From nobody Wed Dec 17 20:39:45 2025 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 98B4DC61D98 for ; Tue, 21 Nov 2023 22:11:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234329AbjKUWLH (ORCPT ); Tue, 21 Nov 2023 17:11:07 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38730 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234313AbjKUWLC (ORCPT ); Tue, 21 Nov 2023 17:11:02 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1F7D6194 for ; Tue, 21 Nov 2023 14:10:59 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1700604658; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=gdwjKLBCPHbhmKdp+NaAgsF4FPxnedN47CRRapavUMU=; b=P8n8hB8XASfj9wNNqBMB+G4g/Kj+C9KpOgYZ+Fm7o2VTPe3rPbZk24eM0osJK2SOICIc+N 5gSgRUKTSZLJSKsHBYe4mMa/+6cw1LAhMuVKr3slh3/X3iS31KJnKTBZ4roc/wD+3X1y90 PpZjYnT4R4xd+qif+QqUmLoqOXECn/g= Received: from mail-yb1-f199.google.com (mail-yb1-f199.google.com [209.85.219.199]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-263-kGY4MumHOveW-lvnKMNNHg-1; Tue, 21 Nov 2023 17:10:57 -0500 X-MC-Unique: kGY4MumHOveW-lvnKMNNHg-1 Received: by mail-yb1-f199.google.com with SMTP id 3f1490d57ef6-da03390793fso7400888276.3 for ; Tue, 21 Nov 2023 14:10:56 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1700604656; x=1701209456; h=cc:to:message-id:content-transfer-encoding:mime-version:subject :date:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=gdwjKLBCPHbhmKdp+NaAgsF4FPxnedN47CRRapavUMU=; b=PvdbXTySzsXI/iswX75bHblPL6KntzlpCrPJPDiVAbJDt/1ksLW0B5hqAFBZVXRAJK HYDcmW3kL+UEWTSz/uknKzQWP2Lf0lQO9qsFYFIphSa1vkCd4R4Bg731oAsNp20tKY+G jIZaPjRnXChVg54TohWKYPNYW6PpQ5d/XPYCOwwOKsXGpMBJ/Ei79gSigpLvw8hnG/iZ SIx4AXYmoFc6gwk8Ih03xDhXQG2aXw+xYRC0d9VwA1YiSc6OqHYcDk7a59pJDJsQ33wh LJ7OzoxMrM8+Vko1N8kUmNHJmvLGwa0QWUQ7nU9voolXJV62imkSg0JNPLXkxSSSL33i 8btQ== X-Gm-Message-State: AOJu0YzjqA5Tn+QjAaNwwA5TW4Prm+eGRIbQ2SpbNg6VgdB+IKJtAUga dYMxYICOeNADsdAqYg0TzQM2/+bk+gCQFz7J/3RUBzA6d8vQ8d8URVzF1H940ZxBThKAXoOp7bH iv5vx0ITBlPpC/3UYZUxo5hoH X-Received: by 2002:a25:6a42:0:b0:daf:936f:4547 with SMTP id f63-20020a256a42000000b00daf936f4547mr324092ybc.19.1700604656380; Tue, 21 Nov 2023 14:10:56 -0800 (PST) X-Google-Smtp-Source: AGHT+IFE090DqFilJY7Grpyrn6Z8VnqvMejJY8JbukGhhcycTVKzgxbz8+AeQIpmf/uCRmVju8tO5Q== X-Received: by 2002:a25:6a42:0:b0:daf:936f:4547 with SMTP id f63-20020a256a42000000b00daf936f4547mr324079ybc.19.1700604656021; Tue, 21 Nov 2023 14:10:56 -0800 (PST) Received: from [192.168.1.165] ([2600:1700:1ff0:d0e0::37]) by smtp.gmail.com with ESMTPSA id c19-20020a056214071300b00670fd658739sm4321099qvz.38.2023.11.21.14.10.55 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 21 Nov 2023 14:10:55 -0800 (PST) From: Andrew Halaney Date: Tue, 21 Nov 2023 16:10:37 -0600 Subject: [PATCH net-next] net: phy: mdio_device: Reset device only when necessary MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20231121-net-phy-reset-once-v1-1-37c960b6336c@redhat.com> X-B4-Tracking: v=1; b=H4sIANwqXWUC/x2MQQ6DMAwEvxL5jCXsXNp+BXFAdAFfDEpQlQrl7 025zUize1FGMmR6hYsSPpZt9ybSBZq3yVewvZuT9hpFVNhx8rF9OSE32n0GCzRqfD50Qk9teCQ sVu7Tgf69o5w01voDrFYUdW4AAAA= To: Andrew Lunn , Heiner Kallweit , Russell King , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Sagar Cheluvegowda , Andrew Halaney X-Mailer: b4 0.12.3 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Currently the phy reset sequence is as shown below for a devicetree described mdio phy on boot: 1. Assert the phy_device's reset as part of registering 2. Deassert the phy_device's reset as part of registering 3. Deassert the phy_device's reset as part of phy_probe 4. Deassert the phy_device's reset as part of phy_hw_init The extra two deasserts include waiting the deassert delay afterwards, which is adding unnecessary delay. Here's some snipped tracing output using the following command line params "trace_event=3Dgpio:* trace_options=3Dstacktrace" illustrating the reset handling and where its coming from: /* Assert */ systemd-udevd-283 [002] ..... 6.780434: gpio_value: 544 set 0 systemd-udevd-283 [002] ..... 