1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * AU1X00 UART support
4 *
5 * Hardcoded to UART 0 for now
6 * Speed and options also hardcoded to 115200 8N1
7 *
8 * Copyright (c) 2003 Thomas.Lange@corelatus.se
9 */
10
11 #include <config.h>
12 #include <common.h>
13 #include <mach/au1x00.h>
14 #include <serial.h>
15 #include <linux/compiler.h>
16
17 /******************************************************************************
18 *
19 * serial_init - initialize a channel
20 *
21 * This routine initializes the number of data bits, parity
22 * and set the selected baud rate. Interrupts are disabled.
23 * Set the modem control signals if the option is selected.
24 *
25 * RETURNS: N/A
26 */
27
au1x00_serial_init(void)28 static int au1x00_serial_init(void)
29 {
30 volatile u32 *uart_fifoctl = (volatile u32*)(UART0_ADDR+UART_FCR);
31 volatile u32 *uart_enable = (volatile u32*)(UART0_ADDR+UART_ENABLE);
32
33 /* Enable clocks first */
34 *uart_enable = UART_EN_CE;
35
36 /* Then release reset */
37 /* Must release reset before setting other regs */
38 *uart_enable = UART_EN_CE|UART_EN_E;
39
40 /* Activate fifos, reset tx and rx */
41 /* Set tx trigger level to 12 */
42 *uart_fifoctl = UART_FCR_ENABLE_FIFO|UART_FCR_CLEAR_RCVR|
43 UART_FCR_CLEAR_XMIT|UART_FCR_T_TRIGGER_12;
44
45 serial_setbrg();
46
47 return 0;
48 }
49
50
au1x00_serial_setbrg(void)51 static void au1x00_serial_setbrg(void)
52 {
53 volatile u32 *uart_clk = (volatile u32*)(UART0_ADDR+UART_CLK);
54 volatile u32 *uart_lcr = (volatile u32*)(UART0_ADDR+UART_LCR);
55 volatile u32 *sys_powerctrl = (u32 *)SYS_POWERCTRL;
56 int sd;
57 int divisorx2;
58
59 /* sd is system clock divisor */
60 /* see section 10.4.5 in au1550 datasheet */
61 sd = (*sys_powerctrl & 0x03) + 2;
62
63 /* calulate 2x baudrate and round */
64 divisorx2 = ((CONFIG_SYS_MIPS_TIMER_FREQ/(sd * 16 * CONFIG_BAUDRATE)));
65
66 if (divisorx2 & 0x01)
67 divisorx2 = divisorx2 + 1;
68
69 *uart_clk = divisorx2 / 2;
70
71 /* Set parity, stop bits and word length to 8N1 */
72 *uart_lcr = UART_LCR_WLEN8;
73 }
74
au1x00_serial_putc(const char c)75 static void au1x00_serial_putc(const char c)
76 {
77 volatile u32 *uart_lsr = (volatile u32*)(UART0_ADDR+UART_LSR);
78 volatile u32 *uart_tx = (volatile u32*)(UART0_ADDR+UART_TX);
79
80 if (c == '\n')
81 au1x00_serial_putc('\r');
82
83 /* Wait for fifo to shift out some bytes */
84 while((*uart_lsr&UART_LSR_THRE)==0);
85
86 *uart_tx = (u32)c;
87 }
88
au1x00_serial_getc(void)89 static int au1x00_serial_getc(void)
90 {
91 volatile u32 *uart_rx = (volatile u32*)(UART0_ADDR+UART_RX);
92 char c;
93
94 while (!serial_tstc());
95
96 c = (*uart_rx&0xFF);
97 return c;
98 }
99
au1x00_serial_tstc(void)100 static int au1x00_serial_tstc(void)
101 {
102 volatile u32 *uart_lsr = (volatile u32*)(UART0_ADDR+UART_LSR);
103
104 if(*uart_lsr&UART_LSR_DR){
105 /* Data in rfifo */
106 return(1);
107 }
108 return 0;
109 }
110
111 static struct serial_device au1x00_serial_drv = {
112 .name = "au1x00_serial",
113 .start = au1x00_serial_init,
114 .stop = NULL,
115 .setbrg = au1x00_serial_setbrg,
116 .putc = au1x00_serial_putc,
117 .puts = default_serial_puts,
118 .getc = au1x00_serial_getc,
119 .tstc = au1x00_serial_tstc,
120 };
121
au1x00_serial_initialize(void)122 void au1x00_serial_initialize(void)
123 {
124 serial_register(&au1x00_serial_drv);
125 }
126
default_serial_console(void)127 __weak struct serial_device *default_serial_console(void)
128 {
129 return &au1x00_serial_drv;
130 }
131