[U-Boot] [PATCH 3/4] usb: ums: fix bug in partition capacity computation.

[Przemyslaw Marczak]

Before this change ums disk capacity was miscalculated because
of integer overflow.

Signed-off-by: Przemyslaw Marczak <p.marczak at samsung.com>
Cc: Marek Vasut <marex at denx.de>
---
 board/samsung/common/ums.c |   16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/board/samsung/common/ums.c b/board/samsung/common/ums.c
index 1f28590..6c4e6c4 100644
--- a/board/samsung/common/ums.c
+++ b/board/samsung/common/ums.c
@@ -37,11 +37,19 @@ static int ums_write_sector(struct ums *ums_dev,
 
 static void ums_get_capacity(struct ums *ums_dev, long long int *capacity)
 {
-	long long int tmp_capacity;
+	int64_t mmc_capacity = (int64_t)ums_dev->mmc->capacity;
+	int64_t ums_capacity = (int64_t)ums_dev->part_size * SECTOR_SIZE;
+	int64_t ums_offset = (int64_t)ums_dev->offset * SECTOR_SIZE;
 
-	tmp_capacity = (long long int)((ums_dev->offset + ums_dev->part_size)
-				       * SECTOR_SIZE);
-	*capacity = ums_dev->mmc->capacity - tmp_capacity;
+	if (ums_capacity && ((ums_capacity + ums_offset) < mmc_capacity))
+		*capacity = ums_capacity;
+	else
+		*capacity = mmc_capacity - ums_offset;
+
+	printf("UMS: partition capacity: %#llx blocks\n"
+	       "UMS: partition start block: %#x\n",
+	       *capacity / SECTOR_SIZE,
+	       ums_dev->offset);
 }
 
 static struct ums ums_dev = {
-- 
1.7.9.5