[Buildroot] [PATCH 1/3] arch/csky: Add ck860 and vdsp compiler options

[Thomas Petazzoni]

Hello Guo,

Thanks for this new csky related contribution. See below some comments.

On Tue,  7 May 2019 17:47:20 +0800
guoren at kernel.org wrote:

> From: Guo Ren <ren_guo at c-sky.com>
> 
> The ck860 is C-SKY abiv2 cpu series and it could support SMP and vdsp
> instructions set. Add the compiler options for them.
> 
> Signed-off-by: Guo Ren <ren_guo at c-sky.com>
> ---
>  arch/Config.in.csky | 33 ++++++++++++++++++++-------------
>  1 file changed, 20 insertions(+), 13 deletions(-)
> 
> diff --git a/arch/Config.in.csky b/arch/Config.in.csky
> index e88e4e2..bbff600 100644
> --- a/arch/Config.in.csky
> +++ b/arch/Config.in.csky
> @@ -13,19 +13,26 @@ config BR2_ck807
>  config BR2_ck810
>  	bool "ck810"
>  
> +config BR2_ck860
> +	bool "ck860"
> +
>  endchoice
>  
>  config BR2_CSKY_FPU
>  	bool "Enable FPU coprocessor"
> -	depends on BR2_ck810 || BR2_ck807
> +	depends on BR2_ck807 || BR2_ck810 || BR2_ck860
>  	help
>  	  You can say N here if your C-SKY CPU doesn't have a
>  	  Floating-Point Coprocessor or if you don't need FPU support
>  	  for your user-space programs.
>  
> -config BR2_CSKY_DSP
> -	bool "Enable DSP enhanced instructions"
> -	depends on BR2_ck810 || BR2_ck807

Why is this option being removed ? This is not explained in the commit
log.

> +config BR2_CSKY_VDSP
> +	bool "Enable VDSP 3.0 enhanced instructions Co-processor"
> +	depends on BR2_ck860
> +
> +config BR2_GCC_TARGET_FLOAT_ABI
> +	default "soft"		if !BR2_CSKY_FPU
> +	default "hard"		if BR2_CSKY_FPU

This should be in a separate patch, it's not a change that is directly
related.

>  config BR2_ARCH
>  	default "csky"
> @@ -34,15 +41,15 @@ config BR2_ENDIAN
>  	default "LITTLE"
>  
>  config BR2_GCC_TARGET_CPU
> -	default "ck610"		if (BR2_ck610 && !BR2_CSKY_FPU && !BR2_CSKY_DSP)
> -	default "ck807"		if (BR2_ck807 && !BR2_CSKY_FPU && !BR2_CSKY_DSP)
> -	default "ck807e"	if (BR2_ck807 && !BR2_CSKY_FPU &&  BR2_CSKY_DSP)
> -	default "ck807f"	if (BR2_ck807 &&  BR2_CSKY_FPU && !BR2_CSKY_DSP)
> -	default "ck807ef"	if (BR2_ck807 &&  BR2_CSKY_FPU &&  BR2_CSKY_DSP)
> -	default "ck810"		if (BR2_ck810 && !BR2_CSKY_FPU && !BR2_CSKY_DSP)
> -	default "ck810e"	if (BR2_ck810 && !BR2_CSKY_FPU &&  BR2_CSKY_DSP)
> -	default "ck810f"	if (BR2_ck810 &&  BR2_CSKY_FPU && !BR2_CSKY_DSP)
> -	default "ck810ef"	if (BR2_ck810 &&  BR2_CSKY_FPU &&  BR2_CSKY_DSP)
> +	default "ck610"		if (BR2_ck610 && !BR2_CSKY_FPU && !BR2_CSKY_VDSP)
> +	default "ck807"		if (BR2_ck807 && !BR2_CSKY_FPU && !BR2_CSKY_VDSP)
> +	default "ck807f"	if (BR2_ck807 &&  BR2_CSKY_FPU && !BR2_CSKY_VDSP)
> +	default "ck810"		if (BR2_ck810 && !BR2_CSKY_FPU && !BR2_CSKY_VDSP)
> +	default "ck810f"	if (BR2_ck810 &&  BR2_CSKY_FPU && !BR2_CSKY_VDSP)
> +	default "ck860"		if (BR2_ck860 && !BR2_CSKY_FPU && !BR2_CSKY_VDSP)
> +	default "ck860f"	if (BR2_ck860 &&  BR2_CSKY_FPU && !BR2_CSKY_VDSP)
> +	default "ck860v"	if (BR2_ck860 && !BR2_CSKY_FPU &&  BR2_CSKY_VDSP)
> +	default "ck860fv"	if (BR2_ck860 &&  BR2_CSKY_FPU &&  BR2_CSKY_VDSP)

Perhaps this is becoming too much, and we should adopt a solution
similar to the one in arch/arch.mk.riscv. I.e, drop the
BR2_GCC_TARGET_CPU definition from arch/Config.in.csky, and add a file
arch/arch.mk.csky that contains:

ifeq ($(BR2_csky),y)

ifeq ($(BR2_ck610),y)
GCC_TARGET_CPU := ck610
else ifeq ($(BR2_ck807),y)
GCC_TARGET_CPU := ck807
else ifeq ($(BR2_ck810),y)
GCC_TARGET_CPU := ck810
else ifeq ($(BR2_ck860),y)
GCC_TARGET_CPU := ck860
endif

ifeq ($(BR2_CSKY_FPU),y)
GCC_TARGET_CPU := $(GCC_TARGET_CPU)f
endif

ifeq ($(BR2_CSKY_VDSP),y)
GCC_TARGET_CPU := $(GCC_TARGET_CPU)v
endif

endif

Best regards,

Thomas
-- 
Thomas Petazzoni, CTO, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com