[v14,07/14] cxl/memfeature: Add CXL memory device patrol scrub control feature

From: Shiju Jose <shiju.jose@huawei.com>

CXL spec 3.1 section 8.2.9.9.11.1 describes the device patrol scrub control
feature. The device patrol scrub proactively locates and makes corrections
to errors in regular cycle.

Allow specifying the number of hours within which the patrol scrub must be
completed, subject to minimum and maximum limits reported by the device.
Also allow disabling scrub allowing trade-off error rates against
performance.

Add support for patrol scrub control on CXL memory devices.
Register with the EDAC device driver, which retrieves the scrub attribute
descriptors from EDAC scrub and exposes the sysfs scrub control attributes
to userspace. For example, scrub control for the CXL memory device
"cxl_mem0" is exposed in /sys/bus/edac/devices/cxl_mem0/scrubX/.

Additionally, add support for region-based CXL memory patrol scrub control.
CXL memory regions may be interleaved across one or more CXL memory
devices. For example, region-based scrub control for "cxl_region1" is
exposed in /sys/bus/edac/devices/cxl_region1/scrubX/.

Co-developed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Shiju Jose <shiju.jose@huawei.com>
---
 Documentation/edac/edac-scrub.rst |  74 ++++++
 drivers/cxl/Kconfig               |  18 ++
 drivers/cxl/core/Makefile         |   1 +
 drivers/cxl/core/memfeature.c     | 381 ++++++++++++++++++++++++++++++
 drivers/cxl/core/region.c         |   6 +
 drivers/cxl/cxlmem.h              |   7 +
 drivers/cxl/mem.c                 |   4 +
 7 files changed, 491 insertions(+)
 create mode 100644 Documentation/edac/edac-scrub.rst
 create mode 100644 drivers/cxl/core/memfeature.c

