Matthew Shoemaker
USB Host Lite downloaded from NXP web site. Untested! Compiled, dropped on MBED, booted up, and get the console message that it is initializing the stack. I however do not have the ability to connect a USB Memory device to test it.
Fat/usbhost_fat.c
- Committer:
- mshoemaker
- Date:
- 2010-01-13
- Revision:
- 0:0826fcc5d020
File content as of revision 0:0826fcc5d020:
/*
**************************************************************************************************************
* NXP USB Host Stack
*
* (c) Copyright 2008, NXP SemiConductors
* (c) Copyright 2008, OnChip Technologies LLC
* All Rights Reserved
*
* www.nxp.com
* www.onchiptech.com
*
* File : usbhost_fat.c
* Programmer(s) : Ravikanth.P
* Version :
*
**************************************************************************************************************
*/
/*
**************************************************************************************************************
* INCLUDE HEADER FILES
**************************************************************************************************************
*/
#include "usbhost_fat.h"
/*
**************************************************************************************************************
* GLOBAL VARIABLES
**************************************************************************************************************
*/
#define MAX_FILE_DESCRIPTORS 2
static BOOT_SEC FAT_BootSec;
static FILE_ENTRY FAT_FileEntry[MAX_FILE_DESCRIPTORS];
/*
**************************************************************************************************************
* INITIALIZE THE FILE SYSTEM
*
* Description: This function initializes the FAT16 file system
*
* Arguments : None
*
* Returns : OK if Success
* ERR_INVALID_BOOTSIG if Failed
*
**************************************************************************************************************
*/
USB_INT32S FAT_Init (void)
{
USB_INT16U boot_sig;
USB_INT32S rc, i;
FILE_ENTRY *entry;
for (i=0;i<MAX_FILE_DESCRIPTORS;i++) {
entry = &FAT_FileEntry[i];
entry->CurrClus = 0;
entry->CurrClusOffset = 0;
entry->FileSize = 0;
entry->EntrySec = 0;
entry->EntrySecOffset = 0;
entry->FileStatus = 0;
}
MS_BulkRecv(0, 1, FATBuffer);
boot_sig = ReadLE16U(&FATBuffer[510]);
if (boot_sig != 0xAA55) {
rc = ERR_INVALID_BOOT_SIG;
} else {
if (FATBuffer[0] != 0xEB && FATBuffer[0] != 0xE9) {
FAT_BootSec.BootSecOffset = ReadLE32U(&FATBuffer[454]);
MS_BulkRecv(FAT_BootSec.BootSecOffset, 1, FATBuffer);
}
FAT_BootSec.BytsPerSec = ReadLE16U(&FATBuffer[11]); /* Bytes per cluster */
FAT_BootSec.SecPerClus = FATBuffer[13]; /* Sectors per cluster */
/* Reserved sector count */
FAT_BootSec.RsvdSecCnt = ReadLE16U(&FATBuffer[14]) + FAT_BootSec.BootSecOffset;
FAT_BootSec.NumFATs = FATBuffer[16]; /* Number of FAT copies */
FAT_BootSec.RootEntCnt = ReadLE16U(&FATBuffer[17]); /* Root entry count */
FAT_BootSec.TotSec16 = ReadLE16U(&FATBuffer[19]); /* Total FAT16 sectors */
FAT_BootSec.TotSec32 = ReadLE32U(&FATBuffer[32]); /* Total FAT32 sectors */
FAT_BootSec.FATSz16 = ReadLE16U(&FATBuffer[22]); /* Size of the FAT table */
/* Bytes per cluster */
FAT_BootSec.BytsPerClus = (FAT_BootSec.BytsPerSec * FAT_BootSec.SecPerClus);
/* Root directory starting sector */
FAT_BootSec.RootDirStartSec = FAT_BootSec.RsvdSecCnt + (FAT_BootSec.FATSz16 * FAT_BootSec.NumFATs);
/* Sectors occupied by root directory */
FAT_BootSec.RootDirSec = ((FAT_BootSec.RootEntCnt * 32) + (FAT_BootSec.BytsPerSec - 1)) /
