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 = to_mdev_driver(dev->driver);
 43	struct mdev_device *mdev = to_mdev_device(dev);
 44	int ret;
 45
 46	ret = mdev_attach_iommu(mdev);
 47	if (ret)
 48		return ret;
 49
 50	if (drv && drv->probe) {
 51		ret = drv->probe(dev);
 52		if (ret)
 53			mdev_detach_iommu(mdev);
 54	}
 55
 56	return ret;
 57}
 58
 59static int mdev_remove(struct device *dev)
 60{
 61	struct mdev_driver *drv = to_mdev_driver(dev->driver);
 62	struct mdev_device *mdev = to_mdev_device(dev);
 63
 64	if (drv && drv->remove)
 65		drv->remove(dev);
 66
 67	mdev_detach_iommu(mdev);
 68
 69	return 0;
 70}
 71
 72struct bus_type mdev_bus_type = {
 73	.name		= "mdev",
 74	.probe		= mdev_probe,
 75	.remove		= mdev_remove,
 76};
 77EXPORT_SYMBOL_GPL(mdev_bus_type);
 78
 79/**
 80 * mdev_register_driver - register a new MDEV driver
 81 * @drv: the driver to register
 82 * @owner: module owner of driver to be registered
 83 *
 84 * Returns a negative value on error, otherwise 0.
 85 **/
 86int mdev_register_driver(struct mdev_driver *drv, struct module *owner)
 87{
 88	/* initialize common driver fields */
 89	drv->driver.name = drv->name;
 90	drv->driver.bus = &mdev_bus_type;
 91	drv->driver.owner = owner;
 92
 93	/* register with core */
 94	return driver_register(&drv->driver);
 95}
 96EXPORT_SYMBOL(mdev_register_driver);
 97
 98/*
 99 * mdev_unregister_driver - unregister MDEV driver
100 * @drv: the driver to unregister
101 */
102void mdev_unregister_driver(struct mdev_driver *drv)
103{
104	driver_unregister(&drv->driver);
105}
106EXPORT_SYMBOL(mdev_unregister_driver);
107
108int mdev_bus_register(void)
109{
110	return bus_register(&mdev_bus_type);
111}
112
113void mdev_bus_unregister(void)
114{
115	bus_unregister(&mdev_bus_type);
116}