cpupower: Do detect IDA (opportunistic processor performance) via cpuid
[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 #define MSR_NEHALEM_TURBO_RATIO_LIMIT   0x1ad
15
16 /*
17  * read_msr
18  *
19  * Will return 0 on success and -1 on failure.
20  * Possible errno values could be:
21  * EFAULT -If the read/write did not fully complete
22  * EIO    -If the CPU does not support MSRs
23  * ENXIO  -If the CPU does not exist
24  */
25
26 int read_msr(int cpu, unsigned int idx, unsigned long long *val)
27 {
28         int fd;
29         char msr_file_name[64];
30
31         sprintf(msr_file_name, "/dev/cpu/%d/msr", cpu);
32         fd = open(msr_file_name, O_RDONLY);
33         if (fd < 0)
34                 return -1;
35         if (lseek(fd, idx, SEEK_CUR) == -1)
36                 goto err;
37         if (read(fd, val, sizeof *val) != sizeof *val)
38                 goto err;
39         close(fd);
40         return 0;
41  err:
42         close(fd);
43         return -1;
44 }
45
46 /*
47  * write_msr
48  *
49  * Will return 0 on success and -1 on failure.
50  * Possible errno values could be:
51  * EFAULT -If the read/write did not fully complete
52  * EIO    -If the CPU does not support MSRs
53  * ENXIO  -If the CPU does not exist
54  */
55 int write_msr(int cpu, unsigned int idx, unsigned long long val)
56 {
57         int fd;
58         char msr_file_name[64];
59
60         sprintf(msr_file_name, "/dev/cpu/%d/msr", cpu);
61         fd = open(msr_file_name, O_WRONLY);
62         if (fd < 0)
63                 return -1;
64         if (lseek(fd, idx, SEEK_CUR) == -1)
65                 goto err;
66         if (write(fd, &val, sizeof val) != sizeof val)
67                 goto err;
68         close(fd);
69         return 0;
70  err:
71         close(fd);
72         return -1;
73 }
74
75 int msr_intel_get_perf_bias(unsigned int cpu)
76 {
77         unsigned long long val;
78         int ret;
79
80         if (!(cpupower_cpu_info.caps & CPUPOWER_CAP_PERF_BIAS))
81                 return -1;
82
83         ret = read_msr(cpu, MSR_IA32_ENERGY_PERF_BIAS, &val);
84         if (ret)
85                 return ret;
86         return val;
87 }
88
89 int msr_intel_set_perf_bias(unsigned int cpu, unsigned int val)
90 {
91         int ret;
92
93         if (!(cpupower_cpu_info.caps & CPUPOWER_CAP_PERF_BIAS))
94                 return -1;
95
96         ret = write_msr(cpu, MSR_IA32_ENERGY_PERF_BIAS, val);
97         if (ret)
98                 return ret;
99         return 0;
100 }
101
102 unsigned long long msr_intel_get_turbo_ratio(unsigned int cpu)
103 {
104         unsigned long long val;
105         int ret;
106
107         if (!(cpupower_cpu_info.caps & CPUPOWER_CAP_HAS_TURBO_RATIO))
108                 return -1;
109
110         ret = read_msr(cpu, MSR_NEHALEM_TURBO_RATIO_LIMIT, &val);
111         if (ret)
112                 return ret;
113         return val;
114 }
115 #endif