[PATCH 2/5] include: Add round_up/round_down macros from kernel

[Sascha Hauer]

Yes, we already have roundup/rounddown. Unlike these macros
round_up/round_down are optimized to (and only work with)
power-of-2 arguments. It's a poor name, but kernel code needs
it, so add it to barebox aswell.

Signed-off-by: Sascha Hauer <s.hauer at pengutronix.de>
---
 include/linux/kernel.h | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index 4322f01..b90d8f7 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -5,6 +5,19 @@
 #include <linux/barebox-wrapper.h>
 
 /*
+ * This looks more complex than it should be. But we need to
+ * get the type for the ~ right in round_down (it needs to be
+ * as wide as the result!), and we want to evaluate the macro
+ * arguments just once each.
+ *
+ * NOTE these functions only round to power-of-2 arguments. Use
+ * roundup/rounddown for non power-of-2-arguments.
+ */
+#define __round_mask(x, y) ((__typeof__(x))((y)-1))
+#define round_up(x, y) ((((x)-1) | __round_mask(x, y))+1)
+#define round_down(x, y) ((x) & ~__round_mask(x, y))
+
+/*
  * min()/max()/clamp() macros that also do
  * strict type-checking.. See the
  * "unnecessary" pointer comparison.
-- 
2.0.1