arch/tile: various header improvements for building drivers

This change adds a number of missing headers in asm (fb.h, parport.h,
serial.h, and vga.h) using the minimal generic versions.

It also adds a number of missing interfaces that showed up as build
failures when trying to build various drivers not normally included in the
"tile" distribution: ioremap_wc(), memset_io(), io{read,write}{16,32}be(),
virt_to_bus(), bus_to_virt(), irq_canonicalize(), __pte(), __pgd(),
and __pmd().  I also added a cast in virt_to_page() since not all callers
pass a pointer.

I fixed <asm/stat.h> to properly include a __KERNEL__ guard for the
__ARCH_WANT_STAT64 symbol, and <asm/swab.h> to use __builtin_bswap32()
even for our 64-bit architecture, since the same code is produced.

I added an export for get_cycles(), since it's used in some modules.

And I made <arch/spr_def.h> properly include the __KERNEL__ guard,
even though it's not yet exported, since it likely will be soon.

Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>

arch/tile/include/asm/vga.h

@@ -0,0 +1,39 @@
+/*
+ * Copyright 2010 Tilera Corporation. All Rights Reserved.
+ *
+ *   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, version 2.
+ *
+ *   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, GOOD TITLE or
+ *   NON INFRINGEMENT.  See the GNU General Public License for
+ *   more details.
+ *
+ * Access to VGA videoram.
+ */
+
+#ifndef _ASM_TILE_VGA_H
+#define _ASM_TILE_VGA_H
+
+#include <asm/io.h>
+
+#define VT_BUF_HAVE_RW
+
+static inline void scr_writew(u16 val, volatile u16 *addr)
+{
+	__raw_writew(val, (volatile u16 __iomem *) addr);
+}
+
+static inline u16 scr_readw(volatile const u16 *addr)
+{
+	return __raw_readw((volatile const u16 __iomem *) addr);
+}
+
+#define vga_readb(a)	readb((u8 __iomem *)(a))
+#define vga_writeb(v,a)	writeb(v, (u8 __iomem *)(a))
+
+#define VGA_MAP_MEM(x,s)	((unsigned long) ioremap(x, s))
+
+#endif