]>
Commit | Line | Data |
---|---|---|
9e853f23 RZ |
1 | /* |
2 | * Persistent Memory Driver | |
3 | * | |
4 | * Copyright (c) 2014, 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 | ||
27 | #define PMEM_MINORS 16 | |
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 | static atomic_t pmem_index; | |
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 | ||
49 | if (rw == READ) { | |
50 | memcpy(mem + off, pmem->virt_addr + pmem_off, len); | |
51 | flush_dcache_page(page); | |
52 | } else { | |
53 | flush_dcache_page(page); | |
54 | memcpy(pmem->virt_addr + pmem_off, mem + off, len); | |
55 | } | |
56 | ||
57 | kunmap_atomic(mem); | |
58 | } | |
59 | ||
60 | static void pmem_make_request(struct request_queue *q, struct bio *bio) | |
61 | { | |
62 | struct block_device *bdev = bio->bi_bdev; | |
63 | struct pmem_device *pmem = bdev->bd_disk->private_data; | |
64 | int rw; | |
65 | struct bio_vec bvec; | |
66 | sector_t sector; | |
67 | struct bvec_iter iter; | |
68 | int err = 0; | |
69 | ||
70 | if (bio_end_sector(bio) > get_capacity(bdev->bd_disk)) { | |
71 | err = -EIO; | |
72 | goto out; | |
73 | } | |
74 | ||
75 | BUG_ON(bio->bi_rw & REQ_DISCARD); | |
76 | ||
77 | rw = bio_data_dir(bio); | |
78 | sector = bio->bi_iter.bi_sector; | |
79 | bio_for_each_segment(bvec, bio, iter) { | |
80 | pmem_do_bvec(pmem, bvec.bv_page, bvec.bv_len, bvec.bv_offset, | |
81 | rw, sector); | |
82 | sector += bvec.bv_len >> 9; | |
83 | } | |
84 | ||
85 | out: | |
86 | bio_endio(bio, err); | |
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 | page_endio(page, rw & WRITE, 0); | |
96 | ||
97 | return 0; | |
98 | } | |
99 | ||
100 | static long pmem_direct_access(struct block_device *bdev, sector_t sector, | |
101 | void **kaddr, unsigned long *pfn, long size) | |
102 | { | |
103 | struct pmem_device *pmem = bdev->bd_disk->private_data; | |
104 | size_t offset = sector << 9; | |
105 | ||
106 | if (!pmem) | |
107 | return -ENODEV; | |
108 | ||
109 | *kaddr = pmem->virt_addr + offset; | |
110 | *pfn = (pmem->phys_addr + offset) >> PAGE_SHIFT; | |
111 | ||
112 | return pmem->size - offset; | |
113 | } | |
114 | ||
115 | static const struct block_device_operations pmem_fops = { | |
116 | .owner = THIS_MODULE, | |
117 | .rw_page = pmem_rw_page, | |
118 | .direct_access = pmem_direct_access, | |
119 | }; | |
120 | ||
121 | static struct pmem_device *pmem_alloc(struct device *dev, struct resource *res) | |
122 | { | |
123 | struct pmem_device *pmem; | |
124 | struct gendisk *disk; | |
125 | int idx, 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")) { | |
4c1eaa23 | 137 | dev_warn(dev, "could not reserve region [0x%pa:0x%zx]\n", &pmem->phys_addr, pmem->size); |
9e853f23 RZ |
138 | goto out_free_dev; |
139 | } | |
140 | ||
141 | /* | |
142 | * Map the memory as non-cachable, as we can't write back the contents | |
143 | * of the CPU caches in case of a crash. | |
144 | */ | |
145 | err = -ENOMEM; | |
146 | pmem->virt_addr = ioremap_nocache(pmem->phys_addr, pmem->size); | |
147 | if (!pmem->virt_addr) | |
148 | goto out_release_region; | |
149 | ||
150 | pmem->pmem_queue = blk_alloc_queue(GFP_KERNEL); | |
151 | if (!pmem->pmem_queue) | |
152 | goto out_unmap; | |
153 | ||
