// SPDX-License-Identifier: GPL-2.0-only
/*
 * Generic OPP OF helpers
 *
 * Copyright (C) 2009-2010 Texas Instruments Incorporated.
 *      Nishanth Menon
 *      Romit Dasgupta
 *      Kevin Hilman
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/cpu.h>
#include <linux/errno.h>
#include <linux/device.h>
#include <linux/of_device.h>
#include <linux/pm_domain.h>
#include <linux/slab.h>
#include <linux/export.h>
#include <linux/energy_model.h>

#include "opp.h"

/*
 * Returns opp descriptor node for a device node, caller must
 * do of_node_put().
 */
static struct device_node *_opp_of_get_opp_desc_node(struct device_node *np,
                                                     int index)
{
        /* "operating-points-v2" can be an array for power domain providers */
        return of_parse_phandle(np, "operating-points-v2", index);
}

/* Returns opp descriptor node for a device, caller must do of_node_put() */
struct device_node *dev_pm_opp_of_get_opp_desc_node(struct device *dev)
{
        return _opp_of_get_opp_desc_node(dev->of_node, 0);
}
EXPORT_SYMBOL_GPL(dev_pm_opp_of_get_opp_desc_node);

struct opp_table *_managed_opp(struct device *dev, int index)
{
        struct opp_table *opp_table, *managed_table = NULL;
        struct device_node *np;

        np = _opp_of_get_opp_desc_node(dev->of_node, index);
        if (!np)
                return NULL;

        list_for_each_entry(opp_table, &opp_tables, node) {
                if (opp_table->np == np) {
                        /*
                         * Multiple devices can point to the same OPP table and
                         * so will have same node-pointer, np.
                         *
                         * But the OPPs will be considered as shared only if the
                         * OPP table contains a "opp-shared" property.
                         */
                        if (opp_table->shared_opp == OPP_TABLE_ACCESS_SHARED) {
                                _get_opp_table_kref(opp_table);
                                managed_table = opp_table;
                        }

                        break;
                }
        }

        of_node_put(np);

        return managed_table;
}

/* The caller must call dev_pm_opp_put() after the OPP is used */
static struct dev_pm_opp *_find_opp_of_np(struct opp_table *opp_table,
                                          struct device_node *opp_np)
{
        struct dev_pm_opp *opp;

        mutex_lock(&opp_table->lock);

        list_for_each_entry(opp, &opp_table->opp_list, node) {
                if (opp->np == opp_np) {
                        dev_pm_opp_get(opp);
                        mutex_unlock(&opp_table->lock);
                        return opp;
                }
        }

        mutex_unlock(&opp_table->lock);

        return NULL;
}

static struct device_node *of_parse_required_opp(struct device_node *np,
                                                 int index)
{
        struct device_node *required_np;

        required_np = of_parse_phandle(np, "required-opps", index);
        if (unlikely(!required_np)) {
                pr_err("%s: Unable to parse required-opps: %pOF, index: %d\n",
                       __func__, np, index);
        }

        return required_np;
}

/* The caller must call dev_pm_opp_put_opp_table() after the table is used */
static struct opp_table *_find_table_of_opp_np(struct device_node *opp_np)
{
        struct opp_table *opp_table;
        struct device_node *opp_table_np;

        lockdep_assert_held(&opp_table_lock);

        opp_table_np = of_get_parent(opp_np);
        if (!opp_table_np)
                goto err;

        /* It is safe to put the node now as all we need now is its address */
        of_node_put(opp_table_np);

        list_for_each_entry(opp_table, &opp_tables, node) {
                if (opp_table_np == opp_table->np) {
                        _get_opp_table_kref(opp_table);
                        return opp_table;
                }
        }

err:
        return ERR_PTR(-ENODEV);
}

/* Free resources previously acquired by _opp_table_alloc_required_tables() */
static void _opp_table_free_required_tables(struct opp_table *opp_table)
{
        struct opp_table **required_opp_tables = opp_table->required_opp_tables;
        int i;

        if (!required_opp_tables)
                return;

        for (i = 0; i < opp_table->required_opp_count; i++) {
                if (IS_ERR_OR_NULL(required_opp_tables[i]))
                        break;

                dev_pm_opp_put_opp_table(required_opp_tables[i]);
        }

        kfree(required_opp_tables);

        opp_table->required_opp_count = 0;
        opp_table->required_opp_tables = NULL;
}

/*
 * Populate all devices and opp tables which are part of "required-opps" list.
 * Checking only the first OPP node should be enough.
 */
static void _opp_table_alloc_required_tables(struct opp_table *opp_table,
                                             struct device *dev,
                                             struct device_node *opp_np)
{
        struct opp_table **required_opp_tables;
        struct device_node *required_np, *np;
        int count, i;