6.783849: =3D> gpiod_set_raw_value_commit =3D> gpiod_set_value_nocheck =3D> gpiod_set_value_cansleep =3D> mdio_device_reset =3D> mdiobus_register_device =3D> phy_device_register =3D> fwnode_mdiobus_phy_device_register =3D> fwnode_mdiobus_register_phy =3D> __of_mdiobus_register =3D> stmmac_mdio_register =3D> stmmac_dvr_probe =3D> stmmac_pltfr_probe =3D> devm_stmmac_pltfr_probe =3D> qcom_ethqos_probe =3D> platform_probe /* Deassert */ systemd-udevd-283 [002] ..... 6.802480: gpio_value: 544 set 1 systemd-udevd-283 [002] ..... 6.805886: =3D> gpiod_set_raw_value_commit =3D> gpiod_set_value_nocheck =3D> gpiod_set_value_cansleep =3D> mdio_device_reset =3D> phy_device_register =3D> fwnode_mdiobus_phy_device_register =3D> fwnode_mdiobus_register_phy =3D> __of_mdiobus_register =3D> stmmac_mdio_register =3D> stmmac_dvr_probe =3D> stmmac_pltfr_probe =3D> devm_stmmac_pltfr_probe =3D> qcom_ethqos_probe =3D> platform_probe /* Deassert */ systemd-udevd-283 [002] ..... 6.882601: gpio_value: 544 set 1 systemd-udevd-283 [002] ..... 6.886014: =3D> gpiod_set_raw_value_commit =3D> gpiod_set_value_nocheck =3D> gpiod_set_value_cansleep =3D> mdio_device_reset =3D> phy_probe =3D> really_probe =3D> __driver_probe_device =3D> driver_probe_device =3D> __device_attach_driver =3D> bus_for_each_drv =3D> __device_attach =3D> device_initial_probe =3D> bus_probe_device =3D> device_add =3D> phy_device_register =3D> fwnode_mdiobus_phy_device_register =3D> fwnode_mdiobus_register_phy =3D> __of_mdiobus_register =3D> stmmac_mdio_register =3D> stmmac_dvr_probe =3D> stmmac_pltfr_probe =3D> devm_stmmac_pltfr_probe =3D> qcom_ethqos_probe =3D> platform_probe /* Deassert */ NetworkManager-477 [000] ..... 7.023144: gpio_value: 544 set 1 NetworkManager-477 [000] ..... 7.026596: =3D> gpiod_set_raw_value_commit =3D> gpiod_set_value_nocheck =3D> gpiod_set_value_cansleep =3D> mdio_device_reset =3D> phy_init_hw =3D> phy_attach_direct =3D> phylink_fwnode_phy_connect =3D> __stmmac_open =3D> stmmac_open There's a lot of paths where the device is getting its reset asserted and deasserted. Let's track the state and only actually do the assert/deassert when it changes. Reported-by: Sagar Cheluvegowda Signed-off-by: Andrew Halaney --- This patch isn't the prettiest thing in the world, but the myriad of call paths that lead to touching the reset gpio is proving daunting to me. I originally tried to remove some of the reset calls in various places, but after staring at the different call paths I decided this was safer, I am not confident I covered all the corner cases when going about this by removing the extra phy_device_reset/mdio_device_reset calls. --- drivers/net/phy/mdio_device.c | 5 +++++ include/linux/mdio.h | 1 + 2 files changed, 6 insertions(+) diff --git a/drivers/net/phy/mdio_device.c b/drivers/net/phy/mdio_device.c index 044828d081d2..d2b9e62edaaa 100644 --- a/drivers/net/phy/mdio_device.c +++ b/drivers/net/phy/mdio_device.c @@ -122,6 +122,9 @@ void mdio_device_reset(struct mdio_device *mdiodev, int= value) if (!mdiodev->reset_gpio && !mdiodev->reset_ctrl) return; =20 + if (mdiodev->reset_state =3D=3D value) + return; + if (mdiodev->reset_gpio) gpiod_set_value_cansleep(mdiodev->reset_gpio, value); =20 @@ -135,6 +138,8 @@ void mdio_device_reset(struct mdio_device *mdiodev, int= value) d =3D value ? mdiodev->reset_assert_delay : mdiodev->reset_deassert_delay; if (d) fsleep(d); + + mdiodev->reset_state =3D value; } EXPORT_SYMBOL(mdio_device_reset); =20 diff --git a/include/linux/mdio.h b/include/linux/mdio.h index 007fd9c3e4b6..79ceee3c8673 100644 --- a/include/linux/mdio.h +++ b/include/linux/mdio.h @@ -38,6 +38,7 @@ struct mdio_device { /* Bus address of the MDIO device (0-31) */ int addr; int flags; + int reset_state; struct gpio_desc *reset_gpio; struct reset_control *reset_ctrl; unsigned int reset_assert_delay; --- base-commit: 07b677953b9dca02928be323e2db853511305fa9 change-id: 20231121-net-phy-reset-once-1e2323982ae0 Best regards, --=20 Andrew Halaney