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Merge branch 'fixes' of git://ftp.arm.linux.org.uk/~rmk/linux-arm
[karo-tx-linux.git] / 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/memory_hotplug.h>
25 #include <linux/moduleparam.h>
26 #include <linux/vmalloc.h>
27 #include <linux/slab.h>
28 #include <linux/pmem.h>
29 #include <linux/nd.h>
30 #include "pfn.h"
31 #include "nd.h"
32
33 struct pmem_device {
34         struct request_queue    *pmem_queue;
35         struct gendisk          *pmem_disk;
36         struct nd_namespace_common *ndns;
37
38         /* One contiguous memory region per device */
39         phys_addr_t             phys_addr;
40         /* when non-zero this device is hosting a 'pfn' instance */
41         phys_addr_t             data_offset;
42         void __pmem             *virt_addr;
43         size_t                  size;
44 };
45
46 static int pmem_major;
47
48 static void pmem_do_bvec(struct pmem_device *pmem, struct page *page,
49                         unsigned int len, unsigned int off, int rw,
50                         sector_t sector)
51 {
52         void *mem = kmap_atomic(page);
53         phys_addr_t pmem_off = sector * 512 + pmem->data_offset;
54         void __pmem *pmem_addr = pmem->virt_addr + pmem_off;
55
56         if (rw == READ) {
57                 memcpy_from_pmem(mem + off, pmem_addr, len);
58                 flush_dcache_page(page);
59         } else {
60                 flush_dcache_page(page);
61                 memcpy_to_pmem(pmem_addr, mem + off, len);
62         }
63
64         kunmap_atomic(mem);
65 }
66
67 static void pmem_make_request(struct request_queue *q, struct bio *bio)
68 {
69         bool do_acct;
70         unsigned long start;
71         struct bio_vec bvec;
72         struct bvec_iter iter;
73         struct block_device *bdev = bio->bi_bdev;
74         struct pmem_device *pmem = bdev->bd_disk->private_data;
75
76         do_acct = nd_iostat_start(bio, &start);
77         bio_for_each_segment(bvec, bio, iter)
78                 pmem_do_bvec(pmem, bvec.bv_page, bvec.bv_len, bvec.bv_offset,
79                                 bio_data_dir(bio), iter.bi_sector);
80         if (do_acct)
81                 nd_iostat_end(bio, start);
82
83         if (bio_data_dir(bio))
84                 wmb_pmem();
85
86         bio_endio(bio);
87 }
88
89 static int pmem_rw_page(struct block_device *bdev, sector_t sector,
90                        struct page *page, int rw)
91 {
92         struct pmem_device *pmem = bdev->bd_disk->private_data;
93
94         pmem_do_bvec(pmem, page, PAGE_CACHE_SIZE, 0, rw, sector);
95         if (rw & WRITE)
96                 wmb_pmem();
97         page_endio(page, rw & WRITE, 0);
98
99         return 0;
100 }
101
102 static long pmem_direct_access(struct block_device *bdev, sector_t sector,
103                       void __pmem **kaddr, unsigned long *pfn)
104 {
105         struct pmem_device *pmem = bdev->bd_disk->private_data;
106         resource_size_t offset = sector * 512 + pmem->data_offset;
107         resource_size_t size;
108
109         if (pmem->data_offset) {
110                 /*
111                  * Limit the direct_access() size to what is covered by
112                  * the memmap
113                  */
114                 size = (pmem->size - offset) & ~ND_PFN_MASK;
115         } else
116                 size = pmem->size - offset;
117
118         /* FIXME convert DAX to comprehend that this mapping has a lifetime */
119         *kaddr = pmem->virt_addr + offset;
120         *pfn = (pmem->phys_addr + offset) >> PAGE_SHIFT;
121
122         return size;
123 }
124
125 static const struct block_device_operations pmem_fops = {
126         .owner =                THIS_MODULE,
127         .rw_page =              pmem_rw_page,
128         .direct_access =        pmem_direct_access,
129         .revalidate_disk =      nvdimm_revalidate_disk,
130 };
131
132 static struct pmem_device *pmem_alloc(struct device *dev,
133                 struct resource *res, int id)
134 {
135         struct pmem_device *pmem;
136
137         pmem = devm_kzalloc(dev, sizeof(*pmem), GFP_KERNEL);
138         if (!pmem)
139                 return ERR_PTR(-ENOMEM);
140
141         pmem->phys_addr = res->start;
142         pmem->size = resource_size(res);
143         if (!arch_has_wmb_pmem())
144                 dev_warn(dev, "unable to guarantee persistence of writes\n");
145
146         if (!devm_request_mem_region(dev, pmem->phys_addr, pmem->size,
147                         dev_name(dev))) {
148                 dev_warn(dev, "could not reserve region [0x%pa:0x%zx]\n",
