Oleksandr Tyshchenko | 1ca55d50 | 2022-06-02 22:23:51 +0300 | [diff] [blame] | 1 | // SPDX-License-Identifier: GPL-2.0 |
| 2 | /* |
| 3 | * Stub IOMMU driver which does nothing. |
| 4 | * The main purpose of it being present is to reuse generic IOMMU device tree |
| 5 | * bindings by Xen grant DMA-mapping layer. |
| 6 | * |
| 7 | * Copyright (C) 2022 EPAM Systems Inc. |
| 8 | */ |
| 9 | |
| 10 | #include <linux/iommu.h> |
| 11 | #include <linux/of.h> |
| 12 | #include <linux/platform_device.h> |
| 13 | |
| 14 | struct grant_dma_iommu_device { |
| 15 | struct device *dev; |
| 16 | struct iommu_device iommu; |
| 17 | }; |
| 18 | |
| 19 | /* Nothing is really needed here */ |
| 20 | static const struct iommu_ops grant_dma_iommu_ops; |
| 21 | |
| 22 | static const struct of_device_id grant_dma_iommu_of_match[] = { |
| 23 | { .compatible = "xen,grant-dma" }, |
| 24 | { }, |
| 25 | }; |
| 26 | |
| 27 | static int grant_dma_iommu_probe(struct platform_device *pdev) |
| 28 | { |
| 29 | struct grant_dma_iommu_device *mmu; |
| 30 | int ret; |
| 31 | |
| 32 | mmu = devm_kzalloc(&pdev->dev, sizeof(*mmu), GFP_KERNEL); |
| 33 | if (!mmu) |
| 34 | return -ENOMEM; |
| 35 | |
| 36 | mmu->dev = &pdev->dev; |
| 37 | |
| 38 | ret = iommu_device_register(&mmu->iommu, &grant_dma_iommu_ops, &pdev->dev); |
| 39 | if (ret) |
| 40 | return ret; |
| 41 | |
| 42 | platform_set_drvdata(pdev, mmu); |
| 43 | |
| 44 | return 0; |
| 45 | } |
| 46 | |
| 47 | static int grant_dma_iommu_remove(struct platform_device *pdev) |
| 48 | { |
| 49 | struct grant_dma_iommu_device *mmu = platform_get_drvdata(pdev); |
| 50 | |
| 51 | platform_set_drvdata(pdev, NULL); |
| 52 | iommu_device_unregister(&mmu->iommu); |
| 53 | |
| 54 | return 0; |
| 55 | } |
| 56 | |
| 57 | static struct platform_driver grant_dma_iommu_driver = { |
| 58 | .driver = { |
| 59 | .name = "grant-dma-iommu", |
| 60 | .of_match_table = grant_dma_iommu_of_match, |
| 61 | }, |
| 62 | .probe = grant_dma_iommu_probe, |
| 63 | .remove = grant_dma_iommu_remove, |
| 64 | }; |
| 65 | |
| 66 | static int __init grant_dma_iommu_init(void) |
| 67 | { |
| 68 | struct device_node *iommu_np; |
| 69 | |
| 70 | iommu_np = of_find_matching_node(NULL, grant_dma_iommu_of_match); |
| 71 | if (!iommu_np) |
| 72 | return 0; |
| 73 | |
| 74 | of_node_put(iommu_np); |
| 75 | |
| 76 | return platform_driver_register(&grant_dma_iommu_driver); |
| 77 | } |
| 78 | subsys_initcall(grant_dma_iommu_init); |