/*
* SMP support for pSeries machines.
*
* Dave Engebretsen, Peter Bergner, and
* Mike Corrigan {engebret|bergner|mikec}@us.ibm.com
*
* Plus various changes from other IBM teams...
*
* 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.
*/
#undef DEBUG
#include <linux/config.h>
#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/cache.h>
#include <linux/err.h>
#include <linux/sysdev.h>
#include <linux/cpu.h>
#include <asm/ptrace.h>
#include <asm/atomic.h>
#include <asm/irq.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/io.h>
#include <asm/prom.h>
#include <asm/smp.h>
#include <asm/paca.h>
#include <asm/time.h>
#include <asm/machdep.h>
#include <asm/xics.h>
#include <asm/cputable.h>
#include <asm/system.h>
#include <asm/rtas.h>
#include <asm/plpar_wrappers.h>
#include <asm/pSeries_reconfig.h>
#include "mpic.h"
#ifdef DEBUG
#define DBG(fmt...) udbg_printf(fmt)
#else
#define DBG(fmt...)
#endif
/*
* The primary thread of each non-boot processor is recorded here before
* smp init.
*/
static cpumask_t of_spin_map;
extern void pSeries_secondary_smp_init(unsigned long);
#ifdef CONFIG_HOTPLUG_CPU
/* Get state of physical CPU.
* Return codes:
* 0 - The processor is in the RTAS stopped state
* 1 - stop-self is in progress
* 2 - The processor is not in the RTAS stopped state
* -1 - Hardware Error
* -2 - Hardware Busy, Try again later.
*/
static int query_cpu_stopped(unsigned int pcpu)
{
int cpu_status;
int status, qcss_tok;
qcss_tok = rtas_token("query-cpu-stopped-state");
if (qcss_tok == RTAS_UNKNOWN_SERVICE)
return -1;
status = rtas_call(qcss_tok, 1, 2, &cpu_status, pcpu);
if (status != 0) {
printk(KERN_ERR
"RTAS query-cpu-stopped-state failed: %i\n", status);
return status;
}
return cpu_status;
}
int pSeries_cpu_disable(void)
{
systemcfg->processorCount--;
/*fix boot_cpuid here*/
if (smp_processor_id() == boot_cpuid)
boot_cpuid = any_online_cpu(cpu_online_map);
/* FIXME: abstract this to not be platform specific later on */
xics_migrate_irqs_away();
return 0;
}
void pSeries_cpu_die(unsigned int cpu)
{
int tries;
int cpu_status;
unsigned int pcpu = get_hard_smp_processor_id(cpu);
for (tries = 0; tries < 25; tries++) {
cpu_status = query_cpu_stopped(pcpu);
if (cpu_status == 0 || cpu_status == -1)
break;
msleep(200);
}
if (cpu_status != 0) {
printk("Querying DEAD? cpu %i (%i) shows %i\n",
cpu, pcpu, cpu_status);
}
/* Isolation and deallocation are definatly done by
* drslot_chrp_cpu. If they were not they would be
* done here. Change isolate state to Isolate and
* change allocation-state to Unusable.
*/
paca[cpu].cpu_start = 0;
}
/*
* Update cpu_present_map and paca(s) for a new cpu node. The wrinkle
* here is that a cpu device node may represent up to two logical cpus
* in the SMT case. We must honor the assumption in other code that
* the logical ids for sibling SMT threads x and y are adjacent, such
* that x^1 == y and y^1 == x.
*/
static int pSeries_add_processor(struct device_node *np)
{
unsigned int cpu;
cpumask_t candidate_map, tmp = CPU_MASK_NONE;
int err = -ENOSPC, len, nthreads, i;
u32 *intserv;
intserv = (u32 *)get_property(np, "ibm,ppc-interrupt-server#s", &len);
if (!intserv)
return 0;
nthreads = len / sizeof(u32);
for (i = 0; i < nthreads; i++)
cpu_set(i, tmp);
lock_cpu_hotplug();
BUG_ON(!cpus_subset(cpu_present_map, cpu_possible_map));
/* Get a bitmap of unoccupied slots. */
cpus_xor(candidate_map, cpu_possible_map, cpu_present_map);
if (cpus_empty(candidate_map)) {
/* If we get here, it most likely means that NR_CPUS is
* less than the partition's max processors setting.
