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 void notrace persistent_ram_encode_rs8(struct persistent_ram_zone *prz,
40 uint8_t *data, size_t len, uint8_t *ecc)
43 uint16_t par[prz->ecc_size];
45 /* Initialize the parity buffer */
46 memset(par, 0, sizeof(par));
47 encode_rs8(prz->rs_decoder, data, len, par, 0);
48 for (i = 0; i < prz->ecc_size; i++)
52 static int persistent_ram_decode_rs8(struct persistent_ram_zone *prz,
53 void *data, size_t len, uint8_t *ecc)
56 uint16_t par[prz->ecc_size];
58 for (i = 0; i < prz->ecc_size; i++)
60 return decode_rs8(prz->rs_decoder, data, par, len,
61 NULL, 0, NULL, 0, NULL);
64 static void notrace persistent_ram_update_ecc(struct persistent_ram_zone *prz,
67 struct persistent_ram_buffer *buffer = prz->buffer;
68 uint8_t *buffer_end = buffer->data + prz->buffer_size;
71 int ecc_block_size = prz->ecc_block_size;
72 int ecc_size = prz->ecc_size;
73 int size = prz->ecc_block_size;
78 block = buffer->data + (buffer->start & ~(ecc_block_size - 1));
79 par = prz->par_buffer +
80 (buffer->start / ecc_block_size) * prz->ecc_size;
82 if (block + ecc_block_size > buffer_end)
83 size = buffer_end - block;
84 persistent_ram_encode_rs8(prz, block, size, par);
85 block += ecc_block_size;
87 } while (block < buffer->data + buffer->start + count);
90 static void persistent_ram_update_header_ecc(struct persistent_ram_zone *prz)
92 struct persistent_ram_buffer *buffer = prz->buffer;
97 persistent_ram_encode_rs8(prz, (uint8_t *)buffer, sizeof(*buffer),
101 static void persistent_ram_ecc_old(struct persistent_ram_zone *prz)
103 struct persistent_ram_buffer *buffer = prz->buffer;
110 block = buffer->data;
111 par = prz->par_buffer;
112 while (block < buffer->data + buffer->size) {
114 int size = prz->ecc_block_size;
115 if (block + size > buffer->data + prz->buffer_size)
116 size = buffer->data + prz->buffer_size - block;
117 numerr = persistent_ram_decode_rs8(prz, block, size, par);
119 pr_devel("persistent_ram: error in block %p, %d\n",
121 prz->corrected_bytes += numerr;
122 } else if (numerr < 0) {
123 pr_devel("persistent_ram: uncorrectable error in block %p\n",
127 block += prz->ecc_block_size;
128 par += prz->ecc_size;
132 static int persistent_ram_init_ecc(struct persistent_ram_zone *prz,
136 struct persistent_ram_buffer *buffer = prz->buffer;
142 prz->ecc_block_size = 128;
144 prz->ecc_symsize = 8;
145 prz->ecc_poly = 0x11d;
147 ecc_blocks = DIV_ROUND_UP(prz->buffer_size, prz->ecc_block_size);
148 prz->buffer_size -= (ecc_blocks + 1) * prz->ecc_size;
150 if (prz->buffer_size > buffer_size) {
151 pr_err("persistent_ram: invalid size %zu, non-ecc datasize %zu\n",
152 buffer_size, prz->buffer_size);
156 prz->par_buffer = buffer->data + prz->buffer_size;
157 prz->par_header = prz->par_buffer + ecc_blocks * prz->ecc_size;
160 * first consecutive root is 0
161 * primitive element to generate roots = 1
163 prz->rs_decoder = init_rs(prz->ecc_symsize, prz->ecc_poly, 0, 1,
165 if (prz->rs_decoder == NULL) {
166 pr_info("persistent_ram: init_rs failed\n");
170 prz->corrected_bytes = 0;
173 numerr = persistent_ram_decode_rs8(prz, buffer, sizeof(*buffer),
176 pr_info("persistent_ram: error in header, %d\n", numerr);
177 prz->corrected_bytes += numerr;
178 } else if (numerr < 0) {
179 pr_info("persistent_ram: uncorrectable error in header\n");
186 ssize_t persistent_ram_ecc_string(struct persistent_ram_zone *prz,
187 char *str, size_t len)
191 if (prz->corrected_bytes || prz->bad_blocks)
192 ret = snprintf(str, len, ""
193 "\n%d Corrected bytes, %d unrecoverable blocks\n",
194 prz->corrected_bytes, prz->bad_blocks);
196 ret = snprintf(str, len, "\nNo errors detected\n");
201 static void notrace persistent_ram_update(struct persistent_ram_zone *prz,
202 const void *s, unsigned int count)
204 struct persistent_ram_buffer *buffer = prz->buffer;
205 memcpy(buffer->data + buffer->start, s, count);
206 persistent_ram_update_ecc(prz, count);
210 persistent_ram_save_old(struct persistent_ram_zone *prz)
212 struct persistent_ram_buffer *buffer = prz->buffer;
