Re: [RFC PATCH v9 01/11] EDAC: Add generic EDAC RAS feature driver

[fan <nifan.cxl@gmail.com>]

On Tue, Jul 16, 2024 at 04:03:25PM +0100, shiju.jose@huawei.com wrote:
> From: Shiju Jose <shiju.jose@huawei.com>
> 
> Add generic EDAC driver supports registering RAS features supported
> in the system. The driver exposes feature's control attributes to the
> userspace in /sys/bus/edac/devices/<dev-name>/<ras-feature>/
> 
> 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>
> ---
>  drivers/edac/Makefile            |   1 +
>  drivers/edac/edac_ras_feature.c  | 155 +++++++++++++++++++++++++++++++
>  include/linux/edac_ras_feature.h |  66 +++++++++++++
>  3 files changed, 222 insertions(+)
>  create mode 100755 drivers/edac/edac_ras_feature.c
>  create mode 100755 include/linux/edac_ras_feature.h
> 
> diff --git a/drivers/edac/Makefile b/drivers/edac/Makefile
> index 9c09893695b7..c532b57a6d8a 100644
> --- a/drivers/edac/Makefile
> +++ b/drivers/edac/Makefile
> @@ -10,6 +10,7 @@ obj-$(CONFIG_EDAC)			:= edac_core.o
>  
>  edac_core-y	:= edac_mc.o edac_device.o edac_mc_sysfs.o
>  edac_core-y	+= edac_module.o edac_device_sysfs.o wq.o
> +edac_core-y	+= edac_ras_feature.o
>  
>  edac_core-$(CONFIG_EDAC_DEBUG)		+= debugfs.o
>  
> diff --git a/drivers/edac/edac_ras_feature.c b/drivers/edac/edac_ras_feature.c
> new file mode 100755
> index 000000000000..24a729fea66f
> --- /dev/null
> +++ b/drivers/edac/edac_ras_feature.c
> @@ -0,0 +1,155 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * EDAC RAS control feature driver supports registering RAS
> + * features with the EDAC and exposes the feature's control
> + * attributes to the userspace in sysfs.
> + *
> + * Copyright (c) 2024 HiSilicon Limited.
> + */
> +
> +#define pr_fmt(fmt)     "EDAC RAS CONTROL FEAT: " fmt
> +
> +#include <linux/edac_ras_feature.h>
> +
> +static void edac_ras_dev_release(struct device *dev)
> +{
> +	struct edac_ras_feat_ctx *ctx =
> +		container_of(dev, struct edac_ras_feat_ctx, dev);
> +
> +	kfree(ctx);
> +}
> +
> +const struct device_type edac_ras_dev_type = {
> +	.name = "edac_ras_dev",
> +	.release = edac_ras_dev_release,
> +};
> +
> +static void edac_ras_dev_unreg(void *data)
> +{
> +	device_unregister(data);
> +}
> +
> +static int edac_ras_feat_scrub_init(struct device *parent,
> +				    struct edac_scrub_data *sdata,
> +				    const struct edac_ras_feature *sfeat,
> +				    const struct attribute_group **attr_groups)
> +{
> +	sdata->ops = sfeat->scrub_ops;
> +	sdata->private = sfeat->scrub_ctx;
> +
> +	return 1;
> +}
> +
> +static int edac_ras_feat_ecs_init(struct device *parent,
> +				  struct edac_ecs_data *edata,
> +				  const struct edac_ras_feature *efeat,
> +				  const struct attribute_group **attr_groups)
> +{
> +	int num = efeat->ecs_info.num_media_frus;
> +
> +	edata->ops = efeat->ecs_ops;
> +	edata->private = efeat->ecs_ctx;
> +
> +	return num;
> +}
> +
> +/**
> + * edac_ras_dev_register - register device for ras features with edac
> + * @parent: client device.
> + * @name: client device's name.
> + * @private: parent driver's data to store in the context if any.
> + * @num_features: number of ras features to register.
> + * @ras_features: list of ras features to register.
> + *
> + * Returns 0 on success, error otherwise.
> + * The new edac_ras_feat_ctx would be freed automatically.
> + */
> +int edac_ras_dev_register(struct device *parent, char *name,
> +			  void *private, int num_features,
> +			  const struct edac_ras_feature *ras_features)
> +{
> +	const struct attribute_group **ras_attr_groups;
> +	struct edac_ras_feat_ctx *ctx;
> +	int attr_gcnt = 0;
> +	int ret, feat;
> +
> +	if (!parent || !name || !num_features || !ras_features)
> +		return -EINVAL;
> +
> +	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
> +	if (!ctx)
> +		return -ENOMEM;
> +
> +	ctx->dev.parent = parent;
> +	ctx->private = private;
> +
> +	/* Double parse so we can make space for attributes */
> +	for (feat = 0; feat < num_features; feat++) {
> +		switch (ras_features[feat].feat) {
> +		case ras_feat_scrub:
> +			attr_gcnt++;
> +			break;
> +		case ras_feat_ecs:
> +			attr_gcnt += ras_features[feat].ecs_info.num_media_frus;
> +			break;
> +		default:
> +			ret = -EINVAL;
> +			goto ctx_free;
> +		}
> +	}
> +
> +	ras_attr_groups = devm_kzalloc(parent,
> +				       (attr_gcnt + 1) * sizeof(*ras_attr_groups),
> +				       GFP_KERNEL);
> +	if (!ras_attr_groups) {
> +		ret = -ENOMEM;
> +		goto ctx_free;
> +	}
> +
> +	attr_gcnt = 0;
> +	for (feat = 0; feat < num_features; feat++, ras_features++) {
> +		if (ras_features->feat == ras_feat_scrub) {
> +			if (!ras_features->scrub_ops)
> +				continue;
> +			ret = edac_ras_feat_scrub_init(parent, &ctx->scrub,
> +						       ras_features, &ras_attr_groups[attr_gcnt]);
> +			if (ret < 0)
> +				goto ctx_free;
> +
> +			attr_gcnt += ret;
> +		} else if (ras_features->feat == ras_feat_ecs) {
> +			if (!ras_features->ecs_ops)
> +				continue;
> +			ret = edac_ras_feat_ecs_init(parent, &ctx->ecs,
> +						     ras_features, &ras_attr_groups[attr_gcnt]);
> +			if (ret < 0)
> +				goto ctx_free;
> +
> +			attr_gcnt += ret;
> +		} else {
> +			ret = -EINVAL;
> +			goto ctx_free;
We already check this in the first pass, cannot be reached in the second
pass.
> +		}
Why use if/else instead of using switch/case as above?
> +	}
> +	ras_attr_groups[attr_gcnt] = NULL;
> +	ctx->dev.bus = edac_get_sysfs_subsys();
> +	ctx->dev.type = &edac_ras_dev_type;
> +	ctx->dev.groups = ras_attr_groups;
> +	dev_set_drvdata(&ctx->dev, ctx);
> +	ret = dev_set_name(&ctx->dev, name);
> +	if (ret)
> +		goto ctx_free;
> +
> +	ret = device_register(&ctx->dev);
> +	if (ret) {
> +		put_device(&ctx->dev);
need to free ctx?
> +		return ret;
> +	}
> +
> +	return devm_add_action_or_reset(parent, edac_ras_dev_unreg, &ctx->dev);
> +
> +ctx_free:
> +	kfree(ctx);
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(edac_ras_dev_register);
> diff --git a/include/linux/edac_ras_feature.h b/include/linux/edac_ras_feature.h
> new file mode 100755
> index 000000000000..000e99141023
> --- /dev/null
> +++ b/include/linux/edac_ras_feature.h
> @@ -0,0 +1,66 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * EDAC RAS control features.
> + *
> + * Copyright (c) 2024 HiSilicon Limited.
> + */
> +
> +#ifndef __EDAC_RAS_FEAT_H
> +#define __EDAC_RAS_FEAT_H
> +
> +#include <linux/types.h>
> +#include <linux/edac.h>
> +
> +#define EDAC_RAS_NAME_LEN	128
> +
> +enum edac_ras_feat {
> +	ras_feat_scrub,
> +	ras_feat_ecs,
> +	ras_feat_max
> +};
Use uppercase for the strings.

