Commit 74c782cf authored by Saravana Kannan's avatar Saravana Kannan Committed by Greg Kroah-Hartman
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driver core: fw_devlink: Handle suppliers that don't use driver core 



Device links only work between devices that use the driver core to match
and bind a driver to a device. So, add an API for frameworks to let the
driver core know that a fwnode has been initialized by a driver without
using the driver core.

Then use this information to make sure that fw_devlink doesn't make the
consumers wait indefinitely on suppliers that'll never bind to a driver.

Tested-by: default avatarMarek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: default avatarSaravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20210205222644.2357303-6-saravanak@google.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent a9dd8f3c

drivers/base/core.c

+15 −0
Original line number Diff line number Diff line
@@ -1636,6 +1636,17 @@ static int fw_devlink_create_devlink(struct device *con, 


	sup_dev = get_dev_from_fwnode(sup_handle);

	if (sup_dev) {

		/*

		 * If it's one of those drivers that don't actually bind to

		 * their device using driver core, then don't wait on this

		 * supplier device indefinitely.

		 */

		if (sup_dev->links.status == DL_DEV_NO_DRIVER &&

		    sup_handle->flags & FWNODE_FLAG_INITIALIZED) {

			ret = -EINVAL;

			goto out;

		}



		/*

		 * If this fails, it is due to cycles in device links.  Just

		 * give up on this link and treat it as invalid.
@@ -1655,6 +1666,10 @@ static int fw_devlink_create_devlink(struct device *con, 
		goto out;

	}



	/* Supplier that's already initialized without a struct device. */

	if (sup_handle->flags & FWNODE_FLAG_INITIALIZED)

		return -EINVAL;



	/*

	 * DL_FLAG_SYNC_STATE_ONLY doesn't block probing and supports

	 * cycles. So cycle detection isn't necessary and shouldn't be

include/linux/fwnode.h

+17 −2
Original line number Diff line number Diff line
@@ -11,6 +11,7 @@ 


#include <linux/types.h>

#include <linux/list.h>

#include <linux/err.h>



struct fwnode_operations;

struct device;
@@ -20,9 +21,11 @@ struct device; 
 *

 * LINKS_ADDED:	The fwnode has already be parsed to add fwnode links.

 * NOT_DEVICE:	The fwnode will never be populated as a struct device.

 * INITIALIZED: The hardware corresponding to fwnode has been initialized.

 */

#define FWNODE_FLAG_LINKS_ADDED		BIT(0)

#define FWNODE_FLAG_NOT_DEVICE		BIT(1)

#define FWNODE_FLAG_INITIALIZED		BIT(2)



struct fwnode_handle {

	struct fwnode_handle *secondary;
@@ -161,6 +164,18 @@ static inline void fwnode_init(struct fwnode_handle *fwnode, 
	INIT_LIST_HEAD(&fwnode->suppliers);

}



static inline void fwnode_dev_initialized(struct fwnode_handle *fwnode,

					  bool initialized)

{

	if (IS_ERR_OR_NULL(fwnode))

		return;



	if (initialized)

		fwnode->flags |= FWNODE_FLAG_INITIALIZED;

	else

		fwnode->flags &= ~FWNODE_FLAG_INITIALIZED;

}



extern u32 fw_devlink_get_flags(void);

extern bool fw_devlink_is_strict(void);

int fwnode_link_add(struct fwnode_handle *con, struct fwnode_handle *sup);