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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/spinlock.h>
  32 #include <linux/mtd/mtd.h>
  33
  34 #define OOPS_PAGE_SIZE 4096
  35
  36 struct mtdoops_context {
  37         int mtd_index;
  38         struct work_struct work_erase;
  39         struct work_struct work_write;
  40         struct mtd_info *mtd;
  41         int oops_pages;
  42         int nextpage;
  43         int nextcount;
  44
  45         void *oops_buf;
  46
  47         /* writecount and disabling ready are spin lock protected */
  48         spinlock_t writecount_lock;
  49         int ready;
  50         int writecount;
  51 } oops_cxt;
  52
  53 static void mtdoops_erase_callback(struct erase_info *done)
  54 {
  55         wait_queue_head_t *wait_q = (wait_queue_head_t *)done->priv;
  56         wake_up(wait_q);
  57 }
  58
  59 static int mtdoops_erase_block(struct mtd_info *mtd, int offset)
  60 {
  61         struct erase_info erase;
  62         DECLARE_WAITQUEUE(wait, current);
  63         wait_queue_head_t wait_q;
  64         int ret;
  65
  66         init_waitqueue_head(&wait_q);
  67         erase.mtd = mtd;
  68         erase.callback = mtdoops_erase_callback;
  69         erase.addr = offset;
  70         erase.len = mtd->erasesize;
  71         erase.priv = (u_long)&wait_q;
  72
  73         set_current_state(TASK_INTERRUPTIBLE);
  74         add_wait_queue(&wait_q, &wait);
  75
  76         ret = mtd->erase(mtd, &erase);
  77         if (ret) {
  78                 set_current_state(TASK_RUNNING);
  79                 remove_wait_queue(&wait_q, &wait);
  80                 printk (KERN_WARNING "mtdoops: erase of region [0x%x, 0x%x] "
  81                                      "on \"%s\" failed\n",
  82                         erase.addr, erase.len, mtd->name);
  83                 return ret;
  84         }
  85
  86         schedule();  /* Wait for erase to finish. */
  87         remove_wait_queue(&wait_q, &wait);
  88
  89         return 0;
  90 }
  91
  92 static void mtdoops_inc_counter(struct mtdoops_context *cxt)
  93 {
  94         struct mtd_info *mtd = cxt->mtd;
  95         size_t retlen;
  96         u32 count;
  97         int ret;
  98
  99         cxt->nextpage++;
 100         if (cxt->nextpage > cxt->oops_pages)
 101                 cxt->nextpage = 0;
 102         cxt->nextcount++;
 103         if (cxt->nextcount == 0xffffffff)
 104                 cxt->nextcount = 0;
 105
 106         ret = mtd->read(mtd, cxt->nextpage * OOPS_PAGE_SIZE, 4,
 107                         &retlen, (u_char *) &count);
 108         if ((retlen != 4) || ((ret < 0) && (ret != -EUCLEAN))) {
 109                 printk(KERN_ERR "mtdoops: Read failure at %d (%td of 4 read)"
 110                                 ", err %d.\n", cxt->nextpage * OOPS_PAGE_SIZE,
 111                                 retlen, ret);
 112                 schedule_work(&cxt->work_erase);
 113                 return;
 114         }
 115
 116         /* See if we need to erase the next block */
 117         if (count != 0xffffffff) {
 118                 schedule_work(&cxt->work_erase);
 119                 return;
 120         }
 121
 122         printk(KERN_DEBUG "mtdoops: Ready %d, %d (no erase)\n",
 123                         cxt->nextpage, cxt->nextcount);
 124         cxt->ready = 1;
 125 }
 126
 127 /* Scheduled work - when we can't proceed without erasing a block */
 128 static void mtdoops_workfunc_erase(struct work_struct *work)
 129 {
 130         struct mtdoops_context *cxt =
 131                         container_of(work, struct mtdoops_context, work_erase);
 132         struct mtd_info *mtd = cxt->mtd;
 133         int i = 0, j, ret, mod;
 134
 135         /* We were unregistered */
 136         if (!mtd)
 137                 return;
 138
 139         mod = (cxt->nextpage * OOPS_PAGE_SIZE) % mtd->erasesize;
 140         if (mod != 0) {
 141                 cxt->nextpage = cxt->nextpage + ((mtd->erasesize - mod) / OOPS_PAGE_SIZE);
 142                 if (cxt->nextpage > cxt->oops_pages)
 143                         cxt->nextpage = 0;
 144         }
 145
 146         while (mtd->block_isbad) {
 147                 ret = mtd->block_isbad(mtd, cxt->nextpage * OOPS_PAGE_SIZE);
 148                 if (!ret)
 149                         break;
 150                 if (ret < 0) {
 151                         printk(KERN_ERR "mtdoops: block_isbad failed, aborting.\n");
 152                         return;
 153                 }
 154 badblock:
 155                 printk(KERN_WARNING "mtdoops: Bad block at %08x\n",
 156                                 cxt->nextpage * OOPS_PAGE_SIZE);
 157                 i++;
