[v12,10/17] 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 CXL memory device based patrol scrub control.
Register with EDAC RAS control feature driver, which gets the scrub attr
descriptors from the EDAC scrub and expose sysfs scrub control attributes
to the userspace.
For example CXL device based scrub control for the CXL mem0 device is
exposed in /sys/bus/edac/devices/cxl_mem0/scrub*/

Also add support for region based CXL memory patrol scrub control.
CXL memory region 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/scrub*/

Open Questions:
Q1: CXL 3.1 spec defined patrol scrub control feature at CXL memory devices
with supporting set scrub cycle and enable/disable scrub. but not based on
HPA range. Thus presently scrub control for a region is implemented based
on all associated CXL memory devices.
What is the exact use case for the CXL region based scrub control?
How the HPA range, which Dan asked for region based scrubbing is used?
Does spec change is required for patrol scrub control feature with support
for setting the HPA range?

Q2: Both CXL device based and CXL region based scrub control would be
enabled at the same time in a system?

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     | 372 ++++++++++++++++++++++++++++++
 drivers/cxl/core/region.c         |   6 +
 drivers/cxl/cxlmem.h              |   7 +
 drivers/cxl/mem.c                 |   4 +
 7 files changed, 482 insertions(+)
 create mode 100644 Documentation/edac/edac-scrub.rst
 create mode 100644 drivers/cxl/core/memfeature.c

On Wed, Sep 11, 2024 at 10:04:39AM +0100, 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 CXL memory device based patrol scrub control.
> Register with EDAC RAS control feature driver, which gets the scrub attr
> descriptors from the EDAC scrub and expose sysfs scrub control attributes
> to the userspace.
> For example CXL device based scrub control for the CXL mem0 device is
> exposed in /sys/bus/edac/devices/cxl_mem0/scrub*/
> 
> Also add support for region based CXL memory patrol scrub control.
> CXL memory region 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/scrub*/
> 
> Open Questions:
> Q1: CXL 3.1 spec defined patrol scrub control feature at CXL memory devices
> with supporting set scrub cycle and enable/disable scrub. but not based on
> HPA range. Thus presently scrub control for a region is implemented based
> on all associated CXL memory devices.
> What is the exact use case for the CXL region based scrub control?
> How the HPA range, which Dan asked for region based scrubbing is used?
> Does spec change is required for patrol scrub control feature with support
> for setting the HPA range?
> 
> Q2: Both CXL device based and CXL region based scrub control would be
> enabled at the same time in a system?
> 
> 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>

Hi Shiju,

When trying the following ops with this patchset, I acctually noticed
something unexpected.

---------------------------------
root@localhost:~# dmesg -C
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:~# echo 3200 > /sys/bus/edac/devices/cxl_mem0/scrub0/current_cycle_duration
-bash: echo: write error: Invalid argument
root@localhost:~# dmesg
[ 4950.038767] cxl_pci:__cxl_pci_mbox_send_cmd:263: cxl_pci 0000:0d:00.0: Sending command: 0x0501
[ 4950.038952] cxl_pci:cxl_pci_mbox_wait_for_doorbell:74: cxl_pci 0000:0d:00.0: Doorbell wait took 0ms
[ 4972.487087] cxl_pci:__cxl_pci_mbox_send_cmd:263: cxl_pci 0000:0d:00.0: Sending command: 0x0501
[ 4972.487339] cxl_pci:cxl_pci_mbox_wait_for_doorbell:74: cxl_pci 0000:0d:00.0: Doorbell wait took 0ms
[ 4972.487509] cxl_mem mem0: Invalid CXL patrol scrub cycle(0) to set
[ 4972.488287] cxl_mem mem0: Minimum supported CXL patrol scrub cycle in hour 0
-----------------------

If you check the last line of the dmesg output, it seems we did not
print out the minimum scrub cycle duration correctly.

