Commit | Line | Data |
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c672528a CC |
1 | /* |
2 | * Copyright (C) 2012 Google, Inc. | |
3 | * | |
4 | * This software is licensed under the terms of the GNU General Public | |
5 | * License version 2, as published by the Free Software Foundation, and | |
6 | * may be copied, distributed, and modified under those terms. | |
7 | * | |
8 | * This program is distributed in the hope that it will be useful, | |
9 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
10 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
11 | * GNU General Public License for more details. | |
12 | * | |
13 | */ | |
14 | ||
404a6043 CC |
15 | #include <linux/device.h> |
16 | #include <linux/err.h> | |
c672528a CC |
17 | #include <linux/errno.h> |
18 | #include <linux/kernel.h> | |
19 | #include <linux/init.h> | |
20 | #include <linux/io.h> | |
404a6043 CC |
21 | #include <linux/list.h> |
22 | #include <linux/memblock.h> | |
9cc05ad9 | 23 | #include <linux/rslib.h> |
c672528a | 24 | #include <linux/slab.h> |
404a6043 | 25 | #include <linux/vmalloc.h> |
cddb8751 | 26 | #include <linux/pstore_ram.h> |
24c3d2f3 | 27 | #include <asm/page.h> |
c672528a | 28 | |
c672528a CC |
29 | struct persistent_ram_buffer { |
30 | uint32_t sig; | |
808d0387 CC |
31 | atomic_t start; |
32 | atomic_t size; | |
c672528a CC |
33 | uint8_t data[0]; |
34 | }; | |
35 | ||
36 | #define PERSISTENT_RAM_SIG (0x43474244) /* DBGC */ | |
37 | ||
808d0387 CC |
38 | static inline size_t buffer_size(struct persistent_ram_zone *prz) |
39 | { | |
40 | return atomic_read(&prz->buffer->size); | |
41 | } | |
42 | ||
43 | static inline size_t buffer_start(struct persistent_ram_zone *prz) | |
44 | { | |
45 | return atomic_read(&prz->buffer->start); | |
46 | } | |
47 | ||
48 | /* increase and wrap the start pointer, returning the old value */ | |
49 | static inline size_t buffer_start_add(struct persistent_ram_zone *prz, size_t a) | |
50 | { | |
51 | int old; | |
52 | int new; | |
53 | ||
54 | do { | |
55 | old = atomic_read(&prz->buffer->start); | |
56 | new = old + a; | |
57 | while (unlikely(new > prz->buffer_size)) | |
58 | new -= prz->buffer_size; | |
59 | } while (atomic_cmpxchg(&prz->buffer->start, old, new) != old); | |
60 | ||
61 | return old; | |
62 | } | |
63 | ||
64 | /* increase the size counter until it hits the max size */ | |
65 | static inline void buffer_size_add(struct persistent_ram_zone *prz, size_t a) | |
66 | { | |
67 | size_t old; | |
68 | size_t new; | |
69 | ||
70 | if (atomic_read(&prz->buffer->size) == prz->buffer_size) | |
71 | return; | |
72 | ||
73 | do { | |
74 | old = atomic_read(&prz->buffer->size); | |
75 | new = old + a; | |
76 | if (new > prz->buffer_size) | |
77 | new = prz->buffer_size; | |
78 | } while (atomic_cmpxchg(&prz->buffer->size, old, new) != old); | |
79 | } | |
80 | ||
a15d0b36 | 81 | static void notrace persistent_ram_encode_rs8(struct persistent_ram_zone *prz, |
c672528a CC |
82 | uint8_t *data, size_t len, uint8_t *ecc) |
83 | { | |
84 | int i; | |
9cc05ad9 CC |
85 | uint16_t par[prz->ecc_size]; |
86 | ||
c672528a CC |
87 | /* Initialize the parity buffer */ |
88 | memset(par, 0, sizeof(par)); | |
89 | encode_rs8(prz->rs_decoder, data, len, par, 0); | |
9cc05ad9 | 90 | for (i = 0; i < prz->ecc_size; i++) |
c672528a CC |
91 | ecc[i] = par[i]; |
92 | } | |
93 | ||
94 | static int persistent_ram_decode_rs8(struct persistent_ram_zone *prz, | |
