[RFC PATCH v3 3/7] interconnect: Allow inter-provider pairs to be configured

[Artur Świgoń <a.swigon@xxxxxxxxxxx>]

In the exynos-bus devfreq driver every bus is probed separately and is
assigned a separate interconnect provider. However, the interconnect
framework does not call the '->set' callback for pairs of nodes which
belong to different providers.

This patch adds support for a new boolean 'inter_set' field in struct
icc_provider. Setting it to 'true' enables calling '->set' for
inter-provider node pairs. All existing users of the interconnect
framework allocate this structure with kzalloc, and are therefore
unaffected.

Signed-off-by: Artur Świgoń <a.swigon@xxxxxxxxxxx>
---
 drivers/interconnect/core.c           | 11 +++++------
 include/linux/interconnect-provider.h |  2 ++
 2 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/drivers/interconnect/core.c b/drivers/interconnect/core.c
index 74c68898a350..a28bd0f8a497 100644
--- a/drivers/interconnect/core.c
+++ b/drivers/interconnect/core.c
@@ -259,23 +259,22 @@ static int aggregate_requests(struct icc_node *node)
 static int apply_constraints(struct icc_path *path)
 {
 	struct icc_node *next, *prev = NULL;
+	struct icc_provider *p;
 	int ret = -EINVAL;
 	int i;
 
 	for (i = 0; i < path->num_nodes; i++) {
 		next = path->reqs[i].node;
+		p = next->provider;
 
-		/*
-		 * Both endpoints should be valid master-slave pairs of the
-		 * same interconnect provider that will be configured.
-		 */
-		if (!prev || next->provider != prev->provider) {
+		/* both endpoints should be valid master-slave pairs */
+		if (!prev || (p != prev->provider && !p->inter_set)) {
 			prev = next;
 			continue;
 		}
 
 		/* set the constraints */
-		ret = next->provider->set(prev, next);
+		ret = p->set(prev, next);
 		if (ret)
 			goto out;
 
diff --git a/include/linux/interconnect-provider.h b/include/linux/interconnect-provider.h
index cc965b8fab53..b6ae0ee686c5 100644
--- a/include/linux/interconnect-provider.h
+++ b/include/linux/interconnect-provider.h
@@ -41,6 +41,7 @@ struct icc_node *of_icc_xlate_onecell(struct of_phandle_args *spec,
  * @xlate: provider-specific callback for mapping nodes from phandle arguments
  * @dev: the device this interconnect provider belongs to
  * @users: count of active users
+ * @inter_set: whether inter-provider pairs will be configured with @set
  * @data: pointer to private data
  */
 struct icc_provider {
@@ -53,6 +54,7 @@ struct icc_provider {
 	struct icc_node* (*xlate)(struct of_phandle_args *spec, void *data);
 	struct device		*dev;
 	int			users;
+	bool			inter_set;
 	void			*data;
 };
 
-- 
2.17.1