Porting linux on PPC405

John Linn John.Linn at xilinx.com
Fri Sep 5 01:26:49 EST 2008

Hi Vineeth,

I don't directly support that board, but it's similar to the ML405 in
that it uses a 405 processor.  Since I don't test on that board or any
V2Pro board, I'm going to tell you my experience on the ML405, a V4

See below.

> -----Original Message-----
> From: linuxppc-embedded-bounces+john.linn=xilinx.com at ozlabs.org
> bounces+john.linn=xilinx.com at ozlabs.org] On Behalf Of
vneethv at gmail.com
> Sent: Thursday, September 04, 2008 12:40 AM
> To: Linuxppc-embedded at ozlabs.org
> Subject: Porting linux on PPC405
> Hi all,
> I am trying to port Linux 2.6 on PPC405 processor.I have
> EDK 10.1,
> Xilinx University program board (with Virtex II Pro device)
> linux kernel from Xilinx git. (git.xilinx.com)
> Cross Compiler (Croostool)
> fdt.dts file generated by EDK using with help of Xilinx fdt patch.

This is typical of a dts file problem. You should compare the dts file
to the ml405.dts file that is in the xilinx git tree.

I just looked at a dts generator issue and see that the following
property on the processor is wrong as it can be 0 in the generated file.
This number below is for a system at 300 Mhz.

timebase-frequency = <300000000>;

> I could compile the kernel and could generate the zImage.
> I've downloaded the hardware bit file and then the zImage to the DDR
SDRAM on the board using
> Parallel 4 cable.
> when i give the RUN command, this is what i get..
> booting virtex
> memstart=0x0
> memsize=0x10000000
> zImage starting: loaded at 0x00400000 (sp: 0x00578f1c)
> Allocating 0x326564 bytes for kernel ...
> gunzipping (0x00000000 <- 0x0040c000:0x005772bb)...done 0x3015c8 bytes
> Linux/PowerPC load: console=ttyS0 ip=on root=/dev/ram
> Finalizing device tree... flat tree at 0x40ad68

Please also verify that you have specified the right amount of RAM for
the board in the dts file as that can cause a problem.  The memsize
shows 256 Mbyte, is that really correct?

The kernel could also be booting, but the console is at the wrong baud
rate as the UART in the device tree can be set to a baud rate that does
not agree with the boot args to the kernel.  No baud in the boot arg =
9600 baud.

I have some debug information on the wiki page at

> The booting process seems to be stopped after this. I the
bootarguments i've given are,
> In dts file,
> bootargs = "console=ttyS0 ip=off root=/dev/ram";
> linux,stdout-path="/plb at 0/serial at 83e00000";
> Please let me know if've missed smthing here..!
> n any clue on the reason why the boor process seems to be hanged here
> Thanks in advance,
> Vineeth
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