ARM: S3C2443: handle unset armdiv values gracefully

The armdiv array may contain unset divider values.
Check the relevant value to prevent division by zero
errors. Also check for set nr_armdiv and armdivmask
before meddling with clkdiv0.
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>

arch/arm/plat-s3c24xx/s3c2443-clock.c

@@ -179,12 +179,17 @@ static unsigned long s3c2443_armclk_roundrate(struct clk *clk,
 	unsigned div;
 	int ptr;
 
+	if (!nr_armdiv)
+		return -EINVAL;
+
 	for (ptr = 0; ptr < nr_armdiv; ptr++) {
 		div = armdiv[ptr];
+		if (div) {
 			calc = parent / div;
 			if (calc <= rate && div < best)
 				best = div;
 		}
+	}
 
 	return parent / best;
 }
@@ -195,6 +200,9 @@ static unsigned long s3c2443_armclk_getrate(struct clk *clk)
 	unsigned long clkcon0;
 	int val;
 
+	if (!nr_armdiv || !armdivmask)
+		return -EINVAL;
+
 	clkcon0 = __raw_readl(S3C2443_CLKDIV0);
 	clkcon0 &= armdivmask;
 	val = clkcon0 >> S3C2443_CLKDIV0_ARMDIV_SHIFT;
@@ -211,14 +219,19 @@ static int s3c2443_armclk_setrate(struct clk *clk, unsigned long rate)
 	int ptr;
 	int val = -1;
 
+	if (!nr_armdiv || !armdivmask)
+		return -EINVAL;
+
 	for (ptr = 0; ptr < nr_armdiv; ptr++) {
 		div = armdiv[ptr];
+		if (div) {
 			calc = parent / div;
 			if (calc <= rate && div < best) {
 				best = div;
 				val = ptr;
 			}
 		}
+	}
 
 	if (val >= 0) {
 		unsigned long clkcon0;