1 files changed, 83 insertions, 0 deletions
diff --git a/arch/x86/realmode/rm/wakemain.c b/arch/x86/realmode/rm/wakemain.c
new file mode 100644
index 000000000..1d6437e6d
--- /dev/null
+++ b/arch/x86/realmode/rm/wakemain.c
@@ -0,0 +1,83 @@
+// SPDX-License-Identifier: GPL-2.0
+#include "wakeup.h"
+#include "boot.h"
+
+static void udelay(int loops)
+{
+	while (loops--)
+		io_delay();	/* Approximately 1 us */
+}
+
+static void beep(unsigned int hz)
+{
+	u8 enable;
+
+	if (!hz) {
+		enable = 0x00;		/* Turn off speaker */
+	} else {
+		u16 div = 1193181/hz;
+
+		outb(0xb6, 0x43);	/* Ctr 2, squarewave, load, binary */
+		io_delay();
+		outb(div, 0x42);	/* LSB of counter */
+		io_delay();
+		outb(div >> 8, 0x42);	/* MSB of counter */
+		io_delay();
+
+		enable = 0x03;		/* Turn on speaker */
+	}
+	inb(0x61);		/* Dummy read of System Control Port B */
+	io_delay();
+	outb(enable, 0x61);	/* Enable timer 2 output to speaker */
+	io_delay();
+}
+
+#define DOT_HZ		880
+#define DASH_HZ		587
+#define US_PER_DOT	125000
+
+/* Okay, this is totally silly, but it's kind of fun. */
+static void send_morse(const char *pattern)
+{
+	char s;
+
+	while ((s = *pattern++)) {
+		switch (s) {
+		case '.':
+			beep(DOT_HZ);
+			udelay(US_PER_DOT);
+			beep(0);
+			udelay(US_PER_DOT);
+			break;
+		case '-':
+			beep(DASH_HZ);
+			udelay(US_PER_DOT * 3);
+			beep(0);
+			udelay(US_PER_DOT);
+			break;
+		default:	/* Assume it's a space */
+			udelay(US_PER_DOT * 3);
+			break;
+		}
+	}
+}
+
+void main(void)
+{
+	/* Kill machine if structures are wrong */
+	if (wakeup_header.real_magic != 0x12345678)
+		while (1)
+			;
+
+	if (wakeup_header.realmode_flags & 4)
+		send_morse("...-");
+
+	if (wakeup_header.realmode_flags & 1)
+		asm volatile("lcallw   $0xc000,$3");
+
+	if (wakeup_header.realmode_flags & 2) {
+		/* Need to call BIOS */
+		probe_cards(0);
+		set_mode(wakeup_header.video_mode);
+	}
+}