From patchwork Wed Sep 15 17:09:38 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Saravana Kannan X-Patchwork-Id: 512776 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-26.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT, USER_IN_DEF_DKIM_WL autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id BCD48C433EF for ; Wed, 15 Sep 2021 17:09:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A280260E90 for ; Wed, 15 Sep 2021 17:09:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230423AbhIORLO (ORCPT ); Wed, 15 Sep 2021 13:11:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41194 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230264AbhIORLM (ORCPT ); Wed, 15 Sep 2021 13:11:12 -0400 Received: from mail-yb1-xb49.google.com (mail-yb1-xb49.google.com [IPv6:2607:f8b0:4864:20::b49]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0D4BBC061764 for ; Wed, 15 Sep 2021 10:09:53 -0700 (PDT) Received: by mail-yb1-xb49.google.com with SMTP id b84-20020a253457000000b0059e6b730d45so4528921yba.6 for ; Wed, 15 Sep 2021 10:09:53 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=2lJ0J4500ZYIhX1EYV/ZexmHeXs7PML1pzFGBHjPm2U=; b=nI3Ht9LVInk1Tm3cGHj65FkLZwg8om+aKaHWFC3J/iqkNimaavtGddierU0U/LNH2v 99P343QiRJrpY2aYxf2G+emGzD7pHJEz8hWTHXDkX//2G6QBCvR/DyVnepVITg44m05L QQgtoomCzoO9bxa5fEdFcGYLLg8oJKoferC6gSwkXg9mJInH2HADJScJbYBWP8LPre9k 0Vt4fQoAauE+bvxgXld+nvBTiQl2rdgsOfY9TT+/+54XCNsfE8J4ACkTV/cAJ3MOVbHf +vbj6S4wNwrHt84hDokzcoSzR2PqV4HgJGgITx86IIWI1fWASseP+bzk5LnH/THpXJ0i zhjQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=2lJ0J4500ZYIhX1EYV/ZexmHeXs7PML1pzFGBHjPm2U=; b=Rsf2vp/yRSEwxe7bo2SLI9OxRw2CAPvcCIiDaVc9yEx5mYcyEPFX11PdvjFfYMvvN1 ljuaVDr6Lp0SYz8Iem3dwH9GPhMTjWi+vmqO5j1tQAjch2rTKreKQeBxtDpyFQVWM3Sx NhGG2eL2+pbE7N92O0UjID+oDL7PWIlbsQfE+LqZjokPqgCjDjLbDHyBxExemmWcys7P /CySiO7HeMllsMftMAy+p9i8I0Lfqo7/9bDgDNXvRIWH0C73hMKY60ybxLvP9F3QzU+b XxTzjkbd+RoFRsxu8Z/siCHzwCQGkysk9y/9j/1rlEU5jSOeIVAZdxQJczTxMyrkFZR6 kBeA== X-Gm-Message-State: AOAM532e8Xf4xAwuZUgcgXWj7li0bjY2I546PfjtEuCM/8PYH5SqlCsA HMIpuz94lSL/Hm8ySQ7KHigE1VdwGH3WkWQ= X-Google-Smtp-Source: ABdhPJzajoUWYGw9XTDVj89C0KnB5ylhkI12ge/OdvhJfcN8kj38fwKy6OfgQ4NxRDOpj1WyMWcSbTnO/1Dq35I= X-Received: from saravanak.san.corp.google.com ([2620:15c:2d:3:16d1:ab0e:fc4a:b9b1]) (user=saravanak job=sendgmr) by 2002:a25:bacd:: with SMTP id a13mr1389689ybk.216.1631725792265; Wed, 15 Sep 2021 10:09:52 -0700 (PDT) Date: Wed, 15 Sep 2021 10:09:38 -0700 In-Reply-To: <20210915170940.617415-1-saravanak@google.com> Message-Id: <20210915170940.617415-3-saravanak@google.com> Mime-Version: 1.0 References: <20210915170940.617415-1-saravanak@google.com> X-Mailer: git-send-email 2.33.0.309.g3052b89438-goog Subject: [PATCH v3 2/3] driver core: fw_devlink: Add support for FWNODE_FLAG_NEEDS_CHILD_BOUND_ON_ADD From: Saravana Kannan To: Greg Kroah-Hartman , "Rafael J. Wysocki" , Andrew Lunn , Heiner Kallweit , Russell King , "David S. Miller" , Jakub Kicinski , Len Brown , Saravana Kannan Cc: Geert Uytterhoeven , Vladimir Oltean , kernel-team@android.com, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, linux-acpi@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org