From patchwork Wed Apr 15 15:05:46 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nicolas Saenz Julienne X-Patchwork-Id: 201994 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=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT autolearn=ham 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 02620C2BA19 for ; Wed, 15 Apr 2020 15:06:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DC3262076A for ; Wed, 15 Apr 2020 15:06:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2394152AbgDOPGV (ORCPT ); Wed, 15 Apr 2020 11:06:21 -0400 Received: from mx2.suse.de ([195.135.220.15]:60680 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2394090AbgDOPGT (ORCPT ); Wed, 15 Apr 2020 11:06:19 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id C85A1AFBA; Wed, 15 Apr 2020 15:06:16 +0000 (UTC) From: Nicolas Saenz Julienne To: saravanak@google.com, Greg Kroah-Hartman , devicetree@vger.kernel.org, Rob Herring , Frank Rowand Cc: Nicolas Saenz Julienne , linux-kernel@vger.kernel.org Subject: [PATCH 1/4] of: property: Fix create device links for all child-supplier dependencies Date: Wed, 15 Apr 2020 17:05:46 +0200 Message-Id: <20200415150550.28156-2-nsaenzjulienne@suse.de> X-Mailer: git-send-email 2.26.0 In-Reply-To: <20200415150550.28156-1-nsaenzjulienne@suse.de> References: <20200415150550.28156-1-nsaenzjulienne@suse.de> MIME-Version: 1.0 Sender: devicetree-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org Upon adding a new platform device we scan its properties and its children's properties in order to create a consumer/supplier relationship between the device and the property supplier. That said, it's possible for some of the node's children to be disabled, which will create links that'll never be fulfilled. To get around this, use the for_each_available_child_of_node() function instead of for_each_available_node() when iterating over the node's children. Fixes: d4387cd11741 ("of: property: Create device links for all child-supplier depencencies") Signed-off-by: Nicolas Saenz Julienne --- drivers/of/property.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/of/property.c b/drivers/of/property.c index b4916dcc9e725..a8c2b13521b27 100644 --- a/drivers/of/property.c +++ b/drivers/of/property.c @@ -1296,7 +1296,7 @@ static int of_link_to_suppliers(struct device *dev, if (of_link_property(dev, con_np, p->name)) ret = -ENODEV; - for_each_child_of_node(con_np, child) + for_each_available_child_of_node(con_np, child) if (of_link_to_suppliers(dev, child) && !ret) ret = -EAGAIN; From patchwork Wed Apr 15 15:05:49 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nicolas Saenz Julienne X-Patchwork-Id: 201992 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=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT 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 E12ACC3815B for ; Wed, 15 Apr 2020 15:06:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C34A4208FE for ; Wed, 15 Apr 2020 15:06:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2394188AbgDOPGX (ORCPT ); Wed, 15 Apr 2020 11:06:23 -0400 Received: from mx2.suse.de ([195.135.220.15]:60738 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2394096AbgDOPGW (ORCPT ); Wed, 15 Apr 2020 11:06:22 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id BD32EAFBF; Wed, 15 Apr 2020 15:06:19 +0000 (UTC) From: Nicolas Saenz Julienne To: saravanak@google.com, Greg Kroah-Hartman , devicetree@vger.kernel.org, Rob Herring , Frank Rowand Cc: Nicolas Saenz Julienne , linux-kernel@vger.kernel.org Subject: [PATCH 4/4] of: property: Avoid linking devices with circular dependencies Date: Wed, 15 Apr 2020 17:05:49 +0200 Message-Id: <20200415150550.28156-5-nsaenzjulienne@suse.de> X-Mailer: git-send-email 2.26.0 In-Reply-To: <20200415150550.28156-1-nsaenzjulienne@suse.de> References: <20200415150550.28156-1-nsaenzjulienne@suse.de> MIME-Version: 1.0 Sender: devicetree-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org When creating a consumer/supplier relationship between devices it's essential to make sure they aren't supplying each other creating a circular dependency. Introduce a new function to check if such circular dependency exists between two device nodes and use it in of_link_to_phandle(). Fixes: a3e1d1a7f5fc ("of: property: Add functional dependency link from DT bindings") Signed-off-by: Nicolas Saenz Julienne --- NOTE: I feel of_link_is_circular() is a little dense, and could benefit from some abstraction/refactoring. That said, I'd rather get some feedback, before spending time on it. drivers/of/property.c | 50 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 50 insertions(+) diff --git a/drivers/of/property.c b/drivers/of/property.c index 2c7978ef22be1..74a5190408c3b 100644 --- a/drivers/of/property.c +++ b/drivers/of/property.c @@ -1171,6 +1171,44 @@ static const struct supplier_bindings of_supplier_bindings[] = { {} }; +/** + * of_link_is_circular - Make sure potential link isn't circular + * + * @sup_np: Supplier device + * @con_np: Consumer device + * + * This function checks if @sup_np's properties contain a reference to @con_np. + * + * Will return true if there's a circular dependency and false otherwise. + */ +static bool of_link_is_circular(struct device_node *sup_np, + struct device_node *con_np) +{ + const struct supplier_bindings *s = of_supplier_bindings; + struct device_node *tmp; + bool matched = false; + struct property *p; + int i = 0; + + for_each_property_of_node(sup_np, p) { + while (!matched && s->parse_prop) { + while ((tmp = s->parse_prop(sup_np, p->name, i))) { + matched = true; + i++; + + if (tmp == con_np) + return true; + } + i = 0; + s++; + } + s = of_supplier_bindings; + matched = false; + } + + return false; +} + /** * of_link_to_phandle - Add device link to supplier from supplier phandle * @dev: consumer device @@ -1216,6 +1254,18 @@ static int of_link_to_phandle(struct device *dev, struct device_node *sup_np, return -ENODEV; } + /* + * It is possible for consumer device nodes to also supply the device + * node they are consuming from. Creating an unwarranted circular + * dependency. + */ + if (of_link_is_circular(sup_np, dev->of_node)) { + dev_dbg(dev, "Not linking to %pOFP - Circular dependency\n", + sup_np); + of_node_put(sup_np); + return -ENODEV; + } + /* * Don't allow linking a device node as a consumer of one of its * descendant nodes. By definition, a child node can't be a functional