ARM: AM43xx: EPOS_EVM: Add support for LPDDR2

AM4372 EPOS EVM has 1GB LPDDR2(Part no: MT42L256M32D2LG-25 WT:A)
Adding LPDDR2 init sequence and register details for the same.
Below is the brief description of LPDDR2 init sequence:
-> Configure VTP
-> Configure DDR IO settings
-> Disable initialization and refreshes until EMIF registers are programmed.
-> Program Timing registers
-> Program PHY control and Temp alert and ZQ config registers.
-> Enable initialization and refreshes and configure SDRAM CONFIG register
-> Wait till initialization is complete and the configure MR registers.

Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
diff --git a/arch/arm/cpu/armv7/am33xx/emif4.c b/arch/arm/cpu/armv7/am33xx/emif4.c
index adda650..d28fceb 100644
--- a/arch/arm/cpu/armv7/am33xx/emif4.c
+++ b/arch/arm/cpu/armv7/am33xx/emif4.c
@@ -48,6 +48,11 @@
 #ifdef CONFIG_AM33XX
 static struct ddr_ctrl *ddrctrl = (struct ddr_ctrl *)DDR_CTRL_ADDR;
 #endif
+#ifdef CONFIG_AM43XX
+static struct ddr_ctrl *ddrctrl = (struct ddr_ctrl *)DDR_CTRL_ADDR;
+static struct cm_device_inst *cm_device =
+				(struct cm_device_inst *)CM_DEVICE_INST;
+#endif
 
 #ifdef CONFIG_TI81XX
 void config_dmm(const struct dmm_lisa_map_regs *regs)
@@ -104,9 +109,24 @@
 	/* Set CKE to be controlled by EMIF/DDR PHY */
 	writel(DDR_CKE_CTRL_NORMAL, &ddrctrl->ddrckectrl);
 #endif
+#ifdef CONFIG_AM43XX
+	writel(readl(&cm_device->cm_dll_ctrl) & ~0x1, &cm_device->cm_dll_ctrl);
+	while ((readl(&cm_device->cm_dll_ctrl) && CM_DLL_READYST) == 0)
+		;
+	writel(0x0, &ddrctrl->ddrioctrl);
+
+	config_io_ctrl(ioregs);
+
+	/* Set CKE to be controlled by EMIF/DDR PHY */
+	writel(DDR_CKE_CTRL_NORMAL, &ddrctrl->ddrckectrl);
+#endif
+
 	/* Program EMIF instance */
 	config_ddr_phy(regs, nr);
 	set_sdram_timings(regs, nr);
-	config_sdram(regs, nr);
+	if (get_emif_rev(EMIF1_BASE) == EMIF_4D5)
+		config_sdram_emif4d5(regs, nr);
+	else
+		config_sdram(regs, nr);
 }
 #endif