(FAT_BootSec.BytsPerSec);
/* First data sector */
FAT_BootSec.FirstDataSec = FAT_BootSec.RootDirStartSec + FAT_BootSec.RootDirSec;
FAT_BootSec.FATType = FAT_GetFATType(); /* Type of FAT */
if (FAT_BootSec.FATType == FAT_16) {
rc = OK;
} else {
rc = ERR_FAT_NOT_SUPPORTED;
PRINT_Err(rc);
}
}
return (rc);
}
/*
**************************************************************************************************************
* GET FILE SYSTEM TYPE
*
* Description: This function returns the file system type with which the disk is formatted
*
* Arguments : None
*
* Returns : FAT16 On Success
* ERR_FAT_TYPE On Failure
*
**************************************************************************************************************
*/
USB_INT08U FAT_GetFATType (void)
{
USB_INT08U fat_type;
USB_INT32U tot_sec;
USB_INT32U tot_data_clus;
if (FAT_BootSec.TotSec16 != 0) { /* Get total sectors in the disk */
tot_sec = FAT_BootSec.TotSec16;
} else {
tot_sec = FAT_BootSec.TotSec32;
}
tot_data_clus = tot_sec / (FAT_BootSec.SecPerClus); /* Get total data clusters in the disk */
/* If total data clusters >= 4085 and */
/* < 65525, then it is FAT16 file system */
if (tot_data_clus >= 4085 && tot_data_clus < 65525) {
fat_type = FAT_16;
} else {
fat_type = 0;
}
return (fat_type);
}
/*
**************************************************************************************************************
* OPENING A FILE
*
* Description: This function stores the attributes of a file, such as starting cluster, file size,
* sector where the file entry is stored and offset of the entry in that sector
*
* Arguments : file_name Name of the file. The file must be in root directory.
*
* Returns : pointer to the entry On Success
* NULL On Failure
*
* Modifed 6/9/08 WCB returns a file descriptor which is the INDEX+1 to the entry.
* returning the entry address itself could be interpreted as a negative number --
* and thus an error -- for memory locations of 0x80000000 and above. We return
* INDEX+1 instead of just the index to avoid returning a file descriptor of zero,
* which could be potentially confused with an error.
*
**************************************************************************************************************
*/
USB_INT32S FILE_Open (USB_INT08U *file_name,
USB_INT08U flags)
{
USB_INT32S rc;
FILE_ENTRY *entry = 0;
USB_INT32S fd = -1;
do {
if (FAT_FileEntry[++fd].FileStatus == 0)
entry = &FAT_FileEntry[fd];
} while ((entry == 0) && (fd < MAX_FILE_DESCRIPTORS-1));
if (entry == 0) {
return (ERR_OPEN_LIMIT_REACHED);
}
if (flags == RDONLY) { /* Search for a file. If it doesn't exist, don't create it */
rc = FAT_FindEntry(file_name, entry);
if (rc == MATCH_FOUND) {
entry->FileStatus = 1;
rc = fd+1;
}
} else { /* Search for a file. If it doesn't exist, create it */
rc = FAT_CreateEntry(file_name, entry);
if (rc == MATCH_FOUND) {
entry->FileStatus = 1;
rc = fd+1;
}
}
return (rc);
}
/*
**************************************************************************************************************
* FINDING AN ENTRY
*
* Description: This function searches for a file name in the root directory
*
* Arguments : ent_name_given Pointer to the file name to be searched.
* entry Pointer to the entry structure. The attributes of the file are stored in this
* structure if the file was found in the root directory.
*
* Returns : MATCH_FOUND if the file was found in the root directory.
* MATCH_NOT_FOUND if the file was not found in the root directory.