95 | void *data, size_t len, uint8_t *ecc) | |
96 | { | |
97 | int i; | |
9cc05ad9 CC |
98 | uint16_t par[prz->ecc_size]; |
99 | ||
100 | for (i = 0; i < prz->ecc_size; i++) | |
c672528a CC |
101 | par[i] = ecc[i]; |
102 | return decode_rs8(prz->rs_decoder, data, par, len, | |
103 | NULL, 0, NULL, 0, NULL); | |
104 | } | |
c672528a | 105 | |
a15d0b36 | 106 | static void notrace persistent_ram_update_ecc(struct persistent_ram_zone *prz, |
808d0387 | 107 | unsigned int start, unsigned int count) |
c672528a CC |
108 | { |
109 | struct persistent_ram_buffer *buffer = prz->buffer; | |
c672528a CC |
110 | uint8_t *buffer_end = buffer->data + prz->buffer_size; |
111 | uint8_t *block; | |
112 | uint8_t *par; | |
9cc05ad9 CC |
113 | int ecc_block_size = prz->ecc_block_size; |
114 | int ecc_size = prz->ecc_size; | |
115 | int size = prz->ecc_block_size; | |
116 | ||
c1743cbc | 117 | if (!prz->ecc_size) |
9cc05ad9 CC |
118 | return; |
119 | ||
808d0387 CC |
120 | block = buffer->data + (start & ~(ecc_block_size - 1)); |
121 | par = prz->par_buffer + (start / ecc_block_size) * prz->ecc_size; | |
122 | ||
c672528a | 123 | do { |
9cc05ad9 | 124 | if (block + ecc_block_size > buffer_end) |
c672528a CC |
125 | size = buffer_end - block; |
126 | persistent_ram_encode_rs8(prz, block, size, par); | |
9cc05ad9 CC |
127 | block += ecc_block_size; |
128 | par += ecc_size; | |
808d0387 | 129 | } while (block < buffer->data + start + count); |
c672528a CC |
130 | } |
131 | ||
9cc05ad9 | 132 | static void persistent_ram_update_header_ecc(struct persistent_ram_zone *prz) |
c672528a | 133 | { |
c672528a CC |
134 | struct persistent_ram_buffer *buffer = prz->buffer; |
135 | ||
c1743cbc | 136 | if (!prz->ecc_size) |
9cc05ad9 CC |
137 | return; |
138 | ||
c672528a CC |
139 | persistent_ram_encode_rs8(prz, (uint8_t *)buffer, sizeof(*buffer), |
140 | prz->par_header); | |
c672528a CC |
141 | } |
142 | ||
9cc05ad9 | 143 | static void persistent_ram_ecc_old(struct persistent_ram_zone *prz) |
c672528a CC |
144 | { |
145 | struct persistent_ram_buffer *buffer = prz->buffer; | |
c672528a CC |
146 | uint8_t *block; |
147 | uint8_t *par; | |
148 | ||
c1743cbc | 149 | if (!prz->ecc_size) |
9cc05ad9 CC |
150 | return; |
151 | ||
c672528a CC |
152 | block = buffer->data; |
153 | par = prz->par_buffer; | |
808d0387 | 154 | while (block < buffer->data + buffer_size(prz)) { |
c672528a | 155 | int numerr; |
9cc05ad9 | 156 | int size = prz->ecc_block_size; |
c672528a CC |
157 | if (block + size > buffer->data + prz->buffer_size) |
158 | size = buffer->data + prz->buffer_size - block; | |
159 | numerr = persistent_ram_decode_rs8(prz, block, size, par); | |
160 | if (numerr > 0) { | |
9cc05ad9 | 161 | pr_devel("persistent_ram: error in block %p, %d\n", |
c672528a | 162 | block, numerr); |
c672528a CC |
163 | prz->corrected_bytes += numerr; |
164 | } else if (numerr < 0) { | |
9cc05ad9 | 165 | pr_devel("persistent_ram: uncorrectable error in block %p\n", |
c672528a | 166 | block); |
c672528a CC |
167 | prz->bad_blocks++; |
168 | } | |
9cc05ad9 CC |
169 | block += prz->ecc_block_size; |
170 | par += prz->ecc_size; | |
171 | } | |
172 | } | |
173 | ||
5ca5d4e6 AV |
174 | static int persistent_ram_init_ecc(struct persistent_ram_zone *prz, |
175 | int ecc_size) | |
9cc05ad9 CC |
176 | { |
177 | int numerr; | |
178 | struct persistent_ram_buffer *buffer = prz->buffer; | |
179 | int ecc_blocks; | |
1e6a9e56 | 180 | size_t ecc_total; |
4a53ffae AV |
