// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * PowerNV cpuidle code
 *
 * Copyright 2015 IBM Corp.
 */

#include <linux/types.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/of.h>
#include <linux/device.h>
#include <linux/cpu.h>

#include <asm/firmware.h>
#include <asm/interrupt.h>
#include <asm/machdep.h>
#include <asm/opal.h>
#include <asm/cputhreads.h>
#include <asm/cpuidle.h>
#include <asm/text-patching.h>
#include <asm/smp.h>
#include <asm/runlatch.h>
#include <asm/dbell.h>

#include "powernv.h"
#include "subcore.h"

/* Power ISA 3.0 allows for stop states 0x0 - 0xF */
#define MAX_STOP_STATE  0xF

#define P9_STOP_SPR_MSR 2000
#define P9_STOP_SPR_PSSCR      855

static u32 supported_cpuidle_states;
struct pnv_idle_states_t *pnv_idle_states;
int nr_pnv_idle_states;

/*
 * The default stop state that will be used by ppc_md.power_save
 * function on platforms that support stop instruction.
 */
static u64 pnv_default_stop_val;
static u64 pnv_default_stop_mask;
static bool default_stop_found;

/*
 * First stop state levels when SPR and TB loss can occur.
 */
static u64 pnv_first_tb_loss_level = MAX_STOP_STATE + 1;
static u64 deep_spr_loss_state = MAX_STOP_STATE + 1;

/*
 * psscr value and mask of the deepest stop idle state.
 * Used when a cpu is offlined.
 */
static u64 pnv_deepest_stop_psscr_val;
static u64 pnv_deepest_stop_psscr_mask;
static u64 pnv_deepest_stop_flag;
static bool deepest_stop_found;

static unsigned long power7_offline_type;

static int __init pnv_save_sprs_for_deep_states(void)
{
        int cpu;
        int rc;

        /*
         * hid0, hid1, hid4, hid5, hmeer and lpcr values are symmetric across
         * all cpus at boot. Get these reg values of current cpu and use the
         * same across all cpus.
         */
        uint64_t lpcr_val       = mfspr(SPRN_LPCR);
        uint64_t hid0_val       = mfspr(SPRN_HID0);
        uint64_t hmeer_val      = mfspr(SPRN_HMEER);
        uint64_t msr_val = MSR_IDLE;
        uint64_t psscr_val = pnv_deepest_stop_psscr_val;

        for_each_present_cpu(cpu) {
                uint64_t pir = get_hard_smp_processor_id(cpu);
                uint64_t hsprg0_val = (uint64_t)paca_ptrs[cpu];

                rc = opal_slw_set_reg(pir, SPRN_HSPRG0, hsprg0_val);
                if (rc != 0)
                        return rc;

                rc = opal_slw_set_reg(pir, SPRN_LPCR, lpcr_val);
                if (rc != 0)
                        return rc;

                if (cpu_has_feature(CPU_FTR_ARCH_300)) {
                        rc = opal_slw_set_reg(pir, P9_STOP_SPR_MSR, msr_val);
                        if (rc)
                                return rc;

                        rc = opal_slw_set_reg(pir,
                                              P9_STOP_SPR_PSSCR, psscr_val);

                        if (rc)
                                return rc;
                }

                /* HIDs are per core registers */
                if (cpu_thread_in_core(cpu) == 0) {

                        rc = opal_slw_set_reg(pir, SPRN_HMEER, hmeer_val);
                        if (rc != 0)
                                return rc;

                        rc = opal_slw_set_reg(pir, SPRN_HID0, hid0_val);
                        if (rc != 0)
                                return rc;

                        /* Only p8 needs to set extra HID registers */
                        if (!cpu_has_feature(CPU_FTR_ARCH_300)) {
                                uint64_t hid1_val = mfspr(SPRN_HID1);
                                uint64_t hid4_val = mfspr(SPRN_HID4);
                                uint64_t hid5_val = mfspr(SPRN_HID5);

                                rc = opal_slw_set_reg(pir, SPRN_HID1, hid1_val);
                                if (rc != 0)
                                        return rc;

                                rc = opal_slw_set_reg(pir, SPRN_HID4, hid4_val);
                                if (rc != 0)
                                        return rc;

                                rc = opal_slw_set_reg(pir, SPRN_HID5, hid5_val);
                                if (rc != 0)
                                        return rc;
                        }
                }
        }

        return 0;
}

u32 pnv_get_supported_cpuidle_states(void)
{
        return supported_cpuidle_states;
}
EXPORT_SYMBOL_GPL(pnv_get_supported_cpuidle_states);

static void pnv_fastsleep_workaround_apply(void *info)

{
        int cpu = smp_processor_id();
        int rc;
        int *err = info;

        if (cpu_first_thread_sibling(cpu) != cpu)
                return;

        rc = opal_config_cpu_idle_state(OPAL_CONFIG_IDLE_FASTSLEEP,
                                        OPAL_CONFIG_IDLE_APPLY);
        if (rc)
                *err = 1;
}

static bool power7_fastsleep_workaround_entry = true;
static bool power7_fastsleep_workaround_exit = true;

/*
 * Used to store fastsleep workaround state
 * 0 - Workaround applied/undone at fastsleep entry/exit path (Default)
 * 1 - Workaround applied once, never undone.
 */
static u8 fastsleep_workaround_applyonce;

static ssize_t show_fastsleep_workaround_applyonce(struct device *dev,
                struct device_attribute *attr, char *buf)
{
        return sprintf(buf, "%u\n", fastsleep_workaround_applyonce);
}

static ssize_t store_fastsleep_workaround_applyonce(struct device *dev,
                struct device_attribute *attr, const char *buf,
                size_t count)
{
        int err;
        u8 val;

        if (kstrtou8(buf, 0, &val) || val != 1)
                return -EINVAL;

        if (fastsleep_workaround_applyonce == 1)
                return count;

