[v3] libs/power: add p-state driver compatibility

diff --git a/lib/librte_power/Makefile b/lib/librte_power/Makefile
index 9bec668..ab77152 100644
--- a/lib/librte_power/Makefile
+++ b/lib/librte_power/Makefile
@@ -6,6 +6,7 @@  include $(RTE_SDK)/mk/rte.vars.mk
 # library name
 LIB = librte_power.a
 
+CFLAGS += -DALLOW_EXPERIMENTAL_API
 CFLAGS += $(WERROR_FLAGS) -I$(SRCDIR) -O3 -fno-strict-aliasing
 LDLIBS += -lrte_eal -lrte_timer
 
@@ -17,6 +18,7 @@  LIBABIVER := 1
 SRCS-$(CONFIG_RTE_LIBRTE_POWER) := rte_power.c power_acpi_cpufreq.c
 SRCS-$(CONFIG_RTE_LIBRTE_POWER) += power_kvm_vm.c guest_channel.c
 SRCS-$(CONFIG_RTE_LIBRTE_POWER) += rte_power_empty_poll.c
+SRCS-$(CONFIG_RTE_LIBRTE_POWER) += power_pstate_cpufreq.c
 
 # install this header file
 SYMLINK-$(CONFIG_RTE_LIBRTE_POWER)-include := rte_power.h  rte_power_empty_poll.h
diff --git a/lib/librte_power/meson.build b/lib/librte_power/meson.build
index 9ed8b56..14a2128 100644
--- a/lib/librte_power/meson.build
+++ b/lib/librte_power/meson.build
@@ -6,6 +6,6 @@  if host_machine.system() != 'linux'
 endif
 sources = files('rte_power.c', 'power_acpi_cpufreq.c',
 		'power_kvm_vm.c', 'guest_channel.c',
-		'rte_power_empty_poll.c')
+		'rte_power_empty_poll.c',
+		'power_pstate_cpufreq.c')
 headers = files('rte_power.h','rte_power_empty_poll.h')
-deps += ['timer']
diff --git a/lib/librte_power/power_pstate_cpufreq.c b/lib/librte_power/power_pstate_cpufreq.c
new file mode 100644
index 0000000..dd6a20c
--- /dev/null
+++ b/lib/librte_power/power_pstate_cpufreq.c
@@ -0,0 +1,770 @@ 
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright(c) 2018-2018 Intel Corporation
+ */
+
+#include <stdio.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <signal.h>
+#include <limits.h>
+#include <errno.h>
+
+#include <rte_memcpy.h>
+#include <rte_atomic.h>
+
+#include "power_pstate_cpufreq.h"
+#include "power_common.h"
+
+
+#ifdef RTE_LIBRTE_POWER_DEBUG
+#define POWER_DEBUG_TRACE(fmt, args...) do { \
+		RTE_LOG(ERR, POWER, "%s: " fmt, __func__, ## args); \
+} while (0)
+#else
+#define POWER_DEBUG_TRACE(fmt, args...)
+#endif
+
+#define FOPEN_OR_ERR_RET(f, retval) do { \
+		if ((f) == NULL) { \
+			RTE_LOG(ERR, POWER, "File not openned\n"); \
+			return retval; \
+		} \
+} while (0)
+
+#define FOPS_OR_NULL_GOTO(ret, label) do { \
+		if ((ret) == NULL) { \
+			RTE_LOG(ERR, POWER, "fgets returns nothing\n"); \
+			goto label; \
+		} \
+} while (0)
+
+#define FOPS_OR_ERR_GOTO(ret, label) do { \
+		if ((ret) < 0) { \
+			RTE_LOG(ERR, POWER, "File operations failed\n"); \
+			goto label; \
+		} \
+} while (0)
+
+
+#define POWER_CONVERT_TO_DECIMAL 10
+#define BUS_FREQ     100000
+
+#define POWER_GOVERNOR_PERF "performance"
+#define POWER_SYSFILE_GOVERNOR  \
+		"/sys/devices/system/cpu/cpu%u/cpufreq/scaling_governor"
+#define POWER_SYSFILE_MAX_FREQ \
+		"/sys/devices/system/cpu/cpu%u/cpufreq/scaling_max_freq"
+#define POWER_SYSFILE_MIN_FREQ  \
+		"/sys/devices/system/cpu/cpu%u/cpufreq/scaling_min_freq"
+#define POWER_SYSFILE_CUR_FREQ  \
+		"/sys/devices/system/cpu/cpu%u/cpufreq/scaling_cur_freq"
+#define POWER_SYSFILE_BASE_MAX_FREQ \
+		"/sys/devices/system/cpu/cpu%u/cpufreq/cpuinfo_max_freq"
+#define POWER_SYSFILE_BASE_MIN_FREQ  \
+		"/sys/devices/system/cpu/cpu%u/cpufreq/cpuinfo_min_freq"
+#define POWER_MSR_PATH  "/dev/cpu/%u/msr"
+
+/*
+ * MSR related
+ */
+#define PLATFORM_INFO     0x0CE
+#define NON_TURBO_MASK    0xFF00
+#define NON_TURBO_OFFSET  0x8
+
+
+enum power_state {
+	POWER_IDLE = 0,
+	POWER_ONGOING,
+	POWER_USED,
+	POWER_UNKNOWN
+};
+
+struct pstate_power_info {
+	unsigned int lcore_id;               /**< Logical core id */
+	uint32_t freqs[RTE_MAX_LCORE_FREQS]; /**< Frequency array */
+	uint32_t nb_freqs;                   /**< number of available freqs */
+	FILE *f_cur_min;                     /**< FD of scaling_min */
+	FILE *f_cur_max;                     /**< FD of scaling_max */
+	char governor_ori[32];               /**< Original governor name */
+	uint32_t curr_idx;                   /**< Freq index in freqs array */
+	uint32_t non_turbo_max_ratio;        /**< Non Turbo Max ratio  */
+	uint32_t sys_max_freq;               /**< system wide max freq  */
+	volatile uint32_t state;             /**< Power in use state */
+	uint16_t turbo_available;            /**< Turbo Boost available */
+	uint16_t turbo_enable;               /**< Turbo Boost enable/disable */
+} __rte_cache_aligned;
+
+
+static struct pstate_power_info lcore_power_info[RTE_MAX_LCORE];
+
+/**
+ * It is to read the specific MSR.
