diff options
Diffstat (limited to 'arch/powerpc/platforms/powernv/idle.c')
| -rw-r--r-- | arch/powerpc/platforms/powernv/idle.c | 75 |
1 files changed, 71 insertions, 4 deletions
diff --git a/arch/powerpc/platforms/powernv/idle.c b/arch/powerpc/platforms/powernv/idle.c index 2abee070373f..9f59041a172b 100644 --- a/arch/powerpc/platforms/powernv/idle.c +++ b/arch/powerpc/platforms/powernv/idle.c @@ -56,6 +56,7 @@ u64 pnv_first_deep_stop_state = MAX_STOP_STATE; */ 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 int pnv_save_sprs_for_deep_states(void) @@ -68,7 +69,7 @@ static int pnv_save_sprs_for_deep_states(void) * 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) & ~(u64)LPCR_PECE1; + uint64_t lpcr_val = mfspr(SPRN_LPCR); uint64_t hid0_val = mfspr(SPRN_HID0); uint64_t hid1_val = mfspr(SPRN_HID1); uint64_t hid4_val = mfspr(SPRN_HID4); @@ -185,8 +186,40 @@ static void pnv_alloc_idle_core_states(void) update_subcore_sibling_mask(); - if (supported_cpuidle_states & OPAL_PM_LOSE_FULL_CONTEXT) - pnv_save_sprs_for_deep_states(); + if (supported_cpuidle_states & OPAL_PM_LOSE_FULL_CONTEXT) { + int rc = pnv_save_sprs_for_deep_states(); + + if (likely(!rc)) + return; + + /* + * 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"); + } + } + } } u32 pnv_get_supported_cpuidle_states(void) @@ -355,6 +388,14 @@ void power9_idle(void) } #ifdef CONFIG_HOTPLUG_CPU +static 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); + 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. @@ -364,6 +405,20 @@ unsigned long pnv_cpu_offline(unsigned int cpu) { unsigned long srr1; u32 idle_states = pnv_get_supported_cpuidle_states(); + u64 lpcr_val; + + /* + * We don't want to take decrementer interrupts while we are + * offline, so clear LPCR:PECE1. We keep PECE2 (and + * LPCR_PECE_HVEE on P9) enabled as to let IPIs in. + * + * If the CPU gets woken up by a special wakeup, ensure that + * the SLW engine sets LPCR with decrementer bit cleared, else + * the CPU will come back to the kernel due to a spurious + * wakeup. + */ + lpcr_val = mfspr(SPRN_LPCR) & ~(u64)LPCR_PECE1; + pnv_program_cpu_hotplug_lpcr(cpu, lpcr_val); __ppc64_runlatch_off(); @@ -375,7 +430,8 @@ unsigned long pnv_cpu_offline(unsigned int cpu) pnv_deepest_stop_psscr_val; srr1 = power9_idle_stop(psscr); - } else if (idle_states & OPAL_PM_WINKLE_ENABLED) { + } else if ((idle_states & OPAL_PM_WINKLE_ENABLED) && + (idle_states & OPAL_PM_LOSE_FULL_CONTEXT)) { srr1 = power7_idle_insn(PNV_THREAD_WINKLE); } else if ((idle_states & OPAL_PM_SLEEP_ENABLED) || (idle_states & OPAL_PM_SLEEP_ENABLED_ER1)) { @@ -394,6 +450,16 @@ unsigned long pnv_cpu_offline(unsigned int cpu) __ppc64_runlatch_on(); + /* + * Re-enable decrementer interrupts in LPCR. + * + * Further, we want stop states to be woken up by decrementer + * for non-hotplug cases. So program the LPCR via stop api as + * well. + */ + lpcr_val = mfspr(SPRN_LPCR) | (u64)LPCR_PECE1; + pnv_program_cpu_hotplug_lpcr(cpu, lpcr_val); + return srr1; } #endif @@ -553,6 +619,7 @@ static int __init pnv_power9_idle_init(struct device_node *np, u32 *flags, max_residency_ns = residency_ns[i]; pnv_deepest_stop_psscr_val = psscr_val[i]; pnv_deepest_stop_psscr_mask = psscr_mask[i]; + pnv_deepest_stop_flag = flags[i]; deepest_stop_found = true; } |