Merge tag 'driver-core-5.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

Pull driver core updates from Greg Kroah-Hartman:
 "Here is the big driver core update for 5.4-rc1.

  There was a bit of a churn in here, with a number of core and OF
  platform patches being added to the tree, and then after much
  discussion and review and a day-long in-person meeting, they were
  decided to be reverted and a new set of patches is currently being
  reviewed on the mailing list.

  Other than that churn, there are two "persistent" branches in here
  that other trees will be pulling in as well during the merge window.
  One branch to add support for drivers to have the driver core
  automatically add sysfs attribute files when a driver is bound to a
  device so that the driver doesn't have to manually do it (and then
  clean it up, as it always gets it wrong).

  There's another branch in here for generic lookup helpers for the
  driver core that lots of busses are starting to use. That's the
  majority of the non-driver-core changes in this patch series.

  There's also some on-going debugfs file creation cleanup that has been
  slowly happening over the past few releases, with the goal to
  hopefully get that done sometime next year.

  All of these have been in linux-next for a while now with no reported
  issues"

[ Note that the above-mentioned generic lookup helpers branch was
  already brought in by the LED merge (commit 4feaab05dc1e) that had
  shared it.

  Also note that that common branch introduced an i2c bug due to a bad
  conversion, which got fixed here. - Linus ]

* tag 'driver-core-5.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (49 commits)
  coccinelle: platform_get_irq: Fix parse error
  driver-core: add include guard to linux/container.h
  sysfs: add BIN_ATTR_WO() macro
  driver core: platform: Export platform_get_irq_optional()
  hwmon: pwm-fan: Use platform_get_irq_optional()
  driver core: platform: Introduce platform_get_irq_optional()
  Revert "driver core: Add support for linking devices during device addition"
  Revert "driver core: Add edit_links() callback for drivers"
  Revert "of/platform: Add functional dependency link from DT bindings"
  Revert "driver core: Add sync_state driver/bus callback"
  Revert "of/platform: Pause/resume sync state during init and of_platform_populate()"
  Revert "of/platform: Create device links for all child-supplier depencencies"
  Revert "of/platform: Don't create device links for default busses"
  Revert "of/platform: Fix fn definitons for of_link_is_valid() and of_link_property()"
  Revert "of/platform: Fix device_links_supplier_sync_state_resume() warning"
  Revert "of/platform: Disable generic device linking code for PowerPC"
  devcoredump: fix typo in comment
  devcoredump: use memory_read_from_buffer
  of/platform: Disable generic device linking code for PowerPC
  device.h: Fix warnings for mismatched parameter names in comments
  ...

1 files changed, 102 insertions, 78 deletions

diff --git a/drivers/base/core.c b/drivers/base/core.c
index 832d4eae501e..2db62d98e395 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -136,6 +136,50 @@ static int device_is_dependent(struct device *dev, void *target)
 	return ret;
 }
 
+static void device_link_init_status(struct device_link *link,
+				    struct device *consumer,
+				    struct device *supplier)
+{
+	switch (supplier->links.status) {
+	case DL_DEV_PROBING:
+		switch (consumer->links.status) {
+		case DL_DEV_PROBING:
+			/*
+			 * A consumer driver can create a link to a supplier
+			 * that has not completed its probing yet as long as it
+			 * knows that the supplier is already functional (for
+			 * example, it has just acquired some resources from the
+			 * supplier).
+			 */
+			link->status = DL_STATE_CONSUMER_PROBE;
+			break;
+		default:
+			link->status = DL_STATE_DORMANT;
+			break;
+		}
+		break;
+	case DL_DEV_DRIVER_BOUND:
+		switch (consumer->links.status) {
+		case DL_DEV_PROBING:
+			link->status = DL_STATE_CONSUMER_PROBE;
+			break;
+		case DL_DEV_DRIVER_BOUND:
+			link->status = DL_STATE_ACTIVE;
+			break;
+		default:
+			link->status = DL_STATE_AVAILABLE;
+			break;
+		}
+		break;
+	case DL_DEV_UNBINDING:
+		link->status = DL_STATE_SUPPLIER_UNBIND;
+		break;
+	default:
+		link->status = DL_STATE_DORMANT;
+		break;
+	}
+}
+
 static int device_reorder_to_tail(struct device *dev, void *not_used)
 {
 	struct device_link *link;
@@ -177,6 +221,13 @@ void device_pm_move_to_tail(struct device *dev)
 	device_links_read_unlock(idx);
 }
 
