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Diffstat (limited to 'nuttx/fs/fat/fs_configfat.c')
-rw-r--r-- | nuttx/fs/fat/fs_configfat.c | 963 |
1 files changed, 963 insertions, 0 deletions
diff --git a/nuttx/fs/fat/fs_configfat.c b/nuttx/fs/fat/fs_configfat.c new file mode 100644 index 000000000..9ec7573a7 --- /dev/null +++ b/nuttx/fs/fat/fs_configfat.c @@ -0,0 +1,963 @@ +/**************************************************************************** + * fs/fat/fs_configfat.c + * + * Copyright (C) 2008-2009 Gregory Nutt. All rights reserved. + * Author: Gregory Nutt <spudmonkey@racsa.co.cr> + * + * 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 <nuttx/config.h> + +#include <stdint.h> +#include <string.h> +#include <debug.h> +#include <errno.h> + +#include <nuttx/fs.h> +#include <nuttx/fat.h> +#include <nuttx/mkfatfs.h> + +#include "fs_internal.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_try12 + * + * 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()). + * fatconfig - 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 > maxnclusters - 2) + { + fvdbg("Too many clusters for FAT12\n"); + return -ENFILE; + } + } + return 0; +} + +/**************************************************************************** + * Name: mkfatfs_try16 + * + * 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()). + * fatconfig - 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_sectorsize - 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 > maxnclusters - 2) || + (config->fc_nclusters < FAT_MINCLUST16)) + { + fvdbg("Too few or too many clusters for FAT16\n"); + return -ENFILE; + } + } + return 0; +} + +/**************************************************************************** + * Name: mkfatfs_try32 + * + * 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()). + * fatconfig - 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 > maxnclusters - 3) || + (config->fc_nclusters < FAT_MINCLUST32 && fmt->ff_fattype != 32)) + { + fvdbg("Too few or too many clusters for FAT32\n"); + 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. */ + + fdbg("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) + { + fvdbg("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 clustersize 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 filesystem with this cluster size */ + + if (mkfatfs_tryfat12(fmt, var, &fatconfig12) != 0) + { + { + fvdbg("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 filesystem with this cluster size */ + + if (mkfatfs_tryfat16(fmt, var, &fatconfig16) != 0) + { + { + fvdbg("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; + } + + /* Check if FAT32 has not been excluded */ + + if (var->fv_fattype == 0 || var->fv_fattype == 32) + { + /* 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 filesystem with this cluster size */ + + if (mkfatfs_tryfat32(fmt, var, &fatconfig32) != 0) + { + { + fvdbg("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("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; +} + |