Fan


> ---
>  Documentation/edac/edac-scrub.rst |  74 ++++++
>  drivers/cxl/Kconfig               |  18 ++
>  drivers/cxl/core/Makefile         |   1 +
>  drivers/cxl/core/memfeature.c     | 372 ++++++++++++++++++++++++++++++
>  drivers/cxl/core/region.c         |   6 +
>  drivers/cxl/cxlmem.h              |   7 +
>  drivers/cxl/mem.c                 |   4 +
>  7 files changed, 482 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..243035957e99
> --- /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: 6.12
> +- 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 99b5c25be079..394bdbc4de87 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
> +	bool "CXL: Memory RAS features"
> +	depends on CXL_PCI
> +	depends on CXL_MEM
> +	depends on EDAC
> +	help
> +	  The CXL memory RAS feature control is optional allows host to control
> +	  the RAS features configurations of CXL Type 3 devices.
> +
> +	  Registers with the EDAC device subsystem to expose control attributes
> +	  of CXL memory device's RAS features to the user.
> +	  Provides interface functions to support configuring the CXL memory
> +	  device's RAS features.
> +
> +	  Say 'y/n' to enable/disable CXL.mem device'ss RAS features control.
> +	  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..90c68d20b02b
> --- /dev/null
> +++ b/drivers/cxl/core/memfeature.c
> @@ -0,0 +1,372 @@
> +// 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 <cxlmem.h>
> +#include <linux/cleanup.h>
> +#include <linux/limits.h>
> +#include <cxl.h>
> +#include <linux/edac.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_dev_state *cxlds,
> +				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(cxlds, 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,
> +			    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;
> +	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;
> +			ret = cxl_mem_ps_get_attrs(cxlds, 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;
> +
> +	return cxl_mem_ps_get_attrs(cxlds, params);
> +}
> +
> +static int cxl_mem_ps_set_attrs(struct device *dev, void *drv_data,
> +				struct cxl_dev_state *cxlds,
> +				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(cxlds, &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",
> +				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(cxlds, 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;
> +	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;
> +			ret = cxl_mem_ps_set_attrs(dev, drv_data, cxlds,
> +						   params, param_type);
> +			if (ret)
> +				return ret;
> +		}
> +	} else {
> +		cxlmd = cxl_ps_ctx->cxlmd;
> +		cxlds = cxlmd->cxlds;
> +
> +		return cxl_mem_ps_set_attrs(dev, drv_data, cxlds, params, param_type);
> +	}
> +
> +	return 0;
> +}
> +
> +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,
> +	.min_cycle_read = cxl_patrol_scrub_read_min_scrub_cycle,
> +	.max_cycle_read = cxl_patrol_scrub_read_max_scrub_cycle,
> +	.cycle_duration_read = cxl_patrol_scrub_read_scrub_cycle,
> +	.cycle_duration_write = 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_dev_state *cxlds;
> +	struct cxl_patrol_scrub_context *cxl_ps_ctx;
> +	struct cxl_feat_entry feat_entry;
> +	char cxl_dev_name[CXL_SCRUB_NAME_LEN];
> +	int rc, i, num_ras_features = 0;
> +
> +	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;
> +			memset(&feat_entry, 0, sizeof(feat_entry));
> +			rc = cxl_get_supported_feature_entry(cxlds, &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;
> +		rc = cxl_get_supported_feature_entry(cxlds, &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) {
> +		.instance = cxl_ps_ctx->instance,
> +		.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,
> +	};
> +	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].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 21ad5f242875..1cc29ec9ffac 100644
> --- a/drivers/cxl/core/region.c
> +++ b/drivers/cxl/core/region.c
> @@ -3434,6 +3434,12 @@ 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 b565a061a4e3..2187c3378eaa 100644
> --- a/drivers/cxl/cxlmem.h
> +++ b/drivers/cxl/cxlmem.h
> @@ -889,6 +889,13 @@ 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);
>  
> +#ifdef 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 7de232eaeb17..be2e69548909 100644
> --- a/drivers/cxl/mem.c
> +++ b/drivers/cxl/mem.c
> @@ -117,6 +117,10 @@ 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
> -- 
> 2.34.1
>

