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 "persistent_ram.h"
28 struct persistent_ram_buffer {
35 #define PERSISTENT_RAM_SIG (0x43474244) /* DBGC */
37 static __initdata LIST_HEAD(persistent_ram_list);
39 static inline size_t buffer_size(struct persistent_ram_zone *prz)
41 return atomic_read(&prz->buffer->size);
44 static inline size_t buffer_start(struct persistent_ram_zone *prz)
46 return atomic_read(&prz->buffer->start);
49 /* increase and wrap the start pointer, returning the old value */
50 static inline size_t buffer_start_add(struct persistent_ram_zone *prz, size_t a)
56 old = atomic_read(&prz->buffer->start);
58 while (unlikely(new > prz->buffer_size))
59 new -= prz->buffer_size;
60 } while (atomic_cmpxchg(&prz->buffer->start, old, new) != old);
65 /* increase the size counter until it hits the max size */
66 static inline void buffer_size_add(struct persistent_ram_zone *prz, size_t a)
71 if (atomic_read(&prz->buffer->size) == prz->buffer_size)
75 old = atomic_read(&prz->buffer->size);
77 if (new > prz->buffer_size)
78 new = prz->buffer_size;
79 } while (atomic_cmpxchg(&prz->buffer->size, old, new) != old);
82 static void notrace persistent_ram_encode_rs8(struct persistent_ram_zone *prz,
83 uint8_t *data, size_t len, uint8_t *ecc)
86 uint16_t par[prz->ecc_size];
88 /* Initialize the parity buffer */
89 memset(par, 0, sizeof(par));
90 encode_rs8(prz->rs_decoder, data, len, par, 0);
91 for (i = 0; i < prz->ecc_size; i++)
95 static int persistent_ram_decode_rs8(struct persistent_ram_zone *prz,
96 void *data, size_t len, uint8_t *ecc)
99 uint16_t par[prz->ecc_size];
101 for (i = 0; i < prz->ecc_size; i++)
103 return decode_rs8(prz->rs_decoder, data, par, len,
104 NULL, 0, NULL, 0, NULL);
107 static void notrace persistent_ram_update_ecc(struct persistent_ram_zone *prz,
108 unsigned int start, unsigned int count)
110 struct persistent_ram_buffer *buffer = prz->buffer;
111 uint8_t *buffer_end = buffer->data + prz->buffer_size;
114 int ecc_block_size = prz->ecc_block_size;
115 int ecc_size = prz->ecc_size;
116 int size = prz->ecc_block_size;
121 block = buffer->data + (start & ~(ecc_block_size - 1));
122 par = prz->par_buffer + (start / ecc_block_size) * prz->ecc_size;
125 if (block + ecc_block_size > buffer_end)
126 size = buffer_end - block;
127 persistent_ram_encode_rs8(prz, block, size, par);
128 block += ecc_block_size;
130 } while (block < buffer->data + start + count);
133 static void persistent_ram_update_header_ecc(struct persistent_ram_zone *prz)
135 struct persistent_ram_buffer *buffer = prz->buffer;
140 persistent_ram_encode_rs8(prz, (uint8_t *)buffer, sizeof(*buffer),
144 static void persistent_ram_ecc_old(struct persistent_ram_zone *prz)
146 struct persistent_ram_buffer *buffer = prz->buffer;
153 block = buffer->data;
154 par = prz->par_buffer;
155 while (block < buffer->data + buffer_size(prz)) {
157 int size = prz->ecc_block_size;
158 if (block + size > buffer->data + prz->buffer_size)
159 size = buffer->data + prz->buffer_size - block;
160 numerr = persistent_ram_decode_rs8(prz, block, size, par);
162 pr_devel("persistent_ram: error in block %p, %d\n",
164 prz->corrected_bytes += numerr;
165 } else if (numerr < 0) {
166 pr_devel("persistent_ram: uncorrectable error in block %p\n",