        /*
         * fastsleep_workaround_applyonce = 1 implies
         * fastsleep workaround needs to be left in 'applied' state on all
         * the cores. Do this by-
         * 1. Disable the 'undo' workaround in fastsleep exit path
         * 2. Sendi IPIs to all the cores which have at least one online thread
         * 3. Disable the 'apply' workaround in fastsleep entry path
         *
         * There is no need to send ipi to cores which have all threads
         * offlined, as last thread of the core entering fastsleep or deeper
         * state would have applied workaround.
         */
        power7_fastsleep_workaround_exit = false;

        cpus_read_lock();
        on_each_cpu(pnv_fastsleep_workaround_apply, &err, 1);
        cpus_read_unlock();
        if (err) {
                pr_err("fastsleep_workaround_applyonce change failed while running pnv_fastsleep_workaround_apply");
                goto fail;
        }

        power7_fastsleep_workaround_entry = false;

        fastsleep_workaround_applyonce = 1;

        return count;
fail:
        return -EIO;
}

static DEVICE_ATTR(fastsleep_workaround_applyonce, 0600,
                        show_fastsleep_workaround_applyonce,
                        store_fastsleep_workaround_applyonce);

static inline void atomic_start_thread_idle(void)
{
        int cpu = raw_smp_processor_id();
        int first = cpu_first_thread_sibling(cpu);
        int thread_nr = cpu_thread_in_core(cpu);
        unsigned long *state = &paca_ptrs[first]->idle_state;

        clear_bit(thread_nr, state);
}

static inline void atomic_stop_thread_idle(void)
{
        int cpu = raw_smp_processor_id();
        int first = cpu_first_thread_sibling(cpu);
        int thread_nr = cpu_thread_in_core(cpu);
        unsigned long *state = &paca_ptrs[first]->idle_state;

        set_bit(thread_nr, state);
}

static inline void atomic_lock_thread_idle(void)
{
        int cpu = raw_smp_processor_id();
        int first = cpu_first_thread_sibling(cpu);
        unsigned long *lock = &paca_ptrs[first]->idle_lock;

        while (unlikely(test_and_set_bit_lock(NR_PNV_CORE_IDLE_LOCK_BIT, lock)))
                barrier();
}

static inline void atomic_unlock_and_stop_thread_idle(void)
{
        int cpu = raw_smp_processor_id();
        int first = cpu_first_thread_sibling(cpu);
        unsigned long thread = 1UL << cpu_thread_in_core(cpu);
        unsigned long *state = &paca_ptrs[first]->idle_state;
        unsigned long *lock = &paca_ptrs[first]->idle_lock;
        u64 s = READ_ONCE(*state);
        u64 new, tmp;

        BUG_ON(!(READ_ONCE(*lock) & PNV_CORE_IDLE_LOCK_BIT));
        BUG_ON(s & thread);

again:
        new = s | thread;
        tmp = cmpxchg(state, s, new);
        if (unlikely(tmp != s)) {
                s = tmp;
                goto again;
        }
        clear_bit_unlock(NR_PNV_CORE_IDLE_LOCK_BIT, lock);
}

static inline void atomic_unlock_thread_idle(void)
{
        int cpu = raw_smp_processor_id();
        int first = cpu_first_thread_sibling(cpu);
        unsigned long *lock = &paca_ptrs[first]->idle_lock;

        BUG_ON(!test_bit(NR_PNV_CORE_IDLE_LOCK_BIT, lock));
        clear_bit_unlock(NR_PNV_CORE_IDLE_LOCK_BIT, lock);
}

/* P7 and P8 */
struct p7_sprs {
        /* per core */
        u64 tscr;
        u64 worc;

        /* per subcore */
        u64 sdr1;
        u64 rpr;

        /* per thread */
        u64 lpcr;
        u64 hfscr;
        u64 fscr;
        u64 purr;
        u64 spurr;
        u64 dscr;
        u64 wort;

        /* per thread SPRs that get lost in shallow states */
        u64 amr;
        u64 iamr;
        u64 uamor;
        /* amor is restored to constant ~0 */
};

static unsigned long power7_idle_insn(unsigned long type)
{
        int cpu = raw_smp_processor_id();
        int first = cpu_first_thread_sibling(cpu);
        unsigned long *state = &paca_ptrs[first]->idle_state;
        unsigned long thread = 1UL << cpu_thread_in_core(cpu);
        unsigned long core_thread_mask = (1UL << threads_per_core) - 1;
        unsigned long srr1;
        bool full_winkle;
        struct p7_sprs sprs = {}; /* avoid false use-uninitialised */
        bool sprs_saved = false;
        int rc;

        if (unlikely(type != PNV_THREAD_NAP)) {
                atomic_lock_thread_idle();

                BUG_ON(!(*state & thread));
                *state &= ~thread;

                if (power7_fastsleep_workaround_entry) {
                        if ((*state & core_thread_mask) == 0) {
                                rc = opal_config_cpu_idle_state(
                                                OPAL_CONFIG_IDLE_FASTSLEEP,
                                                OPAL_CONFIG_IDLE_APPLY);
                                BUG_ON(rc);
                        }
                }

                if (type == PNV_THREAD_WINKLE) {
                        sprs.tscr       = mfspr(SPRN_TSCR);
                        sprs.worc       = mfspr(SPRN_WORC);

                        sprs.sdr1       = mfspr(SPRN_SDR1);
                        sprs.rpr        = mfspr(SPRN_RPR);

                        sprs.lpcr       = mfspr(SPRN_LPCR);
                        if (cpu_has_feature(CPU_FTR_ARCH_207S)) {
                                sprs.hfscr      = mfspr(SPRN_HFSCR);
                                sprs.fscr       = mfspr(SPRN_FSCR);
                        }
                        sprs.purr       = mfspr(SPRN_PURR);
                        sprs.spurr      = mfspr(SPRN_SPURR);
                        sprs.dscr       = mfspr(SPRN_DSCR);
                        sprs.wort       = mfspr(SPRN_WORT);

                        sprs_saved = true;

                        /*
                         * Increment winkle counter and set all winkle bits if
                         * all threads are winkling. This allows wakeup side to
                         * distinguish between fast sleep and winkle state
                         * loss. Fast sleep still has to resync the timebase so
                         * this may not be a really big win.
                         */
                        *state += 1 << PNV_CORE_IDLE_WINKLE_COUNT_SHIFT;
                        if ((*state & PNV_CORE_IDLE_WINKLE_COUNT_BITS)
                                        >> PNV_CORE_IDLE_WINKLE_COUNT_SHIFT
                                        == threads_per_core)
                                *state |= PNV_CORE_IDLE_THREAD_WINKLE_BITS;
                        WARN_ON((*state & PNV_CORE_IDLE_WINKLE_COUNT_BITS) == 0);
                }

                atomic_unlock_thread_idle();
        }

        if (cpu_has_feature(CPU_FTR_ARCH_207S)) {
                sprs.amr        = mfspr(SPRN_AMR);
                sprs.iamr       = mfspr(SPRN_IAMR);
                sprs.uamor      = mfspr(SPRN_UAMOR);
        }

        local_paca->thread_idle_state = type;
        srr1 = isa206_idle_insn_mayloss(type);          /* go idle */
        local_paca->thread_idle_state = PNV_THREAD_RUNNING;

