1 files changed, 252 insertions, 0 deletions

diff --git a/drivers/firmware/arm_scmi/bus.c b/drivers/firmware/arm_scmi/bus.c
new file mode 100644
index 000000000..def8a84d1
--- /dev/null
+++ b/drivers/firmware/arm_scmi/bus.c
@@ -0,0 +1,252 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * System Control and Management Interface (SCMI) Message Protocol bus layer
+ *
+ * Copyright (C) 2018 ARM Ltd.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/types.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/device.h>
+
+#include "common.h"
+
+static DEFINE_IDA(scmi_bus_id);
+static DEFINE_IDR(scmi_protocols);
+static DEFINE_SPINLOCK(protocol_lock);
+
+static const struct scmi_device_id *
+scmi_dev_match_id(struct scmi_device *scmi_dev, struct scmi_driver *scmi_drv)
+{
+	const struct scmi_device_id *id = scmi_drv->id_table;
+
+	if (!id)
+		return NULL;
+
+	for (; id->protocol_id; id++)
+		if (id->protocol_id == scmi_dev->protocol_id) {
+			if (!id->name)
+				return id;
+			else if (!strcmp(id->name, scmi_dev->name))
+				return id;
+		}
+
+	return NULL;
+}
+
+static int scmi_dev_match(struct device *dev, struct device_driver *drv)
+{
+	struct scmi_driver *scmi_drv = to_scmi_driver(drv);
+	struct scmi_device *scmi_dev = to_scmi_dev(dev);
+	const struct scmi_device_id *id;
+
+	id = scmi_dev_match_id(scmi_dev, scmi_drv);
+	if (id)
+		return 1;
+
+	return 0;
+}
+
+static int scmi_protocol_init(int protocol_id, struct scmi_handle *handle)
+{
+	scmi_prot_init_fn_t fn = idr_find(&scmi_protocols, protocol_id);
+
+	if (unlikely(!fn))
+		return -EINVAL;
+	return fn(handle);
+}
+
+static int scmi_protocol_dummy_init(struct scmi_handle *handle)
+{
+	return 0;
+}
+
+static int scmi_dev_probe(struct device *dev)
+{
+	struct scmi_driver *scmi_drv = to_scmi_driver(dev->driver);
+	struct scmi_device *scmi_dev = to_scmi_dev(dev);
+	const struct scmi_device_id *id;
+	int ret;
+
+	id = scmi_dev_match_id(scmi_dev, scmi_drv);
+	if (!id)
+		return -ENODEV;
+
+	if (!scmi_dev->handle)
+		return -EPROBE_DEFER;
+
+	ret = scmi_protocol_init(scmi_dev->protocol_id, scmi_dev->handle);
+	if (ret)
+		return ret;
+
+	/* Skip protocol initialisation for additional devices */
+	idr_replace(&scmi_protocols, &scmi_protocol_dummy_init,
+		    scmi_dev->protocol_id);
+
+	return scmi_drv->probe(scmi_dev);
+}
+
+static int scmi_dev_remove(struct device *dev)
+{
+	struct scmi_driver *scmi_drv = to_scmi_driver(dev->driver);
+	struct scmi_device *scmi_dev = to_scmi_dev(dev);
+
+	if (scmi_drv->remove)
+		scmi_drv->remove(scmi_dev);
+
+	return 0;
+}
+
+static struct bus_type scmi_bus_type = {
+	.name =	"scmi_protocol",
+	.match = scmi_dev_match,
+	.probe = scmi_dev_probe,
+	.remove = scmi_dev_remove,
+};
+
+int scmi_driver_register(struct scmi_driver *driver, struct module *owner,
+			 const char *mod_name)
+{
+	int retval;
+
+	if (!driver->probe)
+		return -EINVAL;
+
+	driver->driver.bus = &scmi_bus_type;
+	driver->driver.name = driver->name;
