diff options
Diffstat (limited to 'drivers/cxl/pmem.c')
| -rw-r--r-- | drivers/cxl/pmem.c | 230 |
1 files changed, 230 insertions, 0 deletions
diff --git a/drivers/cxl/pmem.c b/drivers/cxl/pmem.c new file mode 100644 index 000000000000..0088e41dd2f3 --- /dev/null +++ b/drivers/cxl/pmem.c @@ -0,0 +1,230 @@ +// 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 "mem.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); |