文件系统资料文档格式.docx

文件系统资料文档格式.docx

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FS_AssignMemory（）AssignsmemorytoPowerPacFileSystem.

FS_LOGVOL_Create（）Createsalogicalvolume.

FS_LOGVOL_AddDevice（）Addsadevicetoalogicalvolume.

FS_GetMaxSectorSize（）Returnsthemaximumsectorsize.

FS_SetMaxSectorSize（）Configuresthemaximumsectorsize.

FS_SetMemHandler（）Setsthememoryallocationroutineswhenthefilesystemshalluse

externalmemoryallocationroutines.

FS_WriteUpdateDir（）Updatesthedirectoryentrywheneverafileiswrittento.

Fileaccessfunctions

FS_FClose（）Closesafile.

FS_FOpen（）Opensafile.

FS_FRead（）Readsdatafromafile.

FS_Read（）Readsdatafromafile.

FS_FWrite（）Writesdatatoafile.

FS_Write（）Writesdatatoafile.

Filepositioningfunctions

FS_FSeek（）Setspositionofafilepointer.

FS_FTell（）Returnspositionofafilepointer.

FS_GetFilePos（）Returnspositionofafilepointer.

FS_SetFilePos（）Setspositionofafilepointer.

Operationsonfiles

FS_CopyFile（）Copiesafile.

FS_GetFileAttributes（）Retrievestheattributesofagivenfile/directory.

FS_GetFileTime（）Retrievesthecreation,accessormodifytimestampofagivenfile/

directory.

FS_GetFileTimeExRetrievesthetimestampofagivenfile/directory.

FS_Move（）Movesanexistingfileoradirectory,includingitschildren.

FS_Remove（）Deletesafile.

FS_Rename（）Renamesafile/directory.

FS_SetFileAttributes（）Setstheattributesofagivenfileordirectory.

FS_SetFileTime（）Setsthetimestampofagivenfileordirectory.

FS_SetFileTimeEx（）Setsthecreation,accessormodifytimestampofagivenfileor

FS_SetEndOfFile（）Setstheendofafile.

FS_Truncate（）Truncatesafiletoaspecifiedsize.

FS_Verify（）Verifiesafilewithagivendatabuffer.

Directoryfunctions

FS_FindClose（）Closesadirectory.

FS_FindFirstFile（）Searchesforafileinaspecifieddirectory.

FS_FindNextFile（）Continuesfilesearchinadirectory.

FS_MkDir（）Createsadirectory.

FS_RmDir（）Removesadirectory.

Formattingamedium

FS_IsHLFormattedChecksifadeviceishigh-levelformatted.

FS_IsLLFormattedChecksifadeviceislow-levelformatted.

FS_FormatLLIfRequiredChecksifadeviceislow-levelformattedandformatsitifrequired.

FS_FormatLow（）Low-levelformatsadevice.

FS_Format（）High-levelformatsadevice.

Filesystemextendedfunctions

FS_GetFileSize（）Retrievesthecurrentfilesizeofagivenfilepointer.

FS_GetFreeSpace（）Getsamountoffreespaceondrive.

FS_GetNumVolumes（）Retrievestheavailablevolumes.

FS_GetTotalSpace（）Getstotalamountofdrivespace.

FS_GetVolumeFreeSpace（）Getsthefreespaceofagivenvolume.

FS_GetVolumeInfo（）Getvolumeinformation（clusters,sectorsetc.）.

FS_GetVolumeLabel（）Retrievesthelabelofagivenvolumeindex.

FS_GetVolumeName（）Retrievesthenameofagivenvolumeindex.

FS_GetVolumeSize（）Getsthesizeofagivenvolume.

FS_GetVolumeStatus（）Returnsthestatusofavolume.

FS_IsVolumeMounted（）Returnsifthevolumeismountedandhascorrectfilesystem

information.

FS_FileTimeToTimeStamp（）Convertsafiletimetoatimestamp.

FS_SetBusyLEDCallback（）SetsaBusyLEDcallbackforaspecificvolume.

FS_SetVolumeLabel（）Setsalabeltoaspecificvolume.

FS_TimeStampToFileTime（）Convertsatimestamptoafiletime.

Storagelayerfunctions

FS_STORAGE_GetDeviceInfo（）Returnsinformationaboutthedevice.

FS_STORAGE_Init（）InitializesthedriverandOSifnecessary.

FS_STORAGE_ReadSector（）Readsasectorfromadevice.

FS_STORAGE_ReadSectors（）Readsmultiplesectorsfromadevice.

FS_STORAGE_Sync（）Writescacheddatatothestoragemedium.

FS_STORAGE_Unmount（）Low-levelunmount.Unmountsavolumeonthedriverlayer.

FS_STORAGE_WriteSector（）Writesasectorfromadevice.

FS_STORAGE_WriteSectors（）Writesmultiplesectorsfromadevice.

FATrelatedfunctions

FS_FAT_CheckDisk（）ChecksandrepairsaFATvolume.

FS_FAT_CheckDisk_ErrCode2Text（）Returnsanerrormessagetoaspecificcheckdiskerrorcode.

FS_FAT_GrowRootDirLetstherootdirectoryofaFAT32volumegrow.

FS_FormatSD（）High-levelformatsadeviceaccordingtotheSDcardfilesystem

specification.

Filesystemcachefunctions

FS_AssignCache（）Addsacachetoaspecificdevice.

FS_CACHE_Clean（）Cleansthecachesandwritesdirtysectorstothevolume.

