From nobody Fri Dec 19 20:38:13 2025 Received: from smtp1.tecnico.ulisboa.pt (smtp1.tecnico.ulisboa.pt [193.136.128.21]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 507CE272E56; Thu, 4 Dec 2025 21:37:05 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=193.136.128.21 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764884228; cv=none; b=jNPGM2lpKwHCXFZSfaM7rh49qhGnq4Exne/vdbQ7mqOgGivSRzit3BSEPvLRuT+QnHs6zaxPg8VP13RbFO1gzShvV5or+BFg+Utryy6l7xpMPNi6wNwhDmYFf7+ICnDLWlvAWrmX0TZEMeoz5X2R56V72dxLkorhKBFBeZhtZZ0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764884228; c=relaxed/simple; bh=xf9W8khExmmglhR6CvPAqUspKha+T1FNlzX8AdCnkQg=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=lNZixVaW/0PIUA4uYeRDtT+0FK3ux/59ZfyrSa2Qe2/19eFalkDrUfh2UQJATkbdTjYSJ5ePlzEhm0/pMbFyCuCE8z3sCzpUXukwpR7Z/g2hzm/iAQvJpwl2DsX5RtIudsBOX+rba9R46+Mb7H6KLXAbOhbfdpbTL4FVlqDl8UQ= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=tecnico.ulisboa.pt; spf=pass smtp.mailfrom=tecnico.ulisboa.pt; dkim=pass (2048-bit key) header.d=tecnico.ulisboa.pt header.i=@tecnico.ulisboa.pt header.b=TK9PQ+fq; arc=none smtp.client-ip=193.136.128.21 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=tecnico.ulisboa.pt Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=tecnico.ulisboa.pt Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=tecnico.ulisboa.pt header.i=@tecnico.ulisboa.pt header.b="TK9PQ+fq" Received: from localhost (localhost.localdomain [127.0.0.1]) by smtp1.tecnico.ulisboa.pt (Postfix) with ESMTP id 93A0C6007C12; Thu, 4 Dec 2025 21:27:30 +0000 (WET) X-Virus-Scanned: by amavis-2.13.0 (20230106) (Debian) at tecnico.ulisboa.pt Received: from smtp1.tecnico.ulisboa.pt ([127.0.0.1]) by localhost (smtp1.tecnico.ulisboa.pt [127.0.0.1]) (amavis, port 10025) with LMTP id r-KcAZ9WELtN; Thu, 4 Dec 2025 21:27:28 +0000 (WET) Received: from mail1.tecnico.ulisboa.pt (mail1.ist.utl.pt [193.136.128.10]) by smtp1.tecnico.ulisboa.pt (Postfix) with ESMTPS id 285216007C27; Thu, 4 Dec 2025 21:27:26 +0000 (WET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=tecnico.ulisboa.pt; s=mail2; t=1764883646; 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: in-reply-to:in-reply-to:references:references; bh=gws7bqKRyNKCnBdDeWO44Ug9p/AFQeyiuCwnVQuZ3wk=; b=TK9PQ+fqy2nXv1tk7PhT4zhyVoHMNwKwQHm2sl5asqJWaSlpZI96R11Q8p4SAx+/lZsWVL TvcrelBK7FtCGqJ5aEDCtzTwcmromNjXWP7XHrmmnGUc4VlytBigoVvMWcORtrtSWoiZ+P UDQ5uaxhzD8ugS7o3vfuLweqCVviyb2cfqVT0mABJ+RFV4OoePuBb8Vh1jmmuJV/0GS8Bt ytYSist3DiXaO0leJbS8MjXWUs48W0BHXu2/Q8B4kby4jvFj6XRDD03NCSdLMlu4g9Yd/e HX4o1tsnccODznC2ZJoFIyS55u86kmusyg6CvVPNHiv9pzHJlfSgmOyPuJZB2Q== Received: from [192.168.1.151] (unknown [IPv6:2001:8a0:57db:f00:3ee2:38aa:e2c9:7dde]) (Authenticated sender: ist187313) by mail1.tecnico.ulisboa.pt (Postfix) with ESMTPSA id 001E836013C; Thu, 4 Dec 2025 21:27:25 +0000 (WET) From: Diogo Ivo Date: Thu, 04 Dec 2025 21:27:19 +0000 Subject: [PATCH 3/5] phy: tegra: xusb: Fix