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 #include <xen/hvc-console.h>
  10
  11 /* Simple VGA output */
  12
  13 #ifdef __i386__
  14 #include <asm/setup.h>
  15 #else
  16 #include <asm/bootsetup.h>
  17 #endif
  18 #define VGABASE         (__ISA_IO_base + 0xb8000)
  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                 if (*s == '\n')
  96                         early_serial_putc('\r');
  97                 early_serial_putc(*s);
  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 static 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 (strstr(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 #ifdef CONFIG_HVC_XEN
 247         } else if (!strncmp(buf, "xen", 3)) {
 248                 early_console = &xenboot_console;
 249 #endif
 250         }
 251
 252         if (keep_early)
 253                 early_console->flags &= ~CON_BOOT;
 254         else
 255                 early_console->flags |= CON_BOOT;
 256         register_console(early_console);
 257         return 0;
 258 }
 259 early_param("earlyprintk", setup_early_printk);