Re: [RFC PATCH v2 2/3] powernv/cpuidle: Pass pointers instead of values to stop loop

From: Frank Rowand
Date: Thu Oct 11 2018 - 15:56:08 EST

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In reply to: Akshay Adiga: "[RFC PATCH v2 2/3] powernv/cpuidle: Pass pointers instead of values to stop loop"
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+ devicetree mail list

On 10/11/18 06:22, Akshay Adiga wrote:
> Passing pointer to the pnv_idle_state instead of psscr value and mask.
> This helps us to pass more information to the stop loop. This will help to
> figure out the method to enter/exit idle state.
>
> Signed-off-by: Akshay Adiga <akshay.adiga@xxxxxxxxxxxxxxxxxx>
>
> ---
> Changes from v1 :
> - Code is rebased on Nick Piggin's v4 patch "powerpc/64s: reimplement book3s
> idle code in C"
>
> arch/powerpc/include/asm/processor.h | 5 ++-
> arch/powerpc/platforms/powernv/idle.c | 47 ++++++++++-----------------
> drivers/cpuidle/cpuidle-powernv.c | 15 +++------
> 3 files changed, 24 insertions(+), 43 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/processor.h b/arch/powerpc/include/asm/processor.h
> index 936795acba48..822d3236ad7f 100644
> --- a/arch/powerpc/include/asm/processor.h
> +++ b/arch/powerpc/include/asm/processor.h
> @@ -43,6 +43,7 @@
> #include <asm/thread_info.h>
> #include <asm/ptrace.h>
> #include <asm/hw_breakpoint.h>
> +#include <asm/cpuidle.h>
>
> /* We do _not_ want to define new machine types at all, those must die
> * in favor of using the device-tree
> @@ -518,9 +519,7 @@ 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_idle_type(unsigned long type);
> -extern void power9_idle_type(unsigned long stop_psscr_val,
> - unsigned long stop_psscr_mask);
> -
> +extern void power9_idle_type(struct pnv_idle_states_t *state);
> extern void flush_instruction_cache(void);
> extern void hard_reset_now(void);
> extern void poweroff_now(void);
> diff --git a/arch/powerpc/platforms/powernv/idle.c b/arch/powerpc/platforms/powernv/idle.c
> index 755918402591..681a23a066bb 100644
> --- a/arch/powerpc/platforms/powernv/idle.c
> +++ b/arch/powerpc/platforms/powernv/idle.c
> @@ -44,8 +44,7 @@ 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;
> +struct pnv_idle_states_t *pnv_default_state;
> static bool default_stop_found;
>
> /*
> @@ -72,9 +71,7 @@ const int nr_known_versions = 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 struct pnv_idle_states_t *pnv_deepest_state;
> static bool deepest_stop_found;
>
> static unsigned long power7_offline_type;
> @@ -96,7 +93,7 @@ static int pnv_save_sprs_for_deep_states(void)
> uint64_t hid5_val = mfspr(SPRN_HID5);
> uint64_t hmeer_val = mfspr(SPRN_HMEER);
> uint64_t msr_val = MSR_IDLE;
> - uint64_t psscr_val = pnv_deepest_stop_psscr_val;
> + uint64_t psscr_val = pnv_deepest_state->psscr_val;
>
> for_each_present_cpu(cpu) {
> uint64_t pir = get_hard_smp_processor_id(cpu);
> @@ -820,17 +817,15 @@ static unsigned long power9_offline_stop(unsigned long psscr)
> return srr1;
> }
>
> -static unsigned long __power9_idle_type(unsigned long stop_psscr_val,
> - unsigned long stop_psscr_mask)
> +static unsigned long __power9_idle_type(struct pnv_idle_states_t *state)
> {
> unsigned long psscr;
> unsigned long srr1;
>
> if (!prep_irq_for_idle_irqsoff())
> return 0;
> -
> psscr = mfspr(SPRN_PSSCR);
> - psscr = (psscr & ~stop_psscr_mask) | stop_psscr_val;
> + psscr = (psscr & ~state->psscr_mask) | state->psscr_val;
>
> __ppc64_runlatch_off();
> srr1 = power9_idle_stop(psscr, true);
> @@ -841,12 +836,10 @@ static unsigned long __power9_idle_type(unsigned long stop_psscr_val,
> return srr1;
> }
>
> -void power9_idle_type(unsigned long stop_psscr_val,
> - unsigned long stop_psscr_mask)
> +void power9_idle_type(struct pnv_idle_states_t *state)
> {
> unsigned long srr1;
> -
> - srr1 = __power9_idle_type(stop_psscr_val, stop_psscr_mask);
> + srr1 = __power9_idle_type(state);
> irq_set_pending_from_srr1(srr1);
> }
>
