1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * MDEV driver
  4 *
  5 * Copyright (c) 2016, NVIDIA CORPORATION. All rights reserved.
  6 *     Author: Neo Jia <cjia@nvidia.com>
  7 *             Kirti Wankhede <kwankhede@nvidia.com>
  8 */
  9
 10#include <linux/device.h>
 11#include <linux/iommu.h>
 12#include <linux/mdev.h>
 13
 14#include "mdev_private.h"
 15
 16static int mdev_attach_iommu(struct mdev_device *mdev)
 17{
 18	int ret;
 19	struct iommu_group *group;
 20
 21	group = iommu_group_alloc();
 22	if (IS_ERR(group))
 23		return PTR_ERR(group);
 24
 25	ret = iommu_group_add_device(group, &mdev->dev);
 26	if (!ret)
 27		dev_info(&mdev->dev, "MDEV: group_id = %d\n",
 28			 iommu_group_id(group));
 29
 30	iommu_group_put(group);
 31	return ret;
 32}
 33
 34static void mdev_detach_iommu(struct mdev_device *mdev)
 35{
 36	iommu_group_remove_device(&mdev->dev);
 37	dev_info(&mdev->dev, "MDEV: detaching iommu\n");
 38}
 39
 40static int mdev_probe(struct device *dev)
 41{
 42	struct mdev_driver *drv =
 43		container_of(dev->driver, struct mdev_driver, driver);
 44	struct mdev_device *mdev = to_mdev_device(dev);
 45	int ret;
 46
 47	ret = mdev_attach_iommu(mdev);
 48	if (ret)
 49		return ret;
 50
 51	if (drv->probe) {
 52		ret = drv->probe(mdev);
 53		if (ret)
 54			mdev_detach_iommu(mdev);
 55	}
 56
 57	return ret;
 58}
 59
 60static int mdev_remove(struct device *dev)
 61{
 62	struct mdev_driver *drv =
 63		container_of(dev->driver, struct mdev_driver, driver);
 64	struct mdev_device *mdev = to_mdev_device(dev);
 65
 66	if (drv->remove)
 67		drv->remove(mdev);
 68
 69	mdev_detach_iommu(mdev);
 70
 71	return 0;
 72}
 73
 74static int mdev_match(struct device *dev, struct device_driver *drv)
 75{
 76	/*
 77	 * No drivers automatically match. Drivers are only bound by explicit
 78	 * device_driver_attach()
 79	 */
 80	return 0;
 81}
 82
 83struct bus_type mdev_bus_type = {
 84	.name		= "mdev",
 85	.probe		= mdev_probe,
 86	.remove		= mdev_remove,
 87	.match		= mdev_match,
 88};
 89EXPORT_SYMBOL_GPL(mdev_bus_type);
 90
 91/**
 92 * mdev_register_driver - register a new MDEV driver
 93 * @drv: the driver to register
 94 *
 95 * Returns a negative value on error, otherwise 0.
 96 **/
 97int mdev_register_driver(struct mdev_driver *drv)
 98{
 99	/* initialize common driver fields */
100	drv->driver.bus = &mdev_bus_type;
101
102	/* register with core */
103	return driver_register(&drv->driver);
104}
105EXPORT_SYMBOL(mdev_register_driver);
106
107/*
108 * mdev_unregister_driver - unregister MDEV driver
109 * @drv: the driver to unregister
110 */
111void mdev_unregister_driver(struct mdev_driver *drv)
112{
113	driver_unregister(&drv->driver);
114}
115EXPORT_SYMBOL(mdev_unregister_driver);
116
117int mdev_bus_register(void)
118{
119	return bus_register(&mdev_bus_type);
120}
121
122void mdev_bus_unregister(void)
123{
124	bus_unregister(&mdev_bus_type);
125}