From mboxrd@z Thu Jan 1 00:00:00 1970 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=-17.4 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,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 C84A3C2D0A3 for ; Fri, 6 Nov 2020 07:42:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 737D020867 for ; Fri, 6 Nov 2020 07:42:00 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="S1l2xLdT" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726545AbgKFHl7 (ORCPT ); Fri, 6 Nov 2020 02:41:59 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36326 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726497AbgKFHl6 (ORCPT ); Fri, 6 Nov 2020 02:41:58 -0500 Received: from mail-yb1-xb42.google.com (mail-yb1-xb42.google.com [IPv6:2607:f8b0:4864:20::b42]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5B08EC0613CF for ; Thu, 5 Nov 2020 23:41:57 -0800 (PST) Received: by mail-yb1-xb42.google.com with SMTP id m188so372204ybf.2 for ; Thu, 05 Nov 2020 23:41:57 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=QTZ+mR0yw2trxDGTFS+bvNciA6tk8BOqQlBiDGPQfJM=; b=S1l2xLdTqVq2ltEN2mrPy3XdtMyi05nRUV5f/FmPa9D60PlmPmlug2a8DGs5JByXUf U4hY1zdOfcNxVHh2+WK8ypBioWUs4WtfPRtJ4Fw4FqOB/D7VeyAcxDoGrxpa97MjEurH /D4RIRcbKxYD2wNBiDo4zRIVZDEjDYXKQC1gQTK/rvEArNqSbWlQNToz4GJotdfnyTat 4cWO/AcbXt8WJnt6F3Lu0s9yTyAMSIhvE1kMd4e3XbJcHUDTCHs8XULGSR7/TrbdADhC etr6br84kAkspmfqxlaF+5lFEhY3+pizLVdDIxHFAJ4I/DLa0GSn+bXgJiU7/lUFIK6K mB2A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=QTZ+mR0yw2trxDGTFS+bvNciA6tk8BOqQlBiDGPQfJM=; b=dHCps+Z2SrzS+mcfQoFWCb7ohl/GGA1Za2EXPYCMHK/N2HPQ7GzB7U4gVKcNVLzYc2 2uqUxIsgTw0i+dk53v2db8L/qzlr4pKI1SGCbmqlmzoQXpnVeyAydI/pzCru3kYIBQ76 0dk5cu6WhEKbUYier5k9O/n09/TvaetlWuh3rOOnhkSqPz6s9nQ7rqu3CbDP9dIw9jbx i2AQlwt9rsYclEd9cOBVlQ2NrN/FyOWXpXekuXprfEmD9Ab1KAxZAdeMYzfmIh6b3jCs ZzTc/1dhAxEocpWSjQDev2WhrAwnvfCaBR3dwAeLAl/g8RFJgzLUY7DKmtdeTOhx70Ch B+Cw== X-Gm-Message-State: AOAM533A/BTkAJTDxDShSWYnMqz/INXJx7yfbaHLaBXp5lWj7KbyIppJ xe0w2WbCfEeHJgbxvKRO7MkLQlwbsxKtYxRmupURYA== X-Google-Smtp-Source: ABdhPJwfrNAgvjm+h63iu1XRZnC29WoULOmr0mLAgXrY9MYEO6CcpB9pgsa2cDzepk0gfm2cOoTlaGnAT5Xyo+bmdOo= X-Received: by 2002:a25:1c86:: with SMTP id c128mr1143314ybc.96.1604648516320; Thu, 05 Nov 2020 23:41:56 -0800 (PST) MIME-Version: 1.0 References: <20201104232356.4038506-1-saravanak@google.com> <20201104232356.4038506-16-saravanak@google.com> <20201105094228.GE3439341@kroah.com> <20201106072247.GB2614221@kroah.com> In-Reply-To: <20201106072247.GB2614221@kroah.com> From: Saravana Kannan Date: Thu, 5 Nov 2020 23:41:20 -0800 Message-ID: Subject: Re: [PATCH v1 15/18] of: property: Update implementation of add_links() to create fwnode links To: Greg Kroah-Hartman Cc: "Rafael J. Wysocki" , "Rafael J. Wysocki" , Len Brown , Ard Biesheuvel , Rob Herring , Frank Rowand , Marc Zyngier , Thomas Gleixner , Tomi Valkeinen , Laurent Pinchart , Grygorii Strashko , Android Kernel Team , ACPI Devel Maling List , LKML , linux-efi , "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Nov 5, 2020 at 11:22 PM Greg Kroah-Hartman wrote: > > On Thu, Nov 05, 2020 at 03:25:56PM -0800, Saravana Kannan wrote: > > On Thu, Nov 5, 2020 at 1:41 AM Greg Kroah-Hartman > > wrote: > > > > > > On Wed, Nov 04, 2020 at 03:23:52PM -0800, Saravana Kannan wrote: > > > > The semantics of add_links() has changed from creating device link > > > > between devices to creating fwnode links between fwnodes. So, update the > > > > implementation of add_links() to match the new semantics. > > > > > > > > Signed-off-by: Saravana Kannan > > > > --- > > > > drivers/of/property.c | 150 ++++++++++++------------------------------ > > > > 1 file changed, 41 insertions(+), 109 deletions(-) > > > > > > > > diff --git a/drivers/of/property.c b/drivers/of/property.c > > > > index 408a7b5f06a9..86303803f1b3 100644 > > > > --- a/drivers/of/property.c > > > > +++ b/drivers/of/property.c > > > > @@ -1038,33 +1038,9 @@ static bool of_is_ancestor_of(struct device_node *test_ancestor, > > > > } > > > > > > > > /** > > > > - * of_get_next_parent_dev - Add device link to supplier from supplier phandle > > > > - * @np: device tree node > > > > - * > > > > - * Given a device tree node (@np), this function finds its closest ancestor > > > > - * device tree node that has a corresponding