drivers/nvdimm/pmem.c

   1 /*
   2  * Persistent Memory Driver
   3  *
   4  * Copyright (c) 2014-2015, Intel Corporation.
   5  * Copyright (c) 2015, Christoph Hellwig <hch@lst.de>.
   6  * Copyright (c) 2015, Boaz Harrosh <boaz@plexistor.com>.
   7  *
   8  * This program is free software; you can redistribute it and/or modify it
   9  * under the terms and conditions of the GNU General Public License,
  10  * version 2, as published by the Free Software Foundation.
  11  *
  12  * This program is distributed in the hope it will be useful, but WITHOUT
  13  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  15  * more details.
  16  */
  17
  18 #include <asm/cacheflush.h>
  19 #include <linux/blkdev.h>
  20 #include <linux/hdreg.h>
  21 #include <linux/init.h>
  22 #include <linux/platform_device.h>
  23 #include <linux/module.h>
  24 #include <linux/moduleparam.h>
  25 #include <linux/slab.h>
  26 #include <linux/pmem.h>
  27 #include <linux/nd.h>
  28 #include "nd.h"
  29
  30 struct pmem_device {
  31         struct request_queue    *pmem_queue;
  32         struct gendisk          *pmem_disk;
  33
  34         /* One contiguous memory region per device */
  35         phys_addr_t             phys_addr;
  36         void __pmem             *virt_addr;
  37         size_t                  size;
  38 };
  39
  40 static int pmem_major;
  41
  42 static void pmem_do_bvec(struct pmem_device *pmem, struct page *page,
  43                         unsigned int len, unsigned int off, int rw,
  44                         sector_t sector)
  45 {
  46         void *mem = kmap_atomic(page);
  47         size_t pmem_off = sector << 9;
  48         void __pmem *pmem_addr = pmem->virt_addr + pmem_off;
  49
  50         if (rw == READ) {
  51                 memcpy_from_pmem(mem + off, pmem_addr, len);
  52                 flush_dcache_page(page);
  53         } else {
  54                 flush_dcache_page(page);
  55                 memcpy_to_pmem(pmem_addr, mem + off, len);
  56         }
  57
  58         kunmap_atomic(mem);
  59 }
  60
  61 static void pmem_make_request(struct request_queue *q, struct bio *bio)
  62 {
  63         bool do_acct;
  64         unsigned long start;
  65         struct bio_vec bvec;
  66         struct bvec_iter iter;
  67         struct block_device *bdev = bio->bi_bdev;
  68         struct pmem_device *pmem = bdev->bd_disk->private_data;
  69
  70         do_acct = nd_iostat_start(bio, &start);
  71         bio_for_each_segment(bvec, bio, iter)
  72                 pmem_do_bvec(pmem, bvec.bv_page, bvec.bv_len, bvec.bv_offset,
  73                                 bio_data_dir(bio), iter.bi_sector);
  74         if (do_acct)
  75                 nd_iostat_end(bio, start);
  76
  77         if (bio_data_dir(bio))
  78                 wmb_pmem();
  79
  80         bio_endio(bio, 0);
  81 }
  82
  83 static int pmem_rw_page(struct block_device *bdev, sector_t sector,
  84                        struct page *page, int rw)
  85 {
  86         struct pmem_device *pmem = bdev->bd_disk->private_data;
  87
  88         pmem_do_bvec(pmem, page, PAGE_CACHE_SIZE, 0, rw, sector);
  89         page_endio(page, rw & WRITE, 0);
  90
  91         return 0;
  92 }
  93
  94 static long pmem_direct_access(struct block_device *bdev, sector_t sector,
  95                               void **kaddr, unsigned long *pfn, long size)
  96 {
  97         struct pmem_device *pmem = bdev->bd_disk->private_data;
