/**************************************************************************** * fs/fat/fs_configfat.c * * Copyright (C) 2008-2009, 2013 Gregory Nutt. All rights reserved. * Author: Gregory Nutt * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in * the documentation and/or other materials provided with the * distribution. * 3. Neither the name NuttX nor the names of its contributors may be * used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. * ****************************************************************************/ /**************************************************************************** * Included Files ****************************************************************************/ #include #include #include #include #include #include #include #include #include "inode/inode.h" #include "fs_fat32.h" #include "fs_mkfatfs.h" /**************************************************************************** * Pre-processor Definitions ****************************************************************************/ #define NDX12 0 #define NDX16 1 #define NDX32 2 #define fatconfig12 fatconfig[NDX12] #define fatconfig16 fatconfig[NDX16] #define fatconfig32 fatconfig[NDX32] /* JMP rel8 and NOP opcodes */ #define OPCODE_JMP_REL8 0xeb #define OPCODE_NOP 0x90 #define BOOTCODE_MSGOFFSET 29 /**************************************************************************** * Private Types ****************************************************************************/ struct fat_config_s { uint32_t fc_navailsects; /* The number of available sectors */ uint32_t fc_nfatsects; /* The number of sectors in one FAT */ uint32_t fc_nclusters; /* The number of clusters in the filesystem */ uint32_t fc_rsvdseccount; /* The number of reserved sectors */ }; /**************************************************************************** * Private Data ****************************************************************************/ /* Reverse engineered, generic boot message logic for non-bootable disk. * Message begins at offset 29; Sector relative offset must be poked into * offset 3. */ static uint8_t g_bootcodeblob[] = { 0x0e, 0x1f, 0xbe, 0x00, 0x7c, 0xac, 0x22, 0xc0, 0x74, 0x0b, 0x56, 0xb4, 0x0e, 0xbb, 0x07, 0x00, 0xcd, 0x10, 0x5e, 0xeb, 0xf0, 0x32, 0xe4, 0xcd, 0x16, 0xcd, 0x19, 0xeb, 0xfe, 0x54, 0x68, 0x69, 0x73, 0x20, 0x69, 0x73, 0x20, 0x6e, 0x6f, 0x74, 0x20, 0x61, 0x20, 0x62, 0x6f, 0x6f, 0x74, 0x61, 0x62, 0x6c, 0x65, 0x20, 0x64, 0x69, 0x73, 0x6b, 0x2e, 0x20, 0x20, 0x50, 0x6c, 0x65, 0x61, 0x73, 0x65, 0x20, 0x69, 0x6e, 0x73, 0x65, 0x72, 0x74, 0x20, 0x61, 0x20, 0x62, 0x6f, 0x6f, 0x74, 0x61, 0x62, 0x6c, 0x65, 0x20, 0x66, 0x6c, 0x6f, 0x70, 0x70, 0x79, 0x20, 0x61, 0x6e, 0x64, 0x0d, 0x0a, 0x70, 0x72, 0x65, 0x73, 0x73, 0x20, 0x61, 0x6e, 0x79, 0x20, 0x6b, 0x65, 0x79, 0x20, 0x74, 0x6f, 0x20, 0x74, 0x72, 0x79, 0x20, 0x61, 0x67, 0x61, 0x69, 0x6e, 0x20, 0x2e, 0x2e, 0x2e, 0x0d, 0x0a, 0x00 }; /**************************************************************************** * Private Functions ****************************************************************************/ /**************************************************************************** * Name: mkfatfs_nfatsect12 * * Description: * Calculate the number of sectors need for one fat in a FAT12 file system. * * Input: * fmt - Caller specified format parameters * var - Other format parameters that are not caller specifiable. (Most * set by mkfatfs_configfatfs()). * navailsects - The number of sectors available for both FAT and data. * This is a precalculated value equal to the total number of sectors * minus the number of root directory sectors and minus the number of * reserved sectors. * * Return: * 0: That calculation would have overflowed * >0: The size of one FAT in sectors. * ****************************************************************************/ static inline uint32_t mkfatfs_nfatsect12(FAR struct fat_format_s *fmt, FAR struct fat_var_s *var, uint32_t navailsects) { #ifdef CONFIG_HAVE_LONG_LONG uint64_t denom; uint64_t numer; #else uint32_t denom; uint32_t numer; #endif /* For FAT12, the cluster number is held in a 12-bit number or 1.5 bytes per * cluster reference. So each FAT sector will hold sectorsize/1.5 cluster * references (except for the first sector of each FAT which has two reserved * 12-bit values). And the total number of FAT sectors needed is: * * nfatsects = (1.5 * (ndataclust + 2) / sectorsize) * * where: * * ndataclust = ndatasect / clustsize * nvailsects = nfatsects + ndatasect * * The solution to this set of linear equations is: * * nfatsects = (3 * navailsects + 6 * clustersize) / * (3 * nfats + 2 * sectorsize * clustersize) * * The numerator would overflow uint32_t if: * * 3 * navailsects + 6 * clustersize > 0xffffffff * * Or * * navailsects > 0x55555555 - 2 * clustersize */ #ifndef CONFIG_HAVE_LONG_LONG if (navailsects <= (0x55555555 - (1 << (fmt->ff_clustshift + 1)))) { #endif denom = (fmt->ff_nfats << 1) + fmt->ff_nfats + (var->fv_sectorsize << (fmt->ff_clustshift + 1)); numer = (navailsects << 1) + navailsects + (1 << (fmt->ff_clustshift + 2)) + (1 << (fmt->ff_clustshift + 1)); return (uint32_t)((numer + denom - 1) / denom); #ifndef CONFIG_HAVE_LONG_LONG } else { return 0; } #endif } /**************************************************************************** * Name: mkfatfs_nfatsect16 * * Description: * Calculate the number of sectors need for one fat in a FAT16 file system. * * Input: * fmt - Caller specified format parameters * var - Other format parameters that are not caller specifiable. (Most * set by mkfatfs_configfatfs()). * navailsects - The number of sectors available for both FAT and data. * This is a precalculated value equal to the total number of sectors * minus the number of root directory sectors and minus the number of * reserved sectors. * * Return: * The size of one FAT in sectors. * ****************************************************************************/ static inline uint32_t mkfatfs_nfatsect16(FAR struct fat_format_s *fmt, FAR struct fat_var_s *var, uint32_t navailsects) { #ifdef CONFIG_HAVE_LONG_LONG uint64_t denom; uint64_t numer; #else uint32_t denom; uint32_t numer; #endif /* For FAT16, the cluster number is held in a 16-bit number or 2 bytes per * cluster reference. So each FAT sector will hold sectorsize/2 cluster * references (except for the first sector of each FAT which has two reserved * 16-bit values). And the total number of FAT sectors needed is: * * nfatsects = (2 * (ndataclust + 2) / sectorsize) * * where: * * ndataclust = ndatasect / clustsize * nvailsects = nfatsects + ndatasect * * The solution to this set of linear equations is: * * nfatsects = (navailsects + 2 * clustersize) / * (nfats + sectorsize * clustersize / 2) * * Overflow in the calculation of the numerator could occur if: * * navailsects > 0xffffffff - 2 * clustersize */ if (fmt->ff_clustshift == 0) { denom = fmt->ff_nfats + (var->fv_sectorsize >> 1); numer = navailsects + 2; } else { denom = fmt->ff_nfats + (var->fv_sectorsize << (fmt->ff_clustshift - 1)); numer = navailsects + (1 << (fmt->ff_clustshift + 1)); } return (uint32_t)((numer + denom - 1) / denom); } /**************************************************************************** * Name: mkfatfs_nfatsect32 * * Description: * Calculate the number of sectors need for one fat in a FAT32 file system. * * Input: * fmt - Caller specified format parameters * var - Other format parameters that are not caller specifiable. (Most * set by mkfatfs_configfatfs()). * navailsects - The number of sectors available for both FAT and data. * This is a precalculated value equal to the total number of