Commit 21083f51 authored by Dan Williams's avatar Dan Williams
Browse files

cxl/pmem: Register 'pmem' / cxl_nvdimm devices 



While a memX device on /sys/bus/cxl represents a CXL memory expander
control interface, a pmemX device represents the persistent memory
sub-functionality. It bridges the CXL subystem to the libnvdimm nmemX
control interface.

With this skeleton ndctl can now see persistent memory devices on a
"CXL" bus. Later patches add support for translating libnvdimm native
commands to CXL commands.

# ndctl list -BDiu -b CXL
{
  "provider":"CXL",
  "dev":"ndbus1",
  "dimms":[
    {
      "dev":"nmem1",
      "state":"disabled"
    },
    {
      "dev":"nmem0",
      "state":"disabled"
    }
  ]
}

Given nvdimm_bus_unregister() removes all devices on an ndbus0 the
cxl_pmem infrastructure needs to arrange ->remove() to be triggered on
cxl_nvdimm devices to keep their enabled state synchronized with the
registration state of their corresponding device on the nvdimm_bus. In
other words, always arrange for cxl_nvdimm_driver.remove() to unregister
nvdimms from an nvdimm_bus ahead of the bus being unregistered.

Reviewed-by: default avatarJonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/162380012696.3039556.4293801691038740850.stgit@dwillia2-desk3.amr.corp.intel.com


Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
parent 2bbafda4

drivers/cxl/core.c

+86 −0
Original line number Diff line number Diff line
@@ -7,6 +7,7 @@ 
#include <linux/slab.h>

#include <linux/idr.h>

#include "cxl.h"

#include "mem.h"



/**

 * DOC: cxl core
@@ -730,6 +731,89 @@ struct cxl_nvdimm_bridge *devm_cxl_add_nvdimm_bridge(struct device *host, 
}

EXPORT_SYMBOL_GPL(devm_cxl_add_nvdimm_bridge);



static void cxl_nvdimm_release(struct device *dev)

{

	struct cxl_nvdimm *cxl_nvd = to_cxl_nvdimm(dev);



	kfree(cxl_nvd);

}



static const struct attribute_group *cxl_nvdimm_attribute_groups[] = {

	&cxl_base_attribute_group,

	NULL,

};



static const struct device_type cxl_nvdimm_type = {

	.name = "cxl_nvdimm",

	.release = cxl_nvdimm_release,

	.groups = cxl_nvdimm_attribute_groups,

};



bool is_cxl_nvdimm(struct device *dev)

{

	return dev->type == &cxl_nvdimm_type;

}

EXPORT_SYMBOL_GPL(is_cxl_nvdimm);



struct cxl_nvdimm *to_cxl_nvdimm(struct device *dev)

{

	if (dev_WARN_ONCE(dev, !is_cxl_nvdimm(dev),

			  "not a cxl_nvdimm device\n"))

		return NULL;

	return container_of(dev, struct cxl_nvdimm, dev);

}

EXPORT_SYMBOL_GPL(to_cxl_nvdimm);



static struct cxl_nvdimm *cxl_nvdimm_alloc(struct cxl_memdev *cxlmd)

{

	struct cxl_nvdimm *cxl_nvd;

	struct device *dev;



	cxl_nvd = kzalloc(sizeof(*cxl_nvd), GFP_KERNEL);

	if (!cxl_nvd)

		return ERR_PTR(-ENOMEM);



	dev = &cxl_nvd->dev;

	cxl_nvd->cxlmd = cxlmd;

	device_initialize(dev);

	device_set_pm_not_required(dev);

	dev->parent = &cxlmd->dev;

	dev->bus = &cxl_bus_type;

	dev->type = &cxl_nvdimm_type;



	return cxl_nvd;

}



int devm_cxl_add_nvdimm(struct device *host, struct cxl_memdev *cxlmd)

