1 // SPDX-License-Identifier: GPL-2.0
2 #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 
8 static bool nohmem;
9 module_param_named(disable, nohmem, bool, 0444);
10 
hmem_register_device(int target_nid,struct resource * r)11 void hmem_register_device(int target_nid, struct resource *r)
12 {
13 	/* define a clean / non-busy resource for the platform device */
14 	struct resource res = {
15 		.start = r->start,
16 		.end = r->end,
17 		.flags = IORESOURCE_MEM,
18 	};
19 	struct platform_device *pdev;
20 	struct memregion_info info;
21 	int rc, id;
22 
23 	if (nohmem)
24 		return;
25 
26 	rc = region_intersects(res.start, resource_size(&res), IORESOURCE_MEM,
27 			IORES_DESC_SOFT_RESERVED);
28 	if (rc != REGION_INTERSECTS)
29 		return;
30 
31 	id = memregion_alloc(GFP_KERNEL);
32 	if (id < 0) {
33 		pr_err("memregion allocation failure for %pr\n", &res);
34 		return;
35 	}
36 
37 	pdev = platform_device_alloc("hmem", id);
38 	if (!pdev) {
39 		pr_err("hmem device allocation failure for %pr\n", &res);
40 		goto out_pdev;
41 	}
42 
43 	pdev->dev.numa_node = numa_map_to_online_node(target_nid);
44 	info = (struct memregion_info) {
45 		.target_node = target_nid,
46 	};
47 	rc = platform_device_add_data(pdev, &info, sizeof(info));
48 	if (rc < 0) {
49 		pr_err("hmem memregion_info allocation failure for %pr\n", &res);
50 		goto out_pdev;
51 	}
52 
53 	rc = platform_device_add_resources(pdev, &res, 1);
54 	if (rc < 0) {
55 		pr_err("hmem resource allocation failure for %pr\n", &res);
56 		goto out_resource;
57 	}
58 
59 	rc = platform_device_add(pdev);
60 	if (rc < 0) {
61 		dev_err(&pdev->dev, "device add failed for %pr\n", &res);
62 		goto out_resource;
63 	}
64 
65 	return;
66 
67 out_resource:
68 	put_device(&pdev->dev);
69 out_pdev:
70 	memregion_free(id);
71 }
72 
hmem_register_one(struct resource * res,void * data)73 static __init int hmem_register_one(struct resource *res, void *data)
74 {
75 	/*
76 	 * If the resource is not a top-level resource it was already
77 	 * assigned to a device by the HMAT parsing.
78 	 */
79 	if (res->parent != &iomem_resource) {
80 		pr_info("HMEM: skip %pr, already claimed\n", res);
81 		return 0;
82 	}
83 
84 	hmem_register_device(phys_to_target_node(res->start), res);
85 
86 	return 0;
87 }
88 
hmem_init(void)89 static __init int hmem_init(void)
90 {
91 	walk_iomem_res_desc(IORES_DESC_SOFT_RESERVED,
92 			IORESOURCE_MEM, 0, -1, NULL, hmem_register_one);
93 	return 0;
94 }
95 
96 /*
97  * As this is a fallback for address ranges unclaimed by the ACPI HMAT
98  * parsing it must be at an initcall level greater than hmat_init().
99  */
100 late_initcall(hmem_init);
101