xref: /openbmc/u-boot/drivers/serial/ns16550.c (revision a4145534)
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 #include <watchdog.h>
10 
11 #define UART_LCRVAL UART_LCR_8N1		/* 8 data, 1 stop, no parity */
12 #define UART_MCRVAL (UART_MCR_DTR | \
13 		     UART_MCR_RTS)		/* RTS/DTR */
14 #define UART_FCRVAL (UART_FCR_FIFO_EN |	\
15 		     UART_FCR_RXSR |	\
16 		     UART_FCR_TXSR)		/* Clear & enable FIFOs */
17 
18 void NS16550_init (NS16550_t com_port, int baud_divisor)
19 {
20 	com_port->ier = 0x00;
21 #if defined(CONFIG_OMAP) && !defined(CONFIG_OMAP3_ZOOM2)
22 	com_port->mdr1 = 0x7;	/* mode select reset TL16C750*/
23 #endif
24 	com_port->lcr = UART_LCR_BKSE | UART_LCRVAL;
25 	com_port->dll = 0;
26 	com_port->dlm = 0;
27 	com_port->lcr = UART_LCRVAL;
28 	com_port->mcr = UART_MCRVAL;
29 	com_port->fcr = UART_FCRVAL;
30 	com_port->lcr = UART_LCR_BKSE | UART_LCRVAL;
31 	com_port->dll = baud_divisor & 0xff;
32 	com_port->dlm = (baud_divisor >> 8) & 0xff;
33 	com_port->lcr = UART_LCRVAL;
34 #if defined(CONFIG_OMAP) && !defined(CONFIG_OMAP3_ZOOM2)
35 #if defined(CONFIG_APTIX)
36 	com_port->mdr1 = 3;	/* /13 mode so Aptix 6MHz can hit 115200 */
37 #else
38 	com_port->mdr1 = 0;	/* /16 is proper to hit 115200 with 48MHz */
39 #endif
40 #endif /* CONFIG_OMAP */
41 }
42 
43 #ifndef CONFIG_NS16550_MIN_FUNCTIONS
44 void NS16550_reinit (NS16550_t com_port, int baud_divisor)
45 {
46 	com_port->ier = 0x00;
47 	com_port->lcr = UART_LCR_BKSE | UART_LCRVAL;
48 	com_port->dll = 0;
49 	com_port->dlm = 0;
50 	com_port->lcr = UART_LCRVAL;
51 	com_port->mcr = UART_MCRVAL;
52 	com_port->fcr = UART_FCRVAL;
53 	com_port->lcr = UART_LCR_BKSE;
54 	com_port->dll = baud_divisor & 0xff;
55 	com_port->dlm = (baud_divisor >> 8) & 0xff;
56 	com_port->lcr = UART_LCRVAL;
57 }
58 #endif /* CONFIG_NS16550_MIN_FUNCTIONS */
59 
60 void NS16550_putc (NS16550_t com_port, char c)
61 {
62 	while ((com_port->lsr & UART_LSR_THRE) == 0);
63 	com_port->thr = c;
64 }
65 
66 #ifndef CONFIG_NS16550_MIN_FUNCTIONS
67 char NS16550_getc (NS16550_t com_port)
68 {
69 	while ((com_port->lsr & UART_LSR_DR) == 0) {
70 #ifdef CONFIG_USB_TTY
71 		extern void usbtty_poll(void);
72 		usbtty_poll();
73 #endif
74 		WATCHDOG_RESET();
75 	}
76 	return (com_port->rbr);
77 }
78 
79 int NS16550_tstc (NS16550_t com_port)
80 {
81 	return ((com_port->lsr & UART_LSR_DR) != 0);
82 }
83 
84 #endif /* CONFIG_NS16550_MIN_FUNCTIONS */
85