cpupowerutils - cpufrequtils extended with quite some features
[linux-2.6.git] / tools / power / cpupower / utils / helpers / msr.c
1 #if defined(__i386__) || defined(__x86_64__)
2
3 #include <fcntl.h>
4 #include <stdio.h>
5 #include <unistd.h>
6 #include <stdint.h>
7
8 #include "helpers/helpers.h"
9
10 /* Intel specific MSRs */
11 #define MSR_IA32_PERF_STATUS            0x198
12 #define MSR_IA32_MISC_ENABLES           0x1a0
13 #define MSR_IA32_ENERGY_PERF_BIAS       0x1b0
14
15 /*
16  * read_msr
17  *
18  * Will return 0 on success and -1 on failure.
19  * Possible errno values could be:
20  * EFAULT -If the read/write did not fully complete
21  * EIO    -If the CPU does not support MSRs
22  * ENXIO  -If the CPU does not exist
23  */
24
25 int read_msr(int cpu, unsigned int idx, unsigned long long *val)
26 {
27         int fd;
28         char msr_file_name[64];
29
30         sprintf(msr_file_name, "/dev/cpu/%d/msr", cpu);
31         fd = open(msr_file_name, O_RDONLY);
32         if (fd < 0)
33                 return -1;
34         if (lseek(fd, idx, SEEK_CUR) == -1)
35                 goto err;
36         if (read(fd, val, sizeof *val) != sizeof *val)
37                 goto err;
38         close(fd);
39         return 0;
40  err:
41         close(fd);
42         return -1;
43 }
44
45 /*
46  * write_msr
47  *
48  * Will return 0 on success and -1 on failure.
49  * Possible errno values could be:
50  * EFAULT -If the read/write did not fully complete
51  * EIO    -If the CPU does not support MSRs
52  * ENXIO  -If the CPU does not exist
53  */
54 int write_msr(int cpu, unsigned int idx, unsigned long long val)
55 {
56         int fd;
57         char msr_file_name[64];
58
59         sprintf(msr_file_name, "/dev/cpu/%d/msr", cpu);
60         fd = open(msr_file_name, O_WRONLY);
61         if (fd < 0)
62                 return -1;
63         if (lseek(fd, idx, SEEK_CUR) == -1)
64                 goto err;
65         if (write(fd, &val, sizeof val) != sizeof val)
66                 goto err;
67         close(fd);
68         return 0;
69  err:
70         close(fd);
71         return -1;
72 }
73
74 int msr_intel_has_boost_support(unsigned int cpu)
75 {
76         unsigned long long misc_enables;
77         int ret;
78
79         ret = read_msr(cpu, MSR_IA32_MISC_ENABLES, &misc_enables);
80         if (ret)
81                 return ret;
82         return (misc_enables >> 38) & 0x1;
83 }
84
85 int msr_intel_boost_is_active(unsigned int cpu)
86 {
87         unsigned long long perf_status;
88         int ret;
89
90         ret = read_msr(cpu, MSR_IA32_PERF_STATUS, &perf_status);
91         if (ret)
92                 return ret;
93         return (perf_status >> 32) & 0x1;
94 }
95
96 int msr_intel_get_perf_bias(unsigned int cpu)
97 {
98         unsigned long long val;
99         int ret;
100
101         if (!(cpupower_cpu_info.caps & CPUPOWER_CAP_PERF_BIAS))
102                 return -1;
103
104         ret = read_msr(cpu, MSR_IA32_ENERGY_PERF_BIAS, &val);
105         if (ret)
106                 return ret;
107         return val;
108 }
109
110 int msr_intel_set_perf_bias(unsigned int cpu, unsigned int val)
111 {
112         int ret;
113
114         if (!(cpupower_cpu_info.caps & CPUPOWER_CAP_PERF_BIAS))
115                 return -1;
116
117         ret = write_msr(cpu, MSR_IA32_ENERGY_PERF_BIAS, val);
118         if (ret)
119                 return ret;
120         return 0;
121 }
122 #endif