Re: [PATCH 10/12] of/irq: Make of_msi_map_rid() PCI bus agnostic

[Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>]

On Thu, May 21, 2020 at 05:17:27PM -0600, Rob Herring wrote:
> On Thu, May 21, 2020 at 7:00 AM Lorenzo Pieralisi
> <lorenzo.pieralisi@arm.com> wrote:
> >
> > There is nothing PCI bus specific in the of_msi_map_rid()
> > implementation other than the requester ID tag for the input
> > ID space. Rename requester ID to a more generic ID so that
> > the translation code can be used by all busses that require
> > input/output ID translations.
> >
> > Leave a wrapper function of_msi_map_rid() in place to keep
> > existing PCI code mapping requester ID syntactically unchanged.
> >
> > No functional change intended.
> >
> > Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
> > Cc: Rob Herring <robh+dt@kernel.org>
> > Cc: Marc Zyngier <maz@kernel.org>
> > ---
> >  drivers/of/irq.c       | 28 ++++++++++++++--------------
> >  include/linux/of_irq.h | 14 ++++++++++++--
> >  2 files changed, 26 insertions(+), 16 deletions(-)
> >
> > diff --git a/drivers/of/irq.c b/drivers/of/irq.c
> > index 48a40326984f..25d17b8a1a1a 100644
> > --- a/drivers/of/irq.c
> > +++ b/drivers/of/irq.c
> > @@ -576,43 +576,43 @@ void __init of_irq_init(const struct of_device_id *matches)
> >         }
> >  }
> >
> > -static u32 __of_msi_map_rid(struct device *dev, struct device_node **np,
> > -                           u32 rid_in)
> > +static u32 __of_msi_map_id(struct device *dev, struct device_node **np,
> > +                           u32 id_in)
> >  {
> >         struct device *parent_dev;
> > -       u32 rid_out = rid_in;
> > +       u32 id_out = id_in;
> >
> >         /*
> >          * Walk up the device parent links looking for one with a
> >          * "msi-map" property.
> >          */
> >         for (parent_dev = dev; parent_dev; parent_dev = parent_dev->parent)
> > -               if (!of_map_rid(parent_dev->of_node, rid_in, "msi-map",
> > -                               "msi-map-mask", np, &rid_out))
> > +               if (!of_map_id(parent_dev->of_node, id_in, "msi-map",
> > +                               "msi-map-mask", np, &id_out))
> >                         break;
> > -       return rid_out;
> > +       return id_out;
> >  }
> >
> >  /**
> > - * of_msi_map_rid - Map a MSI requester ID for a device.
> > + * of_msi_map_id - Map a MSI ID for a device.
> >   * @dev: device for which the mapping is to be done.
> >   * @msi_np: device node of the expected msi controller.
> > - * @rid_in: unmapped MSI requester ID for the device.
> > + * @id_in: unmapped MSI ID for the device.
> >   *
> >   * Walk up the device hierarchy looking for devices with a "msi-map"
> > - * property.  If found, apply the mapping to @rid_in.
> > + * property.  If found, apply the mapping to @id_in.
> >   *
> > - * Returns the mapped MSI requester ID.
> > + * Returns the mapped MSI ID.
> >   */
> > -u32 of_msi_map_rid(struct device *dev, struct device_node *msi_np, u32 rid_in)
> > +u32 of_msi_map_id(struct device *dev, struct device_node *msi_np, u32 id_in)
> >  {
> > -       return __of_msi_map_rid(dev, &msi_np, rid_in);
> > +       return __of_msi_map_id(dev, &msi_np, id_in);
> >  }
> >
> >  /**
> >   * of_msi_map_get_device_domain - Use msi-map to find the relevant MSI domain
> >   * @dev: device for which the mapping is to be done.
> > - * @rid: Requester ID for the device.
> > + * @id: Device ID.
> >   * @bus_token: Bus token
> >   *
> >   * Walk up the device hierarchy looking for devices with a "msi-map"
> > @@ -625,7 +625,7 @@ struct irq_domain *of_msi_map_get_device_domain(struct device *dev, u32 id,
> >  {
> >         struct device_node *np = NULL;
> >
> > -       __of_msi_map_rid(dev, &np, id);
> > +       __of_msi_map_id(dev, &np, id);
> >         return irq_find_matching_host(np, bus_token);
> >  }
> >
> > diff --git a/include/linux/of_irq.h b/include/linux/of_irq.h
> > index 7142a3722758..cf9cb1e545ce 100644
> > --- a/include/linux/of_irq.h
> > +++ b/include/linux/of_irq.h
> > @@ -55,7 +55,12 @@ extern struct irq_domain *of_msi_map_get_device_domain(struct device *dev,
> >                                                         u32 id,
> >                                                         u32 bus_token);
> >  extern void of_msi_configure(struct device *dev, struct device_node *np);
> > -u32 of_msi_map_rid(struct device *dev, struct device_node *msi_np, u32 rid_in);
> > +u32 of_msi_map_id(struct device *dev, struct device_node *msi_np, u32 id_in);
> > +static inline u32 of_msi_map_rid(struct device *dev,
> > +                                struct device_node *msi_np, u32 rid_in)
> > +{
> > +       return of_msi_map_id(dev, msi_np, rid_in);
> > +}
> >  #else
> >  static inline int of_irq_count(struct device_node *dev)
> >  {
> > @@ -93,10 +98,15 @@ static inline struct irq_domain *of_msi_map_get_device_domain(struct device *dev
> >  static inline void of_msi_configure(struct device *dev, struct device_node *np)
> >  {
> >  }
> > +static inline u32 of_msi_map_id(struct device *dev,
> > +                                struct device_node *msi_np, u32 id_in)
> > +{
> > +       return id_in;
> > +}
> >  static inline u32 of_msi_map_rid(struct device *dev,
> >                                  struct device_node *msi_np, u32 rid_in)
> 
> Move this out of the ifdef and you only need it declared once.
> 
> But again, I think I'd just kill of_msi_map_rid.

Yes I don't think there is a clear benefit in keeping the _rid
interface.

Thanks,
Lorenzo