/*
 * Generic OPP helper interface for CPU device
 *
 * Copyright (C) 2009-2014 Texas Instruments Incorporated.
 *      Nishanth Menon
 *      Romit Dasgupta
 *      Kevin Hilman
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/cpu.h>
#include <linux/cpufreq.h>
#include <linux/err.h>
#include <linux/errno.h>
#include <linux/export.h>
#include <linux/slab.h>

#include "opp.h"

#ifdef CONFIG_CPU_FREQ

/**
 * dev_pm_opp_init_cpufreq_table() - create a cpufreq table for a device
 * @dev:        device for which we do this operation
 * @table:      Cpufreq table returned back to caller
 *
 * Generate a cpufreq table for a provided device- this assumes that the
 * opp table is already initialized and ready for usage.
 *
 * This function allocates required memory for the cpufreq table. It is
 * expected that the caller does the required maintenance such as freeing
 * the table as required.
 *
 * Returns -EINVAL for bad pointers, -ENODEV if the device is not found, -ENOMEM
 * if no memory available for the operation (table is not populated), returns 0
 * if successful and table is populated.
 *
 * WARNING: It is  important for the callers to ensure refreshing their copy of
 * the table if any of the mentioned functions have been invoked in the interim.
 */
int dev_pm_opp_init_cpufreq_table(struct device *dev,
                                  struct cpufreq_frequency_table **table)
{
        struct dev_pm_opp *opp;
        struct cpufreq_frequency_table *freq_table = NULL;
        int i, max_opps, ret = 0;
        unsigned long rate;

        max_opps = dev_pm_opp_get_opp_count(dev);
        if (max_opps <= 0)
                return max_opps ? max_opps : -ENODATA;

        freq_table = kcalloc((max_opps + 1), sizeof(*freq_table), GFP_KERNEL);
        if (!freq_table)
                return -ENOMEM;

        for (i = 0, rate = 0; i < max_opps; i++, rate++) {
                /* find next rate */
                opp = dev_pm_opp_find_freq_ceil(dev, &rate);
                if (IS_ERR(opp)) {
                        ret = PTR_ERR(opp);
                        goto out;
                }
                freq_table[i].driver_data = i;
                freq_table[i].frequency = rate / 1000;

                /* Is Boost/turbo opp ? */
                if (dev_pm_opp_is_turbo(opp))
                        freq_table[i].flags = CPUFREQ_BOOST_FREQ;

                dev_pm_opp_put(opp);
        }

        freq_table[i].driver_data = i;
        freq_table[i].frequency = CPUFREQ_TABLE_END;

        *table = &freq_table[0];

out:
        if (ret)
                kfree(freq_table);

        return ret;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_init_cpufreq_table);

/**
 * dev_pm_opp_free_cpufreq_table() - free the cpufreq table
 * @dev:        device for which we do this operation
 * @table:      table to free
 *
 * Free up the table allocated by dev_pm_opp_init_cpufreq_table
 */
void dev_pm_opp_free_cpufreq_table(struct device *dev,
                                   struct cpufreq_frequency_table **table)
{
        if (!table)
                return;

        kfree(*table);
        *table = NULL;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_free_cpufreq_table);
#endif  /* CONFIG_CPU_FREQ */

void _dev_pm_opp_cpumask_remove_table(const struct cpumask *cpumask,
                                      int last_cpu)
{
        struct device *cpu_dev;
        int cpu;

        WARN_ON(cpumask_empty(cpumask));

        for_each_cpu(cpu, cpumask) {
                if (cpu == last_cpu)
                        break;

                cpu_dev = get_cpu_device(cpu);
                if (!cpu_dev) {
                        pr_err("%s: failed to get cpu%d device\n", __func__,
                               cpu);
                        continue;
                }

                _dev_pm_opp_find_and_remove_table(cpu_dev);
        }
}

/**
 * dev_pm_opp_cpumask_remove_table() - Removes OPP table for @cpumask
 * @cpumask:    cpumask for which OPP table needs to be removed
 *
 * This removes the OPP tables for CPUs present in the @cpumask.
 * This should be used to remove all the OPPs entries associated with
 * the cpus in @cpumask.
 */
void dev_pm_opp_cpumask_remove_table(const struct cpumask *cpumask)
{
        _dev_pm_opp_cpumask_remove_table(cpumask, -1);
}
EXPORT_SYMBOL_GPL(dev_pm_opp_cpumask_remove_table);

/**
 * dev_pm_opp_set_sharing_cpus() - Mark OPP table as shared by few CPUs
 * @cpu_dev:    CPU device for which we do this operation
 * @cpumask:    cpumask of the CPUs which share the OPP table with @cpu_dev
 *
 * This marks OPP table of the @cpu_dev as shared by the CPUs present in
 * @cpumask.
 *
 * Returns -ENODEV if OPP table isn't already present.
 */
int dev_pm_opp_set_sharing_cpus(struct device *cpu_dev,
                                const struct cpumask *cpumask)
{
        struct opp_device *opp_dev;
        struct opp_table *opp_table;
        struct device *dev;
        int cpu, ret = 0;

        opp_table = _find_opp_table(cpu_dev);
        if (IS_ERR(opp_table))
                return PTR_ERR(opp_table);

        for_each_cpu(cpu, cpumask) {
                if (cpu == cpu_dev->id)
                        continue;

                dev = get_cpu_device(cpu);
                if (!dev) {
                        dev_err(cpu_dev, "%s: failed to get cpu%d device\n",
                                __func__, cpu);
                        continue;
                }

                opp_dev = _add_opp_dev(dev, opp_table);
                if (!opp_dev) {
                        dev_err(dev, "%s: failed to add opp-dev for cpu%d device\n",
                                __func__, cpu);
                        continue;
                }

                /* Mark opp-table as multiple CPUs are sharing it now */
                opp_table->shared_opp = OPP_TABLE_ACCESS_SHARED;
        }

        dev_pm_opp_put_opp_table(opp_table);

        return ret;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_set_sharing_cpus);

/**
 * dev_pm_opp_get_sharing_cpus() - Get cpumask of CPUs sharing OPPs with @cpu_dev
 * @cpu_dev:    CPU device for which we do this operation
 * @cpumask:    cpumask to update with information of sharing CPUs
 *
 * This updates the @cpumask with CPUs that are sharing OPPs with @cpu_dev.
 *
 * Returns -ENODEV if OPP table isn't already present and -EINVAL if the OPP
 * table's status is access-unknown.
 */
int dev_pm_opp_get_sharing_cpus(struct device *cpu_dev, struct cpumask *cpumask)
{
        struct opp_device *opp_dev;
        struct opp_table *opp_table;
        int ret = 0;

        opp_table = _find_opp_table(cpu_dev);
        if (IS_ERR(opp_table))
                return PTR_ERR(opp_table);

        if (opp_table->shared_opp == OPP_TABLE_ACCESS_UNKNOWN) {
                ret = -EINVAL;
                goto put_opp_table;
        }

        cpumask_clear(cpumask);

        if (opp_table->shared_opp == OPP_TABLE_ACCESS_SHARED) {
                mutex_lock(&opp_table->lock);
                list_for_each_entry(opp_dev, &opp_table->dev_list, node)
                        cpumask_set_cpu(opp_dev->dev->id, cpumask);
                mutex_unlock(&opp_table->lock);
        } else {
                cpumask_set_cpu(cpu_dev->id, cpumask);
        }

put_opp_table:
        dev_pm_opp_put_opp_table(opp_table);

        return ret;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_get_sharing_cpus);