Re: [PATCH v2 3/6] of_reserved_mem: add a helper for rmem device_init op

[Albert Esteve]

On Tue, Mar 3, 2026 at 2:13 PM Maxime Ripard <mripard@xxxxxxxxxx> wrote:
>
> On Tue, Mar 03, 2026 at 01:33:46PM +0100, Albert Esteve wrote:
> > Add a helper function wrapping internal reserved memory
> > device_init call and expose it externally.
> >
> > Use the new helper function within of_reserved_mem_device_init_by_idx().
> >
> > Signed-off-by: Albert Esteve <aesteve@xxxxxxxxxx>
> > ---
> >  drivers/of/of_reserved_mem.c    | 27 +++++++++++++++++++++++----
> >  include/linux/of_reserved_mem.h |  8 ++++++++
> >  2 files changed, 31 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/of/of_reserved_mem.c b/drivers/of/of_reserved_mem.c
> > index 1fd28f8056108..3a350bef8f11e 100644
> > --- a/drivers/of/of_reserved_mem.c
> > +++ b/drivers/of/of_reserved_mem.c
> > @@ -605,6 +605,28 @@ struct rmem_assigned_device {
> >  static LIST_HEAD(of_rmem_assigned_device_list);
> >  static DEFINE_MUTEX(of_rmem_assigned_device_mutex);
> >
> > +/**
> > + * of_reserved_mem_device_init_with_mem() - assign reserved memory region to
> > + *                                       given device
> > + * @dev:     Pointer to the device to configure
> > + * @rmem:    Reserved memory region to assign
> > + *
> > + * This function assigns respective DMA-mapping operations based on the
> > + * reserved memory region already provided in @rmem to the @dev device,
> > + * without walking DT nodes.
> > + *
> > + * Returns error code or zero on success.
> > + */
> > +int of_reserved_mem_device_init_with_mem(struct device *dev,
> > +                                      struct reserved_mem *rmem)
> > +{
> > +     if (!dev || !rmem || !rmem->ops || !rmem->ops->device_init)
> > +             return -EINVAL;
> > +
> > +     return rmem->ops->device_init(rmem, dev);
> > +}
> > +EXPORT_SYMBOL_GPL(of_reserved_mem_device_init_with_mem);
> > +
> >  /**
> >   * of_reserved_mem_device_init_by_idx() - assign reserved memory region to
> >   *                                     given device
> > @@ -643,14 +665,11 @@ int of_reserved_mem_device_init_by_idx(struct device *dev,
> >       rmem = of_reserved_mem_lookup(target);
> >       of_node_put(target);
> >
> > -     if (!rmem || !rmem->ops || !rmem->ops->device_init)
> > -             return -EINVAL;
> > -
> >       rd = kmalloc_obj(struct rmem_assigned_device);
> >       if (!rd)
> >               return -ENOMEM;
> >
> > -     ret = rmem->ops->device_init(rmem, dev);
> > +     ret = of_reserved_mem_device_init_with_mem(dev, rmem);
> >       if (ret == 0) {
> >               rd->dev = dev;
> >               rd->rmem = rmem;
>
> I think you need to take the allocation of rd, and everything below.
> Otherwise, your device, despite being attechd, wouldn't be listed
> anywhere.

True, I did not pay enough attention to that part. I will fix it in
the next version.

>
> Maxime