[ARM] 3384/1: AT91RM9200: Timer

Patch from Andrew Victor

If the timer interrupt is ever significantly delayed (or after the
system was suspended), the system could spin incrementing the time for
too long.
The fix is to replace the "do {} while" with a "while {}".

Orignal patch by Savin Zlobec and Peter Menzebach.

Signed-off-by: Andrew Victor <andrew@sanpeople.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

diff --git a/arch/arm/mach-at91rm9200/time.c b/arch/arm/mach-at91rm9200/time.c
index 1b6dd2d..7ffcf44 100644 (file)
--- a/arch/arm/mach-at91rm9200/time.c
+++ b/arch/arm/mach-at91rm9200/time.c
@@ -71,11 +71,11 @@ static irqreturn_t at91rm9200_timer_interrupt(int irq, void *dev_id, struct pt_r
        if (at91_sys_read(AT91_ST_SR) & AT91_ST_PITS) { /* This is a shared interrupt */
                write_seqlock(&xtime_lock);
 
-               do {
+               while (((read_CRTR() - at91_sys_read(AT91_ST_RTAR)) & AT91_ST_ALMV) >= LATCH) {
                        timer_tick(regs);
                        rtar = (at91_sys_read(AT91_ST_RTAR) + LATCH) & AT91_ST_ALMV;
                        at91_sys_write(AT91_ST_RTAR, rtar);
-               } while (((read_CRTR() - at91_sys_read(AT91_ST_RTAR)) & AT91_ST_ALMV) >= LATCH);
+               }
 
                write_sequnlock(&xtime_lock);