linux-kernel - [PATCH v2] arm64: dts: imx8mp: use correct clock for eqos timestamping counter

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-next>] [day] [month] [year] [list]

Message-Id: <20230719-imx8mp_enet_qos_use_125mhz_clock-v2-1-eed15d74bfd1@pengutronix.de>
Date:   Fri, 21 Jul 2023 05:51:48 +0200
From:   Johannes Zink <j.zink@...gutronix.de>
To:     Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Conor Dooley <conor+dt@...nel.org>,
        Shawn Guo <shawnguo@...nel.org>,
        Sascha Hauer <s.hauer@...gutronix.de>,
        Pengutronix Kernel Team <kernel@...gutronix.de>,
        Fabio Estevam <festevam@...il.com>,
        NXP Linux Team <linux-imx@....com>
Cc:     patchwork-jzi@...gutronix.de, devicetree@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        Johannes Zink <j.zink@...gutronix.de>
Subject: [PATCH v2] arm64: dts: imx8mp: use correct clock for eqos
 timestamping counter

The i.MX8MP Reference Manual rev 1 06/2021, section 11.7.2.5 "Timestamp
Support" indicates the PTP timestamp clock expects a typical frequency
of 125MHz.

As this also improves the precision of the measured timestamps: assign
appropriate 125MHz Clock parent. As no one except the timestamping
counter uses this clock, there are no side-effects of this change in
other peripherals.

Signed-off-by: Johannes Zink <j.zink@...gutronix.de>
---
Changes in v2:
- not only set assigned-clock-parents but alkso assigned-clock-rates for
  IMX8MP_CLK_ENET_QOS_TIMER to 125MHz (found by Fabio's review -
  thanks!)
- Link to v1: https://lore.kernel.org/r/20230719-imx8mp_enet_qos_use_125mhz_clock-v1-1-782c9ac6e121@pengutronix.de
---
Changes:
  v1 -> v2: Worked in Fabio's Feedback - Thank you for your review!
             - not only set assigned clock parent to 125MHz but also
	       set the assigned clock rate of IMX8MP_CLK_ENET_QOS_TIMER
	       to 125MHz
---
 arch/arm64/boot/dts/freescale/imx8mp.dtsi | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/boot/dts/freescale/imx8mp.dtsi b/arch/arm64/boot/dts/freescale/imx8mp.dtsi
index 6f2f50e1639c..84ecf07affb3 100644
--- a/arch/arm64/boot/dts/freescale/imx8mp.dtsi
+++ b/arch/arm64/boot/dts/freescale/imx8mp.dtsi
@@ -1334,9 +1334,9 @@ eqos: ethernet@...f0000 {
 						  <&clk IMX8MP_CLK_ENET_QOS_TIMER>,
 						  <&clk IMX8MP_CLK_ENET_QOS>;
 				assigned-clock-parents = <&clk IMX8MP_SYS_PLL1_266M>,
-							 <&clk IMX8MP_SYS_PLL2_100M>,
+							 <&clk IMX8MP_SYS_PLL2_125M>,
 							 <&clk IMX8MP_SYS_PLL2_125M>;
-				assigned-clock-rates = <0>, <100000000>, <125000000>;
+				assigned-clock-rates = <0>, <125000000>, <125000000>;
 				nvmem-cells = <&eth_mac2>;
 				nvmem-cell-names = "mac-address";
 				intf_mode = <&gpr 0x4>;

---
base-commit: ba345b77fae7054d0cbd033283c47033e45db6d8
change-id: 20230719-imx8mp_enet_qos_use_125mhz_clock-1c4611c979ba

Best regards,
-- 
Johannes Zink <j.zink@...gutronix.de>