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kernel/linux-rt-4.4.41/tools/power/cpupower/utils/helpers/msr.c 2.29 KB
5113f6f70   김현기   kernel add
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  #if defined(__i386__) || defined(__x86_64__)
  
  #include <fcntl.h>
  #include <stdio.h>
  #include <unistd.h>
  #include <stdint.h>
  
  #include "helpers/helpers.h"
  
  /* Intel specific MSRs */
  #define MSR_IA32_PERF_STATUS		0x198
  #define MSR_IA32_MISC_ENABLES		0x1a0
  #define MSR_IA32_ENERGY_PERF_BIAS	0x1b0
  #define MSR_NEHALEM_TURBO_RATIO_LIMIT	0x1ad
  
  /*
   * read_msr
   *
   * Will return 0 on success and -1 on failure.
   * Possible errno values could be:
   * EFAULT -If the read/write did not fully complete
   * EIO    -If the CPU does not support MSRs
   * ENXIO  -If the CPU does not exist
   */
  
  int read_msr(int cpu, unsigned int idx, unsigned long long *val)
  {
  	int fd;
  	char msr_file_name[64];
  
  	sprintf(msr_file_name, "/dev/cpu/%d/msr", cpu);
  	fd = open(msr_file_name, O_RDONLY);
  	if (fd < 0)
  		return -1;
  	if (lseek(fd, idx, SEEK_CUR) == -1)
  		goto err;
  	if (read(fd, val, sizeof *val) != sizeof *val)
  		goto err;
  	close(fd);
  	return 0;
   err:
  	close(fd);
  	return -1;
  }
  
  /*
   * write_msr
   *
   * Will return 0 on success and -1 on failure.
   * Possible errno values could be:
   * EFAULT -If the read/write did not fully complete
   * EIO    -If the CPU does not support MSRs
   * ENXIO  -If the CPU does not exist
   */
  int write_msr(int cpu, unsigned int idx, unsigned long long val)
  {
  	int fd;
  	char msr_file_name[64];
  
  	sprintf(msr_file_name, "/dev/cpu/%d/msr", cpu);
  	fd = open(msr_file_name, O_WRONLY);
  	if (fd < 0)
  		return -1;
  	if (lseek(fd, idx, SEEK_CUR) == -1)
  		goto err;
  	if (write(fd, &val, sizeof val) != sizeof val)
  		goto err;
  	close(fd);
  	return 0;
   err:
  	close(fd);
  	return -1;
  }
  
  int msr_intel_get_perf_bias(unsigned int cpu)
  {
  	unsigned long long val;
  	int ret;
  
  	if (!(cpupower_cpu_info.caps & CPUPOWER_CAP_PERF_BIAS))
  		return -1;
  
  	ret = read_msr(cpu, MSR_IA32_ENERGY_PERF_BIAS, &val);
  	if (ret)
  		return ret;
  	return val;
  }
  
  int msr_intel_set_perf_bias(unsigned int cpu, unsigned int val)
  {
  	int ret;
  
  	if (!(cpupower_cpu_info.caps & CPUPOWER_CAP_PERF_BIAS))
  		return -1;
  
  	ret = write_msr(cpu, MSR_IA32_ENERGY_PERF_BIAS, val);
  	if (ret)
  		return ret;
  	return 0;
  }
  
  unsigned long long msr_intel_get_turbo_ratio(unsigned int cpu)
  {
  	unsigned long long val;
  	int ret;
  
  	if (!(cpupower_cpu_info.caps & CPUPOWER_CAP_HAS_TURBO_RATIO))
  		return -1;
  
  	ret = read_msr(cpu, MSR_NEHALEM_TURBO_RATIO_LIMIT, &val);
  	if (ret)
  		return ret;
  	return val;
  }
  #endif