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   1 /* drivers/android/ram_console.c
   2  *
   3  * Copyright (C) 2007-2008 Google, Inc.
   4  *
   5  * This software is licensed under the terms of the GNU General Public
   6  * License version 2, as published by the Free Software Foundation, and
   7  * may be copied, distributed, and modified under those terms.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  */
  15
  16 #include <linux/console.h>
  17 #include <linux/init.h>
  18 #include <linux/module.h>
  19 #include <linux/platform_device.h>
  20 #include <linux/proc_fs.h>
  21 #include <linux/string.h>
  22 #include <linux/uaccess.h>
  23 #include <asm/io.h>
  24
  25 #ifdef CONFIG_ANDROID_RAM_CONSOLE_ERROR_CORRECTION
  26 #include <linux/rslib.h>
  27 #endif
  28
  29 struct ram_console_buffer {
  30         uint32_t    sig;
  31         uint32_t    start;
  32         uint32_t    size;
  33         uint8_t     data[0];
  34 };
  35
  36 #define RAM_CONSOLE_SIG (0x43474244) /* DBGC */
  37
  38 #ifdef CONFIG_ANDROID_RAM_CONSOLE_EARLY_INIT
  39 static char __initdata
  40         ram_console_old_log_init_buffer[CONFIG_ANDROID_RAM_CONSOLE_EARLY_SIZE];
  41 #endif
  42 static char *ram_console_old_log;
  43 static size_t ram_console_old_log_size;
  44
  45 static struct ram_console_buffer *ram_console_buffer;
  46 static size_t ram_console_buffer_size;
  47 #ifdef CONFIG_ANDROID_RAM_CONSOLE_ERROR_CORRECTION
  48 static char *ram_console_par_buffer;
  49 static struct rs_control *ram_console_rs_decoder;
  50 static int ram_console_corrected_bytes;
  51 static int ram_console_bad_blocks;
  52 #define ECC_BLOCK_SIZE CONFIG_ANDROID_RAM_CONSOLE_ERROR_CORRECTION_DATA_SIZE
  53 #define ECC_SIZE CONFIG_ANDROID_RAM_CONSOLE_ERROR_CORRECTION_ECC_SIZE
  54 #define ECC_SYMSIZE CONFIG_ANDROID_RAM_CONSOLE_ERROR_CORRECTION_SYMBOL_SIZE
  55 #define ECC_POLY CONFIG_ANDROID_RAM_CONSOLE_ERROR_CORRECTION_POLYNOMIAL
  56 #endif
  57
  58 #ifdef CONFIG_ANDROID_RAM_CONSOLE_ERROR_CORRECTION
  59 static void ram_console_encode_rs8(uint8_t *data, size_t len, uint8_t *ecc)
  60 {
  61         int i;
  62         uint16_t par[ECC_SIZE];
  63         /* Initialize the parity buffer */
  64         memset(par, 0, sizeof(par));
  65         encode_rs8(ram_console_rs_decoder, data, len, par, 0);
  66         for (i = 0; i < ECC_SIZE; i++)
  67                 ecc[i] = par[i];
  68 }
  69
  70 static int ram_console_decode_rs8(void *data, size_t len, uint8_t *ecc)
  71 {
  72         int i;
  73         uint16_t par[ECC_SIZE];
  74         for (i = 0; i < ECC_SIZE; i++)
  75                 par[i] = ecc[i];
  76         return decode_rs8(ram_console_rs_decoder, data, par, len,
  77                                 NULL, 0, NULL, 0, NULL);
  78 }
  79 #endif
  80
  81 static void ram_console_update(const char *s, unsigned int count)
  82 {
  83         struct ram_console_buffer *buffer = ram_console_buffer;
  84 #ifdef CONFIG_ANDROID_RAM_CONSOLE_ERROR_CORRECTION
  85         uint8_t *buffer_end = buffer->data + ram_console_buffer_size;
  86         uint8_t *block;
  87         uint8_t *par;
  88         int size = ECC_BLOCK_SIZE;
  89 #endif
  90         memcpy(buffer->data + buffer->start, s, count);
  91 #ifdef CONFIG_ANDROID_RAM_CONSOLE_ERROR_CORRECTION
  92         block = buffer->data + (buffer->start & ~(ECC_BLOCK_SIZE - 1));
  93         par = ram_console_par_buffer +
  94               (buffer->start / ECC_BLOCK_SIZE) * ECC_SIZE;
  95         do {
  96                 if (block + ECC_BLOCK_SIZE > buffer_end)
  97                         size = buffer_end - block;
  98                 ram_console_encode_rs8(block, size, par);
  99                 block += ECC_BLOCK_SIZE;
 100                 par += ECC_SIZE;
 101         } while (block < buffer->data + buffer->start + count);
 102 #endif
 103 }
 104
 105 static void ram_console_update_header(void)
 106 {
 107 #ifdef CONFIG_ANDROID_RAM_CONSOLE_ERROR_CORRECTION
