Timer interrup can not go forward!

[Pete McCormick]

I had a similar problem with 2.4.18 and my 8260 ADS board.  Make sure the
frequencies in the bd_t structure are in Hz, not MHz (the default for
ppcboot?).  I just multiplied by 1000000 instead of rebuilding ppcboot, I think
there is build option you can set for this.

Pete


--- zhongqx <zhongqx at guoguang.com.cn> wrote:
>
> Sir,
>     How are you!
>     I find the problem with my linux-2.4.18 on MPC8xxFADS board ,I find when
> the Start_kernel function in /init/main.c run to Sti(),
> then time_interrupt() start,but it can not be finished,it loop in while loops
> like following ,can not go out from while loops,Do you have
> this probelm? thank you in advance!
>
>
>
>
> int timer_interrupt(struct pt_regs * regs)
> {
>  int next_dec;
>  unsigned long cpu = smp_processor_id();
>  unsigned jiffy_stamp = last_jiffy_stamp(cpu);
>  extern void do_IRQ(struct pt_regs *);
>
>  if (atomic_read(&ppc_n_lost_interrupts) != 0)
>   do_IRQ(regs);
>
>  hardirq_enter(cpu);
>
>  while ((next_dec = tb_ticks_per_jiffy - tb_delta(&jiffy_stamp)) < 0) {
>   jiffy_stamp += tb_ticks_per_jiffy;
>   if (!user_mode(regs))
>    ppc_do_profile(instruction_pointer(regs));
>     if (smp_processor_id())
>    continue;
>
>   /* We are in an interrupt, no need to save/restore flags */
>   write_lock(&xtime_lock);
>   tb_last_stamp = jiffy_stamp;
>   do_timer(regs);
>
>   /*
>    * update the rtc when needed, this should be performed on the
>    * right fraction of a second. Half or full second ?
>    * Full second works on mk48t59 clocks, others need testing.
>    * Note that this update is basically only used through
>    * the adjtimex system calls. Setting the HW clock in
>    * any other way is a /dev/rtc and userland business.
>    * This is still wrong by -0.5/+1.5 jiffies because of the
>    * timer interrupt resolution and possible delay, but here we
>    * hit a quantization limit which can only be solved by higher
>    * resolution timers and decoupling time management from timer
>    * interrupts. This is also wrong on the clocks
>    * which require being written at the half second boundary.
>    * We should have an rtc call that only sets the minutes and
>    * seconds like on Intel to avoid problems with non UTC clocks.
>    */
>   if ( (time_status & STA_UNSYNC) == 0 &&
>        xtime.tv_sec - last_rtc_update >= 659 &&
>        abs(xtime.tv_usec - (1000000-1000000/HZ)) < 500000/HZ &&
>        jiffies - wall_jiffies == 1) {
>      if (ppc_md.set_rtc_time(xtime.tv_sec+1 + time_offset) == 0)
>     last_rtc_update = xtime.tv_sec+1;
>    else
>     /* Try again one minute later */
>     last_rtc_update += 60;
>   }
>   write_unlock(&xtime_lock);
>  }
>  if ( !disarm_decr[smp_processor_id()] )
>   set_dec(next_dec);
>  last_jiffy_stamp(cpu) = jiffy_stamp;
>
> #ifdef CONFIG_SMP
>  smp_local_timer_interrupt(regs);
> #endif /* CONFIG_SMP */
>
>  if (ppc_md.heartbeat && !ppc_md.heartbeat_count--)
>   ppc_md.heartbeat();
>
>  hardirq_exit(cpu);
>
>  if (softirq_pending(cpu))
>   do_softirq();
>
>  return 1; /* lets ret_from_int know we can do checks */
> }
>
>
>


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