drivers/staging/android/ram_console.c

   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 <linux/io.h>
  24 #include "ram_console.h"
  25
  26 #ifdef CONFIG_ANDROID_RAM_CONSOLE_ERROR_CORRECTION
  27 #include <linux/rslib.h>
  28 #endif
  29
  30 struct ram_console_buffer {
  31         uint32_t    sig;
  32         uint32_t    start;
  33         uint32_t    size;
  34         uint8_t     data[0];
  35 };
  36
  37 #define RAM_CONSOLE_SIG (0x43474244) /* DBGC */
  38
  39 #ifdef CONFIG_ANDROID_RAM_CONSOLE_EARLY_INIT
  40 static char __initdata
  41         ram_console_old_log_init_buffer[CONFIG_ANDROID_RAM_CONSOLE_EARLY_SIZE];
  42 #endif
  43 static char *ram_console_old_log;
  44 static size_t ram_console_old_log_size;
  45
  46 static struct ram_console_buffer *ram_console_buffer;
  47 static size_t ram_console_buffer_size;
  48 #ifdef CONFIG_ANDROID_RAM_CONSOLE_ERROR_CORRECTION
  49 static char *ram_console_par_buffer;
  50 static struct rs_control *ram_console_rs_decoder;
  51 static int ram_console_corrected_bytes;
  52 static int ram_console_bad_blocks;
  53 #define ECC_BLOCK_SIZE CONFIG_ANDROID_RAM_CONSOLE_ERROR_CORRECTION_DATA_SIZE
  54 #define ECC_SIZE CONFIG_ANDROID_RAM_CONSOLE_ERROR_CORRECTION_ECC_SIZE
  55 #define ECC_SYMSIZE CONFIG_ANDROID_RAM_CONSOLE_ERROR_CORRECTION_SYMBOL_SIZE
  56 #define ECC_POLY CONFIG_ANDROID_RAM_CONSOLE_ERROR_CORRECTION_POLYNOMIAL
  57 #endif
  58
  59 #ifdef CONFIG_ANDROID_RAM_CONSOLE_ERROR_CORRECTION
  60 static void ram_console_encode_rs8(uint8_t *data, size_t len, uint8_t *ecc)
  61 {
  62         int i;
  63         uint16_t par[ECC_SIZE];
  64         /* Initialize the parity buffer */
  65         memset(par, 0, sizeof(par));
  66         encode_rs8(ram_console_rs_decoder, data, len, par, 0);
  67         for (i = 0; i < ECC_SIZE; i++)
  68                 ecc[i] = par[i];
  69 }
  70
  71 static int ram_console_decode_rs8(void *data, size_t len, uint8_t *ecc)
  72 {
  73         int i;
  74         uint16_t par[ECC_SIZE];
  75         for (i = 0; i < ECC_SIZE; i++)
  76                 par[i] = ecc[i];
  77         return decode_rs8(ram_console_rs_decoder, data, par, len,
  78                                 NULL, 0, NULL, 0, NULL);
  79 }
  80 #endif
  81
  82 static void ram_console_update(const char *s, unsigned int count)
  83 {
  84         struct ram_console_buffer *buffer = ram_console_buffer;
  85 #ifdef CONFIG_ANDROID_RAM_CONSOLE_ERROR_CORRECTION
  86         uint8_t *buffer_end = buffer->data + ram_console_buffer_size;
  87         uint8_t *block;
  88         uint8_t *par;
  89         int size = ECC_BLOCK_SIZE;
  90 #endif
  91         memcpy(buffer->data + buffer->start, s, count);
  92 #ifdef CONFIG_ANDROID_RAM_CONSOLE_ERROR_CORRECTION
  93         block = buffer->data + (buffer->start & ~(ECC_BLOCK_SIZE - 1));
  94         par = ram_console_par_buffer +
  95               (buffer->start / ECC_BLOCK_SIZE) * ECC_SIZE;
  96         do {
  97                 if (block + ECC_BLOCK_SIZE > buffer_end)
  98                         size = buffer_end - block;
  99                 ram_console_encode_rs8(block, size, par);
 100                 block += ECC_BLOCK_SIZE;
 101                 par += ECC_SIZE;
 102         } while (block < buffer->data + buffer->start + count);
 103 #endif
 104 }
 105
 106 static void ram_console_update_header(void)
 107 {
 108 #ifdef CONFIG_ANDROID_RAM_CONSOLE_ERROR_CORRECTION
 109         struct ram_console_buffer *buffer = ram_console_buffer;
 110         uint8_t *par;
 111         par = ram_console_par_buffer +
 112               DIV_ROUND_UP(ram_console_buffer_size, ECC_BLOCK_SIZE) * ECC_SIZE;
 113         ram_console_encode_rs8((uint8_t *)buffer, sizeof(*buffer), par);
 114 #endif
 115 }
 116
 117 static void
 118 ram_console_write(struct console *console, const char *s, unsigned int count)
 119 {
 120         int rem;
 121         struct ram_console_buffer *buffer = ram_console_buffer;
 122
 123         if (count > ram_console_buffer_size) {
 124                 s += count - ram_console_buffer_size;
 125                 count = ram_console_buffer_size;
 126         }
