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22a240c3 AB |
1 | /* |
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 | ||
13 | DECLARE_GLOBAL_DATA_PTR; | |
14 | ||
15 | struct 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 | ||
31 | struct arc_serial_regs *regs; | |
32 | ||
33 | static 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; | |
41 | writel(arc_console_baud & 0xff, ®s->baudl); | |
42 | writel((arc_console_baud & 0xff00) >> 8, ®s->baudh); | |
43 | } | |
44 | ||
45 | static int arc_serial_init(void) | |
46 | { | |
47 | regs = (struct arc_serial_regs *)CONFIG_ARC_UART_BASE; | |
48 | serial_setbrg(); | |
49 | return 0; | |
50 | } | |
51 | ||
52 | static void arc_serial_putc(const char c) | |
53 | { | |
54 | if (c == '\n') | |
55 | arc_serial_putc('\r'); | |
56 | ||
57 | while (!(readl(®s->status) & UART_TXEMPTY)) | |
58 | ; | |
59 | ||
60 | writel(c, ®s->data); | |
61 | } | |
62 | ||
63 | static int arc_serial_tstc(void) | |
64 | { | |
65 | return !(readl(®s->status) & UART_RXEMPTY); | |
66 | } | |
67 | ||
68 | static int arc_serial_getc(void) | |
69 | { | |
70 | while (!arc_serial_tstc()) | |
71 | ; | |
72 | ||
73 | /* Check for overflow errors */ | |
74 | if (readl(®s->status) & UART_OVERFLOW_ERR) | |
75 | return 0; | |
76 | ||
77 | return readl(®s->data) & 0xFF; | |
78 | } | |
79 | ||
80 | static void arc_serial_puts(const char *s) | |
81 | { | |
82 | while (*s) | |
83 | arc_serial_putc(*s++); | |
84 | } | |
85 | ||
86 | static struct serial_device arc_serial_drv = { | |
87 | .name = "arc_serial", | |
88 | .start = arc_serial_init, | |
89 | .stop = NULL, | |
90 | .setbrg = arc_serial_setbrg, | |
91 | .putc = arc_serial_putc, | |
92 | .puts = arc_serial_puts, | |
93 | .getc = arc_serial_getc, | |
94 | .tstc = arc_serial_tstc, | |
95 | }; | |
96 | ||
97 | void arc_serial_initialize(void) | |
98 | { | |
99 | serial_register(&arc_serial_drv); | |
100 | } | |
101 | ||
102 | __weak struct serial_device *default_serial_console(void) | |
103 | { | |
104 | return &arc_serial_drv; | |
105 | } |