linux/arch/powerpc/kernel/idle_power7.S
Vaidyanathan Srinivasan 97eb001f03 powerpc/powernv: Add OPAL call to resync timebase on wakeup
During "Fast-sleep" and deeper power savings state, decrementer and
timebase could be stopped making it out of sync with rest
of the cores in the system.

Add a firmware call to request platform to resync timebase
using low level platform methods.

Signed-off-by: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
Signed-off-by: Preeti U. Murthy <preeti@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-03-05 15:56:54 +11:00

179 lines
3.7 KiB
ArmAsm

/*
* This file contains the power_save function for Power7 CPUs.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/threads.h>
#include <asm/processor.h>
#include <asm/page.h>
#include <asm/cputable.h>
#include <asm/thread_info.h>
#include <asm/ppc_asm.h>
#include <asm/asm-offsets.h>
#include <asm/ppc-opcode.h>
#include <asm/hw_irq.h>
#include <asm/kvm_book3s_asm.h>
#include <asm/opal.h>
#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
/*
* 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
* need to save PC, some CR bits and the NV GPRs,
* but for now an interrupt frame will do.
*/
mflr r0
std r0,16(r1)
stdu r1,-INT_FRAME_SIZE(r1)
std r0,_LINK(r1)
std r0,_NIP(r1)
#ifndef CONFIG_SMP
/* Make sure FPU, VSX etc... are flushed as we may lose
* state when going to nap mode
*/
bl .discard_lazy_cpu_state
#endif /* CONFIG_SMP */
/* Hard disable interrupts */
mfmsr r9
rldicl r9,r9,48,1
rotldi r9,r9,16
mtmsrd r9,1 /* hard-disable interrupts */
/* Check if something happened while soft-disabled */
lbz r0,PACAIRQHAPPENED(r13)
cmpwi cr0,r0,0
beq 1f
addi r1,r1,INT_FRAME_SIZE
ld r0,16(r1)
mtlr r0
blr
1: /* We mark irqs hard disabled as this is the state we'll
* be in when returning and we need to tell arch_local_irq_restore()
* about it
*/
li r0,PACA_IRQ_HARD_DIS
stb r0,PACAIRQHAPPENED(r13)
/* We haven't lost state ... yet */
li r0,0
stb r0,PACA_NAPSTATELOST(r13)
/* Continue saving state */
SAVE_GPR(2, r1)
SAVE_NVGPRS(r1)
mfcr r4
std r4,_CCR(r1)
std r9,_MSR(r1)
std r1,PACAR1(r13)
_GLOBAL(power7_enter_nap_mode)
#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
/* Tell KVM we're napping */
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 */
_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_tb_loss)
ld r2,PACATOC(r13);
ld r1,PACAR1(r13)
/* Time base re-sync */
li r0,OPAL_RESYNC_TIMEBASE
LOAD_REG_ADDR(r11,opal);
ld r12,8(r11);
ld r2,0(r11);
mtctr r12
bctrl
/* TODO: Check r3 for failure */
REST_NVGPRS(r1)
REST_GPR(2, r1)
ld r3,_CCR(r1)
ld r4,_MSR(r1)
ld r5,_NIP(r1)
addi r1,r1,INT_FRAME_SIZE
mtcr r3
mfspr r3,SPRN_SRR1 /* Return SRR1 */
mtspr SPRN_SRR1,r4
mtspr SPRN_SRR0,r5
rfid
_GLOBAL(power7_wakeup_loss)
ld r1,PACAR1(r13)
REST_NVGPRS(r1)
REST_GPR(2, r1)
ld r3,_CCR(r1)
ld r4,_MSR(r1)
ld r5,_NIP(r1)
addi r1,r1,INT_FRAME_SIZE
mtcr r3
mtspr SPRN_SRR1,r4
mtspr SPRN_SRR0,r5
rfid
_GLOBAL(power7_wakeup_noloss)
lbz r0,PACA_NAPSTATELOST(r13)
cmpwi r0,0
bne .power7_wakeup_loss
ld r1,PACAR1(r13)
ld r4,_MSR(r1)
ld r5,_NIP(r1)
addi r1,r1,INT_FRAME_SIZE
mtspr SPRN_SRR1,r4
mtspr SPRN_SRR0,r5
rfid