This patch add of overlay notifications.
When DT overlays are being added, some drivers/subsystems
need to see device tree overlays before the changes go into
the live tree.
This is distinct from reconfig notifiers that are
post-apply or post-remove and which issue very granular
notifications without providing access to the context
of a whole overlay.
The following 4 notificatons are issued:
OF_OVERLAY_PRE_APPLY
OF_OVERLAY_POST_APPLY
OF_OVERLAY_PRE_REMOVE
OF_OVERLAY_POST_REMOVE
In the case of pre-apply notification, if the notifier
returns error, the overlay will be rejected.
This patch exports two functions for registering/unregistering
notifications:
of_overlay_notifier_register(struct notifier_block *nb)
of_overlay_notifier_unregister(struct notifier_block *nb)
The notification data includes pointers to the overlay
target and the overlay:
struct of_overlay_notify_data {
struct device_node *overlay;
struct device_node *target;
};
Signed-off-by: Alan Tull <atull@xxxxxxxxxxxxxxxxxxxxx>
---
v2: add missing 'static inline' in of.h
---
drivers/of/overlay.c | 47 ++++++++++++++++++++++++++++++++++++++++++++++-
include/linux/of.h | 25 +++++++++++++++++++++++++
2 files changed, 71 insertions(+), 1 deletion(-)
diff --git a/drivers/of/overlay.c b/drivers/of/overlay.c
index 8225081..a26f0ed 100644
--- a/drivers/of/overlay.c
+++ b/drivers/of/overlay.c
@@ -56,6 +56,41 @@ struct of_overlay {
static int of_overlay_apply_one(struct of_overlay *ov,
struct device_node *target, const struct device_node *overlay);
+static BLOCKING_NOTIFIER_HEAD(of_overlay_chain);
+
+int of_overlay_notifier_register(struct notifier_block *nb)
+{
+ return blocking_notifier_chain_register(&of_overlay_chain, nb);
+}
+EXPORT_SYMBOL_GPL(of_overlay_notifier_register);
+
+int of_overlay_notifier_unregister(struct notifier_block *nb)
+{
+ return blocking_notifier_chain_unregister(&of_overlay_chain, nb);
+}
+EXPORT_SYMBOL_GPL(of_overlay_notifier_unregister);
+
+static int of_overlay_notify(struct of_overlay *ov,
+ enum of_overlay_notify_action action)
+{
+ struct of_overlay_notify_data nd;
+ int i, ret;
+
+ for (i = 0; i < ov->count; i++) {
+ struct of_overlay_info *ovinfo = &ov->ovinfo_tab[i];
+
+ nd.target = ovinfo->target;
+ nd.overlay = ovinfo->overlay;
+
+ ret = blocking_notifier_call_chain(&of_overlay_chain,
+ action, &nd);
+ if (ret)
+ return notifier_to_errno(ret);
+ }
+
+ return 0;
+}
+
static int of_overlay_apply_single_property(struct of_overlay *ov,
struct device_node *target, struct property *prop)
{
@@ -370,6 +405,13 @@ int of_overlay_create(struct device_node *tree)
goto err_free_idr;
}
+ err = of_overlay_notify(ov, OF_OVERLAY_PRE_APPLY);
+ if (err < 0) {
+ pr_err("%s: Pre-apply notifier failed (err=%d)\n",
+ __func__, err);
+ goto err_free_idr;
+ }
+
/* apply the overlay */
err = of_overlay_apply(ov);
if (err) {
@@ -389,6 +431,8 @@ int of_overlay_create(struct device_node *tree)
/* add to the tail of the overlay list */
list_add_tail(&ov->node, &ov_list);
+ of_overlay_notify(ov, OF_OVERLAY_POST_APPLY);
+
mutex_unlock(&of_mutex);
return id;
@@ -509,9 +553,10 @@ int of_overlay_destroy(int id)
goto out;
}
-
+ of_overlay_notify(ov, OF_OVERLAY_PRE_REMOVE);
list_del(&ov->node);
__of_changeset_revert(&ov->cset);
+ of_overlay_notify(ov, OF_OVERLAY_POST_REMOVE);
of_free_overlay_info(ov);
idr_remove(&ov_idr, id);
of_changeset_destroy(&ov->cset);
diff --git a/include/linux/of.h b/include/linux/of.h
index dc6e396..b79e1c5 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -1083,6 +1083,21 @@ int of_overlay_create(struct device_node *tree);
int of_overlay_destroy(int id);
int of_overlay_destroy_all(void);
+enum of_overlay_notify_action {
+ OF_OVERLAY_PRE_APPLY,
+ OF_OVERLAY_POST_APPLY,
+ OF_OVERLAY_PRE_REMOVE,
+ OF_OVERLAY_POST_REMOVE,
+};
+
+struct of_overlay_notify_data {
+ struct device_node *overlay;
+ struct device_node *target;
+};
+
+int of_overlay_notifier_register(struct notifier_block *nb);
+int of_overlay_notifier_unregister(struct notifier_block *nb);
+
#else
static inline int of_overlay_create(struct device_node *tree)
@@ -1100,6 +1115,16 @@ static inline int of_overlay_destroy_all(void)
return -ENOTSUPP;
}
+static inline int of_overlay_notifier_register(struct notifier_block *nb)
+{
+ return 0;
+}
+
+static inline int of_overlay_notifier_unregister(struct notifier_block *nb)
+{
+ return 0;
+}
+
#endif
#endif /* _LINUX_OF_H */
--
1.7.9.5
--
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