diff options
Diffstat (limited to 'arch/powerpc/platforms/powernv/smp.c')
| -rw-r--r-- | arch/powerpc/platforms/powernv/smp.c | 221 |
1 files changed, 221 insertions, 0 deletions
diff --git a/arch/powerpc/platforms/powernv/smp.c b/arch/powerpc/platforms/powernv/smp.c new file mode 100644 index 00000000000..5fcfcf44e3a --- /dev/null +++ b/arch/powerpc/platforms/powernv/smp.c @@ -0,0 +1,221 @@ +/* + * SMP support for PowerNV machines. + * + * Copyright 2011 IBM Corp. + * + * 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/kernel.h> +#include <linux/module.h> +#include <linux/sched.h> +#include <linux/smp.h> +#include <linux/interrupt.h> +#include <linux/delay.h> +#include <linux/init.h> +#include <linux/spinlock.h> +#include <linux/cpu.h> + +#include <asm/irq.h> +#include <asm/smp.h> +#include <asm/paca.h> +#include <asm/machdep.h> +#include <asm/cputable.h> +#include <asm/firmware.h> +#include <asm/rtas.h> +#include <asm/vdso_datapage.h> +#include <asm/cputhreads.h> +#include <asm/xics.h> +#include <asm/opal.h> +#include <asm/runlatch.h> +#include <asm/code-patching.h> +#include <asm/dbell.h> + +#include "powernv.h" + +#ifdef DEBUG +#include <asm/udbg.h> +#define DBG(fmt...) udbg_printf(fmt) +#else +#define DBG(fmt...) +#endif + +static void pnv_smp_setup_cpu(int cpu) +{ + if (cpu != boot_cpuid) + xics_setup_cpu(); + +#ifdef CONFIG_PPC_DOORBELL + if (cpu_has_feature(CPU_FTR_DBELL)) + doorbell_setup_this_cpu(); +#endif +} + +int pnv_smp_kick_cpu(int nr) +{ + unsigned int pcpu = get_hard_smp_processor_id(nr); + unsigned long start_here = + __pa(ppc_function_entry(generic_secondary_smp_init)); + long rc; + + BUG_ON(nr < 0 || nr >= NR_CPUS); + + /* + * If we already started or OPALv2 is not supported, we just + * kick the CPU via the PACA + */ + if (paca[nr].cpu_start || !firmware_has_feature(FW_FEATURE_OPALv2)) + goto kick; + + /* + * At this point, the CPU can either be spinning on the way in + * from kexec or be inside OPAL waiting to be started for the + * first time. OPAL v3 allows us to query OPAL to know if it + * has the CPUs, so we do that + */ + if (firmware_has_feature(FW_FEATURE_OPALv3)) { + uint8_t status; + + rc = opal_query_cpu_status(pcpu, &status); + if (rc != OPAL_SUCCESS) { + pr_warn("OPAL Error %ld querying CPU %d state\n", + rc, nr); + return -ENODEV; + } + + /* + * Already started, just kick it, probably coming from + * kexec and spinning + */ + if (status == OPAL_THREAD_STARTED) + goto kick; + + /* + * Available/inactive, let's kick it + */ + if (status == OPAL_THREAD_INACTIVE) { + pr_devel("OPAL: Starting CPU %d (HW 0x%x)...\n", + nr, pcpu); + rc = opal_start_cpu(pcpu, start_here); + if (rc != OPAL_SUCCESS) { + pr_warn("OPAL Error %ld starting CPU %d\n", + rc, nr); + return -ENODEV; + } + } else { + /* + * An unavailable CPU (or any other unknown status) + * shouldn't be started. It should also + * not be in the possible map but currently it can + * happen + */ + pr_devel("OPAL: CPU %d (HW 0x%x) is unavailable" + " (status %d)...\n", nr, pcpu, status); + return -ENODEV; + } + } else { + /* + * On OPAL v2, we just kick it and hope for the best, + * we must not test the error from opal_start_cpu() or + * we would fail to get CPUs from kexec. + */ + opal_start_cpu(pcpu, start_here); + } + kick: + return smp_generic_kick_cpu(nr); +} + +#ifdef CONFIG_HOTPLUG_CPU + +static int pnv_smp_cpu_disable(void) +{ + int cpu = smp_processor_id(); + + /* This is identical to pSeries... might consolidate by + * moving migrate_irqs_away to a ppc_md with default to + * the generic fixup_irqs. --BenH. + */ + set_cpu_online(cpu, false); + vdso_data->processorCount--; + if (cpu == boot_cpuid) + boot_cpuid = cpumask_any(cpu_online_mask); + xics_migrate_irqs_away(); + return 0; +} + +static void pnv_smp_cpu_kill_self(void) +{ + unsigned int cpu; + + /* Standard hot unplug procedure */ + local_irq_disable(); + idle_task_exit(); + current->active_mm = NULL; /* for sanity */ + cpu = smp_processor_id(); + DBG("CPU%d offline\n", cpu); + generic_set_cpu_dead(cpu); + smp_wmb(); + + /* We don't want to take decrementer interrupts while we are offline, + * so clear LPCR:PECE1. We keep PECE2 enabled. + */ + mtspr(SPRN_LPCR, mfspr(SPRN_LPCR) & ~(u64)LPCR_PECE1); + while (!generic_check_cpu_restart(cpu)) { + ppc64_runlatch_off(); + power7_nap(1); + ppc64_runlatch_on(); + + /* Reenable IRQs briefly to clear the IPI that woke us */ + local_irq_enable(); + local_irq_disable(); + mb(); + + if (cpu_core_split_required()) + continue; + + if (!generic_check_cpu_restart(cpu)) + DBG("CPU%d Unexpected exit while offline !\n", cpu); + } + mtspr(SPRN_LPCR, mfspr(SPRN_LPCR) | LPCR_PECE1); + DBG("CPU%d coming online...\n", cpu); +} + +#endif /* CONFIG_HOTPLUG_CPU */ + +static struct smp_ops_t pnv_smp_ops = { + .message_pass = smp_muxed_ipi_message_pass, + .cause_ipi = NULL, /* Filled at runtime by xics_smp_probe() */ + .probe = xics_smp_probe, + .kick_cpu = pnv_smp_kick_cpu, + .setup_cpu = pnv_smp_setup_cpu, + .cpu_bootable = smp_generic_cpu_bootable, +#ifdef CONFIG_HOTPLUG_CPU + .cpu_disable = pnv_smp_cpu_disable, + .cpu_die = generic_cpu_die, +#endif /* CONFIG_HOTPLUG_CPU */ +}; + +/* This is called very early during platform setup_arch */ +void __init pnv_smp_init(void) +{ + smp_ops = &pnv_smp_ops; + + /* XXX We don't yet have a proper entry point from HAL, for + * now we rely on kexec-style entry from BML + */ + +#ifdef CONFIG_PPC_RTAS + /* Non-lpar has additional take/give timebase */ + if (rtas_token("freeze-time-base") != RTAS_UNKNOWN_SERVICE) { + smp_ops->give_timebase = rtas_give_timebase; + smp_ops->take_timebase = rtas_take_timebase; + } +#endif /* CONFIG_PPC_RTAS */ + +#ifdef CONFIG_HOTPLUG_CPU + ppc_md.cpu_die = pnv_smp_cpu_kill_self; +#endif +} |