1/*
2 * Copyright(c) 2013-2015 Intel Corporation. All rights reserved.
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of version 2 of the GNU General Public License as
6 * published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful, but
9 * WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
11 * General Public License for more details.
12 */
13#include <linux/cpumask.h>
14#include <linux/module.h>
15#include <linux/device.h>
16#include <linux/nd.h>
17#include "nd.h"
18
19static int nd_region_probe(struct device *dev)
20{
21	int err, rc;
22	static unsigned long once;
23	struct nd_region_namespaces *num_ns;
24	struct nd_region *nd_region = to_nd_region(dev);
25
26	if (nd_region->num_lanes > num_online_cpus()
27			&& nd_region->num_lanes < num_possible_cpus()
28			&& !test_and_set_bit(0, &once)) {
29		dev_info(dev, "online cpus (%d) < concurrent i/o lanes (%d) < possible cpus (%d)\n",
30				num_online_cpus(), nd_region->num_lanes,
31				num_possible_cpus());
32		dev_info(dev, "setting nr_cpus=%d may yield better libnvdimm device performance\n",
33				nd_region->num_lanes);
34	}
35
36	rc = nd_blk_region_init(nd_region);
37	if (rc)
38		return rc;
39
40	rc = nd_region_register_namespaces(nd_region, &err);
41	num_ns = devm_kzalloc(dev, sizeof(*num_ns), GFP_KERNEL);
42	if (!num_ns)
43		return -ENOMEM;
44
45	if (rc < 0)
46		return rc;
47
48	num_ns->active = rc;
49	num_ns->count = rc + err;
50	dev_set_drvdata(dev, num_ns);
51
52	if (rc && err && rc == err)
53		return -ENODEV;
54
55	nd_region->btt_seed = nd_btt_create(nd_region);
56	nd_region->pfn_seed = nd_pfn_create(nd_region);
57	if (err == 0)
58		return 0;
59
60	/*
61	 * Given multiple namespaces per region, we do not want to
62	 * disable all the successfully registered peer namespaces upon
63	 * a single registration failure.  If userspace is missing a
64	 * namespace that it expects it can disable/re-enable the region
65	 * to retry discovery after correcting the failure.
66	 * <regionX>/namespaces returns the current
67	 * "<async-registered>/<total>" namespace count.
68	 */
69	dev_err(dev, "failed to register %d namespace%s, continuing...\n",
70			err, err == 1 ? "" : "s");
71	return 0;
72}
73
74static int child_unregister(struct device *dev, void *data)
75{
76	nd_device_unregister(dev, ND_SYNC);
77	return 0;
78}
79
80static int nd_region_remove(struct device *dev)
81{
82	struct nd_region *nd_region = to_nd_region(dev);
83
84	/* flush attribute readers and disable */
85	nvdimm_bus_lock(dev);
86	nd_region->ns_seed = NULL;
87	nd_region->btt_seed = NULL;
88	nd_region->pfn_seed = NULL;
89	dev_set_drvdata(dev, NULL);
90	nvdimm_bus_unlock(dev);
91
92	device_for_each_child(dev, NULL, child_unregister);
93	return 0;
94}
95
96static struct nd_device_driver nd_region_driver = {
97	.probe = nd_region_probe,
98	.remove = nd_region_remove,
99	.drv = {
100		.name = "nd_region",
101	},
102	.type = ND_DRIVER_REGION_BLK | ND_DRIVER_REGION_PMEM,
103};
104
105int __init nd_region_init(void)
106{
107	return nd_driver_register(&nd_region_driver);
108}
109
110void nd_region_exit(void)
111{
112	driver_unregister(&nd_region_driver.drv);
113}
114
115MODULE_ALIAS_ND_DEVICE(ND_DEVICE_REGION_PMEM);
116MODULE_ALIAS_ND_DEVICE(ND_DEVICE_REGION_BLK);
117