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

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>

diff --git a/arch/powerpc/include/asm/rtas.h b/arch/powerpc/include/asm/rtas.h
index 0af42d20b692a7cffb094afc731dc1c90d5a98b3..168fce726201d3799fc3878e3a7620e1575a6dfd 100644 (file)
--- a/arch/powerpc/include/asm/rtas.h
+++ b/arch/powerpc/include/asm/rtas.h
@@ -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 */

diff --git a/arch/powerpc/kernel/rtas.c b/arch/powerpc/kernel/rtas.c
index d9a9974c69389539aea8898acf5bf58310bdccc6..c434823b8c83a02b9ccd161e2e22bea1c52a1c65 100644 (file)
--- a/arch/powerpc/kernel/rtas.c
+++ b/arch/powerpc/kernel/rtas.c
@@ -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);
+}

diff --git a/arch/powerpc/platforms/cell/smp.c b/arch/powerpc/platforms/cell/smp.c
index 9046803c827670a273c5b43d13cee1367ffa16fe..bc97fada48c664662ee59808c9f6424820d42f6a 100644 (file)
--- a/arch/powerpc/platforms/cell/smp.c
+++ b/arch/powerpc/platforms/cell/smp.c
@@ -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");

diff --git a/arch/powerpc/platforms/chrp/smp.c b/arch/powerpc/platforms/chrp/smp.c
index 10a4a4d063b6411b04db150f4bd00980aa67a6ee..02cafecc90e32b9562adf267dd689d742605abc3 100644 (file)
--- a/arch/powerpc/platforms/chrp/smp.c
+++ b/arch/powerpc/platforms/chrp/smp.c
@@ -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,
 };

diff --git a/arch/powerpc/platforms/pseries/smp.c b/arch/powerpc/platforms/pseries/smp.c
index 1a231c389ba0122ce7f55419962af8a1bbdab25f..1f8f6cfb94f7f504b4f44f025fc02b600b392000 100644 (file)
--- a/arch/powerpc/platforms/pseries/smp.c
+++ b/arch/powerpc/platforms/pseries/smp.c
@@ -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");