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Diffstat (limited to 'arch/x86/kernel/early_printk.c')
-rw-r--r--arch/x86/kernel/early_printk.c259
1 files changed, 259 insertions, 0 deletions
diff --git a/arch/x86/kernel/early_printk.c b/arch/x86/kernel/early_printk.c
new file mode 100644
index 00000000..9b9f18b4
--- /dev/null
+++ b/arch/x86/kernel/early_printk.c
@@ -0,0 +1,259 @@
+#include <linux/console.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/string.h>
+#include <linux/screen_info.h>
+#include <linux/usb/ch9.h>
+#include <linux/pci_regs.h>
+#include <linux/pci_ids.h>
+#include <linux/errno.h>
+#include <asm/io.h>
+#include <asm/processor.h>
+#include <asm/fcntl.h>
+#include <asm/setup.h>
+#include <xen/hvc-console.h>
+#include <asm/pci-direct.h>
+#include <asm/fixmap.h>
+#include <asm/mrst.h>
+#include <asm/pgtable.h>
+#include <linux/usb/ehci_def.h>
+
+/* Simple VGA output */
+#define VGABASE (__ISA_IO_base + 0xb8000)
+
+static int max_ypos = 25, max_xpos = 80;
+static int current_ypos = 25, current_xpos;
+
+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;
+ }
+#ifdef CONFIG_KGDB_KDB
+ if (c == '\b') {
+ if (current_xpos > 0)
+ current_xpos--;
+ } else if (c == '\r') {
+ current_xpos = 0;
+ } else
+#endif
+ 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,
+};
+
+/* Serial functions loosely based on a similar package from Klaus P. Gerlicher */
+
+static 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) {
+ if (*s == '\n')
+ early_serial_putc('\r');
+ early_serial_putc(*s);
+ 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 const int __initconst 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);
+}
+
+static struct console early_serial_console = {
+ .name = "earlyser",
+ .write = early_serial_write,
+ .flags = CON_PRINTBUFFER,
+ .index = -1,
+};
+
+/* Direct interface for emergencies */
+static struct console *early_console = &early_vga_console;
+static int __initdata early_console_initialized;
+
+asmlinkage void early_printk(const char *fmt, ...)
+{
+ char buf[512];
+ int n;
+ va_list ap;
+
+ va_start(ap, fmt);
+ n = vscnprintf(buf, sizeof(buf), fmt, ap);
+ early_console->write(early_console, buf, n);
+ va_end(ap);
+}
+
+static inline void early_console_register(struct console *con, int keep_early)
+{
+ if (early_console->index != -1) {
+ printk(KERN_CRIT "ERROR: earlyprintk= %s already used\n",
+ con->name);
+ return;
+ }
+ early_console = con;
+ if (keep_early)
+ early_console->flags &= ~CON_BOOT;
+ else
+ early_console->flags |= CON_BOOT;
+ register_console(early_console);
+}
+
+static int __init setup_early_printk(char *buf)
+{
+ int keep;
+
+ if (!buf)
+ return 0;
+
+ if (early_console_initialized)
+ return 0;
+ early_console_initialized = 1;
+
+ keep = (strstr(buf, "keep") != NULL);
+
+ while (*buf != '\0') {
+ if (!strncmp(buf, "serial", 6)) {
+ buf += 6;
+ early_serial_init(buf);
+ early_console_register(&early_serial_console, keep);
+ if (!strncmp(buf, ",ttyS", 5))
+ buf += 5;
+ }
+ if (!strncmp(buf, "ttyS", 4)) {
+ early_serial_init(buf + 4);
+ early_console_register(&early_serial_console, keep);
+ }
+ if (!strncmp(buf, "vga", 3) &&
+ boot_params.screen_info.orig_video_isVGA == 1) {
+ max_xpos = boot_params.screen_info.orig_video_cols;
+ max_ypos = boot_params.screen_info.orig_video_lines;
+ current_ypos = boot_params.screen_info.orig_y;
+ early_console_register(&early_vga_console, keep);
+ }
+#ifdef CONFIG_EARLY_PRINTK_DBGP
+ if (!strncmp(buf, "dbgp", 4) && !early_dbgp_init(buf + 4))
+ early_console_register(&early_dbgp_console, keep);
+#endif
+#ifdef CONFIG_HVC_XEN
+ if (!strncmp(buf, "xen", 3))
+ early_console_register(&xenboot_console, keep);
+#endif
+#ifdef CONFIG_EARLY_PRINTK_INTEL_MID
+ if (!strncmp(buf, "mrst", 4)) {
+ mrst_early_console_init();
+ early_console_register(&early_mrst_console, keep);
+ }
+
+ if (!strncmp(buf, "hsu", 3)) {
+ hsu_early_console_init(buf + 3);
+ early_console_register(&early_hsu_console, keep);
+ }
+#endif
+ buf++;
+ }
+ return 0;
+}
+
+early_param("earlyprintk", setup_early_printk);
generated by cgit (git 2.34.1) at 2025-01-15 16:09:10 +0000