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 #define OOPS_PAGE_SIZE 4096
  37
  38 struct mtdoops_context {
  39         int mtd_index;
  40         struct work_struct work_erase;
  41         struct work_struct work_write;
  42         struct mtd_info *mtd;
  43         int oops_pages;
  44         int nextpage;
  45         int nextcount;
  46
  47         void *oops_buf;
  48
  49         /* writecount and disabling ready are spin lock protected */
  50         spinlock_t writecount_lock;
  51         int ready;
  52         int writecount;
  53 } oops_cxt;
  54
  55 static void mtdoops_erase_callback(struct erase_info *done)
  56 {
  57         wait_queue_head_t *wait_q = (wait_queue_head_t *)done->priv;
  58         wake_up(wait_q);
  59 }
  60
  61 static int mtdoops_erase_block(struct mtd_info *mtd, int offset)
  62 {
  63         struct erase_info erase;
  64         DECLARE_WAITQUEUE(wait, current);
  65         wait_queue_head_t wait_q;
  66         int ret;
  67
  68         init_waitqueue_head(&wait_q);
  69         erase.mtd = mtd;
  70         erase.callback = mtdoops_erase_callback;
  71         erase.addr = offset;
  72         erase.len = mtd->erasesize;
  73         erase.priv = (u_long)&wait_q;
  74
  75         set_current_state(TASK_INTERRUPTIBLE);
  76         add_wait_queue(&wait_q, &wait);
  77
  78         ret = mtd->erase(mtd, &erase);
  79         if (ret) {
  80                 set_current_state(TASK_RUNNING);
  81                 remove_wait_queue(&wait_q, &wait);
  82                 printk (KERN_WARNING "mtdoops: erase of region [0x%x, 0x%x] "
  83                                      "on \"%s\" failed\n",
  84                         erase.addr, erase.len, mtd->name);
  85                 return ret;
  86         }
  87
  88         schedule();  /* Wait for erase to finish. */
  89         remove_wait_queue(&wait_q, &wait);
  90
  91         return 0;
  92 }
  93
  94 static void mtdoops_inc_counter(struct mtdoops_context *cxt)
  95 {
  96         struct mtd_info *mtd = cxt->mtd;
  97         size_t retlen;
  98         u32 count;
  99         int ret;
 100
 101         cxt->nextpage++;
 102         if (cxt->nextpage > cxt->oops_pages)
 103                 cxt->nextpage = 0;
 104         cxt->nextcount++;
 105         if (cxt->nextcount == 0xffffffff)
 106                 cxt->nextcount = 0;
 107
 108         ret = mtd->read(mtd, cxt->nextpage * OOPS_PAGE_SIZE, 4,
 109                         &retlen, (u_char *) &count);
 110         if ((retlen != 4) || ((ret < 0) && (ret != -EUCLEAN))) {
 111                 printk(KERN_ERR "mtdoops: Read failure at %d (%td of 4 read)"
 112                                 ", err %d.\n", cxt->nextpage * OOPS_PAGE_SIZE,
 113                                 retlen, ret);
 114                 schedule_work(&cxt->work_erase);
 115                 return;
 116         }
 117
 118         /* See if we need to erase the next block */
 119         if (count != 0xffffffff) {
 120                 schedule_work(&cxt->work_erase);
 121                 return;
 122         }
 123
 124         printk(KERN_DEBUG "mtdoops: Ready %d, %d (no erase)\n",
 125                         cxt->nextpage, cxt->nextcount);
 126         cxt->ready = 1;
 127 }
 128
 129 /* Scheduled work - when we can't proceed without erasing a block */
 130 static void mtdoops_workfunc_erase(struct work_struct *work)
 131 {
 132         struct mtdoops_context *cxt =
 133                         container_of(work, struct mtdoops_context, work_erase);
 134         struct mtd_info *mtd = cxt->mtd;
 135         int i = 0, j, ret, mod;
 136
 137         /* We were unregistered */
 138         if (!mtd)
 139                 return;