+ */
+
+static int32_t
+power_rdmsr(int msr, uint64_t *val, unsigned int lcore_id)
+{
+	int fd, ret;
+	char fullpath[PATH_MAX];
+
+	snprintf(fullpath, sizeof(fullpath), POWER_MSR_PATH, lcore_id);
+
+	fd = open(fullpath, O_RDONLY);
+
+	if (fd < 0) {
+		RTE_LOG(ERR, POWER, "Error opening '%s': %s\n", fullpath,
+				 strerror(errno));
+		return fd;
+	}
+
+	ret = pread(fd, val, sizeof(uint64_t), msr);
+
+	if (ret < 0) {
+		RTE_LOG(ERR, POWER, "Error reading '%s': %s\n", fullpath,
+				 strerror(errno));
+		goto out;
+	}
+
+	POWER_DEBUG_TRACE("MSR Path %s, offset 0x%X for lcore %u\n",
+			fullpath, msr, lcore_id);
+
+	POWER_DEBUG_TRACE("Ret value %d, content is 0x%lx\n", ret, *val);
+
+out:	close(fd);
+	return ret;
+}
+
+/**
+ * It is to fopen the sys file for the future setting the lcore frequency.
+ */
+static int
+power_init_for_setting_freq(struct pstate_power_info *pi)
+{
+	FILE *f_min, *f_max;
+	char fullpath_min[PATH_MAX];
+	char fullpath_max[PATH_MAX];
+	uint64_t max_non_turbo = 0;
+
+	snprintf(fullpath_min, sizeof(fullpath_min), POWER_SYSFILE_MIN_FREQ,
+			pi->lcore_id);
+
+	f_min = fopen(fullpath_min, "rw+");
+	FOPEN_OR_ERR_RET(f_min, -1);
+
+	snprintf(fullpath_max, sizeof(fullpath_max), POWER_SYSFILE_MAX_FREQ,
+			pi->lcore_id);
+
+	f_max = fopen(fullpath_max, "rw+");
+	FOPEN_OR_ERR_RET(f_max, -1);
+
+	pi->f_cur_min = f_min;
+	pi->f_cur_max = f_max;
+
+	/* Add MSR read to detect turbo status */
+
+	if (power_rdmsr(PLATFORM_INFO, &max_non_turbo, pi->lcore_id) < 0)
+		return -1;
+
+	max_non_turbo = (max_non_turbo&NON_TURBO_MASK)>>NON_TURBO_OFFSET;
+
+	POWER_DEBUG_TRACE("no turbo perf %lu\n", max_non_turbo);
+
+	pi->non_turbo_max_ratio = max_non_turbo;
+
+	return 0;
+}
+
+static int
+set_freq_internal(struct pstate_power_info *pi, uint32_t idx)
+{
+	uint32_t target_freq = 0;
+
+	if (idx >= RTE_MAX_LCORE_FREQS || idx >= pi->nb_freqs) {
+		RTE_LOG(ERR, POWER, "Invalid frequency index %u, which "
+				"should be less than %u\n", idx, pi->nb_freqs);
+		return -1;
+	}
+
+	/* Check if it is the same as current */
+	if (idx == pi->curr_idx)
+		return 0;
+
+	/* Because Intel Pstate Driver only allow user change min/max hint
+	 * User need change the min/max as same value.
