xref: /openbmc/u-boot/drivers/serial/ns16550.c (revision 9017d932)
1 /*
2  * COM1 NS16550 support
3  * originally from linux source (arch/ppc/boot/ns16550.c)
4  * modified to use CONFIG_SYS_ISA_MEM and new defines
5  */
6 
7 #include <config.h>
8 #include <ns16550.h>
9 
10 #define LCRVAL LCR_8N1					/* 8 data, 1 stop, no parity */
11 #define MCRVAL (MCR_DTR | MCR_RTS)			/* RTS/DTR */
12 #define FCRVAL (FCR_FIFO_EN | FCR_RXSR | FCR_TXSR)	/* Clear & enable FIFOs */
13 
14 void NS16550_init (NS16550_t com_port, int baud_divisor)
15 {
16 	com_port->ier = 0x00;
17 #ifdef CONFIG_OMAP
18 	com_port->mdr1 = 0x7;	/* mode select reset TL16C750*/
19 #endif
20 	com_port->lcr = LCR_BKSE | LCRVAL;
21 	com_port->dll = 0;
22 	com_port->dlm = 0;
23 	com_port->lcr = LCRVAL;
24 	com_port->mcr = MCRVAL;
25 	com_port->fcr = FCRVAL;
26 	com_port->lcr = LCR_BKSE | LCRVAL;
27 	com_port->dll = baud_divisor & 0xff;
28 	com_port->dlm = (baud_divisor >> 8) & 0xff;
29 	com_port->lcr = LCRVAL;
30 #if defined(CONFIG_OMAP)
31 #if defined(CONFIG_APTIX)
32 	com_port->mdr1 = 3;	/* /13 mode so Aptix 6MHz can hit 115200 */
33 #else
34 	com_port->mdr1 = 0;	/* /16 is proper to hit 115200 with 48MHz */
35 #endif
36 #endif /* CONFIG_OMAP */
37 }
38 
39 #ifndef CONFIG_NS16550_MIN_FUNCTIONS
40 void NS16550_reinit (NS16550_t com_port, int baud_divisor)
41 {
42 	com_port->ier = 0x00;
43 	com_port->lcr = LCR_BKSE | LCRVAL;
44 	com_port->dll = 0;
45 	com_port->dlm = 0;
46 	com_port->lcr = LCRVAL;
47 	com_port->mcr = MCRVAL;
48 	com_port->fcr = FCRVAL;
49 	com_port->lcr = LCR_BKSE;
50 	com_port->dll = baud_divisor & 0xff;
51 	com_port->dlm = (baud_divisor >> 8) & 0xff;
52 	com_port->lcr = LCRVAL;
53 }
54 #endif /* CONFIG_NS16550_MIN_FUNCTIONS */
55 
56 void NS16550_putc (NS16550_t com_port, char c)
57 {
58 	while ((com_port->lsr & LSR_THRE) == 0);
59 	com_port->thr = c;
60 }
61 
62 #ifndef CONFIG_NS16550_MIN_FUNCTIONS
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 /* CONFIG_NS16550_MIN_FUNCTIONS */
80