{

	struct cxl_nvdimm *cxl_nvd;

	struct device *dev;

	int rc;



	cxl_nvd = cxl_nvdimm_alloc(cxlmd);

	if (IS_ERR(cxl_nvd))

		return PTR_ERR(cxl_nvd);



	dev = &cxl_nvd->dev;

	rc = dev_set_name(dev, "pmem%d", cxlmd->id);

	if (rc)

		goto err;



	rc = device_add(dev);

	if (rc)

		goto err;



	dev_dbg(host, "%s: register %s\n", dev_name(dev->parent),

		dev_name(dev));



	return devm_add_action_or_reset(host, unregister_dev, dev);



err:

	put_device(dev);

	return rc;

}

EXPORT_SYMBOL_GPL(devm_cxl_add_nvdimm);



/**

 * cxl_probe_device_regs() - Detect CXL Device register blocks

 * @dev: Host device of the @base mapping
@@ -929,6 +1013,8 @@ static int cxl_device_id(struct device *dev) 
{

	if (dev->type == &cxl_nvdimm_bridge_type)

		return CXL_DEVICE_NVDIMM_BRIDGE;

	if (dev->type == &cxl_nvdimm_type)

		return CXL_DEVICE_NVDIMM;

	return 0;

}

drivers/cxl/cxl.h

+11 −1
Original line number Diff line number Diff line
@@ -220,6 +220,12 @@ struct cxl_nvdimm_bridge { 
	enum cxl_nvdimm_brige_state state;

};



struct cxl_nvdimm {

	struct device dev;

	struct cxl_memdev *cxlmd;

	struct nvdimm *nvdimm;

};



/**

 * struct cxl_port - logical collection of upstream port devices and

 *		     downstream port devices to construct a CXL memory
@@ -307,6 +313,7 @@ int __cxl_driver_register(struct cxl_driver *cxl_drv, struct module *owner, 
void cxl_driver_unregister(struct cxl_driver *cxl_drv);



#define CXL_DEVICE_NVDIMM_BRIDGE	1

#define CXL_DEVICE_NVDIMM		2



#define MODULE_ALIAS_CXL(type) MODULE_ALIAS("cxl:t" __stringify(type) "*")

#define CXL_MODALIAS_FMT "cxl:t%d"
@@ -314,4 +321,7 @@ void cxl_driver_unregister(struct cxl_driver *cxl_drv); 
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);

struct cxl_nvdimm *to_cxl_nvdimm(struct device *dev);

bool is_cxl_nvdimm(struct device *dev);

int devm_cxl_add_nvdimm(struct device *host, struct cxl_memdev *cxlmd);

#endif /* __CXL_H__ */

drivers/cxl/mem.h

+2 −0
Original line number Diff line number Diff line
@@ -2,6 +2,8 @@ 
/* Copyright(c) 2020-2021 Intel Corporation. */

#ifndef __CXL_MEM_H__

#define __CXL_MEM_H__

#include <linux/cdev.h>

#include "cxl.h"



/* CXL 2.0 8.2.8.5.1.1 Memory Device Status Register */

#define CXLMDEV_STATUS_OFFSET 0x0

drivers/cxl/pci.c

+17 −6
Original line number Diff line number Diff line
@@ -1332,7 +1332,8 @@ static struct cxl_memdev *cxl_memdev_alloc(struct cxl_mem *cxlm) 
	return ERR_PTR(rc);

}



static int cxl_mem_add_memdev(struct cxl_mem *cxlm)

static struct cxl_memdev *devm_cxl_add_memdev(struct device *host,

					      struct cxl_mem *cxlm)

