mips: ath79: add AP121 reference board

This patch add board-level code and base DT for AP121.

Signed-off-by: Wills Wang <wills.wang@live.com>
[updated defconfig, enabled CONFIG_USE_PRIVATE_LIBGCC=y]
Signed-off-by: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
diff --git a/board/qca/ap121/ap121.c b/board/qca/ap121/ap121.c
new file mode 100644
index 0000000..d6c60fe
--- /dev/null
+++ b/board/qca/ap121/ap121.c
@@ -0,0 +1,50 @@
+/*
+ * Copyright (C) 2015-2016 Wills Wang <wills.wang@live.com>
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+
+#include <common.h>
+#include <asm/io.h>
+#include <asm/addrspace.h>
+#include <asm/types.h>
+#include <mach/ar71xx_regs.h>
+#include <mach/ddr.h>
+#include <debug_uart.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+#ifdef CONFIG_DEBUG_UART_BOARD_INIT
+void board_debug_uart_init(void)
+{
+	void __iomem *regs;
+	u32 val;
+
+	regs = map_physmem(AR71XX_GPIO_BASE, AR71XX_GPIO_SIZE,
+			   MAP_NOCACHE);
+
+	/*
+	 * GPIO9 as input, GPIO10 as output
+	 */
+	val = readl(regs + AR71XX_GPIO_REG_OE);
+	val &= ~AR933X_GPIO(9);
+	val |= AR933X_GPIO(10);
+	writel(val, regs + AR71XX_GPIO_REG_OE);
+
+	/*
+	 * Enable UART, GPIO9 as UART_SI, GPIO10 as UART_SO
+	 */
+	val = readl(regs + AR71XX_GPIO_REG_FUNC);
+	val |= AR933X_GPIO_FUNC_UART_EN | AR933X_GPIO_FUNC_RES_TRUE;
+	writel(val, regs + AR71XX_GPIO_REG_FUNC);
+}
+#endif
+
+int board_early_init_f(void)
+{
+#ifdef CONFIG_DEBUG_UART
+	debug_uart_init();
+#endif
+	ddr_init();
+	return 0;
+}