1 files changed, 28 insertions, 0 deletions

diff --git a/include/linux/io.h b/include/linux/io.h
index aa3f5af670b5..81877ea39309 100644
--- a/include/linux/io.h
+++ b/include/linux/io.h
@@ -18,6 +18,7 @@
 #ifndef _LINUX_IO_H
 #define _LINUX_IO_H
 
+#include <linux/types.h>
 #include <asm/io.h>
 #include <asm/page.h>
 
@@ -27,4 +28,31 @@ void __iowrite64_copy(void __iomem *to, const void *from, size_t count);
 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 */