开发环境：win10 64位 + VMware12 + Ubuntu14.04 32位

工具链：linaro提供的gcc-linaro-6.1.1-2016.08-x86_64_arm-linux-gnueabi

要移植的u-boot版本：u-boot-2016-11

Tiny4412开发板硬件版本为：

  底板：  Tiny4412SDK 1312B

  核心板：Tiny4412 - 1306

1，原理图

查看tiny4412SDK-1312B -Schematic.pdf

可看出，底板使用UART0作为外接串口

2、uart0初始化步骤

1. 选择UART的时钟源
2. 将所涉及的UART通道管脚设为UART功能
3. 设置波特率：UBRDIVn寄存器(UART BAUD RATE DIVISOR)、UFRACVALn寄存器
4. 设置传输格式：ULCONn寄存器(UART LINE CONTROL)
5. 设置UART工作模式：UCONn寄存器(UART CONTROL)
6. UFCONn寄存器(UART FIFO CONTROL)、UFSTATn寄存器(UART FIFO STATUS)

3、使用Tiny4412 Debug 串口uart0代码设置

diff --git a/arch/arm/dts/exynos4412-tiny4412.dts b/arch/arm/dts/exynos4412-tiny
index 4810202..3e057dc 100644
--- a/arch/arm/dts/exynos4412-tiny4412.dts
+++ b/arch/arm/dts/exynos4412-tiny4412.dts
@@ -14,74 +14,16 @@
        model = "Tiny4412 based on Exynos4412";
        compatible = "samsung,tiny4412", "samsung,exynos4412";

-       aliases {
-               i2c0 = "/i2c@13860000";
-               i2c1 = "/i2c@13870000";
-               i2c2 = "/i2c@13880000";
-               i2c3 = "/i2c@13890000";
-               i2c4 = "/i2c@138a0000";
-               i2c5 = "/i2c@138b0000";
-               i2c6 = "/i2c@138c0000";
-               i2c7 = "/i2c@138d0000";
-               serial0 = "/serial@13800000";
-               console = "/serial@13810000";
-               mmc2 = "/sdhci@12530000";
-               mmc4 = "/dwmmc@12550000";
-       };
-
-       i2c@13860000 {
-               samsung,i2c-sda-delay = <100>;
-               samsung,i2c-slave-addr = <0x10>;
-               samsung,i2c-max-bus-freq = <100000>;
-               status = "okay";
+  chosen {
+      stdout-path = "serial0";
+    };

+  aliases {
+      serial0 = "/serial@13800000";
+      console = "/serial@13800000";
        };

-       serial@13810000 {
+  serial0:serial@13810000 {
                status = "okay";
        };
-
-       sdhci@12510000 {
-               status = "disabled";
-       };
-
-       sdhci@12520000 {
-               status = "disabled";
-       };
-
-       sdhci@12530000 {
-               samsung,bus-width = <4>;
-               samsung,timing = <1 2 3>;
-               cd-gpios = <&gpk2 2 0>;
-       };
-
-       sdhci@12540000 {
-               status = "disabled";
-       };
-
-       dwmmc@12550000 {
-               samsung,bus-width = <8>;
-               samsung,timing = <2 1 0>;
-               samsung,removable = <0>;
-               fifoth_val = <0x203f0040>;
-               bus_hz = <400000000>;
-               div = <0x3>;
-               index = <4>;
-       };
-
-       ehci@12580000 {
-               compatible = "samsung,exynos-ehci";
-               reg = <0x12580000 0x100>;
-               #address-cells = <1>;
-               #size-cells = <1>;
-               phy {
-                       compatible = "samsung,exynos-usb-phy";
-                       reg = <0x125B0000 0x100>;
-               };
-       };
-
-       emmc-reset {
-               compatible = "samsung,emmc-reset";
-               reset-gpio = <&gpk1 2 0>;
-       };
 };

diff --git a/arch/arm/mach-exynos/Makefile b/arch/arm/mach-exynos/Makefile
index 5889802..5575adf 100644
--- a/arch/arm/mach-exynos/Makefile
+++ b/arch/arm/mach-exynos/Makefile
@@ -15,7 +15,7 @@ ifdef CONFIG_SPL_BUILD
 obj-$(CONFIG_EXYNOS5)  += clock_init_exynos5.o
 obj-$(CONFIG_EXYNOS5)  += dmc_common.o dmc_init_ddr3.o
 obj-$(CONFIG_EXYNOS4210)+= dmc_init_exynos4.o clock_init_exynos4.o
-obj-$(CONFIG_EXYNOS4412)+= dmc_init_exynos4412.o clock_init_exynos4412.o
+obj-$(CONFIG_EXYNOS4412)+= dmc_init_exynos4.o clock_init_exynos4412.o

 obj-y  += spl_boot.o tzpc.o
 obj-y  += lowlevel_init.o

diff --git a/arch/arm/mach-exynos/lowlevel_init.c b/arch/arm/mach-exynos/lowleve
index 1e090fd..c69be57 100644
--- a/arch/arm/mach-exynos/lowlevel_init.c
+++ b/arch/arm/mach-exynos/lowlevel_init.c
@@ -218,9 +218,15 @@ int do_lowlevel_init(void)
 #ifdef CONFIG_DEBUG_UART
 #if (defined(CONFIG_SPL_BUILD) && defined(CONFIG_SPL_SERIAL_SUPPORT)) ||      !defined(CONFIG_SPL_BUILD)
-               exynos_pinmux_config(PERIPH_ID_UART3, PINMUX_FLAG_NONE);
-               debug_uart_init();
+
+    #ifdef TINY4412
+        exynos_pinmux_config(PERIPH_ID_UART0, PINMUX_FLAG_NONE);
+    #else
+        exynos_pinmux_config(PERIPH_ID_UART3, PINMUX_FLAG_NONE);
+    #endif
+        debug_uart_init();
 #endif
+        printascii("UART0 init ... OK !!!\n\r");
 #endif
                mem_ctrl_init(actions & DO_MEM_RESET);
                tzpc_init();

diff --git a/configs/tiny4412_defconfig b/configs/tiny4412_defconfig
index ccc9fab..25c6bfb 100644
--- a/configs/tiny4412_defconfig
+++ b/configs/tiny4412_defconfig
@@ -37,3 +37,14 @@ CONFIG_OF_CONTROL=y
 #CONFIG_G_DNL_MANUFACTURER="Samsung"
 #CONFIG_G_DNL_VENDOR_NUM=0x04e8
 #CONFIG_G_DNL_PRODUCT_NUM=0x6601
+
+#DEBUG UART
+#
+CONFIG_DEBUG_UART=y
+CONFIG_SPL_SERIAL_SUPPORT=y
+CONFIG_SPL_GPIO_SUPPORT=y
+CONFIG_DEBUG_UART_S5P=y
+CONFIG_DEBUG_UART_BASE=0x13800000
+CONFIG_DEBUG_UART_CLOCK=100000000
+
+#

原文地址：https://www.cnblogs.com/chu-yi/p/10387604.html