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/mrst.h>
  18 #include <asm/pgtable.h>
  19 #include <linux/usb/ehci_def.h>
  20
  21 /* Simple VGA output */
  22 #define VGABASE         (__ISA_IO_base + 0xb8000)
  23
  24 static int max_ypos = 25, max_xpos = 80;
  25 static int current_ypos = 25, current_xpos;
  26
  27 static void early_vga_write(struct console *con, const char *str, unsigned n)
  28 {
  29         char c;
  30         int  i, k, j;
  31
  32         while ((c = *str++) != '\0' && n-- > 0) {
  33                 if (current_ypos >= max_ypos) {
  34                         /* scroll 1 line up */
  35                         for (k = 1, j = 0; k < max_ypos; k++, j++) {
  36                                 for (i = 0; i < max_xpos; i++) {
  37                                         writew(readw(VGABASE+2*(max_xpos*k+i)),
  38                                                VGABASE + 2*(max_xpos*j + i));
  39                                 }
  40                         }
  41                         for (i = 0; i < max_xpos; i++)
  42                                 writew(0x720, VGABASE + 2*(max_xpos*j + i));
  43                         current_ypos = max_ypos-1;
  44                 }
  45 #ifdef CONFIG_KGDB_KDB
  46                 if (c == '\b') {
  47                         if (current_xpos > 0)
  48                                 current_xpos--;
  49                 } else if (c == '\r') {
  50                         current_xpos = 0;
  51                 } else
  52 #endif
  53                 if (c == '\n') {
  54                         current_xpos = 0;
  55                         current_ypos++;
  56                 } else if (c != '\r')  {
  57                         writew(((0x7 << 8) | (unsigned short) c),
  58                                VGABASE + 2*(max_xpos*current_ypos +
  59                                                 current_xpos++));
  60                         if (current_xpos >= max_xpos) {
  61                                 current_xpos = 0;
  62                                 current_ypos++;
  63                         }
  64                 }
  65         }
  66 }
  67
  68 static struct console early_vga_console = {
  69         .name =         "earlyvga",
  70         .write =        early_vga_write,
  71         .flags =        CON_PRINTBUFFER,
  72         .index =        -1,
  73 };
  74
  75 /* Serial functions loosely based on a similar package from Klaus P. Gerlicher */
  76
  77 static int early_serial_base = 0x3f8;  /* ttyS0 */
  78
  79 #define XMTRDY          0x20
  80
  81 #define DLAB            0x80
  82
  83 #define TXR             0       /*  Transmit register (WRITE) */
  84 #define RXR             0       /*  Receive register  (READ)  */
  85 #define IER             1       /*  Interrupt Enable          */
  86 #define IIR             2       /*  Interrupt ID              */
  87 #define FCR             2       /*  FIFO control              */
  88 #define LCR             3       /*  Line control              */
  89 #define MCR             4       /*  Modem control             */
  90 #define LSR             5       /*  Line Status               */
  91 #define MSR             6       /*  Modem Status              */
  92 #define DLL             0       /*  Divisor Latch Low         */
  93 #define DLH             1       /*  Divisor latch High        */
  94
  95 static int early_serial_putc(unsigned char ch)
  96 {
  97         unsigned timeout = 0xffff;
  98
  99         while ((inb(early_serial_base + LSR) & XMTRDY) == 0 && --timeout)
 100                 cpu_relax();
 101         outb(ch, early_serial_base + TXR);
 102         return timeout ? 0 : -1;
 103 }
 104
 105 static void early_serial_write(struct console *con, const char *s, unsigned n)
 106 {
 107         while (*s && n-- > 0) {
 108                 if (*s == '\n')
 109                         early_serial_putc('\r');
 110                 early_serial_putc(*s);
 111                 s++;
 112         }
 113 }
 114
 115 #define DEFAULT_BAUD 9600
 116
 117 static __init void early_serial_init(char *s)
 118 {
 119         unsigned char c;
 120         unsigned divisor;
 121         unsigned baud = DEFAULT_BAUD;
 122         char *e;
 123
 124         if (*s == ',')
 125                 ++s;
 126
 127         if (*s) {
 128                 unsigned port;
 129                 if (!strncmp(s, "0x", 2)) {
 130                         early_serial_base = simple_strtoul(s, &e, 16);
 131                 } else {
 132                         static const int __initconst bases[] = { 0x3f8, 0x2f8 };
 133
 134                         if (!strncmp(s, "ttyS", 4))
 135                                 s += 4;
 136                         port = simple_strtoul(s, &e, 10);
