LXR linux/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
  21struct dax_pmem {
  22        struct device *dev;
  23        struct percpu_ref ref;
  24        struct completion cmp;
  25};
  26
  27static struct dax_pmem *to_dax_pmem(struct percpu_ref *ref)
  28{
  29        return container_of(ref, struct dax_pmem, ref);
  30}
  31
  32static 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
  40static 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
  49static 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
  59static 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), dev_name(dev))) {
  93                dev_warn(dev, "could not reserve region %pR\n", &nsio->res);
  94                return -EBUSY;
  95        }
  96
  97        dax_pmem = devm_kzalloc(dev, sizeof(*dax_pmem), GFP_KERNEL);
  98        if (!dax_pmem)
  99                return -ENOMEM;
 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        addr = devm_memremap_pages(dev, &res, &dax_pmem->ref, altmap);
 114        if (IS_ERR(addr))
 115                return PTR_ERR(addr);
 116
 117        rc = devm_add_action_or_reset(dev, dax_pmem_percpu_kill,
 118                                                        &dax_pmem->ref);
 119        if (rc)
 120                return rc;
 121
 122        /* adjust the dax_region resource to the start of data */
 123        res.start += le64_to_cpu(pfn_sb->dataoff);
 124
 125        nd_region = to_nd_region(dev->parent);
 126        dax_region = alloc_dax_region(dev, nd_region->id, &res,
 127                        le32_to_cpu(pfn_sb->align), addr, PFN_DEV|PFN_MAP);
 128        if (!dax_region)
 129                return -ENOMEM;
 130
 131        /* TODO: support for subdividing a dax region... */
 132        dax_dev = devm_create_dax_dev(dax_region, &res, 1);
 133
 134        /* child dax_dev instances now own the lifetime of the dax_region */
 135        dax_region_put(dax_region);
 136
 137        return PTR_ERR_OR_ZERO(dax_dev);
 138}
 139
 140static struct nd_device_driver dax_pmem_driver = {
 141        .probe = dax_pmem_probe,
 142        .drv = {
 143                .name = "dax_pmem",
 144        },
 145        .type = ND_DRIVER_DAX_PMEM,
 146};
 147
 148static int __init dax_pmem_init(void)
 149{
 150        return nd_driver_register(&dax_pmem_driver);
 151}
 152module_init(dax_pmem_init);
 153
 154static void __exit dax_pmem_exit(void)
 155{
 156        driver_unregister(&dax_pmem_driver.drv);
 157}
 158module_exit(dax_pmem_exit);
 159
 160MODULE_LICENSE("GPL v2");
 161MODULE_AUTHOR("Intel Corporation");
 162MODULE_ALIAS_ND_DEVICE(ND_DEVICE_DAX_PMEM);
 163