+	 */
+	if (fseek(pi->f_cur_min, 0, SEEK_SET) < 0) {
+		RTE_LOG(ERR, POWER, "Fail to set file position indicator to 0 "
+				"for setting frequency for lcore %u\n",
+				pi->lcore_id);
+		return -1;
+	}
+
+	if (fseek(pi->f_cur_max, 0, SEEK_SET) < 0) {
+		RTE_LOG(ERR, POWER, "Fail to set file position indicator to 0 "
+				"for setting frequency for lcore %u\n",
+				pi->lcore_id);
+		return -1;
+	}
+
+	/* Turbo is available and enabled, first freq bucket is sys max freq */
+	if (pi->turbo_available && pi->turbo_enable && (idx == 0))
+		target_freq = pi->sys_max_freq;
+	else
+		target_freq = pi->freqs[idx];
+
+	/* Decrease freq, the min freq should be updated first */
+	if (idx  >  pi->curr_idx) {
+
+		if (fprintf(pi->f_cur_min, "%u", target_freq) < 0) {
+			RTE_LOG(ERR, POWER, "Fail to write new frequency for "
+					"lcore %u\n", pi->lcore_id);
+			return -1;
+		}
+
+		if (fprintf(pi->f_cur_max, "%u", target_freq) < 0) {
+			RTE_LOG(ERR, POWER, "Fail to write new frequency for "
+					"lcore %u\n", pi->lcore_id);
+			return -1;
+		}
+
+		POWER_DEBUG_TRACE("Freqency '%u' to be set for lcore %u\n",
+				  target_freq, pi->lcore_id);
+
+		fflush(pi->f_cur_min);
+		fflush(pi->f_cur_max);
+
+	}
+
+	/* Increase freq, the max freq should be updated first */
+	if (idx  <  pi->curr_idx) {
+
+		if (fprintf(pi->f_cur_max, "%u", target_freq) < 0) {
+			RTE_LOG(ERR, POWER, "Fail to write new frequency for "
+					"lcore %u\n", pi->lcore_id);
+			return -1;
+		}
+
+		if (fprintf(pi->f_cur_min, "%u", target_freq) < 0) {
+			RTE_LOG(ERR, POWER, "Fail to write new frequency for "
+					"lcore %u\n", pi->lcore_id);
+			return -1;
+		}
+
+		POWER_DEBUG_TRACE("Freqency '%u' to be set for lcore %u\n",
+				  target_freq, pi->lcore_id);
+
+		fflush(pi->f_cur_max);
+		fflush(pi->f_cur_min);
+	}
+
+	pi->curr_idx = idx;
+
+	return 1;
+}
+
+/**
+ * It is to check the current scaling governor by reading sys file, and then
+ * set it into 'performance' if it is not by writing the sys file. The original
+ * governor will be saved for rolling back.
+ */
+static int
+power_set_governor_performance(struct pstate_power_info *pi)
+{
+	FILE *f;
+	int ret = -1;
+	char buf[BUFSIZ];
+	char fullpath[PATH_MAX];
+	char *s;
+	int val;
+
+	snprintf(fullpath, sizeof(fullpath), POWER_SYSFILE_GOVERNOR,
+			pi->lcore_id);
+	f = fopen(fullpath, "rw+");
+	FOPEN_OR_ERR_RET(f, ret);
+
+	s = fgets(buf, sizeof(buf), f);
+	FOPS_OR_NULL_GOTO(s, out);
+
+	/* Check if current governor is performance */
+	if (strncmp(buf, POWER_GOVERNOR_PERF,
+			sizeof(POWER_GOVERNOR_PERF)) == 0) {
+		ret = 0;
+		POWER_DEBUG_TRACE("Power management governor of lcore %u is "
+				"already performance\n", pi->lcore_id);
+		goto out;
+	}
+	/* Save the original governor */
+	snprintf(pi->governor_ori, sizeof(pi->governor_ori), "%s", buf);
+
+	/* Write 'performance' to the governor */
+	val = fseek(f, 0, SEEK_SET);
+	FOPS_OR_ERR_GOTO(val, out);
+
+	val = fputs(POWER_GOVERNOR_PERF, f);
+	FOPS_OR_ERR_GOTO(val, out);
+
+	ret = 0;
+	RTE_LOG(INFO, POWER, "Power management governor of lcore %u has been "
+			"set to performance successfully\n", pi->lcore_id);
+out:
+	fclose(f);
+
+	return ret;
+}
+
+/**
+ * It is to check the governor and then set the original governor back if
+ * needed by writing the sys file.
+ */
+static int
+power_set_governor_original(struct pstate_power_info *pi)
+{
+	FILE *f;
+	int ret = -1;
+	char buf[BUFSIZ];
+	char fullpath[PATH_MAX];
+	char *s;
+	int val;
+
+	snprintf(fullpath, sizeof(fullpath), POWER_SYSFILE_GOVERNOR,
+			pi->lcore_id);
+	f = fopen(fullpath, "rw+");
+	FOPEN_OR_ERR_RET(f, ret);
+
+	s = fgets(buf, sizeof(buf), f);
+	FOPS_OR_NULL_GOTO(s, out);
+
+	/* Check if the governor to be set is the same as current */
+	if (strncmp(buf, pi->governor_ori, sizeof(pi->governor_ori)) == 0) {
+		ret = 0;
+		POWER_DEBUG_TRACE("Power management governor of lcore %u "
+				"has already been set to %s\n",
+				pi->lcore_id, pi->governor_ori);
+		goto out;
+	}
+
+	/* Write back the original governor */
+	val = fseek(f, 0, SEEK_SET);
+	FOPS_OR_ERR_GOTO(val, out);
+
+	val = fputs(pi->governor_ori, f);
+	FOPS_OR_ERR_GOTO(val, out);
+
+	ret = 0;
+	RTE_LOG(INFO, POWER, "Power management governor of lcore %u "
+			"has been set back to %s successfully\n",
+			pi->lcore_id, pi->governor_ori);
+out:
+	fclose(f);
+
+	return ret;
+}
+
+/**
+ * It is to get the available frequencies of the specific lcore by reading the
+ * sys file.