sectors * minus the number of root directory sectors and minus the number of * reserved sectors. * * Return: * The size of one FAT in sectors. * ****************************************************************************/ static inline uint32_t mkfatfs_nfatsect32(FAR struct fat_format_s *fmt, FAR struct fat_var_s *var, uint32_t navailsects) { #ifdef CONFIG_HAVE_LONG_LONG uint64_t denom; uint64_t numer; #else uint32_t denom; uint32_t numer; #endif /* For FAT32, the cluster number is held in a 32-bit number or 4 bytes per * cluster reference. So each FAT sector will hold sectorsize/4 cluster * references (except for the first sector of each FAT which has three reserved * 32-bit values). And the total number of FAT sectors needed is: * * nfatsects = (4 * (ndataclust + 3) / sectorsize) * * where: * * ndataclust = ndatasect / clustsize * nvailsects = nfatsects + ndatasect * * The solution to this set of linear equations is: * * nfatsects = (navailsects + 3 * clustersize) / * (nfats + sectorsize * clustersize / 4) * * Overflow in the 32-bit calculation of the numerator could occur if: * * navailsects > 0xffffffff - 3 * clustersize */ if (fmt->ff_clustshift == 0) { denom = fmt->ff_nfats + (var->fv_sectorsize >> 2); numer = navailsects + 3; } else if (fmt->ff_clustshift == 1) { denom = fmt->ff_nfats + (var->fv_sectorsize >> 1); numer = navailsects + 6; } else { denom = fmt->ff_nfats + (var->fv_sectorsize << (fmt->ff_clustshift - 2)); numer = navailsects + (1 << (fmt->ff_clustshift + 1)) + (1 << fmt->ff_clustshift); } return (uint32_t)((numer + denom - 1) / denom); } /**************************************************************************** * Name: mkfatfs_clustersearchlimits * * Description: * Pick the starting and ending cluster size to use in the search for the * the optimal cluster size. * * Input: * fmt - Caller specified format parameters * var - Other format parameters that are not caller specifiable. (Most * set by mkfatfs_configfatfs()). * * Return: * Starting cluster size is set in fmt->ff_clustshift; Final cluster * size is the returned value. * ****************************************************************************/ static inline uint8_t mkfatfs_clustersearchlimits(FAR struct fat_format_s *fmt, FAR struct fat_var_s *var) { uint8_t mxclustshift; /* Did the caller already pick the cluster size? If not, the clustshift value * will be 0xff */ if (fmt->ff_clustshift == 0xff) { /* Pick a starting size based on the number of sectors on the device */ if (fmt->ff_nsectors < 2048) { /* 2k sectors, start wit 1 sector/cluster. */ fmt->ff_clustshift = 0; } else if (fmt->ff_nsectors < 4096) { /* 4k sectors, start with 2 sector/cluster. */ fmt->ff_clustshift = 1; } else if (fmt->ff_nsectors < 8192) { /* 8k sectors, start with 4 sector/cluster. */ fmt->ff_clustshift = 2; } else if (fmt->ff_nsectors < 16384) { /* 16k sectors, start with 8 sector/cluster. */ fmt->ff_clustshift = 3; } else if (fmt->ff_nsectors < 32768) { /* 32k sectors, start with 16 sector/cluster. */ fmt->ff_clustshift = 4; } else { /* Otherwise, 32 sector/cluster. */ fmt->ff_clustshift = 5; } /* Wherever the search starts, it will end with the maximum of * 128 sectors per cluster */ mxclustshift = 7; } else { /* The caller has selected a cluster size. There will be no search! * Just set the maximum to the caller specificed value. */ mxclustshift = fmt->ff_clustshift; } return mxclustshift; } /**************************************************************************** * Name: mkfatfs_tryfat12 * * Description: * Try to define a FAT12 filesystem on the device using the candidate * sectors per cluster * * Input: * fmt - Caller specified format parameters * var - Other format parameters that are not caller specifiable. (Most * set by mkfatfs_configfatfs()). * config - FAT12-specific configuration * * Return: * Zero on success configuration of a FAT12 file system; negated errno * on failure * ****************************************************************************/ static inline int mkfatfs_tryfat12(FAR struct fat_format_s *fmt, FAR struct fat_var_s *var, FAR struct fat_config_s *config) { uint32_t maxnclusters; /* Calculate the number sectors in one FAT required to access all of the * available sectors. */ config->fc_nfatsects = mkfatfs_nfatsect12(fmt, var, config->fc_navailsects); if (config->fc_nfatsects > 0) { /* Calculate the number of clusters available given the number of available * sectors and the number of those that will be used for FAT: */ config->fc_nclusters = (config->fc_navailsects - fmt->ff_nfats * config->fc_nfatsects) >> fmt->ff_clustshift; /* Calculate the maximum number of clusters that could be supported by a * FAT of this size. * * maxnclusters = nfatsects * sectorsize / 1.5 - 2 */ maxnclusters = (config->fc_nfatsects << (var->fv_sectshift + 1)) / 3; if (maxnclusters > FAT_MAXCLUST12) { maxnclusters = FAT_MAXCLUST12; } fvdbg("nfatsects=%u nclusters=%u (max=%u)\n", config->fc_nfatsects, config->fc_nclusters, maxnclusters); /* Check if this number of clusters would overflow the maximum for * FAT12 (remembering that two FAT cluster slots are reserved). */ if (config->fc_nclusters + 2 > maxnclusters) { fdbg("Too many clusters for FAT12: %d > %d\n", config->fc_nclusters, maxnclusters - 2); return -ENFILE; } } return 0; } /**************************************************************************** * Name: mkfatfs_tryfat16 * * Description: * Try to define a FAT16 filesystem on the device using the candidate * sectors per cluster * * Input: * fmt - Caller specified format parameters * var - Other format parameters that are not caller specifiable. (Most * set by mkfatfs_configfatfs()). * config - FAT16-specific configuration * * Return: * Zero on success configuration of a FAT16 file system; negated errno * on failure * ****************************************************************************/ static inline int mkfatfs_tryfat16(FAR struct fat_format_s *fmt, FAR struct fat_var_s *var, FAR struct fat_config_s *config) { uint32_t maxnclusters; /* Calculate the number sectors in one FAT required to access all of the * available sectors. */ config->fc_nfatsects = mkfatfs_nfatsect16(fmt, var, config->fc_navailsects); if (config->fc_nfatsects > 0) { /* Calculate the number of clusters available given the number of available * sectors and the number of those that will be used for FAT: */ config->fc_nclusters = (config->fc_navailsects - fmt->ff_nfats * config->fc_nfatsects) >> fmt->ff_clustshift; /* Calculate the maximum number of clusters that could be supported by a * FAT of this size. * * maxnclusters = nfatsects * sectorsize / 2 - 2 */ maxnclusters = config->fc_nfatsects << (var->fv_sectshift - 1); if (maxnclusters > FAT_MAXCLUST16) { maxnclusters = FAT_MAXCLUST16; } fvdbg("nfatsects=%u nclusters=%u (min=%u max=%u)\n", config->fc_nfatsects, config->fc_nclusters, FAT_MINCLUST16, maxnclusters); /* Check if this number of clusters would overflow the maximum for * FAT16 (remembering that two FAT cluster slots are reserved). * Check the lower limit as well. The FAT12 is distinguished from FAT16 * by comparing the number of clusters on the device agains a known * threshold. If a small FAT16 file system were created, then it would * be confused as a FAT12 at mount time. */ if ((config->fc_nclusters + 2 > maxnclusters) || (config->fc_nclusters < FAT_MINCLUST16)) { fdbg("Too few or too many clusters for FAT16: %d < %d < %d\n", FAT_MINCLUST16, config->fc_nclusters, maxnclusters - 2); return -ENFILE; } } return 0; } /**************************************************************************** * Name: mkfatfs_tryfat32 * * Description: * Try