Re: [PATCH] powerpc/powernv: Move SCOM access code into powernv platform

[Andrew Donnellan <ajd@linux.ibm.com>]

On 8/5/19 10:27 pm, Michael Ellerman wrote:
> Andrew Donnellan <ajd@linux.ibm.com> writes:
> 
>> The powernv platform is the only one that directly accesses SCOMs. Move the
>> support code to platforms/powernv, and get rid of the PPC_SCOM Kconfig
>> option, as SCOM support is always selected when compiling for powernv.
> 
> This code was used on WSP / A2, back in the past which is why it
> originally lived in sysdev.
> 
>> This also means that the Kconfig item for CONFIG_SCOM_DEBUGFS will actually
>> show up in menuconfig, as previously it was the only labelled option in
>> sysdev/Kconfig and wasn't actually in a menu.
>>
>> Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com>
>> ---
>>   arch/powerpc/include/asm/scom.h                   | 4 ++--
> 
> Can't scom.h move into powernv as well?
> 

...looks like it can.

> And do we even need the whole scom_controller abstraction?

Probably not. Looks like there's some completely dead code in there too.

Will send a v2.


> 
> If we ever have another platform that needs it we can always bring it
> back.
> 
> cheers
> 
>>   arch/powerpc/platforms/powernv/Kconfig            | 5 ++++-
>>   arch/powerpc/platforms/powernv/Makefile           | 2 +-
>>   arch/powerpc/{sysdev => platforms/powernv}/scom.c | 0
>>   arch/powerpc/sysdev/Kconfig                       | 7 -------
>>   arch/powerpc/sysdev/Makefile                      | 2 --
>>   6 files changed, 7 insertions(+), 13 deletions(-)
>>   rename arch/powerpc/{sysdev => platforms/powernv}/scom.c (100%)
>>
>> diff --git a/arch/powerpc/include/asm/scom.h b/arch/powerpc/include/asm/scom.h
>> index f5cde45b1161..acc6532a9a9e 100644
>> --- a/arch/powerpc/include/asm/scom.h
>> +++ b/arch/powerpc/include/asm/scom.h
>> @@ -23,7 +23,7 @@
>>   
>>   #ifdef __KERNEL__
>>   #ifndef __ASSEMBLY__
>> -#ifdef CONFIG_PPC_SCOM
>> +#ifdef CONFIG_PPC_POWERNV
>>   
>>   /*
>>    * The SCOM bus is a sideband bus used for accessing various internal
>> @@ -161,7 +161,7 @@ static inline int scom_write(scom_map_t map, u64 reg, u64 value)
>>   }
>>   
>>   
>> -#endif /* CONFIG_PPC_SCOM */
>> +#endif /* CONFIG_PPC_POWERNV */
>>   #endif /* __ASSEMBLY__ */
>>   #endif /* __KERNEL__ */
>>   #endif /* _ASM_POWERPC_SCOM_H */
>> diff --git a/arch/powerpc/platforms/powernv/Kconfig b/arch/powerpc/platforms/powernv/Kconfig
>> index 850eee860cf2..938803eab0ad 100644
>> --- a/arch/powerpc/platforms/powernv/Kconfig
>> +++ b/arch/powerpc/platforms/powernv/Kconfig
>> @@ -12,7 +12,6 @@ config PPC_POWERNV
>>   	select EPAPR_BOOT
>>   	select PPC_INDIRECT_PIO
>>   	select PPC_UDBG_16550
>> -	select PPC_SCOM
>>   	select ARCH_RANDOM
>>   	select CPU_FREQ
>>   	select PPC_DOORBELL
>> @@ -47,3 +46,7 @@ config PPC_VAS
>>   	  VAS adapters are found in POWER9 based systems.
>>   
>>   	  If unsure, say N.
>> +
>> +config SCOM_DEBUGFS
>> +	bool "Expose SCOM controllers via debugfs"
>> +	depends on DEBUG_FS
>> diff --git a/arch/powerpc/platforms/powernv/Makefile b/arch/powerpc/platforms/powernv/Makefile
>> index da2e99efbd04..4b1644150135 100644
>> --- a/arch/powerpc/platforms/powernv/Makefile
>> +++ b/arch/powerpc/platforms/powernv/Makefile
>> @@ -4,12 +4,12 @@ obj-y			+= idle.o opal-rtc.o opal-nvram.o opal-lpc.o opal-flash.o
>>   obj-y			+= rng.o opal-elog.o opal-dump.o opal-sysparam.o opal-sensor.o
>>   obj-y			+= opal-msglog.o opal-hmi.o opal-power.o opal-irqchip.o
>>   obj-y			+= opal-kmsg.o opal-powercap.o opal-psr.o opal-sensor-groups.o
>> +obj-y			+= opal-xscom.o scom.o
>>   
>>   obj-$(CONFIG_SMP)	+= smp.o subcore.o subcore-asm.o
>>   obj-$(CONFIG_PCI)	+= pci.o pci-ioda.o npu-dma.o pci-ioda-tce.o
>>   obj-$(CONFIG_CXL_BASE)	+= pci-cxl.o
>>   obj-$(CONFIG_EEH)	+= eeh-powernv.o
>> -obj-$(CONFIG_PPC_SCOM)	+= opal-xscom.o
>>   obj-$(CONFIG_MEMORY_FAILURE)	+= opal-memory-errors.o
>>   obj-$(CONFIG_OPAL_PRD)	+= opal-prd.o
>>   obj-$(CONFIG_PERF_EVENTS) += opal-imc.o
>> diff --git a/arch/powerpc/sysdev/scom.c b/arch/powerpc/platforms/powernv/scom.c
>> similarity index 100%
>> rename from arch/powerpc/sysdev/scom.c
>> rename to arch/powerpc/platforms/powernv/scom.c
>> diff --git a/arch/powerpc/sysdev/Kconfig b/arch/powerpc/sysdev/Kconfig
>> index e0dbec780fe9..7808d279ff1d 100644
>> --- a/arch/powerpc/sysdev/Kconfig
>> +++ b/arch/powerpc/sysdev/Kconfig
>> @@ -28,13 +28,6 @@ config PPC_MSI_BITMAP
>>   source "arch/powerpc/sysdev/xics/Kconfig"
>>   source "arch/powerpc/sysdev/xive/Kconfig"
>>   
>> -config PPC_SCOM
>> -	bool
>> -
>> -config SCOM_DEBUGFS
>> -	bool "Expose SCOM controllers via debugfs"
>> -	depends on PPC_SCOM && DEBUG_FS
>> -
>>   config GE_FPGA
>>   	bool
>>   
>> diff --git a/arch/powerpc/sysdev/Makefile b/arch/powerpc/sysdev/Makefile
>> index aaf23283ba0c..35d52d1d2fc0 100644
>> --- a/arch/powerpc/sysdev/Makefile
>> +++ b/arch/powerpc/sysdev/Makefile
>> @@ -51,8 +51,6 @@ ifdef CONFIG_SUSPEND
>>   obj-$(CONFIG_PPC_BOOK3S_32)	+= 6xx-suspend.o
>>   endif
>>   
>> -obj-$(CONFIG_PPC_SCOM)		+= scom.o
>> -
>>   obj-$(CONFIG_PPC_EARLY_DEBUG_MEMCONS)	+= udbg_memcons.o
>>   
>>   obj-$(CONFIG_PPC_XICS)		+= xics/
>> -- 
>> 2.20.1
> 

-- 
Andrew Donnellan              OzLabs, ADL Canberra
ajd@linux.ibm.com             IBM Australia Limited