PPC405 system slow boot

[Clint Thomas]

Actually, we figured out what was going on. Apparently we left one of
the interrupt lines disconnected from the CPU in the FPGA design. Thanks
for all the help guys, I really do appreciate it.

Clint Thomas

________________________________

From: Clint Thomas 
Sent: Friday, September 01, 2006 6:58 PM
To: linuxppc-embedded at ozlabs.org
Cc: 'Peter Ryser '; Jason Lamb
Subject: RE: PPC405 system slow boot


The xparameters.h file is generated by the Xilinx EDK for our FPGA, so I
don't see how there could be a mismatch. Using Chipscope, we were able
to find that the interrupt controller is triggered on kernel
initialization, but after the kernel has finished loading, the system
moves to a snail's pace at login. 
 
Does Linux use a different set of code to handle the UART, INTC, etc.
after the kernel is loaded? The system appears to work perfectly up
until after the kernel is done loading.

________________________________

From: Peter Ryser [mailto:peter.ryser at xilinx.com] 
Sent: Monday, August 28, 2006 8:45 PM
To: Clint Thomas
Cc: linuxppc-embedded at ozlabs.org
Subject: Re: PPC405 system slow boot


Clint,

check the interrupt sub-system of your design. What you describe
typically happens when the PPC does not get any interrupts from the
UART. It's most likely a mismatch between your hardware and the
xparameters.h.

- Peter


Clint Thomas wrote: 

	Hey guys,
	
	I've run through the loops to try and figure what could be wrong
with this system. The board in question is modeled after the Xilinx
ML300 board. It uses a Xilinx System ACE chip to load a FPGA / Kernel
image from compact flash. Originally, I was trying to use the
CompactFlash as the root file system, but because of issues in either
the design or software, this would only work if SysAce was in polled I/O
mode. To circumvent this, I built my root filesystem into an initrd
image and built a single ELF file with the Kernel and RFS, then strapped
that to the FPGA bit file to make a single FPGA/Kernel/RFS SysAce file.
	
	Upon decompression, the Linux kernel boots quickly and loads all
of the device drivers. However when it gets to the prompt, it starts
slowing down. Output and input to and from the board becomes very very
slow (it displays 2 characters roughly every 20 seconds). Originally I
believed this to be the CPU still polling SystemAce, so I disabled the
Linux System ACE drivers to remove that as a possibility, however after
doing this, the problem still persists, even with the RFS in ram! Has
anybody encountered a similar situation to this before, with possible
insight towards a solution? Thank you for your time.
	 
	Clinton Thomas
	cthomas at soneticom.com
	 
	
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