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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-changelog] early_printk.c:
ChangeSet 1.1860.1.1, 2005/05/16 10:49:20+01:00, cl349@xxxxxxxxxxxxxxxxxxxx
early_printk.c:
Add support for CONFIG_EARLY_PRINTK over Xen's serial console.
new file
Signed-off-by: Christian Limpach <Christian.Limpach@xxxxxxxxxxxx>
early_printk.c | 242 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 242 insertions(+)
diff -Nru a/linux-2.6.11-xen-sparse/arch/xen/x86_64/kernel/early_printk.c
b/linux-2.6.11-xen-sparse/arch/xen/x86_64/kernel/early_printk.c
--- /dev/null Wed Dec 31 16:00:00 196900
+++ b/linux-2.6.11-xen-sparse/arch/xen/x86_64/kernel/early_printk.c
2005-05-16 13:06:18 -04:00
@@ -0,0 +1,242 @@
+#include <linux/config.h>
+#include <linux/console.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/string.h>
+#include <asm/io.h>
+#include <asm/processor.h>
+
+/* Simple VGA output */
+
+#ifdef __i386__
+#define VGABASE (__ISA_IO_base + 0xb8000)
+#else
+#define VGABASE ((void __iomem *)0xffffffff800b8000UL)
+#endif
+
+#define MAX_YPOS 25
+#define MAX_XPOS 80
+
+static int current_ypos = 1, current_xpos = 0;
+
+static void early_vga_write(struct console *con, const char *str, unsigned n)
+{
+ char c;
+ int i, k, j;
+
+ while ((c = *str++) != '\0' && n-- > 0) {
+ if (current_ypos >= MAX_YPOS) {
+ /* scroll 1 line up */
+ for (k = 1, j = 0; k < MAX_YPOS; k++, j++) {
+ for (i = 0; i < MAX_XPOS; i++) {
+ writew(readw(VGABASE + 2*(MAX_XPOS*k +
i)),
+ VGABASE + 2*(MAX_XPOS*j + i));
+ }
+ }
+ for (i = 0; i < MAX_XPOS; i++)
+ writew(0x720, VGABASE + 2*(MAX_XPOS*j + i));
+ current_ypos = MAX_YPOS-1;
+ }
+ if (c == '\n') {
+ current_xpos = 0;
+ current_ypos++;
+ } else if (c != '\r') {
+ writew(((0x7 << 8) | (unsigned short) c),
+ VGABASE + 2*(MAX_XPOS*current_ypos +
+ current_xpos++));
+ if (current_xpos >= MAX_XPOS) {
+ current_xpos = 0;
+ current_ypos++;
+ }
+ }
+ }
+}
+
+static struct console early_vga_console = {
+ .name = "earlyvga",
+ .write = early_vga_write,
+ .flags = CON_PRINTBUFFER,
+ .index = -1,
+};
+
+#ifndef CONFIG_XEN
+/* Serial functions loosely based on a similar package from Klaus P. Gerlicher
*/
+
+int early_serial_base = 0x3f8; /* ttyS0 */
+
+#define XMTRDY 0x20
+
+#define DLAB 0x80
+
+#define TXR 0 /* Transmit register (WRITE) */
+#define RXR 0 /* Receive register (READ) */
+#define IER 1 /* Interrupt Enable */
+#define IIR 2 /* Interrupt ID */
+#define FCR 2 /* FIFO control */
+#define LCR 3 /* Line control */
+#define MCR 4 /* Modem control */
+#define LSR 5 /* Line Status */
+#define MSR 6 /* Modem Status */
+#define DLL 0 /* Divisor Latch Low */
+#define DLH 1 /* Divisor latch High */
+
+static int early_serial_putc(unsigned char ch)
+{
+ unsigned timeout = 0xffff;
+ while ((inb(early_serial_base + LSR) & XMTRDY) == 0 && --timeout)
+ cpu_relax();
+ outb(ch, early_serial_base + TXR);
+ return timeout ? 0 : -1;
+}
+
+static void early_serial_write(struct console *con, const char *s, unsigned n)
+{
+ while (*s && n-- > 0) {
+ early_serial_putc(*s);
+ if (*s == '\n')
