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sdfat.c
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sdfat.c
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/*
Minimalist SD FAT filesystem IO by NOP90
Uses 3DS SDIO Handling code from Kane49 adaption of the sdmmc module made for libnds
based on information from
- http://www.pjrc.com/tech/8051/ide/fat32.html
limitations:
- only 8.3 file name support
- only 1 file opened at a time
- no file or directory creation
- no file resizing, can write only on already allocated sectors
*/
#include <stdint.h>
#include "sdfat.h"
#include "sdmmc.h"
#include "minlib.h"
static uint8_t sect[SECTSIZE],filesect[SECTSIZE], fatsect[SECTSIZE];
static FATVolume fat;
static uint32_t rootdirsect, curdirsect, curfilesect, curfatsect;
static FATDirEntry curdirentry, curdir, curfile;
static uint8_t direntrycount,curdirsectorcluster;
static uint32_t curfilesectorcluster,filesectorcount;
static uint32_t lba_addr(uint32_t cluster_number){return cluster_begin_lba() + 32 * (fat.BPB_RootDirEnt / fat.BPB_BytsPerSec) + (cluster_number - 2) * fat.BPB_SecPerClus;}
static uint32_t cluster_begin_lba() {return fat.LBA_Begin + fat.BPB_RsvdSecCnt + (fat.BPB_NumFATs * fat.BPB_FATS);}
static uint32_t fat_begin_lba() {return fat.LBA_Begin + fat.BPB_RsvdSecCnt;}
int mount(){
uint8_t i;
uint32_t temp;
int8_t partition;
sdmmc_controller_init();
temp = sdmmc_sdcard_init() ;
if (sdmmc_sdcard_readsectors(0,1,(void*)§)) return FAT_ERR_SDREAD; // Error reading MBR
else {
temp=sect[510] + (sect[511]<<8);
if(temp!=0xAA55) return FAT_ERR_MBR; // Check failed
else {
partition=-1;
for(i=0;i<4;i++) { // Max four partition to check
switch (sect[450+i*16]) { // Partition type
case 0x06: // FAT 16 CHS
temp=sect[447+i*16]*63+sect[448+i*16]-1;
if ((partition==-1) && temp) {
partition=i;
fat.LBA_Begin=temp;
fat.FAT_RecordLen=16;
}
break;
case 0x0B: // FAT 32 CHS
temp=sect[447+i*16]*63+sect[448+i*16]-1;
if ((partition==-1) && temp) {
partition=i;
fat.LBA_Begin=temp;
fat.FAT_RecordLen=32;
}
break;
case 0x0C: //FAT 32 LBA
temp=sect[454+i*16]+(sect[455+i*16]<<8)+(sect[456+i*16]<<16)+(sect[457+i*16]<<24);
if ((partition==-1) && temp) {
partition=i;
fat.LBA_Begin=temp;
fat.FAT_RecordLen=32;
}
break;
case 0x0E: // FAT 16 LBA
temp=sect[454+i*16]+(sect[455+i*16]<<8)+(sect[456+i*16]<<16)+(sect[457+i*16]<<24);
if ((partition==-1) && temp) {
partition=i;
fat.LBA_Begin=temp;
fat.FAT_RecordLen=16;
}
break;
default:
break;
}
if (partition==-1) return FAT_ERR_PARTITION; // No valid partition found
else {
if (sdmmc_sdcard_readsectors(fat.LBA_Begin,1,(void*)§)) return FAT_ERR_SDREAD; // Error reading FAT ID
else {
temp=sect[510]+(sect[511]<<8);
if(temp!=0xAA55) return FAT_ERR_FATID; // Check failed
else {
fat.BPB_BytsPerSec=sect[11]+(sect[12]<<8);
fat.BPB_SecPerClus=sect[13];
fat.BPB_RsvdSecCnt=sect[14]+(sect[15]<<8);
fat.BPB_NumFATs=sect[16];
fat.BPB_RootDirEnt=sect[17] + (sect[18]<<8);
if (fat.FAT_RecordLen==16){
fat.BPB_RootDirEnt=sect[17] + (sect[18]<<8);
fat.BPB_FATS=sect[22]+(sect[23]<<8);
