linux-kernel - [PATCH] media: platform: synopsys: hdmirx: Fix 64-bit division for 32-bit targets

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Message-Id: <20250306-synopsys-hdmirx-fix-64-div-v1-1-dd5ff38bba5e@kernel.org>
Date: Thu, 06 Mar 2025 22:45:16 +0100
From: Nathan Chancellor <nathan@...nel.org>
To: Shreeya Patel <shreeya.patel@...labora.com>, 
 Mauro Carvalho Chehab <mchehab@...nel.org>, 
 Dmitry Osipenko <dmitry.osipenko@...labora.com>, 
 Hans Verkuil <hverkuil@...all.nl>
Cc: linux-media@...r.kernel.org, kernel@...labora.com, 
 linux-kernel@...r.kernel.org, Nathan Chancellor <nathan@...nel.org>
Subject: [PATCH] media: platform: synopsys: hdmirx: Fix 64-bit division for
 32-bit targets

The build fails for 32-bit targets with:

  arm-linux-gnueabi-ld: drivers/media/platform/synopsys/hdmirx/snps_hdmirx.o: in function `hdmirx_get_timings':
  snps_hdmirx.c:(.text.hdmirx_get_timings+0x46c): undefined reference to `__aeabi_uldivmod'

bt->pixelclock is __u64, which causes the compiler to emit a libcall for
64-bit division. Use the optimized kernel helper, div_u64(), to resolve
this.

Fixes: 7b59b132ad43 ("media: platform: synopsys: Add support for HDMI input driver")
Signed-off-by: Nathan Chancellor <nathan@...nel.org>
---
 drivers/media/platform/synopsys/hdmirx/snps_hdmirx.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/media/platform/synopsys/hdmirx/snps_hdmirx.c b/drivers/media/platform/synopsys/hdmirx/snps_hdmirx.c
index 4d42da7255f3..e4cdd8b5745d 100644
--- a/drivers/media/platform/synopsys/hdmirx/snps_hdmirx.c
+++ b/drivers/media/platform/synopsys/hdmirx/snps_hdmirx.c
@@ -17,6 +17,7 @@
 #include <linux/interrupt.h>
 #include <linux/irq.h>
 #include <linux/mfd/syscon.h>
+#include <linux/math64.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_platform.h>
@@ -291,7 +292,7 @@ static void hdmirx_get_timings(struct snps_hdmirx_dev *hdmirx_dev,
 	hfp = htotal - hact - hs - hbp;
 	vfp = vtotal - vact - vs - vbp;
 
-	fps = (bt->pixelclock + (htotal * vtotal) / 2) / (htotal * vtotal);
+	fps = div_u64(bt->pixelclock + (htotal * vtotal) / 2, htotal * vtotal);
 	bt->width = hact;
 	bt->height = vact;
 	bt->hfrontporch = hfp;

---
base-commit: 143d75583f2427f3a97dba62413c4f0604867ebf
change-id: 20250306-synopsys-hdmirx-fix-64-div-c014c102bf48

Best regards,
-- 
Nathan Chancellor <nathan@...nel.org>