 127         rem = ram_console_buffer_size - buffer->start;
 128         if (rem < count) {
 129                 ram_console_update(s, rem);
 130                 s += rem;
 131                 count -= rem;
 132                 buffer->start = 0;
 133                 buffer->size = ram_console_buffer_size;
 134         }
 135         ram_console_update(s, count);
 136
 137         buffer->start += count;
 138         if (buffer->size < ram_console_buffer_size)
 139                 buffer->size += count;
 140         ram_console_update_header();
 141 }
 142
 143 static struct console ram_console = {
 144         .name   = "ram",
 145         .write  = ram_console_write,
 146         .flags  = CON_PRINTBUFFER | CON_ENABLED,
 147         .index  = -1,
 148 };
 149
 150 void ram_console_enable_console(int enabled)
 151 {
 152         if (enabled)
 153                 ram_console.flags |= CON_ENABLED;
 154         else
 155                 ram_console.flags &= ~CON_ENABLED;
 156 }
 157
 158 static void __init
 159 ram_console_save_old(struct ram_console_buffer *buffer, const char *bootinfo,
 160         char *dest)
 161 {
 162         size_t old_log_size = buffer->size;
 163         size_t bootinfo_size = 0;
 164         size_t total_size = old_log_size;
 165         char *ptr;
 166         const char *bootinfo_label = "Boot info:\n";
 167
 168 #ifdef CONFIG_ANDROID_RAM_CONSOLE_ERROR_CORRECTION
 169         uint8_t *block;
 170         uint8_t *par;
 171         char strbuf[80];
 172         int strbuf_len = 0;
 173
 174         block = buffer->data;
 175         par = ram_console_par_buffer;
 176         while (block < buffer->data + buffer->size) {
 177                 int numerr;
 178                 int size = ECC_BLOCK_SIZE;
 179                 if (block + size > buffer->data + ram_console_buffer_size)
 180                         size = buffer->data + ram_console_buffer_size - block;
 181                 numerr = ram_console_decode_rs8(block, size, par);
 182                 if (numerr > 0) {
 183 #if 0
 184                         printk(KERN_INFO "ram_console: error in block %p, %d\n",
 185                                block, numerr);
 186 #endif
 187                         ram_console_corrected_bytes += numerr;
 188                 } else if (numerr < 0) {
 189 #if 0
 190                         printk(KERN_INFO "ram_console: uncorrectable error in "
 191                                "block %p\n", block);
 192 #endif
 193                         ram_console_bad_blocks++;
 194                 }
 195                 block += ECC_BLOCK_SIZE;
 196                 par += ECC_SIZE;
 197         }
 198         if (ram_console_corrected_bytes || ram_console_bad_blocks)
 199                 strbuf_len = snprintf(strbuf, sizeof(strbuf),
 200                         "\n%d Corrected bytes, %d unrecoverable blocks\n",
 201                         ram_console_corrected_bytes, ram_console_bad_blocks);
 202         else
 203                 strbuf_len = snprintf(strbuf, sizeof(strbuf),
 204                                       "\nNo errors detected\n");
 205         if (strbuf_len >= sizeof(strbuf))
 206                 strbuf_len = sizeof(strbuf) - 1;
 207         total_size += strbuf_len;
 208 #endif
 209
 210         if (bootinfo)
 211                 bootinfo_size = strlen(bootinfo) + strlen(bootinfo_label);
 212         total_size += bootinfo_size;
 213
 214         if (dest == NULL) {
 215                 dest = kmalloc(total_size, GFP_KERNEL);
 216                 if (dest == NULL) {
 217                         printk(KERN_ERR
 218                                "ram_console: failed to allocate buffer\n");
 219                         return;
 220                 }
 221         }
 222
 223         ram_console_old_log = dest;
 224         ram_console_old_log_size = total_size;
 225         memcpy(ram_console_old_log,
 226                &buffer->data[buffer->start], buffer->size - buffer->start);
 227         memcpy(ram_console_old_log + buffer->size - buffer->start,
 228                &buffer->data[0], buffer->start);
 229         ptr = ram_console_old_log + old_log_size;
 230 #ifdef CONFIG_ANDROID_RAM_CONSOLE_ERROR_CORRECTION