+ */
+static int
+power_get_available_freqs(struct pstate_power_info *pi)
+{
+	FILE *f_min, *f_max;
+	int ret = -1;
+	char *p_min, *p_max;
+	char buf_min[BUFSIZ];
+	char buf_max[BUFSIZ];
+	char fullpath_min[PATH_MAX];
+	char fullpath_max[PATH_MAX];
+	char *s_min, *s_max;
+	uint32_t sys_min_freq = 0, sys_max_freq = 0, base_max_freq = 0;
+	uint32_t i, num_freqs = 0;
+
+	snprintf(fullpath_max, sizeof(fullpath_max),
+			POWER_SYSFILE_BASE_MAX_FREQ,
+			pi->lcore_id);
+	snprintf(fullpath_min, sizeof(fullpath_min),
+			POWER_SYSFILE_BASE_MIN_FREQ,
+			pi->lcore_id);
+
+	f_min = fopen(fullpath_min, "r");
+	FOPEN_OR_ERR_RET(f_min, ret);
+
+	f_max = fopen(fullpath_max, "r");
+	FOPEN_OR_ERR_RET(f_max, ret);
+
+	s_min = fgets(buf_min, sizeof(buf_min), f_min);
+	FOPS_OR_NULL_GOTO(s_min, out);
+
+	s_max = fgets(buf_max, sizeof(buf_max), f_max);
+	FOPS_OR_NULL_GOTO(s_max, out);
+
+
+	/* Strip the line break if there is */
+	p_min = strchr(buf_min, '\n');
+	if (p_min != NULL)
+		*p_min = 0;
+
+	p_max = strchr(buf_max, '\n');
+	if (p_max != NULL)
+		*p_max = 0;
+
+	sys_min_freq = strtoul(buf_min, &p_min, POWER_CONVERT_TO_DECIMAL);
+	sys_max_freq = strtoul(buf_max, &p_max, POWER_CONVERT_TO_DECIMAL);
+
+	if (sys_max_freq < sys_min_freq)
+		goto out;
+
+	pi->sys_max_freq = sys_max_freq;
+
+	base_max_freq = pi->non_turbo_max_ratio * BUS_FREQ;
+
+	POWER_DEBUG_TRACE("sys min %u, sys max %u, base_max %u\n",
+			sys_min_freq,
+			sys_max_freq,
+			base_max_freq);
+
+	if (base_max_freq < sys_max_freq)
+		pi->turbo_available = 1;
+	else
+		pi->turbo_available = 0;
+
+	/* If turbo is available then there is one extra freq bucket
+	 * to store the sys max freq which value is base_max +1
+	 */
+	num_freqs = (base_max_freq - sys_min_freq) / BUS_FREQ + 1 +
+		pi->turbo_available;
+
+	/* Generate the freq bucket array.
+	 * If turbo is available the freq bucket[0] value is base_max +1
+	 * the bucket[1] is base_max, bucket[2] is base_max - BUS_FREQ
+	 * and so on.
+	 * If turbo is not available bucket[0] is base_max and so on
+	 */
+	for (i = 0, pi->nb_freqs = 0; i < num_freqs; i++) {
+		if ((i == 0) && pi->turbo_available)
+			pi->freqs[pi->nb_freqs++] = base_max_freq + 1;
+		else
+			pi->freqs[pi->nb_freqs++] =
+			base_max_freq - (i - pi->turbo_available) * BUS_FREQ;
+	}
+
+	ret = 0;
+
+	POWER_DEBUG_TRACE("%d frequency(s) of lcore %u are available\n",
+			num_freqs, pi->lcore_id);
+
+out:
+	fclose(f_min);
+	fclose(f_max);
+
+	return ret;
+}
+
+int
+power_pstate_cpufreq_init(unsigned int lcore_id)
+{
+	struct pstate_power_info *pi;
+
+	if (lcore_id >= RTE_MAX_LCORE) {
+		RTE_LOG(ERR, POWER, "Lcore id %u can not exceed %u\n",
+				lcore_id, RTE_MAX_LCORE - 1U);
+		return -1;
+	}
+
+	pi = &lcore_power_info[lcore_id];
+	if (rte_atomic32_cmpset(&(pi->state), POWER_IDLE, POWER_ONGOING)
+			== 0) {
+		RTE_LOG(INFO, POWER, "Power management of lcore %u is "
+				"in use\n", lcore_id);
+		return -1;
+	}
+
+	pi->lcore_id = lcore_id;
+	/* Check and set the governor */
+	if (power_set_governor_performance(pi) < 0) {
+		RTE_LOG(ERR, POWER, "Cannot set governor of lcore %u to "
+				"performance\n", lcore_id);
+		goto fail;
+	}
+	/* Init for setting lcore frequency */
+	if (power_init_for_setting_freq(pi) < 0) {
+		RTE_LOG(ERR, POWER, "Cannot init for setting frequency for "
+				"lcore %u\n", lcore_id);
+		goto fail;
+	}
+
+	/* Get the available frequencies */
+	if (power_get_available_freqs(pi) < 0) {
+		RTE_LOG(ERR, POWER, "Cannot get available frequencies of "
+				"lcore %u\n", lcore_id);
+		goto fail;
+	}
+
+
+	/* Set freq to max by default */
+	if (power_pstate_cpufreq_freq_max(lcore_id) < 0) {
