1 files changed, 232 insertions, 0 deletions
diff --git a/drivers/firmware/arm_ffa/bus.c b/drivers/firmware/arm_ffa/bus.c
new file mode 100644
index 000000000..248594b59
--- /dev/null
+++ b/drivers/firmware/arm_ffa/bus.c
@@ -0,0 +1,232 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2021 ARM Ltd.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/arm_ffa.h>
+#include <linux/device.h>
+#include <linux/fs.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+
+#include "common.h"
+
+static DEFINE_IDA(ffa_bus_id);
+
+static int ffa_device_match(struct device *dev, struct device_driver *drv)
+{
+	const struct ffa_device_id *id_table;
+	struct ffa_device *ffa_dev;
+
+	id_table = to_ffa_driver(drv)->id_table;
+	ffa_dev = to_ffa_dev(dev);
+
+	while (!uuid_is_null(&id_table->uuid)) {
+		/*
+		 * FF-A v1.0 doesn't provide discovery of UUIDs, just the
+		 * partition IDs, so fetch the partitions IDs for this
+		 * id_table UUID and assign the UUID to the device if the
+		 * partition ID matches
+		 */
+		if (uuid_is_null(&ffa_dev->uuid))
+			ffa_device_match_uuid(ffa_dev, &id_table->uuid);
+
+		if (uuid_equal(&ffa_dev->uuid, &id_table->uuid))
+			return 1;
+		id_table++;
+	}
+
+	return 0;
+}
+
+static int ffa_device_probe(struct device *dev)
+{
+	struct ffa_driver *ffa_drv = to_ffa_driver(dev->driver);
+	struct ffa_device *ffa_dev = to_ffa_dev(dev);
+
+	return ffa_drv->probe(ffa_dev);
+}
+
+static void ffa_device_remove(struct device *dev)
+{
+	struct ffa_driver *ffa_drv = to_ffa_driver(dev->driver);
+
+	if (ffa_drv->remove)
+		ffa_drv->remove(to_ffa_dev(dev));
+}
+
+static int ffa_device_uevent(struct device *dev, struct kobj_uevent_env *env)
+{
+	struct ffa_device *ffa_dev = to_ffa_dev(dev);
+
+	return add_uevent_var(env, "MODALIAS=arm_ffa:%04x:%pUb",
+			      ffa_dev->vm_id, &ffa_dev->uuid);
+}
+
+static ssize_t partition_id_show(struct device *dev,
+				 struct device_attribute *attr, char *buf)
+{
+	struct ffa_device *ffa_dev = to_ffa_dev(dev);
+
+	return sprintf(buf, "0x%04x\n", ffa_dev->vm_id);
+}
+static DEVICE_ATTR_RO(partition_id);
+
+static ssize_t uuid_show(struct device *dev, struct device_attribute *attr,
+			 char *buf)
+{
+	struct ffa_device *ffa_dev = to_ffa_dev(dev);
+
+	return sprintf(buf, "%pUb\n", &ffa_dev->uuid);
+}
+static DEVICE_ATTR_RO(uuid);
+
+static struct attribute *ffa_device_attributes_attrs[] = {
+	&dev_attr_partition_id.attr,
+	&dev_attr_uuid.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(ffa_device_attributes);
+
+struct bus_type ffa_bus_type = {
+	.name		= "arm_ffa",
+	.match		= ffa_device_match,
+	.probe		= ffa_device_probe,
+	.remove		= ffa_device_remove,
+	.uevent		= ffa_device_uevent,
+	.dev_groups	= ffa_device_attributes_groups,
+};
+EXPORT_SYMBOL_GPL(ffa_bus_type);
+
+int ffa_driver_register(struct ffa_driver *driver, struct module *owner,
+			const char *mod_name)
+{
+	int ret;
+
+	if (!driver->probe)
+		return -EINVAL;
+
+	driver->driver.bus = &ffa_bus_type;
+	driver->driver.name = driver->name;
+	driver->driver.owner = owner;
+	driver->driver.mod_name = mod_name;
+
+	ret = driver_register(&driver->driver);
+	if (!ret)
+		pr_debug("registered new ffa driver %s\n", driver->name);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(ffa_driver_register);
+
+void ffa_driver_unregister(struct ffa_driver *driver)
+{
+	driver_unregister(&driver->driver);
+}
+EXPORT_SYMBOL_GPL(ffa_driver_unregister);
+
+static void ffa_release_device(struct device *dev)
+{
+	struct ffa_device *ffa_dev = to_ffa_dev(dev);
+
+	ida_free(&ffa_bus_id, ffa_dev->id);
+	kfree(ffa_dev);
+}
+
+static int __ffa_devices_unregister(struct device *dev, void *data)
+{
+	device_unregister(dev);
+
+	return 0;
+}
+
+static void ffa_devices_unregister(void)
+{
+	bus_for_each_dev(&ffa_bus_type, NULL, NULL,
+			 __ffa_devices_unregister);
+}
+
+bool ffa_device_is_valid(struct ffa_device *ffa_dev)
+{
+	bool valid = false;
+	struct device *dev = NULL;
+	struct ffa_device *tmp_dev;
+
+	do {
+		dev = bus_find_next_device(&ffa_bus_type, dev);
+		tmp_dev = to_ffa_dev(dev);
+		if (tmp_dev == ffa_dev) {
+			valid = true;
+			break;
+		}
+		put_device(dev);
+	} while (dev);
+
+	put_device(dev);
+
+	return valid;
+}
+
+struct ffa_device *ffa_device_register(const uuid_t *uuid, int vm_id,
+				       const struct ffa_ops *ops)
+{
+	int id, ret;
+	struct device *dev;
+	struct ffa_device *ffa_dev;
+
+	id = ida_alloc_min(&ffa_bus_id, 1, GFP_KERNEL);
+	if (id < 0)
+		return NULL;
+
+	ffa_dev = kzalloc(sizeof(*ffa_dev), GFP_KERNEL);
+	if (!ffa_dev) {
+		ida_free(&ffa_bus_id, id);
+		return NULL;
+	}
+
+	dev = &ffa_dev->dev;
+	dev->bus = &ffa_bus_type;
+	dev->release = ffa_release_device;
+	dev_set_name(&ffa_dev->dev, "arm-ffa-%d", id);
+
+	ffa_dev->id = id;
+	ffa_dev->vm_id = vm_id;
+	ffa_dev->ops = ops;
+	uuid_copy(&ffa_dev->uuid, uuid);
+
+	ret = device_register(&ffa_dev->dev);
+	if (ret) {
+		dev_err(dev, "unable to register device %s err=%d\n",
+			dev_name(dev), ret);
+		put_device(dev);
+		return NULL;
+	}
+
+	return ffa_dev;
+}
+EXPORT_SYMBOL_GPL(ffa_device_register);
+
+void ffa_device_unregister(struct ffa_device *ffa_dev)
+{
+	if (!ffa_dev)
+		return;
+
+	device_unregister(&ffa_dev->dev);
+}
+EXPORT_SYMBOL_GPL(ffa_device_unregister);
+
+int arm_ffa_bus_init(void)
+{
+	return bus_register(&ffa_bus_type);
+}
+
+void arm_ffa_bus_exit(void)
+{
+	ffa_devices_unregister();
+	bus_unregister(&ffa_bus_type);
+	ida_destroy(&ffa_bus_id);
+}