On Thu, Oct 10, 2019 at 01:39:36PM +0200, Ulf Hansson wrote:
> In case we have succeeded to attach a CPU to its PM domain, let's deploy
> runtime PM support for the corresponding attached device, to allow the CPU
> to be powered-managed accordingly.
>
> To set the triggering point for when runtime PM reference counting should
> be done, let's store the index of deepest idle state for the CPU in the per
> CPU struct. Then use this index to compare the selected idle state index
> when entering idle, as to understand whether runtime PM reference counting
> is needed or not.
>
> Note that, from the hierarchical point view, there may be good reasons to
> do runtime PM reference counting even on shallower idle states, but at this
> point this isn't supported, mainly due to limitations set by the generic PM
> domain.
>
> Signed-off-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
> ---
> drivers/cpuidle/cpuidle-psci.c | 21 +++++++++++++++++++--
> 1 file changed, 19 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/cpuidle/cpuidle-psci.c b/drivers/cpuidle/cpuidle-psci.c
> index 1510422c7a53..0919b40c1a85 100644
> --- a/drivers/cpuidle/cpuidle-psci.c
> +++ b/drivers/cpuidle/cpuidle-psci.c
> @@ -16,6 +16,7 @@
> #include <linux/of.h>
> #include <linux/of_device.h>
> #include <linux/psci.h>
> +#include <linux/pm_runtime.h>
> #include <linux/slab.h>
>
> #include <asm/cpuidle.h>
> @@ -25,6 +26,7 @@
>
> struct psci_cpuidle_data {
> u32 *psci_states;
> + u32 rpm_state_id;
> struct device *dev;
> };
>
> @@ -50,14 +52,28 @@ static int psci_enter_idle_state(struct cpuidle_device *dev,
> struct cpuidle_driver *drv, int idx)
> {
> int ret;
> - u32 *states = __this_cpu_read(psci_cpuidle_data.psci_states);
> - u32 state = psci_get_domain_state();
> + struct psci_cpuidle_data *data = this_cpu_ptr(&psci_cpuidle_data);
> + u32 *states = data->psci_states;
> + struct device *pd_dev = data->dev;
> + bool runtime_pm = (pd_dev && data->rpm_state_id == idx);
> + u32 state;
Wonder if we can have separate psci_enter_idle_state for OSI mode so
that all these runtime extra check can be reduced ? It will also make
sure there's no additional latency for PC mode because of OSI.
--
Regards,
Sudeep
