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1// SPDX-License-Identifier: GPL-2.02#include <linux/platform_device.h>3#include <linux/memregion.h>4#include <linux/module.h>5#include <linux/dax.h>6#include <linux/mm.h>7 8static bool nohmem;9module_param_named(disable, nohmem, bool, 0444);10 11static bool platform_initialized;12static DEFINE_MUTEX(hmem_resource_lock);13static struct resource hmem_active = {14 .name = "HMEM devices",15 .start = 0,16 .end = -1,17 .flags = IORESOURCE_MEM,18};19 20int walk_hmem_resources(struct device *host, walk_hmem_fn fn)21{22 struct resource *res;23 int rc = 0;24 25 mutex_lock(&hmem_resource_lock);26 for (res = hmem_active.child; res; res = res->sibling) {27 rc = fn(host, (int) res->desc, res);28 if (rc)29 break;30 }31 mutex_unlock(&hmem_resource_lock);32 return rc;33}34EXPORT_SYMBOL_GPL(walk_hmem_resources);35 36static void __hmem_register_resource(int target_nid, struct resource *res)37{38 struct platform_device *pdev;39 struct resource *new;40 int rc;41 42 new = __request_region(&hmem_active, res->start, resource_size(res), "",43 0);44 if (!new) {45 pr_debug("hmem range %pr already active\n", res);46 return;47 }48 49 new->desc = target_nid;50 51 if (platform_initialized)52 return;53 54 pdev = platform_device_alloc("hmem_platform", 0);55 if (!pdev) {56 pr_err_once("failed to register device-dax hmem_platform device\n");57 return;58 }59 60 rc = platform_device_add(pdev);61 if (rc)62 platform_device_put(pdev);63 else64 platform_initialized = true;65}66 67void hmem_register_resource(int target_nid, struct resource *res)68{69 if (nohmem)70 return;71 72 mutex_lock(&hmem_resource_lock);73 __hmem_register_resource(target_nid, res);74 mutex_unlock(&hmem_resource_lock);75}76 77static __init int hmem_register_one(struct resource *res, void *data)78{79 hmem_register_resource(phys_to_target_node(res->start), res);80 81 return 0;82}83 84static __init int hmem_init(void)85{86 walk_iomem_res_desc(IORES_DESC_SOFT_RESERVED,87 IORESOURCE_MEM, 0, -1, NULL, hmem_register_one);88 return 0;89}90 91/*92 * As this is a fallback for address ranges unclaimed by the ACPI HMAT93 * parsing it must be at an initcall level greater than hmat_init().94 */95device_initcall(hmem_init);96