xref: /openbmc/u-boot/drivers/serial/ns16550.c (revision ccf7988b)
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 #elif defined(CONFIG_SYS_NS16550_MEM32) && (CONFIG_SYS_NS16550_REG_SIZE > 0)
23 #define serial_out(x, y)	out_be32(y, x)
24 #define serial_in(y)		in_be32(y)
25 #elif defined(CONFIG_SYS_NS16550_MEM32) && (CONFIG_SYS_NS16550_REG_SIZE < 0)
26 #define serial_out(x, y)	out_le32(y, x)
27 #define serial_in(y)		in_le32(y)
28 #else
29 #define serial_out(x, y)	writeb(x, y)
30 #define serial_in(y)		readb(y)
31 #endif
32 
33 #ifndef CONFIG_SYS_NS16550_IER
34 #define CONFIG_SYS_NS16550_IER  0x00
35 #endif /* CONFIG_SYS_NS16550_IER */
36 
37 void NS16550_init(NS16550_t com_port, int baud_divisor)
38 {
39 	serial_out(CONFIG_SYS_NS16550_IER, &com_port->ier);
40 #if defined(CONFIG_OMAP) && !defined(CONFIG_OMAP3_ZOOM2)
41 	serial_out(0x7, &com_port->mdr1);	/* mode select reset TL16C750*/
42 #endif
43 	serial_out(UART_LCR_BKSE | UART_LCRVAL, (ulong)&com_port->lcr);
44 	serial_out(0, &com_port->dll);
45 	serial_out(0, &com_port->dlm);
46 	serial_out(UART_LCRVAL, &com_port->lcr);
47 	serial_out(UART_MCRVAL, &com_port->mcr);
48 	serial_out(UART_FCRVAL, &com_port->fcr);
49 	serial_out(UART_LCR_BKSE | UART_LCRVAL, &com_port->lcr);
50 	serial_out(baud_divisor & 0xff, &com_port->dll);
51 	serial_out((baud_divisor >> 8) & 0xff, &com_port->dlm);
52 	serial_out(UART_LCRVAL, &com_port->lcr);
53 #if defined(CONFIG_OMAP) && !defined(CONFIG_OMAP3_ZOOM2)
54 #if defined(CONFIG_APTIX)
55 	/* /13 mode so Aptix 6MHz can hit 115200 */
56 	serial_out(3, &com_port->mdr1);
57 #else
58 	/* /16 is proper to hit 115200 with 48MHz */
59 	serial_out(0, &com_port->mdr1);
60 #endif
61 #endif /* CONFIG_OMAP */
62 }
63 
64 #ifndef CONFIG_NS16550_MIN_FUNCTIONS
65 void NS16550_reinit(NS16550_t com_port, int baud_divisor)
66 {
67 	serial_out(CONFIG_SYS_NS16550_IER, &com_port->ier);
68 	serial_out(UART_LCR_BKSE | UART_LCRVAL, &com_port->lcr);
69 	serial_out(0, &com_port->dll);
70 	serial_out(0, &com_port->dlm);
71 	serial_out(UART_LCRVAL, &com_port->lcr);
72 	serial_out(UART_MCRVAL, &com_port->mcr);
73 	serial_out(UART_FCRVAL, &com_port->fcr);
74 	serial_out(UART_LCR_BKSE, &com_port->lcr);
75 	serial_out(baud_divisor & 0xff, &com_port->dll);
76 	serial_out((baud_divisor >> 8) & 0xff, &com_port->dlm);
77 	serial_out(UART_LCRVAL, &com_port->lcr);
78 }
79 #endif /* CONFIG_NS16550_MIN_FUNCTIONS */
80 
81 void NS16550_putc(NS16550_t com_port, char c)
82 {
83 	while ((serial_in(&com_port->lsr) & UART_LSR_THRE) == 0)
84 		;
85 	serial_out(c, &com_port->thr);
86 
87 	/*
88 	 * Call watchdog_reset() upon newline. This is done here in putc
89 	 * since the environment code uses a single puts() to print the complete
90 	 * environment upon "printenv". So we can't put this watchdog call
91 	 * in puts().
92 	 */
93 	if (c == '\n')
94 		WATCHDOG_RESET();
95 }
96 
97 #ifndef CONFIG_NS16550_MIN_FUNCTIONS
98 char NS16550_getc(NS16550_t com_port)
99 {
100 	while ((serial_in(&com_port->lsr) & UART_LSR_DR) == 0) {
101 #ifdef CONFIG_USB_TTY
102 		extern void usbtty_poll(void);
103 		usbtty_poll();
104 #endif
105 		WATCHDOG_RESET();
106 	}
107 	return serial_in(&com_port->rbr);
108 }
109 
110 int NS16550_tstc(NS16550_t com_port)
111 {
112 	return (serial_in(&com_port->lsr) & UART_LSR_DR) != 0;
113 }
114 
115 #endif /* CONFIG_NS16550_MIN_FUNCTIONS */
116