arch/x86/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 <linux/usb/ch9.h>
   7 #include <linux/pci_regs.h>
   8 #include <linux/pci_ids.h>
   9 #include <linux/errno.h>
  10 #include <asm/io.h>
  11 #include <asm/processor.h>
  12 #include <asm/fcntl.h>
  13 #include <asm/setup.h>
  14 #include <xen/hvc-console.h>
  15 #include <asm/pci-direct.h>
  16 #include <asm/fixmap.h>
  17 #include <asm/pgtable.h>
  18 #include <linux/usb/ehci_def.h>
  19
  20 /* Simple VGA output */
  21 #define VGABASE         (__ISA_IO_base + 0xb8000)
  22
  23 static int max_ypos = 25, max_xpos = 80;
  24 static int current_ypos = 25, current_xpos;
  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 #ifdef CONFIG_KGDB_KDB
  45                 if (c == '\b') {
  46                         if (current_xpos > 0)
  47                                 current_xpos--;
  48                 } else if (c == '\r') {
  49                         current_xpos = 0;
  50                 } else
  51 #endif
  52                 if (c == '\n') {
  53                         current_xpos = 0;
  54                         current_ypos++;
  55                 } else if (c != '\r')  {
  56                         writew(((0x7 << 8) | (unsigned short) c),
  57                                VGABASE + 2*(max_xpos*current_ypos +
  58                                                 current_xpos++));
  59                         if (current_xpos >= max_xpos) {
  60                                 current_xpos = 0;
  61                                 current_ypos++;
  62                         }
  63                 }
  64         }
  65 }
  66
  67 static struct console early_vga_console = {
  68         .name =         "earlyvga",
  69         .write =        early_vga_write,
  70         .flags =        CON_PRINTBUFFER,
  71         .index =        -1,
  72 };
  73
  74 /* Serial functions loosely based on a similar package from Klaus P. Gerlicher */
  75
  76 static int early_serial_base = 0x3f8;  /* ttyS0 */
  77
  78 #define XMTRDY          0x20
  79
  80 #define DLAB            0x80
  81
  82 #define TXR             0       /*  Transmit register (WRITE) */
  83 #define RXR             0       /*  Receive register  (READ)  */
  84 #define IER             1       /*  Interrupt Enable          */
  85 #define IIR             2       /*  Interrupt ID              */
  86 #define FCR             2       /*  FIFO control              */
  87 #define LCR             3       /*  Line control              */
  88 #define MCR             4       /*  Modem control             */
  89 #define LSR             5       /*  Line Status               */
  90 #define MSR             6       /*  Modem Status              */
  91 #define DLL             0       /*  Divisor Latch Low         */
  92 #define DLH             1       /*  Divisor latch High        */
  93
  94 static int early_serial_putc(unsigned char ch)
  95 {
  96         unsigned timeout = 0xffff;
  97
  98         while ((inb(early_serial_base + LSR) & XMTRDY) == 0 && --timeout)
  99                 cpu_relax();
 100         outb(ch, early_serial_base + TXR);
 101         return timeout ? 0 : -1;
 102 }
 103
 104 static void early_serial_write(struct console *con, const char *s, unsigned n)
 105 {
 106         while (*s && n-- > 0) {
 107                 if (*s == '\n')
 108                         early_serial_putc('\r');
 109                 early_serial_putc(*s);
 110                 s++;
 111         }
 112 }
 113
 114 #define DEFAULT_BAUD 9600
 115
 116 static __init void early_serial_init(char *s)
 117 {
 118         unsigned char c;
 119         unsigned divisor;
 120         unsigned baud = DEFAULT_BAUD;
 121         char *e;
 122
 123         if (*s == ',')
 124                 ++s;
 125
 126         if (*s) {
 127                 unsigned port;
 128                 if (!strncmp(s, "0x", 2)) {
 129                         early_serial_base = simple_strtoul(s, &e, 16);
 130                 } else {
 131                         static const int __initconst bases[] = { 0x3f8, 0x2f8 };
 132
 133                         if (!strncmp(s, "ttyS", 4))
 134                                 s += 4;
 135                         port = simple_strtoul(s, &e, 10);
