drivers/mtd/mtdoops.c

   1 /*
   2  * MTD Oops/Panic logger
   3  *
   4  * Copyright (C) 2007 Nokia Corporation. All rights reserved.
   5  *
   6  * Author: Richard Purdie <rpurdie@openedhand.com>
   7  *
   8  * This program is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU General Public License
  10  * version 2 as published by the Free Software Foundation.
  11  *
  12  * This program is distributed in the hope that it will be useful, but
  13  * WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
  20  * 02110-1301 USA
  21  *
  22  */
  23
  24 #include <linux/kernel.h>
  25 #include <linux/module.h>
  26 #include <linux/console.h>
  27 #include <linux/vmalloc.h>
  28 #include <linux/workqueue.h>
  29 #include <linux/sched.h>
  30 #include <linux/wait.h>
  31 #include <linux/delay.h>
  32 #include <linux/spinlock.h>
  33 #include <linux/interrupt.h>
  34 #include <linux/mtd/mtd.h>
  35
  36 /* Maximum MTD partition size */
  37 #define MTDOOPS_MAX_MTD_SIZE (8 * 1024 * 1024)
  38
  39 #define MTDOOPS_KERNMSG_MAGIC 0x5d005d00
  40 #define OOPS_PAGE_SIZE 4096
  41
  42 static struct mtdoops_context {
  43         int mtd_index;
  44         struct work_struct work_erase;
  45         struct work_struct work_write;
  46         struct mtd_info *mtd;
  47         int oops_pages;
  48         int nextpage;
  49         int nextcount;
  50         unsigned long *oops_page_used;
  51         char *name;
  52
  53         void *oops_buf;
  54
  55         /* writecount and disabling ready are spin lock protected */
  56         spinlock_t writecount_lock;
  57         int ready;
  58         int writecount;
  59 } oops_cxt;
  60
  61 static void mark_page_used(struct mtdoops_context *cxt, int page)
  62 {
  63         set_bit(page, cxt->oops_page_used);
  64 }
  65
  66 static void mark_page_unused(struct mtdoops_context *cxt, int page)
  67 {
  68         clear_bit(page, cxt->oops_page_used);
  69 }
  70
  71 static int page_is_used(struct mtdoops_context *cxt, int page)
  72 {
  73         return test_bit(page, cxt->oops_page_used);
  74 }
  75
  76 static void mtdoops_erase_callback(struct erase_info *done)
  77 {
  78         wait_queue_head_t *wait_q = (wait_queue_head_t *)done->priv;
  79         wake_up(wait_q);
  80 }
  81
  82 static int mtdoops_erase_block(struct mtdoops_context *cxt, int offset)
  83 {
  84         struct mtd_info *mtd = cxt->mtd;
  85         u32 start_page_offset = mtd_div_by_eb(offset, mtd) * mtd->erasesize;
  86         u32 start_page = start_page_offset / OOPS_PAGE_SIZE;
  87         u32 erase_pages = mtd->erasesize / OOPS_PAGE_SIZE;
  88         struct erase_info erase;
  89         DECLARE_WAITQUEUE(wait, current);
  90         wait_queue_head_t wait_q;
  91         int ret;
  92         int page;
  93
  94         init_waitqueue_head(&wait_q);
  95         erase.mtd = mtd;
  96         erase.callback = mtdoops_erase_callback;
  97         erase.addr = offset;
  98         erase.len = mtd->erasesize;
  99         erase.priv = (u_long)&wait_q;
 100
 101         set_current_state(TASK_INTERRUPTIBLE);
 102         add_wait_queue(&wait_q, &wait);
 103
 104         ret = mtd->erase(mtd, &erase);
 105         if (ret) {
 106                 set_current_state(TASK_RUNNING);
 107                 remove_wait_queue(&wait_q, &wait);
 108                 printk(KERN_WARNING "mtdoops: erase of region [0x%llx, 0x%llx] on \"%s\" failed\n",
 109                        (unsigned long long)erase.addr,
 110                        (unsigned long long)erase.len, mtd->name);
