From patchwork Tue Nov 21 22:10:37 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrew Halaney X-Patchwork-Id: 13463691 X-Patchwork-Delegate: kuba@kernel.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="P8n8hB8X" 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 37730D56 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-f197.google.com (mail-yb1-f197.google.com [209.85.219.197]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-263-6CEObMDtMtWuhs46pvhg0Q-1; Tue, 21 Nov 2023 17:10:57 -0500 X-MC-Unique: 6CEObMDtMtWuhs46pvhg0Q-1 Received: by mail-yb1-f197.google.com with SMTP id 3f1490d57ef6-da03ef6fc30so7421924276.0 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=m0gSr8VeO91aAMJJIJnZl/AXNxfQz6YdxX/s5gpSS26wVbpHjI7RT9I2SEtRV67mvF iDiRg+ExPoRTu7Ey7g0l1Kxg/bkOnky0ftj0n6mETfMTihqXpqzPcI0sD/QY6MJK004l 9AW0oSAjF5qpzAOslCnJ9+Bb9VR48GJ7Tp7oKGKe5s7ywrB8sWLI1MIOqfAcxjVot8Ej jNPuITTv6mq7Lk6Nz0lPJwNIUYs3ot1YwNwAklF6k6dRB6qlAY9eBDVci0vrlQBCKlGl itBqUng82lsMpOxaJWUmtXCuW3jwgQHimomE8zX0LzP+BFocJyTVfeBo6z8rhJXQa28M S9Vw== X-Gm-Message-State: AOJu0YxdJlA87AjKLFYmuvA5c0AABGmfjaBRdVyRz0adesvXHMVGoTz6 ErBIg+uYo+uXmIXsBQVCChr0xUI0pPH5LSuQTOamxO8+fJrvyrebDpp8Gm0XI3v6PK0AiTJrpfC 8ms436NNyVxhlqa6r X-Received: by 2002:a25:6a42:0:b0:daf:936f:4547 with SMTP id f63-20020a256a42000000b00daf936f4547mr324093ybc.19.1700604656381; 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 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 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 X-Patchwork-Delegate: kuba@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=gpio:* trace_options=stacktrace" 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: => gpiod_set_raw_value_commit => gpiod_set_value_nocheck => gpiod_set_value_cansleep => mdio_device_reset => mdiobus_register_device => phy_device_register => fwnode_mdiobus_phy_device_register => fwnode_mdiobus_register_phy => __of_mdiobus_register => stmmac_mdio_register => stmmac_dvr_probe => stmmac_pltfr_probe => devm_stmmac_pltfr_probe => qcom_ethqos_probe => platform_probe /* Deassert */ systemd-udevd-283 [002] ..... 6.802480: gpio_value: 544 set 1 systemd-udevd-283 [002] ..... 6.805886: => gpiod_set_raw_value_commit => gpiod_set_value_nocheck => gpiod_set_value_cansleep => mdio_device_reset => phy_device_register => fwnode_mdiobus_phy_device_register => fwnode_mdiobus_register_phy => __of_mdiobus_register => stmmac_mdio_register => stmmac_dvr_probe => stmmac_pltfr_probe => devm_stmmac_pltfr_probe => qcom_ethqos_probe => platform_probe /* Deassert */ systemd-udevd-283 [002] ..... 6.882601: gpio_value: 544 set 1 systemd-udevd-283 [002] ..... 6.886014: => gpiod_set_raw_value_commit => gpiod_set_value_nocheck => gpiod_set_value_cansleep => mdio_device_reset => phy_probe => really_probe => __driver_probe_device => driver_probe_device => __device_attach_driver => bus_for_each_drv => __device_attach => device_initial_probe => bus_probe_device => device_add => phy_device_register => fwnode_mdiobus_phy_device_register => fwnode_mdiobus_register_phy => __of_mdiobus_register => stmmac_mdio_register => stmmac_dvr_probe => stmmac_pltfr_probe => devm_stmmac_pltfr_probe => qcom_ethqos_probe => platform_probe /* Deassert */ NetworkManager-477 [000] ..... 7.023144: gpio_value: 544 set 1 NetworkManager-477 [000] ..... 7.026596: => gpiod_set_raw_value_commit => gpiod_set_value_nocheck => gpiod_set_value_cansleep => mdio_device_reset => phy_init_hw => phy_attach_direct => phylink_fwnode_phy_connect => __stmmac_open => 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(+) --- base-commit: 07b677953b9dca02928be323e2db853511305fa9 change-id: 20231121-net-phy-reset-once-1e2323982ae0 Best regards, 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; + if (mdiodev->reset_state == value) + return; + if (mdiodev->reset_gpio) gpiod_set_value_cansleep(mdiodev->reset_gpio, value); @@ -135,6 +138,8 @@ void mdio_device_reset(struct mdio_device *mdiodev, int value) d = value ? mdiodev->reset_assert_delay : mdiodev->reset_deassert_delay; if (d) fsleep(d); + + mdiodev->reset_state = value; } EXPORT_SYMBOL(mdio_device_reset); 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;