*
**************************************************************************************************************
*/
USB_INT32S FAT_FindEntry (USB_INT08U *ent_name_given,
FILE_ENTRY *entry)
{
USB_INT32U sec_num;
volatile USB_INT08U *buf;
USB_INT08U ent_type;
USB_INT08U ent_name_read[13];
for (sec_num = FAT_BootSec.RootDirStartSec; /* For all the sectors in root directory */
sec_num < (FAT_BootSec.RootDirStartSec + FAT_BootSec.RootDirSec);
sec_num++) {
MS_BulkRecv(sec_num, 1, FATBuffer); /* Read one sector */
buf = FATBuffer;
while (buf < (FATBuffer + FAT_BootSec.BytsPerSec)) {
ent_type = FAT_ChkEntType(buf); /* Check for the entry type */
if (ent_type == SFN_ENTRY) { /* If it is short entry get short file name */
FAT_GetSFN(buf, ent_name_read);
/* Compare given name with this name case insensitively */
if (FAT_StrCaseCmp(ent_name_given, ent_name_read) == MATCH_FOUND) {
entry->CurrClus = ReadLE16U(&buf[26]); /* If they are same, get starting cluster */
entry->FileSize = ReadLE32U(&buf[28]); /* Get file size */
entry->EntrySec = sec_num; /* Get sector number where the filename is located */
/* Get offset in this sector where the filename is located */
entry->EntrySecOffset = buf - FATBuffer;
return (MATCH_FOUND);
}
}
if (ent_type == LAST_ENTRY) { /* If it is the last entry, no more entries will exist. Return */
return (MATCH_NOT_FOUND);
}
buf = buf + 32; /* Move to the next entry */
}
}
return (MATCH_NOT_FOUND);
}
/*
**************************************************************************************************************
* GET SHORT FILE NAME AND EXTENSION OF A FILE
*
* Description: This function reads the short file name and extension corresponding to a file
*
* Arguments : ent_buf buffer which contains the 32 byte entry of a file
* name buffer to store the file name and extension of a file
*
* Returns : None
*
**************************************************************************************************************
*/
void FAT_GetSFN (volatile USB_INT08U *entry,
USB_INT08U *name)
{
USB_INT08U ext[4]; /* Buffer to store the extension of a file */
USB_INT08U *ext_ptr;
ext_ptr = ext;
FAT_GetSfnName(entry, name); /* Get file name into "name" buffer */
FAT_GetSfnExt(entry, ext_ptr); /* Get extension into "ext" buffer */
while (*name) { /* Goto the end of the filename */
name++;
}
if (*ext_ptr) { /* If the extension exists, put a '.' charecter */
*name = '.';
name++;
}
while (*ext_ptr) { /* Append the extension to the file name */
*name = *ext_ptr;
name++;
ext_ptr++;
}
*name = '\0';
}
/*
**************************************************************************************************************
* GET SHORT FILE NAME OF A FILE
*
* Description: This function reads the short file name of a file
*
* Arguments : ent_buf buffer which contains the 32 byte entry of a file
* name buffer to store the short file name of a file
*
* Returns : None
*
**************************************************************************************************************
*/
void FAT_GetSfnName (volatile USB_INT08U *entry,
USB_INT08U *name)
{
USB_INT32U cnt;
cnt = 0;
while (cnt < 8) {
*name = *entry; /* Get first 8 charecters of an SFN entry */
name++;
entry++;
cnt++;
}
*name = 0;
name--;
while (*name == 0x20) { /* If any spaces exist after the file name, replace them with 0 */
*name = 0;
name--;
}
}
/*
**************************************************************************************************************
* GET EXTENSION OF A FILE
*
* Description: This function reads the extension of a file
*
* Arguments : ent_buf buffer which contains the 32 byte entry of a file
* ext_ptr buffer to store the extension of a file
*
* Returns : None
*
**************************************************************************************************************
*/
void FAT_GetSfnExt (volatile USB_INT08U *entry,
USB_INT08U *ext_ptr)
{
USB_INT32U cnt;
cnt = 0;
while (cnt < 8) { /* Goto the beginning of the file extension */
entry++;
cnt++;
}
cnt = 0;
while (cnt < 3) { /* Get 3 charecters from there */
*ext_ptr = *entry;
ext_ptr++;
entry++;
cnt++;
}
*ext_ptr = 0;
ext_ptr--;
while (*ext_ptr == ' ') { /* If any spaces exist after the file extension, replace them with 0 */
*ext_ptr = 0;
ext_ptr--;
}
}
/*
**************************************************************************************************************
* CASE INSENSITIVE COMPARISION OF STRINGS
*
* Description: This function compares two strings case insensitively
*
* Arguments : str1 Pointer to the first string
* str2 Pointer to the second string
*
* Returns : MATCH_FOUND if both the strings are same
* NATCH_NOT_FOUND if both the strings are different
*
**************************************************************************************************************
*/
USB_INT32S FAT_StrCaseCmp (USB_INT08U *str1,
USB_INT08U *str2)
{
while (*str1 && *str2) {
if (*str1 == *str2 || *str1 == (*str2 + 32) || *str1 == (*str2 - 32)) {
str1++;
str2++;
continue;
} else {
return (MATCH_NOT_FOUND);
}
}
if (*str1 == 0 && *str2 == 0) {
return (MATCH_FOUND);
} else {
return (MATCH_NOT_FOUND);
}
}
/*
**************************************************************************************************************
* CHECK TYPE OF THE ENTRY
*
* Description: This function checks the type of file entry.
