- patches.fixes/patch-2.6.11-rc1: 2.6.11-rc1.

[linux-flexiantxendom0-3.2.10.git] / arch / arm / mach-ixp2000 / core.c

diff --git a/arch/arm/mach-ixp2000/core.c b/arch/arm/mach-ixp2000/core.c
index 0b59703..4b26341 100644 (file)
--- a/arch/arm/mach-ixp2000/core.c
+++ b/arch/arm/mach-ixp2000/core.c
@@ -167,15 +167,15 @@ void __init ixp2000_map_io(void)
  *************************************************************************/
 static unsigned ticks_per_jiffy;
 static unsigned ticks_per_usec;
+static unsigned next_jiffy_time;
 
 unsigned long ixp2000_gettimeoffset (void)
 {
-       unsigned long elapsed;
+       unsigned long offset;
 
-       /* Get ticks since last perfect jiffy */
-       elapsed = ticks_per_jiffy - *IXP2000_T1_CSR;
+       offset = next_jiffy_time - *IXP2000_T4_CSR;
 
-       return elapsed / ticks_per_usec;
+       return offset / ticks_per_usec;
 }
 
 static int ixp2000_timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
@@ -185,7 +185,10 @@ static int ixp2000_timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
        /* clear timer 1 */
        ixp2000_reg_write(IXP2000_T1_CLR, 1);
        
-       timer_tick(regs);
+       while ((next_jiffy_time - *IXP2000_T4_CSR) > ticks_per_jiffy) {
+               timer_tick(regs);
+               next_jiffy_time -= ticks_per_jiffy;
+       }
 
        write_sequnlock(&xtime_lock);
 
@@ -201,7 +204,7 @@ static struct irqaction ixp2000_timer_irq = {
 void __init ixp2000_init_time(unsigned long tick_rate)
 {
        ixp2000_reg_write(IXP2000_T1_CLR, 0);
-       ixp2000_reg_write(IXP2000_T2_CLR, 0);
+       ixp2000_reg_write(IXP2000_T4_CLR, 0);
 
        ticks_per_jiffy = (tick_rate + HZ/2) / HZ;
        ticks_per_usec = tick_rate / 1000000;
@@ -209,6 +212,13 @@ void __init ixp2000_init_time(unsigned long tick_rate)
        ixp2000_reg_write(IXP2000_T1_CLD, ticks_per_jiffy);
        ixp2000_reg_write(IXP2000_T1_CTL, (1 << 7));
 
+       /*
+        * We use T4 as a monotonic counter to track missed jiffies
+        */
+       ixp2000_reg_write(IXP2000_T4_CLD, -1);
+       ixp2000_reg_write(IXP2000_T4_CTL, (1 << 7));
+       next_jiffy_time = 0xffffffff - ticks_per_jiffy;
+
        /* register for interrupt */
        setup_irq(IRQ_IXP2000_TIMER1, &ixp2000_timer_irq);
 }