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 "dax.h"
  20
  21 struct dax_pmem {
  22         struct device *dev;
  23         struct percpu_ref ref;
  24         struct completion cmp;
  25 };
  26
  27 static struct dax_pmem *to_dax_pmem(struct percpu_ref *ref)
  28 {
  29         return container_of(ref, struct dax_pmem, ref);
  30 }
  31
  32 static void dax_pmem_percpu_release(struct percpu_ref *ref)
  33 {
  34         struct dax_pmem *dax_pmem = to_dax_pmem(ref);
  35
  36         dev_dbg(dax_pmem->dev, "%s\n", __func__);
  37         complete(&dax_pmem->cmp);
  38 }
  39
  40 static void dax_pmem_percpu_exit(void *data)
  41 {
  42         struct percpu_ref *ref = data;
  43         struct dax_pmem *dax_pmem = to_dax_pmem(ref);
  44
  45         dev_dbg(dax_pmem->dev, "%s\n", __func__);
  46         percpu_ref_exit(ref);
  47 }
  48
  49 static void dax_pmem_percpu_kill(void *data)
  50 {
  51         struct percpu_ref *ref = data;
  52         struct dax_pmem *dax_pmem = to_dax_pmem(ref);
  53
  54         dev_dbg(dax_pmem->dev, "%s\n", __func__);
  55         percpu_ref_kill(ref);
  56         wait_for_completion(&dax_pmem->cmp);
  57 }
  58
  59 static int dax_pmem_probe(struct device *dev)
  60 {
  61         int rc;
  62         void *addr;
  63         struct resource res;
  64         struct dax_dev *dax_dev;
  65         struct nd_pfn_sb *pfn_sb;
  66         struct dax_pmem *dax_pmem;
  67         struct nd_region *nd_region;
  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         struct vmem_altmap __altmap, *altmap = NULL;
  74
  75         ndns = nvdimm_namespace_common_probe(dev);
  76         if (IS_ERR(ndns))
  77                 return PTR_ERR(ndns);
  78         nsio = to_nd_namespace_io(&ndns->dev);
  79
  80         /* parse the 'pfn' info block via ->rw_bytes */
  81         rc = devm_nsio_enable(dev, nsio);
  82         if (rc)
  83                 return rc;
  84         altmap = nvdimm_setup_pfn(nd_pfn, &res, &__altmap);
  85         if (IS_ERR(altmap))
  86                 return PTR_ERR(altmap);
  87         devm_nsio_disable(dev, nsio);
  88
  89         pfn_sb = nd_pfn->pfn_sb;
  90
  91         if (!devm_request_mem_region(dev, nsio->res.start,
  92                                 resource_size(&nsio->res),
  93                                 dev_name(&ndns->dev))) {
  94                 dev_warn(dev, "could not reserve region %pR\n", &nsio->res);
  95                 return -EBUSY;
  96         }
  97
  98         dax_pmem = devm_kzalloc(dev, sizeof(*dax_pmem), GFP_KERNEL);
  99         if (!dax_pmem)
 100                 return -ENOMEM;
 101
 102         dax_pmem->dev = dev;
 103         init_completion(&dax_pmem->cmp);
 104         rc = percpu_ref_init(&dax_pmem->ref, dax_pmem_percpu_release, 0,
 105                         GFP_KERNEL);
 106         if (rc)
 107                 return rc;
 108
 109         rc = devm_add_action_or_reset(dev, dax_pmem_percpu_exit,
 110                                                         &dax_pmem->ref);
 111         if (rc)
 112                 return rc;
 113
 114         addr = devm_memremap_pages(dev, &res, &dax_pmem->ref, altmap);
 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         res.start += le64_to_cpu(pfn_sb->dataoff);
 125
 126         nd_region = to_nd_region(dev->parent);
 127         dax_region = alloc_dax_region(dev, nd_region->id, &res,
 128                         le32_to_cpu(pfn_sb->align), addr, PFN_DEV|PFN_MAP);
 129         if (!dax_region)
 130                 return -ENOMEM;
 131
 132         /* TODO: support for subdividing a dax region... */
 133         dax_dev = devm_create_dax_dev(dax_region, &res, 1);
 134
 135         /* child dax_dev instances now own the lifetime of the dax_region */
 136         dax_region_put(dax_region);
 137
 138         return PTR_ERR_OR_ZERO(dax_dev);
 139 }
 140
 141 static struct nd_device_driver dax_pmem_driver = {
 142         .probe = dax_pmem_probe,
 143         .drv = {
 144                 .name = "dax_pmem",
 145         },
 146         .type = ND_DRIVER_DAX_PMEM,
 147 };
 148
 149 static int __init dax_pmem_init(void)
 150 {
 151         return nd_driver_register(&dax_pmem_driver);
 152 }
 153 module_init(dax_pmem_init);
 154
 155 static void __exit dax_pmem_exit(void)
 156 {
 157         driver_unregister(&dax_pmem_driver.drv);
 158 }
 159 module_exit(dax_pmem_exit);
 160
 161 MODULE_LICENSE("GPL v2");
 162 MODULE_AUTHOR("Intel Corporation");
 163 MODULE_ALIAS_ND_DEVICE(ND_DEVICE_DAX_PMEM);