Nikita at 15:24, 22 September 2013

2013-09-22T15:24:04Z

Mike: JFFS2 images over UBI layer moved to Linux: JFFS2 images over UBI layer

2009-12-23T08:08:19Z

JFFS2 images over UBI layer moved to Linux: JFFS2 images over UBI layer

New page

On this page we assume, that you have MTD utils installed as described in [[Linux_Development_for_XScale_modules#MTD_utils|Linux Development for XScale modules]] article.

== Kernel support ==

In order to get UBI and UBI GLUE driver working you need to enable them in kernel configuration. In kernel configuration choose '''"Device Drivers -> Memory Technology Device (MTD) support -> UBI - Unsorted block images"''' menu and enable '''"Enable UBI"''' and '''"MTD devices emulation driver"''' options.
<pre>
┌─────────────────────────────────── UBI - Unsorted block images ────────────────────────────────────┐
│ Arrow keys navigate the menu. <Enter> selects submenus --->. Highlighted letters are hotkeys. │
│ Pressing <Y> includes, <N> excludes, <M> modularizes features. Press <Esc><Esc> to exit, <?> for │
│ Help, </> for Search. Legend: [*] built-in [ ] excluded <M> module < > module capable │
│ │
│ ┌────────────────────────────────────────────────────────────────────────────────────────────────┐ │
│ │ <*> Enable UBI │ │
│ │ (4096) UBI wear-leveling threshold │ │
│ │ (1) Percentage of reserved eraseblocks for bad eraseblocks handling │ │
│ │ <*> MTD devices emulation driver (gluebi) │ │
│ │ *** UBI debugging options *** │ │
│ │ [ ] UBI debugging │ │
│ │ │ │
│ └────────────────────────────────────────────────────────────────────────────────────────────────┘ │
├────────────────────────────────────────────────────────────────────────────────────────────────────┤
│ <Select> < Exit > < Help > │
└────────────────────────────────────────────────────────────────────────────────────────────────────┘
</pre>
Now you can build the kernel with UBI support including the UBI GLUE driver.

== User space tools ==

In this section we will use {{parameter|X}} as the MTD partition number attached to UBI, {{parameter|Y}} as the emulated MTD partition number and we assume that there were no MTD partitions attached to UBI before. <br>
To prepare the NAND for use with UBI, you should take the following steps:
* Erase the MTD partition that will be used for UBI volume(s):
<pre>
> flash_eraseall /dev/mtdX
</pre>
* Attach the MTD partition to UBI:
<pre>
> ubiattach /dev/ubi_ctrl -m X -O 2048
</pre>
* Create UBI volume:
<pre>
> ubimkvol /dev/ubi0 -m -N <ubi volume name>
</pre>
* Update the new UBI volume with JFFS2 image:
<pre>
> ubiupdatevol /dev/ubi0_0 <path to JFFS2 image>
</pre>
If you want to use the new UBI volume as the root filesystem on your device, you should change the {{parameter|root}} parameter of kernel command line to boot from emulated
MTD partition '''Y''' (which is UBI volume):
'''root=/dev/mtdblockY''' and add '''ubi.mtd=X,2048''' parameter, so the MTD partition containing the new UBI volume will be attached on kernel boot prior to root filesystem mount.

== UBI logical eraseblock size and JFFS2 image eraseblock size ==

UBI layer is using some part of NAND's ''physical'' erase block for it's own needs (e.g. bad blocks handling), therefore it provides a ''logical'' eraseblock for filesystem use. The logical eraseblock size is smaller than the physical, so when you construct the JFFS2/UBIFS image, as described in section [[Linux_Development_for_XScale_modules#JFFS2_images|JFFS2 images]] and [[Linux_Development_for_XScale_modules#UBIFS_images|UBIFS images]], you should set the {{parameter|eraseblock}} (JFFS2) and {{parameter|leb-size}} (UBIFS) parameter to UBI's logical eraseblock size. <br>
The UBI logical eraseblock size can be obtained by invoking the command:
<pre>
> cat /sys/class/ubi/ubiX/eraseblock_size
</pre>
Where {{parameter|X}} is the UBI device number.

== See also ==
* [[Linux_Development_for_XScale_modules|Linux Development for XScale modules]]
* [[Linux_MTD_drivers_on_CM-X270|Linux MTD drivers on CM-X270]]
* [[Getting_started_with_Linux_on_CM-X300|Getting started with Linux on CM-X300]]
* [http://www.linux-mtd.infradead.org/doc/ubi.html UBI documentation]
* [http://www.linux-mtd.infradead.org/faq/ubi.html UBI FAQ and HOWTO]

[[Category:Linux|JFFS2 images over UBI layer]]

@@ Line 1: / Line 1: @@
-On this page we assume, that you have MTD utils installed as described in [[Linux_Development_for_XScale_modules#MTD_utils|Linux Development for XScale modules]] article.
+On this page we assume that you have MTD utils installed as described in [[Linux_Development_for_XScale_modules#MTD_utils|Linux Development for XScale modules]] article.
 == Kernel support ==
-In order to get UBI and UBI GLUE driver working you need to enable them in kernel configuration. In kernel configuration choose '''"Device Drivers -> Memory Technology Device (MTD) support -> UBI - Unsorted block images"''' menu and enable '''"Enable UBI"''' and '''"MTD devices emulation driver"''' options.
+In order to get UBI and UBI GLUE driver working you need to enable them in kernel configuration. In kernel configuration choose '''"Device Drivers -> Memory Technology Device (MTD) support -> Enable UBI - Unsorted block images"''' menu and enable '''"Enable UBI"''' and '''"MTD devices emulation driver"''' options.
 <pre>
 ┌─────────────────────────────────── UBI - Unsorted block images ────────────────────────────────────┐
@@ Line 11: / Line 11: @@
 │                                                                                                    │
 │ ┌────────────────────────────────────────────────────────────────────────────────────────────────┐ │
-│ │             <*> Enable UBI                                                                     │ │
+│ │             <*> Enable UBI - Unsorted block image                                              │ │
 │ │             (4096) UBI wear-leveling threshold                                                 │ │
 │ │             (1)   Percentage of reserved eraseblocks for bad eraseblocks handling              │ │
 │ │             <*>   MTD devices emulation driver (gluebi)                                        │ │
 │ │             [ ]   UBI debugging                                                                │ │
 │ │                                                                                                │ │

Linux: JFFS2 images over UBI layer - Revision history

Nikita at 15:24, 22 September 2013

Mike: JFFS2 images over UBI layer moved to Linux: JFFS2 images over UBI layer