--- zzzz-none-000/linux-3.10.107/arch/mips/kernel/csrc-ioasic.c	2017-06-27 09:49:32.000000000 +0000
+++ scorpion-7490-727/linux-3.10.107/arch/mips/kernel/csrc-ioasic.c	2021-02-04 17:41:59.000000000 +0000
@@ -12,12 +12,9 @@
  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  *  GNU General Public License for more details.
- *
- *  You should have received a copy of the GNU General Public License
- *  along with this program; if not, write to the Free Software
- *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 #include <linux/clocksource.h>
+#include <linux/sched_clock.h>
 #include <linux/init.h>
 
 #include <asm/ds1287.h>
@@ -37,13 +34,18 @@
 	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
 };
 
-void __init dec_ioasic_clocksource_init(void)
+static u64 notrace dec_ioasic_read_sched_clock(void)
+{
+	return ioasic_read(IO_REG_FCTR);
+}
+
+int __init dec_ioasic_clocksource_init(void)
 {
 	unsigned int freq;
 	u32 start, end;
-	int i = HZ / 10;
-
+	int i = HZ / 8;
 
+	ds1287_timer_state();
 	while (!ds1287_timer_state())
 		;
 
@@ -55,9 +57,18 @@
 
 	end = dec_ioasic_hpt_read(&clocksource_dec);
 
-	freq = (end - start) * 10;
+	freq = (end - start) * 8;
+
+	/* An early revision of the I/O ASIC didn't have the counter.  */
+	if (!freq)
+		return -ENXIO;
+
 	printk(KERN_INFO "I/O ASIC clock frequency %dHz\n", freq);
 
 	clocksource_dec.rating = 200 + freq / 10000000;
 	clocksource_register_hz(&clocksource_dec, freq);
+
+	sched_clock_register(dec_ioasic_read_sched_clock, 32, freq);
+
+	return 0;
 }