        /* Traversing the first OPP node is all we need */
        np = of_get_next_available_child(opp_np, NULL);
        if (!np) {
                dev_err(dev, "Empty OPP table\n");
                return;
        }

        count = of_count_phandle_with_args(np, "required-opps", NULL);
        if (!count)
                goto put_np;

        required_opp_tables = kcalloc(count, sizeof(*required_opp_tables),
                                      GFP_KERNEL);
        if (!required_opp_tables)
                goto put_np;

        opp_table->required_opp_tables = required_opp_tables;
        opp_table->required_opp_count = count;

        for (i = 0; i < count; i++) {
                required_np = of_parse_required_opp(np, i);
                if (!required_np)
                        goto free_required_tables;

                required_opp_tables[i] = _find_table_of_opp_np(required_np);
                of_node_put(required_np);

                if (IS_ERR(required_opp_tables[i]))
                        goto free_required_tables;

                /*
                 * We only support genpd's OPPs in the "required-opps" for now,
                 * as we don't know how much about other cases. Error out if the
                 * required OPP doesn't belong to a genpd.
                 */
                if (!required_opp_tables[i]->is_genpd) {
                        dev_err(dev, "required-opp doesn't belong to genpd: %pOF\n",
                                required_np);
                        goto free_required_tables;
                }
        }

        goto put_np;

free_required_tables:
        _opp_table_free_required_tables(opp_table);
put_np:
        of_node_put(np);
}

void _of_init_opp_table(struct opp_table *opp_table, struct device *dev,
                        int index)
{
        struct device_node *np, *opp_np;
        u32 val;

        /*
         * Only required for backward compatibility with v1 bindings, but isn't
         * harmful for other cases. And so we do it unconditionally.
         */
        np = of_node_get(dev->of_node);
        if (!np)
                return;

        if (!of_property_read_u32(np, "clock-latency", &val))
                opp_table->clock_latency_ns_max = val;
        of_property_read_u32(np, "voltage-tolerance",
                             &opp_table->voltage_tolerance_v1);

        if (of_find_property(np, "#power-domain-cells", NULL))
                opp_table->is_genpd = true;

        /* Get OPP table node */
        opp_np = _opp_of_get_opp_desc_node(np, index);
        of_node_put(np);

        if (!opp_np)
                return;

        if (of_property_read_bool(opp_np, "opp-shared"))
                opp_table->shared_opp = OPP_TABLE_ACCESS_SHARED;
        else
                opp_table->shared_opp = OPP_TABLE_ACCESS_EXCLUSIVE;

        opp_table->np = opp_np;

        _opp_table_alloc_required_tables(opp_table, dev, opp_np);
        of_node_put(opp_np);
}

void _of_clear_opp_table(struct opp_table *opp_table)
{
        _opp_table_free_required_tables(opp_table);
}

/*
 * Release all resources previously acquired with a call to
 * _of_opp_alloc_required_opps().
 */
void _of_opp_free_required_opps(struct opp_table *opp_table,
                                struct dev_pm_opp *opp)
{
        struct dev_pm_opp **required_opps = opp->required_opps;
        int i;

        if (!required_opps)
                return;

        for (i = 0; i < opp_table->required_opp_count; i++) {
                if (!required_opps[i])
                        break;

                /* Put the reference back */
                dev_pm_opp_put(required_opps[i]);
        }

        kfree(required_opps);
        opp->required_opps = NULL;
}

/* Populate all required OPPs which are part of "required-opps" list */
static int _of_opp_alloc_required_opps(struct opp_table *opp_table,
                                       struct dev_pm_opp *opp)
{
        struct dev_pm_opp **required_opps;
        struct opp_table *required_table;
        struct device_node *np;
        int i, ret, count = opp_table->required_opp_count;

        if (!count)
                return 0;

        required_opps = kcalloc(count, sizeof(*required_opps), GFP_KERNEL);
        if (!required_opps)
                return -ENOMEM;

        opp->required_opps = required_opps;

        for (i = 0; i < count; i++) {
                required_table = opp_table->required_opp_tables[i];

                np = of_parse_required_opp(opp->np, i);
                if (unlikely(!np)) {
                        ret = -ENODEV;
                        goto free_required_opps;
                }

                required_opps[i] = _find_opp_of_np(required_table, np);
                of_node_put(np);

                if (!required_opps[i]) {
                        pr_err("%s: Unable to find required OPP node: %pOF (%d)\n",
                               __func__, opp->np, i);
                        ret = -ENODEV;
                        goto free_required_opps;
                }
        }

        return 0;

free_required_opps:
        _of_opp_free_required_opps(opp_table, opp);

        return ret;
}

static int _bandwidth_supported(struct device *dev, struct opp_table *opp_table)
{
        struct device_node *np, *opp_np;
        struct property *prop;

        if (!opp_table) {
                np = of_node_get(dev->of_node);
                if (!np)
                        return -ENODEV;

                opp_np = _opp_of_get_opp_desc_node(np, 0);
                of_node_put(np);
        } else {
                opp_np = of_node_get(opp_table->np);
        }

        /* Lets not fail in case we are parsing opp-v1 bindings */
        if (!opp_np)
                return 0;

