howto boot kernel from ubi volume?

[Lambrecht Jürgen]

On 09/28/2011 10:32 AM, Lambrecht Jürgen wrote:
>
> Hello,
>
> Because a NAND flash is not reliable, I don't want to write the kernel
> image raw to flash.
> Instead, I want to put it in an UBI volume.
>
> * The currently running kernel is written in barebox to
> /dev/nand0.kernel.bb, and the ubi rootfs image to /dev/nand0.root.bb; I
> have a free partition in /dev/nand0.diag.bb.
> * So I in a running kernel (v3.0-rc6) I formatted an ubi partition (on
> that nand0.diag.bb mtd3), and created 2 volumes (kernel and rootfs).
> Then I tftp'd a zImage to the kernel volume - the same zImage that is
> currently running.
> * Then in barebox: 'barebox:/dev ubiattach nand0.diag' gives:
> UBI: attaching mtd0 to ubi0
> UBI: physical eraseblock size:   131072 bytes (128 KiB)
> UBI: logical eraseblock size:    129024 bytes
> UBI: smallest flash I/O unit:    2048
> UBI: sub-page size:              512
> UBI: VID header offset:          512 (aligned 512)
> UBI: data offset:                2048
> registering /dev/ubi0
> registering kernel as /dev/ubi0.kernel
> registering rootfs as /dev/ubi0.rootfs
> UBI: attached mtd0 to ubi0
> UBI: MTD device name:            "nand0.diag"
> UBI: MTD device size:            48 MiB
> UBI: number of good PEBs:        384
> UBI: number of bad PEBs:         0
> UBI: max. allowed volumes:       128
> UBI: wear-leveling threshold:    4096
> UBI: number of internal volumes: 1
> UBI: number of user volumes:     2
> UBI: available PEBs:             3
> UBI: total number of reserved PEBs: 381
> UBI: number of PEBs reserved for bad PEB handling: 3
> UBI: max/mean erase counter: 19/0
> * Then I set bootargs correct
> * Then 'barebox:/dev bootz ubi0.kernel' gives:
> ubi_volume_cdev_read: 48 @ 0x00000000
> invalid magic 0x0001f800
>
> Why is that?
> My barebox version is 2010.12.0.
> Could it be because the mtd-utils used in linux is 1.4.6 (both on the
> target and the host (my laptop)), and the one in barebox is older?
>
> FYI: When I create an empty ubi volume in linux, and try to tftp to it
> in barebox, I get this error:
> (and the same error with ubimkvol)
>
> barebox:/ tftp zImage /dev/ubi0.kernel
> error frame: 0xa3b05828 0x00000882
> TFTP from server 10.0.56.4 ('zImage' -> '/dev/ubi0.kernel')
>          UBI error: ubi_io_write: error -5 while writing 512 bytes to
> PEB 0:512, written 0 bytes
>
Maybe this is the answer here.  I will try it out next week.
http://www.linux-mtd.infradead.org/faq/ubi.html#L_subpage_verify_fail

Juergen
>
> UBI warning: ubi_eba_write_leb: failed to write VID header to LEB
> 2147479551:0, PEB 0
> UBI: try another PEB
> UBI error: ubi_io_write: error -5 while writing 512 bytes to PEB 0:512,
> written 0 bytes
> UBI warning: ubi_eba_write_leb: failed to write VID header to LEB
> 2147479551:0, PEB 0
> UBI: try another PEB
> UBI error: ubi_io_write: error -5 while writing 512 bytes to PEB 0:512,
> written 0 bytes
> UBI warning: ubi_eba_write_leb: failed to write VID header to LEB
> 2147479551:0, PEB 0
> UBI: try another PEB
> UBI error: ubi_io_write: error -5 while writing 512 bytes to PEB 0:512,
> written 0 bytes
> UBI warning: ubi_eba_write_leb: failed to write VID header to LEB
> 2147479551:0, PEB 0
> UBI warning: ubi_ro_mode: switch to read-only mode
> Cannot start volume update
> write: Read-only file system
> \
> tftp failed: error -30
>
>
> Kind regards,
> Jürgen
>
> Jürgen Lambrecht
> R&D Associate
> Tel: +32 (0)51 303045    Fax: +32 (0)51 310670
> http://www.televic-rail.com
> Televic Rail NV - Leo Bekaertlaan 1 - 8870 Izegem - Belgium
> Company number 0825.539.581 - RPR Kortrijk
>
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>


-- 
Jürgen Lambrecht
R&D Associate
Tel: +32 (0)51 303045    Fax: +32 (0)51 310670
http://www.televic-rail.com
Televic Rail NV - Leo Bekaertlaan 1 - 8870 Izegem - Belgium
Company number 0825.539.581 - RPR Kortrijk