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; | |
c31ad081 | 85 | uint16_t par[prz->ecc_info.ecc_size]; |
9cc05ad9 | 86 | |
c672528a CC |
87 | /* Initialize the parity buffer */ |
88 | memset(par, 0, sizeof(par)); | |
89 | encode_rs8(prz->rs_decoder, data, len, par, 0); | |
c31ad081 | 90 | for (i = 0; i < prz->ecc_info.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; | |
c31ad081 | 98 | uint16_t par[prz->ecc_info.ecc_size]; |
9cc05ad9 | 99 | |
c31ad081 | 100 | for (i = 0; i < prz->ecc_info.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; | |
c31ad081 AH |
113 | int ecc_block_size = prz->ecc_info.block_size; |
114 | int ecc_size = prz->ecc_info.ecc_size; | |
115 | int size = ecc_block_size; | |
9cc05ad9 | 116 | |
c31ad081 | 117 | if (!ecc_size) |
9cc05ad9 CC |
118 | return; |
119 | ||
808d0387 | 120 | block = buffer->data + (start & ~(ecc_block_size - 1)); |
c31ad081 | 121 | par = prz->par_buffer + (start / ecc_block_size) * ecc_size; |
808d0387 | 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 | ||
c31ad081 | 136 | if (!prz->ecc_info.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 | ||
c31ad081 | 149 | if (!prz->ecc_info.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; |
c31ad081 | 156 | int size = prz->ecc_info.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 | } | |
c31ad081 AH |
169 | block += prz->ecc_info.block_size; |
170 | par += prz->ecc_info.ecc_size; | |
9cc05ad9 CC |
171 | } |
172 | } | |
173 | ||
5ca5d4e6 | 174 | static int persistent_ram_init_ecc(struct persistent_ram_zone *prz, |
c31ad081 | 175 | struct persistent_ram_ecc_info *ecc_info) |
9cc05ad9 CC |
176 | { |
177 | int numerr; | |
178 | struct persistent_ram_buffer *buffer = prz->buffer; | |
179 | int ecc_blocks; | |
1e6a9e56 | 180 | size_t ecc_total; |
9cc05ad9 | 181 | |
c31ad081 | 182 | if (!ecc_info || !ecc_info->ecc_size) |
9cc05ad9 CC |
183 | return 0; |
184 | ||
c31ad081 AH |
185 | prz->ecc_info.block_size = ecc_info->block_size ?: 128; |
186 | prz->ecc_info.ecc_size = ecc_info->ecc_size ?: 16; | |
187 | prz->ecc_info.symsize = ecc_info->symsize ?: 8; | |
188 | prz->ecc_info.poly = ecc_info->poly ?: 0x11d; | |
9cc05ad9 | 189 | |
c31ad081 AH |
190 | ecc_blocks = DIV_ROUND_UP(prz->buffer_size - prz->ecc_info.ecc_size, |
191 | prz->ecc_info.block_size + | |
192 | prz->ecc_info.ecc_size); | |
193 | ecc_total = (ecc_blocks + 1) * prz->ecc_info.ecc_size; | |
1e6a9e56 AV |
194 | if (ecc_total >= prz->buffer_size) { |
195 | pr_err("%s: invalid ecc_size %u (total %zu, buffer size %zu)\n", | |
c31ad081 AH |
196 | __func__, prz->ecc_info.ecc_size, |
197 | ecc_total, prz->buffer_size); | |
9cc05ad9 CC |
198 | return -EINVAL; |
199 | } | |
200 | ||
1e6a9e56 | 201 | prz->buffer_size -= ecc_total; |
9cc05ad9 | 202 | prz->par_buffer = buffer->data + prz->buffer_size; |
c31ad081 AH |
203 | prz->par_header = prz->par_buffer + |
204 | ecc_blocks * prz->ecc_info.ecc_size; | |
9cc05ad9 CC |
205 | |
206 | /* | |
207 | * first consecutive root is 0 | |
208 | * primitive element to generate roots = 1 | |
209 | */ | |
c31ad081 AH |
210 | prz->rs_decoder = init_rs(prz->ecc_info.symsize, prz->ecc_info.poly, |