 140
 141         mod = (cxt->nextpage * OOPS_PAGE_SIZE) % mtd->erasesize;
 142         if (mod != 0) {
 143                 cxt->nextpage = cxt->nextpage + ((mtd->erasesize - mod) / OOPS_PAGE_SIZE);
 144                 if (cxt->nextpage > cxt->oops_pages)
 145                         cxt->nextpage = 0;
 146         }
 147
 148         while (mtd->block_isbad) {
 149                 ret = mtd->block_isbad(mtd, cxt->nextpage * OOPS_PAGE_SIZE);
 150                 if (!ret)
 151                         break;
 152                 if (ret < 0) {
 153                         printk(KERN_ERR "mtdoops: block_isbad failed, aborting.\n");
 154                         return;
 155                 }
 156 badblock:
 157                 printk(KERN_WARNING "mtdoops: Bad block at %08x\n",
 158                                 cxt->nextpage * OOPS_PAGE_SIZE);
 159                 i++;
 160                 cxt->nextpage = cxt->nextpage + (mtd->erasesize / OOPS_PAGE_SIZE);
 161                 if (cxt->nextpage > cxt->oops_pages)
 162                         cxt->nextpage = 0;
 163                 if (i == (cxt->oops_pages / (mtd->erasesize / OOPS_PAGE_SIZE))) {
 164                         printk(KERN_ERR "mtdoops: All blocks bad!\n");
 165                         return;
 166                 }
 167         }
 168
 169         for (j = 0, ret = -1; (j < 3) && (ret < 0); j++)
 170                 ret = mtdoops_erase_block(mtd, cxt->nextpage * OOPS_PAGE_SIZE);
 171
 172         if (ret >= 0) {
 173                 printk(KERN_DEBUG "mtdoops: Ready %d, %d \n", cxt->nextpage, cxt->nextcount);
 174                 cxt->ready = 1;
 175                 return;
 176         }
 177
 178         if (mtd->block_markbad && (ret == -EIO)) {
 179                 ret = mtd->block_markbad(mtd, cxt->nextpage * OOPS_PAGE_SIZE);
 180                 if (ret < 0) {
 181                         printk(KERN_ERR "mtdoops: block_markbad failed, aborting.\n");
 182                         return;
 183                 }
 184         }
 185         goto badblock;
 186 }
 187
 188 static void mtdoops_write(struct mtdoops_context *cxt, int panic)
 189 {
 190         struct mtd_info *mtd = cxt->mtd;
 191         size_t retlen;
 192         int ret;
 193
 194         if (cxt->writecount < OOPS_PAGE_SIZE)
 195                 memset(cxt->oops_buf + cxt->writecount, 0xff,
 196                                         OOPS_PAGE_SIZE - cxt->writecount);
 197
 198         if (panic)
 199                 ret = mtd->panic_write(mtd, cxt->nextpage * OOPS_PAGE_SIZE,
 200                                         OOPS_PAGE_SIZE, &retlen, cxt->oops_buf);
 201         else
 202                 ret = mtd->write(mtd, cxt->nextpage * OOPS_PAGE_SIZE,
 203                                         OOPS_PAGE_SIZE, &retlen, cxt->oops_buf);
 204
 205         cxt->writecount = 0;
 206
 207         if ((retlen != OOPS_PAGE_SIZE) || (ret < 0))
 208                 printk(KERN_ERR "mtdoops: Write failure at %d (%td of %d written), err %d.\n",
 209                         cxt->nextpage * OOPS_PAGE_SIZE, retlen, OOPS_PAGE_SIZE, ret);
 210
 211         mtdoops_inc_counter(cxt);
 212 }
 213
 214
 215 static void mtdoops_workfunc_write(struct work_struct *work)
 216 {
 217         struct mtdoops_context *cxt =
 218                         container_of(work, struct mtdoops_context, work_write);
 219
 220         mtdoops_write(cxt, 0);
 221 }
 222
 223 static void find_next_position(struct mtdoops_context *cxt)
 224 {
 225         struct mtd_info *mtd = cxt->mtd;
 226         int ret, page, maxpos = 0;
 227         u32 count, maxcount = 0xffffffff;
 228         size_t retlen;
 229
 230         for (page = 0; page < cxt->oops_pages; page++) {
