2 * SMP support for PowerNV machines.
4 * Copyright 2011 IBM Corp.
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
12 #include <linux/kernel.h>
13 #include <linux/module.h>
14 #include <linux/sched.h>
15 #include <linux/smp.h>
16 #include <linux/interrupt.h>
17 #include <linux/delay.h>
18 #include <linux/init.h>
19 #include <linux/spinlock.h>
20 #include <linux/cpu.h>
25 #include <asm/machdep.h>
26 #include <asm/cputable.h>
27 #include <asm/firmware.h>
29 #include <asm/vdso_datapage.h>
30 #include <asm/cputhreads.h>
38 #define DBG(fmt...) udbg_printf(fmt)
43 static void __cpuinit pnv_smp_setup_cpu(int cpu)
45 if (cpu != boot_cpuid)
49 static int pnv_smp_cpu_bootable(unsigned int nr)
51 /* Special case - we inhibit secondary thread startup
52 * during boot if the user requests it.
54 if (system_state < SYSTEM_RUNNING && cpu_has_feature(CPU_FTR_SMT)) {
55 if (!smt_enabled_at_boot && cpu_thread_in_core(nr) != 0)
57 if (smt_enabled_at_boot
58 && cpu_thread_in_core(nr) >= smt_enabled_at_boot)
65 int pnv_smp_kick_cpu(int nr)
67 unsigned int pcpu = get_hard_smp_processor_id(nr);
68 unsigned long start_here = __pa(*((unsigned long *)
69 generic_secondary_smp_init));
72 BUG_ON(nr < 0 || nr >= NR_CPUS);
74 /* On OPAL v2 the CPU are still spinning inside OPAL itself,
77 if (!paca[nr].cpu_start && firmware_has_feature(FW_FEATURE_OPALv2)) {
78 pr_devel("OPAL: Starting CPU %d (HW 0x%x)...\n", nr, pcpu);
79 rc = opal_start_cpu(pcpu, start_here);
80 if (rc != OPAL_SUCCESS) {
81 pr_warn("OPAL Error %ld starting CPU %d\n",
86 return smp_generic_kick_cpu(nr);
89 #ifdef CONFIG_HOTPLUG_CPU
91 static int pnv_smp_cpu_disable(void)
93 int cpu = smp_processor_id();
95 /* This is identical to pSeries... might consolidate by
96 * moving migrate_irqs_away to a ppc_md with default to
97 * the generic fixup_irqs. --BenH.
99 set_cpu_online(cpu, false);
100 vdso_data->processorCount--;
101 if (cpu == boot_cpuid)
102 boot_cpuid = cpumask_any(cpu_online_mask);
103 xics_migrate_irqs_away();
107 static void pnv_smp_cpu_kill_self(void)
111 /* Standard hot unplug procedure */
114 current->active_mm = NULL; /* for sanity */
115 cpu = smp_processor_id();
116 DBG("CPU%d offline\n", cpu);
117 generic_set_cpu_dead(cpu);
120 /* We don't want to take decrementer interrupts while we are offline,
121 * so clear LPCR:PECE1. We keep PECE2 enabled.
123 mtspr(SPRN_LPCR, mfspr(SPRN_LPCR) & ~(u64)LPCR_PECE1);
124 while (!generic_check_cpu_restart(cpu)) {
126 if (!generic_check_cpu_restart(cpu)) {
127 DBG("CPU%d Unexpected exit while offline !\n", cpu);
128 /* We may be getting an IPI, so we re-enable
129 * interrupts to process it, it will be ignored
130 * since we aren't online (hopefully)
136 mtspr(SPRN_LPCR, mfspr(SPRN_LPCR) | LPCR_PECE1);
137 DBG("CPU%d coming online...\n", cpu);
140 #endif /* CONFIG_HOTPLUG_CPU */
142 static struct smp_ops_t pnv_smp_ops = {
143 .message_pass = smp_muxed_ipi_message_pass,
144 .cause_ipi = NULL, /* Filled at runtime by xics_smp_probe() */
145 .probe = xics_smp_probe,
146 .kick_cpu = pnv_smp_kick_cpu,
147 .setup_cpu = pnv_smp_setup_cpu,
148 .cpu_bootable = pnv_smp_cpu_bootable,
149 #ifdef CONFIG_HOTPLUG_CPU
150 .cpu_disable = pnv_smp_cpu_disable,
151 .cpu_die = generic_cpu_die,
152 #endif /* CONFIG_HOTPLUG_CPU */
155 /* This is called very early during platform setup_arch */
156 void __init pnv_smp_init(void)
158 smp_ops = &pnv_smp_ops;
160 /* XXX We don't yet have a proper entry point from HAL, for
161 * now we rely on kexec-style entry from BML
164 #ifdef CONFIG_PPC_RTAS
165 /* Non-lpar has additional take/give timebase */
166 if (rtas_token("freeze-time-base") != RTAS_UNKNOWN_SERVICE) {
167 smp_ops->give_timebase = rtas_give_timebase;
168 smp_ops->take_timebase = rtas_take_timebase;
170 #endif /* CONFIG_PPC_RTAS */
172 #ifdef CONFIG_HOTPLUG_CPU
173 ppc_md.cpu_die = pnv_smp_cpu_kill_self;