From 36a8ed9e315bd35d54e14411f78dbc3a9f2b5747 Mon Sep 17 00:00:00 2001
From: Stefan Lankes <lankes@lfbs.rwth-aachen.de>
Date: Mon, 18 Jul 2011 09:06:09 +0200
Subject: [PATCH] add helper functions for reading and writing CMOS entries

---
 arch/x86/include/asm/io.h | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/arch/x86/include/asm/io.h b/arch/x86/include/asm/io.h
index 8765b7cc..0a97a187 100644
--- a/arch/x86/include/asm/io.h
+++ b/arch/x86/include/asm/io.h
@@ -32,6 +32,13 @@
 extern "C" {
 #endif
 
+#ifndef CMOS_PORT_ADDRESS
+#define CMOS_PORT_ADDRESS	0x70
+#endif
+#ifndef CMOS_PORT_DATA
+#define CMOS_PORT_DATA		0x71
+#endif
+
 /** @brief Read a byte from an IO port
  *
  * @param _port The port you want to read from
@@ -98,6 +105,28 @@ inline static void uart_putchar(unsigned char _data)
 	outportb(0x2F8, _data);
 }
 
+/**
+ * read a byte from CMOS
+ *  @param offset CMOS offset
+ *  @return value you want to read
+ */
+inline static uint8_t cmos_read(uint8_t offset)
+{
+	outportb(CMOS_PORT_ADDRESS, offset);
+	return inportb(CMOS_PORT_DATA);
+}
+ 
+/**
+ * write a byte in CMOS
+ *  @param offset CMOS offset
+ *  @param val the value you want wto write
+ */
+inline static void cmos_write(uint8_t offset, uint8_t val)
+{
+	outportb(CMOS_PORT_ADDRESS, offset);
+	outportb(CMOS_PORT_DATA, val);
+}
+
 #ifdef __cplusplus
 }
 #endif