[PATCH v19 2/7] firmware: arm_rmm: Check for RMI support at init

[Gavin Shan]

On 9/24/26 11:51 PM, Suzuki K Poulose wrote:
> From: Steven Price <steven.price at arm.com>
> 
> 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.
> 
> Signed-off-by: Steven Price <steven.price at arm.com>
> Co-developed-by: Suzuki K Poulose <suzuki.poulose at arm.com>
> Signed-off-by: Suzuki K Poulose <suzuki.poulose at arm.com>
> ---
> v19:
>   * Read all implemented RmiFeatureRegisters - 5
>   * Use ARRAY_SIZE(rmi_feat_reg_cache) for the loop in rmi_read_features()
>   * Fold rmi_features() into rmi_read_features
>   * Fix comment for rmi_smccc_invoke()
>   * Drop default y
>   * Add retry for RMI_BLOCKED and return to caller
> v18:
>   * Always use arm_smccc_1_2_invoke() for all RMIs making sure the unsused
>     parameters are 0 - Sashiko
>   * Move rmi_features() calls away from the arm-rmi-cmds.h to rmi.c - Gavin
> v17:
>   * Rename ARM_RMM to ARM_RMM_RMI to make it easier to add Guest facing RSI
>     support, which is also in progress
> v16:
>   * Update Kconfig text to include PCIe TDISP.
>   * Export rmi_feat_reg() here rather than in a later commit.
> v15:
>   * The code is moved again, this time into the 'firmware' directory.
> v14:
>   * This moves the basic RMI setup into the 'kernel' directory. This is
>     because RMI will be used for some features outside of KVM so should
>     be available even if KVM isn't compiled in.
> ---
>   arch/arm64/Kconfig                |   1 +
>   arch/arm64/kernel/cpufeature.c    |   1 +
>   drivers/firmware/Kconfig          |   1 +
>   drivers/firmware/Makefile         |   1 +
>   drivers/firmware/arm_rmm/Kconfig  |  25 +++++++
>   drivers/firmware/arm_rmm/Makefile |   2 +
>   drivers/firmware/arm_rmm/rmi.c    | 109 ++++++++++++++++++++++++++++++
>   include/linux/arm-rmi-cmds.h      |  48 +++++++++++++
>   8 files changed, 188 insertions(+)
>   create mode 100644 drivers/firmware/arm_rmm/Kconfig
>   create mode 100644 drivers/firmware/arm_rmm/Makefile
>   create mode 100644 drivers/firmware/arm_rmm/rmi.c
>   create mode 100644 include/linux/arm-rmi-cmds.h
> 

[...]

> diff --git a/drivers/firmware/arm_rmm/Makefile b/drivers/firmware/arm_rmm/Makefile
> new file mode 100644
> index 0000000000000..65171988fdcae
> --- /dev/null
> +++ b/drivers/firmware/arm_rmm/Makefile
> @@ -0,0 +1,2 @@
> +
> +obj-$(CONFIG_ARM_RMM_RMI)	= rmi.o

Unnecessary blank line at the top in Makefile. Besides, why doesn't this come
as below? :)

obj-$(CONFIG_ARM_RMM_RMI)	+= rmi.o

Thanks,
Gavin