        WARN_ON_ONCE(!srr1);
        WARN_ON_ONCE(mfmsr() & (MSR_IR|MSR_DR));

        if (cpu_has_feature(CPU_FTR_ARCH_207S)) {
                if ((srr1 & SRR1_WAKESTATE) != SRR1_WS_NOLOSS) {
                        /*
                         * We don't need an isync after the mtsprs here because
                         * the upcoming mtmsrd is execution synchronizing.
                         */
                        mtspr(SPRN_AMR,         sprs.amr);
                        mtspr(SPRN_IAMR,        sprs.iamr);
                        mtspr(SPRN_AMOR,        ~0);
                        mtspr(SPRN_UAMOR,       sprs.uamor);
                }
        }

        if (unlikely((srr1 & SRR1_WAKEMASK_P8) == SRR1_WAKEHMI))
                hmi_exception_realmode(NULL);

        if (likely((srr1 & SRR1_WAKESTATE) != SRR1_WS_HVLOSS)) {
                if (unlikely(type != PNV_THREAD_NAP)) {
                        atomic_lock_thread_idle();
                        if (type == PNV_THREAD_WINKLE) {
                                WARN_ON((*state & PNV_CORE_IDLE_WINKLE_COUNT_BITS) == 0);
                                *state -= 1 << PNV_CORE_IDLE_WINKLE_COUNT_SHIFT;
                                *state &= ~(thread << PNV_CORE_IDLE_THREAD_WINKLE_BITS_SHIFT);
                        }
                        atomic_unlock_and_stop_thread_idle();
                }
                return srr1;
        }

        /* HV state loss */
        BUG_ON(type == PNV_THREAD_NAP);

        atomic_lock_thread_idle();

        full_winkle = false;
        if (type == PNV_THREAD_WINKLE) {
                WARN_ON((*state & PNV_CORE_IDLE_WINKLE_COUNT_BITS) == 0);
                *state -= 1 << PNV_CORE_IDLE_WINKLE_COUNT_SHIFT;
                if (*state & (thread << PNV_CORE_IDLE_THREAD_WINKLE_BITS_SHIFT)) {
                        *state &= ~(thread << PNV_CORE_IDLE_THREAD_WINKLE_BITS_SHIFT);
                        full_winkle = true;
                        BUG_ON(!sprs_saved);
                }
        }

        WARN_ON(*state & thread);

        if ((*state & core_thread_mask) != 0)
                goto core_woken;

        /* Per-core SPRs */
        if (full_winkle) {
                mtspr(SPRN_TSCR,        sprs.tscr);
                mtspr(SPRN_WORC,        sprs.worc);
        }

        if (power7_fastsleep_workaround_exit) {
                rc = opal_config_cpu_idle_state(OPAL_CONFIG_IDLE_FASTSLEEP,
                                                OPAL_CONFIG_IDLE_UNDO);
                BUG_ON(rc);
        }

        /* TB */
        if (opal_resync_timebase() != OPAL_SUCCESS)
                BUG();

core_woken:
        if (!full_winkle)
                goto subcore_woken;

        if ((*state & local_paca->subcore_sibling_mask) != 0)
                goto subcore_woken;

        /* Per-subcore SPRs */
        mtspr(SPRN_SDR1,        sprs.sdr1);
        mtspr(SPRN_RPR,         sprs.rpr);

subcore_woken:
        /*
         * isync after restoring shared SPRs and before unlocking. Unlock
         * only contains hwsync which does not necessarily do the right
         * thing for SPRs.
         */
        isync();
        atomic_unlock_and_stop_thread_idle();

        /* Fast sleep does not lose SPRs */
        if (!full_winkle)
                return srr1;

        /* Per-thread SPRs */
        mtspr(SPRN_LPCR,        sprs.lpcr);
        if (cpu_has_feature(CPU_FTR_ARCH_207S)) {
                mtspr(SPRN_HFSCR,       sprs.hfscr);
                mtspr(SPRN_FSCR,        sprs.fscr);
        }
        mtspr(SPRN_PURR,        sprs.purr);
        mtspr(SPRN_SPURR,       sprs.spurr);
        mtspr(SPRN_DSCR,        sprs.dscr);
        mtspr(SPRN_WORT,        sprs.wort);

        mtspr(SPRN_SPRG3,       local_paca->sprg_vdso);

#ifdef CONFIG_PPC_64S_HASH_MMU
        /*
         * The SLB has to be restored here, but it sometimes still
         * contains entries, so the __ variant must be used to prevent
         * multi hits.
         */
        __slb_restore_bolted_realmode();
#endif

        return srr1;
}

extern unsigned long idle_kvm_start_guest(unsigned long srr1);

#ifdef CONFIG_HOTPLUG_CPU
static unsigned long power7_offline(void)
{
        unsigned long srr1;

        mtmsr(MSR_IDLE);

#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
        /* Tell KVM we're entering idle. */
        /******************************************************/
        /*  N O T E   W E L L    ! ! !    N O T E   W E L L   */
        /* The following store to HSTATE_HWTHREAD_STATE(r13)  */
        /* MUST occur in real mode, i.e. with the MMU off,    */
        /* and the MMU must stay off until we clear this flag */
        /* and test HSTATE_HWTHREAD_REQ(r13) in               */
        /* pnv_powersave_wakeup in this file.                 */
        /* The reason is that another thread can switch the   */
        /* MMU to a guest context whenever this flag is set   */
        /* to KVM_HWTHREAD_IN_IDLE, and if the MMU was on,    */
        /* that would potentially cause this thread to start  */
        /* executing instructions from guest memory in        */
        /* hypervisor mode, leading to a host crash or data   */
        /* corruption, or worse.                              */
        /******************************************************/
        local_paca->kvm_hstate.hwthread_state = KVM_HWTHREAD_IN_IDLE;
#endif

        __ppc64_runlatch_off();
        srr1 = power7_idle_insn(power7_offline_type);
        __ppc64_runlatch_on();

#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
        local_paca->kvm_hstate.hwthread_state = KVM_HWTHREAD_IN_KERNEL;
        /* Order setting hwthread_state vs. testing hwthread_req */
        smp_mb();
        if (local_paca->kvm_hstate.hwthread_req)
                srr1 = idle_kvm_start_guest(srr1);
#endif

        mtmsr(MSR_KERNEL);

        return srr1;
}
#endif

void power7_idle_type(unsigned long type)
{
        unsigned long srr1;

        if (!prep_irq_for_idle_irqsoff())
                return;

        mtmsr(MSR_IDLE);
        __ppc64_runlatch_off();
        srr1 = power7_idle_insn(type);
        __ppc64_runlatch_on();
        mtmsr(MSR_KERNEL);

        fini_irq_for_idle_irqsoff();
        irq_set_pending_from_srr1(srr1);
}

static void power7_idle(void)
{
        if (!powersave_nap)
                return;

        power7_idle_type(PNV_THREAD_NAP);
}

struct p9_sprs {
        /* per core */
        u64 ptcr;
        u64 rpr;
        u64 tscr;
        u64 ldbar;

