From: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
[ Upstream commit 47956bc86ee4e8530cac386a04f62a6095f7afbe ]
As nwl_dsi.lanes is u32, and NSEC_PER_SEC is 1000000000L, the second
multiplication in
dsi->lanes * 8 * NSEC_PER_SEC
will overflow on a 32-bit platform. Fix this by making the constant
unsigned long long, forcing 64-bit arithmetic.
As iMX8 is arm64, this driver is currently used on 64-bit platforms
only, where long is 64-bit, so this cannot happen. But the issue will
start to happen when the driver is reused for a 32-bit SoC (e.g.
i.MX7ULP), or when code is copied for a new driver.
Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
Reviewed-by: Fabio Estevam <festevam@xxxxxxxxx>
Reviewed-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
Signed-off-by: Sam Ravnborg <sam@xxxxxxxxxxxx>
Link: https://patchwork.freedesktop.org/patch/msgid/ebb82941a86b4e35c4fcfb1ef5a5cfad7c1fceab.1626255956.git.geert+renesas@xxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/gpu/drm/bridge/nwl-dsi.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/bridge/nwl-dsi.c b/drivers/gpu/drm/bridge/nwl-dsi.c
index 873995f0a741..6002404ffcb9 100644
--- a/drivers/gpu/drm/bridge/nwl-dsi.c
+++ b/drivers/gpu/drm/bridge/nwl-dsi.c
@@ -196,7 +196,7 @@ static u32 ps2bc(struct nwl_dsi *dsi, unsigned long long ps)
u32 bpp = mipi_dsi_pixel_format_to_bpp(dsi->format);
return DIV64_U64_ROUND_UP(ps * dsi->mode.clock * bpp,
- dsi->lanes * 8 * NSEC_PER_SEC);
+ dsi->lanes * 8ULL * NSEC_PER_SEC);
}
/*
--
2.30.2