170 block += prz->ecc_block_size;
171 par += prz->ecc_size;
175 static int persistent_ram_init_ecc(struct persistent_ram_zone *prz,
179 struct persistent_ram_buffer *buffer = prz->buffer;
185 prz->ecc_block_size = 128;
187 prz->ecc_symsize = 8;
188 prz->ecc_poly = 0x11d;
190 ecc_blocks = DIV_ROUND_UP(prz->buffer_size, prz->ecc_block_size);
191 prz->buffer_size -= (ecc_blocks + 1) * prz->ecc_size;
193 if (prz->buffer_size > buffer_size) {
194 pr_err("persistent_ram: invalid size %zu, non-ecc datasize %zu\n",
195 buffer_size, prz->buffer_size);
199 prz->par_buffer = buffer->data + prz->buffer_size;
200 prz->par_header = prz->par_buffer + ecc_blocks * prz->ecc_size;
203 * first consecutive root is 0
204 * primitive element to generate roots = 1
206 prz->rs_decoder = init_rs(prz->ecc_symsize, prz->ecc_poly, 0, 1,
208 if (prz->rs_decoder == NULL) {
209 pr_info("persistent_ram: init_rs failed\n");
213 prz->corrected_bytes = 0;
216 numerr = persistent_ram_decode_rs8(prz, buffer, sizeof(*buffer),
219 pr_info("persistent_ram: error in header, %d\n", numerr);
220 prz->corrected_bytes += numerr;
221 } else if (numerr < 0) {
222 pr_info("persistent_ram: uncorrectable error in header\n");
229 ssize_t persistent_ram_ecc_string(struct persistent_ram_zone *prz,
230 char *str, size_t len)
234 if (prz->corrected_bytes || prz->bad_blocks)
235 ret = snprintf(str, len, ""
236 "\n%d Corrected bytes, %d unrecoverable blocks\n",
237 prz->corrected_bytes, prz->bad_blocks);
239 ret = snprintf(str, len, "\nNo errors detected\n");
244 static void notrace persistent_ram_update(struct persistent_ram_zone *prz,
245 const void *s, unsigned int start, unsigned int count)
247 struct persistent_ram_buffer *buffer = prz->buffer;
248 memcpy(buffer->data + start, s, count);
249 persistent_ram_update_ecc(prz, start, count);
253 persistent_ram_save_old(struct persistent_ram_zone *prz)
255 struct persistent_ram_buffer *buffer = prz->buffer;
256 size_t size = buffer_size(prz);
257 size_t start = buffer_start(prz);
260 persistent_ram_ecc_old(prz);
262 dest = kmalloc(size, GFP_KERNEL);
264 pr_err("persistent_ram: failed to allocate buffer\n");
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);
274 int notrace persistent_ram_write(struct persistent_ram_zone *prz,
275 const void *s, unsigned int count)
281 if (unlikely(c > prz->buffer_size)) {
282 s += c - prz->buffer_size;
283 c = prz->buffer_size;
286 buffer_size_add(prz, c);
288 start = buffer_start_add(prz, c);
290 rem = prz->buffer_size - start;
291 if (unlikely(rem < c)) {
292 persistent_ram_update(prz, s, start, rem);
297 persistent_ram_update(prz, s, start, c);
299 persistent_ram_update_header_ecc(prz);
304 size_t persistent_ram_old_size(struct persistent_ram_zone *prz)
306 return prz->old_log_size;
309 void *persistent_ram_old(struct persistent_ram_zone *prz)
314 void persistent_ram_free_old(struct persistent_ram_zone *prz)
318 prz->old_log_size = 0;
321 static void *persistent_ram_vmap(phys_addr_t start, size_t size)
324 phys_addr_t page_start;
325 unsigned int page_count;
330 page_start = start - offset_in_page(start);
331 page_count = DIV_ROUND_UP(size + offset_in_page(start), PAGE_SIZE);
333 prot = pgprot_noncached(PAGE_KERNEL);
335 pages = kmalloc(sizeof(struct page *) * page_count, GFP_KERNEL);