If a parent device is also a supplier to a child device, fw_devlink=on by design delays the probe() of the child device until the probe() of the parent finishes successfully. However, some drivers of such parent devices (where parent is also a supplier) expect the child device to finish probing successfully as soon as they are added using device_add() and before the probe() of the parent device has completed successfully. One example of such a case is discussed in the link mentioned below. Add a flag to make fw_devlink=on not enforce these supplier-consumer relationships, so these drivers can continue working. Link: https://lore.kernel.org/netdev/CAGETcx_uj0V4DChME-gy5HGKTYnxLBX=TH2rag29f_p=UcG+Tg@mail.gmail.com/ Fixes: ea718c699055 ("Revert "Revert "driver core: Set fw_devlink=on by default""") Signed-off-by: Saravana Kannan --- drivers/base/core.c | 19 +++++++++++++++++++ include/linux/fwnode.h | 11 ++++++++--- 2 files changed, 27 insertions(+), 3 deletions(-) diff --git a/drivers/base/core.c b/drivers/base/core.c index 316df6027093..21d4cb5d3767 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -1722,6 +1722,25 @@ static int fw_devlink_create_devlink(struct device *con, struct device *sup_dev; int ret = 0; + /* + * In some cases, a device P might also be a supplier to its child node + * C. However, this would defer the probe of C until the probe of P + * completes successfully. This is perfectly fine in the device driver + * model. device_add() doesn't guarantee probe completion of the device + * by the time it returns. + * + * However, there are a few drivers that assume C will finish probing + * as soon as it's added and before P finishes probing. So, we provide + * a flag to let fw_devlink know not to delay the probe of C until the + * probe of P completes successfully. + * + * When such a flag is set, we can't create device links where P is the + * supplier of C as that would delay the probe of C. + */ + if (sup_handle->flags & FWNODE_FLAG_NEEDS_CHILD_BOUND_ON_ADD && + fwnode_is_ancestor_of(sup_handle, con->fwnode)) + return -EINVAL; + sup_dev = get_dev_from_fwnode(sup_handle); if (sup_dev) { /* diff --git a/include/linux/fwnode.h b/include/linux/fwnode.h index 59828516ebaf..9f4ad719bfe3 100644 --- a/include/linux/fwnode.h +++ b/include/linux/fwnode.h @@ -22,10 +22,15 @@ struct device; * LINKS_ADDED: The fwnode has already be parsed to add fwnode links. * NOT_DEVICE: The fwnode will never be populated as a struct device. * INITIALIZED: The hardware corresponding to fwnode has been initialized. + * NEEDS_CHILD_BOUND_ON_ADD: For this fwnode/device to probe successfully, its + * driver needs its child devices to be bound with + * their respective drivers as soon as they are + * added. */ -#define FWNODE_FLAG_LINKS_ADDED BIT(0) -#define FWNODE_FLAG_NOT_DEVICE BIT(1) -#define FWNODE_FLAG_INITIALIZED BIT(2) +#define FWNODE_FLAG_LINKS_ADDED BIT(0) +#define FWNODE_FLAG_NOT_DEVICE BIT(1) +#define FWNODE_FLAG_INITIALIZED BIT(2) +#define FWNODE_FLAG_NEEDS_CHILD_BOUND_ON_ADD BIT(3) struct fwnode_handle { struct fwnode_handle *secondary;