+		RTE_LOG(ERR, POWER, "Cannot set frequency of lcore %u "
+				"to max\n", lcore_id);
+		goto fail;
+	}
+
+	RTE_LOG(INFO, POWER, "Initialized successfully for lcore %u "
+			"power management\n", lcore_id);
+	rte_atomic32_cmpset(&(pi->state), POWER_ONGOING, POWER_USED);
+
+	return 0;
+
+fail:
+	rte_atomic32_cmpset(&(pi->state), POWER_ONGOING, POWER_UNKNOWN);
+
+	return -1;
+}
+
+int
+power_pstate_cpufreq_exit(unsigned int lcore_id)
+{
+	struct pstate_power_info *pi;
+
+	if (lcore_id >= RTE_MAX_LCORE) {
+		RTE_LOG(ERR, POWER, "Lcore id %u can not exceeds %u\n",
+				lcore_id, RTE_MAX_LCORE - 1U);
+		return -1;
+	}
+	pi = &lcore_power_info[lcore_id];
+
+	if (rte_atomic32_cmpset(&(pi->state), POWER_USED, POWER_ONGOING)
+			== 0) {
+		RTE_LOG(INFO, POWER, "Power management of lcore %u is "
+				"not used\n", lcore_id);
+		return -1;
+	}
+
+	/* Close FD of setting freq */
+	fclose(pi->f_cur_min);
+	fclose(pi->f_cur_max);
+	pi->f_cur_min = NULL;
+	pi->f_cur_max = NULL;
+
+	/* Set the governor back to the original */
+	if (power_set_governor_original(pi) < 0) {
+		RTE_LOG(ERR, POWER, "Cannot set the governor of %u back "
+				"to the original\n", lcore_id);
+		goto fail;
+	}
+
+	RTE_LOG(INFO, POWER, "Power management of lcore %u has exited from "
+			"'performance' mode and been set back to the "
+			"original\n", lcore_id);
+	rte_atomic32_cmpset(&(pi->state), POWER_ONGOING, POWER_IDLE);
+
+	return 0;
+
+fail:
+	rte_atomic32_cmpset(&(pi->state), POWER_ONGOING, POWER_UNKNOWN);
+
+	return -1;
+}
+
+
+uint32_t
+power_pstate_cpufreq_freqs(unsigned int lcore_id, uint32_t *freqs, uint32_t num)
+{
+	struct pstate_power_info *pi;
+
+	if (lcore_id >= RTE_MAX_LCORE) {
+		RTE_LOG(ERR, POWER, "Invalid lcore ID\n");
+		return -1;
+	}
+
+	pi = &lcore_power_info[lcore_id];
+	if (num < pi->nb_freqs) {
+		RTE_LOG(ERR, POWER, "Buffer size is not enough\n");
+		return 0;
+	}
+	rte_memcpy(freqs, pi->freqs, pi->nb_freqs * sizeof(uint32_t));
+
+	return pi->nb_freqs;
+}
+
+uint32_t
+power_pstate_cpufreq_get_freq(unsigned int lcore_id)
+{
+	if (lcore_id >= RTE_MAX_LCORE) {
+		RTE_LOG(ERR, POWER, "Invalid lcore ID\n");
+		return RTE_POWER_INVALID_FREQ_INDEX;
+	}
+
+	return lcore_power_info[lcore_id].curr_idx;
+}
+
+
+int
+power_pstate_cpufreq_set_freq(unsigned int lcore_id, uint32_t index)
+{
+	if (lcore_id >= RTE_MAX_LCORE) {
+		RTE_LOG(ERR, POWER, "Invalid lcore ID\n");
+		return -1;
+	}
+
+	return set_freq_internal(&(lcore_power_info[lcore_id]), index);
+}
+
+int
+power_pstate_cpufreq_freq_up(unsigned int lcore_id)
+{
+	struct pstate_power_info *pi;
+
+	if (lcore_id >= RTE_MAX_LCORE) {
+		RTE_LOG(ERR, POWER, "Invalid lcore ID\n");
+		return -1;
+	}
+
+	pi = &lcore_power_info[lcore_id];
+	if (pi->curr_idx == 0)
+		return 0;
+
+	/* Frequencies in the array are from high to low. */
+	return set_freq_internal(pi, pi->curr_idx - 1);
+}
+
+int
+power_pstate_cpufreq_freq_down(unsigned int lcore_id)
+{
+	struct pstate_power_info *pi;
+
+	if (lcore_id >= RTE_MAX_LCORE) {
+		RTE_LOG(ERR, POWER, "Invalid lcore ID\n");
+		return -1;
+	}
+
+	pi = &lcore_power_info[lcore_id];
+	if (pi->curr_idx + 1 == pi->nb_freqs)
+		return 0;
+
+	/* Frequencies in the array are from high to low. */
+	return set_freq_internal(pi, pi->curr_idx + 1);
+}
+
+int
+power_pstate_cpufreq_freq_max(unsigned int lcore_id)
+{
+	if (lcore_id >= RTE_MAX_LCORE) {
+		RTE_LOG(ERR, POWER, "Invalid lcore ID\n");
+		return -1;
+	}
+
+	/* Frequencies in the array are from high to low. */
+	if (lcore_power_info[lcore_id].turbo_available) {
+		if (lcore_power_info[lcore_id].turbo_enable)
