Commit 16280ded authored by Riana Tauro's avatar Riana Tauro Committed by Lucas De Marchi
Browse files

drm/xe: Add configfs to enable survivability mode 



Registers a configfs subsystem called 'xe' that creates a
directory in the mounted configfs directory (/sys/kernel/config)
Userspace can then create the device that has to be configured
under the xe directory

	mkdir /sys/kernel/config/xe/0000:03:00.0

The device created will have the following attributes to be
configured

	/sys/kernel/config/xe/
		.. 0000:03:00.0/
			... survivability_mode

v2: fix kernel-doc
    fix return value (Lucas)

v3: fix kernel-doc (Lucas)

Signed-off-by: default avatarRiana Tauro <riana.tauro@intel.com>
Reviewed-by: default avatarLucas De Marchi <lucas.demarchi@intel.com>
Link: https://lore.kernel.org/r/20250407051414.1651616-2-riana.tauro@intel.com


Signed-off-by: default avatarLucas De Marchi <lucas.demarchi@intel.com>
parent 1e1981b1

Documentation/gpu/xe/index.rst

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@@ -25,3 +25,4 @@ DG2, etc is provided to prototype the driver. 
   xe_debugging

   xe_devcoredump

   xe-drm-usage-stats.rst

   xe_configfs

Documentation/gpu/xe/xe_configfs.rst

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.. SPDX-License-Identifier: GPL-2.0+



.. _xe_configfs:



============

Xe Configfs

============



.. kernel-doc:: drivers/gpu/drm/xe/xe_configfs.c

   :doc: Xe Configfs

drivers/gpu/drm/xe/Makefile

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@@ -131,6 +131,7 @@ xe-$(CONFIG_DRM_XE_GPUSVM) += xe_svm.o 
xe-$(CONFIG_HWMON) += xe_hwmon.o



xe-$(CONFIG_PERF_EVENTS) += xe_pmu.o

xe-$(CONFIG_CONFIGFS_FS) += xe_configfs.o



# graphics virtualization (SR-IOV) support

xe-y += \

drivers/gpu/drm/xe/xe_configfs.c

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// SPDX-License-Identifier: MIT

/*

 * Copyright © 2025 Intel Corporation

 */



#include <linux/configfs.h>

#include <linux/init.h>

#include <linux/module.h>

#include <linux/pci.h>



#include "xe_configfs.h"

#include "xe_module.h"



/**

 * DOC: Xe Configfs

 *

 * Overview

 * =========

 *

 * Configfs is a filesystem-based manager of kernel objects. XE KMD registers a

 * configfs subsystem called ``'xe'`` that creates a directory in the mounted configfs directory

 * The user can create devices under this directory and configure them as necessary

 * See Documentation/filesystems/configfs.rst for more information about how configfs works.

 *

 * Create devices

 * ===============

 *

 * In order to create a device, the user has to create a directory inside ``'xe'``::

 *

 *	mkdir /sys/kernel/config/xe/0000:03:00.0/

 *

 * Every device created is populated by the driver with entries that can be

 * used to configure it::

 *

 *	/sys/kernel/config/xe/

 *		.. 0000:03:00.0/

 *			... survivability_mode

 *

 * Configure Attributes

 * ====================

 *

 * Survivability mode:

 * -------------------

 *

 * Enable survivability mode on supported cards. This setting only takes

 * effect when probing the device. Example to enable it::

 *

 *	# echo 1 > /sys/kernel/config/xe/0000:03:00.0/survivability_mode

 *	# echo 0000:03:00.0 > /sys/bus/pci/drivers/xe/bind  (Enters survivability mode if supported)

 *

 * Remove devices

 * ==============

 *

 * The created device directories can be removed using ``rmdir``::

 *

 *	rmdir /sys/kernel/config/xe/0000:03:00.0/

 */



struct xe_config_device {

	struct config_group group;



	bool survivability_mode;



