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 	struct dev_dax *dev_dax;
20 
21 	/*
22 	 * @region_idle == true indicates that an administrative agent
23 	 * wants to manipulate the range partitioning before the devices
24 	 * are created, so do not send them to the dax_kmem driver by
25 	 * default.
26 	 */
27 	if (region_idle)
28 		flags = 0;
29 
30 	mri = dev->platform_data;
31 	dax_region = alloc_dax_region(dev, pdev->id, &mri->range,
32 				      mri->target_node, PMD_SIZE, flags);
33 	if (!dax_region)
34 		return -ENOMEM;
35 
36 	data = (struct dev_dax_data) {
37 		.dax_region = dax_region,
38 		.id = -1,
39 		.size = region_idle ? 0 : range_len(&mri->range),
40 	};
41 	dev_dax = devm_create_dev_dax(&data);
42 	if (IS_ERR(dev_dax))
43 		return PTR_ERR(dev_dax);
44 
45 	/* child dev_dax instances now own the lifetime of the dax_region */
46 	dax_region_put(dax_region);
47 	return 0;
48 }
49 
50 static struct platform_driver dax_hmem_driver = {
51 	.probe = dax_hmem_probe,
52 	.driver = {
53 		.name = "hmem",
54 	},
55 };
56 
release_memregion(void * data)57 static void release_memregion(void *data)
58 {
59 	memregion_free((long) data);
60 }
61 
release_hmem(void * pdev)62 static void release_hmem(void *pdev)
63 {
64 	platform_device_unregister(pdev);
65 }
66 
hmem_register_device(struct device * host,int target_nid,const struct resource * res)67 static int hmem_register_device(struct device *host, int target_nid,
68 				const struct resource *res)
69 {
70 	struct platform_device *pdev;
71 	struct memregion_info info;
72 	long id;
73 	int rc;
74 
75 	if (IS_ENABLED(CONFIG_CXL_REGION) &&
76 	    region_intersects(res->start, resource_size(res), IORESOURCE_MEM,
77 			      IORES_DESC_CXL) != REGION_DISJOINT) {
78 		dev_dbg(host, "deferring range to CXL: %pr\n", res);
79 		return 0;
80 	}
81 
82 	rc = region_intersects(res->start, resource_size(res), IORESOURCE_MEM,
83 			       IORES_DESC_SOFT_RESERVED);
84 	if (rc != REGION_INTERSECTS)
85 		return 0;
86 
87 	id = memregion_alloc(GFP_KERNEL);
88 	if (id < 0) {
89 		dev_err(host, "memregion allocation failure for %pr\n", res);
90 		return -ENOMEM;
91 	}
92 	rc = devm_add_action_or_reset(host, release_memregion, (void *) id);
93 	if (rc)
94 		return rc;
95 
96 	pdev = platform_device_alloc("hmem", id);
97 	if (!pdev) {
98 		dev_err(host, "device allocation failure for %pr\n", res);
99 		return -ENOMEM;
100 	}
101 
102 	pdev->dev.numa_node = numa_map_to_online_node(target_nid);
103 	info = (struct memregion_info) {
104 		.target_node = target_nid,
105 		.range = {
106 			.start = res->start,
107 			.end = res->end,
108 		},
109 	};
110 	rc = platform_device_add_data(pdev, &info, sizeof(info));
111 	if (rc < 0) {
112 		dev_err(host, "memregion_info allocation failure for %pr\n",
113 		       res);
114 		goto out_put;
115 	}
116 
117 	rc = platform_device_add(pdev);
118 	if (rc < 0) {
119 		dev_err(host, "%s add failed for %pr\n", dev_name(&pdev->dev),
120 			res);
121 		goto out_put;
122 	}
123 
124 	return devm_add_action_or_reset(host, release_hmem, pdev);
125 
126 out_put:
127 	platform_device_put(pdev);
128 	return rc;
129 }
130 
dax_hmem_platform_probe(struct platform_device * pdev)131 static int dax_hmem_platform_probe(struct platform_device *pdev)
132 {
133 	return walk_hmem_resources(&pdev->dev, hmem_register_device);
134 }
135 
136 static struct platform_driver dax_hmem_platform_driver = {
137 	.probe = dax_hmem_platform_probe,
138 	.driver = {
139 		.name = "hmem_platform",
140 	},
141 };
142 
dax_hmem_init(void)143 static __init int dax_hmem_init(void)
144 {
145 	int rc;
146 
147 	rc = platform_driver_register(&dax_hmem_platform_driver);
148 	if (rc)
149 		return rc;
150 
151 	rc = platform_driver_register(&dax_hmem_driver);
152 	if (rc)
153 		platform_driver_unregister(&dax_hmem_platform_driver);
154 
155 	return rc;
156 }
157 
dax_hmem_exit(void)158 static __exit void dax_hmem_exit(void)
159 {
160 	platform_driver_unregister(&dax_hmem_driver);
161 	platform_driver_unregister(&dax_hmem_platform_driver);
162 }
163 
164 module_init(dax_hmem_init);
165 module_exit(dax_hmem_exit);
166 
167 /* Allow for CXL to define its own dax regions */
168 #if IS_ENABLED(CONFIG_CXL_REGION)
169 #if IS_MODULE(CONFIG_CXL_ACPI)
170 MODULE_SOFTDEP("pre: cxl_acpi");
171 #endif
172 #endif
173 
174 MODULE_ALIAS("platform:hmem*");
175 MODULE_ALIAS("platform:hmem_platform*");
176 MODULE_LICENSE("GPL v2");
177 MODULE_AUTHOR("Intel Corporation");
178