 111                 return ret;
 112         }
 113
 114         schedule();  /* Wait for erase to finish. */
 115         remove_wait_queue(&wait_q, &wait);
 116
 117         /* Mark pages as unused */
 118         for (page = start_page; page < start_page + erase_pages; page++)
 119                 mark_page_unused(cxt, page);
 120
 121         return 0;
 122 }
 123
 124 static void mtdoops_inc_counter(struct mtdoops_context *cxt)
 125 {
 126         cxt->nextpage++;
 127         if (cxt->nextpage >= cxt->oops_pages)
 128                 cxt->nextpage = 0;
 129         cxt->nextcount++;
 130         if (cxt->nextcount == 0xffffffff)
 131                 cxt->nextcount = 0;
 132
 133         if (page_is_used(cxt, cxt->nextpage)) {
 134                 schedule_work(&cxt->work_erase);
 135                 return;
 136         }
 137
 138         printk(KERN_DEBUG "mtdoops: ready %d, %d (no erase)\n",
 139                cxt->nextpage, cxt->nextcount);
 140         cxt->ready = 1;
 141 }
 142
 143 /* Scheduled work - when we can't proceed without erasing a block */
 144 static void mtdoops_workfunc_erase(struct work_struct *work)
 145 {
 146         struct mtdoops_context *cxt =
 147                         container_of(work, struct mtdoops_context, work_erase);
 148         struct mtd_info *mtd = cxt->mtd;
 149         int i = 0, j, ret, mod;
 150
 151         /* We were unregistered */
 152         if (!mtd)
 153                 return;
 154
 155         mod = (cxt->nextpage * OOPS_PAGE_SIZE) % mtd->erasesize;
 156         if (mod != 0) {
 157                 cxt->nextpage = cxt->nextpage + ((mtd->erasesize - mod) / OOPS_PAGE_SIZE);
 158                 if (cxt->nextpage >= cxt->oops_pages)
 159                         cxt->nextpage = 0;
 160         }
 161
 162         while (mtd->block_isbad) {
 163                 ret = mtd->block_isbad(mtd, cxt->nextpage * OOPS_PAGE_SIZE);
 164                 if (!ret)
 165                         break;
 166                 if (ret < 0) {
 167                         printk(KERN_ERR "mtdoops: block_isbad failed, aborting\n");
 168                         return;
 169                 }
 170 badblock:
 171                 printk(KERN_WARNING "mtdoops: bad block at %08x\n",
 172                        cxt->nextpage * OOPS_PAGE_SIZE);
 173                 i++;
 174                 cxt->nextpage = cxt->nextpage + (mtd->erasesize / OOPS_PAGE_SIZE);
 175                 if (cxt->nextpage >= cxt->oops_pages)
 176                         cxt->nextpage = 0;
 177                 if (i == cxt->oops_pages / (mtd->erasesize / OOPS_PAGE_SIZE)) {
 178                         printk(KERN_ERR "mtdoops: all blocks bad!\n");
 179                         return;
 180                 }
 181         }
 182
 183         for (j = 0, ret = -1; (j < 3) && (ret < 0); j++)
 184                 ret = mtdoops_erase_block(cxt, cxt->nextpage * OOPS_PAGE_SIZE);
 185
 186         if (ret >= 0) {
 187                 printk(KERN_DEBUG "mtdoops: ready %d, %d\n",
 188                        cxt->nextpage, cxt->nextcount);
 189                 cxt->ready = 1;
 190                 return;
 191         }
 192
 193         if (mtd->block_markbad && ret == -EIO) {
 194                 ret = mtd->block_markbad(mtd, cxt->nextpage * OOPS_PAGE_SIZE);
 195                 if (ret < 0) {
 196                         printk(KERN_ERR "mtdoops: block_markbad failed, aborting\n");
 197                         return;
 198                 }
 199         }