149                                 &pmem->phys_addr, pmem->size);
150                 return ERR_PTR(-EBUSY);
151         }
152
153         if (pmem_should_map_pages(dev)) {
154                 void *addr = devm_memremap_pages(dev, res);
155
156                 if (IS_ERR(addr))
157                         return addr;
158                 pmem->virt_addr = (void __pmem *) addr;
159         } else {
160                 pmem->virt_addr = memremap_pmem(dev, pmem->phys_addr,
161                                 pmem->size);
162                 if (!pmem->virt_addr)
163                         return ERR_PTR(-ENXIO);
164         }
165
166         return pmem;
167 }
168
169 static void pmem_detach_disk(struct pmem_device *pmem)
170 {
171         if (!pmem->pmem_disk)
172                 return;
173
174         del_gendisk(pmem->pmem_disk);
175         put_disk(pmem->pmem_disk);
176         blk_cleanup_queue(pmem->pmem_queue);
177 }
178
179 static int pmem_attach_disk(struct device *dev,
180                 struct nd_namespace_common *ndns, struct pmem_device *pmem)
181 {
182         struct gendisk *disk;
183
184         pmem->pmem_queue = blk_alloc_queue(GFP_KERNEL);
185         if (!pmem->pmem_queue)
186                 return -ENOMEM;
187
188         blk_queue_make_request(pmem->pmem_queue, pmem_make_request);
189         blk_queue_physical_block_size(pmem->pmem_queue, PAGE_SIZE);
190         blk_queue_max_hw_sectors(pmem->pmem_queue, UINT_MAX);
191         blk_queue_bounce_limit(pmem->pmem_queue, BLK_BOUNCE_ANY);
192         queue_flag_set_unlocked(QUEUE_FLAG_NONROT, pmem->pmem_queue);
193
194         disk = alloc_disk(0);
195         if (!disk) {
196                 blk_cleanup_queue(pmem->pmem_queue);
197                 return -ENOMEM;
198         }
199
200         disk->major             = pmem_major;
201         disk->first_minor       = 0;
202         disk->fops              = &pmem_fops;
203         disk->private_data      = pmem;
204         disk->queue             = pmem->pmem_queue;
205         disk->flags             = GENHD_FL_EXT_DEVT;
206         nvdimm_namespace_disk_name(ndns, disk->disk_name);
207         disk->driverfs_dev = dev;
208         set_capacity(disk, (pmem->size - pmem->data_offset) / 512);
209         pmem->pmem_disk = disk;
210
211         add_disk(disk);
212         revalidate_disk(disk);
213
214         return 0;
215 }
216
217 static int pmem_rw_bytes(struct nd_namespace_common *ndns,
218                 resource_size_t offset, void *buf, size_t size, int rw)
219 {
220         struct pmem_device *pmem = dev_get_drvdata(ndns->claim);
221
222         if (unlikely(offset + size > pmem->size)) {
223                 dev_WARN_ONCE(&ndns->dev, 1, "request out of range\n");
224                 return -EFAULT;
225         }
226
227         if (rw == READ)
228                 memcpy_from_pmem(buf, pmem->virt_addr + offset, size);
229         else {
230                 memcpy_to_pmem(pmem->virt_addr + offset, buf, size);
231                 wmb_pmem();
232         }
233
234         return 0;
235 }
236
237 static int nd_pfn_init(struct nd_pfn *nd_pfn)
238 {
239         struct nd_pfn_sb *pfn_sb = kzalloc(sizeof(*pfn_sb), GFP_KERNEL);
240         struct pmem_device *pmem = dev_get_drvdata(&nd_pfn->dev);
241         struct nd_namespace_common *ndns = nd_pfn->ndns;
242         struct nd_region *nd_region;
243         unsigned long npfns;
244         phys_addr_t offset;
245         u64 checksum;
246         int rc;
247
248         if (!pfn_sb)
249                 return -ENOMEM;
250
251         nd_pfn->pfn_sb = pfn_sb;
252         rc = nd_pfn_validate(nd_pfn);
253         if (rc == 0 || rc == -EBUSY)
254                 return rc;
255
256         /* section alignment for simple hotplug */
257         if (nvdimm_namespace_capacity(ndns) < ND_PFN_ALIGN
258                         || pmem->phys_addr & ND_PFN_MASK)
259                 return -ENODEV;
260
261         nd_region = to_nd_region(nd_pfn->dev.parent);
262         if (nd_region->ro) {
263                 dev_info(&nd_pfn->dev,
264                                 "%s is read-only, unable to init metadata\n",
265                                 dev_name(&nd_region->dev));
266                 goto err;
267         }
268
269         memset(pfn_sb, 0, sizeof(*pfn_sb));
270         npfns = (pmem->size - SZ_8K) / SZ_4K;
271         /*
272          * Note, we use 64 here for the standard size of struct page,
273          * debugging options may cause it to be larger in which case the
274          * implementation will limit the pfns advertised through
275          * ->direct_access() to those that are included in the memmap.
