Re: [PATCH] MIPS: dsp: Add assembler support for DSP ASEs.

[Florian Fainelli <florian@openwrt.org>]

Hi Steven,

Le 12/07/12 05:53, Steven J. Hill a écrit :
> From: "Steven J. Hill" <sjhill@mips.com>
>
> Newer toolchains support the DSP and DSP Rev2 instructions. This patch
> performs a check for that support and adds compiler and assembler
> flags for only the files that need use those instructions.
>
> Signed-off-by: Steven J. Hill <sjhill@mips.com>
> ---
>   arch/mips/include/asm/mipsregs.h |   53 ++++++++++++++++++++++++++------------
>   arch/mips/kernel/Makefile        |   24 +++++++++++++++++
>   2 files changed, 60 insertions(+), 17 deletions(-)
>
> --- a/arch/mips/kernel/Makefile
> +++ b/arch/mips/kernel/Makefile
> @@ -99,4 +99,28 @@ obj-$(CONFIG_HW_PERF_EVENTS) += perf_event_mipsxx.o
>
>   obj-$(CONFIG_JUMP_LABEL)      += jump_label.o
>
> +ifeq ($(CONFIG_CPU_MIPS32), y)
> +#
> +# Check if assembler supports DSP ASE
> +#
> +ifeq ($(call cc-option-yn,-mdsp), y)
> +CFLAGS_signal.o                        = -mdsp -DHAVE_AS_DSP
> +CFLAGS_signal32.o              = -mdsp -DHAVE_AS_DSP
> +CFLAGS_process.o               = -mdsp -DHAVE_AS_DSP
> +CFLAGS_branch.o                        = -mdsp -DHAVE_AS_DSP
> +CFLAGS_ptrace.o                        = -mdsp -DHAVE_AS_DSP
> +endif
> +
> +#
> +# Check if assembler supports DSP ASE Rev2
> +#
> +ifeq ($(call cc-option-yn,-mdsp2), y)
> +CFLAGS_signal.o                        = -mdsp2 -DHAVE_AS_DSP
> +CFLAGS_signal32.o              = -mdsp2 -DHAVE_AS_DSP
> +CFLAGS_process.o               = -mdsp2 -DHAVE_AS_DSP
> +CFLAGS_branch.o                        = -mdsp2 -DHAVE_AS_DSP
> +CFLAGS_ptrace.o                        = -mdsp2 -DHAVE_AS_DSP
Should not this be -mdspr2 here? My GCC man page suggests that.

By the way, should not we also check that we are building for a 
MIPS32_R2 CPU when checking for -mdsp2?
> +endif
> +endif
> +
I would simplify this like this:

ifeq ($(CONFIG_CPU_MIPS32),y)
CFLAGS_DSP = -DHAVE_AS_DSP
ifeq ($(call cc-option-yn,-mdsp),y)
CFLAGS_DSP += -mdsp
endif
ifeq ($(call cc-option-yn,-mdsp2),y)
CFLAGS-DSP += -mdsp2
endif

CFLAGS_signal.o         = $(CFLAGS_DSP)
...
CFLAGS_ptrace.o         = $(CFLAGS_DSP)
endif

such that the day you can take advantage of a third DSP flavor it's only 
3 lines worth of Makefile to get it used, and you only have one place 
where you need to change CFLAGS.
--
Florian