[POWERPC] pasemi: SMP timebase sync

Timebase update is simple on PA6T, since global updates can be done from
one core by writing to an SPR.

Signed-off-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Paul Mackerras <paulus@samba.org>

2 files changed, 31 insertions, 2 deletions

diff --git a/arch/powerpc/platforms/pasemi/setup.c b/arch/powerpc/platforms/pasemi/setup.c
index cabf7017c05e..2d9652b6acb3 100644
--- a/arch/powerpc/platforms/pasemi/setup.c
+++ b/arch/powerpc/platforms/pasemi/setup.c
@@ -48,13 +48,36 @@ static void pas_restart(char *cmd)
 }
 
 #ifdef CONFIG_SMP
+static DEFINE_SPINLOCK(timebase_lock);
+
+static void __devinit pas_give_timebase(void)
+{
+        unsigned long tb;
+
+        spin_lock(&timebase_lock);
+        mtspr(SPRN_TBCTL, TBCTL_FREEZE);
+        tb = mftb();
+        mtspr(SPRN_TBCTL, TBCTL_UPDATE_LOWER | (tb & 0xffffffff));
+        mtspr(SPRN_TBCTL, TBCTL_UPDATE_UPPER | (tb >> 32));
+        mtspr(SPRN_TBCTL, TBCTL_RESTART);
+        spin_unlock(&timebase_lock);
+        pr_debug("pas_give_timebase: cpu %d gave tb %lx\n",
+                 smp_processor_id(), tb);
+}
+
+static void __devinit pas_take_timebase(void)
+{
+        pr_debug("pas_take_timebase: cpu %d has tb %lx\n",
+                 smp_processor_id(), mftb());
+}
+
 struct smp_ops_t pas_smp_ops = {
         .probe          = smp_mpic_probe,
         .message_pass   = smp_mpic_message_pass,
         .kick_cpu       = smp_generic_kick_cpu,
         .setup_cpu      = smp_mpic_setup_cpu,
-        .give_timebase  = smp_generic_give_timebase,
-        .take_timebase  = smp_generic_take_timebase,
+        .give_timebase  = pas_give_timebase,
+        .take_timebase  = pas_take_timebase,
 };
 #endif /* CONFIG_SMP */
 
diff --git a/include/asm-powerpc/reg.h b/include/asm-powerpc/reg.h
index 923df6ceaa5c..0d7f0164ed81 100644
--- a/include/asm-powerpc/reg.h
+++ b/include/asm-powerpc/reg.h
@@ -392,6 +392,12 @@
 #define SPRN_HSRR0      0x13A   /* Save/Restore Register 0 */
 #define SPRN_HSRR1      0x13B   /* Save/Restore Register 1 */
 
+#define SPRN_TBCTL      0x35f   /* PA6T Timebase control register */
+#define   TBCTL_FREEZE          0x0000000000000000ull /* Freeze all tbs */
+#define   TBCTL_RESTART         0x0000000100000000ull /* Restart all tbs */
+#define   TBCTL_UPDATE_UPPER    0x0000000200000000ull /* Set upper 32 bits */
+#define   TBCTL_UPDATE_LOWER    0x0000000300000000ull /* Set lower 32 bits */
+
 #ifndef SPRN_SVR
 #define SPRN_SVR        0x11E   /* System Version Register */
 #endif