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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         char *name;
  48
  49         void *oops_buf;
  50
  51         /* writecount and disabling ready are spin lock protected */
  52         spinlock_t writecount_lock;
  53         int ready;
  54         int writecount;
  55 } oops_cxt;
  56
  57 static void mtdoops_erase_callback(struct erase_info *done)
  58 {
  59         wait_queue_head_t *wait_q = (wait_queue_head_t *)done->priv;
  60         wake_up(wait_q);
  61 }
  62
  63 static int mtdoops_erase_block(struct mtd_info *mtd, int offset)
  64 {
  65         struct erase_info erase;
  66         DECLARE_WAITQUEUE(wait, current);
  67         wait_queue_head_t wait_q;
  68         int ret;
  69
  70         init_waitqueue_head(&wait_q);
  71         erase.mtd = mtd;
  72         erase.callback = mtdoops_erase_callback;
  73         erase.addr = offset;
  74         erase.len = mtd->erasesize;
  75         erase.priv = (u_long)&wait_q;
  76
  77         set_current_state(TASK_INTERRUPTIBLE);
  78         add_wait_queue(&wait_q, &wait);
  79
  80         ret = mtd->erase(mtd, &erase);
  81         if (ret) {
  82                 set_current_state(TASK_RUNNING);
  83                 remove_wait_queue(&wait_q, &wait);
  84                 printk (KERN_WARNING "mtdoops: erase of region [0x%llx, 0x%llx] "
  85                                      "on \"%s\" failed\n",
  86                         (unsigned long long)erase.addr, (unsigned long long)erase.len, mtd->name);
  87                 return ret;
  88         }
  89
  90         schedule();  /* Wait for erase to finish. */
  91         remove_wait_queue(&wait_q, &wait);
  92
  93         return 0;
  94 }
  95
  96 static void mtdoops_inc_counter(struct mtdoops_context *cxt)
  97 {
  98         struct mtd_info *mtd = cxt->mtd;
  99         size_t retlen;
 100         u32 count;
 101         int ret;
 102
 103         cxt->nextpage++;
 104         if (cxt->nextpage >= cxt->oops_pages)
 105                 cxt->nextpage = 0;
 106         cxt->nextcount++;
 107         if (cxt->nextcount == 0xffffffff)
 108                 cxt->nextcount = 0;
 109
 110         ret = mtd->read(mtd, cxt->nextpage * OOPS_PAGE_SIZE, 4,
 111                         &retlen, (u_char *) &count);
 112         if ((retlen != 4) || ((ret < 0) && (ret != -EUCLEAN))) {
 113                 printk(KERN_ERR "mtdoops: Read failure at %d (%td of 4 read)"
 114                                 ", err %d.\n", cxt->nextpage * OOPS_PAGE_SIZE,
 115                                 retlen, ret);
 116                 schedule_work(&cxt->work_erase);
 117                 return;
 118         }
 119
 120         /* See if we need to erase the next block */
 121         if (count != 0xffffffff) {
 122                 schedule_work(&cxt->work_erase);
 123                 return;
 124         }
 125
 126         printk(KERN_DEBUG "mtdoops: Ready %d, %d (no erase)\n",
 127                         cxt->nextpage, cxt->nextcount);
 128         cxt->ready = 1;
 129 }
 130
 131 /* Scheduled work - when we can't proceed without erasing a block */
 132 static void mtdoops_workfunc_erase(struct work_struct *work)
 133 {
 134         struct mtdoops_context *cxt =
 135                         container_of(work, struct mtdoops_context, work_erase);
 136         struct mtd_info *mtd = cxt->mtd;
 137         int i = 0, j, ret, mod;
 138
 139         /* We were unregistered */
 140         if (!mtd)
 141                 return;
 142
 143         mod = (cxt->nextpage * OOPS_PAGE_SIZE) % mtd->erasesize;
 144         if (mod != 0) {
 145                 cxt->nextpage = cxt->nextpage + ((mtd->erasesize - mod) / OOPS_PAGE_SIZE);
 146                 if (cxt->nextpage >= cxt->oops_pages)
 147                         cxt->nextpage = 0;
