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