fat.BPB_RootClus=2;
} else {
fat.BPB_RootDirEnt=0;
fat.BPB_FATS=sect[36]+(sect[37]<<8)+(sect[38]<<16)+(sect[39]<<24);
fat.BPB_RootClus=sect[44]+(sect[45]<<8)+(sect[46]<<16)+(sect[47]<<24);
}
curfatsect=fat_begin_lba(fat);
if (sdmmc_sdcard_readsectors(curfatsect,1,(void*)&fatsect)) return -1;
rootdirsect = lba_addr(fat.BPB_RootClus);
return changedir("\\");
}
}
}
}
}
}
}
int movefirstdirentry(){
if ((curdirsect!=lba_addr(curdir.DIR_FstClus))|(curdirsectorcluster!=0)){
if (sdmmc_sdcard_readsectors(lba_addr(curdir.DIR_FstClus),1,(void*)§)) return -1;
curdirsect=lba_addr(curdir.DIR_FstClus);
curdirsectorcluster=0;
}
direntrycount=0;
return movenextdirentry();
}
int movenextdirentry(){
uint8_t j;
if (sect[32*(direntrycount)]==0) return -1;
if(++direntrycount==17){
if(movedirnextsect()) return -1;
return movenextdirentry();
} else {
if ((sect[32*(direntrycount-1)]==0xE5)||(sect[32*(direntrycount-1) + 11] & 14)) return movenextdirentry();
else {
for(j=0;j<11;j++) curdirentry.DIR_Name[j]=sect[32*(direntrycount-1) + j];
curdirentry.DIR_Attr = (sect[32*(direntrycount-1) + 11] & 16);
curdirentry.DIR_FstClus = (sect[32*(direntrycount-1) + 20]<<16) + (sect[32*(direntrycount-1) + 21]<<24) + sect[32*(direntrycount-1) + 26] + (sect[32*(direntrycount-1) + 27]<<8);
curdirentry.DIR_FileSize = sect[32*(direntrycount-1) + 28] + (sect[32*(direntrycount-1) + 29]<<8) + (sect[32*(direntrycount-1) + 30]<<16) + (sect[32*(direntrycount-1) + 31]<<24);
return 0;
}
}
}
int changedir(char* buf){ // Change current directory
uint8_t i;
if ((buf[0]==0)) return -1;
if ((buf[0]=='\\')&&(buf[1]==0)){
if (sdmmc_sdcard_readsectors(lba_addr(fat.BPB_RootClus),1,(void*)§)) return FAT_ERR_SDREAD;
curdirsect = lba_addr(fat.BPB_RootClus);
curdirsectorcluster=0;
curdir.DIR_Name[0]='\\';
curdir.DIR_Name[1]=0x20;
curdir.DIR_Name[2]=0x20;
curdir.DIR_Name[3]=0x20;
curdir.DIR_Name[4]=0x20;
curdir.DIR_Name[5]=0x20;
curdir.DIR_Name[6]=0x20;
curdir.DIR_Name[7]=0x20;
curdir.DIR_Name[8]=0x20;
curdir.DIR_Name[9]=0x20;
curdir.DIR_Name[10]=0x20;
curdir.DIR_Attr = 17;
curdir.DIR_FstClus = fat.BPB_RootClus;
curdir.DIR_FileSize = 0;
direntrycount=0;
return 0;
}
if ((buf[0]=='.')&&(buf[1]==0)) return (direntrycount=0);
// note: ".." can be searched like any other dir
if (movefirstdirentry()) return -1;
while(cmpname(buf,curdirentry.DIR_Name)) if (movenextdirentry()) return -2;
if (curdirentry.DIR_Attr & ATT_DIRECTORY) {
if (sdmmc_sdcard_readsectors(lba_addr(curdirentry.DIR_FstClus),1,(void*)§)) return FAT_ERR_SDREAD;
curdirsect = lba_addr(curdirentry.DIR_FstClus);
curdirsectorcluster=0;
for (i=0; i<11;i++) curdir.DIR_Name[i]=curdirentry.DIR_Name[i];
curdir.DIR_Attr = curdirentry.DIR_Attr;
curdir.DIR_FstClus = curdirentry.DIR_FstClus;
curdir.DIR_FileSize = curdirentry.DIR_FileSize;;
return (direntrycount=0);
}
return -1;
}
int openf(char* buf){ // Load first cluster of a file in buffer
if (movefirstdirentry()) return -1;
while(cmpname(buf,curdirentry.DIR_Name)) if (movenextdirentry()) return -2;
