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Date: Tue, 2 Jan 2024 11:41:38 -0700
From: Mathieu Poirier <mathieu.poirier@linaro.org>
To: Ulf Hansson <ulf.hansson@linaro.org>
Cc: "Rafael J . Wysocki" <rafael@kernel.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Viresh Kumar <viresh.kumar@linaro.org>, linux-pm@vger.kernel.org,
	Sudeep Holla <sudeep.holla@arm.com>,
	Kevin Hilman <khilman@kernel.org>,
	Konrad Dybcio <konrad.dybcio@linaro.org>,
	Bjorn Andersson <andersson@kernel.org>,
	Nikunj Kela <nkela@quicinc.com>,
	Prasad Sodagudi <psodagud@quicinc.com>,
	Stephan Gerhold <stephan@gerhold.net>,
	Ben Horgan <Ben.Horgan@arm.com>, linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	linux-remoteproc@vger.kernel.org, linux-media@vger.kernel.org,
	Shawn Guo <shawnguo@kernel.org>,
	Sascha Hauer <s.hauer@pengutronix.de>
Subject: Re: [PATCH 3/5] remoteproc: imx_rproc: Convert to
 dev_pm_domain_attach|detach_list()
Message-ID: <ZZRY4rMjjkIsG3Ef@p14s>
References: <20231228114157.104822-1-ulf.hansson@linaro.org>
 <20231228114157.104822-4-ulf.hansson@linaro.org>
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In-Reply-To: <20231228114157.104822-4-ulf.hansson@linaro.org>

Hi Ulf,

I'm in agreement with the modifications done to imx_rproc.c and imx_dsp_rproc.c.
There is one thing I am ambivalent on, please see below.

On Thu, Dec 28, 2023 at 12:41:55PM +0100, Ulf Hansson wrote:
> Let's avoid the boilerplate code to manage the multiple PM domain case, by
> converting into using dev_pm_domain_attach|detach_list().
> 
> Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
> Cc: Bjorn Andersson <andersson@kernel.org>
> Cc: Shawn Guo <shawnguo@kernel.org>
> Cc: Sascha Hauer <s.hauer@pengutronix.de>
> Cc: <linux-remoteproc@vger.kernel.org>
> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
> ---
>  drivers/remoteproc/imx_rproc.c | 73 +++++-----------------------------
>  1 file changed, 9 insertions(+), 64 deletions(-)
> 
> diff --git a/drivers/remoteproc/imx_rproc.c b/drivers/remoteproc/imx_rproc.c
> index 8bb293b9f327..3161f14442bc 100644
> --- a/drivers/remoteproc/imx_rproc.c
> +++ b/drivers/remoteproc/imx_rproc.c
> @@ -92,7 +92,6 @@ struct imx_rproc_mem {
>  
>  static int imx_rproc_xtr_mbox_init(struct rproc *rproc);
>  static void imx_rproc_free_mbox(struct rproc *rproc);
> -static int imx_rproc_detach_pd(struct rproc *rproc);
>  
>  struct imx_rproc {
>  	struct device			*dev;
> @@ -113,10 +112,8 @@ struct imx_rproc {
>  	u32				rproc_pt;	/* partition id */
>  	u32				rsrc_id;	/* resource id */
>  	u32				entry;		/* cpu start address */
> -	int                             num_pd;
>  	u32				core_index;
> -	struct device                   **pd_dev;
> -	struct device_link              **pd_dev_link;
> +	struct dev_pm_domain_list	*pd_list;
>  };
>  
>  static const struct imx_rproc_att imx_rproc_att_imx93[] = {
> @@ -853,7 +850,7 @@ static void imx_rproc_put_scu(struct rproc *rproc)
>  		return;
>  
>  	if (imx_sc_rm_is_resource_owned(priv->ipc_handle, priv->rsrc_id)) {
> -		imx_rproc_detach_pd(rproc);
> +		dev_pm_domain_detach_list(priv->pd_list);
>  		return;
>  	}
>  
> @@ -880,72 +877,20 @@ static int imx_rproc_partition_notify(struct notifier_block *nb,
>  static int imx_rproc_attach_pd(struct imx_rproc *priv)
>  {
>  	struct device *dev = priv->dev;
> -	int ret, i;
> -
> -	/*
> -	 * If there is only one power-domain entry, the platform driver framework
> -	 * will handle it, no need handle it in this driver.
> -	 */
> -	priv->num_pd = of_count_phandle_with_args(dev->of_node, "power-domains",
> -						  "#power-domain-cells");
> -	if (priv->num_pd <= 1)
> -		return 0;

In function dev_pm_domain_attach_list(), this condition is "<= 0" rather than
"<= 1".  As such the association between the device and power domain will be
done twice when there is a single power domain, i.e once by the core and once in
dev_pm_domain_attach_list().

I am assuming the runtime PM subsystem is smart enough to deal with this kind of
situation but would like a confirmation.

Thanks,
Mathieu

> -
> -	priv->pd_dev = devm_kmalloc_array(dev, priv->num_pd, sizeof(*priv->pd_dev), GFP_KERNEL);
> -	if (!priv->pd_dev)
> -		return -ENOMEM;
> -
> -	priv->pd_dev_link = devm_kmalloc_array(dev, priv->num_pd, sizeof(*priv->pd_dev_link),
> -					       GFP_KERNEL);
> -
> -	if (!priv->pd_dev_link)
> -		return -ENOMEM;
> -
> -	for (i = 0; i < priv->num_pd; i++) {
> -		priv->pd_dev[i] = dev_pm_domain_attach_by_id(dev, i);
> -		if (IS_ERR(priv->pd_dev[i])) {
> -			ret = PTR_ERR(priv->pd_dev[i]);
> -			goto detach_pd;
> -		}
> -
> -		priv->pd_dev_link[i] = device_link_add(dev, priv->pd_dev[i], DL_FLAG_STATELESS |
> -						       DL_FLAG_PM_RUNTIME | DL_FLAG_RPM_ACTIVE);
> -		if (!priv->pd_dev_link[i]) {
> -			dev_pm_domain_detach(priv->pd_dev[i], false);
> -			ret = -EINVAL;
> -			goto detach_pd;
> -		}
> -	}
> -
> -	return 0;
> -
> -detach_pd:
> -	while (--i >= 0) {
> -		device_link_del(priv->pd_dev_link[i]);
> -		dev_pm_domain_detach(priv->pd_dev[i], false);
> -	}
> -
> -	return ret;
> -}
> -
> -static int imx_rproc_detach_pd(struct rproc *rproc)
> -{
> -	struct imx_rproc *priv = rproc->priv;
> -	int i;
> +	int ret;
> +	struct dev_pm_domain_attach_data pd_data = {
> +		.pd_flags = PD_FLAG_DEV_LINK_ON,
> +	};
>  
>  	/*
>  	 * If there is only one power-domain entry, the platform driver framework
>  	 * will handle it, no need handle it in this driver.
>  	 */
> -	if (priv->num_pd <= 1)
> +	if (dev->pm_domain)
>  		return 0;
>  
> -	for (i = 0; i < priv->num_pd; i++) {
> -		device_link_del(priv->pd_dev_link[i]);
> -		dev_pm_domain_detach(priv->pd_dev[i], false);
> -	}
> -
> -	return 0;
> +	ret = dev_pm_domain_attach_list(dev, &pd_data, &priv->pd_list);
> +	return ret < 0 ? ret : 0;
>  }
>  
>  static int imx_rproc_detect_mode(struct imx_rproc *priv)
> -- 
> 2.34.1
>