+			/* Set to Turbo */
+			return set_freq_internal(
+					&lcore_power_info[lcore_id], 0);
+		else
+			/* Set to max non-turbo */
+			return set_freq_internal(
+					&lcore_power_info[lcore_id], 1);
+	} else
+		return set_freq_internal(&lcore_power_info[lcore_id], 0);
+}
+
+
+int
+power_pstate_cpufreq_freq_min(unsigned int lcore_id)
+{
+	struct pstate_power_info *pi;
+
+	if (lcore_id >= RTE_MAX_LCORE) {
+		RTE_LOG(ERR, POWER, "Invalid lcore ID\n");
+		return -1;
+	}
+
+	pi = &lcore_power_info[lcore_id];
+
+	/* Frequencies in the array are from high to low. */
+	return set_freq_internal(pi, pi->nb_freqs - 1);
+}
+
+
+int
+power_pstate_turbo_status(unsigned int lcore_id)
+{
+	struct pstate_power_info *pi;
+
+	if (lcore_id >= RTE_MAX_LCORE) {
+		RTE_LOG(ERR, POWER, "Invalid lcore ID\n");
+		return -1;
+	}
+
+	pi = &lcore_power_info[lcore_id];
+
+	return pi->turbo_enable;
+}
+
+int
+power_pstate_enable_turbo(unsigned int lcore_id)
+{
+	struct pstate_power_info *pi;
+
+	if (lcore_id >= RTE_MAX_LCORE) {
+		RTE_LOG(ERR, POWER, "Invalid lcore ID\n");
+		return -1;
+	}
+
+	pi = &lcore_power_info[lcore_id];
+
+	if (pi->turbo_available)
+		pi->turbo_enable = 1;
+	else {
+		pi->turbo_enable = 0;
+		RTE_LOG(ERR, POWER,
+			"Failed to enable turbo on lcore %u\n",
+			lcore_id);
+			return -1;
+	}
+
+	return 0;
+}
+
+
+int
+power_pstate_disable_turbo(unsigned int lcore_id)
+{
+	struct pstate_power_info *pi;
+
+	if (lcore_id >= RTE_MAX_LCORE) {
+		RTE_LOG(ERR, POWER, "Invalid lcore ID\n");
+		return -1;
+	}
+
+	pi = &lcore_power_info[lcore_id];
+
+	pi->turbo_enable = 0;
+
+
+	return 0;
+}
+
+
+int power_pstate_get_capabilities(unsigned int lcore_id,
+		struct rte_power_core_capabilities *caps)
+{
+	struct pstate_power_info *pi;
+
+	if (lcore_id >= RTE_MAX_LCORE) {
+		RTE_LOG(ERR, POWER, "Invalid lcore ID\n");
+		return -1;
+	}
+	if (caps == NULL) {
+		RTE_LOG(ERR, POWER, "Invalid argument\n");
+		return -1;
+	}
+
+	pi = &lcore_power_info[lcore_id];
+	caps->capabilities = 0;
+	caps->turbo = !!(pi->turbo_available);
+
+	return 0;
+}
diff --git a/lib/librte_power/power_pstate_cpufreq.h b/lib/librte_power/power_pstate_cpufreq.h
new file mode 100644
index 0000000..b0019f5
--- /dev/null
+++ b/lib/librte_power/power_pstate_cpufreq.h
@@ -0,0 +1,218 @@ 
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright(c) 2018-2018 Intel Corporation
+ */
+
+#ifndef _POWER_PSTATE_CPUFREQ_H
+#define _POWER_PSTATE_CPUFREQ_H
+
+/**
+ * @file
+ * RTE Power Management via Intel Pstate driver
+ */
+
+#include <rte_common.h>
+#include <rte_byteorder.h>
+#include <rte_log.h>
+#include <rte_string_fns.h>
+#include "rte_power.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * Initialize power management for a specific lcore. It will check and set the
+ * governor to performance for the lcore, get the available frequencies, and
+ * prepare to set new lcore frequency.
+ *
+ * @param lcore_id
+ *  lcore id.
+ *
+ * @return
+ *  - 0 on success.
+ *  - Negative on error.
+ */
+int power_pstate_cpufreq_init(unsigned int lcore_id);
+
+/**
+ * Exit power management on a specific lcore. It will set the governor to which
+ * is before initialized.
+ *
+ * @param lcore_id
+ *  lcore id.
+ *
+ * @return
+ *  - 0 on success.
+ *  - Negative on error.
+ */
+int power_pstate_cpufreq_exit(unsigned int lcore_id);
+
+/**
+ * Get the available frequencies of a specific lcore. The return value will be
+ * the minimal one of the total number of available frequencies and the number
+ * of buffer. The index of available frequencies used in other interfaces
+ * should be in the range of 0 to this return value.
