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 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
  48         void *oops_buf;
  49
  50         /* writecount and disabling ready are spin lock protected */
  51         spinlock_t writecount_lock;
  52         int ready;
  53         int writecount;
  54 } oops_cxt;
  55
  56 static void mtdoops_erase_callback(struct erase_info *done)
  57 {
  58         wait_queue_head_t *wait_q = (wait_queue_head_t *)done->priv;
  59         wake_up(wait_q);
  60 }
  61
  62 static int mtdoops_erase_block(struct mtd_info *mtd, int offset)
  63 {
  64         struct erase_info erase;
  65         DECLARE_WAITQUEUE(wait, current);
  66         wait_queue_head_t wait_q;
  67         int ret;
  68
  69         init_waitqueue_head(&wait_q);
  70         erase.mtd = mtd;
  71         erase.callback = mtdoops_erase_callback;
  72         erase.addr = offset;
  73         erase.len = mtd->erasesize;
  74         erase.priv = (u_long)&wait_q;
  75
  76         set_current_state(TASK_INTERRUPTIBLE);
  77         add_wait_queue(&wait_q, &wait);
  78
  79         ret = mtd->erase(mtd, &erase);
  80         if (ret) {
  81                 set_current_state(TASK_RUNNING);
  82                 remove_wait_queue(&wait_q, &wait);
  83                 printk (KERN_WARNING "mtdoops: erase of region [0x%llx, 0x%llx] "
  84                                      "on \"%s\" failed\n",
  85                         (unsigned long long)erase.addr, (unsigned long long)erase.len, mtd->name);
  86                 return ret;
  87         }
  88
  89         schedule();  /* Wait for erase to finish. */
  90         remove_wait_queue(&wait_q, &wait);
  91
  92         return 0;
  93 }
  94
  95 static void mtdoops_inc_counter(struct mtdoops_context *cxt)
  96 {
  97         struct mtd_info *mtd = cxt->mtd;
  98         size_t retlen;
  99         u32 count;
 100         int ret;
 101
 102         cxt->nextpage++;
 103         if (cxt->nextpage >= cxt->oops_pages)
 104                 cxt->nextpage = 0;
 105         cxt->nextcount++;
 106         if (cxt->nextcount == 0xffffffff)
 107                 cxt->nextcount = 0;
 108
 109         ret = mtd->read(mtd, cxt->nextpage * OOPS_PAGE_SIZE, 4,
 110                         &retlen, (u_char *) &count);
 111         if ((retlen != 4) || ((ret < 0) && (ret != -EUCLEAN))) {
 112                 printk(KERN_ERR "mtdoops: Read failure at %d (%td of 4 read)"
 113                                 ", err %d.\n", cxt->nextpage * OOPS_PAGE_SIZE,
 114                                 retlen, ret);
 115                 schedule_work(&cxt->work_erase);
 116                 return;
 117         }
 118
 119         /* See if we need to erase the next block */
 120         if (count != 0xffffffff) {
 121                 schedule_work(&cxt->work_erase);
 122                 return;
 123         }
 124
 125         printk(KERN_DEBUG "mtdoops: Ready %d, %d (no erase)\n",
 126                         cxt->nextpage, cxt->nextcount);
 127         cxt->ready = 1;
 128 }
 129
 130 /* Scheduled work - when we can't proceed without erasing a block */
 131 static void mtdoops_workfunc_erase(struct work_struct *work)
 132 {
 133         struct mtdoops_context *cxt =
 134                         container_of(work, struct mtdoops_context, work_erase);
 135         struct mtd_info *mtd = cxt->mtd;
 136         int i = 0, j, ret, mod;
 137
 138         /* We were unregistered */
 139         if (!mtd)
 140                 return;
 141
 142         mod = (cxt->nextpage * OOPS_PAGE_SIZE) % mtd->erasesize;
 143         if (mod != 0) {
 144                 cxt->nextpage = cxt->nextpage + ((mtd->erasesize - mod) / OOPS_PAGE_SIZE);
