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From:   Chunyan Zhang <zhang.lyra@gmail.com>
Date:   Mon, 20 Apr 2020 17:36:01 +0800
Message-ID: <CABOV4+XaTMd=A5_5eTtGG=S3DvgBCTxrqV4aXnp55pTsdbO4NA@mail.gmail.com>
Subject: Re: [RFC PATCH v1 1/2] cpuidle: allow idle state to be found as
 deepest state for s2idle only
To:     "Rafael J . Wysocki" <rjw@rjwysocki.net>,
        Daniel Lezcano <daniel.lezcano@linaro.org>,
        Rob Herring <robh+dt@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>
Cc:     linux-pm@vger.kernel.org, devicetree@vger.kernel.org,
        LKML <linux-kernel@vger.kernel.org>,
        Chunyan Zhang <chunyan.zhang@unisoc.com>
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Hello,

Any comments or suggests on this? That would be very appreciated.

Thanks,
Chunyan


On Mon, Apr 13, 2020 at 5:09 PM <zhang.lyra@gmail.com> wrote:
>
> From: Chunyan Zhang <chunyan.zhang@unisoc.com>
>
> Add a new flag CPUIDLE_FLAG_S2IDLE to allow c-state to be found as
> deepest state for s2idle only, so that users can add a new c-state
> for using s2idle and don't worry disturbing other use cases such as
> play_idle() which probably don't want to enter into so much deep
> idle state since devices are not suspended for that kind of cases.
>
> Signed-off-by: Chunyan Zhang <chunyan.zhang@unisoc.com>
> ---
>  drivers/cpuidle/cpuidle.c        | 3 ++-
>  drivers/cpuidle/dt_idle_states.c | 3 +++
>  include/linux/cpuidle.h          | 1 +
>  3 files changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
> index de81298051b3..bb61f0c271d2 100644
> --- a/drivers/cpuidle/cpuidle.c
> +++ b/drivers/cpuidle/cpuidle.c
> @@ -89,7 +89,8 @@ static int find_deepest_state(struct cpuidle_driver *drv,
>                     s->exit_latency_ns <= latency_req ||
>                     s->exit_latency_ns > max_latency_ns ||
>                     (s->flags & forbidden_flags) ||
> -                   (s2idle && !s->enter_s2idle))
> +                   (s2idle && !s->enter_s2idle) ||
> +                   (!s2idle && (s->flags & CPUIDLE_FLAG_S2ILDE)))
>                         continue;
>
>                 latency_req = s->exit_latency_ns;
> diff --git a/drivers/cpuidle/dt_idle_states.c b/drivers/cpuidle/dt_idle_states.c
> index 252f2a9686a6..530db2726c05 100644
> --- a/drivers/cpuidle/dt_idle_states.c
> +++ b/drivers/cpuidle/dt_idle_states.c
> @@ -80,6 +80,9 @@ static int init_state_node(struct cpuidle_state *idle_state,
>         idle_state->flags = 0;
>         if (of_property_read_bool(state_node, "local-timer-stop"))
>                 idle_state->flags |= CPUIDLE_FLAG_TIMER_STOP;
> +
> +       if (of_property_read_bool(state_node, "for-s2idle-only"))
> +               idle_state->flags |= CPUIDLE_FLAG_S2ILDE;
>         /*
>          * TODO:
>          *      replace with kstrdup and pointer assignment when name
> diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h
> index ec2ef63771f0..08da701f74cd 100644
> --- a/include/linux/cpuidle.h
> +++ b/include/linux/cpuidle.h
> @@ -78,6 +78,7 @@ struct cpuidle_state {
>  #define CPUIDLE_FLAG_TIMER_STOP BIT(2) /* timer is stopped on this state */
>  #define CPUIDLE_FLAG_UNUSABLE  BIT(3) /* avoid using this state */
>  #define CPUIDLE_FLAG_OFF       BIT(4) /* disable this state by default */
> +#define CPUIDLE_FLAG_S2ILDE    BIT(5) /* state is used for s2idle only */
>
>  struct cpuidle_device_kobj;
>  struct cpuidle_state_kobj;
> --
> 2.20.1
>