diff options
Diffstat (limited to 'firmware/test/fat/fat-bpb_sector.h')
| -rw-r--r-- | firmware/test/fat/fat-bpb_sector.h | 211 |
1 files changed, 211 insertions, 0 deletions
diff --git a/firmware/test/fat/fat-bpb_sector.h b/firmware/test/fat/fat-bpb_sector.h new file mode 100644 index 0000000000..247f53115c --- /dev/null +++ b/firmware/test/fat/fat-bpb_sector.h @@ -0,0 +1,211 @@ +/*************************************************************************** + * __________ __ ___. + * Open \______ \ ____ ____ | | _\_ |__ _______ ___ + * Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ / + * Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < < + * Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \ + * \/ \/ \/ \/ \/ + * $Id$ + * + * Copyright (C) 2002 by Alan Korr + * + * All files in this archive are subject to the GNU General Public License. + * See the file COPYING in the source tree root for full license agreement. + * + * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY + * KIND, either express or implied. + * + ****************************************************************************/ +#ifndef __LIBRARY_FAT_BPB_SECTOR_H__ +#define __LIBRARY_FAT_BPB_SECTOR_H__ + +// [Alan]: +// I would like to draw your attention about the fact that SH1 +// cannot use misaligned address access so you must be very cautious +// with structures stored in FAT32 partition because they come from +// PC world where misaligned address accesses are usual and not +// problematic. To avoid such a trouble, I decide to use special +// structures where fields are moved in such a way they can be +// accessed by SH1. It is possible thanks to the callback mechanism +// I use for reading or writing from/to an ATA device in ata.h/c. +// So don't be puzzled if those structures seem odd compared +// with the usual ones from PC world. I use this mechanism for structures +// 'partition_info', 'mbr_sector' and 'fsi_sector' for instance, but +// not for structure 'bpb_sector' which is too much complex to handle +// that way, I think. +// By the way, SH1 is big endian, not little endian as PC is. + +/////////////////////////////////////////////////////////////////////////////////// +// BPB SECTOR : +/////////////// +// +// + +struct __fat_bpb_sector /* Bios Parameters Block Sector */ + { + // jmp_boot has two valid ways to look like in a FAT BPB. + // Either EBXX90 or E9XXXX. + // Not used by Rockbox. + unsigned char + jmp_boot[3]; + + // Creator system of the fat-drive. + // Usually looks like "MSWIN4.x". + char + oem_name[8]; + + // It should be 512 if you don't want any trouble + // with Rockbox firmware. + unsigned char + bytes_per_sector[2]; + + // Must be a power of two. + unsigned char + sectors_per_cluster[1]; + + // Number of reserved sectors in the reserved region of the volume + // starting at the first sector of the volume. + // Usually 32 for FAT32. + unsigned char + reserved_sectors[2]; + + // Number of FAT structures. + // This value should always be 2. + unsigned char + number_of_fats[1]; + + // For FAT32, this field must be set to zero. + // Not used by Rockbox. + unsigned char + number_of_root_entries[2]; + + // Must be zero for FAT32, since the real value + // can be found in total_sectors. + // Not used by Rockbox. + unsigned char + total_sectors_16[2]; + + // Not used by Rockbox. + unsigned char + media[1]; + + // In FAT32 this must be zero. + // Not used by Rockbox. + unsigned char + sectors_per_fat_16[2]; + + // Sectors per track used on this media. + // Not used by Rockbox. + unsigned char + sectors_per_track[2]; + + // Number of heads used on this media. + // Not used by Rockbox. + unsigned char + number_of_heads[2]; + + // Number of hidden sectors. + // Not used by Rockbox. + unsigned char + hidden_sectors[4]; + + // Number of total sectors. + // For FAT32 volumes, this must be specified. + unsigned char + total_sectors[4]; + + // Here follows FAT12/16 or FAT32 specific data. */ + + // This is the number of sectors for one FAT. + unsigned char + sectors_per_fat[4]; + + // Extended FAT32 flags follow. + unsigned char + flags[2]; + // bits 15-8: reserved + // mirroring, bit 7: + // 0 -> FAT is mirrored at runtime into all FATs. + // 1 -> only the one specified in the following field + // is active. + // Rockbox always sets it. + // bits 7-4 : reserved + // active_fat, bits 3-0: + // this specifies the "active" FAT mentioned previously. + + // This specifies the file system version. + // High byte is major number, low byte is minor. + // The current version is 0.0. + unsigned char + filesystem_version[2]; + + // This is set to the cluster number of the first cluster + // of the root directory. Usually 2, but not required. + unsigned char + root_cluster[4]; + + // This specifies the sector number of the 'FSINFO' structure + // in the reserved area. + unsigned char + filesystem_info[2]; + + // If zero, this specifies where the backup of bpb + // can be found. + // Usually 6. + // No value other than 6 is recommended by Microsoft. + unsigned char + backup_bpb[2]; + + // The following area should always be set to zero + // when the volume is initialised. + unsigned char + zeros[12]; + + // Drive number for BIOS. + // Not used by Rockbox. + unsigned char + drive_number[0]; + + // Reserved for Windows NT. + // Should always be set to 0. + unsigned char + reserved_for_nt[0]; + + // Extended boot signature. + // If this is 0x29, the following three fields are present. + unsigned char + boot_signature[0]; + + // Volume serial number. + unsigned char + volume_id[4]; + + // Volume label. + // This field must be updated when the volume label + // in the root directory is updated. + char + volume_label[11]; + + // One of the strings "FAT12", "FAT16" or "FAT32". + // This can not be used to determine the type of the FAT, + // but it should be updated when creating file systems. + char + filesystem_type[8]; + + char + reserved[420]; + + long + signature; + }; + +static inline int __fat_get_bpb_sector (unsigned long partition_start,unsigned long lba,struct __fat_bpb_sector *bpb_sector) + { return ata_read_sectors (partition_start + lba,1,bpb_sector,0); } + +static inline int __fat_put_bpb_sector (unsigned long partition_start,unsigned long lba,struct __fat_bpb_sector *bpb_sector) + { return FAT_RETURN_SUCCESS && ata_write_sectors (partition_start + lba,1,bpb_sector,0); } + +// +/////////////////////////////////////////////////////////////////////////////////// + +#endif
\ No newline at end of file |