summaryrefslogtreecommitdiffstats
path: root/arch/x86_64/kernel/early_printk.c
blob: 47b6d90349da905f226709aaf29c9ff48e501741 (plain)
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
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
#include <linux/console.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/string.h>
#include <linux/screen_info.h>
#include <asm/io.h>
#include <asm/processor.h>
#include <asm/fcntl.h>

/* Simple VGA output */

#ifdef __i386__
#include <asm/setup.h>
#define VGABASE		(__ISA_IO_base + 0xb8000)
#else
#include <asm/bootsetup.h>
#define VGABASE		((void __iomem *)0xffffffff800b8000UL)
#endif

static int max_ypos = 25, max_xpos = 80;
static int current_ypos = 25, current_xpos = 0;

static void early_vga_write(struct console *con, const char *str, unsigned n)
{
	char c;
	int  i, k, j;

	while ((c = *str++) != '\0' && n-- > 0) {
		if (current_ypos >= max_ypos) {
			/* scroll 1 line up */
			for (k = 1, j = 0; k < max_ypos; k++, j++) {
				for (i = 0; i < max_xpos; i++) {
					writew(readw(VGABASE+2*(max_xpos*k+i)),
					       VGABASE + 2*(max_xpos*j + i));
				}
			}
			for (i = 0; i < max_xpos; i++)
				writew(0x720, VGABASE + 2*(max_xpos*j + i));
			current_ypos = max_ypos-1;
		}
		if (c == '\n') {
			current_xpos = 0;
			current_ypos++;
		} else if (c != '\r')  {
			writew(((0x7 << 8) | (unsigned short) c),
			       VGABASE + 2*(max_xpos*current_ypos +
						current_xpos++));
			if (current_xpos >= max_xpos) {
				current_xpos = 0;
				current_ypos++;
			}
		}
	}
}

static struct console early_vga_console = {
	.name =		"earlyvga",
	.write =	early_vga_write,
	.flags =	CON_PRINTBUFFER,
	.index =	-1,
};

/* Serial functions loosely based on a similar package from Klaus P. Gerlicher */

static int early_serial_base = 0x3f8;  /* ttyS0 */

#define XMTRDY          0x20

#define DLAB		0x80

#define TXR             0       /*  Transmit register (WRITE) */
#define RXR             0       /*  Receive register  (READ)  */
#define IER             1       /*  Interrupt Enable          */
#define IIR             2       /*  Interrupt ID              */
#define FCR             2       /*  FIFO control              */
#define LCR             3       /*  Line control              */
#define MCR             4       /*  Modem control             */
#define LSR             5       /*  Line Status               */
#define MSR             6       /*  Modem Status              */
#define DLL             0       /*  Divisor Latch Low         */
#define DLH             1       /*  Divisor latch High        */

static int early_serial_putc(unsigned char ch)
{
	unsigned timeout = 0xffff;
	while ((inb(early_serial_base + LSR) & XMTRDY) == 0 && --timeout)
		cpu_relax();
	outb(ch, early_serial_base + TXR);
	return timeout ? 0 : -1;
}

static void early_serial_write(struct console *con, const char *s, unsigned n)
{
	while (*s && n-- > 0) {
		early_serial_putc(*s);
		if (*s == '\n')
			early_serial_putc('\r');
		s++;
	}
}

#define DEFAULT_BAUD 9600

static __init void early_serial_init(char *s)
{
	unsigned char c;
	unsigned divisor;
	unsigned baud = DEFAULT_BAUD;
	char *e;

	if (*s == ',')
		++s;

	if (*s) {
		unsigned port;
		if (!strncmp(s,"0x",2)) {
			early_serial_base = simple_strtoul(s, &e, 16);
		} else {
			static int bases[] = { 0x3f8, 0x2f8 };

			if (!strncmp(s,"ttyS",4))
				s += 4;
			port = simple_strtoul(s, &e, 10);
			if (port > 1 || s == e)
				port = 0;
			early_serial_base = bases[port];
		}
		s += strcspn(s, ",");
		if (*s == ',')
			s++;
	}