  98         size_t offset = sector << 9;
  99
 100         if (!pmem)
 101                 return -ENODEV;
 102
 103         /* FIXME convert DAX to comprehend that this mapping has a lifetime */
 104         *kaddr = (void __force *) pmem->virt_addr + offset;
 105         *pfn = (pmem->phys_addr + offset) >> PAGE_SHIFT;
 106
 107         return pmem->size - offset;
 108 }
 109
 110 static const struct block_device_operations pmem_fops = {
 111         .owner =                THIS_MODULE,
 112         .rw_page =              pmem_rw_page,
 113         .direct_access =        pmem_direct_access,
 114         .revalidate_disk =      nvdimm_revalidate_disk,
 115 };
 116
 117 static struct pmem_device *pmem_alloc(struct device *dev,
 118                 struct resource *res, int id)
 119 {
 120         struct pmem_device *pmem;
 121
 122         pmem = kzalloc(sizeof(*pmem), GFP_KERNEL);
 123         if (!pmem)
 124                 return ERR_PTR(-ENOMEM);
 125
 126         pmem->phys_addr = res->start;
 127         pmem->size = resource_size(res);
 128         if (!arch_has_pmem_api())
 129                 dev_warn(dev, "unable to guarantee persistence of writes\n");
 130
 131         if (!request_mem_region(pmem->phys_addr, pmem->size, dev_name(dev))) {
 132                 dev_warn(dev, "could not reserve region [0x%pa:0x%zx]\n",
 133                                 &pmem->phys_addr, pmem->size);
 134                 kfree(pmem);
 135                 return ERR_PTR(-EBUSY);
 136         }
 137
 138         pmem->virt_addr = memremap_pmem(pmem->phys_addr, pmem->size);
 139         if (!pmem->virt_addr) {
 140                 release_mem_region(pmem->phys_addr, pmem->size);
 141                 kfree(pmem);
 142                 return ERR_PTR(-ENXIO);
 143         }
 144
 145         return pmem;
 146 }
 147
 148 static void pmem_detach_disk(struct pmem_device *pmem)
 149 {
 150         del_gendisk(pmem->pmem_disk);
 151         put_disk(pmem->pmem_disk);
 152         blk_cleanup_queue(pmem->pmem_queue);
 153 }
 154
 155 static int pmem_attach_disk(struct nd_namespace_common *ndns,
 156                 struct pmem_device *pmem)
 157 {
 158         struct gendisk *disk;
 159
 160         pmem->pmem_queue = blk_alloc_queue(GFP_KERNEL);
 161         if (!pmem->pmem_queue)
 162                 return -ENOMEM;
 163
 164         blk_queue_make_request(pmem->pmem_queue, pmem_make_request);
 165         blk_queue_max_hw_sectors(pmem->pmem_queue, UINT_MAX);
 166         blk_queue_bounce_limit(pmem->pmem_queue, BLK_BOUNCE_ANY);
 167         queue_flag_set_unlocked(QUEUE_FLAG_NONROT, pmem->pmem_queue);
 168
 169         disk = alloc_disk(0);
 170         if (!disk) {
 171                 blk_cleanup_queue(pmem->pmem_queue);
 172                 return -ENOMEM;
 173         }
 174
 175         disk->major             = pmem_major;
 176         disk->first_minor       = 0;
 177         disk->fops              = &pmem_fops;
 178         disk->private_data      = pmem;
 179         disk->queue             = pmem->pmem_queue;
 180         disk->flags             = GENHD_FL_EXT_DEVT;
 181         nvdimm_namespace_disk_name(ndns, disk->disk_name);
 182         disk->driverfs_dev = &ndns->dev;
 183         set_capacity(disk, pmem->size >> 9);
 184         pmem->pmem_disk = disk;
 185
 186         add_disk(disk);
 187         revalidate_disk(disk);
 188
 189         return 0;
 190 }
 191
 192 static int pmem_rw_bytes(struct nd_namespace_common *ndns,
