[PATCH v14 3/5] rpmsg: core: match rpmsg device IDs by prefix

[Shenwei Wang]

From: Shenwei Wang <shenwei.wang@xxxxxxx>

The current rpmsg_id_match() implementation requires an exact
string match between the driver id_table entry and the rpmsg
device name using strncmp() with RPMSG_NAME_SIZE.

This makes it impossible for a driver to match a group of
rpmsg devices sharing a common prefix (e.g. dynamically
suffixed channel names).

Update the matching logic to compare only the length of the
id->name string, allowing id_table entries to act as prefixes.
This enables drivers to bind to devices whose names start with
the specified id->name.

The implementation is copied from a reply by Mathieu.

Signed-off-by: Shenwei Wang <shenwei.wang@xxxxxxx>
---
 drivers/rpmsg/rpmsg_core.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/rpmsg/rpmsg_core.c b/drivers/rpmsg/rpmsg_core.c
index e7f7831d37f8..f95bfc9965d4 100644
--- a/drivers/rpmsg/rpmsg_core.c
+++ b/drivers/rpmsg/rpmsg_core.c
@@ -414,7 +414,9 @@ ATTRIBUTE_GROUPS(rpmsg_dev);
 static inline int rpmsg_id_match(const struct rpmsg_device *rpdev,
 				  const struct rpmsg_device_id *id)
 {
-	return strncmp(id->name, rpdev->id.name, RPMSG_NAME_SIZE) == 0;
+	size_t len = strnlen(id->name, RPMSG_NAME_SIZE);
+
+	return strncmp(id->name, rpdev->id.name, len) == 0;
 }
 
 /* match rpmsg channel and rpmsg driver */
-- 
2.43.0