Re: [RFC 1/6] powerpc:/drc Define interface to acquire arch-specific drc info

[Michael Bringmann <mwb@linux.vnet.ibm.com>]

On 1/25/19 10:09 AM, Michael Bringmann wrote:
> Adding Nathan Lynch
> 
> On 1/24/19 6:04 PM, Tyrel Datwyler wrote:
>> On 12/14/2018 12:50 PM, Michael Bringmann wrote:
>>> Define interface to acquire arch-specific drc info to match against
>>> hotpluggable devices.  The current implementation exposes several
>>> pseries-specific dynamic memory properties in generic kernel code.
>>> This patch set provides an interface to pull that code out of the
>>> generic kernel.
>>>
>>> Signed-off-by: Michael Bringmann <mwb@linux.vnet.ibm.com>
>>> ---
>>>  include/linux/topology.h |    9 +++++++++
>>>  1 file changed, 9 insertions(+)
>>>
>>> diff --git a/include/linux/topology.h b/include/linux/topology.h
>>> index cb0775e..df97f5f 100644
>>> --- a/include/linux/topology.h
>>> +++ b/include/linux/topology.h
>>> @@ -44,6 +44,15 @@
>>
>> As far as I know pseries is the only platform that uses DR connectors, and I
>> highly doubt that any other powerpc platform or arch ever will. So, I'm not sure
>> that this is really generic enough to belong in topology.h. If anything I would
>> suggest putting this in an include in arch/powerpc/include/ named something like
>> drcinfo.h or pseries-drc.h. That will make it visible to modules like rpaphp
>> that want/need to use this functionality.

It looks like the 'rpaphp' and 'rpadlpar_io' modules are also dependent upon the
powerpc platform.  Shouldn't the relevant source files be moved completely to the
powerpc-specific directories out of drivers/pci/hotplug as well?

drivers/pci/hotplug/Kconfig has:

config HOTPLUG_PCI_RPA
        tristate "RPA PCI Hotplug driver"
        depends on PPC_PSERIES && EEH
        help
          Say Y here if you have a RPA system that supports PCI Hotplug.

          To compile this driver as a module, choose M here: the
          module will be called rpaphp.

          When in doubt, say N.

config HOTPLUG_PCI_RPA_DLPAR
        tristate "RPA Dynamic Logical Partitioning for I/O slots"
        depends on HOTPLUG_PCI_RPA
        help
          Say Y here if your system supports Dynamic Logical Partitioning
          for I/O slots.

          To compile this driver as a module, choose M here: the
          module will be called rpadlpar_io.

          When in doubt, say N.

Michael

>>
>> -Tyrel
>>
>>>  
>>>  int arch_update_cpu_topology(void);
>>>  
>>> +int arch_find_drc_match(struct device_node *dn,
>>> +			bool (*usercb)(struct device_node *dn,
>>> +				u32 drc_index, char *drc_name,
>>> +				char *drc_type, u32 drc_power_domain,
>>> +				void *data),
>>> +			char *opt_drc_type, char *opt_drc_name,
>>> +			bool match_drc_index, bool ck_php_type,
>>> +			void *data);
>>> +
>>>  /* Conform to ACPI 2.0 SLIT distance definitions */
>>>  #define LOCAL_DISTANCE		10
>>>  #define REMOTE_DISTANCE		20
>>>
>>
>>
> 

-- 
Michael W. Bringmann
Linux Technology Center
IBM Corporation
Tie-Line  363-5196
External: (512) 286-5196
Cell:       (512) 466-0650
mwb@linux.vnet.ibm.com