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Diffstat (limited to 'arch/mips/kernel/sync-r4k.c')
-rw-r--r--arch/mips/kernel/sync-r4k.c32
1 files changed, 8 insertions, 24 deletions
diff --git a/arch/mips/kernel/sync-r4k.c b/arch/mips/kernel/sync-r4k.c
index 2242bdd43..4472a7f98 100644
--- a/arch/mips/kernel/sync-r4k.c
+++ b/arch/mips/kernel/sync-r4k.c
@@ -17,35 +17,23 @@
#include <asm/barrier.h>
#include <asm/mipsregs.h>
-static atomic_t count_start_flag = ATOMIC_INIT(0);
+static unsigned int initcount = 0;
static atomic_t count_count_start = ATOMIC_INIT(0);
static atomic_t count_count_stop = ATOMIC_INIT(0);
-static atomic_t count_reference = ATOMIC_INIT(0);
#define COUNTON 100
-#define NR_LOOPS 5
+#define NR_LOOPS 3
void synchronise_count_master(int cpu)
{
int i;
unsigned long flags;
- unsigned int initcount;
printk(KERN_INFO "Synchronize counters for CPU %u: ", cpu);
local_irq_save(flags);
/*
- * Notify the slaves that it's time to start
- */
- atomic_set(&count_reference, read_c0_count());
- atomic_set(&count_start_flag, cpu);
- smp_wmb();
-
- /* Count will be initialised to current timer for all CPU's */
- initcount = read_c0_count();
-
- /*
* We loop a few times to get a primed instruction cache,
* then the last pass is more or less synchronised and
* the master and slaves each set their cycle counters to a known
@@ -63,9 +51,13 @@ void synchronise_count_master(int cpu)
atomic_set(&count_count_stop, 0);
smp_wmb();
- /* this lets the slaves write their count register */
+ /* Let the slave writes its count register */
atomic_inc(&count_count_start);
+ /* Count will be initialised to current timer */
+ if (i == 1)
+ initcount = read_c0_count();
+
/*
* Everyone initialises count in the last loop:
*/
@@ -73,7 +65,7 @@ void synchronise_count_master(int cpu)
write_c0_count(initcount);
/*
- * Wait for all slaves to leave the synchronization point:
+ * Wait for slave to leave the synchronization point:
*/
while (atomic_read(&count_count_stop) != 1)
mb();
@@ -83,7 +75,6 @@ void synchronise_count_master(int cpu)
}
/* Arrange for an interrupt in a short while */
write_c0_compare(read_c0_count() + COUNTON);
- atomic_set(&count_start_flag, 0);
local_irq_restore(flags);
@@ -98,19 +89,12 @@ void synchronise_count_master(int cpu)
void synchronise_count_slave(int cpu)
{
int i;
- unsigned int initcount;
/*
* Not every cpu is online at the time this gets called,
* so we first wait for the master to say everyone is ready
*/
- while (atomic_read(&count_start_flag) != cpu)
- mb();
-
- /* Count will be initialised to next expire for all CPU's */
- initcount = atomic_read(&count_reference);
-
for (i = 0; i < NR_LOOPS; i++) {
atomic_inc(&count_count_start);
while (atomic_read(&count_count_start) != 2)