[PATCH 5/7] platform/surface: aggregator_cdev: Allow enabling of events from user-space

Maximilian Luz
2021-06-03T23:47:08Z

While events can already be enabled and disabled via the generic request
IOCTL, this bypasses the internal reference counting mechanism of the
controller. Due to that, disabling an event will turn it off regardless
of any other client having requested said event, which may break
functionality of that client.

To solve this, add IOCTLs wrapping the ssam_controller_event_enable()
and ssam_controller_event_disable() functions, which have been
previously introduced for this specific purpose.

Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
---
.../surface/surface_aggregator_cdev.c | 58 +++++++++++++++++++
include/uapi/linux/surface_aggregator/cdev.h | 32 ++++++++++
2 files changed, 90 insertions(+)

diff --git a/drivers/platform/surface/surface_aggregator_cdev.c b/drivers/platform/surface/surface_aggregator_cdev.c
index 807930144039..e0f3c437b8ee 100644
--- a/drivers/platform/surface/surface_aggregator_cdev.c
+++ b/drivers/platform/surface/surface_aggregator_cdev.c
@@ -387,6 +387,58 @@ static long ssam_cdev_notif_unregister(struct ssam_cdev_client *client,
return ssam_cdev_notifier_unregister(client, desc.target_category);
}

+static long ssam_cdev_event_enable(struct ssam_cdev_client *client,
+ const struct ssam_cdev_event_desc __user *d)
+{
+ struct ssam_cdev_event_desc desc;
+ struct ssam_event_registry reg;
+ struct ssam_event_id id;
+ long ret;
+
+ /* Read descriptor from user-space. */
+ ret = copy_struct_from_user(&desc, sizeof(desc), d, sizeof(*d));
+ if (ret)
+ return ret;
+
+ /* Translate descriptor. */
+ reg.target_category = desc.reg.target_category;
+ reg.target_id = desc.reg.target_id;
+ reg.cid_enable = desc.reg.cid_enable;
+ reg.cid_disable = desc.reg.cid_disable;
+
+ id.target_category = desc.id.target_category;
+ id.instance = desc.id.instance;
+
+ /* Disable event. */
+ return ssam_controller_event_enable(client->cdev->ctrl, reg, id, desc.flags);
+}
+
+static long ssam_cdev_event_disable(struct ssam_cdev_client *client,
+ const struct ssam_cdev_event_desc __user *d)
+{
+ struct ssam_cdev_event_desc desc;
+ struct ssam_event_registry reg;
+ struct ssam_event_id id;
+ long ret;
+
+ /* Read descriptor from user-space. */
+ ret = copy_struct_from_user(&desc, sizeof(desc), d, sizeof(*d));
+ if (ret)
+ return ret;
+
+ /* Translate descriptor. */
+ reg.target_category = desc.reg.target_category;
+ reg.target_id = desc.reg.target_id;
+ reg.cid_enable = desc.reg.cid_enable;
+ reg.cid_disable = desc.reg.cid_disable;
+
+ id.target_category = desc.id.target_category;
+ id.instance = desc.id.instance;
+
+ /* Disable event. */
+ return ssam_controller_event_disable(client->cdev->ctrl, reg, id, desc.flags);
+}
+

/* -- File operations. ------------------------------------------------------ */

@@ -470,6 +522,12 @@ static long __ssam_cdev_device_ioctl(struct ssam_cdev_client *client, unsigned i
return ssam_cdev_notif_unregister(client,
(struct ssam_cdev_notifier_desc __user *)arg);

+ case SSAM_CDEV_EVENT_ENABLE:
+ return ssam_cdev_event_enable(client, (struct ssam_cdev_event_desc __user *)arg);
+
+ case SSAM_CDEV_EVENT_DISABLE:
+ return ssam_cdev_event_disable(client, (struct ssam_cdev_event_desc __user *)arg);
+
default:
return -ENOTTY;
}
diff --git a/include/uapi/linux/surface_aggregator/cdev.h b/include/uapi/linux/surface_aggregator/cdev.h
index 4f393fafc235..08f46b60b151 100644
--- a/include/uapi/linux/surface_aggregator/cdev.h
+++ b/include/uapi/linux/surface_aggregator/cdev.h
@@ -90,6 +90,36 @@ struct ssam_cdev_notifier_desc {
__u8 target_category;
} __attribute__((__packed__));

+/**
+ * struct ssam_cdev_event_desc - Event descriptor.
+ * @reg: Registry via which the event will be enabled/disabled.
+ * @reg.target_category: Target category for the event registry requests.
+ * @reg.target_id: Target ID for the event registry requests.
+ * @reg.cid_enable: Command ID for the event-enable request.
+ * @reg.cid_disable: Command ID for the event-disable request.
+ * @id: ID specifying the event.
+ * @id.target_category: Target category of the event source.
+ * @id.instance: Instance ID of the event source.
+ * @flags: Flags used for enabling the event.
+ *
+ * Specifies which event should be enabled/disabled and how to do that.
+ */
+struct ssam_cdev_event_desc {
+ struct {
+ __u8 target_category;
+ __u8 target_id;
+ __u8 cid_enable;
+ __u8 cid_disable;
+ } reg;
+
+ struct {
+ __u8 target_category;
+ __u8 instance;
+ } id;
+
+ __u8 flags;
+} __attribute__((__packed__));
+
/**
* struct ssam_cdev_event - SSAM event sent by the EC.
* @target_category: Target category of the event source. See &enum ssam_ssh_tc.
@@ -111,5 +141,7 @@ struct ssam_cdev_event {
#define SSAM_CDEV_REQUEST _IOWR(0xA5, 1, struct ssam_cdev_request)
#define SSAM_CDEV_NOTIF_REGISTER _IOW(0xA5, 2, struct ssam_cdev_notifier_desc)
#define SSAM_CDEV_NOTIF_UNREGISTER _IOW(0xA5, 3, struct ssam_cdev_notifier_desc)
+#define SSAM_CDEV_EVENT_ENABLE _IOW(0xA5, 4, struct ssam_cdev_event_desc)
+#define SSAM_CDEV_EVENT_DISABLE _IOW(0xA5, 5, struct ssam_cdev_event_desc)

#endif /* _UAPI_LINUX_SURFACE_AGGREGATOR_CDEV_H */
--
2.31.1