File: /usr/src/linux/arch/ppc/boot/common/ns16550.c

1     /*
2      * BK Id: SCCS/s.ns16550.c 1.9 07/30/01 17:19:40 trini
3      */
4     /*
5      * COM1 NS16550 support
6      */
7     
8     #include <linux/config.h>
9     #include <linux/serialP.h>
10     #include <linux/serial_reg.h>
11     #include <asm/serial.h>
12     
13     extern void outb(int port, unsigned char val);
14     extern unsigned char inb(int port);
15     extern unsigned long ISA_io;
16     
17     static struct serial_state rs_table[RS_TABLE_SIZE] = {
18     	SERIAL_PORT_DFNS	/* Defined in <asm/serial.h> */
19     };
20     
21     static int shift;
22     
23     unsigned long serial_init(int chan) {
24     	unsigned long com_port;
25     
26     	/* We need to find out which type io we're expecting.  If it's
27     	 * 'SERIAL_IO_PORT', we get an offset from the isa_io_base.
28     	 * If it's 'SERIAL_IO_MEM', we can the exact location.  -- Tom */
29     	switch (rs_table[chan].io_type) {
30     		case SERIAL_IO_PORT:
31     			com_port = rs_table[chan].port;
32     			break;
33     		case SERIAL_IO_MEM:
34     			com_port = (unsigned long)rs_table[chan].iomem_base;
35     			break;
36     		default:
37     			/* We can't deal with it. */
38     			return -1;
39     	}
40     
41     	/* How far apart the registers are. */
42     	shift = rs_table[chan].iomem_reg_shift;
43     
44     	/* See if port is present */
45     	outb(com_port + (UART_LCR << shift), 0x00);
46     	outb(com_port + (UART_IER << shift), 0x00);
47     	/* Access baud rate */
48     	outb(com_port + (UART_LCR << shift), 0x80);
49     #ifdef CONFIG_SERIAL_CONSOLE_NONSTD
50     	/* Input clock. */
51     	outb(com_port + (UART_DLL << shift), 
52     			(BASE_BAUD / CONFIG_SERIAL_CONSOLE_BAUD));
53     	outb(com_port + (UART_DLM << shift), 
54     		(BASE_BAUD / CONFIG_SERIAL_CONSOLE_BAUD) >> 8);
55     #endif
56     	 /* 8 data, 1 stop, no parity */
57     	outb(com_port + (UART_LCR << shift), 0x03);
58     	/* RTS/DTR */
59     	outb(com_port + (UART_MCR << shift), 0x03);
60     	/* Clear & enable FIFOs */
61     	outb(com_port + (UART_FCR << shift), 0x07);
62     
63     	return (com_port);
64     }
65     
66     void
67     serial_putc(unsigned long com_port, unsigned char c)
68     {
69     	while ((inb(com_port + (UART_LSR << shift)) & UART_LSR_THRE) == 0)
70     		;
71     	outb(com_port, c);
72     }
73     
74     unsigned char
75     serial_getc(unsigned long com_port)
76     {
77     	while ((inb(com_port + (UART_LSR << shift)) & UART_LSR_DR) == 0)
78     		;
79     	return inb(com_port);
80     }
81     
82     int
83     serial_tstc(unsigned long com_port)
84     {
85     	return ((inb(com_port + (UART_LSR << shift)) & UART_LSR_DR) != 0);
86     }
87