276          */
277         if (nd_pfn->mode == PFN_MODE_PMEM)
278                 offset = ALIGN(SZ_8K + 64 * npfns, PMD_SIZE);
279         else if (nd_pfn->mode == PFN_MODE_RAM)
280                 offset = SZ_8K;
281         else
282                 goto err;
283
284         npfns = (pmem->size - offset) / SZ_4K;
285         pfn_sb->mode = cpu_to_le32(nd_pfn->mode);
286         pfn_sb->dataoff = cpu_to_le64(offset);
287         pfn_sb->npfns = cpu_to_le64(npfns);
288         memcpy(pfn_sb->signature, PFN_SIG, PFN_SIG_LEN);
289         memcpy(pfn_sb->uuid, nd_pfn->uuid, 16);
290         pfn_sb->version_major = cpu_to_le16(1);
291         checksum = nd_sb_checksum((struct nd_gen_sb *) pfn_sb);
292         pfn_sb->checksum = cpu_to_le64(checksum);
293
294         rc = nvdimm_write_bytes(ndns, SZ_4K, pfn_sb, sizeof(*pfn_sb));
295         if (rc)
296                 goto err;
297
298         return 0;
299  err:
300         nd_pfn->pfn_sb = NULL;
301         kfree(pfn_sb);
302         return -ENXIO;
303 }
304
305 static int nvdimm_namespace_detach_pfn(struct nd_namespace_common *ndns)
306 {
307         struct nd_pfn *nd_pfn = to_nd_pfn(ndns->claim);
308         struct pmem_device *pmem;
309
310         /* free pmem disk */
311         pmem = dev_get_drvdata(&nd_pfn->dev);
312         pmem_detach_disk(pmem);
313
314         /* release nd_pfn resources */
315         kfree(nd_pfn->pfn_sb);
316         nd_pfn->pfn_sb = NULL;
317
318         return 0;
319 }
320
321 static int nvdimm_namespace_attach_pfn(struct nd_namespace_common *ndns)
322 {
323         struct nd_namespace_io *nsio = to_nd_namespace_io(&ndns->dev);
324         struct nd_pfn *nd_pfn = to_nd_pfn(ndns->claim);
325         struct device *dev = &nd_pfn->dev;
326         struct vmem_altmap *altmap;
327         struct nd_region *nd_region;
328         struct nd_pfn_sb *pfn_sb;
329         struct pmem_device *pmem;
330         phys_addr_t offset;
331         int rc;
332
333         if (!nd_pfn->uuid || !nd_pfn->ndns)
334                 return -ENODEV;
335
336         nd_region = to_nd_region(dev->parent);
337         rc = nd_pfn_init(nd_pfn);
338         if (rc)
339                 return rc;
340
341         if (PAGE_SIZE != SZ_4K) {
342                 dev_err(dev, "only supported on systems with 4K PAGE_SIZE\n");
343                 return -ENXIO;
344         }
345         if (nsio->res.start & ND_PFN_MASK) {
346                 dev_err(dev, "%s not memory hotplug section aligned\n",
347                                 dev_name(&ndns->dev));
348                 return -ENXIO;
349         }
350
351         pfn_sb = nd_pfn->pfn_sb;
352         offset = le64_to_cpu(pfn_sb->dataoff);
353         nd_pfn->mode = le32_to_cpu(nd_pfn->pfn_sb->mode);
354         if (nd_pfn->mode == PFN_MODE_RAM) {
355                 if (offset != SZ_8K)
356                         return -EINVAL;
357                 nd_pfn->npfns = le64_to_cpu(pfn_sb->npfns);
358                 altmap = NULL;
359         } else {
360                 rc = -ENXIO;
361                 goto err;
362         }
363
364         /* establish pfn range for lookup, and switch to direct map */
365         pmem = dev_get_drvdata(dev);
366         memunmap_pmem(dev, pmem->virt_addr);
367         pmem->virt_addr = (void __pmem *)devm_memremap_pages(dev, &nsio->res);
