drivers/dax/pmem.c

   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
  21 struct dax_pmem {
  22         struct device *dev;
  23         struct percpu_ref ref;
  24         struct dev_pagemap pgmap;
  25         struct completion cmp;
  26 };
  27
  28 static struct dax_pmem *to_dax_pmem(struct percpu_ref *ref)
  29 {
  30         return container_of(ref, struct dax_pmem, ref);
  31 }
  32
  33 static 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, "%s\n", __func__);
  38         complete(&dax_pmem->cmp);
  39 }
  40
  41 static 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, "%s\n", __func__);
  47         wait_for_completion(&dax_pmem->cmp);
  48         percpu_ref_exit(ref);
  49 }
  50
  51 static 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, "%s\n", __func__);
  57         percpu_ref_kill(ref);
  58 }
  59
  60 static 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
 145 static 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
 153 static int __init dax_pmem_init(void)
 154 {
 155         return nd_driver_register(&dax_pmem_driver);
 156 }
 157 module_init(dax_pmem_init);
 158
 159 static void __exit dax_pmem_exit(void)
 160 {
 161         driver_unregister(&dax_pmem_driver.drv);
 162 }
 163 module_exit(dax_pmem_exit);
 164
 165 MODULE_LICENSE("GPL v2");
 166 MODULE_AUTHOR("Intel Corporation");
 167 MODULE_ALIAS_ND_DEVICE(ND_DEVICE_DAX_PMEM);