mtdblock.c revision 191876729901d0c8dab8a331f9a1e4b73a56457b
197894cda5773e59bd13e87b72077751099419a9fThomas Gleixner/* 21da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * Direct MTD block device access 31da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * 497894cda5773e59bd13e87b72077751099419a9fThomas Gleixner * $Id: mtdblock.c,v 1.68 2005/11/07 11:14:20 gleixner Exp $ 51da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * 61da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * (C) 2000-2003 Nicolas Pitre <nico@cam.org> 71da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * (C) 1999-2003 David Woodhouse <dwmw2@infradead.org> 81da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds */ 91da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 101da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds#include <linux/fs.h> 111da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds#include <linux/init.h> 1215fdc52f35b853e3fa550087987b5ee4ffbd199bThomas Gleixner#include <linux/kernel.h> 1315fdc52f35b853e3fa550087987b5ee4ffbd199bThomas Gleixner#include <linux/module.h> 1415fdc52f35b853e3fa550087987b5ee4ffbd199bThomas Gleixner#include <linux/sched.h> 151da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds#include <linux/slab.h> 1615fdc52f35b853e3fa550087987b5ee4ffbd199bThomas Gleixner#include <linux/types.h> 171da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds#include <linux/vmalloc.h> 1815fdc52f35b853e3fa550087987b5ee4ffbd199bThomas Gleixner 191da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds#include <linux/mtd/mtd.h> 201da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds#include <linux/mtd/blktrans.h> 2148b192686dd20cb1576ae1d8ccd17a07971ef24aIngo Molnar#include <linux/mutex.h> 2248b192686dd20cb1576ae1d8ccd17a07971ef24aIngo Molnar 231da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 241da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvaldsstatic struct mtdblk_dev { 251da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds struct mtd_info *mtd; 261da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds int count; 2748b192686dd20cb1576ae1d8ccd17a07971ef24aIngo Molnar struct mutex cache_mutex; 281da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds unsigned char *cache_data; 291da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds unsigned long cache_offset; 301da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds unsigned int cache_size; 311da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds enum { STATE_EMPTY, STATE_CLEAN, STATE_DIRTY } cache_state; 321da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds} *mtdblks[MAX_MTD_DEVICES]; 331da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 341da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds/* 351da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * Cache stuff... 3697894cda5773e59bd13e87b72077751099419a9fThomas Gleixner * 371da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * Since typical flash erasable sectors are much larger than what Linux's 381da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * buffer cache can handle, we must implement read-modify-write on flash 391da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * sectors for each block write requests. To avoid over-erasing flash sectors 401da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * and to speed things up, we locally cache a whole flash sector while it is 411da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * being written to until a different sector is required. 421da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds */ 431da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 441da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvaldsstatic void erase_callback(struct erase_info *done) 451da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds{ 461da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds wait_queue_head_t *wait_q = (wait_queue_head_t *)done->priv; 471da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds wake_up(wait_q); 481da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds} 491da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 5097894cda5773e59bd13e87b72077751099419a9fThomas Gleixnerstatic int erase_write (struct mtd_info *mtd, unsigned long pos, 511da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds int len, const char *buf) 521da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds{ 531da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds struct erase_info erase; 541da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds DECLARE_WAITQUEUE(wait, current); 551da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds wait_queue_head_t wait_q; 561da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds size_t retlen; 571da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds int ret; 581da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 591da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds /* 601da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * First, let's erase the flash block. 611da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds */ 621da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 631da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds init_waitqueue_head(&wait_q); 641da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds erase.mtd = mtd; 651da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds erase.callback = erase_callback; 661da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds erase.addr = pos; 671da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds erase.len = len; 681da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds erase.priv = (u_long)&wait_q; 691da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 701da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds set_current_state(TASK_INTERRUPTIBLE); 711da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds add_wait_queue(&wait_q, &wait); 721da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 73f4a43cfcecfcaeeaa40a9dbc1d1378298c22446eThomas Gleixner ret = mtd->erase(mtd, &erase); 741da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (ret) { 751da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds set_current_state(TASK_RUNNING); 761da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds remove_wait_queue(&wait_q, &wait); 771da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds printk (KERN_WARNING "mtdblock: erase of region [0x%lx, 0x%x] " 781da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds "on \"%s\" failed\n", 791da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds pos, len, mtd->name); 801da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds return ret; 811da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } 821da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 831da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds schedule(); /* Wait for erase to finish. */ 841da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds remove_wait_queue(&wait_q, &wait); 851da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 861da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds /* 871da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * Next, writhe data to flash. 