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-rw-r--r--include/linux/io.h27
1 files changed, 27 insertions, 0 deletions
diff --git a/include/linux/io.h b/include/linux/io.h
index 2ad96c3f0e4e..81877ea39309 100644
--- a/include/linux/io.h
+++ b/include/linux/io.h
@@ -28,4 +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 */