86 lines
1.9 KiB
C
86 lines
1.9 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
/*
|
|
* Stub IOMMU driver which does nothing.
|
|
* The main purpose of it being present is to reuse generic IOMMU device tree
|
|
* bindings by Xen grant DMA-mapping layer.
|
|
*
|
|
* Copyright (C) 2022 EPAM Systems Inc.
|
|
*/
|
|
|
|
#include <linux/iommu.h>
|
|
#include <linux/of.h>
|
|
#include <linux/platform_device.h>
|
|
|
|
struct grant_dma_iommu_device {
|
|
struct device *dev;
|
|
struct iommu_device iommu;
|
|
};
|
|
|
|
static struct iommu_device *grant_dma_iommu_probe_device(struct device *dev)
|
|
{
|
|
return ERR_PTR(-ENODEV);
|
|
}
|
|
|
|
/* Nothing is really needed here except a dummy probe_device callback */
|
|
static const struct iommu_ops grant_dma_iommu_ops = {
|
|
.probe_device = grant_dma_iommu_probe_device,
|
|
};
|
|
|
|
static const struct of_device_id grant_dma_iommu_of_match[] = {
|
|
{ .compatible = "xen,grant-dma" },
|
|
{ },
|
|
};
|
|
|
|
static int grant_dma_iommu_probe(struct platform_device *pdev)
|
|
{
|
|
struct grant_dma_iommu_device *mmu;
|
|
int ret;
|
|
|
|
mmu = devm_kzalloc(&pdev->dev, sizeof(*mmu), GFP_KERNEL);
|
|
if (!mmu)
|
|
return -ENOMEM;
|
|
|
|
mmu->dev = &pdev->dev;
|
|
|
|
ret = iommu_device_register(&mmu->iommu, &grant_dma_iommu_ops, &pdev->dev);
|
|
if (ret)
|
|
return ret;
|
|
|
|
platform_set_drvdata(pdev, mmu);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int grant_dma_iommu_remove(struct platform_device *pdev)
|
|
{
|
|
struct grant_dma_iommu_device *mmu = platform_get_drvdata(pdev);
|
|
|
|
platform_set_drvdata(pdev, NULL);
|
|
iommu_device_unregister(&mmu->iommu);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static struct platform_driver grant_dma_iommu_driver = {
|
|
.driver = {
|
|
.name = "grant-dma-iommu",
|
|
.of_match_table = grant_dma_iommu_of_match,
|
|
},
|
|
.probe = grant_dma_iommu_probe,
|
|
.remove = grant_dma_iommu_remove,
|
|
};
|
|
|
|
static int __init grant_dma_iommu_init(void)
|
|
{
|
|
struct device_node *iommu_np;
|
|
|
|
iommu_np = of_find_matching_node(NULL, grant_dma_iommu_of_match);
|
|
if (!iommu_np)
|
|
return 0;
|
|
|
|
of_node_put(iommu_np);
|
|
|
|
return platform_driver_register(&grant_dma_iommu_driver);
|
|
}
|
|
subsys_initcall(grant_dma_iommu_init);
|