xref: /openbmc/u-boot/drivers/serial/ns16550.c (revision 9fc2ed40)
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 #if defined(CONFIG_K2HK_EVM)
34 #define UART_REG_VAL_PWREMU_MGMT_UART_DISABLE   0
35 #define UART_REG_VAL_PWREMU_MGMT_UART_ENABLE ((1 << 14) | (1 << 13) | (1 << 0))
36 #endif
37 
38 #ifndef CONFIG_SYS_NS16550_IER
39 #define CONFIG_SYS_NS16550_IER  0x00
40 #endif /* CONFIG_SYS_NS16550_IER */
41 
42 void NS16550_init(NS16550_t com_port, int baud_divisor)
43 {
44 #if (defined(CONFIG_SPL_BUILD) && defined(CONFIG_OMAP34XX))
45 	/*
46 	 * On some OMAP3 devices when UART3 is configured for boot mode before
47 	 * SPL starts only THRE bit is set. We have to empty the transmitter
48 	 * before initialization starts.
49 	 */
50 	if ((serial_in(&com_port->lsr) & (UART_LSR_TEMT | UART_LSR_THRE))
51 	     == UART_LSR_THRE) {
52 		serial_out(UART_LCR_DLAB, &com_port->lcr);
53 		serial_out(baud_divisor & 0xff, &com_port->dll);
54 		serial_out((baud_divisor >> 8) & 0xff, &com_port->dlm);
55 		serial_out(UART_LCRVAL, &com_port->lcr);
56 		serial_out(0, &com_port->mdr1);
57 	}
58 #endif
59 
60 	while (!(serial_in(&com_port->lsr) & UART_LSR_TEMT))
61 		;
62 
63 	serial_out(CONFIG_SYS_NS16550_IER, &com_port->ier);
64 #if defined(CONFIG_OMAP) || defined(CONFIG_AM33XX) || \
65 			defined(CONFIG_TI81XX) || defined(CONFIG_AM43XX)
66 	serial_out(0x7, &com_port->mdr1);	/* mode select reset TL16C750*/
67 #endif
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 | UART_LCRVAL, &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 #if (defined(CONFIG_OMAP) && !defined(CONFIG_OMAP3_ZOOM2)) || \
79 	defined(CONFIG_AM33XX) || defined(CONFIG_SOC_DA8XX) || \
80 	defined(CONFIG_TI81XX) || defined(CONFIG_AM43XX)
81 
82 	/* /16 is proper to hit 115200 with 48MHz */
83 	serial_out(0, &com_port->mdr1);
84 #endif /* CONFIG_OMAP */
85 #if defined(CONFIG_K2HK_EVM)
86 	serial_out(UART_REG_VAL_PWREMU_MGMT_UART_ENABLE, &com_port->regC);
87 #endif
88 }
89 
90 #ifndef CONFIG_NS16550_MIN_FUNCTIONS
91 void NS16550_reinit(NS16550_t com_port, int baud_divisor)
92 {
93 	serial_out(CONFIG_SYS_NS16550_IER, &com_port->ier);
94 	serial_out(UART_LCR_BKSE | UART_LCRVAL, &com_port->lcr);
95 	serial_out(0, &com_port->dll);
96 	serial_out(0, &com_port->dlm);
97 	serial_out(UART_LCRVAL, &com_port->lcr);
98 	serial_out(UART_MCRVAL, &com_port->mcr);
99 	serial_out(UART_FCRVAL, &com_port->fcr);
100 	serial_out(UART_LCR_BKSE, &com_port->lcr);
101 	serial_out(baud_divisor & 0xff, &com_port->dll);
102 	serial_out((baud_divisor >> 8) & 0xff, &com_port->dlm);
103 	serial_out(UART_LCRVAL, &com_port->lcr);
104 }
105 #endif /* CONFIG_NS16550_MIN_FUNCTIONS */
106 
107 void NS16550_putc(NS16550_t com_port, char c)
108 {
109 	while ((serial_in(&com_port->lsr) & UART_LSR_THRE) == 0)
110 		;
111 	serial_out(c, &com_port->thr);
112 
113 	/*
114 	 * Call watchdog_reset() upon newline. This is done here in putc
115 	 * since the environment code uses a single puts() to print the complete
116 	 * environment upon "printenv". So we can't put this watchdog call
117 	 * in puts().
118 	 */
119 	if (c == '\n')
120 		WATCHDOG_RESET();
121 }
122 
123 #ifndef CONFIG_NS16550_MIN_FUNCTIONS
124 char NS16550_getc(NS16550_t com_port)
125 {
126 	while ((serial_in(&com_port->lsr) & UART_LSR_DR) == 0) {
127 #if !defined(CONFIG_SPL_BUILD) && defined(CONFIG_USB_TTY)
128 		extern void usbtty_poll(void);
129 		usbtty_poll();
130 #endif
131 		WATCHDOG_RESET();
132 	}
133 	return serial_in(&com_port->rbr);
134 }
135 
136 int NS16550_tstc(NS16550_t com_port)
137 {
138 	return (serial_in(&com_port->lsr) & UART_LSR_DR) != 0;
139 }
140 
141 #endif /* CONFIG_NS16550_MIN_FUNCTIONS */
142