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
18 #define UART_DLL 0 /* Out: Divisor Latch Low */
19 #define UART_DLM 1 /* Out: Divisor Latch High */
20 #define UART_FCR 2 /* Out: FIFO Control Register */
21 #define UART_LCR 3 /* Out: Line Control Register */
22 #define UART_MCR 4 /* Out: Modem Control Register */
23 #define UART_LSR 5 /* In: Line Status Register */
24 #define UART_LSR_THRE 0x20 /* Transmit-hold-register empty */
25 #define UART_LSR_DR 0x01 /* Receiver data ready */
26 #define UART_MSR 6 /* In: Modem Status Register */
27 #define UART_SCR 7 /* I/O: Scratch Register */
28
29 static unsigned char *reg_base;
30 static u32 reg_shift;
31
ns16550_open(void)32 static int ns16550_open(void)
33 {
34 out_8(reg_base + (UART_FCR << reg_shift), 0x06);
35 return 0;
36 }
37
ns16550_putc(unsigned char c)38 static void ns16550_putc(unsigned char c)
39 {
40 while ((in_8(reg_base + (UART_LSR << reg_shift)) & UART_LSR_THRE) == 0);
41 out_8(reg_base, c);
42 }
43
ns16550_getc(void)44 static unsigned char ns16550_getc(void)
45 {
46 while ((in_8(reg_base + (UART_LSR << reg_shift)) & UART_LSR_DR) == 0);
47 return in_8(reg_base);
48 }
49
ns16550_tstc(void)50 static u8 ns16550_tstc(void)
51 {
52 return ((in_8(reg_base + (UART_LSR << reg_shift)) & UART_LSR_DR) != 0);
53 }
54
ns16550_console_init(void * devp,struct serial_console_data * scdp)55 int ns16550_console_init(void *devp, struct serial_console_data *scdp)
56 {
57 int n;
58 u32 reg_offset;
59
60 if (dt_get_virtual_reg(devp, (void **)®_base, 1) < 1)
61 return -1;
62
63 n = getprop(devp, "reg-offset", ®_offset, sizeof(reg_offset));
64 if (n == sizeof(reg_offset))
65 reg_base += reg_offset;
66
67 n = getprop(devp, "reg-shift", ®_shift, sizeof(reg_shift));
68 if (n != sizeof(reg_shift))
69 reg_shift = 0;
70
71 scdp->open = ns16550_open;
72 scdp->putc = ns16550_putc;
73 scdp->getc = ns16550_getc;
74 scdp->tstc = ns16550_tstc;
75 scdp->close = NULL;
76
77 return 0;
78 }
79