FAT32code.zip

/*C************************************************************************** * NAME: fat32.c *---------------------------------------------------------------------------- * Copyright (c) 2003 Atmel. *---------------------------------------------------------------------------- * RELEASE: snd1c-refd-nf-4_0_3 * REVISION: 1.4 *---------------------------------------------------------------------------- * PURPOSE: * FAT32 file-system basics functions * * NOTES: * Supports only the first partition * Supports only 512 bytes sector size * Supports only file fragmentation < MAX_FILE_FRAGMENT_NUMBER * Supports only one file openned at a time * * Global Variables: * - gl_buffer: array of bytes in pdata space *****************************************************************************/ /*_____ I N C L U D E S ____________________________________________________*/ #include "config.h" /* system configuration */ #include "..\mem\hard.h" /* low level function definition */ #include "file.h" /* file function definition */ #include "fat32.h" /* fat32 file-system definition */ /*_____ M A C R O S ________________________________________________________*/ /*_____ D E F I N I T I O N ________________________________________________*/ extern pdata Byte gl_buffer[]; extern char pdata *lfn_name; /* long filename limited to MAX_FILENAME_LEN chars */ extern xdata Byte fat_buf_sector[]; /* 512 bytes buffer */ /* disk management */ extern data Uint32 fat_ptr_fats; /* address of the first byte of FAT */ extern data Uint32 fat_ptr_data; /* address of the first byte of data */ extern data Byte fat_cluster_size; /* cluster size (sector count) */ extern idata Byte fat_cluster_mask; /* mask for end of cluster test */ extern bdata bit dir_is_root; /* TRUE: point the root directory */ extern bdata bit fat_is_fat16; /* TRUE: FAT16 - FALSE: FAT12 */ extern bdata bit fat_is_fat32; /* TRUE: FAT32 - FALSE: FAT12/FAT16 */ extern bdata bit fat_open_mode; /* READ or WRITE */ extern bdata bit fat_2_is_present; /* TRUE: 2 FATs - FALSE: 1 FAT */ extern bdata bit flag_end_disk_file; extern xdata Uint32 fat_count_of_clusters;/* number of cluster - 2 */ extern xdata Union32 fat_file_size; extern xdata Uint32 fat_fat_size; /* FAT size in sector count */ /* directory management */ extern xdata fat_st_clust_chain dclusters[MAX_DIR_FRAGMENT_NUMBER]; /* cluster chain for the current directory */ extern idata Uint16 fat_dclust_byte_count;/* byte counter in directory sector */ extern idata Uint16 fat_dchain_index; /* the number of the fragment of the dir, in fact the index of the table in the cluster chain */ extern idata Byte fat_dchain_nb_clust; /* the offset of the cluster from the first cluster of the dir fragment */ extern xdata Byte fat_last_dclust_index;/* index of the last cluster in directory chain */ extern xdata Uint16 fat_dir_list_index; /* index of current entry in dir list */ extern xdata Uint16 fat_dir_list_last; /* index of last entry in dir list */ extern xdata Uint32 fat_dir_start_sect; /* start sector of dir list */ extern idata Uint32 fat_dir_current_sect; /* sector of selected entry in dir list */ extern xdata Uint32 fat_dir_current_offs; /* entry offset from fat_dir_current_sect */ extern xdata fat_st_cache fat_cache; /* The cache structure, see the .h for more info */ extern xdata char ext[3]; /* file extension (limited to 3 characters) */ /* file management */ extern xdata fat_st_clust_chain fclusters[MAX_FILE_FRAGMENT_NUMBER]; /* cluster chain for the current file */ extern idata Byte fat_last_clust_index; /* index of the last cluster in file chain */ extern data Uint16 fat_fclust_byte_count;/* byte counter in file cluster */ extern idata Byte fat_fchain_index; /* the number of the fragment of the file, in fact the index of the table in the cluster chain */ extern idata Uint16 fat_fchain_nb_clust; /* the offset of the cluster from the first cluster of the file fragment */ extern xdata Uint32 fat_current_file_size; extern xdata Uint32 fat_rootclus_fat32; /* root cluster address */ extern bdata bit fat_last_dir_cluster_full; extern bdata bit fat_no_entries_free; extern xdata Uint16 fat_total_clusters; extern xdata Uint32 last_free_cluster; /* Mode repeat A/B variables */ extern xdata Byte fat_fchain_index_save; extern xdata Byte fat_fchain_nb_clust_save; extern xdata Uint16 fat_fclust_byte_count_save; extern xdata Byte current_ext; extern idata Uint16 fat_current_end_entry_position; extern idata Uint16 fat_current_start_entry_position; extern xdata Uint16 fat_nb_deleted_entries; extern xdata Uint16 fat_nb_total_entries; /*_____ D E C L A R A T I O N ______________________________________________*/ static void fat_get_dir_entry (fat_st_dir_entry xdata *); static void fat_get_dir_file_list (Byte); static bit fat_get_clusters (fat_st_clust_chain xdata *, Byte); static bit fat_get_free_clusters (bit); static bit fat_dseek (Int16); static Byte fat_dgetc (void); /*F************************************************************************** * NAME: fat_install *---------------------------------------------------------------------------- * PARAMS: * * return: * - OK: intallation succeeded * - KO: - partition 1 not active * - FAT type is not FAT16 * - sector size is not 512 bytes * - MBR or PBR signatures are not correct * - low level read open failure *---------------------------------------------------------------------------- * PURPOSE: * Install the fat system, read mbr, bootrecords... *---------------------------------------------------------------------------- * EXAMPLE: *---------------------------------------------------------------------------- * NOTE: * if MBR not found, try to mount unpartitionned FAT * sector size is fixed to 512 bytes to simplify low level drivers * fat_ptr_fats = partition offset + nb_reserved_sector *---------------------------------------------------------------------------- * REQUIREMENTS: *****************************************************************************/ bit fat_install (void) { Byte i; Uint32 tot_sect; Uint32 fat_nb_sector; Uint16 bpb_rsvd_sec_cnt; Byte bpb_num_fat; Uint16 bpb_root_ent_count; /* read and check usefull MBR info */ /* go to the first partition field */ Hard_read_open(MBR_ADDRESS); Hard_load_sector(); Hard_read_close(); fat_ptr_fats = 0x01; if ((fat_buf_sector[0] == 0xEB) && (fat_buf_sector[2] == 0x90)) /* Jump instruction to boot code */ { if ((fat_buf_sector[21] & 0xF0) == 0xF0) /* Media byte */ { if ((fat_buf_sector[510] == 0x55) && (fat_buf_sector[511] == 0xAA)) /* signature */ { fat_ptr_fats = 0x00000000; /* disk may not be partitionned : first sector */ } /* is PBR */ else { return KO; /* no signature -> low level error */ } } } if (fat_ptr_fats) /* if first sector is not a PBR */ { if (Hard_read_open(MBR_ADDRESS) == OK) { for (i = 446/2; i != 0; i--) { Hard_read_byte();