Fan
> +
> +struct edac_ecs_ex_info {
> +	u16 num_media_frus;
> +};
> +
> +/*
> + * EDAC RAS feature information structure
> + */
> +struct edac_scrub_data {
> +	const struct edac_scrub_ops *ops;
> +	void *private;
> +};
> +
> +struct edac_ecs_data {
> +	const struct edac_ecs_ops *ops;
> +	void *private;
> +};
> +
> +struct device;
> +
> +struct edac_ras_feat_ctx {
> +	struct device dev;
> +	void *private;
> +	struct edac_scrub_data scrub;
> +	struct edac_ecs_data ecs;
> +};
> +
> +struct edac_ras_feature {
> +	enum edac_ras_feat feat;
> +	union {
> +		const struct edac_scrub_ops *scrub_ops;
> +		const struct edac_ecs_ops *ecs_ops;
> +	};
> +	union {
> +		struct edac_ecs_ex_info ecs_info;
> +	};
> +	union {
> +		void *scrub_ctx;
> +		void *ecs_ctx;
> +	};
> +};
> +
> +int edac_ras_dev_register(struct device *parent, char *dev_name,
> +			  void *parent_pvt_data, int num_features,
> +			  const struct edac_ras_feature *ras_features);
> +#endif /* __EDAC_RAS_FEAT_H */
> -- 
> 2.34.1
>