        /* per thread */
        u64 lpcr;
        u64 hfscr;
        u64 fscr;
        u64 pid;
        u64 purr;
        u64 spurr;
        u64 dscr;
        u64 ciabr;

        u64 mmcra;
        u32 mmcr0;
        u32 mmcr1;
        u64 mmcr2;

        /* per thread SPRs that get lost in shallow states */
        u64 amr;
        u64 iamr;
        u64 amor;
        u64 uamor;
};

static unsigned long power9_idle_stop(unsigned long psscr)
{
        int cpu = raw_smp_processor_id();
        int first = cpu_first_thread_sibling(cpu);
        unsigned long *state = &paca_ptrs[first]->idle_state;
        unsigned long core_thread_mask = (1UL << threads_per_core) - 1;
        unsigned long srr1;
        unsigned long pls;
        unsigned long mmcr0 = 0;
        unsigned long mmcra = 0;
        struct p9_sprs sprs = {}; /* avoid false used-uninitialised */
        bool sprs_saved = false;

        if (!(psscr & (PSSCR_EC|PSSCR_ESL))) {
                /* EC=ESL=0 case */

                /*
                 * Wake synchronously. SRESET via xscom may still cause
                 * a 0x100 powersave wakeup with SRR1 reason!
                 */
                srr1 = isa300_idle_stop_noloss(psscr);          /* go idle */
                if (likely(!srr1))
                        return 0;

                /*
                 * Registers not saved, can't recover!
                 * This would be a hardware bug
                 */
                BUG_ON((srr1 & SRR1_WAKESTATE) != SRR1_WS_NOLOSS);

                goto out;
        }

        /* EC=ESL=1 case */
#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
        if (cpu_has_feature(CPU_FTR_P9_TM_XER_SO_BUG)) {
                local_paca->requested_psscr = psscr;
                /* order setting requested_psscr vs testing dont_stop */
                smp_mb();
                if (atomic_read(&local_paca->dont_stop)) {
                        local_paca->requested_psscr = 0;
                        return 0;
                }
        }
#endif

        if (!cpu_has_feature(CPU_FTR_POWER9_DD2_1)) {
                 /*
                  * POWER9 DD2 can incorrectly set PMAO when waking up
                  * after a state-loss idle. Saving and restoring MMCR0
                  * over idle is a workaround.
                  */
                mmcr0           = mfspr(SPRN_MMCR0);
        }

        if ((psscr & PSSCR_RL_MASK) >= deep_spr_loss_state) {
                sprs.lpcr       = mfspr(SPRN_LPCR);
                sprs.hfscr      = mfspr(SPRN_HFSCR);
                sprs.fscr       = mfspr(SPRN_FSCR);
                sprs.pid        = mfspr(SPRN_PID);
                sprs.purr       = mfspr(SPRN_PURR);
                sprs.spurr      = mfspr(SPRN_SPURR);
                sprs.dscr       = mfspr(SPRN_DSCR);
                sprs.ciabr      = mfspr(SPRN_CIABR);

                sprs.mmcra      = mfspr(SPRN_MMCRA);
                sprs.mmcr0      = mfspr(SPRN_MMCR0);
                sprs.mmcr1      = mfspr(SPRN_MMCR1);
                sprs.mmcr2      = mfspr(SPRN_MMCR2);

                sprs.ptcr       = mfspr(SPRN_PTCR);
                sprs.rpr        = mfspr(SPRN_RPR);
                sprs.tscr       = mfspr(SPRN_TSCR);
                if (!firmware_has_feature(FW_FEATURE_ULTRAVISOR))
                        sprs.ldbar = mfspr(SPRN_LDBAR);

                sprs_saved = true;

                atomic_start_thread_idle();
        }

        sprs.amr        = mfspr(SPRN_AMR);
        sprs.iamr       = mfspr(SPRN_IAMR);
        sprs.uamor      = mfspr(SPRN_UAMOR);

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

#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
        local_paca->requested_psscr = 0;
#endif

        psscr = mfspr(SPRN_PSSCR);

        WARN_ON_ONCE(!srr1);
        WARN_ON_ONCE(mfmsr() & (MSR_IR|MSR_DR));

        if ((srr1 & SRR1_WAKESTATE) != SRR1_WS_NOLOSS) {
                /*
                 * We don't need an isync after the mtsprs here because the
                 * upcoming mtmsrd is execution synchronizing.
                 */
                mtspr(SPRN_AMR,         sprs.amr);
                mtspr(SPRN_IAMR,        sprs.iamr);
                mtspr(SPRN_AMOR,        ~0);
                mtspr(SPRN_UAMOR,       sprs.uamor);

                /*
                 * Workaround for POWER9 DD2.0, if we lost resources, the ERAT
                 * might have been corrupted and needs flushing. We also need
                 * to reload MMCR0 (see mmcr0 comment above).
                 */
                if (!cpu_has_feature(CPU_FTR_POWER9_DD2_1)) {
                        asm volatile(PPC_ISA_3_0_INVALIDATE_ERAT);
                        mtspr(SPRN_MMCR0, mmcr0);
                }

                /*
                 * DD2.2 and earlier need to set then clear bit 60 in MMCRA
                 * to ensure the PMU starts running.
                 */
                mmcra = mfspr(SPRN_MMCRA);
                mmcra |= PPC_BIT(60);
                mtspr(SPRN_MMCRA, mmcra);
                mmcra &= ~PPC_BIT(60);
                mtspr(SPRN_MMCRA, mmcra);
        }

        if (unlikely((srr1 & SRR1_WAKEMASK_P8) == SRR1_WAKEHMI))
                hmi_exception_realmode(NULL);

        /*
         * On POWER9, SRR1 bits do not match exactly as expected.
         * SRR1_WS_GPRLOSS (10b) can also result in SPR loss, so
         * just always test PSSCR for SPR/TB state loss.
         */
        pls = (psscr & PSSCR_PLS) >> PSSCR_PLS_SHIFT;
        if (likely(pls < deep_spr_loss_state)) {
                if (sprs_saved)
                        atomic_stop_thread_idle();
                goto out;
        }

        /* HV state loss */
        BUG_ON(!sprs_saved);

        atomic_lock_thread_idle();

        if ((*state & core_thread_mask) != 0)
                goto core_woken;

        /* Per-core SPRs */
        mtspr(SPRN_PTCR,        sprs.ptcr);
        mtspr(SPRN_RPR,         sprs.rpr);
        mtspr(SPRN_TSCR,        sprs.tscr);

        if (pls >= pnv_first_tb_loss_level) {
                /* TB loss */
                if (opal_resync_timebase() != OPAL_SUCCESS)
                        BUG();
        }

        /*
         * isync after restoring shared SPRs and before unlocking. Unlock
         * only contains hwsync which does not necessarily do the right
         * thing for SPRs.
         */
        isync();

core_woken:
        atomic_unlock_and_stop_thread_idle();

