/*-
 *   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 <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 <rte_memcpy.h>
#include <rte_atomic.h>

#include "rte_power.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 STR_SIZE     1024
#define POWER_CONVERT_TO_DECIMAL 10

#define POWER_GOVERNOR_USERSPACE "userspace"
#define POWER_SYSFILE_GOVERNOR   \
	"/sys/devices/system/cpu/cpu%u/cpufreq/scaling_governor"
#define POWER_SYSFILE_AVAIL_FREQ \
	"/sys/devices/system/cpu/cpu%u/cpufreq/scaling_available_frequencies"
#define POWER_SYSFILE_SETSPEED   \
	"/sys/devices/system/cpu/cpu%u/cpufreq/scaling_setspeed"

enum power_state {
	POWER_IDLE = 0,
	POWER_ONGOING,
	POWER_USED,
	POWER_UNKNOWN
};

/**
 * Power info per lcore.
 */
struct rte_power_info {
	unsigned lcore_id;                   /**< Logical core id */
	uint32_t freqs[RTE_MAX_LCORE_FREQS]; /**< Frequency array */
	uint32_t nb_freqs;                   /**< number of available freqs */
	FILE *f;                             /**< FD of scaling_setspeed */
	char governor_ori[32];               /**< Original governor name */
	uint32_t curr_idx;                   /**< Freq index in freqs array */
	volatile uint32_t state;             /**< Power in use state */
} __rte_cache_aligned;

static struct rte_power_info lcore_power_info[RTE_MAX_LCORE];

/**
 * It is to set specific freq for specific logical core, according to the index
 * of supported frequencies.
 */
static int
set_freq_internal(struct rte_power_info *pi, uint32_t idx)
{
	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;

	POWER_DEBUG_TRACE("Freqency[%u] %u to be set for lcore %u\n",
				idx, pi->freqs[idx], pi->lcore_id);
	if (fseek(pi->f, 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 (fprintf(pi->f, "%u", pi->freqs[idx]) < 0) {
		RTE_LOG(ERR, POWER, "Fail to write new frequency for "
					"lcore %u\n", pi->lcore_id);
		return -1;
	}
	fflush(pi->f);
	pi->curr_idx = idx;

	return 1;
}

/**
 * It is to check the current scaling governor by reading sys file, and then
 * set it into 'userspace' if it is not by writing the sys file. The original
 * governor will be saved for rolling back.
 */
static int
power_set_governor_userspace(struct rte_power_info *pi)
{
	FILE *f;
	int ret = -1;
	char buf[BUFSIZ];
	char fullpath[PATH_MAX];
	char *s;
	int val;

	rte_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 userspace */
	if (strncmp(buf, POWER_GOVERNOR_USERSPACE,
		sizeof(POWER_GOVERNOR_USERSPACE)) == 0) {
		ret = 0;
		POWER_DEBUG_TRACE("Power management governor of lcore %u is "
					"already userspace\n", pi->lcore_id);
		goto out;
	}
	/* Save the original governor */
	rte_snprintf(pi->governor_ori, sizeof(pi->governor_ori), "%s", buf);

	/* Write 'userspace' to the governor */
	val = fseek(f, 0, SEEK_SET);
	FOPS_OR_ERR_GOTO(val, out);

	val = fputs(POWER_GOVERNOR_USERSPACE, f);
	FOPS_OR_ERR_GOTO(val, out);

	ret = 0;
	RTE_LOG(INFO, POWER, "Power management governor of lcore %u has been "
			"set to user space successfully\n", pi->lcore_id);
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 rte_power_info *pi)
{
	FILE *f;
	int ret = -1, i, count;
	char *p;
	char buf[BUFSIZ];
	char fullpath[PATH_MAX];
	char *freqs[RTE_MAX_LCORE_FREQS];
	char *s;

	rte_snprintf(fullpath, sizeof(fullpath), POWER_SYSFILE_AVAIL_FREQ,
								pi->lcore_id);
	f = fopen(fullpath, "r");
	FOPEN_OR_ERR_RET(f, ret);

	s = fgets(buf, sizeof(buf), f);
	FOPS_OR_NULL_GOTO(s, out);

