[PATCH v9 1/4] firmware: arm_scmi: introduce helper get_max_msg_size

[Peng Fan (OSS)]

From: Peng Fan <peng.fan@xxxxxxx>

When Agent sending data to SCMI server, the Agent driver could check
the size to avoid protocol buffer overflow. So introduce the helper
get_max_msg_size.

Reviewed-by: Cristian Marussi <cristian.marussi@xxxxxxx>
Reviewed-by: Dhruva Gole <d-gole@xxxxxx>
Signed-off-by: Peng Fan <peng.fan@xxxxxxx>
---
 drivers/firmware/arm_scmi/driver.c    | 15 +++++++++++++++
 drivers/firmware/arm_scmi/protocols.h |  2 ++
 2 files changed, 17 insertions(+)

diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c
index 36e3eb50a8d4..a1e0e8fa4bb7 100644
--- a/drivers/firmware/arm_scmi/driver.c
+++ b/drivers/firmware/arm_scmi/driver.c
@@ -1537,6 +1537,20 @@ static int scmi_common_extended_name_get(const struct scmi_protocol_handle *ph,
 	return ret;
 }
 
+/**
+ * scmi_common_get_max_msg_size  - Get maximum message size
+ * @ph: A protocol handle reference.
+ *
+ * Return: Maximum message size for the current protocol.
+ */
+static int scmi_common_get_max_msg_size(const struct scmi_protocol_handle *ph)
+{
+	const struct scmi_protocol_instance *pi = ph_to_pi(ph);
+	struct scmi_info *info = handle_to_scmi_info(pi->handle);
+
+	return info->desc->max_msg_size;
+}
+
 /**
  * struct scmi_iterator  - Iterator descriptor
  * @msg: A reference to the message TX buffer; filled by @prepare_message with
@@ -1848,6 +1862,7 @@ static int scmi_protocol_msg_check(const struct scmi_protocol_handle *ph,
 
 static const struct scmi_proto_helpers_ops helpers_ops = {
 	.extended_name_get = scmi_common_extended_name_get,
+	.get_max_msg_size = scmi_common_get_max_msg_size,
 	.iter_response_init = scmi_iterator_init,
 	.iter_response_run = scmi_iterator_run,
 	.protocol_msg_check = scmi_protocol_msg_check,
diff --git a/drivers/firmware/arm_scmi/protocols.h b/drivers/firmware/arm_scmi/protocols.h
index 317d3fb32676..3e91536a77a3 100644
--- a/drivers/firmware/arm_scmi/protocols.h
+++ b/drivers/firmware/arm_scmi/protocols.h
@@ -258,6 +258,7 @@ struct scmi_fc_info {
  * @fastchannel_init: A common helper used to initialize FC descriptors by
  *		      gathering FC descriptions from the SCMI platform server.
  * @fastchannel_db_ring: A common helper to ring a FC doorbell.
+ * @get_max_msg_size: A common helper to get the maximum message size.
  */
 struct scmi_proto_helpers_ops {
 	int (*extended_name_get)(const struct scmi_protocol_handle *ph,
@@ -277,6 +278,7 @@ struct scmi_proto_helpers_ops {
 				 struct scmi_fc_db_info **p_db,
 				 u32 *rate_limit);
 	void (*fastchannel_db_ring)(struct scmi_fc_db_info *db);
+	int (*get_max_msg_size)(const struct scmi_protocol_handle *ph);
 };
 
 /**

-- 
2.37.1