 158                 cxt->nextpage = cxt->nextpage + (mtd->erasesize / OOPS_PAGE_SIZE);
 159                 if (cxt->nextpage > cxt->oops_pages)
 160                         cxt->nextpage = 0;
 161                 if (i == (cxt->oops_pages / (mtd->erasesize / OOPS_PAGE_SIZE))) {
 162                         printk(KERN_ERR "mtdoops: All blocks bad!\n");
 163                         return;
 164                 }
 165         }
 166
 167         for (j = 0, ret = -1; (j < 3) && (ret < 0); j++)
 168                 ret = mtdoops_erase_block(mtd, cxt->nextpage * OOPS_PAGE_SIZE);
 169
 170         if (ret >= 0) {
 171                 printk(KERN_DEBUG "mtdoops: Ready %d, %d \n", cxt->nextpage, cxt->nextcount);
 172                 cxt->ready = 1;
 173                 return;
 174         }
 175
 176         if (mtd->block_markbad && (ret == -EIO)) {
 177                 ret = mtd->block_markbad(mtd, cxt->nextpage * OOPS_PAGE_SIZE);
 178                 if (ret < 0) {
 179                         printk(KERN_ERR "mtdoops: block_markbad failed, aborting.\n");
 180                         return;
 181                 }
 182         }
 183         goto badblock;
 184 }
 185
 186 static void mtdoops_workfunc_write(struct work_struct *work)
 187 {
 188         struct mtdoops_context *cxt =
 189                         container_of(work, struct mtdoops_context, work_write);
 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         ret = mtd->write(mtd, cxt->nextpage * OOPS_PAGE_SIZE,
 199                                         OOPS_PAGE_SIZE, &retlen, cxt->oops_buf);
 200
 201         cxt->writecount = 0;
 202
 203         if ((retlen != OOPS_PAGE_SIZE) || (ret < 0))
 204                 printk(KERN_ERR "mtdoops: Write failure at %d (%td of %d written), err %d.\n",
 205                         cxt->nextpage * OOPS_PAGE_SIZE, retlen, OOPS_PAGE_SIZE, ret);
 206
 207         mtdoops_inc_counter(cxt);
 208 }
 209
 210 static void find_next_position(struct mtdoops_context *cxt)
 211 {
 212         struct mtd_info *mtd = cxt->mtd;
 213         int ret, page, maxpos = 0;
 214         u32 count, maxcount = 0xffffffff;
 215         size_t retlen;
 216
 217         for (page = 0; page < cxt->oops_pages; page++) {
 218                 ret = mtd->read(mtd, page * OOPS_PAGE_SIZE, 4, &retlen, (u_char *) &count);
 219                 if ((retlen != 4) || ((ret < 0) && (ret != -EUCLEAN))) {
 220                         printk(KERN_ERR "mtdoops: Read failure at %d (%td of 4 read)"
 221                                 ", err %d.\n", page * OOPS_PAGE_SIZE, retlen, ret);
 222                         continue;
 223                 }
 224
 225                 if (count == 0xffffffff)
 226                         continue;
 227                 if (maxcount == 0xffffffff) {
 228                         maxcount = count;
 229                         maxpos = page;
 230                 } else if ((count < 0x40000000) && (maxcount > 0xc0000000)) {
 231                         maxcount = count;
 232                         maxpos = page;
 233                 } else if ((count > maxcount) && (count < 0xc0000000)) {
 234                         maxcount = count;
 235                         maxpos = page;
 236                 } else if ((count > maxcount) && (count > 0xc0000000)
 237                                         && (maxcount > 0x80000000)) {
 238                         maxcount = count;
 239                         maxpos = page;
 240                 }
 241         }
 242         if (maxcount == 0xffffffff) {
 243                 cxt->nextpage = 0;
 244                 cxt->nextcount = 1;
 245                 cxt->ready = 1;
 246                 printk(KERN_DEBUG "mtdoops: Ready %d, %d (first init)\n",
 247                                 cxt->nextpage, cxt->nextcount);
 248                 return;
 249         }
 250
 251         cxt->nextpage = maxpos;
 252         cxt->nextcount = maxcount;
 253
 254         mtdoops_inc_counter(cxt);
 255 }
 256
 257
 258 static void mtdoops_notify_add(struct mtd_info *mtd)
 259 {
 260         struct mtdoops_context *cxt = &oops_cxt;
 261
 262         if ((mtd->index != cxt->mtd_index) || cxt->mtd_index < 0)
 263                 return;
 264
 265         if (mtd->size < (mtd->erasesize * 2)) {
 266                 printk(KERN_ERR "MTD partition %d not big enough for mtdoops\n",
 267                                 mtd->index);
 268                 return;
 269         }
 270
 271         if (mtd->erasesize < OOPS_PAGE_SIZE) {
 272                 printk(KERN_ERR "Eraseblock size of MTD partition %d too small\n",
 273                                 mtd->index);
 274                 return;
 275         }
 276
 277         cxt->mtd = mtd;
