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Subject[PATCH v2 2/3] powerpc/powernv/idle: save-restore DAWR0,DAWRX0 for P10
Date
Additional registers DAWR0, DAWRX0 may be lost on Power 10 for
stop levels < 4.
Therefore save the values of these SPRs before entering a "stop"
state and restore their values on wakeup.

Signed-off-by: Pratik Rajesh Sampat <psampat@linux.ibm.com>
---
arch/powerpc/platforms/powernv/idle.c | 10 ++++++++++
1 file changed, 10 insertions(+)

diff --git a/arch/powerpc/platforms/powernv/idle.c b/arch/powerpc/platforms/powernv/idle.c
index 19d94d021357..f2e2a6a4c274 100644
--- a/arch/powerpc/platforms/powernv/idle.c
+++ b/arch/powerpc/platforms/powernv/idle.c
@@ -600,6 +600,8 @@ struct p9_sprs {
u64 iamr;
u64 amor;
u64 uamor;
+ u64 dawr0;
+ u64 dawrx0;
};

static unsigned long power9_idle_stop(unsigned long psscr, bool mmu_on)
@@ -687,6 +689,10 @@ static unsigned long power9_idle_stop(unsigned long psscr, bool mmu_on)
sprs.iamr = mfspr(SPRN_IAMR);
sprs.amor = mfspr(SPRN_AMOR);
sprs.uamor = mfspr(SPRN_UAMOR);
+ if (cpu_has_feature(CPU_FTR_ARCH_31)) {
+ sprs.dawr0 = mfspr(SPRN_DAWR0);
+ sprs.dawrx0 = mfspr(SPRN_DAWRX0);
+ }

srr1 = isa300_idle_stop_mayloss(psscr); /* go idle */

@@ -710,6 +716,10 @@ static unsigned long power9_idle_stop(unsigned long psscr, bool mmu_on)
mtspr(SPRN_IAMR, sprs.iamr);
mtspr(SPRN_AMOR, sprs.amor);
mtspr(SPRN_UAMOR, sprs.uamor);
+ if (cpu_has_feature(CPU_FTR_ARCH_31)) {
+ mtspr(SPRN_DAWR0, sprs.dawr0);
+ mtspr(SPRN_DAWRX0, sprs.dawrx0);
+ }

/*
* Workaround for POWER9 DD2.0, if we lost resources, the ERAT
--
2.25.4
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