Change in coreboot[master]: soc/amd/{common,cezanne}: Add uPEP device

[Raul Rangel (Code Review)]

Attention is currently required from: Jason Glenesk, Raul Rangel, Marshall Dawson, Felix Held.
Hello build bot (Jenkins), Jason Glenesk, Furquan Shaikh, Marshall Dawson, Felix Held,

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

https://review.coreboot.org/c/coreboot/+/52445

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

Change subject: soc/amd/{common,cezanne}: Add uPEP device
......................................................................

soc/amd/{common,cezanne}: Add uPEP device

The uPEP device is required to support S0i3. The device has been written
in ASL to make it easier to read and maintain. The device constraints
are purely informational. We use a dummy constraint like the Intel
platforms to keep both linux and Windows functional.

In order for this device to be used by the linux kernel the
ACPI_FADT_LOW_PWR_IDLE_S0 flag must be set. So including it
unconditionally doesn't cause any problems.

The AMD Modern Standby BIOS Implementation Guide defines two UUIDs,
one for getting the device constraints, and one for handling
notifications. This differs from the Intel specification and the linux
driver implementation. For this reason I haven't implemented any of the
notification callbacks yet.

BUG=b:178728116
TEST=Boot OS and verify _DSM is called:
[    0.226701] lps0_device_attach: ACPI: _SB_.PEP_: _DSM function mask: 0x3
[    0.226722] lpi_device_get_constraints_amd: ACPI: _SB_.PEP_: _DSM function 1 eval successful
[    0.226723] lpi_device_get_constraints_amd: ACPI: _SB_.PEP_: LPI: constraints list begin:
[    0.226724] lpi_device_get_constraints_amd: ACPI: _SB_.PEP_: LPI: constraints list end

Signed-off-by: Raul E Rangel 
Change-Id: I2deef47eabe702efe1a0f3747c9f27bcec37464b
---
M src/soc/amd/cezanne/acpi/soc.asl
A src/soc/amd/common/acpi/upep.asl
2 files changed, 133 insertions(+), 0 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/45/52445/5