[PATCH 02/10] firmware: scmi: framework for installing additional protocols

[AKASHI Takahiro]

This framework allows SCMI protocols to be installed and bound to the agent
so that the agent can manage and utilize them later.

Signed-off-by: AKASHI Takahiro <takahiro.akashi at linaro.org>
---
 drivers/firmware/scmi/scmi_agent-uclass.c | 105 +++++++++++++++++++++-
 include/scmi_agent-uclass.h               |  12 +++
 include/scmi_agent.h                      |  14 +++
 3 files changed, 128 insertions(+), 3 deletions(-)

diff --git a/drivers/firmware/scmi/scmi_agent-uclass.c b/drivers/firmware/scmi/scmi_agent-uclass.c
index 02de692d66f3..6fd948ae6ddf 100644
--- a/drivers/firmware/scmi/scmi_agent-uclass.c
+++ b/drivers/firmware/scmi/scmi_agent-uclass.c
@@ -37,6 +37,86 @@ static const struct error_code scmi_linux_errmap[] = {
 	{ .scmi = SCMI_PROTOCOL_ERROR, .errno = -EPROTO, },
 };
 
+/*
+ * NOTE: The only one instance should exist according to
+ * the current specification and device tree bindings.
+ */
+struct udevice *scmi_agent;
+
+struct udevice *scmi_get_protocol(struct udevice *dev,
+				  enum scmi_std_protocol id)
+{
+	struct scmi_agent_priv *priv;
+	struct udevice *proto;
+
+	priv = dev_get_uclass_plat(dev);
+	if (!priv) {
+		dev_err(dev, "No priv data found\n");
+		return NULL;
+	}
+
+	switch (id) {
+	case SCMI_PROTOCOL_ID_CLOCK:
+		proto = priv->clock_dev;
+		break;
+	case SCMI_PROTOCOL_ID_RESET_DOMAIN:
+		proto = priv->resetdom_dev;
+		break;
+	case SCMI_PROTOCOL_ID_VOLTAGE_DOMAIN:
+		proto = priv->voltagedom_dev;
+		break;
+	default:
+		dev_err(dev, "Protocol not supported\n");
+		proto = NULL;
+		break;
+	}
+	if (proto && device_probe(proto))
+		dev_err(dev, "Probe failed\n");
+
+	return proto;
+}
+
+/**
+ * scmi_add_protocol - add protocol to agent
+ * @dev:	SCMI device
+ * @proto_id:	Identifier of protocol
+ * @proto:	Device of protocol instance
+ *
+ * Associate the protocol instance, @proto, to the agent, @dev,
+ * for later use.
+ *
+ * Return:	0 on success, error code otherwise
+ */
+static int scmi_add_protocol(struct udevice *dev,
+			     enum scmi_std_protocol proto_id,
+			     struct udevice *proto)
+{
+	struct scmi_agent_priv *priv;
+
+	priv = dev_get_uclass_plat(dev);
+	if (!priv) {
+		dev_err(dev, "No priv data found\n");
+		return -ENODEV;
+	}
+
+	switch (proto_id) {
+	case SCMI_PROTOCOL_ID_CLOCK:
+		priv->clock_dev = proto;
+		break;
+	case SCMI_PROTOCOL_ID_RESET_DOMAIN:
+		priv->resetdom_dev = proto;
+		break;
+	case SCMI_PROTOCOL_ID_VOLTAGE_DOMAIN:
+		priv->voltagedom_dev = proto;
+		break;
+	default:
+		dev_err(dev, "Protocol not supported\n");
+		return -EPROTO;
+	}
+
+	return 0;
+}
+
 int scmi_to_linux_errno(s32 scmi_code)
 {
 	int n;
@@ -61,9 +141,15 @@ static int scmi_bind_protocols(struct udevice *dev)
 	int ret = 0;
 	ofnode node;
 	const char *name;
+	struct driver *drv;
+	struct udevice *proto;
+
+	if (scmi_agent) {
+		dev_err(dev, "SCMI agent already exists: %s\n", dev->name);
+		return -EBUSY;
+	}
 
 	dev_for_each_subnode(node, dev) {
-		struct driver *drv = NULL;
 		u32 protocol_id;
 
 		if (!ofnode_is_enabled(node))
@@ -72,6 +158,7 @@ static int scmi_bind_protocols(struct udevice *dev)
 		if (ofnode_read_u32(node, "reg", &protocol_id))
 			continue;
 