+#define DL_MANAGED_LINK_FLAGS (DL_FLAG_AUTOREMOVE_CONSUMER | \
+			       DL_FLAG_AUTOREMOVE_SUPPLIER | \
+			       DL_FLAG_AUTOPROBE_CONSUMER)
+
+#define DL_ADD_VALID_FLAGS (DL_MANAGED_LINK_FLAGS | DL_FLAG_STATELESS | \
+			    DL_FLAG_PM_RUNTIME | DL_FLAG_RPM_ACTIVE)
+
 /**
  * device_link_add - Create a link between two devices.
  * @consumer: Consumer end of the link.
@@ -191,9 +242,9 @@ void device_pm_move_to_tail(struct device *dev)
  * of the link.  If DL_FLAG_PM_RUNTIME is not set, DL_FLAG_RPM_ACTIVE will be
  * ignored.
  *
- * If DL_FLAG_STATELESS is set in @flags, the link is not going to be managed by
- * the driver core and, in particular, the caller of this function is expected
- * to drop the reference to the link acquired by it directly.
+ * If DL_FLAG_STATELESS is set in @flags, the caller of this function is
+ * expected to release the link returned by it directly with the help of either
+ * device_link_del() or device_link_remove().
  *
  * If that flag is not set, however, the caller of this function is handing the
  * management of the link over to the driver core entirely and its return value
@@ -213,9 +264,16 @@ void device_pm_move_to_tail(struct device *dev)
  * be used to request the driver core to automaticall probe for a consmer
  * driver after successfully binding a driver to the supplier device.
  *
- * The combination of DL_FLAG_STATELESS and either DL_FLAG_AUTOREMOVE_CONSUMER
- * or DL_FLAG_AUTOREMOVE_SUPPLIER set in @flags at the same time is invalid and
- * will cause NULL to be returned upfront.
+ * The combination of DL_FLAG_STATELESS and one of DL_FLAG_AUTOREMOVE_CONSUMER,
+ * DL_FLAG_AUTOREMOVE_SUPPLIER, or DL_FLAG_AUTOPROBE_CONSUMER set in @flags at
+ * the same time is invalid and will cause NULL to be returned upfront.
+ * However, if a device link between the given @consumer and @supplier pair
+ * exists already when this function is called for them, the existing link will
+ * be returned regardless of its current type and status (the link's flags may
+ * be modified then).  The caller of this function is then expected to treat
+ * the link as though it has just been created, so (in particular) if
+ * DL_FLAG_STATELESS was passed in @flags, the link needs to be released
+ * explicitly when not needed any more (as stated above).
  *
  * A side effect of the link creation is re-ordering of dpm_list and the
  * devices_kset list by moving the consumer device and all devices depending
@@ -231,11 +289,8 @@ struct device_link *device_link_add(struct device *consumer,
 {
 	struct device_link *link;
 
-	if (!consumer || !supplier ||
-	    (flags & DL_FLAG_STATELESS &&
-	     flags & (DL_FLAG_AUTOREMOVE_CONSUMER |
-		      DL_FLAG_AUTOREMOVE_SUPPLIER |
-		      DL_FLAG_AUTOPROBE_CONSUMER)) ||
+	if (!consumer || !supplier || flags & ~DL_ADD_VALID_FLAGS ||
+	    (flags & DL_FLAG_STATELESS && flags & DL_MANAGED_LINK_FLAGS) ||
 	    (flags & DL_FLAG_AUTOPROBE_CONSUMER &&
 	     flags & (DL_FLAG_AUTOREMOVE_CONSUMER |
 		      DL_FLAG_AUTOREMOVE_SUPPLIER)))
@@ -248,6 +303,9 @@ struct device_link *device_link_add(struct device *consumer,
 		}
 	}
 
+	if (!(flags & DL_FLAG_STATELESS))
+		flags |= DL_FLAG_MANAGED;
+
 	device_links_write_lock();
 	device_pm_lock();
 
@@ -274,15 +332,6 @@ struct device_link *device_link_add(struct device *consumer,
 		if (link->consumer != consumer)
 			continue;
 
-		/*
-		 * Don't return a stateless link if the caller wants a stateful
-		 * one and vice versa.
-		 */
-		if (WARN_ON((flags & DL_FLAG_STATELESS) != (link->flags & DL_FLAG_STATELESS))) {
-			link = NULL;
-			goto out;
-		}
-
 		if (flags & DL_FLAG_PM_RUNTIME) {
 			if (!(link->flags & DL_FLAG_PM_RUNTIME)) {
 				pm_runtime_new_link(consumer);
@@ -293,6 +342,7 @@ struct device_link *device_link_add(struct device *consumer,
 		}
 
 		if (flags & DL_FLAG_STATELESS) {
+			link->flags |= DL_FLAG_STATELESS;
 			kref_get(&link->kref);
 			goto out;
 		}
@@ -311,6 +361,11 @@ struct device_link *device_link_add(struct device *consumer,
 			link->flags &= ~(DL_FLAG_AUTOREMOVE_CONSUMER |
 					 DL_FLAG_AUTOREMOVE_SUPPLIER);
 		}
+		if (!(link->flags & DL_FLAG_MANAGED)) {
+			kref_get(&link->kref);
+			link->flags |= DL_FLAG_MANAGED;
+			device_link_init_status(link, consumer, supplier);
+		}
 		goto out;
 	}
 