 145                 if (cxt->nextpage >= cxt->oops_pages)
 146                         cxt->nextpage = 0;
 147         }
 148
 149         while (mtd->block_isbad) {
 150                 ret = mtd->block_isbad(mtd, cxt->nextpage * OOPS_PAGE_SIZE);
 151                 if (!ret)
 152                         break;
 153                 if (ret < 0) {
 154                         printk(KERN_ERR "mtdoops: block_isbad failed, aborting.\n");
 155                         return;
 156                 }
 157 badblock:
 158                 printk(KERN_WARNING "mtdoops: Bad block at %08x\n",
 159                                 cxt->nextpage * OOPS_PAGE_SIZE);
 160                 i++;
 161                 cxt->nextpage = cxt->nextpage + (mtd->erasesize / OOPS_PAGE_SIZE);
 162                 if (cxt->nextpage >= cxt->oops_pages)
 163                         cxt->nextpage = 0;
 164                 if (i == (cxt->oops_pages / (mtd->erasesize / OOPS_PAGE_SIZE))) {
 165                         printk(KERN_ERR "mtdoops: All blocks bad!\n");
 166                         return;
 167                 }
 168         }
 169
 170         for (j = 0, ret = -1; (j < 3) && (ret < 0); j++)
 171                 ret = mtdoops_erase_block(mtd, cxt->nextpage * OOPS_PAGE_SIZE);
 172
 173         if (ret >= 0) {
 174                 printk(KERN_DEBUG "mtdoops: Ready %d, %d \n", cxt->nextpage, cxt->nextcount);
 175                 cxt->ready = 1;
 176                 return;
 177         }
 178
 179         if (mtd->block_markbad && (ret == -EIO)) {
 180                 ret = mtd->block_markbad(mtd, cxt->nextpage * OOPS_PAGE_SIZE);
 181                 if (ret < 0) {
 182                         printk(KERN_ERR "mtdoops: block_markbad failed, aborting.\n");
 183                         return;
 184                 }
 185         }
 186         goto badblock;
 187 }
 188
 189 static void mtdoops_write(struct mtdoops_context *cxt, int panic)
 190 {
 191         struct mtd_info *mtd = cxt->mtd;
 192         size_t retlen;
 193         int ret;
 194
 195         if (cxt->writecount < OOPS_PAGE_SIZE)
 196                 memset(cxt->oops_buf + cxt->writecount, 0xff,
 197                                         OOPS_PAGE_SIZE - cxt->writecount);
 198
 199         if (panic)
 200                 ret = mtd->panic_write(mtd, cxt->nextpage * OOPS_PAGE_SIZE,
 201                                         OOPS_PAGE_SIZE, &retlen, cxt->oops_buf);
 202         else
 203                 ret = mtd->write(mtd, cxt->nextpage * OOPS_PAGE_SIZE,
 204                                         OOPS_PAGE_SIZE, &retlen, cxt->oops_buf);
 205
 206         cxt->writecount = 0;
 207
 208         if ((retlen != OOPS_PAGE_SIZE) || (ret < 0))
 209                 printk(KERN_ERR "mtdoops: Write failure at %d (%td of %d written), err %d.\n",
 210                         cxt->nextpage * OOPS_PAGE_SIZE, retlen, OOPS_PAGE_SIZE, ret);
 211
 212         mtdoops_inc_counter(cxt);
 213 }
 214
 215
 216 static void mtdoops_workfunc_write(struct work_struct *work)
 217 {
 218         struct mtdoops_context *cxt =
 219                         container_of(work, struct mtdoops_context, work_write);
 220
 221         mtdoops_write(cxt, 0);
 222 }
 223
 224 static void find_next_position(struct mtdoops_context *cxt)
 225 {
 226         struct mtd_info *mtd = cxt->mtd;
 227         int ret, page, maxpos = 0;
 228         u32 count[2], maxcount = 0xffffffff;
 229         size_t retlen;
 230
 231         for (page = 0; page < cxt->oops_pages; page++) {
 232                 ret = mtd->read(mtd, page * OOPS_PAGE_SIZE, 8, &retlen, (u_char *) &count[0]);
 233                 if ((retlen != 8) || ((ret < 0) && (ret != -EUCLEAN))) {
