_mfs_error MFS_Flush_caches
(
MFS_DRIVE_STRUCT_PTR drive_ptr
)
{
#if MFSCFG_READ_ONLY
return MFS_NO_ERROR;
#else
_mfs_error error_code, return_code = MFS_NO_ERROR;
#if MFSCFG_READ_ONLY_CHECK
if (MFS_is_read_only (NULL, drive_ptr))
{
return return_code;
}
#endif
return_code = MFS_Flush_directory_sector_buffer(drive_ptr);
error_code = MFS_Flush_data_sector_buffer(drive_ptr);
if ( return_code == MFS_NO_ERROR ) return_code = error_code;
error_code = MFS_Flush_fat_cache(drive_ptr);
if ( return_code == MFS_NO_ERROR ) return_code = error_code;
return(return_code);
#endif
}
/*FUNCTION*-------------------------------------------------------------------
*
* Function Name : MFS_Read_data_sector
* Returned Value : error_code
* Comments :
* Readsone sector into the DATA_SECTOR buffer
*END*---------------------------------------------------------------------*/
_mfs_error MFS_Read_data_sector
(
MFS_DRIVE_STRUCT_PTR drive_ptr,
MFS_HANDLE_PTR handle, /*[IN] handle of the file for which we are doing the read/write */
uint_32 sector_number, /*[IN] sector number to read/write from/to file system medium */
boolean hw_read /*[IN] if read of a sector is needed or just validation of a new one */
)
{
_mfs_error error;
error = MFS_NO_ERROR;
if ( sector_number != drive_ptr->DATA_SECTOR_NUMBER )
{
MFS_Flush_data_sector_buffer(drive_ptr);
MFS_Invalidate_data_sector(drive_ptr);
if (hw_read)
{
error = MFS_Read_device_sector(drive_ptr,sector_number,drive_ptr->DATA_SECTOR_PTR);
}
else
{
error = MFS_NO_ERROR;
}
if ( error == MFS_NO_ERROR )
{
drive_ptr->DATA_SECTOR_NUMBER = sector_number;
}
}
return(error);
}
uint32_t MFS_Write
(
MFS_HANDLE_PTR handle,
MFS_DRIVE_STRUCT_PTR drive_ptr,
uint32_t num_bytes, /*[IN] number of bytes to be written */
char *buffer_address, /*[IN/OUT] bytes are written from this buffer */
_mfs_error_ptr error_ptr /*[IN/OUT] error code is written to this address */
)
{
uint32_t bytes_written;
uint32_t copy_size;
uint32_t cluster_offset;
uint32_t sector_number, sector_index;
uint32_t sector_offset;
uint32_t whole_sectors;
uint32_t cont_sectors;
uint32_t proc_sectors;
_mfs_error error, temp_error;
uint32_t file_size;
uint32_t next_cluster;
bool need_hwread;
uint32_t location;
uint32_t num_zeros;
uint32_t zeros_written;
uint32_t zero_size;
#if MFSCFG_READ_ONLY_CHECK
if (MFS_is_read_only (drive_ptr))
{
MFS_set_error_and_return(error_ptr,MFS_DISK_IS_WRITE_PROTECTED,0);
}
#endif
if ( buffer_address == NULL )
{
MFS_set_error_and_return(error_ptr,MFS_INVALID_PARAMETER,0);
}
if ( num_bytes == 0 )
{
MFS_set_error_and_return(error_ptr,MFS_NO_ERROR,0);
}
error = MFS_lock_dos_disk( drive_ptr );
if ( error != MFS_NO_ERROR )
{
MFS_set_error_and_return(error_ptr,error,0);
}
if ( handle->ACCESS == MFS_ACCESS_READ_ONLY )
{
MFS_unlock(drive_ptr,FALSE);
MFS_set_error_and_return(error_ptr,MFS_ACCESS_DENIED,0);
