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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         if (mtd->erasesize < OOPS_PAGE_SIZE)
  71                 erase.len = OOPS_PAGE_SIZE;
  72         else
  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%x, 0x%x] "
  84                                      "on \"%s\" failed\n",
  85                         erase.addr, 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_workfunc_write(struct work_struct *work)
 190 {
 191         struct mtdoops_context *cxt =
 192                         container_of(work, struct mtdoops_context, work_write);
 193         struct mtd_info *mtd = cxt->mtd;
 194         size_t retlen;
 195         int ret;
 196
 197         if (cxt->writecount < OOPS_PAGE_SIZE)
 198                 memset(cxt->oops_buf + cxt->writecount, 0xff,
 199                                         OOPS_PAGE_SIZE - cxt->writecount);
 200
 201         ret = mtd->write(mtd, cxt->nextpage * OOPS_PAGE_SIZE,
 202                                         OOPS_PAGE_SIZE, &retlen, cxt->oops_buf);
 203
 204         cxt->writecount = 0;
 205
 206         if ((retlen != OOPS_PAGE_SIZE) || (ret < 0))
 207                 printk(KERN_ERR "mtdoops: Write failure at %d (%td of %d written), err %d.\n",
 208                         cxt->nextpage * OOPS_PAGE_SIZE, retlen, OOPS_PAGE_SIZE, ret);
 209
 210         mtdoops_inc_counter(cxt);
 211 }
 212
 213 static void find_next_position(struct mtdoops_context *cxt)
 214 {
 215         struct mtd_info *mtd = cxt->mtd;
 216         int ret, page, maxpos = 0;
 217         u32 count, maxcount = 0xffffffff;
 218         size_t retlen;
 219
 220         for (page = 0; page < cxt->oops_pages; page++) {
 221                 ret = mtd->read(mtd, page * OOPS_PAGE_SIZE, 4, &retlen, (u_char *) &count);
 222                 if ((retlen != 4) || ((ret < 0) && (ret != -EUCLEAN))) {
 223                         printk(KERN_ERR "mtdoops: Read failure at %d (%td of 4 read)"
 224                                 ", err %d.\n", page * OOPS_PAGE_SIZE, retlen, ret);
 225                         continue;
 226                 }
 227
 228                 if (count == 0xffffffff)
 229                         continue;
 230                 if (maxcount == 0xffffffff) {
 231                         maxcount = count;
 232                         maxpos = page;
 233                 } else if ((count < 0x40000000) && (maxcount > 0xc0000000)) {
 234                         maxcount = count;
 235                         maxpos = page;
 236                 } else if ((count > maxcount) && (count < 0xc0000000)) {
 237                         maxcount = count;
 238                         maxpos = page;
 239                 } else if ((count > maxcount) && (count > 0xc0000000)
 240                                         && (maxcount > 0x80000000)) {
 241                         maxcount = count;
 242                         maxpos = page;
 243                 }
 244         }
 245         if (maxcount == 0xffffffff) {
 246                 cxt->nextpage = 0;
 247                 cxt->nextcount = 1;
 248                 cxt->ready = 1;
 249                 printk(KERN_DEBUG "mtdoops: Ready %d, %d (first init)\n",
 250                                 cxt->nextpage, cxt->nextcount);
 251                 return;
 252         }
 253
 254         cxt->nextpage = maxpos;
 255         cxt->nextcount = maxcount;
 256
 257         mtdoops_inc_counter(cxt);
 258 }
 259
 260
 261 static void mtdoops_notify_add(struct mtd_info *mtd)
 262 {
 263         struct mtdoops_context *cxt = &oops_cxt;
 264
 265         if ((mtd->index != cxt->mtd_index) || cxt->mtd_index < 0)
 266                 return;
 267
 268         if (mtd->size < (mtd->erasesize * 2)) {
 269                 printk(KERN_ERR "MTD partition %d not big enough for mtdoops\n",
 270                                 mtd->index);
 271                 return;
 272         }
 273
 274         cxt->mtd = mtd;
 275         cxt->oops_pages = mtd->size / OOPS_PAGE_SIZE;
 276
 277         find_next_position(cxt);
 278
 279         printk(KERN_DEBUG "mtdoops: Attached to MTD device %d\n", mtd->index);
 280 }
 281
 282 static void mtdoops_notify_remove(struct mtd_info *mtd)
 283 {
 284         struct mtdoops_context *cxt = &oops_cxt;
 285
 286         if ((mtd->index != cxt->mtd_index) || cxt->mtd_index < 0)