@@ -337,48 +392,10 @@ struct device_link *device_link_add(struct device *consumer,
 	kref_init(&link->kref);
 
 	/* Determine the initial link state. */
-	if (flags & DL_FLAG_STATELESS) {
+	if (flags & DL_FLAG_STATELESS)
 		link->status = DL_STATE_NONE;
-	} else {
-		switch (supplier->links.status) {
-		case DL_DEV_PROBING:
-			switch (consumer->links.status) {
-			case DL_DEV_PROBING:
-				/*
-				 * A consumer driver can create a link to a
-				 * supplier that has not completed its probing
-				 * yet as long as it knows that the supplier is
-				 * already functional (for example, it has just
-				 * acquired some resources from the supplier).
-				 */
-				link->status = DL_STATE_CONSUMER_PROBE;
-				break;
-			default:
-				link->status = DL_STATE_DORMANT;
-				break;
-			}
-			break;
-		case DL_DEV_DRIVER_BOUND:
-			switch (consumer->links.status) {
-			case DL_DEV_PROBING:
-				link->status = DL_STATE_CONSUMER_PROBE;
-				break;
-			case DL_DEV_DRIVER_BOUND:
-				link->status = DL_STATE_ACTIVE;
-				break;
-			default:
-				link->status = DL_STATE_AVAILABLE;
-				break;
-			}
-			break;
-		case DL_DEV_UNBINDING:
-			link->status = DL_STATE_SUPPLIER_UNBIND;
-			break;
-		default:
-			link->status = DL_STATE_DORMANT;
-			break;
-		}
-	}
+	else
+		device_link_init_status(link, consumer, supplier);
 
 	/*
 	 * Some callers expect the link creation during consumer driver probe to
@@ -540,7 +557,7 @@ static void device_links_missing_supplier(struct device *dev)
  * mark the link as "consumer probe in progress" to make the supplier removal
  * wait for us to complete (or bad things may happen).
  *
- * Links with the DL_FLAG_STATELESS flag set are ignored.
+ * Links without the DL_FLAG_MANAGED flag set are ignored.
  */
 int device_links_check_suppliers(struct device *dev)
 {
@@ -550,7 +567,7 @@ int device_links_check_suppliers(struct device *dev)
 	device_links_write_lock();
 
 	list_for_each_entry(link, &dev->links.suppliers, c_node) {
-		if (link->flags & DL_FLAG_STATELESS)
+		if (!(link->flags & DL_FLAG_MANAGED))
 			continue;
 
 		if (link->status != DL_STATE_AVAILABLE) {
@@ -575,7 +592,7 @@ int device_links_check_suppliers(struct device *dev)
  *
  * Also change the status of @dev's links to suppliers to "active".
  *
- * Links with the DL_FLAG_STATELESS flag set are ignored.
+ * Links without the DL_FLAG_MANAGED flag set are ignored.
  */
 void device_links_driver_bound(struct device *dev)
 {
@@ -584,7 +601,7 @@ void device_links_driver_bound(struct device *dev)
 	device_links_write_lock();
 
 	list_for_each_entry(link, &dev->links.consumers, s_node) {
-		if (link->flags & DL_FLAG_STATELESS)
+		if (!(link->flags & DL_FLAG_MANAGED))
 			continue;
 
 		/*
@@ -605,7 +622,7 @@ void device_links_driver_bound(struct device *dev)
 	}
 
 	list_for_each_entry(link, &dev->links.suppliers, c_node) {
-		if (link->flags & DL_FLAG_STATELESS)
+		if (!(link->flags & DL_FLAG_MANAGED))
 			continue;
 
 		WARN_ON(link->status != DL_STATE_CONSUMER_PROBE);
@@ -617,6 +634,13 @@ void device_links_driver_bound(struct device *dev)
 	device_links_write_unlock();
 }
 