 193                 resource_size_t offset, void *buf, size_t size, int rw)
 194 {
 195         struct pmem_device *pmem = dev_get_drvdata(ndns->claim);
 196
 197         if (unlikely(offset + size > pmem->size)) {
 198                 dev_WARN_ONCE(&ndns->dev, 1, "request out of range\n");
 199                 return -EFAULT;
 200         }
 201
 202         if (rw == READ)
 203                 memcpy_from_pmem(buf, pmem->virt_addr + offset, size);
 204         else {
 205                 memcpy_to_pmem(pmem->virt_addr + offset, buf, size);
 206                 wmb_pmem();
 207         }
 208
 209         return 0;
 210 }
 211
 212 static void pmem_free(struct pmem_device *pmem)
 213 {
 214         memunmap_pmem(pmem->virt_addr);
 215         release_mem_region(pmem->phys_addr, pmem->size);
 216         kfree(pmem);
 217 }
 218
 219 static int nd_pmem_probe(struct device *dev)
 220 {
 221         struct nd_region *nd_region = to_nd_region(dev->parent);
 222         struct nd_namespace_common *ndns;
 223         struct nd_namespace_io *nsio;
 224         struct pmem_device *pmem;
 225         int rc;
 226
 227         ndns = nvdimm_namespace_common_probe(dev);
 228         if (IS_ERR(ndns))
 229                 return PTR_ERR(ndns);
 230
 231         nsio = to_nd_namespace_io(&ndns->dev);
 232         pmem = pmem_alloc(dev, &nsio->res, nd_region->id);
 233         if (IS_ERR(pmem))
 234                 return PTR_ERR(pmem);
 235
 236         dev_set_drvdata(dev, pmem);
 237         ndns->rw_bytes = pmem_rw_bytes;
 238         if (is_nd_btt(dev))
 239                 rc = nvdimm_namespace_attach_btt(ndns);
 240         else if (nd_btt_probe(ndns, pmem) == 0) {
 241                 /* we'll come back as btt-pmem */
 242                 rc = -ENXIO;
 243         } else
 244                 rc = pmem_attach_disk(ndns, pmem);
 245         if (rc)
 246                 pmem_free(pmem);
 247         return rc;
 248 }
 249
 250 static int nd_pmem_remove(struct device *dev)
 251 {
 252         struct pmem_device *pmem = dev_get_drvdata(dev);
 253
 254         if (is_nd_btt(dev))
 255                 nvdimm_namespace_detach_btt(to_nd_btt(dev)->ndns);
 256         else
 257                 pmem_detach_disk(pmem);
 258         pmem_free(pmem);
 259
 260         return 0;
 261 }
 262
 263 MODULE_ALIAS("pmem");
 264 MODULE_ALIAS_ND_DEVICE(ND_DEVICE_NAMESPACE_IO);
 265 MODULE_ALIAS_ND_DEVICE(ND_DEVICE_NAMESPACE_PMEM);
 266 static struct nd_device_driver nd_pmem_driver = {
 267         .probe = nd_pmem_probe,
 268         .remove = nd_pmem_remove,
 269         .drv = {
 270                 .name = "nd_pmem",
 271         },
 272         .type = ND_DRIVER_NAMESPACE_IO | ND_DRIVER_NAMESPACE_PMEM,
 273 };
 274
 275 static int __init pmem_init(void)
 276 {
 277         int error;
 278
 279         pmem_major = register_blkdev(0, "pmem");
 280         if (pmem_major < 0)
 281                 return pmem_major;
 282
 283         error = nd_driver_register(&nd_pmem_driver);
 284         if (error) {
 285                 unregister_blkdev(pmem_major, "pmem");
 286                 return error;
 287         }
 288
 289         return 0;
 290 }
 291 module_init(pmem_init);
 292
 293 static void pmem_exit(void)
 294 {
 295         driver_unregister(&nd_pmem_driver.drv);
 296         unregister_blkdev(pmem_major, "pmem");
 297 }
 298 module_exit(pmem_exit);
 299
 300 MODULE_AUTHOR("Ross Zwisler <ross.zwisler@linux.intel.com>");
 301 MODULE_LICENSE("GPL v2");