Add socsesor daemon to handle Ampere SoC sensors in dbus-sensors.

[Thu Nguyen]

On 22/07/2021 23:15, Ed Tanous wrote:
> On Thu, Jul 22, 2021 at 8:56 AM Thu Nguyen
> <thu at amperemail.onmicrosoft.com> wrote:
>> Dear Ed Tanous,
>>
>>
>> As we discussed before about the Ampere CPU daemon in OpenBmc general discord channel. I'm planing to submit the some patches which will add to AmpereSoC daemon source code to dbus-sensors for reviewing. This daemon will handle Ampere Altra SoC sensors. The functions of this daemon are the same as CPUSensor daemon which is handling Xeon CPU sensors.
>>
>> Below is what I will add.
>>
>>      1. Add some files to to Dbus-sensors source:
>>
>>          ./src/AmpereSoCMain.cpp : Match the sensors configurations in entity-manager configuration file with sensor paths in the device driver. And create the SoC sensor dbus objects.
> At this same time, we should rename "CPU sensor" to "Intel CPU" so we
> can easily differentiate.  Ideally your new daemon would also be
> called "AmpereCPU" to keep the naming conventions the same.

I will use AmpereCPU name. And will rename "CPU sensor" to "Intel CPU"

>
>>          ./src/AmpereSoC.cpp : Create the sensor handler and update sensor values to the sensors dbus objects.
>>
>>          ./include/AmpereSoC.hpp : Declare functions and constants.
>>
>>          The structure and the functions of the files are similar the files which create ADCSensor daemon or PSUSensors daemon...
>>
>>      2. Add AmpereSoC daemon which will be named as "xyz.openbmc_project.socsensor.service".
>>
>>          Below is dbus-sensors daemons in our system:
> This list seems disconnected from AmpereSOC.  Was there something you
> were looking for input on there?
>
These are the list of daemons in our system:
~# systemctl | grep sensor
phosphor-virtual-sensor.service                   active running   Virtual sensors
xyz.openbmc_project.adcsensor.service             active running   Adc Sensor
xyz.openbmc_project.fansensor.service             active running   Fan Sensor
xyz.openbmc_project.hwmontempsensor.service       active running   Hwmon Temp Sensor
xyz.openbmc_project.psusensor.service             active running   PSU Sensor
xyz.openbmc_project.socsensor.service             active running   SoC Sensor

>
>
>      3. Add dbus interface to public sensor dbus objects. The name of this interface is "xyz.openbmc_project.SoCSensor".
>
>          Below is some sensors in this dbus interface.
> Neat.

Below are some Ampere SoC sensors in SoCSensor dbus interface.
~# busctl tree xyz.openbmc_project.SoCSensor
`-/xyz
`-/xyz/openbmc_project
     |-/xyz/openbmc_project/inventory
     | `-/xyz/openbmc_project/inventory/system
     |   `-/xyz/openbmc_project/inventory/system/chassis
     |     `-/xyz/openbmc_project/inventory/system/chassis/motherboard
     |       |-/xyz/openbmc_project/inventory/system/chassis/motherboard/CPU_1
     |       `-/xyz/openbmc_project/inventory/system/chassis/motherboard/CPU_2
     `-/xyz/openbmc_project/sensors
     |-/xyz/openbmc_project/sensors/current
     | |-/xyz/openbmc_project/sensors/current/S0_Core_VRD_Curr
     | |-/xyz/openbmc_project/sensors/current/S0_DIMM_VR1_Curr
     | |-/xyz/openbmc_project/sensors/current/S0_DIMM_VR2_Curr
     |-/xyz/openbmc_project/sensors/power
     | |-/xyz/openbmc_project/sensors/power/S0_Core_VRD_Pwr
     | |-/xyz/openbmc_project/sensors/power/S0_DIMM_VR1_Pwr
     | |-/xyz/openbmc_project/sensors/power/S0_DIMM_VR2_Pwr
     |-/xyz/openbmc_project/sensors/temperature
     | |-/xyz/openbmc_project/sensors/temperature/S0_Core_VRD_Temp
     | |-/xyz/openbmc_project/sensors/temperature/S0_DIMM_CH4_Temp
     | |-/xyz/openbmc_project/sensors/temperature/S0_DIMM_VRD_Temp
     `-/xyz/openbmc_project/sensors/voltage
         |-/xyz/openbmc_project/sensors/voltage/S0_CPU_VCORE
         |-/xyz/openbmc_project/sensors/voltage/S0_DIMM_VR1_Volt
         |-/xyz/openbmc_project/sensors/voltage/S0_DIMM_VR2_Volt

>>
>>
>>      4. The causes of this adding are:
>>          + The Ampere SoCs and their interfaces are quite complicated to use the current daemons.
> Considering that ampere CPUs support their own disparate OOB
> interface, I suspect it's ideal that they would be separated out into
> their own daemon.

Currently, Our openbmc uses I2C and GPIO to communicate/monitor our CPU thru SCP to get sensors, errors and events.
The openbmc is depend on SCP.

>
>>          + We can't use CPUSensor daemon which is specific for Intel Xeon. We use I2C interface to access the SoC sensors which Intel Xeon using PCIE.
> This is fine, and what I would've expected.  CPU sensor is fairly
> specific to PECI today.
>
>>          + Our SoC hwmon drivers are different with the other hwmon drivers in linux kernel. We are using one MDF driver name ac01-smpro, it have three sub drivers ac01-hwmon which report the temperature, the consumed power, current and voltage of components in SOC.
>>          + In the near future, We append AmpereSoC daemon to monitor SoC RAS and SoC events as you suggested.
>>
>>      Please let me know if you have any comments about this plan.
>
> I'm looking forward to the patches.  I don't see any concerns, as
> everything above looks like you're following the existing interfaces.
>
>>
>> Thanks.
>>
>> Thu.
>>
>>
>>
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