pmem.c

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