[PATCH] dtc: introduce label relative path references
Patrice CHOTARD
patrice.chotard at foss.st.com
Fri Mar 28 18:21:22 CET 2025
On 3/28/25 18:06, Peter Robinson wrote:
> On Fri, 28 Mar 2025 at 16:52, Patrice Chotard <patrice.chotard at foss.st.com>
> wrote:
>
>> Since introduction of OF_UPSTREAM flag, U-Boot's dtc must be able
>> to compile Kernel's device tree.
>>
>> Since kernel commit 7de129f5389b ("ARM: dts: stm32: stm32mp151a-prtt1l:
>> Fix QSPI configuration"), label relative path references has been
>> introduced. These label relative path references is not supported
>> by current U-Boot dtc version 1.5.0: (see mailing list discussion [1]).
>>
>> In order to support such label relative patch references
>> adds following commit from upstream DTC tree:
>>
>
> Maybe we need to rebase to the latest upstream dtc, I'm not sure pulling in
> a random set of bits from upstream is the right way to do things as it's
> brings things selectively which may bring along other issues.
Hi Peter
Initially it was expected to migrate to dtc 1.7.1 as proposed by Tom,
but as explained here [1] it has huge impacts on several U-Boot components
mainly due to DT header alignment on 8 bytes (even if some DT check can
be bypassed using FDT_ASSUME_MASK, i am not sure it's a good option).
I have spent time to investigate some issue raised by U-Boot CI-Build and
it's a huge time consuming task, more than expected.
Thanks
Patrice
>
>
>> commit 651410e54cb9 ("util: introduce xstrndup helper")
>> commit ec7986e682cf ("dtc: introduce label relative path references")
>>
>> [1] https://lore.kernel.org/all/20250115144428.GZ3476@bill-the-cat/T/
>>
>> Signed-off-by: Patrice Chotard <patrice.chotard at foss.st.com>
>> Cc: Tom Rini <trini at konsulko.com>
>> Cc: Simon Glass <sjg at chromium.org>
>> ---
>>
>> scripts/dtc/dtc-lexer.l | 2 +-
>> scripts/dtc/dtc-parser.y | 13 +++++++++++++
>> scripts/dtc/livetree.c | 33 ++++++++++++++++++++++++++++++---
>> scripts/dtc/util.c | 11 +++++++++++
>> scripts/dtc/util.h | 1 +
>> 5 files changed, 56 insertions(+), 4 deletions(-)
>>
>> diff --git a/scripts/dtc/dtc-lexer.l b/scripts/dtc/dtc-lexer.l
>> index d3694d6cf20..d34e1b04220 100644
>> --- a/scripts/dtc/dtc-lexer.l
>> +++ b/scripts/dtc/dtc-lexer.l
>> @@ -215,7 +215,7 @@ static void PRINTF(1, 2) lexical_error(const char
>> *fmt, ...);
>> return DT_REF;
>> }
>>
>> -<*>"&{/"{PATHCHAR}*\} { /* new-style path reference */
>> +<*>"&{"{PATHCHAR}*\} { /* new-style path reference */
>> yytext[yyleng-1] = '\0';
>> DPRINT("Ref: %s\n", yytext+2);
>> yylval.labelref = xstrdup(yytext+2);
>> diff --git a/scripts/dtc/dtc-parser.y b/scripts/dtc/dtc-parser.y
>> index 011a5b25539..b3b9c83873d 100644
>> --- a/scripts/dtc/dtc-parser.y
>> +++ b/scripts/dtc/dtc-parser.y
>> @@ -34,6 +34,12 @@ extern void yyerror(char const *s);
>>
>> extern struct dt_info *parser_output;
>> extern bool treesource_error;
>> +
>> +static bool is_ref_relative(const char *ref)
>> +{
>> + return ref[0] != '/' && strchr(&ref[1], '/');
>> +}
>> +
>> %}
>>
>> %union {
