--- src/sys/kern/kern_todr.c.dist	2026-01-23 16:30:48.189998898 +0100
+++ src/sys/kern/kern_todr.c	2026-06-01 16:49:35.249972477 +0200
@@ -78,6 +78,7 @@
 #include <sys/device_calls.h>
 #include <sys/intr.h>
 #include <sys/kernel.h>
+#include <sys/kmem.h>
 #include <sys/mutex.h>
 #include <sys/rndsource.h>
 #include <sys/sdt.h>
@@ -86,11 +87,17 @@
 
 #include <dev/clock_subr.h>	/* hmm.. this should probably move to sys */
 
+struct todr_list {
+	todr_chip_handle_t todr_handle;
+	struct todr_list *todr_next;
+};
+
 static int todr_gettime(todr_chip_handle_t, struct timeval *);
 static int todr_settime(todr_chip_handle_t, struct timeval *);
 
 static kmutex_t todr_mutex;
-static todr_chip_handle_t todr_handle;
+static struct todr_list todr_head =
+	{ .todr_handle = NULL, .todr_next = NULL };
 static bool todr_initialized;
 
 /* The minimum reasonable RTC date before preposterousness */
@@ -179,6 +186,7 @@
 void
 todr_attach(todr_chip_handle_t todr)
 {
+	struct todr_list *todr_newp, *todr_iterp;
 
 	/*
 	 * todr_init() is called very early in main(), but this is
@@ -191,14 +199,24 @@
 		return;
 	}
 
-	todr_lock();
-	if (todr_handle) {
+	/* Initial entry is static, others allocated. */
+	if (todr_head.todr_handle == NULL) {
+		todr_lock();
+		todr_head.todr_handle = todr;
 		todr_unlock();
-		printf("todr_attach: TOD already configured\n");
-		return;
+	} else {
+		todr_newp = kmem_alloc(sizeof(struct todr_list),
+		    KM_SLEEP);
+		todr_newp->todr_next = NULL;
+		todr_lock();
+		todr_newp->todr_handle = todr;
+		todr_iterp = &todr_head;
+		while (todr_iterp->todr_next != NULL)
+			todr_iterp = todr_iterp->todr_next;
+		todr_iterp->todr_next = todr_newp;
+		todr_unlock();
+		printf("%s: secondary clock\n", device_xname(todr->todr_dev));
 	}
-	todr_handle = todr;
-	todr_unlock();
 }
 
 static bool timeset = false;
@@ -217,7 +235,10 @@
 	bool goodtime = false;
 	bool badrtc = false;
 	struct timespec ts;
-	struct timeval tv;
+	struct timeval tv, tv2;
+	struct todr_list *todr_iterp;
+	device_t t_dev;
+	time_t deltat;
 
 	KASSERT(todr_lock_owned());
 
@@ -246,22 +267,23 @@
 	/*
 	 * Some ports need to be supplied base in order to fabricate a time_t.
 	 */
-	if (todr_handle)
-		todr_handle->todr_base_time = base;
+	if (todr_head.todr_handle != NULL)
+		todr_head.todr_handle->todr_base_time = base;
 
 	memset(&tv, 0, sizeof(tv));
 
-	if ((todr_handle == NULL) ||
-	    (todr_gettime(todr_handle, &tv) != 0) ||
+	/* Note, that we use the first RTC for system time. */
+	if ((todr_head.todr_handle == NULL) ||
+	    (todr_gettime(todr_head.todr_handle, &tv) != 0) ||
 	    (tv.tv_sec < (PREPOSTEROUS_YEARS * SECS_PER_COMMON_YEAR))) {
 
-		if (todr_handle != NULL)
+		if (todr_head.todr_handle != NULL)
 			printf("WARNING: preposterous TOD clock time\n");
 		else
 			printf("WARNING: no TOD clock present\n");
 		badrtc = true;
 	} else {
-		time_t deltat = tv.tv_sec - base;
+		deltat = tv.tv_sec - base;
 
 		if (deltat < 0)
 			deltat = -deltat;
@@ -301,6 +323,29 @@
 		tv.tv_usec = 0;
 	}
 
+	/* Check other clocks, if any, against our time */
+	todr_iterp = &todr_head;
+	while ((todr_iterp = todr_iterp->todr_next) != NULL) {
+		if ((todr_iterp->todr_handle == NULL) || 
+		    (todr_gettime(todr_iterp->todr_handle, &tv2) != 0))
+			continue;
+		t_dev = todr_iterp->todr_handle->todr_dev;
+		if (tv2.tv_sec < (PREPOSTEROUS_YEARS * SECS_PER_COMMON_YEAR)) {
+			printf("WARNING: preposterous %s clock time\n",
+			    device_xname(t_dev));
+			deltat = 0;
+		} else {
+			deltat = tv.tv_sec - tv2.tv_sec;
+			rnd_add_data(NULL, &tv, sizeof(tv), 0);
+		}
+		if (deltat < -10)
+			printf("WARNING: %s clock lost %" PRId64 " seconds\n",
+			    device_xname(t_dev), deltat);
+		if (deltat > 10)
+			printf("WARNING: %s clock gained %" PRId64 " seconds\n",
+			    device_xname(t_dev), deltat);
+	}
+
 	timeset = true;
 
 	ts.tv_sec = tv.tv_sec;
@@ -315,13 +360,14 @@
 
 /*
  * todr_save_systime:
- *	Save the current system time back to the TOD clock.
+ *	Save the current system time back to the TOD clock(s).
  *	Must be called with the TODR lock held.
  */
 void
 todr_save_systime(void)
 {
 	struct timeval tv;
+	struct todr_list *todr_iterp;
 
 	KASSERT(todr_lock_owned());
 
@@ -338,9 +384,14 @@
 	if (tv.tv_sec == 0)
 		return;
 
-	if (todr_handle)
-		if (todr_settime(todr_handle, &tv) != 0)
-			printf("Cannot set TOD clock time\n");
+	todr_iterp = &todr_head;
+	do {
+		if ((todr_iterp->todr_handle != NULL) &&
+		    (todr_settime(todr_iterp->todr_handle, &tv) != 0))
+			printf("Cannot set %s TOD clock time\n",
+			    device_xname(todr_iterp->todr_handle->todr_dev));
+		todr_iterp = todr_iterp->todr_next;
+	} while (todr_iterp != NULL);
 }
 
 /*
--- src/sys/arch/sparc64/conf/GENERIC.dist	2026-06-04 15:59:46.000000000 +0200
+++ src/sys/arch/sparc64/conf/GENERIC	2026-06-04 16:01:00.229974214 +0200
@@ -840,6 +840,7 @@
 seeprom*	at iic? addr?	# i2c-at24c64 fru's
 pcagpio* 	at iic? addr?	# V210/V240 GPIO's
 pcf8574io* 	at iic? addr?	# E250 GPIO's
+dsrtc* 		at iic? addr?	# RSC clock found on V210/V240
 
 ### Other pseudo-devices