[coreboot] northbridge Intel 82846 ==>southbridge Intel 82801GX (ICH7) ==>IT8718 which is UART (I/0)

[Riko Ho]

I have no idea as well, I'm a beginner on coreboot stuff..you know 
better than me...

What I'm thinking, I need to find a way for initializing northbridge 
Intel 82946 ==>southbridge Intel 82801GX (ICH7) ==>IT8718 which is UART 
(I/0) since it has GPIO as well...
I got no idea on how to initialize northbridge yet....

what do you reckon ? can CPU talk directly to IT8718F in this case ? or 
it needs NB and SB ?
Is any more documentations for Intel 82946 ? or that's the only one we 
can obtain ?

It doesn't matter if we can not find it, I want to learn, it's very good 
if we can solve it...but it's not, I have nothing to loose...

On 8/11/2016 7:25 AM, Idwer Vollering wrote:
> I don't know, what do you think?
>
> 2016-11-08 0:07 GMT+01:00 Riko Ho :
> > On 7/11/2016 10:55 AM, Idwer Vollering wrote:
> >
> > /
> >
> > 2016-11-07 2:59 GMT+01:00 Riko Ho :
> >
> > Next line you're talking about :
> >          |   f000:0f10    66becc8100e0 mov esi, 0xe00081cc
> >          |   f000:0f16    67268b06     mov ax, [es:esi]
> >          |   f000:0f1a    0d0010       or ax, 0x1000
> >
> > ======
> >  From what I recall is nico_h on IRC hinted that the PCIe bus must be
> >   up in order to be able to use the UART.
> >   There could be code for this that touches PCIEXBAR around these lines:
> >     |||||||   f000:0f10      66becc8100e0   mov esi, 0xe00081cc
> >     |||||||   f000:0f16      67268b06       mov ax, word es:[esi]
> >     |||||||   f000:0f1a      0d0010         or ax, 0x1000
> >
> > Since this writes to ax, the C code could look like this:
> >   MCHBAR16(0xe00081cc) |=0x1000;
> >   This would end up in romstage.c
> > ======
> >
> > in which function I put that MCHBAR16(0xe00081cc) |=0x1000; on romstage.c ?
> >
> > No idea, it might belong in src/northbridge/intel/i945/raminit.c
> > instead. The C macro, MCHBAR16(), I mentioned was an example and won't
> > be useful for PCIEXBAR.
> >
> > So what should we do for getting the correct PCIEXBAR and making UART
> > running ?
> >
> > =====
> > I suggest that you read at least chapter "5 Host Bridge/DRAM
> > Controller Registers (Device 0, Function 0) " starting on page 75.
> > =====
> >
> > Ok, I will do that, but I'm sure I have a lot of questions in relation
> > with the reversed code and romstage.c and this chapter 5.