hierarchy to map regions that represent System RAM, or Persistent
Memory regions to be managed by LIBNVDIMM.
+ If unsure say 'm'.
+
+config CXL_PMEM
+ tristate "CXL PMEM: Persistent Memory Support"
+ depends on LIBNVDIMM
+ default CXL_BUS
+ help
+ In addition to typical memory resources a platform may also advertise
+ support for persistent memory attached via CXL. This support is
+ managed via a bridge driver from CXL to the LIBNVDIMM system
+ subsystem. Say 'y/m' to enable support for enumerating and
+ provisioning the persistent memory capacity of CXL memory expanders.
+
If unsure say 'm'.
endif
obj-$(CONFIG_CXL_BUS) += cxl_core.o
obj-$(CONFIG_CXL_MEM) += cxl_pci.o
obj-$(CONFIG_CXL_ACPI) += cxl_acpi.o
+obj-$(CONFIG_CXL_PMEM) += cxl_pmem.o
ccflags-y += -DDEFAULT_SYMBOL_NAMESPACE=CXL
cxl_core-y := core.o
cxl_pci-y := pci.o
cxl_acpi-y := acpi.o
+cxl_pmem-y := pmem.o
return 0;
}
+static int add_root_nvdimm_bridge(struct device *match, void *data)
+{
+ struct cxl_decoder *cxld;
+ struct cxl_port *root_port = data;
+ struct cxl_nvdimm_bridge *cxl_nvb;
+ struct device *host = root_port->dev.parent;
+
+ if (!is_root_decoder(match))
+ return 0;
+
+ cxld = to_cxl_decoder(match);
+ if (!(cxld->flags & CXL_DECODER_F_PMEM))
+ return 0;
+
+ cxl_nvb = devm_cxl_add_nvdimm_bridge(host, root_port);
+ if (IS_ERR(cxl_nvb)) {
+ dev_dbg(host, "failed to register pmem\n");
+ return PTR_ERR(cxl_nvb);
+ }
+ dev_dbg(host, "%s: add: %s\n", dev_name(&root_port->dev),
+ dev_name(&cxl_nvb->dev));
+ return 1;
+}
+
static int cxl_acpi_probe(struct platform_device *pdev)
{
int rc;
* Root level scanned with host-bridge as dports, now scan host-bridges
* for their role as CXL uports to their CXL-capable PCIe Root Ports.
*/
- return bus_for_each_dev(adev->dev.bus, NULL, root_port,
- add_host_bridge_uport);
+ rc = bus_for_each_dev(adev->dev.bus, NULL, root_port,
+ add_host_bridge_uport);
+ if (rc)
+ return rc;
+
+ if (IS_ENABLED(CONFIG_CXL_PMEM))
+ rc = device_for_each_child(&root_port->dev, root_port,
+ add_root_nvdimm_bridge);
+ if (rc < 0)
+ return rc;
+ return 0;
}
static const struct acpi_device_id cxl_acpi_ids[] = {
.groups = cxl_decoder_root_attribute_groups,
};
+bool is_root_decoder(struct device *dev)
+{
+ return dev->type == &cxl_decoder_root_type;
+}
+EXPORT_SYMBOL_GPL(is_root_decoder);
+
struct cxl_decoder *to_cxl_decoder(struct device *dev)
{
if (dev_WARN_ONCE(dev, dev->type->release != cxl_decoder_release,
return NULL;
return container_of(dev, struct cxl_decoder, dev);
}
+EXPORT_SYMBOL_GPL(to_cxl_decoder);
static void cxl_dport_release(struct cxl_dport *dport)
{
}
EXPORT_SYMBOL_GPL(cxl_probe_component_regs);
+static void cxl_nvdimm_bridge_release(struct device *dev)
+{
+ struct cxl_nvdimm_bridge *cxl_nvb = to_cxl_nvdimm_bridge(dev);
+
+ kfree(cxl_nvb);
+}
+
+static const struct attribute_group *cxl_nvdimm_bridge_attribute_groups[] = {
+ &cxl_base_attribute_group,
+ NULL,
+};
+
+static const struct device_type cxl_nvdimm_bridge_type = {
+ .name = "cxl_nvdimm_bridge",
+ .release = cxl_nvdimm_bridge_release,
+ .groups = cxl_nvdimm_bridge_attribute_groups,
+};
+
+struct cxl_nvdimm_bridge *to_cxl_nvdimm_bridge(struct device *dev)
+{
+ if (dev_WARN_ONCE(dev, dev->type != &cxl_nvdimm_bridge_type,
+ "not a cxl_nvdimm_bridge device\n"))
+ return NULL;
+ return container_of(dev, struct cxl_nvdimm_bridge, dev);
+}
+EXPORT_SYMBOL_GPL(to_cxl_nvdimm_bridge);
+
+static struct cxl_nvdimm_bridge *
+cxl_nvdimm_bridge_alloc(struct cxl_port *port)
+{
+ struct cxl_nvdimm_bridge *cxl_nvb;
+ struct device *dev;
+
+ cxl_nvb = kzalloc(sizeof(*cxl_nvb), GFP_KERNEL);
+ if (!cxl_nvb)
+ return ERR_PTR(-ENOMEM);
+
+ dev = &cxl_nvb->dev;
+ cxl_nvb->port = port;
+ cxl_nvb->state = CXL_NVB_NEW;
+ device_initialize(dev);
+ device_set_pm_not_required(dev);
+ dev->parent = &port->dev;
+ dev->bus = &cxl_bus_type;
+ dev->type = &cxl_nvdimm_bridge_type;
+
+ return cxl_nvb;
+}
+
+static void unregister_nvb(void *_cxl_nvb)
+{
+ struct cxl_nvdimm_bridge *cxl_nvb = _cxl_nvb;
+ bool flush;
+
+ /*
+ * If the bridge was ever activated then there might be in-flight state
+ * work to flush. Once the state has been changed to 'dead' then no new
+ * work can be queued by user-triggered bind.
