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/nd.h>
  27 #include "nd.h"
  28
  29 struct pmem_device {
  30         struct request_queue    *pmem_queue;
  31         struct gendisk          *pmem_disk;
  32
  33         /* One contiguous memory region per device */
  34         phys_addr_t             phys_addr;
  35         void                    *virt_addr;
  36         size_t                  size;
  37 };
  38
  39 static int pmem_major;
  40
  41 static void pmem_do_bvec(struct pmem_device *pmem, struct page *page,
  42                         unsigned int len, unsigned int off, int rw,
  43                         sector_t sector)
  44 {
  45         void *mem = kmap_atomic(page);
  46         size_t pmem_off = sector << 9;
  47
  48         if (rw == READ) {
  49                 memcpy(mem + off, pmem->virt_addr + pmem_off, len);
  50                 flush_dcache_page(page);
  51         } else {
  52                 flush_dcache_page(page);
  53                 memcpy(pmem->virt_addr + pmem_off, mem + off, len);
  54         }
  55
  56         kunmap_atomic(mem);
  57 }
  58
  59 static void pmem_make_request(struct request_queue *q, struct bio *bio)
  60 {
  61         struct block_device *bdev = bio->bi_bdev;
  62         struct pmem_device *pmem = bdev->bd_disk->private_data;
  63         int rw;
  64         struct bio_vec bvec;
  65         sector_t sector;
  66         struct bvec_iter iter;
  67         int err = 0;
  68
  69         if (bio_end_sector(bio) > get_capacity(bdev->bd_disk)) {
  70                 err = -EIO;
  71                 goto out;
  72         }
  73
  74         BUG_ON(bio->bi_rw & REQ_DISCARD);
  75
  76         rw = bio_data_dir(bio);
  77         sector = bio->bi_iter.bi_sector;
  78         bio_for_each_segment(bvec, bio, iter) {
  79                 pmem_do_bvec(pmem, bvec.bv_page, bvec.bv_len, bvec.bv_offset,
  80                              rw, sector);
  81                 sector += bvec.bv_len >> 9;
  82         }
  83
  84 out:
  85         bio_endio(bio, err);
  86 }
  87
  88 static int pmem_rw_page(struct block_device *bdev, sector_t sector,
  89                        struct page *page, int rw)
  90 {
  91         struct pmem_device *pmem = bdev->bd_disk->private_data;
  92
  93         pmem_do_bvec(pmem, page, PAGE_CACHE_SIZE, 0, rw, sector);
  94         page_endio(page, rw & WRITE, 0);
  95
  96         return 0;
  97 }
  98
  99 static long pmem_direct_access(struct block_device *bdev, sector_t sector,
 100                               void **kaddr, unsigned long *pfn, long size)
 101 {
 102         struct pmem_device *pmem = bdev->bd_disk->private_data;
 103         size_t offset = sector << 9;
 104
 105         if (!pmem)
 106                 return -ENODEV;
 107
 108         *kaddr = pmem->virt_addr + offset;
 109         *pfn = (pmem->phys_addr + offset) >> PAGE_SHIFT;
 110
 111         return pmem->size - offset;
 112 }
 113
 114 static const struct block_device_operations pmem_fops = {
 115         .owner =                THIS_MODULE,
 116         .rw_page =              pmem_rw_page,
 117         .direct_access =        pmem_direct_access,
 118 };
 119
 120 static struct pmem_device *pmem_alloc(struct device *dev,
 121                 struct resource *res, int id)
 122 {
 123         struct pmem_device *pmem;
 124         struct gendisk *disk;
 125         int err;
 126
 127         err = -ENOMEM;
 128         pmem = kzalloc(sizeof(*pmem), GFP_KERNEL);
 129         if (!pmem)
 130                 goto out;
 131
 132         pmem->phys_addr = res->start;
 133         pmem->size = resource_size(res);
 134
 135         err = -EINVAL;
 136         if (!request_mem_region(pmem->phys_addr, pmem->size, "pmem")) {
 137                 dev_warn(dev, "could not reserve region [0x%pa:0x%zx]\n",
 138                                 &pmem->phys_addr, pmem->size);
 139                 goto out_free_dev;
 140         }
 141
 142         /*
 143          * Map the memory as non-cachable, as we can't write back the contents
 144          * of the CPU caches in case of a crash.
