[U-Boot-Users] Loading from a CF card on the PCMCIA interface

Rod Boyce rod_boyce at stratexnet.com
Wed Jan 22 20:24:59 CET 2003


I did not make myself clear enough.  I have following your instructions
about CF cards and U-Boot on your web site thank you very much it was a
great help.  I cannot read the Linux kernel using the command 'diskboot
200000 0:6' if would appear that when calculating the sector offset for this
partition the calculation is off by 32 sectors I have yet to determine the
significance of this as inside the extended partition the first Linux
partition is offset by 32 sectors.
But if I diskboot 200000 0:1 (or 0:2 or 0:3 all primary partitions) then all
is well.
I'm happy to provide debug output but I am not familiar enough with the DOS
partition scheme to see the answer clearly but I'm on the steep learning

Debug out below:
U-Boot# ide part

Partition Map for IDE device 0  --   Partition Type: DOS

Partition     Start Sector     Num Sectors     Type
ide_read dev 0 start 0, blocks 1 buffer at 1F9FA38
Powersaving 00
    1                   32            2144      83
    2                 2176            2176      83
    3                 4352            5248      83
    4                 9600          115584       5 Extd
ide_read dev 0 start 2580, blocks 1 buffer at 1F9F808
Powersaving 00
    5                 9632            7776      83
ide_read dev 0 start 4400, blocks 1 buffer at 1F9F5D8
Powersaving 00
    6                17440            2144      83
ide_read dev 0 start 4C80, blocks 1 buffer at 1F9F3A8
Powersaving 00
    7                19616            2144      83
ide_read dev 0 start 5500, blocks 1 buffer at 1F9F178
Powersaving 00
    8                21792            5216      83
ide_read dev 0 start 6980, blocks 1 buffer at 1F9EF48
Powersaving 00
    9                27040            7776      83
U-Boot# diskboot 200000 0:6
ide_read dev 0 start 0, blocks 1 buffer at 1F9F9E8
Powersaving 00
ide_read dev 0 start 2580, blocks 1 buffer at 1F9F7C0
Powersaving 00

Loading from IDE device 0, partition 6: Name: hda6
  Type: U-Boot
First Block: 17408,  # of blocks: 2176, Block Size: 512
ide_read dev 0 start 4400, blocks 1 buffer at 200000
Powersaving 00

** Bad Magic Number **

As you can see above from ide part partition 6 starts on sector 17440 but it
would seem that diskboot is calculating the start sector as 17408.  I'm
about to compare the differences between ide part and diskboot and see if
this produces any answers.

Rod Boyce

 -----Original Message-----
From: 	Wolfgang Denk [mailto:wd at denx.de] 
Sent:	Wednesday, 22 January 2003 6:54 p.m.
To:	Rod Boyce
Cc:	'u-boot-users at sourceforge.net'
Subject:	Re: [U-Boot-Users] Loading from a CF card on the PCMCIA

In message <8D7C5F56B409554D9D46AC22195807F3061C23 at exchwenz01.dmcwave.co.nz>
you wrote:
> I have a board with a compact flash device connected to the PCMCIA
> interface.  I am trying to read the Linux kernel out from a Linux
> situated inside an extended partition.

Use a separate (small - 2 MB or so) partition to store the Linux kernel.

> Has this been done before?  I can use diskboot on a primary partition fine
> but not from an extended partition.  Has anybody else done this before?

No. You would have to implement filesystem support to U-Boot.

But I would not like to see this integrated into U-Boot. If you  want
to do this, implement it as a U-Boot standalone application, that can
be used as second stage boot loader.

Best regards,

Wolfgang Denk

Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88  Email: wd at denx.de
It became apparent that one reason why the Ice Giants were  known  as
the  Ice  Giants  was  because they were, well, giants. The other was
that they were made of ice.              -Terry Pratchett, _Sourcery_

More information about the U-Boot mailing list