--- /dev/null
+// 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>
+
+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)) {
+ 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);
+
+ if (!ffa_device_match(dev, dev->driver))
+ return -ENODEV;
+
+ return ffa_drv->probe(ffa_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,
+ .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;
+
+ 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);
+
+ kfree(ffa_dev);
+}
+
+static int __ffa_devices_unregister(struct device *dev, void *data)
+{
+ ffa_release_device(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)
+{
+ int ret;
+ struct device *dev;
+ struct ffa_device *ffa_dev;
+
+ ffa_dev = kzalloc(sizeof(*ffa_dev), GFP_KERNEL);
+ if (!ffa_dev)
+ return NULL;
+
+ dev = &ffa_dev->dev;
+ dev->bus = &ffa_bus_type;
+ dev->release = ffa_release_device;
+ dev_set_name(&ffa_dev->dev, "arm-ffa-%04x", vm_id);
+
+ ffa_dev->vm_id = vm_id;
+ 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);
+
+static int __init arm_ffa_bus_init(void)
+{
+ return bus_register(&ffa_bus_type);
+}
+module_init(arm_ffa_bus_init);
+
+static void __exit arm_ffa_bus_exit(void)
+{
+ ffa_devices_unregister();
+ bus_unregister(&ffa_bus_type);
+}
+
+module_exit(arm_ffa_bus_exit);
+
+MODULE_ALIAS("arm-ffa-bus");
+MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
+MODULE_DESCRIPTION("Arm FF-A bus driver");
+MODULE_LICENSE("GPL v2");
--- /dev/null
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2021 ARM Ltd.
+ */
+
+#ifndef _LINUX_ARM_FFA_H
+#define _LINUX_ARM_FFA_H
+
+#include <linux/cdev.h>
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/uuid.h>
+
+/* FFA Bus/Device/Driver related */
+struct ffa_device {
+ int vm_id;
+ uuid_t uuid;
+ struct device dev;
+};
+
+#define to_ffa_dev(d) container_of(d, struct ffa_device, dev)
+
+struct ffa_device_id {
+ uuid_t uuid;
+};
+
+struct ffa_driver {
+ const char *name;
+ int (*probe)(struct ffa_device *sdev);
+ void (*remove)(struct ffa_device *sdev);
+ const struct ffa_device_id *id_table;
+
+ struct device_driver driver;
+};
+
+#define to_ffa_driver(d) container_of(d, struct ffa_driver, driver)
+
+static inline void ffa_dev_set_drvdata(struct ffa_device *fdev, void *data)
+{
+ fdev->dev.driver_data = data;
+}
+
+#if IS_REACHABLE(CONFIG_ARM_FFA_TRANSPORT)
+struct ffa_device *ffa_device_register(const uuid_t *uuid, int vm_id);
+void ffa_device_unregister(struct ffa_device *ffa_dev);
+int ffa_driver_register(struct ffa_driver *driver, struct module *owner,
+ const char *mod_name);
+void ffa_driver_unregister(struct ffa_driver *driver);
+bool ffa_device_is_valid(struct ffa_device *ffa_dev);
+
+#else
+static inline
+struct ffa_device *ffa_device_register(const uuid_t *uuid, int vm_id)
+{
+ return NULL;
+}
+
+static inline void ffa_device_unregister(struct ffa_device *dev) {}
+
+static inline int
+ffa_driver_register(struct ffa_driver *driver, struct module *owner,
+ const char *mod_name)
+{
+ return -EINVAL;
+}
+
+static inline void ffa_driver_unregister(struct ffa_driver *driver) {}
+
+static inline
+bool ffa_device_is_valid(struct ffa_device *ffa_dev) { return false; }
+
+#endif /* CONFIG_ARM_FFA_TRANSPORT */
+
+#define ffa_register(driver) \
+ ffa_driver_register(driver, THIS_MODULE, KBUILD_MODNAME)
+#define ffa_unregister(driver) \
+ ffa_driver_unregister(driver)
+
+/**
+ * module_ffa_driver() - Helper macro for registering a psa_ffa driver
+ * @__ffa_driver: ffa_driver structure
+ *
+ * Helper macro for psa_ffa drivers to set up proper module init / exit
+ * functions. Replaces module_init() and module_exit() and keeps people from
+ * printing pointless things to the kernel log when their driver is loaded.
+ */
+#define module_ffa_driver(__ffa_driver) \
+ module_driver(__ffa_driver, ffa_register, ffa_unregister)
+
+#endif /* _LINUX_ARM_FFA_H */
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