xref: /openbmc/u-boot/drivers/serial/ns16550.c (revision 419adbfb)
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 #ifndef CONFIG_SYS_NS16550_IER
28 #define CONFIG_SYS_NS16550_IER  0x00
29 #endif /* CONFIG_SYS_NS16550_IER */
30 
31 void NS16550_init (NS16550_t com_port, int baud_divisor)
32 {
33 	serial_out(CONFIG_SYS_NS16550_IER, &com_port->ier);
34 #if defined(CONFIG_OMAP) && !defined(CONFIG_OMAP3_ZOOM2)
35 	serial_out(0x7, &com_port->mdr1);	/* mode select reset TL16C750*/
36 #endif
37 	serial_out(UART_LCR_BKSE | UART_LCRVAL, (ulong)&com_port->lcr);
38 	serial_out(0, &com_port->dll);
39 	serial_out(0, &com_port->dlm);
40 	serial_out(UART_LCRVAL, &com_port->lcr);
41 	serial_out(UART_MCRVAL, &com_port->mcr);
42 	serial_out(UART_FCRVAL, &com_port->fcr);
43 	serial_out(UART_LCR_BKSE | UART_LCRVAL, &com_port->lcr);
44 	serial_out(baud_divisor & 0xff, &com_port->dll);
45 	serial_out((baud_divisor >> 8) & 0xff, &com_port->dlm);
46 	serial_out(UART_LCRVAL, &com_port->lcr);
47 #if defined(CONFIG_OMAP) && !defined(CONFIG_OMAP3_ZOOM2)
48 #if defined(CONFIG_APTIX)
49 	serial_out(3, &com_port->mdr1);	/* /13 mode so Aptix 6MHz can hit 115200 */
50 #else
51 	serial_out(0, &com_port->mdr1);	/* /16 is proper to hit 115200 with 48MHz */
52 #endif
53 #endif /* CONFIG_OMAP */
54 }
55 
56 #ifndef CONFIG_NS16550_MIN_FUNCTIONS
57 void NS16550_reinit (NS16550_t com_port, int baud_divisor)
58 {
59 	serial_out(CONFIG_SYS_NS16550_IER, &com_port->ier);
60 	serial_out(UART_LCR_BKSE | UART_LCRVAL, &com_port->lcr);
61 	serial_out(0, &com_port->dll);
62 	serial_out(0, &com_port->dlm);
63 	serial_out(UART_LCRVAL, &com_port->lcr);
64 	serial_out(UART_MCRVAL, &com_port->mcr);
65 	serial_out(UART_FCRVAL, &com_port->fcr);
66 	serial_out(UART_LCR_BKSE, &com_port->lcr);
67 	serial_out(baud_divisor & 0xff, &com_port->dll);
68 	serial_out((baud_divisor >> 8) & 0xff, &com_port->dlm);
69 	serial_out(UART_LCRVAL, &com_port->lcr);
70 }
71 #endif /* CONFIG_NS16550_MIN_FUNCTIONS */
72 
73 void NS16550_putc (NS16550_t com_port, char c)
74 {
75 	while ((serial_in(&com_port->lsr) & UART_LSR_THRE) == 0);
76 	serial_out(c, &com_port->thr);
77 
78 	/*
79 	 * Call watchdog_reset() upon newline. This is done here in putc
80 	 * since the environment code uses a single puts() to print the complete
81 	 * environment upon "printenv". So we can't put this watchdog call
82 	 * in puts().
83 	 */
84 	if (c == '\n')
85 		WATCHDOG_RESET();
86 }
87 
88 #ifndef CONFIG_NS16550_MIN_FUNCTIONS
89 char NS16550_getc (NS16550_t com_port)
90 {
91 	while ((serial_in(&com_port->lsr) & UART_LSR_DR) == 0) {
92 #ifdef CONFIG_USB_TTY
93 		extern void usbtty_poll(void);
94 		usbtty_poll();
95 #endif
96 		WATCHDOG_RESET();
97 	}
98 	return serial_in(&com_port->rbr);
99 }
100 
101 int NS16550_tstc (NS16550_t com_port)
102 {
103 	return ((serial_in(&com_port->lsr) & UART_LSR_DR) != 0);
104 }
105 
106 #endif /* CONFIG_NS16550_MIN_FUNCTIONS */
107