[PATCH] x86: Some preparationary cleanup for stack trace
[linux-2.6] / arch / x86_64 / kernel / early_printk.c
1 #include <linux/console.h>
2 #include <linux/kernel.h>
3 #include <linux/init.h>
4 #include <linux/string.h>
5 #include <linux/screen_info.h>
6 #include <asm/io.h>
7 #include <asm/processor.h>
8 #include <asm/fcntl.h>
9
10 /* Simple VGA output */
11
12 #ifdef __i386__
13 #include <asm/setup.h>
14 #define VGABASE         (__ISA_IO_base + 0xb8000)
15 #else
16 #include <asm/bootsetup.h>
17 #define VGABASE         ((void __iomem *)0xffffffff800b8000UL)
18 #endif
19
20 static int max_ypos = 25, max_xpos = 80;
21 static int current_ypos = 25, current_xpos = 0;
22
23 static void early_vga_write(struct console *con, const char *str, unsigned n)
24 {
25         char c;
26         int  i, k, j;
27
28         while ((c = *str++) != '\0' && n-- > 0) {
29                 if (current_ypos >= max_ypos) {
30                         /* scroll 1 line up */
31                         for (k = 1, j = 0; k < max_ypos; k++, j++) {
32                                 for (i = 0; i < max_xpos; i++) {
33                                         writew(readw(VGABASE+2*(max_xpos*k+i)),
34                                                VGABASE + 2*(max_xpos*j + i));
35                                 }
36                         }
37                         for (i = 0; i < max_xpos; i++)
38                                 writew(0x720, VGABASE + 2*(max_xpos*j + i));
39                         current_ypos = max_ypos-1;
40                 }
41                 if (c == '\n') {
42                         current_xpos = 0;
43                         current_ypos++;
44                 } else if (c != '\r')  {
45                         writew(((0x7 << 8) | (unsigned short) c),
46                                VGABASE + 2*(max_xpos*current_ypos +
47                                                 current_xpos++));
48                         if (current_xpos >= max_xpos) {
49                                 current_xpos = 0;
50                                 current_ypos++;
51                         }
52                 }
53         }
54 }
55
56 static struct console early_vga_console = {
57         .name =         "earlyvga",
58         .write =        early_vga_write,
59         .flags =        CON_PRINTBUFFER,
60         .index =        -1,
61 };
62
63 /* Serial functions loosely based on a similar package from Klaus P. Gerlicher */
64
65 static int early_serial_base = 0x3f8;  /* ttyS0 */
66
67 #define XMTRDY          0x20
68
69 #define DLAB            0x80
70
71 #define TXR             0       /*  Transmit register (WRITE) */
72 #define RXR             0       /*  Receive register  (READ)  */
73 #define IER             1       /*  Interrupt Enable          */
74 #define IIR             2       /*  Interrupt ID              */
75 #define FCR             2       /*  FIFO control              */
76 #define LCR             3       /*  Line control              */
77 #define MCR             4       /*  Modem control             */
78 #define LSR             5       /*  Line Status               */
79 #define MSR             6       /*  Modem Status              */
80 #define DLL             0       /*  Divisor Latch Low         */
81 #define DLH             1       /*  Divisor latch High        */
82
83 static int early_serial_putc(unsigned char ch)
84 {
85         unsigned timeout = 0xffff;
86         while ((inb(early_serial_base + LSR) & XMTRDY) == 0 && --timeout)
87                 cpu_relax();
88         outb(ch, early_serial_base + TXR);
89         return timeout ? 0 : -1;
90 }
91
92 static void early_serial_write(struct console *con, const char *s, unsigned n)
93 {
94         while (*s && n-- > 0) {
95                 early_serial_putc(*s);
96                 if (*s == '\n')
97                         early_serial_putc('\r');
98                 s++;
99         }
100 }
101
102 #define DEFAULT_BAUD 9600
103
104 static __init void early_serial_init(char *s)
105 {
106         unsigned char c;
107         unsigned divisor;
108         unsigned baud = DEFAULT_BAUD;
109         char *e;
110
111         if (*s == ',')
112                 ++s;
113
114         if (*s) {
115                 unsigned port;
116                 if (!strncmp(s,"0x",2)) {
117                         early_serial_base = simple_strtoul(s, &e, 16);
118                 } else {
119                         static int bases[] = { 0x3f8, 0x2f8 };
120
121                         if (!strncmp(s,"ttyS",4))
122                                 s += 4;
123                         port = simple_strtoul(s, &e, 10);
