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 OOPS_PAGE_SIZE 4096 37 38 struct mtdoops_context { 39 int mtd_index; 40 struct work_struct work_erase; 41 struct work_struct work_write; 42 struct mtd_info *mtd; 43 int oops_pages; 44 int nextpage; 45 int nextcount; 46 47 void *oops_buf; 48 49 /* writecount and disabling ready are spin lock protected */ 50 spinlock_t writecount_lock; 51 int ready; 52 int writecount; 53 } oops_cxt; 54 55 static void mtdoops_erase_callback(struct erase_info *done) 56 { 57 wait_queue_head_t *wait_q = (wait_queue_head_t *)done->priv; 58 wake_up(wait_q); 59 } 60 61 static int mtdoops_erase_block(struct mtd_info *mtd, int offset) 62 { 63 struct erase_info erase; 64 DECLARE_WAITQUEUE(wait, current); 65 wait_queue_head_t wait_q; 66 int ret; 67 68 init_waitqueue_head(&wait_q); 69 erase.mtd = mtd; 70 erase.callback = mtdoops_erase_callback; 71 erase.addr = offset; 72 erase.len = mtd->erasesize; 73 erase.priv = (u_long)&wait_q; 74 75 set_current_state(TASK_INTERRUPTIBLE); 76 add_wait_queue(&wait_q, &wait); 77 78 ret = mtd->erase(mtd, &erase); 79 if (ret) { 80 set_current_state(TASK_RUNNING); 81 remove_wait_queue(&wait_q, &wait); 82 printk (KERN_WARNING "mtdoops: erase of region [0x%x, 0x%x] " 83 "on \"%s\" failed\n", 84 erase.addr, erase.len, mtd->name); 85 return ret; 86 } 87 88 schedule(); /* Wait for erase to finish. */ 89 remove_wait_queue(&wait_q, &wait); 90 91 return 0; 92 } 93 94 static void mtdoops_inc_counter(struct mtdoops_context *cxt) 95 { 96 struct mtd_info *mtd = cxt->mtd; 97 size_t retlen; 98 u32 count; 99 int ret; 100 101 cxt->nextpage++; 102 if (cxt->nextpage > cxt->oops_pages) 103 cxt->nextpage = 0; 104 cxt->nextcount++; 105 if (cxt->nextcount == 0xffffffff) 106 cxt->nextcount = 0; 107 108 ret = mtd->read(mtd, cxt->nextpage * OOPS_PAGE_SIZE, 4, 109 &retlen, (u_char *) &count); 110 if ((retlen != 4) || ((ret < 0) && (ret != -EUCLEAN))) { 111 printk(KERN_ERR "mtdoops: Read failure at %d (%td of 4 read)" 112 ", err %d.\n", cxt->nextpage * OOPS_PAGE_SIZE, 113 retlen, ret); 114 schedule_work(&cxt->work_erase); 115 return; 116 } 117 118 /* See if we need to erase the next block */ 119 if (count != 0xffffffff) { 120 schedule_work(&cxt->work_erase); 121 return; 122 } 123 124 printk(KERN_DEBUG "mtdoops: Ready %d, %d (no erase)\n", 125 cxt->nextpage, cxt->nextcount); 126 cxt->ready = 1; 127 } 128 129 /* Scheduled work - when we can't proceed without erasing a block */ 130 static void mtdoops_workfunc_erase(struct work_struct *work) 131 { 132 struct mtdoops_context *cxt = 133 container_of(work, struct mtdoops_context, work_erase); 134 struct mtd_info *mtd = cxt->mtd; 135 int i = 0, j, ret, mod; 136 137 /* We were unregistered */ 138 if (!mtd) 139 return; 140 141 mod = (cxt->nextpage * OOPS_PAGE_SIZE) % mtd->erasesize; 142 if (mod != 0) { 143 cxt->nextpage = cxt->nextpage + ((mtd->erasesize - mod) / OOPS_PAGE_SIZE); 144 if (cxt->nextpage > cxt->oops_pages) 145 cxt->nextpage = 0; 146 } 147 148 while (mtd->block_isbad) { 149 ret = mtd->block_isbad(mtd, cxt->nextpage * OOPS_PAGE_SIZE); 150 if (!ret) 151 break; 152 if (ret < 0) { 153 printk(KERN_ERR "mtdoops: block_isbad failed, aborting.\n"); 154 return; 155 } 156 badblock: 157 printk(KERN_WARNING "mtdoops: Bad block at %08x\n", 158 cxt->nextpage * OOPS_PAGE_SIZE); 159 i++; 160 cxt->nextpage = cxt->nextpage + (mtd->erasesize / OOPS_PAGE_SIZE); 161 if (cxt->nextpage > cxt->oops_pages) 162 cxt->nextpage = 0; 163 if (i == (cxt->oops_pages / (mtd->erasesize / OOPS_PAGE_SIZE))) { 164 printk(KERN_ERR "mtdoops: All blocks bad!