xref: /openbmc/u-boot/drivers/serial/ns16550.c (revision f51cdaf1)
1 /*
2  * COM1 NS16550 support
3  * originally from linux source (arch/powerpc/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 #include <linux/types.h>
11 #include <asm/io.h>
12 
13 #define UART_LCRVAL UART_LCR_8N1		/* 8 data, 1 stop, no parity */
14 #define UART_MCRVAL (UART_MCR_DTR | \
15 		     UART_MCR_RTS)		/* RTS/DTR */
16 #define UART_FCRVAL (UART_FCR_FIFO_EN |	\
17 		     UART_FCR_RXSR |	\
18 		     UART_FCR_TXSR)		/* Clear & enable FIFOs */
19 #ifdef CONFIG_SYS_NS16550_PORT_MAPPED
20 #define serial_out(x,y)	outb(x,(ulong)y)
21 #define serial_in(y)	inb((ulong)y)
22 #else
23 #define serial_out(x,y) writeb(x,y)
24 #define serial_in(y) 	readb(y)
25 #endif
26 
27 void NS16550_init (NS16550_t com_port, int baud_divisor)
28 {
29 	serial_out(0x00, &com_port->ier);
30 #if defined(CONFIG_OMAP) && !defined(CONFIG_OMAP3_ZOOM2)
31 	serial_out(0x7, &com_port->mdr1);	/* mode select reset TL16C750*/
32 #endif
33 	serial_out(UART_LCR_BKSE | UART_LCRVAL, (ulong)&com_port->lcr);
34 	serial_out(0, &com_port->dll);
35 	serial_out(0, &com_port->dlm);
36 	serial_out(UART_LCRVAL, &com_port->lcr);
37 	serial_out(UART_MCRVAL, &com_port->mcr);
38 	serial_out(UART_FCRVAL, &com_port->fcr);
39 	serial_out(UART_LCR_BKSE | UART_LCRVAL, &com_port->lcr);
40 	serial_out(baud_divisor & 0xff, &com_port->dll);
41 	serial_out((baud_divisor >> 8) & 0xff, &com_port->dlm);
42 	serial_out(UART_LCRVAL, &com_port->lcr);
43 #if defined(CONFIG_OMAP) && !defined(CONFIG_OMAP3_ZOOM2)
44 #if defined(CONFIG_APTIX)
45 	serial_out(3, &com_port->mdr1);	/* /13 mode so Aptix 6MHz can hit 115200 */
46 #else
47 	serial_out(0, &com_port->mdr1);	/* /16 is proper to hit 115200 with 48MHz */
48 #endif
49 #endif /* CONFIG_OMAP */
50 }
51 
52 #ifndef CONFIG_NS16550_MIN_FUNCTIONS
53 void NS16550_reinit (NS16550_t com_port, int baud_divisor)
54 {
55 	serial_out(0x00, &com_port->ier);
56 	serial_out(UART_LCR_BKSE | UART_LCRVAL, &com_port->lcr);
57 	serial_out(0, &com_port->dll);
58 	serial_out(0, &com_port->dlm);
59 	serial_out(UART_LCRVAL, &com_port->lcr);
60 	serial_out(UART_MCRVAL, &com_port->mcr);
61 	serial_out(UART_FCRVAL, &com_port->fcr);
62 	serial_out(UART_LCR_BKSE, &com_port->lcr);
63 	serial_out(baud_divisor & 0xff, &com_port->dll);
64 	serial_out((baud_divisor >> 8) & 0xff, &com_port->dlm);
65 	serial_out(UART_LCRVAL, &com_port->lcr);
66 }
67 #endif /* CONFIG_NS16550_MIN_FUNCTIONS */
68 
69 void NS16550_putc (NS16550_t com_port, char c)
70 {
71 	while ((serial_in(&com_port->lsr) & UART_LSR_THRE) == 0);
72 	serial_out(c, &com_port->thr);
73 }
74 
75 #ifndef CONFIG_NS16550_MIN_FUNCTIONS
76 char NS16550_getc (NS16550_t com_port)
77 {
78 	while ((serial_in(&com_port->lsr) & UART_LSR_DR) == 0) {
79 #ifdef CONFIG_USB_TTY
80 		extern void usbtty_poll(void);
81 		usbtty_poll();
82 #endif
83 		WATCHDOG_RESET();
84 	}
85 	return serial_in(&com_port->rbr);
86 }
87 
88 int NS16550_tstc (NS16550_t com_port)
89 {
90 	return ((serial_in(&com_port->lsr) & UART_LSR_DR) != 0);
91 }
92 
93 #endif /* CONFIG_NS16550_MIN_FUNCTIONS */
94