | |
86 | ret = sfi_table_parse(SFI_SIG_FREQ, NULL, NULL, sfi_parse_freq); | |
87 | if (ret) | |
88 | return ret; | |
89 | ||
6396bb22 KC |
90 | freq_table = kcalloc(num_freq_table_entries + 1, sizeof(*freq_table), |
91 | GFP_KERNEL); | |
e7ddf4b7 SK |
92 | if (!freq_table) { |
93 | ret = -ENOMEM; | |
94 | goto err_free_array; | |
95 | } | |
96 | ||
97 | for (i = 0; i < num_freq_table_entries; i++) { | |
98 | freq_table[i].driver_data = i; | |
99 | freq_table[i].frequency = sfi_cpufreq_array[i].freq_mhz * 1000; | |
100 | } | |
101 | freq_table[i].frequency = CPUFREQ_TABLE_END; | |
102 | ||
103 | ret = cpufreq_register_driver(&sfi_cpufreq_driver); | |
104 | if (ret) | |
105 | goto err_free_tbl; | |
106 | ||
107 | return ret; | |
108 | ||
109 | err_free_tbl: | |
110 | kfree(freq_table); | |
111 | err_free_array: | |
112 | kfree(sfi_cpufreq_array); | |
113 | return ret; | |
114 | } | |
115 | late_initcall(sfi_cpufreq_init); | |
116 | ||
117 | static void __exit sfi_cpufreq_exit(void) | |
118 | { | |
119 | cpufreq_unregister_driver(&sfi_cpufreq_driver); | |
120 | kfree(freq_table); | |
121 | kfree(sfi_cpufreq_array); | |
122 | } | |
123 | module_exit(sfi_cpufreq_exit); | |
124 | ||
125 | MODULE_AUTHOR("Vishwesh M Rudramuni <vishwesh.m.rudramuni@intel.com>"); | |
126 | MODULE_DESCRIPTION("SFI Performance-States Driver"); | |
127 | MODULE_LICENSE("GPL"); |