bus/fsl-mc: Export a cleanup function for DPRC

Create and export a cleanup function for DPRC. The function
is used by the DPRC driver, but it will be used by the VFIO
driver as well.
Reviewed-by: Laurentiu Tudor <laurentiu.tudor@nxp.com>
Acked-by: Laurentiu Tudor <laurentiu.tudor@nxp.com>
Signed-off-by: Diana Craciun <diana.craciun@oss.nxp.com>
Link: https://lore.kernel.org/r/20200929085441.17448-9-diana.craciun@oss.nxp.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/bus/fsl-mc/dprc-driver.c

@@ -728,33 +728,26 @@ static void dprc_teardown_irq(struct fsl_mc_device *mc_dev)
 }
 
 /**
- * dprc_remove - callback invoked when a DPRC is being unbound from this driver
+ * dprc_cleanup - function that cleanups a DPRC
  *
  * @mc_dev: Pointer to fsl-mc device representing the DPRC
  *
- * It removes the DPRC's child objects from Linux (not from the MC) and
- * closes the DPRC device in the MC.
- * It tears down the interrupts that were configured for the DPRC device.
+ * It closes the DPRC device in the MC.
  * It destroys the interrupt pool associated with this MC bus.
  */
-static int dprc_remove(struct fsl_mc_device *mc_dev)
+
+int dprc_cleanup(struct fsl_mc_device *mc_dev)
 {
 	int error;
 	struct fsl_mc_bus *mc_bus = to_fsl_mc_bus(mc_dev);
 
-	if (!is_fsl_mc_bus_dprc(mc_dev))
-		return -EINVAL;
-	if (!mc_dev->mc_io)
-		return -EINVAL;
 
-	if (!mc_bus->irq_resources)
+	/* this function should be called only for DPRCs, it
+	 * is an error to call it for regular objects
+	 */
+	if (!is_fsl_mc_bus_dprc(mc_dev))
 		return -EINVAL;
 
-	if (dev_get_msi_domain(&mc_dev->dev))
-		dprc_teardown_irq(mc_dev);
-
-	device_for_each_child(&mc_dev->dev, NULL, __fsl_mc_device_remove);
-
 	if (dev_get_msi_domain(&mc_dev->dev)) {
 		fsl_mc_cleanup_irq_pool(mc_bus);
 		dev_set_msi_domain(&mc_dev->dev, NULL);
@@ -762,6 +755,14 @@ static int dprc_remove(struct fsl_mc_device *mc_dev)
 
 	fsl_mc_cleanup_all_resource_pools(mc_dev);
 
+	/* if this step fails we cannot go further with cleanup as there is no way of
+	 * communicating with the firmware
+	 */
+	if (!mc_dev->mc_io) {
+		dev_err(&mc_dev->dev, "mc_io is NULL, tear down cannot be performed in firmware\n");
+		return -EINVAL;
+	}
+
 	error = dprc_close(mc_dev->mc_io, 0, mc_dev->mc_handle);
 	if (error < 0)
 		dev_err(&mc_dev->dev, "dprc_close() failed: %d\n", error);
@@ -771,6 +772,37 @@ static int dprc_remove(struct fsl_mc_device *mc_dev)
 		mc_dev->mc_io = NULL;
 	}
 
+	return 0;
+}
+EXPORT_SYMBOL_GPL(dprc_cleanup);
+
+/**
+ * dprc_remove - callback invoked when a DPRC is being unbound from this driver
+ *
+ * @mc_dev: Pointer to fsl-mc device representing the DPRC
+ *
+ * It removes the DPRC's child objects from Linux (not from the MC) and
+ * closes the DPRC device in the MC.
+ * It tears down the interrupts that were configured for the DPRC device.
+ * It destroys the interrupt pool associated with this MC bus.
+ */
+static int dprc_remove(struct fsl_mc_device *mc_dev)
+{
+	struct fsl_mc_bus *mc_bus = to_fsl_mc_bus(mc_dev);
+
+	if (!is_fsl_mc_bus_dprc(mc_dev))
+		return -EINVAL;
+
+	if (!mc_bus->irq_resources)
+		return -EINVAL;
+
+	if (dev_get_msi_domain(&mc_dev->dev))
+		dprc_teardown_irq(mc_dev);
+
+	device_for_each_child(&mc_dev->dev, NULL, __fsl_mc_device_remove);
+
+	dprc_cleanup(mc_dev);
+
 	dev_info(&mc_dev->dev, "DPRC device unbound from driver");
 	return 0;
 }

include/linux/fsl/mc.h

@@ -538,6 +538,8 @@ void dprc_remove_devices(struct fsl_mc_device *mc_bus_dev,
 			 struct fsl_mc_obj_desc *obj_desc_array,
 			 int num_child_objects_in_mc);
 
+int dprc_cleanup(struct fsl_mc_device *mc_dev);
+
 /*
  * Data Path Buffer Pool (DPBP) API
  * Contains initialization APIs and runtime control APIs for DPBP