[PATCH] drm/amd/display: fix 64 bit divide

[Guo, Bing]

[AMD Official Use Only]

Reviewed-by: Bing Guo < <Bing.Guo at amd.com >

-----Original Message-----
From: Deucher, Alexander <Alexander.Deucher at amd.com> 
Sent: Wednesday, November 24, 2021 11:36 AM
To: amd-gfx at lists.freedesktop.org
Cc: Deucher, Alexander <Alexander.Deucher at amd.com>; kernel test robot <lkp at intel.com>; Randy Dunlap <rdunlap at infradead.org>; Guo, Bing <Bing.Guo at amd.com>
Subject: [PATCH] drm/amd/display: fix 64 bit divide

Use do_div.

Fixes: c34f1652a18c4b ("drm/amd/display: fixed an error related to 4:2:0/4:2:2 DSC")
Reported-by: kernel test robot <lkp at intel.com>
Reported-by: Randy Dunlap <rdunlap at infradead.org>
Cc: Bing Guo <Bing.Guo at amd.com>
Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
---
 drivers/gpu/drm/amd/display/dc/dsc/rc_calc_dpi.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/dc/dsc/rc_calc_dpi.c b/drivers/gpu/drm/amd/display/dc/dsc/rc_calc_dpi.c
index 381561ee0026..7e306aa3e2b9 100644
--- a/drivers/gpu/drm/amd/display/dc/dsc/rc_calc_dpi.c
+++ b/drivers/gpu/drm/amd/display/dc/dsc/rc_calc_dpi.c
@@ -100,6 +100,7 @@ int dscc_compute_dsc_parameters(const struct drm_dsc_config *pps, struct dsc_par
 	int              ret;
 	struct rc_params rc;
 	struct drm_dsc_config   dsc_cfg;
+	unsigned long long tmp;
 
 	calc_rc_params(&rc, pps);
 	dsc_params->pps = *pps;
@@ -111,9 +112,9 @@ int dscc_compute_dsc_parameters(const struct drm_dsc_config *pps, struct dsc_par
 	dsc_cfg.mux_word_size = dsc_params->pps.bits_per_component <= 10 ? 48 : 64;
 
 	ret = drm_dsc_compute_rc_parameters(&dsc_cfg);
-	dsc_params->bytes_per_pixel =
-			(uint32_t)(((unsigned long long)dsc_cfg.slice_chunk_size * 0x10000000 + (dsc_cfg.slice_width - 1))
-							/ (uint32_t)dsc_cfg.slice_width);  //ROUND-UP
+	tmp = (unsigned long long)dsc_cfg.slice_chunk_size * 0x10000000 + (dsc_cfg.slice_width - 1);
+	do_div(tmp, (uint32_t)dsc_cfg.slice_width);  //ROUND-UP
+	dsc_params->bytes_per_pixel = (uint32_t)tmp;
 
 	copy_pps_fields(&dsc_params->pps, &dsc_cfg);
 	dsc_params->rc_buffer_model_size = dsc_cfg.rc_bits;
-- 
2.31.1