From patchwork Thu Jun 1 23:55:30 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Roy Luo X-Patchwork-Id: 13264598 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 CE5DDC7EE29 for ; Thu, 1 Jun 2023 23:55:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232870AbjFAXzt (ORCPT ); Thu, 1 Jun 2023 19:55:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47460 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229800AbjFAXzs (ORCPT ); Thu, 1 Jun 2023 19:55:48 -0400 Received: from mail-vs1-xe49.google.com (mail-vs1-xe49.google.com [IPv6:2607:f8b0:4864:20::e49]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C468518D for ; Thu, 1 Jun 2023 16:55:46 -0700 (PDT) Received: by mail-vs1-xe49.google.com with SMTP id ada2fe7eead31-437e7ec4b7cso474934137.1 for ; Thu, 01 Jun 2023 16:55:46 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1685663746; x=1688255746; h=cc:to:from:subject:message-id:mime-version:date:from:to:cc:subject :date:message-id:reply-to; bh=UJkB69k3ZxWDepJQL271GwWrwJ3qj8faMRIhiHLNDpo=; b=Ra727GF8yuTMCnLgCZ5fayzKoV2j6jqJKfG2IUUx7AW8PjbRd5VJ7RTVSs089vQntK UTtVI/r/41vTaCiKbKTH9gAgA7oncoS9qTbeU00f9nBDEtSvnRzwyC5OP43qoKUq2mfB dYuBpnpVG9G7Sq+Rz6LSk4Zui45GWB1SZLDXWNrGlyTF3Lgui5ECdUe6HiHV6a+h3GKc IIKQgJ/CKC30QD7mnEhH6ypoP698d3nT4o5sZ450+yQnYmWTVrHNu4ysEFcar3P0EXi7 S8FwLhTVdsah23DAReHOXW7E6cKIA3bZKRSP6obSDftf8enM1ezdn7kGXhA9uzqCBsDn UcQw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1685663746; x=1688255746; h=cc:to:from:subject:message-id:mime-version:date:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=UJkB69k3ZxWDepJQL271GwWrwJ3qj8faMRIhiHLNDpo=; b=lojJ5LHxnHjcibWFAZRv7XYYvSyAPaZs2ML+Cfa3geMd8YvhJIPiAvCg+Uizy4GG+h IajClmIhB2P0i490HmH+vTdq1QCMTnWeNTh6Vu39ayJdwWt+RNLPxCwrag7nfQeQs866 b44lLoBbKE+36iNzf3+/RapLLL8532P9YLsvUqVrQypzMK6pzPFluiUUQBnRA3cKgo0P voYDpfNWuaXjjrWegRpHTO4btd+jf6AQk5JU9EK9fpwm2S10FzkuBd8toXCTs8hqMCKS WDaaP8sg80Nlgv+cP4FYzuPvikLYrh5FQgAqm56QAu3UcgYKPeJFCbDPQIKeYzo6HmL2 jq1A== X-Gm-Message-State: AC+VfDwvTGkR6MLityerhHoSy7N1MGlQQCuMBj6uNhTsO1j7W6e0ja9S X0s8hROoZqHsZoX3p1j/ZA18Cnh5jX0= X-Google-Smtp-Source: ACHHUZ7qGvhw9nny39+6ehIPLExFJrncwVbv/ck8lCkT6uaCaTxCeES8xf09jevIK8AZyMF9iKm+9hJPQd4= X-Received: from royluo-cloudtop0.c.googlers.com ([fda3:e722:ac3:cc00:14:4d90:c0a8:bb8]) (user=royluo job=sendgmr) by 2002:a67:d391:0:b0:439:30c7:d0d with SMTP id b17-20020a67d391000000b0043930c70d0dmr5767925vsj.3.1685663745921; Thu, 01 Jun 2023 16:55:45 -0700 (PDT) Date: Thu, 1 Jun 2023 23:55:30 +0000 Mime-Version: 1.0 X-Mailer: git-send-email 2.41.0.rc0.172.g3f132b7071-goog Message-ID: <20230601235531.2285354-1-royluo@google.com> Subject: [PATCH v2] usb: core: add sysfs entry for usb device state From: Roy Luo To: raychi@google.com, badhri@google.com, Greg Kroah-Hartman , Alan Stern , Benjamin Tissoires , Michael Grzeschik , Bastien Nocera , Mathias Nyman , Matthias Kaehlcke , Flavio Suligoi , Douglas Anderson , Christophe JAILLET Cc: linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org, Roy Luo Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org Expose usb device state to userland as the information is useful in detecting non-compliant setups and diagnosing enumeration failures. For example: - End-to-end signal integrity issues: the device would fail port reset repeatedly and thus be stuck in POWERED state. - Charge-only cables (missing D+/D- lines): the device would never enter POWERED state as the HC would not see any pullup. What's the status quo? We do have error logs such as "Cannot enable. Maybe the USB cable is bad?" to flag potential setup issues, but there's no good way to expose them to userspace. Why add a sysfs entry in struct usb_port instead of struct usb_device? The struct usb_device is not device_add() to the system until it's in ADDRESS state hence we would miss the first two states. The struct usb_port is a better place to keep the information because its life cycle is longer than the struct usb_device that is attached to the port. Reviewed-by: Alan Stern Signed-off-by: Roy Luo --- This patch comes directly from RFC v2 after being reviewed by Alan Stern Link: https://lore.kernel.org/all/20230531010134.1092942-1-royluo@google.com/ More discussion about implementation options is in RFC v1 Link: https://lore.kernel.org/all/20230525173818.219633-1-royluo@google.com/ Changes since v1: * Address Alan Stern's comment: remove redundant NULL initializers in update_port_device_state(). --- Documentation/ABI/testing/sysfs-bus-usb | 9 +++++++++ drivers/usb/core/hub.c | 19 +++++++++++++++++++ drivers/usb/core/hub.h | 2 ++ drivers/usb/core/port.c | 11 +++++++++++ 4 files changed, 41 insertions(+) base-commit: 933174ae28ba72ab8de5b35cb7c98fc211235096 diff --git a/Documentation/ABI/testing/sysfs-bus-usb b/Documentation/ABI/testing/sysfs-bus-usb index cb172db41b34..155770f18f9c 100644 --- a/Documentation/ABI/testing/sysfs-bus-usb +++ b/Documentation/ABI/testing/sysfs-bus-usb @@ -292,6 +292,15 @@ Description: which is marked with early_stop has failed to initialize, it will ignore all future connections until this attribute is clear. +What: /sys/bus/usb/devices/...//port/state +Date: May 2023 +Contact: Roy Luo +Description: + Indicates current state of the USB device attached to the port. Valid + states are: 'not-attached', 'attached', 'powered', + 'reconnecting', 'unauthenticated', 'default', 'addressed', + 'configured', and 'suspended'. + What: /sys/bus/usb/devices/.../power/usb2_lpm_l1_timeout Date: May 2013 Contact: Mathias Nyman diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c index 97a0f8faea6e..d6bc5622e45e 100644 --- a/drivers/usb/core/hub.c +++ b/drivers/usb/core/hub.c @@ -2018,6 +2018,23 @@ bool usb_device_is_owned(struct usb_device *udev) return !!hub->ports[udev->portnum - 1]->port_owner; } +static void update_port_device_state(struct usb_device *udev) +{ + struct usb_hub *hub; + struct usb_port *port_dev; + struct kernfs_node *state_node; + + if (udev->parent) { + hub = usb_hub_to_struct_hub(udev->parent); + port_dev = hub->ports[udev->portnum - 1]; + WRITE_ONCE(port_dev->state, udev->state); + state_node = sysfs_get_dirent(port_dev->dev.kobj.sd, "state"); + if (state_node) { + sysfs_notify_dirent(state_node); + } + } +} + static void recursively_mark_NOTATTACHED(struct usb_device *udev) { struct usb_hub *hub = usb_hub_to_struct_hub(udev); @@ -2030,6 +2047,7 @@ static void recursively_mark_NOTATTACHED(struct usb_device *udev) if (udev->state == USB_STATE_SUSPENDED) udev->active_duration -= jiffies; udev->state = USB_STATE_NOTATTACHED; + update_port_device_state(udev); } /** @@ -2086,6 +2104,7 @@ void usb_set_device_state(struct usb_device *udev, udev->state != USB_STATE_SUSPENDED) udev->active_duration += jiffies; udev->state = new_state; + update_port_device_state(udev); } else recursively_mark_NOTATTACHED(udev); spin_unlock_irqrestore(&device_state_lock, flags); diff --git a/drivers/usb/core/hub.h b/drivers/usb/core/hub.h index e23833562e4f..cd13fe189726 100644 --- a/drivers/usb/core/hub.h +++ b/drivers/usb/core/hub.h @@ -84,6 +84,7 @@ struct usb_hub { * @peer: related usb2 and usb3 ports (share the same connector) * @req: default pm qos request for hubs without port power control * @connect_type: port's connect type + * @state: device state of the usb device attached to the port * @location: opaque representation of platform connector location * @status_lock: synchronize port_event() vs usb_port_{suspend|resume} * @portnum: port index num based one @@ -100,6 +101,7 @@ struct usb_port { struct usb_port *peer; struct dev_pm_qos_request *req; enum usb_port_connect_type connect_type; + enum usb_device_state state; usb_port_location_t location; struct mutex status_lock; u32 over_current_count; diff --git a/drivers/usb/core/port.c b/drivers/usb/core/port.c index 06a8f1f84f6f..745f2a3aafba 100644 --- a/drivers/usb/core/port.c +++ b/drivers/usb/core/port.c @@ -160,6 +160,16 @@ static ssize_t connect_type_show(struct device *dev, } static DEVICE_ATTR_RO(connect_type); +static ssize_t state_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct usb_port *port_dev = to_usb_port(dev); + enum usb_device_state state = READ_ONCE(port_dev->state); + + return sprintf(buf, "%s\n", usb_state_string(state)); +} +static DEVICE_ATTR_RO(state); + static ssize_t over_current_count_show(struct device *dev, struct device_attribute *attr, char *buf) { @@ -259,6 +269,7 @@ static DEVICE_ATTR_RW(usb3_lpm_permit); static struct attribute *port_dev_attrs[] = { &dev_attr_connect_type.attr, + &dev_attr_state.attr, &dev_attr_location.attr, &dev_attr_quirks.attr, &dev_attr_over_current_count.attr,