 108         struct ram_console_buffer *buffer = ram_console_buffer;
 109         uint8_t *par;
 110         par = ram_console_par_buffer +
 111               DIV_ROUND_UP(ram_console_buffer_size, ECC_BLOCK_SIZE) * ECC_SIZE;
 112         ram_console_encode_rs8((uint8_t *)buffer, sizeof(*buffer), par);
 113 #endif
 114 }
 115
 116 static void
 117 ram_console_write(struct console *console, const char *s, unsigned int count)
 118 {
 119         int rem;
 120         struct ram_console_buffer *buffer = ram_console_buffer;
 121
 122         if (count > ram_console_buffer_size) {
 123                 s += count - ram_console_buffer_size;
 124                 count = ram_console_buffer_size;
 125         }
 126         rem = ram_console_buffer_size - buffer->start;
 127         if (rem < count) {
 128                 ram_console_update(s, rem);
 129                 s += rem;
 130                 count -= rem;
 131                 buffer->start = 0;
 132                 buffer->size = ram_console_buffer_size;
 133         }
 134         ram_console_update(s, count);
 135
 136         buffer->start += count;
 137         if (buffer->size < ram_console_buffer_size)
 138                 buffer->size += count;
 139         ram_console_update_header();
 140 }
 141
 142 static struct console ram_console = {
 143         .name   = "ram",
 144         .write  = ram_console_write,
 145         .flags  = CON_PRINTBUFFER | CON_ENABLED,
 146         .index  = -1,
 147 };
 148
 149 static void __init
 150 ram_console_save_old(struct ram_console_buffer *buffer, char *dest)
 151 {
 152         size_t old_log_size = buffer->size;
 153 #ifdef CONFIG_ANDROID_RAM_CONSOLE_ERROR_CORRECTION
 154         uint8_t *block;
 155         uint8_t *par;
 156         char strbuf[80];
 157         int strbuf_len;
 158
 159         block = buffer->data;
 160         par = ram_console_par_buffer;
 161         while (block < buffer->data + buffer->size) {
 162                 int numerr;
 163                 int size = ECC_BLOCK_SIZE;
 164                 if (block + size > buffer->data + ram_console_buffer_size)
 165                         size = buffer->data + ram_console_buffer_size - block;
 166                 numerr = ram_console_decode_rs8(block, size, par);
 167                 if (numerr > 0) {
 168 #if 0
 169                         printk(KERN_INFO "ram_console: error in block %p, %d\n",
 170                                block, numerr);
 171 #endif
 172                         ram_console_corrected_bytes += numerr;
 173                 } else if (numerr < 0) {
 174 #if 0
 175                         printk(KERN_INFO "ram_console: uncorrectable error in "
 176                                "block %p\n", block);
 177 #endif
 178                         ram_console_bad_blocks++;
 179                 }
 180                 block += ECC_BLOCK_SIZE;
 181                 par += ECC_SIZE;
 182         }
 183         if (ram_console_corrected_bytes || ram_console_bad_blocks)
 184                 strbuf_len = snprintf(strbuf, sizeof(strbuf),
 185                         "\n%d Corrected bytes, %d unrecoverable blocks\n",
 186                         ram_console_corrected_bytes, ram_console_bad_blocks);
 187         else
 188                 strbuf_len = snprintf(strbuf, sizeof(strbuf),
 189                                       "\nNo errors detected\n");
 190         if (strbuf_len >= sizeof(strbuf))
 191                 strbuf_len = sizeof(strbuf) - 1;
 192         old_log_size += strbuf_len;
 193 #endif
 194
 195         if (dest == NULL) {
 196                 dest = kmalloc(old_log_size, GFP_KERNEL);
 197                 if (dest == NULL) {
 198                         printk(KERN_ERR
 199                                "ram_console: failed to allocate buffer\n");
 200                         return;
 201                 }
 202         }
 203
 204         ram_console_old_log = dest;
 205         ram_console_old_log_size = old_log_size;
 206         memcpy(ram_console_old_log,