{

	struct cxl_memdev *cxlmd;

	struct device *dev;
@@ -1341,7 +1342,7 @@ static int cxl_mem_add_memdev(struct cxl_mem *cxlm) 


	cxlmd = cxl_memdev_alloc(cxlm);

	if (IS_ERR(cxlmd))

		return PTR_ERR(cxlmd);

		return cxlmd;



	dev = &cxlmd->dev;

	rc = dev_set_name(dev, "mem%d", cxlmd->id);
@@ -1359,8 +1360,10 @@ static int cxl_mem_add_memdev(struct cxl_mem *cxlm) 
	if (rc)

		goto err;



	return devm_add_action_or_reset(dev->parent, cxl_memdev_unregister,

					cxlmd);

	rc = devm_add_action_or_reset(host, cxl_memdev_unregister, cxlmd);

	if (rc)

		return ERR_PTR(rc);

	return cxlmd;



err:

	/*
@@ -1369,7 +1372,7 @@ static int cxl_mem_add_memdev(struct cxl_mem *cxlm) 
	 */

	cxl_memdev_shutdown(cxlmd);

	put_device(dev);

	return rc;

	return ERR_PTR(rc);

}



static int cxl_xfer_log(struct cxl_mem *cxlm, uuid_t *uuid, u32 size, u8 *out)
@@ -1580,6 +1583,7 @@ static int cxl_mem_identify(struct cxl_mem *cxlm) 


static int cxl_mem_probe(struct pci_dev *pdev, const struct pci_device_id *id)

{

	struct cxl_memdev *cxlmd;

	struct cxl_mem *cxlm;

	int rc;
@@ -1607,7 +1611,14 @@ static int cxl_mem_probe(struct pci_dev *pdev, const struct pci_device_id *id) 
	if (rc)

		return rc;



	return cxl_mem_add_memdev(cxlm);

	cxlmd = devm_cxl_add_memdev(&pdev->dev, cxlm);

	if (IS_ERR(cxlmd))

		return PTR_ERR(cxlmd);



	if (range_len(&cxlm->pmem_range) && IS_ENABLED(CONFIG_CXL_PMEM))

		rc = devm_cxl_add_nvdimm(&pdev->dev, cxlmd);



	return rc;

}



static const struct pci_device_id cxl_mem_pci_tbl[] = {

drivers/cxl/pmem.c

+99 −9
Original line number Diff line number Diff line
@@ -3,7 +3,10 @@ 
#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"



/*
@@ -13,6 +16,62 @@ 
 */

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)
@@ -29,19 +88,34 @@ static bool online_nvdimm_bus(struct cxl_nvdimm_bridge *cxl_nvb) 
	return cxl_nvb->nvdimm_bus != NULL;

}



static void offline_nvdimm_bus(struct cxl_nvdimm_bridge *cxl_nvb)

static int cxl_nvdimm_release_driver(struct device *dev, void *data)

{

	if (!cxl_nvb->nvdimm_bus)

	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;

	nvdimm_bus_unregister(cxl_nvb->nvdimm_bus);

	cxl_nvb->nvdimm_bus = NULL;



	/*

	 * 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);

	bool release = false;

	struct nvdimm_bus *victim_bus = NULL;

	bool release = false, rescan = false;



	device_lock(&cxl_nvb->dev);

	switch (cxl_nvb->state) {
@@ -50,11 +124,13 @@ static void cxl_nvb_update_state(struct work_struct *work) 
			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:

		offline_nvdimm_bus(cxl_nvb);

		victim_bus = cxl_nvb->nvdimm_bus;

		cxl_nvb->nvdimm_bus = NULL;

		break;

	default:

		break;
@@ -63,6 +139,12 @@ static void cxl_nvb_update_state(struct work_struct *work) 


	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);

}
@@ -118,17 +200,24 @@ static __init int cxl_pmem_init(void) 


	rc = cxl_driver_register(&cxl_nvdimm_bridge_driver);

	if (rc)

		goto err;

		goto err_bridge;



	rc = cxl_driver_register(&cxl_nvdimm_driver);

	if (rc)

		goto err_nvdimm;



	return 0;



err:

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);

}
@@ -138,3 +227,4 @@ 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);