blob: 64ccf053d32c37a2608bb96c9e0caa5a58b0c884 [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0-only
/* Copyright(c) 2022 Intel Corporation. All rights reserved. */
#include <linux/debugfs.h>
#include <linux/device.h>
#include <linux/module.h>
#include <linux/pci.h>
#include "cxlmem.h"
#include "cxlpci.h"
* DOC: cxl mem
* CXL memory endpoint devices and switches are CXL capable devices that are
* participating in CXL.mem protocol. Their functionality builds on top of the
* protocol that allows enumerating and configuring components via
* standard PCI mechanisms.
* The cxl_mem driver owns kicking off the enumeration of this CXL.mem
* capability. With the detection of a CXL capable endpoint, the driver will
* walk up to find the platform specific port it is connected to, and determine
* if there are intervening switches in the path. If there are switches, a
* secondary action is to enumerate those (implemented in cxl_core). Finally the
* cxl_mem driver adds the device it is bound to as a CXL endpoint-port for use
* in higher level operations.
static void enable_suspend(void *data)
static void remove_debugfs(void *dentry)
static int cxl_mem_dpa_show(struct seq_file *file, void *data)
struct device *dev = file->private;
struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
cxl_dpa_debug(file, cxlmd->cxlds);
return 0;
static int cxl_mem_probe(struct device *dev)
struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
struct cxl_port *parent_port;
struct cxl_dport *dport;
struct dentry *dentry;
int rc;
* Someone is trying to reattach this device after it lost its port
* connection (an endpoint port previously registered by this memdev was
* disabled). This racy check is ok because if the port is still gone,
* no harm done, and if the port hierarchy comes back it will re-trigger
* this probe. Port rescan and memdev detach work share the same
* single-threaded workqueue.
if (work_pending(&cxlmd->detach_work))
return -EBUSY;
dentry = cxl_debugfs_create_dir(dev_name(dev));
debugfs_create_devm_seqfile(dev, "dpamem", dentry, cxl_mem_dpa_show);
rc = devm_add_action_or_reset(dev, remove_debugfs, dentry);
if (rc)
return rc;
rc = devm_cxl_enumerate_ports(cxlmd);
if (rc)
return rc;
parent_port = cxl_mem_find_port(cxlmd, &dport);
if (!parent_port) {
dev_err(dev, "CXL port topology not found\n");
return -ENXIO;
if (!parent_port->dev.driver) {
dev_err(dev, "CXL port topology %s not enabled\n",
rc = -ENXIO;
goto unlock;
rc = devm_cxl_add_endpoint(cxlmd, dport);
if (rc)
return rc;
* The kernel may be operating out of CXL memory on this device,
* there is no spec defined way to determine whether this device
* preserves contents over suspend, and there is no simple way
* to arrange for the suspend image to avoid CXL memory which
* would setup a circular dependency between PCI resume and save
* state restoration.
* TODO: support suspend when all the regions this device is
* hosting are locked and covered by the system address map,
* i.e. platform firmware owns restoring the HDM configuration
* that it locked.
return devm_add_action_or_reset(dev, enable_suspend, NULL);
static struct cxl_driver cxl_mem_driver = {
.name = "cxl_mem",
.probe = cxl_mem_probe,
* create_endpoint() wants to validate port driver attach immediately after
* endpoint registration.
MODULE_SOFTDEP("pre: cxl_port");