154 | blk_queue_make_request(pmem->pmem_queue, pmem_make_request); | |
155 | blk_queue_max_hw_sectors(pmem->pmem_queue, 1024); | |
156 | blk_queue_bounce_limit(pmem->pmem_queue, BLK_BOUNCE_ANY); | |
157 | ||
158 | disk = alloc_disk(PMEM_MINORS); | |
159 | if (!disk) | |
160 | goto out_free_queue; | |
161 | ||
162 | idx = atomic_inc_return(&pmem_index) - 1; | |
163 | ||
164 | disk->major = pmem_major; | |
165 | disk->first_minor = PMEM_MINORS * idx; | |
166 | disk->fops = &pmem_fops; | |
167 | disk->private_data = pmem; | |
168 | disk->queue = pmem->pmem_queue; | |
169 | disk->flags = GENHD_FL_EXT_DEVT; | |
170 | sprintf(disk->disk_name, "pmem%d", idx); | |
171 | disk->driverfs_dev = dev; | |
172 | set_capacity(disk, pmem->size >> 9); | |
173 | pmem->pmem_disk = disk; | |
174 | ||
175 | add_disk(disk); | |
176 | ||
177 | return pmem; | |
178 | ||
179 | out_free_queue: | |
180 | blk_cleanup_queue(pmem->pmem_queue); | |
181 | out_unmap: | |
182 | iounmap(pmem->virt_addr); | |
183 | out_release_region: | |
184 | release_mem_region(pmem->phys_addr, pmem->size); | |
185 | out_free_dev: | |
186 | kfree(pmem); | |
187 | out: | |
188 | return ERR_PTR(err); | |
189 | } | |
190 | ||
191 | static void pmem_free(struct pmem_device *pmem) | |
192 | { | |
193 | del_gendisk(pmem->pmem_disk); | |
194 | put_disk(pmem->pmem_disk); | |
195 | blk_cleanup_queue(pmem->pmem_queue); | |
196 | iounmap(pmem->virt_addr); | |
197 | release_mem_region(pmem->phys_addr, pmem->size); | |
198 | kfree(pmem); | |
199 | } | |
200 | ||
201 | static int pmem_probe(struct platform_device *pdev) | |
202 | { | |
203 | struct pmem_device *pmem; | |
204 | struct resource *res; | |
205 | ||
206 | if (WARN_ON(pdev->num_resources > 1)) | |
207 | return -ENXIO; | |
208 | ||
209 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
210 | if (!res) | |
211 | return -ENXIO; | |
212 | ||
213 | pmem = pmem_alloc(&pdev->dev, res); | |
214 | if (IS_ERR(pmem)) | |
215 | return PTR_ERR(pmem); | |
216 | ||
217 | platform_set_drvdata(pdev, pmem); | |
218 | ||
219 | return 0; | |
220 | } | |
221 | ||
222 | static int pmem_remove(struct platform_device *pdev) | |
223 | { | |
224 | struct pmem_device *pmem = platform_get_drvdata(pdev); | |
225 | ||
226 | pmem_free(pmem); | |
227 | return 0; | |
228 | } | |
229 | ||
230 | static struct platform_driver pmem_driver = { | |
231 | .probe = pmem_probe, | |
232 | .remove = pmem_remove, | |
233 | .driver = { | |
234 | .owner = THIS_MODULE, | |
235 | .name = "pmem", | |
236 | }, | |
237 | }; | |
238 | ||
239 | static int __init pmem_init(void) | |
240 | { | |
241 | int error; | |
242 | ||
243 | pmem_major = register_blkdev(0, "pmem"); | |
244 | if (pmem_major < 0) | |
245 | return pmem_major; | |
246 | ||
247 | error = platform_driver_register(&pmem_driver); | |
248 | if (error) | |
249 | unregister_blkdev(pmem_major, "pmem"); | |
250 | return error; | |
251 | } | |
252 | module_init(pmem_init); | |
253 | ||
254 | static void pmem_exit(void) | |
255 | { | |
256 | platform_driver_unregister(&pmem_driver); | |
257 | unregister_blkdev(pmem_major, "pmem"); | |
258 | } | |
259 | module_exit(pmem_exit); | |
260 | ||
261 | MODULE_AUTHOR("Ross Zwisler <ross.zwisler@linux.intel.com>"); | |
262 | MODULE_LICENSE("GPL v2"); |