/*
Try exclusive cpu run func, the others wait it for finishing.
If try fail, you can try again.
NOTE: It need call at non-automatic context, because of mutex_lock @ cpu_maps_update_begin*/
int try_exclu_cpu_exe(exl_call_func_t func, void * p_arg)
{
unsigned int cpu;
unsigned long irq_flags;
unsigned long jiffy_timeout;
unsigned long count=0;
int ret;
/*Protect hotplug scenary*/
cpu_maps_update_begin();
timeout_flag = 0; // clean timeout flag;
for(cpu=0; cpu< CONFIG_NR_CPUS; cpu++)
if(per_cpu(in_wait, cpu))
{
printk("The previous call is not complete yet!\n");
ret = -1;
goto finish2;
}
smp_call_function(/*(void (*) (void * info))*/smp_wait, NULL, 0);
irq_flags = arch_local_irq_save();
jiffy_timeout = jiffies + HZ/2; //0.5s
while(count+1 != num_online_cpus())//the other cpus all in wait loop when count+1 == num_online_cpus()
{
if(time_after(jiffies, jiffy_timeout))
{
printk("Cannot stall other cpus. Timeout!\n");
timeout_flag = 1;
ret = -1;
goto finish1;
}
for(cpu=0, count=0; cpu< CONFIG_NR_CPUS; cpu++)
if(per_cpu(in_wait, cpu) == SMP_FLAG_GETED)
count ++;
}
ret = func(p_arg);
finish1:
for(cpu=0; cpu< CONFIG_NR_CPUS; cpu++)
per_cpu(in_wait, cpu) = SMP_FLAG_IDLE;
arch_local_irq_restore(irq_flags);
finish2:
cpu_maps_update_done();
return ret;
}
static cycle_t arc_counter_read(struct clocksource *cs)
{
unsigned long flags;
union {
#ifdef CONFIG_CPU_BIG_ENDIAN
struct { u32 high, low; };
#else
struct { u32 low, high; };
#endif
cycle_t full;
} stamp;
flags = arch_local_irq_save();
__asm__ __volatile(
" .extCoreRegister tsch, 58, r, cannot_shortcut \n"
" rtsc %0, 0 \n"
" mov %1, 0 \n"
: "=r" (stamp.low), "=r" (stamp.high));
arch_local_irq_restore(flags);
return stamp.full;
}
