From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Fri, 09 Mar 2012 02:33:42 +0100 (CET) Received: from mail-iy0-f177.google.com ([209.85.210.177]:46589 "EHLO mail-iy0-f177.google.com" rhost-flags-OK-OK-OK-OK) by eddie.linux-mips.org with ESMTP id S1903692Ab2CIBdd (ORCPT ); Fri, 9 Mar 2012 02:33:33 +0100 Received: by iaky10 with SMTP id y10so1866009iak.36 for ; Thu, 08 Mar 2012 17:33:27 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20120113; h=sender:from:subject:to:cc:in-reply-to:references:date:message-id :x-gm-message-state; bh=w0rlf8839gitIxtqSw1lIosDGI82MZLGqFfeJaw73ck=; b=d4iDv+XFgZB8n+i4Zprf8GjaRalrulDguiEwI8vnInamXFg8H60OSq79ihdxZ+Z7Oq I30eAZl0zIONw1Ri+hB+RlzZXwp7SyX+wFo27uQXe9XAVlShAwMnobAXM8MdlF/nLKLg MH+20+VPk2V+9tWV6prUCnv5Hsyx5cvPoFUBbQQfa9qBDcTy+//wr4QtRWeeM8S5pYae 23UwLbC2nRtPt3lLhu6U5AeOl8eta61a0FymyTZzJSZib/phIftZ8R+k7asRh0/HXAi8 DxFT3ok1daJxqyw5sX4/xwpUoyYEAx+wdTOMaW+OOIqKi7qy0DdOMs5SmsBcJm1Yxvns Wdiw== Received: by 10.50.194.233 with SMTP id hz9mr27377igc.11.1331256806924; Thu, 08 Mar 2012 17:33:26 -0800 (PST) Received: from localhost (S0106d8b37715ee14.cg.shawcable.net. [68.146.14.168]) by mx.google.com with ESMTPS id pr8sm365115igb.6.2012.03.08.17.33.24 (version=TLSv1/SSLv3 cipher=OTHER); Thu, 08 Mar 2012 17:33:25 -0800 (PST) Received: by localhost (Postfix, from userid 1000) id 64DF53E0901; Thu, 8 Mar 2012 18:33:24 -0700 (MST) From: Grant Likely Subject: Re: [PATCH v6 2/2] of: Make of_find_node_by_path() traverse /aliases for relative paths. To: David Daney , linux-mips@linux-mips.org, ralf@linux-mips.org, devicetree-discuss@lists.ozlabs.org, Rob Herring Cc: linux-kernel@vger.kernel.org, David Daney In-Reply-To: <1330543264-18103-3-git-send-email-ddaney.cavm@gmail.com> References: <1330543264-18103-1-git-send-email-ddaney.cavm@gmail.com> <1330543264-18103-3-git-send-email-ddaney.cavm@gmail.com> Date: Thu, 08 Mar 2012 18:33:24 -0700 Message-Id: <20120309013324.64DF53E0901@localhost> X-Gm-Message-State: ALoCoQk2FWc2wsBkoCwGB23aCj4G7Fs6c17+BZ+wRxUoAi7SdSEVa0hdL0kmsj0epJhIuWyXIN3b X-archive-position: 32621 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: grant.likely@secretlab.ca Precedence: bulk X-list: linux-mips Return-Path: On Wed, 29 Feb 2012 11:21:04 -0800, David Daney wrote: > From: David Daney > > Currently all paths passed to of_find_node_by_path() must begin with a > '/', indicating a full path to the desired node. > > Augment the look-up code so that if a path does *not* begin with '/', > the path is used as the name of an /aliases property. The value of > this alias is then used as the full node path to be found. > > Signed-off-by: David Daney > --- > drivers/of/base.c | 65 ++++++++++++++++++++++++++++++++++++++++++++++++++-- > 1 files changed, 62 insertions(+), 3 deletions(-) > > diff --git a/drivers/of/base.c b/drivers/of/base.c > index 5806449..0bbe47c 100644 > --- a/drivers/of/base.c > +++ b/drivers/of/base.c > @@ -365,22 +365,81 @@ EXPORT_SYMBOL(of_get_next_child); > > /** > * of_find_node_by_path - Find a node matching a full OF path > - * @path: The full path to match > + * @path: Either the full path to match, or if the path does not > + * start with '/', the name of a property of the /aliases > + * node (an alias). In the case of an alias, the node > + * matching the alias' value will be returned. > * > * Returns a node pointer with refcount incremented, use > * of_node_put() on it when done. > */ > struct device_node *of_find_node_by_path(const char *path) > { > - struct device_node *np = allnodes; > + struct device_node *np = NULL; > + struct device_node *aliases = NULL; > + char *alias = NULL; > + char *new_path = NULL; > + char *ps; > > read_lock(&devtree_lock); > - for (; np; np = np->allnext) { > + > + /* > + * The following code has three possibilities: > + * 1) '/' at start of string; path == ps; (based at root) > + * 2) '/' at offset in string; path < ps; (relative to alias) > + * 3) '/' not found; ps == NULL; (alias only) > + * > + * If ps != path, then it is either a pure alias (ps == NULL), > + * or an alias with a relative path (path < ps). Either way, > + * look up the path pointed to by the alias. > + */ > + ps = strchr(path, '/'); > + if (path != ps) { > + aliases = of_find_node_by_path("/aliases"); > + if (!aliases) > + goto out; > + > + /* > + * Duplicate the alias part of the string so it can be > + * NULL terminated. > + */ > + alias = kstrndup(path, > + ps ? (ps - path) : strlen(path), GFP_KERNEL); > + if (!alias) > + goto out; > + path = of_get_property(aliases, alias, NULL); > + if (!path || path[0] != '/') > + goto out; All the aliases are already decoded at boot time now. See of_alias_scan(). Instead of open-coding this, you can add an of_alias_lookup() function something like this (untested): const char *of_alias_lookup(const char *alias) { struct alias_prop *app; list_for_each_entry(app, &aliases_lookup, link) { if (strcmp(app->alias, alias)) return app->np->full_name; } return NULL; } Then most of the above code disappears. It can instead look like: ps = strchr(path, '/'); if (path != ps) { char alias[ps - path + 1]; strncpy(alias, path, ps - path); alias[ps - path] = '\0'; path = of_alias_lookup(alias); if (path && ps) /* Don't forget to free this */ path = kasprintf(GFP_KERNEL, "%s%s", path, ps); if (!path) return NULL; } g. > + > + /* If ps is not NULL, then there is a relative path to append */ > + if (ps) { > + new_path = kzalloc(strlen(path) + strlen(ps) + 1, > + GFP_KERNEL); > + if (!new_path) > + goto out; > + > + sprintf(new_path, "%s%s", path, ps); > + path = new_path; > + } > + } > + > + /* > + * At this point, path now points to the full unaliased path > + * to a node, regardless of whether or not it started with an > + * alias. > + */ > + > + for (np = allnodes; np; np = np->allnext) { > if (np->full_name && (of_node_cmp(np->full_name, path) == 0) > && of_node_get(np)) > break; > } > +out: > + if (aliases) > + of_node_put(aliases); > read_unlock(&devtree_lock); > + kfree(alias); > + kfree(new_path); > return np; > } > EXPORT_SYMBOL(of_find_node_by_path); > -- > 1.7.2.3 > -- email sent from notmuch.vim plugin