// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) IoT.bzh 2021
 */

#include <linux/limits.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_reserved_mem.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/remoteproc.h>
#include <linux/reset.h>
#include <linux/soc/renesas/rcar-rst.h>

#include "remoteproc_internal.h"

struct rcar_rproc {
        struct reset_control *rst;
};

static int rcar_rproc_mem_alloc(struct rproc *rproc,
                                 struct rproc_mem_entry *mem)
{
        struct device *dev = &rproc->dev;
        void *va;

        dev_dbg(dev, "map memory: %pa+%zx\n", &mem->dma, mem->len);
        va = ioremap_wc(mem->dma, mem->len);
        if (!va) {
                dev_err(dev, "Unable to map memory region: %pa+%zx\n",
                        &mem->dma, mem->len);
                return -ENOMEM;
        }

        /* Update memory entry va */
        mem->va = va;

        return 0;
}

static int rcar_rproc_mem_release(struct rproc *rproc,
                                   struct rproc_mem_entry *mem)
{
        dev_dbg(&rproc->dev, "unmap memory: %pa\n", &mem->dma);
        iounmap(mem->va);

        return 0;
}

static int rcar_rproc_prepare(struct rproc *rproc)
{
        struct device *dev = rproc->dev.parent;
        struct device_node *np = dev->of_node;
        struct rproc_mem_entry *mem;
        int i = 0;
        u32 da;

        /* Register associated reserved memory regions */
        while (1) {
                struct resource res;
                int ret;

                ret = of_reserved_mem_region_to_resource(np, i++, &res);
                if (ret)
                        return 0;

                if (res.start > U32_MAX)
                        return -EINVAL;

                /* No need to translate pa to da, R-Car use same map */
                da = res.start;
                mem = rproc_mem_entry_init(dev, NULL,
                                           res.start,
                                           resource_size(&res), da,
                                           rcar_rproc_mem_alloc,
                                           rcar_rproc_mem_release,
                                           res.name);

                if (!mem)
                        return -ENOMEM;

                rproc_add_carveout(rproc, mem);
        }
}

static int rcar_rproc_parse_fw(struct rproc *rproc, const struct firmware *fw)
{
        int ret;

        ret = rproc_elf_load_rsc_table(rproc, fw);
        if (ret)
                dev_info(&rproc->dev, "No resource table in elf\n");

        return 0;
}

static int rcar_rproc_start(struct rproc *rproc)
{
        struct rcar_rproc *priv = rproc->priv;
        int err;

        if (!rproc->bootaddr)
                return -EINVAL;

        err = rcar_rst_set_rproc_boot_addr(rproc->bootaddr);
        if (err) {
                dev_err(&rproc->dev, "failed to set rproc boot addr\n");
                return err;
        }

        err = reset_control_deassert(priv->rst);
        if (err)
                dev_err(&rproc->dev, "failed to deassert reset\n");

        return err;
}

static int rcar_rproc_stop(struct rproc *rproc)
{
        struct rcar_rproc *priv = rproc->priv;
        int err;

        err = reset_control_assert(priv->rst);
        if (err)
                dev_err(&rproc->dev, "failed to assert reset\n");

        return err;
}

static struct rproc_ops rcar_rproc_ops = {
        .prepare        = rcar_rproc_prepare,
        .start          = rcar_rproc_start,
        .stop           = rcar_rproc_stop,
        .load           = rproc_elf_load_segments,
        .parse_fw       = rcar_rproc_parse_fw,
        .find_loaded_rsc_table = rproc_elf_find_loaded_rsc_table,
        .sanity_check   = rproc_elf_sanity_check,
        .get_boot_addr  = rproc_elf_get_boot_addr,

};

static int rcar_rproc_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct device_node *np = dev->of_node;
        struct rcar_rproc *priv;
        struct rproc *rproc;
        int ret;

        rproc = devm_rproc_alloc(dev, np->name, &rcar_rproc_ops,
                                NULL, sizeof(*priv));
        if (!rproc)
                return -ENOMEM;

        priv = rproc->priv;

        priv->rst = devm_reset_control_get_exclusive(dev, NULL);
        if (IS_ERR(priv->rst)) {
                ret = PTR_ERR(priv->rst);
                dev_err_probe(dev, ret, "fail to acquire rproc reset\n");
                return ret;
        }

        pm_runtime_enable(dev);
        ret = pm_runtime_resume_and_get(dev);
        if (ret) {
                dev_err(dev, "failed to power up\n");
                return ret;
        }

        dev_set_drvdata(dev, rproc);

        /* Manually start the rproc */
        rproc->auto_boot = false;

        ret = devm_rproc_add(dev, rproc);
        if (ret) {
                dev_err(dev, "rproc_add failed\n");
                goto pm_disable;
        }

        return 0;

pm_disable:
        pm_runtime_disable(dev);

        return ret;
}

static void rcar_rproc_remove(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;

        pm_runtime_disable(dev);
}

static const struct of_device_id rcar_rproc_of_match[] = {
        { .compatible = "renesas,rcar-cr7" },
        {},
};

MODULE_DEVICE_TABLE(of, rcar_rproc_of_match);

static struct platform_driver rcar_rproc_driver = {
        .probe = rcar_rproc_probe,
        .remove = rcar_rproc_remove,
        .driver = {
                .name = "rcar-rproc",
                .of_match_table = rcar_rproc_of_match,
        },
};

module_platform_driver(rcar_rproc_driver);

MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("Renesas R-Car Gen3 remote processor control driver");
MODULE_AUTHOR("Julien Massot <julien.massot@iot.bzh>");