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                 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
  90         while ((inb(early_serial_base + LSR) & XMTRDY) == 0 && --timeout)
  91                 cpu_relax();
  92         outb(ch, early_serial_base + TXR);
  93         return timeout ? 0 : -1;
  94 }
  95
  96 static void early_serial_write(struct console *con, const char *s, unsigned n)
  97 {
  98         while (*s && n-- > 0) {
  99                 if (*s == '\n')
 100                         early_serial_putc('\r');
 101                 early_serial_putc(*s);
 102                 s++;
 103         }
 104 }
 105
 106 #define DEFAULT_BAUD 9600
 107
 108 static __init void early_serial_init(char *s)
 109 {
 110         unsigned char c;
 111         unsigned divisor;
 112         unsigned baud = DEFAULT_BAUD;
 113         char *e;
 114
 115         if (*s == ',')
 116                 ++s;
 117
 118         if (*s) {
 119                 unsigned port;
 120                 if (!strncmp(s, "0x", 2)) {
 121                         early_serial_base = simple_strtoul(s, &e, 16);
 122                 } else {
 123                         static const int __initconst bases[] = { 0x3f8, 0x2f8 };
 124
 125                         if (!strncmp(s, "ttyS", 4))
 126                                 s += 4;
 127                         port = simple_strtoul(s, &e, 10);
 128                         if (port > 1 || s == e)
 129                                 port = 0;
 130                         early_serial_base = bases[port];
 131                 }
 132                 s += strcspn(s, ",");
 133                 if (*s == ',')
 134                         s++;
 135         }
 136
 137         outb(0x3, early_serial_base + LCR);     /* 8n1 */
 138         outb(0, early_serial_base + IER);       /* no interrupt */
 139         outb(0, early_serial_base + FCR);       /* no fifo */
 140         outb(0x3, early_serial_base + MCR);     /* DTR + RTS */
 141
 142         if (*s) {
 143                 baud = simple_strtoul(s, &e, 0);
 144                 if (baud == 0 || s == e)
 145                         baud = DEFAULT_BAUD;
 146         }
 147
 148         divisor = 115200 / baud;
 149         c = inb(early_serial_base + LCR);
 150         outb(c | DLAB, early_serial_base + LCR);
 151         outb(divisor & 0xff, early_serial_base + DLL);
 152         outb((divisor >> 8) & 0xff, early_serial_base + DLH);
 153         outb(c & ~DLAB, early_serial_base + LCR);
 154 }
 155
 156 static struct console early_serial_console = {
 157         .name =         "earlyser",
 158         .write =        early_serial_write,
 159         .flags =        CON_PRINTBUFFER,
 160         .index =        -1,
 161 };
 162
 163 /* Direct interface for emergencies */
 164 static struct console *early_console = &early_vga_console;
 165 static int __initdata early_console_initialized;
 166
 167 asmlinkage void early_printk(const char *fmt, ...)
 168 {
 169         char buf[512];
 170         int n;
 171         va_list ap;
 172
 173         va_start(ap, fmt);
 174         n = vscnprintf(buf, sizeof(buf), fmt, ap);
 175         early_console->write(early_console, buf, n);
 176         va_end(ap);
 177 }
 178
 179 static inline void early_console_register(struct console *con, int keep_early)
 180 {
 181         if (early_console->index != -1) {
 182                 printk(KERN_CRIT "ERROR: earlyprintk= %s already used\n",
 183                        con->name);
 184                 return;
 185         }
 186         early_console = con;
 187         if (keep_early)
 188                 early_console->flags &= ~CON_BOOT;
 189         else
 190                 early_console->flags |= CON_BOOT;
 191         register_console(early_console);
 192 }
 193
 194 static int __init setup_early_printk(char *buf)
 195 {
 196         int keep;
 197
 198         if (!buf)
 199                 return 0;
 200
 201         if (early_console_initialized)
 202                 return 0;
 203         early_console_initialized = 1;
 204
 205         keep = (strstr(buf, "keep") != NULL);
 206
 207         while (*buf != '\0') {
 208                 if (!strncmp(buf, "serial", 6)) {
 209                         buf += 6;
 210                         early_serial_init(buf);
 211                         early_console_register(&early_serial_console, keep);
 212                         if (!strncmp(buf, ",ttyS", 5))
 213                                 buf += 5;
 214                 }
 215                 if (!strncmp(buf, "ttyS", 4)) {
 216                         early_serial_init(buf + 4);
 217                         early_console_register(&early_serial_console, keep);
 218                 }
 219                 if (!strncmp(buf, "vga", 3) &&
 220                     boot_params.screen_info.orig_video_isVGA == 1) {
 221                         max_xpos = boot_params.screen_info.orig_video_cols;
 222                         max_ypos = boot_params.screen_info.orig_video_lines;
 223                         current_ypos = boot_params.screen_info.orig_y;
 224                         early_console_register(&early_vga_console, keep);
 225                 }
 226 #ifdef CONFIG_EARLY_PRINTK_DBGP
 227                 if (!strncmp(buf, "dbgp", 4) && !early_dbgp_init(buf + 4))
 228                         early_console_register(&early_dbgp_console, keep);
 229 #endif
 230 #ifdef CONFIG_HVC_XEN
 231                 if (!strncmp(buf, "xen", 3))
 232                         early_console_register(&xenboot_console, keep);
 233 #endif
 234                 buf++;
 235         }
 236         return 0;
 237 }
 238
 239 early_param("earlyprintk", setup_early_printk);