litex/software/libextra/fatfs.c

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/*
* Milkymist SoC (Software)
* Copyright (C) 2007, 2008, 2009, 2010 Sebastien Bourdeauducq
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, version 3 of the License.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <ctype.h>
#include <endian.h>
#include <console.h>
#include <blockdev.h>
#include <fatfs.h>
//#define DEBUG
#define BLOCK_SIZE 512
struct partition_descriptor {
unsigned char flags;
unsigned char start_head;
unsigned short start_cylinder;
unsigned char type;
unsigned char end_head;
unsigned short end_cylinder;
unsigned int start_sector;
unsigned int end_sector;
} __attribute__((packed));
struct firstsector {
unsigned char bootsector[446];
struct partition_descriptor partitions[4];
unsigned char signature[2];
} __attribute__((packed));
struct fat16_firstsector {
/* Common to FATxx */
char jmp[3];
char oem[8];
unsigned short bytes_per_sector;
unsigned char sectors_per_cluster;
unsigned short reserved_sectors;
unsigned char number_of_fat;
unsigned short max_root_entries;
unsigned short total_sectors_short;
unsigned char media_descriptor;
unsigned short sectors_per_fat;
unsigned short sectors_per_track;
unsigned short head_count;
unsigned int hidden_sectors;
unsigned int total_sectors;
/* FAT16 specific */
unsigned char drive_nr;
unsigned char reserved;
unsigned char ext_boot_signature;
unsigned int id;
unsigned char volume_label[11];
unsigned char fstype[8];
unsigned char bootcode[448];
unsigned char signature[2];
} __attribute__((packed));
struct directory_entry {
unsigned char filename[8];
unsigned char extension[3];
unsigned char attributes;
unsigned char reserved;
unsigned char create_time_ms;
unsigned short create_time;
unsigned short create_date;
unsigned short last_access;
unsigned short ea_index;
unsigned short lastm_time;
unsigned short lastm_date;
unsigned short first_cluster;
unsigned int file_size;
} __attribute__((packed));
struct directory_entry_lfn {
unsigned char seq;
unsigned short name1[5]; /* UTF16 */
unsigned char attributes;
unsigned char reserved;
unsigned char checksum;
unsigned short name2[6];
unsigned short first_cluster;
unsigned short name3[2];
} __attribute__((packed));
#define PARTITION_TYPE_FAT16 0x06
#define PARTITION_TYPE_FAT32 0x0b
static int fatfs_partition_start_sector; /* Sector# of the beginning of the FAT16 partition */
static int fatfs_sectors_per_cluster;
static int fatfs_fat_sector; /* Sector of the first FAT */
static int fatfs_fat_entries; /* Number of entries in the FAT */
static int fatfs_max_root_entries;
static int fatfs_root_table_sector; /* Sector# of the beginning of the root table */
static int fatfs_fat_cached_sector;
static unsigned short int fatfs_fat_sector_cache[BLOCK_SIZE/2];
static int fatfs_dir_cached_sector;
static struct directory_entry fatfs_dir_sector_cache[BLOCK_SIZE/sizeof(struct directory_entry)];
static int fatfs_data_start_sector;
int fatfs_init(int devnr)
{
struct firstsector s0;
struct fat16_firstsector s;
int i;
if(!bd_init(devnr)) {
printf("E: Unable to initialize memory card driver\n");
return 0;
}
if(bd_has_part_table(devnr)) {
/* Read sector 0, with partition table */
if(!bd_readblock(0, (void *)&s0)) {
printf("E: Unable to read block 0\n");
return 0;
}
fatfs_partition_start_sector = -1;
for(i=0;i<4;i++)
if((s0.partitions[i].type == PARTITION_TYPE_FAT16)
||(s0.partitions[i].type == PARTITION_TYPE_FAT32)) {
#ifdef DEBUG
printf("I: Using partition #%d: start sector %08x, end sector %08x\n", i,
