// SPDX-License-Identifier: GPL-2.0-only
/*
 * PM domains for CPUs via genpd.
 *
 * Copyright (C) 2019 Linaro Ltd.
 * Author: Ulf Hansson <ulf.hansson@linaro.org>
 *
 * Copyright (c) 2021 Western Digital Corporation or its affiliates.
 * Copyright (c) 2022 Ventana Micro Systems Inc.
 */

#define pr_fmt(fmt) "dt-idle-genpd: " fmt

#include <linux/cpu.h>
#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/pm_domain.h>
#include <linux/pm_runtime.h>
#include <linux/slab.h>
#include <linux/string.h>

#include "dt_idle_genpd.h"

static int pd_parse_state_nodes(
                        int (*parse_state)(struct device_node *, u32 *),
                        struct genpd_power_state *states, int state_count)
{
        int i, ret;
        u32 state, *state_buf;

        for (i = 0; i < state_count; i++) {
                ret = parse_state(to_of_node(states[i].fwnode), &state);
                if (ret)
                        goto free_state;

                state_buf = kmalloc(sizeof(u32), GFP_KERNEL);
                if (!state_buf) {
                        ret = -ENOMEM;
                        goto free_state;
                }
                *state_buf = state;
                states[i].data = state_buf;
        }

        return 0;

free_state:
        i--;
        for (; i >= 0; i--)
                kfree(states[i].data);
        return ret;
}

static int pd_parse_states(struct device_node *np,
                           int (*parse_state)(struct device_node *, u32 *),
                           struct genpd_power_state **states,
                           int *state_count)
{
        int ret;

        /* Parse the domain idle states. */
        ret = of_genpd_parse_idle_states(np, states, state_count);
        if (ret)
                return ret;

        /* Fill out the dt specifics for each found state. */
        ret = pd_parse_state_nodes(parse_state, *states, *state_count);
        if (ret)
                kfree(*states);

        return ret;
}

static void pd_free_states(struct genpd_power_state *states,
                            unsigned int state_count)
{
        int i;

        for (i = 0; i < state_count; i++)
                kfree(states[i].data);
        kfree(states);
}

void dt_idle_pd_free(struct generic_pm_domain *pd)
{
        pd_free_states(pd->states, pd->state_count);
        kfree(pd->name);
        kfree(pd);
}

struct generic_pm_domain *dt_idle_pd_alloc(struct device_node *np,
                        int (*parse_state)(struct device_node *, u32 *))
{
        struct generic_pm_domain *pd;
        struct genpd_power_state *states = NULL;
        int ret, state_count = 0;

        pd = kzalloc_obj(*pd);
        if (!pd)
                goto out;

        pd->name = kasprintf(GFP_KERNEL, "%pOF", np);
        if (!pd->name)
                goto free_pd;

        /*
         * Parse the domain idle states and let genpd manage the state selection
         * for those being compatible with "domain-idle-state".
         */
        ret = pd_parse_states(np, parse_state, &states, &state_count);
        if (ret)
                goto free_name;

        pd->free_states = pd_free_states;
        pd->name = kbasename(pd->name);
        pd->states = states;
        pd->state_count = state_count;

        pr_debug("alloc PM domain %s\n", pd->name);
        return pd;

free_name:
        kfree(pd->name);
free_pd:
        kfree(pd);
out:
        pr_err("failed to alloc PM domain %pOF\n", np);
        return NULL;
}

int dt_idle_pd_init_topology(struct device_node *np)
{
        struct of_phandle_args child, parent;
        int ret;

        for_each_child_of_node_scoped(np, node) {
                if (of_parse_phandle_with_args(node, "power-domains",
                                        "#power-domain-cells", 0, &parent))
                        continue;

                child.np = node;
                child.args_count = 0;
                ret = of_genpd_add_subdomain(&parent, &child);
                of_node_put(parent.np);
                if (ret)
                        return ret;
        }

        return 0;
}

int dt_idle_pd_remove_topology(struct device_node *np)
{
        struct of_phandle_args child, parent;
        int ret;

        for_each_child_of_node_scoped(np, node) {
                if (of_parse_phandle_with_args(node, "power-domains",
                                        "#power-domain-cells", 0, &parent))
                        continue;

                child.np = node;
                child.args_count = 0;
                ret = of_genpd_remove_subdomain(&parent, &child);
                of_node_put(parent.np);
                if (ret)
                        return ret;
        }

        return 0;
}

struct device *dt_idle_attach_cpu(int cpu, const char *name)
{
        struct device *dev;

        dev = dev_pm_domain_attach_by_name(get_cpu_device(cpu), name);
        if (IS_ERR_OR_NULL(dev))
                return dev;

        pm_runtime_irq_safe(dev);
        if (cpu_online(cpu))
                pm_runtime_get_sync(dev);

        dev_pm_syscore_device(dev, true);

        return dev;
}

void dt_idle_detach_cpu(struct device *dev)
{
        if (IS_ERR_OR_NULL(dev))
                return;

        dev_pm_domain_detach(dev, false);
}