clk: scmi: register scmi clocks with CCF

Implements SCMI APIs to retrieve the number exposed SCMI clocks using
SCMI_PROTOCOL_ATTRIBUTES messages and the names of the clocks using
SCMI_CLOCK_ATTRIBUTES messages.

This change updates sandbox SCMI clock test driver to manage these
2 new message IDs.

Cc: Lukasz Majewski <lukma@denx.de>
Cc: Sean Anderson <seanga2@gmail.com>
Cc: Clement Leger <clement.leger@bootlin.com>
Cc: Patrick Delaunay <patrick.delaunay@foss.st.com>
Reviewed-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
Signed-off-by: Gabriel Fernandez <gabriel.fernandez@st.com>
Signed-off-by: Etienne Carriere <etienne.carriere@linaro.org>

drivers/clk/clk_scmi.c

@@ -11,6 +11,52 @@
 #include <scmi_agent.h>
 #include <scmi_protocols.h>
 #include <asm/types.h>
+#include <linux/clk-provider.h>
+
+static int scmi_clk_get_num_clock(struct udevice *dev, size_t *num_clocks)
+{
+	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, &msg);
+	if (ret)
+		return ret;
+
+	*num_clocks = out.attributes & SCMI_CLK_PROTO_ATTR_COUNT_MASK;
+
+	return 0;
+}
+
+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, &msg);
+	if (ret)
+		return ret;
+
+	*name = out.clock_name;
+
+	return 0;
+}
 
 static int scmi_clk_gate(struct clk *clk, int enable)
 {
@@ -88,6 +134,49 @@ static ulong scmi_clk_set_rate(struct clk *clk, ulong rate)
 	return scmi_clk_get_rate(clk);
 }
 
+static int scmi_clk_probe(struct udevice *dev)
+{
+	struct clk *clk;
+	size_t num_clocks, i;
+	int ret;
+
+	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;
+
+	ret = scmi_clk_get_num_clock(dev, &num_clocks);
+	if (ret)
+		return ret;
+
+	for (i = 0; i < num_clocks; i++) {
+		char *name;
+
+		if (!scmi_clk_get_attibute(dev, i, &name)) {
+			char *clock_name = strdup(name);
+
+			clk = kzalloc(sizeof(*clk), GFP_KERNEL);
+			if (!clk || !clock_name)
+				ret = -ENOMEM;
+			else
+				ret = clk_register(clk, dev->driver->name,
+						   clock_name, dev->name);
+
+			if (ret) {
+				free(clk);
+				free(clock_name);
+				return ret;
+			}
+
+			clk_dm(i, clk);
+		}
+	}
+
+	return 0;
+}
+
 static const struct clk_ops scmi_clk_ops = {
 	.enable = scmi_clk_enable,
 	.disable = scmi_clk_disable,
@@ -99,4 +188,5 @@ U_BOOT_DRIVER(scmi_clock) = {
 	.name = "scmi_clk",
 	.id = UCLASS_CLK,
 	.ops = &scmi_clk_ops,
+	.probe = &scmi_clk_probe,
 };

drivers/firmware/scmi/sandbox-scmi_agent.c

@@ -114,6 +114,55 @@ static struct sandbox_scmi_voltd *get_scmi_voltd_state(uint domain_id)
  * Sandbox SCMI agent ops
  */
 
+static int sandbox_scmi_clock_protocol_attribs(struct udevice *dev,
+					       struct scmi_msg *msg)
+{
+	struct scmi_clk_protocol_attr_out *out = NULL;
+
+	if (!msg->out_msg || msg->out_msg_sz < sizeof(*out))
+		return -EINVAL;
+
+	out = (struct scmi_clk_protocol_attr_out *)msg->out_msg;
+	out->attributes = ARRAY_SIZE(scmi_clk);
+	out->status = SCMI_SUCCESS;
+
+	return 0;
+}
+
+static int sandbox_scmi_clock_attribs(struct udevice *dev, struct scmi_msg *msg)
+{
+	struct scmi_clk_attribute_in *in = NULL;
+	struct scmi_clk_attribute_out *out = NULL;
+	struct sandbox_scmi_clk *clk_state = NULL;
+	int ret;
+
+	if (!msg->in_msg || msg->in_msg_sz < sizeof(*in) ||
+	    !msg->out_msg || msg->out_msg_sz < sizeof(*out))
+		return -EINVAL;
+
+	in = (struct scmi_clk_attribute_in *)msg->in_msg;
+	out = (struct scmi_clk_attribute_out *)msg->out_msg;
+
+	clk_state = get_scmi_clk_state(in->clock_id);
+	if (!clk_state) {
+		dev_err(dev, "Unexpected clock ID %u\n", in->clock_id);
+
+		out->status = SCMI_NOT_FOUND;
+	} else {
+		memset(out, 0, sizeof(*out));
+
+		if (clk_state->enabled)
+			out->attributes = 1;
+
+		ret = snprintf(out->clock_name, sizeof(out->clock_name),
+			       "clk%u", in->clock_id);
+		assert(ret > 0 && ret < sizeof(out->clock_name));
+
+		out->status = SCMI_SUCCESS;
+	}
+
+	return 0;
+}
 static int sandbox_scmi_clock_rate_set(struct udevice *dev,
 				       struct scmi_msg *msg)
 {
@@ -427,6 +476,10 @@ static int sandbox_scmi_test_process_msg(struct udevice *dev,
 	switch (msg->protocol_id) {
 	case SCMI_PROTOCOL_ID_CLOCK:
 		switch (msg->message_id) {
+		case SCMI_PROTOCOL_ATTRIBUTES:
+			return sandbox_scmi_clock_protocol_attribs(dev, msg);
+		case SCMI_CLOCK_ATTRIBUTES:
+			return sandbox_scmi_clock_attribs(dev, msg);
 		case SCMI_CLOCK_RATE_SET:
 			return sandbox_scmi_clock_rate_set(dev, msg);
 		case SCMI_CLOCK_RATE_GET:

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