FlashFilesystemsUBIFS < DULG

%SECTION0{name=FlashFilesystemUBIFS}% UBI and UBIFS file systems

UBIFS is a flash filesystem, which work on top of the Linux MTD layer.
UBI itself is a software layer which basically is a volume management
and wear-leveling layer. It provides so called UBI volumes which is a
higher level abstraction than a MTD device.

For more documentation about UBI/UBIFS see:
   * linux source:Documentation/filesystems/ubifs.txt
   * http://www.linux-mtd.infradead.org/doc/ubi.html

This document illustrates the usage of UBI/UBIFS for the %BOARDNAME% board.

%SECTION1{name=LinuxCreateDeviceFiles}% Create Device Files

First we have to create some device files, which are necessary for using UBI/UBIFS:

%INCLUDE{DULGData_%BOARD%.LinuxUbiCreateDeviceFiles}%

%IF{ "%HAVE_UBI_NOR%" eq "true"}%
%SECTION1{name=LinuxUbiOnNOR}% Using UBI on NOR Flash

Erase the flash partition

%INCLUDE{DULGData_%BOARD%.LinuxUbiDeletePartitionNor}%

and attach it to UBI

%INCLUDE{DULGData_%BOARD%.LinuxUbiAttachNor}%

As this is done, we check if things are done correct:

%INCLUDE{DULGData_%BOARD%.LinuxUbiInfoNor}%

Now create a Volume on the UBI Device
As we intend to create just a single volume, we use maximum size ("-m"
option).

%INCLUDE{DULGData_%BOARD%.LinuxUbiCreateVolumeNor}%

Mount and use it:

%INCLUDE{DULGData_%BOARD%.LinuxUbiMountVolumeNor}%
%ENDIF%

%IF{ "%HAVE_UBI_NAND%" eq "true"}%
%SECTION1{name=LinuxUbiOnNAND}% Using UBI on NAND Flash:

Erase the flash partition:

%INCLUDE{DULGData_%BOARD%.LinuxUbiDeletePartitionNand}%

and attach it to UBI:

%INCLUDE{DULGData_%BOARD%.LinuxUbiAttachNand}%

As this is done, we check if things are done correct:

%INCLUDE{DULGData_%BOARD%.LinuxUbiInfoNand}%

Create a Volume on the UBI Device:

%INCLUDE{DULGData_%BOARD%.LinuxUbiCreateVolumeNand}%

As we intend to create just a single volume, we use maximum size ("-m"
option).

Mount and use it:

%INCLUDE{DULGData_%BOARD%.LinuxUbiMountVolumeNand}%

Check with "-a" option:

%INCLUDE{DULGData_%BOARD%.LinuxUbiInfoNorNand}%

List which partitions we have mounted, and how many space we have available:

%INCLUDE{DULGData_%BOARD%.LinuxUbidf}%

%ENDIF%


%SECTION1{name=LinuxUbiCreate}% Creating UBIFS File System Images

%SECTION2{name=LinuxUbiDetermineParameters}% Determining the Parameters of the used Flash Types:

The "mkfs.ubifs" requires a few parameters that describe the specific
features of the underlying flash chips. The easiest way to determine
these parameters is to run the "mtdinfo" utility on a running Linux
system. %IF{ "%HAVE_UBI_NOR%" eq "true"}% /dev/mtd%UBI_NOR_PART% is NOR flash ,%ENDIF% %IF{ "%HAVE_UBI_NAND%" eq "true"}%/dev/mtd%UBI_NAND_PART% is NAND flash%ENDIF%:

%INCLUDE{DULGData_%BOARD%.LinuxUbiMTDInfo}%

%IF{ "%HAVE_UBI_NOR%" eq "true"}%
%INCLUDE{DULGData_%BOARD%.LinuxUbiMTDInfoNor}%
%ENDIF%

%IF{ "%HAVE_UBI_NAND%" eq "true"}%
%INCLUDE{DULGData_%BOARD%.LinuxUbiMTDInfoNand}%
%ENDIF%

