Thank you for response.
I solved the problem.
After the RFI, MMU begins to work.
I tried to access the phiscal address in serial_hello().
While the address is mapped to another area by BAT.
I think, It's something like the uncertainty theory.
We cannot watch a phenominan precisely, because the action of watching affects
the phenominan.
Any way, I encountered another problem.
I'm porting linux on my MPC755 board.
It is the dump message of xmon after the kernel was crashed during
initialization.
vector: 400 at pc = 20002024, lr = 20002024
msr = 40001032, sp = c0130320 [c0130270]
current = c012e420, pid = 0, comm = swapper
mon>
The point where it happens was in __alloc_bootmem_core.
After the following function.
memset(ret, 0, size);
where
ret = 0xC01D9000
size = 0x200040
Where can I start to debug this.
Thanks in advance.
- Sangmoon Kim -
----- Original Message -----
From: "Babic Stefano" <[EMAIL PROTECTED]>
To: <linuxppc-embedded at lists.linuxppc.org>
Sent: Wednesday, December 19, 2001 1:36 AM
Subject: AW: MPC755 Porting Problem
>
> Hi,
>
> we have already ported linux on our board based on MPC 755. The kernel is set
> at 0xc0000000, as you can see on arch/ppc/Makefile (KERNELLOAD=0xc0000000).
> We did not want to change it, because it is quite a standard value for
> external tools.
> We are using the boot loader in mbx directory (or mbxboot, depending on
> version you are using), so we are using really the head_8260.S file instead
> of head.S.
> From the sources of the loader it seems necessary to load the kernel in high
> memory range (physical address), in any case greater as 0x400000 (which
> address is not important). Then the loader remapped it to 0xc0000000.
> For us it is not a problem to load the kernel at a higher address and in this
> way the loader can correctly start the kernel.
>
> I hope it could be help.
>
> stefano babic
>
> -----Ursprungliche Nachricht-----
> Von: Sangmoon Kim [mailto:dogoil at etinsys.com]
> Gesendet: Samstag, 15. Dezember 2001 07:24
> An: linuxppc-embedded at lists.linuxppc.org
> Betreff: MPC755 Porting Problem
>
>
>
> Hi?
> I'm porting linux for a MPC755 board which I designed,
> and having some trouble with arch/ppc/kernel/head.S
> I load the kernel at phiscal address 0x00000000
> and head.S seams to relocate it to 0xc0000000
> The code is like this
>
> mfmsr r0 /* Inst and data addr translations are disabled */
> ori r0,r0,MSR_DR|MSR_IR /* enable Inst and data addr translation
> */
> mtspr SRR1,r0
> lis r0,start_here at h
> ori r0,r0,start_here at l
> mtspr SRR0,r0
> SYNC
> RFI /* jump to SRR0 */
>
> start_here:
> /* Call setup_cpu for CPU 0 */
> li r3,0 /* data offset */
> li r24,0 /* cpu# */
> bl call_setup_cpu
>
> It is running at base address 0x00000000.
> start_here is at address 0xc000369c.
> And the IBAT0, and DBAT0 is C0001FFE-00000002.
> So after RFI it should go to start_here.
>
> But If I insert some code like 'bl serial_hello',
> which prints hello? to serial console after start_here.
> It never prints a message. It works before the RFI.
>
> Where can I start to debug it?
>
> serial_hello is like this.
>
> void
> serial_hello()
> {
> serial_putc(SCC_A_ADDRESS,'h');
> serial_putc(SCC_A_ADDRESS,'e');
> serial_putc(SCC_A_ADDRESS,'l');
> serial_putc(SCC_A_ADDRESS,'l');
> serial_putc(SCC_A_ADDRESS,'o');
> serial_putc(SCC_A_ADDRESS,'?');
> serial_putc(SCC_A_ADDRESS,'\n');
> serial_putc(SCC_A_ADDRESS,'\r');
> }
> Thanks in advance.
> - Sangmoon Kim -
>
>
>
>
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