}
/*
** Setup the current cluster. If this is the first time writing to the file, a cluster needs to be added.
*/
if ( handle->CURRENT_CLUSTER == 0 )
{
handle->PREVIOUS_CLUSTER = 0;
handle->CURRENT_CLUSTER = clustoh(handle->DIR_ENTRY.HFIRST_CLUSTER, handle->DIR_ENTRY.LFIRST_CLUSTER);
if ( handle->CURRENT_CLUSTER==0 )
{
next_cluster = MFS_Find_unused_cluster_from(drive_ptr,drive_ptr->NEXT_FREE_CLUSTER);
if ( next_cluster != CLUSTER_INVALID )
{
clustod(handle->DIR_ENTRY.HFIRST_CLUSTER, handle->DIR_ENTRY.LFIRST_CLUSTER, next_cluster);
handle->TOUCHED = 1;
error = MFS_Put_fat(drive_ptr, next_cluster, CLUSTER_EOF);
if ( error == MFS_NO_ERROR )
{
handle->CURRENT_CLUSTER = next_cluster;
}
else
{
MFS_unlock(drive_ptr,FALSE);
MFS_set_error_and_return(error_ptr,error,0);
}
}
else
{
MFS_unlock(drive_ptr,FALSE);
MFS_set_error_and_return(error_ptr,MFS_DISK_FULL,0);
}
}
}
else if ( handle->CURRENT_CLUSTER == CLUSTER_EOF )
{
error = MFS_Add_cluster_to_chain(drive_ptr, handle->PREVIOUS_CLUSTER, &handle->CURRENT_CLUSTER);
if ( MFS_NO_ERROR != error )
{
MFS_unlock(drive_ptr,FALSE);
MFS_set_error_and_return(error_ptr,error,0);
}
}
else if ( handle->CURRENT_CLUSTER > drive_ptr->LAST_CLUSTER )
{
MFS_unlock(drive_ptr,FALSE);
MFS_set_error_and_return(error_ptr,MFS_DISK_FULL,0);
}
/* Make sure location (local variable) never points behind the end of file */
file_size = mqx_dtohl(handle->DIR_ENTRY.FILE_SIZE);
location = (handle->LOCATION > file_size) ? file_size : handle->LOCATION;
/* Calculate sector number and offsets within cluster and sector */
cluster_offset = OFFSET_WITHIN_CLUSTER(location);
sector_index = CLUSTER_OFFSET_TO_SECTOR(cluster_offset);
sector_number = CLUSTER_TO_SECTOR(handle->CURRENT_CLUSTER) + sector_index;
sector_offset = OFFSET_WITHIN_SECTOR(location);
/* Calculate possible gap to fill in by zeros if writing behind the end of file */
num_zeros = handle->LOCATION - location;
zeros_written = 0;
bytes_written = 0;
/* Write zeros to fill in gap if LOCATION points behind the end of file */
while (zeros_written < num_zeros)
{
/* If offset is non-zero, then reading the data is required */
error = MFS_Read_data_sector(drive_ptr, handle, sector_number, sector_offset != 0);
if ( error != MFS_NO_ERROR )
break;
/* Zero the buffer */
zero_size = min(num_zeros-zeros_written, drive_ptr->BPB.SECTOR_SIZE-sector_offset);
_mem_zero(&drive_ptr->DATA_SECTOR_PTR[sector_offset], zero_size);
drive_ptr->DATA_SECTOR_DIRTY = TRUE;
if ( drive_ptr->WRITE_CACHE_POLICY == MFS_WRITE_THROUGH_CACHE )
{
error = MFS_Flush_data_sector_buffer(drive_ptr);
if ( error != MFS_NO_ERROR )
break;
}
zeros_written += zero_size;
sector_offset += zero_size;
