firmware: arm_scmi: Extend protocol registration interfaces

Extend common protocol registration routines and provide some new generic
protocols get/put helpers that can track protocols usage and automatically
perform the proper initialization and de-initialization on demand when
required.

Convert all standard protocols to use this new registration scheme while
keeping them all still using the usual initialization logic bound to SCMI
devices probing.

Link: https://lore.kernel.org/r/20210316124903.35011-2-cristian.marussi@arm.com
Tested-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

1 files changed, 47 insertions, 12 deletions

diff --git a/drivers/firmware/arm_scmi/bus.c b/drivers/firmware/arm_scmi/bus.c
index 1377ec76a45d..4e8f6ea355dd 100644
--- a/drivers/firmware/arm_scmi/bus.c
+++ b/drivers/firmware/arm_scmi/bus.c
@@ -2,7 +2,7 @@
 /*
  * System Control and Management Interface (SCMI) Message Protocol bus layer
  *
- * Copyright (C) 2018 ARM Ltd.
+ * Copyright (C) 2018-2021 ARM Ltd.
  */
 
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
@@ -51,13 +51,29 @@ static int scmi_dev_match(struct device *dev, struct device_driver *drv)
 	return 0;
 }
 
+const struct scmi_protocol *scmi_protocol_get(int protocol_id)
+{
+	const struct scmi_protocol *proto;
+
+	proto = idr_find(&scmi_protocols, protocol_id);
+	if (!proto) {
+		pr_warn("SCMI Protocol 0x%x not found!\n", protocol_id);
+		return NULL;
+	}
+
+	pr_debug("Found SCMI Protocol 0x%x\n", protocol_id);
+
+	return proto;
+}
+
 static int scmi_protocol_init(int protocol_id, struct scmi_handle *handle)
 {
-	scmi_prot_init_fn_t fn = idr_find(&scmi_protocols, protocol_id);
+	const struct scmi_protocol *proto;
 
-	if (unlikely(!fn))
+	proto = scmi_protocol_get(protocol_id);
+	if (!proto)
 		return -EINVAL;
-	return fn(handle);
+	return proto->init(handle);
 }
 
 static int scmi_protocol_dummy_init(struct scmi_handle *handle)
@@ -194,26 +210,45 @@ void scmi_set_handle(struct scmi_device *scmi_dev)
 	scmi_dev->handle = scmi_handle_get(&scmi_dev->dev);
 }
 
-int scmi_protocol_register(int protocol_id, scmi_prot_init_fn_t fn)
+int scmi_protocol_register(const struct scmi_protocol *proto)
 {
 	int ret;
 
+	if (!proto) {
+		pr_err("invalid protocol\n");
+		return -EINVAL;
+	}
+
+	if (!proto->init && !proto->instance_init) {
+		pr_err("missing init for protocol 0x%x\n", proto->id);
+		return -EINVAL;
+	}
+
 	spin_lock(&protocol_lock);
-	ret = idr_alloc(&scmi_protocols, fn, protocol_id, protocol_id + 1,
-			GFP_ATOMIC);
+	ret = idr_alloc(&scmi_protocols, (void *)proto,
+			proto->id, proto->id + 1, GFP_ATOMIC);
 	spin_unlock(&protocol_lock);
-	if (ret != protocol_id)
-		pr_err("unable to allocate SCMI idr slot, err %d\n", ret);
+	if (ret != proto->id) {
+		pr_err("unable to allocate SCMI idr slot for 0x%x - err %d\n",
+		       proto->id, ret);
+		return ret;
+	}
+
+	pr_debug("Registered SCMI Protocol 0x%x\n", proto->id);
 
-	return ret;
+	return 0;
 }
 EXPORT_SYMBOL_GPL(scmi_protocol_register);
 
-void scmi_protocol_unregister(int protocol_id)
+void scmi_protocol_unregister(const struct scmi_protocol *proto)
 {
 	spin_lock(&protocol_lock);
-	idr_remove(&scmi_protocols, protocol_id);
+	idr_remove(&scmi_protocols, proto->id);
 	spin_unlock(&protocol_lock);
+
+	pr_debug("Unregistered SCMI Protocol 0x%x\n", proto->id);
+
+	return;
 }
 EXPORT_SYMBOL_GPL(scmi_protocol_unregister);