 207                &buffer->data[buffer->start], buffer->size - buffer->start);
 208         memcpy(ram_console_old_log + buffer->size - buffer->start,
 209                &buffer->data[0], buffer->start);
 210 #ifdef CONFIG_ANDROID_RAM_CONSOLE_ERROR_CORRECTION
 211         memcpy(ram_console_old_log + old_log_size - strbuf_len,
 212                strbuf, strbuf_len);
 213 #endif
 214 }
 215
 216 static int __init ram_console_init(struct ram_console_buffer *buffer,
 217                                    size_t buffer_size, char *old_buf)
 218 {
 219 #ifdef CONFIG_ANDROID_RAM_CONSOLE_ERROR_CORRECTION
 220         int numerr;
 221         uint8_t *par;
 222 #endif
 223         ram_console_buffer = buffer;
 224         ram_console_buffer_size =
 225                 buffer_size - sizeof(struct ram_console_buffer);
 226
 227         if (ram_console_buffer_size > buffer_size) {
 228                 pr_err("ram_console: buffer %p, invalid size %zu, datasize %zu\n",
 229                        buffer, buffer_size, ram_console_buffer_size);
 230                 return 0;
 231         }
 232
 233 #ifdef CONFIG_ANDROID_RAM_CONSOLE_ERROR_CORRECTION
 234         ram_console_buffer_size -= (DIV_ROUND_UP(ram_console_buffer_size,
 235                                                 ECC_BLOCK_SIZE) + 1) * ECC_SIZE;
 236
 237         if (ram_console_buffer_size > buffer_size) {
 238                 pr_err("ram_console: buffer %p, invalid size %zu, "
 239                        "non-ecc datasize %zu\n",
 240                        buffer, buffer_size, ram_console_buffer_size);
 241                 return 0;
 242         }
 243
 244         ram_console_par_buffer = buffer->data + ram_console_buffer_size;
 245
 246
 247         /* first consecutive root is 0
 248          * primitive element to generate roots = 1
 249          */
 250         ram_console_rs_decoder = init_rs(ECC_SYMSIZE, ECC_POLY, 0, 1, ECC_SIZE);
 251         if (ram_console_rs_decoder == NULL) {
 252                 printk(KERN_INFO "ram_console: init_rs failed\n");
 253                 return 0;
 254         }
 255
 256         ram_console_corrected_bytes = 0;
 257         ram_console_bad_blocks = 0;
 258
 259         par = ram_console_par_buffer +
 260               DIV_ROUND_UP(ram_console_buffer_size, ECC_BLOCK_SIZE) * ECC_SIZE;
 261
 262         numerr = ram_console_decode_rs8(buffer, sizeof(*buffer), par);
 263         if (numerr > 0) {
 264                 printk(KERN_INFO "ram_console: error in header, %d\n", numerr);
 265                 ram_console_corrected_bytes += numerr;
 266         } else if (numerr < 0) {
 267                 printk(KERN_INFO
 268                        "ram_console: uncorrectable error in header\n");
 269                 ram_console_bad_blocks++;
 270         }
 271 #endif
 272
 273         if (buffer->sig == RAM_CONSOLE_SIG) {
 274                 if (buffer->size > ram_console_buffer_size
 275                     || buffer->start > buffer->size)
 276                         printk(KERN_INFO "ram_console: found existing invalid "
 277                                "buffer, size %d, start %d\n",
 278                                buffer->size, buffer->start);
 279                 else {
 280                         printk(KERN_INFO "ram_console: found existing buffer, "
 281                                "size %d, start %d\n",
 282                                buffer->size, buffer->start);
 283                         ram_console_save_old(buffer, old_buf);
 284                 }
 285         } else {
 286                 printk(KERN_INFO "ram_console: no valid data in buffer "
 287                        "(sig = 0x%08x)\n", buffer->sig);
 288         }
 289
 290         buffer->sig = RAM_CONSOLE_SIG;
 291         buffer->start = 0;
 292         buffer->size = 0;
 293
 294         register_console(&ram_console);
 295 #ifdef CONFIG_ANDROID_RAM_CONSOLE_ENABLE_VERBOSE
 296         console_verbose();
 297 #endif
 298         return 0;
