2 * Copyright (C) 2012 Google, Inc.
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.
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.
15 #include <linux/device.h>
16 #include <linux/err.h>
17 #include <linux/errno.h>
18 #include <linux/kernel.h>
19 #include <linux/init.h>
21 #include <linux/list.h>
22 #include <linux/memblock.h>
23 #include <linux/rslib.h>
24 #include <linux/slab.h>
25 #include <linux/vmalloc.h>
26 #include <linux/pstore_ram.h>
29 struct persistent_ram_buffer {
36 #define PERSISTENT_RAM_SIG (0x43474244) /* DBGC */
38 static inline size_t buffer_size(struct persistent_ram_zone *prz)
40 return atomic_read(&prz->buffer->size);
43 static inline size_t buffer_start(struct persistent_ram_zone *prz)
45 return atomic_read(&prz->buffer->start);
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)
55 old = atomic_read(&prz->buffer->start);
57 while (unlikely(new > prz->buffer_size))
58 new -= prz->buffer_size;
59 } while (atomic_cmpxchg(&prz->buffer->start, old, new) != old);
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)
70 if (atomic_read(&prz->buffer->size) == prz->buffer_size)
74 old = atomic_read(&prz->buffer->size);
76 if (new > prz->buffer_size)
77 new = prz->buffer_size;
78 } while (atomic_cmpxchg(&prz->buffer->size, old, new) != old);
81 static void notrace persistent_ram_encode_rs8(struct persistent_ram_zone *prz,
82 uint8_t *data, size_t len, uint8_t *ecc)
85 uint16_t par[prz->ecc_info.ecc_size];
87 /* Initialize the parity buffer */
88 memset(par, 0, sizeof(par));
89 encode_rs8(prz->rs_decoder, data, len, par, 0);
90 for (i = 0; i < prz->ecc_info.ecc_size; i++)
94 static int persistent_ram_decode_rs8(struct persistent_ram_zone *prz,
95 void *data, size_t len, uint8_t *ecc)
98 uint16_t par[prz->ecc_info.ecc_size];
100 for (i = 0; i < prz->ecc_info.ecc_size; i++)
102 return decode_rs8(prz->rs_decoder, data, par, len,
103 NULL, 0, NULL, 0, NULL);
106 static void notrace persistent_ram_update_ecc(struct persistent_ram_zone *prz,
107 unsigned int start, unsigned int count)
109 struct persistent_ram_buffer *buffer = prz->buffer;
110 uint8_t *buffer_end = buffer->data + prz->buffer_size;
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;
120 block = buffer->data + (start & ~(ecc_block_size - 1));
121 par = prz->par_buffer + (start / ecc_block_size) * ecc_size;
124 if (block + ecc_block_size > buffer_end)
125 size = buffer_end - block;
126 persistent_ram_encode_rs8(prz, block, size, par);
127 block += ecc_block_size;
129 } while (block < buffer->data + start + count);
132 static void persistent_ram_update_header_ecc(struct persistent_ram_zone *prz)
134 struct persistent_ram_buffer *buffer = prz->buffer;
136 if (!prz->ecc_info.ecc_size)
139 persistent_ram_encode_rs8(prz, (uint8_t *)buffer, sizeof(*buffer),
143 static void persistent_ram_ecc_old(struct persistent_ram_zone *prz)
145 struct persistent_ram_buffer *buffer = prz->buffer;
149 if (!prz->ecc_info.ecc_size)
152 block = buffer->data;
153 par = prz->par_buffer;
154 while (block < buffer->data + buffer_size(prz)) {
156 int size = prz->ecc_info.block_size;
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);
161 pr_devel("persistent_ram: error in block %p, %d\n",
163 prz->corrected_bytes += numerr;
164 } else if (numerr < 0) {
165 pr_devel("persistent_ram: uncorrectable error in block %p\n",
169 block += prz->ecc_info.block_size;
170 par += prz->ecc_info.ecc_size;
174 static int persistent_ram_init_ecc(struct persistent_ram_zone *prz,
175 struct persistent_ram_ecc_info *ecc_info)
178 struct persistent_ram_buffer *buffer = prz->buffer;
182 if (!ecc_info || !ecc_info->ecc_size)
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;
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;
194 if (ecc_total >= prz->buffer_size) {
195 pr_err("%s: invalid ecc_size %u (total %zu, buffer size %zu)\n",
196 __func__, prz->ecc_info.ecc_size,
197 ecc_total, prz->buffer_size);
201 prz->buffer_size -= ecc_total;
202 prz->par_buffer = buffer->data + prz->buffer_size;
203 prz->par_header = prz->par_buffer +
204 ecc_blocks * prz->ecc_info.ecc_size;
207 * first consecutive root is 0
208 * primitive element to generate roots = 1
210 prz->rs_decoder = init_rs(prz->ecc_info.symsize, prz->ecc_info.poly,
211 0, 1, prz->ecc_info.ecc_size);
212 if (prz->rs_decoder == NULL) {
213 pr_info("persistent_ram: init_rs failed\n");
217 prz->corrected_bytes = 0;
220 numerr = persistent_ram_decode_rs8(prz, buffer, sizeof(*buffer),