 231         memcpy(ptr, strbuf, strbuf_len);
 232         ptr += strbuf_len;
 233 #endif
 234         if (bootinfo) {
 235                 memcpy(ptr, bootinfo_label, strlen(bootinfo_label));
 236                 ptr += strlen(bootinfo_label);
 237                 memcpy(ptr, bootinfo, bootinfo_size);
 238                 ptr += bootinfo_size;
 239         }
 240 }
 241
 242 static int __init ram_console_init(struct ram_console_buffer *buffer,
 243                                    size_t buffer_size, const char *bootinfo,
 244                                    char *old_buf)
 245 {
 246 #ifdef CONFIG_ANDROID_RAM_CONSOLE_ERROR_CORRECTION
 247         int numerr;
 248         uint8_t *par;
 249 #endif
 250         ram_console_buffer = buffer;
 251         ram_console_buffer_size =
 252                 buffer_size - sizeof(struct ram_console_buffer);
 253
 254         if (ram_console_buffer_size > buffer_size) {
 255                 pr_err("ram_console: buffer %p, invalid size %zu, "
 256                        "datasize %zu\n", buffer, buffer_size,
 257                        ram_console_buffer_size);
 258                 return 0;
 259         }
 260
 261 #ifdef CONFIG_ANDROID_RAM_CONSOLE_ERROR_CORRECTION
 262         ram_console_buffer_size -= (DIV_ROUND_UP(ram_console_buffer_size,
 263                                                 ECC_BLOCK_SIZE) + 1) * ECC_SIZE;
 264
 265         if (ram_console_buffer_size > buffer_size) {
 266                 pr_err("ram_console: buffer %p, invalid size %zu, "
 267                        "non-ecc datasize %zu\n",
 268                        buffer, buffer_size, ram_console_buffer_size);
 269                 return 0;
 270         }
 271
 272         ram_console_par_buffer = buffer->data + ram_console_buffer_size;
 273
 274
 275         /* first consecutive root is 0
 276          * primitive element to generate roots = 1
 277          */
 278         ram_console_rs_decoder = init_rs(ECC_SYMSIZE, ECC_POLY, 0, 1, ECC_SIZE);
 279         if (ram_console_rs_decoder == NULL) {
 280                 printk(KERN_INFO "ram_console: init_rs failed\n");
 281                 return 0;
 282         }
 283
 284         ram_console_corrected_bytes = 0;
 285         ram_console_bad_blocks = 0;
 286
 287         par = ram_console_par_buffer +
 288               DIV_ROUND_UP(ram_console_buffer_size, ECC_BLOCK_SIZE) * ECC_SIZE;
 289
 290         numerr = ram_console_decode_rs8(buffer, sizeof(*buffer), par);
 291         if (numerr > 0) {
 292                 printk(KERN_INFO "ram_console: error in header, %d\n", numerr);
 293                 ram_console_corrected_bytes += numerr;
 294         } else if (numerr < 0) {
 295                 printk(KERN_INFO
 296                        "ram_console: uncorrectable error in header\n");
 297                 ram_console_bad_blocks++;
 298         }
 299 #endif
 300
 301         if (buffer->sig == RAM_CONSOLE_SIG) {
 302                 if (buffer->size > ram_console_buffer_size
 303                     || buffer->start > buffer->size)
 304                         printk(KERN_INFO "ram_console: found existing invalid "
 305                                "buffer, size %d, start %d\n",
 306                                buffer->size, buffer->start);
 307                 else {
 308                         printk(KERN_INFO "ram_console: found existing buffer, "
 309                                "size %d, start %d\n",
 310                                buffer->size, buffer->start);
 311                         ram_console_save_old(buffer, bootinfo, old_buf);
 312                 }
 313         } else {
 314                 printk(KERN_INFO "ram_console: no valid data in buffer "
 315                        "(sig = 0x%08x)\n", buffer->sig);
 316         }
 317
 318         buffer->sig = RAM_CONSOLE_SIG;
 319         buffer->start = 0;
 320         buffer->size = 0;
 321
 322         register_console(&ram_console);
 323 #ifdef CONFIG_ANDROID_RAM_CONSOLE_ENABLE_VERBOSE
 324         console_verbose();
 325 #endif
 326         return 0;
 327 }
 328
 329 #ifdef CONFIG_ANDROID_RAM_CONSOLE_EARLY_INIT
