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powerpc/powernv: Add context management for Fast Sleep 

Before adding Fast-Sleep into the cpuidle framework, some low level
support needs to be added to enable it. This includes saving and
restoring of certain registers at entry and exit time of this state
respectively just like we do in the NAP idle state.

Signed-off-by: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
[Changelog modified by Preeti U. Murthy <preeti@linux.vnet.ibm.com>]
Signed-off-by: Preeti U. Murthy <preeti@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This commit is contained in:
Vaidyanathan Srinivasan 2014-02-26 05:38:25 +05:30 committed by Benjamin Herrenschmidt
parent 1b7839559b
commit aca79d2b6e
3 changed files with 53 additions and 21 deletions
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1
arch/powerpc/include/asm/processor.h
View File

@ -450,6 +450,7 @@ enum idle_boot_override {IDLE_NO_OVERRIDE = 0, IDLE_POWERSAVE_OFF};
extern int powersave_nap; /* set if nap mode can be used in idle loop */
extern void power7_nap(void);
extern void power7_sleep(void);
extern void flush_instruction_cache(void);
extern void hard_reset_now(void);
extern void poweroff_now(void);

10
arch/powerpc/kernel/exceptions-64s.S
View File

@ -121,9 +121,10 @@ BEGIN_FTR_SECTION
cmpwi cr1,r13,2
/* Total loss of HV state is fatal, we could try to use the
* PIR to locate a PACA, then use an emergency stack etc...
* but for now, let's just stay stuck here
* OPAL v3 based powernv platforms have new idle states
* which fall in this catagory.
*/
bgt cr1,.
bgt cr1,8f
GET_PACA(r13)
#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
@ -141,6 +142,11 @@ BEGIN_FTR_SECTION
beq cr1,2f
b .power7_wakeup_noloss
2: b .power7_wakeup_loss
/* Fast Sleep wakeup on PowerNV */
8: GET_PACA(r13)
b .power7_wakeup_loss
9:
END_FTR_SECTION_IFSET(CPU_FTR_HVMODE | CPU_FTR_ARCH_206)
#endif /* CONFIG_PPC_P7_NAP */

63
arch/powerpc/kernel/idle_power7.S
View File

@ -20,17 +20,27 @@
#undef DEBUG
/* Idle state entry routines */
#define IDLE_STATE_ENTER_SEQ(IDLE_INST) \
/* Magic NAP/SLEEP/WINKLE mode enter sequence */ \
std r0,0(r1); \
ptesync; \
ld r0,0(r1); \
1: cmp cr0,r0,r0; \
bne 1b; \
IDLE_INST; \
b .
.text
_GLOBAL(power7_idle)
/* Now check if user or arch enabled NAP mode */
LOAD_REG_ADDRBASE(r3,powersave_nap)
lwz r4,ADDROFF(powersave_nap)(r3)
cmpwi 0,r4,0
beqlr
/* fall through */
_GLOBAL(power7_nap)
/*
* Pass requested state in r3:
* 0 - nap
* 1 - sleep
*/
_GLOBAL(power7_powersave_common)
/* Use r3 to pass state nap/sleep/winkle */
/* NAP is a state loss, we create a regs frame on the
* stack, fill it up with the state we care about and
* stick a pointer to it in PACAR1. We really only
@ -79,8 +89,8 @@ _GLOBAL(power7_nap)
/* Continue saving state */
SAVE_GPR(2, r1)
SAVE_NVGPRS(r1)
mfcr r3
std r3,_CCR(r1)
mfcr r4
std r4,_CCR(r1)
std r9,_MSR(r1)
std r1,PACAR1(r13)
@ -90,15 +100,30 @@ _GLOBAL(power7_enter_nap_mode)
li r4,KVM_HWTHREAD_IN_NAP
stb r4,HSTATE_HWTHREAD_STATE(r13)
#endif
cmpwi cr0,r3,1
beq 2f
IDLE_STATE_ENTER_SEQ(PPC_NAP)
/* No return */
2: IDLE_STATE_ENTER_SEQ(PPC_SLEEP)
/* No return */
/* Magic NAP mode enter sequence */
std r0,0(r1)
ptesync
ld r0,0(r1)
1: cmp cr0,r0,r0
bne 1b
PPC_NAP
b .
_GLOBAL(power7_idle)
/* Now check if user or arch enabled NAP mode */
LOAD_REG_ADDRBASE(r3,powersave_nap)
lwz r4,ADDROFF(powersave_nap)(r3)
cmpwi 0,r4,0
beqlr
/* fall through */
_GLOBAL(power7_nap)
li r3,0
b power7_powersave_common
/* No return */
_GLOBAL(power7_sleep)
li r3,1
b power7_powersave_common
/* No return */
_GLOBAL(power7_wakeup_loss)
ld r1,PACAR1(r13)