On 10/25/24 10:13 AM, shiju.jose@huawei.com wrote:
> From: Shiju Jose <shiju.jose@huawei.com>
> 
> CXL spec 3.1 section 8.2.9.9.11.1 describes the device patrol scrub control
> feature. The device patrol scrub proactively locates and makes corrections
> to errors in regular cycle.
> 
> Allow specifying the number of hours within which the patrol scrub must be
> completed, subject to minimum and maximum limits reported by the device.
> Also allow disabling scrub allowing trade-off error rates against
> performance.
> 
> Add support for patrol scrub control on CXL memory devices.
> Register with the EDAC device driver, which retrieves the scrub attribute
> descriptors from EDAC scrub and exposes the sysfs scrub control attributes
> to userspace. For example, scrub control for the CXL memory device
> "cxl_mem0" is exposed in /sys/bus/edac/devices/cxl_mem0/scrubX/.
> 
> Additionally, add support for region-based CXL memory patrol scrub control.
> CXL memory regions may be interleaved across one or more CXL memory
> devices. For example, region-based scrub control for "cxl_region1" is
> exposed in /sys/bus/edac/devices/cxl_region1/scrubX/.
> 
> Co-developed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> Signed-off-by: Shiju Jose <shiju.jose@huawei.com>
> ---
>  Documentation/edac/edac-scrub.rst |  74 ++++++
>  drivers/cxl/Kconfig               |  18 ++
>  drivers/cxl/core/Makefile         |   1 +
>  drivers/cxl/core/memfeature.c     | 381 ++++++++++++++++++++++++++++++
>  drivers/cxl/core/region.c         |   6 +
>  drivers/cxl/cxlmem.h              |   7 +
>  drivers/cxl/mem.c                 |   4 +
>  7 files changed, 491 insertions(+)
>  create mode 100644 Documentation/edac/edac-scrub.rst
>  create mode 100644 drivers/cxl/core/memfeature.c
> 
> diff --git a/Documentation/edac/edac-scrub.rst b/Documentation/edac/edac-scrub.rst
> new file mode 100644
> index 000000000000..4aad4974b208
> --- /dev/null
> +++ b/Documentation/edac/edac-scrub.rst
> @@ -0,0 +1,74 @@
> +.. SPDX-License-Identifier: GPL-2.0
> +
> +===================
> +EDAC Scrub control
> +===================
> +
> +Copyright (c) 2024 HiSilicon Limited.
> +
> +:Author:   Shiju Jose <shiju.jose@huawei.com>
> +:License:  The GNU Free Documentation License, Version 1.2
> +          (dual licensed under the GPL v2)
> +:Original Reviewers:
> +
> +- Written for: 6.13
> +- Updated for:
> +
> +Introduction
> +------------
> +The EDAC enhancement for RAS featurues exposes interfaces for controlling
> +the memory scrubbers in the system. The scrub device drivers in the
> +system register with the EDAC scrub. The driver exposes the
> +scrub controls to user in the sysfs.
> +
> +The File System
> +---------------
> +
> +The control attributes of the registered scrubber instance could be
> +accessed in the /sys/bus/edac/devices/<dev-name>/scrub*/
> +
> +sysfs
> +-----
> +
> +Sysfs files are documented in
> +`Documentation/ABI/testing/sysfs-edac-scrub-control`.
> +
> +Example
> +-------
> +
> +The usage takes the form shown in this example::
> +
> +1. CXL memory device patrol scrubber
> +1.1 device based
> +root@localhost:~# cat /sys/bus/edac/devices/cxl_mem0/scrub0/min_cycle_duration
> +3600
> +root@localhost:~# cat /sys/bus/edac/devices/cxl_mem0/scrub0/max_cycle_duration
> +918000
> +root@localhost:~# cat /sys/bus/edac/devices/cxl_mem0/scrub0/current_cycle_duration
> +43200
> +root@localhost:~# echo 54000 > /sys/bus/edac/devices/cxl_mem0/scrub0/current_cycle_duration
> +root@localhost:~# cat /sys/bus/edac/devices/cxl_mem0/scrub0/current_cycle_duration
> +54000
> +root@localhost:~# echo 1 > /sys/bus/edac/devices/cxl_mem0/scrub0/enable_background
> +root@localhost:~# cat /sys/bus/edac/devices/cxl_mem0/scrub0/enable_background
> +1
> +root@localhost:~# echo 0 > /sys/bus/edac/devices/cxl_mem0/scrub0/enable_background
> +root@localhost:~# cat /sys/bus/edac/devices/cxl_mem0/scrub0/enable_background
> +0
> +
> +1.2. region based
> +root@localhost:~# cat /sys/bus/edac/devices/cxl_region0/scrub0/min_cycle_duration
> +3600
> +root@localhost:~# cat /sys/bus/edac/devices/cxl_region0/scrub0/max_cycle_duration
> +918000
> +root@localhost:~# cat /sys/bus/edac/devices/cxl_region0/scrub0/current_cycle_duration
> +43200
> +root@localhost:~# echo 54000 > /sys/bus/edac/devices/cxl_region0/scrub0/current_cycle_duration
> +root@localhost:~# cat /sys/bus/edac/devices/cxl_region0/scrub0/current_cycle_duration
> +54000
> +root@localhost:~# echo 1 > /sys/bus/edac/devices/cxl_region0/scrub0/enable_background
> +root@localhost:~# cat /sys/bus/edac/devices/cxl_region0/scrub0/enable_background
> +1
> +root@localhost:~# echo 0 > /sys/bus/edac/devices/cxl_region0/scrub0/enable_background
> +root@localhost:~# cat /sys/bus/edac/devices/cxl_region0/scrub0/enable_background
> +0
> diff --git a/drivers/cxl/Kconfig b/drivers/cxl/Kconfig
> index 29c192f20082..6d79fb3e772e 100644
> --- a/drivers/cxl/Kconfig
> +++ b/drivers/cxl/Kconfig
> @@ -145,4 +145,22 @@ config CXL_REGION_INVALIDATION_TEST
>  	  If unsure, or if this kernel is meant for production environments,
>  	  say N.
>  
> +config CXL_RAS_FEAT
> +	tristate "CXL: Memory RAS features"
> +	depends on CXL_PCI
> +	depends on CXL_MEM
> +	depends on EDAC
> +	help
> +	  The CXL memory RAS feature control is optional and allows host to
> +	  control the RAS features configurations of CXL Type 3 devices.
> +
> +	  It registers with the EDAC device subsystem to expose control
> +	  attributes of CXL memory device's RAS features to the user.
> +	  It provides interface functions to support configuring the CXL
> +	  memory device's RAS features.
> +
> +	  Say 'y/m/n' to enable/disable control of the CXL.mem device's RAS features.
> +	  See section 8.2.9.9.11 of CXL 3.1 specification for the detailed
> +	  information of CXL memory device features.
> +
>  endif
> diff --git a/drivers/cxl/core/Makefile b/drivers/cxl/core/Makefile
> index 9259bcc6773c..2a3c7197bc23 100644
> --- a/drivers/cxl/core/Makefile
> +++ b/drivers/cxl/core/Makefile
> @@ -16,3 +16,4 @@ cxl_core-y += pmu.o
>  cxl_core-y += cdat.o
>  cxl_core-$(CONFIG_TRACING) += trace.o
>  cxl_core-$(CONFIG_CXL_REGION) += region.o
> +cxl_core-$(CONFIG_CXL_RAS_FEAT) += memfeature.o
> diff --git a/drivers/cxl/core/memfeature.c b/drivers/cxl/core/memfeature.c
> new file mode 100644
> index 000000000000..8fff00f62f8c
> --- /dev/null
> +++ b/drivers/cxl/core/memfeature.c
> @@ -0,0 +1,381 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * CXL memory RAS feature driver.
> + *
> + * Copyright (c) 2024 HiSilicon Limited.
> + *
> + *  - Supports functions to configure RAS features of the
> + *    CXL memory devices.
> + *  - Registers with the EDAC device subsystem driver to expose
> + *    the features sysfs attributes to the user for configuring
> + *    CXL memory RAS feature.
> + */
> +
> +#define pr_fmt(fmt)	"CXL MEM FEAT: " fmt
> +
> +#include <linux/cleanup.h>
> +#include <linux/edac.h>
> +#include <linux/limits.h>
> +#include <cxl.h>
> +#include <cxlmem.h>
> +
> +#define CXL_DEV_NUM_RAS_FEATURES	1
> +#define CXL_DEV_HOUR_IN_SECS	3600
> +
> +#define CXL_SCRUB_NAME_LEN	128
> +
> +/* CXL memory patrol scrub control definitions */
> +static const uuid_t cxl_patrol_scrub_uuid =
> +	UUID_INIT(0x96dad7d6, 0xfde8, 0x482b, 0xa7, 0x33, 0x75, 0x77, 0x4e, 0x06, 0xdb, 0x8a);
> +
> +/* CXL memory patrol scrub control functions */
> +struct cxl_patrol_scrub_context {
> +	u8 instance;
> +	u16 get_feat_size;
> +	u16 set_feat_size;
> +	u8 get_version;
> +	u8 set_version;
> +	u16 set_effects;
> +	struct cxl_memdev *cxlmd;
> +	struct cxl_region *cxlr;
> +};
> +
> +/**
> + * struct cxl_memdev_ps_params - CXL memory patrol scrub parameter data structure.
> + * @enable:     [IN & OUT] enable(1)/disable(0) patrol scrub.
> + * @scrub_cycle_changeable: [OUT] scrub cycle attribute of patrol scrub is changeable.
> + * @scrub_cycle_hrs:    [IN] Requested patrol scrub cycle in hours.
> + *                      [OUT] Current patrol scrub cycle in hours.
> + * @min_scrub_cycle_hrs:[OUT] minimum patrol scrub cycle in hours supported.
> + */
> +struct cxl_memdev_ps_params {
> +	bool enable;
> +	bool scrub_cycle_changeable;
> +	u16 scrub_cycle_hrs;
> +	u16 min_scrub_cycle_hrs;
> +};
> +
> +enum cxl_scrub_param {
> +	CXL_PS_PARAM_ENABLE,
> +	CXL_PS_PARAM_SCRUB_CYCLE,
> +};
> +
> +#define	CXL_MEMDEV_PS_SCRUB_CYCLE_CHANGE_CAP_MASK	BIT(0)
> +#define	CXL_MEMDEV_PS_SCRUB_CYCLE_REALTIME_REPORT_CAP_MASK	BIT(1)
> +#define	CXL_MEMDEV_PS_CUR_SCRUB_CYCLE_MASK	GENMASK(7, 0)
> +#define	CXL_MEMDEV_PS_MIN_SCRUB_CYCLE_MASK	GENMASK(15, 8)
> +#define	CXL_MEMDEV_PS_FLAG_ENABLED_MASK	BIT(0)
> +
> +struct cxl_memdev_ps_rd_attrs {
> +	u8 scrub_cycle_cap;
> +	__le16 scrub_cycle_hrs;
> +	u8 scrub_flags;
> +}  __packed;
> +
> +struct cxl_memdev_ps_wr_attrs {
> +	u8 scrub_cycle_hrs;
> +	u8 scrub_flags;
> +}  __packed;
> +
> +static int cxl_mem_ps_get_attrs(struct cxl_memdev_state *mds,
> +				struct cxl_memdev_ps_params *params)
> +{
> +	size_t rd_data_size = sizeof(struct cxl_memdev_ps_rd_attrs);
> +	size_t data_size;
> +	struct cxl_memdev_ps_rd_attrs *rd_attrs __free(kfree) =
> +						kmalloc(rd_data_size, GFP_KERNEL);
> +	if (!rd_attrs)
> +		return -ENOMEM;
> +
> +	data_size = cxl_get_feature(mds, cxl_patrol_scrub_uuid,
> +				    CXL_GET_FEAT_SEL_CURRENT_VALUE,
> +				    rd_attrs, rd_data_size);
> +	if (!data_size)
> +		return -EIO;
> +
> +	params->scrub_cycle_changeable = FIELD_GET(CXL_MEMDEV_PS_SCRUB_CYCLE_CHANGE_CAP_MASK,
> +						   rd_attrs->scrub_cycle_cap);
> +	params->enable = FIELD_GET(CXL_MEMDEV_PS_FLAG_ENABLED_MASK,
> +				   rd_attrs->scrub_flags);
> +	params->scrub_cycle_hrs = FIELD_GET(CXL_MEMDEV_PS_CUR_SCRUB_CYCLE_MASK,
> +					    rd_attrs->scrub_cycle_hrs);
> +	params->min_scrub_cycle_hrs = FIELD_GET(CXL_MEMDEV_PS_MIN_SCRUB_CYCLE_MASK,
> +						rd_attrs->scrub_cycle_hrs);
> +
> +	return 0;
> +}
> +
> +static int cxl_ps_get_attrs(struct device *dev, void *drv_data,