*/
printk(KERN_ERR "Cannot add cpu %s; this system configuration"
" supports %d logical cpus.\n", np->full_name,
cpus_weight(cpu_possible_map));
goto out_unlock;
}
while (!cpus_empty(tmp))
if (cpus_subset(tmp, candidate_map))
/* Found a range where we can insert the new cpu(s) */
break;
else
cpus_shift_left(tmp, tmp, nthreads);
if (cpus_empty(tmp)) {
printk(KERN_ERR "Unable to find space in cpu_present_map for"
" processor %s with %d thread(s)\n", np->name,
nthreads);
goto out_unlock;
}
for_each_cpu_mask(cpu, tmp) {
BUG_ON(cpu_isset(cpu, cpu_present_map));
cpu_set(cpu, cpu_present_map);
set_hard_smp_processor_id(cpu, *intserv++);
}
err = 0;
out_unlock:
unlock_cpu_hotplug();
return err;
}
/*
* Update the present map for a cpu node which is going away, and set
* the hard id in the paca(s) to -1 to be consistent with boot time
* convention for non-present cpus.
*/
static void pSeries_remove_processor(struct device_node *np)
{
unsigned int cpu;
int len, nthreads, i;
u32 *intserv;
intserv = (u32 *)get_property(np, "ibm,ppc-interrupt-server#s", &len);
if (!intserv)
return;
nthreads = len / sizeof(u32);
lock_cpu_hotplug();
for (i = 0; i < nthreads; i++) {
for_each_present_cpu(cpu) {
if (get_hard_smp_processor_id(cpu) != intserv[i])
continue;
BUG_ON(cpu_online(cpu));
cpu_clear(cpu, cpu_present_map);
set_hard_smp_processor_id(cpu, -1);
break;
}
if (cpu == NR_CPUS)
printk(KERN_WARNING "Could not find cpu to remove "
"with physical id 0x%x\n", intserv[i]);
}
unlock_cpu_hotplug();
}
static int pSeries_smp_notifier(struct notifier_block *nb, unsigned long action, void *node)
{
int err = NOTIFY_OK;
switch (action) {
case PSERIES_RECONFIG_ADD:
if (pSeries_add_processor(node))
err = NOTIFY_BAD;
break;
case PSERIES_RECONFIG_REMOVE:
pSeries_remove_processor(node);
break;
default:
err = NOTIFY_DONE;
break;
}
return err;
}
static struct notifier_block pSeries_smp_nb = {
.notifier_call = pSeries_smp_notifier,
};
#endif /* CONFIG_HOTPLUG_CPU */
/**
* smp_startup_cpu() - start the given cpu
*
* At boot time, there is nothing to do for primary threads which were
* started from Open Firmware. For anything else, call RTAS with the
* appropriate start location.
