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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 /* Maximum MTD partition size */
  37 #define MTDOOPS_MAX_MTD_SIZE (8 * 1024 * 1024)
  38
  39 #define MTDOOPS_KERNMSG_MAGIC 0x5d005d00
  40
  41 static unsigned long record_size = 4096;
  42 module_param(record_size, ulong, 0400);
  43 MODULE_PARM_DESC(record_size,
  44                 "record size for MTD OOPS pages in bytes (default 4096)");
  45
  46 static struct mtdoops_context {
  47         int mtd_index;
  48         struct work_struct work_erase;
  49         struct work_struct work_write;
  50         struct mtd_info *mtd;
  51         int oops_pages;
  52         int nextpage;
  53         int nextcount;
  54         unsigned long *oops_page_used;
  55         char *name;
  56
  57         void *oops_buf;
  58
  59         /* writecount and disabling ready are spin lock protected */
  60         spinlock_t writecount_lock;
  61         int ready;
  62         int writecount;
  63 } oops_cxt;
  64
  65 static void mark_page_used(struct mtdoops_context *cxt, int page)
  66 {
  67         set_bit(page, cxt->oops_page_used);
  68 }
  69
  70 static void mark_page_unused(struct mtdoops_context *cxt, int page)
  71 {
  72         clear_bit(page, cxt->oops_page_used);
  73 }
  74
  75 static int page_is_used(struct mtdoops_context *cxt, int page)
  76 {
  77         return test_bit(page, cxt->oops_page_used);
  78 }
  79
  80 static void mtdoops_erase_callback(struct erase_info *done)
  81 {
  82         wait_queue_head_t *wait_q = (wait_queue_head_t *)done->priv;
  83         wake_up(wait_q);
  84 }
  85
  86 static int mtdoops_erase_block(struct mtdoops_context *cxt, int offset)
  87 {
  88         struct mtd_info *mtd = cxt->mtd;
  89         u32 start_page_offset = mtd_div_by_eb(offset, mtd) * mtd->erasesize;
  90         u32 start_page = start_page_offset / record_size;
  91         u32 erase_pages = mtd->erasesize / record_size;
  92         struct erase_info erase;
  93         DECLARE_WAITQUEUE(wait, current);
  94         wait_queue_head_t wait_q;
  95         int ret;
  96         int page;
  97
  98         init_waitqueue_head(&wait_q);
  99         erase.mtd = mtd;
 100         erase.callback = mtdoops_erase_callback;
 101         erase.addr = offset;
 102         erase.len = mtd->erasesize;
 103         erase.priv = (u_long)&wait_q;
 104
 105         set_current_state(TASK_INTERRUPTIBLE);
 106         add_wait_queue(&wait_q, &wait);
 107
 108         ret = mtd->erase(mtd, &erase);
 109         if (ret) {
 110                 set_current_state(TASK_RUNNING);
 111                 remove_wait_queue(&wait_q, &wait);
 112                 printk(KERN_WARNING "mtdoops: erase of region [0x%llx, 0x%llx] on \"%s\" failed\n",
 113                        (unsigned long long)erase.addr,
 114                        (unsigned long long)erase.len, mtd->name);
 115                 return ret;
 116         }
 117
 118         schedule();  /* Wait for erase to finish. */
 119         remove_wait_queue(&wait_q, &wait);
 120
 121         /* Mark pages as unused */
 122         for (page = start_page; page < start_page + erase_pages; page++)
 123                 mark_page_unused(cxt, page);
 124
 125         return 0;
 126 }
 127
 128 static void mtdoops_inc_counter(struct mtdoops_context *cxt)
 129 {
 130         cxt->nextpage++;
 131         if (cxt->nextpage >= cxt->oops_pages)
 132                 cxt->nextpage = 0;
 133         cxt->nextcount++;
 134         if (cxt->nextcount == 0xffffffff)
 135                 cxt->nextcount = 0;
 136
 137         if (page_is_used(cxt, cxt->nextpage)) {
 138                 schedule_work(&cxt->work_erase);
 139                 return;
 140         }
 141
 142         printk(KERN_DEBUG "mtdoops: ready %d, %d (no erase)\n",
 143                cxt->nextpage, cxt->nextcount);
 144         cxt->ready = 1;
 145 }
 146
 147 /* Scheduled work - when we can't proceed without erasing a block */
 148 static void mtdoops_workfunc_erase(struct work_struct *work)
 149 {
 150         struct mtdoops_context *cxt =
 151                         container_of(work, struct mtdoops_context, work_erase);
 152         struct mtd_info *mtd = cxt->mtd;
 153         int i = 0, j, ret, mod;
 154
 155         /* We were unregistered */
