[PATCH 1/2] clk: scmi: register all scmi clock by name with CCF

[Etienne Carriere]

From: Patrick Delaunay <patrick.delaunay at st.com>

This patch implements SCMI APIs to retrieve the number and the name of
SCMI clocks using SCMI_PROTOCOL_ATTRIBUTES messages.

Signed-off-by: Gabriel Fernandez <gabriel.fernandez at st.com>
Signed-off-by: Patrick Delaunay <patrick.delaunay at st.com>
Signed-off-by: Etienne Carriere <etienne.carriere at linaro.org>
---
 drivers/clk/clk_scmi.c   | 101 +++++++++++++++++++++++++++++++++++++++
 include/scmi_protocols.h |  43 +++++++++++++++++
 2 files changed, 144 insertions(+)

diff --git a/drivers/clk/clk_scmi.c b/drivers/clk/clk_scmi.c
index 93a4819501..2a4c10a427 100644
--- a/drivers/clk/clk_scmi.c
+++ b/drivers/clk/clk_scmi.c
@@ -8,6 +8,50 @@
 #include <scmi_agent.h>
 #include <scmi_protocols.h>
 #include <asm/types.h>
+#include <linux/clk-provider.h>
+
+static u16 scmi_clk_get_num_clock(struct udevice *dev)
+{
+	struct scmi_clk_protocol_attr_out out;
+	struct scmi_msg msg = {
+		.protocol_id = SCMI_PROTOCOL_ID_CLOCK,
+		.message_id = SCMI_PROTOCOL_ATTRIBUTES,
+		.out_msg = (u8 *)&out,
+		.out_msg_sz = sizeof(out),
+	};
+	int ret;
+
+	ret = devm_scmi_process_msg(dev->parent, &msg);
+	if (ret)
+		return ret;
+
+	return out.attributes & SCMI_CLK_PROTO_ATTR_COUNT_MASK;
+}
+
+static int scmi_clk_get_attibute(struct udevice *dev, int clkid, char **name)
+{
+	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->parent, &msg);
+	if (ret)
+		return ret;
+
+	*name = out.clock_name;
+
+	return 0;
+}
 
 static int scmi_clk_gate(struct clk *clk, int enable)
 {
@@ -85,6 +129,62 @@ static ulong scmi_clk_set_rate(struct clk *clk, ulong rate)
 	return scmi_clk_get_rate(clk);
 }
 
+static struct clk *scmi_clk_register(struct udevice *dev, const char *name)
+{
+	struct clk *clk;
+	int ret;
+
+	clk = kzalloc(sizeof(*clk), GFP_KERNEL);
+	if (!clk)
+		return ERR_PTR(-ENOMEM);
+
+	ret = clk_register(clk, dev->driver->name, name, dev->name);
+	if (ret) {
+		kfree(clk);
+		return ERR_PTR(ret);
+	}
+
+	return clk;
+}
+
+static int scmi_clk_probe(struct udevice *dev)
+{
+	struct clk *clk;
+	int num_clocks;
+	int i;
+
+	if (!CONFIG_IS_ENABLED(CLK_CCF))
+		return 0;
+
+	/* register CCF children: CLK UCLASS, no probed again */
+	if (device_get_uclass_id(dev->parent) == UCLASS_CLK)
+		return 0;
+
+	num_clocks = scmi_clk_get_num_clock(dev);
+	if (!num_clocks)
+		return 0;
+
+	for (i = 0; i < num_clocks; i++) {
+		char *name;
+
+		if (!scmi_clk_get_attibute(dev, i, &name)) {
+			char *clock_name = strdup(name);
+
+			clk = scmi_clk_register(dev, clock_name);
+			if (!IS_ERR(clk)) {
+				clk->id = i;
+				clk_request(dev, clk);
+			} else {
+				free(clock_name);
+
+				return PTR_ERR(clk);
+			}
+		}
+	}
+
+	return 0;
+}
+
 static const struct clk_ops scmi_clk_ops = {
 	.enable = scmi_clk_enable,
 	.disable = scmi_clk_disable,
@@ -96,4 +196,5 @@ U_BOOT_DRIVER(scmi_clock) = {
 	.name = "scmi_clk",
 	.id = UCLASS_CLK,
 	.ops = &scmi_clk_ops,
+	.probe = &scmi_clk_probe,
 };
diff --git a/include/scmi_protocols.h b/include/scmi_protocols.h
index 2db71697e8..3fc8ec95ef 100644
--- a/include/scmi_protocols.h
+++ b/include/scmi_protocols.h
@@ -40,22 +40,65 @@ enum scmi_status_code {
 	SCMI_PROTOCOL_ERROR = -10,
 };
 
+/*
+ * Generic message IDs
+ */
+enum scmi_discovery_id {
+	SCMI_PROTOCOL_VERSION = 0x0,
+	SCMI_PROTOCOL_ATTRIBUTES = 0x1,
+	SCMI_PROTOCOL_MESSAGE_ATTRIBUTES = 0x2,
+};
+
 /*
  * SCMI Clock Protocol
  */
 
 enum scmi_clock_message_id {
+	SCMI_CLOCK_ATTRIBUTES = 0x3,
 	SCMI_CLOCK_RATE_SET = 0x5,
 	SCMI_CLOCK_RATE_GET = 0x6,
 	SCMI_CLOCK_CONFIG_SET = 0x7,
 };
 
+#define SCMI_CLK_PROTO_ATTR_COUNT_MASK	GENMASK(15, 0)
 #define SCMI_CLK_RATE_ASYNC_NOTIFY	BIT(0)
 #define SCMI_CLK_RATE_ASYNC_NORESP	(BIT(0) | BIT(1))
 #define SCMI_CLK_RATE_ROUND_DOWN	0
 #define SCMI_CLK_RATE_ROUND_UP		BIT(2)
 #define SCMI_CLK_RATE_ROUND_CLOSEST	BIT(3)
 
+#define SCMI_CLOCK_NAME_LENGTH_MAX 16
+
+/**
+ * struct scmi_clk_get_nb_out - Response for SCMI_PROTOCOL_ATTRIBUTES command
+ * @status:	SCMI command status
+ * @attributes:	Attributes of the clock protocol, mainly number of clocks exposed
+ */
+struct scmi_clk_protocol_attr_out {
+	s32 status;
+	u32 attributes;
+};
+
+/**
+ * struct scmi_clk_attribute_in - Message payload for SCMI_CLOCK_ATTRIBUTES command
+ * @clock_id:	SCMI clock ID
+ */
+struct scmi_clk_attribute_in {
+	u32 clock_id;
+};
+
+/**
+ * struct scmi_clk_get_nb_out - Response payload for SCMI_CLOCK_ATTRIBUTES command
+ * @status:	SCMI command status
+ * @attributes:	clock attributes
+ * @clock_name:	name of the clock
+ */
+struct scmi_clk_attribute_out {
+	s32 status;
+	u32 attributes;
+	char clock_name[SCMI_CLOCK_NAME_LENGTH_MAX];
+};
+
 /**
  * struct scmi_clk_state_in - Message payload for CLOCK_CONFIG_SET command
  * @clock_id:	SCMI clock ID
-- 
2.17.1