Would a union be better than a void *drv_data for all the places this is used as a parameter? How many variations of this are there?

DJ

> +			    struct cxl_memdev_ps_params *params)
> +{
> +	struct cxl_patrol_scrub_context *cxl_ps_ctx = drv_data;
> +	struct cxl_memdev *cxlmd;
> +	struct cxl_dev_state *cxlds;
> +	struct cxl_memdev_state *mds;
> +	u16 min_scrub_cycle = 0;
> +	int i, ret;
> +
> +	if (cxl_ps_ctx->cxlr) {
> +		struct cxl_region *cxlr = cxl_ps_ctx->cxlr;
> +		struct cxl_region_params *p = &cxlr->params;
> +
> +		for (i = p->interleave_ways - 1; i >= 0; i--) {
> +			struct cxl_endpoint_decoder *cxled = p->targets[i];
> +
> +			cxlmd = cxled_to_memdev(cxled);
> +			cxlds = cxlmd->cxlds;
> +			mds = to_cxl_memdev_state(cxlds);
> +			ret = cxl_mem_ps_get_attrs(mds, params);
> +			if (ret)
> +				return ret;
> +
> +			if (params->min_scrub_cycle_hrs > min_scrub_cycle)
> +				min_scrub_cycle = params->min_scrub_cycle_hrs;
> +		}
> +		params->min_scrub_cycle_hrs = min_scrub_cycle;
> +		return 0;
> +	}
> +	cxlmd = cxl_ps_ctx->cxlmd;
> +	cxlds = cxlmd->cxlds;
> +	mds = to_cxl_memdev_state(cxlds);
> +
> +	return cxl_mem_ps_get_attrs(mds, params);
> +}
> +
> +static int cxl_mem_ps_set_attrs(struct device *dev, void *drv_data,
> +				struct cxl_memdev_state *mds,
> +				struct cxl_memdev_ps_params *params,
> +				enum cxl_scrub_param param_type)
> +{
> +	struct cxl_patrol_scrub_context *cxl_ps_ctx = drv_data;
> +	struct cxl_memdev_ps_wr_attrs wr_attrs;
> +	struct cxl_memdev_ps_params rd_params;
> +	int ret;
> +
> +	ret = cxl_mem_ps_get_attrs(mds, &rd_params);
> +	if (ret) {
> +		dev_err(dev, "Get cxlmemdev patrol scrub params failed ret=%d\n",
> +			ret);
> +		return ret;
> +	}
> +
> +	switch (param_type) {
> +	case CXL_PS_PARAM_ENABLE:
> +		wr_attrs.scrub_flags = FIELD_PREP(CXL_MEMDEV_PS_FLAG_ENABLED_MASK,
> +						  params->enable);
> +		wr_attrs.scrub_cycle_hrs = FIELD_PREP(CXL_MEMDEV_PS_CUR_SCRUB_CYCLE_MASK,
> +						      rd_params.scrub_cycle_hrs);
> +		break;
> +	case CXL_PS_PARAM_SCRUB_CYCLE:
> +		if (params->scrub_cycle_hrs < rd_params.min_scrub_cycle_hrs) {
> +			dev_err(dev, "Invalid CXL patrol scrub cycle(%d) to set\n",
> +				params->scrub_cycle_hrs);
> +			dev_err(dev, "Minimum supported CXL patrol scrub cycle in hour %d\n",
> +				rd_params.min_scrub_cycle_hrs);
> +			return -EINVAL;
> +		}
> +		wr_attrs.scrub_cycle_hrs = FIELD_PREP(CXL_MEMDEV_PS_CUR_SCRUB_CYCLE_MASK,
> +						      params->scrub_cycle_hrs);
> +		wr_attrs.scrub_flags = FIELD_PREP(CXL_MEMDEV_PS_FLAG_ENABLED_MASK,
> +						  rd_params.enable);
> +		break;
> +	}
> +
> +	ret = cxl_set_feature(mds, cxl_patrol_scrub_uuid,
> +			      cxl_ps_ctx->set_version,
> +			      &wr_attrs, sizeof(wr_attrs),
> +			      CXL_SET_FEAT_FLAG_DATA_SAVED_ACROSS_RESET);
> +	if (ret) {
> +		dev_err(dev, "CXL patrol scrub set feature failed ret=%d\n", ret);
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static int cxl_ps_set_attrs(struct device *dev, void *drv_data,
> +			    struct cxl_memdev_ps_params *params,
> +			    enum cxl_scrub_param param_type)
> +{
> +	struct cxl_patrol_scrub_context *cxl_ps_ctx = drv_data;
> +	struct cxl_memdev *cxlmd;
> +	struct cxl_dev_state *cxlds;
> +	struct cxl_memdev_state *mds;
> +	int ret, i;
> +
> +	if (cxl_ps_ctx->cxlr) {
> +		struct cxl_region *cxlr = cxl_ps_ctx->cxlr;
> +		struct cxl_region_params *p = &cxlr->params;
> +
> +		for (i = p->interleave_ways - 1; i >= 0; i--) {
> +			struct cxl_endpoint_decoder *cxled = p->targets[i];
> +
> +			cxlmd = cxled_to_memdev(cxled);
> +			cxlds = cxlmd->cxlds;
> +			mds = to_cxl_memdev_state(cxlds);
> +			ret = cxl_mem_ps_set_attrs(dev, drv_data, mds,
> +						   params, param_type);
> +			if (ret)
> +				return ret;
> +		}
> +		return 0;
> +	}
> +	cxlmd = cxl_ps_ctx->cxlmd;
> +	cxlds = cxlmd->cxlds;
> +	mds = to_cxl_memdev_state(cxlds);
> +
> +	return cxl_mem_ps_set_attrs(dev, drv_data, mds, params, param_type);
> +}
> +
> +static int cxl_patrol_scrub_get_enabled_bg(struct device *dev, void *drv_data, bool *enabled)
> +{
> +	struct cxl_memdev_ps_params params;
> +	int ret;
> +
> +	ret = cxl_ps_get_attrs(dev, drv_data, &params);
> +	if (ret)
> +		return ret;
> +
> +	*enabled = params.enable;
> +
> +	return 0;
> +}
> +
> +static int cxl_patrol_scrub_set_enabled_bg(struct device *dev, void *drv_data, bool enable)
> +{
> +	struct cxl_memdev_ps_params params = {
> +		.enable = enable,
> +	};
> +
> +	return cxl_ps_set_attrs(dev, drv_data, &params, CXL_PS_PARAM_ENABLE);
> +}
> +
> +static int cxl_patrol_scrub_read_min_scrub_cycle(struct device *dev, void *drv_data,
> +						 u32 *min)
> +{
> +	struct cxl_memdev_ps_params params;
> +	int ret;
> +
> +	ret = cxl_ps_get_attrs(dev, drv_data, &params);
> +	if (ret)
> +		return ret;
> +	*min = params.min_scrub_cycle_hrs * CXL_DEV_HOUR_IN_SECS;
> +
> +	return 0;
> +}
> +
> +static int cxl_patrol_scrub_read_max_scrub_cycle(struct device *dev, void *drv_data,
> +						 u32 *max)
> +{
> +	*max = U8_MAX * CXL_DEV_HOUR_IN_SECS; /* Max set by register size */
> +
> +	return 0;
> +}
> +
> +static int cxl_patrol_scrub_read_scrub_cycle(struct device *dev, void *drv_data,
> +					     u32 *scrub_cycle_secs)
> +{
> +	struct cxl_memdev_ps_params params;
> +	int ret;
> +
> +	ret = cxl_ps_get_attrs(dev, drv_data, &params);
