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/*-
 *   BSD LICENSE
 *
 *   Copyright(c) 2010-2014 Intel Corporation. All rights reserved.
 *   All rights reserved.
 *
 *   Redistribution and use in source and binary forms, with or without
 *   modification, are permitted provided that the following conditions
 *   are met:
 *
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in
 *       the documentation and/or other materials provided with the
 *       distribution.
 *     * Neither the name of Intel Corporation nor the names of its
 *       contributors may be used to endorse or promote products derived
 *       from this software without specific prior written permission.
 *
 *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <inttypes.h>
#include <sys/un.h>
#include <fcntl.h>
#include <unistd.h>
#include <dirent.h>
#include <errno.h>

#include <sys/types.h>

#include <rte_config.h>
#include <rte_log.h>
#include <rte_power.h>
#include <rte_spinlock.h>

#include "power_manager.h"

#define RTE_LOGTYPE_POWER_MANAGER RTE_LOGTYPE_USER1

#define POWER_SCALE_CORE(DIRECTION, core_num , ret) do { \
	if (core_num >= POWER_MGR_MAX_CPUS) \
		return -1; \
	if (!(global_enabled_cpus & (1ULL << core_num))) \
		return -1; \
	rte_spinlock_lock(&global_core_freq_info[core_num].power_sl); \
	ret = rte_power_freq_##DIRECTION(core_num); \
	rte_spinlock_unlock(&global_core_freq_info[core_num].power_sl); \
} while (0)

#define POWER_SCALE_MASK(DIRECTION, core_mask, ret) do { \
	int i; \
	for (i = 0; core_mask; core_mask &= ~(1 << i++)) { \
		if ((core_mask >> i) & 1) { \
			if (!(global_enabled_cpus & (1ULL << i))) \
				continue; \
			rte_spinlock_lock(&global_core_freq_info[i].power_sl); \
			if (rte_power_freq_##DIRECTION(i) != 1) \
				ret = -1; \
			rte_spinlock_unlock(&global_core_freq_info[i].power_sl); \
		} \
	} \
} while (0)

struct freq_info {
	rte_spinlock_t power_sl;
	uint32_t freqs[RTE_MAX_LCORE_FREQS];
	unsigned num_freqs;
} __rte_cache_aligned;

static struct freq_info global_core_freq_info[POWER_MGR_MAX_CPUS];

static uint64_t global_enabled_cpus;

#define SYSFS_CPU_PATH "/sys/devices/system/cpu/cpu%u/topology/core_id"

static unsigned
set_host_cpus_mask(void)
{
	char path[PATH_MAX];
	unsigned i;
	unsigned num_cpus = 0;

	for (i = 0; i < POWER_MGR_MAX_CPUS; i++) {
		snprintf(path, sizeof(path), SYSFS_CPU_PATH, i);
		if (access(path, F_OK) == 0) {
			global_enabled_cpus |= 1ULL << i;
			num_cpus++;
		} else
			return num_cpus;
	}
	return num_cpus;
}

int
power_manager_init(void)
{
	unsigned i, num_cpus;
	uint64_t cpu_mask;
	int ret = 0;

	num_cpus = set_host_cpus_mask();
	if (num_cpus == 0) {
		RTE_LOG(ERR, POWER_MANAGER, "Unable to detected host CPUs, please "
			"ensure that sufficient privileges exist to inspect sysfs\n");
		return -1;
	}
	rte_power_set_env(PM_ENV_ACPI_CPUFREQ);
	cpu_mask = global_enabled_cpus;
	for (i = 0; cpu_mask; cpu_mask &= ~(1 << i++)) {
		if (rte_power_init(i) < 0 || rte_power_freqs(i,
				global_core_freq_info[i].freqs,
				RTE_MAX_LCORE_FREQS) == 0) {
			RTE_LOG(ERR, POWER_MANAGER, "Unable to initialize power manager "
					"for core %u\n", i);
			global_enabled_cpus &= ~(1 << i);
			num_cpus--;
			ret = -1;
		}
		rte_spinlock_init(&global_core_freq_info[i].power_sl);
	}
	RTE_LOG(INFO, POWER_MANAGER, "Detected %u host CPUs , enabled core mask:"
					" 0x%"PRIx64"\n", num_cpus, global_enabled_cpus);
	return ret;

}

uint32_t
power_manager_get_current_frequency(unsigned core_num)
{
	uint32_t freq, index;

	if (core_num >= POWER_MGR_MAX_CPUS) {
		RTE_LOG(ERR, POWER_MANAGER, "Core(%u) is out of range 0...%d\n",
				core_num, POWER_MGR_MAX_CPUS-1);
		return -1;
	}
	if (!(global_enabled_cpus & (1ULL << core_num)))
		return 0;

	rte_spinlock_lock(&global_core_freq_info[core_num].power_sl);
	index = rte_power_get_freq(core_num);
	rte_spinlock_unlock(&global_core_freq_info[core_num].power_sl);
	if (index >= POWER_MGR_MAX_CPUS)
		freq = 0;
	else
		freq = global_core_freq_info[core_num].freqs[index];

	return freq;
}

int
power_manager_exit(void)
{
	unsigned int i;
	int ret = 0;

	for (i = 0; global_enabled_cpus; global_enabled_cpus &= ~(1 << i++)) {
		if (rte_power_exit(i) < 0) {
			RTE_LOG(ERR, POWER_MANAGER, "Unable to shutdown power manager "
					"for core %u\n", i);
			ret = -1;
		}
	}
	global_enabled_cpus = 0;
	return ret;
}

int
power_manager_scale_mask_up(uint64_t core_mask)
{
	int ret = 0;

	POWER_SCALE_MASK(up, core_mask, ret);
	return ret;
}

int
power_manager_scale_mask_down(uint64_t core_mask)
{
	int ret = 0;

	POWER_SCALE_MASK(down, core_mask, ret);
	return ret;
}

int
power_manager_scale_mask_min(uint64_t core_mask)
{
	int ret = 0;

	POWER_SCALE_MASK(min, core_mask, ret);
	return ret;
}

int
power_manager_scale_mask_max(uint64_t core_mask)
{
	int ret = 0;

	POWER_SCALE_MASK(max, core_mask, ret);
	return ret;
}

int
power_manager_scale_core_up(unsigned core_num)
{
	int ret = 0;

	POWER_SCALE_CORE(up, core_num, ret);
	return ret;
}

int
power_manager_scale_core_down(unsigned core_num)
{
	int ret = 0;

	POWER_SCALE_CORE(down, core_num, ret);
	return ret;
}

int
power_manager_scale_core_min(unsigned core_num)
{
	int ret = 0;

	POWER_SCALE_CORE(min, core_num, ret);
	return ret;
}

int
power_manager_scale_core_max(unsigned core_num)
{
	int ret = 0;

	POWER_SCALE_CORE(max, core_num, ret);
	return ret;
}