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Update fat.c
This commit is contained in:
RocketRobz
parent
c96b8e1855
commit
4cabc9d09f
@ -75,12 +75,9 @@ License:
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#define __PACKED __attribute__ ((__packed__))
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// Boot Sector - must be packed
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typedef struct
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{
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u8 jmpBoot[3];
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u8 OEMName[8];
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// BIOS Parameter Block
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// BIOS Parameter Block
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typedef struct {
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u16 bytesPerSector;
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u8 sectorsPerCluster;
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u16 reservedSectors;
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@ -93,6 +90,14 @@ typedef struct
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u16 numHeads;
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u32 numHiddenSectors;
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u32 numSectors;
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} __PACKED BIOS_BPB;
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// Boot Sector - must be packed
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typedef struct
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{
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u8 jmpBoot[3];
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u8 OEMName[8];
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BIOS_BPB bpb;
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union // Different types of extended BIOS Parameter Block for FAT16 and FAT32
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{
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struct
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@ -106,7 +111,7 @@ typedef struct
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u8 fileSysType[8];
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// Bootcode
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u8 bootCode[448];
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} fat16;
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} __PACKED fat16;
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struct
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{
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// FAT32 extended block
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@ -126,13 +131,15 @@ typedef struct
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u8 fileSysType[8];
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// Bootcode
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u8 bootCode[420];
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} fat32;
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} extBlock;
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} __PACKED fat32;
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} __PACKED extBlock;
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__PACKED u16 bootSig;
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} __PACKED BOOT_SEC;
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_Static_assert(sizeof(BOOT_SEC) == 512);
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// Directory entry - must be packed
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typedef struct
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{
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@ -251,8 +258,7 @@ u32 FAT_NextCluster(u32 cluster)
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// read the nextCluster value
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nextCluster = ((u16*)globalBuffer)[offset];
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if (nextCluster >= 0xFFF7)
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{
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if (nextCluster >= 0xFFF7) {
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nextCluster = CLUSTER_EOF;
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}
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break;
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@ -265,8 +271,7 @@ u32 FAT_NextCluster(u32 cluster)
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// read the nextCluster value
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nextCluster = (((u32*)globalBuffer)[offset]) & 0x0FFFFFFF;
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if (nextCluster >= 0x0FFFFFF7)
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{
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if (nextCluster >= 0x0FFFFFF7) {
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nextCluster = CLUSTER_EOF;
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}
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break;
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@ -304,8 +309,7 @@ bool FAT_InitFiles (bool initCard)
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int bootSector;
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BOOT_SEC* bootSec;
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if (initCard && !CARD_StartUp())
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{
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if (initCard && !CARD_StartUp()) {
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return (false);
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}
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@ -314,17 +318,10 @@ bool FAT_InitFiles (bool initCard)
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{
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return false;
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}
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// Check if there is a FAT string, which indicates this is a boot sector
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if ((globalBuffer[0x36] == 'F') && (globalBuffer[0x37] == 'A') && (globalBuffer[0x38] == 'T'))
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{
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if (((globalBuffer[0x36] == 'F') && (globalBuffer[0x37] == 'A') && (globalBuffer[0x38] == 'T')) // Check if there is a FAT string, which indicates this is a boot sector
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|| ((globalBuffer[0x52] == 'F') && (globalBuffer[0x53] == 'A') && (globalBuffer[0x54] == 'T'))) { // Check for FAT32
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bootSector = 0;
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}
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// Check for FAT32
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else if ((globalBuffer[0x52] == 'F') && (globalBuffer[0x53] == 'A') && (globalBuffer[0x54] == 'T'))
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{
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bootSector = 0;
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}
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else // This is an MBR
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} else // This is an MBR
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{
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// Find first valid partition from MBR
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// First check for an active partition
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@ -334,7 +331,7 @@ bool FAT_InitFiles (bool initCard)
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for (i=0x1BE; (i < 0x1FE) && (globalBuffer[i+0x04] == 0x00); i+= 0x10);
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// Go to first valid partition
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if ( i != 0x1FE) // Make sure it found a partition
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if (i != 0x1FE) // Make sure it found a partition
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{
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bootSector = globalBuffer[0x8 + i] + (globalBuffer[0x9 + i] << 8) + (globalBuffer[0xA + i] << 16) + ((globalBuffer[0xB + i] << 24) & 0x0F);
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} else {