>> @@ -176,12 +182,17 @@ devicetree:
>> */
>> if (!($<flags>-1 & DTSF_PLUGIN))
>> ERROR(&@2, "Label or path %s not found",
>> $1);
>> + else if (is_ref_relative($1))
>> + ERROR(&@2, "Label-relative reference %s
>> not supported in plugin", $1);
>> $$ = add_orphan_node(name_node(build_node(NULL,
>> NULL), ""), $2, $1);
>> }
>> | devicetree DT_LABEL DT_REF nodedef
>> {
>> struct node *target = get_node_by_ref($1, $3);
>>
>> + if (($<flags>-1 & DTSF_PLUGIN) &&
>> is_ref_relative($3))
>> + ERROR(&@2, "Label-relative reference %s
>> not supported in plugin", $3);
>> +
>> if (target) {
>> add_label(&target->labels, $2);
>> merge_nodes(target, $4);
>> @@ -197,6 +208,8 @@ devicetree:
>> * so $-1 is what we want (plugindecl)
>> */
>> if ($<flags>-1 & DTSF_PLUGIN) {
>> + if (is_ref_relative($2))
>> + ERROR(&@2, "Label-relative
>> reference %s not supported in plugin", $2);
>> add_orphan_node($1, $3, $2);
>> } else {
>> struct node *target = get_node_by_ref($1,
>> $2);
>> diff --git a/scripts/dtc/livetree.c b/scripts/dtc/livetree.c
>> index ba06ef348be..4cfc2adccdd 100644
>> --- a/scripts/dtc/livetree.c
>> +++ b/scripts/dtc/livetree.c
>> @@ -583,12 +583,39 @@ 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 *target = tree;
>> + const char *label = NULL, *path = NULL;
>> +
>> if (streq(ref, "/"))
>> return tree;
>> - else if (ref[0] == '/')
>> - return get_node_by_path(tree, ref);
>> +
>> + if (ref[0] == '/')
>> + path = ref;
>> else
>> - return get_node_by_label(tree, ref);
>> + label = ref;
>> +
>> + if (label) {
>> + const char *slash = strchr(label, '/');
>> + char *buf = NULL;
>> +
>> + if (slash) {
>> + buf = xstrndup(label, slash - label);
>> + label = buf;
>> + path = slash + 1;
>> + }
>> +
>> + target = get_node_by_label(tree, label);
>> +
>> + free(buf);
>> +
>> + if (!target)
>> + return NULL;
>> + }
>> +
>> + if (path)
>> + target = get_node_by_path(target, path);
>> +
>> + return target;
>> }
>>
>> cell_t get_node_phandle(struct node *root, struct node *node)
>> diff --git a/scripts/dtc/util.c b/scripts/dtc/util.c
>> index 23334d39bb6..25d4db1e8c2 100644
>> --- a/scripts/dtc/util.c
>> +++ b/scripts/dtc/util.c
>> @@ -46,6 +46,17 @@ char *xstrdup(const char *s)
>> return d;
>> }
>>
>> +char *xstrndup(const char *s, size_t n)
>> +{
>> + size_t len = strnlen(s, n) + 1;
>> + char *d = xmalloc(len);
>> +
>> + memcpy(d, s, len - 1);
>> + d[len - 1] = '\0';
>> +
>> + return d;
>> +}
>> +
>> /* based in part from (3) vsnprintf */
>> int xasprintf(char **strp, const char *fmt, ...)
>> {
>> diff --git a/scripts/dtc/util.h b/scripts/dtc/util.h
>> index 211d584435d..23e32962385 100644
>> --- a/scripts/dtc/util.h
>> +++ b/scripts/dtc/util.h
>> @@ -70,6 +70,7 @@ static inline void *xrealloc(void *p, size_t len)
>> }
>>
>> extern char *xstrdup(const char *s);
>> +extern char *xstrndup(const char *s, size_t len);
>>
>> extern int PRINTF(2, 3) xasprintf(char **strp, const char *fmt, ...);
>> extern char *join_path(const char *path, const char *name);
>> --
>> 2.25.1
>>
>>
>
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