From 64d191a88235f60a4a656eab40f844529815a8cf Mon Sep 17 00:00:00 2001
From: Jonas 'Sortie' Termansen <sortie@maxsi.org>
Date: Fri, 12 Aug 2011 15:13:18 +0200
Subject: [PATCH] x86 now has a driver for rebooting.

---
 sortix/x86/x86.cpp | 35 +++++++++++++++++++++++++++++++++++
 sortix/x86/x86.h   |  2 ++
 2 files changed, 37 insertions(+)

diff --git a/sortix/x86/x86.cpp b/sortix/x86/x86.cpp
index 5d7d5995..4abfbbc7 100644
--- a/sortix/x86/x86.cpp
+++ b/sortix/x86/x86.cpp
@@ -64,5 +64,40 @@ namespace Sortix
 			asm volatile("inl %1, %0" : "=a" (Result) : "dN" (Port));
 			return Result;
 		}
+
+		void Reboot()
+		{
+			// Keyboard interface IO port: data and control.
+			const uint16_t KEYBOARD_INTERFACE = 0x64;
+
+			// Keyboard IO port.
+			const uint16_t KEYBOARD_IO = 0x60;
+
+			// Keyboard data is in buffer (output buffer is empty) (bit 0).
+			const uint8_t KEYBOARD_DATA = (1<<0);
+
+			// User data is in buffer (command buffer is empty) (bit 1).
+			const uint8_t USER_DATA = (1<<1);
+
+			// Disable interrupts.
+			asm volatile("cli");
+
+			// Clear all keyboard buffers (output and command buffers).
+			uint8_t byte;
+			do
+			{
+				byte = InPortB(KEYBOARD_INTERFACE);
+				if ( ( byte & KEYBOARD_DATA ) != 0 ) { InPortB(KEYBOARD_IO); }
+			} while ( ( byte & USER_DATA ) != 0 );
+
+			// CPU reset command.
+			uint8_t KEYBOARD_RESET_CPU = 0xFE;
+
+			// Now pulse the CPU reset line and reset.
+			OutPortB(KEYBOARD_INTERFACE, KEYBOARD_RESET_CPU);
+
+			// If that didn't work, just halt.
+			asm volatile("hlt");
+		}
 	}
 }
diff --git a/sortix/x86/x86.h b/sortix/x86/x86.h
index 573767c8..4604f4da 100644
--- a/sortix/x86/x86.h
+++ b/sortix/x86/x86.h
@@ -44,6 +44,8 @@ namespace Sortix
 			uint32_t int_no, err_code; // Interrupt number and error code (if applicable)
 			uint32_t eip, cs, eflags, useresp, ss; // Pushed by the processor automatically.
 		};
+
+		void Reboot();
 	}
 }