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1 | /* |
2 | * SFI Performance States Driver | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or modify | |
5 | * it under the terms of the GNU General Public License as published by | |
6 | * the Free Software Foundation; either version 2 of the License. | |
7 | * | |
8 | * This program is distributed in the hope that it will be useful, but | |
9 | * WITHOUT ANY WARRANTY; without even the implied warranty of | |
10 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
11 | * General Public License for more details. | |
12 | * | |
13 | * Author: Vishwesh M Rudramuni <vishwesh.m.rudramuni@intel.com> | |
14 | * Author: Srinidhi Kasagar <srinidhi.kasagar@intel.com> | |
15 | */ | |
16 | ||
17 | #include <linux/cpufreq.h> | |
18 | #include <linux/init.h> | |
19 | #include <linux/kernel.h> | |
20 | #include <linux/module.h> | |
21 | #include <linux/sfi.h> | |
22 | #include <linux/slab.h> | |
23 | #include <linux/smp.h> | |
24 | ||
25 | #include <asm/msr.h> | |
26 | ||
27 | struct cpufreq_frequency_table *freq_table; | |
28 | static struct sfi_freq_table_entry *sfi_cpufreq_array; | |
29 | static int num_freq_table_entries; | |
30 | ||
31 | static int sfi_parse_freq(struct sfi_table_header *table) | |
32 | { | |
33 | struct sfi_table_simple *sb; | |
34 | struct sfi_freq_table_entry *pentry; | |
35 | int totallen; | |
36 | ||
37 | sb = (struct sfi_table_simple *)table; | |
38 | num_freq_table_entries = SFI_GET_NUM_ENTRIES(sb, | |
39 | struct sfi_freq_table_entry); | |
40 | if (num_freq_table_entries <= 1) { | |
41 | pr_err("No p-states discovered\n"); | |
42 | return -ENODEV; | |
43 | } | |
44 | ||
45 | pentry = (struct sfi_freq_table_entry *)sb->pentry; | |
46 | totallen = num_freq_table_entries * sizeof(*pentry); | |
47 | ||
a482e556 | 48 | sfi_cpufreq_array = kmemdup(pentry, totallen, GFP_KERNEL); |
e7ddf4b7 SK |
49 | if (!sfi_cpufreq_array) |
50 | return -ENOMEM; | |
51 | ||
e7ddf4b7 SK |
52 | return 0; |
53 | } | |
54 | ||
55 | static int sfi_cpufreq_target(struct cpufreq_policy *policy, unsigned int index) | |
56 | { | |
57 | unsigned int next_perf_state = 0; /* Index into perf table */ | |
58 | u32 lo, hi; | |
59 | ||
60 | next_perf_state = policy->freq_table[index].driver_data; | |
61 | ||
62 | rdmsr_on_cpu(policy->cpu, MSR_IA32_PERF_CTL, &lo, &hi); | |
63 | lo = (lo & ~INTEL_PERF_CTL_MASK) | | |
64 | ((u32) sfi_cpufreq_array[next_perf_state].ctrl_val & | |
65 | INTEL_PERF_CTL_MASK); | |
66 | wrmsr_on_cpu(policy->cpu, MSR_IA32_PERF_CTL, lo, hi); | |
67 | ||
68 | return 0; | |
69 | } | |
70 | ||
71 | static int sfi_cpufreq_cpu_init(struct cpufreq_policy *policy) | |
72 | { | |
73 | policy->shared_type = CPUFREQ_SHARED_TYPE_HW; | |
74 | policy->cpuinfo.transition_latency = 100000; /* 100us */ | |
75 | ||
76 | return cpufreq_table_validate_and_show(policy, freq_table); | |
77 | } | |
78 | ||
79 | static struct cpufreq_driver sfi_cpufreq_driver = { | |
80 | .flags = CPUFREQ_CONST_LOOPS, | |
81 | .verify = cpufreq_generic_frequency_table_verify, | |
82 | .target_index = sfi_cpufreq_target, | |
83 | .init = sfi_cpufreq_cpu_init, | |
84 | .name = "sfi-cpufreq", | |
85 | .attr = cpufreq_generic_attr, | |
86 | }; | |
87 | ||
88 | static int __init sfi_cpufreq_init(void) | |
89 | { | |
90 | int ret, i; | |
91 | ||
92 | /* parse the freq table from SFI */ | |
93 | ret = sfi_table_parse(SFI_SIG_FREQ, NULL, NULL, sfi_parse_freq); | |
94 | if (ret) | |
95 | return ret; | |
96 | ||
97 | freq_table = kzalloc(sizeof(*freq_table) * | |
98 | (num_freq_table_entries + 1), GFP_KERNEL); | |
99 | if (!freq_table) { | |
100 | ret = -ENOMEM; | |
101 | goto err_free_array; | |
102 | } | |
103 | ||
104 | for (i = 0; i < num_freq_table_entries; i++) { | |
105 | freq_table[i].driver_data = i; | |
106 | freq_table[i].frequency = sfi_cpufreq_array[i].freq_mhz * 1000; | |
107 | } | |
108 | freq_table[i].frequency = CPUFREQ_TABLE_END; | |
109 | ||
110 | ret = cpufreq_register_driver(&sfi_cpufreq_driver); | |
111 | if (ret) | |
112 | goto err_free_tbl; | |
113 | ||
114 | return ret; | |
115 | ||
116 | err_free_tbl: | |
117 | kfree(freq_table); | |
118 | err_free_array: | |
119 | kfree(sfi_cpufreq_array); | |
120 | return ret; | |
121 | } | |
122 | late_initcall(sfi_cpufreq_init); | |
123 | ||
124 | static void __exit sfi_cpufreq_exit(void) | |
125 | { | |
126 | cpufreq_unregister_driver(&sfi_cpufreq_driver); | |
127 | kfree(freq_table); | |
128 | kfree(sfi_cpufreq_array); | |
129 | } | |
130 | module_exit(sfi_cpufreq_exit); | |
131 | ||
132 | MODULE_AUTHOR("Vishwesh M Rudramuni <vishwesh.m.rudramuni@intel.com>"); | |
133 | MODULE_DESCRIPTION("SFI Performance-States Driver"); | |
134 | MODULE_LICENSE("GPL"); |