2 * Persistent Memory Driver
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>.
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.
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
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>
31 struct request_queue *pmem_queue;
32 struct gendisk *pmem_disk;
34 /* One contiguous memory region per device */
35 phys_addr_t phys_addr;
36 void __pmem *virt_addr;
40 static int pmem_major;
42 static void pmem_do_bvec(struct pmem_device *pmem, struct page *page,
43 unsigned int len, unsigned int off, int rw,
46 void *mem = kmap_atomic(page);
47 size_t pmem_off = sector << 9;
48 void __pmem *pmem_addr = pmem->virt_addr + pmem_off;
51 memcpy_from_pmem(mem + off, pmem_addr, len);
52 flush_dcache_page(page);
54 flush_dcache_page(page);
55 memcpy_to_pmem(pmem_addr, mem + off, len);
61 static void pmem_make_request(struct request_queue *q, struct bio *bio)
66 struct bvec_iter iter;
67 struct block_device *bdev = bio->bi_bdev;
68 struct pmem_device *pmem = bdev->bd_disk->private_data;
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);
75 nd_iostat_end(bio, start);
77 if (bio_data_dir(bio))
83 static int pmem_rw_page(struct block_device *bdev, sector_t sector,
84 struct page *page, int rw)
86 struct pmem_device *pmem = bdev->bd_disk->private_data;
88 pmem_do_bvec(pmem, page, PAGE_CACHE_SIZE, 0, rw, sector);
89 page_endio(page, rw & WRITE, 0);
94 static long pmem_direct_access(struct block_device *bdev, sector_t sector,
95 void __pmem **kaddr, unsigned long *pfn, long size)
97 struct pmem_device *pmem = bdev->bd_disk->private_data;
98 size_t offset = sector << 9;
103 /* FIXME convert DAX to comprehend that this mapping has a lifetime */
104 *kaddr = pmem->virt_addr + offset;
105 *pfn = (pmem->phys_addr + offset) >> PAGE_SHIFT;
107 return pmem->size - offset;
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,
117 static struct pmem_device *pmem_alloc(struct device *dev,
118 struct resource *res, int id)
120 struct pmem_device *pmem;
122 pmem = devm_kzalloc(dev, sizeof(*pmem), GFP_KERNEL);
124 return ERR_PTR(-ENOMEM);
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");
131 if (!devm_request_mem_region(dev, pmem->phys_addr, pmem->size,
133 dev_warn(dev, "could not reserve region [0x%pa:0x%zx]\n",
134 &pmem->phys_addr, pmem->size);
135 return ERR_PTR(-EBUSY);
138 pmem->virt_addr = memremap_pmem(dev, pmem->phys_addr, pmem->size);
139 if (!pmem->virt_addr)
140 return ERR_PTR(-ENXIO);
145 static void pmem_detach_disk(struct pmem_device *pmem)
147 del_gendisk(pmem->pmem_disk);
148 put_disk(pmem->pmem_disk);
149 blk_cleanup_queue(pmem->pmem_queue);
152 static int pmem_attach_disk(struct nd_namespace_common *ndns,
153 struct pmem_device *pmem)
155 struct gendisk *disk;
157 pmem->pmem_queue = blk_alloc_queue(GFP_KERNEL);
158 if (!pmem->pmem_queue)
161 blk_queue_make_request(pmem->pmem_queue, pmem_make_request);
162 blk_queue_physical_block_size(pmem->pmem_queue, PAGE_SIZE);
163 blk_queue_max_hw_sectors(pmem->pmem_queue, UINT_MAX);
164 blk_queue_bounce_limit(pmem->pmem_queue, BLK_BOUNCE_ANY);
165 queue_flag_set_unlocked(QUEUE_FLAG_NONROT, pmem->pmem_queue);
167 disk = alloc_disk(0);
169 blk_cleanup_queue(pmem->pmem_queue);
173 disk->major = pmem_major;
174 disk->first_minor = 0;
175 disk->fops = &pmem_fops;
176 disk->private_data = pmem;
177 disk->queue = pmem->pmem_queue;
178 disk->flags = GENHD_FL_EXT_DEVT;
179 nvdimm_namespace_disk_name(ndns, disk->disk_name);
180 disk->driverfs_dev = &ndns->dev;
181 set_capacity(disk, pmem->size >> 9);
182 pmem->pmem_disk = disk;
185 revalidate_disk(disk);
190 static int pmem_rw_bytes(struct nd_namespace_common *ndns,
191 resource_size_t offset, void *buf, size_t size, int rw)
193 struct pmem_device *pmem = dev_get_drvdata(ndns->claim);
195 if (unlikely(offset + size > pmem->size)) {
196 dev_WARN_ONCE(&ndns->dev, 1, "request out of range\n");
201 memcpy_from_pmem(buf, pmem->virt_addr + offset, size);
203 memcpy_to_pmem(pmem->virt_addr + offset, buf, size);
210 static int nd_pmem_probe(struct device *dev)
212 struct nd_region *nd_region = to_nd_region(dev->parent);
213 struct nd_namespace_common *ndns;
214 struct nd_namespace_io *nsio;
215 struct pmem_device *pmem;
217 ndns = nvdimm_namespace_common_probe(dev);
219 return PTR_ERR(ndns);
221 nsio = to_nd_namespace_io(&ndns->dev);
222 pmem = pmem_alloc(dev, &nsio->res, nd_region->id);
224 return PTR_ERR(pmem);
226 dev_set_drvdata(dev, pmem);
227 ndns->rw_bytes = pmem_rw_bytes;
230 return nvdimm_namespace_attach_btt(ndns);
232 if (nd_btt_probe(ndns, pmem) == 0)
233 /* we'll come back as btt-pmem */
235 return pmem_attach_disk(ndns, pmem);
238 static int nd_pmem_remove(struct device *dev)
240 struct pmem_device *pmem = dev_get_drvdata(dev);
243 nvdimm_namespace_detach_btt(to_nd_btt(dev)->ndns);
245 pmem_detach_disk(pmem);
250 MODULE_ALIAS("pmem");
251 MODULE_ALIAS_ND_DEVICE(ND_DEVICE_NAMESPACE_IO);
252 MODULE_ALIAS_ND_DEVICE(ND_DEVICE_NAMESPACE_PMEM);
253 static struct nd_device_driver nd_pmem_driver = {
254 .probe = nd_pmem_probe,
255 .remove = nd_pmem_remove,
259 .type = ND_DRIVER_NAMESPACE_IO | ND_DRIVER_NAMESPACE_PMEM,
262 static int __init pmem_init(void)
266 pmem_major = register_blkdev(0, "pmem");
270 error = nd_driver_register(&nd_pmem_driver);
272 unregister_blkdev(pmem_major, "pmem");
278 module_init(pmem_init);
280 static void pmem_exit(void)
282 driver_unregister(&nd_pmem_driver.drv);
283 unregister_blkdev(pmem_major, "pmem");
285 module_exit(pmem_exit);
287 MODULE_AUTHOR("Ross Zwisler <ross.zwisler@linux.intel.com>");
288 MODULE_LICENSE("GPL v2");