Re: Linux on Virtex board with ARCH=powerpc

[Peter Mendham <petermendham@computing.dundee.ac.uk>]

Hi John,

Thanks for your reply, that's really helpful.  I'm actually using the 
mainline kernel, rather than the one from the xilinx git tree, but your 
information has really moved me on.  My first problem was that the 
Xilinx utility (from the git tree) for device tree dts generation didn't 
insert a "linux,stdout-path" node under "chosen".  I spotted that the 
ml403 example had this, so after adding it I got early console 
messages.  Everything now grinds to a halt after I get the message "flat 
tree at 0x40ad60" which is just before it calls the kernel, so I assume 
it's that call that is killing it.  I have "console=ttyUL0" for my 
uartlite, so I should be getting messages, shouldn't I?  Do you know 
where the next execution point is?  Maybe I could find out where it's 
getting stuck.

I haven't managed to generate an ACE file, I'm just loading the kernel 
image from xmd ATM, genace won't play ball for me, it complains about 
-board user not being valid, it won't even run on the examples copied 
directly from the user manual.  Anyway, I think genace is a bit OT, and 
I can manage with xmd for now.

Thanks,
-- Peter

John Linn wrote:
> Hi Peter,
>
> I'm not up on what can be done with the simple image you refer to in 1.
> I'm sure I should be, but there's a lot to learn.
>
> With regards to 2, the elf image, zImage (without the elf extension), is
> located in arch/powerpc/boot.
>
> You can make a SystemACE file from that elf image just as you did in
> arch/ppc.  We have a default device tree file, ml405.dts, in the
> arch/powerpc/boot/dts directory for our ml405 board. The kernel
> configuration has a config, DEVICE_TREE, that specifies the name of the
> device tree file. I normally compile the device tree into the kernel
> which is the default build, make ARCH=powerpc zImage. That image does
> not require a boot loader.
>
> I inserted the text below from a document that I have about building the
> arch/ppc and arch/powerpc kernels.
>
> Hope that helps,
> John
>
>
> Notation
>
> The phrase "<ppc or powerpc>" is used throughput the text and means that
> one or the other, "ppc" or "powerpc" is to be typed depending on the
> architecture you are building.
>
> Commands that are used in a bash shell are preceded by ">".
>
> Getting Ready To Build the Kernel
>
> This assumes you installed the ELDK tools and assumes you'll be using a
> bash shell.
>
>   
>> bash
>> export CROSS_COMPILE=ppc_4xx-
>>     
>
> Setting Up the Kernel Tree
>
> If you have previously built this kernel for another architecture, ppc
> or powerpc, then the tree needs to be setup correctly for the new
> architecture.  Assuming you have not previously built it, this does not
> need to be done.
>
>   
>> make ARCH=<ppc or powerpc> mrproper
>>     
>
> Configuring the Kernel
>
> The kernel should be configured to run on the ML405 or ML507 board from
> Xilinx. 
> 	
>   
>> make ARCH=<ppc or powerpc>  ml405_defconfig
>>     
>
> or 
>
>   
>> make ARCH=<ppc or powerpc> ml507_defconfig
>>     
>
> Building the Kernel
>
> The following command will build the Linux kernel assuming you are in
> the root directory of the kernel.  The root directory of the kernel from
> the Xilinx Git tree is linux-2.6-xlnx. An elf file, zImage.elf, is
> created in the arch/ppc/boot/images directory for ppc architecture. An
> elf file, zImage, is created in the the arch/powerpc/boot directory for
> the powerpc architecture.
>
>   
>> make ARCH=<ppc or powerpc> zImage
>>     
> 	
> Building the Kernel With Ramdisk
>
> A ram disk image, a file named *.gz, must be placed into the
> arch/ppc/boot/images or arch/powerpc/boot directory, depending on the
> architecture, prior to building the kernel.
>
>   
>> make ARCH=<ppc or powerpc> zImage.initrd
>>     
>
> An elf file, zImage.initrd.elf, is created in arch/ppc/boot/images
> directory for the ppc architecture. An elf file file, zImage.initrd, is
> created in arch/powerpc/boot directory for the powerpc architecture.
>
> Generating An Ace File
>
> The elf file generated for the kernel and the bit stream can be combined
> to create an ACE file for compact flash.  The following assumes a bash
> shell where XMD is accessible and a xilinx probe attached to the board
> for which you are generating an ace file.
>
>   
>> xmd -tcl genace.tcl -jprog -target ppc_hw -hw <bit file name> -elf <elf
>>     
> file name> -board <ml405 or ml507> -ace <desired ace file name>
>
> -----Original Message-----
> From: linuxppc-embedded-bounces+john.linn=xilinx.com@ozlabs.org
> [mailto:linuxppc-embedded-bounces+john.linn=xilinx.com@ozlabs.org] On
> Behalf Of Peter Mendham
> Sent: Tuesday, June 24, 2008 3:02 AM
> To: linuxppc-embedded@ozlabs.org
> Subject: Linux on Virtex board with ARCH=powerpc
>
> Dear all,
>
> I'm trying to boot a 2.6.26-rc6 kernel on a custom Virtex 4 board.  I 
> have used the Xilinx utility to generate a device tree and now want to 
> generate an image for throwing onto CF for use with a SystemACE (just 
> like on the the ML3/4xx boards).  I don't want to use a bootloader (I 
> don't really need one).  I saw something on this list about simpleImage,
>
> "simple" sounded good to me so I thought I'd try that (or did I 
> misinterpret what this is for?).  I also don't want the image to be too 
> big, I always used to use a zImage under ARCH=ppc. So, two questions, 
> which hopefully are easy ones:
> 1. I did what Grant said in a post to this list about simpleImage, and 
> dumped my dts into arch/powerpc/boot/dts and I called it system.dts (for
>
> now).  I then tried to do make simpleImage.system which ran right 
> through to final link then moaned about a missing simpleboot-system.  
> Where is this supposed to come from?  What am I doing wrong?  I naively 
> tried copying simpleboot.o to simpleboot-system.o and the error went 
> away.  Hmm.
> 2. I need an ELF to give to my SystemACE file generator.  This used to 
> pop up in arch/ppc/boot/images and be called zImage.elf, which made 
> sense to me.  What's the deal now with powerpc?  What should I be using?
> Finally, can anyone give me a heads-up on any gotchas with what I'm 
> trying to do.  As you can tell, I don't entirely know what I'm doing, so
>
> any pointers would be gratefully received.
>
> Thanks,
> -- Peter
>
>
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