 148         }
 149
 150         while (mtd->block_isbad) {
 151                 ret = mtd->block_isbad(mtd, cxt->nextpage * OOPS_PAGE_SIZE);
 152                 if (!ret)
 153                         break;
 154                 if (ret < 0) {
 155                         printk(KERN_ERR "mtdoops: block_isbad failed, aborting.\n");
 156                         return;
 157                 }
 158 badblock:
 159                 printk(KERN_WARNING "mtdoops: Bad block at %08x\n",
 160                                 cxt->nextpage * OOPS_PAGE_SIZE);
 161                 i++;
 162                 cxt->nextpage = cxt->nextpage + (mtd->erasesize / OOPS_PAGE_SIZE);
 163                 if (cxt->nextpage >= cxt->oops_pages)
 164                         cxt->nextpage = 0;
 165                 if (i == (cxt->oops_pages / (mtd->erasesize / OOPS_PAGE_SIZE))) {
 166                         printk(KERN_ERR "mtdoops: All blocks bad!\n");
 167                         return;
 168                 }
 169         }
 170
 171         for (j = 0, ret = -1; (j < 3) && (ret < 0); j++)
 172                 ret = mtdoops_erase_block(mtd, cxt->nextpage * OOPS_PAGE_SIZE);
 173
 174         if (ret >= 0) {
 175                 printk(KERN_DEBUG "mtdoops: Ready %d, %d \n", cxt->nextpage, cxt->nextcount);
 176                 cxt->ready = 1;
 177                 return;
 178         }
 179
 180         if (mtd->block_markbad && (ret == -EIO)) {
 181                 ret = mtd->block_markbad(mtd, cxt->nextpage * OOPS_PAGE_SIZE);
 182                 if (ret < 0) {
 183                         printk(KERN_ERR "mtdoops: block_markbad failed, aborting.\n");
 184                         return;
 185                 }
 186         }
 187         goto badblock;
 188 }
 189
 190 static void mtdoops_write(struct mtdoops_context *cxt, int panic)
 191 {
 192         struct mtd_info *mtd = cxt->mtd;
 193         size_t retlen;
 194         int ret;
 195
 196         if (cxt->writecount < OOPS_PAGE_SIZE)
 197                 memset(cxt->oops_buf + cxt->writecount, 0xff,
 198                                         OOPS_PAGE_SIZE - cxt->writecount);
 199
 200         if (panic)
 201                 ret = mtd->panic_write(mtd, cxt->nextpage * OOPS_PAGE_SIZE,
 202                                         OOPS_PAGE_SIZE, &retlen, cxt->oops_buf);
 203         else
 204                 ret = mtd->write(mtd, cxt->nextpage * OOPS_PAGE_SIZE,
 205                                         OOPS_PAGE_SIZE, &retlen, cxt->oops_buf);
 206
 207         cxt->writecount = 0;
 208
 209         if ((retlen != OOPS_PAGE_SIZE) || (ret < 0))
 210                 printk(KERN_ERR "mtdoops: Write failure at %d (%td of %d written), err %d.\n",
 211                         cxt->nextpage * OOPS_PAGE_SIZE, retlen, OOPS_PAGE_SIZE, ret);
 212
 213         mtdoops_inc_counter(cxt);
 214 }
 215
 216
 217 static void mtdoops_workfunc_write(struct work_struct *work)
 218 {
 219         struct mtdoops_context *cxt =
 220                         container_of(work, struct mtdoops_context, work_write);
 221
 222         mtdoops_write(cxt, 0);
 223 }
 224
 225 static void find_next_position(struct mtdoops_context *cxt)
 226 {
 227         struct mtd_info *mtd = cxt->mtd;
 228         int ret, page, maxpos = 0;
 229         u32 count[2], maxcount = 0xffffffff;
 230         size_t retlen;
 231
 232         for (page = 0; page < cxt->oops_pages; page++) {
 233                 ret = mtd->read(mtd, page * OOPS_PAGE_SIZE, 8, &retlen, (u_char *) &count[0]);
 234                 if ((retlen != 8) || ((ret < 0) && (ret != -EUCLEAN))) {
 235                         printk(KERN_ERR "mtdoops: Read failure at %d (%td of 8 read)"
 236                                 ", err %d.\n", page * OOPS_PAGE_SIZE, retlen, ret);
 237                         continue;