+ * It should be protected outside of this function for threadsafe.
+ *
+ * @param lcore_id
+ *  lcore id.
+ * @param freqs
+ *  The buffer array to save the frequencies.
+ * @param num
+ *  The number of frequencies to get.
+ *
+ * @return
+ *  The number of available frequencies.
+ */
+uint32_t power_pstate_cpufreq_freqs(unsigned int lcore_id, uint32_t *freqs,
+		uint32_t num);
+
+/**
+ * Return the current index of available frequencies of a specific lcore.
+ * It should be protected outside of this function for threadsafe.
+ *
+ * @param lcore_id
+ *  lcore id.
+ *
+ * @return
+ *  The current index of available frequencies.
+ *  If error, it will return 'RTE_POWER_INVALID_FREQ_INDEX = (~0)'.
+ */
+uint32_t power_pstate_cpufreq_get_freq(unsigned int lcore_id);
+
+/**
+ * Set the new frequency for a specific lcore by indicating the index of
+ * available frequencies.
+ * It should be protected outside of this function for threadsafe.
+ *
+ * @param lcore_id
+ *  lcore id.
+ * @param index
+ *  The index of available frequencies.
+ *
+ * @return
+ *  - 1 on success with frequency changed.
+ *  - 0 on success without frequency changed.
+ *  - Negative on error.
+ */
+int power_pstate_cpufreq_set_freq(unsigned int lcore_id, uint32_t index);
+
+/**
+ * Scale up the frequency of a specific lcore according to the available
+ * frequencies.
+ * It should be protected outside of this function for threadsafe.
+ *
+ * @param lcore_id
+ *  lcore id.
+ *
+ * @return
+ *  - 1 on success with frequency changed.
+ *  - 0 on success without frequency changed.
+ *  - Negative on error.
+ */
+int power_pstate_cpufreq_freq_up(unsigned int lcore_id);
+
+/**
+ * Scale down the frequency of a specific lcore according to the available
+ * frequencies.
+ * It should be protected outside of this function for threadsafe.
+ *
+ * @param lcore_id
+ *  lcore id.
+ *
+ * @return
+ *  - 1 on success with frequency changed.
+ *  - 0 on success without frequency changed.
+ *  - Negative on error.
+ */
+int power_pstate_cpufreq_freq_down(unsigned int lcore_id);
+
+/**
+ * Scale up the frequency of a specific lcore to the highest according to the
+ * available frequencies.
+ * It should be protected outside of this function for threadsafe.
+ *
+ * @param lcore_id
+ *  lcore id.
+ *
+ * @return
+ *  - 1 on success with frequency changed.
+ *  - 0 on success without frequency changed.
+ *  - Negative on error.
+ */
+int power_pstate_cpufreq_freq_max(unsigned int lcore_id);
+
+/**
+ * Scale down the frequency of a specific lcore to the lowest according to the
+ * available frequencies.
+ * It should be protected outside of this function for threadsafe.
+ *
+ * @param lcore_id
+ *  lcore id.
+ *
+ * @return
+ *  - 1 on success with frequency changed.
+ *  - 0 on success without frequency changed.
+ *  - Negative on error.
+ */
+int power_pstate_cpufreq_freq_min(unsigned int lcore_id);
+
+/**
+ * Get the turbo status of a specific lcore.
+ * It should be protected outside of this function for threadsafe.
+ *
+ * @param lcore_id
+ *  lcore id.
+ *
+ * @return
+ *  - 1 Turbo Boost is enabled on this lcore.
+ *  - 0 Turbo Boost is disabled on this lcore.
+ *  - Negative on error.
+ */
+int power_pstate_turbo_status(unsigned int lcore_id);
+
+/**
+ * Enable Turbo Boost on a specific lcore.
+ * It should be protected outside of this function for threadsafe.
+ *
+ * @param lcore_id
+ *  lcore id.
+ *
+ * @return
+ *  - 0 Turbo Boost is enabled successfully on this lcore.
+ *  - Negative on error.
+ */
+int power_pstate_enable_turbo(unsigned int lcore_id);
+
+/**
+ * Disable Turbo Boost on a specific lcore.
+ * It should be protected outside of this function for threadsafe.
+ *
+ * @param lcore_id
+ *  lcore id.
+ *
+ * @return
+ *  - 0 Turbo Boost disabled successfully on this lcore.
+ *  - Negative on error.
+ */
+int power_pstate_disable_turbo(unsigned int lcore_id);
+
+/**
+ * Returns power capabilities for a specific lcore.
+ *
+ * @param lcore_id
+ *  lcore id.
+ * @param caps
+ *  pointer to rte_power_core_capabilities object.
+ *
+ * @return
+ *  - 0 on success.
+ *  - Negative on error.