FS_CACHE_SetMode（）Setsthemodeforthecache.

FS_CACHE_SetQuota（）Setsthequotasforthedifferentsectortypesinthe

CacheRW_Quotacachemodule.

Error-handlingfunctions

FS_ClearErr（）Clearstheerrorstatusofagivenfilepointer.

FS_FEof（）Testsforend-of-fileonagivenfilepointer.

FS_FError（）Returnstheerrorcodeofagivenfilepointer.

FS_ErrorNo2Text（）Retrievestextforagivenerrorcode.

Obsoletefunctions

FS_CloseDir（）Closesadirectorystream.

FS_DirEnt2Attr（）Getsthedirectoryentryattributes.

FS_DirEnt2Name（）Getsthedirectoryentryname.

FS_DirEnt2Size（）Getsthedirectoryentryfilesize.

FS_DirEnt2Time（）Getsthedirectoryentrytimestamp.

FS_GetDeviceInfo（）Returnsinformationaboutthedevice.

FS_GetNumFiles（）Getsthenumberoffilesinadirectory.

FS_InitStorage（）InitializesthedriverandOSifnecessary.

FS_OpenDir（）Opensadirectorystream.

FS_ReadDir（）Readsthenextdirectoryentry.

FS_ReadSector（）Readsasectorfromadevice.

FS_RewindDir（）Resetsthepositionofthedirectorystream.

FS_WriteSector（）Writesasectortoadevice.

FS_UnmountLL（）Low-levelunmount.Unmountsavolumeonthedriverlayer.

Devicedrivers

PowerPacFileSystemhasbeendesignedtocooperatewithanykindofhardware.Tousespecifichardwarewith

PowerPacFileSystem,aso-calleddevicedriverforthathardwareisrequired.Thedevicedriverconsistsofbasic

I/Ofunctionsforaccessingthehardwareandaglobaltablethatholdspointerstothesefunctions.

Generalinformation

DEFAULTDEVICEDRIVERNAMES

Bydefault,thefollowingidentifiersareusedforeachdriver.

ToaddadrivertoPowerPacFileSystem,FS_AddDevice（）shouldbecalledwiththeproperidentifiertomountthe

devicedrivertoPowerPacFileSystembeforeaccessingthedeviceoritsunits.RefertoFS_AddDevice（）onpage35

fordetailedinformation.

UNITNUMBER

Mostdriverfunctionsaswellasmostoftheunderlyinghardwarefunctionsreceivetheunitnumberasthefirst

parameter.Theunitnumberallowsdifferentiationbetweenthedifferentinstancesofthesamedevicetypes.Ifthereare

forexample2NANDflasheswhichoperateas2differentdevices,thefirstoneisidentifiedasUnit=0,thesecondone

asUnit=1.Ifthereisjustasingleinstance（asinmostsystems）,theunitparametercanbeignoredbytheunderlying

hardwarefunctions.

RAMdiskdriver

PowerPacFileSystemcomeswithasimpleRAMdiskdriverthatmakesitpossibletouseaportionofyoursystem

RAMasadevicefordatastorage.Thiscanbeveryhelpfultoexamineyoursystemperformanceandmayalsobeused

asanin-systemtestprocedure.

SUPPORTEDHARDWARE

TheRAMdrivercanbeusedwitheverytargetwithenoughRAM.Thesizeofthediskisdefinedasthenumberof

sectorsreservedforthedrive.

THEORYOFOPERATION

ARAMdiskisaportionofmemorythatyouallocatetouseasapartition.TheRAMdiskdrivertakessomeofyour

memoryandpretendsthatitisaharddrivethatyoucanformat,mount,savefilesto,etc.

RememberthateverybitofRAMisimportantforthewellbeingofyoursystemandthelargeryourRAMdiskis,the

lessmemorythereisavailableforyoursystem.

FAIL-SAFEOPERATION

Whenpowerislost,thedataoftheRAMdriveistypicallylostaswellexceptforsystemswithBatterybackupforthe

RAMusedasstoragedevice.

Forthisreason,failsafetyisrelevantonlyforsystemswhichprovidesuchbatterybackup.

Unexpectedreset

Ifanunexpectedresetoccurs,thedatawillbepreserved.However,ifthepowerfailureoranunexpectedresetinterrupts

awriteoperation,thedataofthesectormaycontainpartiallyinvaliddata.

Powerfailure

Powerfailurecausesanunexpectedreset.Theeffectsofanunexpectedresetaredescribedabove.

WEARLEVELING

TheRAMdiskdriverdoesnotrequirewearleveling.

CONFIGURINGTHEDRIVER

AddingthedrivertoPowerPacFileSystem

Toaddthedriver,useFS_AddDevice（）withthedriverlabelFS_RAMDISK_Driver.Thisfunctionhastobe

calledfromwithinFS_X_AddDevices（）.RefertoFS_X_AddDevices（）onpage171formoreinformation.

Example

FS_AddDevice（&

FS_RAMDISK_Driver）;

FS_RAMDISK_Configure（）

Description

ConfiguresasingleRAMdiskinstance.

Prototype

voidFS_RAMDISK_Configure（U8Unit,

void*pData,

U16BytesPerSector,

U32NumSectors）;

Additionalinformation

Thesizeofthediskisdefinedasthenumberofsectorsreservedforthedrive.Eachsectorconsistsof512bytes.The

minimumvalueforNumSectorsis7.BytesPerSectordefinesthesizeofeachsectorontheRAMdisk.AFATfile

systemneedsaminimumsectorsizeof5