[PATCH v6 35/37] firmware: arm_scmi: make notify_priv really private

Cristian Marussi
2021-02-02T22:26:43Z

Notification private data is currently accessible via handle->notify_priv;
this data was indeed meant to be private to the notification core support
and not to be accessible by SCMI drivers: make it private hiding it inside
instance descriptor struct scmi_info and accessible only via dedicated
helpers.

Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
---
drivers/firmware/arm_scmi/common.h | 4 +++
drivers/firmware/arm_scmi/driver.c | 21 ++++++++++++++
drivers/firmware/arm_scmi/notify.c | 45 ++++++++++--------------------
include/linux/scmi_protocol.h | 3 --
4 files changed, 40 insertions(+), 33 deletions(-)

diff --git a/drivers/firmware/arm_scmi/common.h b/drivers/firmware/arm_scmi/common.h
index 65db0aefc489..5fb64182610a 100644
--- a/drivers/firmware/arm_scmi/common.h
+++ b/drivers/firmware/arm_scmi/common.h
@@ -341,4 +341,8 @@ void shmem_clear_channel(struct scmi_shared_mem __iomem *shmem);
bool shmem_poll_done(struct scmi_shared_mem __iomem *shmem,
struct scmi_xfer *xfer);

+void scmi_set_notification_instance_data(const struct scmi_handle *handle,
+ void *priv);
+void *scmi_get_notification_instance_data(const struct scmi_handle *handle);
+
#endif /* _SCMI_COMMON_H */
diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c
index 0a544463d0a2..159d3fa2b9b6 100644
--- a/drivers/firmware/arm_scmi/driver.c
+++ b/drivers/firmware/arm_scmi/driver.c
@@ -113,6 +113,7 @@ struct scmi_protocol_instance {
* @protocols_mtx: A mutex to protect protocols instances initialization.
* @protocols_imp: List of protocols implemented, currently maximum of
* MAX_PROTOCOLS_IMP elements allocated by the base protocol
+ * @notify_priv: Pointer to private data structure specific to notifications.
* @node: List head
* @users: Number of users of this instance
*/
@@ -129,6 +130,7 @@ struct scmi_info {
/* Ensure mutual exclusive access to protocols instance array */
struct mutex protocols_mtx;
u8 *protocols_imp;
+ void *notify_priv;
struct list_head node;
int users;
};
@@ -170,6 +172,25 @@ static inline void scmi_dump_header_dbg(struct device *dev,
hdr->id, hdr->seq, hdr->protocol_id);
}

+void scmi_set_notification_instance_data(const struct scmi_handle *handle,
+ void *priv)
+{
+ struct scmi_info *info = handle_to_scmi_info(handle);
+
+ info->notify_priv = priv;
+ /* Ensure updated protocol private date are visible */
+ smp_wmb();
+}
+
+void *scmi_get_notification_instance_data(const struct scmi_handle *handle)
+{
+ struct scmi_info *info = handle_to_scmi_info(handle);
+
+ /* Ensure protocols_private_data has been updated */
+ smp_rmb();
+ return info->notify_priv;
+}
+
/**
* scmi_xfer_get() - Allocate one message
*
diff --git a/drivers/firmware/arm_scmi/notify.c b/drivers/firmware/arm_scmi/notify.c
index d88bc9960c7c..39374255b3a7 100644
--- a/drivers/firmware/arm_scmi/notify.c
+++ b/drivers/firmware/arm_scmi/notify.c
@@ -582,11 +582,9 @@ int scmi_notify(const struct scmi_handle *handle, u8 proto_id, u8 evt_id,
struct scmi_event_header eh;
struct scmi_notify_instance *ni;

- /* Ensure notify_priv is updated */
- smp_rmb();
- if (!handle->notify_priv)
+ ni = scmi_get_notification_instance_data(handle);
+ if (!ni)
return 0;
- ni = handle->notify_priv;

r_evt = SCMI_GET_REVT(ni, proto_id, evt_id);
if (!r_evt)
@@ -762,11 +760,9 @@ int scmi_register_protocol_events(const struct scmi_handle *handle, u8 proto_id,
(!ee->num_sources && !ee->ops->get_num_sources))
return -EINVAL;