 156         if (!mtd)
 157                 return;
 158
 159         mod = (cxt->nextpage * record_size) % mtd->erasesize;
 160         if (mod != 0) {
 161                 cxt->nextpage = cxt->nextpage + ((mtd->erasesize - mod) / record_size);
 162                 if (cxt->nextpage >= cxt->oops_pages)
 163                         cxt->nextpage = 0;
 164         }
 165
 166         while (mtd->block_isbad) {
 167                 ret = mtd->block_isbad(mtd, cxt->nextpage * record_size);
 168                 if (!ret)
 169                         break;
 170                 if (ret < 0) {
 171                         printk(KERN_ERR "mtdoops: block_isbad failed, aborting\n");
 172                         return;
 173                 }
 174 badblock:
 175                 printk(KERN_WARNING "mtdoops: bad block at %08lx\n",
 176                        cxt->nextpage * record_size);
 177                 i++;
 178                 cxt->nextpage = cxt->nextpage + (mtd->erasesize / record_size);
 179                 if (cxt->nextpage >= cxt->oops_pages)
 180                         cxt->nextpage = 0;
 181                 if (i == cxt->oops_pages / (mtd->erasesize / record_size)) {
 182                         printk(KERN_ERR "mtdoops: all blocks bad!\n");
 183                         return;
 184                 }
 185         }
 186
 187         for (j = 0, ret = -1; (j < 3) && (ret < 0); j++)
 188                 ret = mtdoops_erase_block(cxt, cxt->nextpage * record_size);
 189
 190         if (ret >= 0) {
 191                 printk(KERN_DEBUG "mtdoops: ready %d, %d\n",
 192                        cxt->nextpage, cxt->nextcount);
 193                 cxt->ready = 1;
 194                 return;
 195         }
 196
 197         if (mtd->block_markbad && ret == -EIO) {
 198                 ret = mtd->block_markbad(mtd, cxt->nextpage * record_size);
 199                 if (ret < 0) {
 200                         printk(KERN_ERR "mtdoops: block_markbad failed, aborting\n");
 201                         return;
 202                 }
 203         }
 204         goto badblock;
 205 }
 206
 207 static void mtdoops_write(struct mtdoops_context *cxt, int panic)
 208 {
 209         struct mtd_info *mtd = cxt->mtd;
 210         size_t retlen;
 211         int ret;
 212
 213         if (cxt->writecount < record_size)
 214                 memset(cxt->oops_buf + cxt->writecount, 0xff,
 215                                         record_size - cxt->writecount);
 216
 217         if (panic)
 218                 ret = mtd->panic_write(mtd, cxt->nextpage * record_size,
 219                                         record_size, &retlen, cxt->oops_buf);
 220         else
 221                 ret = mtd->write(mtd, cxt->nextpage * record_size,
 222                                         record_size, &retlen, cxt->oops_buf);
 223
 224         cxt->writecount = 0;
 225
 226         if (retlen != record_size || ret < 0)
 227                 printk(KERN_ERR "mtdoops: write failure at %ld (%td of %ld written), error %d\n",
 228                        cxt->nextpage * record_size, retlen, record_size, ret);
 229         mark_page_used(cxt, cxt->nextpage);
 230
 231         mtdoops_inc_counter(cxt);
 232 }
 233
 234
 235 static void mtdoops_workfunc_write(struct work_struct *work)
 236 {
 237         struct mtdoops_context *cxt =
 238                         container_of(work, struct mtdoops_context, work_write);
 239
 240         mtdoops_write(cxt, 0);
 241 }
 242
 243 static void find_next_position(struct mtdoops_context *cxt)
 244 {
 245         struct mtd_info *mtd = cxt->mtd;
 246         int ret, page, maxpos = 0;
 247         u32 count[2], maxcount = 0xffffffff;
 248         size_t retlen;
 249
 250         for (page = 0; page < cxt->oops_pages; page++) {
 251                 /* Assume the page is used */
 252                 mark_page_used(cxt, page);
 253                 ret = mtd->read(mtd, page * record_size, 8, &retlen, (u_char *) &count[0]);
 254                 if (retlen != 8 || (ret < 0 && ret != -EUCLEAN)) {
 255                         printk(KERN_ERR "mtdoops: read failure at %ld (%td of 8 read), err %d\n",
 256                                page * record_size, retlen, ret);
 257                         continue;
 258                 }
 259
