Re: [PATCH v15 01/15] EDAC: Add support for EDAC device features control

[Fan Ni <nifan.cxl@gmail.com>]

On Fri, Nov 01, 2024 at 09:17:19AM +0000, shiju.jose@huawei.com wrote:
> From: Shiju Jose <shiju.jose@huawei.com>
> 
> Add generic EDAC device feature controls supporting the registration
> of RAS features available in the system. The driver exposes control
> attributes for these features to 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/edac_device.c | 101 +++++++++++++++++++++++++++++++++++++
>  include/linux/edac.h       |  30 +++++++++++
>  2 files changed, 131 insertions(+)
> 
> diff --git a/drivers/edac/edac_device.c b/drivers/edac/edac_device.c
> index 621dc2a5d034..e9229b5f8afe 100644
> --- a/drivers/edac/edac_device.c
> +++ b/drivers/edac/edac_device.c
> @@ -570,3 +570,104 @@ void edac_device_handle_ue_count(struct edac_device_ctl_info *edac_dev,
>  		      block ? block->name : "N/A", count, msg);
>  }
>  EXPORT_SYMBOL_GPL(edac_device_handle_ue_count);
> +
> +/* EDAC device feature */

The comment is not very helpful to me, seems not quite relevant to what
the function below does.

Fan
> +static void edac_dev_release(struct device *dev)
> +{
> +	struct edac_dev_feat_ctx *ctx = container_of(dev, struct edac_dev_feat_ctx, dev);
> +
> +	kfree(ctx->dev.groups);
> +	kfree(ctx);
> +}
> +
> +const struct device_type edac_dev_type = {
> +	.name = "edac_dev",
> +	.release = edac_dev_release,
> +};
> +
> +static void edac_dev_unreg(void *data)
> +{
> +	device_unregister(data);
> +}
> +
> +/**
> + * edac_dev_register - register device for RAS features with EDAC
> + * @parent: parent device.
> + * @name: parent 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.
> + *
> + * Return:
> + *  * %0       - Success.
> + *  * %-EINVAL - Invalid parameters passed.
> + *  * %-ENOMEM - Dynamic memory allocation failed.
> + *
> + */
> +int edac_dev_register(struct device *parent, char *name,
> +		      void *private, int num_features,
> +		      const struct edac_dev_feature *ras_features)
> +{
> +	const struct attribute_group **ras_attr_groups;
> +	struct edac_dev_feat_ctx *ctx;
> +	int attr_gcnt = 0;
> +	int ret, feat;
> +
> +	if (!parent || !name || !num_features || !ras_features)
> +		return -EINVAL;
> +
> +	/* Double parse to make space for attributes */
> +	for (feat = 0; feat < num_features; feat++) {
> +		switch (ras_features[feat].ft_type) {
> +		/* Add feature specific code */
> +		default:
> +			return -EINVAL;
> +		}
> +	}
> +
> +	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
> +	if (!ctx)
> +		return -ENOMEM;
> +
> +	ras_attr_groups = kcalloc(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++) {
> +		switch (ras_features->ft_type) {
> +		/* Add feature specific code */
> +		default:
> +			ret = -EINVAL;
> +			goto groups_free;
> +		}
> +	}
> +
> +	ctx->dev.parent = parent;
> +	ctx->dev.bus = edac_get_sysfs_subsys();
> +	ctx->dev.type = &edac_dev_type;
> +	ctx->dev.groups = ras_attr_groups;
> +	ctx->private = private;
> +	dev_set_drvdata(&ctx->dev, ctx);
> +
> +	ret = dev_set_name(&ctx->dev, name);
> +	if (ret)
> +		goto groups_free;
> +
> +	ret = device_register(&ctx->dev);
> +	if (ret) {
> +		put_device(&ctx->dev);
> +		return ret;
> +	}
> +
> +	return devm_add_action_or_reset(parent, edac_dev_unreg, &ctx->dev);
> +
> +groups_free:
> +	kfree(ras_attr_groups);
> +ctx_free:
> +	kfree(ctx);
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(edac_dev_register);
> diff --git a/include/linux/edac.h b/include/linux/edac.h
> index b4ee8961e623..e19706311ec0 100644
> --- a/include/linux/edac.h
> +++ b/include/linux/edac.h
> @@ -661,4 +661,34 @@ static inline struct dimm_info *edac_get_dimm(struct mem_ctl_info *mci,
>  
>  	return mci->dimms[index];
>  }
> +
> +/* EDAC device features */
> +
> +#define EDAC_FEAT_NAME_LEN	128
> +
> +/* RAS feature type */
> +enum edac_dev_feat {
> +	RAS_FEAT_MAX
> +};
> +
> +/* EDAC device feature information structure */
> +struct edac_dev_data {
> +	u8 instance;
> +	void *private;
> +};
> +
> +struct edac_dev_feat_ctx {
> +	struct device dev;
> +	void *private;
> +};
> +
> +struct edac_dev_feature {
> +	enum edac_dev_feat ft_type;
> +	u8 instance;
> +	void *ctx;
> +};
> +
> +int edac_dev_register(struct device *parent, char *dev_name,
> +		      void *parent_pvt_data, int num_features,
> +		      const struct edac_dev_feature *ras_features);
>  #endif /* _LINUX_EDAC_H_ */
> -- 
> 2.34.1
> 

-- 
Fan Ni