 299 }
 300
 301 #ifdef CONFIG_ANDROID_RAM_CONSOLE_EARLY_INIT
 302 static int __init ram_console_early_init(void)
 303 {
 304         return ram_console_init((struct ram_console_buffer *)
 305                 CONFIG_ANDROID_RAM_CONSOLE_EARLY_ADDR,
 306                 CONFIG_ANDROID_RAM_CONSOLE_EARLY_SIZE,
 307                 ram_console_old_log_init_buffer);
 308 }
 309 #else
 310 static int ram_console_driver_probe(struct platform_device *pdev)
 311 {
 312         struct resource *res = pdev->resource;
 313         size_t start;
 314         size_t buffer_size;
 315         void *buffer;
 316
 317         if (res == NULL || pdev->num_resources != 1 ||
 318             !(res->flags & IORESOURCE_MEM)) {
 319                 printk(KERN_ERR "ram_console: invalid resource, %p %d flags "
 320                        "%lx\n", res, pdev->num_resources, res ? res->flags : 0);
 321                 return -ENXIO;
 322         }
 323         buffer_size = res->end - res->start + 1;
 324         start = res->start;
 325         printk(KERN_INFO "ram_console: got buffer at %zx, size %zx\n",
 326                start, buffer_size);
 327         buffer = ioremap(res->start, buffer_size);
 328         if (buffer == NULL) {
 329                 printk(KERN_ERR "ram_console: failed to map memory\n");
 330                 return -ENOMEM;
 331         }
 332
 333         return ram_console_init(buffer, buffer_size, NULL/* allocate */);
 334 }
 335
 336 static struct platform_driver ram_console_driver = {
 337         .probe = ram_console_driver_probe,
 338         .driver         = {
 339                 .name   = "ram_console",
 340         },
 341 };
 342
 343 static int __init ram_console_module_init(void)
 344 {
 345         int err;
 346         err = platform_driver_register(&ram_console_driver);
 347         return err;
 348 }
 349 #endif
 350
 351 static ssize_t ram_console_read_old(struct file *file, char __user *buf,
 352                                     size_t len, loff_t *offset)
 353 {
 354         loff_t pos = *offset;
 355         ssize_t count;
 356
 357         if (pos >= ram_console_old_log_size)
 358                 return 0;
 359
 360         count = min(len, (size_t)(ram_console_old_log_size - pos));
 361         if (copy_to_user(buf, ram_console_old_log + pos, count))
 362                 return -EFAULT;
 363
 364         *offset += count;
 365         return count;
 366 }
 367
 368 static struct file_operations ram_console_file_ops = {
 369         .owner = THIS_MODULE,
 370         .read = ram_console_read_old,
 371 };
 372
 373 static int __init ram_console_late_init(void)
 374 {
 375         struct proc_dir_entry *entry;
 376
 377         if (ram_console_old_log == NULL)
 378                 return 0;
 379 #ifdef CONFIG_ANDROID_RAM_CONSOLE_EARLY_INIT
 380         ram_console_old_log = kmalloc(ram_console_old_log_size, GFP_KERNEL);
 381         if (ram_console_old_log == NULL) {
 382                 printk(KERN_ERR
 383                        "ram_console: failed to allocate buffer for old log\n");
 384                 ram_console_old_log_size = 0;
 385                 return 0;
 386         }
 387         memcpy(ram_console_old_log,
 388                ram_console_old_log_init_buffer, ram_console_old_log_size);
 389 #endif
 390         entry = create_proc_entry("last_kmsg", S_IFREG | S_IRUGO, NULL);
 391         if (!entry) {
 392                 printk(KERN_ERR "ram_console: failed to create proc entry\n");
 393                 kfree(ram_console_old_log);
 394                 ram_console_old_log = NULL;
 395                 return 0;
 396         }
 397
 398         entry->proc_fops = &ram_console_file_ops;
 399         entry->size = ram_console_old_log_size;
 400         return 0;
 401 }
 402
 403 #ifdef CONFIG_ANDROID_RAM_CONSOLE_EARLY_INIT
 404 console_initcall(ram_console_early_init);
 405 #else
 406 module_init(ram_console_module_init);
 407 #endif
 408 late_initcall(ram_console_late_init);
 409