> +	if (ret)
> +		return ret;
> +
> +	*scrub_cycle_secs = params.scrub_cycle_hrs * CXL_DEV_HOUR_IN_SECS;
> +
> +	return 0;
> +}
> +
> +static int cxl_patrol_scrub_write_scrub_cycle(struct device *dev, void *drv_data,
> +					      u32 scrub_cycle_secs)
> +{
> +	struct cxl_memdev_ps_params params = {
> +		.scrub_cycle_hrs = scrub_cycle_secs / CXL_DEV_HOUR_IN_SECS,
> +	};
> +
> +	return cxl_ps_set_attrs(dev, drv_data, &params, CXL_PS_PARAM_SCRUB_CYCLE);
> +}
> +
> +static const struct edac_scrub_ops cxl_ps_scrub_ops = {
> +	.get_enabled_bg = cxl_patrol_scrub_get_enabled_bg,
> +	.set_enabled_bg = cxl_patrol_scrub_set_enabled_bg,
> +	.get_min_cycle = cxl_patrol_scrub_read_min_scrub_cycle,
> +	.get_max_cycle = cxl_patrol_scrub_read_max_scrub_cycle,
> +	.get_cycle_duration = cxl_patrol_scrub_read_scrub_cycle,
> +	.set_cycle_duration = cxl_patrol_scrub_write_scrub_cycle,
> +};
> +
> +int cxl_mem_ras_features_init(struct cxl_memdev *cxlmd, struct cxl_region *cxlr)
> +{
> +	struct edac_dev_feature ras_features[CXL_DEV_NUM_RAS_FEATURES];
> +	struct cxl_patrol_scrub_context *cxl_ps_ctx;
> +	char cxl_dev_name[CXL_SCRUB_NAME_LEN];
> +	struct cxl_feat_entry feat_entry;
> +	struct cxl_memdev_state *mds;
> +	struct cxl_dev_state *cxlds;
> +	int num_ras_features = 0;
> +	u8 scrub_inst = 0;
> +	int rc, i;
> +
> +	if (cxlr) {
> +		struct cxl_region_params *p = &cxlr->params;
> +
> +		for (i = p->interleave_ways - 1; i >= 0; i--) {
> +			struct cxl_endpoint_decoder *cxled = p->targets[i];
> +
> +			cxlmd = cxled_to_memdev(cxled);
> +			cxlds = cxlmd->cxlds;
> +			mds = to_cxl_memdev_state(cxlds);
> +			memset(&feat_entry, 0, sizeof(feat_entry));
> +			rc = cxl_get_supported_feature_entry(mds, &cxl_patrol_scrub_uuid,
> +							     &feat_entry);
> +			if (rc < 0)
> +				return rc;
> +			if (!(feat_entry.attr_flags & CXL_FEAT_ENTRY_FLAG_CHANGABLE))
> +				return -EOPNOTSUPP;
> +		}
> +	} else {
> +		cxlds = cxlmd->cxlds;
> +		mds = to_cxl_memdev_state(cxlds);
> +		rc = cxl_get_supported_feature_entry(mds, &cxl_patrol_scrub_uuid,
> +						     &feat_entry);
> +		if (rc < 0)
> +			return rc;
> +
> +		if (!(feat_entry.attr_flags & CXL_FEAT_ENTRY_FLAG_CHANGABLE))
> +			return -EOPNOTSUPP;
> +	}
> +
> +	cxl_ps_ctx = devm_kzalloc(&cxlmd->dev, sizeof(*cxl_ps_ctx), GFP_KERNEL);
> +	if (!cxl_ps_ctx)
> +		return -ENOMEM;
> +
> +	*cxl_ps_ctx = (struct cxl_patrol_scrub_context) {
> +		.get_feat_size = feat_entry.get_feat_size,
> +		.set_feat_size = feat_entry.set_feat_size,
> +		.get_version = feat_entry.get_feat_ver,
> +		.set_version = feat_entry.set_feat_ver,
> +		.set_effects = feat_entry.set_effects,
> +		.instance = scrub_inst++,
> +	};
> +	if (cxlr) {
> +		snprintf(cxl_dev_name, sizeof(cxl_dev_name),
> +			 "cxl_region%d", cxlr->id);
> +		cxl_ps_ctx->cxlr = cxlr;
> +	} else {
> +		snprintf(cxl_dev_name, sizeof(cxl_dev_name),
> +			 "%s_%s", "cxl", dev_name(&cxlmd->dev));
> +		cxl_ps_ctx->cxlmd = cxlmd;
> +	}
> +
> +	ras_features[num_ras_features].ft_type = RAS_FEAT_SCRUB;
> +	ras_features[num_ras_features].instance = cxl_ps_ctx->instance;
> +	ras_features[num_ras_features].scrub_ops = &cxl_ps_scrub_ops;
> +	ras_features[num_ras_features].ctx = cxl_ps_ctx;
> +	num_ras_features++;
> +
> +	return edac_dev_register(&cxlmd->dev, cxl_dev_name, NULL,
> +				 num_ras_features, ras_features);
> +}
> +EXPORT_SYMBOL_NS_GPL(cxl_mem_ras_features_init, CXL);
> diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
> index e701e4b04032..4292765606cd 100644
> --- a/drivers/cxl/core/region.c
> +++ b/drivers/cxl/core/region.c
> @@ -3443,6 +3443,12 @@ static int cxl_region_probe(struct device *dev)
>  					p->res->start, p->res->end, cxlr,
>  					is_system_ram) > 0)
>  			return 0;
> +
> +		rc = cxl_mem_ras_features_init(NULL, cxlr);
> +		if (rc)
> +			dev_warn(&cxlr->dev, "CXL RAS features init for region_id=%d failed\n",
> +				 cxlr->id);
> +
>  		return devm_cxl_add_dax_region(cxlr);
>  	default:
>  		dev_dbg(&cxlr->dev, "unsupported region mode: %d\n",
> diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h
> index fb356be8b426..9259c5d70a65 100644
> --- a/drivers/cxl/cxlmem.h
> +++ b/drivers/cxl/cxlmem.h
> @@ -933,6 +933,13 @@ int cxl_trigger_poison_list(struct cxl_memdev *cxlmd);
>  int cxl_inject_poison(struct cxl_memdev *cxlmd, u64 dpa);
>  int cxl_clear_poison(struct cxl_memdev *cxlmd, u64 dpa);
>  
> +#if IS_ENABLED(CONFIG_CXL_RAS_FEAT)
> +int cxl_mem_ras_features_init(struct cxl_memdev *cxlmd, struct cxl_region *cxlr);
> +#else
> +static inline int cxl_mem_ras_features_init(struct cxl_memdev *cxlmd, struct cxl_region *cxlr)
> +{ return 0; }
> +#endif
> +
>  #ifdef CONFIG_CXL_SUSPEND
>  void cxl_mem_active_inc(void);
>  void cxl_mem_active_dec(void);
> diff --git a/drivers/cxl/mem.c b/drivers/cxl/mem.c
> index a9fd5cd5a0d2..23ef99e02182 100644
> --- a/drivers/cxl/mem.c
> +++ b/drivers/cxl/mem.c
> @@ -116,6 +116,10 @@ static int cxl_mem_probe(struct device *dev)
>  	if (!cxlds->media_ready)
>  		return -EBUSY;
>  
> +	rc = cxl_mem_ras_features_init(cxlmd, NULL);
> +	if (rc)
> +		dev_warn(&cxlmd->dev, "CXL RAS features init failed\n");
> +
>  	/*
>  	 * Someone is trying to reattach this device after it lost its port
>  	 * connection (an endpoint port previously registered by this memdev was

