On Sun, 2016-05-29 at 12:53 +0200, Jonas Gorski wrote:
> Maybe a better solution here would be to create a new symbol
> fw_passed_dtb and let the code store a1 in there if a0 is -2, or
> __appended_dtb in case it is valid? Then we wouldn't need to special
> case APPENDED_DTB for any mach wanting to use it, and they can just
> check fw_passed_dtb.
>
> something like:
>
> arch/mips/kernel/head.S:
> ...
>
> #ifdef CONFIG_USE_OF
> li t1, -2
> beq a0, t1, dtb_found
> move t0, a0
>
> #ifdef CONFIG_MIPS_RAW_APPENDED_DTB
> PTR_LA t0, __appended_dtb
>
> #ifdef CONFIG_CPU_BIG_ENDIAN
> li t1, 0xd00dfeed
> #else
> li t1, 0xedfe0dd0
> #endif
> lw t2, (t0)
> bne t1, t2, no_dtb_found
> nop
>
> #endif
> no_dtb_found:
> li t0, 0
> dtb_found:
> LONG_S t0, fw_passed_dtb
> #endif
That prefers the wrong DTB in case both are present. I propose this
instead:
#ifdef CONFIG_USE_OF
#ifdef CONFIG_MIPS_RAW_APPENDED_DTB
PTR_LA t0, __appended_dtb
#ifdef CONFIG_CPU_BIG_ENDIAN
li t1, 0xd00dfeed
#else
li t1, 0xedfe0dd0
#endif
lw t2, (t0)
beq t1, t2, dtb_found
nop
#endif
li t1, -2
beq a0, t1, dtb_found
move t0, a1
no_dtb_found:
li t0, 0
dtb_found:
LONG_S t0, fw_passed_dtb
#endif