        /* Per-thread SPRs */
        mtspr(SPRN_LPCR,        sprs.lpcr);
        mtspr(SPRN_HFSCR,       sprs.hfscr);
        mtspr(SPRN_FSCR,        sprs.fscr);
        mtspr(SPRN_PID,         sprs.pid);
        mtspr(SPRN_PURR,        sprs.purr);
        mtspr(SPRN_SPURR,       sprs.spurr);
        mtspr(SPRN_DSCR,        sprs.dscr);
        mtspr(SPRN_CIABR,       sprs.ciabr);

        mtspr(SPRN_MMCRA,       sprs.mmcra);
        mtspr(SPRN_MMCR0,       sprs.mmcr0);
        mtspr(SPRN_MMCR1,       sprs.mmcr1);
        mtspr(SPRN_MMCR2,       sprs.mmcr2);
        if (!firmware_has_feature(FW_FEATURE_ULTRAVISOR))
                mtspr(SPRN_LDBAR, sprs.ldbar);

        mtspr(SPRN_SPRG3,       local_paca->sprg_vdso);

        if (!radix_enabled())
                __slb_restore_bolted_realmode();

out:
        mtmsr(MSR_KERNEL);

        return srr1;
}

#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
/*
 * This is used in working around bugs in thread reconfiguration
 * on POWER9 (at least up to Nimbus DD2.2) relating to transactional
 * memory and the way that XER[SO] is checkpointed.
 * This function forces the core into SMT4 in order by asking
 * all other threads not to stop, and sending a message to any
 * that are in a stop state.
 * Must be called with preemption disabled.
 */
void pnv_power9_force_smt4_catch(void)
{
        int cpu, cpu0, thr;
        int awake_threads = 1;          /* this thread is awake */
        int poke_threads = 0;
        int need_awake = threads_per_core;

        cpu = smp_processor_id();
        cpu0 = cpu & ~(threads_per_core - 1);
        for (thr = 0; thr < threads_per_core; ++thr) {
                if (cpu != cpu0 + thr)
                        atomic_inc(&paca_ptrs[cpu0+thr]->dont_stop);
        }
        /* order setting dont_stop vs testing requested_psscr */
        smp_mb();
        for (thr = 0; thr < threads_per_core; ++thr) {
                if (!paca_ptrs[cpu0+thr]->requested_psscr)
                        ++awake_threads;
                else
                        poke_threads |= (1 << thr);
        }

        /* If at least 3 threads are awake, the core is in SMT4 already */
        if (awake_threads < need_awake) {
                /* We have to wake some threads; we'll use msgsnd */
                for (thr = 0; thr < threads_per_core; ++thr) {
                        if (poke_threads & (1 << thr)) {
                                ppc_msgsnd_sync();
                                ppc_msgsnd(PPC_DBELL_MSGTYPE, 0,
                                           paca_ptrs[cpu0+thr]->hw_cpu_id);
                        }
                }
                /* now spin until at least 3 threads are awake */
                do {
                        for (thr = 0; thr < threads_per_core; ++thr) {
                                if ((poke_threads & (1 << thr)) &&
                                    !paca_ptrs[cpu0+thr]->requested_psscr) {
                                        ++awake_threads;
                                        poke_threads &= ~(1 << thr);
                                }
                        }
                } while (awake_threads < need_awake);
        }
}
EXPORT_SYMBOL_GPL(pnv_power9_force_smt4_catch);

void pnv_power9_force_smt4_release(void)
{
        int cpu, cpu0, thr;

        cpu = smp_processor_id();
        cpu0 = cpu & ~(threads_per_core - 1);

        /* clear all the dont_stop flags */
        for (thr = 0; thr < threads_per_core; ++thr) {
                if (cpu != cpu0 + thr)
                        atomic_dec(&paca_ptrs[cpu0+thr]->dont_stop);
        }
}
EXPORT_SYMBOL_GPL(pnv_power9_force_smt4_release);
#endif /* CONFIG_KVM_BOOK3S_HV_POSSIBLE */

struct p10_sprs {
        /*
         * SPRs that get lost in shallow states:
         *
         * P10 loses CR, LR, CTR, FPSCR, VSCR, XER, TAR, SPRG2, and HSPRG1
         * isa300 idle routines restore CR, LR.
         * CTR is volatile
         * idle thread doesn't use FP or VEC
         * kernel doesn't use TAR
         * HSPRG1 is only live in HV interrupt entry
         * SPRG2 is only live in KVM guests, KVM handles it.
         */
};

static unsigned long power10_idle_stop(unsigned long psscr)
{
        int cpu = raw_smp_processor_id();
        int first = cpu_first_thread_sibling(cpu);
        unsigned long *state = &paca_ptrs[first]->idle_state;
        unsigned long core_thread_mask = (1UL << threads_per_core) - 1;
        unsigned long srr1;
        unsigned long pls;
//      struct p10_sprs sprs = {}; /* avoid false used-uninitialised */
        bool sprs_saved = false;

        if (!(psscr & (PSSCR_EC|PSSCR_ESL))) {
                /* EC=ESL=0 case */

                /*
                 * Wake synchronously. SRESET via xscom may still cause
                 * a 0x100 powersave wakeup with SRR1 reason!
                 */
                srr1 = isa300_idle_stop_noloss(psscr);          /* go idle */
                if (likely(!srr1))
                        return 0;

                /*
                 * Registers not saved, can't recover!
                 * This would be a hardware bug
                 */
                BUG_ON((srr1 & SRR1_WAKESTATE) != SRR1_WS_NOLOSS);

                goto out;
        }

        /* EC=ESL=1 case */
        if ((psscr & PSSCR_RL_MASK) >= deep_spr_loss_state) {
                /* XXX: save SPRs for deep state loss here. */

                sprs_saved = true;

                atomic_start_thread_idle();
        }

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

        psscr = mfspr(SPRN_PSSCR);

        WARN_ON_ONCE(!srr1);
        WARN_ON_ONCE(mfmsr() & (MSR_IR|MSR_DR));

        if (unlikely((srr1 & SRR1_WAKEMASK_P8) == SRR1_WAKEHMI))
                hmi_exception_realmode(NULL);

        /*
         * On POWER10, SRR1 bits do not match exactly as expected.
         * SRR1_WS_GPRLOSS (10b) can also result in SPR loss, so
         * just always test PSSCR for SPR/TB state loss.
         */
        pls = (psscr & PSSCR_PLS) >> PSSCR_PLS_SHIFT;
        if (likely(pls < deep_spr_loss_state)) {
                if (sprs_saved)
                        atomic_stop_thread_idle();
                goto out;
        }

        /* HV state loss */
        BUG_ON(!sprs_saved);

        atomic_lock_thread_idle();

        if ((*state & core_thread_mask) != 0)
                goto core_woken;

