// SPDX-License-Identifier: GPL-2.0-only
/*
 * linux/drivers/cpufreq/freq_table.c
 *
 * Copyright (C) 2002 - 2003 Dominik Brodowski
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/cpufreq.h>
#include <linux/module.h>

/*********************************************************************
 *                     FREQUENCY TABLE HELPERS                       *
 *********************************************************************/

static bool policy_has_boost_freq(struct cpufreq_policy *policy)
{
        struct cpufreq_frequency_table *pos, *table = policy->freq_table;

        if (!table)
                return false;

        cpufreq_for_each_valid_entry(pos, table)
                if (pos->flags & CPUFREQ_BOOST_FREQ)
                        return true;

        return false;
}

int cpufreq_frequency_table_cpuinfo(struct cpufreq_policy *policy)
{
        struct cpufreq_frequency_table *pos, *table = policy->freq_table;
        unsigned int min_freq = ~0;
        unsigned int max_freq = 0;
        unsigned int freq, i;

        cpufreq_for_each_valid_entry_idx(pos, table, i) {
                freq = pos->frequency;

                if ((!cpufreq_boost_enabled() || !policy->boost_enabled)
                    && (pos->flags & CPUFREQ_BOOST_FREQ))
                        continue;

                pr_debug("table entry %u: %u kHz\n", i, freq);
                if (freq < min_freq)
                        min_freq = freq;
                if (freq > max_freq)
                        max_freq = freq;
        }

        policy->min = policy->cpuinfo.min_freq = min_freq;
        policy->max = max_freq;
        /*
         * If the driver has set its own cpuinfo.max_freq above max_freq, leave
         * it as is.
         */
        if (policy->cpuinfo.max_freq < max_freq)
                policy->max = policy->cpuinfo.max_freq = max_freq;

        if (policy->min == ~0)
                return -EINVAL;
        else
                return 0;
}

int cpufreq_frequency_table_verify(struct cpufreq_policy_data *policy)
{
        struct cpufreq_frequency_table *pos, *table = policy->freq_table;
        unsigned int freq, prev_smaller = 0;
        bool found = false;

        pr_debug("request for verification of policy (%u - %u kHz) for cpu %u\n",
                                        policy->min, policy->max, policy->cpu);

        cpufreq_verify_within_cpu_limits(policy);

        cpufreq_for_each_valid_entry(pos, table) {
                freq = pos->frequency;

                if ((freq >= policy->min) && (freq <= policy->max)) {
                        found = true;
                        break;
                }

                if ((prev_smaller < freq) && (freq <= policy->max))
                        prev_smaller = freq;
        }

        if (!found) {
                policy->max = prev_smaller;
                cpufreq_verify_within_cpu_limits(policy);
        }

        pr_debug("verification lead to (%u - %u kHz) for cpu %u\n",
                                policy->min, policy->max, policy->cpu);

        return 0;
}
EXPORT_SYMBOL_GPL(cpufreq_frequency_table_verify);

/*
 * Generic routine to verify policy & frequency table, requires driver to set
 * policy->freq_table prior to it.
 */
int cpufreq_generic_frequency_table_verify(struct cpufreq_policy_data *policy)
{
        if (!policy->freq_table)
                return -ENODEV;

        return cpufreq_frequency_table_verify(policy);
}
EXPORT_SYMBOL_GPL(cpufreq_generic_frequency_table_verify);

int cpufreq_table_index_unsorted(struct cpufreq_policy *policy,
                                 unsigned int target_freq, unsigned int min,
                                 unsigned int max, unsigned int relation)
{
        struct cpufreq_frequency_table optimal = {
                .driver_data = ~0,
                .frequency = 0,
        };
        struct cpufreq_frequency_table suboptimal = {
                .driver_data = ~0,
                .frequency = 0,
        };
        struct cpufreq_frequency_table *pos;
        struct cpufreq_frequency_table *table = policy->freq_table;
        unsigned int freq, diff, i;
        int index;

        pr_debug("request for target %u kHz (relation: %u) for cpu %u\n",
                                        target_freq, relation, policy->cpu);

        switch (relation) {
        case CPUFREQ_RELATION_H:
                suboptimal.frequency = ~0;
                break;
        case CPUFREQ_RELATION_L:
        case CPUFREQ_RELATION_C:
                optimal.frequency = ~0;
                break;
        }

        cpufreq_for_each_valid_entry_idx(pos, table, i) {
                freq = pos->frequency;

                if (freq < min || freq > max)
                        continue;
                if (freq == target_freq) {
                        optimal.driver_data = i;
                        break;
                }
                switch (relation) {
                case CPUFREQ_RELATION_H:
                        if (freq < target_freq) {
                                if (freq >= optimal.frequency) {
                                        optimal.frequency = freq;
                                        optimal.driver_data = i;
                                }
                        } else {
                                if (freq <= suboptimal.frequency) {
                                        suboptimal.frequency = freq;
                                        suboptimal.driver_data = i;
                                }
                        }
                        break;
                case CPUFREQ_RELATION_L:
                        if (freq > target_freq) {
                                if (freq <= optimal.frequency) {
                                        optimal.frequency = freq;
                                        optimal.driver_data = i;
                                }
                        } else {
                                if (freq >= suboptimal.frequency) {
                                        suboptimal.frequency = freq;
                                        suboptimal.driver_data = i;
                                }
                        }
                        break;
                case CPUFREQ_RELATION_C:
                        diff = abs(freq - target_freq);
                        if (diff < optimal.frequency ||
                            (diff == optimal.frequency &&
                             freq > table[optimal.driver_data].frequency)) {
                                optimal.frequency = diff;
                                optimal.driver_data = i;
                        }
                        break;
                }
        }
        if (optimal.driver_data > i) {
                if (suboptimal.driver_data > i) {
                        WARN(1, "Invalid frequency table: %u\n", policy->cpu);
                        return 0;
                }

