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// SPDX-License-Identifier: GPL-2.0-only
/*
* vDPA bus.
*
* Copyright (c) 2020, Red Hat. All rights reserved.
* Author: Jason Wang <jasowang@redhat.com>
*
*/
#include <linux/module.h>
#include <linux/idr.h>
#include <linux/slab.h>
#include <linux/vdpa.h>
/* A global mutex that protects vdpa management device and device level operations. */
static DEFINE_MUTEX(vdpa_dev_mutex);
static DEFINE_IDA(vdpa_index_ida);
static int vdpa_dev_probe(struct device *d)
{
struct vdpa_device *vdev = dev_to_vdpa(d);
struct vdpa_driver *drv = drv_to_vdpa(vdev->dev.driver);
int ret = 0;
if (drv && drv->probe)
ret = drv->probe(vdev);
return ret;
}
static int vdpa_dev_remove(struct device *d)
{
struct vdpa_device *vdev = dev_to_vdpa(d);
struct vdpa_driver *drv = drv_to_vdpa(vdev->dev.driver);
if (drv && drv->remove)
drv->remove(vdev);
return 0;
}
static struct bus_type vdpa_bus = {
.name = "vdpa",
.probe = vdpa_dev_probe,
.remove = vdpa_dev_remove,
};
static void vdpa_release_dev(struct device *d)
{
struct vdpa_device *vdev = dev_to_vdpa(d);
const struct vdpa_config_ops *ops = vdev->config;
if (ops->free)
ops->free(vdev);
ida_simple_remove(&vdpa_index_ida, vdev->index);
kfree(vdev);
}
/**
* __vdpa_alloc_device - allocate and initilaize a vDPA device
* This allows driver to some prepartion after device is
* initialized but before registered.
* @parent: the parent device
* @config: the bus operations that is supported by this device
* @nvqs: number of virtqueues supported by this device
* @size: size of the parent structure that contains private data
* @name: name of the vdpa device; optional.
*
* Driver should use vdpa_alloc_device() wrapper macro instead of
* using this directly.
*
* Returns an error when parent/config/dma_dev is not set or fail to get
* ida.
*/
struct vdpa_device *__vdpa_alloc_device(struct device *parent,
const struct vdpa_config_ops *config,
int nvqs, size_t size, const char *name)
{
struct vdpa_device *vdev;
int err = -EINVAL;
if (!config)
goto err;
if (!!config->dma_map != !!config->dma_unmap)
goto err;
err = -ENOMEM;
vdev = kzalloc(size, GFP_KERNEL);
if (!vdev)
goto err;
err = ida_alloc(&vdpa_index_ida, GFP_KERNEL);
if (err < 0)
goto err_ida;
vdev->dev.bus = &vdpa_bus;
vdev->dev.parent = parent;
vdev->dev.release = vdpa_release_dev;
vdev->index = err;
vdev->config = config;
vdev->features_valid = false;
vdev->nvqs = nvqs;
if (name)
err = dev_set_name(&vdev->dev, "%s", name);
else
err = dev_set_name(&vdev->dev, "vdpa%u", vdev->index);
if (err)
goto err_name;
device_initialize(&vdev->dev);
return vdev;
err_name:
ida_simple_remove(&vdpa_index_ida, vdev->index);
err_ida:
kfree(vdev);
err:
return ERR_PTR(err);
}
EXPORT_SYMBOL_GPL(__vdpa_alloc_device);
static int vdpa_name_match(struct device *dev, const void *data)
{
struct vdpa_device *vdev = container_of(dev, struct vdpa_device, dev);
return (strcmp(dev_name(&vdev->dev), data) == 0);
}
/**
* vdpa_register_device - register a vDPA device
* Callers must have a succeed call of vdpa_alloc_device() before.
* @vdev: the vdpa device to be registered to vDPA bus
*
* Returns an error when fail to add to vDPA bus
*/
int vdpa_register_device(struct vdpa_device *vdev)
{
struct device *dev;
int err;
mutex_lock(&vdpa_dev_mutex);
dev = bus_find_device(&vdpa_bus, NULL, dev_name(&vdev->dev), vdpa_name_match);
if (dev) {
put_device(dev);
err = -EEXIST;
goto name_err;
}
err = device_add(&vdev->dev);
name_err:
mutex_unlock(&vdpa_dev_mutex);
return err;
}
EXPORT_SYMBOL_GPL(vdpa_register_device);
/**
* vdpa_unregister_device - unregister a vDPA device
* @vdev: the vdpa device to be unregisted from vDPA bus
*/
void vdpa_unregister_device(struct vdpa_device *vdev)
{
mutex_lock(&vdpa_dev_mutex);
device_unregister(&vdev->dev);
mutex_unlock(&vdpa_dev_mutex);
}
EXPORT_SYMBOL_GPL(vdpa_unregister_device);
/**
* __vdpa_register_driver - register a vDPA device driver
* @drv: the vdpa device driver to be registered
* @owner: module owner of the driver
*
* Returns an err when fail to do the registration
*/
int __vdpa_register_driver(struct vdpa_driver *drv, struct module *owner)
{
drv->driver.bus = &vdpa_bus;
drv->driver.owner = owner;
return driver_register(&drv->driver);
}
EXPORT_SYMBOL_GPL(__vdpa_register_driver);
/**
* vdpa_unregister_driver - unregister a vDPA device driver
* @drv: the vdpa device driver to be unregistered
*/
void vdpa_unregister_driver(struct vdpa_driver *drv)
{
driver_unregister(&drv->driver);
}
EXPORT_SYMBOL_GPL(vdpa_unregister_driver);
static int vdpa_init(void)
{
return bus_register(&vdpa_bus);
}
static void __exit vdpa_exit(void)
{
bus_unregister(&vdpa_bus);
ida_destroy(&vdpa_index_ida);
}
core_initcall(vdpa_init);
module_exit(vdpa_exit);
MODULE_AUTHOR("Jason Wang <jasowang@redhat.com>");
MODULE_LICENSE("GPL v2");
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