[PATCH v4 3/7] staging: fsl-mc: Propagate driver_override for a child DPRC's children

["J. German Rivera" <German.Rivera@freescale.com>]

When a child DPRC is bound to the vfio_fsl_mc driver via driver_override,
its own children should not be bound to corresponding host kernel
drivers, but instead should be bound to the vfio_fsl_mc driver as
well.

Currently, when a child container is scanned by the vfio_fsl_mc driver,
child devices found are automatically bound to corresponding host kernel
drivers (e.g., DPMCP and DPBP objects are bound to the fsl_mc_allocator
driver, DPNI objects are bound to the ldpaa_eth driver, etc), Then,
the user has to manually unbind these child devices from their drivers,
set the driver_override sysfs attribute to vfio_fsl_mc driver, for each
of them and rebind them.

Signed-off-by: J. German Rivera <German.Rivera@freescale.com>
Reviewed-by: Stuart Yoder <stuart.yoder@freescale.com>
Tested-by: Stuart Yoder <stuart.yoder@freescale.com>
---
 drivers/staging/fsl-mc/bus/dprc-driver.c    | 14 ++++++++++----
 drivers/staging/fsl-mc/bus/mc-bus.c         | 16 +++++++++++++++-
 drivers/staging/fsl-mc/include/mc-private.h |  2 ++
 3 files changed, 27 insertions(+), 5 deletions(-)

diff --git a/drivers/staging/fsl-mc/bus/dprc-driver.c b/drivers/staging/fsl-mc/bus/dprc-driver.c
index 5351170..85ec91b 100644
--- a/drivers/staging/fsl-mc/bus/dprc-driver.c
+++ b/drivers/staging/fsl-mc/bus/dprc-driver.c
@@ -151,6 +151,8 @@ static void check_plugged_state_change(struct fsl_mc_device *mc_dev,
  * dprc_add_new_devices - Adds devices to the logical bus for a DPRC
  *
  * @mc_bus_dev: pointer to the fsl-mc device that represents a DPRC object
+ * @driver_override: driver override to apply to new objects found in the DPRC,
+ * or NULL, if none.
  * @obj_desc_array: array of device descriptors for child devices currently
  * present in the physical DPRC.
  * @num_child_objects_in_mc: number of entries in obj_desc_array
@@ -160,6 +162,7 @@ static void check_plugged_state_change(struct fsl_mc_device *mc_dev,
  * in the physical DPRC.
  */
 static void dprc_add_new_devices(struct fsl_mc_device *mc_bus_dev,
+				 const char *driver_override,
 				 struct dprc_obj_desc *obj_desc_array,
 				 int num_child_objects_in_mc)
 {
@@ -183,7 +186,7 @@ static void dprc_add_new_devices(struct fsl_mc_device *mc_bus_dev,
 		}

 		error = fsl_mc_device_add(obj_desc, NULL, &mc_bus_dev->dev,
-					  &child_dev);
+					  driver_override, &child_dev);
 		if (error < 0)
 			continue;
 	}
@@ -211,6 +214,8 @@ static void dprc_init_all_resource_pools(struct fsl_mc_device *mc_bus_dev)
  * dprc_scan_objects - Discover objects in a DPRC
  *
  * @mc_bus_dev: pointer to the fsl-mc device that represents a DPRC object
+ * @driver_override: driver override to apply to new objects found in the DPRC,
+ * or NULL, if none.
  * @total_irq_count: total number of IRQs needed by objects in the DPRC.
  *
  * Detects objects added and removed from a DPRC and synchronizes the
@@ -226,6 +231,7 @@ static void dprc_init_all_resource_pools(struct fsl_mc_device *mc_bus_dev)
  * of the device drivers for the non-allocatable devices.
  */
 int dprc_scan_objects(struct fsl_mc_device *mc_bus_dev,
+		      const char *driver_override,
 		      unsigned int *total_irq_count)
 {
 	int num_child_objects;
@@ -295,7 +301,7 @@ int dprc_scan_objects(struct fsl_mc_device *mc_bus_dev,
 	dprc_remove_devices(mc_bus_dev, child_obj_desc_array,
 			    num_child_objects);

