linux-kernel - [PATCH 1/2] arm64: dts: amlogic: s4: assign mmc b clock to 24MHz

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: <20260113-amlogic-s4-mmc-fixup-v1-1-1ab1fca0fb2f@baylibre.com>
Date: Tue, 13 Jan 2026 11:39:52 +0100
From: Jerome Brunet <jbrunet@...libre.com>
To: Rob Herring <robh@...nel.org>, Krzysztof Kozlowski <krzk+dt@...nel.org>, 
 Conor Dooley <conor+dt@...nel.org>, 
 Neil Armstrong <neil.armstrong@...aro.org>, 
 Kevin Hilman <khilman@...libre.com>, 
 Martin Blumenstingl <martin.blumenstingl@...glemail.com>, 
 Xianwei Zhao <xianwei.zhao@...ogic.com>, Nick Xie <nick@...das.com>
Cc: devicetree@...r.kernel.org, linux-arm-kernel@...ts.infradead.org, 
 linux-amlogic@...ts.infradead.org, linux-kernel@...r.kernel.org, 
 Jerome Brunet <jbrunet@...libre.com>
Subject: [PATCH 1/2] arm64: dts: amlogic: s4: assign mmc b clock to 24MHz

The amlogic MMC operate with the assumption that MMC clock
is configured to provide 24MHz. It uses that path for low
rates such as 400kHz.

This assumption did hold true until but it now, but it apparently
not the case with s4. The clock has been reported to provide 1GHz
instead. This is most likely due to how the bootloader is using the MMC
clock on this platform.

Regardless of why the MMC clock is set to 1GHz, if the MMC driver expects
24MHz, we should make sure it does get that, so assign the clock.

Reported-by: Nick Xie <nick@...das.com>
Closes: https://lore.kernel.org/linux-amlogic/20260113011931.40424-1-nick@khadas.com/
Fixes: 3ab9d54b5d84 ("arm64: dts: amlogic: enable some device nodes for S4")
Signed-off-by: Jerome Brunet <jbrunet@...libre.com>
---
 arch/arm64/boot/dts/amlogic/meson-s4.dtsi | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/arm64/boot/dts/amlogic/meson-s4.dtsi b/arch/arm64/boot/dts/amlogic/meson-s4.dtsi
index 9d99ed2994dfa27ca5808da7ae0825e9af255417..62538fd9db6b1ffb33a88e12628aadefbaa453ec 100644
--- a/arch/arm64/boot/dts/amlogic/meson-s4.dtsi
+++ b/arch/arm64/boot/dts/amlogic/meson-s4.dtsi
@@ -838,6 +838,10 @@ sd: mmc@...8a000 {
 			clock-names = "core", "clkin0", "clkin1";
 			resets = <&reset RESET_SD_EMMC_B>;
 			status = "disabled";
+
+			assigned-clocks = <&clkc_periphs CLKID_SD_EMMC_B>;
+			assigned-clock-parents = <0>;
+			assigned-clock-rates = <24000000>;
 		};
 
 		emmc: mmc@...8c000 {

-- 
2.47.3