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