blob: 2ddbf32a507ace37bbd66d54402e0d3895b7785f [file] [log] [blame]
Alexey Brodkin22a240c2013-12-13 10:35:11 +04001/*
2 * Copyright (C) 2013 Synopsys, Inc. (www.synopsys.com)
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
7 *
8 */
9
10#include <common.h>
11#include <serial.h>
12
13DECLARE_GLOBAL_DATA_PTR;
14
15struct arc_serial_regs {
16 unsigned int id0;
17 unsigned int id1;
18 unsigned int id2;
19 unsigned int id3;
20 unsigned int data;
21 unsigned int status;
22 unsigned int baudl;
23 unsigned int baudh;
24};
25
26/* Bit definitions of STATUS register */
27#define UART_RXEMPTY (1 << 5)
28#define UART_OVERFLOW_ERR (1 << 1)
29#define UART_TXEMPTY (1 << 7)
30
31struct arc_serial_regs *regs;
32
33static void arc_serial_setbrg(void)
34{
35 int arc_console_baud;
36
37 if (!gd->baudrate)
38 gd->baudrate = CONFIG_BAUDRATE;
39
40 arc_console_baud = gd->cpu_clk / (gd->baudrate * 4) - 1;
Alexey Brodkin94b54002014-02-08 10:10:02 +040041 writeb(arc_console_baud & 0xff, &regs->baudl);
Alexey Brodkin1d568c72014-02-08 10:10:01 +040042
43#ifdef CONFIG_ARC
44 /*
45 * UART ISS(Instruction Set simulator) emulation has a subtle bug:
46 * A existing value of Baudh = 0 is used as a indication to startup
47 * it's internal state machine.
48 * Thus if baudh is set to 0, 2 times, it chokes.
49 * This happens with BAUD=115200 and the formaula above
50 * Until that is fixed, when running on ISS, we will set baudh to !0
51 */
52 if (gd->arch.running_on_hw)
Alexey Brodkin94b54002014-02-08 10:10:02 +040053 writeb((arc_console_baud & 0xff00) >> 8, &regs->baudh);
Alexey Brodkin1d568c72014-02-08 10:10:01 +040054 else
Alexey Brodkin94b54002014-02-08 10:10:02 +040055 writeb(1, &regs->baudh);
Alexey Brodkin1d568c72014-02-08 10:10:01 +040056#else
Alexey Brodkin94b54002014-02-08 10:10:02 +040057 writeb((arc_console_baud & 0xff00) >> 8, &regs->baudh);
Alexey Brodkin1d568c72014-02-08 10:10:01 +040058#endif
Alexey Brodkin22a240c2013-12-13 10:35:11 +040059}
60
61static int arc_serial_init(void)
62{
63 regs = (struct arc_serial_regs *)CONFIG_ARC_UART_BASE;
64 serial_setbrg();
65 return 0;
66}
67
68static void arc_serial_putc(const char c)
69{
70 if (c == '\n')
71 arc_serial_putc('\r');
72
Alexey Brodkin94b54002014-02-08 10:10:02 +040073 while (!(readb(&regs->status) & UART_TXEMPTY))
Alexey Brodkin22a240c2013-12-13 10:35:11 +040074 ;
75
Alexey Brodkin94b54002014-02-08 10:10:02 +040076 writeb(c, &regs->data);
Alexey Brodkin22a240c2013-12-13 10:35:11 +040077}
78
79static int arc_serial_tstc(void)
80{
Alexey Brodkin94b54002014-02-08 10:10:02 +040081 return !(readb(&regs->status) & UART_RXEMPTY);
Alexey Brodkin22a240c2013-12-13 10:35:11 +040082}
83
84static int arc_serial_getc(void)
85{
86 while (!arc_serial_tstc())
87 ;
88
89 /* Check for overflow errors */
Alexey Brodkin94b54002014-02-08 10:10:02 +040090 if (readb(&regs->status) & UART_OVERFLOW_ERR)
Alexey Brodkin22a240c2013-12-13 10:35:11 +040091 return 0;
92
Alexey Brodkin94b54002014-02-08 10:10:02 +040093 return readb(&regs->data) & 0xFF;
Alexey Brodkin22a240c2013-12-13 10:35:11 +040094}
95
Alexey Brodkin22a240c2013-12-13 10:35:11 +040096static struct serial_device arc_serial_drv = {
97 .name = "arc_serial",
98 .start = arc_serial_init,
99 .stop = NULL,
100 .setbrg = arc_serial_setbrg,
101 .putc = arc_serial_putc,
Axel Lin1cb83932014-02-08 15:04:58 +0800102 .puts = default_serial_puts,
Alexey Brodkin22a240c2013-12-13 10:35:11 +0400103 .getc = arc_serial_getc,
104 .tstc = arc_serial_tstc,
105};
106
107void arc_serial_initialize(void)
108{
109 serial_register(&arc_serial_drv);
110}
111
112__weak struct serial_device *default_serial_console(void)
113{
114 return &arc_serial_drv;
115}