        /* Checking only first OPP is sufficient */
        np = of_get_next_available_child(opp_np, NULL);
        if (!np) {
                dev_err(dev, "OPP table empty\n");
                return -EINVAL;
        }
        of_node_put(opp_np);

        prop = of_find_property(np, "opp-peak-kBps", NULL);
        of_node_put(np);

        if (!prop || !prop->length)
                return 0;

        return 1;
}

int dev_pm_opp_of_find_icc_paths(struct device *dev,
                                 struct opp_table *opp_table)
{
        struct device_node *np;
        int ret, i, count, num_paths;
        struct icc_path **paths;

        ret = _bandwidth_supported(dev, opp_table);
        if (ret <= 0)
                return ret;

        ret = 0;

        np = of_node_get(dev->of_node);
        if (!np)
                return 0;

        count = of_count_phandle_with_args(np, "interconnects",
                                           "#interconnect-cells");
        of_node_put(np);
        if (count < 0)
                return 0;

        /* two phandles when #interconnect-cells = <1> */
        if (count % 2) {
                dev_err(dev, "%s: Invalid interconnects values\n", __func__);
                return -EINVAL;
        }

        num_paths = count / 2;
        paths = kcalloc(num_paths, sizeof(*paths), GFP_KERNEL);
        if (!paths)
                return -ENOMEM;

        for (i = 0; i < num_paths; i++) {
                paths[i] = of_icc_get_by_index(dev, i);
                if (IS_ERR(paths[i])) {
                        ret = PTR_ERR(paths[i]);
                        if (ret != -EPROBE_DEFER) {
                                dev_err(dev, "%s: Unable to get path%d: %d\n",
                                        __func__, i, ret);
                        }
                        goto err;
                }
        }

        if (opp_table) {
                opp_table->paths = paths;
                opp_table->path_count = num_paths;
                return 0;
        }

err:
        while (i--)
                icc_put(paths[i]);

        kfree(paths);

        return ret;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_of_find_icc_paths);

static bool _opp_is_supported(struct device *dev, struct opp_table *opp_table,
                              struct device_node *np)
{
        unsigned int levels = opp_table->supported_hw_count;
        int count, versions, ret, i, j;
        u32 val;

        if (!opp_table->supported_hw) {
                /*
                 * In the case that no supported_hw has been set by the
                 * platform but there is an opp-supported-hw value set for
                 * an OPP then the OPP should not be enabled as there is
                 * no way to see if the hardware supports it.
                 */
                if (of_find_property(np, "opp-supported-hw", NULL))
                        return false;
                else
                        return true;
        }

        count = of_property_count_u32_elems(np, "opp-supported-hw");
        if (count <= 0 || count % levels) {
                dev_err(dev, "%s: Invalid opp-supported-hw property (%d)\n",
                        __func__, count);
                return false;
        }

        versions = count / levels;

        /* All levels in at least one of the versions should match */
        for (i = 0; i < versions; i++) {
                bool supported = true;

                for (j = 0; j < levels; j++) {
                        ret = of_property_read_u32_index(np, "opp-supported-hw",
                                                         i * levels + j, &val);
                        if (ret) {
                                dev_warn(dev, "%s: failed to read opp-supported-hw property at index %d: %d\n",
                                         __func__, i * levels + j, ret);
                                return false;
                        }

                        /* Check if the level is supported */
                        if (!(val & opp_table->supported_hw[j])) {
                                supported = false;
                                break;
                        }
                }

                if (supported)
                        return true;
        }

        return false;
}

static int opp_parse_supplies(struct dev_pm_opp *opp, struct device *dev,
                              struct opp_table *opp_table)
{
        u32 *microvolt, *microamp = NULL;
        int supplies = opp_table->regulator_count, vcount, icount, ret, i, j;
        struct property *prop = NULL;
        char name[NAME_MAX];

        /* Search for "opp-microvolt-<name>" */
        if (opp_table->prop_name) {
                snprintf(name, sizeof(name), "opp-microvolt-%s",
                         opp_table->prop_name);
                prop = of_find_property(opp->np, name, NULL);
        }

        if (!prop) {
                /* Search for "opp-microvolt" */
                sprintf(name, "opp-microvolt");
                prop = of_find_property(opp->np, name, NULL);

                /* Missing property isn't a problem, but an invalid entry is */
                if (!prop) {
                        if (unlikely(supplies == -1)) {
                                /* Initialize regulator_count */
                                opp_table->regulator_count = 0;
                                return 0;
                        }

                        if (!supplies)
                                return 0;

                        dev_err(dev, "%s: opp-microvolt missing although OPP managing regulators\n",
                                __func__);
                        return -EINVAL;
                }
        }

        if (unlikely(supplies == -1)) {
                /* Initialize regulator_count */
                supplies = opp_table->regulator_count = 1;
        } else if (unlikely(!supplies)) {
                dev_err(dev, "%s: opp-microvolt wasn't expected\n", __func__);
                return -EINVAL;
        }

        vcount = of_property_count_u32_elems(opp->np, name);
        if (vcount < 0) {
                dev_err(dev, "%s: Invalid %s property (%d)\n",
                        __func__, name, vcount);
                return vcount;
        }