le32toh(s0.partitions[i].start_sector), le32toh(s0.partitions[i].end_sector));
#endif
fatfs_partition_start_sector = le32toh(s0.partitions[i].start_sector);
break;
}
if(fatfs_partition_start_sector == -1) {
printf("E: No FAT partition was found\n");
return 0;
}
} else
fatfs_partition_start_sector = 0;
/* Read first FAT16 sector */
if(!bd_readblock(fatfs_partition_start_sector, (void *)&s)) {
printf("E: Unable to read first FAT sector\n");
return 0;
}
#ifdef DEBUG
{
char oem[9];
char volume_label[12];
memcpy(oem, s.oem, 8);
oem[8] = 0;
memcpy(volume_label, s.volume_label, 11);
volume_label[11] = 0;
printf("I: OEM name: %s\n", oem);
printf("I: Volume label: %s\n", volume_label);
}
#endif
if(le16toh(s.bytes_per_sector) != BLOCK_SIZE) {
printf("E: Unexpected number of bytes per sector (%d)\n", le16toh(s.bytes_per_sector));
return 0;
}
fatfs_sectors_per_cluster = s.sectors_per_cluster;
fatfs_fat_entries = (le16toh(s.sectors_per_fat)*BLOCK_SIZE)/2;
fatfs_fat_sector = fatfs_partition_start_sector + 1;
fatfs_fat_cached_sector = -1;
fatfs_max_root_entries = le16toh(s.max_root_entries);
fatfs_root_table_sector = fatfs_fat_sector + s.number_of_fat*le16toh(s.sectors_per_fat);
fatfs_dir_cached_sector = -1;
fatfs_data_start_sector = fatfs_root_table_sector + (fatfs_max_root_entries*sizeof(struct directory_entry))/BLOCK_SIZE;
if(fatfs_max_root_entries == 0) {
printf("E: Your memory card uses FAT32, which is not supported.\n");
printf("E: Please reformat your card using FAT16, e.g. use mkdosfs -F 16\n");
printf("E: FAT32 support would be an appreciated contribution.\n");
return 0;
}
#ifdef DEBUG
printf("I: Cluster is %d sectors, FAT has %d entries, FAT 1 is at sector %d,\nI: root table is at sector %d (max %d), data is at sector %d, nb of fat: %d\n",
fatfs_sectors_per_cluster, fatfs_fat_entries, fatfs_fat_sector,
fatfs_root_table_sector, fatfs_max_root_entries,
fatfs_data_start_sector, s.number_of_fat);
#endif
return 1;
}
static int fatfs_read_fat(int offset)
{
int wanted_sector;
if((offset < 0) || (offset >= fatfs_fat_entries)) {
printf("E: Incorrect offset %d in fatfs_read_fat\n", offset);
return -1;
}
wanted_sector = fatfs_fat_sector + (offset*2)/BLOCK_SIZE;
if(wanted_sector != fatfs_fat_cached_sector) {
if(!bd_readblock(wanted_sector, (void *)&fatfs_fat_sector_cache)) {
printf("E: Memory card failed (FAT), sector %d\n", wanted_sector);
return -1;
}
fatfs_fat_cached_sector = wanted_sector;
}
return le16toh(fatfs_fat_sector_cache[offset % (BLOCK_SIZE/2)]);
}
static const struct directory_entry *fatfs_read_root_directory(int offset)
{
int wanted_sector;
if((offset < 0) || (offset >= fatfs_max_root_entries))
return NULL;
wanted_sector = fatfs_root_table_sector + (offset*sizeof(struct directory_entry))/BLOCK_SIZE;
if(wanted_sector != fatfs_dir_cached_sector) {
if(!bd_readblock(wanted_sector, (void *)&fatfs_dir_sector_cache)) {
printf("E: Memory card failed (Rootdir), sector %d\n", wanted_sector);
return NULL;
}
fatfs_dir_cached_sector = wanted_sector;
}
return &fatfs_dir_sector_cache[offset % (BLOCK_SIZE/sizeof(struct directory_entry))];
}
static void lfn_to_ascii(const struct directory_entry_lfn *entry, char *name, int terminate)
{
int i;
unsigned short c;
for(i=0;i<5;i++) {
c = le16toh(entry->name1[i]);
if(c <= 255) {
*name = c;
name++;
if(c == 0) return;
}
}
for(i=0;i<6;i++) {
c = le16toh(entry->name2[i]);
if(c <= 255) {
*name = c;
name++;
if(c == 0) return;
}
}
for(i=0;i<2;i++) {
c = le16toh(entry->name3[i]);
if(c <= 255) {
*name = c;
name++;
if(c == 0) return;
}
}
if(terminate)
*name = 0;
}