881da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds */ 891da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 90f4a43cfcecfcaeeaa40a9dbc1d1378298c22446eThomas Gleixner ret = mtd->write(mtd, pos, len, &retlen, buf); 911da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (ret) 921da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds return ret; 931da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (retlen != len) 941da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds return -EIO; 951da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds return 0; 961da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds} 971da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 981da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 991da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvaldsstatic int write_cached_data (struct mtdblk_dev *mtdblk) 1001da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds{ 1011da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds struct mtd_info *mtd = mtdblk->mtd; 1021da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds int ret; 1031da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 1041da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (mtdblk->cache_state != STATE_DIRTY) 1051da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds return 0; 1061da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 1071da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds DEBUG(MTD_DEBUG_LEVEL2, "mtdblock: writing cached data for \"%s\" " 10897894cda5773e59bd13e87b72077751099419a9fThomas Gleixner "at 0x%lx, size 0x%x\n", mtd->name, 1091da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds mtdblk->cache_offset, mtdblk->cache_size); 11097894cda5773e59bd13e87b72077751099419a9fThomas Gleixner 11197894cda5773e59bd13e87b72077751099419a9fThomas Gleixner ret = erase_write (mtd, mtdblk->cache_offset, 1121da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds mtdblk->cache_size, mtdblk->cache_data); 1131da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (ret) 1141da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds return ret; 1151da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 1161da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds /* 1171da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * Here we could argubly set the cache state to STATE_CLEAN. 11897894cda5773e59bd13e87b72077751099419a9fThomas Gleixner * However this could lead to inconsistency since we will not 11997894cda5773e59bd13e87b72077751099419a9fThomas Gleixner * be notified if this content is altered on the flash by other 1201da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * means. Let's declare it empty and leave buffering tasks to 1211da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * the buffer cache instead. 1221da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds */ 1231da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds mtdblk->cache_state = STATE_EMPTY; 1241da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds return 0; 1251da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds} 1261da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 1271da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 12897894cda5773e59bd13e87b72077751099419a9fThomas Gleixnerstatic int do_cached_write (struct mtdblk_dev *mtdblk, unsigned long pos, 1291da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds int len, const char *buf) 1301da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds{ 1311da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds struct mtd_info *mtd = mtdblk->mtd; 1321da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds unsigned int sect_size = mtdblk->cache_size; 1331da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds size_t retlen; 1341da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds int ret; 1351da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 1361da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds DEBUG(MTD_DEBUG_LEVEL2, "mtdblock: write on \"%s\" at 0x%lx, size 0x%x\n", 1371da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds mtd->name, pos, len); 13897894cda5773e59bd13e87b72077751099419a9fThomas Gleixner 1391da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (!sect_size) 140f4a43cfcecfcaeeaa40a9dbc1d1378298c22446eThomas Gleixner return mtd->write(mtd, pos, len, &retlen, buf); 1411da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 1421da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds while (len > 0) { 1431da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds unsigned long sect_start = (pos/sect_size)*sect_size; 1441da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds unsigned int offset = pos - sect_start; 1451da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds unsigned int size = sect_size - offset; 14697894cda5773e59bd13e87b72077751099419a9fThomas Gleixner if( size > len ) 1471da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds size = len; 1481da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 1491da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (size == sect_size) { 15097894cda5773e59bd13e87b72077751099419a9fThomas Gleixner /* 1511da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * We are covering a whole sector. Thus there is no 1521da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * need to bother with the cache while it may still be 1531da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * useful for other partial writes. 