[PATCH] Consolidate check_signature

There's nothing arch-specific about check_signature(), so move it to
<linux/io.h>.  Use a cross between the Alpha and i386 implementations as
the generic one.

Signed-off-by: Matthew Wilcox <willy@parisc-linux.org>
Acked-by: Alan Cox <alan@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/include/linux/io.h b/include/linux/io.h
index 2ad96c3..81877ea 100644
--- a/include/linux/io.h
+++ b/include/linux/io.h
@@ -28,4 +28,31 @@
 int ioremap_page_range(unsigned long addr, unsigned long end,
 		       unsigned long phys_addr, pgprot_t prot);
 
+/**
+ *	check_signature		-	find BIOS signatures
+ *	@io_addr: mmio address to check
+ *	@signature:  signature block
+ *	@length: length of signature
+ *
+ *	Perform a signature comparison with the mmio address io_addr. This
+ *	address should have been obtained by ioremap.
+ *	Returns 1 on a match.
+ */
+
+static inline int check_signature(const volatile void __iomem *io_addr,
+	const unsigned char *signature, int length)
+{
+	int retval = 0;
+	do {
+		if (readb(io_addr) != *signature)
+			goto out;
+		io_addr++;
+		signature++;
+		length--;
+	} while (length);
+	retval = 1;
+out:
+	return retval;
+}
+
 #endif /* _LINUX_IO_H */