        /* XXX: restore per-core SPRs here */

        if (pls >= pnv_first_tb_loss_level) {
                /* TB loss */
                if (opal_resync_timebase() != OPAL_SUCCESS)
                        BUG();
        }

        /*
         * isync after restoring shared SPRs and before unlocking. Unlock
         * only contains hwsync which does not necessarily do the right
         * thing for SPRs.
         */
        isync();

core_woken:
        atomic_unlock_and_stop_thread_idle();

        /* XXX: restore per-thread SPRs here */

        if (!radix_enabled())
                __slb_restore_bolted_realmode();

out:
        mtmsr(MSR_KERNEL);

        return srr1;
}

#ifdef CONFIG_HOTPLUG_CPU
static unsigned long arch300_offline_stop(unsigned long psscr)
{
        unsigned long srr1;

        if (cpu_has_feature(CPU_FTR_ARCH_31))
                srr1 = power10_idle_stop(psscr);
        else
                srr1 = power9_idle_stop(psscr);

        return srr1;
}
#endif

void arch300_idle_type(unsigned long stop_psscr_val,
                                      unsigned long stop_psscr_mask)
{
        unsigned long psscr;
        unsigned long srr1;

        if (!prep_irq_for_idle_irqsoff())
                return;

        psscr = mfspr(SPRN_PSSCR);
        psscr = (psscr & ~stop_psscr_mask) | stop_psscr_val;

        __ppc64_runlatch_off();
        if (cpu_has_feature(CPU_FTR_ARCH_31))
                srr1 = power10_idle_stop(psscr);
        else
                srr1 = power9_idle_stop(psscr);
        __ppc64_runlatch_on();

        fini_irq_for_idle_irqsoff();

        irq_set_pending_from_srr1(srr1);
}

/*
 * Used for ppc_md.power_save which needs a function with no parameters
 */
static void arch300_idle(void)
{
        arch300_idle_type(pnv_default_stop_val, pnv_default_stop_mask);
}

#ifdef CONFIG_HOTPLUG_CPU

void pnv_program_cpu_hotplug_lpcr(unsigned int cpu, u64 lpcr_val)
{
        u64 pir = get_hard_smp_processor_id(cpu);

        mtspr(SPRN_LPCR, lpcr_val);

        /*
         * Program the LPCR via stop-api only if the deepest stop state
         * can lose hypervisor context.
         */
        if (supported_cpuidle_states & OPAL_PM_LOSE_FULL_CONTEXT)
                opal_slw_set_reg(pir, SPRN_LPCR, lpcr_val);
}

/*
 * pnv_cpu_offline: A function that puts the CPU into the deepest
 * available platform idle state on a CPU-Offline.
 * interrupts hard disabled and no lazy irq pending.
 */
unsigned long pnv_cpu_offline(unsigned int cpu)
{
        unsigned long srr1;

        __ppc64_runlatch_off();

        if (cpu_has_feature(CPU_FTR_ARCH_300) && deepest_stop_found) {
                unsigned long psscr;

                psscr = mfspr(SPRN_PSSCR);
                psscr = (psscr & ~pnv_deepest_stop_psscr_mask) |
                                                pnv_deepest_stop_psscr_val;
                srr1 = arch300_offline_stop(psscr);
        } else if (cpu_has_feature(CPU_FTR_ARCH_206) && power7_offline_type) {
                srr1 = power7_offline();
        } else {
                /* This is the fallback method. We emulate snooze */
                while (!generic_check_cpu_restart(cpu)) {
                        HMT_low();
                        HMT_very_low();
                }
                srr1 = 0;
                HMT_medium();
        }

        __ppc64_runlatch_on();

        return srr1;
}
#endif

/*
 * Power ISA 3.0 idle initialization.
 *
 * POWER ISA 3.0 defines a new SPR Processor stop Status and Control
 * Register (PSSCR) to control idle behavior.
 *
 * PSSCR layout:
 * ----------------------------------------------------------
 * | PLS | /// | SD | ESL | EC | PSLL | /// | TR | MTL | RL |
 * ----------------------------------------------------------
 * 0      4     41   42    43   44     48    54   56    60
 *
 * PSSCR key fields:
 *      Bits 0:3  - Power-Saving Level Status (PLS). This field indicates the
 *      lowest power-saving state the thread entered since stop instruction was
 *      last executed.
 *
 *      Bit 41 - Status Disable(SD)
 *      0 - Shows PLS entries
 *      1 - PLS entries are all 0
 *
 *      Bit 42 - Enable State Loss
 *      0 - No state is lost irrespective of other fields
 *      1 - Allows state loss
 *
 *      Bit 43 - Exit Criterion
 *      0 - Exit from power-save mode on any interrupt
 *      1 - Exit from power-save mode controlled by LPCR's PECE bits
 *
 *      Bits 44:47 - Power-Saving Level Limit
 *      This limits the power-saving level that can be entered into.
 *
 *      Bits 60:63 - Requested Level
 *      Used to specify which power-saving level must be entered on executing
 *      stop instruction
 */

int __init validate_psscr_val_mask(u64 *psscr_val, u64 *psscr_mask, u32 flags)
{
        int err = 0;

        /*
         * psscr_mask == 0xf indicates an older firmware.
         * Set remaining fields of psscr to the default values.
         * See NOTE above definition of PSSCR_HV_DEFAULT_VAL
         */
        if (*psscr_mask == 0xf) {
                *psscr_val = *psscr_val | PSSCR_HV_DEFAULT_VAL;
                *psscr_mask = PSSCR_HV_DEFAULT_MASK;
                return err;
        }

        /*
         * New firmware is expected to set the psscr_val bits correctly.
         * Validate that the following invariants are correctly maintained by
         * the new firmware.
         * - ESL bit value matches the EC bit value.
         * - ESL bit is set for all the deep stop states.
         */
        if (GET_PSSCR_ESL(*psscr_val) != GET_PSSCR_EC(*psscr_val)) {
                err = ERR_EC_ESL_MISMATCH;
        } else if ((flags & OPAL_PM_LOSE_FULL_CONTEXT) &&
                GET_PSSCR_ESL(*psscr_val) == 0) {
                err = ERR_DEEP_STATE_ESL_MISMATCH;
        }

        return err;
}

/*
 * pnv_arch300_idle_init: Initializes the default idle state, first
 *                        deep idle state and deepest idle state on
 *                        ISA 3.0 CPUs.
 *
 * @np: /ibm,opal/power-mgt device node
 * @flags: cpu-idle-state-flags array
 * @dt_idle_states: Number of idle state entries
 * Returns 0 on success
 */
static void __init pnv_arch300_idle_init(void)
{
        u64 max_residency_ns = 0;
        int i;

