[coreboot-gerrit] [M] Change in coreboot[main]: soc/intel/alderlake: Add function to force disable memory channels

[Kapil Porwal (Code Review)]

Attention is currently required from: Angel Pons, Christian Walter, Dinesh Gehlot, Eric Lai, Jamie Chen, Jayvik Desai, Jeremy Soller, Lean Sheng Tan, Michał Kopeć, Michał Żygowski, Nick Vaccaro, Paul Menzel, Piotr Król, Sean Rhodes, Subrata Banik, Tim Crawford.

Hello Angel Pons, Christian Walter, Dinesh Gehlot, Eric Lai, Jamie Chen, Jayvik Desai, Jeremy Soller, Lean Sheng Tan, Michał Kopeć, Michał Żygowski, Nick Vaccaro, Piotr Król, Sean Rhodes, Subrata Banik, Tim Crawford, build bot (Jenkins),

I'd like you to reexamine a change. Please visit

https://review.coreboot.org/c/coreboot/+/85529?usp=email

to look at the new patch set (#5).

The following approvals got outdated and were removed:
Verified+1 by build bot (Jenkins)

Change subject: soc/intel/alderlake: Add function to force disable memory channels
......................................................................

soc/intel/alderlake: Add function to force disable memory channels

Add a function `mem_init_override_channel_mask` to disable memory
channels based on given bitmap where each bit represents a memory
channel. A set bit will disable corresponding memory channel. Variants
can override this bitmap by selecting `ENFORCE_MEM_CHANNEL_DISABLE` and
implementing `mb_fill_override_channel_mask` to return the bitmap.

BUG=b:379311559
TEST=Make sure that channel mask is applied correctly.

Lotso without any channel mask:
```
lotso-rev0 ~ # dmidecode -t 17 | grep -E "(Locator: C|Size)"
        Size: 2 GB
        Locator: Channel-0-DIMM-0
        Size: 2 GB
        Locator: Channel-1-DIMM-0
        Size: 2 GB
        Locator: Channel-2-DIMM-0
        Size: 2 GB
        Locator: Channel-3-DIMM-0
        Size: 2 GB
        Locator: Channel-0-DIMM-0
        Size: 2 GB
        Locator: Channel-1-DIMM-0
        Size: 2 GB
        Locator: Channel-2-DIMM-0
        Size: 2 GB
        Locator: Channel-3-DIMM-0

lotso-rev0 ~ # dmidecode -t 17 | grep Size | wc -l
8
```

Lotso with channel 2 & 3 masked:
```
lotso-rev0 ~ # dmidecode -t 17 | grep -E "(Locator: C|Size)"
        Size: 2 GB
        Locator: Channel-0-DIMM-0
        Size: 2 GB
        Locator: Channel-1-DIMM-0
        Size: 2 GB
        Locator: Channel-0-DIMM-0
        Size: 2 GB
        Locator: Channel-1-DIMM-0

lotso-rev0 ~ # dmidecode -t 17 | grep Size | wc -l
4
```

Change-Id: Ibfeca4509cb3d88bc1bac2ac2d480e665d895bc5
Signed-off-by: Kapil Porwal 
---
M src/soc/intel/alderlake/Kconfig
M src/soc/intel/alderlake/include/soc/meminit.h
M src/soc/intel/alderlake/meminit.c
3 files changed, 54 insertions(+), 0 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/29/85529/5