kernel/eka/include/drivers/crashflash.h
changeset 0 a41df078684a
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     1 // Copyright (c) 2006-2009 Nokia Corporation and/or its subsidiary(-ies).
       
     2 // All rights reserved.
       
     3 // This component and the accompanying materials are made available
       
     4 // under the terms of the License "Eclipse Public License v1.0"
       
     5 // which accompanies this distribution, and is available
       
     6 // at the URL "http://www.eclipse.org/legal/epl-v10.html".
       
     7 //
       
     8 // Initial Contributors:
       
     9 // Nokia Corporation - initial contribution.
       
    10 //
       
    11 // Contributors:
       
    12 //
       
    13 // Description:
       
    14 // e32/include/drivers/crashflash.h
       
    15 // 
       
    16 // WARNING: This file contains some APIs which are internal and are subject
       
    17 //          to change without notice. Such APIs should therefore not be used
       
    18 //          outside the Kernel and Hardware Services package.
       
    19 //
       
    20 
       
    21 #ifndef __CRASH_FLASH_H__
       
    22 #define __CRASH_FLASH_H__
       
    23 
       
    24 #include <e32def.h>
       
    25 #include <e32ver.h>
       
    26 #include <e32cmn.h>
       
    27 
       
    28 ///////////////////////////////////////////////////////////////////////////////
       
    29 //	Crash log is stored in flash in the format:
       
    30 //		Crash log size (TUint), i.e. bytes stored in crash log crash sector
       
    31 //		Crash log signature (string KCrashLogSignature)
       
    32 //		Uncompressed log size (TUint), if log is compressed
       
    33 //		Flags (TUint8) - bits 0-3 indicate log data format, bit 4 set when log 
       
    34 //						had to be truncated.
       
    35 //		If nand implementation, some white space is inserted to fill up
       
    36 //  	the whole of the signature block/sector
       
    37 //		Actual log data in specified format
       
    38 //*******WARNING*******: Crash log header each field must start/end on 4 byte 
       
    39 //						boundary, otherwise NOR flash implementations will hang
       
    40 ///////////////////////////////////////////////////////////////////////////////
       
    41 
       
    42 /** Maximum size of a crash log.
       
    43  * @internalTechnology
       
    44  */
       
    45 const TUint KMaxCrashLogSize = 0x00100000;// 1Meg of crashflash
       
    46 
       
    47 /** The size in bytes of the Crash Log Signature
       
    48  * @internalTechnology
       
    49  */
       
    50 const TUint KCrashLogSignatureBytes = 20;
       
    51 
       
    52 /** The size in bytes of the total size of the crash log (including itself and
       
    53  * the crash log signature)
       
    54  * @internalTechnology
       
    55  */
       
    56 const TUint KCrashLogSizeFieldBytes = 4;
       
    57 
       
    58 /* The crash log signature.
       
    59  * @internalTechnology
       
    60  */
       
    61 _LIT8(KCrashLogSignature, "Symbian Crash Logger");
       
    62 
       
    63 /** The size in bytes of the total size of the crash log once it has been uncompressed
       
    64  * @internalTechnology
       
    65  */
       
    66 const TUint KCrashLogUncompSizeFieldBytes = 4;
       
    67 
       
    68 /** The flags to indicate to the crash reader the data format of the log and if 
       
    69  *	it was truncated or not.  16 MSBs used to indicate the offset of the start of the
       
    70  *	log data from the signature, required for NAND flash implementations where signarture
       
    71  *	occupyies a whole flash sector/page filling unused space with white space
       
    72  * @internalTechnology
       
    73  */
       
    74 const TUint KCrashLogFlagsFieldBytes = 4;
       
    75 
       
    76 const TUint8 KCrashLogFlagUncompr = 0x0;/** No compression performed on log */
       
    77 const TUint8 KCrashLogFlagGzip = 0x1; 	/** Log compressed using Gzip compatible output*/
       
    78 const TUint8 KCrashLogFlagTypeBits = 4; /** No. of bits for the type*/
       
    79 
       
    80 const TUint8 KCrashLogFlagTruncated = 0x10; /** The log had to be truncated*/
       
    81 
       
    82 const TUint32 KCrashLogFlagOffShift = 16; /**place offset in 16 MSBs of flags field*/
       
    83 
       
    84 /** Total size of the crash log header in bytes.  Must be less than the size of a 
       
