[ARMedslack] Anyone weigh in on Dreamplug install for 14.0?

Michael Langfinger slackware at langfinger.org
Tue Oct 2 18:47:33 UTC 2012

 Hi Innes,

 i had some spare time today to play around with my Dreamplug and the 
 new Slackware 14.0. I couldn't boot up the Dreamplug yet with the kernel 
 image that is provided by the slackware installer, but on my way trying 
 i found out some things you also might be interested in. :-)

 1.) U-Boot Upgrade:
 The original Dreamplug U-Boot is in fact very annoying, mainly because 
 of the missing ext2load support. I think we spoke about that and about 
 the workaround a while ago here on the mailing list. Anyway, you can 
 easily upgrade your U-Boot to a newer one. Just put u-boot.kwb and 
 uboot.elf from [1] on a vfat formatted usb flash drive (or any other 
 media you can access) and update u-boot with the following commands 
 (taken from [2]):

 WARNING: All u-boot variables will be erased in the process, including 
 the ethernet mac adresses! Don't forget to backup/restore them!

> usb start
> fatload usb 2 0x6400000 dreamplug/u-boot.kwb
> sf probe 0
> sf erase 0x0 0x80000
> sf write 0x6400000 0x0 0x${filesize}

 ${filesize} is the size that is displayed after executing the fatload 
 command. You have to convert the value into the corresponding hex value.

 You can now replace your vfat partition containing the kernel image 
 with an ext2 formatted partition. I tried this with my old Slackware 
 13.37 installation, worked fine.

 2.) Booting Slackware 14.0 Installer
 Unfortunately you can't boot the slackware installer even with the new 
 U-Boot version (i tried 2011.12-3 and 2012.04.01-2). There are two 
 different effects, depending on which machine id you set.

 a) Machine ID 3550/0xDDE (Dreamplug): The kernel won't boot and hangs 
 at "Uncompressing Linux... done, booting the kernel.". I first suspected 
 CONFIG_ARM_PATCH_PHYS_VIRT as source of the problem, but a patch for 
 this problem exists since february 2012 [1] and should be included in 
 the u-boot versions i tried. Also, the kernel boots if i set another 
 machid (see b)). Nevertheless, i haven't ruled this out yet. I will

 b) Machine ID 2659/0xA63 (Guruplug): The kernel starts booting and then 
 freezes, last line is "[    2.396407] brd: module loaded". I suppose 
 this is related to the known problem with probing the NAND flash 

 3.) Next steps?

 I see two possibilities on how to proceed:

 a) Build a custom kernel with NAND probing disabled and set the machine 
 id to the one that is also used by the Guruplug. I don't like this , but 
 it might be a quick workaround. You would also have to make sure that 
 you don't accidentally overwrite your custom kernel with the default one 
 from Slackware, because this would result in a non-bootable system.
 b) Find out what causes the kernel hang from 2a). This would mean that 
 you can set the machine id to the correct value and that you don't have 
 to use any workarounds.

 So, long story short: You still have to take a custom kernel to be able 
 to use Slackware on the Dreamplug, but you can now store your kernel 
 images on an ext2 partition if you update u-boot. I will have a look at 
 the u-boot sources that where used to build the u-boot images under [1] 
 later, maybe the patch for CONFIG_ARM_PATCH_PHYS_VIRT isn't included. If 
 this is the case, i will try to patch and build u-boot myself, maybe it 


 [1] http://people.debian.org/~tbm/u-boot/
 [2] http://wiki.debian.org/FreedomBox/Firmware
 [3] http://lists.denx.de/pipermail/u-boot/2012-February/117020.html

> Hi,
> I'm about to start upgrading my Dreamplug to Slackware 14.0.  Last 
> time
> I had problems with the 13.37 Slackware kernel because of MTD being
> enabled (kernel boot locks when it probes for NAND flash which isn't
> present on the Dreamplug), and also the lack of ext2load command in 
> the
> U-Boot.  I got over it by using the Guruplug arcnumber (2659), 
> putting
> the kernel + initrd on a local memory card which U-Boot could access,
> and using a generic kernel from another source which had no MTD 
> turned
> on.  That was about a year ago and it seems that while some things 
> have
> improved, others remain the same.
> The Dreamplug now has its own arcnumber (3550) although it seems like
> flattened device trees may have made that stuff irrelevant.  There is 
> a
> problem with CONFIG_ARM_PATCH_PHYS_VIRT which causes the apparent 
> hang
> at the Kernel Uncompressing... message which looks to be fixed in 
> later
> U-Boots.  However, I don't really see a clean U-Boot replacement for 
> the
> Dreamplug anywhere (Debian may have one but as I don't have access to 
> a
> copy of my current/original U-Boot image I'm not sure I want to go
> there).  The other issue with U-Boot is of course the booting direct
> from disk - which I'd love to do (and the SlackwareARM install 
> assumes
> you can do) but cannot with my current system.
> Before I dive in and experiment, has anyone got any insights into
> Dreamplug installs for Slackware 14.0 or am I too early?  I'd be 
> happy
> to continue with the current U-Boot and putting the kernel/initrd
> elsewhere for now, but does anyone know if the Slackware kernels can 
> be
> used on the Dreamplug directly, or whether I need to be looking for
> another one (or build my own)?
> Thanks,  Innes.
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