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/tty.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 #define MAX_YPOS        max_ypos
  21 #define MAX_XPOS        max_xpos
  22
  23 static int max_ypos = 25, max_xpos = 80;
  24 static int current_ypos = 1, current_xpos = 0;
  25
  26 static void early_vga_write(struct console *con, const char *str, unsigned n)
  27 {
  28         char c;
  29         int  i, k, j;
  30
  31         while ((c = *str++) != '\0' && n-- > 0) {
  32                 if (current_ypos >= MAX_YPOS) {
  33                         /* scroll 1 line up */
  34                         for (k = 1, j = 0; k < MAX_YPOS; k++, j++) {
  35                                 for (i = 0; i < MAX_XPOS; i++) {
  36                                         writew(readw(VGABASE + 2*(MAX_XPOS*k + i)),
  37                                                VGABASE + 2*(MAX_XPOS*j + i));
  38                                 }
  39                         }
  40                         for (i = 0; i < MAX_XPOS; i++)
  41                                 writew(0x720, VGABASE + 2*(MAX_XPOS*j + i));
  42                         current_ypos = MAX_YPOS-1;
  43                 }
  44                 if (c == '\n') {
  45                         current_xpos = 0;
  46                         current_ypos++;
  47                 } else if (c != '\r')  {
  48                         writew(((0x7 << 8) | (unsigned short) c),
  49                                VGABASE + 2*(MAX_XPOS*current_ypos +
  50                                                 current_xpos++));
  51                         if (current_xpos >= MAX_XPOS) {
  52                                 current_xpos = 0;
  53                                 current_ypos++;
  54                         }
  55                 }
  56         }
  57 }
  58
  59 static struct console early_vga_console = {
  60         .name =         "earlyvga",
  61         .write =        early_vga_write,
  62         .flags =        CON_PRINTBUFFER,
  63         .index =        -1,
  64 };
  65
  66 /* Serial functions loosely based on a similar package from Klaus P. Gerlicher */
  67
  68 static int early_serial_base = 0x3f8;  /* ttyS0 */
  69
  70 #define XMTRDY          0x20
  71
  72 #define DLAB            0x80
  73
  74 #define TXR             0       /*  Transmit register (WRITE) */
  75 #define RXR             0       /*  Receive register  (READ)  */
  76 #define IER             1       /*  Interrupt Enable          */
  77 #define IIR             2       /*  Interrupt ID              */
  78 #define FCR             2       /*  FIFO control              */
  79 #define LCR             3       /*  Line control              */
  80 #define MCR             4       /*  Modem control             */
  81 #define LSR             5       /*  Line Status               */
  82 #define MSR             6       /*  Modem Status              */
  83 #define DLL             0       /*  Divisor Latch Low         */
  84 #define DLH             1       /*  Divisor latch High        */
  85
  86 static int early_serial_putc(unsigned char ch)
  87 {
  88         unsigned timeout = 0xffff;
  89         while ((inb(early_serial_base + LSR) & XMTRDY) == 0 && --timeout)
  90                 cpu_relax();
  91         outb(ch, early_serial_base + TXR);
  92         return timeout ? 0 : -1;
  93 }
  94
  95 static void early_serial_write(struct console *con, const char *s, unsigned n)
  96 {
  97         while (*s && n-- > 0) {
  98                 early_serial_putc(*s);
  99                 if (*s == '\n')
 100                         early_serial_putc('\r');
 101                 s++;
 102         }
 103 }
 104
 105 #define DEFAULT_BAUD 9600
 106
 107 static __init void early_serial_init(char *s)
 108 {
 109         unsigned char c;
 110         unsigned divisor;
 111         unsigned baud = DEFAULT_BAUD;
 112         char *e;
 113
 114         if (*s == ',')
 115                 ++s;
 116
 117         if (*s) {
 118                 unsigned port;
 119                 if (!strncmp(s,"0x",2)) {
 120                         early_serial_base = simple_strtoul(s, &e, 16);
 121                 } else {
 122                         static int bases[] = { 0x3f8, 0x2f8 };
 123
 124                         if (!strncmp(s,"ttyS",4))
 125                                 s += 4;
 126                         port = simple_strtoul(s, &e, 10);
 127                         if (port > 1 || s == e)
 128                                 port = 0;
 129                         early_serial_base = bases[port];
 130                 }
 131                 s += strcspn(s, ",");