>-----Original Message-----
>From: Fan Ni <nifan.cxl@gmail.com>
>Sent: 30 September 2024 18:39
>To: Shiju Jose <shiju.jose@huawei.com>
>Cc: linux-edac@vger.kernel.org; linux-cxl@vger.kernel.org; linux-
>acpi@vger.kernel.org; linux-mm@kvack.org; linux-kernel@vger.kernel.org;
>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>; dave.jiang@intel.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; mike.malvestuto@intel.com; gthelen@google.com;
>wschwartz@amperecomputing.com; dferguson@amperecomputing.com;
>wbs@os.amperecomputing.com; nifan.cxl@gmail.com; jgroves@micron.com;
>vsalve@micron.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 v12 10/17] cxl/memfeature: Add CXL memory device patrol
>scrub control feature
>
>On Wed, Sep 11, 2024 at 10:04:39AM +0100, 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 CXL memory device based patrol scrub control.
>> Register with EDAC RAS control feature driver, which gets the scrub
>> attr descriptors from the EDAC scrub and expose sysfs scrub control
>> attributes to the userspace.
>> For example CXL device based scrub control for the CXL mem0 device is
>> exposed in /sys/bus/edac/devices/cxl_mem0/scrub*/
>>
>> Also add support for region based CXL memory patrol scrub control.
>> CXL memory region 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/scrub*/
>>
>> Open Questions:
>> Q1: CXL 3.1 spec defined patrol scrub control feature at CXL memory
>> devices with supporting set scrub cycle and enable/disable scrub. but
>> not based on HPA range. Thus presently scrub control for a region is
>> implemented based on all associated CXL memory devices.
>> What is the exact use case for the CXL region based scrub control?
>> How the HPA range, which Dan asked for region based scrubbing is used?
>> Does spec change is required for patrol scrub control feature with
>> support for setting the HPA range?
>>
>> Q2: Both CXL device based and CXL region based scrub control would be
>> enabled at the same time in a system?
>>
>> 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>
>
>Hi Shiju,
>
>When trying the following ops with this patchset, I acctually noticed something
>unexpected.
>
>---------------------------------
>root@localhost:~# dmesg -C
>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:~# echo 3200 >
>/sys/bus/edac/devices/cxl_mem0/scrub0/current_cycle_duration
>-bash: echo: write error: Invalid argument root@localhost:~# dmesg [
>4950.038767] cxl_pci:__cxl_pci_mbox_send_cmd:263: cxl_pci 0000:0d:00.0:
>Sending command: 0x0501 [ 4950.038952]
>cxl_pci:cxl_pci_mbox_wait_for_doorbell:74: cxl_pci 0000:0d:00.0: Doorbell wait
>took 0ms [ 4972.487087] cxl_pci:__cxl_pci_mbox_send_cmd:263: cxl_pci
>0000:0d:00.0: Sending command: 0x0501 [ 4972.487339]
>cxl_pci:cxl_pci_mbox_wait_for_doorbell:74: cxl_pci 0000:0d:00.0: Doorbell wait
>took 0ms [ 4972.487509] cxl_mem mem0: Invalid CXL patrol scrub cycle(0) to
>set [ 4972.488287] cxl_mem mem0: Minimum supported CXL patrol scrub cycle
>in hour 0
>-----------------------
>
>If you check the last line of the dmesg output, it seems we did not print out the
>minimum scrub cycle duration correctly.
Hi Fan,

Thanks for checking and reporting the bug.
dev_err(dev, "Minimum supported CXL patrol scrub cycle in hour %d\n",
	 params->min_scrub_cycle_hrs);
In the above error print,  
I will change, params->min_scrub_cycle_hrs to rd_params.min_scrub_cycle_hrs
>
>Fan

