From: Michael Brown <mcb30@ipxe.org>
Date: Mon, 14 Apr 2025 10:32:17 +0000 (+0100)
Subject: [fdt] Provide fdt_strings() to read string list properties
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=c887de208fd18efd65e19d325e24e3365fce0570;p=thirdparty%2Fipxe.git

[fdt] Provide fdt_strings() to read string list properties

Signed-off-by: Michael Brown <mcb30@ipxe.org>
---

diff --git a/src/core/fdt.c b/src/core/fdt.c
index 199a53497..2ca41bc08 100644
--- a/src/core/fdt.c
+++ b/src/core/fdt.c
@@ -403,30 +403,59 @@ static int fdt_property ( struct fdt *fdt, unsigned int offset,
 }
 
 /**
- * Find string property
+ * Find strings property
  *
  * @v fdt		Device tree
  * @v offset		Starting node offset
  * @v name		Property name
+ * @v count		String count to fill in
  * @ret string		String property, or NULL on error
  */
-const char * fdt_string ( struct fdt *fdt, unsigned int offset,
-			  const char *name ) {
+const char * fdt_strings ( struct fdt *fdt, unsigned int offset,
+			   const char *name, unsigned int *count ) {
 	struct fdt_descriptor desc;
+	const char *data;
+	size_t len;
 	int rc;
 
+	/* Return a zero count on error */
+	*count = 0;
+
 	/* Find property */
 	if ( ( rc = fdt_property ( fdt, offset, name, &desc ) ) != 0 )
 		return NULL;
 
 	/* Check NUL termination */
-	if ( strnlen ( desc.data, desc.len ) == desc.len ) {
+	data = desc.data;
+	if ( desc.len && ( data[ desc.len - 1 ] != '\0' ) ) {
 		DBGC ( fdt, "FDT unterminated string property \"%s\"\n",
 		       name );
 		return NULL;
 	}
 
-	return desc.data;
+	/* Count number of strings */
+	for ( len = desc.len ; len-- ; ) {
+		if ( data[len] == '\0' )
+			(*count)++;
+	}
+
+	return data;
+}
+
+/**
+ * Find string property
+ *
+ * @v fdt		Device tree
+ * @v offset		Starting node offset
+ * @v name		Property name
+ * @ret string		String property, or NULL on error
+ */
+const char * fdt_string ( struct fdt *fdt, unsigned int offset,
+			  const char *name ) {
+	unsigned int count;
+
+	/* Find strings property */
+	return fdt_strings ( fdt, offset, name, &count );
 }
 
 /**
diff --git a/src/include/ipxe/fdt.h b/src/include/ipxe/fdt.h
index 7eec5cd88..1e05c9e2d 100644
--- a/src/include/ipxe/fdt.h
+++ b/src/include/ipxe/fdt.h
@@ -115,6 +115,8 @@ extern int fdt_path ( struct fdt *fdt, const char *path,
 		      unsigned int *offset );
 extern int fdt_alias ( struct fdt *fdt, const char *name,
 		       unsigned int *offset );
+extern const char * fdt_strings ( struct fdt *fdt, unsigned int offset,
+				  const char *name, unsigned int *count );
 extern const char * fdt_string ( struct fdt *fdt, unsigned int offset,
 				 const char *name );
 extern int fdt_u64 ( struct fdt *fdt, unsigned int offset, const char *name,