Re: [PATCH 17/36] cavium: Hook Cavium specifics into main arch/mips dir

[Ralf Baechle <ralf@linux-mips.org>]

On Mon, Oct 27, 2008 at 05:02:49PM -0700, David Daney wrote:

> diff --git a/arch/mips/Makefile b/arch/mips/Makefile
> index 28c55f6..0addc84 100644
> --- a/arch/mips/Makefile
> +++ b/arch/mips/Makefile
> @@ -144,6 +144,7 @@ cflags-$(CONFIG_CPU_SB1)	+= $(call cc-option,-march=sb1,-march=r5000) \
>  cflags-$(CONFIG_CPU_R8000)	+= -march=r8000 -Wa,--trap
>  cflags-$(CONFIG_CPU_R10000)	+= $(call cc-option,-march=r10000,-march=r8000) \
>  			-Wa,--trap
> +cflags-$(CONFIG_CPU_CAVIUM_OCTEON) += -march=octeon -Wa,--trap

One if my standard requirements is that contributions must build and work
with a standard FSF toolchain.  Browny points for building with even older
tools chains - the oldest supported versions are gcc 3.2 for 32-bit and
gcc 3.3 for 64-bit.

Latest binutils 2.19 (releast on 2008-10-27) have added Cavium support but
gcc 4.3 doesn't have that yet.  So you can try something like:

cflags-$(CONFIG_CPU_CAVIUM_OCTEON) += $(call cc-option,-march=octeon,-march=mips64r2) -Wa,--trap

> +core-$(CONFIG_CPU_CAVIUM_OCTEON)	+= arch/mips/cavium-octeon/executive/

-fkeep-ceo-inline ;-)

> +ifdef CONFIG_CAVIUM_OCTEON_2ND_KERNEL
> +load-$(CONFIG_CPU_CAVIUM_OCTEON)	+= 0xffffffff84100000
> +else
> +load-$(CONFIG_CPU_CAVIUM_OCTEON) 	+= 0xffffffff81100000
> +endif

I'm thinking about a more elegant solution for this.  PIC code sucks a blue
whale through a dialysis filter so I hope we can find something better.
Until then this is certainly acceptable.

> diff --git a/arch/mips/kernel/Makefile b/arch/mips/kernel/Makefile
> index b1372c2..93ff9c4 100644
> --- a/arch/mips/kernel/Makefile
> +++ b/arch/mips/kernel/Makefile
> @@ -43,6 +43,7 @@ obj-$(CONFIG_CPU_SB1)		+= r4k_fpu.o r4k_switch.o
>  obj-$(CONFIG_CPU_TX39XX)	+= r2300_fpu.o r2300_switch.o
>  obj-$(CONFIG_CPU_TX49XX)	+= r4k_fpu.o r4k_switch.o
>  obj-$(CONFIG_CPU_VR41XX)	+= r4k_fpu.o r4k_switch.o
> +obj-$(CONFIG_CPU_CAVIUM_OCTEON)	+= octeon_switch.o

I guess you could just use the normal r4k_fpu.o r4k_switch.o here and handle
the rest of the Cavium bits like other non-standard architecture features
in switch_to() and finish_arch_switch:

#define switch_to(prev, next, last)                                     \
do {                                                                    \
        __mips_mt_fpaff_switch_to(prev);                                \
        if (cpu_has_dsp)                                                \
                __save_dsp(prev);                                       \
        if (cpu_has_cavium)                                             \
                __save_cavium_stuff(prev);                              \
        (last) = resume(prev, next, task_thread_info(next));            \
} while (0)

#define finish_arch_switch(prev)                                        \
do {                                                                    \
        if (cpu_has_cavium)                                             \
                __restore_cavium_stuff(prev);                           \
        if (cpu_has_dsp)                                                \
                __restore_dsp(current);                                 \
        if (cpu_has_userlocal)                                          \
                write_c0_userlocal(current_thread_info()->tp_value);    \
        __restore_watch();                                              \
} while (0)

?

> +CFLAGS_ptrace.o	= -I$(OCTEON_ROOT)/executive

Huh?

>  obj-$(CONFIG_CPU_TX49XX)	+= c-r4k.o cex-gen.o tlb-r4k.o
>  obj-$(CONFIG_CPU_VR41XX)	+= c-r4k.o cex-gen.o tlb-r4k.o
> +obj-$(CONFIG_CPU_CAVIUM_OCTEON)	+= c-octeon.o cex-oct.o tlb-r4k.o
>  
>  obj-$(CONFIG_IP22_CPU_SCACHE)	+= sc-ip22.o
>  obj-$(CONFIG_R5000_CPU_SCACHE)  += sc-r5k.o
> @@ -34,3 +35,7 @@ obj-$(CONFIG_RM7000_CPU_SCACHE)	+= sc-rm7k.o
>  obj-$(CONFIG_MIPS_CPU_SCACHE)	+= sc-mips.o
>  
>  EXTRA_CFLAGS += -Werror
> +
> +OCTEON_ROOT = $(srctree)/arch/mips/cavium-octeon
> +CFLAGS_c-octeon.o	= -I$(OCTEON_ROOT)/executive

I've not noticed anything in c-octeon.c which would require this -I flag.

  Ralf