/*
** Check to see if we need to advance to the next sector, which has
** the side effect of increasing the cluster number if required.
*/
if ( sector_offset >= drive_ptr->BPB.SECTOR_SIZE )
{
temp_error = MFS_next_data_sector(drive_ptr, handle, §or_index, §or_number);
if (temp_error == MFS_EOF)
{
/* Always allocate new cluster, there is something to be written for sure */
error = MFS_Add_cluster_to_chain(drive_ptr, handle->PREVIOUS_CLUSTER, &handle->CURRENT_CLUSTER);
if ( MFS_NO_ERROR == error )
{
sector_number = CLUSTER_TO_SECTOR(handle->CURRENT_CLUSTER);
sector_index = 0;
}
}
else
{
error = temp_error;
}
sector_offset = 0;
}
}
/* Write partial sector if sector_offset is non-zero */
if ((sector_offset != 0) && (error == MFS_NO_ERROR))
{
/* Offset is non-zero, reading the data is required */
error = MFS_Read_data_sector(drive_ptr, handle, sector_number, TRUE);
if (error == MFS_NO_ERROR)
{
/* The requested lenght of data may span the sector to it's end */
copy_size = min(num_bytes, drive_ptr->BPB.SECTOR_SIZE-sector_offset);
_mem_copy(buffer_address, &drive_ptr->DATA_SECTOR_PTR[sector_offset], copy_size);
drive_ptr->DATA_SECTOR_DIRTY = TRUE;
if (drive_ptr->WRITE_CACHE_POLICY == MFS_WRITE_THROUGH_CACHE)
{
error = MFS_Flush_data_sector_buffer(drive_ptr);
}
if (error == MFS_NO_ERROR)
{
bytes_written = copy_size;
/*
** Check to see if we need to advance to the next sector, which has
** the side effect of increasing the cluster number if required.
*/
if ((sector_offset + bytes_written) >= drive_ptr->BPB.SECTOR_SIZE)
{
temp_error = MFS_next_data_sector(drive_ptr, handle, §or_index, §or_number);
/* Only an error if we are not done writing and can't extend the chain */
if (bytes_written < num_bytes)
{
if (temp_error == MFS_EOF)
{
/* Allocate new cluster */
error = MFS_Add_cluster_to_chain(drive_ptr, handle->PREVIOUS_CLUSTER, &handle->CURRENT_CLUSTER);
/* Update sector_number and index unconditionally - if there was an error the value is never used anyways. */
sector_number = CLUSTER_TO_SECTOR(handle->CURRENT_CLUSTER);
sector_index = 0;
}
else
{
error = temp_error;
}
}
}
}
}
}
/* Check whether the application buffer is properly aligned */
if ((((uint32_t)buffer_address+bytes_written) & drive_ptr->ALIGNMENT_MASK) == 0)
{
/* Yes, use zero copy approach */
whole_sectors = (num_bytes - bytes_written) >> drive_ptr->SECTOR_POWER;
while ((whole_sectors > 0) && (error == MFS_NO_ERROR))
{
cont_sectors = drive_ptr->BPB.SECTORS_PER_CLUSTER - sector_index;
if (cont_sectors > whole_sectors)
cont_sectors = whole_sectors;
error = MFS_Write_device_sectors(drive_ptr, sector_number, cont_sectors, MFSCFG_MAX_WRITE_RETRIES, buffer_address+bytes_written, &proc_sectors);
if (proc_sectors > 0)
{
bytes_written += proc_sectors * drive_ptr->BPB.SECTOR_SIZE;
whole_sectors -= proc_sectors;
/* Advance to next unprocessed sector */
sector_index += proc_sectors - 1;
temp_error = MFS_next_data_sector(drive_ptr, handle, §or_index, §or_number);
/* Go on only if we are not done writing yet */
if ((error == MFS_NO_ERROR) && (bytes_written < num_bytes))
{
if (temp_error == MFS_EOF)
{
/* Allocate new cluster */
error = MFS_Add_cluster_to_chain(drive_ptr, handle->PREVIOUS_CLUSTER, &handle->CURRENT_CLUSTER);
/* Update sector_number and index unconditionally - if there was an error the value is never used anyways. */
sector_number = CLUSTER_TO_SECTOR(handle->CURRENT_CLUSTER);
sector_index = 0;
}
else
{
error = temp_error;
}
}
}
}
}