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@ -347,55 +344,41 @@ bool FAT_InitFiles (bool initCard)
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CARD_ReadSector (bootSector, bootSec);
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// Store required information about the file system
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if (bootSec->sectorsPerFAT != 0)
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{
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discSecPerFAT = bootSec->sectorsPerFAT;
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}
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else
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{
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if (bootSec->bpb.sectorsPerFAT != 0) {
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discSecPerFAT = bootSec->bpb.sectorsPerFAT;
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} else {
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discSecPerFAT = bootSec->extBlock.fat32.sectorsPerFAT32;
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}
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if (bootSec->numSectorsSmall != 0)
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{
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discNumSec = bootSec->numSectorsSmall;
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}
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else
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{
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discNumSec = bootSec->numSectors;
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if (bootSec->bpb.numSectorsSmall != 0) {
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discNumSec = bootSec->bpb.numSectorsSmall;
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} else {
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discNumSec = bootSec->bpb.numSectors;
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}
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discBytePerSec = BYTES_PER_SECTOR; // Sector size is redefined to be 512 bytes
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discSecPerClus = bootSec->sectorsPerCluster * bootSec->bytesPerSector / BYTES_PER_SECTOR;
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discSecPerClus = bootSec->bpb.sectorsPerCluster * bootSec->bpb.bytesPerSector / BYTES_PER_SECTOR;
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discBytePerClus = discBytePerSec * discSecPerClus;
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discFAT = bootSector + bootSec->reservedSectors;
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discFAT = bootSector + bootSec->bpb.reservedSectors;
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discRootDir = discFAT + (bootSec->numFATs * discSecPerFAT);
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discData = discRootDir + ((bootSec->rootEntries * sizeof(DIR_ENT)) / BYTES_PER_SECTOR);
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discRootDir = discFAT + (bootSec->bpb.numFATs * discSecPerFAT);
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discData = discRootDir + ((bootSec->bpb.rootEntries * sizeof(DIR_ENT)) / BYTES_PER_SECTOR);
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if ((discNumSec - discData) / bootSec->sectorsPerCluster < 4085)
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{
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if ((discNumSec - discData) / bootSec->bpb.sectorsPerCluster < 4085) {
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discFileSystem = FS_FAT12;
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}
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else if ((discNumSec - discData) / bootSec->sectorsPerCluster < 65525)
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{
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} else if ((discNumSec - discData) / bootSec->bpb.sectorsPerCluster < 65525) {
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discFileSystem = FS_FAT16;
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}
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else
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{
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} else {
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discFileSystem = FS_FAT32;
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}
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if (discFileSystem != FS_FAT32)
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{
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if (discFileSystem != FS_FAT32) {
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discRootDirClus = FAT16_ROOT_DIR_CLUSTER;
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}
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else // Set up for the FAT32 way
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} else // Set up for the FAT32 way
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{
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discRootDirClus = bootSec->extBlock.fat32.rootClus;
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// Check if FAT mirroring is enabled
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if (!(bootSec->extBlock.fat32.extFlags & 0x80))
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{
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if (!(bootSec->extBlock.fat32.extFlags & 0x80)) {
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// Use the active FAT
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discFAT = discFAT + ( discSecPerFAT * (bootSec->extBlock.fat32.extFlags & 0x0F));
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}
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@ -425,8 +408,7 @@ u32 getBootFileCluster (const char* bootName)
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// Check if fat has been initialised
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if (discBytePerSec == 0)
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{
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if (discBytePerSec == 0) {
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return (CLUSTER_FREE);
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}
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@ -443,52 +425,42 @@ u32 getBootFileCluster (const char* bootName)
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wrkDirOffset = -1; // Start at entry zero, Compensating for increment
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while (!found && !notFound) {
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wrkDirOffset++;
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if (wrkDirOffset == BYTES_PER_SECTOR / sizeof (DIR_ENT))
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{
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if (wrkDirOffset == BYTES_PER_SECTOR / sizeof (DIR_ENT)) {
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wrkDirOffset = 0;
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wrkDirSector++;
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if ((wrkDirSector == discSecPerClus) && (wrkDirCluster != FAT16_ROOT_DIR_CLUSTER))
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{
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if ((wrkDirSector == discSecPerClus) && (wrkDirCluster != FAT16_ROOT_DIR_CLUSTER)) {
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wrkDirSector = 0;
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wrkDirCluster = FAT_NextCluster(wrkDirCluster);
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if (wrkDirCluster == CLUSTER_EOF)
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{
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if (wrkDirCluster == CLUSTER_EOF) {
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notFound = true;
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}
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firstSector = FAT_ClustToSect(wrkDirCluster);
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}
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else if ((wrkDirCluster == FAT16_ROOT_DIR_CLUSTER) && (wrkDirSector == (discData - discRootDir)))
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{
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} else if ((wrkDirCluster == FAT16_ROOT_DIR_CLUSTER) && (wrkDirSector == (discData - discRootDir))) {
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notFound = true; // Got to end of root dir
