Messages in this thread Patch in this message | | | From | Phil Elwell <> | Subject | [PATCH] ARM: bcm2836: Send event when onlining other cores | Date | Tue, 8 Aug 2017 12:04:55 +0100 |
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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.
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; -- 1.9.1
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