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-davinci/pinmux.c

@@ -0,0 +1,90 @@
+/*
+ * DaVinci pinmux functions.
+ *
+ * Copyright (C) 2009 Nick Thompson, GE Fanuc Ltd, <nick.thompson@gefanuc.com>
+ * Copyright (C) 2007 Sergey Kubushyn <ksi@koi8.net>
+ * Copyright (C) 2008 Lyrtech <www.lyrtech.com>
+ * Copyright (C) 2004 Texas Instruments.
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <asm/arch/hardware.h>
+#include <asm/io.h>
+#include <asm/arch/davinci_misc.h>
+
+/*
+ * Change the setting of a pin multiplexer field.
+ *
+ * Takes an array of pinmux settings similar to:
+ *
+ * struct pinmux_config uart_pins[] = {
+ *	{ &davinci_syscfg_regs->pinmux[8], 2, 7 },
+ *	{ &davinci_syscfg_regs->pinmux[9], 2, 0 }
+ * };
+ *
+ * Stepping through the array, each pinmux[n] register has the given value
+ * set in the pin mux field specified.
+ *
+ * The number of pins in the array must be passed (ARRAY_SIZE can provide
+ * this value conveniently).
+ *
+ * Returns 0 if all field numbers and values are in the correct range,
+ * else returns -1.
+ */
+int davinci_configure_pin_mux(const struct pinmux_config *pins,
+			      const int n_pins)
+{
+	int i;
+
+	/* check for invalid pinmux values */
+	for (i = 0; i < n_pins; i++) {
+		if (pins[i].field >= PIN_MUX_NUM_FIELDS ||
+		    (pins[i].value & ~PIN_MUX_FIELD_MASK) != 0)
+			return -1;
+	}
+
+	/* configure the pinmuxes */
+	for (i = 0; i < n_pins; i++) {
+		const int offset = pins[i].field * PIN_MUX_FIELD_SIZE;
+		const unsigned int value = pins[i].value << offset;
+		const unsigned int mask = PIN_MUX_FIELD_MASK << offset;
+		const dv_reg *mux = pins[i].mux;
+
+		writel(value | (readl(mux) & (~mask)), mux);
+	}
+
+	return 0;
+}
+
+/*
+ * Configure multiple pinmux resources.
+ *
+ * Takes an pinmux_resource array of pinmux_config and pin counts:
+ *
+ * const struct pinmux_resource pinmuxes[] = {
+ *	PINMUX_ITEM(uart_pins),
+ *	PINMUX_ITEM(i2c_pins),
+ * };
+ *
+ * The number of items in the array must be passed (ARRAY_SIZE can provide
+ * this value conveniently).
+ *
+ * Each item entry is configured in the defined order. If configuration
+ * of any item fails, -1 is returned and none of the following items are
+ * configured. On success, 0 is returned.
+ */
+int davinci_configure_pin_mux_items(const struct pinmux_resource *item,
+				    const int n_items)
+{
+	int i;
+
+	for (i = 0; i < n_items; i++) {
+		if (davinci_configure_pin_mux(item[i].pins,
+					      item[i].n_pins) != 0)
+			return -1;
+	}
+
+	return 0;
+}