211 | 0, 1, prz->ecc_info.ecc_size); | |
9cc05ad9 CC |
212 | if (prz->rs_decoder == NULL) { |
213 | pr_info("persistent_ram: init_rs failed\n"); | |
214 | return -EINVAL; | |
c672528a | 215 | } |
9cc05ad9 CC |
216 | |
217 | prz->corrected_bytes = 0; | |
218 | prz->bad_blocks = 0; | |
219 | ||
220 | numerr = persistent_ram_decode_rs8(prz, buffer, sizeof(*buffer), | |
221 | prz->par_header); | |
222 | if (numerr > 0) { | |
223 | pr_info("persistent_ram: error in header, %d\n", numerr); | |
224 | prz->corrected_bytes += numerr; | |
225 | } else if (numerr < 0) { | |
226 | pr_info("persistent_ram: uncorrectable error in header\n"); | |
227 | prz->bad_blocks++; | |
228 | } | |
229 | ||
230 | return 0; | |
231 | } | |
232 | ||
233 | ssize_t persistent_ram_ecc_string(struct persistent_ram_zone *prz, | |
234 | char *str, size_t len) | |
235 | { | |
236 | ssize_t ret; | |
237 | ||
bd08ec33 AH |
238 | if (!prz->ecc_info.ecc_size) |
239 | return 0; | |
240 | ||
9cc05ad9 CC |
241 | if (prz->corrected_bytes || prz->bad_blocks) |
242 | ret = snprintf(str, len, "" | |
243 | "\n%d Corrected bytes, %d unrecoverable blocks\n", | |
244 | prz->corrected_bytes, prz->bad_blocks); | |
245 | else | |
246 | ret = snprintf(str, len, "\nNo errors detected\n"); | |
247 | ||
248 | return ret; | |
249 | } | |
250 | ||
a15d0b36 | 251 | static void notrace persistent_ram_update(struct persistent_ram_zone *prz, |
808d0387 | 252 | const void *s, unsigned int start, unsigned int count) |
9cc05ad9 CC |
253 | { |
254 | struct persistent_ram_buffer *buffer = prz->buffer; | |
808d0387 CC |
255 | memcpy(buffer->data + start, s, count); |
256 | persistent_ram_update_ecc(prz, start, count); | |
9cc05ad9 CC |
257 | } |
258 | ||
201e4aca | 259 | void persistent_ram_save_old(struct persistent_ram_zone *prz) |
9cc05ad9 CC |
260 | { |
261 | struct persistent_ram_buffer *buffer = prz->buffer; | |
808d0387 CC |
262 | size_t size = buffer_size(prz); |
263 | size_t start = buffer_start(prz); | |
9cc05ad9 | 264 | |
201e4aca AV |
265 | if (!size) |
266 | return; | |
c672528a | 267 | |
201e4aca AV |
268 | if (!prz->old_log) { |
269 | persistent_ram_ecc_old(prz); | |
270 | prz->old_log = kmalloc(size, GFP_KERNEL); | |
271 | } | |
272 | if (!prz->old_log) { | |
c672528a CC |
273 | pr_err("persistent_ram: failed to allocate buffer\n"); |
274 | return; | |
275 | } | |
276 | ||
808d0387 CC |
277 | prz->old_log_size = size; |
278 | memcpy(prz->old_log, &buffer->data[start], size - start); | |
279 | memcpy(prz->old_log + size - start, &buffer->data[0], start); | |
c672528a CC |
280 | } |
281 | ||
a15d0b36 | 282 | int notrace persistent_ram_write(struct persistent_ram_zone *prz, |
c672528a CC |
283 | const void *s, unsigned int count) |
284 | { | |
285 | int rem; | |
286 | int c = count; | |
808d0387 | 287 | size_t start; |
c672528a | 288 | |
808d0387 | 289 | if (unlikely(c > prz->buffer_size)) { |
c672528a CC |
290 | s += c - prz->buffer_size; |
291 | c = prz->buffer_size; | |
292 | } | |
808d0387 | 293 | |
484dd30e | 294 | buffer_size_add(prz, c); |
808d0387 CC |
295 | |
296 | start = buffer_start_add(prz, c); | |
297 | ||
298 | rem = prz->buffer_size - start; | |
