Re: [PATCH v8 00/10] misc: Move AMD side band interface(SBI) functionality

Arnd Bergmann
2025-04-11T13:52:43Z

On Fri, Apr 11, 2025, at 15:31, Akshay Gupta wrote:
> At present, sbrmi driver under hwmon subsystem, is probed as an i2c
> driver,
> fetches data using APML specified protocol and reports through hwmon
> power sensor.
>
> AMD provides additional information using custom protocols, which cannot be
> enumerated as hwmon sensors. Hence, move the existing functionality from hwmon/
> to misc/ and add support for following custom protocols
> - read Processor feature capabilities and configuration information
> through side band.
> - read Machine Check Architecture(MCA) registers over sideband.
> The information is accessed for range of MCA registers by passing
> register address and thread ID to the protocol.
>
> NOTE: AMD defines Advanced Platform Management Link (APML) interface
> which provides
> system management functionality access to the baseboard management
> controller (BMC).

I think this addresses all my comments, thanks for the update.

> Open-sourced and widely used [1]_ will continue to provide user-space
> programmable API.
>
> .. [1] https://github.com/amd/esmi_oob_library

I'm still a little uneasy about the low-level mailbox interface
being exposed in a character device, but assuming that everyone
else is fine with having that in principle, I think the way the
interface is structured in this version is good enough.

Arnd