        /* There can be one or three elements per supply */
        if (vcount != supplies && vcount != supplies * 3) {
                dev_err(dev, "%s: Invalid number of elements in %s property (%d) with supplies (%d)\n",
                        __func__, name, vcount, supplies);
                return -EINVAL;
        }

        microvolt = kmalloc_array(vcount, sizeof(*microvolt), GFP_KERNEL);
        if (!microvolt)
                return -ENOMEM;

        ret = of_property_read_u32_array(opp->np, name, microvolt, vcount);
        if (ret) {
                dev_err(dev, "%s: error parsing %s: %d\n", __func__, name, ret);
                ret = -EINVAL;
                goto free_microvolt;
        }

        /* Search for "opp-microamp-<name>" */
        prop = NULL;
        if (opp_table->prop_name) {
                snprintf(name, sizeof(name), "opp-microamp-%s",
                         opp_table->prop_name);
                prop = of_find_property(opp->np, name, NULL);
        }

        if (!prop) {
                /* Search for "opp-microamp" */
                sprintf(name, "opp-microamp");
                prop = of_find_property(opp->np, name, NULL);
        }

        if (prop) {
                icount = of_property_count_u32_elems(opp->np, name);
                if (icount < 0) {
                        dev_err(dev, "%s: Invalid %s property (%d)\n", __func__,
                                name, icount);
                        ret = icount;
                        goto free_microvolt;
                }

                if (icount != supplies) {
                        dev_err(dev, "%s: Invalid number of elements in %s property (%d) with supplies (%d)\n",
                                __func__, name, icount, supplies);
                        ret = -EINVAL;
                        goto free_microvolt;
                }

                microamp = kmalloc_array(icount, sizeof(*microamp), GFP_KERNEL);
                if (!microamp) {
                        ret = -EINVAL;
                        goto free_microvolt;
                }

                ret = of_property_read_u32_array(opp->np, name, microamp,
                                                 icount);
                if (ret) {
                        dev_err(dev, "%s: error parsing %s: %d\n", __func__,
                                name, ret);
                        ret = -EINVAL;
                        goto free_microamp;
                }
        }

        for (i = 0, j = 0; i < supplies; i++) {
                opp->supplies[i].u_volt = microvolt[j++];

                if (vcount == supplies) {
                        opp->supplies[i].u_volt_min = opp->supplies[i].u_volt;
                        opp->supplies[i].u_volt_max = opp->supplies[i].u_volt;
                } else {
                        opp->supplies[i].u_volt_min = microvolt[j++];
                        opp->supplies[i].u_volt_max = microvolt[j++];
                }

                if (microamp)
                        opp->supplies[i].u_amp = microamp[i];
        }

free_microamp:
        kfree(microamp);
free_microvolt:
        kfree(microvolt);

        return ret;
}

/**
 * dev_pm_opp_of_remove_table() - Free OPP table entries created from static DT
 *                                entries
 * @dev:        device pointer used to lookup OPP table.
 *
 * Free OPPs created using static entries present in DT.
 */
void dev_pm_opp_of_remove_table(struct device *dev)
{
        dev_pm_opp_remove_table(dev);
}
EXPORT_SYMBOL_GPL(dev_pm_opp_of_remove_table);

static int _read_bw(struct dev_pm_opp *new_opp, struct opp_table *table,
                    struct device_node *np, bool peak)
{
        const char *name = peak ? "opp-peak-kBps" : "opp-avg-kBps";
        struct property *prop;
        int i, count, ret;
        u32 *bw;

        prop = of_find_property(np, name, NULL);
        if (!prop)
                return -ENODEV;

        count = prop->length / sizeof(u32);
        if (table->path_count != count) {
                pr_err("%s: Mismatch between %s and paths (%d %d)\n",
                                __func__, name, count, table->path_count);
                return -EINVAL;
        }

        bw = kmalloc_array(count, sizeof(*bw), GFP_KERNEL);
        if (!bw)
                return -ENOMEM;

        ret = of_property_read_u32_array(np, name, bw, count);
        if (ret) {
                pr_err("%s: Error parsing %s: %d\n", __func__, name, ret);
                goto out;
        }

        for (i = 0; i < count; i++) {
                if (peak)
                        new_opp->bandwidth[i].peak = kBps_to_icc(bw[i]);
                else
                        new_opp->bandwidth[i].avg = kBps_to_icc(bw[i]);
        }

out:
        kfree(bw);
        return ret;
}

static int _read_opp_key(struct dev_pm_opp *new_opp, struct opp_table *table,
                         struct device_node *np, bool *rate_not_available)
{
        bool found = false;
        u64 rate;
        int ret;

        ret = of_property_read_u64(np, "opp-hz", &rate);
        if (!ret) {
                /*
                 * Rate is defined as an unsigned long in clk API, and so
                 * casting explicitly to its type. Must be fixed once rate is 64
                 * bit guaranteed in clk API.
                 */
                new_opp->rate = (unsigned long)rate;
                found = true;
        }
        *rate_not_available = !!ret;