+ */
+int power_pstate_get_capabilities(unsigned int lcore_id,
+		struct rte_power_core_capabilities *caps);
+#ifdef __cplusplus
+}
+#endif
+
+#endif
diff --git a/lib/librte_power/rte_power.c b/lib/librte_power/rte_power.c
index 208b791..a05fbef 100644
--- a/lib/librte_power/rte_power.c
+++ b/lib/librte_power/rte_power.c
@@ -7,6 +7,7 @@ 
 #include "rte_power.h"
 #include "power_acpi_cpufreq.h"
 #include "power_kvm_vm.h"
+#include "power_pstate_cpufreq.h"
 #include "power_common.h"
 
 enum power_management_env global_default_env = PM_ENV_NOT_SET;
@@ -56,6 +57,19 @@  rte_power_set_env(enum power_management_env env)
 		rte_power_freq_enable_turbo = power_kvm_vm_enable_turbo;
 		rte_power_freq_disable_turbo = power_kvm_vm_disable_turbo;
 		rte_power_get_capabilities = power_kvm_vm_get_capabilities;
+	} else if (env == PM_ENV_PSTATE_CPUFREQ) {
+		rte_power_freqs = power_pstate_cpufreq_freqs;
+		rte_power_get_freq = power_pstate_cpufreq_get_freq;
+		rte_power_set_freq = power_pstate_cpufreq_set_freq;
+		rte_power_freq_up = power_pstate_cpufreq_freq_up;
+		rte_power_freq_down = power_pstate_cpufreq_freq_down;
+		rte_power_freq_min = power_pstate_cpufreq_freq_min;
+		rte_power_freq_max = power_pstate_cpufreq_freq_max;
+		rte_power_turbo_status = power_pstate_turbo_status;
+		rte_power_freq_enable_turbo = power_pstate_enable_turbo;
+		rte_power_freq_disable_turbo = power_pstate_disable_turbo;
+		rte_power_get_capabilities = power_pstate_get_capabilities;
+
 	} else {
 		RTE_LOG(ERR, POWER, "Invalid Power Management Environment(%d) set\n",
 				env);
@@ -64,7 +78,6 @@  rte_power_set_env(enum power_management_env env)
 	}
 	global_default_env = env;
 	return 0;
-
 }
 
 void
@@ -84,21 +97,32 @@  rte_power_init(unsigned int lcore_id)
 {
 	int ret = -1;
 
-	if (global_default_env == PM_ENV_ACPI_CPUFREQ) {
+	switch (global_default_env) {
+	case PM_ENV_ACPI_CPUFREQ:
 		return power_acpi_cpufreq_init(lcore_id);
-	}
-	if (global_default_env == PM_ENV_KVM_VM) {
+	case PM_ENV_KVM_VM:
 		return power_kvm_vm_init(lcore_id);
+	case PM_ENV_PSTATE_CPUFREQ:
+		return power_pstate_cpufreq_init(lcore_id);
+	default:
+		RTE_LOG(INFO, POWER, "Env isn't set yet!\n");
 	}
+
 	/* Auto detect Environment */
-	RTE_LOG(INFO, POWER, "Attempting to initialise ACPI cpufreq power "
-			"management...\n");
+	RTE_LOG(INFO, POWER, "Attempting to initialise ACPI cpufreq power management...\n");
 	ret = power_acpi_cpufreq_init(lcore_id);
 	if (ret == 0) {
 		rte_power_set_env(PM_ENV_ACPI_CPUFREQ);
 		goto out;
 	}
 
+	RTE_LOG(INFO, POWER, "Attempting to initialise PSTAT power management...\n");
+	ret = power_pstate_cpufreq_init(lcore_id);
+	if (ret == 0) {
+		rte_power_set_env(PM_ENV_PSTATE_CPUFREQ);
+		goto out;
+	}
+
 	RTE_LOG(INFO, POWER, "Attempting to initialise VM power management...\n");
 	ret = power_kvm_vm_init(lcore_id);
 	if (ret == 0) {
@@ -114,13 +138,17 @@  rte_power_init(unsigned int lcore_id)
 int
 rte_power_exit(unsigned int lcore_id)
 {
-	if (global_default_env == PM_ENV_ACPI_CPUFREQ)
+	switch (global_default_env) {
+	case PM_ENV_ACPI_CPUFREQ:
 		return power_acpi_cpufreq_exit(lcore_id);
-	if (global_default_env == PM_ENV_KVM_VM)
+	case PM_ENV_KVM_VM:
 		return power_kvm_vm_exit(lcore_id);
+	case PM_ENV_PSTATE_CPUFREQ:
+		return power_pstate_cpufreq_exit(lcore_id);
+	default:
+		RTE_LOG(ERR, POWER, "Environment has not been set, unable to exit gracefully\n");
 
-	RTE_LOG(ERR, POWER, "Environment has not been set, unable to exit "
-				"gracefully\n");
+	}
 	return -1;
 
 }
diff --git a/lib/librte_power/rte_power.h b/lib/librte_power/rte_power.h
index d70bc0b..c5e8f6b 100644
--- a/lib/librte_power/rte_power.h
+++ b/lib/librte_power/rte_power.h
@@ -20,7 +20,8 @@  extern "C" {
 #endif
 
 /* Power Management Environment State */
-enum power_management_env {PM_ENV_NOT_SET, PM_ENV_ACPI_CPUFREQ, PM_ENV_KVM_VM};
+enum power_management_env {PM_ENV_NOT_SET, PM_ENV_ACPI_CPUFREQ, PM_ENV_KVM_VM,
+		PM_ENV_PSTATE_CPUFREQ};
 
 /**
  * Set the default power management implementation. If this is not called prior