 260                 if (count[0] == 0xffffffff && count[1] == 0xffffffff)
 261                         mark_page_unused(cxt, page);
 262                 if (count[1] != MTDOOPS_KERNMSG_MAGIC)
 263                         continue;
 264                 if (count[0] == 0xffffffff)
 265                         continue;
 266                 if (maxcount == 0xffffffff) {
 267                         maxcount = count[0];
 268                         maxpos = page;
 269                 } else if (count[0] < 0x40000000 && maxcount > 0xc0000000) {
 270                         maxcount = count[0];
 271                         maxpos = page;
 272                 } else if (count[0] > maxcount && count[0] < 0xc0000000) {
 273                         maxcount = count[0];
 274                         maxpos = page;
 275                 } else if (count[0] > maxcount && count[0] > 0xc0000000
 276                                         && maxcount > 0x80000000) {
 277                         maxcount = count[0];
 278                         maxpos = page;
 279                 }
 280         }
 281         if (maxcount == 0xffffffff) {
 282                 cxt->nextpage = 0;
 283                 cxt->nextcount = 1;
 284                 schedule_work(&cxt->work_erase);
 285                 return;
 286         }
 287
 288         cxt->nextpage = maxpos;
 289         cxt->nextcount = maxcount;
 290
 291         mtdoops_inc_counter(cxt);
 292 }
 293
 294
 295 static void mtdoops_notify_add(struct mtd_info *mtd)
 296 {
 297         struct mtdoops_context *cxt = &oops_cxt;
 298         u64 mtdoops_pages = mtd->size;
 299
 300         do_div(mtdoops_pages, record_size);
 301
 302         if (cxt->name && !strcmp(mtd->name, cxt->name))
 303                 cxt->mtd_index = mtd->index;
 304
 305         if (mtd->index != cxt->mtd_index || cxt->mtd_index < 0)
 306                 return;
 307
 308         if (mtd->size < mtd->erasesize * 2) {
 309                 printk(KERN_ERR "mtdoops: MTD partition %d not big enough for mtdoops\n",
 310                        mtd->index);
 311                 return;
 312         }
 313
 314         if (mtd->erasesize < record_size) {
 315                 printk(KERN_ERR "mtdoops: eraseblock size of MTD partition %d too small\n",
 316                        mtd->index);
 317                 return;
 318         }
 319
 320         if (mtd->size > MTDOOPS_MAX_MTD_SIZE) {
 321                 printk(KERN_ERR "mtdoops: mtd%d is too large (limit is %d MiB)\n",
 322                        mtd->index, MTDOOPS_MAX_MTD_SIZE / 1024 / 1024);
 323                 return;
 324         }
 325
 326         /* oops_page_used is a bit field */
 327         cxt->oops_page_used = vmalloc(DIV_ROUND_UP(mtdoops_pages,
 328                         BITS_PER_LONG));
 329         if (!cxt->oops_page_used) {
 330                 printk(KERN_ERR "Could not allocate page array\n");
 331                 return;
 332         }
 333
 334         cxt->mtd = mtd;
 335         cxt->oops_pages = (int)mtd->size / record_size;
 336         find_next_position(cxt);
 337         printk(KERN_INFO "mtdoops: Attached to MTD device %d\n", mtd->index);
 338 }
 339
 340 static void mtdoops_notify_remove(struct mtd_info *mtd)
 341 {
 342         struct mtdoops_context *cxt = &oops_cxt;
 343
 344         if (mtd->index != cxt->mtd_index || cxt->mtd_index < 0)
 345                 return;
 346
 347         cxt->mtd = NULL;
 348         flush_scheduled_work();
 349 }
 350
 351 static void mtdoops_console_sync(void)
 352 {
 353         struct mtdoops_context *cxt = &oops_cxt;
 354         struct mtd_info *mtd = cxt->mtd;
 355         unsigned long flags;
 356
 357         if (!cxt->ready || !mtd || cxt->writecount == 0)
 358                 return;
 359
 360         /*
 361          *  Once ready is 0 and we've held the lock no further writes to the
 362          *  buffer will happen
 363          */
 364         spin_lock_irqsave(&cxt->writecount_lock, flags);
 365         if (!cxt->ready) {
 366                 spin_unlock_irqrestore(&cxt->writecount_lock, flags);
 367                 return;
 368         }
 369         cxt->ready = 0;
 370         spin_unlock_irqrestore(&cxt->writecount_lock, flags);
 371
 372         if (mtd->panic_write && in_interrupt())
 373                 /* Interrupt context, we're going to panic so try and log */