 287                 return;
 288
 289         cxt->mtd = NULL;
 290         flush_scheduled_work();
 291 }
 292
 293 static void mtdoops_console_sync(void)
 294 {
 295         struct mtdoops_context *cxt = &oops_cxt;
 296         struct mtd_info *mtd = cxt->mtd;
 297         unsigned long flags;
 298
 299         if (!cxt->ready || !mtd || cxt->writecount == 0)
 300                 return;
 301
 302         /*
 303          *  Once ready is 0 and we've held the lock no further writes to the
 304          *  buffer will happen
 305          */
 306         spin_lock_irqsave(&cxt->writecount_lock, flags);
 307         if (!cxt->ready) {
 308                 spin_unlock_irqrestore(&cxt->writecount_lock, flags);
 309                 return;
 310         }
 311         cxt->ready = 0;
 312         spin_unlock_irqrestore(&cxt->writecount_lock, flags);
 313
 314         schedule_work(&cxt->work_write);
 315 }
 316
 317 static void
 318 mtdoops_console_write(struct console *co, const char *s, unsigned int count)
 319 {
 320         struct mtdoops_context *cxt = co->data;
 321         struct mtd_info *mtd = cxt->mtd;
 322         unsigned long flags;
 323
 324         if (!oops_in_progress) {
 325                 mtdoops_console_sync();
 326                 return;
 327         }
 328
 329         if (!cxt->ready || !mtd)
 330                 return;
 331
 332         /* Locking on writecount ensures sequential writes to the buffer */
 333         spin_lock_irqsave(&cxt->writecount_lock, flags);
 334
 335         /* Check ready status didn't change whilst waiting for the lock */
 336         if (!cxt->ready)
 337                 return;
 338
 339         if (cxt->writecount == 0) {
 340                 u32 *stamp = cxt->oops_buf;
 341                 *stamp = cxt->nextcount;
 342                 cxt->writecount = 4;
 343         }
 344
 345         if ((count + cxt->writecount) > OOPS_PAGE_SIZE)
 346                 count = OOPS_PAGE_SIZE - cxt->writecount;
 347
 348         memcpy(cxt->oops_buf + cxt->writecount, s, count);
 349         cxt->writecount += count;
 350
 351         spin_unlock_irqrestore(&cxt->writecount_lock, flags);
 352
 353         if (cxt->writecount == OOPS_PAGE_SIZE)
 354                 mtdoops_console_sync();
 355 }
 356
 357 static int __init mtdoops_console_setup(struct console *co, char *options)
 358 {
 359         struct mtdoops_context *cxt = co->data;
 360
 361         if (cxt->mtd_index != -1)
 362                 return -EBUSY;
 363         if (co->index == -1)
 364                 return -EINVAL;
 365
 366         cxt->mtd_index = co->index;
 367         return 0;
 368 }
 369
 370 static struct mtd_notifier mtdoops_notifier = {
 371         .add    = mtdoops_notify_add,
 372         .remove = mtdoops_notify_remove,
 373 };
 374
 375 static struct console mtdoops_console = {
 376         .name           = "ttyMTD",
 377         .write          = mtdoops_console_write,
 378         .setup          = mtdoops_console_setup,
 379         .unblank        = mtdoops_console_sync,
 380         .flags          = CON_PRINTBUFFER,
 381         .index          = -1,
 382         .data           = &oops_cxt,
 383 };
 384
 385 static int __init mtdoops_console_init(void)
 386 {
 387         struct mtdoops_context *cxt = &oops_cxt;
 388
 389         cxt->mtd_index = -1;
 390         cxt->oops_buf = vmalloc(OOPS_PAGE_SIZE);
 391
 392         if (!cxt->oops_buf) {
 393                 printk(KERN_ERR "Failed to allocate oops buffer workspace\n");
 394                 return -ENOMEM;
 395         }
 396
 397         INIT_WORK(&cxt->work_erase, mtdoops_workfunc_erase);
 398         INIT_WORK(&cxt->work_write, mtdoops_workfunc_write);
 399
 400         register_console(&mtdoops_console);
 401         register_mtd_user(&mtdoops_notifier);
 402         return 0;
 403 }
 404
 405 static void __exit mtdoops_console_exit(void)
 406 {
 407         struct mtdoops_context *cxt = &oops_cxt;
 408
 409         unregister_mtd_user(&mtdoops_notifier);
 410         unregister_console(&mtdoops_console);
 411         vfree(cxt->oops_buf);
 412 }
 413
 414
 415 subsys_initcall(mtdoops_console_init);
 416 module_exit(mtdoops_console_exit);
 417
 418 MODULE_LICENSE("GPL");
 419 MODULE_AUTHOR("Richard Purdie <rpurdie@openedhand.com>");
 420 MODULE_DESCRIPTION("MTD Oops/Panic console logger/driver");