1541da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds */ 1551da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds ret = erase_write (mtd, pos, size, buf); 1561da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (ret) 1571da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds return ret; 1581da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } else { 1591da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds /* Partial sector: need to use the cache */ 1601da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 1611da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (mtdblk->cache_state == STATE_DIRTY && 1621da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds mtdblk->cache_offset != sect_start) { 1631da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds ret = write_cached_data(mtdblk); 16497894cda5773e59bd13e87b72077751099419a9fThomas Gleixner if (ret) 1651da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds return ret; 1661da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } 1671da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 1681da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (mtdblk->cache_state == STATE_EMPTY || 1691da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds mtdblk->cache_offset != sect_start) { 1701da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds /* fill the cache with the current sector */ 1711da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds mtdblk->cache_state = STATE_EMPTY; 172f4a43cfcecfcaeeaa40a9dbc1d1378298c22446eThomas Gleixner ret = mtd->read(mtd, sect_start, sect_size, 173f4a43cfcecfcaeeaa40a9dbc1d1378298c22446eThomas Gleixner &retlen, mtdblk->cache_data); 1741da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (ret) 1751da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds return ret; 1761da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (retlen != sect_size) 1771da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds return -EIO; 1781da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 1791da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds mtdblk->cache_offset = sect_start; 1801da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds mtdblk->cache_size = sect_size; 1811da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds mtdblk->cache_state = STATE_CLEAN; 1821da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } 1831da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 1841da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds /* write data to our local cache */ 1851da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds memcpy (mtdblk->cache_data + offset, buf, size); 1861da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds mtdblk->cache_state = STATE_DIRTY; 1871da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } 1881da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 1891da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds buf += size; 1901da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds pos += size; 1911da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds len -= size; 1921da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } 1931da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 1941da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds return 0; 1951da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds} 1961da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 1971da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 19897894cda5773e59bd13e87b72077751099419a9fThomas Gleixnerstatic int do_cached_read (struct mtdblk_dev *mtdblk, unsigned long pos, 1991da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds int len, char *buf) 2001da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds{ 2011da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds struct mtd_info *mtd = mtdblk->mtd; 2021da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds unsigned int sect_size = mtdblk->cache_size; 2031da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds size_t retlen; 2041da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds int ret; 2051da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 20697894cda5773e59bd13e87b72077751099419a9fThomas Gleixner DEBUG(MTD_DEBUG_LEVEL2, "mtdblock: read on \"%s\" at 0x%lx, size 0x%x\n", 2071da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds mtd->name, pos, len); 20897894cda5773e59bd13e87b72077751099419a9fThomas Gleixner 2091da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (!sect_size) 210f4a43cfcecfcaeeaa40a9dbc1d1378298c22446eThomas Gleixner return mtd->read(mtd, pos, len, &retlen, buf); 2111da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 2121da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds while (len > 0) { 2131da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds unsigned long sect_start = (pos/sect_size)*sect_size; 2141da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds unsigned int offset = pos - sect_start; 2151da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds unsigned int size = sect_size - offset; 21697894cda5773e59bd13e87b72077751099419a9fThomas Gleixner if (size > len) 2171da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds size = len; 2181da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 2191da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds /* 2201da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * Check if the requested data is already cached 2211da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * Read the requested amount of data from our internal cache if it 2221da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * contains what we want, otherwise we read the data directly 2231da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * from flash. 2241da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds */ 2251da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (mtdblk->cache_state != STATE_EMPTY && 2261da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds mtdblk->cache_offset == sect_start) { 2271da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds memcpy (buf, mtdblk->cache_data + offset, size); 2281da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } else { 229f4a43cfcecfcaeeaa40a9dbc1d1378298c22446eThomas Gleixner ret = mtd->read(mtd, pos, size, &retlen, buf); 2301da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (ret) 2311da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds return ret; 2321da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (retlen != size) 2331da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds return -EIO; 2341da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } 2351da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 2361da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds buf += size; 2371da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds pos += size; 2381da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds len -= size; 