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/mips/mach-au1x00/au1x00_serial.c

@@ -0,0 +1,131 @@
+/*
+ * AU1X00 UART support
+ *
+ * Hardcoded to UART 0 for now
+ * Speed and options also hardcoded to 115200 8N1
+ *
+ *  Copyright (c) 2003	Thomas.Lange@corelatus.se
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <config.h>
+#include <common.h>
+#include <mach/au1x00.h>
+#include <serial.h>
+#include <linux/compiler.h>
+
+/******************************************************************************
+*
+* serial_init - initialize a channel
+*
+* This routine initializes the number of data bits, parity
+* and set the selected baud rate. Interrupts are disabled.
+* Set the modem control signals if the option is selected.
+*
+* RETURNS: N/A
+*/
+
+static int au1x00_serial_init(void)
+{
+	volatile u32 *uart_fifoctl = (volatile u32*)(UART0_ADDR+UART_FCR);
+	volatile u32 *uart_enable = (volatile u32*)(UART0_ADDR+UART_ENABLE);
+
+	/* Enable clocks first */
+	*uart_enable = UART_EN_CE;
+
+	/* Then release reset */
+	/* Must release reset before setting other regs */
+	*uart_enable = UART_EN_CE|UART_EN_E;
+
+	/* Activate fifos, reset tx and rx */
+	/* Set tx trigger level to 12 */
+	*uart_fifoctl = UART_FCR_ENABLE_FIFO|UART_FCR_CLEAR_RCVR|
+		UART_FCR_CLEAR_XMIT|UART_FCR_T_TRIGGER_12;
+
+	serial_setbrg();
+
+	return 0;
+}
+
+
+static void au1x00_serial_setbrg(void)
+{
+	volatile u32 *uart_clk = (volatile u32*)(UART0_ADDR+UART_CLK);
+	volatile u32 *uart_lcr = (volatile u32*)(UART0_ADDR+UART_LCR);
+	volatile u32 *sys_powerctrl = (u32 *)SYS_POWERCTRL;
+	int sd;
+	int divisorx2;
+
+	/* sd is system clock divisor			*/
+	/* see section 10.4.5 in au1550 datasheet	*/
+	sd = (*sys_powerctrl & 0x03) + 2;
+
+	/* calulate 2x baudrate and round */
+	divisorx2 = ((CONFIG_SYS_MIPS_TIMER_FREQ/(sd * 16 * CONFIG_BAUDRATE)));
+
+	if (divisorx2 & 0x01)
+		divisorx2 = divisorx2 + 1;
+
+	*uart_clk = divisorx2 / 2;
+
+	/* Set parity, stop bits and word length to 8N1 */
+	*uart_lcr = UART_LCR_WLEN8;
+}
+
+static void au1x00_serial_putc(const char c)
+{
+	volatile u32 *uart_lsr = (volatile u32*)(UART0_ADDR+UART_LSR);
+	volatile u32 *uart_tx = (volatile u32*)(UART0_ADDR+UART_TX);
+
+	if (c == '\n')
+		au1x00_serial_putc('\r');
+
+	/* Wait for fifo to shift out some bytes */
+	while((*uart_lsr&UART_LSR_THRE)==0);
+
+	*uart_tx = (u32)c;
+}
+
+static int au1x00_serial_getc(void)
+{
+	volatile u32 *uart_rx = (volatile u32*)(UART0_ADDR+UART_RX);
+	char c;
+
+	while (!serial_tstc());
+
+	c = (*uart_rx&0xFF);
+	return c;
+}
+
+static int au1x00_serial_tstc(void)
+{
+	volatile u32 *uart_lsr = (volatile u32*)(UART0_ADDR+UART_LSR);
+
+	if(*uart_lsr&UART_LSR_DR){
+		/* Data in rfifo */
+		return(1);
+	}
+	return 0;
+}
+
+static struct serial_device au1x00_serial_drv = {
+	.name	= "au1x00_serial",
+	.start	= au1x00_serial_init,
+	.stop	= NULL,
+	.setbrg	= au1x00_serial_setbrg,
+	.putc	= au1x00_serial_putc,
+	.puts	= default_serial_puts,
+	.getc	= au1x00_serial_getc,
+	.tstc	= au1x00_serial_tstc,
+};
+
+void au1x00_serial_initialize(void)
+{
+	serial_register(&au1x00_serial_drv);
+}
+
+__weak struct serial_device *default_serial_console(void)
+{
+	return &au1x00_serial_drv;
+}