[M] Change in coreboot[master]: soc/amd/common/block/acpi/cpu_power_state: add get_cstate_info helper

[Felix Held (Code Review)]

Attention is currently required from: Jason Glenesk, Raul Rangel, Matt DeVillier, Fred Reitberger.

Hello build bot (Jenkins), Jason Glenesk, Raul Rangel, Matt DeVillier, Fred Reitberger,

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

https://review.coreboot.org/c/coreboot/+/73428

to look at the new patch set (#4).

Change subject: soc/amd/common/block/acpi/cpu_power_state: add get_cstate_info helper
......................................................................

soc/amd/common/block/acpi/cpu_power_state: add get_cstate_info helper

Introduce the get_cstate_info helper function that populates the caller-
provided cstate_values array with the data returned by the SoC-specific
get_cstate_config_data function. From the array get_cstate_config_data
returns, only the ctype, latency and power fields are used, so the rest
can be left uninitialized. Those 3 fields are compile-time constants.
For each entry, write_cstate_entry will generate the corresponding
resource information from the given data. In the C1 case where ctype is
1, the state is entered via a MWAIT instruction, while the higher C
states are entered by doing an IO read from a specific IO address. This
IO address is x - 1 bytes into the IO region starting at
MSR_CSTATE_ADDRESS for the Cx state. So for example C2 is entered by
reading from the C state IO base address + 1. This resource information
is generated during runtime, since the contents of MSR_CSTATE_ADDRESS
aren't necessarily known at compile-time.

MAX_CSTATE_COUNT is introduced so that the caller can allocate and pass
a buffer with space for the maximum number of C state entries. This
maximum number corresponds to the number of IO addresses the CPU traps
beginning from MSR_CSTATE_ADDRESS. In practice, it's unlikely that more
than 3 or maybe 4 C states will be available though.

Signed-off-by: Felix Held 
Change-Id: I2c36c1d604ced349c609882b9d9fe84d5f726a8d
---
M src/soc/amd/common/block/acpi/Kconfig
M src/soc/amd/common/block/acpi/Makefile.inc
A src/soc/amd/common/block/acpi/cpu_power_state.c
M src/soc/amd/common/block/include/amdblocks/cpu.h
4 files changed, 108 insertions(+), 0 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/28/73428/4