[U-Boot-Users] custom 8245 board & exceptions

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[U-Boot-Users] custom 8245 board & exceptions

"Callebaut, Benoît"
Hello,
This is my first project with a PowerPC.
Our board is loosely based on the Sandpoint 8245 Unity board. The main
difference is that it contains also a DSP and FPGA. The PowerPC related part
is only composed of the MPC8245 running as PCI agent , 16MB of SDRAM, 2
Flash ("primary" of 512KB and second one of 8MB) and the PCI bus (no serial
port->no console)
I can Flash PPCBOOT with the BDI and use he SDRAM.
I modified the putc and puts functions to write in a circular buffer located
in RAM.
The problem is that that doesn't always work. I receive a "data storage
interrupt" coming from  the function initdram.
Note that the circular buffer is initialized just after initdram and that
the position of the buffer and its data structure is hard wired in the
program.

I receive sometime a TLB miss exception

What can be the cause of that since I didn't changed anything in the memory
management code ?

I received before also a decrementer interrupt and I disabled the bit for
it. I don't understand clearly the usefulness of this. Does it work like a
watchdog ?

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Benoit Callebaut
Software Development Engineer
Barco | Control Rooms
Noordlaan 5, 8520 Kuurne, Belgium
 
Tel +32(0)56 36 84 28
Fax +32(0)56 36 86 05

mailto:benoit.callebaut at barco.com
http://www.barcocontrolrooms.com

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[U-Boot-Users] custom 8245 board & exceptions

Wolfgang Denk
Hello,

in message <81A66F72DCACD511B0600002A551BFCB4E9CA3 at kuumex05.barco.com> you wrote:
>
> Our board is loosely based on the Sandpoint 8245 Unity board. The main
> difference is that it contains also a DSP and FPGA. The PowerPC related part
> is only composed of the MPC8245 running as PCI agent , 16MB of SDRAM, 2
> Flash ("primary" of 512KB and second one of 8MB) and the PCI bus (no serial
> port->no console)
> I can Flash PPCBOOT with the BDI and use he SDRAM.
> I modified the putc and puts functions to write in a circular buffer located
> in RAM.

This is NOT a good idea. Console I/O is iused a long time before  the
RAM gets initialized, so you are provoking undefined behaviour.

> The problem is that that doesn't always work. I receive a "data storage
> interrupt" coming from  the function initdram.
> Note that the circular buffer is initialized just after initdram and that
> the position of the buffer and its data structure is hard wired in the
> program.

But console I/O is used long before that!

> I received before also a decrementer interrupt and I disabled the bit for
> it. I don't understand clearly the usefulness of this. Does it work like a
> watchdog ?

I suggest you get yourself a BDI2000, which allows for good debugging
features, but also for a remote console feature which might be _very_
handy in your situation.

Ummm... and think about some form of  punishment  for  the  guys  who
designed  your  hardware.  A  board  without  a  serial  port is very
programmer-unfriendly.

Best regards,

Wolfgang Denk

--
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88  Email: wd at denx.de
See us @ electronica 2002 in Munich, Nov 12-15, Hall A3, Booth A3.325



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[U-Boot-Users] custom 8245 board & exceptions

Holger Schurig
> I suggest you get yourself a BDI2000, which allows for good debugging
> features, but also for a remote console feature which might be _very_
> handy in your situation.

How does remote console function with a BDI2000 ?

What Do I have to compile into u-boot?   Will I see the output of the printf's
when I do a "telnet bdi" ?


I only knew the other way around, that I can connect a serial cable from the
bdi2000 to a serial port of my target, allowing me a "telnet" into the serial
port of the target.




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[U-Boot-Users] custom 8245 board & exceptions

Wolfgang Denk
In message <200211051340.54645.h.schurig at mn-logistik.de> you wrote:
>
> I only knew the other way around, that I can connect a serial cable from the
> bdi2000 to a serial port of my target, allowing me a "telnet" into the serial

Arrgh... sorrry, I was wrong. So far, I too used  the  "SIO"  feature
which  connects  a  telnet  session  the  the  BID's  RS232  port.  I
remembered that there was another feature for  "virtual  I/O"  ("VIO"
parameter) which only needs the JTAG connection to the target, but my
memroy was wrong how this is implemented (you must still have an UART
on  the board, with RxD and TxD routed to sperecial spare pins on the
COP header).

Please forget my suggestion....

Best regards,

Wolfgang Denk

--
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88  Email: wd at denx.de
See us @ electronica 2002 in Munich, Nov 12-15, Hall A3, Booth A3.325