// 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 int e820_pmem_remove(struct platform_device *pdev)
  {
  	struct nvdimm_bus *nvdimm_bus = platform_get_drvdata(pdev);
  
  	nvdimm_bus_unregister(nvdimm_bus);
  	return 0;
  }

  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
  ");

  	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_LICENSE("GPL v2");
  MODULE_AUTHOR("Intel Corporation");