Thanks,
Shiju
>
>
>> ---
>>  Documentation/edac/edac-scrub.rst |  74 ++++++
>>  drivers/cxl/Kconfig               |  18 ++
>>  drivers/cxl/core/Makefile         |   1 +
>>  drivers/cxl/core/memfeature.c     | 372 ++++++++++++++++++++++++++++++
>>  drivers/cxl/core/region.c         |   6 +
>>  drivers/cxl/cxlmem.h              |   7 +
>>  drivers/cxl/mem.c                 |   4 +
>>  7 files changed, 482 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..243035957e99
>> --- /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: 6.12
>> +- 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
>> 99b5c25be079..394bdbc4de87 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
>> +	bool "CXL: Memory RAS features"
>> +	depends on CXL_PCI
>> +	depends on CXL_MEM
>> +	depends on EDAC
>> +	help
>> +	  The CXL memory RAS feature control is optional allows host to control
>> +	  the RAS features configurations of CXL Type 3 devices.
>> +
>> +	  Registers with the EDAC device subsystem to expose control attributes
>> +	  of CXL memory device's RAS features to the user.
>> +	  Provides interface functions to support configuring the CXL memory
>> +	  device's RAS features.
>> +
>> +	  Say 'y/n' to enable/disable CXL.mem device'ss RAS features control.
>> +	  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..90c68d20b02b
>> --- /dev/null
>> +++ b/drivers/cxl/core/memfeature.c
>> @@ -0,0 +1,372 @@
>> +// 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 <cxlmem.h>
>> +#include <linux/cleanup.h>
>> +#include <linux/limits.h>
>> +#include <cxl.h>
>> +#include <linux/edac.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_dev_state *cxlds,
>> +				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(cxlds, 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,
>> +			    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;
>> +	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;
>> +			ret = cxl_mem_ps_get_attrs(cxlds, 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;
>> +
>> +	return cxl_mem_ps_get_attrs(cxlds, params); }
>> +
>> +static int cxl_mem_ps_set_attrs(struct device *dev, void *drv_data,
>> +				struct cxl_dev_state *cxlds,
>> +				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(cxlds, &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",
>> +				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(cxlds, 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;
>> +	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;
>> +			ret = cxl_mem_ps_set_attrs(dev, drv_data, cxlds,
>> +						   params, param_type);
>> +			if (ret)
>> +				return ret;
>> +		}
>> +	} else {
>> +		cxlmd = cxl_ps_ctx->cxlmd;
>> +		cxlds = cxlmd->cxlds;
>> +
>> +		return cxl_mem_ps_set_attrs(dev, drv_data, cxlds, params,
>param_type);
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>> +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,
>> +	.min_cycle_read = cxl_patrol_scrub_read_min_scrub_cycle,
>> +	.max_cycle_read = cxl_patrol_scrub_read_max_scrub_cycle,
>> +	.cycle_duration_read = cxl_patrol_scrub_read_scrub_cycle,
>> +	.cycle_duration_write = 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_dev_state *cxlds;
>> +	struct cxl_patrol_scrub_context *cxl_ps_ctx;
>> +	struct cxl_feat_entry feat_entry;
>> +	char cxl_dev_name[CXL_SCRUB_NAME_LEN];
>> +	int rc, i, num_ras_features = 0;
>> +
>> +	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;
>> +			memset(&feat_entry, 0, sizeof(feat_entry));
>> +			rc = cxl_get_supported_feature_entry(cxlds,
>&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;
>> +		rc = cxl_get_supported_feature_entry(cxlds,
>&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) {
>> +		.instance = cxl_ps_ctx->instance,
>> +		.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,
>> +	};
>> +	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].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 21ad5f242875..1cc29ec9ffac 100644
>> --- a/drivers/cxl/core/region.c
>> +++ b/drivers/cxl/core/region.c
>> @@ -3434,6 +3434,12 @@ 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
>> b565a061a4e3..2187c3378eaa 100644
>> --- a/drivers/cxl/cxlmem.h
>> +++ b/drivers/cxl/cxlmem.h
>> @@ -889,6 +889,13 @@ 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);
>>
>> +#ifdef 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
>> 7de232eaeb17..be2e69548909 100644
>> --- a/drivers/cxl/mem.c
>> +++ b/drivers/cxl/mem.c
>> @@ -117,6 +117,10 @@ 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
>> --
>> 2.34.1
>>
>
>--
>Fan Ni

On Wed, Sep 11, 2024 at 10:04:39AM +0100, 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 CXL memory device based patrol scrub control.
> Register with EDAC RAS control feature driver, which gets the scrub attr
> descriptors from the EDAC scrub and expose sysfs scrub control attributes
> to the userspace.
> For example CXL device based scrub control for the CXL mem0 device is
> exposed in /sys/bus/edac/devices/cxl_mem0/scrub*/
> 
> Also add support for region based CXL memory patrol scrub control.
> CXL memory region 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/scrub*/
> 
> Open Questions:
> Q1: CXL 3.1 spec defined patrol scrub control feature at CXL memory devices
> with supporting set scrub cycle and enable/disable scrub. but not based on
> HPA range. Thus presently scrub control for a region is implemented based
> on all associated CXL memory devices.
> What is the exact use case for the CXL region based scrub control?
> How the HPA range, which Dan asked for region based scrubbing is used?
> Does spec change is required for patrol scrub control feature with support
> for setting the HPA range?
> 
> Q2: Both CXL device based and CXL region based scrub control would be
> enabled at the same time in a system?
> 
> 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     | 372 ++++++++++++++++++++++++++++++
>  drivers/cxl/core/region.c         |   6 +
>  drivers/cxl/cxlmem.h              |   7 +
>  drivers/cxl/mem.c                 |   4 +
>  7 files changed, 482 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..243035957e99
> --- /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: 6.12
> +- 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 99b5c25be079..394bdbc4de87 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
> +	bool "CXL: Memory RAS features"

If EDAC is compiled as module, it will lead to a situlation where EDAC is a
module, and CXL_RAS_FEAT is compiled in, and causing compile issue like below

----
  CC [M]  arch/arm64/crypto/aes-neon-blk.mod.o
  CC [M]  arch/arm64/crypto/sha512-arm64.mod.o
  CC [M]  arch/arm64/crypto/chacha-neon.mod.o
  CC [M]  arch/arm64/crypto/aes-neon-bs.mod.o
  CC [M]  fs/nfs/blocklayout/blocklayoutdriver.mod.o
  CC [M]  fs/pstore/ramoops.mod.o
  CC [M]  fs/ubifs/ubifs.mod.o
  CC [M]  fs/fuse/fuse.mod.o
  CC [M]  fs/fuse/cuse.mod.o
  CC [M]  fs/overlayfs/overlay.mod.o
  CC [M]  fs/btrfs/btrfs.mod.o
aarch64-linux-gnu-ld: drivers/cxl/core/memfeature.o: in function `cxl_mem_ras_features_init':
/home/fan/cxl/linux-edac/drivers/cxl/core/memfeature.c:1133:(.text+0x3ac): undefined reference to `edac_dev_register'
----
I think it should be "tristate" instead of "bool" like blew.