*
* Returns:
* 0 - failure
* 1 - success
*/
static inline int __devinit smp_startup_cpu(unsigned int lcpu)
{
int status;
unsigned long start_here = __pa((u32)*((unsigned long *)
pSeries_secondary_smp_init));
unsigned int pcpu;
if (cpu_isset(lcpu, of_spin_map))
/* Already started by OF and sitting in spin loop */
return 1;
pcpu = get_hard_smp_processor_id(lcpu);
/* Fixup atomic count: it exited inside IRQ handler. */
paca[lcpu].__current->thread_info->preempt_count = 0;
status = rtas_call(rtas_token("start-cpu"), 3, 1, NULL,
pcpu, start_here, lcpu);
if (status != 0) {
printk(KERN_ERR "start-cpu failed: %i\n", status);
return 0;
}
return 1;
}
static inline void smp_xics_do_message(int cpu, int msg)
{
set_bit(msg, &xics_ipi_message[cpu].value);
mb();
xics_cause_IPI(cpu);
}
static void smp_xics_message_pass(int target, int msg)
{
unsigned int i;
if (target < NR_CPUS) {
smp_xics_do_message(target, msg);
} else {
for_each_online_cpu(i) {
if (target == MSG_ALL_BUT_SELF
&& i == smp_processor_id())
continue;
smp_xics_do_message(i, msg);
}
}
}
static int __init smp_xics_probe(void)
{
xics_request_IPIs();
return cpus_weight(cpu_possible_map);
}
static void __devinit smp_xics_setup_cpu(int cpu)
{
if (cpu != boot_cpuid)
xics_setup_cpu();
if (cur_cpu_spec->firmware_features & FW_FEATURE_SPLPAR)
vpa_init(cpu);
cpu_clear(cpu, of_spin_map);
}
static DEFINE_SPINLOCK(timebase_lock);
static unsigned long timebase = 0;
static void __devinit pSeries_give_timebase(void)
{
spin_lock(&timebase_lock);
rtas_call(rtas_token("freeze-time-base"), 0, 1, NULL);
timebase = get_tb();
spin_unlock(&timebase_lock);
while (timebase)
barrier();
rtas_call(rtas_token("thaw-time-base"), 0, 1, NULL);
}
static void __devinit pSeries_take_timebase(void)
{
while (!timebase)
barrier();
spin_lock(&timebase_lock);
set_tb(timebase >> 32, timebase & 0xffffffff);
timebase = 0;
spin_unlock(&timebase_lock);
}
static void __devinit smp_pSeries_kick_cpu(int nr)
{
BUG_ON(nr < 0 || nr >= NR_CPUS);
if (!smp_startup_cpu(nr))
return;
/*
* The processor is currently spinning, waiting for the
* cpu_start field to become non-zero After we set cpu_start,
* the processor will continue on to secondary_start
*/
paca[nr].cpu_start = 1;
}
static int smp_pSeries_cpu_bootable(unsigned int nr)
{
/* Special case - we inhibit secondary thread startup
* during boot if the user requests it. Odd-numbered
* cpus are assumed to be secondary threads.
*/
if (system_state < SYSTEM_RUNNING &&
cpu_has_feature(CPU_FTR_SMT) &&
!smt_enabled_at_boot && nr % 2 != 0)
return 0;
return 1;
}
static struct smp_ops_t pSeries_mpic_smp_ops = {
.message_pass = smp_mpic_message_pass,
.probe = smp_mpic_probe,
.kick_cpu = smp_pSeries_kick_cpu,
.setup_cpu = smp_mpic_setup_cpu,
};
static struct smp_ops_t pSeries_xics_smp_ops = {
.message_pass = smp_xics_message_pass,
.probe = smp_xics_probe,
.kick_cpu = smp_pSeries_kick_cpu,
.setup_cpu = smp_xics_setup_cpu,
.cpu_bootable = smp_pSeries_cpu_bootable,
};
/* This is called very early */
void __init smp_init_pSeries(void)
{
int i;
DBG(" -> smp_init_pSeries()\n");
if (ppc64_interrupt_controller == IC_OPEN_PIC)
smp_ops = &pSeries_mpic_smp_ops;
else
smp_ops = &pSeries_xics_smp_ops;
#ifdef CONFIG_HOTPLUG_CPU
smp_ops->cpu_disable = pSeries_cpu_disable;
smp_ops->cpu_die = pSeries_cpu_die;
/* Processors can be added/removed only on LPAR */
if (systemcfg->platform == PLATFORM_PSERIES_LPAR)
pSeries_reconfig_notifier_register(&pSeries_smp_nb);
#endif
/* Mark threads which are still spinning in hold loops. */
if (cpu_has_feature(CPU_FTR_SMT)) {
for_each_present_cpu(i) {
if (i % 2 == 0)
/*
* Even-numbered logical cpus correspond to
* primary threads.
*/
cpu_set(i, of_spin_map);
}
} else {
of_spin_map = cpu_present_map;
}
cpu_clear(boot_cpuid, of_spin_map);
/* Non-lpar has additional take/give timebase */
if (rtas_token("freeze-time-base") != RTAS_UNKNOWN_SERVICE) {
smp_ops->give_timebase = pSeries_give_timebase;
smp_ops->take_timebase = pSeries_take_timebase;
}
DBG(" <- smp_init_pSeries()\n");
}
