cpupower: Add AMD P-State sysfs definition and access helper

Introduce the marco definitions and access helper function for
AMD P-State sysfs interfaces such as each performance goals and frequency
levels in amd helper file. They will be used to read the sysfs attribute
from AMD P-State cpufreq driver for cpupower utilities.

Reviewed-by: Shuah Khan <[e-mail]>
Signed-off-by: Huang Rui <[e-mail]>
Signed-off-by: Shuah Khan <[e-mail]>

tools/power/cpupower/utils/helpers/amd.c

···
 #include <pci/pci.h>
 
 #include "helpers/helpers.h"
+#include "cpufreq.h"
+#include "acpi_cppc.h"
 
+/* ACPI P-States Helper Functions for AMD Processors ***************/
 #define MSR_AMD_PSTATE_STATUS	0xc0010063
 #define MSR_AMD_PSTATE		0xc0010064
 #define MSR_AMD_PSTATE_LIMIT	0xc0010061
···
 	pci_cleanup(pci_acc);
 	return 0;
 }
+
+/* ACPI P-States Helper Functions for AMD Processors ***************/
+
+/* AMD P-State Helper Functions ************************************/
+enum amd_pstate_value {
+	AMD_PSTATE_HIGHEST_PERF,
+	AMD_PSTATE_MAX_FREQ,
+	AMD_PSTATE_LOWEST_NONLINEAR_FREQ,
+	MAX_AMD_PSTATE_VALUE_READ_FILES,
+};
+
+static const char *amd_pstate_value_files[MAX_AMD_PSTATE_VALUE_READ_FILES] = {
+	[AMD_PSTATE_HIGHEST_PERF] = "amd_pstate_highest_perf",
+	[AMD_PSTATE_MAX_FREQ] = "amd_pstate_max_freq",
+	[AMD_PSTATE_LOWEST_NONLINEAR_FREQ] = "amd_pstate_lowest_nonlinear_freq",
+};
+
+static unsigned long amd_pstate_get_data(unsigned int cpu,
+					 enum amd_pstate_value value)
+{
+	return cpufreq_get_sysfs_value_from_table(cpu,
+						  amd_pstate_value_files,
+						  value,
+						  MAX_AMD_PSTATE_VALUE_READ_FILES);
+}
+
+/* AMD P-State Helper Functions ************************************/
 #endif /* defined(__i386__) || defined(__x86_64__) */