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