xref: /openbmc/u-boot/drivers/serial/ns16550.c (revision 3d36be03)
1 /*
2  * COM1 NS16550 support
3  * originally from linux source (arch/ppc/boot/ns16550.c)
4  * modified to use CFG_ISA_MEM and new defines
5  */
6 
7 #include <config.h>
8 
9 #ifdef CFG_NS16550
10 
11 #include <ns16550.h>
12 
13 #define LCRVAL LCR_8N1					/* 8 data, 1 stop, no parity */
14 #define MCRVAL (MCR_DTR | MCR_RTS)			/* RTS/DTR */
15 #define FCRVAL (FCR_FIFO_EN | FCR_RXSR | FCR_TXSR)	/* Clear & enable FIFOs */
16 
17 void NS16550_init (NS16550_t com_port, int baud_divisor)
18 {
19 	com_port->ier = 0x00;
20 #ifdef CONFIG_OMAP
21 	com_port->mdr1 = 0x7;	/* mode select reset TL16C750*/
22 #endif
23 	com_port->lcr = LCR_BKSE | LCRVAL;
24 	com_port->dll = 0;
25 	com_port->dlm = 0;
26 	com_port->lcr = LCRVAL;
27 	com_port->mcr = MCRVAL;
28 	com_port->fcr = FCRVAL;
29 	com_port->lcr = LCR_BKSE | LCRVAL;
30 	com_port->dll = baud_divisor & 0xff;
31 	com_port->dlm = (baud_divisor >> 8) & 0xff;
32 	com_port->lcr = LCRVAL;
33 #if defined(CONFIG_OMAP)
34 #if defined(CONFIG_APTIX)
35 	com_port->mdr1 = 3;	/* /13 mode so Aptix 6MHz can hit 115200 */
36 #else
37 	com_port->mdr1 = 0;	/* /16 is proper to hit 115200 with 48MHz */
38 #endif
39 #endif
40 }
41 
42 void NS16550_reinit (NS16550_t com_port, int baud_divisor)
43 {
44 	com_port->ier = 0x00;
45 	com_port->lcr = LCR_BKSE | LCRVAL;
46 	com_port->dll = 0;
47 	com_port->dlm = 0;
48 	com_port->lcr = LCRVAL;
49 	com_port->mcr = MCRVAL;
50 	com_port->fcr = FCRVAL;
51 	com_port->lcr = LCR_BKSE;
52 	com_port->dll = baud_divisor & 0xff;
53 	com_port->dlm = (baud_divisor >> 8) & 0xff;
54 	com_port->lcr = LCRVAL;
55 }
56 
57 void NS16550_putc (NS16550_t com_port, char c)
58 {
59 	while ((com_port->lsr & LSR_THRE) == 0);
60 	com_port->thr = c;
61 }
62 
63 char NS16550_getc (NS16550_t com_port)
64 {
65 	while ((com_port->lsr & LSR_DR) == 0) {
66 #ifdef CONFIG_USB_TTY
67 		extern void usbtty_poll(void);
68 		usbtty_poll();
69 #endif
70 	}
71 	return (com_port->rbr);
72 }
73 
74 int NS16550_tstc (NS16550_t com_port)
75 {
76 	return ((com_port->lsr & LSR_DR) != 0);
77 }
78 
79 #endif
80