*
* Arguments : ent Pointer to the buffer containing the entry
*
* Returns : LAST_ENTRY if the entry is last entry
* FREE_ENTRY if the entry is free entry
* LFN_ENTRY if the entry is long file name entry
* SFN_ENTRY if the entry is short file name entry
*
**************************************************************************************************************
*/
USB_INT32U FAT_ChkEntType (volatile USB_INT08U *ent)
{
if (ent[0] == 0x00) { /* First byte is 0 means it is the last entry */
return (LAST_ENTRY);
}
if (ent[0] == 0xE5) { /* First byte is 0xE5 means it is the free entry */
return (FREE_ENTRY);
}
if (0x0F == ent[11]) { /* If 11th byte of an entry is 0x0F, it is LFN */
return (LFN_ENTRY);
} else {
return (SFN_ENTRY); /* Else it is the SFN */
}
}
/*
**************************************************************************************************************
* READ DATA REQUESTED BY THE USER
*
* Description: This function reads data requested by the application from the file pointed by file descriptor.
*
* Arguments : fd file descriptor that points to a file
* buffer buffer into which the data is to be read
* num_bytes number of bytes requested by the application
*
* Returns : total_bytes_read Total bytes actually read.
*
**************************************************************************************************************
*/
USB_INT32U FILE_Read ( USB_INT32S fd,
volatile USB_INT08U *buffer,
USB_INT32U num_bytes)
{
USB_INT32U total_bytes_to_read; /* Total bytes requested by the application */
USB_INT32U total_bytes_read; /* Total bytes read */
USB_INT32U bytes_read; /* Bytes read from one cluster */
USB_INT32U bytes_to_read; /* Bytes to be read in one cluster */
FILE_ENTRY *entry; /* Entry that contains the file attribute information */
USB_INT16U next_clus; /* Next cluster of the current cluster in the cluster chain */
entry = &FAT_FileEntry[fd-1]; /* Get file entry from file descriptor */
total_bytes_read = 0;
if (entry->FileSize == 0) {
return (0);
}
if (num_bytes < entry->FileSize) {
total_bytes_to_read = num_bytes;
} else {
total_bytes_to_read = entry->FileSize;
}
do {
next_clus = FAT_GetNextClus(entry->CurrClus); /* Get next cluster */
if (next_clus == 0) { /* If the current cluster is the last cluster */
/* If the offset is at the end of the file */
if (entry->CurrClusOffset == (entry->FileSize % FAT_BootSec.BytsPerClus)) {
return (0); /* No more bytes to read */
} /* If requested number is > remaining bytes in the last cluster */
if (total_bytes_to_read > ((entry->FileSize % FAT_BootSec.BytsPerClus) - entry->CurrClusOffset)) {
total_bytes_to_read = (entry->FileSize % FAT_BootSec.BytsPerClus) - entry->CurrClusOffset;
}
bytes_to_read = total_bytes_to_read;
/* If requested number is > remaining bytes in the current cluster */
} else if (total_bytes_to_read > (FAT_BootSec.BytsPerClus - entry->CurrClusOffset)) {
bytes_to_read = FAT_BootSec.BytsPerClus - entry->CurrClusOffset;
} else {
bytes_to_read = total_bytes_to_read;
}
bytes_read = FAT_ClusRead(entry->CurrClus, /* Read bytes from a single cluster */
entry->CurrClusOffset,
buffer,
bytes_to_read);
buffer += bytes_read;
total_bytes_read += bytes_read;
total_bytes_to_read -= bytes_read;
/* If the cluster offset reaches end of the cluster, make it 0 */
if (entry->CurrClusOffset + bytes_read == FAT_BootSec.BytsPerClus) {
entry->CurrClusOffset = 0;
} else {
entry->CurrClusOffset += bytes_read; /* Else increment the cluster offset */
}
if (entry->CurrClusOffset == 0) {
entry->CurrClus = (next_clus > 0) ? next_clus : entry->CurrClus;
}
} while (total_bytes_to_read);
return (total_bytes_read);
}
/*
**************************************************************************************************************
* READ FROM ONE CLUSTER
*
* Description: This function reads the data from a single cluster.