124                         if (port > 1 || s == e)
125                                 port = 0;
126                         early_serial_base = bases[port];
127                 }
128                 s += strcspn(s, ",");
129                 if (*s == ',')
130                         s++;
131         }
132
133         outb(0x3, early_serial_base + LCR);     /* 8n1 */
134         outb(0, early_serial_base + IER);       /* no interrupt */
135         outb(0, early_serial_base + FCR);       /* no fifo */
136         outb(0x3, early_serial_base + MCR);     /* DTR + RTS */
137
138         if (*s) {
139                 baud = simple_strtoul(s, &e, 0);
140                 if (baud == 0 || s == e)
141                         baud = DEFAULT_BAUD;
142         }
143
144         divisor = 115200 / baud;
145         c = inb(early_serial_base + LCR);
146         outb(c | DLAB, early_serial_base + LCR);
147         outb(divisor & 0xff, early_serial_base + DLL);
148         outb((divisor >> 8) & 0xff, early_serial_base + DLH);
149         outb(c & ~DLAB, early_serial_base + LCR);
150 }
151
152 static struct console early_serial_console = {
153         .name =         "earlyser",
154         .write =        early_serial_write,
155         .flags =        CON_PRINTBUFFER,
156         .index =        -1,
157 };
158
159 /* Console interface to a host file on AMD's SimNow! */
160
161 static int simnow_fd;
162
163 enum {
164         MAGIC1 = 0xBACCD00A,
165         MAGIC2 = 0xCA110000,
166         XOPEN = 5,
167         XWRITE = 4,
168 };
169
170 static noinline long simnow(long cmd, long a, long b, long c)
171 {
172         long ret;
173         asm volatile("cpuid" :
174                      "=a" (ret) :
175                      "b" (a), "c" (b), "d" (c), "0" (MAGIC1), "D" (cmd + MAGIC2));
176         return ret;
177 }
178
179 void __init simnow_init(char *str)
180 {
181         char *fn = "klog";
182         if (*str == '=')
183                 fn = ++str;
184         /* error ignored */
185         simnow_fd = simnow(XOPEN, (unsigned long)fn, O_WRONLY|O_APPEND|O_CREAT, 0644);
186 }
187
188 static void simnow_write(struct console *con, const char *s, unsigned n)
189 {
190         simnow(XWRITE, simnow_fd, (unsigned long)s, n);
191 }
192
193 static struct console simnow_console = {
194         .name =         "simnow",
195         .write =        simnow_write,
196         .flags =        CON_PRINTBUFFER,
197         .index =        -1,
198 };
199
200 /* Direct interface for emergencies */
201 struct console *early_console = &early_vga_console;
202 static int early_console_initialized = 0;
203
204 void early_printk(const char *fmt, ...)
205 {
206         char buf[512];
207         int n;
208         va_list ap;
209
210         va_start(ap,fmt);
211         n = vscnprintf(buf,512,fmt,ap);
212         early_console->write(early_console,buf,n);
213         va_end(ap);
214 }
215
216 static int __initdata keep_early;
217
218 static int __init setup_early_printk(char *buf)
219 {
220         if (!buf)
221                 return 0;
222
223         if (early_console_initialized)
224                 return 0;
225         early_console_initialized = 1;
226
227         if (!strcmp(buf,"keep"))
228                 keep_early = 1;
229
230         if (!strncmp(buf, "serial", 6)) {
231                 early_serial_init(buf + 6);
232                 early_console = &early_serial_console;
233         } else if (!strncmp(buf, "ttyS", 4)) {
234                 early_serial_init(buf);
235                 early_console = &early_serial_console;
236         } else if (!strncmp(buf, "vga", 3)
237                    && SCREEN_INFO.orig_video_isVGA == 1) {
238                 max_xpos = SCREEN_INFO.orig_video_cols;
239                 max_ypos = SCREEN_INFO.orig_video_lines;
240                 current_ypos = SCREEN_INFO.orig_y;
241                 early_console = &early_vga_console;
242         } else if (!strncmp(buf, "simnow", 6)) {
243                 simnow_init(buf + 6);
244                 early_console = &simnow_console;
245                 keep_early = 1;
246         }
247         register_console(early_console);
248         return 0;
249 }
250
251 early_param("earlyprintk", setup_early_printk);
252
253 void __init disable_early_printk(void)
254 {
255         if (!early_console_initialized || !early_console)
256                 return;
257         if (!keep_early) {
258                 printk("disabling early console\n");
259                 unregister_console(early_console);
260                 early_console_initialized = 0;
261         } else {
262                 printk("keeping early console\n");
263         }
264 }
265