From: Ladislav Michl <ladis@linux-mips.org>
Date: Fri, 23 Feb 2018 10:15:01 +0000 (+0100)
Subject: clocksource: timer-ti-dm: Check prescaler value
X-Git-Url: http://git.cdn.openwrt.org/?a=commitdiff_plain;h=58a54f03e73d67432216931854363e4ba15839b9;p=openwrt%2Fstaging%2Fblogic.git

clocksource: timer-ti-dm: Check prescaler value

Invalid value silently disables use of the prescaler.
Use -1 explicitely for that purpose and error out on
invalid value.

Signed-off-by: Ladislav Michl <ladis@linux-mips.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>
---

diff --git a/drivers/clocksource/timer-ti-dm.c b/drivers/clocksource/timer-ti-dm.c
index 6abe5ab553ce..4cce6b224b87 100644
--- a/drivers/clocksource/timer-ti-dm.c
+++ b/drivers/clocksource/timer-ti-dm.c
@@ -663,13 +663,13 @@ static int omap_dm_timer_set_prescaler(struct omap_dm_timer *timer,
 {
 	u32 l;
 
-	if (unlikely(!timer))
+	if (unlikely(!timer) || prescaler < -1 || prescaler > 7)
 		return -EINVAL;
 
 	omap_dm_timer_enable(timer);
 	l = omap_dm_timer_read_reg(timer, OMAP_TIMER_CTRL_REG);
 	l &= ~(OMAP_TIMER_CTRL_PRE | (0x07 << 2));
-	if (prescaler >= 0x00 && prescaler <= 0x07) {
+	if (prescaler >= 0) {
 		l |= OMAP_TIMER_CTRL_PRE;
 		l |= prescaler << 2;
 	}