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