dtc: Wrap phandle validity check

In several places we check for a returned phandle value to be valid,
for that it must not be 0 or "-1".

Wrap this check in a static inline function in dtc.h, and use ~0U instead
of -1 on the way, to keep everything in the unsigned realm.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Message-Id: <20210618172030.9684-4-andre.przywara@arm.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

1 files changed, 5 insertions, 0 deletions

diff --git a/dtc.h b/dtc.h
index 47664f2..cf2c6ac 100644
--- a/dtc.h
+++ b/dtc.h
@@ -51,6 +51,11 @@ extern int annotate;		/* annotate .dts with input source location */
 
 typedef uint32_t cell_t;
 
+static inline bool phandle_is_valid(cell_t phandle)
+{
+	return phandle != 0 && phandle != ~0U;
+}
+
 static inline uint16_t dtb_ld16(const void *p)
 {
 	const uint8_t *bp = (const uint8_t *)p;