[coreboot-gerrit] Change in coreboot[master]: soc/rockchip/rk3399: Use 64 bits in multiplication

[Patrick Georgi (Code Review)]

Patrick Georgi has submitted this change and it was merged. ( https://review.coreboot.org/c/coreboot/+/34524 )

Change subject: soc/rockchip/rk3399: Use 64 bits in multiplication
......................................................................

soc/rockchip/rk3399: Use 64 bits in multiplication

This multiplication is of the form u64 = u32 * u32. Despite being stored
in a 64 bit variable, the intermediate value is still calculated using
32 bit math, which could possibly overflow. Cast one of the variables to
a u64 to ensure it uses 64 bit math instead to avoid this.

Change-Id: Ib08624812e933fdca5a51150ab36d3be49383326
Signed-off-by: Jacob Garber 
Found-by: Coverity CID 1375443
Reviewed-on: https://review.coreboot.org/c/coreboot/+/34524
Tested-by: build bot (Jenkins) 
Reviewed-by: Julius Werner 
Reviewed-by: Paul Menzel 
---
M src/soc/rockchip/rk3399/mipi.c
1 file changed, 1 insertion(+), 1 deletion(-)

Approvals:
  build bot (Jenkins): Verified
  Paul Menzel: Looks good to me, but someone else must approve
  Julius Werner: Looks good to me, approved

diff --git a/src/soc/rockchip/rk3399/mipi.c b/src/soc/rockchip/rk3399/mipi.c
index 1f3f02c..8b80bd7 100644
--- a/src/soc/rockchip/rk3399/mipi.c
+++ b/src/soc/rockchip/rk3399/mipi.c
@@ -305,7 +305,7 @@
    	       dsi->format);
    	return bpp;
    }
-	pclk = edid->mode.pixel_clock * MSECS_PER_SEC;
+	pclk = (u64)edid->mode.pixel_clock * MSECS_PER_SEC;

/* take 1 / 0.8, since mbps must bigger than bandwidth of RGB */
    target_bps = pclk / panel_data->lanes * bpp / 8 * 10;