299 | if (unlikely(rem < c)) { | |
300 | persistent_ram_update(prz, s, start, rem); | |
c672528a CC |
301 | s += rem; |
302 | c -= rem; | |
808d0387 | 303 | start = 0; |
c672528a | 304 | } |
808d0387 | 305 | persistent_ram_update(prz, s, start, c); |
c672528a | 306 | |
9cc05ad9 | 307 | persistent_ram_update_header_ecc(prz); |
c672528a CC |
308 | |
309 | return count; | |
310 | } | |
311 | ||
c672528a CC |
312 | size_t persistent_ram_old_size(struct persistent_ram_zone *prz) |
313 | { | |
314 | return prz->old_log_size; | |
315 | } | |
316 | ||
317 | void *persistent_ram_old(struct persistent_ram_zone *prz) | |
318 | { | |
319 | return prz->old_log; | |
320 | } | |
321 | ||
322 | void persistent_ram_free_old(struct persistent_ram_zone *prz) | |
323 | { | |
324 | kfree(prz->old_log); | |
325 | prz->old_log = NULL; | |
326 | prz->old_log_size = 0; | |
327 | } | |
328 | ||
fce39793 AV |
329 | void persistent_ram_zap(struct persistent_ram_zone *prz) |
330 | { | |
331 | atomic_set(&prz->buffer->start, 0); | |
332 | atomic_set(&prz->buffer->size, 0); | |
333 | persistent_ram_update_header_ecc(prz); | |
334 | } | |
335 | ||
2b1321e4 | 336 | static void *persistent_ram_vmap(phys_addr_t start, size_t size) |
c672528a | 337 | { |
404a6043 CC |
338 | struct page **pages; |
339 | phys_addr_t page_start; | |
340 | unsigned int page_count; | |
341 | pgprot_t prot; | |
342 | unsigned int i; | |
2b1321e4 | 343 | void *vaddr; |
404a6043 CC |
344 | |
345 | page_start = start - offset_in_page(start); | |
346 | page_count = DIV_ROUND_UP(size + offset_in_page(start), PAGE_SIZE); | |
347 | ||
348 | prot = pgprot_noncached(PAGE_KERNEL); | |
349 | ||
350 | pages = kmalloc(sizeof(struct page *) * page_count, GFP_KERNEL); | |
351 | if (!pages) { | |
352 | pr_err("%s: Failed to allocate array for %u pages\n", __func__, | |
353 | page_count); | |
2b1321e4 | 354 | return NULL; |
404a6043 CC |
355 | } |
356 | ||
357 | for (i = 0; i < page_count; i++) { | |
358 | phys_addr_t addr = page_start + i * PAGE_SIZE; | |
359 | pages[i] = pfn_to_page(addr >> PAGE_SHIFT); | |
360 | } | |
2b1321e4 | 361 | vaddr = vmap(pages, page_count, VM_MAP, prot); |
404a6043 | 362 | kfree(pages); |
2b1321e4 AV |
363 | |
364 | return vaddr; | |
365 | } | |
366 | ||
24c3d2f3 AV |
367 | static void *persistent_ram_iomap(phys_addr_t start, size_t size) |
368 | { | |
369 | if (!request_mem_region(start, size, "persistent_ram")) { | |
370 | pr_err("request mem region (0x%llx@0x%llx) failed\n", | |
371 | (unsigned long long)size, (unsigned long long)start); | |
372 | return NULL; | |
373 | } | |
374 | ||
375 | return ioremap(start, size); | |
376 | } | |
377 | ||
2b1321e4 AV |
378 | static int persistent_ram_buffer_map(phys_addr_t start, phys_addr_t size, |
379 | struct persistent_ram_zone *prz) | |
380 | { | |
d3b48769 AV |
381 | prz->paddr = start; |
382 | prz->size = size; | |
383 | ||
24c3d2f3 AV |
384 | if (pfn_valid(start >> PAGE_SHIFT)) |
385 | prz->vaddr = persistent_ram_vmap(start, size); | |
386 | else | |
387 | prz->vaddr = persistent_ram_iomap(start, size); | |
388 | ||
404a6043 | 389 | if (!prz->vaddr) { |
2b1321e4 AV |