-	dprc_add_new_devices(mc_bus_dev, child_obj_desc_array,
+	dprc_add_new_devices(mc_bus_dev, driver_override, child_obj_desc_array,
 			     num_child_objects);

 	kfree(child_obj_desc_array);
@@ -324,7 +330,7 @@ static int dprc_scan_container(struct fsl_mc_device *mc_bus_dev)
 	 * Discover objects in the DPRC:
 	 */
 	mutex_lock(&mc_bus->scan_mutex);
-	error = dprc_scan_objects(mc_bus_dev, &irq_count);
+	error = dprc_scan_objects(mc_bus_dev, NULL, &irq_count);
 	mutex_unlock(&mc_bus->scan_mutex);
 	if (error < 0)
 		return error;
@@ -397,7 +403,7 @@ static irqreturn_t dprc_irq0_handler_thread(int irq_num, void *arg)
 		      DPRC_IRQ_EVENT_OBJ_CREATED)) {
 		unsigned int irq_count;

-		error = dprc_scan_objects(mc_dev, &irq_count);
+		error = dprc_scan_objects(mc_dev, NULL, &irq_count);
 		if (error < 0) {
 			dev_err(dev, "dprc_scan_objects() failed: %d\n", error);
 			goto out;
diff --git a/drivers/staging/fsl-mc/bus/mc-bus.c b/drivers/staging/fsl-mc/bus/mc-bus.c
index fdd3d17..60e45be 100644
--- a/drivers/staging/fsl-mc/bus/mc-bus.c
+++ b/drivers/staging/fsl-mc/bus/mc-bus.c
@@ -401,6 +401,7 @@ error_cleanup_regions:
 int fsl_mc_device_add(struct dprc_obj_desc *obj_desc,
 		      struct fsl_mc_io *mc_io,
 		      struct device *parent_dev,
+		      const char *driver_override,
 		      struct fsl_mc_device **new_mc_dev)
 {
 	int error;
@@ -433,6 +434,18 @@ int fsl_mc_device_add(struct dprc_obj_desc *obj_desc,

 	mc_dev->obj_desc = *obj_desc;
 	mc_dev->mc_io = mc_io;
+	if (driver_override) {
+		/*
+		 * We trust driver_override, so we don't need to use
+		 * kstrndup() here
+		 */
+		mc_dev->driver_override = kstrdup(driver_override, GFP_KERNEL);
+		if (!mc_dev->driver_override) {
+			error = -ENOMEM;
+			goto error_cleanup_dev;
+		}
+	}
+
 	device_initialize(&mc_dev->dev);
 	mc_dev->dev.parent = parent_dev;
 	mc_dev->dev.bus = &fsl_mc_bus_type;
@@ -870,7 +883,8 @@ static int fsl_mc_bus_probe(struct platform_device *pdev)
 	obj_desc.irq_count = 1;
 	obj_desc.region_count = 0;

-	error = fsl_mc_device_add(&obj_desc, mc_io, &pdev->dev, &mc_bus_dev);
+	error = fsl_mc_device_add(&obj_desc, mc_io, &pdev->dev, NULL,
+				  &mc_bus_dev);
 	if (error < 0)
 		goto error_cleanup_mc_io;

diff --git a/drivers/staging/fsl-mc/include/mc-private.h b/drivers/staging/fsl-mc/include/mc-private.h
index 6e33942..5b9c8f2 100644
--- a/drivers/staging/fsl-mc/include/mc-private.h
+++ b/drivers/staging/fsl-mc/include/mc-private.h
@@ -106,11 +106,13 @@ struct fsl_mc_bus {
 int __must_check fsl_mc_device_add(struct dprc_obj_desc *obj_desc,
 				   struct fsl_mc_io *mc_io,
 				   struct device *parent_dev,
+				   const char *driver_override,
 				   struct fsl_mc_device **new_mc_dev);

 void fsl_mc_device_remove(struct fsl_mc_device *mc_dev);

 int dprc_scan_objects(struct fsl_mc_device *mc_bus_dev,
+		      const char *driver_override,
 		      unsigned int *total_irq_count);

 int __init dprc_driver_init(void);
--
2.3.3