[OpenBIOS] [PATCH 4/7] OFMEM: Fix bad alignments passed into the OFMEM claim words

[Mark Cave-Ayland]

If a memory claim is made with an alignment that is not an exact power of
2, round up to the nearest power of 2 as per the IEEE1275 specification
rather than switching to a 4K default.

Also we make sure that the minimum alignment is equivalent to PAGE_SIZE.

Signed-off-by: Mark Cave-Ayland <mark.cave-ayland at ilande.co.uk>
---
 openbios-devel/libopenbios/ofmem_common.c |   20 +++++++++++++++++---
 1 file changed, 17 insertions(+), 3 deletions(-)

diff --git a/openbios-devel/libopenbios/ofmem_common.c b/openbios-devel/libopenbios/ofmem_common.c
index 4c464c8..ee8ee82 100644
--- a/openbios-devel/libopenbios/ofmem_common.c
+++ b/openbios-devel/libopenbios/ofmem_common.c
@@ -425,13 +425,27 @@ static ucell find_area( ucell align, ucell size, range_t *r,
 {
 	phys_addr_t base = min;
 	range_t *r2;
+	ucell old_align;
+	int i;
 
 	if( (align & (align-1)) ) {
-		OFMEM_TRACE("bad alignment " FMT_ucell "\n", align);
-		align = 0x1000;
+	
+		/* As per IEEE1275 specification, round up to the nearest power of 2 */
+		old_align = align;
+		if (old_align <= PAGE_SIZE) {
+			align = PAGE_SIZE;
+		} else {
+			align--;
+			for (i = 1; i < sizeof(ucell) * 8; i<<=1) {
+				align |= align >> i;
+			}
+			align++;
+		}
+		
+		OFMEM_TRACE("warning: bad alignment " FMT_ucellx " rounded up to " FMT_ucellx "\n", old_align, align);
 	}
 	if( !align )
-		align = 0x1000;
+		align = PAGE_SIZE;
 
 	base = reverse ? max - size : min;
 	r2 = reverse ? NULL : r;
-- 
1.7.10.4