linux-kernel - [PATCH v6 4/7] drm/bridge: fsl-ldb: Use clk_round

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20241112100547.2908497-5-victor.liu@nxp.com>
Date: Tue, 12 Nov 2024 18:05:44 +0800
From: Liu Ying <victor.liu@....com>
To: imx@...ts.linux.dev,
	linux-arm-kernel@...ts.infradead.org,
	devicetree@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	linux-clk@...r.kernel.org,
	dri-devel@...ts.freedesktop.org
Cc: shawnguo@...nel.org,
	s.hauer@...gutronix.de,
	kernel@...gutronix.de,
	festevam@...il.com,
	robh@...nel.org,
	krzk+dt@...nel.org,
	conor+dt@...nel.org,
	catalin.marinas@....com,
	will@...nel.org,
	abelvesa@...nel.org,
	peng.fan@....com,
	mturquette@...libre.com,
	sboyd@...nel.org,
	andrzej.hajda@...el.com,
	neil.armstrong@...aro.org,
	rfoss@...nel.org,
	Laurent.pinchart@...asonboard.com,
	jonas@...boo.se,
	jernej.skrabec@...il.com,
	maarten.lankhorst@...ux.intel.com,
	mripard@...nel.org,
	tzimmermann@...e.de,
	airlied@...il.com,
	simona@...ll.ch,
	quic_bjorande@...cinc.com,
	geert+renesas@...der.be,
	dmitry.baryshkov@...aro.org,
	arnd@...db.de,
	nfraprado@...labora.com,
	marex@...x.de
Subject: [PATCH v6 4/7] drm/bridge: fsl-ldb: Use clk_round_rate() to validate "ldb" clock rate

Multiple display modes could be read from a display device's EDID.
Use clk_round_rate() to validate the "ldb" clock rate for each mode
in drm_bridge_funcs::mode_valid() to filter unsupported modes out.

Signed-off-by: Liu Ying <victor.liu@....com>
---
Note that this patch depends on a patch in shawnguo/imx/fixes:
https://patchwork.kernel.org/project/linux-arm-kernel/patch/20241017031146.157996-1-marex@denx.de/

v6:
* Drop pixel clock rate validation.

v5:
* No change.

v4:
* No change.

v3:
* No change.

v2:
* Add more comments in fsl-ldb.c and commit message about pixel clock
  rate validation.  (Maxime)

 drivers/gpu/drm/bridge/fsl-ldb.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/gpu/drm/bridge/fsl-ldb.c b/drivers/gpu/drm/bridge/fsl-ldb.c
index b559f3e0bef6..d9436ff9ccc3 100644
--- a/drivers/gpu/drm/bridge/fsl-ldb.c
+++ b/drivers/gpu/drm/bridge/fsl-ldb.c
@@ -270,10 +270,16 @@ fsl_ldb_mode_valid(struct drm_bridge *bridge,
 		   const struct drm_display_mode *mode)
 {
 	struct fsl_ldb *fsl_ldb = to_fsl_ldb(bridge);
+	unsigned long link_freq;
 
 	if (mode->clock > (fsl_ldb_is_dual(fsl_ldb) ? 160000 : 80000))
 		return MODE_CLOCK_HIGH;
 
+	/* Validate "ldb" clock rate. */
+	link_freq = fsl_ldb_link_frequency(fsl_ldb, mode->clock);
+	if (link_freq != clk_round_rate(fsl_ldb->clk, link_freq))
+		return MODE_NOCLOCK;
+
 	return MODE_OK;
 }
 
-- 
2.34.1