arch/xen/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 <asm/io.h>
   6 #include <asm/processor.h>
   7
   8 /* Simple VGA output */
   9
  10 #ifdef __i386__
  11 #define VGABASE         (__ISA_IO_base + 0xb8000)
  12 #else
  13 #define VGABASE         ((void __iomem *)0xffffffff800b8000UL)
  14 #endif
  15
  16 #define MAX_YPOS        25
  17 #define MAX_XPOS        80
  18
  19 #if 0
  20 static int current_ypos = 1, 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 #endif
  62
  63 /* Serial functions loosely based on a similar package from Klaus P. Gerlicher */
  64
  65 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 #if 0
  84 static int early_serial_putc(unsigned char ch)
  85 {
  86         unsigned timeout = 0xffff;
  87         while ((inb(early_serial_base + LSR) & XMTRDY) == 0 && --timeout)
  88                 cpu_relax();
  89         outb(ch, early_serial_base + TXR);
  90         return timeout ? 0 : -1;
  91 }
  92
  93 static void early_serial_write(struct console *con, const char *s, unsigned n)
  94 {
  95         while (*s && n-- > 0) {
  96                 early_serial_putc(*s);
  97                 if (*s == '\n')
  98                         early_serial_putc('\r');
  99                 s++;
 100         }
 101 }
 102 #endif
 103
 104 #define DEFAULT_BAUD 9600
 105
 106 #if 0
 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 #endif
 162
 163 static void xen_console_write(struct console *con, const char *s, unsigned n)
 164 {
 165         HYPERVISOR_console_io(CONSOLEIO_write, n, (char *) s);
 166 }
 167
 168 static struct console xen_console = {
 169         .name =         "xen",
 170         .write =        xen_console_write,
 171         .flags =        CON_PRINTBUFFER,
 172         .index =        -1,
 173 };
 174
 175 /* Direct interface for emergencies */
 176 struct console *early_console = &xen_console;
 177 /* struct console *early_console = &early_vga_console; */
 178 static int early_console_initialized = 0;
 179
 180 void early_printk(const char *fmt, ...)
 181 {
 182         char buf[512];
 183         int n;
 184         va_list ap;
 185
 186         va_start(ap,fmt);
 187         n = vscnprintf(buf,512,fmt,ap);
 188         early_console->write(early_console,buf,n);
 189         va_end(ap);
 190 }
 191
 192 static int keep_early;
 193
 194 int __init setup_early_printk(char *opt)
 195 {
 196
 197         early_console = &xen_console;
 198 #if 0
 199         if (early_console_initialized)
 200                 return -1;
 201
 202         opt = strchr(opt, '=') + 1;
 203
 204         strlcpy(buf,opt,sizeof(buf));
 205         space = strchr(buf, ' ');
 206         if (space)
 207                 *space = 0;
 208
 209         if (strstr(buf,"keep"))
 210                 keep_early = 1;
 211
 212         if (!strncmp(buf, "serial", 6)) {
 213                 early_serial_init(buf + 6);
 214                 early_console = &early_serial_console;
 215         } else if (!strncmp(buf, "ttyS", 4)) {
 216                 early_serial_init(buf);
 217                 early_console = &early_serial_console;
 218         } else if (!strncmp(buf, "vga", 3)) {
 219                 early_console = &early_vga_console;
 220         }
 221 #endif
 222         early_console_initialized = 1;
 223         register_console(early_console);
 224         return 0;
 225 }
 226
 227 void __init disable_early_printk(void)
 228 {
 229         if (!early_console_initialized || !early_console)
 230                 return;
 231         if (!keep_early) {
 232                 printk("disabling early console\n");
 233                 unregister_console(early_console);
 234                 early_console_initialized = 0;
 235         } else {
 236                 printk("keeping early console\n");
 237         }
 238 }
 239
 240 __setup("earlyprintk=", setup_early_printk);