221 lines
5.2 KiB
C
221 lines
5.2 KiB
C
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#include <linux/console.h>
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/string.h>
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#include <asm/io.h>
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#include <asm/processor.h>
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/* Simple VGA output */
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#ifdef __i386__
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#define VGABASE (__ISA_IO_base + 0xb8000)
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#else
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#define VGABASE ((void __iomem *)0xffffffff800b8000UL)
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#endif
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#define MAX_YPOS 25
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#define MAX_XPOS 80
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static int current_ypos = 1, current_xpos = 0;
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static void early_vga_write(struct console *con, const char *str, unsigned n)
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{
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char c;
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int i, k, j;
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while ((c = *str++) != '\0' && n-- > 0) {
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if (current_ypos >= MAX_YPOS) {
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/* scroll 1 line up */
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for (k = 1, j = 0; k < MAX_YPOS; k++, j++) {
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for (i = 0; i < MAX_XPOS; i++) {
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writew(readw(VGABASE + 2*(MAX_XPOS*k + i)),
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VGABASE + 2*(MAX_XPOS*j + i));
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}
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}
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for (i = 0; i < MAX_XPOS; i++)
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writew(0x720, VGABASE + 2*(MAX_XPOS*j + i));
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current_ypos = MAX_YPOS-1;
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}
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if (c == '\n') {
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current_xpos = 0;
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current_ypos++;
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} else if (c != '\r') {
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writew(((0x7 << 8) | (unsigned short) c),
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VGABASE + 2*(MAX_XPOS*current_ypos +
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current_xpos++));
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if (current_xpos >= MAX_XPOS) {
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current_xpos = 0;
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current_ypos++;
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}
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}
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}
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}
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static struct console early_vga_console = {
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.name = "earlyvga",
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.write = early_vga_write,
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.flags = CON_PRINTBUFFER,
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.index = -1,
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};
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/* Serial functions loosely based on a similar package from Klaus P. Gerlicher */
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int early_serial_base = 0x3f8; /* ttyS0 */
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#define XMTRDY 0x20
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#define DLAB 0x80
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#define TXR 0 /* Transmit register (WRITE) */
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#define RXR 0 /* Receive register (READ) */
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#define IER 1 /* Interrupt Enable */
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#define IIR 2 /* Interrupt ID */
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#define FCR 2 /* FIFO control */
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#define LCR 3 /* Line control */
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#define MCR 4 /* Modem control */
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#define LSR 5 /* Line Status */
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#define MSR 6 /* Modem Status */
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#define DLL 0 /* Divisor Latch Low */
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#define DLH 1 /* Divisor latch High */
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static int early_serial_putc(unsigned char ch)
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{
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unsigned timeout = 0xffff;
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while ((inb(early_serial_base + LSR) & XMTRDY) == 0 && --timeout)
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cpu_relax();
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outb(ch, early_serial_base + TXR);
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return timeout ? 0 : -1;
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}
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static void early_serial_write(struct console *con, const char *s, unsigned n)
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{
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while (*s && n-- > 0) {
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early_serial_putc(*s);
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if (*s == '\n')
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early_serial_putc('\r');
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s++;
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}
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}
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#define DEFAULT_BAUD 9600
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static __init void early_serial_init(char *s)
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{
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unsigned char c;
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unsigned divisor;
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unsigned baud = DEFAULT_BAUD;
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char *e;
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if (*s == ',')
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++s;
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if (*s) {
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unsigned port;
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if (!strncmp(s,"0x",2)) {
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early_serial_base = simple_strtoul(s, &e, 16);
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} else {
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static int bases[] = { 0x3f8, 0x2f8 };
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if (!strncmp(s,"ttyS",4))
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s += 4;
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port = simple_strtoul(s, &e, 10);
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if (port > 1 || s == e)
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port = 0;
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early_serial_base = bases[port];
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}
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s += strcspn(s, ",");
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if (*s == ',')
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s++;
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}
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outb(0x3, early_serial_base + LCR); /* 8n1 */
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outb(0, early_serial_base + IER); /* no interrupt */
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outb(0, early_serial_base + FCR); /* no fifo */
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outb(0x3, early_serial_base + MCR); /* DTR + RTS */
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if (*s) {
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baud = simple_strtoul(s, &e, 0);
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if (baud == 0 || s == e)
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baud = DEFAULT_BAUD;
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}
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divisor = 115200 / baud;
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c = inb(early_serial_base + LCR);
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outb(c | DLAB, early_serial_base + LCR);
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outb(divisor & 0xff, early_serial_base + DLL);
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outb((divisor >> 8) & 0xff, early_serial_base + DLH);
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outb(c & ~DLAB, early_serial_base + LCR);
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}
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static struct console early_serial_console = {
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.name = "earlyser",
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.write = early_serial_write,
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.flags = CON_PRINTBUFFER,
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.index = -1,
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};
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/* Direct interface for emergencies */
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struct console *early_console = &early_vga_console;
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static int early_console_initialized = 0;
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void early_printk(const char *fmt, ...)
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{
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char buf[512];
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int n;
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va_list ap;
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va_start(ap,fmt);
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n = vscnprintf(buf,512,fmt,ap);
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early_console->write(early_console,buf,n);
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va_end(ap);
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}
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static int keep_early;
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int __init setup_early_printk(char *opt)
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{
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char *space;
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char buf[256];
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if (early_console_initialized)
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return -1;
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opt = strchr(opt, '=') + 1;
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strlcpy(buf,opt,sizeof(buf));
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space = strchr(buf, ' ');
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if (space)
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*space = 0;
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if (strstr(buf,"keep"))
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keep_early = 1;
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if (!strncmp(buf, "serial", 6)) {
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early_serial_init(buf + 6);
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early_console = &early_serial_console;
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} else if (!strncmp(buf, "ttyS", 4)) {
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early_serial_init(buf);
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early_console = &early_serial_console;
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} else if (!strncmp(buf, "vga", 3)) {
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early_console = &early_vga_console;
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}
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early_console_initialized = 1;
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register_console(early_console);
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return 0;
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}
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void __init disable_early_printk(void)
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{
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if (!early_console_initialized || !early_console)
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return;
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if (!keep_early) {
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printk("disabling early console\n");
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unregister_console(early_console);
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early_console_initialized = 0;
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} else {
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printk("keeping early console\n");
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}
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}
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__setup("earlyprintk=", setup_early_printk);
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