- /* Ensure notify_priv is updated */
- smp_rmb();
- if (!handle->notify_priv)
+ ni = scmi_get_notification_instance_data(handle);
+ if (!ni)
return -ENOMEM;
- ni = handle->notify_priv;

/* num_sources cannot be <= 0 */
if (ee->num_sources) {
@@ -851,12 +847,10 @@ void scmi_deregister_protocol_events(const struct scmi_handle *handle,
struct scmi_notify_instance *ni;
struct scmi_registered_events_desc *pd;

- /* Ensure notify_priv is updated */
- smp_rmb();
- if (!handle->notify_priv)
+ ni = scmi_get_notification_instance_data(handle);
+ if (!ni)
return;

- ni = handle->notify_priv;
pd = ni->registered_protocols[proto_id];
if (!pd)
return;
@@ -1359,11 +1353,9 @@ static int scmi_register_notifier(const struct scmi_handle *handle,
struct scmi_event_handler *hndl;
struct scmi_notify_instance *ni;

- /* Ensure notify_priv is updated */
- smp_rmb();
- if (!handle->notify_priv)
+ ni = scmi_get_notification_instance_data(handle);
+ if (!ni)
return -ENODEV;
- ni = handle->notify_priv;

evt_key = MAKE_HASH_KEY(proto_id, evt_id,
src_id ? *src_id : SRC_ID_MASK);
@@ -1407,11 +1399,9 @@ static int scmi_unregister_notifier(const struct scmi_handle *handle,
struct scmi_event_handler *hndl;
struct scmi_notify_instance *ni;

- /* Ensure notify_priv is updated */
- smp_rmb();
- if (!handle->notify_priv)
+ ni = scmi_get_notification_instance_data(handle);
+ if (!ni)
return -ENODEV;
- ni = handle->notify_priv;

evt_key = MAKE_HASH_KEY(proto_id, evt_id,
src_id ? *src_id : SRC_ID_MASK);
@@ -1684,8 +1674,8 @@ int scmi_notification_init(struct scmi_handle *handle)

INIT_WORK(&ni->init_work, scmi_protocols_late_init);

+ scmi_set_notification_instance_data(handle, ni);
handle->notify_ops = &notify_ops;
- handle->notify_priv = ni;
/* Ensure handle is up to date */
smp_wmb();

@@ -1697,7 +1687,7 @@ int scmi_notification_init(struct scmi_handle *handle)

err:
dev_warn(handle->dev, "Initialization Failed.\n");
- devres_release_group(handle->dev, NULL);
+ devres_release_group(handle->dev, gid);
return -ENOMEM;
}

@@ -1709,15 +1699,10 @@ void scmi_notification_exit(struct scmi_handle *handle)
{
struct scmi_notify_instance *ni;

- /* Ensure notify_priv is updated */
- smp_rmb();
- if (!handle->notify_priv)
+ ni = scmi_get_notification_instance_data(handle);
+ if (!ni)
return;
- ni = handle->notify_priv;
-
- handle->notify_priv = NULL;
- /* Ensure handle is up to date */
- smp_wmb();
+ scmi_set_notification_instance_data(handle, NULL);

/* Destroy while letting pending work complete */
destroy_workqueue(ni->notify_wq);
diff --git a/include/linux/scmi_protocol.h b/include/linux/scmi_protocol.h
index 58008b294e3b..51ec4dc4fd6a 100644
--- a/include/linux/scmi_protocol.h
+++ b/include/linux/scmi_protocol.h
@@ -612,8 +612,6 @@ struct scmi_notify_ops {
* @devm_put_protocol: devres managed method to release a protocol acquired
* with devm_acquire/get_protocol
* @notify_ops: pointer to set of notifications related operations
- * @notify_priv: pointer to private data structure specific to notifications
- * (for internal use only)
*/
struct scmi_handle {
struct device *dev;
@@ -627,7 +625,6 @@ struct scmi_handle {
void (*devm_put_protocol)(struct scmi_device *sdev, u8 proto);

const struct scmi_notify_ops *notify_ops;
- void *notify_priv;
};

enum scmi_std_protocol {
--
2.17.1