xref: /openbmc/linux/drivers/dax/pmem.c (revision 234489ac)
1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright(c) 2016 - 2018 Intel Corporation. All rights reserved. */
3 #include <linux/memremap.h>
4 #include <linux/module.h>
5 #include <linux/pfn_t.h>
6 #include "../nvdimm/pfn.h"
7 #include "../nvdimm/nd.h"
8 #include "bus.h"
9 
10 static struct dev_dax *__dax_pmem_probe(struct device *dev)
11 {
12 	struct range range;
13 	int rc, id, region_id;
14 	resource_size_t offset;
15 	struct nd_pfn_sb *pfn_sb;
16 	struct dev_dax *dev_dax;
17 	struct dev_dax_data data;
18 	struct nd_namespace_io *nsio;
19 	struct dax_region *dax_region;
20 	struct dev_pagemap pgmap = { };
21 	struct nd_namespace_common *ndns;
22 	struct nd_dax *nd_dax = to_nd_dax(dev);
23 	struct nd_pfn *nd_pfn = &nd_dax->nd_pfn;
24 	struct nd_region *nd_region = to_nd_region(dev->parent);
25 
26 	ndns = nvdimm_namespace_common_probe(dev);
27 	if (IS_ERR(ndns))
28 		return ERR_CAST(ndns);
29 
30 	/* parse the 'pfn' info block via ->rw_bytes */
31 	rc = devm_namespace_enable(dev, ndns, nd_info_block_reserve());
32 	if (rc)
33 		return ERR_PTR(rc);
34 	rc = nvdimm_setup_pfn(nd_pfn, &pgmap);
35 	if (rc)
36 		return ERR_PTR(rc);
37 	devm_namespace_disable(dev, ndns);
38 
39 	/* reserve the metadata area, device-dax will reserve the data */
40 	pfn_sb = nd_pfn->pfn_sb;
41 	offset = le64_to_cpu(pfn_sb->dataoff);
42 	nsio = to_nd_namespace_io(&ndns->dev);
43 	if (!devm_request_mem_region(dev, nsio->res.start, offset,
44 				dev_name(&ndns->dev))) {
45 		dev_warn(dev, "could not reserve metadata\n");
46 		return ERR_PTR(-EBUSY);
47 	}
48 
49 	rc = sscanf(dev_name(&ndns->dev), "namespace%d.%d", &region_id, &id);
50 	if (rc != 2)
51 		return ERR_PTR(-EINVAL);
52 
53 	/* adjust the dax_region range to the start of data */
54 	range = pgmap.range;
55 	range.start += offset;
56 	dax_region = alloc_dax_region(dev, region_id, &range,
57 			nd_region->target_node, le32_to_cpu(pfn_sb->align),
58 			IORESOURCE_DAX_STATIC);
59 	if (!dax_region)
60 		return ERR_PTR(-ENOMEM);
61 
62 	data = (struct dev_dax_data) {
63 		.dax_region = dax_region,
64 		.id = id,
65 		.pgmap = &pgmap,
66 		.size = range_len(&range),
67 	};
68 	dev_dax = devm_create_dev_dax(&data);
69 
70 	/* child dev_dax instances now own the lifetime of the dax_region */
71 	dax_region_put(dax_region);
72 
73 	return dev_dax;
74 }
75 
76 static int dax_pmem_probe(struct device *dev)
77 {
78 	return PTR_ERR_OR_ZERO(__dax_pmem_probe(dev));
79 }
80 
81 static struct nd_device_driver dax_pmem_driver = {
82 	.probe = dax_pmem_probe,
83 	.drv = {
84 		.name = "dax_pmem",
85 	},
86 	.type = ND_DRIVER_DAX_PMEM,
87 };
88 
89 static int __init dax_pmem_init(void)
90 {
91 	return nd_driver_register(&dax_pmem_driver);
92 }
93 module_init(dax_pmem_init);
94 
95 static void __exit dax_pmem_exit(void)
96 {
97 	driver_unregister(&dax_pmem_driver.drv);
98 }
99 module_exit(dax_pmem_exit);
100 
101 MODULE_LICENSE("GPL v2");
102 MODULE_AUTHOR("Intel Corporation");
103 MODULE_ALIAS_ND_DEVICE(ND_DEVICE_DAX_PMEM);
104