*
* Arguments : curr_clus Current cluster from which the data has to read
* clus_offset Position in the current cluster from which the data has to read
* buffer Buffer into which the data has to read
* num_bytes Number of bytes to read
*
* Returns : tot_bytes_read Total bytes read from the current cluster
*
**************************************************************************************************************
*/
USB_INT32U FAT_ClusRead ( USB_INT16U curr_clus,
USB_INT32U clus_offset,
volatile USB_INT08U *buffer,
USB_INT32U num_bytes)
{
USB_INT32U tot_bytes_read; /* total bytes read in the current cluster */
USB_INT32U n_bytes; /* Bytes to read in the current sector */
USB_INT32U start_sec; /* Starting sector of the current cluster */
USB_INT32U sec_num; /*Current sector number */
USB_INT16U num_sec; /* Number of sectors to be read */
USB_INT32U sec_offset; /* Offset in the current sector */
USB_INT32U cnt;
tot_bytes_read = 0;
start_sec = ((curr_clus - 2) * FAT_BootSec.SecPerClus) + FAT_BootSec.FirstDataSec;
sec_num = start_sec + (clus_offset / FAT_BootSec.BytsPerSec);
num_sec = num_bytes / FAT_BootSec.BytsPerSec;
sec_offset = clus_offset % FAT_BootSec.BytsPerSec;
if (sec_offset) { /* If the sector offset is at the middle of a sector */
MS_BulkRecv(sec_num, 1, FATBuffer); /* Read the first sector */
n_bytes = (FAT_BootSec.BytsPerSec - sec_offset <= num_bytes) ?
(FAT_BootSec.BytsPerSec - sec_offset) : num_bytes;
for (cnt = sec_offset; cnt < sec_offset + n_bytes; cnt++) {
*buffer = FATBuffer[cnt]; /* Copy the required bytes to user buffer */
buffer++;
}
tot_bytes_read += n_bytes;
clus_offset += n_bytes;
num_bytes -= n_bytes;
sec_num++;
}
if (num_bytes / FAT_BootSec.BytsPerSec) { /* Read all the remaining full sectors */
num_sec = num_bytes / FAT_BootSec.BytsPerSec;
MS_BulkRecv(sec_num, num_sec, buffer);
buffer += (num_sec * FAT_BootSec.BytsPerSec);
tot_bytes_read += (num_sec * FAT_BootSec.BytsPerSec);
clus_offset += (num_sec * FAT_BootSec.BytsPerSec);
num_bytes -= (num_sec * FAT_BootSec.BytsPerSec);
sec_num += num_sec;
}
if (num_bytes) { /* Read the last sector for the remaining bytes */
MS_BulkRecv(sec_num, 1, FATBuffer);
for (cnt = 0; cnt < num_bytes; cnt++) {
*buffer = FATBuffer[cnt]; /* Copy the required bytes to user buffer */
buffer++;
}
tot_bytes_read += num_bytes;
}
return (tot_bytes_read);
}
/*
**************************************************************************************************************
* WRITE THE DATA REQUESTED BY THE USER
*
* Description: This function writes data requested by the application to the file pointed by file descriptor
*
* Arguments : fd file descriptor that points to a file
* buffer buffer from which the data is to be written
* num_bytes number of bytes requested by the application
*
* Returns : total_bytes_written Total bytes actually written
*
**************************************************************************************************************
*/
USB_INT32U FILE_Write ( USB_INT32S fd,
volatile USB_INT08U *buffer,
USB_INT32U num_bytes)
{
USB_INT32U total_bytes_to_write; /* Total bytes requested by application */
USB_INT32U total_bytes_written; /* Total bytes written */
USB_INT32U bytes_written; /* Bytes written in a single cluster */
USB_INT32U bytes_to_write; /* Bytes to write in a single cluster */
FILE_ENTRY *entry; /* Entry that contains the file attribute information */
USB_INT16U free_clus; /* Free cluster available in the disk */
entry = &FAT_FileEntry[fd-1]; /* Get file entry from file descriptor */
total_bytes_written = 0;
total_bytes_to_write = num_bytes;
if (num_bytes) {
if (entry->FileSize == 0) {
free_clus = FAT_GetFreeClus();
FAT_UpdateFAT(free_clus, 0xFFFF);
entry->CurrClus = free_clus;
MS_BulkRecv(entry->EntrySec, 1, FATBuffer);
WriteLE16U(&FATBuffer[(entry->EntrySecOffset) + 26], free_clus);
MS_BulkSend(entry->EntrySec, 1, FATBuffer);
}
} else {
return (0);
}
entry->CurrClus = FAT_GetEndClus(entry->CurrClus); /* Make the current cluster as end cluster */
entry->CurrClusOffset = entry->FileSize % FAT_BootSec.BytsPerClus; /* Move cluster offset to file end */
do {
if (total_bytes_to_write > FAT_BootSec.BytsPerClus - entry->CurrClusOffset) {
bytes_to_write = FAT_BootSec.BytsPerClus - entry->CurrClusOffset;
} else {
bytes_to_write = total_bytes_to_write;
}
bytes_written = FAT_ClusWrite(entry->CurrClus,
entry->CurrClusOffset,
buffer,
bytes_to_write);
buffer += bytes_written;
total_bytes_written += bytes_written;
total_bytes_to_write -= bytes_written;
entry->FileSize += bytes_written;
if (entry->CurrClusOffset + bytes_written == FAT_BootSec.BytsPerClus) {
entry->CurrClusOffset = 0;
} else {
entry->CurrClusOffset += bytes_written;
}
if (entry->CurrClusOffset == 0) {
free_clus = FAT_GetFreeClus();
if (free_clus == 0) {
return (total_bytes_written);
}
FAT_UpdateFAT(entry->CurrClus, free_clus);
FAT_UpdateFAT(free_clus, 0xFFFF);
entry->CurrClus = free_clus;
}
} while (total_bytes_to_write);
return (total_bytes_written);
}
/*
**************************************************************************************************************
* WRITE TO ONE CLUSTER
*
* Description: This function writes the data to a single cluster.
