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 "device-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        wait_for_completion(&dax_pmem->cmp);
  47        percpu_ref_exit(ref);
  48}
  49
  50static void dax_pmem_percpu_kill(void *data)
  51{
  52        struct percpu_ref *ref = data;
  53        struct dax_pmem *dax_pmem = to_dax_pmem(ref);
  54
  55        dev_dbg(dax_pmem->dev, "%s\n", __func__);
  56        percpu_ref_kill(ref);
  57}
  58
  59static int dax_pmem_probe(struct device *dev)
  60{
  61        int rc;
  62        void *addr;
  63        struct resource res;
  64        struct nd_pfn_sb *pfn_sb;
  65        struct dev_dax *dev_dax;
  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        dev_dax = devm_create_dev_dax(dax_region, &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
 141static 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
 149static int __init dax_pmem_init(void)
 150{
 151        return nd_driver_register(&dax_pmem_driver);
 152}
 153module_init(dax_pmem_init);
 154
 155static void __exit dax_pmem_exit(void)
 156{
 157        driver_unregister(&dax_pmem_driver.drv);
 158}
 159module_exit(dax_pmem_exit);
 160
 161MODULE_LICENSE("GPL v2");
 162MODULE_AUTHOR("Intel Corporation");
 163MODULE_ALIAS_ND_DEVICE(ND_DEVICE_DAX_PMEM);
 164