        /*
         * Bandwidth consists of peak and average (optional) values:
         * opp-peak-kBps = <path1_value path2_value>;
         * opp-avg-kBps = <path1_value path2_value>;
         */
        ret = _read_bw(new_opp, table, np, true);
        if (!ret) {
                found = true;
                ret = _read_bw(new_opp, table, np, false);
        }

        /* The properties were found but we failed to parse them */
        if (ret && ret != -ENODEV)
                return ret;

        if (!of_property_read_u32(np, "opp-level", &new_opp->level))
                found = true;

        if (found)
                return 0;

        return ret;
}

/**
 * _opp_add_static_v2() - Allocate static OPPs (As per 'v2' DT bindings)
 * @opp_table:  OPP table
 * @dev:        device for which we do this operation
 * @np:         device node
 *
 * This function adds an opp definition to the opp table and returns status. The
 * opp can be controlled using dev_pm_opp_enable/disable functions and may be
 * removed by dev_pm_opp_remove.
 *
 * Return:
 * Valid OPP pointer:
 *              On success
 * NULL:
 *              Duplicate OPPs (both freq and volt are same) and opp->available
 *              OR if the OPP is not supported by hardware.
 * ERR_PTR(-EEXIST):
 *              Freq are same and volt are different OR
 *              Duplicate OPPs (both freq and volt are same) and !opp->available
 * ERR_PTR(-ENOMEM):
 *              Memory allocation failure
 * ERR_PTR(-EINVAL):
 *              Failed parsing the OPP node
 */
static struct dev_pm_opp *_opp_add_static_v2(struct opp_table *opp_table,
                struct device *dev, struct device_node *np)
{
        struct dev_pm_opp *new_opp;
        u64 rate = 0;
        u32 val;
        int ret;
        bool rate_not_available = false;

        new_opp = _opp_allocate(opp_table);
        if (!new_opp)
                return ERR_PTR(-ENOMEM);

        ret = _read_opp_key(new_opp, opp_table, np, &rate_not_available);
        if (ret < 0 && !opp_table->is_genpd) {
                dev_err(dev, "%s: opp key field not found\n", __func__);
                goto free_opp;
        }

        /* Check if the OPP supports hardware's hierarchy of versions or not */
        if (!_opp_is_supported(dev, opp_table, np)) {
                dev_dbg(dev, "OPP not supported by hardware: %llu\n", rate);
                goto free_opp;
        }

        new_opp->turbo = of_property_read_bool(np, "turbo-mode");

        new_opp->np = np;
        new_opp->dynamic = false;
        new_opp->available = true;

        ret = _of_opp_alloc_required_opps(opp_table, new_opp);
        if (ret)
                goto free_opp;

        if (!of_property_read_u32(np, "clock-latency-ns", &val))
                new_opp->clock_latency_ns = val;

        ret = opp_parse_supplies(new_opp, dev, opp_table);
        if (ret)
                goto free_required_opps;

        if (opp_table->is_genpd)
                new_opp->pstate = pm_genpd_opp_to_performance_state(dev, new_opp);

        ret = _opp_add(dev, new_opp, opp_table, rate_not_available);
        if (ret) {
                /* Don't return error for duplicate OPPs */
                if (ret == -EBUSY)
                        ret = 0;
                goto free_required_opps;
        }

        /* OPP to select on device suspend */
        if (of_property_read_bool(np, "opp-suspend")) {
                if (opp_table->suspend_opp) {
                        /* Pick the OPP with higher rate as suspend OPP */
                        if (new_opp->rate > opp_table->suspend_opp->rate) {
                                opp_table->suspend_opp->suspend = false;
                                new_opp->suspend = true;
                                opp_table->suspend_opp = new_opp;
                        }
                } else {
                        new_opp->suspend = true;
                        opp_table->suspend_opp = new_opp;
                }
        }

        if (new_opp->clock_latency_ns > opp_table->clock_latency_ns_max)
                opp_table->clock_latency_ns_max = new_opp->clock_latency_ns;

        pr_debug("%s: turbo:%d rate:%lu uv:%lu uvmin:%lu uvmax:%lu latency:%lu\n",
                 __func__, new_opp->turbo, new_opp->rate,
                 new_opp->supplies[0].u_volt, new_opp->supplies[0].u_volt_min,
                 new_opp->supplies[0].u_volt_max, new_opp->clock_latency_ns);

        /*
         * Notify the changes in the availability of the operable
         * frequency/voltage list.
         */
        blocking_notifier_call_chain(&opp_table->head, OPP_EVENT_ADD, new_opp);
        return new_opp;

free_required_opps:
        _of_opp_free_required_opps(opp_table, new_opp);
free_opp:
        _opp_free(new_opp);

        return ERR_PTR(ret);
}

/* Initializes OPP tables based on new bindings */
static int _of_add_opp_table_v2(struct device *dev, struct opp_table *opp_table)
{
        struct device_node *np;
        int ret, count = 0;
        struct dev_pm_opp *opp;

