LinuxKPI: make bcd.h use libkern

Rather than having code to re-define bcd2bin() for the LinuxKPI
make sure libkern.h is always included before the LinuxKPI version.
Then only re-define our local LinuxKPI implementation.  [1]

From the argument truncating wrapper call the libkern version.
If we change our libkern implementation in the future we can save
us the remainder of the hassle. [2]  Given I need this to MFC,
which I am not sure we can with libkern, commit this intermediate
step.

Suggested by:	Johannes Berg (johannes sipsolutions.net) [1]
Suggested by:	ian [2]
Sponsored by:	The FreeBSD Foundation
MFC after:	3 days
X-MFC with:	548ada00e54a9e7745d041b1ec7f68f3bd493365
Differential Revision: https://reviews.freebsd.org/D32695

1 files changed, 3 insertions, 11 deletions

diff --git a/sys/compat/linuxkpi/common/include/linux/bcd.h b/sys/compat/linuxkpi/common/include/linux/bcd.h
index 57fcb4c6bd98..8a40da1a330b 100644
--- a/sys/compat/linuxkpi/common/include/linux/bcd.h
+++ b/sys/compat/linuxkpi/common/include/linux/bcd.h
@@ -31,23 +31,15 @@
 #define	_LINUXKPI_LINUX_BCD_H
 
 #include <sys/types.h>
+#include <sys/libkern.h>
 
-/*
- * We could use libkern, but we need the argument truncating.
- *
- * This leaves us with a duplicate symbol with conflicting types
- * so we cannot simply re-define as libkern.h gets included in
- * too many places directly or indirectly.  This means for now
- * drivers will have to be adjusted to call linuxkpi_bcd2bin().
- */
+/* Compared to the libkern version this one truncates the argument. */
 static inline uint8_t linuxkpi_bcd2bin(uint8_t x)
 {
 
-	return (x & 0x0f) + (x >> 4) * 10;
+	return (bcd2bin(x));
 }
 
-#if 0
 #define	bcd2bin(_x)	linuxkpi_bcd2bin(_x)
-#endif
 
 #endif	/* _LINUXKPI_LINUX_BCD_H */