*
* Arguments : curr_clus Current cluster into which the data has to write
* clus_offset Position in the current cluster from which the data has to write
* buffer Buffer from which the data has to write
* num_bytes Number of bytes to write
*
* Returns : tot_bytes_read Total bytes written into the current cluster
*
**************************************************************************************************************
*/
USB_INT32U FAT_ClusWrite ( USB_INT16U curr_clus,
USB_INT32U clus_offset,
volatile USB_INT08U *buffer,
USB_INT32U num_bytes)
{
USB_INT32U tot_bytes_written;
USB_INT32U n_bytes;
USB_INT32U start_sec;
USB_INT32U sec_num;
USB_INT16U num_sec;
USB_INT32U sec_offset;
USB_INT32U cnt;
tot_bytes_written = 0;
start_sec = ((curr_clus - 2) * FAT_BootSec.SecPerClus) + FAT_BootSec.FirstDataSec;
sec_num = start_sec + (clus_offset / FAT_BootSec.BytsPerSec);
num_sec = num_bytes / FAT_BootSec.BytsPerSec;
sec_offset = clus_offset % FAT_BootSec.BytsPerSec;
if (sec_offset) {
MS_BulkRecv(sec_num, 1, FATBuffer);
n_bytes = (FAT_BootSec.BytsPerSec - sec_offset <= num_bytes) ?
(FAT_BootSec.BytsPerSec - sec_offset) : num_bytes;
for (cnt = sec_offset; cnt < (sec_offset + n_bytes); cnt++) {
FATBuffer[cnt] = *buffer;
buffer++;
}
MS_BulkSend(sec_num, 1, FATBuffer);
tot_bytes_written += n_bytes;
clus_offset += n_bytes;
num_bytes -= n_bytes;
sec_num++;
}
if (num_bytes / FAT_BootSec.BytsPerSec) {
num_sec = num_bytes / FAT_BootSec.BytsPerSec;
MS_BulkSend(sec_num, num_sec, buffer);
buffer += (num_sec * FAT_BootSec.BytsPerSec);
tot_bytes_written += (num_sec * FAT_BootSec.BytsPerSec);
clus_offset += (num_sec * FAT_BootSec.BytsPerSec);
num_bytes -= (num_sec * FAT_BootSec.BytsPerSec);
sec_num += num_sec;
}
if (num_bytes) {
MS_BulkRecv(sec_num, 1, FATBuffer);
for (cnt = 0; cnt < num_bytes; cnt++) {
FATBuffer[cnt] = *buffer;
buffer++;
}
MS_BulkSend(sec_num, 1, FATBuffer);
tot_bytes_written += num_bytes;
}
return (tot_bytes_written);
}
/*
**************************************************************************************************************
* GET NEXT CLUSTER
*
* Description: This function returns next cluster of the current cluster in the cluster chain. If the current
* cluster is the last cluster then this function returns 0
*
* Arguments : clus_no The cluster number for which the next cluster to be found
*
* Returns : next_clus if the current cluster is not the last cluster
* 0 if the current cluster is the last cluster
* Note: In practical cluster number 0 doesn't exist
*
**************************************************************************************************************
*/
USB_INT16U FAT_GetNextClus (USB_INT16U clus_no)
{
USB_INT32U sec_num;
USB_INT32U ent_offset;
USB_INT16U next_clus;
/* Get the sector number in the FAT that contains current cluster */
sec_num = FAT_BootSec.RsvdSecCnt + ((clus_no * 2) / FAT_BootSec.BytsPerSec);
/* Get the sector offset in the FAT where the current cluster is located */
ent_offset = (clus_no * 2) % FAT_BootSec.BytsPerSec;
MS_BulkRecv(sec_num, 1, FATBuffer); /* Read that sector */
next_clus = ReadLE16U(&FATBuffer[ent_offset]); /* Read the next cluster */
if (next_clus >= 0xFFF8 && next_clus <= 0xFFFF) { /* If that value is in between 0xFFF8 and 0xFFFF */
next_clus = 0; /* Current cluster is the end cluster */
}
return (next_clus);
}
/*
**************************************************************************************************************
* GET FREE CLUSTER
*
* Description: This function returns the free cluster if available
*
* Arguments : None
*
* Returns : free_clus if available
* 0 if not available(means the disk is full)
*
**************************************************************************************************************
*/
