From e306bc16c53199e7440e1fee69dd91dc0a56edee Mon Sep 17 00:00:00 2001 From: Caesar Wang Date: Tue, 9 Jun 2015 17:49:58 +0800 Subject: [PATCH] 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 Reviewed-by: Douglas Anderson Reviewed-by: Kever Yang Signed-off-by: Heiko Stuebner --- arch/arm/mach-rockchip/platsmp.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/arch/arm/mach-rockchip/platsmp.c b/arch/arm/mach-rockchip/platsmp.c index d1a5fec68887..4187ac2b01b3 100644 --- a/arch/arm/mach-rockchip/platsmp.c +++ b/arch/arm/mach-rockchip/platsmp.c @@ -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; } -- 2.20.1