	/* Strip the line break if there is */
	p = strchr(buf, '\n');
	if (p != NULL)
		*p = 0;

	/* Split string into at most RTE_MAX_LCORE_FREQS frequencies */
	count = rte_strsplit(buf, sizeof(buf), freqs,
				RTE_MAX_LCORE_FREQS, ' ');
	if (count <= 0) {
		RTE_LOG(ERR, POWER, "No available frequency in "
			""POWER_SYSFILE_AVAIL_FREQ"\n", pi->lcore_id);
		goto out;
	}
	if (count >= RTE_MAX_LCORE_FREQS) {
		RTE_LOG(ERR, POWER, "Too many available frequencies : %d\n",
								count);
		goto out;
	}

	/* Store the available frequncies into power context */
	for (i = 0, pi->nb_freqs = 0; i < count; i++) {
		POWER_DEBUG_TRACE("Lcore %u frequency[%d]: %s\n", pi->lcore_id,
								i, freqs[i]);
		pi->freqs[pi->nb_freqs++] = strtoul(freqs[i], &p,
					POWER_CONVERT_TO_DECIMAL);
	}

	ret = 0;
	POWER_DEBUG_TRACE("%d frequencie(s) of lcore %u are available\n",
						count, pi->lcore_id);
out:
	fclose(f);

	return ret;
}

/**
 * It is to fopen the sys file for the future setting the lcore frequency.
 */
static int
power_init_for_setting_freq(struct rte_power_info *pi)
{
	FILE *f;
	char fullpath[PATH_MAX];
	char buf[BUFSIZ];
	uint32_t i, freq;
	char *s;

	rte_snprintf(fullpath, sizeof(fullpath), POWER_SYSFILE_SETSPEED,
							pi->lcore_id);
	f = fopen(fullpath, "rw+");
	FOPEN_OR_ERR_RET(f, -1);

	s = fgets(buf, sizeof(buf), f);
	FOPS_OR_NULL_GOTO(s, out);

	freq = strtoul(buf, NULL, POWER_CONVERT_TO_DECIMAL);
	for (i = 0; i < pi->nb_freqs; i++) {
		if (freq == pi->freqs[i]) {
			pi->curr_idx = i;
			pi->f = f;
			return 0;
		}
	}

out:
	fclose(f);

	return -1;
}

int
rte_power_init(unsigned lcore_id)
{
	struct rte_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_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_userspace(pi) < 0) {
		RTE_LOG(ERR, POWER, "Cannot set governor of lcore %u to "
						"userspace\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;
	}

	/* 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;
	}

	/* Set freq to max by default */
	if (rte_power_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 manamgement\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;
}

/**
 * It is to check the governor and then set the original governor back if
 * needed by writing the the sys file.
 */
static int
power_set_governor_original(struct rte_power_info *pi)
{
	FILE *f;
	int ret = -1;
	char buf[BUFSIZ];
	char fullpath[PATH_MAX];
	char *s;
	int val;

	rte_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 manamgement governor of lcore %u "
				"has been set back to %s successfully\n",
					pi->lcore_id, pi->governor_ori);
out:
	fclose(f);

	return ret;
}

int
rte_power_exit(unsigned lcore_id)
{
	struct rte_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);
	pi->f = 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 "
				"'userspace' 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
rte_power_freqs(unsigned lcore_id, uint32_t *freqs, uint32_t num)
{
	struct rte_power_info *pi;

	if (lcore_id >= RTE_MAX_LCORE || !freqs) {
		RTE_LOG(ERR, POWER, "Invalid input parameter\n");
		return 0;
	}

	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
rte_power_get_freq(unsigned 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
rte_power_set_freq(unsigned 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
rte_power_freq_down(unsigned lcore_id)
{
	struct rte_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
rte_power_freq_up(unsigned lcore_id)
{
	struct rte_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
rte_power_freq_max(unsigned 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. */
	return set_freq_internal(&lcore_power_info[lcore_id], 0);
}
 
int
rte_power_freq_min(unsigned lcore_id)
{
	struct rte_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);
}