 231                 ret = mtd->read(mtd, page * OOPS_PAGE_SIZE, 4, &retlen, (u_char *) &count);
 232                 if ((retlen != 4) || ((ret < 0) && (ret != -EUCLEAN))) {
 233                         printk(KERN_ERR "mtdoops: Read failure at %d (%td of 4 read)"
 234                                 ", err %d.\n", page * OOPS_PAGE_SIZE, retlen, ret);
 235                         continue;
 236                 }
 237
 238                 if (count == 0xffffffff)
 239                         continue;
 240                 if (maxcount == 0xffffffff) {
 241                         maxcount = count;
 242                         maxpos = page;
 243                 } else if ((count < 0x40000000) && (maxcount > 0xc0000000)) {
 244                         maxcount = count;
 245                         maxpos = page;
 246                 } else if ((count > maxcount) && (count < 0xc0000000)) {
 247                         maxcount = count;
 248                         maxpos = page;
 249                 } else if ((count > maxcount) && (count > 0xc0000000)
 250                                         && (maxcount > 0x80000000)) {
 251                         maxcount = count;
 252                         maxpos = page;
 253                 }
 254         }
 255         if (maxcount == 0xffffffff) {
 256                 cxt->nextpage = 0;
 257                 cxt->nextcount = 1;
 258                 cxt->ready = 1;
 259                 printk(KERN_DEBUG "mtdoops: Ready %d, %d (first init)\n",
 260                                 cxt->nextpage, cxt->nextcount);
 261                 return;
 262         }
 263
 264         cxt->nextpage = maxpos;
 265         cxt->nextcount = maxcount;
 266
 267         mtdoops_inc_counter(cxt);
 268 }
 269
 270
 271 static void mtdoops_notify_add(struct mtd_info *mtd)
 272 {
 273         struct mtdoops_context *cxt = &oops_cxt;
 274
 275         if ((mtd->index != cxt->mtd_index) || cxt->mtd_index < 0)
 276                 return;
 277
 278         if (mtd->size < (mtd->erasesize * 2)) {
 279                 printk(KERN_ERR "MTD partition %d not big enough for mtdoops\n",
 280                                 mtd->index);
 281                 return;
 282         }
 283
 284         if (mtd->erasesize < OOPS_PAGE_SIZE) {
 285                 printk(KERN_ERR "Eraseblock size of MTD partition %d too small\n",
 286                                 mtd->index);
 287                 return;
 288         }
 289
 290         cxt->mtd = mtd;
 291         cxt->oops_pages = mtd->size / OOPS_PAGE_SIZE;
 292
 293         find_next_position(cxt);
 294
 295         printk(KERN_INFO "mtdoops: Attached to MTD device %d\n", mtd->index);
 296 }
 297
 298 static void mtdoops_notify_remove(struct mtd_info *mtd)
 299 {
 300         struct mtdoops_context *cxt = &oops_cxt;
 301
 302         if ((mtd->index != cxt->mtd_index) || cxt->mtd_index < 0)
 303                 return;
 304
 305         cxt->mtd = NULL;
 306         flush_scheduled_work();
 307 }
 308
 309 static void mtdoops_console_sync(void)
 310 {
 311         struct mtdoops_context *cxt = &oops_cxt;
 312         struct mtd_info *mtd = cxt->mtd;
 313         unsigned long flags;
 314
 315         if (!cxt->ready || !mtd || cxt->writecount == 0)
 316                 return;
 317
 318         /*
 319          *  Once ready is 0 and we've held the lock no further writes to the
 320          *  buffer will happen
 321          */
 322         spin_lock_irqsave(&cxt->writecount_lock, flags);
 323         if (!cxt->ready) {
 324                 spin_unlock_irqrestore(&cxt->writecount_lock, flags);
 325                 return;
 326         }
 327         cxt->ready = 0;