>-----Original Message-----
>From: Dave Jiang <dave.jiang@intel.com>
>Sent: 29 October 2024 16:32
>To: Shiju Jose <shiju.jose@huawei.com>; linux-edac@vger.kernel.org; linux-
>cxl@vger.kernel.org; linux-acpi@vger.kernel.org; linux-mm@kvack.org; linux-
>kernel@vger.kernel.org
>Cc: bp@alien8.de; tony.luck@intel.com; rafael@kernel.org; lenb@kernel.org;
>mchehab@kernel.org; dan.j.williams@intel.com; dave@stgolabs.net; Jonathan
>Cameron <jonathan.cameron@huawei.com>; gregkh@linuxfoundation.org;
>sudeep.holla@arm.com; jassisinghbrar@gmail.com; alison.schofield@intel.com;
>vishal.l.verma@intel.com; ira.weiny@intel.com; david@redhat.com;
>Vilas.Sridharan@amd.com; leo.duran@amd.com; Yazen.Ghannam@amd.com;
>rientjes@google.com; jiaqiyan@google.com; Jon.Grimm@amd.com;
>dave.hansen@linux.intel.com; naoya.horiguchi@nec.com;
>james.morse@arm.com; jthoughton@google.com; somasundaram.a@hpe.com;
>erdemaktas@google.com; pgonda@google.com; duenwen@google.com;
>gthelen@google.com; wschwartz@amperecomputing.com;
>dferguson@amperecomputing.com; wbs@os.amperecomputing.com;
>nifan.cxl@gmail.com; tanxiaofei <tanxiaofei@huawei.com>; Zengtao (B)
><prime.zeng@hisilicon.com>; Roberto Sassu <roberto.sassu@huawei.com>;
>kangkang.shen@futurewei.com; wanghuiqiang <wanghuiqiang@huawei.com>;
>Linuxarm <linuxarm@huawei.com>
>Subject: Re: [PATCH v14 07/14] cxl/memfeature: Add CXL memory device patrol
>scrub control feature
>
>
>
>On 10/25/24 10:13 AM, shiju.jose@huawei.com wrote:
>> From: Shiju Jose <shiju.jose@huawei.com>
>>
>> CXL spec 3.1 section 8.2.9.9.11.1 describes the device patrol scrub
>> control feature. The device patrol scrub proactively locates and makes
>> corrections to errors in regular cycle.
>>
>> Allow specifying the number of hours within which the patrol scrub
>> must be completed, subject to minimum and maximum limits reported by the
>device.
>> Also allow disabling scrub allowing trade-off error rates against
>> performance.
>>
>> Add support for patrol scrub control on CXL memory devices.
>> Register with the EDAC device driver, which retrieves the scrub
>> attribute descriptors from EDAC scrub and exposes the sysfs scrub
>> control attributes to userspace. For example, scrub control for the
>> CXL memory device "cxl_mem0" is exposed in
>/sys/bus/edac/devices/cxl_mem0/scrubX/.
>>
>> Additionally, add support for region-based CXL memory patrol scrub control.
>> CXL memory regions may be interleaved across one or more CXL memory
>> devices. For example, region-based scrub control for "cxl_region1" is
>> exposed in /sys/bus/edac/devices/cxl_region1/scrubX/.
>>
>> Co-developed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
>> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
>> Signed-off-by: Shiju Jose <shiju.jose@huawei.com>
>> ---
>>  Documentation/edac/edac-scrub.rst |  74 ++++++
>>  drivers/cxl/Kconfig               |  18 ++
>>  drivers/cxl/core/Makefile         |   1 +
>>  drivers/cxl/core/memfeature.c     | 381 ++++++++++++++++++++++++++++++
>>  drivers/cxl/core/region.c         |   6 +
>>  drivers/cxl/cxlmem.h              |   7 +
>>  drivers/cxl/mem.c                 |   4 +
>>  7 files changed, 491 insertions(+)
>>  create mode 100644 Documentation/edac/edac-scrub.rst  create mode
>> 100644 drivers/cxl/core/memfeature.c
>>
>> diff --git a/Documentation/edac/edac-scrub.rst
>> b/Documentation/edac/edac-scrub.rst
>> new file mode 100644
>> index 000000000000..4aad4974b208
>> --- /dev/null
>> +++ b/Documentation/edac/edac-scrub.rst
>> @@ -0,0 +1,74 @@
>> +.. SPDX-License-Identifier: GPL-2.0
>> +
[...]

