[PATCH 02/10] drm/i915/display: Update calculation to avoid overflow

[Ankit Nautiyal]

From: Mitul Golani <mitulkumar.ajitkumar.golani at intel.com>

Update calculation to avoid overflow.

Fixes: 1676ecd303ac ("drm/i915: Compute CMRR and calculate vtotal")
Cc: Mitul Golani <mitulkumar.ajitkumar.golani at intel.com>
Cc: Ankit Nautiyal <ankit.k.nautiyal at intel.com>
Cc: Suraj Kandpal <suraj.kandpal at intel.com>
Cc: Jani Nikula <jani.nikula at linux.intel.com>
Cc: Stephen Rothwell <sfr at canb.auug.org.au>

Signed-off-by: Mitul Golani <mitulkumar.ajitkumar.golani at intel.com>
Reviewed-by: Ankit Nautiyal <ankit.k.nautiyal at intel.com>
---
 drivers/gpu/drm/i915/display/intel_vrr.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_vrr.c b/drivers/gpu/drm/i915/display/intel_vrr.c
index eb5b62b54d32..6430da25957d 100644
--- a/drivers/gpu/drm/i915/display/intel_vrr.c
+++ b/drivers/gpu/drm/i915/display/intel_vrr.c
@@ -147,10 +147,11 @@ cmrr_get_vtotal(struct intel_crtc_state *crtc_state, bool video_mode_required)
 		multiplier_n = 1000;
 	}
 
-	crtc_state->cmrr.cmrr_n =
-		desired_refresh_rate * adjusted_mode->crtc_htotal * multiplier_n;
-	vtotal = (adjusted_mode->crtc_clock * 1000 * multiplier_n) / crtc_state->cmrr.cmrr_n;
-	adjusted_pixel_rate = adjusted_mode->crtc_clock * 1000 * multiplier_m;
+	crtc_state->cmrr.cmrr_n = mul_u32_u32(desired_refresh_rate * adjusted_mode->crtc_htotal,
+					      multiplier_n);
+	vtotal = DIV_ROUND_UP_ULL(mul_u32_u32(adjusted_mode->crtc_clock * 1000, multiplier_n),
+				  crtc_state->cmrr.cmrr_n);
+	adjusted_pixel_rate = mul_u32_u32(adjusted_mode->crtc_clock * 1000, multiplier_m);
 	crtc_state->cmrr.cmrr_m = do_div(adjusted_pixel_rate, crtc_state->cmrr.cmrr_n);
 
 	return vtotal;
-- 
2.40.1