// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (c) 2015, Christoph Hellwig.
 * Copyright (c) 2015, Intel Corporation.
 */
#include <linux/platform_device.h>
#include <linux/memory_hotplug.h>
#include <linux/libnvdimm.h>
#include <linux/module.h>
#include <linux/numa.h>

static void e820_pmem_remove(struct platform_device *pdev)
{
        struct nvdimm_bus *nvdimm_bus = platform_get_drvdata(pdev);

        nvdimm_bus_unregister(nvdimm_bus);
}

static int e820_register_one(struct resource *res, void *data)
{
        struct nd_region_desc ndr_desc;
        struct nvdimm_bus *nvdimm_bus = data;
        int nid = phys_to_target_node(res->start);

        memset(&ndr_desc, 0, sizeof(ndr_desc));
        ndr_desc.res = res;
        ndr_desc.numa_node = numa_map_to_online_node(nid);
        ndr_desc.target_node = nid;
        set_bit(ND_REGION_PAGEMAP, &ndr_desc.flags);
        if (!nvdimm_pmem_region_create(nvdimm_bus, &ndr_desc))
                return -ENXIO;
        return 0;
}

static int e820_pmem_probe(struct platform_device *pdev)
{
        static struct nvdimm_bus_descriptor nd_desc;
        struct device *dev = &pdev->dev;
        struct nvdimm_bus *nvdimm_bus;
        int rc = -ENXIO;

        nd_desc.provider_name = "e820";
        nd_desc.module = THIS_MODULE;
        nvdimm_bus = nvdimm_bus_register(dev, &nd_desc);
        if (!nvdimm_bus)
                goto err;
        platform_set_drvdata(pdev, nvdimm_bus);

        rc = walk_iomem_res_desc(IORES_DESC_PERSISTENT_MEMORY_LEGACY,
                        IORESOURCE_MEM, 0, -1, nvdimm_bus, e820_register_one);
        if (rc)
                goto err;
        return 0;
err:
        nvdimm_bus_unregister(nvdimm_bus);
        dev_err(dev, "failed to register legacy persistent memory ranges\n");
        return rc;
}

static struct platform_driver e820_pmem_driver = {
        .probe = e820_pmem_probe,
        .remove = e820_pmem_remove,
        .driver = {
                .name = "e820_pmem",
        },
};

module_platform_driver(e820_pmem_driver);

MODULE_ALIAS("platform:e820_pmem*");
MODULE_DESCRIPTION("NVDIMM support for e820 type-12 memory");
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Intel Corporation");