[U-Boot] [PATCH v2] Fix wrong loop bound in flush_cache() when "size" is zero

[Yao Cheng]

The issue is found when calling flush_cache() with zero "size" argument.
The bound of loop is miscalculated in this case and flush_cache() enters a wrong flushing loop.
To fix this issue I skipped the operations when "size" is found to be zero.

Signed-off-by: Yao Cheng <saturdaycoder at gmail.com>
Cc: Shinya Kuribayashi<skuribay at pobox.com>
---
Changes for v2:
	- Coding style cleanup
	- Move code after declarations to avoid warning

 arch/mips/cpu/mips32/cpu.c |    5 +++++
 1 files changed, 5 insertions(+), 0 deletions(-)

diff --git a/arch/mips/cpu/mips32/cpu.c b/arch/mips/cpu/mips32/cpu.c
index 3ae397c..8fa53ba 100644
--- a/arch/mips/cpu/mips32/cpu.c
+++ b/arch/mips/cpu/mips32/cpu.c
@@ -56,6 +56,11 @@ void flush_cache(ulong start_addr, ulong size)
 	unsigned long addr = start_addr & ~(lsize - 1);
 	unsigned long aend = (start_addr + size - 1) & ~(lsize - 1);
 
+	/* aend will be miscalculated when size is zero, so we return here */
+	if (size == 0) {
+		return;
+	}
+
 	while (1) {
 		cache_op(Hit_Writeback_Inv_D, addr);
 		cache_op(Hit_Invalidate_I, addr);
-- 
1.7.4.1