diff options
| author | Scott Wood <scottwood@freescale.com> | 2013-08-20 19:33:12 -0500 |
|---|---|---|
| committer | Scott Wood <scottwood@freescale.com> | 2013-08-20 19:33:12 -0500 |
| commit | beb2dc0a7a84be003ce54e98b95d65cc66e6e536 (patch) | |
| tree | a30c97effb8f723cccbc343306df4c7b6ab0047b /arch/powerpc/boot | |
| parent | d52459ca3047435aa5d7957e50857fc7ba193411 (diff) | |
powerpc: Convert some mftb/mftbu into mfspr
Some CPUs (such as e500v1/v2) don't implement mftb and will take a
trap. mfspr should work on everything that has a timebase, and is the
preferred instruction according to ISA v2.06.
Currently we get away with mftb on 85xx because the assembler converts
it to mfspr due to -Wa,-me500. However, that flag has other effects
that are undesireable for certain targets (e.g. lwsync is converted to
sync), and is hostile to multiplatform kernels. Thus we would like to
stop setting it for all e500-family builds.
mftb/mftbu instances which are in 85xx code or common code are
converted. Instances which will never run on 85xx are left alone.
Signed-off-by: Scott Wood <scottwood@freescale.com>
Diffstat (limited to 'arch/powerpc/boot')
| -rw-r--r-- | arch/powerpc/boot/ppc_asm.h | 3 | ||||
| -rw-r--r-- | arch/powerpc/boot/util.S | 10 |
2 files changed, 8 insertions, 5 deletions
diff --git a/arch/powerpc/boot/ppc_asm.h b/arch/powerpc/boot/ppc_asm.h index 1c2c2817f9b7..eb0e98be69e0 100644 --- a/arch/powerpc/boot/ppc_asm.h +++ b/arch/powerpc/boot/ppc_asm.h @@ -59,4 +59,7 @@ #define r30 30 #define r31 31 +#define SPRN_TBRL 268 +#define SPRN_TBRU 269 + #endif /* _PPC64_PPC_ASM_H */ diff --git a/arch/powerpc/boot/util.S b/arch/powerpc/boot/util.S index 427ddfc11991..5143228e3e5f 100644 --- a/arch/powerpc/boot/util.S +++ b/arch/powerpc/boot/util.S @@ -71,18 +71,18 @@ udelay: add r4,r4,r5 addi r4,r4,-1 divw r4,r4,r5 /* BUS ticks */ -1: mftbu r5 - mftb r6 - mftbu r7 +1: mfspr r5, SPRN_TBRU + mfspr r6, SPRN_TBRL + mfspr r7, SPRN_TBRU cmpw 0,r5,r7 bne 1b /* Get [synced] base time */ addc r9,r6,r4 /* Compute end time */ addze r8,r5 -2: mftbu r5 +2: mfspr r5, SPRN_TBRU cmpw 0,r5,r8 blt 2b bgt 3f - mftb r6 + mfspr r6, SPRN_TBRL cmpw 0,r6,r9 blt 2b 3: blr |