drivers/vfio/mdev/mdev_driver.c

   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
  16 static 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
  34 static 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
  40 static 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
  59 static 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
  72 struct bus_type mdev_bus_type = {
  73         .name           = "mdev",
  74         .probe          = mdev_probe,
  75         .remove         = mdev_remove,
  76 };
  77 EXPORT_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  **/
  86 int 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 }
  96 EXPORT_SYMBOL(mdev_register_driver);
  97
  98 /*
  99  * mdev_unregister_driver - unregister MDEV driver
 100  * @drv: the driver to unregister
 101  */
 102 void mdev_unregister_driver(struct mdev_driver *drv)
 103 {
 104         driver_unregister(&drv->driver);
 105 }
 106 EXPORT_SYMBOL(mdev_unregister_driver);
 107
 108 int mdev_bus_register(void)
 109 {
 110         return bus_register(&mdev_bus_type);
 111 }
 112
 113 void mdev_bus_unregister(void)
 114 {
 115         bus_unregister(&mdev_bus_type);
 116 }