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 = 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 60 static void 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 72 static int mdev_match(struct device *dev, struct device_driver *drv) 73 { 74 /* 75 * No drivers automatically match. Drivers are only bound by explicit 76 * device_driver_attach() 77 */ 78 return 0; 79 } 80 81 struct bus_type mdev_bus_type = { 82 .name = "mdev", 83 .probe = mdev_probe, 84 .remove = mdev_remove, 85 .match = mdev_match, 86 }; 87 EXPORT_SYMBOL_GPL(mdev_bus_type); 88 89 /** 90 * mdev_register_driver - register a new MDEV driver 91 * @drv: the driver to register 92 * 93 * Returns a negative value on error, otherwise 0. 94 **/ 95 int mdev_register_driver(struct mdev_driver *drv) 96 { 97 /* initialize common driver fields */ 98 drv->driver.bus = &mdev_bus_type; 99 100 /* register with core */ 101 return driver_register(&drv->driver); 102 } 103 EXPORT_SYMBOL(mdev_register_driver); 104 105 /* 106 * mdev_unregister_driver - unregister MDEV driver 107 * @drv: the driver to unregister 108 */ 109 void mdev_unregister_driver(struct mdev_driver *drv) 110 { 111 driver_unregister(&drv->driver); 112 } 113 EXPORT_SYMBOL(mdev_unregister_driver); 114 115 int mdev_bus_register(void) 116 { 117 return bus_register(&mdev_bus_type); 118 } 119 120 void mdev_bus_unregister(void) 121 { 122 bus_unregister(&mdev_bus_type); 123 } 124