| Message ID | 1433747496-7642-3-git-send-email-wxt@rock-chips.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Mon, Jun 08, 2015 at 03:11:35PM +0800, Caesar Wang wrote: > diff --git a/arch/arm/mach-rockchip/platsmp.c b/arch/arm/mach-rockchip/platsmp.c > index bd40852..5bc2a89 100644 > --- a/arch/arm/mach-rockchip/platsmp.c > +++ b/arch/arm/mach-rockchip/platsmp.c > @@ -321,6 +321,9 @@ static void __init rockchip_smp_prepare_cpus(unsigned int max_cpus) > #ifdef CONFIG_HOTPLUG_CPU > static int rockchip_cpu_kill(unsigned int cpu) > { > + /* ensure CPU can enter the WFI/WFE state */ I would like to see a better comment here, describing what the problem is. Maybe something like this: /* * 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. */ Thanks. > + mdelay(1); > + > pmu_set_power_domain(0 + cpu, false); > return 1; > } > -- > 1.9.1 >
? 2015?06?08? 17:28, Russell King - ARM Linux ??: > On Mon, Jun 08, 2015 at 03:11:35PM +0800, Caesar Wang wrote: >> diff --git a/arch/arm/mach-rockchip/platsmp.c b/arch/arm/mach-rockchip/platsmp.c >> index bd40852..5bc2a89 100644 >> --- a/arch/arm/mach-rockchip/platsmp.c >> +++ b/arch/arm/mach-rockchip/platsmp.c >> @@ -321,6 +321,9 @@ static void __init rockchip_smp_prepare_cpus(unsigned int max_cpus) >> #ifdef CONFIG_HOTPLUG_CPU >> static int rockchip_cpu_kill(unsigned int cpu) >> { >> + /* ensure CPU can enter the WFI/WFE state */ > I would like to see a better comment here, describing what the problem > is. Maybe something like this: > > /* > * 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. > */ > > Thanks. OK, Thanks! >> + mdelay(1); >> + >> pmu_set_power_domain(0 + cpu, false); >> return 1; >> } >> -- >> 1.9.1 >>
diff --git a/arch/arm/mach-rockchip/platsmp.c b/arch/arm/mach-rockchip/platsmp.c index bd40852..5bc2a89 100644 --- a/arch/arm/mach-rockchip/platsmp.c +++ b/arch/arm/mach-rockchip/platsmp.c @@ -321,6 +321,9 @@ static void __init rockchip_smp_prepare_cpus(unsigned int max_cpus) #ifdef CONFIG_HOTPLUG_CPU static int rockchip_cpu_kill(unsigned int cpu) { + /* ensure CPU can enter the WFI/WFE state */ + mdelay(1); + pmu_set_power_domain(0 + cpu, false); return 1; }
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> Changes in v5: - Fix the patch decription. - Add the changelog. Changes in v4: None Changes in v3: None Changes in v2: None Changes in v2: - As Kever points out, Fix the subject typo WFI/WFE. --- arch/arm/mach-rockchip/platsmp.c | 3 +++ 1 file changed, 3 insertions(+)