Re: [PATCH v6 02/14] of: property: Add fw_devlink support for msi-parent

[Anup Patel]

On Thu, Jul 20, 2023 at 4:08 AM Rob Herring <robh@xxxxxxxxxx> wrote:
>
> On Wed, Jul 19, 2023 at 05:05:30PM +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@xxxxxxxxxxxxxxxx>
> > ---
> >  drivers/of/property.c | 32 ++++++++++++++++++++++++++++++++
> >  1 file changed, 32 insertions(+)
> >
> > diff --git a/drivers/of/property.c b/drivers/of/property.c
> > index ddc75cd50825..e4096b79a872 100644
> > --- a/drivers/of/property.c
> > +++ b/drivers/of/property.c
> > @@ -1325,6 +1325,37 @@ static struct device_node *parse_interrupts(struct device_node *np,
> >       return of_irq_parse_one(np, index, &sup_args) ? NULL : sup_args.np;
> >  }
> >
> > +static struct device_node *parse_msi_parent(struct device_node *np,
> > +                                         const char *prop_name, int index)
> > +{
> > +     struct of_phandle_args sup_args;
> > +     struct device_node *msi_np;
> > +
> > +     if (!IS_ENABLED(CONFIG_OF_IRQ))
> > +             return NULL;
>
> Why do we need this? Sparc is not going to have MSI properties to begin
> with. I guess it saves a little bit of code. Though Sparc doesn't need
> any of this file. Or maybe there's a better kconfig symbol to use here
> if MSIs are not supported?

I can't think of a better kconfig symbol over here but since Sparc does
not have MSI properties, I think following is better:

if (IS_ENABLED(CONFIG_SPARC))
    return NULL;

Any other suggestions ?

Regards,
Anup

>
> > +
> > +     if (strcmp(prop_name, "msi-parent"))
> > +             return NULL;
> > +
> > +     msi_np = of_parse_phandle(np, prop_name, 0);
> > +     if (msi_np) {
> > +             if (!of_property_read_bool(msi_np, "#msi-cells")) {
> > +                     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[] = {
> >       { .parse_prop = parse_clocks, },
> >       { .parse_prop = parse_interconnects, },
> > @@ -1359,6 +1390,7 @@ static const struct supplier_bindings of_supplier_bindings[] = {
> >       { .parse_prop = parse_regulators, },
> >       { .parse_prop = parse_gpio, },
> >       { .parse_prop = parse_gpios, },
> > +     { .parse_prop = parse_msi_parent, },
> >       {}
> >  };
> >
> > --
> > 2.34.1
> >