Re: [RFC v4 2/4] hotplug/drcinfo: Provide parser with callback

[Nathan Fontenot <nfont@linux.vnet.ibm.com>]

On 05/22/2018 11:37 AM, Michael Bringmann wrote:
> This patch provides a common parse function for the ibm,drc-info
> property that can be modified by a callback function.  The caller
> provides a pointer to the function and a pointer to their unique
> data, and the parser provides the current lmb set from the struct.
> The callback function may return codes indicating that the parsing
> is complete, or should continue, along with an error code that may
> be returned to the caller.
> 
> Signed-off-by: Michael Bringmann <mwb@linux.vnet.ibm.com>
> Fixes: 3f38000eda48 ("powerpc/firmware: Add definitions for new drc-info firmwar
> e feature" -- end of patch series applied to powerpc next)
> ---
> Changes in V4:
>   -- Update code to account for latest kernel checkins.
>   -- Rebased to 4.17-rc5 kernel
>   -- Some patch cleanup including file combination
> ---
>  arch/powerpc/include/asm/prom.h             |    7 +++++
>  arch/powerpc/platforms/pseries/of_helpers.c |   37 +++++++++++++++++++++++++++
>  2 files changed, 44 insertions(+)
> 
> diff --git a/arch/powerpc/include/asm/prom.h b/arch/powerpc/include/asm/prom.h
> index b04c5ce..2e947b3 100644
> --- a/arch/powerpc/include/asm/prom.h
> +++ b/arch/powerpc/include/asm/prom.h
> @@ -94,6 +94,13 @@ struct of_drc_info {
>  extern int of_read_drc_info_cell(struct property **prop,
>  			const __be32 **curval, struct of_drc_info *data);
> 
> +extern int drc_info_parser(struct device_node *dn,
> +			int (*usercb)(struct of_drc_info *drc,
> +					void *data,
> +					void *optional_data,

The optional_data parameter to the callback routine doesn't seem to be used.

-Nathan

> +					int *ret_code),
> +			char *opt_drc_type,
> +			void *data);
> 
>  /*
>   * There are two methods for telling firmware what our capabilities are.
> diff --git a/arch/powerpc/platforms/pseries/of_helpers.c b/arch/powerpc/platforms/pseries/of_helpers.c
> index 11b2ef1..a588ee6 100644
> --- a/arch/powerpc/platforms/pseries/of_helpers.c
> +++ b/arch/powerpc/platforms/pseries/of_helpers.c
> @@ -6,6 +6,9 @@
>  #include <asm/prom.h>
> 
>  #include "of_helpers.h"
> +#include "pseries.h"
> +
> +#define	MAX_DRC_NAME_LEN 64
> 
>  /**
>   * pseries_of_derive_parent - basically like dirname(1)
> @@ -87,3 +90,37 @@ int of_read_drc_info_cell(struct property **prop, const __be32 **curval,
>  	return 0;
>  }
>  EXPORT_SYMBOL(of_read_drc_info_cell);
> +
> +int drc_info_parser(struct device_node *dn,
> +		int (*usercb)(struct of_drc_info *drc,
> +				void *data,
> +				void *optional_data,
> +				int *ret_code),
> +		char *opt_drc_type,
> +		void *data)
> +{
> +	struct property *info;
> +	unsigned int entries;
> +	struct of_drc_info drc;
> +	const __be32 *value;
> +	int j, done = 0, ret_code = -EINVAL;
> +
> +	info = of_find_property(dn, "ibm,drc-info", NULL);
> +	if (info == NULL)
> +		return -EINVAL;
> +
> +	value = info->value;
> +	entries = of_read_number(value++, 1);
> +
> +	for (j = 0, done = 0; (j < entries) && (!done); j++) {
> +		of_read_drc_info_cell(&info, &value, &drc);
> +
> +		if (opt_drc_type && strcmp(opt_drc_type, drc.drc_type))
> +			continue;
> +
> +		done = usercb(&drc, data, NULL, &ret_code);
> +	}
> +
> +	return ret_code;
> +}
> +EXPORT_SYMBOL(drc_info_parser);
>