From b795cb7ef4634bc782d557846b69da66bf36804f Mon Sep 17 00:00:00 2001
From: dragonmux <git@dragonmux.network>
Date: Mon, 8 Aug 2022 05:42:03 +0100
Subject: [PATCH] samd: Added an errata workaround for the SAMD11 DFLL48M which
 can have issues if left unrequested before configuration.

---
 src/target/samd.c | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/src/target/samd.c b/src/target/samd.c
index c9659e3..84a2531 100644
--- a/src/target/samd.c
+++ b/src/target/samd.c
@@ -298,6 +298,22 @@ static void samd20_revB_halt_resume(target *t, bool step)
 		target_mem_write32(t, SAMD_DSU_CTRLSTAT, SAMD_STATUSA_CRSTEXT);
 }
 
+/*
+ * Release the target from extended reset before running the normal cortexm_attach routine.
+ * This prevents tripping up over errata ref 9905
+ *
+ * Only required for SAM D11 silicon.
+ */
+static bool samd11_attach(target *t)
+{
+	/* Exit extended reset */
+	if (target_mem_read32(t, SAMD_DSU_CTRLSTAT) & SAMD_STATUSA_CRSTEXT)
+		/* Write bit to clear from extended reset */
+		target_mem_write32(t, SAMD_DSU_CTRLSTAT, SAMD_STATUSA_CRSTEXT);
+
+	return cortexm_attach(t);
+}
+
 /*
  * Overload the default cortexm attach for when the samd is protected.
  *
@@ -505,6 +521,12 @@ bool samd_probe(target *t)
 		 */
 		t->detach      = samd20_revB_detach;
 		t->halt_resume = samd20_revB_halt_resume;
+	} else if (samd.series == 11) {
+		/*
+		 * Attach routine that checks for an extended reset and releases it.
+		 * This works around Errata 38.2.5 ref 9905
+		 */
+		t->attach = samd11_attach;
 	}
 
 	if (protected) {