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// SPDX-License-Identifier: GPL-2.0-only
/*
* Intel MIC Platform Software Stack (MPSS)
*
* Copyright(c) 2014 Intel Corporation.
*
* Intel SCIF driver.
*/
#include "scif_main.h"
#include "../bus/scif_bus.h"
#include "scif_peer_bus.h"
static inline struct scif_peer_dev *
dev_to_scif_peer(struct device *dev)
{
return container_of(dev, struct scif_peer_dev, dev);
}
struct bus_type scif_peer_bus = {
.name = "scif_peer_bus",
};
static void scif_peer_release_dev(struct device *d)
{
struct scif_peer_dev *sdev = dev_to_scif_peer(d);
struct scif_dev *scifdev = &scif_dev[sdev->dnode];
scif_cleanup_scifdev(scifdev);
kfree(sdev);
}
static int scif_peer_initialize_device(struct scif_dev *scifdev)
{
struct scif_peer_dev *spdev;
int ret;
spdev = kzalloc(sizeof(*spdev), GFP_KERNEL);
if (!spdev) {
ret = -ENOMEM;
goto err;
}
spdev->dev.parent = scifdev->sdev->dev.parent;
spdev->dev.release = scif_peer_release_dev;
spdev->dnode = scifdev->node;
spdev->dev.bus = &scif_peer_bus;
dev_set_name(&spdev->dev, "scif_peer-dev%u", spdev->dnode);
device_initialize(&spdev->dev);
get_device(&spdev->dev);
rcu_assign_pointer(scifdev->spdev, spdev);
mutex_lock(&scif_info.conflock);
scif_info.total++;
scif_info.maxid = max_t(u32, spdev->dnode, scif_info.maxid);
mutex_unlock(&scif_info.conflock);
return 0;
err:
dev_err(&scifdev->sdev->dev,
"dnode %d: initialize_device rc %d\n", scifdev->node, ret);
return ret;
}
static int scif_peer_add_device(struct scif_dev *scifdev)
{
struct scif_peer_dev *spdev = rcu_dereference(scifdev->spdev);
char pool_name[16];
int ret;
ret = device_add(&spdev->dev);
put_device(&spdev->dev);
if (ret) {
dev_err(&scifdev->sdev->dev,
"dnode %d: peer device_add failed\n", scifdev->node);
goto put_spdev;
}
scnprintf(pool_name, sizeof(pool_name), "scif-%d", spdev->dnode);
scifdev->signal_pool = dmam_pool_create(pool_name, &scifdev->sdev->dev,
sizeof(struct scif_status), 1,
0);
if (!scifdev->signal_pool) {
dev_err(&scifdev->sdev->dev,
"dnode %d: dmam_pool_create failed\n", scifdev->node);
ret = -ENOMEM;
goto del_spdev;
}
dev_dbg(&spdev->dev, "Added peer dnode %d\n", spdev->dnode);
return 0;
del_spdev:
device_del(&spdev->dev);
put_spdev:
RCU_INIT_POINTER(scifdev->spdev, NULL);
synchronize_rcu();
put_device(&spdev->dev);
mutex_lock(&scif_info.conflock);
scif_info.total--;
mutex_unlock(&scif_info.conflock);
return ret;
}
void scif_add_peer_device(struct work_struct *work)
{
struct scif_dev *scifdev = container_of(work, struct scif_dev,
peer_add_work);
scif_peer_add_device(scifdev);
}
/*
* Peer device registration is split into a device_initialize and a device_add.
* The reason for doing this is as follows: First, peer device registration
* itself cannot be done in the message processing thread and must be delegated
* to another workqueue, otherwise if SCIF client probe, called during peer
* device registration, calls scif_connect(..), it will block the message
* processing thread causing a deadlock. Next, device_initialize is done in the
* "top-half" message processing thread and device_add in the "bottom-half"
* workqueue. If this is not done, SCIF_CNCT_REQ message processing executing
* concurrently with SCIF_INIT message processing is unable to get a reference
* on the peer device, thereby failing the connect request.
*/
void scif_peer_register_device(struct scif_dev *scifdev)
{
int ret;
mutex_lock(&scifdev->lock);
ret = scif_peer_initialize_device(scifdev);
if (ret)
goto exit;
schedule_work(&scifdev->peer_add_work);
exit:
mutex_unlock(&scifdev->lock);
}
int scif_peer_unregister_device(struct scif_dev *scifdev)
{
struct scif_peer_dev *spdev;
mutex_lock(&scifdev->lock);
/* Flush work to ensure device register is complete */
flush_work(&scifdev->peer_add_work);
/*
* Continue holding scifdev->lock since theoretically unregister_device
* can be called simultaneously from multiple threads
*/
spdev = rcu_dereference(scifdev->spdev);
if (!spdev) {
mutex_unlock(&scifdev->lock);
return -ENODEV;
}
RCU_INIT_POINTER(scifdev->spdev, NULL);
synchronize_rcu();
mutex_unlock(&scifdev->lock);
dev_dbg(&spdev->dev, "Removing peer dnode %d\n", spdev->dnode);
device_unregister(&spdev->dev);
mutex_lock(&scif_info.conflock);
scif_info.total--;
mutex_unlock(&scif_info.conflock);
return 0;
}
int scif_peer_bus_init(void)
{
return bus_register(&scif_peer_bus);
}
void scif_peer_bus_exit(void)
{
bus_unregister(&scif_peer_bus);
}
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