drivers/dax/pmem.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 /* Copyright(c) 2016 - 2018 Intel Corporation. All rights reserved. */
0003 #include <linux/memremap.h>
0004 #include <linux/module.h>
0005 #include <linux/pfn_t.h>
0006 #include "../nvdimm/pfn.h"
0007 #include "../nvdimm/nd.h"
0008 #include "bus.h"
0009
0010 static struct dev_dax *__dax_pmem_probe(struct device *dev)
0011 {
0012     struct range range;
0013     int rc, id, region_id;
0014     resource_size_t offset;
0015     struct nd_pfn_sb *pfn_sb;
0016     struct dev_dax *dev_dax;
0017     struct dev_dax_data data;
0018     struct nd_namespace_io *nsio;
0019     struct dax_region *dax_region;
0020     struct dev_pagemap pgmap = { };
0021     struct nd_namespace_common *ndns;
0022     struct nd_dax *nd_dax = to_nd_dax(dev);
0023     struct nd_pfn *nd_pfn = &nd_dax->nd_pfn;
0024     struct nd_region *nd_region = to_nd_region(dev->parent);
0025
0026     ndns = nvdimm_namespace_common_probe(dev);
0027     if (IS_ERR(ndns))
0028         return ERR_CAST(ndns);
0029
0030     /* parse the 'pfn' info block via ->rw_bytes */
0031     rc = devm_namespace_enable(dev, ndns, nd_info_block_reserve());
0032     if (rc)
0033         return ERR_PTR(rc);
0034     rc = nvdimm_setup_pfn(nd_pfn, &pgmap);
0035     if (rc)
0036         return ERR_PTR(rc);
0037     devm_namespace_disable(dev, ndns);
0038
0039     /* reserve the metadata area, device-dax will reserve the data */
0040     pfn_sb = nd_pfn->pfn_sb;
0041     offset = le64_to_cpu(pfn_sb->dataoff);
0042     nsio = to_nd_namespace_io(&ndns->dev);
0043     if (!devm_request_mem_region(dev, nsio->res.start, offset,
0044                 dev_name(&ndns->dev))) {
0045         dev_warn(dev, "could not reserve metadata\n");
0046         return ERR_PTR(-EBUSY);
0047     }
0048
0049     rc = sscanf(dev_name(&ndns->dev), "namespace%d.%d", &region_id, &id);
0050     if (rc != 2)
0051         return ERR_PTR(-EINVAL);
0052
0053     /* adjust the dax_region range to the start of data */
0054     range = pgmap.range;
0055     range.start += offset;
0056     dax_region = alloc_dax_region(dev, region_id, &range,
0057             nd_region->target_node, le32_to_cpu(pfn_sb->align),
0058             IORESOURCE_DAX_STATIC);
0059     if (!dax_region)
0060         return ERR_PTR(-ENOMEM);
0061
0062     data = (struct dev_dax_data) {
0063         .dax_region = dax_region,
0064         .id = id,
0065         .pgmap = &pgmap,
0066         .size = range_len(&range),
0067     };
0068     dev_dax = devm_create_dev_dax(&data);
0069
0070     /* child dev_dax instances now own the lifetime of the dax_region */
0071     dax_region_put(dax_region);
0072
0073     return dev_dax;
0074 }
0075
0076 static int dax_pmem_probe(struct device *dev)
0077 {
0078     return PTR_ERR_OR_ZERO(__dax_pmem_probe(dev));
0079 }
0080
0081 static struct nd_device_driver dax_pmem_driver = {
0082     .probe = dax_pmem_probe,
0083     .drv = {
0084         .name = "dax_pmem",
0085     },
0086     .type = ND_DRIVER_DAX_PMEM,
0087 };
0088
0089 static int __init dax_pmem_init(void)
0090 {
0091     return nd_driver_register(&dax_pmem_driver);
0092 }
0093 module_init(dax_pmem_init);
0094
0095 static void __exit dax_pmem_exit(void)
0096 {
0097     driver_unregister(&dax_pmem_driver.drv);
0098 }
0099 module_exit(dax_pmem_exit);
0100
0101 MODULE_LICENSE("GPL v2");
0102 MODULE_AUTHOR("Intel Corporation");
0103 MODULE_ALIAS_ND_DEVICE(ND_DEVICE_DAX_PMEM);