>> +static int cxl_mem_ps_get_attrs(struct cxl_memdev_state *mds,
>> +				struct cxl_memdev_ps_params *params) {
>> +	size_t rd_data_size = sizeof(struct cxl_memdev_ps_rd_attrs);
>> +	size_t data_size;
>> +	struct cxl_memdev_ps_rd_attrs *rd_attrs __free(kfree) =
>> +						kmalloc(rd_data_size,
>GFP_KERNEL);
>> +	if (!rd_attrs)
>> +		return -ENOMEM;
>> +
>> +	data_size = cxl_get_feature(mds, cxl_patrol_scrub_uuid,
>> +				    CXL_GET_FEAT_SEL_CURRENT_VALUE,
>> +				    rd_attrs, rd_data_size);
>> +	if (!data_size)
>> +		return -EIO;
>> +
>> +	params->scrub_cycle_changeable =
>FIELD_GET(CXL_MEMDEV_PS_SCRUB_CYCLE_CHANGE_CAP_MASK,
>> +						   rd_attrs->scrub_cycle_cap);
>> +	params->enable =
>FIELD_GET(CXL_MEMDEV_PS_FLAG_ENABLED_MASK,
>> +				   rd_attrs->scrub_flags);
>> +	params->scrub_cycle_hrs =
>FIELD_GET(CXL_MEMDEV_PS_CUR_SCRUB_CYCLE_MASK,
>> +					    rd_attrs->scrub_cycle_hrs);
>> +	params->min_scrub_cycle_hrs =
>FIELD_GET(CXL_MEMDEV_PS_MIN_SCRUB_CYCLE_MASK,
>> +						rd_attrs->scrub_cycle_hrs);
>> +
>> +	return 0;
>> +}
>> +
>> +static int cxl_ps_get_attrs(struct device *dev, void *drv_data,
>
>Would a union be better than a void *drv_data for all the places this is used as a
>parameter? How many variations of this are there?
>
>DJ
Hi Dave,

Can you give more info on this given this is a generic callback for the scrub control and each
implementation will have its own context struct (for eg. struct cxl_patrol_scrub_context here
for CXL scrub control), which in turn will be passed in and out as opaque data.

Thanks,
Shiju
>
>> +			    struct cxl_memdev_ps_params *params) {
>> +	struct cxl_patrol_scrub_context *cxl_ps_ctx = drv_data;
>> +	struct cxl_memdev *cxlmd;
>> +	struct cxl_dev_state *cxlds;
>> +	struct cxl_memdev_state *mds;
>> +	u16 min_scrub_cycle = 0;
>> +	int i, ret;
>> +
>> +	if (cxl_ps_ctx->cxlr) {
>> +		struct cxl_region *cxlr = cxl_ps_ctx->cxlr;
>> +		struct cxl_region_params *p = &cxlr->params;
>> +
>> +		for (i = p->interleave_ways - 1; i >= 0; i--) {
>> +			struct cxl_endpoint_decoder *cxled = p->targets[i];
>> +
>> +			cxlmd = cxled_to_memdev(cxled);
>> +			cxlds = cxlmd->cxlds;
>> +			mds = to_cxl_memdev_state(cxlds);
>> +			ret = cxl_mem_ps_get_attrs(mds, params);
>> +			if (ret)
>> +				return ret;
>> +
>> +			if (params->min_scrub_cycle_hrs > min_scrub_cycle)
>> +				min_scrub_cycle = params-
>>min_scrub_cycle_hrs;
>> +		}
>> +		params->min_scrub_cycle_hrs = min_scrub_cycle;
>> +		return 0;
>> +	}
>> +	cxlmd = cxl_ps_ctx->cxlmd;
>> +	cxlds = cxlmd->cxlds;
>> +	mds = to_cxl_memdev_state(cxlds);
>> +
>> +	return cxl_mem_ps_get_attrs(mds, params); }
>> +
[...]
>

