m68k: mvme147: Handle timer counter overflow

[linux-2.6-microblaze.git] / arch / m68k / mvme147 / config.c

diff --git a/arch/m68k/mvme147/config.c b/arch/m68k/mvme147/config.c
index c44a254..545a1fe 100644 (file)
--- a/arch/m68k/mvme147/config.c
+++ b/arch/m68k/mvme147/config.c
@@ -118,7 +118,7 @@ static irqreturn_t mvme147_timer_int (int irq, void *dev_id)
 
        local_irq_save(flags);
        m147_pcc->t1_int_cntrl = PCC_TIMER_INT_CLR;
-       m147_pcc->t1_int_cntrl = PCC_INT_ENAB|PCC_LEVEL_TIMER1;
+       m147_pcc->t1_cntrl = PCC_TIMER_CLR_OVF;
        clk_total += PCC_TIMER_CYCLES;
        timer_routine(0, NULL);
        local_irq_restore(flags);
@@ -144,21 +144,22 @@ void mvme147_sched_init (irq_handler_t timer_routine)
        clocksource_register_hz(&mvme147_clk, PCC_TIMER_CLOCK_FREQ);
 }
 
-/* XXX There are race hazards in this code XXX */
 static u64 mvme147_read_clk(struct clocksource *cs)
 {
        unsigned long flags;
-       volatile unsigned short *cp = (volatile unsigned short *)0xfffe1012;
-       unsigned short n;
+       u8 overflow, tmp;
+       u16 count;
        u32 ticks;
 
        local_irq_save(flags);
-       n = *cp;
-       while (n != *cp)
-               n = *cp;
-
-       n -= PCC_TIMER_PRELOAD;
-       ticks = clk_total + n;
+       tmp = m147_pcc->t1_cntrl >> 4;
+       count = m147_pcc->t1_count;
+       overflow = m147_pcc->t1_cntrl >> 4;
+       if (overflow != tmp)
+               count = m147_pcc->t1_count;
+       count -= PCC_TIMER_PRELOAD;
+       ticks = count + overflow * PCC_TIMER_CYCLES;
+       ticks += clk_total;
        local_irq_restore(flags);
 
        return ticks;