        /* stop is not really architected, we only have p9,p10 and p11 drivers */
        if (!pvr_version_is(PVR_POWER9) && !pvr_version_is(PVR_POWER10) &&
                !pvr_version_is(PVR_POWER11))
                return;

        /*
         * pnv_deepest_stop_{val,mask} should be set to values corresponding to
         * the deepest stop state.
         *
         * pnv_default_stop_{val,mask} should be set to values corresponding to
         * the deepest loss-less (OPAL_PM_STOP_INST_FAST) stop state.
         */
        pnv_first_tb_loss_level = MAX_STOP_STATE + 1;
        deep_spr_loss_state = MAX_STOP_STATE + 1;
        for (i = 0; i < nr_pnv_idle_states; i++) {
                int err;
                struct pnv_idle_states_t *state = &pnv_idle_states[i];
                u64 psscr_rl = state->psscr_val & PSSCR_RL_MASK;

                /* No deep loss driver implemented for POWER10 and POWER11 yet */
                if ((pvr_version_is(PVR_POWER10) || pvr_version_is(PVR_POWER11)) &&
                                state->flags & (OPAL_PM_TIMEBASE_STOP|OPAL_PM_LOSE_FULL_CONTEXT))
                        continue;

                if ((state->flags & OPAL_PM_TIMEBASE_STOP) &&
                     (pnv_first_tb_loss_level > psscr_rl))
                        pnv_first_tb_loss_level = psscr_rl;

                if ((state->flags & OPAL_PM_LOSE_FULL_CONTEXT) &&
                     (deep_spr_loss_state > psscr_rl))
                        deep_spr_loss_state = psscr_rl;

                /*
                 * The idle code does not deal with TB loss occurring
                 * in a shallower state than SPR loss, so force it to
                 * behave like SPRs are lost if TB is lost. POWER9 would
                 * never encounter this, but a POWER8 core would if it
                 * implemented the stop instruction. So this is for forward
                 * compatibility.
                 */
                if ((state->flags & OPAL_PM_TIMEBASE_STOP) &&
                     (deep_spr_loss_state > psscr_rl))
                        deep_spr_loss_state = psscr_rl;

                err = validate_psscr_val_mask(&state->psscr_val,
                                              &state->psscr_mask,
                                              state->flags);
                if (err) {
                        report_invalid_psscr_val(state->psscr_val, err);
                        continue;
                }

                state->valid = true;

                if (max_residency_ns < state->residency_ns) {
                        max_residency_ns = state->residency_ns;
                        pnv_deepest_stop_psscr_val = state->psscr_val;
                        pnv_deepest_stop_psscr_mask = state->psscr_mask;
                        pnv_deepest_stop_flag = state->flags;
                        deepest_stop_found = true;
                }

                if (!default_stop_found &&
                    (state->flags & OPAL_PM_STOP_INST_FAST)) {
                        pnv_default_stop_val = state->psscr_val;
                        pnv_default_stop_mask = state->psscr_mask;
                        default_stop_found = true;
                        WARN_ON(state->flags & OPAL_PM_LOSE_FULL_CONTEXT);
                }
        }

        if (unlikely(!default_stop_found)) {
                pr_warn("cpuidle-powernv: No suitable default stop state found. Disabling platform idle.\n");
        } else {
                ppc_md.power_save = arch300_idle;
                pr_info("cpuidle-powernv: Default stop: psscr = 0x%016llx,mask=0x%016llx\n",
                        pnv_default_stop_val, pnv_default_stop_mask);
        }

        if (unlikely(!deepest_stop_found)) {
                pr_warn("cpuidle-powernv: No suitable stop state for CPU-Hotplug. Offlined CPUs will busy wait");
        } else {
                pr_info("cpuidle-powernv: Deepest stop: psscr = 0x%016llx,mask=0x%016llx\n",
                        pnv_deepest_stop_psscr_val,
                        pnv_deepest_stop_psscr_mask);
        }

        pr_info("cpuidle-powernv: First stop level that may lose SPRs = 0x%llx\n",
                deep_spr_loss_state);

        pr_info("cpuidle-powernv: First stop level that may lose timebase = 0x%llx\n",
                pnv_first_tb_loss_level);
}

static void __init pnv_disable_deep_states(void)
{
        /*
         * The stop-api is unable to restore hypervisor
         * resources on wakeup from platform idle states which
         * lose full context. So disable such states.
         */
        supported_cpuidle_states &= ~OPAL_PM_LOSE_FULL_CONTEXT;
        pr_warn("cpuidle-powernv: Disabling idle states that lose full context\n");
        pr_warn("cpuidle-powernv: Idle power-savings, CPU-Hotplug affected\n");

        if (cpu_has_feature(CPU_FTR_ARCH_300) &&
            (pnv_deepest_stop_flag & OPAL_PM_LOSE_FULL_CONTEXT)) {
                /*
                 * Use the default stop state for CPU-Hotplug
                 * if available.
                 */
                if (default_stop_found) {
                        pnv_deepest_stop_psscr_val = pnv_default_stop_val;
                        pnv_deepest_stop_psscr_mask = pnv_default_stop_mask;
                        pr_warn("cpuidle-powernv: Offlined CPUs will stop with psscr = 0x%016llx\n",
                                pnv_deepest_stop_psscr_val);
                } else { /* Fallback to snooze loop for CPU-Hotplug */
                        deepest_stop_found = false;
                        pr_warn("cpuidle-powernv: Offlined CPUs will busy wait\n");
                }
        }
}

/*
 * Probe device tree for supported idle states
 */
static void __init pnv_probe_idle_states(void)
{
        int i;

        if (nr_pnv_idle_states < 0) {
                pr_warn("cpuidle-powernv: no idle states found in the DT\n");
                return;
        }

        if (cpu_has_feature(CPU_FTR_ARCH_300))
                pnv_arch300_idle_init();

        for (i = 0; i < nr_pnv_idle_states; i++)
                supported_cpuidle_states |= pnv_idle_states[i].flags;
}

/*
 * This function parses device-tree and populates all the information
 * into pnv_idle_states structure. It also sets up nr_pnv_idle_states
 * which is the number of cpuidle states discovered through device-tree.
 */

static int __init pnv_parse_cpuidle_dt(void)
{
        struct device_node *np;
        int nr_idle_states, i;
        int rc = 0;
        u32 *temp_u32;
        u64 *temp_u64;
        const char **temp_string;

        np = of_find_node_by_path("/ibm,opal/power-mgt");
        if (!np) {
                pr_warn("opal: PowerMgmt Node not found\n");
                return -ENODEV;
        }
        nr_idle_states = of_property_count_u32_elems(np,
                                                "ibm,cpu-idle-state-flags");

        pnv_idle_states = kzalloc_objs(*pnv_idle_states, nr_idle_states);
        temp_u32 = kcalloc(nr_idle_states, sizeof(u32),  GFP_KERNEL);
        temp_u64 = kcalloc(nr_idle_states, sizeof(u64),  GFP_KERNEL);
        temp_string = kcalloc(nr_idle_states, sizeof(char *),  GFP_KERNEL);

        if (!(pnv_idle_states && temp_u32 && temp_u64 && temp_string)) {
                pr_err("Could not allocate memory for dt parsing\n");
                rc = -ENOMEM;
                goto out;
        }