 234                         printk(KERN_ERR "mtdoops: Read failure at %d (%td of 8 read)"
 235                                 ", err %d.\n", page * OOPS_PAGE_SIZE, retlen, ret);
 236                         continue;
 237                 }
 238
 239                 if (count[1] != MTDOOPS_KERNMSG_MAGIC)
 240                         continue;
 241                 if (count[0] == 0xffffffff)
 242                         continue;
 243                 if (maxcount == 0xffffffff) {
 244                         maxcount = count[0];
 245                         maxpos = page;
 246                 } else if ((count[0] < 0x40000000) && (maxcount > 0xc0000000)) {
 247                         maxcount = count[0];
 248                         maxpos = page;
 249                 } else if ((count[0] > maxcount) && (count[0] < 0xc0000000)) {
 250                         maxcount = count[0];
 251                         maxpos = page;
 252                 } else if ((count[0] > maxcount) && (count[0] > 0xc0000000)
 253                                         && (maxcount > 0x80000000)) {
 254                         maxcount = count[0];
 255                         maxpos = page;
 256                 }
 257         }
 258         if (maxcount == 0xffffffff) {
 259                 cxt->nextpage = 0;
 260                 cxt->nextcount = 1;
 261                 schedule_work(&cxt->work_erase);
 262                 return;
 263         }
 264
 265         cxt->nextpage = maxpos;
 266         cxt->nextcount = maxcount;
 267
 268         mtdoops_inc_counter(cxt);
 269 }
 270
 271
 272 static void mtdoops_notify_add(struct mtd_info *mtd)
 273 {
 274         struct mtdoops_context *cxt = &oops_cxt;
 275
 276         if ((mtd->index != cxt->mtd_index) || cxt->mtd_index < 0)
 277                 return;
 278
 279         if (mtd->size < (mtd->erasesize * 2)) {
 280                 printk(KERN_ERR "MTD partition %d not big enough for mtdoops\n",
 281                                 mtd->index);
 282                 return;
 283         }
 284
 285         if (mtd->erasesize < OOPS_PAGE_SIZE) {
 286                 printk(KERN_ERR "Eraseblock size of MTD partition %d too small\n",
 287                                 mtd->index);
 288                 return;
 289         }
 290
 291         cxt->mtd = mtd;
 292         if (mtd->size > INT_MAX)
 293                 cxt->oops_pages = INT_MAX / OOPS_PAGE_SIZE;
 294         else
 295                 cxt->oops_pages = (int)mtd->size / OOPS_PAGE_SIZE;
 296
 297         find_next_position(cxt);
 298
 299         printk(KERN_INFO "mtdoops: Attached to MTD device %d\n", mtd->index);
 300 }
 301
 302 static void mtdoops_notify_remove(struct mtd_info *mtd)
 303 {
 304         struct mtdoops_context *cxt = &oops_cxt;
 305
 306         if ((mtd->index != cxt->mtd_index) || cxt->mtd_index < 0)
 307                 return;
 308
 309         cxt->mtd = NULL;
 310         flush_scheduled_work();
 311 }
 312
 313 static void mtdoops_console_sync(void)
 314 {
 315         struct mtdoops_context *cxt = &oops_cxt;
 316         struct mtd_info *mtd = cxt->mtd;
 317         unsigned long flags;
 318
 319         if (!cxt->ready || !mtd || cxt->writecount == 0)
 320                 return;
 321
 322         /*
 323          *  Once ready is 0 and we've held the lock no further writes to the
 324          *  buffer will happen
 325          */
 326         spin_lock_irqsave(&cxt->writecount_lock, flags);
 327         if (!cxt->ready) {
 328                 spin_unlock_irqrestore(&cxt->writecount_lock, flags);
 329                 return;
 330         }
 331         cxt->ready = 0;
 332         spin_unlock_irqrestore(&cxt->writecount_lock, flags);
 333