                index = suboptimal.driver_data;
        } else
                index = optimal.driver_data;

        pr_debug("target index is %u, freq is:%u kHz\n", index,
                 table[index].frequency);
        return index;
}
EXPORT_SYMBOL_GPL(cpufreq_table_index_unsorted);

int cpufreq_frequency_table_get_index(struct cpufreq_policy *policy,
                unsigned int freq)
{
        struct cpufreq_frequency_table *pos, *table = policy->freq_table;
        int idx;

        if (unlikely(!table)) {
                pr_debug("%s: Unable to find frequency table\n", __func__);
                return -ENOENT;
        }

        cpufreq_for_each_valid_entry_idx(pos, table, idx)
                if (pos->frequency == freq)
                        return idx;

        return -EINVAL;
}
EXPORT_SYMBOL_GPL(cpufreq_frequency_table_get_index);

/*
 * show_available_freqs - show available frequencies for the specified CPU
 */
static ssize_t show_available_freqs(struct cpufreq_policy *policy, char *buf,
                                    bool show_boost)
{
        ssize_t count = 0;
        struct cpufreq_frequency_table *pos, *table = policy->freq_table;

        if (!table)
                return -ENODEV;

        cpufreq_for_each_valid_entry(pos, table) {
                /*
                 * show_boost = true and driver_data = BOOST freq
                 * display BOOST freqs
                 *
                 * show_boost = false and driver_data = BOOST freq
                 * show_boost = true and driver_data != BOOST freq
                 * continue - do not display anything
                 *
                 * show_boost = false and driver_data != BOOST freq
                 * display NON BOOST freqs
                 */
                if (show_boost ^ (pos->flags & CPUFREQ_BOOST_FREQ))
                        continue;

                count += sprintf(&buf[count], "%u ", pos->frequency);
        }
        count += sprintf(&buf[count], "\n");

        return count;

}

#define cpufreq_attr_available_freq(_name)        \
struct freq_attr cpufreq_freq_attr_##_name##_freqs =     \
__ATTR_RO(_name##_frequencies)

/*
 * scaling_available_frequencies_show - show available normal frequencies for
 * the specified CPU
 */
static ssize_t scaling_available_frequencies_show(struct cpufreq_policy *policy,
                                                  char *buf)
{
        return show_available_freqs(policy, buf, false);
}
cpufreq_attr_available_freq(scaling_available);

/*
 * scaling_boost_frequencies_show - show available boost frequencies for
 * the specified CPU
 */
static ssize_t scaling_boost_frequencies_show(struct cpufreq_policy *policy,
                                              char *buf)
{
        return show_available_freqs(policy, buf, true);
}
cpufreq_attr_available_freq(scaling_boost);

static int set_freq_table_sorted(struct cpufreq_policy *policy)
{
        struct cpufreq_frequency_table *pos, *table = policy->freq_table;
        struct cpufreq_frequency_table *prev = NULL;
        int ascending = 0;

        policy->freq_table_sorted = CPUFREQ_TABLE_UNSORTED;

        cpufreq_for_each_valid_entry(pos, table) {
                if (!prev) {
                        prev = pos;
                        continue;
                }

                if (pos->frequency == prev->frequency) {
                        pr_warn("Duplicate freq-table entries: %u\n",
                                pos->frequency);
                        return -EINVAL;
                }

                /* Frequency increased from prev to pos */
                if (pos->frequency > prev->frequency) {
                        /* But frequency was decreasing earlier */
                        if (ascending < 0) {
                                pr_debug("Freq table is unsorted\n");
                                return 0;
                        }

                        ascending++;
                } else {
                        /* Frequency decreased from prev to pos */

                        /* But frequency was increasing earlier */
                        if (ascending > 0) {
                                pr_debug("Freq table is unsorted\n");
                                return 0;
                        }

                        ascending--;
                }

                prev = pos;
        }

        if (ascending > 0)
                policy->freq_table_sorted = CPUFREQ_TABLE_SORTED_ASCENDING;
        else
                policy->freq_table_sorted = CPUFREQ_TABLE_SORTED_DESCENDING;

        pr_debug("Freq table is sorted in %s order\n",
                 ascending > 0 ? "ascending" : "descending");

        return 0;
}

int cpufreq_table_validate_and_sort(struct cpufreq_policy *policy)
{
        int ret;

        if (!policy->freq_table) {
                /* Freq table must be passed by drivers with target_index() */
                if (has_target_index())
                        return -EINVAL;

                return 0;
        }

        ret = cpufreq_frequency_table_cpuinfo(policy);
        if (ret)
                return ret;

        /* Driver's may have set this field already */
        if (policy_has_boost_freq(policy))
                policy->boost_supported = true;

        if (policy->freq_table_sorted == CPUFREQ_TABLE_SORTED_ASCENDING ||
            policy->freq_table_sorted == CPUFREQ_TABLE_SORTED_DESCENDING)
                return 0;

        return set_freq_table_sorted(policy);
}

MODULE_AUTHOR("Dominik Brodowski <linux@brodo.de>");
MODULE_DESCRIPTION("CPUfreq frequency table helpers");