 374                 mtdoops_write(cxt, 1);
 375         else
 376                 schedule_work(&cxt->work_write);
 377 }
 378
 379 static void
 380 mtdoops_console_write(struct console *co, const char *s, unsigned int count)
 381 {
 382         struct mtdoops_context *cxt = co->data;
 383         struct mtd_info *mtd = cxt->mtd;
 384         unsigned long flags;
 385
 386         if (!oops_in_progress) {
 387                 mtdoops_console_sync();
 388                 return;
 389         }
 390
 391         if (!cxt->ready || !mtd)
 392                 return;
 393
 394         /* Locking on writecount ensures sequential writes to the buffer */
 395         spin_lock_irqsave(&cxt->writecount_lock, flags);
 396
 397         /* Check ready status didn't change whilst waiting for the lock */
 398         if (!cxt->ready) {
 399                 spin_unlock_irqrestore(&cxt->writecount_lock, flags);
 400                 return;
 401         }
 402
 403         if (cxt->writecount == 0) {
 404                 u32 *stamp = cxt->oops_buf;
 405                 *stamp++ = cxt->nextcount;
 406                 *stamp = MTDOOPS_KERNMSG_MAGIC;
 407                 cxt->writecount = 8;
 408         }
 409
 410         if (count + cxt->writecount > record_size)
 411                 count = record_size - cxt->writecount;
 412
 413         memcpy(cxt->oops_buf + cxt->writecount, s, count);
 414         cxt->writecount += count;
 415
 416         spin_unlock_irqrestore(&cxt->writecount_lock, flags);
 417
 418         if (cxt->writecount == record_size)
 419                 mtdoops_console_sync();
 420 }
 421
 422 static int __init mtdoops_console_setup(struct console *co, char *options)
 423 {
 424         struct mtdoops_context *cxt = co->data;
 425
 426         if (cxt->mtd_index != -1 || cxt->name)
 427                 return -EBUSY;
 428         if (options) {
 429                 cxt->name = kstrdup(options, GFP_KERNEL);
 430                 return 0;
 431         }
 432         if (co->index == -1)
 433                 return -EINVAL;
 434
 435         cxt->mtd_index = co->index;
 436         return 0;
 437 }
 438
 439 static struct mtd_notifier mtdoops_notifier = {
 440         .add    = mtdoops_notify_add,
 441         .remove = mtdoops_notify_remove,
 442 };
 443
 444 static struct console mtdoops_console = {
 445         .name           = "ttyMTD",
 446         .write          = mtdoops_console_write,
 447         .setup          = mtdoops_console_setup,
 448         .unblank        = mtdoops_console_sync,
 449         .index          = -1,
 450         .data           = &oops_cxt,
 451 };
 452
 453 static int __init mtdoops_console_init(void)
 454 {
 455         struct mtdoops_context *cxt = &oops_cxt;
 456
 457         if ((record_size & 4095) != 0) {
 458                 printk(KERN_ERR "mtdoops: record_size must be a multiple of 4096\n");
 459                 return -EINVAL;
 460         }
 461         if (record_size < 4096) {
 462                 printk(KERN_ERR "mtdoops: record_size must be over 4096 bytes\n");
 463                 return -EINVAL;
 464         }
 465         cxt->mtd_index = -1;
 466         cxt->oops_buf = vmalloc(record_size);
 467         if (!cxt->oops_buf) {
 468                 printk(KERN_ERR "mtdoops: failed to allocate buffer workspace\n");
 469                 return -ENOMEM;
 470         }
 471
 472         spin_lock_init(&cxt->writecount_lock);
 473         INIT_WORK(&cxt->work_erase, mtdoops_workfunc_erase);
 474         INIT_WORK(&cxt->work_write, mtdoops_workfunc_write);
 475
 476         register_console(&mtdoops_console);
 477         register_mtd_user(&mtdoops_notifier);
 478         return 0;
 479 }
 480
 481 static void __exit mtdoops_console_exit(void)
 482 {
 483         struct mtdoops_context *cxt = &oops_cxt;
 484
 485         unregister_mtd_user(&mtdoops_notifier);
 486         unregister_console(&mtdoops_console);
 487         kfree(cxt->name);
 488         vfree(cxt->oops_buf);
 489         vfree(cxt->oops_page_used);
 490 }
 491
 492
 493 subsys_initcall(mtdoops_console_init);
 494 module_exit(mtdoops_console_exit);
 495
 496 MODULE_LICENSE("GPL");
 497 MODULE_AUTHOR("Richard Purdie <rpurdie@openedhand.com>");
 498 MODULE_DESCRIPTION("MTD Oops/Panic console logger/driver");