From 74710b8316b40c9e3081c1014813867d4764796b Mon Sep 17 00:00:00 2001
From: Michael Brown <mcb30@ipxe.org>
Date: Mon, 28 Oct 2024 13:45:51 +0000
Subject: [PATCH] [fdt] Add ability to parse unsigned integer properties

Signed-off-by: Michael Brown <mcb30@ipxe.org>
---
 src/core/fdt.c         | 38 ++++++++++++++++++++++++++++++++++++++
 src/include/ipxe/fdt.h |  1 +
 2 files changed, 39 insertions(+)

diff --git a/src/core/fdt.c b/src/core/fdt.c
index f439422cf..b7289fd36 100644
--- a/src/core/fdt.c
+++ b/src/core/fdt.c
@@ -367,6 +367,44 @@ const char * fdt_string ( unsigned int offset, const char *name ) {
 	return desc.data;
 }
 
+/**
+ * Find integer property
+ *
+ * @v offset		Starting node offset
+ * @v name		Property name
+ * @v value		Integer value to fill in
+ * @ret rc		Return status code
+ */
+int fdt_u64 ( unsigned int offset, const char *name, uint64_t *value ) {
+	struct fdt_descriptor desc;
+	const uint8_t *data;
+	size_t remaining;
+	int rc;
+
+	/* Clear value */
+	*value = 0;
+
+	/* Find property */
+	if ( ( rc = fdt_property ( offset, name, &desc ) ) != 0 )
+		return rc;
+
+	/* Check range */
+	if ( desc.len > sizeof ( *value ) ) {
+		DBGC ( &fdt, "FDT oversized integer property \"%s\"\n", name );
+		return -ERANGE;
+	}
+
+	/* Parse value */
+	data = desc.data;
+	remaining = desc.len;
+	while ( remaining-- ) {
+		*value <<= 8;
+		*value |= *(data++);
+	}
+
+	return 0;
+}
+
 /**
  * Get MAC address from property
  *
diff --git a/src/include/ipxe/fdt.h b/src/include/ipxe/fdt.h
index 97efa100c..9b9b01b6c 100644
--- a/src/include/ipxe/fdt.h
+++ b/src/include/ipxe/fdt.h
@@ -96,6 +96,7 @@ struct fdt {
 extern int fdt_path ( const char *path, unsigned int *offset );
 extern int fdt_alias ( const char *name, unsigned int *offset );
 extern const char * fdt_string ( unsigned int offset, const char *name );
+extern int fdt_u64 ( unsigned int offset, const char *name, uint64_t *value );
 extern int fdt_mac ( unsigned int offset, struct net_device *netdev );
 extern int register_fdt ( const struct fdt_header *hdr );