 330 static int __init ram_console_early_init(void)
 331 {
 332         return ram_console_init((struct ram_console_buffer *)
 333                 CONFIG_ANDROID_RAM_CONSOLE_EARLY_ADDR,
 334                 CONFIG_ANDROID_RAM_CONSOLE_EARLY_SIZE,
 335                 NULL,
 336                 ram_console_old_log_init_buffer);
 337 }
 338 #else
 339 static int ram_console_driver_probe(struct platform_device *pdev)
 340 {
 341         struct resource *res = pdev->resource;
 342         size_t start;
 343         size_t buffer_size;
 344         void *buffer;
 345         const char *bootinfo = NULL;
 346         struct ram_console_platform_data *pdata = pdev->dev.platform_data;
 347
 348         if (res == NULL || pdev->num_resources != 1 ||
 349             !(res->flags & IORESOURCE_MEM)) {
 350                 printk(KERN_ERR "ram_console: invalid resource, %p %d flags "
 351                        "%lx\n", res, pdev->num_resources, res ? res->flags : 0);
 352                 return -ENXIO;
 353         }
 354         buffer_size = res->end - res->start + 1;
 355         start = res->start;
 356         printk(KERN_INFO "ram_console: got buffer at %zx, size %zx\n",
 357                start, buffer_size);
 358         buffer = ioremap(res->start, buffer_size);
 359         if (buffer == NULL) {
 360                 printk(KERN_ERR "ram_console: failed to map memory\n");
 361                 return -ENOMEM;
 362         }
 363
 364         if (pdata)
 365                 bootinfo = pdata->bootinfo;
 366
 367         return ram_console_init(buffer, buffer_size, bootinfo, NULL/* allocate */);
 368 }
 369
 370 static struct platform_driver ram_console_driver = {
 371         .probe = ram_console_driver_probe,
 372         .driver         = {
 373                 .name   = "ram_console",
 374         },
 375 };
 376
 377 static int __init ram_console_module_init(void)
 378 {
 379         int err;
 380         err = platform_driver_register(&ram_console_driver);
 381         return err;
 382 }
 383 #endif
 384
 385 static ssize_t ram_console_read_old(struct file *file, char __user *buf,
 386                                     size_t len, loff_t *offset)
 387 {
 388         loff_t pos = *offset;
 389         ssize_t count;
 390
 391         if (pos >= ram_console_old_log_size)
 392                 return 0;
 393
 394         count = min(len, (size_t)(ram_console_old_log_size - pos));
 395         if (copy_to_user(buf, ram_console_old_log + pos, count))
 396                 return -EFAULT;
 397
 398         *offset += count;
 399         return count;
 400 }
 401
 402 static const struct file_operations ram_console_file_ops = {
 403         .owner = THIS_MODULE,
 404         .read = ram_console_read_old,
 405 };
 406
 407 static int __init ram_console_late_init(void)
 408 {
 409         struct proc_dir_entry *entry;
 410
 411         if (ram_console_old_log == NULL)
 412                 return 0;
 413 #ifdef CONFIG_ANDROID_RAM_CONSOLE_EARLY_INIT
 414         ram_console_old_log = kmalloc(ram_console_old_log_size, GFP_KERNEL);
 415         if (ram_console_old_log == NULL) {
 416                 printk(KERN_ERR
 417                        "ram_console: failed to allocate buffer for old log\n");
 418                 ram_console_old_log_size = 0;
 419                 return 0;
 420         }
 421         memcpy(ram_console_old_log,
 422                ram_console_old_log_init_buffer, ram_console_old_log_size);
 423 #endif
 424         entry = create_proc_entry("last_kmsg", S_IFREG | S_IRUGO, NULL);
 425         if (!entry) {
 426                 printk(KERN_ERR "ram_console: failed to create proc entry\n");
 427                 kfree(ram_console_old_log);
 428                 ram_console_old_log = NULL;
 429                 return 0;
 430         }
 431
 432         entry->proc_fops = &ram_console_file_ops;
 433         entry->size = ram_console_old_log_size;
 434         return 0;
 435 }
 436
 437 #ifdef CONFIG_ANDROID_RAM_CONSOLE_EARLY_INIT
 438 console_initcall(ram_console_early_init);
 439 #else
 440 postcore_initcall(ram_console_module_init);
 441 #endif
 442 late_initcall(ram_console_late_init);
 443