Re: [Minios-devel] [UNIKRAFT PATCHv2 7/8] lib/fdt: Introduce fdt_node_offset_by_compatible_list helper

[Julien Grall <julien.grall@xxxxxxx>]

Hi,

On 11/03/2019 09:14, Jia He wrote:
> From: Jianyong Wu <jianyong.wu@xxxxxxx>
> For most of devices that will use the device tree will have one
> or more compatible strings. This helper will avoid implement a
> function to match compatible list everywhere.
>
> Jira: ENTOS-860
What is it for?

> Signed-off-by: Wei Chen <wei.chen@xxxxxxx>
> Signed-off-by: Jianyong Wu <jianyong.wu@xxxxxxx>
> Signed-off-by: Jia He <justin.he@xxxxxxx>
> ---
>   lib/fdt/exportsyms.uk    |  1 +
>   lib/fdt/fdt_ro.c         | 15 +++++++++++++++
>   lib/fdt/include/libfdt.h | 27 +++++++++++++++++++++++++++
>   3 files changed, 43 insertions(+)
>
> diff --git a/lib/fdt/exportsyms.uk b/lib/fdt/exportsyms.uk
> index bdef33c..a5ecf7c 100644
> --- a/lib/fdt/exportsyms.uk
> +++ b/lib/fdt/exportsyms.uk
> @@ -64,3 +64,4 @@ fdt_getprop_u32_by_offset
>   fdt_interrupt_cells
>   fdt_get_address
>   fdt_get_interrupt
> +fdt_node_offset_by_compatible_list
> diff --git a/lib/fdt/fdt_ro.c b/lib/fdt/fdt_ro.c
> index 9afede3..161928e 100644
> --- a/lib/fdt/fdt_ro.c
> +++ b/lib/fdt/fdt_ro.c
> @@ -741,3 +741,18 @@ int fdt_node_offset_by_compatible(const void *fdt, int 
> startoffset,
>   
>   	return offset; /* error from fdt_next_node() */
>   }
> +
> +int fdt_node_offset_by_compatible_list(const void *fdt, int startoffset,
> +                                 const char *compatibles[], int size)
As you pass an array of string, you can avoid passing the size by mandating the 
array to finish with NULL.
> +{
> +       int idx, offset;
> +
> +       for (idx = 0; idx < size; idx++) {
> +               offset = fdt_node_offset_by_compatible(fdt, startoffset,
> +                                 compatibles[idx]);
> +               if (offset >= 0)
> +                       return offset;
> +       }
> +
> +       return FDT_ERR_NOTFOUND;
> +}
> diff --git a/lib/fdt/include/libfdt.h b/lib/fdt/include/libfdt.h
> index d546b81..b45fe0b 100644
> --- a/lib/fdt/include/libfdt.h
> +++ b/lib/fdt/include/libfdt.h
> @@ -991,6 +991,33 @@ int fdt_node_check_compatible(const void *fdt, int 
> nodeoffset,
>   int fdt_node_offset_by_compatible(const void *fdt, int startoffset,
>                                   const char *compatible);
>   
> +/**
> + * fdt_node_offset_by_compatible_list - find nodes with a given
> + *                                     'compatible' list value
> + * @fdt: pointer to the device tree blob
> + * @startoffset: only find nodes after this offset
> + * @compatibles: a list of 'compatible' string to match against
> + * @size: compatible list size
> + *
> + * fdt_node_offset_by_compatible_list() returns the offset of the
> + * first matched node after startoffset, which has a 'compatible'
> + * property which lists the given compatible string; or if
> + * startoffset is -1, the very first such node in the tree.
> + *
> + * returns:
> + *     structure block offset of the located node (>= 0, >startoffset),
> + *              on success
> + *     -FDT_ERR_NOTFOUND, no node matching the criterion exists in the
> + *             tree after startoffset
> + *     -FDT_ERR_BADOFFSET, nodeoffset does not refer to a BEGIN_NODE tag
> + *     -FDT_ERR_BADMAGIC,
> + *     -FDT_ERR_BADVERSION,
> + *     -FDT_ERR_BADSTATE,
> + *     -FDT_ERR_BADSTRUCTURE, standard meanings
> + */
> +int fdt_node_offset_by_compatible_list(const void *fdt, int startoffset,
> +                                 const char *compatibles[], int size);
> +
>   /**
>    * fdt_stringlist_contains - check a string list property for a string
>    * @strlist: Property containing a list of strings to check
Cheers,

--
Julien Grall

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