390 | pr_err("%s: Failed to map 0x%llx pages at 0x%llx\n", __func__, |
391 | (unsigned long long)size, (unsigned long long)start); | |
404a6043 CC |
392 | return -ENOMEM; |
393 | } | |
394 | ||
395 | prz->buffer = prz->vaddr + offset_in_page(start); | |
396 | prz->buffer_size = size - sizeof(struct persistent_ram_buffer); | |
397 | ||
398 | return 0; | |
399 | } | |
400 | ||
f568f6ca | 401 | static int persistent_ram_post_init(struct persistent_ram_zone *prz, u32 sig, |
c31ad081 | 402 | struct persistent_ram_ecc_info *ecc_info) |
404a6043 | 403 | { |
bb4206f2 | 404 | int ret; |
c672528a | 405 | |
c31ad081 | 406 | ret = persistent_ram_init_ecc(prz, ecc_info); |
9cc05ad9 | 407 | if (ret) |
bb4206f2 | 408 | return ret; |
c672528a | 409 | |
cbe7cbf5 AV |
410 | sig ^= PERSISTENT_RAM_SIG; |
411 | ||
412 | if (prz->buffer->sig == sig) { | |
808d0387 CC |
413 | if (buffer_size(prz) > prz->buffer_size || |
414 | buffer_start(prz) > buffer_size(prz)) | |
415 | pr_info("persistent_ram: found existing invalid buffer," | |
f56d711b | 416 | " size %zu, start %zu\n", |
808d0387 | 417 | buffer_size(prz), buffer_start(prz)); |
c672528a | 418 | else { |
602b5be4 | 419 | pr_debug("persistent_ram: found existing buffer," |
f56d711b | 420 | " size %zu, start %zu\n", |
808d0387 | 421 | buffer_size(prz), buffer_start(prz)); |
c672528a | 422 | persistent_ram_save_old(prz); |
25b63da6 | 423 | return 0; |
c672528a CC |
424 | } |
425 | } else { | |
602b5be4 | 426 | pr_debug("persistent_ram: no valid data in buffer" |
808d0387 | 427 | " (sig = 0x%08x)\n", prz->buffer->sig); |
c672528a CC |
428 | } |
429 | ||
cbe7cbf5 | 430 | prz->buffer->sig = sig; |
fce39793 | 431 | persistent_ram_zap(prz); |
c672528a | 432 | |
bb4206f2 AV |
433 | return 0; |
434 | } | |
435 | ||
d3b48769 AV |
436 | void persistent_ram_free(struct persistent_ram_zone *prz) |
437 | { | |
beeb9432 AV |
438 | if (!prz) |
439 | return; | |
440 | ||
441 | if (prz->vaddr) { | |
442 | if (pfn_valid(prz->paddr >> PAGE_SHIFT)) { | |
443 | vunmap(prz->vaddr); | |
444 | } else { | |
445 | iounmap(prz->vaddr); | |
446 | release_mem_region(prz->paddr, prz->size); | |
447 | } | |
448 | prz->vaddr = NULL; | |
d3b48769 AV |
449 | } |
450 | persistent_ram_free_old(prz); | |
451 | kfree(prz); | |
452 | } | |
453 | ||
f568f6ca | 454 | struct persistent_ram_zone *persistent_ram_new(phys_addr_t start, size_t size, |
c31ad081 | 455 | u32 sig, struct persistent_ram_ecc_info *ecc_info) |
8cf5aff8 AV |
456 | { |
457 | struct persistent_ram_zone *prz; | |
458 | int ret = -ENOMEM; | |
459 | ||
460 | prz = kzalloc(sizeof(struct persistent_ram_zone), GFP_KERNEL); | |
461 | if (!prz) { | |
462 | pr_err("persistent_ram: failed to allocate persistent ram zone\n"); | |
463 | goto err; | |
464 | } | |
465 | ||
466 | ret = persistent_ram_buffer_map(start, size, prz); | |
467 | if (ret) | |
468 | goto err; | |
469 | ||
c31ad081 | 470 | ret = persistent_ram_post_init(prz, sig, ecc_info); |
beeb9432 AV |
471 | if (ret) |
472 | goto err; | |
8cf5aff8 AV |
473 | |
474 | return prz; | |
475 | err: | |
beeb9432 | 476 | persistent_ram_free(prz); |
8cf5aff8 AV |
477 | return ERR_PTR(ret); |
478 | } |