// SPDX-License-Identifier: GPL-2.0+

#define pr_fmt(fmt) "of_pmem: " fmt

#include <linux/of.h>
#include <linux/libnvdimm.h>
#include <linux/module.h>
#include <linux/ioport.h>
#include <linux/platform_device.h>
#include <linux/slab.h>

struct of_pmem_private {
        struct nvdimm_bus_descriptor bus_desc;
        struct nvdimm_bus *bus;
};

static int of_pmem_region_probe(struct platform_device *pdev)
{
        struct of_pmem_private *priv;
        struct device_node *np;
        struct nvdimm_bus *bus;
        bool is_volatile;
        int i;

        np = dev_of_node(&pdev->dev);
        if (!np)
                return -ENXIO;

        priv = kzalloc_obj(*priv);
        if (!priv)
                return -ENOMEM;

        priv->bus_desc.provider_name = devm_kstrdup(&pdev->dev, pdev->name,
                                                        GFP_KERNEL);
        if (!priv->bus_desc.provider_name) {
                kfree(priv);
                return -ENOMEM;
        }

        priv->bus_desc.module = THIS_MODULE;
        priv->bus_desc.of_node = np;

        priv->bus = bus = nvdimm_bus_register(&pdev->dev, &priv->bus_desc);
        if (!bus) {
                kfree(priv);
                return -ENODEV;
        }
        platform_set_drvdata(pdev, priv);

        is_volatile = of_property_read_bool(np, "volatile");
        dev_dbg(&pdev->dev, "Registering %s regions from %pOF\n",
                        is_volatile ? "volatile" : "non-volatile",  np);

        for (i = 0; i < pdev->num_resources; i++) {
                struct nd_region_desc ndr_desc;
                struct nd_region *region;

                /*
                 * NB: libnvdimm copies the data from ndr_desc into it's own
                 * structures so passing a stack pointer is fine.
                 */
                memset(&ndr_desc, 0, sizeof(ndr_desc));
                ndr_desc.numa_node = dev_to_node(&pdev->dev);
                ndr_desc.target_node = ndr_desc.numa_node;
                ndr_desc.res = &pdev->resource[i];
                ndr_desc.of_node = np;
                set_bit(ND_REGION_PAGEMAP, &ndr_desc.flags);

                if (is_volatile)
                        region = nvdimm_volatile_region_create(bus, &ndr_desc);
                else {
                        set_bit(ND_REGION_PERSIST_MEMCTRL, &ndr_desc.flags);
                        region = nvdimm_pmem_region_create(bus, &ndr_desc);
                }

                if (!region)
                        dev_warn(&pdev->dev, "Unable to register region %pR from %pOF\n",
                                        ndr_desc.res, np);
                else
                        dev_dbg(&pdev->dev, "Registered region %pR from %pOF\n",
                                        ndr_desc.res, np);
        }

        return 0;
}

static void of_pmem_region_remove(struct platform_device *pdev)
{
        struct of_pmem_private *priv = platform_get_drvdata(pdev);

        nvdimm_bus_unregister(priv->bus);
        kfree(priv);
}

static const struct of_device_id of_pmem_region_match[] = {
        { .compatible = "pmem-region" },
        { .compatible = "pmem-region-v2" },
        { },
};

static struct platform_driver of_pmem_region_driver = {
        .probe = of_pmem_region_probe,
        .remove = of_pmem_region_remove,
        .driver = {
                .name = "of_pmem",
                .of_match_table = of_pmem_region_match,
        },
};

module_platform_driver(of_pmem_region_driver);
MODULE_DEVICE_TABLE(of, of_pmem_region_match);
MODULE_DESCRIPTION("NVDIMM Device Tree support");
MODULE_LICENSE("GPL");
MODULE_AUTHOR("IBM Corporation");