On Wed, Oct 20, 2010 at 02:45:13PM -0700, John Bonesio wrote:
> Changes to allow us to specify a node by it's path. A path can be used in
> place of a label.
>
> This is particularly useful when overriding existing nodes.
> This way we don't have to label every possible node in a device tree we know
> is a base device tree for a class of systems, and we know the tree will be
> modified for the specific systems.
>
> Signed-off-by: John Bonesio <[email protected]>
As already mentioned, but I'm reposting here for the list archive
record, this syntax conflicts with existing convention for referencing
nodes by names defined in the /aliases node.
One more comment below.
> ---
>
> dtc-lexer.l | 26 ++++++++++++++++++++++----
> dtc-parser.y | 10 ++++------
> livetree.c | 20 +++++++++++++++++++-
> 3 files changed, 45 insertions(+), 11 deletions(-)
>
> diff --git a/dtc-lexer.l b/dtc-lexer.l
> index 80a886a..216a3d2 100644
> --- a/dtc-lexer.l
> +++ b/dtc-lexer.l
> @@ -115,13 +115,31 @@ static int pop_input_file(void);
> return DT_LITERAL;
> }
>
> -<*>\&{LABEL} { /* label reference */
> - DPRINT("Ref: %s\n", yytext+1);
> - yylval.labelref = xstrdup(yytext+1);
> +
> +<*>\&{LABEL} { /* label reference without the braces*/
> + DPRINT("Ref: %s\n", yytext+1);
> + yylval.labelref = xstrdup(yytext+1);
> + return DT_REF;
> + }
> +
> +<*>"&{"{LABEL}{PATHCHAR}*\} { /* label and/or path refererence with braces */
> + /*
> + * Possibly this could be parsed by the parser rather
> + * than as a lexical element.
> + *
> + * What is intended here is to support the following
> + * type of references:
> + * a) &{/path/to/the/node/reference}
> + * b) &{label}
> + * c) &{label/path/from/labeled/node/to/reference}
> + */
> + yytext[yyleng-1] = '\0';
> + DPRINT("Ref: %s\n", yytext+2);
> + yylval.labelref = xstrdup(yytext+2);
> return DT_REF;
> }
>
> -"&{/"{PATHCHAR}+\} { /* new-style path reference */
> +<*>"&{/"{PATHCHAR}+\} { /* new-style path reference (with
> braces) */
> yytext[yyleng-1] = '\0';
> DPRINT("Ref: %s\n", yytext+2);
> yylval.labelref = xstrdup(yytext+2);
> diff --git a/dtc-parser.y b/dtc-parser.y
> index 1ba0478..0a74c86 100644
> --- a/dtc-parser.y
> +++ b/dtc-parser.y
> @@ -132,24 +132,22 @@ devicetree:
> }
> | devicetree DT_REF nodedef
> {
> - struct node *target;
> + struct node *target = get_node_by_ref($1, $2);
>
> - target = get_node_by_label($1, $2);
> if (target)
> merge_nodes(target, $3);
> else
> - print_error("label, '%s' not found", $2);
> + print_error("label or path, '%s', not found",
> $2);
For clarity, the above hunk should be in a separate patch applied
between patches #1 and #2. That will avoid having one patch introduce
the DT_REMOVENODE hunk below, and then immediately modify it again in
this patch. The switch to get_node_by_ref() is useful even without
the label+path syntax, and it should also include a matching testcase.
> $$ = $1;
> }
> | devicetree DT_REMOVENODE DT_REF ';'
> {
> - struct node *target;
> + struct node *target = get_node_by_ref($1, $3);
>
> - target = get_node_by_label($1, $3);
> if (target)
> remove_child(target->parent, target);
> else
> - print_error("label, '%s' not found", $3);
> + print_error("label or path, '%s', not found",
> $3);
> }
> ;
>
> diff --git a/livetree.c b/livetree.c
> index 21a4c48..bf8796b 100644
> --- a/livetree.c
> +++ b/livetree.c
> @@ -429,10 +429,28 @@ struct node *get_node_by_phandle(struct node *tree,
> cell_t phandle)
>
> struct node *get_node_by_ref(struct node *tree, const char *ref)
> {
> + struct node *node;
> +
> if (ref[0] == '/')
> return get_node_by_path(tree, ref);
> - else
> + else {
> + /*
> + * Support finding a node reference that is rooted by
> + * a label reference.
> + *
> + * References rooted by a label have a '/' in them.
> + */
> + char *p = strchr(ref, '/');
> +
> + if (p) {
> + *p = '\0';
> + node = get_node_by_label(tree, ref);
> + *p = '/';
> + return get_node_by_path(node, p+1);
> + }
> +
> return get_node_by_label(tree, ref);
> + }
> }
>
> cell_t get_node_phandle(struct node *root, struct node *node)
>
_______________________________________________
devicetree-discuss mailing list
[email protected]
https://lists.ozlabs.org/listinfo/devicetree-discuss