+ */
+ device_lock(&cxl_nvb->dev);
+ flush = cxl_nvb->state != CXL_NVB_NEW;
+ cxl_nvb->state = CXL_NVB_DEAD;
+ device_unlock(&cxl_nvb->dev);
+
+ /*
+ * Even though the device core will trigger device_release_driver()
+ * before the unregister, it does not know about the fact that
+ * cxl_nvdimm_bridge_driver defers ->remove() work. So, do the driver
+ * release not and flush it before tearing down the nvdimm device
+ * hierarchy.
+ */
+ device_release_driver(&cxl_nvb->dev);
+ if (flush)
+ flush_work(&cxl_nvb->state_work);
+ device_unregister(&cxl_nvb->dev);
+}
+
+struct cxl_nvdimm_bridge *devm_cxl_add_nvdimm_bridge(struct device *host,
+ struct cxl_port *port)
+{
+ struct cxl_nvdimm_bridge *cxl_nvb;
+ struct device *dev;
+ int rc;
+
+ if (!IS_ENABLED(CONFIG_CXL_PMEM))
+ return ERR_PTR(-ENXIO);
+
+ cxl_nvb = cxl_nvdimm_bridge_alloc(port);
+ if (IS_ERR(cxl_nvb))
+ return cxl_nvb;
+
+ dev = &cxl_nvb->dev;
+ rc = dev_set_name(dev, "nvdimm-bridge");
+ if (rc)
+ goto err;
+
+ rc = device_add(dev);
+ if (rc)
+ goto err;
+
+ rc = devm_add_action_or_reset(host, unregister_nvb, cxl_nvb);
+ if (rc)
+ return ERR_PTR(rc);
+
+ return cxl_nvb;
+
+err:
+ put_device(dev);
+ return ERR_PTR(rc);
+}
+EXPORT_SYMBOL_GPL(devm_cxl_add_nvdimm_bridge);
+
/**
* cxl_probe_device_regs() - Detect CXL Device register blocks
* @dev: Host device of the @base mapping
static int cxl_device_id(struct device *dev)
{
+ if (dev->type == &cxl_nvdimm_bridge_type)
+ return CXL_DEVICE_NVDIMM_BRIDGE;
return 0;
}
#ifndef __CXL_H__
#define __CXL_H__
+#include <linux/libnvdimm.h>
#include <linux/bitfield.h>
#include <linux/bitops.h>
#include <linux/io.h>
struct cxl_dport *target[];
};
+
+enum cxl_nvdimm_brige_state {
+ CXL_NVB_NEW,
+ CXL_NVB_DEAD,
+ CXL_NVB_ONLINE,
+ CXL_NVB_OFFLINE,
+};
+
+struct cxl_nvdimm_bridge {
+ struct device dev;
+ struct cxl_port *port;
+ struct nvdimm_bus *nvdimm_bus;
+ struct nvdimm_bus_descriptor nd_desc;
+ struct work_struct state_work;
+ enum cxl_nvdimm_brige_state state;
+};
+
/**
* struct cxl_port - logical collection of upstream port devices and
* downstream port devices to construct a CXL memory
resource_size_t component_reg_phys);
struct cxl_decoder *to_cxl_decoder(struct device *dev);
+bool is_root_decoder(struct device *dev);
struct cxl_decoder *
devm_cxl_add_decoder(struct device *host, struct cxl_port *port, int nr_targets,
resource_size_t base, resource_size_t len,
#define cxl_driver_register(x) __cxl_driver_register(x, THIS_MODULE, KBUILD_MODNAME)
void cxl_driver_unregister(struct cxl_driver *cxl_drv);
+#define CXL_DEVICE_NVDIMM_BRIDGE 1
+
#define MODULE_ALIAS_CXL(type) MODULE_ALIAS("cxl:t" __stringify(type) "*")
#define CXL_MODALIAS_FMT "cxl:t%d"
+struct cxl_nvdimm_bridge *to_cxl_nvdimm_bridge(struct device *dev);
+struct cxl_nvdimm_bridge *devm_cxl_add_nvdimm_bridge(struct device *host,
+ struct cxl_port *port);
#endif /* __CXL_H__ */
--- /dev/null
+// 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);
projects / thirdparty / linux.git / commitdiff
