From mboxrd@z Thu Jan  1 00:00:00 1970
From: Sudeep Holla <sudeep.holla@arm.com>
Subject: Re: [PATCH RFC v1 7/8] drivers: qcom: cpu_pd: Handle cpu hotplug in
 the domain
Date: Fri, 12 Oct 2018 15:25:04 +0100
Message-ID: <20181012142503.GF3401@e107155-lin>
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To: "Raju P.L.S.S.S.N" <rplsssn@codeaurora.org>
Cc: andy.gross@linaro.org, david.brown@linaro.org, rjw@rjwysocki.net, ulf.hansson@linaro.org, khilman@kernel.org, linux-arm-msm@vger.kernel.org, linux-soc@vger.kernel.org, rnayak@codeaurora.org, bjorn.andersson@linaro.org, linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, devicetree@vger.kernel.org, sboyd@kernel.org, evgreen@chromium.org, dianders@chromium.org, mka@chromium.org, ilina@codeaurora.org, Sudeep Holla <sudeep.holla@arm.com>
List-Id: devicetree@vger.kernel.org

On Thu, Oct 11, 2018 at 02:50:54AM +0530, Raju P.L.S.S.S.N wrote:
> Use cpu hotplug callback mechanism to attach/dettach the cpu in
> the cpu power domain. During cpu hotplug callback registration,
> the starting callback is invoked on all online cpus. So there is
> no need to attach from device probe.
> 
> Signed-off-by: Raju P.L.S.S.S.N <rplsssn@codeaurora.org>
> ---
>  drivers/soc/qcom/cpu_pd.c  | 33 +++++++++++++++++++++++++--------
>  include/linux/cpuhotplug.h |  1 +
>  2 files changed, 26 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/soc/qcom/cpu_pd.c b/drivers/soc/qcom/cpu_pd.c
> index 242eced..bf2d95d 100644
> --- a/drivers/soc/qcom/cpu_pd.c
> +++ b/drivers/soc/qcom/cpu_pd.c
> @@ -3,6 +3,7 @@
>   * Copyright (c) 2018, The Linux Foundation. All rights reserved.
>   */
>  
> +#include <linux/cpuhotplug.h>
>  #include <linux/ktime.h>
>  #include <linux/of_platform.h>
>  #include <linux/pm_domain.h>
> @@ -85,12 +86,26 @@ static int cpu_pd_power_off(struct generic_pm_domain *domain)
>  	return 0;
>  }
>  
> +static int cpu_pd_starting(unsigned int cpu)
> +{
> +	if (!suspend && of_genpd_attach_cpu(cpu))
> +		pr_err("%s: genpd_attach_cpu fail\n", __func__);

If it's that serious, return proper error code and drop the message which
could be annoying if you are running some hotplug test loop.

--
Regards,
Sudeep