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");
233 ssize_t persistent_ram_ecc_string(struct persistent_ram_zone *prz,
234 char *str, size_t len)
238 if (!prz->ecc_info.ecc_size)
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);
246 ret = snprintf(str, len, "\nNo errors detected\n");
251 static void notrace persistent_ram_update(struct persistent_ram_zone *prz,
252 const void *s, unsigned int start, unsigned int count)
254 struct persistent_ram_buffer *buffer = prz->buffer;
255 memcpy(buffer->data + start, s, count);
256 persistent_ram_update_ecc(prz, start, count);
259 void persistent_ram_save_old(struct persistent_ram_zone *prz)
261 struct persistent_ram_buffer *buffer = prz->buffer;
262 size_t size = buffer_size(prz);
263 size_t start = buffer_start(prz);
269 persistent_ram_ecc_old(prz);
270 prz->old_log = kmalloc(size, GFP_KERNEL);
273 pr_err("persistent_ram: failed to allocate buffer\n");
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);
282 int notrace persistent_ram_write(struct persistent_ram_zone *prz,
283 const void *s, unsigned int count)
289 if (unlikely(c > prz->buffer_size)) {
290 s += c - prz->buffer_size;
291 c = prz->buffer_size;
294 buffer_size_add(prz, c);
296 start = buffer_start_add(prz, c);
298 rem = prz->buffer_size - start;
299 if (unlikely(rem < c)) {
300 persistent_ram_update(prz, s, start, rem);
305 persistent_ram_update(prz, s, start, c);
307 persistent_ram_update_header_ecc(prz);
312 size_t persistent_ram_old_size(struct persistent_ram_zone *prz)
314 return prz->old_log_size;
317 void *persistent_ram_old(struct persistent_ram_zone *prz)
322 void persistent_ram_free_old(struct persistent_ram_zone *prz)
326 prz->old_log_size = 0;
329 void persistent_ram_zap(struct persistent_ram_zone *prz)
331 atomic_set(&prz->buffer->start, 0);
332 atomic_set(&prz->buffer->size, 0);
333 persistent_ram_update_header_ecc(prz);
336 static void *persistent_ram_vmap(phys_addr_t start, size_t size)
339 phys_addr_t page_start;
340 unsigned int page_count;
345 page_start = start - offset_in_page(start);
346 page_count = DIV_ROUND_UP(size + offset_in_page(start), PAGE_SIZE);
348 prot = pgprot_noncached(PAGE_KERNEL);
350 pages = kmalloc(sizeof(struct page *) * page_count, GFP_KERNEL);
352 pr_err("%s: Failed to allocate array for %u pages\n", __func__,
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);
361 vaddr = vmap(pages, page_count, VM_MAP, prot);
367 static void *persistent_ram_iomap(phys_addr_t start, size_t size)
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);
375 return ioremap(start, size);
378 static int persistent_ram_buffer_map(phys_addr_t start, phys_addr_t size,
379 struct persistent_ram_zone *prz)
384 if (pfn_valid(start >> PAGE_SHIFT))
385 prz->vaddr = persistent_ram_vmap(start, size);
387 prz->vaddr = persistent_ram_iomap(start, size);
390 pr_err("%s: Failed to map 0x%llx pages at 0x%llx\n", __func__,
391 (unsigned long long)size, (unsigned long long)start);
395 prz->buffer = prz->vaddr + offset_in_page(start);
396 prz->buffer_size = size - sizeof(struct persistent_ram_buffer);
401 static int persistent_ram_post_init(struct persistent_ram_zone *prz, u32 sig,
402 struct persistent_ram_ecc_info *ecc_info)
406 ret = persistent_ram_init_ecc(prz, ecc_info);
410 sig ^= PERSISTENT_RAM_SIG;
412 if (prz->buffer->sig == sig) {
413 if (buffer_size(prz) > prz->buffer_size ||
414 buffer_start(prz) > buffer_size(prz))
415 pr_info("persistent_ram: found existing invalid buffer,"
416 " size %zu, start %zu\n",
417 buffer_size(prz), buffer_start(prz));
419 pr_debug("persistent_ram: found existing buffer,"
420 " size %zu, start %zu\n",
421 buffer_size(prz), buffer_start(prz));
422 persistent_ram_save_old(prz);
426 pr_debug("persistent_ram: no valid data in buffer"
427 " (sig = 0x%08x)\n", prz->buffer->sig);
430 prz->buffer->sig = sig;
431 persistent_ram_zap(prz);
436 void persistent_ram_free(struct persistent_ram_zone *prz)
442 if (pfn_valid(prz->paddr >> PAGE_SHIFT)) {
446 release_mem_region(prz->paddr, prz->size);
450 persistent_ram_free_old(prz);
454 struct persistent_ram_zone *persistent_ram_new(phys_addr_t start, size_t size,
455 u32 sig, struct persistent_ram_ecc_info *ecc_info)
457 struct persistent_ram_zone *prz;
460 prz = kzalloc(sizeof(struct persistent_ram_zone), GFP_KERNEL);
462 pr_err("persistent_ram: failed to allocate persistent ram zone\n");
466 ret = persistent_ram_buffer_map(start, size, prz);
470 ret = persistent_ram_post_init(prz, sig, ecc_info);
476 persistent_ram_free(prz);