1 /*
2 * 16550 serial console support.
3 *
4 * Original copied from <file:arch/ppc/boot/common/ns16550.c>
5 * (which had no copyright)
6 * Modifications: 2006 (c) MontaVista Software, Inc.
7 *
8 * Modified by: Mark A. Greer <mgreer@mvista.com>
9 */
10 #include <stdarg.h>
11 #include <stddef.h>
12 #include "types.h"
13 #include "string.h"
14 #include "stdio.h"
15 #include "io.h"
16 #include "ops.h"
17 #include "of.h"
18
19 #define UART_DLL 0 /* Out: Divisor Latch Low */
20 #define UART_DLM 1 /* Out: Divisor Latch High */
21 #define UART_FCR 2 /* Out: FIFO Control Register */
22 #define UART_LCR 3 /* Out: Line Control Register */
23 #define UART_MCR 4 /* Out: Modem Control Register */
24 #define UART_LSR 5 /* In: Line Status Register */
25 #define UART_LSR_THRE 0x20 /* Transmit-hold-register empty */
26 #define UART_LSR_DR 0x01 /* Receiver data ready */
27 #define UART_MSR 6 /* In: Modem Status Register */
28 #define UART_SCR 7 /* I/O: Scratch Register */
29
30 static unsigned char *reg_base;
31 static u32 reg_shift;
32
ns16550_open(void)33 static int ns16550_open(void)
34 {
35 out_8(reg_base + (UART_FCR << reg_shift), 0x06);
36 return 0;
37 }
38
ns16550_putc(unsigned char c)39 static void ns16550_putc(unsigned char c)
40 {
41 while ((in_8(reg_base + (UART_LSR << reg_shift)) & UART_LSR_THRE) == 0);
42 out_8(reg_base, c);
43 }
44
ns16550_getc(void)45 static unsigned char ns16550_getc(void)
46 {
47 while ((in_8(reg_base + (UART_LSR << reg_shift)) & UART_LSR_DR) == 0);
48 return in_8(reg_base);
49 }
50
ns16550_tstc(void)51 static u8 ns16550_tstc(void)
52 {
53 return ((in_8(reg_base + (UART_LSR << reg_shift)) & UART_LSR_DR) != 0);
54 }
55
ns16550_console_init(void * devp,struct serial_console_data * scdp)56 int ns16550_console_init(void *devp, struct serial_console_data *scdp)
57 {
58 int n;
59 u32 reg_offset;
60
61 if (dt_get_virtual_reg(devp, (void **)®_base, 1) < 1) {
62 printf("virt reg parse fail...\r\n");
63 return -1;
64 }
65
66 n = getprop(devp, "reg-offset", ®_offset, sizeof(reg_offset));
67 if (n == sizeof(reg_offset))
68 reg_base += be32_to_cpu(reg_offset);
69
70 n = getprop(devp, "reg-shift", ®_shift, sizeof(reg_shift));
71 if (n != sizeof(reg_shift))
72 reg_shift = 0;
73 else
74 reg_shift = be32_to_cpu(reg_shift);
75
76 scdp->open = ns16550_open;
77 scdp->putc = ns16550_putc;
78 scdp->getc = ns16550_getc;
79 scdp->tstc = ns16550_tstc;
80 scdp->close = NULL;
81
82 return 0;
83 }
84