// SPDX-License-Identifier: GPL-2.0
/*
 * SCMI Generic power domain support.
 *
 * Copyright (C) 2018-2021 ARM Ltd.
 */

#include <linux/err.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/pm_domain.h>
#include <linux/scmi_protocol.h>

static const struct scmi_power_proto_ops *power_ops;

struct scmi_pm_domain {
        struct generic_pm_domain genpd;
        const struct scmi_protocol_handle *ph;
        const char *name;
        u32 domain;
};

#define to_scmi_pd(gpd) container_of(gpd, struct scmi_pm_domain, genpd)

static int scmi_pd_power(struct generic_pm_domain *domain, u32 state)
{
        struct scmi_pm_domain *pd = to_scmi_pd(domain);

        return power_ops->state_set(pd->ph, pd->domain, state);
}

static int scmi_pd_power_on(struct generic_pm_domain *domain)
{
        return scmi_pd_power(domain, SCMI_POWER_STATE_GENERIC_ON);
}

static int scmi_pd_power_off(struct generic_pm_domain *domain)
{
        return scmi_pd_power(domain, SCMI_POWER_STATE_GENERIC_OFF);
}

static int scmi_pm_domain_probe(struct scmi_device *sdev)
{
        int num_domains, i, ret;
        struct device *dev = &sdev->dev;
        struct device_node *np = dev->of_node;
        struct scmi_pm_domain *scmi_pd;
        struct genpd_onecell_data *scmi_pd_data;
        struct generic_pm_domain **domains;
        const struct scmi_handle *handle = sdev->handle;
        struct scmi_protocol_handle *ph;

        if (!handle)
                return -ENODEV;

        power_ops = handle->devm_protocol_get(sdev, SCMI_PROTOCOL_POWER, &ph);
        if (IS_ERR(power_ops))
                return PTR_ERR(power_ops);

        num_domains = power_ops->num_domains_get(ph);
        if (num_domains < 0) {
                dev_err(dev, "number of domains not found\n");
                return num_domains;
        }

        scmi_pd = devm_kcalloc(dev, num_domains, sizeof(*scmi_pd), GFP_KERNEL);
        if (!scmi_pd)
                return -ENOMEM;

        scmi_pd_data = devm_kzalloc(dev, sizeof(*scmi_pd_data), GFP_KERNEL);
        if (!scmi_pd_data)
                return -ENOMEM;

        domains = devm_kcalloc(dev, num_domains, sizeof(*domains), GFP_KERNEL);
        if (!domains)
                return -ENOMEM;

        for (i = 0; i < num_domains; i++, scmi_pd++) {
                u32 state;

                if (power_ops->state_get(ph, i, &state)) {
                        dev_warn(dev, "failed to get state for domain %d\n", i);
                        continue;
                }

                /*
                 * Register the explicit power on request to the firmware so
                 * that it is tracked as used by OSPM agent and not
                 * accidentally turned off with OSPM's knowledge
                 */
                if (state == SCMI_POWER_STATE_GENERIC_ON)
                        power_ops->state_set(ph, i, state);

                scmi_pd->domain = i;
                scmi_pd->ph = ph;
                scmi_pd->name = power_ops->name_get(ph, i);
                scmi_pd->genpd.name = scmi_pd->name;
                scmi_pd->genpd.power_off = scmi_pd_power_off;
                scmi_pd->genpd.power_on = scmi_pd_power_on;
                scmi_pd->genpd.flags = GENPD_FLAG_ACTIVE_WAKEUP;

                pm_genpd_init(&scmi_pd->genpd, NULL,
                              state == SCMI_POWER_STATE_GENERIC_OFF);

                domains[i] = &scmi_pd->genpd;
        }

        scmi_pd_data->domains = domains;
        scmi_pd_data->num_domains = num_domains;

        ret = of_genpd_add_provider_onecell(np, scmi_pd_data);
        if (ret)
                goto err_rm_genpds;

        dev_set_drvdata(dev, scmi_pd_data);

        return 0;
err_rm_genpds:
        for (i = num_domains - 1; i >= 0; i--)
                pm_genpd_remove(domains[i]);

        return ret;
}

static void scmi_pm_domain_remove(struct scmi_device *sdev)
{
        int i;
        struct genpd_onecell_data *scmi_pd_data;
        struct device *dev = &sdev->dev;
        struct device_node *np = dev->of_node;

        of_genpd_del_provider(np);

        scmi_pd_data = dev_get_drvdata(dev);
        for (i = 0; i < scmi_pd_data->num_domains; i++) {
                if (!scmi_pd_data->domains[i])
                        continue;
                pm_genpd_remove(scmi_pd_data->domains[i]);
        }
}

static const struct scmi_device_id scmi_id_table[] = {
        { SCMI_PROTOCOL_POWER, "genpd" },
        { },
};
MODULE_DEVICE_TABLE(scmi, scmi_id_table);

static struct scmi_driver scmi_power_domain_driver = {
        .name = "scmi-power-domain",
        .probe = scmi_pm_domain_probe,
        .remove = scmi_pm_domain_remove,
        .id_table = scmi_id_table,
};
module_scmi_driver(scmi_power_domain_driver);

MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
MODULE_DESCRIPTION("ARM SCMI power domain driver");
MODULE_LICENSE("GPL v2");