Embedded PowerPC750 problem: Kernel slow response from console

Embedded PowerPC750 problem: Kernel slow response from console

[Rob Grimm]

Hello All,
    We are working on porting linux to an embedded platform based off of the
PowerPC750.
We are using Linux-2.2.13 configured for serial port console (there is a
standard 16550 onboard).  So far, the kernel
appears to boot fine (with networking disabled).  After we get the message
about freeing kernel
memory, it takes about 10 seconds for the bash# prompt to appear.  Once we
get to this
point, it seems like the kernel runs extremely slow.  When we type a letter,
it takes about 10
seconds for the letter to show up on the console ouput.
    I believe it has something to do with the interrupt controller (which we
do not have setup correctly yet).
I have tried both disabling and enabling external interrupts, and get the
same results.  Has anyone
experienced similar problems?  We started off with the kernel configured for
a Prep system
(we later found out that our system is not much like the prep system), and
went
from there.  How does the kernel handle the serial console input if the
interrupt is disabled?  It appears
that the kernel is running fine, I can do an "ls" and "cd" with no problems,
it just takes a long time
to see any results.  Thanks in advance for any help.

Regards,
Rob Grimm

-----------------------------
Rob Grimm
Real-Time Digital
rgrimm@rtdsp.com
732-681-5700 x13
-----------------------------


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Re: Embedded PowerPC750 problem: Kernel slow response from console

[Gabriel Paubert]

On Mon, 6 Mar 2000, Rob Grimm wrote:

>
> Hello All,
>     We are working on porting linux to an embedded platform based off of the
> PowerPC750.
> We are using Linux-2.2.13 configured for serial port console (there is a
> standard 16550 onboard).  So far, the kernel
> appears to boot fine (with networking disabled).  After we get the message
> about freeing kernel
> memory, it takes about 10 seconds for the bash# prompt to appear.  Once we
> get to this
> point, it seems like the kernel runs extremely slow.  When we type a letter,
> it takes about 10
> seconds for the letter to show up on the console ouput.

It happened to me in some versions of the kernel (2.3.45) since I use a
serial console in most configurations, the problem was indeed the
interrupt controller which was not initialized. It depends on your HW
however, in my case it was a typo which prevented using the 8259 when
cascaded with an OpenPIC. I mentioned it on the linuxppc-dev list and Cort
corrected the typo. It actually appeared in official 2.3.47 or so (I don't
remember exactly since I'm still at 2.3.45, I'm going to check soon
if 2.3.49 wants to work again with nfsroot).

>     I believe it has something to do with the interrupt controller (which we
> do not have setup correctly yet).

Which kind of interrupt controller do you have ?

> I have tried both disabling and enabling external interrupts, and get the
> same results.  Has anyone
> experienced similar problems?  We started off with the kernel configured for
> a Prep system
> (we later found out that our system is not much like the prep system), and
> went
> from there.  How does the kernel handle the serial console input if the
> interrupt is disabled?  It appears

I actually use the CHRP/PreP/PMAC option, and the bootloader reprograms
the host bridge (Motorola ravn or Hawk) from PreP to CHRP like mapping.

	Gabriel.


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Cross-compiling Bash

[Rob Grimm]

All,
    I apologize if this topic has come up before, I checked the archives but
could
not find the answer I'm looking for.

     I have successfully setup a cross-compiler
on an x86 computer, to build code for our embedded PowerPC750 platform.  I
have been able compile the kernel, create a ramdisk, and the kernel boots
fine.
I have been using a small filesystem I downloaded for the mbx board, and can
run the included bash.   My question is, has anyone successfully
cross-compiled
bash (any version, or any GNU software package for that matter)?  Whenever
I run configure (I set all the command line options, like
CC=mycompilername --target=
blah), it says something like can not run test when using cross - compiling.
I get the same results, no matter which GNU package I try to compile (ie
shell-utils).
I have also tried running configure with no options, and then manually
editing
the makefiles so it uses my cross-compiler, this does not work either.
Here is the stuff I am using for my cross-compiler (which has all been built
successfully):
           binutils-2.9.1.0.19a
           egcs-1.1.2
           glibc-2.1.2
           glibc-crypt-2.0.111
           glibc-linuxthreads-2.1.2

Does anyone have any suggestions?  I'm trying to avoid going out and buying
a powermac.  How do others handle this problem, when developing code
on a non-powerpc platform?

    Also, I have tried running pre-built binaries, which I got from
ftp.linuxppc.orq, with
no success.  I downloaded pre-built libs, bash..., and all I get is "init"
on the console
after the kernel boots.  It then hangs up.

Thanks in advance.

Regards,
Rob Grimm

-----------------------------
Rob Grimm
Real-Time Digital
rgrimm@rtdsp.com
-----------------------------


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Re: Cross-compiling Bash

[Gilbert Coville]

At 2:11 PM -0800 3/10/00, Rob Grimm wrote:

>Does anyone have any suggestions?  I'm trying to avoid going out and buying
>a powermac.  How do others handle this problem, when developing code
>on a non-powerpc platform?

Cross compiling bash is pretty weird.

Check out how we did it in the 8xx version of our Cross Development Kit.
The recipe will be the same for your 750 -- just point it to your 750 cross
tools.  The recipe is in the %build portion of the SPEC file in the SRPM
for bash:
ftp://ftp.mvista.com/pub/CDK/1.0/ppc_8xx/SRPMS/hhl-ppc_8xx-bash-2.03-4.src.rpm

Also, we'll have a 750-based version of our CDK out in a few days, if
you're willing to wait.

Gilbert

--
Gilbert Coville			MontaVista Software Inc.
gilbert@mvista.com		+1 408-328-9208


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