213 size_t old_log_size = buffer->size;
216 persistent_ram_ecc_old(prz);
218 dest = kmalloc(old_log_size, GFP_KERNEL);
220 pr_err("persistent_ram: failed to allocate buffer\n");
225 prz->old_log_size = old_log_size;
227 &buffer->data[buffer->start], buffer->size - buffer->start);
228 memcpy(prz->old_log + buffer->size - buffer->start,
229 &buffer->data[0], buffer->start);
232 int notrace persistent_ram_write(struct persistent_ram_zone *prz,
233 const void *s, unsigned int count)
237 struct persistent_ram_buffer *buffer = prz->buffer;
239 if (c > prz->buffer_size) {
240 s += c - prz->buffer_size;
241 c = prz->buffer_size;
243 rem = prz->buffer_size - buffer->start;
245 persistent_ram_update(prz, s, rem);
249 buffer->size = prz->buffer_size;
251 persistent_ram_update(prz, s, c);
254 if (buffer->size < prz->buffer_size)
256 persistent_ram_update_header_ecc(prz);
261 size_t persistent_ram_old_size(struct persistent_ram_zone *prz)
263 return prz->old_log_size;
266 void *persistent_ram_old(struct persistent_ram_zone *prz)
271 void persistent_ram_free_old(struct persistent_ram_zone *prz)
275 prz->old_log_size = 0;
278 static int persistent_ram_buffer_map(phys_addr_t start, phys_addr_t size,
279 struct persistent_ram_zone *prz)
282 phys_addr_t page_start;
283 unsigned int page_count;
287 page_start = start - offset_in_page(start);
288 page_count = DIV_ROUND_UP(size + offset_in_page(start), PAGE_SIZE);
290 prot = pgprot_noncached(PAGE_KERNEL);
292 pages = kmalloc(sizeof(struct page *) * page_count, GFP_KERNEL);
294 pr_err("%s: Failed to allocate array for %u pages\n", __func__,
299 for (i = 0; i < page_count; i++) {
300 phys_addr_t addr = page_start + i * PAGE_SIZE;
301 pages[i] = pfn_to_page(addr >> PAGE_SHIFT);
303 prz->vaddr = vmap(pages, page_count, VM_MAP, prot);
306 pr_err("%s: Failed to map %u pages\n", __func__, page_count);
310 prz->buffer = prz->vaddr + offset_in_page(start);
311 prz->buffer_size = size - sizeof(struct persistent_ram_buffer);
316 static int __init persistent_ram_buffer_init(const char *name,
317 struct persistent_ram_zone *prz)
320 struct persistent_ram *ram;
321 struct persistent_ram_descriptor *desc;
324 list_for_each_entry(ram, &persistent_ram_list, node) {
326 for (i = 0; i < ram->num_descs; i++) {
327 desc = &ram->descs[i];
328 if (!strcmp(desc->name, name))
329 return persistent_ram_buffer_map(start,
339 struct persistent_ram_zone *__persistent_ram_init(struct device *dev, bool ecc)
341 struct persistent_ram_zone *prz;
344 prz = kzalloc(sizeof(struct persistent_ram_zone), GFP_KERNEL);
346 pr_err("persistent_ram: failed to allocate persistent ram zone\n");
350 INIT_LIST_HEAD(&prz->node);
352 ret = persistent_ram_buffer_init(dev_name(dev), prz);
354 pr_err("persistent_ram: failed to initialize buffer\n");
359 ret = persistent_ram_init_ecc(prz, prz->buffer_size);
363 if (prz->buffer->sig == PERSISTENT_RAM_SIG) {
364 if (prz->buffer->size > prz->buffer_size
365 || prz->buffer->start > prz->buffer->size)
366 pr_info("persistent_ram: found existing invalid buffer, size %d, start %d\n",
367 prz->buffer->size, prz->buffer->start);
369 pr_info("persistent_ram: found existing buffer, size %d, start %d\n",
370 prz->buffer->size, prz->buffer->start);
371 persistent_ram_save_old(prz);
374 pr_info("persistent_ram: no valid data in buffer (sig = 0x%08x)\n",
378 prz->buffer->sig = PERSISTENT_RAM_SIG;
379 prz->buffer->start = 0;
380 prz->buffer->size = 0;
388 struct persistent_ram_zone * __init
389 persistent_ram_init_ringbuffer(struct device *dev, bool ecc)
391 return __persistent_ram_init(dev, ecc);
394 int __init persistent_ram_early_init(struct persistent_ram *ram)
398 ret = memblock_reserve(ram->start, ram->size);
400 pr_err("Failed to reserve persistent memory from %08lx-%08lx\n",
401 (long)ram->start, (long)(ram->start + ram->size - 1));
405 list_add_tail(&ram->node, &persistent_ram_list);
407 pr_info("Initialized persistent memory from %08lx-%08lx\n",
408 (long)ram->start, (long)(ram->start + ram->size - 1));