134 lines
3 KiB
C
134 lines
3 KiB
C
/*
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* IOMMU sysfs class support
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*
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* Copyright (C) 2014 Red Hat, Inc. All rights reserved.
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* Author: Alex Williamson <alex.williamson@redhat.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/device.h>
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#include <linux/iommu.h>
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#include <linux/module.h>
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#include <linux/slab.h>
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/*
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* We provide a common class "devices" group which initially has no attributes.
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* As devices are added to the IOMMU, we'll add links to the group.
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*/
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static struct attribute *devices_attr[] = {
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NULL,
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};
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static const struct attribute_group iommu_devices_attr_group = {
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.name = "devices",
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.attrs = devices_attr,
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};
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static const struct attribute_group *iommu_dev_groups[] = {
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&iommu_devices_attr_group,
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NULL,
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};
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static void iommu_release_device(struct device *dev)
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{
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kfree(dev);
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}
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static struct class iommu_class = {
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.name = "iommu",
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.dev_release = iommu_release_device,
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.dev_groups = iommu_dev_groups,
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};
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static int __init iommu_dev_init(void)
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{
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return class_register(&iommu_class);
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}
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postcore_initcall(iommu_dev_init);
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/*
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* Create an IOMMU device and return a pointer to it. IOMMU specific
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* attributes can be provided as an attribute group, allowing a unique
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* namespace per IOMMU type.
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*/
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struct device *iommu_device_create(struct device *parent, void *drvdata,
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const struct attribute_group **groups,
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const char *fmt, ...)
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{
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struct device *dev;
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va_list vargs;
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int ret;
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dev = kzalloc(sizeof(*dev), GFP_KERNEL);
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if (!dev)
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return ERR_PTR(-ENOMEM);
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device_initialize(dev);
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dev->class = &iommu_class;
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dev->parent = parent;
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dev->groups = groups;
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dev_set_drvdata(dev, drvdata);
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va_start(vargs, fmt);
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ret = kobject_set_name_vargs(&dev->kobj, fmt, vargs);
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va_end(vargs);
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if (ret)
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goto error;
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ret = device_add(dev);
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if (ret)
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goto error;
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return dev;
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error:
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put_device(dev);
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return ERR_PTR(ret);
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}
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void iommu_device_destroy(struct device *dev)
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{
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if (!dev || IS_ERR(dev))
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return;
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device_unregister(dev);
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}
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/*
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* IOMMU drivers can indicate a device is managed by a given IOMMU using
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* this interface. A link to the device will be created in the "devices"
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* directory of the IOMMU device in sysfs and an "iommu" link will be
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* created under the linked device, pointing back at the IOMMU device.
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*/
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int iommu_device_link(struct device *dev, struct device *link)
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{
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int ret;
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if (!dev || IS_ERR(dev))
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return -ENODEV;
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ret = sysfs_add_link_to_group(&dev->kobj, "devices",
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&link->kobj, dev_name(link));
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if (ret)
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return ret;
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ret = sysfs_create_link_nowarn(&link->kobj, &dev->kobj, "iommu");
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if (ret)
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sysfs_remove_link_from_group(&dev->kobj, "devices",
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dev_name(link));
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return ret;
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}
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void iommu_device_unlink(struct device *dev, struct device *link)
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{
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if (!dev || IS_ERR(dev))
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return;
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sysfs_remove_link(&link->kobj, "iommu");
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sysfs_remove_link_from_group(&dev->kobj, "devices", dev_name(link));
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}
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