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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; | |
94b5400e | 41 | writeb(arc_console_baud & 0xff, ®s->baudl); |
1d568c76 AB |
42 | |
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) | |
94b5400e | 53 | writeb((arc_console_baud & 0xff00) >> 8, ®s->baudh); |
1d568c76 | 54 | else |
94b5400e | 55 | writeb(1, ®s->baudh); |
1d568c76 | 56 | #else |
94b5400e | 57 | writeb((arc_console_baud & 0xff00) >> 8, ®s->baudh); |
1d568c76 | 58 | #endif |
22a240c3 AB |
59 | } |
60 | ||
61 | static int arc_serial_init(void) | |
62 | { | |
63 | regs = (struct arc_serial_regs *)CONFIG_ARC_UART_BASE; | |
64 | serial_setbrg(); | |
65 | return 0; | |
66 | } | |
67 | ||
68 | static void arc_serial_putc(const char c) | |
69 | { | |
70 | if (c == '\n') | |
71 | arc_serial_putc('\r'); | |
72 | ||
94b5400e | 73 | while (!(readb(®s->status) & UART_TXEMPTY)) |
22a240c3 AB |
74 | ; |
75 | ||
94b5400e | 76 | writeb(c, ®s->data); |
22a240c3 AB |
77 | } |
78 | ||
79 | static int arc_serial_tstc(void) | |
80 | { | |
94b5400e | 81 | return !(readb(®s->status) & UART_RXEMPTY); |
22a240c3 AB |
82 | } |
83 | ||
84 | static int arc_serial_getc(void) | |
85 | { | |
86 | while (!arc_serial_tstc()) | |
87 | ; | |
88 | ||
89 | /* Check for overflow errors */ | |
94b5400e | 90 | if (readb(®s->status) & UART_OVERFLOW_ERR) |
22a240c3 AB |
91 | return 0; |
92 | ||
94b5400e | 93 | return readb(®s->data) & 0xFF; |
22a240c3 AB |
94 | } |
95 | ||
22a240c3 AB |
96 | static 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, | |
1cb8393a | 102 | .puts = default_serial_puts, |
22a240c3 AB |
103 | .getc = arc_serial_getc, |
104 | .tstc = arc_serial_tstc, | |
105 | }; | |
106 | ||
107 | void 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 | } |