1/*
  2 * MDEV driver
  3 *
  4 * Copyright (c) 2016, NVIDIA CORPORATION. All rights reserved.
  5 *     Author: Neo Jia <cjia@nvidia.com>
  6 *             Kirti Wankhede <kwankhede@nvidia.com>
  7 *
  8 * This program is free software; you can redistribute it and/or modify
  9 * it under the terms of the GNU General Public License version 2 as
 10 * published by the Free Software Foundation.
 11 */
 12
 13#include <linux/device.h>
 14#include <linux/iommu.h>
 15#include <linux/mdev.h>
 16
 17#include "mdev_private.h"
 18
 19static int mdev_attach_iommu(struct mdev_device *mdev)
 20{
 21	int ret;
 22	struct iommu_group *group;
 23
 24	group = iommu_group_alloc();
 25	if (IS_ERR(group))
 26		return PTR_ERR(group);
 27
 28	ret = iommu_group_add_device(group, &mdev->dev);
 29	if (!ret)
 30		dev_info(&mdev->dev, "MDEV: group_id = %d\n",
 31			 iommu_group_id(group));
 32
 33	iommu_group_put(group);
 34	return ret;
 35}
 36
 37static void mdev_detach_iommu(struct mdev_device *mdev)
 38{
 39	iommu_group_remove_device(&mdev->dev);
 40	dev_info(&mdev->dev, "MDEV: detaching iommu\n");
 41}
 42
 43static int mdev_probe(struct device *dev)
 44{
 45	struct mdev_driver *drv = to_mdev_driver(dev->driver);
 46	struct mdev_device *mdev = to_mdev_device(dev);
 47	int ret;
 48
 49	ret = mdev_attach_iommu(mdev);
 50	if (ret)
 51		return ret;
 52
 53	if (drv && drv->probe) {
 54		ret = drv->probe(dev);
 55		if (ret)
 56			mdev_detach_iommu(mdev);
 57	}
 58
 59	return ret;
 60}
 61
 62static int mdev_remove(struct device *dev)
 63{
 64	struct mdev_driver *drv = to_mdev_driver(dev->driver);
 65	struct mdev_device *mdev = to_mdev_device(dev);
 66
 67	if (drv && drv->remove)
 68		drv->remove(dev);
 69
 70	mdev_detach_iommu(mdev);
 71
 72	return 0;
 73}
 74
 75struct bus_type mdev_bus_type = {
 76	.name		= "mdev",
 77	.probe		= mdev_probe,
 78	.remove		= mdev_remove,
 79};
 80EXPORT_SYMBOL_GPL(mdev_bus_type);
 81
 82/**
 83 * mdev_register_driver - register a new MDEV driver
 84 * @drv: the driver to register
 85 * @owner: module owner of driver to be registered
 86 *
 87 * Returns a negative value on error, otherwise 0.
 88 **/
 89int mdev_register_driver(struct mdev_driver *drv, struct module *owner)
 90{
 91	/* initialize common driver fields */
 92	drv->driver.name = drv->name;
 93	drv->driver.bus = &mdev_bus_type;
 94	drv->driver.owner = owner;
 95
 96	/* register with core */
 97	return driver_register(&drv->driver);
 98}
 99EXPORT_SYMBOL(mdev_register_driver);
100
101/*
102 * mdev_unregister_driver - unregister MDEV driver
103 * @drv: the driver to unregister
104 */
105void mdev_unregister_driver(struct mdev_driver *drv)
106{
107	driver_unregister(&drv->driver);
108}
109EXPORT_SYMBOL(mdev_unregister_driver);
110
111int mdev_bus_register(void)
112{
113	return bus_register(&mdev_bus_type);
114}
115
116void mdev_bus_unregister(void)
117{
118	bus_unregister(&mdev_bus_type);
119}