blob: da5f9a21f46662f250d9d0db7f2c94a53cc84c02 [file] [log] [blame]
Alison Wang427eba72013-05-27 22:55:45 +00001/*
2 * Copyright 2013 Freescale Semiconductor, Inc.
3 *
Wolfgang Denk1a459662013-07-08 09:37:19 +02004 * SPDX-License-Identifier: GPL-2.0+
Alison Wang427eba72013-05-27 22:55:45 +00005 */
6
7#include <common.h>
8#include <watchdog.h>
9#include <asm/io.h>
10#include <serial.h>
11#include <linux/compiler.h>
12#include <asm/arch/imx-regs.h>
13#include <asm/arch/clock.h>
14
15#define US1_TDRE (1 << 7)
16#define US1_RDRF (1 << 5)
17#define UC2_TE (1 << 3)
18#define UC2_RE (1 << 2)
19
20DECLARE_GLOBAL_DATA_PTR;
21
22struct lpuart_fsl *base = (struct lpuart_fsl *)LPUART_BASE;
23
24static void lpuart_serial_setbrg(void)
25{
26 u32 clk = mxc_get_clock(MXC_UART_CLK);
27 u16 sbr;
28
29 if (!gd->baudrate)
30 gd->baudrate = CONFIG_BAUDRATE;
31
32 sbr = (u16)(clk / (16 * gd->baudrate));
33 /* place adjustment later - n/32 BRFA */
34
35 __raw_writeb(sbr >> 8, &base->ubdh);
36 __raw_writeb(sbr & 0xff, &base->ubdl);
37}
38
39static int lpuart_serial_getc(void)
40{
41 u8 status;
42
43 while (!(__raw_readb(&base->us1) & US1_RDRF))
44 WATCHDOG_RESET();
45
46 status = __raw_readb(&base->us1);
47 status |= US1_RDRF;
48 __raw_writeb(status, &base->us1);
49
50 return __raw_readb(&base->ud);
51}
52
53static void lpuart_serial_putc(const char c)
54{
55 if (c == '\n')
56 serial_putc('\r');
57
58 while (!(__raw_readb(&base->us1) & US1_TDRE))
59 WATCHDOG_RESET();
60
61 __raw_writeb(c, &base->ud);
62}
63
64/*
65 * Test whether a character is in the RX buffer
66 */
67static int lpuart_serial_tstc(void)
68{
69 if (__raw_readb(&base->urcfifo) == 0)
70 return 0;
71
72 return 1;
73}
74
75/*
76 * Initialise the serial port with the given baudrate. The settings
77 * are always 8 data bits, no parity, 1 stop bit, no start bits.
78 */
79static int lpuart_serial_init(void)
80{
81 u8 ctrl;
82
83 ctrl = __raw_readb(&base->uc2);
84 ctrl &= ~UC2_RE;
85 ctrl &= ~UC2_TE;
86 __raw_writeb(ctrl, &base->uc2);
87
88 __raw_writeb(0, &base->umodem);
89 __raw_writeb(0, &base->uc1);
90
91 /* provide data bits, parity, stop bit, etc */
92
93 serial_setbrg();
94
95 __raw_writeb(UC2_RE | UC2_TE, &base->uc2);
96
97 return 0;
98}
99
100static struct serial_device lpuart_serial_drv = {
101 .name = "lpuart_serial",
102 .start = lpuart_serial_init,
103 .stop = NULL,
104 .setbrg = lpuart_serial_setbrg,
105 .putc = lpuart_serial_putc,
106 .puts = default_serial_puts,
107 .getc = lpuart_serial_getc,
108 .tstc = lpuart_serial_tstc,
109};
110
111void lpuart_serial_initialize(void)
112{
113 serial_register(&lpuart_serial_drv);
114}
115
116__weak struct serial_device *default_serial_console(void)
117{
118 return &lpuart_serial_drv;
119}