avionic design with actual uboot and tooling

submodule of avionic design uboot bootloader and with included tools to
get you started , read readme.md and readme-tk1-loader.md

u-boot/arch/arm/mach-tegra/tegra124/funcmux.c

@@ -0,0 +1,71 @@
+/*
+ * (C) Copyright 2013
+ * NVIDIA Corporation <www.nvidia.com>
+ *
+ * SPDX-License-Identifier:     GPL-2.0+
+ */
+
+/* Tegra124 high-level function multiplexing */
+
+#include <common.h>
+#include <asm/arch/clock.h>
+#include <asm/arch/funcmux.h>
+#include <asm/arch/pinmux.h>
+
+int funcmux_select(enum periph_id id, int config)
+{
+	int bad_config = config != FUNCMUX_DEFAULT;
+
+	switch (id) {
+	case PERIPH_ID_UART4:
+		switch (config) {
+		case FUNCMUX_UART4_GPIO: /* TXD,RXD,CTS,RTS */
+			pinmux_set_func(PMUX_PINGRP_PJ7, PMUX_FUNC_UARTD);
+			pinmux_set_func(PMUX_PINGRP_PB0, PMUX_FUNC_UARTD);
+			pinmux_set_func(PMUX_PINGRP_PB1, PMUX_FUNC_UARTD);
+			pinmux_set_func(PMUX_PINGRP_PK7, PMUX_FUNC_UARTD);
+
+			pinmux_set_io(PMUX_PINGRP_PJ7, PMUX_PIN_OUTPUT);
+			pinmux_set_io(PMUX_PINGRP_PB0, PMUX_PIN_INPUT);
+			pinmux_set_io(PMUX_PINGRP_PB1, PMUX_PIN_INPUT);
+			pinmux_set_io(PMUX_PINGRP_PK7, PMUX_PIN_OUTPUT);
+
+			pinmux_tristate_disable(PMUX_PINGRP_PJ7);
+			pinmux_tristate_disable(PMUX_PINGRP_PB0);
+			pinmux_tristate_disable(PMUX_PINGRP_PB1);
+			pinmux_tristate_disable(PMUX_PINGRP_PK7);
+			break;
+		}
+		break;
+
+	case PERIPH_ID_UART1:
+		switch (config) {
+		case FUNCMUX_UART1_KBC:
+			pinmux_set_func(PMUX_PINGRP_KB_ROW9_PS1,
+					PMUX_FUNC_UARTA);
+			pinmux_set_func(PMUX_PINGRP_KB_ROW10_PS2,
+					PMUX_FUNC_UARTA);
+
+			pinmux_set_io(PMUX_PINGRP_KB_ROW9_PS1, PMUX_PIN_OUTPUT);
+			pinmux_set_io(PMUX_PINGRP_KB_ROW10_PS2, PMUX_PIN_INPUT);
+
+			pinmux_tristate_disable(PMUX_PINGRP_KB_ROW9_PS1);
+			pinmux_tristate_disable(PMUX_PINGRP_KB_ROW10_PS2);
+			break;
+		}
+		break;
+
+	/* Add other periph IDs here as needed */
+
+	default:
+		debug("%s: invalid periph_id %d", __func__, id);
+		return -1;
+	}
+
+	if (bad_config) {
+		debug("%s: invalid config %d for periph_id %d", __func__,
+		      config, id);
+		return -1;
+	}
+	return 0;
+}