reboot not working on linux-2.6.37 for ARMv7

[shiraz hashim]

Hello Russell,

On Sat, Feb 12, 2011 at 9:51 PM, Russell King - ARM Linux
<linux at arm.linux.org.uk> wrote:
> On Sat, Feb 12, 2011 at 09:45:45PM +0530, viresh kumar wrote:

[...]

>> We are not modifying flush_cache_all. L2 cache is not flushed from there.
>> Actually as soon as L1 Cache is flushed and disabled, spin_lock is taken from
>> some other thread. This creates problem for our platform, as we do not have
>> monitors support at L2 thus failing strex instruction.
>>
>> If we disable L2 then reboot works fine, as expected.
>
> Again, this should not be happening:
>
> void smp_send_stop(void)
> {
>        unsigned long timeout;
>
>        if (num_online_cpus() > 1) {
>                cpumask_t mask = cpu_online_map;
>                cpu_clear(smp_processor_id(), mask);
>
>                smp_cross_call(&mask, IPI_CPU_STOP);
>        }
>
>        /* Wait up to one second for other CPUs to stop */
>        timeout = USEC_PER_SEC;
>        while (num_online_cpus() > 1 && timeout--)
>                udelay(1);
>
>        if (num_online_cpus() > 1)
>                pr_warning("SMP: failed to stop secondary CPUs\n");
> }
>
> void machine_shutdown(void)
> {
> #ifdef CONFIG_SMP
>        smp_send_stop();
> #endif
> }
>
> void machine_restart(char *cmd)
> {
>        machine_shutdown();
>        arm_pm_restart(reboot_mode, cmd);
> }
>
> smp_send_stop() brings the other CPUs down to a quiescent state, waits for
> up to one second for that to happen, and then starts flushing caches etc.
> No other CPU should be active at the point where arm_pm_restart() is
> called.  There should be no other threads active on either this or any
> other CPU.

Thanks, we got it. This was missing in linux-2.6.37 where the code was

 void smp_send_stop(void)
 {
         cpumask_t mask = cpu_online_map;
         cpu_clear(smp_processor_id(), mask);
         if (!cpus_empty(mask))
                 send_ipi_message(&mask, IPI_CPU_STOP);
 }

I would try this change and see if it works for me.

-- 
regards
Shiraz Hashim