 137                         if (port > 1 || s == e)
 138                                 port = 0;
 139                         early_serial_base = bases[port];
 140                 }
 141                 s += strcspn(s, ",");
 142                 if (*s == ',')
 143                         s++;
 144         }
 145
 146         outb(0x3, early_serial_base + LCR);     /* 8n1 */
 147         outb(0, early_serial_base + IER);       /* no interrupt */
 148         outb(0, early_serial_base + FCR);       /* no fifo */
 149         outb(0x3, early_serial_base + MCR);     /* DTR + RTS */
 150
 151         if (*s) {
 152                 baud = simple_strtoul(s, &e, 0);
 153                 if (baud == 0 || s == e)
 154                         baud = DEFAULT_BAUD;
 155         }
 156
 157         divisor = 115200 / baud;
 158         c = inb(early_serial_base + LCR);
 159         outb(c | DLAB, early_serial_base + LCR);
 160         outb(divisor & 0xff, early_serial_base + DLL);
 161         outb((divisor >> 8) & 0xff, early_serial_base + DLH);
 162         outb(c & ~DLAB, early_serial_base + LCR);
 163 }
 164
 165 static struct console early_serial_console = {
 166         .name =         "earlyser",
 167         .write =        early_serial_write,
 168         .flags =        CON_PRINTBUFFER,
 169         .index =        -1,
 170 };
 171
 172 /* Direct interface for emergencies */
 173 static struct console *early_console = &early_vga_console;
 174 static int __initdata early_console_initialized;
 175
 176 asmlinkage void early_printk(const char *fmt, ...)
 177 {
 178         char buf[512];
 179         int n;
 180         va_list ap;
 181
 182         va_start(ap, fmt);
 183         n = vscnprintf(buf, sizeof(buf), fmt, ap);
 184         early_console->write(early_console, buf, n);
 185         va_end(ap);
 186 }
 187
 188 static inline void early_console_register(struct console *con, int keep_early)
 189 {
 190         if (early_console->index != -1) {
 191                 printk(KERN_CRIT "ERROR: earlyprintk= %s already used\n",
 192                        con->name);
 193                 return;
 194         }
 195         early_console = con;
 196         if (keep_early)
 197                 early_console->flags &= ~CON_BOOT;
 198         else
 199                 early_console->flags |= CON_BOOT;
 200         register_console(early_console);
 201 }
 202
 203 static int __init setup_early_printk(char *buf)
 204 {
 205         int keep;
 206
 207         if (!buf)
 208                 return 0;
 209
 210         if (early_console_initialized)
 211                 return 0;
 212         early_console_initialized = 1;
 213
 214         keep = (strstr(buf, "keep") != NULL);
 215
 216         while (*buf != '\0') {
 217                 if (!strncmp(buf, "serial", 6)) {
 218                         buf += 6;
 219                         early_serial_init(buf);
 220                         early_console_register(&early_serial_console, keep);
 221                         if (!strncmp(buf, ",ttyS", 5))
 222                                 buf += 5;
 223                 }
 224                 if (!strncmp(buf, "ttyS", 4)) {
 225                         early_serial_init(buf + 4);
 226                         early_console_register(&early_serial_console, keep);
 227                 }
 228                 if (!strncmp(buf, "vga", 3) &&
 229                     boot_params.screen_info.orig_video_isVGA == 1) {
 230                         max_xpos = boot_params.screen_info.orig_video_cols;
 231                         max_ypos = boot_params.screen_info.orig_video_lines;
 232                         current_ypos = boot_params.screen_info.orig_y;
 233                         early_console_register(&early_vga_console, keep);
 234                 }
 235 #ifdef CONFIG_EARLY_PRINTK_DBGP
 236                 if (!strncmp(buf, "dbgp", 4) && !early_dbgp_init(buf + 4))
 237                         early_console_register(&early_dbgp_console, keep);
 238 #endif
 239 #ifdef CONFIG_HVC_XEN
 240                 if (!strncmp(buf, "xen", 3))
 241                         early_console_register(&xenboot_console, keep);
 242 #endif
 243 #ifdef CONFIG_EARLY_PRINTK_INTEL_MID
 244                 if (!strncmp(buf, "mrst", 4)) {
 245                         mrst_early_console_init();
 246                         early_console_register(&early_mrst_console, keep);
 247                 }
 248
 249                 if (!strncmp(buf, "hsu", 3)) {
 250                         hsu_early_console_init(buf + 3);
 251                         early_console_register(&early_hsu_console, keep);
 252                 }
 253 #endif
 254                 buf++;
 255         }
 256         return 0;
 257 }
 258
 259 early_param("earlyprintk", setup_early_printk);