static int fatfs_is_regular(const struct directory_entry *entry)
{
return ((entry->attributes & 0x10) == 0)
&& ((entry->attributes & 0x08) == 0)
&& (entry->filename[0] != 0xe5);
}
int fatfs_list_files(fatfs_dir_callback cb, void *param)
{
const struct directory_entry *entry;
char fmtbuf[8+1+3+1];
char longname[131];
int has_longname;
int i, j, k;
has_longname = 0;
longname[sizeof(longname)-1] = 0; /* avoid crashing when reading a corrupt FS */
for(k=0;k<fatfs_max_root_entries;k++) {
entry = fatfs_read_root_directory(k);
#ifdef DEBUG
printf("I: Read entry with attribute %02x\n", entry->attributes);
#endif
if(entry->attributes == 0x0f) {
const struct directory_entry_lfn *entry_lfn;
unsigned char frag;
int terminate;
entry_lfn = (const struct directory_entry_lfn *)entry;
frag = entry_lfn->seq & 0x3f;
terminate = entry_lfn->seq & 0x40;
if(frag*13 < sizeof(longname)) {
lfn_to_ascii((const struct directory_entry_lfn *)entry, &longname[(frag-1)*13], terminate);
if(frag == 1) has_longname = 1;
}
continue;
} else {
if(!fatfs_is_regular(entry)) {
has_longname = 0;
continue;
}
}
if(entry == NULL) return 0;
if(entry->filename[0] == 0) {
has_longname = 0;
break;
}
j = 0;
for(i=0;i<8;i++) {
if(entry->filename[i] == ' ') break;
fmtbuf[j++] = entry->filename[i];
}
fmtbuf[j++] = '.';
for(i=0;i<3;i++) {
if(entry->extension[i] == ' ') break;
fmtbuf[j++] = entry->extension[i];
}
fmtbuf[j++] = 0;
if(!cb(fmtbuf, has_longname ? longname : fmtbuf, param)) return 0;
has_longname = 0;
}
return 1;
}
static const struct directory_entry *fatfs_find_file_by_name(const char *filename)
{
char searched_filename[8];
char searched_extension[3];
char *dot;
const char *c;
int i;
const struct directory_entry *entry;
dot = strrchr(filename, '.');
if(dot == NULL)
return NULL;
memset(searched_filename, ' ', 8);
memset(searched_extension, ' ', 3);
i = 0;
for(c=filename;c<dot;c++)
searched_filename[i++] = toupper(*c);
i = 0;
for(c=dot+1;*c!=0;c++)
searched_extension[i++] = toupper(*c);
for(i=0;i<fatfs_max_root_entries;i++) {
entry = fatfs_read_root_directory(i);
if(entry == NULL) break;
if(entry->filename[0] == 0) break;
if(!fatfs_is_regular(entry)) continue;
if(!memcmp(searched_filename, entry->filename, 8)
&&!memcmp(searched_extension, entry->extension, 3))
return entry;
}
return NULL;
}
static int fatfs_load_cluster(int clustern, char *buffer, int maxsectors)
{
int startsector;
int i;
int toread;
clustern = clustern - 2;
startsector = fatfs_data_start_sector + clustern*fatfs_sectors_per_cluster;
if(maxsectors < fatfs_sectors_per_cluster)
toread = maxsectors;
else
toread = fatfs_sectors_per_cluster;
for(i=0;i<toread;i++)
if(!bd_readblock(startsector+i, (unsigned char *)buffer+i*BLOCK_SIZE)) {
printf("E: Memory card failed (Cluster), sector %d\n", startsector+i);
return 0;
}
return 1;
}
int fatfs_load(const char *filename, char *buffer, int size, int *realsize)
{
const struct directory_entry *entry;
int cluster_size;
int cluster;
int n;
cluster_size = fatfs_sectors_per_cluster*BLOCK_SIZE;
size /= BLOCK_SIZE;
entry = fatfs_find_file_by_name(filename);
if(entry == NULL) {
printf("E: File not found: %s\n", filename);
return 0;
}
if(realsize != NULL) *realsize = le32toh(entry->file_size);
n = 0;
cluster = le16toh(entry->first_cluster);
while(size > 0) {
if(!fatfs_load_cluster(cluster, buffer+n*cluster_size, size))
return 0;
size -= fatfs_sectors_per_cluster;
n++;
cluster = fatfs_read_fat(cluster);
if(cluster >= 0xFFF8) break;
if(cluster == -1) return 0;
}
//putsnonl("\n");
return n*cluster_size;
}
void fatfs_done(void)
{
bd_done();
}