[U-Boot] [PATCH 04/28] armv8/ls2085a: Fix generic timer clock source

Mark Rutland
2015-03-19T18:17:52Z

On Thu, Mar 19, 2015 at 06:16:25PM +0000, York Sun wrote:
> On 03/19/2015 11:08 AM, Mark Rutland wrote:
> >> +
> >> +int timer_init(void)
> >> +{
> >> + u32 __iomem *cntcr = (u32 *)CONFIG_SYS_FSL_TIMER_ADDR;
> >> + u32 __iomem *cltbenr = (u32 *)CONFIG_SYS_FSL_PMU_CLTBENR;
> >> +#ifdef COUNTER_FREQUENCY_REAL
> >> + unsigned long cntfrq = COUNTER_FREQUENCY_REAL;
> >> +
> >> + /* Update with accurate clock frequency */
> >> + asm volatile("msr cntfrq_el0, %0" : : "r" (cntfrq) : "memory");
> >> +#endif
> >
> > Is this executed on all CPUs, or do secondary CPUs have CNTFRQ
> > programmed with the correct value elsewhere?
> >
>
> Only the primary CPU runs here. The secondary CPU doesn't come here.

Ok. Where does CNTFRQ get programmed for those CPUs?

If it's necessary to write COUNTER_FREQUENCY_REAL to the primary CPU's
CNTFRQ, that's also necessary on the secondaries before they enter the
OS.

Mark.