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References: <20240528-pwrseq-v8-0-d354d52b763c@linaro.org> <20240528-pwrseq-v8-10-d354d52b763c@linaro.org>
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From: Bartosz Golaszewski <brgl@bgdev.pl>
Date: Wed, 5 Jun 2024 09:43:02 +0200
Message-ID: <CAMRc=MfyCJgOCBSh7AY4jEujWXGqZBB7Tnkq0VRrAKKCcJ9hAQ@mail.gmail.com>
Subject: Re: [PATCH v8 10/17] power: sequencing: implement the pwrseq core
To: Ratheesh Kannoth <rkannoth@marvell.com>
Cc: Liam Girdwood <lgirdwood@gmail.com>, Mark Brown <broonie@kernel.org>, 
	Rob Herring <robh@kernel.org>, Krzysztof Kozlowski <krzk+dt@kernel.org>, Conor Dooley <conor+dt@kernel.org>, 
	Marcel Holtmann <marcel@holtmann.org>, Luiz Augusto von Dentz <luiz.dentz@gmail.com>, 
	"David S. Miller" <davem@davemloft.net>, Eric Dumazet <edumazet@google.com>, 
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>, 
	Balakrishna Godavarthi <quic_bgodavar@quicinc.com>, Rocky Liao <quic_rjliao@quicinc.com>, 
	Kalle Valo <kvalo@kernel.org>, Jeff Johnson <jjohnson@kernel.org>, 
	Bjorn Andersson <andersson@kernel.org>, Konrad Dybcio <konrad.dybcio@linaro.org>, 
	Bjorn Helgaas <bhelgaas@google.com>, Srini Kandagatla <srinivas.kandagatla@linaro.org>, 
	Elliot Berman <quic_eberman@quicinc.com>, Caleb Connolly <caleb.connolly@linaro.org>, 
	Neil Armstrong <neil.armstrong@linaro.org>, Dmitry Baryshkov <dmitry.baryshkov@linaro.org>, 
	Alex Elder <elder@kernel.org>, linux-arm-msm@vger.kernel.org, 
	linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, 
	linux-bluetooth@vger.kernel.org, netdev@vger.kernel.org, 
	linux-wireless@vger.kernel.org, ath11k@lists.infradead.org, 
	Jeff Johnson <quic_jjohnson@quicinc.com>, ath12k@lists.infradead.org, 
	linux-pm@vger.kernel.org, linux-pci@vger.kernel.org, 
	Bartosz Golaszewski <bartosz.golaszewski@linaro.org>, kernel@quicinc.com, 
	Amit Pundir <amit.pundir@linaro.org>
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On Wed, Jun 5, 2024 at 8:52=E2=80=AFAM Ratheesh Kannoth <rkannoth@marvell.c=
om> wrote:
>
> On 2024-05-29 at 00:33:18, Bartosz Golaszewski (brgl@bgdev.pl) wrote:
> > From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
> >
> > Implement the power sequencing subsystem allowing devices to share
> > complex powering-up and down procedures. It's split into the consumer
> > and provider parts but does not implement any new DT bindings so that
> > the actual power sequencing is never revealed in the DT representation.
> >
> > Tested-by: Amit Pundir <amit.pundir@linaro.org>
> > Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
> > ---
> > +
> > +static struct pwrseq_unit_dep *pwrseq_unit_dep_new(struct pwrseq_unit =
*unit)
> nit. pwrseq_unit_dep_alloc/create rhymes well with pwrseq_unit_dep_free()=
,

So what?

> > +static void pwrseq_unit_free_deps(struct list_head *list)
> > +{
> > +     struct pwrseq_unit_dep *dep, *next;
> > +
> > +     list_for_each_entry_safe(dep, next, list, list) {
> no need of 'locks' to protect against simutaneous 'add' ?

No, this only happens once during release.

> > +
> > +static int pwrseq_unit_setup_deps(const struct pwrseq_unit_data **data=
,
> > +                               struct list_head *dep_list,
> > +                               struct list_head *unit_list,
> > +                               struct radix_tree_root *processed_units=
)
> > +{
> > +     const struct pwrseq_unit_data *pos;
> > +     struct pwrseq_unit_dep *dep;
> > +     struct pwrseq_unit *unit;
> > +     int i;
> > +
> > +     for (i =3D 0; data[i]; i++) {
> Can we add range for i ? just depending on data[i] to be zero looks to be=
 risky.
>

Why? It's perfectly normal to expect users to end the array with a
NULL pointer. The docs say these arrays must be NULL-terminated.

> > +             pos =3D data[i];
> > +
> > +             unit =3D pwrseq_unit_setup(pos, unit_list, processed_unit=
s);
> > +             if (IS_ERR(unit))
> > +                     return PTR_ERR(unit);
> > +
> > +             dep =3D pwrseq_unit_dep_new(unit);
> > +             if (!dep) {
> > +                     pwrseq_unit_decref(unit);
> This frees only one 'unit'. is there any chance for multiple 'unit', then=
 better clean
> up here ?

The references to those will be dropped in pwrseq_release().

> > +
> > +     /*
> > +      * From this point onwards the device's release() callback is
> > +      * responsible for freeing resources.
> > +      */
> > +     device_initialize(&pwrseq->dev);
> > +
> > +     ret =3D dev_set_name(&pwrseq->dev, "pwrseq.%d", pwrseq->id);
> > +     if (ret)
> > +             goto err_put_pwrseq;
> > +
> > +     pwrseq->owner =3D config->owner ?: THIS_MODULE;
> > +     pwrseq->match =3D config->match;
> > +
> > +     init_rwsem(&pwrseq->rw_lock);
> > +     mutex_init(&pwrseq->state_lock);
> > +     INIT_LIST_HEAD(&pwrseq->targets);
> > +     INIT_LIST_HEAD(&pwrseq->units);
> > +
> > +     ret =3D pwrseq_setup_targets(config->targets, pwrseq);
> > +     if (ret)
> > +             goto err_put_pwrseq;
> > +
> > +     scoped_guard(rwsem_write, &pwrseq_sem) {
> > +             ret =3D device_add(&pwrseq->dev);
> > +             if (ret)
> > +                     goto err_put_pwrseq;
> > +     }
> > +
> > +     return pwrseq;
> > +
> > +err_put_pwrseq:
> no need to kfree(pwrseq) ?

It's literally put on the next line?

Bart