4 * Hardcoded to UART 0 for now
5 * Speed and options also hardcoded to 115200 8N1
7 * Copyright (c) 2003 Thomas.Lange@corelatus.se
9 * SPDX-License-Identifier: GPL-2.0+
14 #include <asm/au1x00.h>
16 #include <linux/compiler.h>
18 /******************************************************************************
20 * serial_init - initialize a channel
22 * This routine initializes the number of data bits, parity
23 * and set the selected baud rate. Interrupts are disabled.
24 * Set the modem control signals if the option is selected.
29 static int au1x00_serial_init(void)
31 volatile u32 *uart_fifoctl = (volatile u32*)(UART0_ADDR+UART_FCR);
32 volatile u32 *uart_enable = (volatile u32*)(UART0_ADDR+UART_ENABLE);
34 /* Enable clocks first */
35 *uart_enable = UART_EN_CE;
37 /* Then release reset */
38 /* Must release reset before setting other regs */
39 *uart_enable = UART_EN_CE|UART_EN_E;
41 /* Activate fifos, reset tx and rx */
42 /* Set tx trigger level to 12 */
43 *uart_fifoctl = UART_FCR_ENABLE_FIFO|UART_FCR_CLEAR_RCVR|
44 UART_FCR_CLEAR_XMIT|UART_FCR_T_TRIGGER_12;
52 static void au1x00_serial_setbrg(void)
54 volatile u32 *uart_clk = (volatile u32*)(UART0_ADDR+UART_CLK);
55 volatile u32 *uart_lcr = (volatile u32*)(UART0_ADDR+UART_LCR);
56 volatile u32 *sys_powerctrl = (u32 *)SYS_POWERCTRL;
60 /* sd is system clock divisor */
61 /* see section 10.4.5 in au1550 datasheet */
62 sd = (*sys_powerctrl & 0x03) + 2;
64 /* calulate 2x baudrate and round */
65 divisorx2 = ((CONFIG_SYS_MIPS_TIMER_FREQ/(sd * 16 * CONFIG_BAUDRATE)));
68 divisorx2 = divisorx2 + 1;
70 *uart_clk = divisorx2 / 2;
72 /* Set parity, stop bits and word length to 8N1 */
73 *uart_lcr = UART_LCR_WLEN8;
76 static void au1x00_serial_putc(const char c)
78 volatile u32 *uart_lsr = (volatile u32*)(UART0_ADDR+UART_LSR);
79 volatile u32 *uart_tx = (volatile u32*)(UART0_ADDR+UART_TX);
82 au1x00_serial_putc('\r');
84 /* Wait for fifo to shift out some bytes */
85 while((*uart_lsr&UART_LSR_THRE)==0);
90 static int au1x00_serial_getc(void)
92 volatile u32 *uart_rx = (volatile u32*)(UART0_ADDR+UART_RX);
95 while (!serial_tstc());
101 static int au1x00_serial_tstc(void)
103 volatile u32 *uart_lsr = (volatile u32*)(UART0_ADDR+UART_LSR);
105 if(*uart_lsr&UART_LSR_DR){
112 static struct serial_device au1x00_serial_drv = {
113 .name = "au1x00_serial",
114 .start = au1x00_serial_init,
116 .setbrg = au1x00_serial_setbrg,
117 .putc = au1x00_serial_putc,
118 .puts = default_serial_puts,
119 .getc = au1x00_serial_getc,
120 .tstc = au1x00_serial_tstc,
123 void au1x00_serial_initialize(void)
125 serial_register(&au1x00_serial_drv);
128 __weak struct serial_device *default_serial_console(void)
130 return &au1x00_serial_drv;