[PATCH v1 01/13] clk: scmi: add compatibility with clock protocol 2.0

[Patrice Chotard]

From: Valentin Caron <valentin.caron at foss.st.com>

Since clock protocol 2.0, SCMI specification add an option field
"clock_enable_delay" to CLOCK_ATTRIBUTES command.

scmi_read_resp_from_smt() will return an error ("Buffer too small") as
the message length coming from the SCMI server is not the same as expected.

So implement a condition to SCMI clock protocol version to change the
length of the expected message.

Signed-off-by: Valentin Caron <valentin.caron at foss.st.com>
Signed-off-by: Patrice Chotard <patrice.chotard at foss.st.com>
Cc: Lukasz Majewski <lukma at denx.de>
Cc: Sean Anderson <seanga2 at gmail.com>
---

 drivers/clk/clk_scmi.c   | 54 +++++++++++++++++++++++++++++-----------
 include/scmi_protocols.h | 15 +++++++++++
 2 files changed, 54 insertions(+), 15 deletions(-)

diff --git a/drivers/clk/clk_scmi.c b/drivers/clk/clk_scmi.c
index af69850cdd8..e323a948780 100644
--- a/drivers/clk/clk_scmi.c
+++ b/drivers/clk/clk_scmi.c
@@ -84,26 +84,47 @@ static int scmi_clk_get_num_clock(struct udevice *dev, size_t *num_clocks)
 static int scmi_clk_get_attibute(struct udevice *dev, int clkid, char **name,
 				 u32 *attr)
 {
+	struct scmi_clock_priv *priv = dev_get_priv(dev);
 	struct scmi_clk_attribute_in in = {
 		.clock_id = clkid,
 	};
-	struct scmi_clk_attribute_out out;
-	struct scmi_msg msg = {
-		.protocol_id = SCMI_PROTOCOL_ID_CLOCK,
-		.message_id = SCMI_CLOCK_ATTRIBUTES,
-		.in_msg = (u8 *)&in,
-		.in_msg_sz = sizeof(in),
-		.out_msg = (u8 *)&out,
-		.out_msg_sz = sizeof(out),
-	};
 	int ret;
 
-	ret = devm_scmi_process_msg(dev, &msg);
-	if (ret)
-		return ret;
-
-	*name = strdup(out.clock_name);
-	*attr = out.attributes;
+	if (priv->version >= 0x20000) {
+		struct scmi_clk_attribute_out_v2 out;
+		struct scmi_msg msg = {
+			.protocol_id = SCMI_PROTOCOL_ID_CLOCK,
+			.message_id = SCMI_CLOCK_ATTRIBUTES,
+			.in_msg = (u8 *)&in,
+			.in_msg_sz = sizeof(in),
+			.out_msg = (u8 *)&out,
+			.out_msg_sz = sizeof(out),
+		};
+
+		ret = devm_scmi_process_msg(dev, &msg);
+		if (ret)
+			return ret;
+
+		*name = strdup(out.clock_name);
+		*attr = out.attributes;
+	} else {
+		struct scmi_clk_attribute_out out;
+		struct scmi_msg msg = {
+			.protocol_id = SCMI_PROTOCOL_ID_CLOCK,
+			.message_id = SCMI_CLOCK_ATTRIBUTES,
+			.in_msg = (u8 *)&in,
+			.in_msg_sz = sizeof(in),
+			.out_msg = (u8 *)&out,
+			.out_msg_sz = sizeof(out),
+		};
+
+		ret = devm_scmi_process_msg(dev, &msg);
+		if (ret)
+			return ret;
+
+		*name = strdup(out.clock_name);
+		*attr = out.attributes;
+	}
 
 	return 0;
 }
@@ -257,6 +278,9 @@ static int scmi_clk_probe(struct udevice *dev)
 	if (!CONFIG_IS_ENABLED(CLK_CCF))
 		return 0;
 
+	ret = scmi_generic_protocol_version(dev, SCMI_PROTOCOL_ID_CLOCK,
+					    &priv->version);
+
 	/* register CCF children: CLK UCLASS, no probed again */
 	if (device_get_uclass_id(dev->parent) == UCLASS_CLK)
 		return 0;
diff --git a/include/scmi_protocols.h b/include/scmi_protocols.h
index 9046de7e3e7..762a1032c37 100644
--- a/include/scmi_protocols.h
+++ b/include/scmi_protocols.h
@@ -782,6 +782,21 @@ struct scmi_clk_attribute_out {
 	char clock_name[SCMI_CLOCK_NAME_LENGTH_MAX];
 };
 
+/**
+ * struct scmi_clk_get_nb_out_v2 - Response payload for SCMI_CLOCK_ATTRIBUTES command
+ * Clock management Protocol 2.0
+ * @status:	SCMI command status
+ * @attributes:	clock attributes
+ * @clock_name:	name of the clock
+ * @clock_enable_delay: delay incurred by the platform to enable the clock
+ */
+struct scmi_clk_attribute_out_v2 {
+	s32 status;
+	u32 attributes;
+	char clock_name[SCMI_CLOCK_NAME_LENGTH_MAX];
+	u32 clock_enable_delay;
+};
+
 /**
  * struct scmi_clk_state_in - Message payload for CLOCK_CONFIG_SET command
  * @clock_id:	SCMI clock ID
-- 
2.25.1