From f45c56af83eb79d8c6f7b68d4c25df3b65d6de6a Mon Sep 17 00:00:00 2001
From: Uwe Bonnes <bon@elektron.ikp.physik.tu-darmstadt.de>
Date: Sat, 28 Nov 2020 17:40:37 +0100
Subject: [PATCH] adiv5/swdp: Check early for valid DP idcode.

---
 src/target/adiv5.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/target/adiv5.c b/src/target/adiv5.c
index d6eafe9..8ab2a25 100644
--- a/src/target/adiv5.c
+++ b/src/target/adiv5.c
@@ -614,6 +614,12 @@ ADIv5_AP_t *adiv5_new_ap(ADIv5_DP_t *dp, uint8_t apsel)
 
 void adiv5_dp_init(ADIv5_DP_t *dp)
 {
+	/* Check IDCODE for a valid designer*/
+	if ((dp->idcode & 0xfff) == 0) {
+		DEBUG_WARN("Invalid DP idcode %08" PRIx32 "\n", dp->idcode);
+		free(dp);
+		return;
+	}
 	DEBUG_INFO("DPIDR 0x%08" PRIx32 " (v%d %srev%d)\n", dp->idcode,
 			   (dp->idcode >> 12) & 0xf,
 			   (dp->idcode & 0x10000) ? "MINDP " : "", dp->idcode >> 28);