ordering issue when switching roles on USB2 ports Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20251204-diogo-tegra_phy-v1-3-51a2016d0be8@tecnico.ulisboa.pt> References: <20251204-diogo-tegra_phy-v1-0-51a2016d0be8@tecnico.ulisboa.pt> In-Reply-To: <20251204-diogo-tegra_phy-v1-0-51a2016d0be8@tecnico.ulisboa.pt> To: Mathias Nyman , Greg Kroah-Hartman , Thierry Reding , Jonathan Hunter , JC Kuo , Vinod Koul , Kishon Vijay Abraham I , Rob Herring , Krzysztof Kozlowski , Conor Dooley Cc: linux-usb@vger.kernel.org, linux-tegra@vger.kernel.org, linux-kernel@vger.kernel.org, linux-phy@lists.infradead.org, devicetree@vger.kernel.org, Diogo Ivo X-Mailer: b4 0.14.3 X-Developer-Signature: v=1; a=ed25519-sha256; t=1764883644; l=4982; i=diogo.ivo@tecnico.ulisboa.pt; s=20240529; h=from:subject:message-id; bh=xf9W8khExmmglhR6CvPAqUspKha+T1FNlzX8AdCnkQg=; b=aQSppPE/K65eVVqVi1Ey+4rSDItbToDQShSiE2nBqNvkn3KPbsWhZVXUa9fVOUzkdsXDnS/Xd ygSs1457/IIC6VfJjPQFWDkQiKxUn++DiE89U/n761OxxibJyW4ousi X-Developer-Key: i=diogo.ivo@tecnico.ulisboa.pt; a=ed25519; pk=BRGXhMh1q5KDlZ9y2B8SodFFY8FGupal+NMtJPwRpUQ= The current implementation of USB2 role switching on Tegra relies on whichever the previous USB controller driver was using the PHY to first "yield" it back to USB_ROLE_NONE before the next controller configures it for the new role. However, no mechanism to guarantee this ordering was implemented, and currently, in the general case, the configuration functions tegra_xhci_id_work() and tegra_xudc_usb_role_sw_work() end up running in the same order regardless of the transition being HOST->DEVICE or DEVICE->HOST, leading to one of these transitions ending up in a non-working state due to the new configuration being clobbered by the previous controller driver setting USB_ROLE_NONE after the fact. Fix this by introducing a helper that waits for the USB2 port=E2=80=99s cur= rent role to become USB_ROLE_NONE and add it in the configuration functions above before setting the role to either USB_ROLE_HOST or USB_ROLE_DEVICE. The specific parameters of the helper function are choices that seem reasonable in my testing and have no other basis. This was tested on a Tegra210 platform (Smaug). However, due to the similar approach in Tegra186 it is likely that not only this problem exists there but that this patch also fixes it. Signed-off-by: Diogo Ivo --- drivers/phy/tegra/xusb.c | 23 +++++++++++++++++++++++ drivers/usb/gadget/udc/tegra-xudc.c | 4 ++++ drivers/usb/host/xhci-tegra.c | 15 ++++++++++----- include/linux/phy/tegra/xusb.h | 1 + 4 files changed, 38 insertions(+), 5 deletions(-) diff --git a/drivers/phy/tegra/xusb.c b/drivers/phy/tegra/xusb.c index c89df95aa6ca..e05c3f2d1421 100644 --- a/drivers/phy/tegra/xusb.c +++ b/drivers/phy/tegra/xusb.c @@ -740,6 +740,29 @@ static void tegra_xusb_parse_usb_role_default_mode(str= uct tegra_xusb_port *port) } } =20 +bool tegra_xusb_usb2_port_wait_role_none(struct tegra_xusb_padctl *padctl,= int index) +{ + struct tegra_xusb_usb2_port *usb2 =3D tegra_xusb_find_usb2_port(padctl, + index); + int retries =3D 5; + + if (!usb2) { + dev_err(&usb2->base.dev, "no port found for USB2 lane %u\n", index); + return false; + } + + do { + if (usb2->role =3D=3D USB_ROLE_NONE) + return true; + + usleep_range(50, 60); + } while (retries--); + + dev_err(&usb2->base.dev, "timed out waiting for USB_ROLE_NONE"); + + return false; +} + static int tegra_xusb_usb2_port_parse_dt(struct tegra_xusb_usb2_port *usb2) { struct tegra_xusb_port *port =3D &usb2->base; diff --git a/drivers/usb/gadget/udc/tegra-xudc.c b/drivers/usb/gadget/udc/t= egra-xudc.c index 0c38fc37b6e6..72d725659e5f 100644 --- a/drivers/usb/gadget/udc/tegra-xudc.c +++ b/drivers/usb/gadget/udc/tegra-xudc.c @@ -698,8 +698,12 @@ static void tegra_xudc_restore_port_speed(struct tegra= _xudc *xudc) =20 static void tegra_xudc_device_mode_on(struct tegra_xudc *xudc) { + int port =3D tegra_xusb_padctl_get_port_number(xudc->curr_utmi_phy); int err; =20 + if (!tegra_xusb_usb2_port_wait_role_none(xudc->padctl, port)) + return; + pm_runtime_get_sync(xudc->dev); =20 tegra_phy_xusb_utmi_pad_power_on(xudc->curr_utmi_phy); diff --git a/drivers/usb/host/xhci-tegra.c b/drivers/usb/host/xhci-tegra.c index 9c69fccdc6e8..9944593166a3 100644 --- a/drivers/usb/host/xhci-tegra.c +++ b/drivers/usb/host/xhci-tegra.c @@ -1352,18 +1352,23 @@ static void tegra_xhci_id_work(struct work_struct *= work) struct tegra_xusb_mbox_msg msg; struct phy *phy =3D tegra_xusb_get_phy(tegra, "usb2", tegra->otg_usb2_port); + enum usb_role role =3D USB_ROLE_NONE; u32 status; int ret; =20 dev_dbg(tegra->dev, "host mode %s\n", str_on_off(tegra->host_mode)); =20 - mutex_lock(&tegra->lock); =20 - if (tegra->host_mode) - phy_set_mode_ext(phy, PHY_MODE_USB_OTG, USB_ROLE_HOST); - else - phy_set_mode_ext(phy, PHY_MODE_USB_OTG, USB_ROLE_NONE); + if (tegra->host_mode) { + if (!tegra_xusb_usb2_port_wait_role_none(tegra->padctl, + tegra->otg_usb2_port)) + return; =20 + role =3D USB_ROLE_HOST; + } + + mutex_lock(&tegra->lock); + phy_set_mode_ext(phy, PHY_MODE_USB_OTG, role); mutex_unlock(&tegra->lock); =20 tegra->otg_usb3_port =3D tegra_xusb_padctl_get_usb3_companion(tegra->padc= tl, diff --git a/include/linux/phy/tegra/xusb.h b/include/linux/phy/tegra/xusb.h index 6ca51e0080ec..a0d3d5b7cf33 100644 --- a/include/linux/phy/tegra/xusb.h +++ b/include/linux/phy/tegra/xusb.h @@ -33,5 +33,6 @@ int tegra_xusb_padctl_disable_phy_sleepwalk(struct tegra_= xusb_padctl *padctl, st int tegra_xusb_padctl_enable_phy_wake(struct tegra_xusb_padctl *padctl, st= ruct phy *phy); int tegra_xusb_padctl_disable_phy_wake(struct tegra_xusb_padctl *padctl, s= truct phy *phy); bool tegra_xusb_padctl_remote_wake_detected(struct tegra_xusb_padctl *padc= tl, struct phy *phy); +bool tegra_xusb_usb2_port_wait_role_none(struct tegra_xusb_padctl *padctl,= int index); =20 #endif /* PHY_TEGRA_XUSB_H */ --=20 2.52.0