From 8b32bc03256c82a6a4fcb3c2520b54469b74ec82 Mon Sep 17 00:00:00 2001
From: Olof Johansson <olof@lixom.net>
Date: Wed, 7 Nov 2007 09:26:06 -0600
Subject: [PATCH] [POWERPC] pasemi: Don't enter powersaving states from
elevated astates
When the PWRficient cpus are entered into powersavings states, the
astate is automatically dropped down to 0. While we still restore it
when we come out of idle, it can still cause some weird effects with
respect to performance (especially since it takes a while to ramp up to
higher astates).
So, to avoid this, don't enter power savings when the cpufreq driver
(or user) has set higher astates than 0.
The restore is still required, since there's a chance the astate has
been raised from the other cpu while the idling one was asleep.
Signed-off-by: Olof Johansson <olof@lixom.net>
---
arch/powerpc/platforms/pasemi/cpufreq.c | 6 ++++++
arch/powerpc/platforms/pasemi/pasemi.h | 6 ++++++
arch/powerpc/platforms/pasemi/powersave.S | 11 ++++++++++-
3 files changed, 22 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/platforms/pasemi/cpufreq.c b/arch/powerpc/platforms/pasemi/cpufreq.c
index 8caa1667cf34d..58556b028a4c1 100644
--- a/arch/powerpc/platforms/pasemi/cpufreq.c
+++ b/arch/powerpc/platforms/pasemi/cpufreq.c
@@ -32,6 +32,7 @@
#include <asm/io.h>
#include <asm/prom.h>
#include <asm/time.h>
+#include <asm/smp.h>
#define SDCASR_REG 0x0100
#define SDCASR_REG_STRIDE 0x1000
@@ -124,6 +125,11 @@ static void set_astate(int cpu, unsigned int astate)
local_irq_restore(flags);
}
+int check_astate(void)
+{
+ return get_cur_astate(hard_smp_processor_id());
+}
+
void restore_astate(int cpu)
{
set_astate(cpu, current_astate);
diff --git a/arch/powerpc/platforms/pasemi/pasemi.h b/arch/powerpc/platforms/pasemi/pasemi.h
index 516acabb4e96a..c96127b029b65 100644
--- a/arch/powerpc/platforms/pasemi/pasemi.h
+++ b/arch/powerpc/platforms/pasemi/pasemi.h
@@ -16,8 +16,14 @@ extern void idle_doze(void);
/* Restore astate to last set */
#ifdef CONFIG_PPC_PASEMI_CPUFREQ
+extern int check_astate(void);
extern void restore_astate(int cpu);
#else
+static inline int check_astate(void)
+{
+ /* Always return >0 so we never power save */
+ return 1;
+}
static inline void restore_astate(int cpu)
{
}
diff --git a/arch/powerpc/platforms/pasemi/powersave.S b/arch/powerpc/platforms/pasemi/powersave.S
index 6d0fba6aab174..56f45adcd0895 100644
--- a/arch/powerpc/platforms/pasemi/powersave.S
+++ b/arch/powerpc/platforms/pasemi/powersave.S
@@ -62,7 +62,16 @@ sleep_common:
mflr r0
std r0, 16(r1)
stdu r1,-64(r1)
+#ifdef CONFIG_PPC_PASEMI_CPUFREQ
+ std r3, 48(r1)
+ /* Only do power savings when in astate 0 */
+ bl .check_astate
+ cmpwi r3,0
+ bne 1f
+
+ ld r3, 48(r1)
+#endif
LOAD_REG_IMMEDIATE(r6,MSR_DR|MSR_IR|MSR_ME|MSR_EE)
mfmsr r4
andc r5,r4,r6
@@ -73,7 +82,7 @@ sleep_common:
mtmsrd r4,0
- addi r1,r1,64
+1: addi r1,r1,64
ld r0,16(r1)
mtlr r0
blr
--
2.30.2