diff --git a/include/linux/mc6821.h b/include/linux/mc6821.h
new file mode 100644
index 0000000..28e301e
--- /dev/null
+++ b/include/linux/mc6821.h
@@ -0,0 +1,51 @@
+#ifndef _MC6821_H_
+#define _MC6821_H_
+
+/*
+ * This file describes the memery mapping of the MC6821 PIA.
+ * The unions describe overlayed registers. Which of them is used is
+ * determined by bit 2 of the corresponding control register.
+ * this files expects the PIA_REG_PADWIDTH to be defined the numeric
+ * value of the register spacing.
+ *
+ * Data came from MFC-31-Developer Kit (from Ralph Seidel,
+ * zodiac@darkness.gun.de) and Motorola Data Sheet (from 
+ * Richard Hirst, srh@gpt.co.uk)
+ *
+ * 6.11.95 copyright Joerg Dorchain (dorchain@mpi-sb.mpg.de)
+ *
+ */
+
+#ifndef PIA_REG_PADWIDTH
+#define PIA_REG_PADWIDTH 255
+#endif
+
+struct pia {
+	union {
+		volatile u_char pra;
+		volatile u_char ddra;
+	} ua;
+	u_char pad1[PIA_REG_PADWIDTH];
+	volatile u_char cra;
+	u_char pad2[PIA_REG_PADWIDTH];
+	union {
+		volatile u_char prb;
+		volatile u_char ddrb;
+	} ub;
+	u_char pad3[PIA_REG_PADWIDTH];
+	volatile u_char crb;
+	u_char pad4[PIA_REG_PADWIDTH];
+};
+
+#define ppra ua.pra
+#define pddra ua.ddra
+#define pprb ub.prb
+#define pddrb ub.ddrb
+
+#define PIA_C1_ENABLE_IRQ (1<<0)
+#define PIA_C1_LOW_TO_HIGH (1<<1)
+#define PIA_DDR (1<<2)
+#define PIA_IRQ2 (1<<6)
+#define PIA_IRQ1 (1<<7)
+
+#endif