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[PARISC] Add new function to start local Interval Timer, start_cpu_itimer() 

I couldn't find where the itimer was getting started for slave CPUs.
CPU 0 (master) itimer was started in time_init() (arch/parisc/kernel/time.c).
start_cpu_itimer() code was striped from time_init().
Slaves now start their itimer in smp_cpu_init().

This is a first step towards making gettimeoffset() work for SMP.
Next step will be to determine the CR16 (cycle counter)
offsets for each CPU relative to the master (CPU 0).

Signed-off-by: Grant Grundler <grundler@parisc-linux.org>
Signed-off-by: Kyle McMartin <kyle@parisc-linux.org>
This commit is contained in:
Grant Grundler 2006-09-03 00:02:16 -07:00 committed by Matthew Wilcox
parent 7908a0c72e
commit 56f335c89e
2 changed files with 14 additions and 10 deletions
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4
arch/parisc/kernel/smp.c
View File

@ -430,8 +430,9 @@ smp_do_timer(struct pt_regs *regs)
static void __init
smp_cpu_init(int cpunum)
{
extern int init_per_cpu(int); /* arch/parisc/kernel/setup.c */
extern int init_per_cpu(int); /* arch/parisc/kernel/processor.c */
extern void init_IRQ(void); /* arch/parisc/kernel/irq.c */
extern void start_cpu_itimer(void); /* arch/parisc/kernel/time.c */
/* Set modes and Enable floating point coprocessor */
(void) init_per_cpu(cpunum);
@ -457,6 +458,7 @@ smp_cpu_init(int cpunum)
enter_lazy_tlb(&init_mm, current);
init_IRQ(); /* make sure no IRQ's are enabled or pending */
start_cpu_itimer();
}

20
arch/parisc/kernel/time.c
View File

@ -223,22 +223,24 @@ unsigned long long sched_clock(void)
}
void __init start_cpu_itimer(void)
{
unsigned int cpu = smp_processor_id();
unsigned long next_tick = mfctl(16) + clocktick;
mtctl(next_tick, 16); /* kick off Interval Timer (CR16) */
cpu_data[cpu].it_value = next_tick;
}
void __init time_init(void)
{
unsigned long next_tick;
static struct pdc_tod tod_data;
clocktick = (100 * PAGE0->mem_10msec) / HZ;
halftick = clocktick / 2;
/* Setup clock interrupt timing */
next_tick = mfctl(16);
next_tick += clocktick;
cpu_data[smp_processor_id()].it_value = next_tick;
/* kick off Itimer (CR16) */
mtctl(next_tick, 16);
start_cpu_itimer(); /* get CPU 0 started */
if(pdc_tod_read(&tod_data) == 0) {
write_seqlock_irq(&xtime_lock);