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
9static bool region_idle;
10module_param_named(region_idle, region_idle, bool, 0644);
11
12static 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(parent: dev, region_id: pdev->id, range: &mri->range,
31 target_node: 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(range: &mri->range),
39 .memmap_on_memory = false,
40 };
41
42 return PTR_ERR_OR_ZERO(ptr: devm_create_dev_dax(data: &data));
43}
44
45static struct platform_driver dax_hmem_driver = {
46 .probe = dax_hmem_probe,
47 .driver = {
48 .name = "hmem",
49 },
50};
51
52static void release_memregion(void *data)
53{
54 memregion_free(id: (long) data);
55}
56
57static void release_hmem(void *pdev)
58{
59 platform_device_unregister(pdev);
60}
61
62static 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(offset: res->start, size: resource_size(res), IORESOURCE_MEM,
72 desc: 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(offset: res->start, size: resource_size(res), IORESOURCE_MEM,
78 desc: 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(name: "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, data: &info, size: 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
121out_put:
122 platform_device_put(pdev);
123 return rc;
124}
125
126static int dax_hmem_platform_probe(struct platform_device *pdev)
127{
128 return walk_hmem_resources(dev: &pdev->dev, fn: hmem_register_device);
129}
130
131static struct platform_driver dax_hmem_platform_driver = {
132 .probe = dax_hmem_platform_probe,
133 .driver = {
134 .name = "hmem_platform",
135 },
136};
137
138static __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
153static __exit void dax_hmem_exit(void)
154{
155 platform_driver_unregister(&dax_hmem_driver);
156 platform_driver_unregister(&dax_hmem_platform_driver);
157}
158
159module_init(dax_hmem_init);
160module_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)
165MODULE_SOFTDEP("pre: cxl_acpi");
166#endif
167#endif
168
169MODULE_ALIAS("platform:hmem*");
170MODULE_ALIAS("platform:hmem_platform*");
171MODULE_LICENSE("GPL v2");
172MODULE_AUTHOR("Intel Corporation");
173

source code of linux/drivers/dax/hmem/hmem.c