> @@ -855,7 +848,7 @@ void power9_idle_type(unsigned long stop_psscr_val,
> */
> void power9_idle(void)
> {
> - power9_idle_type(pnv_default_stop_val, pnv_default_stop_mask);
> + power9_idle_type(pnv_default_state);
> }
>
> #ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
> @@ -974,8 +967,8 @@ unsigned long pnv_cpu_offline(unsigned int cpu)
> unsigned long psscr;
>
> psscr = mfspr(SPRN_PSSCR);
> - psscr = (psscr & ~pnv_deepest_stop_psscr_mask) |
> - pnv_deepest_stop_psscr_val;
> + psscr = (psscr & ~pnv_deepest_state->psscr_mask) |
> + pnv_deepest_state->psscr_val;
> srr1 = power9_offline_stop(psscr);
> } else if (cpu_has_feature(CPU_FTR_ARCH_206) && power7_offline_type) {
> srr1 = power7_offline();
> @@ -1123,16 +1116,13 @@ static void __init pnv_power9_idle_init(void)
>
> 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;
> + pnv_deepest_state = state;
> 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;
> + pnv_default_state = state;
> default_stop_found = true;
> WARN_ON(state->flags & OPAL_PM_LOSE_FULL_CONTEXT);
> }
> @@ -1143,15 +1133,15 @@ static void __init pnv_power9_idle_init(void)
> } else {
> ppc_md.power_save = power9_idle;
> pr_info("cpuidle-powernv: Default stop: psscr = 0x%016llx,mask=0x%016llx\n",
> - pnv_default_stop_val, pnv_default_stop_mask);
> + pnv_default_state->psscr_val, pnv_default_state->psscr_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);
> + pnv_deepest_state->psscr_val,
> + pnv_deepest_state->psscr_mask);
> }
>
> pr_info("cpuidle-powernv: First stop level that may lose SPRs = 0x%lld\n",
> @@ -1173,16 +1163,15 @@ static void __init pnv_disable_deep_states(void)
> 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)) {
> + (pnv_deepest_state->flags & 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;
> + pnv_deepest_state = pnv_default_state;
> pr_warn("cpuidle-powernv: Offlined CPUs will stop with psscr = 0x%016llx\n",
> - pnv_deepest_stop_psscr_val);
> + pnv_deepest_state->psscr_val);
> } else { /* Fallback to snooze loop for CPU-Hotplug */
> deepest_stop_found = false;
> pr_warn("cpuidle-powernv: Offlined CPUs will busy wait\n");
> diff --git a/drivers/cpuidle/cpuidle-powernv.c b/drivers/cpuidle/cpuidle-powernv.c
> index a15514ebd1c3..5116d5991d30 100644
> --- a/drivers/cpuidle/cpuidle-powernv.c
> +++ b/drivers/cpuidle/cpuidle-powernv.c
> @@ -35,13 +35,7 @@ static struct cpuidle_driver powernv_idle_driver = {
> static int max_idle_state __read_mostly;
> static struct cpuidle_state *cpuidle_state_table __read_mostly;
>
> -struct stop_psscr_table {
> - u64 val;
> - u64 mask;
> -};
> -
> -static struct stop_psscr_table stop_psscr_table[CPUIDLE_STATE_MAX] __read_mostly;
> -
> +struct pnv_idle_states_t idx_to_state_ptr[CPUIDLE_STATE_MAX] __read_mostly;
> static u64 default_snooze_timeout __read_mostly;
> static bool snooze_timeout_en __read_mostly;
>
> @@ -143,8 +137,9 @@ static int stop_loop(struct cpuidle_device *dev,
> struct cpuidle_driver *drv,
> int index)
> {
> - power9_idle_type(stop_psscr_table[index].val,
> - stop_psscr_table[index].mask);
> + struct pnv_idle_states_t *state;
> + state = &pnv_idle_states[index];
> + power9_idle_type(state);
> return index;
> }
>
> @@ -242,8 +237,6 @@ static inline void add_powernv_state(int index, const char *name,
> powernv_states[index].exit_latency = exit_latency;
> powernv_states[index].enter = idle_fn;
> /* For power8 and below psscr_* will be 0 */
> - stop_psscr_table[index].val = psscr_val;
> - stop_psscr_table[index].mask = psscr_mask;
> }
>
> /*
>

Next message: Frank Rowand: "Re: [RFC PATCH v2 3/3] cpuidle/powernv: save-restore sprs in opal"
Previous message: Frank Rowand: "Re: [RFC PATCH v2 1/3] cpuidle/powernv: Add support for states with ibm,cpuidle-state-v1"
In reply to: Akshay Adiga: "[RFC PATCH v2 2/3] powernv/cpuidle: Pass pointers instead of values to stop loop"
Next in thread: Akshay Adiga: "[RFC PATCH v2 3/3] cpuidle/powernv: save-restore sprs in opal"
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