xref: /openbmc/linux/drivers/dax/hmem/hmem.c (revision 2532f416)
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/pfn_t.h>
6 #include <linux/dax.h>
7 #include "../bus.h"
8 
9 static bool region_idle;
10 module_param_named(region_idle, region_idle, bool, 0644);
11 
dax_hmem_probe(struct platform_device * pdev)12 static int dax_hmem_probe(struct platform_device *pdev)
13 {
14 	unsigned long flags = IORESOURCE_DAX_KMEM;
15 	struct device *dev = &pdev->dev;
16 	struct dax_region *dax_region;
17 	struct memregion_info *mri;
18 	struct dev_dax_data data;
19 
20 	/*
21 	 * @region_idle == true indicates that an administrative agent
22 	 * wants to manipulate the range partitioning before the devices
23 	 * are created, so do not send them to the dax_kmem driver by
24 	 * default.
25 	 */
26 	if (region_idle)
27 		flags = 0;
28 
29 	mri = dev->platform_data;
30 	dax_region = alloc_dax_region(dev, pdev->id, &mri->range,
31 				      mri->target_node, PMD_SIZE, flags);
32 	if (!dax_region)
33 		return -ENOMEM;
34 
35 	data = (struct dev_dax_data) {
36 		.dax_region = dax_region,
37 		.id = -1,
38 		.size = region_idle ? 0 : range_len(&mri->range),
39 	};
40 
41 	return PTR_ERR_OR_ZERO(devm_create_dev_dax(&data));
42 }
43 
44 static struct platform_driver dax_hmem_driver = {
45 	.probe = dax_hmem_probe,
46 	.driver = {
47 		.name = "hmem",
48 	},
49 };
50 
release_memregion(void * data)51 static void release_memregion(void *data)
52 {
53 	memregion_free((long) data);
54 }
55 
release_hmem(void * pdev)56 static void release_hmem(void *pdev)
57 {
58 	platform_device_unregister(pdev);
59 }
60 
hmem_register_device(struct device * host,int target_nid,const struct resource * res)61 static int hmem_register_device(struct device *host, int target_nid,
62 				const struct resource *res)
63 {
64 	struct platform_device *pdev;
65 	struct memregion_info info;
66 	long id;
67 	int rc;
68 
69 	if (IS_ENABLED(CONFIG_CXL_REGION) &&
70 	    region_intersects(res->start, resource_size(res), IORESOURCE_MEM,
71 			      IORES_DESC_CXL) != REGION_DISJOINT) {
72 		dev_dbg(host, "deferring range to CXL: %pr\n", res);
73 		return 0;
74 	}
75 
76 	rc = region_intersects(res->start, resource_size(res), IORESOURCE_MEM,
77 			       IORES_DESC_SOFT_RESERVED);
78 	if (rc != REGION_INTERSECTS)
79 		return 0;
80 
81 	id = memregion_alloc(GFP_KERNEL);
82 	if (id < 0) {
83 		dev_err(host, "memregion allocation failure for %pr\n", res);
84 		return -ENOMEM;
85 	}
86 	rc = devm_add_action_or_reset(host, release_memregion, (void *) id);
87 	if (rc)
88 		return rc;
89 
90 	pdev = platform_device_alloc("hmem", id);
91 	if (!pdev) {
92 		dev_err(host, "device allocation failure for %pr\n", res);
93 		return -ENOMEM;
94 	}
95 
96 	pdev->dev.numa_node = numa_map_to_online_node(target_nid);
97 	info = (struct memregion_info) {
98 		.target_node = target_nid,
99 		.range = {
100 			.start = res->start,
101 			.end = res->end,
102 		},
103 	};
104 	rc = platform_device_add_data(pdev, &info, sizeof(info));
105 	if (rc < 0) {
106 		dev_err(host, "memregion_info allocation failure for %pr\n",
107 		       res);
108 		goto out_put;
109 	}
110 
111 	rc = platform_device_add(pdev);
112 	if (rc < 0) {
113 		dev_err(host, "%s add failed for %pr\n", dev_name(&pdev->dev),
114 			res);
115 		goto out_put;
116 	}
117 
118 	return devm_add_action_or_reset(host, release_hmem, pdev);
119 
120 out_put:
121 	platform_device_put(pdev);
122 	return rc;
123 }
124 
dax_hmem_platform_probe(struct platform_device * pdev)125 static int dax_hmem_platform_probe(struct platform_device *pdev)
126 {
127 	return walk_hmem_resources(&pdev->dev, hmem_register_device);
128 }
129 
130 static struct platform_driver dax_hmem_platform_driver = {
131 	.probe = dax_hmem_platform_probe,
132 	.driver = {
133 		.name = "hmem_platform",
134 	},
135 };
136 
dax_hmem_init(void)137 static __init int dax_hmem_init(void)
138 {
139 	int rc;
140 
141 	rc = platform_driver_register(&dax_hmem_platform_driver);
142 	if (rc)
143 		return rc;
144 
145 	rc = platform_driver_register(&dax_hmem_driver);
146 	if (rc)
147 		platform_driver_unregister(&dax_hmem_platform_driver);
148 
149 	return rc;
150 }
151 
dax_hmem_exit(void)152 static __exit void dax_hmem_exit(void)
153 {
154 	platform_driver_unregister(&dax_hmem_driver);
155 	platform_driver_unregister(&dax_hmem_platform_driver);
156 }
157 
158 module_init(dax_hmem_init);
159 module_exit(dax_hmem_exit);
160 
161 /* Allow for CXL to define its own dax regions */
162 #if IS_ENABLED(CONFIG_CXL_REGION)
163 #if IS_MODULE(CONFIG_CXL_ACPI)
164 MODULE_SOFTDEP("pre: cxl_acpi");
165 #endif
166 #endif
167 
168 MODULE_ALIAS("platform:hmem*");
169 MODULE_ALIAS("platform:hmem_platform*");
170 MODULE_LICENSE("GPL v2");
171 MODULE_AUTHOR("Intel Corporation");
172