+		drv = NULL;
 		name = ofnode_get_name(node);
 		switch (protocol_id) {
 		case SCMI_PROTOCOL_ID_CLOCK:
@@ -102,11 +189,22 @@ static int scmi_bind_protocols(struct udevice *dev)
 			continue;
 		}
 
-		ret = device_bind(dev, drv, name, NULL, node, NULL);
-		if (ret)
+		ret = device_bind(dev, drv, name, NULL, node, &proto);
+		if (ret) {
+			dev_err(dev, "failed to bind %s protocol\n", drv->name);
 			break;
+		}
+		ret = scmi_add_protocol(dev, protocol_id, proto);
+		if (ret) {
+			dev_err(dev, "failed to add protocol: %s, ret: %d\n",
+				proto->name, ret);
+			break;
+		}
 	}
 
+	if (!ret)
+		scmi_agent = dev;
+
 	return ret;
 }
 
@@ -168,4 +266,5 @@ UCLASS_DRIVER(scmi_agent) = {
 	.id		= UCLASS_SCMI_AGENT,
 	.name		= "scmi_agent",
 	.post_bind	= scmi_bind_protocols,
+	.per_device_plat_auto = sizeof(struct scmi_agent_priv),
 };
diff --git a/include/scmi_agent-uclass.h b/include/scmi_agent-uclass.h
index b1c93532c0ea..6c3d1321b1aa 100644
--- a/include/scmi_agent-uclass.h
+++ b/include/scmi_agent-uclass.h
@@ -9,6 +9,18 @@ struct udevice;
 struct scmi_msg;
 struct scmi_channel;
 
+/**
+ * struct scmi_agent_priv - private data maintained by agent instance
+ * @clock_dev:	SCMI clock protocol device
+ * @clock_dev:	SCMI reset domain protocol device
+ * @clock_dev:	SCMI voltage domain protocol device
+ */
+struct scmi_agent_priv {
+	struct udevice *clock_dev;
+	struct udevice *resetdom_dev;
+	struct udevice *voltagedom_dev;
+};
+
 /**
  * struct scmi_transport_ops - The functions that a SCMI transport layer must implement.
  */
diff --git a/include/scmi_agent.h b/include/scmi_agent.h
index ee6286366df7..f77c10f7abfd 100644
--- a/include/scmi_agent.h
+++ b/include/scmi_agent.h
@@ -11,6 +11,7 @@
 #define SCMI_AGENT_H
 
 #include <asm/types.h>
+#include <scmi_protocols.h>
 
 struct udevice;
 struct scmi_channel;
@@ -69,6 +70,19 @@ int devm_scmi_of_get_channel(struct udevice *dev, struct scmi_channel **channel)
 int devm_scmi_process_msg(struct udevice *dev, struct scmi_channel *channel,
 			  struct scmi_msg *msg);
 
+/**
+ * scmi_get_protocol() - get protocol instance
+ *
+ * @dev:	SCMI device
+ * @id:		Identifier of protocol
+ *
+ * Obtain the device instance for given protocol ID, @id.
+ *
+ * Return:	Pointer to the device if found, null otherwise
+ */
+struct udevice *scmi_get_protocol(struct udevice *dev,
+				  enum scmi_std_protocol id);
+
 /**
  * scmi_to_linux_errno() - Convert an SCMI error code into a Linux errno code
  *
-- 
2.41.0