2391da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } 2401da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 2411da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds return 0; 2421da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds} 2431da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 2441da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvaldsstatic int mtdblock_readsect(struct mtd_blktrans_dev *dev, 2451da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds unsigned long block, char *buf) 2461da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds{ 2471da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds struct mtdblk_dev *mtdblk = mtdblks[dev->devnum]; 2481da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds return do_cached_read(mtdblk, block<<9, 512, buf); 2491da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds} 2501da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 2511da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvaldsstatic int mtdblock_writesect(struct mtd_blktrans_dev *dev, 2521da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds unsigned long block, char *buf) 2531da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds{ 2541da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds struct mtdblk_dev *mtdblk = mtdblks[dev->devnum]; 2551da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (unlikely(!mtdblk->cache_data && mtdblk->cache_size)) { 2561da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds mtdblk->cache_data = vmalloc(mtdblk->mtd->erasesize); 2571da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (!mtdblk->cache_data) 2581da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds return -EINTR; 2591da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds /* -EINTR is not really correct, but it is the best match 2601da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * documented in man 2 write for all cases. We could also 2611da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * return -EAGAIN sometimes, but why bother? 2621da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds */ 2631da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } 2641da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds return do_cached_write(mtdblk, block<<9, 512, buf); 2651da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds} 2661da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 2671da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvaldsstatic int mtdblock_open(struct mtd_blktrans_dev *mbd) 2681da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds{ 2691da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds struct mtdblk_dev *mtdblk; 2701da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds struct mtd_info *mtd = mbd->mtd; 2711da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds int dev = mbd->devnum; 2721da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 2731da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds DEBUG(MTD_DEBUG_LEVEL1,"mtdblock_open\n"); 27497894cda5773e59bd13e87b72077751099419a9fThomas Gleixner 2751da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (mtdblks[dev]) { 2761da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds mtdblks[dev]->count++; 2771da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds return 0; 2781da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } 27997894cda5773e59bd13e87b72077751099419a9fThomas Gleixner 2801da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds /* OK, it's not open. Create cache info for it */ 2811da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds mtdblk = kmalloc(sizeof(struct mtdblk_dev), GFP_KERNEL); 2821da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (!mtdblk) 2831da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds return -ENOMEM; 2841da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 2851da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds memset(mtdblk, 0, sizeof(*mtdblk)); 2861da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds mtdblk->count = 1; 2871da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds mtdblk->mtd = mtd; 2881da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 28948b192686dd20cb1576ae1d8ccd17a07971ef24aIngo Molnar mutex_init(&mtdblk->cache_mutex); 2901da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds mtdblk->cache_state = STATE_EMPTY; 29192cbfdcc3661d7670b01b92b89811cd3a2412297Joern Engel if ( !(mtdblk->mtd->flags & MTD_NO_ERASE) && mtdblk->mtd->erasesize) { 2921da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds mtdblk->cache_size = mtdblk->mtd->erasesize; 2931da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds mtdblk->cache_data = NULL; 2941da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } 2951da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 2961da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds mtdblks[dev] = mtdblk; 29797894cda5773e59bd13e87b72077751099419a9fThomas Gleixner 2981da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds DEBUG(MTD_DEBUG_LEVEL1, "ok\n"); 2991da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 3001da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds return 0; 3011da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds} 3021da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 3031da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvaldsstatic int mtdblock_release(struct mtd_blktrans_dev *mbd) 3041da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds{ 3051da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds int dev = mbd->devnum; 3061da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds struct mtdblk_dev *mtdblk = mtdblks[dev]; 3071da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 3081da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds DEBUG(MTD_DEBUG_LEVEL1, "mtdblock_release\n"); 3091da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 31048b192686dd20cb1576ae1d8ccd17a07971ef24aIngo Molnar mutex_lock(&mtdblk->cache_mutex); 3111da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds write_cached_data(mtdblk); 31248b192686dd20cb1576ae1d8ccd17a07971ef24aIngo Molnar mutex_unlock(&mtdblk->cache_mutex); 3131da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 3141da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (!