Hi,
Please see below...


-----Original Message-----
From: Charles M. Hannum [mailto:abuse@spamalicious.com]=20
Sent: Friday, March 26, 2004 2:39 AM
To: Lin, Colin(=AAL=AB=D8=A6w IAC)
Cc: port-arm@NetBSD.org
Subject: Re: How to port NetBSD to a new platform with OMAP 1610

> On Thursday 25 March 2004 09:47 am, Lin.Colin@iac.com.tw wrote:
> > I am currently working on porting NetBSD to OMAP 1610.
> >
> > Not familiar with NetBSD before, I had paid a lot of time on =
surveying it.
> >
> > I found that NetBSD already supports ARM9 core (ARM920T), and OMAP =
1610
> > belongs to ARM926.

> I've ported NetBSD to the DM310, which is similar.  (Unfortunately I =
can't=20
> release that code.)

> > Many questions needed to be solved:
>>
> > 1.       What=A1=A6s difference between ARM920T and ARM926? Does the =
kernel of
> > ARM920T run well on ARM926 without any modifying?

> There is very little difference in the ARM core itself.  However, =
everything=20
> *else* is different.  In particular, you will have to implement custom =

> interrupt routing for the OMAP processor.  (I think it's different on =
each=20
> one.)

What does "everything" mean? Does it mean "device drivers", and =
interrupts for device drivers are therefore different?


> > 2.       Dram and NOR Flash have been set up in U-BOOT. Need the =
kernel do
> > it again in the beginning?

> No; if you've already set up the clocking and initialized the RAM, you =
don't=20
> need to do it again -- though it doesn't hurt.

That's great for me.

> > 3.       =A1=A7KERNEL_BASE_PHYS=A1=A8 is used to set up the load =
place of the kernel,
> > and what=A1=A6s =A1=A7KERNEL_BASE_VIRT=A1=A8?

> The kernel maps itself (and is therefore linked) at a different =
address that=20
> the physical address it's loaded at.

Why we want to map kernel to a higher virtual address?
Is it that lower virtual address is used by applications?
Can I change this virtual address as me pleases?


Thanks and regards
Colin