Hi,

On Thu, Mar 12, 2020 at 11:07 AM Michal Zygowski
<michal.zygowski@3mdeb.com> wrote:
>
> Hi,
>
> it may also be a Cedarview chipset. According to my knowledge there is
> no support for Cedarview chipset in coreboot. However coreboot has
> slightly older (1 year older) chipset support - Pineview.

Pineview is very different, though. Memory initialization for Pineview
resembles that of Eaglelake (src/northbridge/intel/x4x). Although it
only has one memory channel, the registers in MCHBAR are very similar.

On the other hand, Cedarview's internal architecture differs radically
from Pineview, and it is actually more like Bay Trail. Both use the
IOSF architecture, and memory is initialized by interacting with
various "units" inside the chip.

About the southbridge, I don't know if Cedarview can use NM10 (found
on Pineview) or if it must use an EG20T PCH:
https://ark.intel.com/content/www/us/en/ark/products/52501/intel-platform-controller-hub-eg20t.html

> My experience is very little when it comes to older chipsets, but
> judging by how sanydbridge and ivybridge works, pineview and cedarview
> should have most thing in common. That said, i would try to go out from
> pineview northbridge in coreboot. The next question is which southbirdge
> to choose. There are two mainboards based on pineview. Most likely you
> would have to select:
>
>     select CPU_INTEL_SOCKET_FCBGA559
>     select NORTHBRIDGE_INTEL_PINEVIEW
>     select SOUTHBRIDGE_INTEL_I82801GX
>
> in your mainboard Kconfig. The CPU socket also matches according to
> Intel ARK about N2600
>
> https://ark.intel.com/content/www/us/en/ark/products/58916/intel-atom-processor-n2600-1m-cache-1-6-ghz.html

Note that, even though the LGA775 socket was used for many different
CPU generations, not every LGA775 mainboard can take any LGA775 CPU.

> The initialization for that particular silicon is native so no FSP
> required. Since it may be hard to debug, I advise to get a USB debug
> dongle and enable it in coreboot menuconfig. But before that, find out
> which USB port on this netbook is connected to EHCI debug port.
> Typically it is the first port on the root hub. You can find it out
> using lspci and lsusb in Linux (by connecting a USB-UART dongle for
> example to the investigated port). The dongles supported by coreboot
> are: FTDI232H/FTDI2232H, or you can use BeagleBone board.

There's also `util/find_usbdebug` in coreboot.

> Regards,
>
> --
> Michał Żygowski
> Firmware Engineer
> https://3mdeb.com | @3mdeb_com
>
> On 12.03.2020 06:06, Benjamin Doron wrote:
> > Hi,
> > The Intel FSP (Firmware Support Package) is a required part of chipset initialisation. I can't find one for Cedar View, (github.com/IntelFsp/FSP) the family your CPU, an Atom N2600, is a part of.

There is an old FSP around: QueensBayFspBinPkg. However, it will not
work with current coreboot, as FSP 1.0 support had to be dropped.

> > Somebody else should confirm (I don't know your platform well), but it seems impossible about this. Sorry.

The first MinnowBoard uses a Cedarview chip. There is some ancient EFI
firmware around:
https://github.com/RafaelRMachado/MinnowBoard/tree/master

There might be something better thank stinky binaries somewhere, but I
don't know if it's still around after eight years...

> > _______________________________________________
> > coreboot mailing list -- coreboot@coreboot.org
> > To unsubscribe send an email to coreboot-leave@coreboot.org
>
> _______________________________________________
> coreboot mailing list -- coreboot@coreboot.org
> To unsubscribe send an email to coreboot-leave@coreboot.org

Best regards,

Angel Pons
_______________________________________________
coreboot mailing list -- coreboot@coreboot.org
To unsubscribe send an email to coreboot-leave@coreboot.org