Re: [PATCH v18 2/7] firmware: arm_rmm: Check for RMI support at init

[Suzuki K Poulose <suzuki.poulose@arm.com>]

On 19/09/2026 02:27, Jonathan Cameron wrote:
>> Query the RMI version number and check if it is a compatible version.
>> The first two feature registers are read and exposed for future code to
>> use.
>>
>> We only support this for Little Endian kernels, the Big Endian kernel
>> support is anyway marked BROKEN and is being removed.
> 
> Can we have a small comment here on why the default is y
> 
> It's a big thing to opt into by default.  Feels like defconfig
> material maybe but not in the Kconfig defaults unless I'm missing
> something.

We need this for KVM arm64. I could drop the default here and
KVM selects this anyways. But, how far do we go on this ?
Do we need to be able to disable this completely even for KVM ?

As such it is a relatively smaller blob:

$ size drivers/firmware/arm_rmm/rmi.o
    text    data     bss     dec     hex filename
    7477     572       1    8050    1f72 drivers/firmware/arm_rmm/rmi.o

Cheers
Suzuki

> 
> 
>>
>> Signed-off-by: Steven Price <steven.price@arm.com>
>> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
> 
>> diff --git a/drivers/firmware/arm_rmm/Kconfig b/drivers/firmware/arm_rmm/Kconfig
>> new file mode 100644
>> index 000000000000..82724ee23186
>> --- /dev/null
>> +++ b/drivers/firmware/arm_rmm/Kconfig
>> @@ -0,0 +1,26 @@
>> +
>> +config ARCH_SUPPORTS_RMM
>> +	bool
>> +
>> +config ARM_RMM_RMI
>> +	bool "Realm Management Interface (RMI) Support"
>> +	depends on ARCH_SUPPORTS_RMM
>> +	default y
> Really? Why?

>