 132                 if (*s == ',')
 133                         s++;
 134         }
 135
 136         outb(0x3, early_serial_base + LCR);     /* 8n1 */
 137         outb(0, early_serial_base + IER);       /* no interrupt */
 138         outb(0, early_serial_base + FCR);       /* no fifo */
 139         outb(0x3, early_serial_base + MCR);     /* DTR + RTS */
 140
 141         if (*s) {
 142                 baud = simple_strtoul(s, &e, 0);
 143                 if (baud == 0 || s == e)
 144                         baud = DEFAULT_BAUD;
 145         }
 146
 147         divisor = 115200 / baud;
 148         c = inb(early_serial_base + LCR);
 149         outb(c | DLAB, early_serial_base + LCR);
 150         outb(divisor & 0xff, early_serial_base + DLL);
 151         outb((divisor >> 8) & 0xff, early_serial_base + DLH);
 152         outb(c & ~DLAB, early_serial_base + LCR);
 153 }
 154
 155 static struct console early_serial_console = {
 156         .name =         "earlyser",
 157         .write =        early_serial_write,
 158         .flags =        CON_PRINTBUFFER,
 159         .index =        -1,
 160 };
 161
 162 /* Console interface to a host file on AMD's SimNow! */
 163
 164 static int simnow_fd;
 165
 166 enum {
 167         MAGIC1 = 0xBACCD00A,
 168         MAGIC2 = 0xCA110000,
 169         XOPEN = 5,
 170         XWRITE = 4,
 171 };
 172
 173 static noinline long simnow(long cmd, long a, long b, long c)
 174 {
 175         long ret;
 176         asm volatile("cpuid" :
 177                      "=a" (ret) :
 178                      "b" (a), "c" (b), "d" (c), "0" (MAGIC1), "D" (cmd + MAGIC2));
 179         return ret;
 180 }
 181
 182 void __init simnow_init(char *str)
 183 {
 184         char *fn = "klog";
 185         if (*str == '=')
 186                 fn = ++str;
 187         /* error ignored */
 188         simnow_fd = simnow(XOPEN, (unsigned long)fn, O_WRONLY|O_APPEND|O_CREAT, 0644);
 189 }
 190
 191 static void simnow_write(struct console *con, const char *s, unsigned n)
 192 {
 193         simnow(XWRITE, simnow_fd, (unsigned long)s, n);
 194 }
 195
 196 static struct console simnow_console = {
 197         .name =         "simnow",
 198         .write =        simnow_write,
 199         .flags =        CON_PRINTBUFFER,
 200         .index =        -1,
 201 };
 202
 203 /* Direct interface for emergencies */
 204 struct console *early_console = &early_vga_console;
 205 static int early_console_initialized = 0;
 206
 207 void early_printk(const char *fmt, ...)
 208 {
 209         char buf[512];
 210         int n;
 211         va_list ap;
 212
 213         va_start(ap,fmt);
 214         n = vscnprintf(buf,512,fmt,ap);
 215         early_console->write(early_console,buf,n);
 216         va_end(ap);
 217 }
 218
 219 static int __initdata keep_early;
 220
 221 int __init setup_early_printk(char *opt)
 222 {
 223         char *space;
 224         char buf[256];
 225
 226         if (early_console_initialized)
 227                 return -1;
 228
 229         strlcpy(buf,opt,sizeof(buf));
 230         space = strchr(buf, ' ');
 231         if (space)
 232                 *space = 0;
 233
 234         if (strstr(buf,"keep"))
 235                 keep_early = 1;
 236
 237         if (!strncmp(buf, "serial", 6)) {
 238                 early_serial_init(buf + 6);
 239                 early_console = &early_serial_console;
 240         } else if (!strncmp(buf, "ttyS", 4)) {
 241                 early_serial_init(buf);
 242                 early_console = &early_serial_console;
 243         } else if (!strncmp(buf, "vga", 3)
 244                    && SCREEN_INFO.orig_video_isVGA == 1) {
 245                 max_xpos = SCREEN_INFO.orig_video_cols;
 246                 max_ypos = SCREEN_INFO.orig_video_lines;
 247                 early_console = &early_vga_console;
 248         } else if (!strncmp(buf, "simnow", 6)) {
 249                 simnow_init(buf + 6);
 250                 early_console = &simnow_console;
 251                 keep_early = 1;
 252         }
 253         early_console_initialized = 1;
 254         register_console(early_console);
 255         return 0;
 256 }
 257
 258 void __init disable_early_printk(void)
 259 {
 260         if (!early_console_initialized || !early_console)
 261                 return;
 262         if (!keep_early) {
 263                 printk("disabling early console\n");
 264                 unregister_console(early_console);
 265                 early_console_initialized = 0;
 266         } else {
 267                 printk("keeping early console\n");
 268         }
 269 }
 270
 271 __setup("earlyprintk=", setup_early_printk);