program_loading: make types a mask, make unknown type a non-zero

This will allow loading of programs that are more than one type,
e.g. ramstage type might now be a stage or payload.

Further, unknown types of 0 are dangerous, make it a real value.

Change-Id: Ieb4eeb7c5934bddd9046ece8326342db0d76363c
Signed-off-by: Ronald G. Minnich <rminnich@gmail.com>
Reviewed-on: https://review.coreboot.org/26242
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Philipp Deppenwiese <zaolin.daisuki@gmail.com>

src/include/program_loading.h

@@ -26,15 +26,22 @@ enum {
 	SEG_FINAL = 1 << 0,
 };
 
+// The prog_type is a bit mask, so that in searches one can find, e.g.,
+// a file with a given name that is either a payload or a ramstage.
+// The PROG_UNKNOWN should not have any bits set that match a valid
+// type, and for the sake of sanity, let's keep the high order bit out of it.
+// The current value allows for 16 file types. This is a change from before,
+// where we could have 2^32-1 different types. On a guess, it seems 16 should
+// be enough. We started with 3 and are up to 6 twelve years later.
 enum prog_type {
-	PROG_UNKNOWN,
-	PROG_VERSTAGE,
-	PROG_ROMSTAGE,
-	PROG_RAMSTAGE,
-	PROG_REFCODE,
-	PROG_PAYLOAD,
-	PROG_BL31,
-	PROG_BL32,
+	PROG_UNKNOWN = 0x7bba0000,
+	PROG_VERSTAGE = 1 << 0,
+	PROG_ROMSTAGE = 1 << 1,
+	PROG_RAMSTAGE = 1 << 2,
+	PROG_REFCODE = 1 << 3,
+	PROG_PAYLOAD = 1 << 4,
+	PROG_BL31 = 1 << 5,
+	PROG_BL32 = 1 << 6,
 };
 
 /*