 334         if (mtd->panic_write && in_interrupt())
 335                 /* Interrupt context, we're going to panic so try and log */
 336                 mtdoops_write(cxt, 1);
 337         else
 338                 schedule_work(&cxt->work_write);
 339 }
 340
 341 static void
 342 mtdoops_console_write(struct console *co, const char *s, unsigned int count)
 343 {
 344         struct mtdoops_context *cxt = co->data;
 345         struct mtd_info *mtd = cxt->mtd;
 346         unsigned long flags;
 347
 348         if (!oops_in_progress) {
 349                 mtdoops_console_sync();
 350                 return;
 351         }
 352
 353         if (!cxt->ready || !mtd)
 354                 return;
 355
 356         /* Locking on writecount ensures sequential writes to the buffer */
 357         spin_lock_irqsave(&cxt->writecount_lock, flags);
 358
 359         /* Check ready status didn't change whilst waiting for the lock */
 360         if (!cxt->ready)
 361                 return;
 362
 363         if (cxt->writecount == 0) {
 364                 u32 *stamp = cxt->oops_buf;
 365                 *stamp++ = cxt->nextcount;
 366                 *stamp = MTDOOPS_KERNMSG_MAGIC;
 367                 cxt->writecount = 8;
 368         }
 369
 370         if ((count + cxt->writecount) > OOPS_PAGE_SIZE)
 371                 count = OOPS_PAGE_SIZE - cxt->writecount;
 372
 373         memcpy(cxt->oops_buf + cxt->writecount, s, count);
 374         cxt->writecount += count;
 375
 376         spin_unlock_irqrestore(&cxt->writecount_lock, flags);
 377
 378         if (cxt->writecount == OOPS_PAGE_SIZE)
 379                 mtdoops_console_sync();
 380 }
 381
 382 static int __init mtdoops_console_setup(struct console *co, char *options)
 383 {
 384         struct mtdoops_context *cxt = co->data;
 385
 386         if (cxt->mtd_index != -1)
 387                 return -EBUSY;
 388         if (co->index == -1)
 389                 return -EINVAL;
 390
 391         cxt->mtd_index = co->index;
 392         return 0;
 393 }
 394
 395 static struct mtd_notifier mtdoops_notifier = {
 396         .add    = mtdoops_notify_add,
 397         .remove = mtdoops_notify_remove,
 398 };
 399
 400 static struct console mtdoops_console = {
 401         .name           = "ttyMTD",
 402         .write          = mtdoops_console_write,
 403         .setup          = mtdoops_console_setup,
 404         .unblank        = mtdoops_console_sync,
 405         .index          = -1,
 406         .data           = &oops_cxt,
 407 };
 408
 409 static int __init mtdoops_console_init(void)
 410 {
 411         struct mtdoops_context *cxt = &oops_cxt;
 412
 413         cxt->mtd_index = -1;
 414         cxt->oops_buf = vmalloc(OOPS_PAGE_SIZE);
 415
 416         if (!cxt->oops_buf) {
 417                 printk(KERN_ERR "Failed to allocate mtdoops buffer workspace\n");
 418                 return -ENOMEM;
 419         }
 420
 421         INIT_WORK(&cxt->work_erase, mtdoops_workfunc_erase);
 422         INIT_WORK(&cxt->work_write, mtdoops_workfunc_write);
 423
 424         register_console(&mtdoops_console);
 425         register_mtd_user(&mtdoops_notifier);
 426         return 0;
 427 }
 428
 429 static void __exit mtdoops_console_exit(void)
 430 {
 431         struct mtdoops_context *cxt = &oops_cxt;
 432
 433         unregister_mtd_user(&mtdoops_notifier);
 434         unregister_console(&mtdoops_console);
 435         vfree(cxt->oops_buf);
 436 }
 437
 438
 439 subsys_initcall(mtdoops_console_init);
 440 module_exit(mtdoops_console_exit);
 441
 442 MODULE_LICENSE("GPL");
 443 MODULE_AUTHOR("Richard Purdie <rpurdie@openedhand.com>");
 444 MODULE_DESCRIPTION("MTD Oops/Panic console logger/driver");