 145          */
 146         err = -ENOMEM;
 147         pmem->virt_addr = ioremap_nocache(pmem->phys_addr, pmem->size);
 148         if (!pmem->virt_addr)
 149                 goto out_release_region;
 150
 151         pmem->pmem_queue = blk_alloc_queue(GFP_KERNEL);
 152         if (!pmem->pmem_queue)
 153                 goto out_unmap;
 154
 155         blk_queue_make_request(pmem->pmem_queue, pmem_make_request);
 156         blk_queue_max_hw_sectors(pmem->pmem_queue, 1024);
 157         blk_queue_bounce_limit(pmem->pmem_queue, BLK_BOUNCE_ANY);
 158
 159         disk = alloc_disk(0);
 160         if (!disk)
 161                 goto out_free_queue;
 162
 163         disk->major             = pmem_major;
 164         disk->first_minor       = 0;
 165         disk->fops              = &pmem_fops;
 166         disk->private_data      = pmem;
 167         disk->queue             = pmem->pmem_queue;
 168         disk->flags             = GENHD_FL_EXT_DEVT;
 169         sprintf(disk->disk_name, "pmem%d", id);
 170         disk->driverfs_dev = dev;
 171         set_capacity(disk, pmem->size >> 9);
 172         pmem->pmem_disk = disk;
 173
 174         add_disk(disk);
 175
 176         return pmem;
 177
 178 out_free_queue:
 179         blk_cleanup_queue(pmem->pmem_queue);
 180 out_unmap:
 181         iounmap(pmem->virt_addr);
 182 out_release_region:
 183         release_mem_region(pmem->phys_addr, pmem->size);
 184 out_free_dev:
 185         kfree(pmem);
 186 out:
 187         return ERR_PTR(err);
 188 }
 189
 190 static void pmem_free(struct pmem_device *pmem)
 191 {
 192         del_gendisk(pmem->pmem_disk);
 193         put_disk(pmem->pmem_disk);
 194         blk_cleanup_queue(pmem->pmem_queue);
 195         iounmap(pmem->virt_addr);
 196         release_mem_region(pmem->phys_addr, pmem->size);
 197         kfree(pmem);
 198 }
 199
 200 static int nd_pmem_probe(struct device *dev)
 201 {
 202         struct nd_region *nd_region = to_nd_region(dev->parent);
 203         struct nd_namespace_io *nsio = to_nd_namespace_io(dev);
 204         struct pmem_device *pmem;
 205
 206         if (resource_size(&nsio->res) < ND_MIN_NAMESPACE_SIZE) {
 207                 resource_size_t size = resource_size(&nsio->res);
 208
 209                 dev_dbg(dev, "%s: size: %pa, too small must be at least %#x\n",
 210                                 __func__, &size, ND_MIN_NAMESPACE_SIZE);
 211                 return -ENODEV;
 212         }
 213
 214         if (nd_region_to_nstype(nd_region) == ND_DEVICE_NAMESPACE_PMEM) {
 215                 struct nd_namespace_pmem *nspm = to_nd_namespace_pmem(dev);
 216
 217                 if (!nspm->uuid) {
 218                         dev_dbg(dev, "%s: uuid not set\n", __func__);
 219                         return -ENODEV;
 220                 }
 221         }
 222
 223         pmem = pmem_alloc(dev, &nsio->res, nd_region->id);
 224         if (IS_ERR(pmem))
 225                 return PTR_ERR(pmem);
 226
 227         dev_set_drvdata(dev, pmem);
 228
 229         return 0;
 230 }
 231
 232 static int nd_pmem_remove(struct device *dev)
 233 {
 234         struct pmem_device *pmem = dev_get_drvdata(dev);
 235
 236         pmem_free(pmem);
 237         return 0;
 238 }
 239
 240 MODULE_ALIAS("pmem");
 241 MODULE_ALIAS_ND_DEVICE(ND_DEVICE_NAMESPACE_IO);
 242 MODULE_ALIAS_ND_DEVICE(ND_DEVICE_NAMESPACE_PMEM);
 243 static struct nd_device_driver nd_pmem_driver = {
 244         .probe = nd_pmem_probe,
 245         .remove = nd_pmem_remove,
 246         .drv = {
 247                 .name = "nd_pmem",
 248         },
 249         .type = ND_DRIVER_NAMESPACE_IO | ND_DRIVER_NAMESPACE_PMEM,
 250 };
 251
 252 static int __init pmem_init(void)
 253 {
 254         int error;
 255
 256         pmem_major = register_blkdev(0, "pmem");
 257         if (pmem_major < 0)
 258                 return pmem_major;
 259
 260         error = nd_driver_register(&nd_pmem_driver);
 261         if (error) {
 262                 unregister_blkdev(pmem_major, "pmem");
 263                 return error;
 264         }
 265
 266         return 0;
 267 }
 268 module_init(pmem_init);
 269
 270 static void pmem_exit(void)
 271 {
 272         driver_unregister(&nd_pmem_driver.drv);
 273         unregister_blkdev(pmem_major, "pmem");
 274 }
 275 module_exit(pmem_exit);
 276
 277 MODULE_AUTHOR("Ross Zwisler <ross.zwisler@linux.intel.com>");
 278 MODULE_LICENSE("GPL v2");