	outb(0x3, early_serial_base + LCR);	/* 8n1 */
	outb(0, early_serial_base + IER);	/* no interrupt */
	outb(0, early_serial_base + FCR);	/* no fifo */
	outb(0x3, early_serial_base + MCR);	/* DTR + RTS */

	if (*s) {
		baud = simple_strtoul(s, &e, 0);
		if (baud == 0 || s == e)
			baud = DEFAULT_BAUD;
	}

	divisor = 115200 / baud;
	c = inb(early_serial_base + LCR);
	outb(c | DLAB, early_serial_base + LCR);
	outb(divisor & 0xff, early_serial_base + DLL);
	outb((divisor >> 8) & 0xff, early_serial_base + DLH);
	outb(c & ~DLAB, early_serial_base + LCR);
}

static struct console early_serial_console = {
	.name =		"earlyser",
	.write =	early_serial_write,
	.flags =	CON_PRINTBUFFER,
	.index =	-1,
};

/* Console interface to a host file on AMD's SimNow! */

static int simnow_fd;

enum {
	MAGIC1 = 0xBACCD00A,
	MAGIC2 = 0xCA110000,
	XOPEN = 5,
	XWRITE = 4,
};

static noinline long simnow(long cmd, long a, long b, long c)
{
	long ret;
	asm volatile("cpuid" :
		     "=a" (ret) :
		     "b" (a), "c" (b), "d" (c), "0" (MAGIC1), "D" (cmd + MAGIC2));
	return ret;
}

void __init simnow_init(char *str)
{
	char *fn = "klog";
	if (*str == '=')
		fn = ++str;
	/* error ignored */
	simnow_fd = simnow(XOPEN, (unsigned long)fn, O_WRONLY|O_APPEND|O_CREAT, 0644);
}

static void simnow_write(struct console *con, const char *s, unsigned n)
{
	simnow(XWRITE, simnow_fd, (unsigned long)s, n);
}

static struct console simnow_console = {
	.name =		"simnow",
	.write =	simnow_write,
	.flags =	CON_PRINTBUFFER,
	.index =	-1,
};

/* Direct interface for emergencies */
struct console *early_console = &early_vga_console;
static int early_console_initialized = 0;

void early_printk(const char *fmt, ...)
{
	char buf[512];
	int n;
	va_list ap;

	va_start(ap,fmt);
	n = vscnprintf(buf,512,fmt,ap);
	early_console->write(early_console,buf,n);
	va_end(ap);
}

static int __initdata keep_early;

static int __init setup_early_printk(char *buf)
{
	if (!buf)
		return 0;

	if (early_console_initialized)
		return 0;
	early_console_initialized = 1;

	if (strstr(buf, "keep"))
		keep_early = 1;

	if (!strncmp(buf, "serial", 6)) {
		early_serial_init(buf + 6);
		early_console = &early_serial_console;
	} else if (!strncmp(buf, "ttyS", 4)) {
		early_serial_init(buf);
		early_console = &early_serial_console;
	} else if (!strncmp(buf, "vga", 3)
	           && SCREEN_INFO.orig_video_isVGA == 1) {
		max_xpos = SCREEN_INFO.orig_video_cols;
		max_ypos = SCREEN_INFO.orig_video_lines;
		current_ypos = SCREEN_INFO.orig_y;
		early_console = &early_vga_console;
 	} else if (!strncmp(buf, "simnow", 6)) {
 		simnow_init(buf + 6);
 		early_console = &simnow_console;
 		keep_early = 1;
	}
	register_console(early_console);
	return 0;
}

early_param("earlyprintk", setup_early_printk);

void __init disable_early_printk(void)
{
	if (!early_console_initialized || !early_console)
		return;
	if (!keep_early) {
		printk("disabling early console\n");
		unregister_console(early_console);
		early_console_initialized = 0;
	} else {
		printk("keeping early console\n");
	}
}