[PATCH v2 02/10] docs: ABI: sysfs-bus-event_source-devices-hv_gpci: Document processor_bus_topology sysfs interface file

[kajoljain]

Thanks Randy for the review comments, I will do these updates
for all documentation patches in my next version of patchset.

Thanks,
Kajol Jain

On 7/12/23 02:22, Randy Dunlap wrote:
> Hi--
> 
> On 7/10/23 02:27, Kajol Jain wrote:
>> Add details of the new hv-gpci interface file called
>> "processor_bus_topology" in the ABI documentation.
>>
>> Signed-off-by: Kajol Jain <kjain at linux.ibm.com>
>> ---
>>  .../sysfs-bus-event_source-devices-hv_gpci    | 32 +++++++++++++++++++
>>  1 file changed, 32 insertions(+)
>>
>> diff --git a/Documentation/ABI/testing/sysfs-bus-event_source-devices-hv_gpci b/Documentation/ABI/testing/sysfs-bus-event_source-devices-hv_gpci
>> index 12e2bf92783f..2eeeab9a20fa 100644
>> --- a/Documentation/ABI/testing/sysfs-bus-event_source-devices-hv_gpci
>> +++ b/Documentation/ABI/testing/sysfs-bus-event_source-devices-hv_gpci
>> @@ -80,3 +80,35 @@ Contact:	Linux on PowerPC Developer List <linuxppc-dev at lists.ozlabs.org>
>>  Description:	read only
>>  		This sysfs file exposes the cpumask which is designated to make
>>  		HCALLs to retrieve hv-gpci pmu event counter data.
>> +
>> +What:		/sys/devices/hv_gpci/interface/processor_bus_topology
>> +Date:		July 2023
>> +Contact:	Linux on PowerPC Developer List <linuxppc-dev at lists.ozlabs.org>
>> +Description:	admin read only
>> +		This sysfs file exposes the system topology information by making HCALL
>> +		H_GET_PERF_COUNTER_INFO. The HCALL is made with counter request value
>> +		PROCESSOR_BUS_TOPOLOGY(0xD0).
>> +
>> +		* This sysfs file will be created only for power10 and above platforms.
>> +
>> +		* User needs root privileges to read data from this sysfs file.
>> +
>> +		* This sysfs file will be created, only when the HCALL returns "H_SUCESS",
> 
> 		                                                                H_SUCCESS
> 
>> +		  "H_AUTHORITY" and "H_PARAMETER" as the return type.
> 
> 		            s/and/or/
> 
>> +
>> +		  HCALL with return error type "H_AUTHORITY", can be resolved during
> 
> 		                             Drop the comma ^
> 
>> +		  runtime by setting "Enable Performance Information Collection" option.
>> +
>> +		* The end user reading this sysfs file must decode the content as per
>> +		  underlying platform/firmware.
>> +
>> +		Possible error codes while reading this sysfs file:
>> +
>> +		* "-EPERM" : Partition is not permitted to retrieve performance information,
>> +			    required to set "Enable Performance Information Collection" option.
>> +
>> +		* "-EIO" : Can't retrieve system information because of invalid buffer length/invalid address
>> +			   or because of some hardware error. Refer getPerfCountInfo documentation for
> 
> 			                                      Refer to
> 
>> +			   more information.
>> +
>> +		* "-EFBIG" : System information exceeds PAGE_SIZE.
>