 200         goto badblock;
 201 }
 202
 203 static void mtdoops_write(struct mtdoops_context *cxt, int panic)
 204 {
 205         struct mtd_info *mtd = cxt->mtd;
 206         size_t retlen;
 207         int ret;
 208
 209         if (cxt->writecount < OOPS_PAGE_SIZE)
 210                 memset(cxt->oops_buf + cxt->writecount, 0xff,
 211                                         OOPS_PAGE_SIZE - cxt->writecount);
 212
 213         if (panic)
 214                 ret = mtd->panic_write(mtd, cxt->nextpage * OOPS_PAGE_SIZE,
 215                                         OOPS_PAGE_SIZE, &retlen, cxt->oops_buf);
 216         else
 217                 ret = mtd->write(mtd, cxt->nextpage * OOPS_PAGE_SIZE,
 218                                         OOPS_PAGE_SIZE, &retlen, cxt->oops_buf);
 219
 220         cxt->writecount = 0;
 221
 222         if (retlen != OOPS_PAGE_SIZE || ret < 0)
 223                 printk(KERN_ERR "mtdoops: write failure at %d (%td of %d written), error %d\n",
 224                        cxt->nextpage * OOPS_PAGE_SIZE, retlen, OOPS_PAGE_SIZE, ret);
 225         mark_page_used(cxt, cxt->nextpage);
 226
 227         mtdoops_inc_counter(cxt);
 228 }
 229
 230
 231 static void mtdoops_workfunc_write(struct work_struct *work)
 232 {
 233         struct mtdoops_context *cxt =
 234                         container_of(work, struct mtdoops_context, work_write);
 235
 236         mtdoops_write(cxt, 0);
 237 }
 238
 239 static void find_next_position(struct mtdoops_context *cxt)
 240 {
 241         struct mtd_info *mtd = cxt->mtd;
 242         int ret, page, maxpos = 0;
 243         u32 count[2], maxcount = 0xffffffff;
 244         size_t retlen;
 245
 246         for (page = 0; page < cxt->oops_pages; page++) {
 247                 /* Assume the page is used */
 248                 mark_page_used(cxt, page);
 249                 ret = mtd->read(mtd, page * OOPS_PAGE_SIZE, 8, &retlen, (u_char *) &count[0]);
 250                 if (retlen != 8 || (ret < 0 && ret != -EUCLEAN)) {
 251                         printk(KERN_ERR "mtdoops: read failure at %d (%td of 8 read), err %d\n",
 252                                page * OOPS_PAGE_SIZE, retlen, ret);
 253                         continue;
 254                 }
 255
 256                 if (count[0] == 0xffffffff && count[1] == 0xffffffff)
 257                         mark_page_unused(cxt, page);
 258                 if (count[1] != MTDOOPS_KERNMSG_MAGIC)
 259                         continue;
 260                 if (count[0] == 0xffffffff)
 261                         continue;
 262                 if (maxcount == 0xffffffff) {
 263                         maxcount = count[0];
 264                         maxpos = page;
 265                 } else if (count[0] < 0x40000000 && maxcount > 0xc0000000) {
 266                         maxcount = count[0];
 267                         maxpos = page;
 268                 } else if (count[0] > maxcount && count[0] < 0xc0000000) {
 269                         maxcount = count[0];
 270                         maxpos = page;
 271                 } else if (count[0] > maxcount && count[0] > 0xc0000000
 272                                         && maxcount > 0x80000000) {
 273                         maxcount = count[0];
 274                         maxpos = page;
 275                 }
 276         }
 277         if (maxcount == 0xffffffff) {
 278                 cxt->nextpage = 0;
 279                 cxt->nextcount = 1;
 280                 schedule_work(&cxt->work_erase);
