Booting base-hw image on a Freescale i.MX6

[Stefan Kalkowski]

Hi,

On 01/02/2014 08:52 AM, Aditya Kousik wrote:
> Hello all,
> 
> We've tried to run a basic test-printf script on a Freescale i.MX6
> sabrelite board. Based on
> this<http://sourceforge.net/p/genode/mailman/message/31760885/>,
> we implemented the necessary files. We had also come across an i.MX6 branch
> by Nikolay Golikov stating that he had a preliminary port of i.MX6 here:
> https://github.com/decaprox/genode/tree/i.mx6
> 
> We ran RUN_OPT="--target=uboot" make run/printf to see if it does print "-1
> = -1 = -1" to the serial console (tested with gtkterm).
> 
> We ran the boot image uImage through TFTP at load address 0x10800000. It
> loads the kernel (267.9 kB) but stops at "Loading kernel".

Assuming, your resulting kernel image is linked to 0x10001000, and ends
at about 0x102cbc55, like the result I got when compiling Nikolay's
branch, your load address for the u-boot uImage sounds reasonable.
Unfortunately, I can't reproduce your experiments, because I don't have
such a board available. The first thing that comes to my mind is, that
Nikolay used another board containing the i.MX6 SoC than you with
another memory layout of the related peripherals.

> 
> How do we know if the kernel is indeed running, or are we checking the
> right UART ports? (we checked UART1)

First at all, you should add a printf command like:

  PDBG("kernel started!")"

at the very beginning of the kernel's execution. In Nikolay's branch I
would add it here:


https://github.com/decaprox/genode/blob/i.mx6/base-hw/src/core/kernel.cc#L1366

If that message isn't printed, very likely your UART definitions aren't
correct.

> 
> I gave "console=ttymxc0, 115200" as bootargs in u-boot. Any suggestions on
> how to proceed? Because we are literally stuck.

Forget about "bootargs" in u-boot. They are specific to booting the
Linux kernel. U-boot puts them into the Linux/ARM specific ATAG
structure. In Genode that structure isn't used. It's hard coded in the
kernel, which UART is used for kernel/core debug messages. In Nikolay's
branch, he uses the UART with memory mapped I/O located at 0x02020000,
and with the following UART definition:


https://github.com/decaprox/genode/blob/i.mx6/base/include/drivers/uart/imx31_uart_base.h

Please check whether this corresponds with your board's definitions.

> 
> Also, is there a good debugging tool for testing the genode environment on
> direct hardware?

Well, there is JTAG of course, which isn't related to Genode
specifically. There are other debugging utils available on Genode, like
GDB, but that wouldn't help on that low level you're currently working at.

Regards
Stefan

> 
> Thanks in advance
> Aditya Kousik
> 
> 
> 
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-- 
Stefan Kalkowski
Genode Labs

http://www.genode-labs.com/ · http://genode.org/