diff options
Diffstat (limited to 'arch/powerpc/platforms/powernv/idle.c')
| -rw-r--r-- | arch/powerpc/platforms/powernv/idle.c | 34 |
1 files changed, 33 insertions, 1 deletions
diff --git a/arch/powerpc/platforms/powernv/idle.c b/arch/powerpc/platforms/powernv/idle.c index a553aeea7af6..9f59041a172b 100644 --- a/arch/powerpc/platforms/powernv/idle.c +++ b/arch/powerpc/platforms/powernv/idle.c @@ -69,7 +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); @@ -388,6 +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. @@ -397,6 +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(); @@ -428,6 +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 |