 281                 return;
 282         }
 283
 284         cxt->nextpage = maxpos;
 285         cxt->nextcount = maxcount;
 286
 287         mtdoops_inc_counter(cxt);
 288 }
 289
 290
 291 static void mtdoops_notify_add(struct mtd_info *mtd)
 292 {
 293         struct mtdoops_context *cxt = &oops_cxt;
 294         u64 mtdoops_pages = mtd->size;
 295
 296         do_div(mtdoops_pages, OOPS_PAGE_SIZE);
 297
 298         if (cxt->name && !strcmp(mtd->name, cxt->name))
 299                 cxt->mtd_index = mtd->index;
 300
 301         if (mtd->index != cxt->mtd_index || cxt->mtd_index < 0)
 302                 return;
 303
 304         if (mtd->size < mtd->erasesize * 2) {
 305                 printk(KERN_ERR "mtdoops: MTD partition %d not big enough for mtdoops\n",
 306                        mtd->index);
 307                 return;
 308         }
 309
 310         if (mtd->erasesize < OOPS_PAGE_SIZE) {
 311                 printk(KERN_ERR "mtdoops: eraseblock size of MTD partition %d too small\n",
 312                        mtd->index);
 313                 return;
 314         }
 315
 316         if (mtd->size > MTDOOPS_MAX_MTD_SIZE) {
 317                 printk(KERN_ERR "mtdoops: mtd%d is too large (limit is %d MiB)\n",
 318                        mtd->index, MTDOOPS_MAX_MTD_SIZE / 1024 / 1024);
 319                 return;
 320         }
 321
 322         /* oops_page_used is a bit field */
 323         cxt->oops_page_used = vmalloc(DIV_ROUND_UP(mtdoops_pages,
 324                         BITS_PER_LONG));
 325         if (!cxt->oops_page_used) {
 326                 printk(KERN_ERR "Could not allocate page array\n");
 327                 return;
 328         }
 329
 330         cxt->mtd = mtd;
 331         cxt->oops_pages = (int)mtd->size / OOPS_PAGE_SIZE;
 332         find_next_position(cxt);
 333         printk(KERN_INFO "mtdoops: Attached to MTD device %d\n", mtd->index);
 334 }
 335
 336 static void mtdoops_notify_remove(struct mtd_info *mtd)
 337 {
 338         struct mtdoops_context *cxt = &oops_cxt;
 339
 340         if (mtd->index != cxt->mtd_index || cxt->mtd_index < 0)
 341                 return;
 342
 343         cxt->mtd = NULL;
 344         flush_scheduled_work();
 345 }
 346
 347 static void mtdoops_console_sync(void)
 348 {
 349         struct mtdoops_context *cxt = &oops_cxt;
 350         struct mtd_info *mtd = cxt->mtd;
 351         unsigned long flags;
 352
 353         if (!cxt->ready || !mtd || cxt->writecount == 0)
 354                 return;
 355
 356         /*
 357          *  Once ready is 0 and we've held the lock no further writes to the
 358          *  buffer will happen
 359          */
 360         spin_lock_irqsave(&cxt->writecount_lock, flags);
 361         if (!cxt->ready) {
 362                 spin_unlock_irqrestore(&cxt->writecount_lock, flags);
 363                 return;
 364         }
 365         cxt->ready = 0;
 366         spin_unlock_irqrestore(&cxt->writecount_lock, flags);
 367
 368         if (mtd->panic_write && in_interrupt())
 369                 /* Interrupt context, we're going to panic so try and log */
 370                 mtdoops_write(cxt, 1);
 371         else
 372                 schedule_work(&cxt->work_write);
 373 }
 374
 375 static void
 376 mtdoops_console_write(struct console *co, const char *s, unsigned int count)
 377 {
 378         struct mtdoops_context *cxt = co->data;
 379         struct mtd_info *mtd = cxt->mtd;
 380         unsigned long flags;
 381
 382         if (!oops_in_progress) {