337 pr_err("%s: Failed to allocate array for %u pages\n", __func__,
342 for (i = 0; i < page_count; i++) {
343 phys_addr_t addr = page_start + i * PAGE_SIZE;
344 pages[i] = pfn_to_page(addr >> PAGE_SHIFT);
346 vaddr = vmap(pages, page_count, VM_MAP, prot);
352 static int persistent_ram_buffer_map(phys_addr_t start, phys_addr_t size,
353 struct persistent_ram_zone *prz)
355 prz->vaddr = persistent_ram_vmap(start, size);
357 pr_err("%s: Failed to map 0x%llx pages at 0x%llx\n", __func__,
358 (unsigned long long)size, (unsigned long long)start);
362 prz->buffer = prz->vaddr + offset_in_page(start);
363 prz->buffer_size = size - sizeof(struct persistent_ram_buffer);
368 static int __init persistent_ram_buffer_init(const char *name,
369 struct persistent_ram_zone *prz)
372 struct persistent_ram *ram;
373 struct persistent_ram_descriptor *desc;
376 list_for_each_entry(ram, &persistent_ram_list, node) {
378 for (i = 0; i < ram->num_descs; i++) {
379 desc = &ram->descs[i];
380 if (!strcmp(desc->name, name))
381 return persistent_ram_buffer_map(start,
390 static int __init persistent_ram_post_init(struct persistent_ram_zone *prz, bool ecc)
396 ret = persistent_ram_init_ecc(prz, prz->buffer_size);
400 if (prz->buffer->sig == PERSISTENT_RAM_SIG) {
401 if (buffer_size(prz) > prz->buffer_size ||
402 buffer_start(prz) > buffer_size(prz))
403 pr_info("persistent_ram: found existing invalid buffer,"
404 " size %zu, start %zu\n",
405 buffer_size(prz), buffer_start(prz));
407 pr_info("persistent_ram: found existing buffer,"
408 " size %zu, start %zu\n",
409 buffer_size(prz), buffer_start(prz));
410 persistent_ram_save_old(prz);
413 pr_info("persistent_ram: no valid data in buffer"
414 " (sig = 0x%08x)\n", prz->buffer->sig);
417 prz->buffer->sig = PERSISTENT_RAM_SIG;
418 atomic_set(&prz->buffer->start, 0);
419 atomic_set(&prz->buffer->size, 0);
424 struct persistent_ram_zone * __init persistent_ram_new(phys_addr_t start,
428 struct persistent_ram_zone *prz;
431 prz = kzalloc(sizeof(struct persistent_ram_zone), GFP_KERNEL);
433 pr_err("persistent_ram: failed to allocate persistent ram zone\n");
437 ret = persistent_ram_buffer_map(start, size, prz);
441 persistent_ram_post_init(prz, ecc);
442 persistent_ram_update_header_ecc(prz);
451 struct persistent_ram_zone *__persistent_ram_init(struct device *dev, bool ecc)
453 struct persistent_ram_zone *prz;
456 prz = kzalloc(sizeof(struct persistent_ram_zone), GFP_KERNEL);
458 pr_err("persistent_ram: failed to allocate persistent ram zone\n");
462 ret = persistent_ram_buffer_init(dev_name(dev), prz);
464 pr_err("persistent_ram: failed to initialize buffer\n");
468 persistent_ram_post_init(prz, ecc);
476 struct persistent_ram_zone * __init
477 persistent_ram_init_ringbuffer(struct device *dev, bool ecc)
479 return __persistent_ram_init(dev, ecc);
482 int __init persistent_ram_early_init(struct persistent_ram *ram)
486 ret = memblock_reserve(ram->start, ram->size);
488 pr_err("Failed to reserve persistent memory from %08lx-%08lx\n",
489 (long)ram->start, (long)(ram->start + ram->size - 1));
493 list_add_tail(&ram->node, &persistent_ram_list);
495 pr_info("Initialized persistent memory from %08lx-%08lx\n",
496 (long)ram->start, (long)(ram->start + ram->size - 1));