181 | int ecc_symsize = 8; |
182 | int ecc_poly = 0x11d; | |
9cc05ad9 | 183 | |
c1743cbc | 184 | if (!ecc_size) |
9cc05ad9 CC |
185 | return 0; |
186 | ||
187 | prz->ecc_block_size = 128; | |
5ca5d4e6 | 188 | prz->ecc_size = ecc_size; |
9cc05ad9 CC |
189 | |
190 | ecc_blocks = DIV_ROUND_UP(prz->buffer_size, prz->ecc_block_size); | |
1e6a9e56 AV |
191 | ecc_total = (ecc_blocks + 1) * prz->ecc_size; |
192 | if (ecc_total >= prz->buffer_size) { | |
193 | pr_err("%s: invalid ecc_size %u (total %zu, buffer size %zu)\n", | |
194 | __func__, prz->ecc_size, ecc_total, prz->buffer_size); | |
9cc05ad9 CC |
195 | return -EINVAL; |
196 | } | |
197 | ||
1e6a9e56 | 198 | prz->buffer_size -= ecc_total; |
9cc05ad9 CC |
199 | prz->par_buffer = buffer->data + prz->buffer_size; |
200 | prz->par_header = prz->par_buffer + ecc_blocks * prz->ecc_size; | |
201 | ||
202 | /* | |
203 | * first consecutive root is 0 | |
204 | * primitive element to generate roots = 1 | |
205 | */ | |
4a53ffae | 206 | prz->rs_decoder = init_rs(ecc_symsize, ecc_poly, 0, 1, prz->ecc_size); |
9cc05ad9 CC |
207 | if (prz->rs_decoder == NULL) { |
208 | pr_info("persistent_ram: init_rs failed\n"); | |
209 | return -EINVAL; | |
c672528a | 210 | } |
9cc05ad9 CC |
211 | |
212 | prz->corrected_bytes = 0; | |
213 | prz->bad_blocks = 0; | |
214 | ||
215 | numerr = persistent_ram_decode_rs8(prz, buffer, sizeof(*buffer), | |
216 | prz->par_header); | |
217 | if (numerr > 0) { | |
218 | pr_info("persistent_ram: error in header, %d\n", numerr); | |
219 | prz->corrected_bytes += numerr; | |
220 | } else if (numerr < 0) { | |
221 | pr_info("persistent_ram: uncorrectable error in header\n"); | |
222 | prz->bad_blocks++; | |
223 | } | |
224 | ||
225 | return 0; | |
226 | } | |
227 | ||
228 | ssize_t persistent_ram_ecc_string(struct persistent_ram_zone *prz, | |
229 | char *str, size_t len) | |
230 | { | |
231 | ssize_t ret; | |
232 | ||
233 | if (prz->corrected_bytes || prz->bad_blocks) | |
234 | ret = snprintf(str, len, "" | |
235 | "\n%d Corrected bytes, %d unrecoverable blocks\n", | |
236 | prz->corrected_bytes, prz->bad_blocks); | |
237 | else | |
238 | ret = snprintf(str, len, "\nNo errors detected\n"); | |
239 | ||
240 | return ret; | |
241 | } | |
242 | ||
a15d0b36 | 243 | static void notrace persistent_ram_update(struct persistent_ram_zone *prz, |
808d0387 | 244 | const void *s, unsigned int start, unsigned int count) |
9cc05ad9 CC |
245 | { |
246 | struct persistent_ram_buffer *buffer = prz->buffer; | |
808d0387 CC |
247 | memcpy(buffer->data + start, s, count); |
248 | persistent_ram_update_ecc(prz, start, count); | |
9cc05ad9 CC |
249 | } |
250 | ||
201e4aca | 251 | void persistent_ram_save_old(struct persistent_ram_zone *prz) |
9cc05ad9 CC |
252 | { |
253 | struct persistent_ram_buffer *buffer = prz->buffer; | |
808d0387 CC |
254 | size_t size = buffer_size(prz); |
255 | size_t start = buffer_start(prz); | |
9cc05ad9 | 256 | |
201e4aca AV |
257 | if (!size) |
258 | return; | |
c672528a | 259 | |
201e4aca AV |
260 | if (!prz->old_log) { |
261 | persistent_ram_ecc_old(prz); | |
262 | prz->old_log = kmalloc(size, GFP_KERNEL); | |
263 | } | |
264 | if (!prz->old_log) { | |
c672528a CC |
265 | pr_err("persistent_ram: failed to allocate buffer\n"); |
266 | return; | |
267 | } | |
268 | ||
808d0387 CC |
269 | prz->old_log_size = size; |
270 | memcpy(prz->old_log, &buffer->data[start], size - start); | |
271 | memcpy(prz->old_log + size - start, &buffer->data[0], start); | |
