[PATCH v6 06/37] firmware: arm_scmi: introduce new devres notification ops

Cristian Marussi
2021-02-02T22:18:25Z

Expose to the SCMI drivers a new alternative devres managed notifications
API based on protocol handles.

All drivers still keep using the old API, no functional change.

Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
---
drivers/firmware/arm_scmi/notify.c | 123 +++++++++++++++++++++++++++++
include/linux/scmi_protocol.h | 15 +++-
2 files changed, 137 insertions(+), 1 deletion(-)

diff --git a/drivers/firmware/arm_scmi/notify.c b/drivers/firmware/arm_scmi/notify.c
index cdaf0f962d84..70e8eb4e33c6 100644
--- a/drivers/firmware/arm_scmi/notify.c
+++ b/drivers/firmware/arm_scmi/notify.c
@@ -1408,6 +1408,127 @@ static int scmi_unregister_notifier(const struct scmi_handle *handle,
return 0;
}

+struct scmi_notifier_devres {
+ const struct scmi_handle *handle;
+ u8 proto_id;
+ u8 evt_id;
+ u32 __src_id;
+ u32 *src_id;
+ struct notifier_block *nb;
+};
+
+static void scmi_devm_release_notifier(struct device *dev, void *res)
+{
+ struct scmi_notifier_devres *dres = res;
+
+ scmi_unregister_notifier(dres->handle, dres->proto_id, dres->evt_id,
+ dres->src_id, dres->nb);
+}
+
+/**
+ * scmi_devm_register_notifier() - Managed registration of a notifier_block
+ * for an event
+ * @sdev: A reference to an scmi_device whose embedded struct device is to
+ * be used for devres accounting.
+ * @proto_id: Protocol ID
+ * @evt_id: Event ID
+ * @src_id: Source ID, when NULL register for events coming form ALL possible
+ * sources
+ * @nb: A standard notifier block to register for the specified event
+ *
+ * Generic devres managed helper to register a notifier_block against a
+ * protocol event.
+ */
+static int scmi_devm_register_notifier(struct scmi_device *sdev,
+ u8 proto_id, u8 evt_id, u32 *src_id,
+ struct notifier_block *nb)
+{
+ int ret;
+ struct scmi_notifier_devres *dres;
+
+ dres = devres_alloc(scmi_devm_release_notifier,
+ sizeof(*dres), GFP_KERNEL);
+ if (!dres)
+ return -ENOMEM;
+
+ ret = scmi_register_notifier(sdev->handle, proto_id,
+ evt_id, src_id, nb);
+ if (ret) {
+ devres_free(dres);
+ return ret;
+ }
+
+ dres->handle = sdev->handle;
+ dres->proto_id = proto_id;
+ dres->evt_id = evt_id;
+ dres->nb = nb;
+ if (src_id) {
+ dres->__src_id = *src_id;
+ dres->src_id = &dres->__src_id;
+ } else {
+ dres->src_id = NULL;
+ }
+ devres_add(&sdev->dev, dres);
+
+ return ret;
+}
+
+static int scmi_devm_notifier_match(struct device *dev, void *res, void *data)
+{
+ struct scmi_notifier_devres *dres = res;
+ struct scmi_notifier_devres *xres = data;
+
+ if (WARN_ON(!dres || !xres))
+ return 0;
+
+ return dres->proto_id == xres->proto_id &&
+ dres->evt_id == xres->evt_id &&
+ dres->nb == xres->nb &&
+ ((!dres->src_id && !xres->src_id) ||
+ (dres->src_id && xres->src_id &&
+ dres->__src_id == xres->__src_id));
+}
+
+/**
+ * scmi_devm_unregister_notifier() - Managed un-registration of a
+ * notifier_block for an event
+ * @sdev: A reference to an scmi_device whose embedded struct device is to
+ * be used for devres accounting.
+ * @proto_id: Protocol ID
+ * @evt_id: Event ID
+ * @src_id: Source ID, when NULL register for events coming form ALL possible
+ * sources
+ * @nb: A standard notifier block to register for the specified event
+ *
+ * Generic devres managed helper to explicitly un-register a notifier_block
+ * against a protocol event, which was previously registered using the above
+ * @scmi_devm_register_notifier.
+ */
+static int scmi_devm_unregister_notifier(struct scmi_device *sdev,
+ u8 proto_id, u8 evt_id, u32 *src_id,
+ struct notifier_block *nb)
+{
+ int ret;
+ struct scmi_notifier_devres dres;
+
+ dres.handle = sdev->handle;
+ dres.proto_id = proto_id;
+ dres.evt_id = evt_id;
+ if (src_id) {
+ dres.__src_id = *src_id;
+ dres.src_id = &dres.__src_id;
+ } else {
+ dres.src_id = NULL;
+ }
+
+ ret = devres_release(&sdev->dev, scmi_devm_release_notifier,
+ scmi_devm_notifier_match, &dres);
+
+ WARN_ON(ret);
+
+ return ret;
+}
+
/**
* scmi_protocols_late_init() - Worker for late initialization
* @work: The work item to use associated to the proper SCMI instance
@@ -1465,6 +1586,8 @@ static void scmi_protocols_late_init(struct work_struct *work)
* directly from an scmi_driver to register its own notifiers.
*/
static const struct scmi_notify_ops notify_ops = {
+ .devm_register_event_notifier = scmi_devm_register_notifier,
+ .devm_unregister_event_notifier = scmi_devm_unregister_notifier,
.register_event_notifier = scmi_register_notifier,
.unregister_event_notifier = scmi_unregister_notifier,
};
diff --git a/include/linux/scmi_protocol.h b/include/linux/scmi_protocol.h
index b3ca2969c29a..2bb0c53bf4c5 100644
--- a/include/linux/scmi_protocol.h
+++ b/include/linux/scmi_protocol.h
@@ -544,6 +544,10 @@ struct scmi_voltage_ops {
/**
* struct scmi_notify_ops - represents notifications' operations provided by
* SCMI core
+ * @devm_register_event_notifier: Managed registration of a notifier_block for
+ * the requested event
+ * @devm_unregister_event_notifier: Managed unregistration of a notifier_block
+ * for the requested event
* @register_event_notifier: Register a notifier_block for the requested event
* @unregister_event_notifier: Unregister a notifier_block for the requested
* event
@@ -553,7 +557,9 @@ struct scmi_voltage_ops {
* tuple: (proto_id, evt_id, src_id) using the provided register/unregister
* interface where:
*
- * @handle: The handle identifying the platform instance to use
+ * @sdev: The scmi_device to use when calling the devres managed ops devm_
+ * @handle: The handle identifying the platform instance to use, when not
+ * calling the managed ops devm_
* @proto_id: The protocol ID as in SCMI Specification
* @evt_id: The message ID of the desired event as in SCMI Specification
* @src_id: A pointer to the desired source ID if different sources are
@@ -576,6 +582,13 @@ struct scmi_voltage_ops {
* @report: A custom struct describing the specific event delivered
*/
struct scmi_notify_ops {
+ int (*devm_register_event_notifier)(struct scmi_device *sdev,
+ u8 proto_id, u8 evt_id, u32 *src_id,
+ struct notifier_block *nb);
+ int (*devm_unregister_event_notifier)(struct scmi_device *sdev,
+ u8 proto_id, u8 evt_id,
+ u32 *src_id,
+ struct notifier_block *nb);
int (*register_event_notifier)(const struct scmi_handle *handle,
u8 proto_id, u8 evt_id, u32 *src_id,
struct notifier_block *nb);
--
2.17.1