m68k/video: Create <asm/vga.h>

For now, it just contains the hack for cirrusfb on Amiga, which is moved
out of <video/vga.h> with some slight modifications (use raw_*() instead of
z_*(), which are defined on all m68k platforms).

This makes it safe to include <video/vga.h> in all contexts. Before it
could fail to compile with

include/video/vga.h: In function ‘vga_mm_r’:
include/video/vga.h:242: error: implicit declaration of function ‘z_readb’
include/video/vga.h: In function ‘vga_mm_w’:
include/video/vga.h:247: error: implicit declaration of function ‘z_writeb’
include/video/vga.h: In function ‘vga_mm_w_fast’:
include/video/vga.h:253: error: implicit declaration of function ‘z_writew’

or

include/video/vga.h:23:21: error: asm/vga.h: No such file or directory

depending on the value of CONFIG_AMIGA.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: linux-fbdev@vger.kernel.org
Cc: dri-devel@lists.freedesktop.org
diff --git a/arch/m68k/include/asm/vga.h b/arch/m68k/include/asm/vga.h
new file mode 100644
index 0000000..d3aa140
--- /dev/null
+++ b/arch/m68k/include/asm/vga.h
@@ -0,0 +1,27 @@
+#ifndef _ASM_M68K_VGA_H
+#define _ASM_M68K_VGA_H
+
+#include <asm/raw_io.h>
+
+/*
+ * FIXME
+ * Ugh, we don't have PCI space, so map readb() and friends to use raw I/O
+ * accessors, which are identical to the z_*() Zorro bus accessors.
+ * This should make cirrusfb work again on Amiga
+ */
+#undef inb_p
+#undef inw_p
+#undef outb_p
+#undef outw
+#undef readb
+#undef writeb
+#undef writew
+#define inb_p(port)		0
+#define inw_p(port)		0
+#define outb_p(port, val)	do { } while (0)
+#define outw(port, val)		do { } while (0)
+#define readb			raw_inb
+#define writeb			raw_outb
+#define writew			raw_outw
+
+#endif /* _ASM_M68K_VGA_H */