USB_INT16U FAT_GetFreeClus (void)
{
USB_INT32U num_sec;
USB_INT32U cnt;
USB_INT32U sec_num;
USB_INT16U free_clus;
sec_num = FAT_BootSec.RsvdSecCnt;
num_sec = FAT_BootSec.FATSz16;
while (sec_num < (FAT_BootSec.RsvdSecCnt + num_sec)) {
MS_BulkRecv(sec_num, 1, FATBuffer);
for (cnt = 0; cnt < FAT_BootSec.BytsPerSec; cnt += 2) {
if (ReadLE16U(&FATBuffer[cnt]) == 0) {
free_clus = (((sec_num - FAT_BootSec.RsvdSecCnt) * FAT_BootSec.BytsPerSec) + cnt) / 2;
return (free_clus);
}
}
sec_num++;
}
return (0);
}
/*
**************************************************************************************************************
* UPDATE FILE ALLOCATION TABLE
*
* Description: This function updates the file allocation table
*
* Arguments : curr_clus Offset of the current cluster number in the file allocation table
* value Value with which this offset to be updated
*
* Returns : None
*
**************************************************************************************************************
*/
void FAT_UpdateFAT (USB_INT16U curr_clus,
USB_INT16U value)
{
USB_INT32U sec_num;
USB_INT32U sec_offset;
sec_num = FAT_BootSec.RsvdSecCnt + (curr_clus * 2) / FAT_BootSec.BytsPerSec;
sec_offset = (curr_clus * 2) % FAT_BootSec.BytsPerSec;
MS_BulkRecv(sec_num, 1, FATBuffer);
WriteLE16U(&FATBuffer[sec_offset], value);
MS_BulkSend(sec_num, 1, FATBuffer);
}
/*
**************************************************************************************************************
* UPDATE THE FILE ENTRY
*
* Description: This function updates the file entry that is located in the root directory
*
* Arguments : entry Pointer to the FILE ENTRY structure which contains the information about the file
*
* Returns : None
*
**************************************************************************************************************
*/
void FAT_UpdateEntry (FILE_ENTRY *entry)
{
USB_INT32U sec_num;
USB_INT32U offset;
sec_num = entry->EntrySec;
offset = entry->EntrySecOffset;
MS_BulkRecv(sec_num, 1, FATBuffer);
WriteLE32U(&FATBuffer[offset + 28], entry->FileSize);
MS_BulkSend(sec_num, 1, FATBuffer);
}
/*
**************************************************************************************************************
* CREATING AN ENTRY
*
* Description: This function creates a file entry in the root directory if the file does not exist
*
* Arguments : ent_name_given The file name with which the entry is to be created
* entry Pointer to FILE ENTRY structure
*
* Returns : OK If the entry already exists or successfully created if it doesn't exists
* ERROR If failed to create the entry
*
**************************************************************************************************************
*/
USB_INT32S FAT_CreateEntry (USB_INT08U *ent_name_given,
FILE_ENTRY *entry)
{
USB_INT32S rc;
rc = FAT_FindEntry(ent_name_given, entry); /* Find for the given file name in the root directory */
if (rc == MATCH_FOUND) { /* If match found, return */
return (rc);
} else {
rc = FAT_GetFreeEntry(entry); /* Else get a free entry from the root directory */
if (rc != OK) {
return (rc);
} else {
FAT_PutSFN(ent_name_given, entry); /* Store the given short file name in that entry */
return (rc);
}
}
}
/*
**************************************************************************************************************
* GET GREE ENTRY
*
* Description: This function searches for a free entry in the root directory. If a free entry is found, the
* sector number and sector offset where the entry is located will be stored
*
* Arguments : entry Pointer to FILE_ENTRY structure
*
* Returns : OK If a free entry is found
* ERROR If no free entry is found
*