        /* Read flags */
        if (of_property_read_u32_array(np, "ibm,cpu-idle-state-flags",
                                       temp_u32, nr_idle_states)) {
                pr_warn("cpuidle-powernv: missing ibm,cpu-idle-state-flags in DT\n");
                rc = -EINVAL;
                goto out;
        }
        for (i = 0; i < nr_idle_states; i++)
                pnv_idle_states[i].flags = temp_u32[i];

        /* Read latencies */
        if (of_property_read_u32_array(np, "ibm,cpu-idle-state-latencies-ns",
                                       temp_u32, nr_idle_states)) {
                pr_warn("cpuidle-powernv: missing ibm,cpu-idle-state-latencies-ns in DT\n");
                rc = -EINVAL;
                goto out;
        }
        for (i = 0; i < nr_idle_states; i++)
                pnv_idle_states[i].latency_ns = temp_u32[i];

        /* Read residencies */
        if (of_property_read_u32_array(np, "ibm,cpu-idle-state-residency-ns",
                                       temp_u32, nr_idle_states)) {
                pr_warn("cpuidle-powernv: missing ibm,cpu-idle-state-residency-ns in DT\n");
                rc = -EINVAL;
                goto out;
        }
        for (i = 0; i < nr_idle_states; i++)
                pnv_idle_states[i].residency_ns = temp_u32[i];

        /* For power9 and later */
        if (cpu_has_feature(CPU_FTR_ARCH_300)) {
                /* Read pm_crtl_val */
                if (of_property_read_u64_array(np, "ibm,cpu-idle-state-psscr",
                                               temp_u64, nr_idle_states)) {
                        pr_warn("cpuidle-powernv: missing ibm,cpu-idle-state-psscr in DT\n");
                        rc = -EINVAL;
                        goto out;
                }
                for (i = 0; i < nr_idle_states; i++)
                        pnv_idle_states[i].psscr_val = temp_u64[i];

                /* Read pm_crtl_mask */
                if (of_property_read_u64_array(np, "ibm,cpu-idle-state-psscr-mask",
                                               temp_u64, nr_idle_states)) {
                        pr_warn("cpuidle-powernv: missing ibm,cpu-idle-state-psscr-mask in DT\n");
                        rc = -EINVAL;
                        goto out;
                }
                for (i = 0; i < nr_idle_states; i++)
                        pnv_idle_states[i].psscr_mask = temp_u64[i];
        }

        /*
         * power8 specific properties ibm,cpu-idle-state-pmicr-mask and
         * ibm,cpu-idle-state-pmicr-val were never used and there is no
         * plan to use it in near future. Hence, not parsing these properties
         */

        if (of_property_read_string_array(np, "ibm,cpu-idle-state-names",
                                          temp_string, nr_idle_states) < 0) {
                pr_warn("cpuidle-powernv: missing ibm,cpu-idle-state-names in DT\n");
                rc = -EINVAL;
                goto out;
        }
        for (i = 0; i < nr_idle_states; i++)
                strscpy(pnv_idle_states[i].name, temp_string[i],
                        PNV_IDLE_NAME_LEN);
        nr_pnv_idle_states = nr_idle_states;
        rc = 0;
out:
        kfree(temp_u32);
        kfree(temp_u64);
        kfree(temp_string);
        of_node_put(np);
        return rc;
}

static int __init pnv_init_idle_states(void)
{
        int cpu;
        int rc = 0;

        /* Set up PACA fields */
        for_each_present_cpu(cpu) {
                struct paca_struct *p = paca_ptrs[cpu];

                p->idle_state = 0;
                if (cpu == cpu_first_thread_sibling(cpu))
                        p->idle_state = (1 << threads_per_core) - 1;

                if (!cpu_has_feature(CPU_FTR_ARCH_300)) {
                        /* P7/P8 nap */
                        p->thread_idle_state = PNV_THREAD_RUNNING;
                } else if (pvr_version_is(PVR_POWER9)) {
                        /* P9 stop workarounds */
#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
                        p->requested_psscr = 0;
                        atomic_set(&p->dont_stop, 0);
#endif
                }
        }

        /* In case we error out nr_pnv_idle_states will be zero */
        nr_pnv_idle_states = 0;
        supported_cpuidle_states = 0;

        if (cpuidle_disable != IDLE_NO_OVERRIDE)
                goto out;
        rc = pnv_parse_cpuidle_dt();
        if (rc)
                return rc;
        pnv_probe_idle_states();

        if (!cpu_has_feature(CPU_FTR_ARCH_300)) {
                if (!(supported_cpuidle_states & OPAL_PM_SLEEP_ENABLED_ER1)) {
                        power7_fastsleep_workaround_entry = false;
                        power7_fastsleep_workaround_exit = false;
                } else {
                        struct device *dev_root;
                        /*
                         * OPAL_PM_SLEEP_ENABLED_ER1 is set. It indicates that
                         * workaround is needed to use fastsleep. Provide sysfs
                         * control to choose how this workaround has to be
                         * applied.
                         */
                        dev_root = bus_get_dev_root(&cpu_subsys);
                        if (dev_root) {
                                device_create_file(dev_root,
                                                   &dev_attr_fastsleep_workaround_applyonce);
                                put_device(dev_root);
                        }
                }

                update_subcore_sibling_mask();

                if (supported_cpuidle_states & OPAL_PM_NAP_ENABLED) {
                        ppc_md.power_save = power7_idle;
                        power7_offline_type = PNV_THREAD_NAP;
                }

                if ((supported_cpuidle_states & OPAL_PM_WINKLE_ENABLED) &&
                           (supported_cpuidle_states & OPAL_PM_LOSE_FULL_CONTEXT))
                        power7_offline_type = PNV_THREAD_WINKLE;
                else if ((supported_cpuidle_states & OPAL_PM_SLEEP_ENABLED) ||
                           (supported_cpuidle_states & OPAL_PM_SLEEP_ENABLED_ER1))
                        power7_offline_type = PNV_THREAD_SLEEP;
        }

        if (supported_cpuidle_states & OPAL_PM_LOSE_FULL_CONTEXT) {
                if (pnv_save_sprs_for_deep_states())
                        pnv_disable_deep_states();
        }

out:
        return 0;
}
machine_subsys_initcall(powernv, pnv_init_idle_states);