Define MAX_UDELAY_MS

    
If HZ was 1000, mdelay(2) cause overflow on multiplication in
__udelay.  We should define MAX_UDELAY_MS properly to prevent this.
    
Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 9 insertions, 0 deletions

diff --git a/include/asm-mips/delay.h b/include/asm-mips/delay.h
index 85435a8d4e52..48d00cccdafa 100644
--- a/include/asm-mips/delay.h
+++ b/include/asm-mips/delay.h
@@ -84,4 +84,13 @@ static inline void __udelay(unsigned long usecs, unsigned long lpj)
 
 #define udelay(usecs) __udelay((usecs),__udelay_val)
 
+/* make sure "usecs *= ..." in udelay do not overflow. */
+#if HZ >= 1000
+#define MAX_UDELAY_MS   1
+#elif HZ <= 200
+#define MAX_UDELAY_MS   5
+#else
+#define MAX_UDELAY_MS   (1000 / HZ)
+#endif
+
 #endif /* _ASM_DELAY_H */