368         if (IS_ERR(pmem->virt_addr)) {
369                 rc = PTR_ERR(pmem->virt_addr);
370                 goto err;
371         }
372
373         /* attach pmem disk in "pfn-mode" */
374         pmem->data_offset = offset;
375         rc = pmem_attach_disk(dev, ndns, pmem);
376         if (rc)
377                 goto err;
378
379         return rc;
380  err:
381         nvdimm_namespace_detach_pfn(ndns);
382         return rc;
383 }
384
385 static int nd_pmem_probe(struct device *dev)
386 {
387         struct nd_region *nd_region = to_nd_region(dev->parent);
388         struct nd_namespace_common *ndns;
389         struct nd_namespace_io *nsio;
390         struct pmem_device *pmem;
391
392         ndns = nvdimm_namespace_common_probe(dev);
393         if (IS_ERR(ndns))
394                 return PTR_ERR(ndns);
395
396         nsio = to_nd_namespace_io(&ndns->dev);
397         pmem = pmem_alloc(dev, &nsio->res, nd_region->id);
398         if (IS_ERR(pmem))
399                 return PTR_ERR(pmem);
400
401         pmem->ndns = ndns;
402         dev_set_drvdata(dev, pmem);
403         ndns->rw_bytes = pmem_rw_bytes;
404
405         if (is_nd_btt(dev))
406                 return nvdimm_namespace_attach_btt(ndns);
407
408         if (is_nd_pfn(dev))
409                 return nvdimm_namespace_attach_pfn(ndns);
410
411         if (nd_btt_probe(ndns, pmem) == 0) {
412                 /* we'll come back as btt-pmem */
413                 return -ENXIO;
414         }
415
416         if (nd_pfn_probe(ndns, pmem) == 0) {
417                 /* we'll come back as pfn-pmem */
418                 return -ENXIO;
419         }
420
421         return pmem_attach_disk(dev, ndns, pmem);
422 }
423
424 static int nd_pmem_remove(struct device *dev)
425 {
426         struct pmem_device *pmem = dev_get_drvdata(dev);
427
428         if (is_nd_btt(dev))
429                 nvdimm_namespace_detach_btt(pmem->ndns);
430         else if (is_nd_pfn(dev))
431                 nvdimm_namespace_detach_pfn(pmem->ndns);
432         else
433                 pmem_detach_disk(pmem);
434
435         return 0;
436 }
437
438 MODULE_ALIAS("pmem");
439 MODULE_ALIAS_ND_DEVICE(ND_DEVICE_NAMESPACE_IO);
440 MODULE_ALIAS_ND_DEVICE(ND_DEVICE_NAMESPACE_PMEM);
441 static struct nd_device_driver nd_pmem_driver = {
442         .probe = nd_pmem_probe,
443         .remove = nd_pmem_remove,
444         .drv = {
445                 .name = "nd_pmem",
446         },
447         .type = ND_DRIVER_NAMESPACE_IO | ND_DRIVER_NAMESPACE_PMEM,
448 };
449
450 static int __init pmem_init(void)
451 {
452         int error;
453
454         pmem_major = register_blkdev(0, "pmem");
455         if (pmem_major < 0)
456                 return pmem_major;
457
458         error = nd_driver_register(&nd_pmem_driver);
459         if (error) {
460                 unregister_blkdev(pmem_major, "pmem");
461                 return error;
462         }
463
464         return 0;
465 }
466 module_init(pmem_init);
467
468 static void pmem_exit(void)
469 {
470         driver_unregister(&nd_pmem_driver.drv);
471         unregister_blkdev(pmem_major, "pmem");
472 }
473 module_exit(pmem_exit);
474
475 MODULE_AUTHOR("Ross Zwisler <ross.zwisler@linux.intel.com>");
476 MODULE_LICENSE("GPL v2");