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 .memmap_on_memory = false,
40 };
41
42 return PTR_ERR_OR_ZERO(devm_create_dev_dax(&data));
43 }
44
45 static struct platform_driver dax_hmem_driver = {
46 .probe = dax_hmem_probe,
47 .driver = {
48 .name = "hmem",
49 },
50 };
51
release_memregion(void * data)52 static void release_memregion(void *data)
53 {
54 memregion_free((long) data);
55 }
56
release_hmem(void * pdev)57 static void release_hmem(void *pdev)
58 {
59 platform_device_unregister(pdev);
60 }
61
hmem_register_device(struct device * host,int target_nid,const struct resource * res)62 static int hmem_register_device(struct device *host, int target_nid,
63 const struct resource *res)
64 {
65 struct platform_device *pdev;
66 struct memregion_info info;
67 long id;
68 int rc;
69
70 if (IS_ENABLED(CONFIG_CXL_REGION) &&
71 region_intersects(res->start, resource_size(res), IORESOURCE_MEM,
72 IORES_DESC_CXL) != REGION_DISJOINT) {
73 dev_dbg(host, "deferring range to CXL: %pr\n", res);
74 return 0;
75 }
76
77 rc = region_intersects(res->start, resource_size(res), IORESOURCE_MEM,
78 IORES_DESC_SOFT_RESERVED);
79 if (rc != REGION_INTERSECTS)
80 return 0;
81
82 id = memregion_alloc(GFP_KERNEL);
83 if (id < 0) {
84 dev_err(host, "memregion allocation failure for %pr\n", res);
85 return -ENOMEM;
86 }
87 rc = devm_add_action_or_reset(host, release_memregion, (void *) id);
88 if (rc)
89 return rc;
90
91 pdev = platform_device_alloc("hmem", id);
92 if (!pdev) {
93 dev_err(host, "device allocation failure for %pr\n", res);
94 return -ENOMEM;
95 }
96
97 pdev->dev.numa_node = numa_map_to_online_node(target_nid);
98 info = (struct memregion_info) {
99 .target_node = target_nid,
100 .range = {
101 .start = res->start,
102 .end = res->end,
103 },
104 };
105 rc = platform_device_add_data(pdev, &info, sizeof(info));
106 if (rc < 0) {
107 dev_err(host, "memregion_info allocation failure for %pr\n",
108 res);
109 goto out_put;
110 }
111
112 rc = platform_device_add(pdev);
113 if (rc < 0) {
114 dev_err(host, "%s add failed for %pr\n", dev_name(&pdev->dev),
115 res);
116 goto out_put;
117 }
118
119 return devm_add_action_or_reset(host, release_hmem, pdev);
120
121 out_put:
122 platform_device_put(pdev);
123 return rc;
124 }
125
dax_hmem_platform_probe(struct platform_device * pdev)126 static int dax_hmem_platform_probe(struct platform_device *pdev)
127 {
128 return walk_hmem_resources(&pdev->dev, hmem_register_device);
129 }
130
131 static struct platform_driver dax_hmem_platform_driver = {
132 .probe = dax_hmem_platform_probe,
133 .driver = {
134 .name = "hmem_platform",
135 },
136 };
137
dax_hmem_init(void)138 static __init int dax_hmem_init(void)
139 {
140 int rc;
141
142 rc = platform_driver_register(&dax_hmem_platform_driver);
143 if (rc)
144 return rc;
145
146 rc = platform_driver_register(&dax_hmem_driver);
147 if (rc)
148 platform_driver_unregister(&dax_hmem_platform_driver);
149
150 return rc;
151 }
152
dax_hmem_exit(void)153 static __exit void dax_hmem_exit(void)
154 {
155 platform_driver_unregister(&dax_hmem_driver);
156 platform_driver_unregister(&dax_hmem_platform_driver);
157 }
158
159 module_init(dax_hmem_init);
160 module_exit(dax_hmem_exit);
161
162 /* Allow for CXL to define its own dax regions */
163 #if IS_ENABLED(CONFIG_CXL_REGION)
164 #if IS_MODULE(CONFIG_CXL_ACPI)
165 MODULE_SOFTDEP("pre: cxl_acpi");
166 #endif
167 #endif
168
169 MODULE_ALIAS("platform:hmem*");
170 MODULE_ALIAS("platform:hmem_platform*");
171 MODULE_DESCRIPTION("HMEM DAX: direct access to 'specific purpose' memory");
172 MODULE_LICENSE("GPL v2");
173 MODULE_AUTHOR("Intel Corporation");
174