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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/ndctl.h>
#include <linux/async.h>
#include <linux/slab.h>
#include "cxlmem.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 void unregister_nvdimm(void *nvdimm)
{
nvdimm_delete(nvdimm);
}
static int match_nvdimm_bridge(struct device *dev, const void *data)
{
return strcmp(dev_name(dev), "nvdimm-bridge") == 0;
}
static struct cxl_nvdimm_bridge *cxl_find_nvdimm_bridge(void)
{
struct device *dev;
dev = bus_find_device(&cxl_bus_type, NULL, NULL, match_nvdimm_bridge);
if (!dev)
return NULL;
return to_cxl_nvdimm_bridge(dev);
}
static int cxl_nvdimm_probe(struct device *dev)
{
struct cxl_nvdimm *cxl_nvd = to_cxl_nvdimm(dev);
struct cxl_nvdimm_bridge *cxl_nvb;
unsigned long flags = 0;
struct nvdimm *nvdimm;
int rc = -ENXIO;
cxl_nvb = cxl_find_nvdimm_bridge();
if (!cxl_nvb)
return -ENXIO;
device_lock(&cxl_nvb->dev);
if (!cxl_nvb->nvdimm_bus)
goto out;
set_bit(NDD_LABELING, &flags);
nvdimm = nvdimm_create(cxl_nvb->nvdimm_bus, cxl_nvd, NULL, flags, 0, 0,
NULL);
if (!nvdimm)
goto out;
rc = devm_add_action_or_reset(dev, unregister_nvdimm, nvdimm);
out:
device_unlock(&cxl_nvb->dev);
put_device(&cxl_nvb->dev);
return rc;
}
static struct cxl_driver cxl_nvdimm_driver = {
.name = "cxl_nvdimm",
.probe = cxl_nvdimm_probe,
.id = CXL_DEVICE_NVDIMM,
};
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 int cxl_nvdimm_release_driver(struct device *dev, void *data)
{
if (!is_cxl_nvdimm(dev))
return 0;
device_release_driver(dev);
return 0;
}
static void offline_nvdimm_bus(struct nvdimm_bus *nvdimm_bus)
{
if (!nvdimm_bus)
return;
/*
* Set the state of cxl_nvdimm devices to unbound / idle before
* nvdimm_bus_unregister() rips the nvdimm objects out from
* underneath them.
*/
bus_for_each_dev(&cxl_bus_type, NULL, NULL, cxl_nvdimm_release_driver);
nvdimm_bus_unregister(nvdimm_bus);
}
static void cxl_nvb_update_state(struct work_struct *work)
{
struct cxl_nvdimm_bridge *cxl_nvb =
container_of(work, typeof(*cxl_nvb), state_work);
struct nvdimm_bus *victim_bus = NULL;
bool release = false, rescan = 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;
} else
rescan = true;
break;
case CXL_NVB_OFFLINE:
case CXL_NVB_DEAD:
victim_bus = cxl_nvb->nvdimm_bus;
cxl_nvb->nvdimm_bus = NULL;
break;
default:
break;
}
device_unlock(&cxl_nvb->dev);
if (release)
device_release_driver(&cxl_nvb->dev);
if (rescan) {
int rc = bus_rescan_devices(&cxl_bus_type);
dev_dbg(&cxl_nvb->dev, "rescan: %d\n", rc);
}
offline_nvdimm_bus(victim_bus);
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_bridge;
rc = cxl_driver_register(&cxl_nvdimm_driver);
if (rc)
goto err_nvdimm;
return 0;
err_nvdimm:
cxl_driver_unregister(&cxl_nvdimm_bridge_driver);
err_bridge:
destroy_workqueue(cxl_pmem_wq);
return rc;
}
static __exit void cxl_pmem_exit(void)
{
cxl_driver_unregister(&cxl_nvdimm_driver);
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);
MODULE_ALIAS_CXL(CXL_DEVICE_NVDIMM);
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