1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
|
#include <stdbool.h>
#include <stdlib.h>
#include <stdio.h>
#include <console.h>
#include <sys/io.h>
#include <x86/cpu.h>
#include <syslinux/config.h>
#include "serial.h"
enum {
THR = 0,
RBR = 0,
DLL = 0,
DLM = 1,
IER = 1,
IIR = 2,
FCR = 2,
LCR = 3,
MCR = 4,
LSR = 5,
MSR = 6,
SCR = 7,
};
int serial_init(struct serial_if *sif, const char *argv[])
{
const struct syslinux_serial_console_info *sci
= syslinux_serial_console_info();
uint16_t port;
unsigned int divisor;
uint8_t dll, dlm, lcr;
if (!argv[0]) {
if (sci->iobase) {
port = sci->iobase;
} else {
printf("No port number specified and not using serial console!\n");
return -1;
}
} else {
port = strtoul(argv[0], NULL, 0);
if (port <= 3) {
uint16_t addr = ((uint16_t *)0x400)[port];
if (!addr) {
printf("No serial port address found!\n");
return -1;
}
printf("Serial port %u is at 0x%04x\n", port, addr);
port = addr;
}
}
sif->port = port;
sif->console = false;
divisor = 1; /* Default speed = 115200 bps */
/* Check to see if this is the same as the serial console */
if (port == sci->iobase) {
/* Overlaying the console... */
sif->console = true;
/* Default to already configured speed */
divisor = sci->divisor;
/* Shut down I/O to the console for the time being */
openconsole(&dev_null_r, &dev_null_w);
}
if (argv[0] && argv[1])
divisor = 115200/strtoul(argv[1], NULL, 0);
cli(); /* Just in case... */
/* Save old register settings */
sif->old.lcr = inb(port + LCR);
sif->old.mcr = inb(port + MCR);
sif->old.iir = inb(port + IIR);
/* Set speed */
outb(0x83, port + LCR); /* Enable divisor access */
sif->old.dll = inb(port + DLL);
sif->old.dlm = inb(port + DLM);
outb(divisor, port + DLL);
outb(divisor >> 8, port + DLM);
(void)inb(port + IER); /* Synchronize */
dll = inb(port + DLL);
dlm = inb(port + DLM);
lcr = inb(port + LCR);
outb(0x03, port + LCR); /* Enable data access, n81 */
(void)inb(port + IER); /* Synchronize */
sif->old.ier = inb(port + IER);
/* Disable interrupts */
outb(0, port + IER);
sti();
if (dll != (uint8_t)divisor ||
dlm != (uint8_t)(divisor >> 8) ||
lcr != 0x83) {
serial_cleanup(sif);
printf("No serial port detected!\n");
return -1; /* This doesn't look like a serial port */
}
/* Enable 16550A FIFOs if available */
outb(0x01, port + FCR); /* Enable FIFO */
(void)inb(port + IER); /* Synchronize */
if (inb(port + IIR) < 0xc0)
outb(0x00, port + FCR); /* Disable FIFOs if non-functional */
(void)inb(port + IER); /* Synchronize */
return 0;
}
void serial_write(struct serial_if *sif, const void *data, size_t n)
{
uint16_t port = sif->port;
const char *p = data;
uint8_t lsr;
while (n--) {
do {
lsr = inb(port + LSR);
} while (!(lsr & 0x20));
outb(*p++, port + THR);
}
}
void serial_read(struct serial_if *sif, void *data, size_t n)
{
uint16_t port = sif->port;
char *p = data;
uint8_t lsr;
while (n--) {
do {
lsr = inb(port + LSR);
} while (!(lsr & 0x01));
*p++ = inb(port + RBR);
}
}
void serial_cleanup(struct serial_if *sif)
{
uint16_t port = sif->port;
outb(0x83, port + LCR);
(void)inb(port + IER);
outb(sif->old.dll, port + DLL);
outb(sif->old.dlm, port + DLM);
(void)inb(port + IER);
outb(sif->old.lcr & 0x7f, port + LCR);
(void)inb(port + IER);
outb(sif->old.mcr, port + MCR);
outb(sif->old.ier, port + IER);
if (sif->old.iir < 0xc0)
outb(0x00, port + FCR); /* Disable FIFOs */
/* Re-enable console messages, if we shut them down */
if (sif->console)
openconsole(&dev_null_r, &dev_stdcon_w);
}
|
