Re: i.MX27 ?

[James Robinson <jmrobinson3@verizon.net>]

On 01/27/2011 02:40 AM, Sascha Hauer wrote:
> Hi,
>
> On Wed, Jan 26, 2011 at 09:20:11AM +0100, Vanalme Filip wrote:
>> Hi,
>>
>> Anyone ported Barebox to Freescale's i.MX27PDK 3-stack ?  I'm new to
>> Barebox (or any bootloader...) and I try to port it for my i.MX27PDK,
>> but did not succeed yet. I don't get anything on the console port yet.
>> I took the i.MX27ADS as a reference, copied all its files to a new
>> board directory, and started adjusting the files. Via the debug board
>> of the i.MX27PDK (containing a CPLD), I should be able to turn on some
>> debug leds very early in the boot process, but even this did not
>> succeed (yet...). I made changes in board_init_lowlevel() of
>> lowlevel_init.S to initialize the hardware. I guess
>> board_init_lowlevel() is one of the first functions that is executed.
>> Correct ?  Because I didn't get it up and running, I tried to do
>> debugging with a PEEDI debugger. Anyone experience with it for
>> debugging Barebox ? I'm using PEEDI in combination with Eclipse
>> (Zylin) debugger. It looks like I have problems when trying to step in
>> assembler sources...
> As a first step I would try to use barebox as a second stage loader
> behind U-Boot or redboot or whatever is on your board. What do you have
> on your board?
> When using barebox as a second stage loader you can comment out
> everything in board_init_lowlevel. Provided that you are using the
> correct UART you should see something at this stage.
> What silicon revision do you have on your board? Our i.MX27ads is rev
> 1 which has some incompatibilities to other revs, so maybe this is
> where it breaks. Also, make sure that the SDRAM setup fits for your
> board. For the lowlevel setup you might want to look at Freescale
> provided sources.
>
> Hope that helps
>   Sascha
>
>
I ported Barebox to our MX27 based design a while ago. Our design was 
based on the IP-Cam, and I was able to get the I2C,Ethernet, and the HS 
USB port running. I found the hardest part was getting the PLL config 
work right. I finally just commented it out and let the defaults take 
over. There are some nice ports already and I would suggest looking at 
the systems part of Barebox already. Also start simple, disable 
everything! Even tho the board has all the hardware, don't include it in 
the beginning. I disabled USB,Ethernet,Display,I2C, and it helped a-lot. 
After serial, I would add Ethernet if you are using it. I was simple as 
turning it on. You will need to configure your MAC address. ;-)

As for debugging, I use a cheep olimex arm-usb-ocd (didn't have access 
to the JTAG debuggers at work). Remember you have to setup your ram 
before sending code to the board.  As for a debugger, used gnu tools and 
for the IDE I used insight. I run under Ubuntu and compiled the tools 
from source. (bintools,gcc,gdb, insight)

Hope it helped.
James

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