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ARM: rockchip: ensure CPU to enter WFI/WFE state 

The patch can ensure that v7_exit_coherency_flush() in rockchip_cpu_die()
executed in time.
The mdelay(1) has enough time to fix the problem of CPU offlining.
That's a workaround way in rockchip hotplug code,
At least, we haven't a better way to solve it. Who know,
that maybe fixed by chip (hardware) in the future.

Signed-off-by: Caesar Wang <wxt@rock-chips.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
This commit is contained in:
Caesar Wang 2015-06-09 17:49:58 +08:00 committed by Heiko Stuebner
parent fe4407c0dc
commit e306bc16c5
1 changed files with 7 additions and 0 deletions
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7
arch/arm/mach-rockchip/platsmp.c
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@ -321,6 +321,13 @@ static void __init rockchip_smp_prepare_cpus(unsigned int max_cpus)
#ifdef CONFIG_HOTPLUG_CPU
static int rockchip_cpu_kill(unsigned int cpu)
{
/*
* We need a delay here to ensure that the dying CPU can finish
* executing v7_coherency_exit() and reach the WFI/WFE state
* prior to having the power domain disabled.
*/
mdelay(1);
pmu_set_power_domain(0 + cpu, false);
return 1;
}