c672528a CC |
272 | } |
273 | ||
a15d0b36 | 274 | int notrace persistent_ram_write(struct persistent_ram_zone *prz, |
c672528a CC |
275 | const void *s, unsigned int count) |
276 | { | |
277 | int rem; | |
278 | int c = count; | |
808d0387 | 279 | size_t start; |
c672528a | 280 | |
808d0387 | 281 | if (unlikely(c > prz->buffer_size)) { |
c672528a CC |
282 | s += c - prz->buffer_size; |
283 | c = prz->buffer_size; | |
284 | } | |
808d0387 | 285 | |
484dd30e | 286 | buffer_size_add(prz, c); |
808d0387 CC |
287 | |
288 | start = buffer_start_add(prz, c); | |
289 | ||
290 | rem = prz->buffer_size - start; | |
291 | if (unlikely(rem < c)) { | |
292 | persistent_ram_update(prz, s, start, rem); | |
c672528a CC |
293 | s += rem; |
294 | c -= rem; | |
808d0387 | 295 | start = 0; |
c672528a | 296 | } |
808d0387 | 297 | persistent_ram_update(prz, s, start, c); |
c672528a | 298 | |
9cc05ad9 | 299 | persistent_ram_update_header_ecc(prz); |
c672528a CC |
300 | |
301 | return count; | |
302 | } | |
303 | ||
c672528a CC |
304 | size_t persistent_ram_old_size(struct persistent_ram_zone *prz) |
305 | { | |
306 | return prz->old_log_size; | |
307 | } | |
308 | ||
309 | void *persistent_ram_old(struct persistent_ram_zone *prz) | |
310 | { | |
311 | return prz->old_log; | |
312 | } | |
313 | ||
314 | void persistent_ram_free_old(struct persistent_ram_zone *prz) | |
315 | { | |
316 | kfree(prz->old_log); | |
317 | prz->old_log = NULL; | |
318 | prz->old_log_size = 0; | |
319 | } | |
320 | ||
fce39793 AV |
321 | void persistent_ram_zap(struct persistent_ram_zone *prz) |
322 | { | |
323 | atomic_set(&prz->buffer->start, 0); | |
324 | atomic_set(&prz->buffer->size, 0); | |
325 | persistent_ram_update_header_ecc(prz); | |
326 | } | |
327 | ||
2b1321e4 | 328 | static void *persistent_ram_vmap(phys_addr_t start, size_t size) |
c672528a | 329 | { |
404a6043 CC |
330 | struct page **pages; |
331 | phys_addr_t page_start; | |
332 | unsigned int page_count; | |
333 | pgprot_t prot; | |
334 | unsigned int i; | |
2b1321e4 | 335 | void *vaddr; |
404a6043 CC |
336 | |
337 | page_start = start - offset_in_page(start); | |
338 | page_count = DIV_ROUND_UP(size + offset_in_page(start), PAGE_SIZE); | |
339 | ||
340 | prot = pgprot_noncached(PAGE_KERNEL); | |
341 | ||
342 | pages = kmalloc(sizeof(struct page *) * page_count, GFP_KERNEL); | |
343 | if (!pages) { | |
344 | pr_err("%s: Failed to allocate array for %u pages\n", __func__, | |
345 | page_count); | |
2b1321e4 | 346 | return NULL; |
404a6043 CC |
347 | } |
348 | ||
349 | for (i = 0; i < page_count; i++) { | |
350 | phys_addr_t addr = page_start + i * PAGE_SIZE; | |
351 | pages[i] = pfn_to_page(addr >> PAGE_SHIFT); | |
352 | } | |
2b1321e4 | 353 | vaddr = vmap(pages, page_count, VM_MAP, prot); |
404a6043 | 354 | kfree(pages); |
2b1321e4 AV |
355 | |
356 | return vaddr; | |
357 | } | |
358 | ||
24c3d2f3 AV |
359 | static void *persistent_ram_iomap(phys_addr_t start, size_t size) |
360 | { | |
361 | if (!request_mem_region(start, size, "persistent_ram")) { | |
362 | pr_err("request mem region (0x%llx@0x%llx) failed\n", | |
363 | (unsigned long long)size, (unsigned long long)start); | |
364 | return NULL; | |
365 | } | |
366 | ||
367 | return ioremap(start, size); | |
368 | } | |
369 | ||
2b1321e4 AV |
370 | static int persistent_ram_buffer_map(phys_addr_t start, phys_addr_t size, |
371 | struct persistent_ram_zone *prz) | |
372 | { | |
d3b48769 AV |