On 10/29/24 10:00 AM, Shiju Jose wrote:
> 
> 
>> -----Original Message-----
>> From: Dave Jiang <dave.jiang@intel.com>
>> Sent: 29 October 2024 16:32
>> To: Shiju Jose <shiju.jose@huawei.com>; linux-edac@vger.kernel.org; linux-
>> cxl@vger.kernel.org; linux-acpi@vger.kernel.org; linux-mm@kvack.org; linux-
>> kernel@vger.kernel.org
>> Cc: bp@alien8.de; tony.luck@intel.com; rafael@kernel.org; lenb@kernel.org;
>> mchehab@kernel.org; dan.j.williams@intel.com; dave@stgolabs.net; Jonathan
>> Cameron <jonathan.cameron@huawei.com>; gregkh@linuxfoundation.org;
>> sudeep.holla@arm.com; jassisinghbrar@gmail.com; alison.schofield@intel.com;
>> vishal.l.verma@intel.com; ira.weiny@intel.com; david@redhat.com;
>> Vilas.Sridharan@amd.com; leo.duran@amd.com; Yazen.Ghannam@amd.com;
>> rientjes@google.com; jiaqiyan@google.com; Jon.Grimm@amd.com;
>> dave.hansen@linux.intel.com; naoya.horiguchi@nec.com;
>> james.morse@arm.com; jthoughton@google.com; somasundaram.a@hpe.com;
>> erdemaktas@google.com; pgonda@google.com; duenwen@google.com;
>> gthelen@google.com; wschwartz@amperecomputing.com;
>> dferguson@amperecomputing.com; wbs@os.amperecomputing.com;
>> nifan.cxl@gmail.com; tanxiaofei <tanxiaofei@huawei.com>; Zengtao (B)
>> <prime.zeng@hisilicon.com>; Roberto Sassu <roberto.sassu@huawei.com>;
>> kangkang.shen@futurewei.com; wanghuiqiang <wanghuiqiang@huawei.com>;
>> Linuxarm <linuxarm@huawei.com>
>> Subject: Re: [PATCH v14 07/14] cxl/memfeature: Add CXL memory device patrol
>> scrub control feature
>>
>>
>>
>> On 10/25/24 10:13 AM, shiju.jose@huawei.com wrote:
>>> From: Shiju Jose <shiju.jose@huawei.com>
>>>
>>> CXL spec 3.1 section 8.2.9.9.11.1 describes the device patrol scrub
>>> control feature. The device patrol scrub proactively locates and makes
>>> corrections to errors in regular cycle.
>>>
>>> Allow specifying the number of hours within which the patrol scrub
>>> must be completed, subject to minimum and maximum limits reported by the
>> device.
>>> Also allow disabling scrub allowing trade-off error rates against
>>> performance.
>>>
>>> Add support for patrol scrub control on CXL memory devices.
>>> Register with the EDAC device driver, which retrieves the scrub
>>> attribute descriptors from EDAC scrub and exposes the sysfs scrub
>>> control attributes to userspace. For example, scrub control for the
>>> CXL memory device "cxl_mem0" is exposed in
>> /sys/bus/edac/devices/cxl_mem0/scrubX/.
>>>
>>> Additionally, add support for region-based CXL memory patrol scrub control.
>>> CXL memory regions may be interleaved across one or more CXL memory
>>> devices. For example, region-based scrub control for "cxl_region1" is
>>> exposed in /sys/bus/edac/devices/cxl_region1/scrubX/.
>>>
>>> Co-developed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
>>> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
>>> Signed-off-by: Shiju Jose <shiju.jose@huawei.com>
>>> ---
>>>  Documentation/edac/edac-scrub.rst |  74 ++++++
>>>  drivers/cxl/Kconfig               |  18 ++
>>>  drivers/cxl/core/Makefile         |   1 +
>>>  drivers/cxl/core/memfeature.c     | 381 ++++++++++++++++++++++++++++++
>>>  drivers/cxl/core/region.c         |   6 +
>>>  drivers/cxl/cxlmem.h              |   7 +
>>>  drivers/cxl/mem.c                 |   4 +
>>>  7 files changed, 491 insertions(+)
>>>  create mode 100644 Documentation/edac/edac-scrub.rst  create mode
>>> 100644 drivers/cxl/core/memfeature.c
>>>
>>> diff --git a/Documentation/edac/edac-scrub.rst
>>> b/Documentation/edac/edac-scrub.rst
>>> new file mode 100644
>>> index 000000000000..4aad4974b208
>>> --- /dev/null
>>> +++ b/Documentation/edac/edac-scrub.rst
>>> @@ -0,0 +1,74 @@
>>> +.. SPDX-License-Identifier: GPL-2.0
>>> +
> [...]
> 
>>> +static int cxl_mem_ps_get_attrs(struct cxl_memdev_state *mds,
>>> +				struct cxl_memdev_ps_params *params) {
>>> +	size_t rd_data_size = sizeof(struct cxl_memdev_ps_rd_attrs);
>>> +	size_t data_size;
>>> +	struct cxl_memdev_ps_rd_attrs *rd_attrs __free(kfree) =
>>> +						kmalloc(rd_data_size,
>> GFP_KERNEL);
>>> +	if (!rd_attrs)
>>> +		return -ENOMEM;
>>> +
>>> +	data_size = cxl_get_feature(mds, cxl_patrol_scrub_uuid,
>>> +				    CXL_GET_FEAT_SEL_CURRENT_VALUE,
>>> +				    rd_attrs, rd_data_size);
>>> +	if (!data_size)
>>> +		return -EIO;
>>> +
>>> +	params->scrub_cycle_changeable =
>> FIELD_GET(CXL_MEMDEV_PS_SCRUB_CYCLE_CHANGE_CAP_MASK,
>>> +						   rd_attrs->scrub_cycle_cap);
>>> +	params->enable =
>> FIELD_GET(CXL_MEMDEV_PS_FLAG_ENABLED_MASK,
>>> +				   rd_attrs->scrub_flags);
>>> +	params->scrub_cycle_hrs =
>> FIELD_GET(CXL_MEMDEV_PS_CUR_SCRUB_CYCLE_MASK,
>>> +					    rd_attrs->scrub_cycle_hrs);
>>> +	params->min_scrub_cycle_hrs =
>> FIELD_GET(CXL_MEMDEV_PS_MIN_SCRUB_CYCLE_MASK,
>>> +						rd_attrs->scrub_cycle_hrs);
>>> +
>>> +	return 0;
>>> +}
>>> +
>>> +static int cxl_ps_get_attrs(struct device *dev, void *drv_data,
>>
>> Would a union be better than a void *drv_data for all the places this is used as a
>> parameter? How many variations of this are there?
>>
>> DJ
> Hi Dave,
> 
> Can you give more info on this given this is a generic callback for the scrub control and each
> implementation will have its own context struct (for eg. struct cxl_patrol_scrub_context here
> for CXL scrub control), which in turn will be passed in and out as opaque data.

