// SPDX-License-Identifier: GPL-2.0-only
/*
 * Exynos generic interconnect provider driver
 *
 * Copyright (c) 2020 Samsung Electronics Co., Ltd.
 *
 * Authors: Artur Świgoń <a.swigon@samsung.com>
 *          Sylwester Nawrocki <s.nawrocki@samsung.com>
 */
#include <linux/device.h>
#include <linux/interconnect-provider.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/pm_qos.h>
#include <linux/slab.h>

#define EXYNOS_ICC_DEFAULT_BUS_CLK_RATIO        8

struct exynos_icc_priv {
        struct device *dev;

        /* One interconnect node per provider */
        struct icc_provider provider;
        struct icc_node *node;

        struct dev_pm_qos_request qos_req;
        u32 bus_clk_ratio;
};

static struct icc_node *exynos_icc_get_parent(struct device_node *np)
{
        struct of_phandle_args args;
        struct icc_node_data *icc_node_data;
        struct icc_node *icc_node;
        int num, ret;

        num = of_count_phandle_with_args(np, "interconnects",
                                         "#interconnect-cells");
        if (num < 1)
                return NULL; /* parent nodes are optional */

        /* Get the interconnect target node */
        ret = of_parse_phandle_with_args(np, "interconnects",
                                        "#interconnect-cells", 0, &args);
        if (ret < 0)
                return ERR_PTR(ret);

        icc_node_data = of_icc_get_from_provider(&args);
        of_node_put(args.np);

        if (IS_ERR(icc_node_data))
                return ERR_CAST(icc_node_data);

        icc_node = icc_node_data->node;
        kfree(icc_node_data);

        return icc_node;
}

static int exynos_generic_icc_set(struct icc_node *src, struct icc_node *dst)
{
        struct exynos_icc_priv *src_priv = src->data, *dst_priv = dst->data;
        s32 src_freq = max(src->avg_bw, src->peak_bw) / src_priv->bus_clk_ratio;
        s32 dst_freq = max(dst->avg_bw, dst->peak_bw) / dst_priv->bus_clk_ratio;
        int ret;

        ret = dev_pm_qos_update_request(&src_priv->qos_req, src_freq);
        if (ret < 0) {
                dev_err(src_priv->dev, "failed to update PM QoS of %s (src)\n",
                        src->name);
                return ret;
        }

        ret = dev_pm_qos_update_request(&dst_priv->qos_req, dst_freq);
        if (ret < 0) {
                dev_err(dst_priv->dev, "failed to update PM QoS of %s (dst)\n",
                        dst->name);
                return ret;
        }

        return 0;
}

static struct icc_node *exynos_generic_icc_xlate(const struct of_phandle_args *spec,
                                                 void *data)
{
        struct exynos_icc_priv *priv = data;

        if (spec->np != priv->dev->parent->of_node)
                return ERR_PTR(-EINVAL);

        return priv->node;
}

static void exynos_generic_icc_remove(struct platform_device *pdev)
{
        struct exynos_icc_priv *priv = platform_get_drvdata(pdev);

        icc_provider_deregister(&priv->provider);
        icc_nodes_remove(&priv->provider);
}

static int exynos_generic_icc_probe(struct platform_device *pdev)
{
        struct device *bus_dev = pdev->dev.parent;
        struct exynos_icc_priv *priv;
        struct icc_provider *provider;
        struct icc_node *icc_node, *icc_parent_node;
        int ret;

        priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
        if (!priv)
                return -ENOMEM;

        priv->dev = &pdev->dev;
        platform_set_drvdata(pdev, priv);

        provider = &priv->provider;

        provider->set = exynos_generic_icc_set;
        provider->aggregate = icc_std_aggregate;
        provider->xlate = exynos_generic_icc_xlate;
        provider->dev = bus_dev;
        provider->inter_set = true;
        provider->data = priv;

        icc_provider_init(provider);

        icc_node = icc_node_create(pdev->id);
        if (IS_ERR(icc_node))
                return PTR_ERR(icc_node);

        priv->node = icc_node;
        icc_node->name = devm_kasprintf(&pdev->dev, GFP_KERNEL, "%pOFn",
                                        bus_dev->of_node);
        if (!icc_node->name) {
                icc_node_destroy(pdev->id);
                return -ENOMEM;
        }

        if (of_property_read_u32(bus_dev->of_node, "samsung,data-clock-ratio",
                                 &priv->bus_clk_ratio))
                priv->bus_clk_ratio = EXYNOS_ICC_DEFAULT_BUS_CLK_RATIO;

        icc_node->data = priv;
        icc_node_add(icc_node, provider);

        /*
         * Register a PM QoS request for the parent (devfreq) device.
         */
        ret = dev_pm_qos_add_request(bus_dev, &priv->qos_req,
                                     DEV_PM_QOS_MIN_FREQUENCY, 0);
        if (ret < 0)
                goto err_node_del;

        icc_parent_node = exynos_icc_get_parent(bus_dev->of_node);
        if (IS_ERR(icc_parent_node)) {
                ret = PTR_ERR(icc_parent_node);
                goto err_pmqos_del;
        }
        if (icc_parent_node) {
                ret = icc_link_create(icc_node, icc_parent_node->id);
                if (ret < 0)
                        goto err_pmqos_del;
        }

        ret = icc_provider_register(provider);
        if (ret < 0)
                goto err_pmqos_del;

        return 0;

err_pmqos_del:
        dev_pm_qos_remove_request(&priv->qos_req);
err_node_del:
        icc_nodes_remove(provider);

        return ret;
}

static struct platform_driver exynos_generic_icc_driver = {
        .driver = {
                .name = "exynos-generic-icc",
                .sync_state = icc_sync_state,
        },
        .probe = exynos_generic_icc_probe,
        .remove = exynos_generic_icc_remove,
};
module_platform_driver(exynos_generic_icc_driver);

MODULE_DESCRIPTION("Exynos generic interconnect driver");
MODULE_AUTHOR("Artur Świgoń <a.swigon@samsung.com>");
MODULE_AUTHOR("Sylwester Nawrocki <s.nawrocki@samsung.com>");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:exynos-generic-icc");