Commit 858ce2f5 authored by Dave Jiang's avatar Dave Jiang Committed by Jason Gunthorpe
Browse files

cxl: Add FWCTL support to CXL 

Add fwctl support code to allow sending of CXL feature commands from
userspace through as ioctls via FWCTL. Provide initial setup bits. The
CXL PCI probe function will call devm_cxl_setup_fwctl() after the
cxl_memdev has been enumerated in order to setup FWCTL char device under
the cxl_memdev like the existing memdev char device for issuing CXL raw
mailbox commands from userspace via ioctls.

Link: https://patch.msgid.link/r/20250307205648.1021626-2-dave.jiang@intel.com


Signed-off-by: default avatarDave Jiang <dave.jiang@intel.com>
Reviewed-by: default avatarLi Ming <ming.li@zohomail.com>
Reviewed-by: default avatarJonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: default avatarJason Gunthorpe <jgg@nvidia.com>
parent 15a26c22

drivers/cxl/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -7,6 +7,7 @@ menuconfig CXL_BUS 
	select PCI_DOE

	select FIRMWARE_TABLE

	select NUMA_KEEP_MEMINFO if NUMA_MEMBLKS

	select FWCTL if CXL_FEATURES

	help

	  CXL is a bus that is electrically compatible with PCI Express, but

	  layers three protocols on that signalling (CXL.io, CXL.cache, and

drivers/cxl/core/features.c

+72 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0-only

/* Copyright(c) 2024-2025 Intel Corporation. All rights reserved. */

#include <linux/fwctl.h>

#include <linux/device.h>

#include <cxl/mailbox.h>

#include <cxl/features.h>
@@ -331,3 +332,74 @@ int cxl_set_feature(struct cxl_mailbox *cxl_mbox, 
		}

	} while (true);

}



/* FWCTL support */



static inline struct cxl_memdev *fwctl_to_memdev(struct fwctl_device *fwctl_dev)

{

	return to_cxl_memdev(fwctl_dev->dev.parent);

}



static int cxlctl_open_uctx(struct fwctl_uctx *uctx)

{

	return 0;

}



static void cxlctl_close_uctx(struct fwctl_uctx *uctx)

{

}



static void *cxlctl_fw_rpc(struct fwctl_uctx *uctx, enum fwctl_rpc_scope scope,

			   void *in, size_t in_len, size_t *out_len)

{

	/* Place holder */

	return ERR_PTR(-EOPNOTSUPP);

}



static const struct fwctl_ops cxlctl_ops = {

	.device_type = FWCTL_DEVICE_TYPE_CXL,

	.uctx_size = sizeof(struct fwctl_uctx),

	.open_uctx = cxlctl_open_uctx,

	.close_uctx = cxlctl_close_uctx,

	.fw_rpc = cxlctl_fw_rpc,

};



DEFINE_FREE(free_fwctl_dev, struct fwctl_device *, if (_T) fwctl_put(_T))



static void free_memdev_fwctl(void *_fwctl_dev)

{

	struct fwctl_device *fwctl_dev = _fwctl_dev;



	fwctl_unregister(fwctl_dev);

	fwctl_put(fwctl_dev);

}



int devm_cxl_setup_fwctl(struct cxl_memdev *cxlmd)

{

	struct cxl_dev_state *cxlds = cxlmd->cxlds;

	struct cxl_features_state *cxlfs;

	int rc;



	cxlfs = to_cxlfs(cxlds);

	if (!cxlfs)

		return -ENODEV;



	/* No need to setup FWCTL if there are no user allowed features found */

	if (!cxlfs->entries->num_user_features)

		return -ENODEV;



	struct fwctl_device *fwctl_dev __free(free_fwctl_dev) =

		_fwctl_alloc_device(&cxlmd->dev, &cxlctl_ops, sizeof(*fwctl_dev));

	if (!fwctl_dev)

		return -ENOMEM;



	rc = fwctl_register(fwctl_dev);

	if (rc)

		return rc;



	return devm_add_action_or_reset(&cxlmd->dev, free_memdev_fwctl,

					no_free_ptr(fwctl_dev));

}

EXPORT_SYMBOL_NS_GPL(devm_cxl_setup_fwctl, "CXL");



MODULE_IMPORT_NS("FWCTL");

drivers/cxl/pci.c

+4 −0
Original line number Diff line number Diff line
@@ -1013,6 +1013,10 @@ static int cxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id) 
	if (rc)

		return rc;



	rc = devm_cxl_setup_fwctl(cxlmd);

	if (rc)

		dev_dbg(&pdev->dev, "No CXL FWCTL setup\n");



	pmu_count = cxl_count_regblock(pdev, CXL_REGLOC_RBI_PMU);

	if (pmu_count < 0)

		return pmu_count;

include/cxl/features.h

+8 −0
Original line number Diff line number Diff line
@@ -4,6 +4,7 @@ 
#define __CXL_FEATURES_H__



#include <linux/uuid.h>

#include <linux/fwctl.h>



/* Feature UUIDs used by the kernel */

#define CXL_FEAT_PATROL_SCRUB_UUID						\
@@ -173,9 +174,11 @@ struct cxl_features_state { 
};



struct cxl_mailbox;

struct cxl_memdev;

#ifdef CONFIG_CXL_FEATURES

inline struct cxl_features_state *to_cxlfs(struct cxl_dev_state *cxlds);

int devm_cxl_setup_features(struct cxl_dev_state *cxlds);

int devm_cxl_setup_fwctl(struct cxl_memdev *cxlmd);

#else

static inline struct cxl_features_state *to_cxlfs(struct cxl_dev_state *cxlds)

{
@@ -186,6 +189,11 @@ static inline int devm_cxl_setup_features(struct cxl_dev_state *cxlds) 
{

	return -EOPNOTSUPP;

}



static inline int devm_cxl_setup_fwctl(struct cxl_memdev *cxlmd)

{

	return -EOPNOTSUPP;

}

#endif



#endif

include/uapi/fwctl/fwctl.h

+1 −0
Original line number Diff line number Diff line
@@ -43,6 +43,7 @@ enum { 
enum fwctl_device_type {

	FWCTL_DEVICE_TYPE_ERROR = 0,

	FWCTL_DEVICE_TYPE_MLX5 = 1,

	FWCTL_DEVICE_TYPE_CXL = 2,

};



/**