**************************************************************************************************************
*/
USB_INT32S FAT_GetFreeEntry (FILE_ENTRY *entry)
{
USB_INT32U sec_num;
volatile USB_INT08U *buf;
USB_INT08U ent_type;
for (sec_num = FAT_BootSec.RootDirStartSec;
sec_num < (FAT_BootSec.RootDirStartSec + FAT_BootSec.RootDirSec);
sec_num++) {
MS_BulkRecv(sec_num, 1, FATBuffer);
buf = FATBuffer;
while (buf < (FATBuffer + FAT_BootSec.BytsPerSec)) {
ent_type = FAT_ChkEntType(buf);
if (ent_type == FREE_ENTRY) {
entry->EntrySec = sec_num;
entry->EntrySecOffset = buf - FATBuffer;
return (OK);
}
if (ent_type == LAST_ENTRY) {
return (ERR_ROOT_DIR_FULL);
} else {
buf += 32;
}
}
}
return (ERR_ROOT_DIR_FULL);
}
/*
**************************************************************************************************************
* PUT SHORT FILE NAME
*
* Description: This function fills the file entry with the short file name given by the user
*
* Arguments : ent_name_given File name given by the user
* entry Pointer to the FILE_ENTRY structure
*
* Returns : None
*
**************************************************************************************************************
*/
void FAT_PutSFN (USB_INT08U *ent_name_given,
FILE_ENTRY *entry)
{
USB_INT32U idx;
/* Read the sector from root directory containing the free entry */
MS_BulkRecv(entry->EntrySec, 1, FATBuffer);
for (idx = 0; idx < 8; idx++) { /* Fill the first eight charecters of the entry with file name */
if (*ent_name_given == '.') {
while (idx < 8) {
FATBuffer[entry->EntrySecOffset + idx] = 0x20;
idx++;
}
ent_name_given++;
} else {
FATBuffer[entry->EntrySecOffset + idx] = *ent_name_given;
ent_name_given++;
}
}
for (idx = 8; idx < 11; idx++) { /* Fill the next 3 charecters with file extension */
if (*ent_name_given == '.') {
while (idx < 11) {
FATBuffer[entry->EntrySecOffset + idx] = 0x20;
idx++;
}
} else {
FATBuffer[entry->EntrySecOffset + idx] = *ent_name_given;
ent_name_given++;
}
}
FATBuffer[entry->EntrySecOffset + idx] = 0x20;
for (idx = 12; idx < 32; idx++) { /* Fill all the remaining bytes with 0's */
FATBuffer[entry->EntrySecOffset + idx] = 0;
}
MS_BulkSend(entry->EntrySec, 1, FATBuffer); /* Write the sector into the root directory */
}
/*
**************************************************************************************************************
* FILE CLOSE
*
* Description: This function closes the opened file by making all the elements of FILE_ENTRY structure to 0
*
* Arguments : fd File descriptor which points to the file to be closed
*
* Returns : None
*
**************************************************************************************************************
*/
void FILE_Close (USB_INT32S fd)
{
FILE_ENTRY *entry;
entry = &FAT_FileEntry[fd-1];
MS_BulkRecv(entry->EntrySec, 1, FATBuffer);
WriteLE32U(&FATBuffer[entry->EntrySecOffset + 28], entry->FileSize); /* Update the file size */
MS_BulkSend(entry->EntrySec, 1, FATBuffer);
entry->CurrClus = 0;
entry->CurrClusOffset = 0;
entry->FileSize = 0;
entry->EntrySec = 0;
entry->EntrySecOffset = 0;
entry->FileStatus = 0;
}
/*
**************************************************************************************************************
* GET END CLUSTER
*
* Description: This function end cluster in the cluster chain of a cluster
*
* Arguments : clus_no Starting cluster of the cluster chain in which end cluster to be found
*
* Returns : End cluster in the cluster chain
*
**************************************************************************************************************
*/
USB_INT16U FAT_GetEndClus (USB_INT16U clus_no)
{
USB_INT16U next_clus;
next_clus = clus_no;
while (next_clus) {
next_clus = FAT_GetNextClus(clus_no);
if (next_clus) {
clus_no = next_clus;
}
}
return (clus_no);
}