to define a FAT32 filesystem on the device using the candidate * sectors per cluster * * Input: * fmt - Caller specified format parameters * var - Other format parameters that are not caller specifiable. (Most * set by mkfatfs_configfatfs()). * config - FAT32-specific configuration * * Return: * Zero on success configuration of a FAT32 file system; negated errno * on failure * ****************************************************************************/ static inline int mkfatfs_tryfat32(FAR struct fat_format_s *fmt, FAR struct fat_var_s *var, FAR struct fat_config_s *config) { uint32_t maxnclusters; /* Calculate the number sectors in one FAT required to access all of the * available sectors. */ config->fc_nfatsects = mkfatfs_nfatsect32(fmt, var, config->fc_navailsects); if (config->fc_nfatsects > 0) { /* Calculate the number of clusters available given the number of available * sectors and the number of those that will be used for FAT: */ config->fc_nclusters = (config->fc_navailsects - fmt->ff_nfats * config->fc_nfatsects) >> fmt->ff_clustshift; /* Calculate the maximum number of clusters that could be supported by a * FAT of this size. * * maxnclusters = nfatsects * sectorsize / 4 - 2 */ maxnclusters = (config->fc_nfatsects << (var->fv_sectshift - 2)); if (maxnclusters > FAT_MAXCLUST32) { maxnclusters = FAT_MAXCLUST32; } fvdbg("nfatsects=%u nclusters=%u (max=%u)\n", config->fc_nfatsects, config->fc_nclusters, maxnclusters); /* Check if this number of clusters would overflow the maximum for * FAT32 (remembering that two FAT cluster slots are reserved). */ if ((config->fc_nclusters + 3 > maxnclusters) || (config->fc_nclusters < FAT_MINCLUST32)) { fdbg("Too few or too many clusters for FAT32: %d < %d < %d\n", FAT_MINCLUST32, config->fc_nclusters, maxnclusters - 3); return -ENFILE; } } return 0; } /**************************************************************************** * Name: mkfatfs_selectfat * * Description: * The cluster search has succeeded, select the specified FAT FS * * Input: * fattype - The FAT size selected * fmt - Caller specified format parameters * var - Format parameters that are not caller specifiable. * * Return: * None * ****************************************************************************/ static inline void mkfatfs_selectfat(int fattype, FAR struct fat_format_s *fmt, FAR struct fat_var_s *var, FAR struct fat_config_s *config) { /* Return the appropriate information about the selected file system. */ fvdbg("Selected FAT%d\n", fattype); var->fv_fattype = fattype; var->fv_nclusters = config->fc_nclusters; var->fv_nfatsects = config->fc_nfatsects; fmt->ff_rsvdseccount = config->fc_rsvdseccount; } /**************************************************************************** * Name: mkfatfs_clustersearch * * Description: * Search to find the smallest (reasonable) cluster size for the FAT file * system. * * Input: * fmt - Caller specified format parameters * var - Other format parameters that are not caller specifiable. (Most * set by mkfatfs_configfatfs()). * * Return: * Zero on success; negated errno on failure * ****************************************************************************/ static inline int mkfatfs_clustersearch(FAR struct fat_format_s *fmt, FAR struct fat_var_s *var) { struct fat_config_s fatconfig[3]; uint8_t mxclustshift; memset(fatconfig, 0, 3*sizeof(struct fat_config_s)); /* Select the reserved sector count for each FAT size */ if (fmt->ff_rsvdseccount) { fatconfig12.fc_rsvdseccount = fmt->ff_rsvdseccount; fatconfig16.fc_rsvdseccount = fmt->ff_rsvdseccount; if (fmt->ff_rsvdseccount < 2) { fdbg("At least 2 reserved sectors needed by FAT32\n"); fatconfig32.fc_rsvdseccount = 2; } else { fatconfig32.fc_rsvdseccount = fmt->ff_rsvdseccount; } } else { fatconfig12.fc_rsvdseccount = 1; fatconfig16.fc_rsvdseccount = 1; fatconfig32.fc_rsvdseccount = 32; } /* Determine the number of sectors needed by the root directory. * This is a constant value, independent of cluster size for FAT12/16 */ if (var->fv_fattype != 32) { /* Calculate the number of sectors reqired to contain the selected * number of root directory entries. This value is save in the var * structure but will be overwritten if FAT32 is selected. FAT32 uses * a cluster chain for the root directory, so the concept of the number * of root directory entries does not apply to FAT32 */ var->fv_nrootdirsects = ((fmt->ff_rootdirentries << DIR_SHIFT) + var->fv_sectorsize - 1) >> var->fv_sectshift; /* The number of data sectors available (includes the fat itself) * This value is a constant for FAT12/16, but not FAT32 because the * size of the root directory cluster changes */ fatconfig12.fc_navailsects = fatconfig16.fc_navailsects = fmt->ff_nsectors - var->fv_nrootdirsects - fatconfig12.fc_rsvdseccount; } /* Select an initial and terminal cluster size to use in the search (if these * values were not provided by the caller) */ mxclustshift = mkfatfs_clustersearchlimits(fmt, var); do { fvdbg("Configuring with %d sectors/cluster...\n", 1 << fmt->ff_clustshift); /* Check if FAT12 has not been excluded */ if (var->fv_fattype == 0 || var->fv_fattype == 12) { /* Try to configure a FAT12 file system with this cluster size */ if (mkfatfs_tryfat12(fmt, var, &fatconfig12) != 0) { fdbg("Cannot format FAT12 at %u sectors/cluster\n", 1 << fmt->ff_clustshift); fatconfig12.fc_nfatsects = 0; fatconfig12.fc_nclusters = 0; } } /* Check if FAT16 has not been excluded */ if (var->fv_fattype == 0 || var->fv_fattype == 16) { /* Try to configure a FAT16 file system with this cluster size */ if (mkfatfs_tryfat16(fmt, var, &fatconfig16) != 0) { fdbg("Cannot format FAT16 at %u sectors/cluster\n", 1 << fmt->ff_clustshift); fatconfig16.fc_nfatsects = 0; fatconfig16.fc_nclusters = 0; } } /* If either FAT12 or 16 was configured at this sector/cluster setting, * then finish the configuration and break out now */ if (fatconfig12.fc_nclusters || fatconfig16.fc_nclusters) { if ((!var->fv_fattype && fatconfig16.fc_nclusters > fatconfig12.fc_nclusters) || (var ->fv_fattype == 16)) { /* The caller has selected FAT16 -OR- no FAT type has been selected, but * the FAT16 selection has more clusters. Select FAT16. */ mkfatfs_selectfat(16, fmt, var, &fatconfig16); } else { /* The caller has selected FAT12 -OR- no FAT type has been selected, but * the FAT12 selected has more clusters. Selected FAT12 */ mkfatfs_selectfat(12, fmt, var, &fatconfig12); } return OK; } #if 0 /* Check if FAT32 has not been excluded */ if (var->fv_fattype == 0 || var->fv_fattype == 32) #else /* FAT32 must be explicitly requested */ if (var->fv_fattype == 32) #endif { /* The number of data sectors available (includes the fat itself) * This value is a constant with respect to cluster sizefor FAT12/16, but not FAT32 * because the size of the root directory cluster changes with cluster size. */ fatconfig32.fc_navailsects = fmt->ff_nsectors - (1 << fmt->ff_clustshift) - fatconfig32.fc_rsvdseccount; /* Try to configure a FAT32 file system with this cluster size */ if (mkfatfs_tryfat32(fmt, var, &fatconfig32) != 0) { fdbg("Cannot format FAT32 at %u sectors/cluster\n", 1 << fmt->ff_clustshift); fatconfig32.fc_nfatsects = 0; fatconfig32.fc_nclusters = 0; } else { /* Select FAT32 if we have not already done so */ mkfatfs_selectfat(32, fmt, var, &fatconfig32); return OK; } } /* Otherwise, bump up the sectors/cluster for the next time around the loop. */ fmt->ff_clustshift++; } while (fmt->ff_clustshift <= mxclustshift); return -ENFILE; } /**************************************************************************** * Global Functions ****************************************************************************/ /**************************************************************************** * Name: mkfatfs_configfatfs * * Description: * Based on the geometry of the block device and upon the caller-selected * values, configure the FAT filesystem for the device. * * Input: * fmt - Caller specified format parameters * var - Holds disk geomtry data. Also, the location to return FAT * configuration data * * Return: * Zero on success; negated errno on failure * ****************************************************************************/ int mkfatfs_configfatfs(FAR struct fat_format_s *fmt, FAR struct fat_var_s *var) { int ret; /* Select the number of root directory entries (FAT12/16 only). If FAT32 is selected, * this value will be cleared later */ if (!fmt->ff_rootdirentries) { /* The caller did not specify the number of root directory entries; use a default of 512. */ fmt->ff_rootdirentries = 512; } /* Search to determine the smallest (reasonable) cluster size. A by-product * of this search will be the selection of the FAT size (12/16/32) if the * caller has not specified the FAT size */ ret = mkfatfs_clustersearch(fmt, var); if (ret < 0) { fdbg("ERROR: Failed to set cluster size\n"); return ret; } /* Perform FAT specific initialization */ /* Set up boot jump assuming FAT 12/16 offset to bootcode */ var->fv_jump[0] = OPCODE_JMP_REL8; var->fv_jump[2] = OPCODE_NOP; var->fv_bootcode = g_bootcodeblob; var->fv_bootcodesize = sizeof(g_bootcodeblob); if (var->fv_fattype != 32) { /* Set up additional, non-zero FAT12/16 fields */ /* Patch in the correct offset to the boot code */ var->fv_jump[1] = BS16_BOOTCODE - 2; g_bootcodeblob[3] = BS16_BOOTCODE + BOOTCODE_MSGOFFSET; } else { /* Patch in the correct offset to the boot code */ var->fv_jump[1] = BS32_BOOTCODE - 2; g_bootcodeblob[3] = BS32_BOOTCODE + BOOTCODE_MSGOFFSET; /* The root directory is a cluster chain... its is initialize size is one cluster */ var->fv_nrootdirsects = 1 << fmt->ff_clustshift; /* The number of reported root directory entries should should be zero for * FAT32 because the root directory is a cluster chain. */ fmt->ff_rootdirentries = 0; /* Verify the caller's backupboot selection */ if (fmt->ff_backupboot <= 1 || fmt->ff_backupboot >= fmt->ff_rsvdseccount) { fdbg("Invalid backup boot sector: %d\n", fmt->ff_backupboot); fmt->ff_backupboot = 0; } /* Check if the caller has selected a location for the backup boot record */ if (!fmt->ff_backupboot) { /* There must be reserved sectors in order to have a backup boot sector */ if (fmt->ff_rsvdseccount > 0 && fmt->ff_rsvdseccount >= 2) { /* Sector 0 is the MBR; 1... ff_rsvdseccount are reserved. Try the next * the last reserved sector. */ fmt->ff_backupboot = fmt->ff_rsvdseccount - 1; if (fmt->ff_backupboot > 6) { /* Limit the location to within the first 7 */ fmt->ff_backupboot = 6; } } } } /* Report the selected fat type */ fmt->ff_fattype = var->fv_fattype; /* Describe the configured filesystem */ #ifdef CONFIG_DEBUG fdbg("Sector size: %d bytes\n", var->fv_sectorsize); fdbg("Number of sectors: %d sectors\n", fmt->ff_nsectors); fdbg("FAT size: %d bits\n", var->fv_fattype); fdbg("Number FATs: %d\n", fmt->ff_nfats); fdbg("Sectors per cluster: %d sectors\n", 1 << fmt->ff_clustshift); fdbg("FS size: %d sectors\n", var->fv_nfatsects); fdbg(" %d clusters\n", var->fv_nclusters); if (var->fv_fattype != 32) { fdbg("Root directory slots: %d\n", fmt->ff_rootdirentries); } fdbg("Volume ID: %08x\n", fmt->ff_volumeid); fdbg("Volume Label: \"%c%c%c%c%c%c%c%c%c%c%c\"\n", fmt->ff_volumelabel[0], fmt->ff_volumelabel[1], fmt->ff_volumelabel[2], fmt->ff_volumelabel[3], fmt->ff_volumelabel[4], fmt->ff_volumelabel[5], fmt->ff_volumelabel[6], fmt->ff_volumelabel[7], fmt->ff_volumelabel[8], fmt->ff_volumelabel[9], fmt->ff_volumelabel[10]); #endif return OK; }