ARM: exynos: clock: modify the set_mmc_clk for exynos4

Modified the mmc_set_clock for eynos4.
The goal of this patch is that fsys-div register should be reset.
And retore the div-value, not using the value of lowlevel_init.
(For using SDMMC4, this patch is needs)

Signed-off-by: Jaehoon Chung <jh80.chung@samsung.com>
Tested-by: Lukasz Majewski <l.majewski@samsung.com>
Acked-by: Lukasz Majewski <l.majewski@samsung.com>
Signed-off-by: Minkyu Kang <mk7.kang@samsung.com>

arch/arm/cpu/armv7/exynos/clock.c

@@ -869,7 +869,7 @@ static void exynos4_set_mmc_clk(int dev_index, unsigned int div)
 {
 	struct exynos4_clock *clk =
 		(struct exynos4_clock *)samsung_get_base_clock();
-	unsigned int addr;
+	unsigned int addr, clear_bit, set_bit;
 
 	/*
 	 * CLK_DIV_FSYS1
@@ -877,20 +877,26 @@ static void exynos4_set_mmc_clk(int dev_index, unsigned int div)
 	 * CLK_DIV_FSYS2
 	 * MMC2_PRE_RATIO [15:8], MMC3_PRE_RATIO [31:24]
 	 * CLK_DIV_FSYS3
-	 * MMC4_PRE_RATIO [15:8]
+	 * MMC4_RATIO [3:0]
 	 */
 	if (dev_index < 2) {
 		addr = (unsigned int)&clk->div_fsys1;
-	}  else if (dev_index == 4) {
+		clear_bit = MASK_PRE_RATIO(dev_index);
+		set_bit = SET_PRE_RATIO(dev_index, div);
+	} else if (dev_index == 4) {
 		addr = (unsigned int)&clk->div_fsys3;
 		dev_index -= 4;
+		/* MMC4 is controlled with the MMC4_RATIO value */
+		clear_bit = MASK_RATIO(dev_index);
+		set_bit = SET_RATIO(dev_index, div);
 	} else {
 		addr = (unsigned int)&clk->div_fsys2;
 		dev_index -= 2;
+		clear_bit = MASK_PRE_RATIO(dev_index);
+		set_bit = SET_PRE_RATIO(dev_index, div);
 	}
 
-	clrsetbits_le32(addr, 0xff << ((dev_index << 4) + 8),
-			(div & 0xff) << ((dev_index << 4) + 8));
+	clrsetbits_le32(addr, clear_bit, set_bit);
 }
 
 /* exynos5: set the mmc clock */

arch/arm/include/asm/arch-exynos/clk.h

@@ -16,6 +16,11 @@
 #define BPLL	5
 #define RPLL	6
 
+#define MASK_PRE_RATIO(x)	(0xff << ((x << 4) + 8))
+#define MASK_RATIO(x)		(0xf << (x << 4))
+#define SET_PRE_RATIO(x, y)	((y & 0xff) << ((x << 4) + 8))
+#define SET_RATIO(x, y)		((y & 0xf) << (x << 4))
+
 enum pll_src_bit {
 	EXYNOS_SRC_MPLL = 6,
 	EXYNOS_SRC_EPLL,