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Re: cirrus ep93xx support (was: Re: Debian ARM success story: Debian desktop on a TS-7300)

Lennert wrote:

(Or someone would have to
reverse engineer how the communication with the SD card works. 

My understanding is that the initrd (as distributed by Technologic Systems) has the kernel module needed to get the SD card working at boot time.  And Technologic Systems posts the source code for their custom kernel and modules here (this should contain the code needed to drive the SD card):

I found this here (which has other ARM-on-linux-related resources as well for their products):

I should also note here that the TS-7300 has an "interesting" boot process.  There is no kind of bios whatsoever on the TS-7300 that gives you flexibility when you're booting.  In other words, TS-7300 makes very simplistic assumptions when booting.  Here are those assumptions in a nutshell:
-When you power on the TS-7300, an SD card must be in the first slot.
-It basically assumes the SD card it will boot from is formatted just right, having special partitioning.
-The MBR must contain special code to quickly jump to the first partition. 
-The first partition must contain the kernel. 
-The second partition must contain the initrd. 
-That initrd must contain the driver to support the SD card. 
-The third partition must contain the / filesystem.

More details on this boot process are in the TS-7300 manual (See Section 2.3, which details the boot sequence):

Long story short, the TS-7300 can ONLY boot from an SD card.  Not from a boot floppy, nor a boot CD, nor an USB disk, nor from PXE boot, etc.  So if you MUST use an SD card to boot from, you'd need to image an installer directly onto an SD card (hypothetically with some future version Debian Installer on it).  And if you are going to be doing any imaging to an SD card at all, you might as well just image the ready-to-boot OS on there, not an installer.

So I think the question becomes: does Debian want to become an upstream distributor of a special image of Debian just for the TS-7300 (and other subsequent boards that use the same booting style)?  Or just continue to let Technologic Systems do it (and it takes them several months after a Debian release to release their own image to image onto an SD card)?

Technologic Systems does a good job of keeping their Debian image tight (barely fits on a 256 MB SD card but you can use that same image on larger cards, ie. I put it on a 2 GB SD card).  You can then just apt-get install or remove things once booted.  Watch out though, the root password is blank, AND they install an ssh server by default, AND the ssh server allows remote root logins!  So please remember to keep your network connection disconnected until you set a good root password upon that first boot ;)

Dustin Harriman

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