mmc: sdhci-s3c: Do not allow frequencies higher than requested

This patch modifies sdhci_s3c_consider_clock() to fail if bus clock
being considered can not provide frequency lower or equal requested,
instead of returning the lowest supported.
Signed-off-by: Tomasz Figa <tomasz.figa@gmail.com>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Acked-by: Heiko Stuebner <heiko@sntech.de>
Tested-by: Jaehoon Chung <jh80.chung@samsung.com>
Acked-by; Jaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: Chris Ball <chris@printf.net>

drivers/mmc/host/sdhci-s3c.c

@@ -126,11 +126,18 @@ static unsigned int sdhci_s3c_consider_clock(struct sdhci_s3c *ourhost,
 
 	rate = ourhost->clk_rates[src];
 
-	for (shift = 0; shift < 8; ++shift) {
+	for (shift = 0; shift <= 8; ++shift) {
 		if ((rate >> shift) <= wanted)
 			break;
 	}
 
+	if (shift > 8) {
+		dev_dbg(&ourhost->pdev->dev,
+			"clk %d: rate %ld, min rate %lu > wanted %u\n",
+			src, rate, rate / 256, wanted);
+		return UINT_MAX;
+	}
+
 	dev_dbg(&ourhost->pdev->dev, "clk %d: rate %ld, want %d, got %ld\n",
 		src, rate, wanted, rate >> shift);