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, "trace\n");
  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, "trace\n");
  47         wait_for_completion(&dax_pmem->cmp);
  48         percpu_ref_exit(ref);
  49 }
  50
  51 static void dax_pmem_percpu_kill(struct percpu_ref *ref)
  52 {
  53         struct dax_pmem *dax_pmem = to_dax_pmem(ref);
  54
  55         dev_dbg(dax_pmem->dev, "trace\n");
  56         percpu_ref_kill(ref);
  57 }
  58
  59 static int dax_pmem_probe(struct device *dev)
  60 {
  61         void *addr;
  62         struct resource res;
  63         int rc, id, region_id;
  64         struct nd_pfn_sb *pfn_sb;
  65         struct dev_dax *dev_dax;
  66         struct dax_pmem *dax_pmem;
  67         struct nd_namespace_io *nsio;
  68         struct dax_region *dax_region;
  69         struct nd_namespace_common *ndns;
  70         struct nd_dax *nd_dax = to_nd_dax(dev);
  71         struct nd_pfn *nd_pfn = &nd_dax->nd_pfn;
  72
  73         ndns = nvdimm_namespace_common_probe(dev);
  74         if (IS_ERR(ndns))
  75                 return PTR_ERR(ndns);
  76         nsio = to_nd_namespace_io(&ndns->dev);
  77
  78         dax_pmem = devm_kzalloc(dev, sizeof(*dax_pmem), GFP_KERNEL);
  79         if (!dax_pmem)
  80                 return -ENOMEM;
  81
  82         /* parse the 'pfn' info block via ->rw_bytes */
  83         rc = devm_nsio_enable(dev, nsio);
  84         if (rc)
  85                 return rc;
  86         rc = nvdimm_setup_pfn(nd_pfn, &dax_pmem->pgmap);
  87         if (rc)
  88                 return rc;
  89         devm_nsio_disable(dev, nsio);
  90
  91         pfn_sb = nd_pfn->pfn_sb;
  92
  93         if (!devm_request_mem_region(dev, nsio->res.start,
  94                                 resource_size(&nsio->res),
  95                                 dev_name(&ndns->dev))) {
  96                 dev_warn(dev, "could not reserve region %pR\n", &nsio->res);
  97                 return -EBUSY;
  98         }
  99
 100         dax_pmem->dev = dev;
 101         init_completion(&dax_pmem->cmp);
 102         rc = percpu_ref_init(&dax_pmem->ref, dax_pmem_percpu_release, 0,
 103                         GFP_KERNEL);
 104         if (rc)
 105                 return rc;
 106
 107         rc = devm_add_action(dev, dax_pmem_percpu_exit, &dax_pmem->ref);
 108         if (rc) {
 109                 percpu_ref_exit(&dax_pmem->ref);
 110                 return rc;
 111         }
 112
 113         dax_pmem->pgmap.ref = &dax_pmem->ref;
 114         dax_pmem->pgmap.kill = dax_pmem_percpu_kill;
 115         addr = devm_memremap_pages(dev, &dax_pmem->pgmap);
 116         if (IS_ERR(addr))
 117                 return PTR_ERR(addr);
 118
 119         /* adjust the dax_region resource to the start of data */
 120         memcpy(&res, &dax_pmem->pgmap.res, sizeof(res));
 121         res.start += le64_to_cpu(pfn_sb->dataoff);
 122
 123         rc = sscanf(dev_name(&ndns->dev), "namespace%d.%d", &region_id, &id);
 124         if (rc != 2)
 125                 return -EINVAL;
 126
 127         dax_region = alloc_dax_region(dev, 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         dev_dax = devm_create_dev_dax(dax_region, id, &res, 1);
 134
 135         /* child dev_dax instances now own the lifetime of the dax_region */
 136         dax_region_put(dax_region);
 137
 138         return PTR_ERR_OR_ZERO(dev_dax);
 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 module_nd_driver(dax_pmem_driver);
 150
 151 MODULE_LICENSE("GPL v2");
 152 MODULE_AUTHOR("Intel Corporation");
 153 MODULE_ALIAS_ND_DEVICE(ND_DEVICE_DAX_PMEM);