diff --git a/drivers/cxl/Kconfig b/drivers/cxl/Kconfig
index 394bdbc4de87..b717a152d2a5 100644
--- a/drivers/cxl/Kconfig
+++ b/drivers/cxl/Kconfig
@@ -146,7 +146,7 @@ config CXL_REGION_INVALIDATION_TEST
          say N.
 
 config CXL_RAS_FEAT
-       bool "CXL: Memory RAS features"
+       tristate "CXL: Memory RAS features"
        depends on CXL_PCI
        depends on CXL_MEM
        depends on EDAC


Fan

> +	depends on CXL_PCI
> +	depends on CXL_MEM
> +	depends on EDAC
> +	help
> +	  The CXL memory RAS feature control is optional allows host to control
> +	  the RAS features configurations of CXL Type 3 devices.
> +
> +	  Registers with the EDAC device subsystem to expose control attributes
> +	  of CXL memory device's RAS features to the user.
> +	  Provides interface functions to support configuring the CXL memory
> +	  device's RAS features.
> +
> +	  Say 'y/n' to enable/disable CXL.mem device'ss RAS features control.
> +	  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..90c68d20b02b
> --- /dev/null
> +++ b/drivers/cxl/core/memfeature.c
> @@ -0,0 +1,372 @@
> +// 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 <cxlmem.h>
> +#include <linux/cleanup.h>
> +#include <linux/limits.h>
> +#include <cxl.h>
> +#include <linux/edac.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_dev_state *cxlds,
> +				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(cxlds, 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,
> +			    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;
> +	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;
> +			ret = cxl_mem_ps_get_attrs(cxlds, 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;
> +
> +	return cxl_mem_ps_get_attrs(cxlds, params);
> +}
> +
> +static int cxl_mem_ps_set_attrs(struct device *dev, void *drv_data,
> +				struct cxl_dev_state *cxlds,
> +				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(cxlds, &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",
> +				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(cxlds, 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;
> +	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;
> +			ret = cxl_mem_ps_set_attrs(dev, drv_data, cxlds,
> +						   params, param_type);
> +			if (ret)
> +				return ret;
> +		}
> +	} else {
> +		cxlmd = cxl_ps_ctx->cxlmd;
> +		cxlds = cxlmd->cxlds;
> +
> +		return cxl_mem_ps_set_attrs(dev, drv_data, cxlds, params, param_type);
> +	}
> +
> +	return 0;
> +}
> +
> +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,
> +	.min_cycle_read = cxl_patrol_scrub_read_min_scrub_cycle,
> +	.max_cycle_read = cxl_patrol_scrub_read_max_scrub_cycle,
> +	.cycle_duration_read = cxl_patrol_scrub_read_scrub_cycle,
> +	.cycle_duration_write = 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_dev_state *cxlds;
> +	struct cxl_patrol_scrub_context *cxl_ps_ctx;
> +	struct cxl_feat_entry feat_entry;
> +	char cxl_dev_name[CXL_SCRUB_NAME_LEN];
> +	int rc, i, num_ras_features = 0;
> +
> +	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;
> +			memset(&feat_entry, 0, sizeof(feat_entry));
> +			rc = cxl_get_supported_feature_entry(cxlds, &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;
> +		rc = cxl_get_supported_feature_entry(cxlds, &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) {
> +		.instance = cxl_ps_ctx->instance,
> +		.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,
> +	};
> +	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].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 21ad5f242875..1cc29ec9ffac 100644
> --- a/drivers/cxl/core/region.c
> +++ b/drivers/cxl/core/region.c
> @@ -3434,6 +3434,12 @@ 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 b565a061a4e3..2187c3378eaa 100644
> --- a/drivers/cxl/cxlmem.h
> +++ b/drivers/cxl/cxlmem.h
> @@ -889,6 +889,13 @@ 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);
>  
> +#ifdef 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 7de232eaeb17..be2e69548909 100644
> --- a/drivers/cxl/mem.c
> +++ b/drivers/cxl/mem.c
> @@ -117,6 +117,10 @@ 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
> -- 
> 2.34.1
>