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/**************************************************************************/
/* */
/* Copyright (c) Microsoft Corporation. All rights reserved. */
/* */
/* This software is licensed under the Microsoft Software License */
/* Terms for Microsoft Azure RTOS. Full text of the license can be */
/* found in the LICENSE file at https://aka.ms/AzureRTOS_EULA */
/* and in the root directory of this software. */
/* */
/**************************************************************************/
/**************************************************************************/
/**************************************************************************/
/** */
/** FileX Component */
/** */
/** Utility */
/** */
/**************************************************************************/
/**************************************************************************/
#define FX_SOURCE_CODE
/* Include necessary system files. */
#include "fx_api.h"
#ifdef FX_ENABLE_EXFAT
#include "fx_system.h"
#include "fx_media.h"
#include "fx_utility.h"
#include "fx_directory_exFAT.h"
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _fx_utility_exFAT_bitmap_initialize PORTABLE C */
/* 6.1 */
/* AUTHOR */
/* */
/* William E. Lamie, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function initializes bitmap for exFAT volume. */
/* */
/* INPUT */
/* */
/* media_ptr Media control block pointer */
/* */
/* OUTPUT */
/* */
/* return status */
/* */
/* CALLS */
/* */
/* Media driver */
/* _fx_utility_exFAT_bitmap_free_cluster_find */
/* Find free cluster */
/* _fx_utility_exFAT_bitmap_cache_update Read bitmap cache */
/* _fx_utility_exFAT_bitmap_start_sector_get */
/* Get the bitmap starting sector*/
/* _fx_utility_exFAT_cluster_state_get Get cluster state */
/* */
/* CALLED BY */
/* */
/* FileX System Functions */
/* */
/* RELEASE HISTORY */
/* */
/* DATE NAME DESCRIPTION */
/* */
/* 05-19-2020 William E. Lamie Initial Version 6.0 */
/* 09-30-2020 William E. Lamie Modified comment(s), */
/* resulting in version 6.1 */
/* */
/**************************************************************************/
UINT _fx_utility_exFAT_bitmap_initialize(FX_MEDIA *media_ptr)
{
UINT status;
ULONG cluster;
UCHAR cluster_state;
ULONG bitmap_cache_size;
ULONG bitmap_size_in_bytes;
ULONG bitmap_size_in_sectors;
ULONG bitmap_total_size_in_bytes;
/* Calculate exFAT bitmap size. */
bitmap_size_in_bytes = DIVIDE_TO_CEILING(media_ptr -> fx_media_total_clusters, BITS_PER_BYTE);
bitmap_size_in_sectors = DIVIDE_TO_CEILING(bitmap_size_in_bytes, media_ptr -> fx_media_bytes_per_sector);
/* Align bitmap size by sectors size. */
bitmap_total_size_in_bytes = bitmap_size_in_sectors << media_ptr -> fx_media_exfat_bytes_per_sector_shift;
/* Set default bitMap cache size. */
bitmap_cache_size = media_ptr -> fx_media_bytes_per_sector * FX_EXFAT_BIT_MAP_NUM_OF_CACHED_SECTORS;
/* Do not use the memory if it not required. */
if (bitmap_cache_size > bitmap_total_size_in_bytes)
{
/* Adjust the cache size. */
bitmap_cache_size = bitmap_total_size_in_bytes;
}
/* Try to find BitMap start sector. */
status = _fx_utility_exFAT_bitmap_start_sector_get(media_ptr, &media_ptr -> fx_media_exfat_bitmap_start_sector);
/* Did we get the starting sector? */
if (status == FX_SUCCESS)
{
/* Yes, setup the media cache parameters. */
media_ptr -> fx_media_exfat_bitmap_cache_size_in_sectors =
bitmap_cache_size >> media_ptr -> fx_media_exfat_bytes_per_sector_shift;
media_ptr -> fx_media_exfat_bitmap_cache_dirty = FX_FALSE;
media_ptr -> fx_media_exfat_bitmap_cache_start_cluster = FX_FAT_ENTRY_START;
/* Calculate how many clusters mapped in the one sector. */
media_ptr -> fx_media_exfat_bitmap_clusters_per_sector_shift =
media_ptr -> fx_media_exfat_bytes_per_sector_shift +
BITS_PER_BYTE_SHIFT;
/* Start at initial cluster. */
cluster = FX_FAT_ENTRY_START;
/* Read first portion of BitMap. */
status = _fx_utility_exFAT_bitmap_cache_update(media_ptr, cluster);
/* Was the BitMap read successful? */
if (status == FX_SUCCESS)
{
/* Find first free cluster. */
status = _fx_utility_exFAT_bitmap_free_cluster_find(media_ptr, cluster, &cluster);
/* Did we find a free cluster? */
if (status == FX_SUCCESS)
{
/* Save first free cluster number. */
media_ptr -> fx_media_cluster_search_start = cluster;
/* Calculate number of free clusters from first free cluster. */
while (cluster < media_ptr -> fx_media_total_clusters + FX_FAT_ENTRY_START)
{
/* Get the state of the cluster. */
status = _fx_utility_exFAT_cluster_state_get(media_ptr, cluster, &cluster_state);
/* Was the state get successful? */
if (status != FX_SUCCESS)
{
/* No, get out of the loop. */
break;
}
/* Is the cluster free? */
if (FX_EXFAT_BITMAP_CLUSTER_FREE == cluster_state)
{
/* Yes, increment the available clusters. */
media_ptr -> fx_media_available_clusters++;
}
/* Move to next cluster. */
cluster++;
}
}
}
}
/* Return status. */
return(status);
}
#endif /* FX_ENABLE_EXFAT */
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