linux-kernel - [PATCH v3 2/3] interconnect: Reintroduce icc

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Date:   Mon, 7 Aug 2023 07:29:13 -0700
From:   Mike Tipton <quic_mdtipton@...cinc.com>
To:     <djakov@...nel.org>, <gregkh@...uxfoundation.org>,
        <rafael@...nel.org>, <corbet@....net>
CC:     <linux-pm@...r.kernel.org>, <linux-doc@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <linux-arm-msm@...r.kernel.org>,
        <quic_okukatla@...cinc.com>, <quic_viveka@...cinc.com>,
        <peterz@...radead.org>, <quic_pkondeti@...cinc.com>,
        Mike Tipton <quic_mdtipton@...cinc.com>
Subject: [PATCH v3 2/3] interconnect: Reintroduce icc_get()

The original icc_get() that took integer node IDs was removed due to
lack of users. Reintroduce a new version that takes string node names,
which is needed for the debugfs client.

Signed-off-by: Mike Tipton <quic_mdtipton@...cinc.com>
---
 drivers/interconnect/core.c     | 63 +++++++++++++++++++++++++++++++++
 drivers/interconnect/internal.h |  2 ++
 2 files changed, 65 insertions(+)

diff --git a/drivers/interconnect/core.c b/drivers/interconnect/core.c
index 5fac448c28fd..fc1461dfc61b 100644
--- a/drivers/interconnect/core.c
+++ b/drivers/interconnect/core.c
@@ -147,6 +147,21 @@ static struct icc_node *node_find(const int id)
 	return idr_find(&icc_idr, id);
 }
 
+static struct icc_node *node_find_by_name(const char *name)
+{
+	struct icc_provider *provider;
+	struct icc_node *n;
+
+	list_for_each_entry(provider, &icc_providers, provider_list) {
+		list_for_each_entry(n, &provider->nodes, node_list) {
+			if (!strcmp(n->name, name))
+				return n;
+		}
+	}
+
+	return NULL;
+}
+
 static struct icc_path *path_init(struct device *dev, struct icc_node *dst,
 				  ssize_t num_nodes)
 {
@@ -561,6 +576,54 @@ struct icc_path *of_icc_get(struct device *dev, const char *name)
 }
 EXPORT_SYMBOL_GPL(of_icc_get);
 
+/**
+ * icc_get() - get a path handle between two endpoints
+ * @dev: device pointer for the consumer device
+ * @src: source node name
+ * @dst: destination node name
+ *
+ * This function will search for a path between two endpoints and return an
+ * icc_path handle on success. Use icc_put() to release constraints when they
+ * are not needed anymore.
+ *
+ * Return: icc_path pointer on success or ERR_PTR() on error. NULL is returned
+ * when the API is disabled.
+ */
+struct icc_path *icc_get(struct device *dev, const char *src, const char *dst)
+{
+	struct icc_node *src_node, *dst_node;
+	struct icc_path *path = ERR_PTR(-EPROBE_DEFER);
+
+	mutex_lock(&icc_lock);
+
+	src_node = node_find_by_name(src);
+	if (!src_node) {
+		dev_err(dev, "%s: invalid src=%s\n", __func__, src);
+		goto out;
+	}
+
+	dst_node = node_find_by_name(dst);
+	if (!dst_node) {
+		dev_err(dev, "%s: invalid dst=%s\n", __func__, dst);
+		goto out;
+	}
+
+	path = path_find(dev, src_node, dst_node);
+	if (IS_ERR(path)) {
+		dev_err(dev, "%s: invalid path=%ld\n", __func__, PTR_ERR(path));
+		goto out;
+	}
+
+	path->name = kasprintf(GFP_KERNEL, "%s-%s", src_node->name, dst_node->name);
+	if (!path->name) {
+		kfree(path);
+		path = ERR_PTR(-ENOMEM);
+	}
+out:
+	mutex_unlock(&icc_lock);
+	return path;
+}
+
 /**
  * icc_set_tag() - set an optional tag on a path
  * @path: the path we want to tag
diff --git a/drivers/interconnect/internal.h b/drivers/interconnect/internal.h
index f5f82a5c939e..95d6ba27bf78 100644
--- a/drivers/interconnect/internal.h
+++ b/drivers/interconnect/internal.h
@@ -41,4 +41,6 @@ struct icc_path {
 	struct icc_req reqs[];
 };
 
+struct icc_path *icc_get(struct device *dev, const char *src, const char *dst);
+
 #endif
-- 
2.17.1