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authorCaesar Wang <wxt@rock-chips.com>2015-06-09 12:49:58 +0300
committerHeiko Stuebner <heiko@sntech.de>2015-07-06 01:46:59 +0300
commite306bc16c53199e7440e1fee69dd91dc0a56edee (patch)
treef918e432d41d2b19e4aa2b096aeb900132ca6a4c /arch/arm/mach-rockchip
parentfe4407c0dc58215a7abfb7532740d79ddabe7a7a (diff)
downloadlinux-e306bc16c53199e7440e1fee69dd91dc0a56edee.tar.xz
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>
Diffstat (limited to 'arch/arm/mach-rockchip')
-rw-r--r--arch/arm/mach-rockchip/platsmp.c7
1 files changed, 7 insertions, 0 deletions
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;
}