+static void device_link_drop_managed(struct device_link *link)
+{
+	link->flags &= ~DL_FLAG_MANAGED;
+	WRITE_ONCE(link->status, DL_STATE_NONE);
+	kref_put(&link->kref, __device_link_del);
+}
+
 /**
  * __device_links_no_driver - Update links of a device without a driver.
  * @dev: Device without a drvier.
@@ -627,18 +651,18 @@ void device_links_driver_bound(struct device *dev)
  * unless they already are in the "supplier unbind in progress" state in which
  * case they need not be updated.
  *
- * Links with the DL_FLAG_STATELESS flag set are ignored.
+ * Links without the DL_FLAG_MANAGED flag set are ignored.
  */
 static void __device_links_no_driver(struct device *dev)
 {
 	struct device_link *link, *ln;
 
 	list_for_each_entry_safe_reverse(link, ln, &dev->links.suppliers, c_node) {
-		if (link->flags & DL_FLAG_STATELESS)
+		if (!(link->flags & DL_FLAG_MANAGED))
 			continue;
 
 		if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER)
-			__device_link_del(&link->kref);
+			device_link_drop_managed(link);
 		else if (link->status == DL_STATE_CONSUMER_PROBE ||
 			 link->status == DL_STATE_ACTIVE)
 			WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
@@ -655,7 +679,7 @@ static void __device_links_no_driver(struct device *dev)
  * %__device_links_no_driver() to update links to suppliers for it as
  * appropriate.
  *
- * Links with the DL_FLAG_STATELESS flag set are ignored.
+ * Links without the DL_FLAG_MANAGED flag set are ignored.
  */
 void device_links_no_driver(struct device *dev)
 {
@@ -664,7 +688,7 @@ void device_links_no_driver(struct device *dev)
 	device_links_write_lock();
 
 	list_for_each_entry(link, &dev->links.consumers, s_node) {
-		if (link->flags & DL_FLAG_STATELESS)
+		if (!(link->flags & DL_FLAG_MANAGED))
 			continue;
 
 		/*
@@ -692,7 +716,7 @@ void device_links_no_driver(struct device *dev)
  * invoke %__device_links_no_driver() to update links to suppliers for it as
  * appropriate.
  *
- * Links with the DL_FLAG_STATELESS flag set are ignored.
+ * Links without the DL_FLAG_MANAGED flag set are ignored.
  */
 void device_links_driver_cleanup(struct device *dev)
 {
@@ -701,7 +725,7 @@ void device_links_driver_cleanup(struct device *dev)
 	device_links_write_lock();
 
 	list_for_each_entry_safe(link, ln, &dev->links.consumers, s_node) {
-		if (link->flags & DL_FLAG_STATELESS)
+		if (!(link->flags & DL_FLAG_MANAGED))
 			continue;
 
 		WARN_ON(link->flags & DL_FLAG_AUTOREMOVE_CONSUMER);
@@ -714,7 +738,7 @@ void device_links_driver_cleanup(struct device *dev)
 		 */
 		if (link->status == DL_STATE_SUPPLIER_UNBIND &&
 		    link->flags & DL_FLAG_AUTOREMOVE_SUPPLIER)
-			__device_link_del(&link->kref);
+			device_link_drop_managed(link);
 
 		WRITE_ONCE(link->status, DL_STATE_DORMANT);
 	}
@@ -736,7 +760,7 @@ void device_links_driver_cleanup(struct device *dev)
  *
  * Return 'false' if there are no probing or active consumers.
  *
- * Links with the DL_FLAG_STATELESS flag set are ignored.
+ * Links without the DL_FLAG_MANAGED flag set are ignored.
  */
 bool device_links_busy(struct device *dev)
 {
@@ -746,7 +770,7 @@ bool device_links_busy(struct device *dev)
 	device_links_write_lock();
 
 	list_for_each_entry(link, &dev->links.consumers, s_node) {
-		if (link->flags & DL_FLAG_STATELESS)
+		if (!(link->flags & DL_FLAG_MANAGED))
 			continue;
 
 		if (link->status == DL_STATE_CONSUMER_PROBE
@@ -776,7 +800,7 @@ bool device_links_busy(struct device *dev)
  * driver to unbind and start over (the consumer will not re-probe as we have
  * changed the state of the link already).
  *
- * Links with the DL_FLAG_STATELESS flag set are ignored.
+ * Links without the DL_FLAG_MANAGED flag set are ignored.
  */
 void device_links_unbind_consumers(struct device *dev)
 {
@@ -788,7 +812,7 @@ void device_links_unbind_consumers(struct device *dev)
 	list_for_each_entry(link, &dev->links.consumers, s_node) {
 		enum device_link_state status;
 
-		if (link->flags & DL_FLAG_STATELESS)
+		if (!(link->flags & DL_FLAG_MANAGED))
 			continue;
 
 		status = link->status;