ia64/xen: define helper functions for xen related address conversion.

Xen needs some address conversions between pseudo physical
address (guest phsyical address), guest machine address
(real machine address) and dma address.
Define helper functions for those address conversion.

Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: Isaku Yamahata <yamahata@valinux.co.jp>
Signed-off-by: Tony Luck <tony.luck@intel.com>

arch/ia64/include/asm/xen/page.h

+/******************************************************************************
+ * arch/ia64/include/asm/xen/page.h
+ *
+ * Copyright (c) 2008 Isaku Yamahata <yamahata at valinux co jp>
+ *                    VA Linux Systems Japan K.K.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ */
+
+#ifndef _ASM_IA64_XEN_PAGE_H
+#define _ASM_IA64_XEN_PAGE_H
+
+#define INVALID_P2M_ENTRY	(~0UL)
+
+static inline unsigned long mfn_to_pfn(unsigned long mfn)
+{
+	return mfn;
+}
+
+static inline unsigned long pfn_to_mfn(unsigned long pfn)
+{
+	return pfn;
+}
+
+#define phys_to_machine_mapping_valid(_x)	(1)
+
+static inline void *mfn_to_virt(unsigned long mfn)
+{
+	return __va(mfn << PAGE_SHIFT);
+}
+
+static inline unsigned long virt_to_mfn(void *virt)
+{
+	return __pa(virt) >> PAGE_SHIFT;
+}
+
+/* for tpmfront.c */
+static inline unsigned long virt_to_machine(void *virt)
+{
+	return __pa(virt);
+}
+
+static inline void set_phys_to_machine(unsigned long pfn, unsigned long mfn)
+{
+	/* nothing */
+}
+
+#define pte_mfn(_x)	pte_pfn(_x)
+#define mfn_pte(_x, _y)	__pte_ma(0)		/* unmodified use */
+#define __pte_ma(_x)	((pte_t) {(_x)})        /* unmodified use */
+
+#endif /* _ASM_IA64_XEN_PAGE_H */