    85  *	single NAND flash sector/page for current crashflashnand implementations
       
    86  *	@internalTechnology
       
    87  */
       
    88 #ifndef _CRASHLOG_COMPR
       
    89 const TUint KCrashLogHeaderSize = KCrashLogSignatureBytes + KCrashLogSizeFieldBytes;
       
    90 #else
       
    91 const TUint KCrashLogHeaderSize = KCrashLogSignatureBytes + KCrashLogSizeFieldBytes + 
       
    92 									KCrashLogUncompSizeFieldBytes + KCrashLogFlagsFieldBytes;
       
    93 #endif //_CRASHLOG_COMPR
       
    94 
       
    95 
       
    96 /** The string to output when the log had to be truncated
       
    97  *	@internalTechnology
       
    98  */
       
    99 _LIT8(KCrashLogTruncated,"\r\nLog truncated due to end of crash log partition");
       
   100 
       
   101 /** Abstract class defining interface to all CrashFlash classes.  This is used
       
   102  * by the CrashLogger to log to a specific type of flash.
       
   103  *@internalTechnology
       
   104  */
       
   105 class CrashFlash
       
   106     {
       
   107 public:
       
   108 	/** Called first.  Should initialise underlying crash flash device to the
       
   109 	 * state that it can read, write, and erase.
       
   110 	 * @return KErrNone if successful.  Else, a system wide error code.
       
   111 	 */
       
   112 	virtual TInt Initialise()=0;
       
   113 
       
   114 	/** Called second.  Allows underlying implementation to set any flags
       
   115 	 * required to indicate that a transaction has started.
       
   116 	 */
       
   117 	virtual void StartTransaction()=0;
       
   118 
       
   119 	/** Called third.  Performs the operations necessary to erase a block of
       
   120 	 * flash large enough to store a log of KMaxCrashLogSize.
       
   121 	 */
       
   122 	virtual void EraseLogArea()=0;
       
   123 
       
   124 	/** Called last.  Commits any buffered data and sets the flag for the
       
   125 	 * underlying crash flash device indicating that the transaction finished
       
   126 	 * succesfully.
       
   127 	 */
       
   128 	virtual void EndTransaction()=0;
       
   129 
       
   130 	/** Writes aDes to the underlying crash flash device.  The underlying 
       
   131 	 * implementation may buffer as required.
       
   132 	 */
       
   133 	virtual void Write(const TDesC8& aDes)=0;
       
   134 
       
   135 	/** Writes aDes to the signature section of the underlying cras flash device.
       
   136 	 * The descriptor should include both the signature and the length written.
       
   137 	 */
       
   138 	virtual void WriteSignature(const TDesC8& aDes)=0;
       
   139 
       
   140 	/** Reads the next aDes.Length() characters and places them in aDes starting
       
   141 	 * from aDes[0].  The read position is modifiable using SetReadPos().  The
       
   142 	 * underlying implementation may buffer as required.
       
   143 	 */
       
   144 	virtual void Read(TDes8& aDes)=0;
       
   145 
       
   146 	/** Sets the internal state such that the next read will take place at
       
   147 	 * aPos bytes from the base address.
       
   148 	 */
       
   149 	virtual void SetReadPos(TUint aPos) = 0;
       
   150 	
       
   151 	/** Sets the internal state of the write position
       
   152 	* aPos bytes from the base address.
       
   153 	*/
       
   154 	virtual void SetWritePos(const TUint aPos) = 0;
       
   155 
       
   156 	/** Returns the number of bytes written to the flash.  This is used by
       
   157 	 * reading programs to figure out how much to read back.
       
   158 	 * @return The current total number of bytes written to flash.
       
   159 	 */
       
   160 	virtual TUint BytesWritten()=0;
       
   161 	
       
   162 	/**
       
   163 	 * Erases the data in a given flash block
       
   164 	 * @param aBlock The block to be erased
       
   165 	 */
       
   166 	virtual void EraseFlashBlock(const TUint aBlock) = 0;
       
   167 	
       
   168 #ifdef _CRASHLOG_COMPR
       
   169 	/** Get the amount of space availiable for crash log data only.
       
   170 		Not including the space required to output the signature message
       
   171 		@return The number of bytes allocated to the crash log data
       
   172 	*/
       
   173 	virtual TUint GetOutputLimit(void)=0;
       
   174 	
       
   175 	/** Get the offset from the end of the signature to the log data, if any.
       
   176 		@return The number of bytes after the signature that the log data starts
       
   177 	*/
       
   178 	virtual TUint GetLogOffset(void)=0;
       
   179 #endif
       
   180 	
       
   181 	};
       
   182 
       
   183 #endif