linux-kernel - Re: [PATCH 3/5] remoteproc: imx_rproc: Convert to dev_pm_domain_attach|detach

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Message-ID: <CANLsYkzAG4EdYgQ9hNgMB3icGY_yrNwXesBnYxnBtzakrGv7zg@mail.gmail.com>
Date: Wed, 3 Jan 2024 09:19:08 -0700
From: Mathieu Poirier <mathieu.poirier@...aro.org>
To: Ulf Hansson <ulf.hansson@...aro.org>
Cc: "Rafael J . Wysocki" <rafael@...nel.org>, Greg Kroah-Hartman <gregkh@...uxfoundation.org>, 
	Viresh Kumar <viresh.kumar@...aro.org>, linux-pm@...r.kernel.org, 
	Sudeep Holla <sudeep.holla@....com>, Kevin Hilman <khilman@...nel.org>, 
	Konrad Dybcio <konrad.dybcio@...aro.org>, Bjorn Andersson <andersson@...nel.org>, 
	Nikunj Kela <nkela@...cinc.com>, Prasad Sodagudi <psodagud@...cinc.com>, 
	Stephan Gerhold <stephan@...hold.net>, Ben Horgan <Ben.Horgan@....com>, linux-kernel@...r.kernel.org, 
	linux-arm-kernel@...ts.infradead.org, linux-remoteproc@...r.kernel.org, 
	linux-media@...r.kernel.org, Shawn Guo <shawnguo@...nel.org>, 
	Sascha Hauer <s.hauer@...gutronix.de>
Subject: Re: [PATCH 3/5] remoteproc: imx_rproc: Convert to dev_pm_domain_attach|detach_list()

On Wed, 3 Jan 2024 at 03:11, Ulf Hansson <ulf.hansson@...aro.org> wrote:
>
> On Tue, 2 Jan 2024 at 19:41, Mathieu Poirier <mathieu.poirier@...aro.org> wrote:
> >
> > 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@...aro.org>
> > > Cc: Bjorn Andersson <andersson@...nel.org>
> > > Cc: Shawn Guo <shawnguo@...nel.org>
> > > Cc: Sascha Hauer <s.hauer@...gutronix.de>
> > > Cc: <linux-remoteproc@...r.kernel.org>
> > > Signed-off-by: Ulf Hansson <ulf.hansson@...aro.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 for reviewing!
>
> To cover the the single PM domain case, imx_rproc_attach_pd() is
> returning 0 when dev->pm_domain has been assigned. Moreover,
> dev_pm_domain_attach_list() doesn't allow attaching in the single PM
> domain case, as it returns -EEXIST if "dev->pm_domain" is already
> assigned.
>
> Did that make sense to you?
>

Ah yes!  The correlation between dev->pm_domain and the magic done by
the core framework was lost on me.

Once you respin to address Nikunj's comment I will ask the NXP team in
Romania to test this set.  With the holiday season still floating in
the air it may take a little while for them to get to it.

> [...]
>
> Kind regards
> Uffe