if (!(curdirentry.DIR_Attr & ATT_DIRECTORY)) {
if (sdmmc_sdcard_readsectors(lba_addr(curdirentry.DIR_FstClus),1,(void*)&filesect)) return FAT_ERR_SDREAD;
curfilesect = lba_addr(curdirentry.DIR_FstClus);
curfile.DIR_Attr = curdirentry.DIR_Attr;
curfile.DIR_FstClus = curdirentry.DIR_FstClus;
curfile.DIR_FileSize = curdirentry.DIR_FileSize;;
return (filesectorcount=curfilesectorcluster=0);
}
return -1;
}
uint8_t getcharf(uint32_t pos){
return filesect[pos % SECTSIZE];
}
void setcharf(uint32_t pos, uint8_t val){
filesect[pos % SECTSIZE] = val;
}
uint32_t posoffile(){ //only for debug
return (filesectorcount * SECTSIZE);
}
uint8_t endoffile(){
return ((filesectorcount * SECTSIZE)>= curfile.DIR_FileSize);
}
int readf(){ // Read the next cluster of a file
uint32_t nextsect;
if (endoffile()) return -1;
filesectorcount++;
if (++curfilesectorcluster == fat.BPB_SecPerClus){
if ((nextsect = getnextsect(curfilesect))==0) return -1;
curfilesect=nextsect;
curfilesectorcluster=0;
}
if (sdmmc_sdcard_readsectors(curfilesect+curfilesectorcluster,1,(void*)&filesect)) return -1;
else return 0;
}
int writef(){ // Flush changes on current buffer to the file (can modify only positions allocated on disk)
return sdmmc_sdcard_writesector(curfilesect + curfilesectorcluster, (void*)& filesect);
}
static int movedirnextsect(){
uint32_t nextsect;
if (++curdirsectorcluster == fat.BPB_SecPerClus){
nextsect = getnextsect(curdirsect);
if (nextsect==0) return -1;
curdirsect=nextsect;
curdirsectorcluster=0;
}
if (sdmmc_sdcard_readsectors(curdirsect+curdirsectorcluster,1,(void*)§)) return -1;
else return (direntrycount=0);
}
static uint32_t getnextsect(uint32_t sect){ // not tested yet
uint32_t cluster, fatnumsect, fatentry;
cluster = (sect - cluster_begin_lba()- 32 * (fat.BPB_RootDirEnt / fat.BPB_BytsPerSec)) / fat.BPB_SecPerClus + 2;
if (fat.FAT_RecordLen==32){
fatnumsect= lba_addr(cluster>>7);
fatentry = cluster|127;
} else {
fatnumsect= lba_addr(cluster>>8);
fatentry = cluster|255;
}
if (curfatsect!=fatnumsect){
if (sdmmc_sdcard_readsectors(fatnumsect,1,(void*)&fatsect)) return -1;
curfatsect=fatnumsect;
}
if (fat.FAT_RecordLen==32) return fatsect[fatentry*4] + (fatsect[fatentry*4 +1]<<8) + (fatsect[fatentry*4 +2]<<16) + (fatsect[fatentry*4 +3]<<24);
else return fatsect[fatentry*2] + (fatsect[fatentry*2 +1]<<8) ;
}
static int cmpname(char* name1, char* name2){
uint8_t i;
for (i=0; (i<11) & !(((name1[i]==0x20)|(name1[i]==0))&(name2[i]==0x20)); i++) if (name1[i]!=name2[i]) return -1;
return 0;
}
void getdirentryname(char* buf){
uint8_t i;
for (i=0; i<11;i++) buf[i]=curdirentry.DIR_Name[i];
}
uint8_t getdirentryattr(){
return curdirentry.DIR_Attr;
}
uint32_t getfilesize() {return curfile.DIR_FileSize;}
uint32_t getsect() {return curdirsect+curdirsectorcluster;}
void entryname2str(char* buf,char* entryname){
int j,i;
for(i=j=0;j<8;j++) if (entryname[j]!=0x20) buf[i++]=entryname[j];
if (entryname[8]==0x20) buf[i++]=0;
else {
buf[i++]=0x2E;
for(j=8;j<11;j++) if (entryname[j]!=0x20) buf[i++]=entryname[j];
buf[i]=0;
}
}