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powerpc: Use one common impl. of RTAS timebase sync and use raw spinlock

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Several platforms use their own copy of what is essentially the same code,
using RTAS to synchronize the timebases when bringing up new CPUs. This
moves it all into a single common implementation and additionally
turns the spinlock into a raw spinlock since the former can rely on
the timebase not being frozen when spinlock debugging is enabled, and finally
masks interrupts while the timebase is disabled.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This commit is contained in:
Benjamin Herrenschmidt 2009-06-16 16:42:50 +00:00
parent f97bb36f70
commit c4007a2fbf
5 changed files with 40 additions and 87 deletions
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3
arch/powerpc/include/asm/rtas.h
View File

@ -245,5 +245,8 @@ static inline u32 rtas_config_addr(int busno, int devfn, int reg)
(devfn << 8) | (reg & 0xff);
}
extern void __cpuinit rtas_give_timebase(void);
extern void __cpuinit rtas_take_timebase(void);
#endif /* __KERNEL__ */
#endif /* _POWERPC_RTAS_H */

31
arch/powerpc/kernel/rtas.c
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@ -38,6 +38,7 @@
#include <asm/syscalls.h>
#include <asm/smp.h>
#include <asm/atomic.h>
#include <asm/time.h>
struct rtas_t rtas = {
.lock = __RAW_SPIN_LOCK_UNLOCKED
@ -971,3 +972,33 @@ int __init early_init_dt_scan_rtas(unsigned long node,
/* break now */
return 1;
}
static raw_spinlock_t timebase_lock;
static u64 timebase = 0;
void __cpuinit rtas_give_timebase(void)
{
unsigned long flags;
local_irq_save(flags);
hard_irq_disable();
__raw_spin_lock(&timebase_lock);
rtas_call(rtas_token("freeze-time-base"), 0, 1, NULL);
timebase = get_tb();
__raw_spin_unlock(&timebase_lock);
while (timebase)
barrier();
rtas_call(rtas_token("thaw-time-base"), 0, 1, NULL);
local_irq_restore(flags);
}
void __cpuinit rtas_take_timebase(void)
{
while (!timebase)
barrier();
__raw_spin_lock(&timebase_lock);
set_tb(timebase >> 32, timebase & 0xffffffff);
timebase = 0;
__raw_spin_unlock(&timebase_lock);
}

30
arch/powerpc/platforms/cell/smp.c
View File

@ -36,7 +36,6 @@
#include <asm/prom.h>
#include <asm/smp.h>
#include <asm/paca.h>
#include <asm/time.h>
#include <asm/machdep.h>
#include <asm/cputable.h>
#include <asm/firmware.h>
@ -140,31 +139,6 @@ static void __devinit smp_cell_setup_cpu(int cpu)
mtspr(SPRN_DABRX, DABRX_KERNEL | DABRX_USER);
}
static DEFINE_SPINLOCK(timebase_lock);
static unsigned long timebase = 0;
static void __devinit cell_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 cell_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_cell_kick_cpu(int nr)
{
BUG_ON(nr < 0 || nr >= NR_CPUS);
@ -224,8 +198,8 @@ void __init smp_init_cell(void)
/* Non-lpar has additional take/give timebase */
if (rtas_token("freeze-time-base") != RTAS_UNKNOWN_SERVICE) {
smp_ops->give_timebase = cell_give_timebase;
smp_ops->take_timebase = cell_take_timebase;
smp_ops->give_timebase = rtas_give_timebase;
smp_ops->take_timebase = rtas_take_timebase;
}
DBG(" <- smp_init_cell()\n");

33
arch/powerpc/platforms/chrp/smp.c
View File

@ -26,7 +26,6 @@
#include <asm/io.h>
#include <asm/prom.h>
#include <asm/smp.h>
#include <asm/time.h>
#include <asm/machdep.h>
#include <asm/mpic.h>
#include <asm/rtas.h>
@ -42,40 +41,12 @@ static void __devinit smp_chrp_setup_cpu(int cpu_nr)
mpic_setup_this_cpu();
}
static DEFINE_SPINLOCK(timebase_lock);
static unsigned int timebase_upper = 0, timebase_lower = 0;
void __devinit smp_chrp_give_timebase(void)
{
spin_lock(&timebase_lock);
rtas_call(rtas_token("freeze-time-base"), 0, 1, NULL);
timebase_upper = get_tbu();
timebase_lower = get_tbl();
spin_unlock(&timebase_lock);
while (timebase_upper || timebase_lower)
barrier();
rtas_call(rtas_token("thaw-time-base"), 0, 1, NULL);
}
void __devinit smp_chrp_take_timebase(void)
{
while (!(timebase_upper || timebase_lower))
barrier();
spin_lock(&timebase_lock);
set_tb(timebase_upper, timebase_lower);
timebase_upper = 0;
timebase_lower = 0;
spin_unlock(&timebase_lock);
printk("CPU %i taken timebase\n", smp_processor_id());
}
/* CHRP with openpic */
struct smp_ops_t chrp_smp_ops = {
.message_pass = smp_mpic_message_pass,
.probe = smp_mpic_probe,
.kick_cpu = smp_chrp_kick_cpu,
.setup_cpu = smp_chrp_setup_cpu,
.give_timebase = smp_chrp_give_timebase,
.take_timebase = smp_chrp_take_timebase,
.give_timebase = rtas_give_timebase,
.take_timebase = rtas_take_timebase,
};

30
arch/powerpc/platforms/pseries/smp.c
View File

@ -35,7 +35,6 @@
#include <asm/prom.h>
#include <asm/smp.h>
#include <asm/paca.h>
#include <asm/time.h>
#include <asm/machdep.h>
#include <asm/cputable.h>
#include <asm/firmware.h>
@ -118,31 +117,6 @@ static void __devinit smp_xics_setup_cpu(int cpu)
}
#endif /* CONFIG_XICS */
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);
@ -209,8 +183,8 @@ static void __init smp_init_pseries(void)
/* 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;
smp_ops->give_timebase = rtas_give_timebase;
smp_ops->take_timebase = rtas_take_timebase;
}
pr_debug(" <- smp_init_pSeries()\n");