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@redhat.com>
---
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;
diff --git a/include/linux/of_reserved_mem.h b/include/linux/of_reserved_mem.h
index f573423359f48..12f7ddb7ee61f 100644
--- a/include/linux/of_reserved_mem.h
+++ b/include/linux/of_reserved_mem.h
@@ -32,6 +32,8 @@ typedef int (*reservedmem_of_init_fn)(struct reserved_mem *rmem);
#define RESERVEDMEM_OF_DECLARE(name, compat, init) \
_OF_DECLARE(reservedmem, name, compat, init, reservedmem_of_init_fn)
+int of_reserved_mem_device_init_with_mem(struct device *dev,
+ struct reserved_mem *rmem);
int of_reserved_mem_device_init_by_idx(struct device *dev,
struct device_node *np, int idx);
int of_reserved_mem_device_init_by_name(struct device *dev,
@@ -51,6 +53,12 @@ int of_reserved_mem_region_count(const struct device_node *np);
#define RESERVEDMEM_OF_DECLARE(name, compat, init) \
_OF_DECLARE_STUB(reservedmem, name, compat, init, reservedmem_of_init_fn)
+static inline int of_reserved_mem_device_init_with_mem(struct device *dev,
+ struct reserved_mem *rmem)
+{
+ return -EOPNOTSUPP;
+}
+
static inline int of_reserved_mem_device_init_by_idx(struct device *dev,
struct device_node *np, int idx)
{
--
2.52.0On 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@redhat.com>
> ---
> 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.
Maxime
On Tue, Mar 3, 2026 at 2:13 PM Maxime Ripard <mripard@redhat.com> 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@redhat.com>
> > ---
> > 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
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