linux-kernel - Re: [PATCH v4 0/9] misc: Add AMD side band interface(SBI) functionality

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Message-ID: <9b0cc2c4-44d3-3038-54b3-d4793b879820@amd.com>
Date: Fri, 20 Sep 2024 12:15:37 +0530
From: "Gupta, Akshay" <Akshay.Gupta@....com>
To: linux-hwmon@...r.kernel.org, linux-kernel@...r.kernel.org,
 gregkh@...uxfoundation.org, arnd@...db.de
Cc: linux@...ck-us.net, naveenkrishna.chatradhi@....com
Subject: Re: [PATCH v4 0/9] misc: Add AMD side band interface(SBI)
 functionality


On 9/12/2024 12:38 PM, Akshay Gupta wrote:
> AMD's Advanced Platform Management Link (APML) interface provides system
> management functionality accessed by the baseboard management controller (BMC).
> sbrmi driver under hwmon subsystem, which is probed as an i2c driver and
> reports power using APML specified protocol.
> However, APML interface defines few other protocols to support
> full system management functionality out-of-band.
> Out-of-band management is term used for BMC talking to system management unit
> (IP in the processor). AMD's documentation called this link as side band interface.
>
> This patchset is an attempt to add all APML core functionality in one place
> and provide hwmon and user space interface
> 1. [Patch 1] Move the i2c client probe, hwmon sensors and sbrmi core functionality
>     from drivers/hwmon to drivers/misc/
> 2. [Patch 2] Convert i2c to regmap which provides multiple benefits
>     over direct smbus APIs.
>      a. i2c/i3c support and
>      b. 1 byte/2 byte RMI register size addressing
> 3. [Patch 3] Optimize wait condition with regmap API regmap_read_poll_timeout as per
>     suggestion from Arnd
> 4. [Patch 4, 5] Register a misc device which provides
>      a. An ioctl interface through node /dev/sbrmiX
>      b. Register sets is common across APML protocols. IOCTL is providing
>         synchronization among protocols as transactions may create
>         race condition.
> 5. [Subsequent patches 6, 7 and 8] add support for AMD custom protocols
>      a. CPUID
>      b. MCAMSR
>      c. Register xfer
> 6. [Patch 9] AMD side band description document
>
> Open-sourced and widely used https://github.com/amd/esmi_oob_library
> will continue to provide user-space programmable API.
>
> Akshay Gupta (9):
>    hwmon/misc: amd-sbi: Move core sbrmi from hwmon to misc
>    misc: amd-sbi: Use regmap subsystem
>    misc: amd-sbi: Optimize the wait condition for mailbox command
>      completion
>    misc: amd-sbi: Add support for AMD_SBI IOCTL
>    misc: amd-sbi: Add support for mailbox error codes
>    misc: amd-sbi: Add support for CPUID protocol
>    misc: amd-sbi: Add support for MCA register protocol
>    misc: amd-sbi: Add supoort for register xfer
>    misc: amd-sbi: Add document for AMD SB IOCTL description

Hi Greg, Arnd,

You have previously reviewed v3 of patch set and I have addressed the 
review comments in v4.

Can you please take review v4 patch set?

Thank you.

>
>   Documentation/misc-devices/amd-sbi.rst        |  84 ++++
>   Documentation/misc-devices/index.rst          |   1 +
>   .../userspace-api/ioctl/ioctl-number.rst      |   2 +
>   drivers/hwmon/Kconfig                         |  10 -
>   drivers/hwmon/sbrmi.c                         | 357 --------------
>   drivers/misc/Kconfig                          |   1 +
>   drivers/misc/Makefile                         |   1 +
>   drivers/misc/amd-sbi/Kconfig                  |   9 +
>   drivers/misc/amd-sbi/Makefile                 |   3 +
>   drivers/misc/amd-sbi/rmi-core.c               | 452 ++++++++++++++++++
>   drivers/misc/amd-sbi/rmi-core.h               |  67 +++
>   drivers/misc/amd-sbi/rmi-hwmon.c              | 122 +++++
>   drivers/misc/amd-sbi/rmi-i2c.c                | 135 ++++++
>   include/uapi/misc/amd-apml.h                  |  97 ++++
>   14 files changed, 974 insertions(+), 367 deletions(-)
>   create mode 100644 Documentation/misc-devices/amd-sbi.rst
>   delete mode 100644 drivers/hwmon/sbrmi.c
>   create mode 100644 drivers/misc/amd-sbi/Kconfig
>   create mode 100644 drivers/misc/amd-sbi/Makefile
>   create mode 100644 drivers/misc/amd-sbi/rmi-core.c
>   create mode 100644 drivers/misc/amd-sbi/rmi-core.h
>   create mode 100644 drivers/misc/amd-sbi/rmi-hwmon.c
>   create mode 100644 drivers/misc/amd-sbi/rmi-i2c.c
>   create mode 100644 include/uapi/misc/amd-apml.h
>