/*
* 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.
*/
#include <linux/kernel.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/device.h>
#include <linux/cpu.h>
#include <asm/ptrace.h>
#include <linux/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/machdep.h>
#include <asm/cputable.h>
#include <asm/firmware.h>
#include <asm/rtas.h>
#include <asm/mpic.h>
#include <asm/vdso_datapage.h>
#include <asm/cputhreads.h>
#include <asm/xics.h>
#include <asm/dbell.h>
#include <asm/plpar_wrappers.h>
#include "pseries.h"
#include "offline_states.h"
/*
* The Primary thread of each non-boot processor was started from the OF client
* interface by prom_hold_cpus and is spinning on secondary_hold_spinloop.
*/
static cpumask_var_t of_spin_mask;
/*
* If we multiplex IPI mechanisms, store the appropriate XICS IPI mechanism here
*/
static void (*xics_cause_ipi)(int cpu, unsigned long data);
/* Query where a cpu is now. Return codes #defined in plpar_wrappers.h */
int smp_query_cpu_stopped(unsigned int pcpu)
{
int cpu_status, status;
int qcss_tok = rtas_token("query-cpu-stopped-state");
if (qcss_tok == RTAS_UNKNOWN_SERVICE) {
printk_once(KERN_INFO
"Firmware doesn't support query-cpu-stopped-state\n");
return QCSS_HARDWARE_ERROR;
}
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;
}
/**
* 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 smp_startup_cpu(unsigned int lcpu)
{
int status;
unsigned long start_here = __pa((u32)*((unsigned long *)
generic_secondary_smp_init));
unsigned int pcpu;
int start_cpu;
if (cpumask_test_cpu(lcpu, of_spin_mask))
/* Already started by OF and sitting in spin loop */
return 1;
pcpu = get_hard_smp_processor_id(lcpu);
/* Check to see if the CPU out of FW already for kexec */
if (smp_query_cpu_stopped(pcpu) == QCSS_NOT_STOPPED){
cpumask_set_cpu(lcpu, of_spin_mask);
return 1;
}
/* Fixup atomic count: it exited inside IRQ handler. */
task_thread_info(paca[lcpu].__current)->preempt_count = 0;
#ifdef CONFIG_HOTPLUG_CPU
if (get_cpu_current_state(lcpu) == CPU_STATE_INACTIVE)
goto out;
#endif
/*
* If the RTAS start-cpu token does not exist then presume the
* cpu is already spinning.
*/
start_cpu = rtas_token("start-cpu");
if (start_cpu == RTAS_UNKNOWN_SERVICE)
return 1;
status = rtas_call(start_cpu, 3, 1, NULL, pcpu, start_here, pcpu);
if (status != 0) {
printk(KERN_ERR "start-cpu failed: %i\n", status);
return 0;
}
#ifdef CONFIG_HOTPLUG_CPU
out:
#endif
return 1;
}
static void smp_xics_setup_cpu(int cpu)
{
if (cpu != boot_cpuid)
xics_setup_cpu();
if (cpu_has_feature(CPU_FTR_DBELL))
doorbell_setup_this_cpu();
if (firmware_has_feature(FW_FEATURE_SPLPAR))
vpa_init(cpu);
cpumask_clear_cpu(cpu, of_spin_mask);
#ifdef CONFIG_HOTPLUG_CPU
set_cpu_current_state(cpu, CPU_STATE_ONLINE);
set_default_offline_state(cpu);
#endif
}
static int smp_pSeries_kick_cpu(int nr)
{
BUG_ON(nr < 0 || nr >= NR_CPUS);
if (!smp_startup_cpu(nr))
return -ENOENT;
/*
* 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;
#ifdef CONFIG_HOTPLUG_CPU
set_preferred_offline_state(nr, CPU_STATE_ONLINE);
if (get_cpu_current_state(nr) == CPU_STATE_INACTIVE) {
long rc;
unsigned long hcpuid;
hcpuid = get_hard_smp_processor_id(nr);
rc = plpar_hcall_norets(H_PROD, hcpuid);
if (rc != H_SUCCESS)
printk(KERN_ERR "Error: Prod to wake up processor %d "
"Ret= %ld\n", nr, rc);
}
#endif
return 0;
}
/* Only used on systems that support multiple IPI mechanisms */
static void pSeries_cause_ipi_mux(int cpu, unsigned long data)
{
if (cpumask_test_cpu(cpu, cpu_sibling_mask(smp_processor_id())))
doorbell_cause_ipi(cpu, data);
else
xics_cause_ipi(cpu, data);
}
static __init int pSeries_smp_probe(void)
{
int ret = xics_smp_probe();
if (cpu_has_feature(CPU_FTR_DBELL)) {
xics_cause_ipi = smp_ops->cause_ipi;
smp_ops->cause_ipi = pSeries_cause_ipi_mux;
}
return ret;
}
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 = NULL, /* Use smp_muxed_ipi_message_pass */
.cause_ipi = NULL, /* Filled at runtime by pSeries_smp_probe() */
.probe = pSeries_smp_probe,
.kick_cpu = smp_pSeries_kick_cpu,
.setup_cpu = smp_xics_setup_cpu,
.cpu_bootable = smp_generic_cpu_bootable,
};
/* This is called very early */
static void __init smp_init_pseries(void)
{
int i;
pr_debug(" -> smp_init_pSeries()\n");
alloc_bootmem_cpumask_var(&of_spin_mask);
/*
* Mark threads which are still spinning in hold loops
*
* We know prom_init will not have started them if RTAS supports
* query-cpu-stopped-state.
*/
if (rtas_token("query-cpu-stopped-state") == RTAS_UNKNOWN_SERVICE) {
if (cpu_has_feature(CPU_FTR_SMT)) {
for_each_present_cpu(i) {
if (cpu_thread_in_core(i) == 0)
cpumask_set_cpu(i, of_spin_mask);
}
} else
cpumask_copy(of_spin_mask, cpu_present_mask);
cpumask_clear_cpu(boot_cpuid, of_spin_mask);
}
/* 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;
}
pr_debug(" <- smp_init_pSeries()\n");
}
void __init smp_init_pseries_mpic(void)
{
smp_ops = &pSeries_mpic_smp_ops;
smp_init_pseries();
}
void __init smp_init_pseries_xics(void)
{
smp_ops = &pSeries_xics_smp_ops;
smp_init_pseries();
}