struct device. > > > > - * > > > > - * The caller of this function is expected to call put_device() on the returned > > > > - * device when they are done. > > > > - */ > > > > -static struct device *of_get_next_parent_dev(struct device_node *np) > > > > -{ > > > > - struct device *dev = NULL; > > > > - > > > > - of_node_get(np); > > > > - do { > > > > - np = of_get_next_parent(np); > > > > - if (np) > > > > - dev = get_dev_from_fwnode(&np->fwnode); > > > > - } while (np && !dev); > > > > - of_node_put(np); > > > > - return dev; > > > > -} > > > > - > > > > -/** > > > > - * of_link_to_phandle - Add device link to supplier from supplier phandle > > > > - * @dev: consumer device > > > > - * @sup_np: phandle to supplier device tree node > > > > + * of_link_to_phandle - Add fwnode link to supplier from supplier phandle > > > > + * @con_np: consumer device tree node > > > > + * @sup_np: supplier device tree node > > > > * > > > > * Given a phandle to a supplier device tree node (@sup_np), this function > > > > * finds the device that owns the supplier device tree node and creates a > > > > @@ -1074,16 +1050,14 @@ static struct device *of_get_next_parent_dev(struct device_node *np) > > > > * cases, it returns an error. > > > > * > > > > * Returns: > > > > - * - 0 if link successfully created to supplier > > > > - * - -EAGAIN if linking to the supplier should be reattempted > > > > + * - 0 if fwnode link successfully created to supplier > > > > * - -EINVAL if the supplier link is invalid and should not be created > > > > - * - -ENODEV if there is no device that corresponds to the supplier phandle > > > > + * - -ENODEV if struct device will never be create for supplier > > > > */ > > > > -static int of_link_to_phandle(struct device *dev, struct device_node *sup_np, > > > > - u32 dl_flags) > > > > +static int of_link_to_phandle(struct device_node *con_np, > > > > + struct device_node *sup_np) > > > > { > > > > - struct device *sup_dev, *sup_par_dev; > > > > - int ret = 0; > > > > + struct device *sup_dev; > > > > struct device_node *tmp_np = sup_np; > > > > > > > > of_node_get(sup_np); > > > > @@ -1106,7 +1080,8 @@ static int of_link_to_phandle(struct device *dev, struct device_node *sup_np, > > > > } > > > > > > > > if (!sup_np) { > > > > - dev_dbg(dev, "Not linking to %pOFP - No device\n", tmp_np); > > > > + pr_debug("Not linking %pOFP to %pOFP - No device\n", > > > > + con_np, tmp_np); > > > > > > Who is calling this function without a valid dev pointer? > > > > Sorry, I plan to delete the "dev" parameter as it's not really used > > anywhere. I'm trying to do that without causing build time errors and > > making the series into digestible small patches. > > > > I can do the deletion of the parameter as a Patch 19/19. Will that work? > > That's fine, but why get rid of dev? The driver core works on these > things, and we want errors/messages/warnings to spit out what device is > causing those issues. It is fine to drag around a struct device pointer > just for messages, that's to be expected, and is good. In general I agree. If the fwnode being parsed is related to the dev, it's nice to have the dev name in the logs. But in this instance I feel it's analogous to printing the PID that's parsing the fwnode -- kinda irrelevant. The device in question can appear very random and it'll just cause more confusion than be of help if it shows up in the logs. For example it can be something like: : linking to If the device was actually that of the wifi fwnode of the iommu fwnode, I agree it'll be useful to carry around the dev even if it's just for logs. Hope that makes sense. > > > And the only way it can be NULL is if fwnode is NULL, and as you control > > > the callers to it, how can that be the case? > > > > fwnode represents a generic firmware node. The to_of_node() returns > > NULL if fwnode is not a DT node. So con_np can be NULL if that > > happens. That's why we need a NULL check here. With the current code, > > that can never happen, bit I think it doesn't hurt to check in case > > there's a buggy caller. I don't have a strong opinion - so I can do it > > whichever way. > > If it can't happen, no need to check for it :) I don't have a strong opinion, so I can delete it if you insist. -Saravana