The interesting parameters are:
<pre>
- min-io-size:  corresponds to "Minimum input/output unit size"
- max-leb-cnt:  corresponds to "Amount of eraseblocks"
</pre>

One more needed parameter from the "ubinfo -a" command:
<pre>
- leb-size:     corresponds to "Logical eraseblock size"
</pre>

%SECTION2{name=LinuxUbiCreateTestFS}% Create some Test File System Hierarchy

%INCLUDE{DULGData_%BOARD%.LinuxUbiCreateTestFS}%

%IF{ "%HAVE_UBI_NOR%" eq "true"}%
Create UBIFS Images for "%UBI_NOR_NAME%" (NOR)

%INCLUDE{DULGData_%BOARD%.LinuxUbiCreateImageNor}%
%ENDIF%

Create UBIFS Images for "%UBI_NAND_NAME%" (NAND)

%INCLUDE{DULGData_%BOARD%.LinuxUbiCreateImageNand}%

%SECTION2{name=LinuxUbiInstallImage}% Installing UBIFS images into existing UBI Volume:

%IF{ "%HAVE_UBI_NOR%" eq "true"}%
%INCLUDE{DULGData_%BOARD%.LinuxUbiInstallUbifsImageNor}%
%ENDIF%

%INCLUDE{DULGData_%BOARD%.LinuxUbiInstallUbifsImageNand}%

%SECTION2{name=LinuxUbiInstallImagesEmpty}% Installing UBI images (if no UBI Volumes exist):

If the UBI device is not already formatted to contain suitable
volumes, we have to generate UBI images.  An UBI image may contain one
or more UBI volumes, which in turn may be used to store an UBIFS file
system.  This is done using the "ubinize" tool, which unfortunately is
a bit weird to use: an input configuration ini-file defines all the
UBI volumes - their characteristics and the contents, but it does not
define the characteristics of the flash flash device - these have to
be specified as command-line options.

Also, we should keep in mind that we should no longer use
"flash_eraseall" to erase the MTD device, as this has no knowledge
about the UBI erase counters.  Instead, we should use "ubiformat" to
erase the flash and install a new UBI image.


Unmount and detach previously used UBI devices:

%IF{ "%HAVE_UBI_NOR%" eq "true"}%
%INCLUDE{DULGData_%BOARD%.LinuxUbiUmountVolumeNor}%
%ENDIF%

%INCLUDE{DULGData_%BOARD%.LinuxUbiUmountVolumeNand}%


Create UBI ini-file and create UBI images:

Note: for the volume sizes we use the byte count previously determined
by running "ubinfo -a" above.

%IF{ "%HAVE_UBI_NOR%" eq "true"}%
%INCLUDE{DULGData_%BOARD%.LinuxUbiIniFileNor}%
%ENDIF%

%INCLUDE{DULGData_%BOARD%.LinuxUbiIniFileNand}%

Note that for the NAND device we must pass the "-s 2048" option to
ubinize; if we don't, an attempt to attach the created UBI device
will result in error messages like these:

%INCLUDE{DULGData_%BOARD%.LinuxUbiAttachErrorNand}%

For background information please see
http://www.linux-mtd.infradead.org/faq/ubi.html#L_vid_offset_mismatch

Erase MTD partitions and install UBI images:

%IF{ "%HAVE_UBI_NOR%" eq "true"}%
%INCLUDE{DULGData_%BOARD%.LinuxUbiFormatNor}%
%ENDIF%

%INCLUDE{DULGData_%BOARD%.LinuxUbiFormatNand}%

Verify that it worked:

%IF{ "%HAVE_UBI_NOR%" eq "true"}%
%INCLUDE{DULGData_%BOARD%.LinuxUbiFormatVerifyNor}%
%ENDIF%

%INCLUDE{DULGData_%BOARD%.LinuxUbiFormatVerifyNand}%