373 | prz->paddr = start; |
374 | prz->size = size; | |
375 | ||
24c3d2f3 AV |
376 | if (pfn_valid(start >> PAGE_SHIFT)) |
377 | prz->vaddr = persistent_ram_vmap(start, size); | |
378 | else | |
379 | prz->vaddr = persistent_ram_iomap(start, size); | |
380 | ||
404a6043 | 381 | if (!prz->vaddr) { |
2b1321e4 AV |
382 | pr_err("%s: Failed to map 0x%llx pages at 0x%llx\n", __func__, |
383 | (unsigned long long)size, (unsigned long long)start); | |
404a6043 CC |
384 | return -ENOMEM; |
385 | } | |
386 | ||
387 | prz->buffer = prz->vaddr + offset_in_page(start); | |
388 | prz->buffer_size = size - sizeof(struct persistent_ram_buffer); | |
389 | ||
390 | return 0; | |
391 | } | |
392 | ||
924d3711 | 393 | static int __devinit persistent_ram_post_init(struct persistent_ram_zone *prz, |
cbe7cbf5 | 394 | u32 sig, int ecc_size) |
404a6043 | 395 | { |
bb4206f2 | 396 | int ret; |
c672528a | 397 | |
5ca5d4e6 | 398 | ret = persistent_ram_init_ecc(prz, ecc_size); |
9cc05ad9 | 399 | if (ret) |
bb4206f2 | 400 | return ret; |
c672528a | 401 | |
cbe7cbf5 AV |
402 | sig ^= PERSISTENT_RAM_SIG; |
403 | ||
404 | if (prz->buffer->sig == sig) { | |
808d0387 CC |
405 | if (buffer_size(prz) > prz->buffer_size || |
406 | buffer_start(prz) > buffer_size(prz)) | |
407 | pr_info("persistent_ram: found existing invalid buffer," | |
f56d711b | 408 | " size %zu, start %zu\n", |
808d0387 | 409 | buffer_size(prz), buffer_start(prz)); |
c672528a | 410 | else { |
602b5be4 | 411 | pr_debug("persistent_ram: found existing buffer," |
f56d711b | 412 | " size %zu, start %zu\n", |
808d0387 | 413 | buffer_size(prz), buffer_start(prz)); |
c672528a | 414 | persistent_ram_save_old(prz); |
25b63da6 | 415 | return 0; |
c672528a CC |
416 | } |
417 | } else { | |
602b5be4 | 418 | pr_debug("persistent_ram: no valid data in buffer" |
808d0387 | 419 | " (sig = 0x%08x)\n", prz->buffer->sig); |
c672528a CC |
420 | } |
421 | ||
cbe7cbf5 | 422 | prz->buffer->sig = sig; |
fce39793 | 423 | persistent_ram_zap(prz); |
c672528a | 424 | |
bb4206f2 AV |
425 | return 0; |
426 | } | |
427 | ||
d3b48769 AV |
428 | void persistent_ram_free(struct persistent_ram_zone *prz) |
429 | { | |
beeb9432 AV |
430 | if (!prz) |
431 | return; | |
432 | ||
433 | if (prz->vaddr) { | |
434 | if (pfn_valid(prz->paddr >> PAGE_SHIFT)) { | |
435 | vunmap(prz->vaddr); | |
436 | } else { | |
437 | iounmap(prz->vaddr); | |
438 | release_mem_region(prz->paddr, prz->size); | |
439 | } | |
440 | prz->vaddr = NULL; | |
d3b48769 AV |
441 | } |
442 | persistent_ram_free_old(prz); | |
443 | kfree(prz); | |
444 | } | |
445 | ||
924d3711 | 446 | struct persistent_ram_zone * __devinit persistent_ram_new(phys_addr_t start, |
cbe7cbf5 | 447 | size_t size, u32 sig, |
5ca5d4e6 | 448 | int ecc_size) |
8cf5aff8 AV |
449 | { |
450 | struct persistent_ram_zone *prz; | |
451 | int ret = -ENOMEM; | |
452 | ||
453 | prz = kzalloc(sizeof(struct persistent_ram_zone), GFP_KERNEL); | |
454 | if (!prz) { | |
455 | pr_err("persistent_ram: failed to allocate persistent ram zone\n"); | |
456 | goto err; | |
457 | } | |
458 | ||
459 | ret = persistent_ram_buffer_map(start, size, prz); | |
460 | if (ret) | |
461 | goto err; | |
462 | ||
cbe7cbf5 | 463 | ret = persistent_ram_post_init(prz, sig, ecc_size); |
beeb9432 AV |
464 | if (ret) |
465 | goto err; | |
8cf5aff8 AV |
466 | |
467 | return prz; | |
468 | err: | |
beeb9432 | 469 | persistent_ram_free(prz); |
8cf5aff8 AV |
470 | return ERR_PTR(ret); |
471 | } |