--mtdblk->count) { 3151da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds /* It was the last usage. Free the device */ 3161da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds mtdblks[dev] = NULL; 3171da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (mtdblk->mtd->sync) 3181da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds mtdblk->mtd->sync(mtdblk->mtd); 3191da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds vfree(mtdblk->cache_data); 3201da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds kfree(mtdblk); 3211da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } 3221da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds DEBUG(MTD_DEBUG_LEVEL1, "ok\n"); 3231da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 3241da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds return 0; 32597894cda5773e59bd13e87b72077751099419a9fThomas Gleixner} 3261da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 3271da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvaldsstatic int mtdblock_flush(struct mtd_blktrans_dev *dev) 3281da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds{ 3291da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds struct mtdblk_dev *mtdblk = mtdblks[dev->devnum]; 3301da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 33148b192686dd20cb1576ae1d8ccd17a07971ef24aIngo Molnar mutex_lock(&mtdblk->cache_mutex); 3321da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds write_cached_data(mtdblk); 33348b192686dd20cb1576ae1d8ccd17a07971ef24aIngo Molnar mutex_unlock(&mtdblk->cache_mutex); 3341da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 3351da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (mtdblk->mtd->sync) 3361da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds mtdblk->mtd->sync(mtdblk->mtd); 3371da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds return 0; 3381da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds} 3391da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 3401da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvaldsstatic void mtdblock_add_mtd(struct mtd_blktrans_ops *tr, struct mtd_info *mtd) 3411da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds{ 3421da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds struct mtd_blktrans_dev *dev = kmalloc(sizeof(*dev), GFP_KERNEL); 3431da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 3441da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (!dev) 3451da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds return; 3461da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 3471da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds memset(dev, 0, sizeof(*dev)); 3481da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 3491da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds dev->mtd = mtd; 3501da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds dev->devnum = mtd->index; 351191876729901d0c8dab8a331f9a1e4b73a56457bRichard Purdie 3521da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds dev->size = mtd->size >> 9; 3531da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds dev->tr = tr; 3541da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 3551da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (!(mtd->flags & MTD_WRITEABLE)) 3561da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds dev->readonly = 1; 3571da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 3581da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds add_mtd_blktrans_dev(dev); 3591da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds} 3601da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 3611da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvaldsstatic void mtdblock_remove_dev(struct mtd_blktrans_dev *dev) 3621da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds{ 3631da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds del_mtd_blktrans_dev(dev); 3641da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds kfree(dev); 3651da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds} 3661da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 3671da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvaldsstatic struct mtd_blktrans_ops mtdblock_tr = { 3681da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds .name = "mtdblock", 3691da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds .major = 31, 3701da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds .part_bits = 0, 371191876729901d0c8dab8a331f9a1e4b73a56457bRichard Purdie .blksize = 512, 3721da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds .open = mtdblock_open, 3731da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds .flush = mtdblock_flush, 3741da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds .release = mtdblock_release, 3751da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds .readsect = mtdblock_readsect, 3761da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds .writesect = mtdblock_writesect, 3771da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds .add_mtd = mtdblock_add_mtd, 3781da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds .remove_dev = mtdblock_remove_dev, 3791da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds .owner = THIS_MODULE, 3801da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds}; 3811da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 3821da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvaldsstatic int __init init_mtdblock(void) 3831da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds{ 3841da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds return register_mtd_blktrans(&mtdblock_tr); 3851da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds} 3861da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 3871da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvaldsstatic void __exit cleanup_mtdblock(void) 3881da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds{ 3891da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds deregister_mtd_blktrans(&mtdblock_tr); 3901da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds} 3911da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 3921da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvaldsmodule_init(init_mtdblock); 3931da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvaldsmodule_exit(cleanup_mtdblock); 3941da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 3951da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 3961da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus TorvaldsMODULE_LICENSE("GPL"); 3971da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus TorvaldsMODULE_AUTHOR("Nicolas Pitre <nico@cam.org> et al."); 3981da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus TorvaldsMODULE_DESCRIPTION("Caching read/erase/writeback block device emulation access to MTD devices"); 399