        /* OPP table is already initialized for the device */
        mutex_lock(&opp_table->lock);
        if (opp_table->parsed_static_opps) {
                opp_table->parsed_static_opps++;
                mutex_unlock(&opp_table->lock);
                return 0;
        }

        opp_table->parsed_static_opps = 1;
        mutex_unlock(&opp_table->lock);

        /* We have opp-table node now, iterate over it and add OPPs */
        for_each_available_child_of_node(opp_table->np, np) {
                opp = _opp_add_static_v2(opp_table, dev, np);
                if (IS_ERR(opp)) {
                        ret = PTR_ERR(opp);
                        dev_err(dev, "%s: Failed to add OPP, %d\n", __func__,
                                ret);
                        of_node_put(np);
                        goto remove_static_opp;
                } else if (opp) {
                        count++;
                }
        }

        /* There should be one of more OPP defined */
        if (WARN_ON(!count)) {
                ret = -ENOENT;
                goto remove_static_opp;
        }

        list_for_each_entry(opp, &opp_table->opp_list, node) {
                /* Any non-zero performance state would enable the feature */
                if (opp->pstate) {
                        opp_table->genpd_performance_state = true;
                        break;
                }
        }

        return 0;

remove_static_opp:
        _opp_remove_all_static(opp_table);

        return ret;
}

/* Initializes OPP tables based on old-deprecated bindings */
static int _of_add_opp_table_v1(struct device *dev, struct opp_table *opp_table)
{
        const struct property *prop;
        const __be32 *val;
        int nr, ret = 0;

        mutex_lock(&opp_table->lock);
        if (opp_table->parsed_static_opps) {
                opp_table->parsed_static_opps++;
                mutex_unlock(&opp_table->lock);
                return 0;
        }

        opp_table->parsed_static_opps = 1;
        mutex_unlock(&opp_table->lock);

        prop = of_find_property(dev->of_node, "operating-points", NULL);
        if (!prop) {
                ret = -ENODEV;
                goto remove_static_opp;
        }
        if (!prop->value) {
                ret = -ENODATA;
                goto remove_static_opp;
        }

        /*
         * Each OPP is a set of tuples consisting of frequency and
         * voltage like <freq-kHz vol-uV>.
         */
        nr = prop->length / sizeof(u32);
        if (nr % 2) {
                dev_err(dev, "%s: Invalid OPP table\n", __func__);
                ret = -EINVAL;
                goto remove_static_opp;
        }

        val = prop->value;
        while (nr) {
                unsigned long freq = be32_to_cpup(val++) * 1000;
                unsigned long volt = be32_to_cpup(val++);

                ret = _opp_add_v1(opp_table, dev, freq, volt, false);
                if (ret) {
                        dev_err(dev, "%s: Failed to add OPP %ld (%d)\n",
                                __func__, freq, ret);
                        goto remove_static_opp;
                }
                nr -= 2;
        }

        return 0;

remove_static_opp:
        _opp_remove_all_static(opp_table);

        return ret;
}

/**
 * dev_pm_opp_of_add_table() - Initialize opp table from device tree
 * @dev:        device pointer used to lookup OPP table.
 *
 * Register the initial OPP table with the OPP library for given device.
 *
 * Return:
 * 0            On success OR
 *              Duplicate OPPs (both freq and volt are same) and opp->available
 * -EEXIST      Freq are same and volt are different OR
 *              Duplicate OPPs (both freq and volt are same) and !opp->available
 * -ENOMEM      Memory allocation failure
 * -ENODEV      when 'operating-points' property is not found or is invalid data
 *              in device node.
 * -ENODATA     when empty 'operating-points' property is found
 * -EINVAL      when invalid entries are found in opp-v2 table
 */
int dev_pm_opp_of_add_table(struct device *dev)
{
        struct opp_table *opp_table;
        int ret;

        opp_table = dev_pm_opp_get_opp_table_indexed(dev, 0);
        if (IS_ERR(opp_table))
                return PTR_ERR(opp_table);

        /*
         * OPPs have two version of bindings now. Also try the old (v1)
         * bindings for backward compatibility with older dtbs.
         */
        if (opp_table->np)
                ret = _of_add_opp_table_v2(dev, opp_table);
        else
                ret = _of_add_opp_table_v1(dev, opp_table);

        if (ret)
                dev_pm_opp_put_opp_table(opp_table);

        return ret;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_of_add_table);

/**
 * dev_pm_opp_of_add_table_indexed() - Initialize indexed opp table from device tree
 * @dev:        device pointer used to lookup OPP table.
 * @index:      Index number.