+	driver->driver.owner = owner;
+	driver->driver.mod_name = mod_name;
+
+	retval = driver_register(&driver->driver);
+	if (!retval)
+		pr_debug("registered new scmi driver %s\n", driver->name);
+
+	return retval;
+}
+EXPORT_SYMBOL_GPL(scmi_driver_register);
+
+void scmi_driver_unregister(struct scmi_driver *driver)
+{
+	driver_unregister(&driver->driver);
+}
+EXPORT_SYMBOL_GPL(scmi_driver_unregister);
+
+static void scmi_device_release(struct device *dev)
+{
+	kfree(to_scmi_dev(dev));
+}
+
+struct scmi_device *
+scmi_device_create(struct device_node *np, struct device *parent, int protocol,
+		   const char *name)
+{
+	int id, retval;
+	struct scmi_device *scmi_dev;
+
+	scmi_dev = kzalloc(sizeof(*scmi_dev), GFP_KERNEL);
+	if (!scmi_dev)
+		return NULL;
+
+	scmi_dev->name = kstrdup_const(name ?: "unknown", GFP_KERNEL);
+	if (!scmi_dev->name) {
+		kfree(scmi_dev);
+		return NULL;
+	}
+
+	id = ida_simple_get(&scmi_bus_id, 1, 0, GFP_KERNEL);
+	if (id < 0) {
+		kfree_const(scmi_dev->name);
+		kfree(scmi_dev);
+		return NULL;
+	}
+
+	scmi_dev->id = id;
+	scmi_dev->protocol_id = protocol;
+	scmi_dev->dev.parent = parent;
+	scmi_dev->dev.of_node = np;
+	scmi_dev->dev.bus = &scmi_bus_type;
+	scmi_dev->dev.release = scmi_device_release;
+	dev_set_name(&scmi_dev->dev, "scmi_dev.%d", id);
+
+	retval = device_register(&scmi_dev->dev);
+	if (retval)
+		goto put_dev;
+
+	return scmi_dev;
+put_dev:
+	kfree_const(scmi_dev->name);
+	put_device(&scmi_dev->dev);
+	ida_simple_remove(&scmi_bus_id, id);
+	return NULL;
+}
+
+void scmi_device_destroy(struct scmi_device *scmi_dev)
+{
+	kfree_const(scmi_dev->name);
+	scmi_handle_put(scmi_dev->handle);
+	ida_simple_remove(&scmi_bus_id, scmi_dev->id);
+	device_unregister(&scmi_dev->dev);
+}
+
+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 ret;
+
+	spin_lock(&protocol_lock);
+	ret = idr_alloc(&scmi_protocols, fn, protocol_id, protocol_id + 1,
+			GFP_ATOMIC);
+	spin_unlock(&protocol_lock);
+	if (ret != protocol_id)
+		pr_err("unable to allocate SCMI idr slot, err %d\n", ret);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(scmi_protocol_register);
+
+void scmi_protocol_unregister(int protocol_id)
+{
+	spin_lock(&protocol_lock);
+	idr_remove(&scmi_protocols, protocol_id);
+	spin_unlock(&protocol_lock);
+}
+EXPORT_SYMBOL_GPL(scmi_protocol_unregister);
+
+static int __scmi_devices_unregister(struct device *dev, void *data)
+{
+	struct scmi_device *scmi_dev = to_scmi_dev(dev);
+
+	scmi_device_destroy(scmi_dev);
+	return 0;
+}
+
+static void scmi_devices_unregister(void)
+{
+	bus_for_each_dev(&scmi_bus_type, NULL, NULL, __scmi_devices_unregister);
+}
+
+int __init scmi_bus_init(void)
+{
+	int retval;
+
+	retval = bus_register(&scmi_bus_type);
+	if (retval)
+		pr_err("scmi protocol bus register failed (%d)\n", retval);
+
+	return retval;
+}
+
+void __exit scmi_bus_exit(void)
+{
+	scmi_devices_unregister();
+	bus_unregister(&scmi_bus_type);
+	ida_destroy(&scmi_bus_id);
+}