xref: /openbmc/u-boot/drivers/serial/ns16550.c (revision 25793f76)
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 UART_LCRVAL UART_LCR_8N1		/* 8 data, 1 stop, no parity */
11 #define UART_MCRVAL (UART_MCR_DTR | \
12 		     UART_MCR_RTS)		/* RTS/DTR */
13 #define UART_FCRVAL (UART_FCR_FIFO_EN |	\
14 		     UART_FCR_RXSR |	\
15 		     UART_FCR_TXSR)		/* Clear & enable FIFOs */
16 
17 void NS16550_init (NS16550_t com_port, int baud_divisor)
18 {
19 	com_port->ier = 0x00;
20 #if defined(CONFIG_OMAP) && !defined(CONFIG_OMAP3_ZOOM2)
21 	com_port->mdr1 = 0x7;	/* mode select reset TL16C750*/
22 #endif
23 	com_port->lcr = UART_LCR_BKSE | UART_LCRVAL;
24 	com_port->dll = 0;
25 	com_port->dlm = 0;
26 	com_port->lcr = UART_LCRVAL;
27 	com_port->mcr = UART_MCRVAL;
28 	com_port->fcr = UART_FCRVAL;
29 	com_port->lcr = UART_LCR_BKSE | UART_LCRVAL;
30 	com_port->dll = baud_divisor & 0xff;
31 	com_port->dlm = (baud_divisor >> 8) & 0xff;
32 	com_port->lcr = UART_LCRVAL;
33 #if defined(CONFIG_OMAP) && !defined(CONFIG_OMAP3_ZOOM2)
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 /* CONFIG_OMAP */
40 }
41 
42 #ifndef CONFIG_NS16550_MIN_FUNCTIONS
43 void NS16550_reinit (NS16550_t com_port, int baud_divisor)
44 {
45 	com_port->ier = 0x00;
46 	com_port->lcr = UART_LCR_BKSE | UART_LCRVAL;
47 	com_port->dll = 0;
48 	com_port->dlm = 0;
49 	com_port->lcr = UART_LCRVAL;
50 	com_port->mcr = UART_MCRVAL;
51 	com_port->fcr = UART_FCRVAL;
52 	com_port->lcr = UART_LCR_BKSE;
53 	com_port->dll = baud_divisor & 0xff;
54 	com_port->dlm = (baud_divisor >> 8) & 0xff;
55 	com_port->lcr = UART_LCRVAL;
56 }
57 #endif /* CONFIG_NS16550_MIN_FUNCTIONS */
58 
59 void NS16550_putc (NS16550_t com_port, char c)
60 {
61 	while ((com_port->lsr & UART_LSR_THRE) == 0);
62 	com_port->thr = c;
63 }
64 
65 #ifndef CONFIG_NS16550_MIN_FUNCTIONS
66 char NS16550_getc (NS16550_t com_port)
67 {
68 	while ((com_port->lsr & UART_LSR_DR) == 0) {
69 #ifdef CONFIG_USB_TTY
70 		extern void usbtty_poll(void);
71 		usbtty_poll();
72 #endif
73 	}
74 	return (com_port->rbr);
75 }
76 
77 int NS16550_tstc (NS16550_t com_port)
78 {
79 	return ((com_port->lsr & UART_LSR_DR) != 0);
80 }
81 
82 #endif /* CONFIG_NS16550_MIN_FUNCTIONS */
83