| Message ID | 1421654727-31656-1-git-send-email-shreyas@linux.vnet.ibm.com (mailing list archive) |
|---|---|
| State | Rejected |
| Delegated to: | Michael Ellerman |
| Headers | show |
On Mon, 2015-01-19 at 13:35 +0530, Shreyas B. Prabhu wrote: > PECE1 bit in LPCR is used to control whether decrementer can cause exit > from powersaving states. PECE1 bit is cleared before entering fastsleep > or deeper powersaving state and it is set on waking up. Since both > cpuidle and cpu offline operations use these powersaving states, add > helper functions to be used in both these places. Thanks. That isn't really much clearer than the original, so in the end I just merged your original fix. I'll think if there's a bigger consolidation we can do that makes it clearer. cheers
On Friday 23 January 2015 08:36 AM, Michael Ellerman wrote: > On Mon, 2015-01-19 at 13:35 +0530, Shreyas B. Prabhu wrote: >> PECE1 bit in LPCR is used to control whether decrementer can cause exit >> from powersaving states. PECE1 bit is cleared before entering fastsleep >> or deeper powersaving state and it is set on waking up. Since both >> cpuidle and cpu offline operations use these powersaving states, add >> helper functions to be used in both these places. > > Thanks. > > That isn't really much clearer than the original, so in the end I just merged > your original fix. > > I'll think if there's a bigger consolidation we can do that makes it clearer. > > cheers > > Helper could have been this : #define LPCR_CLEAR_PECE1 (mfspr(SPRN_LPCR) & ~(u64)LPCR_PECE1) This perhaps would make it more clearer, but it will end up using additional mfspr here- static int fastsleep_loop(struct cpuidle_device *dev, struct cpuidle_driver *drv, int index) { ... new_lpcr = old_lpcr; /* Do not exit powersave upon decrementer as we've setup the timer * offload. */ new_lpcr &= ~LPCR_PECE1; mtspr(SPRN_LPCR, new_lpcr);
On Fri, 2015-01-23 at 09:16 +0530, Shreyas B Prabhu wrote: > > On Friday 23 January 2015 08:36 AM, Michael Ellerman wrote: > > On Mon, 2015-01-19 at 13:35 +0530, Shreyas B. Prabhu wrote: > >> PECE1 bit in LPCR is used to control whether decrementer can cause exit > >> from powersaving states. PECE1 bit is cleared before entering fastsleep > >> or deeper powersaving state and it is set on waking up. Since both > >> cpuidle and cpu offline operations use these powersaving states, add > >> helper functions to be used in both these places. > > > > Thanks. > > > > That isn't really much clearer than the original, so in the end I just merged > > your original fix. > > > > I'll think if there's a bigger consolidation we can do that makes it clearer. > > Helper could have been this : > > #define LPCR_CLEAR_PECE1 (mfspr(SPRN_LPCR) & ~(u64)LPCR_PECE1) > > This perhaps would make it more clearer, but it will end up using additional mfspr here- Yeah. Maybe we just leave it open coded, I'll have a think about it. cheers
diff --git a/arch/powerpc/include/asm/reg.h b/arch/powerpc/include/asm/reg.h index c870e38..0847303 100644 --- a/arch/powerpc/include/asm/reg.h +++ b/arch/powerpc/include/asm/reg.h @@ -339,6 +339,10 @@ #define LPCR_LPES_SH 2 #define LPCR_RMI 0x00000002 /* real mode is cache inhibit */ #define LPCR_HDICE 0x00000001 /* Hyp Decr enable (HV,PR,EE) */ +/* LPCR PECE1 helpers. Used to disable/enable wake up due to decrementer */ +#define LPCR_CLEAR_PECE1(old) (old & ~(u64)LPCR_PECE1) +#define LPCR_SET_PECE1(old) (old | (u64)LPCR_PECE1) + #ifndef SPRN_LPID #define SPRN_LPID 0x13F /* Logical Partition Identifier */ #endif diff --git a/arch/powerpc/platforms/powernv/smp.c b/arch/powerpc/platforms/powernv/smp.c index 781ec45..ab61cb0 100644 --- a/arch/powerpc/platforms/powernv/smp.c +++ b/arch/powerpc/platforms/powernv/smp.c @@ -165,7 +165,7 @@ static void pnv_smp_cpu_kill_self(void) /* We don't want to take decrementer interrupts while we are offline, * so clear LPCR:PECE1. We keep PECE2 enabled. */ - mtspr(SPRN_LPCR, mfspr(SPRN_LPCR) & ~(u64)LPCR_PECE1); + mtspr(SPRN_LPCR, LPCR_CLEAR_PECE1(mfspr(SPRN_LPCR))); while (!generic_check_cpu_restart(cpu)) { ppc64_runlatch_off(); @@ -203,7 +203,7 @@ static void pnv_smp_cpu_kill_self(void) if (!generic_check_cpu_restart(cpu)) DBG("CPU%d Unexpected exit while offline !\n", cpu); } - mtspr(SPRN_LPCR, mfspr(SPRN_LPCR) | LPCR_PECE1); + mtspr(SPRN_LPCR, LPCR_SET_PECE1(mfspr(SPRN_LPCR))); DBG("CPU%d coming online...\n", cpu); } diff --git a/drivers/cpuidle/cpuidle-powernv.c b/drivers/cpuidle/cpuidle-powernv.c index de61b9a..ed0be4c 100644 --- a/drivers/cpuidle/cpuidle-powernv.c +++ b/drivers/cpuidle/cpuidle-powernv.c @@ -69,11 +69,10 @@ static int fastsleep_loop(struct cpuidle_device *dev, if (unlikely(system_state < SYSTEM_RUNNING)) return index; - new_lpcr = old_lpcr; /* Do not exit powersave upon decrementer as we've setup the timer * offload. */ - new_lpcr &= ~LPCR_PECE1; + new_lpcr = LPCR_CLEAR_PECE1(old_lpcr); mtspr(SPRN_LPCR, new_lpcr); power7_sleep();
PECE1 bit in LPCR is used to control whether decrementer can cause exit from powersaving states. PECE1 bit is cleared before entering fastsleep or deeper powersaving state and it is set on waking up. Since both cpuidle and cpu offline operations use these powersaving states, add helper functions to be used in both these places. Signed-off-by: Shreyas B. Prabhu <shreyas@linux.vnet.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: linuxppc-dev@lists.ozlabs.org --- arch/powerpc/include/asm/reg.h | 4 ++++ arch/powerpc/platforms/powernv/smp.c | 4 ++-- drivers/cpuidle/cpuidle-powernv.c | 3 +-- 3 files changed, 7 insertions(+), 4 deletions(-)