 278         cxt->oops_pages = mtd->size / OOPS_PAGE_SIZE;
 279
 280         find_next_position(cxt);
 281
 282         printk(KERN_INFO "mtdoops: Attached to MTD device %d\n", mtd->index);
 283 }
 284
 285 static void mtdoops_notify_remove(struct mtd_info *mtd)
 286 {
 287         struct mtdoops_context *cxt = &oops_cxt;
 288
 289         if ((mtd->index != cxt->mtd_index) || cxt->mtd_index < 0)
 290                 return;
 291
 292         cxt->mtd = NULL;
 293         flush_scheduled_work();
 294 }
 295
 296 static void mtdoops_console_sync(void)
 297 {
 298         struct mtdoops_context *cxt = &oops_cxt;
 299         struct mtd_info *mtd = cxt->mtd;
 300         unsigned long flags;
 301
 302         if (!cxt->ready || !mtd || cxt->writecount == 0)
 303                 return;
 304
 305         /*
 306          *  Once ready is 0 and we've held the lock no further writes to the
 307          *  buffer will happen
 308          */
 309         spin_lock_irqsave(&cxt->writecount_lock, flags);
 310         if (!cxt->ready) {
 311                 spin_unlock_irqrestore(&cxt->writecount_lock, flags);
 312                 return;
 313         }
 314         cxt->ready = 0;
 315         spin_unlock_irqrestore(&cxt->writecount_lock, flags);
 316
 317         schedule_work(&cxt->work_write);
 318 }
 319
 320 static void
 321 mtdoops_console_write(struct console *co, const char *s, unsigned int count)
 322 {
 323         struct mtdoops_context *cxt = co->data;
 324         struct mtd_info *mtd = cxt->mtd;
 325         unsigned long flags;
 326
 327         if (!oops_in_progress) {
 328                 mtdoops_console_sync();
 329                 return;
 330         }
 331
 332         if (!cxt->ready || !mtd)
 333                 return;
 334
 335         /* Locking on writecount ensures sequential writes to the buffer */
 336         spin_lock_irqsave(&cxt->writecount_lock, flags);
 337
 338         /* Check ready status didn't change whilst waiting for the lock */
 339         if (!cxt->ready)
 340                 return;
 341
 342         if (cxt->writecount == 0) {
 343                 u32 *stamp = cxt->oops_buf;
 344                 *stamp = cxt->nextcount;
 345                 cxt->writecount = 4;
 346         }
 347
 348         if ((count + cxt->writecount) > OOPS_PAGE_SIZE)
 349                 count = OOPS_PAGE_SIZE - cxt->writecount;
 350
 351         memcpy(cxt->oops_buf + cxt->writecount, s, count);
 352         cxt->writecount += count;
 353
 354         spin_unlock_irqrestore(&cxt->writecount_lock, flags);
 355
 356         if (cxt->writecount == OOPS_PAGE_SIZE)
 357                 mtdoops_console_sync();
 358 }
 359
 360 static int __init mtdoops_console_setup(struct console *co, char *options)
 361 {
 362         struct mtdoops_context *cxt = co->data;
 363
 364         if (cxt->mtd_index != -1)
 365                 return -EBUSY;
 366         if (co->index == -1)
 367                 return -EINVAL;
 368
 369         cxt->mtd_index = co->index;
 370         return 0;
 371 }
 372
 373 static struct mtd_notifier mtdoops_notifier = {
 374         .add    = mtdoops_notify_add,
 375         .remove = mtdoops_notify_remove,
 376 };
 377
 378 static struct console mtdoops_console = {
 379         .name           = "ttyMTD",
 380         .write          = mtdoops_console_write,
 381         .setup          = mtdoops_console_setup,
 382         .unblank        = mtdoops_console_sync,
 383         .index          = -1,
 384         .data           = &oops_cxt,
 385 };
 386
 387 static int __init mtdoops_console_init(void)
 388 {
 389         struct mtdoops_context *cxt = &oops_cxt;
 390
 391         cxt->mtd_index = -1;
 392         cxt->oops_buf = vmalloc(OOPS_PAGE_SIZE);
 393
 394         if (!cxt->oops_buf) {
 395                 printk(KERN_ERR "Failed to allocate mtdoops buffer workspace\n");
 396                 return -ENOMEM;
 397         }
 398
 399         INIT_WORK(&cxt->work_erase, mtdoops_workfunc_erase);
 400         INIT_WORK(&cxt->work_write, mtdoops_workfunc_write);
 401
 402         register_console(&mtdoops_console);
 403         register_mtd_user(&mtdoops_notifier);
 404         return 0;
 405 }
 406
 407 static void __exit mtdoops_console_exit(void)
 408 {
 409         struct mtdoops_context *cxt = &oops_cxt;
 410
 411         unregister_mtd_user(&mtdoops_notifier);
 412         unregister_console(&mtdoops_console);
 413         vfree(cxt->oops_buf);
 414 }
 415
 416
 417 subsys_initcall(mtdoops_console_init);
 418 module_exit(mtdoops_console_exit);
 419
 420 MODULE_LICENSE("GPL");
 421 MODULE_AUTHOR("Richard Purdie <rpurdie@openedhand.com>");
 422 MODULE_DESCRIPTION("MTD Oops/Panic console logger/driver");