[U-Boot] [PATCH 2/2] armv8: ls1043a: Discard the needless cpu nodes

[Wenbin Song]

Hi Prabhakar,

In my opinion, this is a common feature for all Layerscapes. As I know, all chips belonged to Layerscape have the capacity to disable some cores, just like ls1043a /ls1023a. 
If we will support another variant in the future, for example: ls1046a/ls1026a, just configure it rather than modify the codes.
Am I correct?

Best Regards
Wenbin Song


-----Original Message-----
From: Prabhakar Kushwaha 
Sent: Thursday, November 30, 2017 12:56 PM
To: Wenbin Song <wenbin.song at nxp.com>; York Sun <york.sun at nxp.com>; Ran Wang <ran.wang_1 at nxp.com>; Mingkai Hu <mingkai.hu at nxp.com>; u-boot at lists.denx.de
Cc: Wenbin Song <wenbin.song at nxp.com>
Subject: RE: [PATCH 2/2] armv8: ls1043a: Discard the needless cpu nodes


> -----Original Message-----
> From: Wenbin song [mailto:wenbin.song at nxp.com]
> Sent: Thursday, November 30, 2017 8:27 AM
> To: York Sun <york.sun at nxp.com>; Prabhakar Kushwaha 
> <prabhakar.kushwaha at nxp.com>; Ran Wang <ran.wang_1 at nxp.com>; Mingkai 
> Hu <mingkai.hu at nxp.com>; u-boot at lists.denx.de
> Cc: Wenbin Song <wenbin.song at nxp.com>
> Subject: [PATCH 2/2] armv8: ls1043a: Discard the needless cpu nodes
> 
> Using "cpu_pos_mask()" function to detect the real online cpus, and 
> discard the needless cpu nodes on kernel dft.
> 
> Signed-off-by: Wenbin Song <wenbin.song at nxp.com>
> ---
>  arch/arm/cpu/armv8/fsl-layerscape/Kconfig |  4 ++++
>  arch/arm/cpu/armv8/fsl-layerscape/fdt.c   | 32
> +++++++++++++++++++++++++++++++
>  2 files changed, 36 insertions(+)
> 
> diff --git a/arch/arm/cpu/armv8/fsl-layerscape/Kconfig
> b/arch/arm/cpu/armv8/fsl-layerscape/Kconfig
> index 47145a2432..971a98c6cc 100644
> --- a/arch/arm/cpu/armv8/fsl-layerscape/Kconfig
> +++ b/arch/arm/cpu/armv8/fsl-layerscape/Kconfig
> @@ -176,6 +176,10 @@ config HAS_FEATURE_ENHANCED_MSI
>  	bool
>  	default y if ARCH_LS1043A
> 
> +config DISCARD_OFFLINE_CPU_NODES
> +	bool
> +	default y if ARCH_LS1043A
> +

As per understanding this feature is for taking care of SoC personalities with reduced cores. 

Why a new config is required? Why cannot this be taken care at run time by reading SVR.

-pk