gpu: host1x: Add early init and late exit callbacks

These callbacks can be used by client drivers to run code during early
init and during late exit. Early init callbacks are run prior to the
regular init callbacks while late exit callbacks run after the regular
exit callbacks.
Signed-off-by: Thierry Reding <treding@nvidia.com>

drivers/gpu/host1x/bus.c

@@ -196,6 +196,17 @@ int host1x_device_init(struct host1x_device *device)
 
 	mutex_lock(&device->clients_lock);
 
+	list_for_each_entry(client, &device->clients, list) {
+		if (client->ops && client->ops->early_init) {
+			err = client->ops->early_init(client);
+			if (err < 0) {
+				dev_err(&device->dev, "failed to early initialize %s: %d\n",
+					dev_name(client->dev), err);
+				goto teardown_late;
+			}
+		}
+	}
+
 	list_for_each_entry(client, &device->clients, list) {
 		if (client->ops && client->ops->init) {
 			err = client->ops->init(client);
@@ -217,6 +228,14 @@ int host1x_device_init(struct host1x_device *device)
 		if (client->ops->exit)
 			client->ops->exit(client);
 
+	/* reset client to end of list for late teardown */
+	client = list_entry(&device->clients, struct host1x_client, list);
+
+teardown_late:
+	list_for_each_entry_continue_reverse(client, &device->clients, list)
+		if (client->ops->late_exit)
+			client->ops->late_exit(client);
+
 	mutex_unlock(&device->clients_lock);
 	return err;
 }
@@ -251,6 +270,18 @@ int host1x_device_exit(struct host1x_device *device)
 		}
 	}
 
+	list_for_each_entry_reverse(client, &device->clients, list) {
+		if (client->ops && client->ops->late_exit) {
+			err = client->ops->late_exit(client);
+			if (err < 0) {
+				dev_err(&device->dev, "failed to late cleanup %s: %d\n",
+					dev_name(client->dev), err);
+				mutex_unlock(&device->clients_lock);
+				return err;
+			}
+		}
+	}
+
 	mutex_unlock(&device->clients_lock);
 
 	return 0;

include/linux/host1x.h

@@ -25,14 +25,18 @@ u64 host1x_get_dma_mask(struct host1x *host1x);
 
 /**
  * struct host1x_client_ops - host1x client operations
+ * @early_init: host1x client early initialization code
  * @init: host1x client initialization code
  * @exit: host1x client tear down code
+ * @late_exit: host1x client late tear down code
  * @suspend: host1x client suspend code
  * @resume: host1x client resume code
  */
 struct host1x_client_ops {
+	int (*early_init)(struct host1x_client *client);
 	int (*init)(struct host1x_client *client);
 	int (*exit)(struct host1x_client *client);
+	int (*late_exit)(struct host1x_client *client);
 	int (*suspend)(struct host1x_client *client);
 	int (*resume)(struct host1x_client *client);
 };