1/*
  2 * Copyright(c) 2016 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/percpu-refcount.h>
 14#include <linux/memremap.h>
 15#include <linux/module.h>
 16#include <linux/pfn_t.h>
 17#include "../nvdimm/pfn.h"
 18#include "../nvdimm/nd.h"
 19#include "device-dax.h"
 20
 21struct dax_pmem {
 22	struct device *dev;
 23	struct percpu_ref ref;
 24	struct dev_pagemap pgmap;
 25	struct completion cmp;
 26};
 27
 28static struct dax_pmem *to_dax_pmem(struct percpu_ref *ref)
 29{
 30	return container_of(ref, struct dax_pmem, ref);
 31}
 32
 33static void dax_pmem_percpu_release(struct percpu_ref *ref)
 34{
 35	struct dax_pmem *dax_pmem = to_dax_pmem(ref);
 36
 37	dev_dbg(dax_pmem->dev, "trace\n");
 38	complete(&dax_pmem->cmp);
 39}
 40
 41static void dax_pmem_percpu_exit(void *data)
 42{
 43	struct percpu_ref *ref = data;
 44	struct dax_pmem *dax_pmem = to_dax_pmem(ref);
 45
 46	dev_dbg(dax_pmem->dev, "trace\n");
 47	wait_for_completion(&dax_pmem->cmp);
 48	percpu_ref_exit(ref);
 49}
 50
 51static void dax_pmem_percpu_kill(void *data)
 52{
 53	struct percpu_ref *ref = data;
 54	struct dax_pmem *dax_pmem = to_dax_pmem(ref);
 55
 56	dev_dbg(dax_pmem->dev, "trace\n");
 57	percpu_ref_kill(ref);
 58}
 59
 60static int dax_pmem_probe(struct device *dev)
 61{
 62	void *addr;
 63	struct resource res;
 64	int rc, id, region_id;
 65	struct nd_pfn_sb *pfn_sb;
 66	struct dev_dax *dev_dax;
 67	struct dax_pmem *dax_pmem;
 68	struct nd_namespace_io *nsio;
 69	struct dax_region *dax_region;
 70	struct nd_namespace_common *ndns;
 71	struct nd_dax *nd_dax = to_nd_dax(dev);
 72	struct nd_pfn *nd_pfn = &nd_dax->nd_pfn;
 73
 74	ndns = nvdimm_namespace_common_probe(dev);
 75	if (IS_ERR(ndns))
 76		return PTR_ERR(ndns);
 77	nsio = to_nd_namespace_io(&ndns->dev);
 78
 79	dax_pmem = devm_kzalloc(dev, sizeof(*dax_pmem), GFP_KERNEL);
 80	if (!dax_pmem)
 81		return -ENOMEM;
 82
 83	/* parse the 'pfn' info block via ->rw_bytes */
 84	rc = devm_nsio_enable(dev, nsio);
 85	if (rc)
 86		return rc;
 87	rc = nvdimm_setup_pfn(nd_pfn, &dax_pmem->pgmap);
 88	if (rc)
 89		return rc;
 90	devm_nsio_disable(dev, nsio);
 91
 92	pfn_sb = nd_pfn->pfn_sb;
 93
 94	if (!devm_request_mem_region(dev, nsio->res.start,
 95				resource_size(&nsio->res),
 96				dev_name(&ndns->dev))) {
 97		dev_warn(dev, "could not reserve region %pR\n", &nsio->res);
 98		return -EBUSY;
 99	}
100
101	dax_pmem->dev = dev;
102	init_completion(&dax_pmem->cmp);
103	rc = percpu_ref_init(&dax_pmem->ref, dax_pmem_percpu_release, 0,
104			GFP_KERNEL);
105	if (rc)
106		return rc;
107
108	rc = devm_add_action_or_reset(dev, dax_pmem_percpu_exit,
109							&dax_pmem->ref);
110	if (rc)
111		return rc;
112
113	dax_pmem->pgmap.ref = &dax_pmem->ref;
114	addr = devm_memremap_pages(dev, &dax_pmem->pgmap);
115	if (IS_ERR(addr))
116		return PTR_ERR(addr);
117
118	rc = devm_add_action_or_reset(dev, dax_pmem_percpu_kill,
119							&dax_pmem->ref);
120	if (rc)
121		return rc;
122
123	/* adjust the dax_region resource to the start of data */
124	memcpy(&res, &dax_pmem->pgmap.res, sizeof(res));
125	res.start += le64_to_cpu(pfn_sb->dataoff);
126
127	rc = sscanf(dev_name(&ndns->dev), "namespace%d.%d", &region_id, &id);
128	if (rc != 2)
129		return -EINVAL;
130
131	dax_region = alloc_dax_region(dev, region_id, &res,
132			le32_to_cpu(pfn_sb->align), addr, PFN_DEV|PFN_MAP);
133	if (!dax_region)
134		return -ENOMEM;
135
136	/* TODO: support for subdividing a dax region... */
137	dev_dax = devm_create_dev_dax(dax_region, id, &res, 1);
138
139	/* child dev_dax instances now own the lifetime of the dax_region */
140	dax_region_put(dax_region);
141
142	return PTR_ERR_OR_ZERO(dev_dax);
143}
144
145static struct nd_device_driver dax_pmem_driver = {
146	.probe = dax_pmem_probe,
147	.drv = {
148		.name = "dax_pmem",
149	},
150	.type = ND_DRIVER_DAX_PMEM,
151};
152
153module_nd_driver(dax_pmem_driver);
154
155MODULE_LICENSE("GPL v2");
156MODULE_AUTHOR("Intel Corporation");
157MODULE_ALIAS_ND_DEVICE(ND_DEVICE_DAX_PMEM);