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                             unsigned int loglevel)
  29 {
  30         char c;
  31         int  i, k, j;
  32
  33         while ((c = *str++) != '\0' && n-- > 0) {
  34                 if (current_ypos >= max_ypos) {
  35                         /* scroll 1 line up */
  36                         for (k = 1, j = 0; k < max_ypos; k++, j++) {
  37                                 for (i = 0; i < max_xpos; i++) {
  38                                         writew(readw(VGABASE+2*(max_xpos*k+i)),
  39                                                VGABASE + 2*(max_xpos*j + i));
  40                                 }
  41                         }
  42                         for (i = 0; i < max_xpos; i++)
  43                                 writew(0x720, VGABASE + 2*(max_xpos*j + i));
  44                         current_ypos = max_ypos-1;
  45                 }
  46 #ifdef CONFIG_KGDB_KDB
  47                 if (c == '\b') {
  48                         if (current_xpos > 0)
  49                                 current_xpos--;
  50                 } else if (c == '\r') {
  51                         current_xpos = 0;
  52                 } else
  53 #endif
  54                 if (c == '\n') {
  55                         current_xpos = 0;
  56                         current_ypos++;
  57                 } else if (c != '\r')  {
  58                         writew(((0x7 << 8) | (unsigned short) c),
  59                                VGABASE + 2*(max_xpos*current_ypos +
  60                                                 current_xpos++));
  61                         if (current_xpos >= max_xpos) {
  62                                 current_xpos = 0;
  63                                 current_ypos++;
  64                         }
  65                 }
  66         }
  67 }
  68
  69 static struct console early_vga_console = {
  70         .name =         "earlyvga",
  71         .write =        early_vga_write,
  72         .flags =        CON_PRINTBUFFER,
  73         .index =        -1,
  74 };
  75
  76 /* Serial functions loosely based on a similar package from Klaus P. Gerlicher */
  77
  78 static int early_serial_base = 0x3f8;  /* ttyS0 */
  79
  80 #define XMTRDY          0x20
  81
  82 #define DLAB            0x80
  83
  84 #define TXR             0       /*  Transmit register (WRITE) */
  85 #define RXR             0       /*  Receive register  (READ)  */
  86 #define IER             1       /*  Interrupt Enable          */
  87 #define IIR             2       /*  Interrupt ID              */
  88 #define FCR             2       /*  FIFO control              */
  89 #define LCR             3       /*  Line control              */
  90 #define MCR             4       /*  Modem control             */
  91 #define LSR             5       /*  Line Status               */
  92 #define MSR             6       /*  Modem Status              */
  93 #define DLL             0       /*  Divisor Latch Low         */
  94 #define DLH             1       /*  Divisor latch High        */
  95
  96 static int early_serial_putc(unsigned char ch)
  97 {
  98         unsigned timeout = 0xffff;
  99
 100         while ((inb(early_serial_base + LSR) & XMTRDY) == 0 && --timeout)
 101                 cpu_relax();
 102         outb(ch, early_serial_base + TXR);
 103         return timeout ? 0 : -1;
 104 }
 105
 106 static void early_serial_write(struct console *con, const char *s, unsigned n,
 107                                unsigned int loglevel)
 108 {
 109         while (*s && n-- > 0) {
 110                 if (*s == '\n')
 111                         early_serial_putc('\r');
 112                 early_serial_putc(*s);
 113                 s++;
 114         }
 115 }
 116
 117 #define DEFAULT_BAUD 9600
 118
 119 static __init void early_serial_init(char *s)
 120 {
 121         unsigned char c;
 122         unsigned divisor;
 123         unsigned baud = DEFAULT_BAUD;
 124         char *e;
 125
 126         if (*s == ',')
 127                 ++s;
 128
 129         if (*s) {
 130                 unsigned port;
 131                 if (!strncmp(s, "0x", 2)) {
 132                         early_serial_base = simple_strtoul(s, &e, 16);
 133                 } else {
 134                         static const int __initconst bases[] = { 0x3f8, 0x2f8 };
 135
 136                         if (!strncmp(s, "ttyS", 4))
 137                                 s += 4;
 138                         port = simple_strtoul(s, &e, 10);
 139                         if (port > 1 || s == e)
 140                                 port = 0;
 141                         early_serial_base = bases[port];
 142                 }
 143                 s += strcspn(s, ",");
 144                 if (*s == ',')
 145                         s++;
 146         }
 147
 148         outb(0x3, early_serial_base + LCR);     /* 8n1 */
 149         outb(0, early_serial_base + IER);       /* no interrupt */
 150         outb(0, early_serial_base + FCR);       /* no fifo */
 151         outb(0x3, early_serial_base + MCR);     /* DTR + RTS */
 152
 153         if (*s) {
 154                 baud = simple_strtoul(s, &e, 0);
 155                 if (baud == 0 || s == e)
 156                         baud = DEFAULT_BAUD;
 157         }
 158
 159         divisor = 115200 / baud;
 160         c = inb(early_serial_base + LCR);
 161         outb(c | DLAB, early_serial_base + LCR);
 162         outb(divisor & 0xff, early_serial_base + DLL);
 163         outb((divisor >> 8) & 0xff, early_serial_base + DLH);
 164         outb(c & ~DLAB, early_serial_base + LCR);
 165 }
 166
 167 static struct console early_serial_console = {
 168         .name =         "earlyser",
 169         .write =        early_serial_write,
 170         .flags =        CON_PRINTBUFFER,
 171         .index =        -1,
 172 };
 173
 174 /* Direct interface for emergencies */
 175 static struct console *early_console = &early_vga_console;
 176 static int __initdata early_console_initialized;
 177
 178 asmlinkage void early_printk(const char *fmt, ...)
