xref: /openbmc/u-boot/drivers/serial/ns16550.c (revision 415a613b)
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 = baud_divisor & 0xff;
25 	com_port->dlm = (baud_divisor >> 8) & 0xff;
26 	com_port->lcr = LCRVAL;
27 	com_port->mcr = MCRVAL;
28 	com_port->fcr = FCRVAL;
29 #if defined(CONFIG_OMAP)
30 #if defined(CONFIG_APTIX)
31 	com_port->mdr1 = 3;	/* /13 mode so Aptix 6MHz can hit 115200 */
32 #else
33 	com_port->mdr1 = 0;	/* /16 is proper to hit 115200 with 48MHz */
34 #endif
35 #endif
36 }
37 
38 void NS16550_reinit (NS16550_t com_port, int baud_divisor)
39 {
40 	com_port->ier = 0x00;
41 	com_port->lcr = LCR_BKSE;
42 	com_port->dll = baud_divisor & 0xff;
43 	com_port->dlm = (baud_divisor >> 8) & 0xff;
44 	com_port->lcr = LCRVAL;
45 	com_port->mcr = MCRVAL;
46 	com_port->fcr = FCRVAL;
47 }
48 
49 void NS16550_putc (NS16550_t com_port, char c)
50 {
51 	while ((com_port->lsr & LSR_THRE) == 0);
52 	com_port->thr = c;
53 }
54 
55 char NS16550_getc (NS16550_t com_port)
56 {
57 	while ((com_port->lsr & LSR_DR) == 0) {
58 #ifdef CONFIG_USB_TTY
59 		extern void usbtty_poll(void);
60 		usbtty_poll();
61 #endif
62 	}
63 	return (com_port->rbr);
64 }
65 
66 int NS16550_tstc (NS16550_t com_port)
67 {
68 	return ((com_port->lsr & LSR_DR) != 0);
69 }
70 
71 #endif
72