 *
 * Register the initial OPP table with the OPP library for given device only
 * using the "operating-points-v2" property.
 *
 * Return:
 * 0            On success OR
 *              Duplicate OPPs (both freq and volt are same) and opp->available
 * -EEXIST      Freq are same and volt are different OR
 *              Duplicate OPPs (both freq and volt are same) and !opp->available
 * -ENOMEM      Memory allocation failure
 * -ENODEV      when 'operating-points' property is not found or is invalid data
 *              in device node.
 * -ENODATA     when empty 'operating-points' property is found
 * -EINVAL      when invalid entries are found in opp-v2 table
 */
int dev_pm_opp_of_add_table_indexed(struct device *dev, int index)
{
        struct opp_table *opp_table;
        int ret, count;

        if (index) {
                /*
                 * If only one phandle is present, then the same OPP table
                 * applies for all index requests.
                 */
                count = of_count_phandle_with_args(dev->of_node,
                                                   "operating-points-v2", NULL);
                if (count == 1)
                        index = 0;
        }

        opp_table = dev_pm_opp_get_opp_table_indexed(dev, index);
        if (IS_ERR(opp_table))
                return PTR_ERR(opp_table);

        ret = _of_add_opp_table_v2(dev, opp_table);
        if (ret)
                dev_pm_opp_put_opp_table(opp_table);

        return ret;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_of_add_table_indexed);

/* CPU device specific helpers */

/**
 * dev_pm_opp_of_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 only to remove static entries created from DT.
 */
void dev_pm_opp_of_cpumask_remove_table(const struct cpumask *cpumask)
{
        _dev_pm_opp_cpumask_remove_table(cpumask, -1);
}
EXPORT_SYMBOL_GPL(dev_pm_opp_of_cpumask_remove_table);

/**
 * dev_pm_opp_of_cpumask_add_table() - Adds OPP table for @cpumask
 * @cpumask:    cpumask for which OPP table needs to be added.
 *
 * This adds the OPP tables for CPUs present in the @cpumask.
 */
int dev_pm_opp_of_cpumask_add_table(const struct cpumask *cpumask)
{
        struct device *cpu_dev;
        int cpu, ret;

        if (WARN_ON(cpumask_empty(cpumask)))
                return -ENODEV;

        for_each_cpu(cpu, cpumask) {
                cpu_dev = get_cpu_device(cpu);
                if (!cpu_dev) {
                        pr_err("%s: failed to get cpu%d device\n", __func__,
                               cpu);
                        ret = -ENODEV;
                        goto remove_table;
                }

                ret = dev_pm_opp_of_add_table(cpu_dev);
                if (ret) {
                        /*
                         * OPP may get registered dynamically, don't print error
                         * message here.
                         */
                        pr_debug("%s: couldn't find opp table for cpu:%d, %d\n",
                                 __func__, cpu, ret);

                        goto remove_table;
                }
        }

        return 0;

remove_table:
        /* Free all other OPPs */
        _dev_pm_opp_cpumask_remove_table(cpumask, cpu);

        return ret;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_of_cpumask_add_table);

/*
 * Works only for OPP v2 bindings.
 *
 * Returns -ENOENT if operating-points-v2 bindings aren't supported.
 */
/**
 * dev_pm_opp_of_get_sharing_cpus() - Get cpumask of CPUs sharing OPPs with
 *                                    @cpu_dev using operating-points-v2
 *                                    bindings.
 *
 * @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 -ENOENT if operating-points-v2 isn't present for @cpu_dev.
 */
int dev_pm_opp_of_get_sharing_cpus(struct device *cpu_dev,
                                   struct cpumask *cpumask)
{
        struct device_node *np, *tmp_np, *cpu_np;
        int cpu, ret = 0;

        /* Get OPP descriptor node */
        np = dev_pm_opp_of_get_opp_desc_node(cpu_dev);
        if (!np) {
                dev_dbg(cpu_dev, "%s: Couldn't find opp node.\n", __func__);
                return -ENOENT;
        }

        cpumask_set_cpu(cpu_dev->id, cpumask);

        /* OPPs are shared ? */
        if (!of_property_read_bool(np, "opp-shared"))
                goto put_cpu_node;

        for_each_possible_cpu(cpu) {
                if (cpu == cpu_dev->id)
                        continue;

                cpu_np = of_cpu_device_node_get(cpu);
                if (!cpu_np) {
                        dev_err(cpu_dev, "%s: failed to get cpu%d node\n",
                                __func__, cpu);
                        ret = -ENOENT;
                        goto put_cpu_node;
                }

                /* Get OPP descriptor node */
                tmp_np = _opp_of_get_opp_desc_node(cpu_np, 0);
                of_node_put(cpu_np);
                if (!tmp_np) {
                        pr_err("%pOF: Couldn't find opp node\n", cpu_np);
                        ret = -ENOENT;
                        goto put_cpu_node;
                }

                /* CPUs are sharing opp node */
                if (np == tmp_np)
                        cpumask_set_cpu(cpu, cpumask);

                of_node_put(tmp_np);
        }

put_cpu_node:
        of_node_put(np);
        return ret;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_of_get_sharing_cpus);