+ early_serial_putc('\r');
+ s++;
+ }
+}
+
+#define DEFAULT_BAUD 9600
+
+static __init void early_serial_init(char *s)
+{
+ unsigned char c;
+ unsigned divisor;
+ unsigned baud = DEFAULT_BAUD;
+ char *e;
+
+ if (*s == ',')
+ ++s;
+
+ if (*s) {
+ unsigned port;
+ if (!strncmp(s,"0x",2)) {
+ early_serial_base = simple_strtoul(s, &e, 16);
+ } else {
+ static int bases[] = { 0x3f8, 0x2f8 };
+
+ if (!strncmp(s,"ttyS",4))
+ s += 4;
+ port = simple_strtoul(s, &e, 10);
+ if (port > 1 || s == e)
+ port = 0;
+ early_serial_base = bases[port];
+ }
+ s += strcspn(s, ",");
+ if (*s == ',')
+ s++;
+ }
+
+ outb(0x3, early_serial_base + LCR); /* 8n1 */
+ outb(0, early_serial_base + IER); /* no interrupt */
+ outb(0, early_serial_base + FCR); /* no fifo */
+ outb(0x3, early_serial_base + MCR); /* DTR + RTS */
+
+ if (*s) {
+ baud = simple_strtoul(s, &e, 0);
+ if (baud == 0 || s == e)
+ baud = DEFAULT_BAUD;
+ }
+
+ divisor = 115200 / baud;
+ c = inb(early_serial_base + LCR);
+ outb(c | DLAB, early_serial_base + LCR);
+ outb(divisor & 0xff, early_serial_base + DLL);
+ outb((divisor >> 8) & 0xff, early_serial_base + DLH);
+ outb(c & ~DLAB, early_serial_base + LCR);
+}
+#else
+
+static void
+early_serial_write(struct console *con, const char *s, unsigned count)
+{
+ int n;
+
+ while (count > 0) {
+ n = HYPERVISOR_console_io(CONSOLEIO_write, count, (char *)s);
+ if (n <= 0)
+ break;
+ count -= n;
+ s += n;
+ }
+}
+
+static __init void early_serial_init(char *s)
+{
+}
+#endif
+
+static struct console early_serial_console = {
+ .name = "earlyser",
+ .write = early_serial_write,
+ .flags = CON_PRINTBUFFER,
+ .index = -1,
+};
+
+/* Direct interface for emergencies */
+struct console *early_console = &early_vga_console;
+static int early_console_initialized = 0;
+
+void early_printk(const char *fmt, ...)
+{
+ char buf[512];
+ int n;
+ va_list ap;
+
+ va_start(ap,fmt);
+ n = vscnprintf(buf,512,fmt,ap);
+ early_console->write(early_console,buf,n);
+ va_end(ap);
+}
+
+static int keep_early;
+
+int __init setup_early_printk(char *opt)
+{
+ char *space;
+ char buf[256];
+
+ if (early_console_initialized)
+ return -1;
+
+ opt = strchr(opt, '=') + 1;
+
+ strlcpy(buf,opt,sizeof(buf));
+ space = strchr(buf, ' ');
+ if (space)
+ *space = 0;
+
+ if (strstr(buf,"keep"))
+ keep_early = 1;
+
+ if (!strncmp(buf, "serial", 6)) {
+ early_serial_init(buf + 6);
+ early_console = &early_serial_console;
+ } else if (!strncmp(buf, "ttyS", 4)) {
+ early_serial_init(buf);
+ early_console = &early_serial_console;
+ } else if (!strncmp(buf, "vga", 3)) {
+ early_console = &early_vga_console;
+ }
+ early_console_initialized = 1;
+ register_console(early_console);
+ return 0;
+}
+
+void __init disable_early_printk(void)
+{
+ if (!early_console_initialized || !early_console)
+ return;
+ if (!keep_early) {
+ printk("disabling early console\n");
+ unregister_console(early_console);
+ early_console_initialized = 0;
+ } else {
+ printk("keeping early console\n");
+ }
+}
+
+__setup("earlyprintk=", setup_early_printk);
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