MPC8240 PTE setup
rmorin at miranda.com
Tue Apr 23 04:07:46 EST 2002
I am new to embedded Linux but I have more than 10 years experience
in embedded systems on many different processors and real-time
I have based my work on the Linux kernel 2.5.8 and the ZX4500 platform
(plus my modification). My goal is to move from pSOS to Linux and for the
moment I am using the pSOS bootloader (PPCBOOT on its way) to load
the linux kernel.
I have a problem with the MMU (MPC8240+CPLD+serial
port+DiskOnChip on PortX). The boot process is looping in
openpic_safe_writefield() and I can see with my BDI2000 that the
MMU is not translating correctly virtual addresses to physical
addresses. I made a patch to use a BAT instead of PTE but
this cause only to move the problem further upstream
(unable to run /busybox correctly).
I have check the parameter passed with ioremap() and it's
ok. With the BDI2000, I get this with the phys command:
phys 0xfdfd0000 (virtual address returned by ioremap)
PHYS = 0xfffff000 END = 0xffffffff
PHYS 0xfdf40000 END = 0xfdffffff
Here is a screenshot (this is a pSOS boot sequence):
Standard output device initialized...
System clock initialized...
SYSTEM START @ 09:52:18 22/04/2002 (usec tick)
DiskOnChip has a capacity of 32 MB
Initializing User Accounts, this may take a while...
Initializing FTP Server Daemon...
15.0/mxz/index : 200b - prepc error value
No startup table - cannot initialize revision control.
Cannot open system files -- trying TFTP instead.
Remote file: zImage.img, IP: 10.64.21.18
TFTP download completed.
Transfering control to the downloaded code.
(here it is)
loaded at: 00100000 001B0BCC
relocated to: 00800000 008B0BCC
zimage at: 00805980 0088DBE4
initrd at: 0088E000 008A69BF
avail ram: 00400000 00800000
Linux/PPC load: console=ttyS0,19200 root=/dev/ram0 init=/busybox lash
Now booting the kernel
Miranda Media Network
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