 136                         if (port > 1 || s == e)
 137                                 port = 0;
 138                         early_serial_base = bases[port];
 139                 }
 140                 s += strcspn(s, ",");
 141                 if (*s == ',')
 142                         s++;
 143         }
 144
 145         outb(0x3, early_serial_base + LCR);     /* 8n1 */
 146         outb(0, early_serial_base + IER);       /* no interrupt */
 147         outb(0, early_serial_base + FCR);       /* no fifo */
 148         outb(0x3, early_serial_base + MCR);     /* DTR + RTS */
 149
 150         if (*s) {
 151                 baud = simple_strtoul(s, &e, 0);
 152                 if (baud == 0 || s == e)
 153                         baud = DEFAULT_BAUD;
 154         }
 155
 156         divisor = 115200 / baud;
 157         c = inb(early_serial_base + LCR);
 158         outb(c | DLAB, early_serial_base + LCR);
 159         outb(divisor & 0xff, early_serial_base + DLL);
 160         outb((divisor >> 8) & 0xff, early_serial_base + DLH);
 161         outb(c & ~DLAB, early_serial_base + LCR);
 162 }
 163
 164 static struct console early_serial_console = {
 165         .name =         "earlyser",
 166         .write =        early_serial_write,
 167         .flags =        CON_PRINTBUFFER,
 168         .index =        -1,
 169 };
 170
 171 /* Direct interface for emergencies */
 172 static struct console *early_console = &early_vga_console;
 173 static int __initdata early_console_initialized;
 174
 175 asmlinkage void early_printk(const char *fmt, ...)
 176 {
 177         char buf[512];
 178         int n;
 179         va_list ap;
 180
 181         va_start(ap, fmt);
 182         n = vscnprintf(buf, sizeof(buf), fmt, ap);
 183         early_console->write(early_console, buf, n);
 184         va_end(ap);
 185 }
 186
 187 static inline void early_console_register(struct console *con, int keep_early)
 188 {
 189         if (early_console->index != -1) {
 190                 printk(KERN_CRIT "ERROR: earlyprintk= %s already used\n",
 191                        con->name);
 192                 return;
 193         }
 194         early_console = con;
 195         if (keep_early)
 196                 early_console->flags &= ~CON_BOOT;
 197         else
 198                 early_console->flags |= CON_BOOT;
 199         register_console(early_console);
 200 }
 201
 202 static int __init setup_early_printk(char *buf)
 203 {
 204         int keep;
 205
 206         if (!buf)
 207                 return 0;
 208
 209         if (early_console_initialized)
 210                 return 0;
 211         early_console_initialized = 1;
 212
 213         keep = (strstr(buf, "keep") != NULL);
 214
 215         while (*buf != '\0') {
 216                 if (!strncmp(buf, "serial", 6)) {
 217                         buf += 6;
 218                         early_serial_init(buf);
 219                         early_console_register(&early_serial_console, keep);
 220                         if (!strncmp(buf, ",ttyS", 5))
 221                                 buf += 5;
 222                 }
 223                 if (!strncmp(buf, "ttyS", 4)) {
 224                         early_serial_init(buf + 4);
 225                         early_console_register(&early_serial_console, keep);
 226                 }
 227                 if (!strncmp(buf, "vga", 3) &&
 228                     boot_params.screen_info.orig_video_isVGA == 1) {
 229                         max_xpos = boot_params.screen_info.orig_video_cols;
 230                         max_ypos = boot_params.screen_info.orig_video_lines;
 231                         current_ypos = boot_params.screen_info.orig_y;
 232                         early_console_register(&early_vga_console, keep);
 233                 }
 234 #ifdef CONFIG_EARLY_PRINTK_DBGP
 235                 if (!strncmp(buf, "dbgp", 4) && !early_dbgp_init(buf + 4))
 236                         early_console_register(&early_dbgp_console, keep);
 237 #endif
 238 #ifdef CONFIG_HVC_XEN
 239                 if (!strncmp(buf, "xen", 3))
 240                         early_console_register(&xenboot_console, keep);
 241 #endif
 242                 buf++;
 243         }
 244         return 0;
 245 }
 246
 247 early_param("earlyprintk", setup_early_printk);