Commit | Line | Data |
---|---|---|
f4ed2877 YL |
1 | #include "boot.h" |
2 | ||
3 | #define DEFAULT_SERIAL_PORT 0x3f8 /* ttyS0 */ | |
4 | ||
f4ed2877 YL |
5 | #define DLAB 0x80 |
6 | ||
7 | #define TXR 0 /* Transmit register (WRITE) */ | |
8 | #define RXR 0 /* Receive register (READ) */ | |
9 | #define IER 1 /* Interrupt Enable */ | |
10 | #define IIR 2 /* Interrupt ID */ | |
11 | #define FCR 2 /* FIFO control */ | |
12 | #define LCR 3 /* Line control */ | |
13 | #define MCR 4 /* Modem control */ | |
14 | #define LSR 5 /* Line Status */ | |
15 | #define MSR 6 /* Modem Status */ | |
16 | #define DLL 0 /* Divisor Latch Low */ | |
17 | #define DLH 1 /* Divisor latch High */ | |
18 | ||
19 | #define DEFAULT_BAUD 9600 | |
20 | ||
21 | static void early_serial_init(int port, int baud) | |
22 | { | |
23 | unsigned char c; | |
24 | unsigned divisor; | |
25 | ||
26 | outb(0x3, port + LCR); /* 8n1 */ | |
27 | outb(0, port + IER); /* no interrupt */ | |
28 | outb(0, port + FCR); /* no fifo */ | |
29 | outb(0x3, port + MCR); /* DTR + RTS */ | |
30 | ||
31 | divisor = 115200 / baud; | |
32 | c = inb(port + LCR); | |
33 | outb(c | DLAB, port + LCR); | |
34 | outb(divisor & 0xff, port + DLL); | |
35 | outb((divisor >> 8) & 0xff, port + DLH); | |
36 | outb(c & ~DLAB, port + LCR); | |
37 | ||
38 | early_serial_base = port; | |
39 | } | |
40 | ||
41 | static void parse_earlyprintk(void) | |
42 | { | |
43 | int baud = DEFAULT_BAUD; | |
44 | char arg[32]; | |
45 | int pos = 0; | |
46 | int port = 0; | |
47 | ||
48 | if (cmdline_find_option("earlyprintk", arg, sizeof arg) > 0) { | |
49 | char *e; | |
50 | ||
51 | if (!strncmp(arg, "serial", 6)) { | |
52 | port = DEFAULT_SERIAL_PORT; | |
53 | pos += 6; | |
54 | } | |
55 | ||
56 | if (arg[pos] == ',') | |
57 | pos++; | |
58 | ||
74b3c444 YL |
59 | /* |
60 | * make sure we have | |
61 | * "serial,0x3f8,115200" | |
62 | * "serial,ttyS0,115200" | |
63 | * "ttyS0,115200" | |
64 | */ | |
65 | if (pos == 7 && !strncmp(arg + pos, "0x", 2)) { | |
66 | port = simple_strtoull(arg + pos, &e, 16); | |
67 | if (port == 0 || arg + pos == e) | |
68 | port = DEFAULT_SERIAL_PORT; | |
69 | else | |
70 | pos = e - arg; | |
71 | } else if (!strncmp(arg + pos, "ttyS", 4)) { | |
f4ed2877 YL |
72 | static const int bases[] = { 0x3f8, 0x2f8 }; |
73 | int idx = 0; | |
74 | ||
b3463001 AK |
75 | /* += strlen("ttyS"); */ |
76 | pos += 4; | |
f4ed2877 YL |
77 | |
78 | if (arg[pos++] == '1') | |
79 | idx = 1; | |
80 | ||
81 | port = bases[idx]; | |
82 | } | |
83 | ||
84 | if (arg[pos] == ',') | |
85 | pos++; | |
86 | ||
87 | baud = simple_strtoull(arg + pos, &e, 0); | |
88 | if (baud == 0 || arg + pos == e) | |
89 | baud = DEFAULT_BAUD; | |
90 | } | |
91 | ||
92 | if (port) | |
93 | early_serial_init(port, baud); | |
94 | } | |
95 | ||
96 | #define BASE_BAUD (1843200/16) | |
97 | static unsigned int probe_baud(int port) | |
98 | { | |
99 | unsigned char lcr, dll, dlh; | |
100 | unsigned int quot; | |
101 | ||
102 | lcr = inb(port + LCR); | |
103 | outb(lcr | DLAB, port + LCR); | |
104 | dll = inb(port + DLL); | |
105 | dlh = inb(port + DLH); | |
106 | outb(lcr, port + LCR); | |
107 | quot = (dlh << 8) | dll; | |
108 | ||
109 | return BASE_BAUD / quot; | |
110 | } | |
111 | ||
112 | static void parse_console_uart8250(void) | |
113 | { | |
114 | char optstr[64], *options; | |
115 | int baud = DEFAULT_BAUD; | |
116 | int port = 0; | |
117 | ||
118 | /* | |
119 | * console=uart8250,io,0x3f8,115200n8 | |
120 | * need to make sure it is last one console ! | |
121 | */ | |
122 | if (cmdline_find_option("console", optstr, sizeof optstr) <= 0) | |
123 | return; | |
124 | ||
125 | options = optstr; | |
126 | ||
127 | if (!strncmp(options, "uart8250,io,", 12)) | |
128 | port = simple_strtoull(options + 12, &options, 0); | |
129 | else if (!strncmp(options, "uart,io,", 8)) | |
130 | port = simple_strtoull(options + 8, &options, 0); | |
131 | else | |
132 | return; | |
133 | ||
134 | if (options && (options[0] == ',')) | |
135 | baud = simple_strtoull(options + 1, &options, 0); | |
136 | else | |
137 | baud = probe_baud(port); | |
138 | ||
139 | if (port) | |
140 | early_serial_init(port, baud); | |
141 | } | |
142 | ||
143 | void console_init(void) | |
144 | { | |
145 | parse_earlyprintk(); | |
146 | ||
147 | if (!early_serial_base) | |
148 | parse_console_uart8250(); | |
149 | } |