\n"); 165 return; 166 } 167 } 168 169 for (j = 0, ret = -1; (j < 3) && (ret < 0); j++) 170 ret = mtdoops_erase_block(mtd, cxt->nextpage * OOPS_PAGE_SIZE); 171 172 if (ret >= 0) { 173 printk(KERN_DEBUG "mtdoops: Ready %d, %d \n", cxt->nextpage, cxt->nextcount); 174 cxt->ready = 1; 175 return; 176 } 177 178 if (mtd->block_markbad && (ret == -EIO)) { 179 ret = mtd->block_markbad(mtd, cxt->nextpage * OOPS_PAGE_SIZE); 180 if (ret < 0) { 181 printk(KERN_ERR "mtdoops: block_markbad failed, aborting.\n"); 182 return; 183 } 184 } 185 goto badblock; 186 } 187 188 static void mtdoops_write(struct mtdoops_context *cxt, int panic) 189 { 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 if (panic) 199 ret = mtd->panic_write(mtd, cxt->nextpage * OOPS_PAGE_SIZE, 200 OOPS_PAGE_SIZE, &retlen, cxt->oops_buf); 201 else 202 ret = mtd->write(mtd, cxt->nextpage * OOPS_PAGE_SIZE, 203 OOPS_PAGE_SIZE, &retlen, cxt->oops_buf); 204 205 cxt->writecount = 0; 206 207 if ((retlen != OOPS_PAGE_SIZE) || (ret < 0)) 208 printk(KERN_ERR "mtdoops: Write failure at %d (%td of %d written), err %d.\n", 209 cxt->nextpage * OOPS_PAGE_SIZE, retlen, OOPS_PAGE_SIZE, ret); 210 211 mtdoops_inc_counter(cxt); 212 } 213 214 215 static void mtdoops_workfunc_write(struct work_struct *work) 216 { 217 struct mtdoops_context *cxt = 218 container_of(work, struct mtdoops_context, work_write); 219 220 mtdoops_write(cxt, 0); 221 } 222 223 static void find_next_position(struct mtdoops_context *cxt) 224 { 225 struct mtd_info *mtd = cxt->mtd; 226 int ret, page, maxpos = 0; 227 u32 count, maxcount = 0xffffffff; 228 size_t retlen; 229 230 for (page = 0; page < cxt->oops_pages; page++) { 231 ret = mtd->read(mtd, page * OOPS_PAGE_SIZE, 4, &retlen, (u_char *) &count); 232 if ((retlen != 4) || ((ret < 0) && (ret != -EUCLEAN))) { 233 printk(KERN_ERR "mtdoops: Read failure at %d (%td of 4 read)" 234 ", err %d.\n", page * OOPS_PAGE_SIZE, retlen, ret); 235 continue; 236 } 237 238 if (count == 0xffffffff) 239 continue; 240 if (maxcount == 0xffffffff) { 241 maxcount = count; 242 maxpos = page; 243 } else if ((count < 0x40000000) && (maxcount > 0xc0000000)) { 244 maxcount = count; 245 maxpos = page; 246 } else if ((count > maxcount) && (count < 0xc0000000)) { 247 maxcount = count; 248 maxpos = page; 249 } else if ((count > maxcount) && (count > 0xc0000000) 250 && (maxcount > 0x80000000)) { 251 maxcount = count; 252 maxpos = page; 253 } 254 } 255 if (maxcount == 0xffffffff) { 256 cxt->nextpage = 0; 257 cxt->nextcount = 1; 258 cxt->ready = 1; 259 printk(KERN_DEBUG "mtdoops: Ready %d, %d (first init)\n", 260 cxt->nextpage, cxt->nextcount); 261 return; 262 } 263 264 cxt->nextpage = maxpos; 265 cxt->nextcount = maxcount; 266 267 mtdoops_inc_counter(cxt); 268 } 269 270 271 static void mtdoops_notify_add(struct mtd_info *mtd) 272 { 273 struct mtdoops_context *cxt = &oops_cxt; 274 275 if ((mtd->index != cxt->mtd_index) || cxt->mtd_index < 0) 276 return; 277 278 if (mtd->size < (mtd->erasesize * 2)) { 279 printk(KERN_ERR "MTD partition %d not big enough for mtdoops\n", 280 mtd->index); 281 return; 282 } 283 284 if (mtd->erasesize < OOPS_PAGE_SIZE) { 285 printk(KERN_ERR "Eraseblock size of MTD partition %d too small\n", 286 mtd->index); 287 return; 288 } 289 290 cxt->mtd = mtd; 291 cxt->oops_pages = mtd->size / OOPS_PAGE_SIZE; 292 293 find_next_position(cxt); 294 295 printk(KERN_INFO "mtdoops: Attached to MTD device %d\n", mtd->index); 296 } 297 298 static void mtdoops_notify_remove(struct mtd_info *mtd) 299 { 300 struct mtdoops_context *cxt = &oops_cxt; 301 302 if ((mtd->index != cxt->mtd_index) || cxt->mtd_index < 0) 303 return; 304 305 cxt->mtd = NULL; 306 flush_scheduled_work(); 307 } 308 309 static void mtdoops_console_sync(void) 310 { 311 struct mtdoops_context *cxt = &oops_cxt; 312 struct mtd_info *mtd = cxt->mtd; 313 unsigned long flags; 314 315 if (!cxt->ready || !mtd || cxt->writecount == 0) 316 return; 317 318 /* 319 * Once ready is 0 and we've held the lock no further writes to the 320 * buffer will happen 321 */ 322 spin_lock_irqsave(&cxt->writecount_lock, flags); 323 if (!cxt->ready) { 324 spin_unlock_irqrestore(&cxt->writecount_lock, flags); 325 return; 326 } 327 cxt->ready = 0; 328 spin_unlock_irqrestore(&cxt->writecount_lock, flags); 329 330 if (mtd->panic_write && in_interrupt()) 331 /* Interrupt context, we're going to panic so try and log */ 332 mtdoops_write(cxt, 1); 333 else 334 schedule_work(&cxt->work_write); 335 } 336 337 static void 338 mtdoops_console_write(struct console *co, const char *s, unsigned int count) 339 { 340 struct mtdoops_context *cxt = co->data; 341 struct mtd_info *mtd = cxt->mtd; 342 unsigned long flags; 343 344 if (!oops_in_progress) { 345 mtdoops_console_sync(); 346 return; 347 } 348 349 if (!cxt->ready || !mtd) 350 return; 351 352 /* Locking on writecount ensures sequential writes to the buffer */ 353 spin_lock_irqsave(&cxt->writecount_lock, flags); 354 355 /* Check ready status didn't change whilst waiting for the lock */ 356 if (!cxt->ready) 357 return; 358 359 if (cxt->writecount == 0) { 360 u32 *stamp = cxt->oops_buf; 361 *stamp = cxt->nextcount; 362 cxt->writecount = 4; 363 } 364 365 if ((count + cxt->writecount) > OOPS_PAGE_SIZE) 366 count = OOPS_PAGE_SIZE - cxt->writecount; 367 368 memcpy(cxt->oops_buf + cxt->writecount, s, count); 369 cxt->writecount += count; 370 371 spin_unlock_irqrestore(&cxt->writecount_lock, flags); 372 373 if (cxt->writecount == OOPS_PAGE_SIZE) 374 mtdoops_console_sync(); 375 } 376 377 static int __init mtdoops_console_setup(struct console *co, char *options) 378 { 379 struct mtdoops_context *cxt = co->data; 380 381 if (cxt->mtd_index != -1) 382 return -EBUSY; 383 if (co->index == -1) 384 return -EINVAL; 385 386 cxt->mtd_index = co->index; 387 return 0; 388 } 389 390 static struct mtd_notifier mtdoops_notifier = { 391 .add = mtdoops_notify_add, 392 .remove = mtdoops_notify_remove, 393 }; 394 395 static struct console mtdoops_console = { 396 .name = "ttyMTD", 397 .write = mtdoops_console_write, 398 .setup = mtdoops_console_setup, 399 .unblank = mtdoops_console_sync, 400 .index = -1, 401 .data = &oops_cxt, 402 }; 403 404 static int __init mtdoops_console_init(void) 405 { 406 struct mtdoops_context *cxt = &oops_cxt; 407 408 cxt->mtd_index = -1; 409 cxt->oops_buf = vmalloc(OOPS_PAGE_SIZE); 410 411 if (!cxt->oops_buf) { 412 printk(KERN_ERR "Failed to allocate mtdoops buffer workspace\n"); 413 return -ENOMEM; 414 } 415 416 INIT_WORK(&cxt->work_erase, mtdoops_workfunc_erase); 417 INIT_WORK(&cxt->work_write, mtdoops_workfunc_write); 418 419 register_console(&mtdoops_console); 420 register_mtd_user(&mtdoops_notifier); 421 return 0; 422 } 423 424 static void __exit mtdoops_console_exit(void) 425 { 426 struct mtdoops_context *cxt = &oops_cxt; 427 428 unregister_mtd_user(&mtdoops_notifier); 429 unregister_console(&mtdoops_console); 430 vfree(cxt->oops_buf); 431 } 432 433 434 subsys_initcall(mtdoops_console_init); 435 module_exit(mtdoops_console_exit); 436 437 MODULE_LICENSE("GPL"); 438 MODULE_AUTHOR("Richard Purdie <rpurdie@openedhand.com>"); 439 MODULE_DESCRIPTION("MTD Oops/Panic console logger/driver"); 440