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%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_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 cxt->oops_pages = mtd->size / OOPS_PAGE_SIZE; 293 294 find_next_position(cxt); 295 296 printk(KERN_INFO "mtdoops: Attached to MTD device %d\n", mtd->index); 297 } 298 299 static void mtdoops_notify_remove(struct mtd_info *mtd) 300 { 301 struct mtdoops_context *cxt = &oops_cxt; 302 303 if ((mtd->index != cxt->mtd_index) || cxt->mtd_index < 0) 304 return; 305 306 cxt->mtd = NULL; 307 flush_scheduled_work(); 308 } 309 310 static void mtdoops_console_sync(void) 311 { 312 struct mtdoops_context *cxt = &oops_cxt; 313 struct mtd_info *mtd = cxt->mtd; 314 unsigned long flags; 315 316 if (!cxt->ready || !mtd || cxt->writecount == 0) 317 return; 318 319 /* 320 * Once ready is 0 and we've held the lock no further writes to the 321 * buffer will happen 322 */ 323 spin_lock_irqsave(&cxt->writecount_lock, flags); 324 if (!cxt->ready) { 325 spin_unlock_irqrestore(&cxt->writecount_lock, flags); 326 return; 327 } 328 cxt->ready = 0; 329 spin_unlock_irqrestore(&cxt->writecount_lock, flags); 330 331 if (mtd->panic_write && in_interrupt()) 332 /* Interrupt context, we're going to panic so try and log */ 333 mtdoops_write(cxt, 1); 334 else 335 schedule_work(&cxt->work_write); 336 } 337 338 static void 339 mtdoops_console_write(struct console *co, const char *s, unsigned int count) 340 { 341 struct mtdoops_context *cxt = co->data; 342 struct mtd_info *mtd = cxt->mtd; 343 unsigned long flags; 344 345 if (!oops_in_progress) { 346 mtdoops_console_sync(); 347 return; 348 } 349 350 if (!cxt->ready || !mtd) 351 return; 352 353 /* Locking on writecount ensures sequential writes to the buffer */ 354 spin_lock_irqsave(&cxt->writecount_lock, flags); 355 356 /* Check ready status didn't change whilst waiting for the lock */ 357 if (!cxt->ready) 358 return; 359 360 if (cxt->writecount == 0) { 361 u32 *stamp = cxt->oops_buf; 362 *stamp++ = cxt->nextcount; 363 *stamp = MTDOOPS_KERNMSG_MAGIC; 364 cxt->writecount = 8; 365 } 366 367 if ((count + cxt->writecount) > OOPS_PAGE_SIZE) 368 count = OOPS_PAGE_SIZE - cxt->writecount; 369 370 memcpy(cxt->oops_buf + cxt->writecount, s, count); 371 cxt->writecount += count; 372 373 spin_unlock_irqrestore(&cxt->writecount_lock, flags); 374 375 if (cxt->writecount == OOPS_PAGE_SIZE) 376 mtdoops_console_sync(); 377 } 378 379 static int __init mtdoops_console_setup(struct console *co, char *options) 380 { 381 struct mtdoops_context *cxt = co->data; 382 383 if (cxt->mtd_index != -1) 384 return -EBUSY; 385 if (co->index == -1) 386 return -EINVAL; 387 388 cxt->mtd_index = co->index; 389 return 0; 390 } 391 392 static struct mtd_notifier mtdoops_notifier = { 393 .add = mtdoops_notify_add, 394 .remove = mtdoops_notify_remove, 395 }; 396 397 static struct console mtdoops_console = { 398 .name = "ttyMTD", 399 .write = mtdoops_console_write, 400 .setup = mtdoops_console_setup, 401 .unblank = mtdoops_console_sync, 402 .index = -1, 403 .data = &oops_cxt, 404 }; 405 406 static int __init mtdoops_console_init(void) 407 { 408 struct mtdoops_context *cxt = &oops_cxt; 409 410 cxt->mtd_index = -1; 411 cxt->oops_buf = vmalloc(OOPS_PAGE_SIZE); 412 413 if (!cxt->oops_buf) { 414 printk(KERN_ERR "Failed to allocate mtdoops buffer workspace\n"); 415 return -ENOMEM; 416 } 417 418 INIT_WORK(&cxt->work_erase, mtdoops_workfunc_erase); 419 INIT_WORK(&cxt->work_write, mtdoops_workfunc_write); 420 421 register_console(&mtdoops_console); 422 register_mtd_user(&mtdoops_notifier); 423 return 0; 424 } 425 426 static void __exit mtdoops_console_exit(void) 427 { 428 struct mtdoops_context *cxt = &oops_cxt; 429 430 unregister_mtd_user(&mtdoops_notifier); 431 unregister_console(&mtdoops_console); 432 vfree(cxt->oops_buf); 433 } 434 435 436 subsys_initcall(mtdoops_console_init); 437 module_exit(mtdoops_console_exit); 438 439 MODULE_LICENSE("GPL"); 440 MODULE_AUTHOR("Richard Purdie <rpurdie@openedhand.com>"); 441 MODULE_DESCRIPTION("MTD Oops/Panic console logger/driver"); 442