Mainly I'm just seeing a lot of calls with (void *). Just asking if we want to make it a union that contains 'struct cxl_patrol_scrub_context' and etc.

> 
> Thanks,
> Shiju
>>
>>> +			    struct cxl_memdev_ps_params *params) {
>>> +	struct cxl_patrol_scrub_context *cxl_ps_ctx = drv_data;
>>> +	struct cxl_memdev *cxlmd;
>>> +	struct cxl_dev_state *cxlds;
>>> +	struct cxl_memdev_state *mds;
>>> +	u16 min_scrub_cycle = 0;
>>> +	int i, ret;
>>> +
>>> +	if (cxl_ps_ctx->cxlr) {
>>> +		struct cxl_region *cxlr = cxl_ps_ctx->cxlr;
>>> +		struct cxl_region_params *p = &cxlr->params;
>>> +
>>> +		for (i = p->interleave_ways - 1; i >= 0; i--) {
>>> +			struct cxl_endpoint_decoder *cxled = p->targets[i];
>>> +
>>> +			cxlmd = cxled_to_memdev(cxled);
>>> +			cxlds = cxlmd->cxlds;
>>> +			mds = to_cxl_memdev_state(cxlds);
>>> +			ret = cxl_mem_ps_get_attrs(mds, params);
>>> +			if (ret)
>>> +				return ret;
>>> +
>>> +			if (params->min_scrub_cycle_hrs > min_scrub_cycle)
>>> +				min_scrub_cycle = params-
>>> min_scrub_cycle_hrs;
>>> +		}
>>> +		params->min_scrub_cycle_hrs = min_scrub_cycle;
>>> +		return 0;
>>> +	}
>>> +	cxlmd = cxl_ps_ctx->cxlmd;
>>> +	cxlds = cxlmd->cxlds;
>>> +	mds = to_cxl_memdev_state(cxlds);
>>> +
>>> +	return cxl_mem_ps_get_attrs(mds, params); }
>>> +
> [...]
>>
>

On Fri, Oct 25, 2024 at 06:13:48PM +0100, shiju.jose@huawei.com wrote:
> diff --git a/Documentation/edac/edac-scrub.rst b/Documentation/edac/edac-scrub.rst
> new file mode 100644
> index 000000000000..4aad4974b208
> --- /dev/null
> +++ b/Documentation/edac/edac-scrub.rst
> @@ -0,0 +1,74 @@
> +.. SPDX-License-Identifier: GPL-2.0
> +
> +===================
> +EDAC Scrub control
> +===================
> +
> +Copyright (c) 2024 HiSilicon Limited.
> +
> +:Author:   Shiju Jose <shiju.jose@huawei.com>
> +:License:  The GNU Free Documentation License, Version 1.2
> +          (dual licensed under the GPL v2)
> +:Original Reviewers:
> +
> +- Written for: 6.13
> +- Updated for:
> +
> +Introduction
> +------------
> +The EDAC enhancement for RAS featurues exposes interfaces for controlling
> +the memory scrubbers in the system. The scrub device drivers in the
> +system register with the EDAC scrub. The driver exposes the
> +scrub controls to user in the sysfs.
> +
> +The File System
> +---------------
> +
> +The control attributes of the registered scrubber instance could be
> +accessed in the /sys/bus/edac/devices/<dev-name>/scrub*/
> +
> +sysfs
> +-----
> +
> +Sysfs files are documented in
> +`Documentation/ABI/testing/sysfs-edac-scrub-control`.
> +
> +Example
> +-------
> +
> +The usage takes the form shown in this example::
> +
> +1. CXL memory device patrol scrubber
> +1.1 device based
> +root@localhost:~# cat /sys/bus/edac/devices/cxl_mem0/scrub0/min_cycle_duration
> +3600
> +root@localhost:~# cat /sys/bus/edac/devices/cxl_mem0/scrub0/max_cycle_duration
> +918000
> +root@localhost:~# cat /sys/bus/edac/devices/cxl_mem0/scrub0/current_cycle_duration
> +43200
> +root@localhost:~# echo 54000 > /sys/bus/edac/devices/cxl_mem0/scrub0/current_cycle_duration
> +root@localhost:~# cat /sys/bus/edac/devices/cxl_mem0/scrub0/current_cycle_duration
> +54000
> +root@localhost:~# echo 1 > /sys/bus/edac/devices/cxl_mem0/scrub0/enable_background
> +root@localhost:~# cat /sys/bus/edac/devices/cxl_mem0/scrub0/enable_background
> +1
> +root@localhost:~# echo 0 > /sys/bus/edac/devices/cxl_mem0/scrub0/enable_background
> +root@localhost:~# cat /sys/bus/edac/devices/cxl_mem0/scrub0/enable_background
> +0
> +
> +1.2. region based
> +root@localhost:~# cat /sys/bus/edac/devices/cxl_region0/scrub0/min_cycle_duration
> +3600
> +root@localhost:~# cat /sys/bus/edac/devices/cxl_region0/scrub0/max_cycle_duration
> +918000
> +root@localhost:~# cat /sys/bus/edac/devices/cxl_region0/scrub0/current_cycle_duration
> +43200
> +root@localhost:~# echo 54000 > /sys/bus/edac/devices/cxl_region0/scrub0/current_cycle_duration
> +root@localhost:~# cat /sys/bus/edac/devices/cxl_region0/scrub0/current_cycle_duration
> +54000
> +root@localhost:~# echo 1 > /sys/bus/edac/devices/cxl_region0/scrub0/enable_background
> +root@localhost:~# cat /sys/bus/edac/devices/cxl_region0/scrub0/enable_background
> +1
> +root@localhost:~# echo 0 > /sys/bus/edac/devices/cxl_region0/scrub0/enable_background
> +root@localhost:~# cat /sys/bus/edac/devices/cxl_region0/scrub0/enable_background
> +0

This file's addition belongs to some EDAC patch in the series, not here.

It could be a separate, last patch in the series too, once everything is
settled.

Thx.