 238                 }
 239
 240                 if (count[1] != MTDOOPS_KERNMSG_MAGIC)
 241                         continue;
 242                 if (count[0] == 0xffffffff)
 243                         continue;
 244                 if (maxcount == 0xffffffff) {
 245                         maxcount = count[0];
 246                         maxpos = page;
 247                 } else if ((count[0] < 0x40000000) && (maxcount > 0xc0000000)) {
 248                         maxcount = count[0];
 249                         maxpos = page;
 250                 } else if ((count[0] > maxcount) && (count[0] < 0xc0000000)) {
 251                         maxcount = count[0];
 252                         maxpos = page;
 253                 } else if ((count[0] > maxcount) && (count[0] > 0xc0000000)
 254                                         && (maxcount > 0x80000000)) {
 255                         maxcount = count[0];
 256                         maxpos = page;
 257                 }
 258         }
 259         if (maxcount == 0xffffffff) {
 260                 cxt->nextpage = 0;
 261                 cxt->nextcount = 1;
 262                 schedule_work(&cxt->work_erase);
 263                 return;
 264         }
 265
 266         cxt->nextpage = maxpos;
 267         cxt->nextcount = maxcount;
 268
 269         mtdoops_inc_counter(cxt);
 270 }
 271
 272
 273 static void mtdoops_notify_add(struct mtd_info *mtd)
 274 {
 275         struct mtdoops_context *cxt = &oops_cxt;
 276
 277         if (cxt->name && !strcmp(mtd->name, cxt->name))
 278                 cxt->mtd_index = mtd->index;
 279
 280         if ((mtd->index != cxt->mtd_index) || cxt->mtd_index < 0)
 281                 return;
 282
 283         if (mtd->size < (mtd->erasesize * 2)) {
 284                 printk(KERN_ERR "MTD partition %d not big enough for mtdoops\n",
 285                                 mtd->index);
 286                 return;
 287         }
 288
 289         if (mtd->erasesize < OOPS_PAGE_SIZE) {
 290                 printk(KERN_ERR "Eraseblock size of MTD partition %d too small\n",
 291                                 mtd->index);
 292                 return;
 293         }
 294
 295         cxt->mtd = mtd;
 296         if (mtd->size > INT_MAX)
 297                 cxt->oops_pages = INT_MAX / OOPS_PAGE_SIZE;
 298         else
 299                 cxt->oops_pages = (int)mtd->size / OOPS_PAGE_SIZE;
 300
 301         find_next_position(cxt);
 302
 303         printk(KERN_INFO "mtdoops: Attached to MTD device %d\n", mtd->index);
 304 }
 305
 306 static void mtdoops_notify_remove(struct mtd_info *mtd)
 307 {
 308         struct mtdoops_context *cxt = &oops_cxt;
 309
 310         if ((mtd->index != cxt->mtd_index) || cxt->mtd_index < 0)
 311                 return;
 312
 313         cxt->mtd = NULL;
 314         flush_scheduled_work();
 315 }
 316
 317 static void mtdoops_console_sync(void)
 318 {
 319         struct mtdoops_context *cxt = &oops_cxt;
 320         struct mtd_info *mtd = cxt->mtd;
 321         unsigned long flags;
 322
 323         if (!cxt->ready || !mtd || cxt->writecount == 0)
 324                 return;
 325
 326         /*
 327          *  Once ready is 0 and we've held the lock no further writes to the
 328          *  buffer will happen
 329          */
 330         spin_lock_irqsave(&cxt->writecount_lock, flags);
 331         if (!cxt->ready) {
 332                 spin_unlock_irqrestore(&cxt->writecount_lock, flags);
 333                 return;
 334         }
 335         cxt->ready = 0;
 336         spin_unlock_irqrestore(&cxt->writecount_lock, flags);
 337
 338         if (mtd->panic_write && in_interrupt())
 339                 /* Interrupt context, we're going to panic so try and log */
 340                 mtdoops_write(cxt, 1);
 341         else