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}
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CARD_ReadSector (firstSector + wrkDirSector, globalBuffer);
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}
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dir = ((DIR_ENT*) globalBuffer)[wrkDirOffset];
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found = true;
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if ((dir.attrib & ATTRIB_DIR) || (dir.attrib & ATTRIB_VOL))
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{
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if ((dir.attrib & ATTRIB_DIR) || (dir.attrib & ATTRIB_VOL)) {
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found = false;
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}
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if(namelen<8 && dir.name[namelen]!=0x20) found = false;
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for (nameOffset = 0; nameOffset < namelen && found; nameOffset++)
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{
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if (namelen<8 && dir.name[namelen]!=0x20) found = false;
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for (nameOffset = 0; nameOffset < namelen && found; nameOffset++) {
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if (ucase(dir.name[nameOffset]) != bootName[nameOffset])
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found = false;
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}
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for (nameOffset = 0; nameOffset < 3 && found; nameOffset++)
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{
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for (nameOffset = 0; nameOffset < 3 && found; nameOffset++) {
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if (ucase(dir.ext[nameOffset]) != bootName[nameOffset+namelen+1])
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found = false;
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}
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if (dir.name[0] == FILE_LAST)
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{
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if (dir.name[0] == FILE_LAST) {
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notFound = true;
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}
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}
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// If no file is found, return CLUSTER_FREE
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if (notFound)
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{
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if (notFound) {
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return CLUSTER_FREE;
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}
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@ -513,8 +485,7 @@ u32 fileRead (char* buffer, u32 cluster, u32 startOffset, u32 length)
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}
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// Follow cluster list until desired one is found
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for (chunks = startOffset / discBytePerClus; chunks > 0; chunks--)
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{
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for (chunks = startOffset / discBytePerClus; chunks > 0; chunks--) {
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cluster = FAT_NextCluster (cluster);
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}
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@ -524,33 +495,30 @@ u32 fileRead (char* buffer, u32 cluster, u32 startOffset, u32 length)
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curByte = startOffset % BYTES_PER_SECTOR;
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// Load sector buffer for new position in file
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CARD_ReadSector( curSect + FAT_ClustToSect(cluster), globalBuffer);
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CARD_ReadSector(curSect + FAT_ClustToSect(cluster), globalBuffer);
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curSect++;
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// Number of bytes needed to read to align with a sector
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beginBytes = (BYTES_PER_SECTOR < length + curByte ? (BYTES_PER_SECTOR - curByte) : length);
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// Read first part from buffer, to align with sector boundary
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for (dataPos = 0 ; dataPos < beginBytes; dataPos++)
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{
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for (dataPos = 0 ; dataPos < beginBytes; dataPos++) {
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buffer[dataPos] = globalBuffer[curByte++];
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}
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// Read in all the 512 byte chunks of the file directly, saving time
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for ( chunks = ((int)length - beginBytes) / BYTES_PER_SECTOR; chunks > 0;)
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{
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for (chunks = ((int)length - beginBytes) / BYTES_PER_SECTOR; chunks > 0;) {
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int sectorsToRead;
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// Move to the next cluster if necessary
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if (curSect >= discSecPerClus)
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{
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if (curSect >= discSecPerClus) {
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curSect = 0;
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cluster = FAT_NextCluster (cluster);
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}
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// Calculate how many sectors to read (read a maximum of discSecPerClus at a time)
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sectorsToRead = discSecPerClus - curSect;
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if(chunks < sectorsToRead)
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if (chunks < sectorsToRead)
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sectorsToRead = chunks;
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// Read the sectors
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@ -561,21 +529,18 @@ u32 fileRead (char* buffer, u32 cluster, u32 startOffset, u32 length)
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}
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// Take care of any bytes left over before end of read
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if (dataPos < length)
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{
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if (dataPos < length) {
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// Update the read buffer
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curByte = 0;
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if (curSect >= discSecPerClus)
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{
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if (curSect >= discSecPerClus) {
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curSect = 0;
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cluster = FAT_NextCluster (cluster);
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}
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CARD_ReadSector( curSect + FAT_ClustToSect( cluster), globalBuffer);
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CARD_ReadSector(curSect + FAT_ClustToSect(cluster), globalBuffer);
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// Read in last partial chunk
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for (; dataPos < length; dataPos++)
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{
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for (; dataPos < length; dataPos++) {
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buffer[dataPos] = globalBuffer[curByte];
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curByte++;
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}
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