	/* protects attributes */

	struct mutex lock;

};



static struct xe_config_device *to_xe_config_device(struct config_item *item)

{

	return container_of(to_config_group(item), struct xe_config_device, group);

}



static ssize_t survivability_mode_show(struct config_item *item, char *page)

{

	struct xe_config_device *dev = to_xe_config_device(item);



	return sprintf(page, "%d\n", dev->survivability_mode);

}



static ssize_t survivability_mode_store(struct config_item *item, const char *page, size_t len)

{

	struct xe_config_device *dev = to_xe_config_device(item);

	bool survivability_mode;

	int ret;



	ret = kstrtobool(page, &survivability_mode);

	if (ret)

		return ret;



	mutex_lock(&dev->lock);

	dev->survivability_mode = survivability_mode;

	mutex_unlock(&dev->lock);



	return len;

}



CONFIGFS_ATTR(, survivability_mode);



static struct configfs_attribute *xe_config_device_attrs[] = {

	&attr_survivability_mode,

	NULL,

};



static void xe_config_device_release(struct config_item *item)

{

	struct xe_config_device *dev = to_xe_config_device(item);



	mutex_destroy(&dev->lock);

	kfree(dev);

}



static struct configfs_item_operations xe_config_device_ops = {

	.release	= xe_config_device_release,

};



static const struct config_item_type xe_config_device_type = {

	.ct_item_ops	= &xe_config_device_ops,

	.ct_attrs	= xe_config_device_attrs,

	.ct_owner	= THIS_MODULE,

};



static struct config_group *xe_config_make_device_group(struct config_group *group,

							const char *name)

{

	unsigned int domain, bus, slot, function;

	struct xe_config_device *dev;

	struct pci_dev *pdev;

	int ret;



	ret = sscanf(name, "%04x:%02x:%02x.%x", &domain, &bus, &slot, &function);

	if (ret != 4)

		return ERR_PTR(-EINVAL);



	pdev = pci_get_domain_bus_and_slot(domain, bus, PCI_DEVFN(slot, function));

	if (!pdev)

		return ERR_PTR(-EINVAL);



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

	if (!dev)

		return ERR_PTR(-ENOMEM);



	config_group_init_type_name(&dev->group, name, &xe_config_device_type);



	mutex_init(&dev->lock);



	return &dev->group;

}



static struct configfs_group_operations xe_config_device_group_ops = {

	.make_group	= xe_config_make_device_group,

};



static const struct config_item_type xe_configfs_type = {

	.ct_group_ops	= &xe_config_device_group_ops,

	.ct_owner	= THIS_MODULE,

};



static struct configfs_subsystem xe_configfs = {

	.su_group = {

		.cg_item = {

			.ci_namebuf = "xe",

			.ci_type = &xe_configfs_type,

		},

	},

};



int __init xe_configfs_init(void)

{

	struct config_group *root = &xe_configfs.su_group;

	int ret;



	config_group_init(root);

	mutex_init(&xe_configfs.su_mutex);

	ret = configfs_register_subsystem(&xe_configfs);

	if (ret) {

		pr_err("Error %d while registering %s subsystem\n",

		       ret, root->cg_item.ci_namebuf);

		return ret;

	}



	return 0;

}



void __exit xe_configfs_exit(void)

{

	configfs_unregister_subsystem(&xe_configfs);

}

drivers/gpu/drm/xe/xe_configfs.h

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/* SPDX-License-Identifier: MIT */

/*

 * Copyright © 2025 Intel Corporation

 */

#ifndef _XE_CONFIGFS_H_

#define _XE_CONFIGFS_H_



#if IS_ENABLED(CONFIG_CONFIGFS_FS)

int xe_configfs_init(void);

void xe_configfs_exit(void);

#else

static inline int xe_configfs_init(void) { return 0; };

static inline void xe_configfs_exit(void) {};

#endif



#endif