Help! mpc8247 porting kernel 2.6.25 problem.

Scott Wood scottwood at
Wed Apr 23 03:19:12 EST 2008

On Tue, Apr 22, 2008 at 01:10:54PM +0800, 张世乐 wrote:
> Thank you, Doctor Scott. I'm very grateful to you for you kindly help.
> I'll try the way you suggested soon.
> And, my code for light the led run as follows:
> void set_led_a_red(void)
> {
> 	/*PDIRC: 0xfc010d40*/
> 	/*PPARC: 0xfc010d44*/
> 	/*PODRC: 0xfc010d4c*/
> 	/*PDATC: 0xfc010d50*/
> 	*((unsigned long *)(0xfb010d40)) |= 0x000000d4;
> 	*((unsigned long *)(0xfb010d44)) &= ~0x000000d4;
> 	*((unsigned long *)(0xfb010d4c)) &= ~0x000000d4;
> 	*((unsigned long *)(0xfb010d50)) |= 0x00000004;
> 	*((unsigned long *)(0xfb010d50)) &= ~0x00000010;
> }

Use out_be32(), and put a dcbf at the end.  If the dcbf doesn't help, try
not accessing any I/O until after the MMU is set up, and use a
cache-inhibited BAT mapping.  It's usually not between enabling caches
and enabling the MMU that something goes wrong, but it is a rather
annoying debug barrier.

As for early debug output not working, another possibility besides the
descriptor address is that ppc_md.probe is failing, or that your board
file doesn't set ppc_md.progress to udbg_progress.


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