Messages in this thread | | | Subject | Re: [PATCH] ARM: bcm2836: Send event when onlining other cores | From | Florian Fainelli <> | Date | Mon, 14 Aug 2017 09:25:16 -0700 |
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On 08/08/2017 04:04 AM, Phil Elwell wrote: > Secondary cores should enter a low-power idle state when waiting to > be started. The "wfe" instruction causes a core to wait until an event > or interrupt arrives before continuing to the next instruction, and > the "sev" instruction sends a wakeup event to the other cores. > > Add an "sev" (and a memory barrier) to bcm2836_boot_secondary, the > function that wakes the waiting cores during booting. This is required > if the secondary cores are sitting in "wfe", and harmless if not.
Eric, should I just pick this up for the upcoming ARM SoC pull requests that I am preparing, or do you have more changes aside from the two tags I already merged?
Thanks!
> > Signed-off-by: Phil Elwell <phil@raspberrypi.org> > --- > arch/arm/mach-bcm/platsmp.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/arch/arm/mach-bcm/platsmp.c b/arch/arm/mach-bcm/platsmp.c > index 3fa1a99..7811160 100644 > --- a/arch/arm/mach-bcm/platsmp.c > +++ b/arch/arm/mach-bcm/platsmp.c > @@ -312,6 +312,9 @@ static int bcm2836_boot_secondary(unsigned int cpu, struct task_struct *idle) > writel(virt_to_phys(secondary_startup), > intc_base + LOCAL_MAILBOX3_SET0 + 16 * cpu); > > + dsb(sy); > + sev(); > + > iounmap(intc_base); > > return 0; >
-- Florian
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