 383                 mtdoops_console_sync();
 384                 return;
 385         }
 386
 387         if (!cxt->ready || !mtd)
 388                 return;
 389
 390         /* Locking on writecount ensures sequential writes to the buffer */
 391         spin_lock_irqsave(&cxt->writecount_lock, flags);
 392
 393         /* Check ready status didn't change whilst waiting for the lock */
 394         if (!cxt->ready) {
 395                 spin_unlock_irqrestore(&cxt->writecount_lock, flags);
 396                 return;
 397         }
 398
 399         if (cxt->writecount == 0) {
 400                 u32 *stamp = cxt->oops_buf;
 401                 *stamp++ = cxt->nextcount;
 402                 *stamp = MTDOOPS_KERNMSG_MAGIC;
 403                 cxt->writecount = 8;
 404         }
 405
 406         if (count + cxt->writecount > OOPS_PAGE_SIZE)
 407                 count = OOPS_PAGE_SIZE - cxt->writecount;
 408
 409         memcpy(cxt->oops_buf + cxt->writecount, s, count);
 410         cxt->writecount += count;
 411
 412         spin_unlock_irqrestore(&cxt->writecount_lock, flags);
 413
 414         if (cxt->writecount == OOPS_PAGE_SIZE)
 415                 mtdoops_console_sync();
 416 }
 417
 418 static int __init mtdoops_console_setup(struct console *co, char *options)
 419 {
 420         struct mtdoops_context *cxt = co->data;
 421
 422         if (cxt->mtd_index != -1 || cxt->name)
 423                 return -EBUSY;
 424         if (options) {
 425                 cxt->name = kstrdup(options, GFP_KERNEL);
 426                 return 0;
 427         }
 428         if (co->index == -1)
 429                 return -EINVAL;
 430
 431         cxt->mtd_index = co->index;
 432         return 0;
 433 }
 434
 435 static struct mtd_notifier mtdoops_notifier = {
 436         .add    = mtdoops_notify_add,
 437         .remove = mtdoops_notify_remove,
 438 };
 439
 440 static struct console mtdoops_console = {
 441         .name           = "ttyMTD",
 442         .write          = mtdoops_console_write,
 443         .setup          = mtdoops_console_setup,
 444         .unblank        = mtdoops_console_sync,
 445         .index          = -1,
 446         .data           = &oops_cxt,
 447 };
 448
 449 static int __init mtdoops_console_init(void)
 450 {
 451         struct mtdoops_context *cxt = &oops_cxt;
 452
 453         cxt->mtd_index = -1;
 454         cxt->oops_buf = vmalloc(OOPS_PAGE_SIZE);
 455         if (!cxt->oops_buf) {
 456                 printk(KERN_ERR "mtdoops: failed to allocate buffer workspace\n");
 457                 return -ENOMEM;
 458         }
 459
 460         spin_lock_init(&cxt->writecount_lock);
 461         INIT_WORK(&cxt->work_erase, mtdoops_workfunc_erase);
 462         INIT_WORK(&cxt->work_write, mtdoops_workfunc_write);
 463
 464         register_console(&mtdoops_console);
 465         register_mtd_user(&mtdoops_notifier);
 466         return 0;
 467 }
 468
 469 static void __exit mtdoops_console_exit(void)
 470 {
 471         struct mtdoops_context *cxt = &oops_cxt;
 472
 473         unregister_mtd_user(&mtdoops_notifier);
 474         unregister_console(&mtdoops_console);
 475         kfree(cxt->name);
 476         vfree(cxt->oops_buf);
 477         vfree(cxt->oops_page_used);
 478 }
 479
 480
 481 subsys_initcall(mtdoops_console_init);
 482 module_exit(mtdoops_console_exit);
 483
 484 MODULE_LICENSE("GPL");
 485 MODULE_AUTHOR("Richard Purdie <rpurdie@openedhand.com>");
 486 MODULE_DESCRIPTION("MTD Oops/Panic console logger/driver");