 328         spin_unlock_irqrestore(&cxt->writecount_lock, flags);
 329
 330         if (mtd->panic_write && in_interrupt())
 331                 /* Interrupt context, we're going to panic so try and log */
 332                 mtdoops_write(cxt, 1);
 333         else
 334                 schedule_work(&cxt->work_write);
 335 }
 336
 337 static void
 338 mtdoops_console_write(struct console *co, const char *s, unsigned int count)
 339 {
 340         struct mtdoops_context *cxt = co->data;
 341         struct mtd_info *mtd = cxt->mtd;
 342         unsigned long flags;
 343
 344         if (!oops_in_progress) {
 345                 mtdoops_console_sync();
 346                 return;
 347         }
 348
 349         if (!cxt->ready || !mtd)
 350                 return;
 351
 352         /* Locking on writecount ensures sequential writes to the buffer */
 353         spin_lock_irqsave(&cxt->writecount_lock, flags);
 354
 355         /* Check ready status didn't change whilst waiting for the lock */
 356         if (!cxt->ready)
 357                 return;
 358
 359         if (cxt->writecount == 0) {
 360                 u32 *stamp = cxt->oops_buf;
 361                 *stamp = cxt->nextcount;
 362                 cxt->writecount = 4;
 363         }
 364
 365         if ((count + cxt->writecount) > OOPS_PAGE_SIZE)
 366                 count = OOPS_PAGE_SIZE - cxt->writecount;
 367
 368         memcpy(cxt->oops_buf + cxt->writecount, s, count);
 369         cxt->writecount += count;
 370
 371         spin_unlock_irqrestore(&cxt->writecount_lock, flags);
 372
 373         if (cxt->writecount == OOPS_PAGE_SIZE)
 374                 mtdoops_console_sync();
 375 }
 376
 377 static int __init mtdoops_console_setup(struct console *co, char *options)
 378 {
 379         struct mtdoops_context *cxt = co->data;
 380
 381         if (cxt->mtd_index != -1)
 382                 return -EBUSY;
 383         if (co->index == -1)
 384                 return -EINVAL;
 385
 386         cxt->mtd_index = co->index;
 387         return 0;
 388 }
 389
 390 static struct mtd_notifier mtdoops_notifier = {
 391         .add    = mtdoops_notify_add,
 392         .remove = mtdoops_notify_remove,
 393 };
 394
 395 static struct console mtdoops_console = {
 396         .name           = "ttyMTD",
 397         .write          = mtdoops_console_write,
 398         .setup          = mtdoops_console_setup,
 399         .unblank        = mtdoops_console_sync,
 400         .index          = -1,
 401         .data           = &oops_cxt,
 402 };
 403
 404 static int __init mtdoops_console_init(void)
 405 {
 406         struct mtdoops_context *cxt = &oops_cxt;
 407
 408         cxt->mtd_index = -1;
 409         cxt->oops_buf = vmalloc(OOPS_PAGE_SIZE);
 410
 411         if (!cxt->oops_buf) {
 412                 printk(KERN_ERR "Failed to allocate mtdoops buffer workspace\n");
 413                 return -ENOMEM;
 414         }
 415
 416         INIT_WORK(&cxt->work_erase, mtdoops_workfunc_erase);
 417         INIT_WORK(&cxt->work_write, mtdoops_workfunc_write);
 418
 419         register_console(&mtdoops_console);
 420         register_mtd_user(&mtdoops_notifier);
 421         return 0;
 422 }
 423
 424 static void __exit mtdoops_console_exit(void)
 425 {
 426         struct mtdoops_context *cxt = &oops_cxt;
 427
 428         unregister_mtd_user(&mtdoops_notifier);
 429         unregister_console(&mtdoops_console);
 430         vfree(cxt->oops_buf);
 431 }
 432
 433
 434 subsys_initcall(mtdoops_console_init);
 435 module_exit(mtdoops_console_exit);
 436
 437 MODULE_LICENSE("GPL");
 438 MODULE_AUTHOR("Richard Purdie <rpurdie@openedhand.com>");
 439 MODULE_DESCRIPTION("MTD Oops/Panic console logger/driver");