habanalabs: add support for notification via eventfd

The driver will be able to send notification events towards
a user process, using user's registered event file descriptor.
The driver uses the notification mechanism to inform the
user about an occurred event.
A user thread can wait until a notification is received from
the driver.

The driver stores the occurred event until the user reads it,
using HL_INFO_GET_EVENTS - new ioctl opcode in the INFO ioctl.

Gaudi specific implementation includes sending a notification
on a TPC assertion event that is received from f/w.

Signed-off-by: Tal Cohen <talcohen@habana.ai>
Reviewed-by: Oded Gabbay <ogabbay@kernel.org>
Signed-off-by: Oded Gabbay <ogabbay@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 52 insertions, 0 deletions

diff --git a/drivers/misc/habanalabs/common/device.c b/drivers/misc/habanalabs/common/device.c
index 15df89b31e1b..315510aaca35 100644
--- a/drivers/misc/habanalabs/common/device.c
+++ b/drivers/misc/habanalabs/common/device.c
@@ -285,6 +285,14 @@ static void hpriv_release(struct kref *ref)
 
 	hdev->compute_ctx_in_release = 0;
 
+	/* release the eventfd */
+	if (hpriv->notifier_event.eventfd) {
+		eventfd_ctx_put(hpriv->notifier_event.eventfd);
+		hpriv->notifier_event.eventfd = 0;
+	}
+
+	mutex_destroy(&hpriv->notifier_event.lock);
+
 	kfree(hpriv);
 }
 
@@ -355,6 +363,13 @@ static int hl_device_release_ctrl(struct inode *inode, struct file *filp)
 	list_del(&hpriv->dev_node);
 	mutex_unlock(&hdev->fpriv_ctrl_list_lock);
 out:
+	/* release the eventfd */
+	if (hpriv->notifier_event.eventfd) {
+		eventfd_ctx_put(hpriv->notifier_event.eventfd);
+		hpriv->notifier_event.eventfd = 0;
+	}
+
+	mutex_destroy(&hpriv->notifier_event.lock);
 	put_pid(hpriv->taskpid);
 
 	kfree(hpriv);
@@ -1506,6 +1521,43 @@ out_err:
 	return rc;
 }
 
+static void hl_notifier_event_send(struct hl_notifier_event *notifier_event, u64 event)
+{
+	mutex_lock(&notifier_event->lock);
+	notifier_event->events_mask |= event;
+	if (notifier_event->eventfd)
+		eventfd_signal(notifier_event->eventfd, 1);
+
+	mutex_unlock(&notifier_event->lock);
+}
+
+/*
+ * hl_notifier_event_send_all - notify all user processes via eventfd
+ *
+ * @hdev: pointer to habanalabs device structure
+ * @event: the occurred event
+ * Returns 0 for success or an error on failure.
+ */
+void hl_notifier_event_send_all(struct hl_device *hdev, u64 event)
+{
+	struct hl_fpriv	*hpriv;
+
+	mutex_lock(&hdev->fpriv_list_lock);
+
+	list_for_each_entry(hpriv, &hdev->fpriv_list, dev_node)
+		hl_notifier_event_send(&hpriv->notifier_event, event);
+
+	mutex_unlock(&hdev->fpriv_list_lock);
+
+	/* control device */
+	mutex_lock(&hdev->fpriv_ctrl_list_lock);
+
+	list_for_each_entry(hpriv, &hdev->fpriv_ctrl_list, dev_node)
+		hl_notifier_event_send(&hpriv->notifier_event, event);
+
+	mutex_unlock(&hdev->fpriv_ctrl_list_lock);
+}
+
 /*
  * hl_device_init - main initialization function for habanalabs device
  *