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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 */
/** */
/** Media */
/** */
/**************************************************************************/
/**************************************************************************/
#define FX_SOURCE_CODE
/* Include necessary system files. */
#include "fx_api.h"
#include "fx_media.h"
#include "fx_system.h"
FX_CALLER_CHECKING_EXTERNS
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _fxe_media_open PORTABLE C */
/* 6.1 */
/* AUTHOR */
/* */
/* William E. Lamie, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function checks for errors in the media open call. */
/* */
/* INPUT */
/* */
/* media_ptr Media control block pointer */
/* media_name Pointer to media name string */
/* media_driver Media driver entry function */
/* driver_info_ptr Optional information pointer */
/* supplied to media driver */
/* memory_ptr Pointer to memory used by the */
/* FileX for this media. */
/* memory_size Size of media memory - must */
/* at least 512 bytes and */
/* one sector size. */
/* media_control_block_size Size of FX_MEDIA structure */
/* */
/* OUTPUT */
/* */
/* FX_PTR_ERROR One or more input parameters */
/* are NULL */
/* status Actual completion status */
/* */
/* CALLS */
/* */
/* tx_thread_identify Get current thread */
/* tx_thread_preemption_change Disable/restore preemption */
/* _fx_media_open Actual media open service */
/* */
/* CALLED BY */
/* */
/* Application Code */
/* */
/* 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 _fxe_media_open(FX_MEDIA *media_ptr, CHAR *media_name,
VOID (*media_driver)(FX_MEDIA *), VOID *driver_info_ptr,
VOID *memory_ptr, ULONG memory_size, UINT media_control_block_size)
{
UINT status;
ULONG temp;
FX_MEDIA *current_media;
ULONG open_count;
#ifndef FX_SINGLE_THREAD
TX_THREAD *current_thread;
UINT old_threshold;
#endif
/* Check for invalid input pointers. */
if ((media_ptr == FX_NULL) || (media_driver == FX_NULL) || (memory_ptr == FX_NULL) || (media_control_block_size != sizeof(FX_MEDIA)))
{
return(FX_PTR_ERROR);
}
/* Check for a valid caller. */
FX_CALLER_CHECKING_CODE
/* Check for proper size of the logical sector cache. */
temp = _fx_system_media_max_sector_cache;
/* Isolate the lowest set bit. */
temp = (temp & ((~temp) + ((ULONG) 1)));
/* If FX_MAX_SECTOR_CACHE is a power of 2, the value of temp should be unchanged. */
if ((temp == 1) || (temp != _fx_system_media_max_sector_cache))
{
/* Not a power of 2, return an error. */
return(FX_MEDIA_INVALID);
}
/* Check for proper size of the FAT cache. */
temp = _fx_system_media_max_fat_cache;
/* Isolate the lowest set bit. */
temp = (temp & ((~temp) + ((ULONG) 1)));
/* If FX_MAX_FAT_CACHE is a power of 2, the value of temp should be unchanged. */
if ((temp == 1) || (temp != _fx_system_media_max_fat_cache))
{
/* Not a power of 2, return an error. */
return(FX_MEDIA_INVALID);
}
#ifndef FX_SINGLE_THREAD
/* Pickup current thread pointer. At this point we know the current thread pointer is non-null since
it was checked by code in FX_CALLER_CHECKING_CODE macro. */
current_thread = tx_thread_identify();
/* Disable preemption temporarily. */
tx_thread_preemption_change(current_thread, 0, &old_threshold);
#endif
/* Loop to check for the media already opened. */
current_media = _fx_system_media_opened_ptr;
open_count = _fx_system_media_opened_count;
while (open_count--)
{
/* Is the new media pointer already open? */
if (media_ptr == current_media)
{
#ifndef FX_SINGLE_THREAD
/* Restore preemption. */
tx_thread_preemption_change(current_thread, old_threshold, &old_threshold);
#endif
/* Duplicate media open, return an error! */
return(FX_PTR_ERROR);
}
/* Move to next entry. */
current_media = current_media -> fx_media_opened_next;
}
#ifndef FX_SINGLE_THREAD
/* Restore preemption. */
tx_thread_preemption_change(current_thread, old_threshold, &old_threshold);
#endif
/* Call actual media open service. */
status = _fx_media_open(media_ptr, media_name, media_driver, driver_info_ptr,
memory_ptr, memory_size);
/* Return status. */
return(status);
}