/**
 * of_get_required_opp_performance_state() - Search for required OPP and return its performance state.
 * @np: Node that contains the "required-opps" property.
 * @index: Index of the phandle to parse.
 *
 * Returns the performance state of the OPP pointed out by the "required-opps"
 * property at @index in @np.
 *
 * Return: Zero or positive performance state on success, otherwise negative
 * value on errors.
 */
int of_get_required_opp_performance_state(struct device_node *np, int index)
{
        struct dev_pm_opp *opp;
        struct device_node *required_np;
        struct opp_table *opp_table;
        int pstate = -EINVAL;

        required_np = of_parse_required_opp(np, index);
        if (!required_np)
                return -EINVAL;

        opp_table = _find_table_of_opp_np(required_np);
        if (IS_ERR(opp_table)) {
                pr_err("%s: Failed to find required OPP table %pOF: %ld\n",
                       __func__, np, PTR_ERR(opp_table));
                goto put_required_np;
        }

        opp = _find_opp_of_np(opp_table, required_np);
        if (opp) {
                pstate = opp->pstate;
                dev_pm_opp_put(opp);
        }

        dev_pm_opp_put_opp_table(opp_table);

put_required_np:
        of_node_put(required_np);

        return pstate;
}
EXPORT_SYMBOL_GPL(of_get_required_opp_performance_state);

/**
 * dev_pm_opp_get_of_node() - Gets the DT node corresponding to an opp
 * @opp:        opp for which DT node has to be returned for
 *
 * Return: DT node corresponding to the opp, else 0 on success.
 *
 * The caller needs to put the node with of_node_put() after using it.
 */
struct device_node *dev_pm_opp_get_of_node(struct dev_pm_opp *opp)
{
        if (IS_ERR_OR_NULL(opp)) {
                pr_err("%s: Invalid parameters\n", __func__);
                return NULL;
        }

        return of_node_get(opp->np);
}
EXPORT_SYMBOL_GPL(dev_pm_opp_get_of_node);

/*
 * Callback function provided to the Energy Model framework upon registration.
 * This computes the power estimated by @dev at @kHz if it is the frequency
 * of an existing OPP, or at the frequency of the first OPP above @kHz otherwise
 * (see dev_pm_opp_find_freq_ceil()). This function updates @kHz to the ceiled
 * frequency and @mW to the associated power. The power is estimated as
 * P = C * V^2 * f with C being the device's capacitance and V and f
 * respectively the voltage and frequency of the OPP.
 *
 * Returns -EINVAL if the power calculation failed because of missing
 * parameters, 0 otherwise.
 */
static int __maybe_unused _get_power(unsigned long *mW, unsigned long *kHz,
                                     struct device *dev)
{
        struct dev_pm_opp *opp;
        struct device_node *np;
        unsigned long mV, Hz;
        u32 cap;
        u64 tmp;
        int ret;

        np = of_node_get(dev->of_node);
        if (!np)
                return -EINVAL;

        ret = of_property_read_u32(np, "dynamic-power-coefficient", &cap);
        of_node_put(np);
        if (ret)
                return -EINVAL;

        Hz = *kHz * 1000;
        opp = dev_pm_opp_find_freq_ceil(dev, &Hz);
        if (IS_ERR(opp))
                return -EINVAL;

        mV = dev_pm_opp_get_voltage(opp) / 1000;
        dev_pm_opp_put(opp);
        if (!mV)
                return -EINVAL;

        tmp = (u64)cap * mV * mV * (Hz / 1000000);
        do_div(tmp, 1000000000);

        *mW = (unsigned long)tmp;
        *kHz = Hz / 1000;

        return 0;
}

/**
 * dev_pm_opp_of_register_em() - Attempt to register an Energy Model
 * @dev         : Device for which an Energy Model has to be registered
 * @cpus        : CPUs for which an Energy Model has to be registered. For
 *              other type of devices it should be set to NULL.
 *
 * This checks whether the "dynamic-power-coefficient" devicetree property has
 * been specified, and tries to register an Energy Model with it if it has.
 * Having this property means the voltages are known for OPPs and the EM
 * might be calculated.
 */
int dev_pm_opp_of_register_em(struct device *dev, struct cpumask *cpus)
{
        struct em_data_callback em_cb = EM_DATA_CB(_get_power);
        struct device_node *np;
        int ret, nr_opp;
        u32 cap;

        if (IS_ERR_OR_NULL(dev)) {
                ret = -EINVAL;
                goto failed;
        }

        nr_opp = dev_pm_opp_get_opp_count(dev);
        if (nr_opp <= 0) {
                ret = -EINVAL;
                goto failed;
        }

        np = of_node_get(dev->of_node);
        if (!np) {
                ret = -EINVAL;
                goto failed;
        }

        /*
         * Register an EM only if the 'dynamic-power-coefficient' property is
         * set in devicetree. It is assumed the voltage values are known if that
         * property is set since it is useless otherwise. If voltages are not
         * known, just let the EM registration fail with an error to alert the
         * user about the inconsistent configuration.
         */
        ret = of_property_read_u32(np, "dynamic-power-coefficient", &cap);
        of_node_put(np);
        if (ret || !cap) {
                dev_dbg(dev, "Couldn't find proper 'dynamic-power-coefficient' in DT\n");
                ret = -EINVAL;
                goto failed;
        }

        ret = em_dev_register_perf_domain(dev, nr_opp, &em_cb, cpus);
        if (ret)
                goto failed;

        return 0;

failed:
        dev_dbg(dev, "Couldn't register Energy Model %d\n", ret);
        return ret;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_of_register_em);