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// SPDX-License-Identifier: GPL-2.0-only
/* Copyright(c) 2021 Intel Corporation. All rights reserved. */
#include <linux/libnvdimm.h>
#include <linux/device.h>
#include <linux/module.h>
#include <linux/slab.h>
#include "cxl.h"
/*
* Ordered workqueue for cxl nvdimm device arrival and departure
* to coordinate bus rescans when a bridge arrives and trigger remove
* operations when the bridge is removed.
*/
static struct workqueue_struct *cxl_pmem_wq;
static int cxl_pmem_ctl(struct nvdimm_bus_descriptor *nd_desc,
struct nvdimm *nvdimm, unsigned int cmd, void *buf,
unsigned int buf_len, int *cmd_rc)
{
return -ENOTTY;
}
static bool online_nvdimm_bus(struct cxl_nvdimm_bridge *cxl_nvb)
{
if (cxl_nvb->nvdimm_bus)
return true;
cxl_nvb->nvdimm_bus =
nvdimm_bus_register(&cxl_nvb->dev, &cxl_nvb->nd_desc);
return cxl_nvb->nvdimm_bus != NULL;
}
static void offline_nvdimm_bus(struct cxl_nvdimm_bridge *cxl_nvb)
{
if (!cxl_nvb->nvdimm_bus)
return;
nvdimm_bus_unregister(cxl_nvb->nvdimm_bus);
cxl_nvb->nvdimm_bus = NULL;
}
static void cxl_nvb_update_state(struct work_struct *work)
{
struct cxl_nvdimm_bridge *cxl_nvb =
container_of(work, typeof(*cxl_nvb), state_work);
bool release = false;
device_lock(&cxl_nvb->dev);
switch (cxl_nvb->state) {
case CXL_NVB_ONLINE:
if (!online_nvdimm_bus(cxl_nvb)) {
dev_err(&cxl_nvb->dev,
"failed to establish nvdimm bus\n");
release = true;
}
break;
case CXL_NVB_OFFLINE:
case CXL_NVB_DEAD:
offline_nvdimm_bus(cxl_nvb);
break;
default:
break;
}
device_unlock(&cxl_nvb->dev);
if (release)
device_release_driver(&cxl_nvb->dev);
put_device(&cxl_nvb->dev);
}
static void cxl_nvdimm_bridge_remove(struct device *dev)
{
struct cxl_nvdimm_bridge *cxl_nvb = to_cxl_nvdimm_bridge(dev);
if (cxl_nvb->state == CXL_NVB_ONLINE)
cxl_nvb->state = CXL_NVB_OFFLINE;
if (queue_work(cxl_pmem_wq, &cxl_nvb->state_work))
get_device(&cxl_nvb->dev);
}
static int cxl_nvdimm_bridge_probe(struct device *dev)
{
struct cxl_nvdimm_bridge *cxl_nvb = to_cxl_nvdimm_bridge(dev);
if (cxl_nvb->state == CXL_NVB_DEAD)
return -ENXIO;
if (cxl_nvb->state == CXL_NVB_NEW) {
cxl_nvb->nd_desc = (struct nvdimm_bus_descriptor) {
.provider_name = "CXL",
.module = THIS_MODULE,
.ndctl = cxl_pmem_ctl,
};
INIT_WORK(&cxl_nvb->state_work, cxl_nvb_update_state);
}
cxl_nvb->state = CXL_NVB_ONLINE;
if (queue_work(cxl_pmem_wq, &cxl_nvb->state_work))
get_device(&cxl_nvb->dev);
return 0;
}
static struct cxl_driver cxl_nvdimm_bridge_driver = {
.name = "cxl_nvdimm_bridge",
.probe = cxl_nvdimm_bridge_probe,
.remove = cxl_nvdimm_bridge_remove,
.id = CXL_DEVICE_NVDIMM_BRIDGE,
};
static __init int cxl_pmem_init(void)
{
int rc;
cxl_pmem_wq = alloc_ordered_workqueue("cxl_pmem", 0);
if (!cxl_pmem_wq)
return -ENXIO;
rc = cxl_driver_register(&cxl_nvdimm_bridge_driver);
if (rc)
goto err;
return 0;
err:
destroy_workqueue(cxl_pmem_wq);
return rc;
}
static __exit void cxl_pmem_exit(void)
{
cxl_driver_unregister(&cxl_nvdimm_bridge_driver);
destroy_workqueue(cxl_pmem_wq);
}
MODULE_LICENSE("GPL v2");
module_init(cxl_pmem_init);
module_exit(cxl_pmem_exit);
MODULE_IMPORT_NS(CXL);
MODULE_ALIAS_CXL(CXL_DEVICE_NVDIMM_BRIDGE);
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