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authorOlof Johansson <olof@lixom.net>2006-10-04 23:41:41 -0500
committerPaul Mackerras <paulus@samba.org>2006-10-16 16:32:25 +1000
commit5b43d20a4d12d94f258bbbca5fa4df8ff8a17848 (patch)
tree83b72628e99850fde1a49c435cbeee6e5750f942 /arch/powerpc/kernel/cpu_setup_ppc970.S
parentd04c56f73c30a5e593202ecfcf25ed43d42363a2 (diff)
[POWERPC] powerpc: Enable DEEPNAP power savings mode on 970MP
Without this patch, on an idle system I get: cpu-power-0:21.638 cpu-power-1:27.102 cpu-power-2:29.343 cpu-power-3:25.784 Total: 103.8W With this patch: cpu-power-0:11.730 cpu-power-1:17.185 cpu-power-2:18.547 cpu-power-3:17.528 Total: 65.0W If I lower HZ to 100, I can get it as low as: cpu-power-0:10.938 cpu-power-1:16.021 cpu-power-2:17.245 cpu-power-3:16.145 Total: 60.2W Another (older) Quad G5 went from 54W to 39W at HZ=250. Coming back out of Deep Nap takes 40-70 cycles longer than coming back from just Nap (which already takes quite a while). I don't think it'll be a performance issue (interrupt latency on an idle system), but in case someone does measurements feel free to report them. Signed-off-by: Olof Johansson <olof@lixom.net> Acked-by: Michael Buesch <mb@bu3sch.de> Signed-off-by: Paul Mackerras <paulus@samba.org>
Diffstat (limited to 'arch/powerpc/kernel/cpu_setup_ppc970.S')
-rw-r--r--arch/powerpc/kernel/cpu_setup_ppc970.S16
1 files changed, 16 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/cpu_setup_ppc970.S b/arch/powerpc/kernel/cpu_setup_ppc970.S
index 652594891d5..bf118c38575 100644
--- a/arch/powerpc/kernel/cpu_setup_ppc970.S
+++ b/arch/powerpc/kernel/cpu_setup_ppc970.S
@@ -83,6 +83,22 @@ _GLOBAL(__setup_cpu_ppc970)
rldimi r0,r11,52,8 /* set NAP and DPM */
li r11,0
rldimi r0,r11,32,31 /* clear EN_ATTN */
+ b load_hids /* Jump to shared code */
+
+
+_GLOBAL(__setup_cpu_ppc970MP)
+ /* Do nothing if not running in HV mode */
+ mfmsr r0
+ rldicl. r0,r0,4,63
+ beqlr
+
+ mfspr r0,SPRN_HID0
+ li r11,0x15 /* clear DOZE and SLEEP */
+ rldimi r0,r11,52,6 /* set DEEPNAP, NAP and DPM */
+ li r11,0
+ rldimi r0,r11,32,31 /* clear EN_ATTN */
+
+load_hids:
mtspr SPRN_HID0,r0
mfspr r0,SPRN_HID0
mfspr r0,SPRN_HID0