 342                 schedule_work(&cxt->work_write);
 343 }
 344
 345 static void
 346 mtdoops_console_write(struct console *co, const char *s, unsigned int count)
 347 {
 348         struct mtdoops_context *cxt = co->data;
 349         struct mtd_info *mtd = cxt->mtd;
 350         unsigned long flags;
 351
 352         if (!oops_in_progress) {
 353                 mtdoops_console_sync();
 354                 return;
 355         }
 356
 357         if (!cxt->ready || !mtd)
 358                 return;
 359
 360         /* Locking on writecount ensures sequential writes to the buffer */
 361         spin_lock_irqsave(&cxt->writecount_lock, flags);
 362
 363         /* Check ready status didn't change whilst waiting for the lock */
 364         if (!cxt->ready) {
 365                 spin_unlock_irqrestore(&cxt->writecount_lock, flags);
 366                 return;
 367         }
 368
 369         if (cxt->writecount == 0) {
 370                 u32 *stamp = cxt->oops_buf;
 371                 *stamp++ = cxt->nextcount;
 372                 *stamp = MTDOOPS_KERNMSG_MAGIC;
 373                 cxt->writecount = 8;
 374         }
 375
 376         if ((count + cxt->writecount) > OOPS_PAGE_SIZE)
 377                 count = OOPS_PAGE_SIZE - cxt->writecount;
 378
 379         memcpy(cxt->oops_buf + cxt->writecount, s, count);
 380         cxt->writecount += count;
 381
 382         spin_unlock_irqrestore(&cxt->writecount_lock, flags);
 383
 384         if (cxt->writecount == OOPS_PAGE_SIZE)
 385                 mtdoops_console_sync();
 386 }
 387
 388 static int __init mtdoops_console_setup(struct console *co, char *options)
 389 {
 390         struct mtdoops_context *cxt = co->data;
 391
 392         if (cxt->mtd_index != -1 || cxt->name)
 393                 return -EBUSY;
 394         if (options) {
 395                 cxt->name = kstrdup(options, GFP_KERNEL);
 396                 return 0;
 397         }
 398         if (co->index == -1)
 399                 return -EINVAL;
 400
 401         cxt->mtd_index = co->index;
 402         return 0;
 403 }
 404
 405 static struct mtd_notifier mtdoops_notifier = {
 406         .add    = mtdoops_notify_add,
 407         .remove = mtdoops_notify_remove,
 408 };
 409
 410 static struct console mtdoops_console = {
 411         .name           = "ttyMTD",
 412         .write          = mtdoops_console_write,
 413         .setup          = mtdoops_console_setup,
 414         .unblank        = mtdoops_console_sync,
 415         .index          = -1,
 416         .data           = &oops_cxt,
 417 };
 418
 419 static int __init mtdoops_console_init(void)
 420 {
 421         struct mtdoops_context *cxt = &oops_cxt;
 422
 423         cxt->mtd_index = -1;
 424         cxt->oops_buf = vmalloc(OOPS_PAGE_SIZE);
 425         spin_lock_init(&cxt->writecount_lock);
 426
 427         if (!cxt->oops_buf) {
 428                 printk(KERN_ERR "Failed to allocate mtdoops buffer workspace\n");
 429                 return -ENOMEM;
 430         }
 431
 432         INIT_WORK(&cxt->work_erase, mtdoops_workfunc_erase);
 433         INIT_WORK(&cxt->work_write, mtdoops_workfunc_write);
 434
 435         register_console(&mtdoops_console);
 436         register_mtd_user(&mtdoops_notifier);
 437         return 0;
 438 }
 439
 440 static void __exit mtdoops_console_exit(void)
 441 {
 442         struct mtdoops_context *cxt = &oops_cxt;
 443
 444         unregister_mtd_user(&mtdoops_notifier);
 445         unregister_console(&mtdoops_console);
 446         kfree(cxt->name);
 447         vfree(cxt->oops_buf);
 448 }
 449
 450
 451 subsys_initcall(mtdoops_console_init);
 452 module_exit(mtdoops_console_exit);
 453
 454 MODULE_LICENSE("GPL");
 455 MODULE_AUTHOR("Richard Purdie <rpurdie@openedhand.com>");
 456 MODULE_DESCRIPTION("MTD Oops/Panic console logger/driver");