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References: <20230802150018.327079-1-apatel@ventanamicro.com>
 <20230802150018.327079-3-apatel@ventanamicro.com> <20230811193924.GA3997669-robh@kernel.org>
In-Reply-To: <20230811193924.GA3997669-robh@kernel.org>
From:   Anup Patel <apatel@ventanamicro.com>
Date:   Sat, 12 Aug 2023 08:19:30 +0530
Message-ID: <CAK9=C2Wncgu2U_EqP0xKNQ7aau947zhE+-hy5pguV=LP=ANikA@mail.gmail.com>
Subject: Re: [PATCH v7 02/15] of: property: Add fw_devlink support for msi-parent
To:     Rob Herring <robh@kernel.org>
Cc:     Palmer Dabbelt <palmer@dabbelt.com>,
        Paul Walmsley <paul.walmsley@sifive.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Marc Zyngier <maz@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Frank Rowand <frowand.list@gmail.com>,
        Conor Dooley <conor+dt@kernel.org>,
        Atish Patra <atishp@atishpatra.org>,
        Andrew Jones <ajones@ventanamicro.com>,
        Sunil V L <sunilvl@ventanamicro.com>,
        Saravana Kannan <saravanak@google.com>,
        Anup Patel <anup@brainfault.org>,
        linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
        devicetree@vger.kernel.org
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On Sat, Aug 12, 2023 at 1:09=E2=80=AFAM Rob Herring <robh@kernel.org> wrote=
:
>
> On Wed, Aug 02, 2023 at 08:30:05PM +0530, Anup Patel wrote:
> > This allows fw_devlink to create device links between consumers of
> > a MSI and the supplier of the MSI.
> >
> > Signed-off-by: Anup Patel <apatel@ventanamicro.com>
> > ---
> >  drivers/of/property.c | 32 ++++++++++++++++++++++++++++++++
> >  1 file changed, 32 insertions(+)
> >
> > diff --git a/drivers/of/property.c b/drivers/of/property.c
> > index ddc75cd50825..bc20535deed7 100644
> > --- a/drivers/of/property.c
> > +++ b/drivers/of/property.c
> > @@ -1325,6 +1325,37 @@ static struct device_node *parse_interrupts(stru=
ct device_node *np,
> >       return of_irq_parse_one(np, index, &sup_args) ? NULL : sup_args.n=
p;
> >  }
> >
> > +static struct device_node *parse_msi_parent(struct device_node *np,
> > +                                         const char *prop_name, int in=
dex)
> > +{
> > +     struct of_phandle_args sup_args;
> > +     struct device_node *msi_np;
> > +
> > +     if (IS_ENABLED(CONFIG_SPARC))
> > +             return NULL;
> > +
> > +     if (strcmp(prop_name, "msi-parent"))
> > +             return NULL;
> > +
> > +     msi_np =3D of_parse_phandle(np, prop_name, 0);
> > +     if (msi_np) {
> > +             if (!of_property_read_bool(msi_np, "#msi-cells")) {
>
> Use of_property_present() to check presence.
>
> However, this check is wrong. #msi-cells is optional and assumed to be 0
> if not present. There's another flavor of of_parse_phandle_with_args()
> that allows specifying a default cell count, so I think you can get rid
> of all this checking.

Okay, I will update in the next revision.

Thanks,
Anup

>
> > +                     if (index) {
> > +                             of_node_put(msi_np);
> > +                             return NULL;
> > +                     }
> > +                     return msi_np;
> > +             }
> > +             of_node_put(msi_np);
> > +     }
> > +
> > +     if (of_parse_phandle_with_args(np, prop_name, "#msi-cells", index=
,
> > +                                    &sup_args))
> > +             return NULL;
> > +
> > +     return sup_args.np;
> > +}
> > +
> >  static const struct supplier_bindings of_supplier_bindings[] =3D {
> >       { .parse_prop =3D parse_clocks, },
> >       { .parse_prop =3D parse_interconnects, },
> > @@ -1359,6 +1390,7 @@ static const struct supplier_bindings of_supplier=
_bindings[] =3D {
> >       { .parse_prop =3D parse_regulators, },
> >       { .parse_prop =3D parse_gpio, },
> >       { .parse_prop =3D parse_gpios, },
> > +     { .parse_prop =3D parse_msi_parent, },
> >       {}
> >  };
> >
> > --
> > 2.34.1
> >