1 files changed, 152 insertions, 0 deletions
diff --git a/purgatory/arch/i386/vga.c b/purgatory/arch/i386/vga.c
new file mode 100644
index 0000000..e65976c
--- /dev/null
+++ b/purgatory/arch/i386/vga.c
@@ -0,0 +1,152 @@
+#include <sys/io.h>
+#include <purgatory.h>
+#include "purgatory-x86.h"
+
+/* Crudely reset a VGA card to text mode 3, by writing plausible default    */
+/* values into its registers.                                               */
+/* Tim Deegan (tjd21 at cl.cam.ac.uk), March 2003                              */
+/* Based on Keir Fraser's start-of-day reset code from the Xen hypervisor   */
+/* Converted from Assembly 20 December 2004 -- Eric Biederman */
+
+void x86_reset_vga(void)
+{
+	/* Hello */
+	inb(0x3da);
+	outb(0, 0x3c0);
+
+	/* Sequencer registers */
+	outw(0x0300, 0x3c4);
+	outw(0x0001, 0x3c4);
+	outw(0x0302, 0x3c4);
+	outw(0x0003, 0x3c4);
+	outw(0x0204, 0x3c4);
+
+	/* Ensure CRTC regs 0-7 are unlocked by clearing bit 7 of CRTC[17] */
+	outw(0x0e11, 0x3d4);
+	/* CRTC registers */
+	outw(0x5f00, 0x3d4);
+	outw(0x4f01, 0x3d4);
+	outw(0x5002, 0x3d4);
+	outw(0x8203, 0x3d4);
+	outw(0x5504, 0x3d4);
+	outw(0x8105, 0x3d4);
+	outw(0xbf06, 0x3d4);
+	outw(0x1f07, 0x3d4);
+	outw(0x0008, 0x3d4);
+	outw(0x4f09, 0x3d4);
+	outw(0x200a, 0x3d4);
+	outw(0x0e0b, 0x3d4);
+	outw(0x000c, 0x3d4);
+	outw(0x000d, 0x3d4);
+	outw(0x010e, 0x3d4);
+	outw(0xe00f, 0x3d4);
+	outw(0x9c10, 0x3d4);
+	outw(0x8e11, 0x3d4);
+	outw(0x8f12, 0x3d4);
+	outw(0x2813, 0x3d4);
+	outw(0x1f14, 0x3d4);
+	outw(0x9615, 0x3d4);
+	outw(0xb916, 0x3d4);
+	outw(0xa317, 0x3d4);
+	outw(0xff18, 0x3d4);
+
+	/* Graphic registers */
+	outw(0x0000, 0x3ce);
+	outw(0x0001, 0x3ce);
+	outw(0x0002, 0x3ce);
+	outw(0x0003, 0x3ce);
+	outw(0x0004, 0x3ce);
+	outw(0x1005, 0x3ce);
+	outw(0x0e06, 0x3ce);
+	outw(0x0007, 0x3ce);
+	outw(0xff08, 0x3ce);
+
+	/* Attribute registers */
+	inb(0x3da);
+	outb(0x00, 0x3c0);
+	outb(0x00, 0x3c0);
+
+	inb(0x3da);
+	outb(0x01, 0x3c0);
+	outb(0x01, 0x3c0);
+
+	inb(0x3da);
+	outb(0x02, 0x3c0);
+	outb(0x02, 0x3c0);
+
+	inb(0x3da);
+	outb(0x03, 0x3c0);
+	outb(0x03, 0x3c0);
+
+	inb(0x3da);
+	outb(0x04, 0x3c0);
+	outb(0x04, 0x3c0);
+
+	inb(0x3da);
+	outb(0x05, 0x3c0);
+	outb(0x05, 0x3c0);
+
+	inb(0x3da);
+	outb(0x06, 0x3c0);
+	outb(0x14, 0x3c0);
+
+	inb(0x3da);
+	outb(0x07, 0x3c0);
+	outb(0x07, 0x3c0);
+
+	inb(0x3da);
+	outb(0x08, 0x3c0);
+	outb(0x38, 0x3c0);
+
+	inb(0x3da);
+	outb(0x09, 0x3c0);
+	outb(0x39, 0x3c0);
+
+	inb(0x3da);
+	outb(0x0a, 0x3c0);
+	outb(0x3a, 0x3c0);
+
+	inb(0x3da);
+	outb(0x0b, 0x3c0);
+	outb(0x3b, 0x3c0);
+
+	inb(0x3da);
+	outb(0x0c, 0x3c0);
+	outb(0x3c, 0x3c0);
+
+	inb(0x3da);
+	outb(0x0d, 0x3c0);
+	outb(0x3d, 0x3c0);
+
+	inb(0x3da);
+	outb(0x0e, 0x3c0);
+	outb(0x3e, 0x3c0);
+
+	inb(0x3da);
+	outb(0x0f, 0x3c0);
+	outb(0x3f, 0x3c0);
+
+	inb(0x3da);
+	outb(0x10, 0x3c0);
+	outb(0x0c, 0x3c0);
+
+	inb(0x3da);
+	outb(0x11, 0x3c0);
+	outb(0x00, 0x3c0);
+
+	inb(0x3da);
+	outb(0x12, 0x3c0);
+	outb(0x0f, 0x3c0);
+
+	inb(0x3da);
+	outb(0x13, 0x3c0);
+	outb(0x08, 0x3c0);
+
+	inb(0x3da);
+	outb(0x14, 0x3c0);
+	outb(0x00, 0x3c0);
+
+	/* Goodbye */
+	inb(0x3da);
+	outb(0x20, 0x3c0);
+}