 179 {
 180         char buf[512];
 181         int n;
 182         va_list ap;
 183
 184         va_start(ap, fmt);
 185         n = vscnprintf(buf, sizeof(buf), fmt, ap);
 186         early_console->write(early_console, buf, n, 0);
 187         va_end(ap);
 188 }
 189
 190 static inline void early_console_register(struct console *con, int keep_early)
 191 {
 192         if (early_console->index != -1) {
 193                 printk(KERN_CRIT "ERROR: earlyprintk= %s already used\n",
 194                        con->name);
 195                 return;
 196         }
 197         early_console = con;
 198         if (keep_early)
 199                 early_console->flags &= ~CON_BOOT;
 200         else
 201                 early_console->flags |= CON_BOOT;
 202         register_console(early_console);
 203 }
 204
 205 static int __init setup_early_printk(char *buf)
 206 {
 207         int keep;
 208
 209         if (!buf)
 210                 return 0;
 211
 212         if (early_console_initialized)
 213                 return 0;
 214         early_console_initialized = 1;
 215
 216         keep = (strstr(buf, "keep") != NULL);
 217
 218         while (*buf != '\0') {
 219                 if (!strncmp(buf, "serial", 6)) {
 220                         buf += 6;
 221                         early_serial_init(buf);
 222                         early_console_register(&early_serial_console, keep);
 223                         if (!strncmp(buf, ",ttyS", 5))
 224                                 buf += 5;
 225                 }
 226                 if (!strncmp(buf, "ttyS", 4)) {
 227                         early_serial_init(buf + 4);
 228                         early_console_register(&early_serial_console, keep);
 229                 }
 230                 if (!strncmp(buf, "vga", 3) &&
 231                     boot_params.screen_info.orig_video_isVGA == 1) {
 232                         max_xpos = boot_params.screen_info.orig_video_cols;
 233                         max_ypos = boot_params.screen_info.orig_video_lines;
 234                         current_ypos = boot_params.screen_info.orig_y;
 235                         early_console_register(&early_vga_console, keep);
 236                 }
 237 #ifdef CONFIG_EARLY_PRINTK_DBGP
 238                 if (!strncmp(buf, "dbgp", 4) && !early_dbgp_init(buf + 4))
 239                         early_console_register(&early_dbgp_console, keep);
 240 #endif
 241 #ifdef CONFIG_HVC_XEN
 242                 if (!strncmp(buf, "xen", 3))
 243                         early_console_register(&xenboot_console, keep);
 244 #endif
 245 #ifdef CONFIG_EARLY_PRINTK_INTEL_MID
 246                 if (!strncmp(buf, "mrst", 4)) {
 247                         mrst_early_console_init();
 248                         early_console_register(&early_mrst_console, keep);
 249                 }
 250
 251                 if (!strncmp(buf, "hsu", 3)) {
 252                         hsu_early_console_init(buf + 3);
 253                         early_console_register(&early_hsu_console, keep);
 254                 }
 255 #endif
 256                 buf++;
 257         }
 258         return 0;
 259 }
 260
 261 early_param("earlyprintk", setup_early_printk);