From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934581AbcAZM1q (ORCPT ); Tue, 26 Jan 2016 07:27:46 -0500 Received: from szxga03-in.huawei.com ([119.145.14.66]:20716 "EHLO szxga03-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934226AbcAZM1l (ORCPT ); Tue, 26 Jan 2016 07:27:41 -0500 Message-ID: <56A76631.2070802@huawei.com> Date: Tue, 26 Jan 2016 20:27:29 +0800 From: Shannon Zhao User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:24.0) Gecko/20100101 Thunderbird/24.4.0 MIME-Version: 1.0 To: Stefano Stabellini CC: , , , , , , , , , , , , , , , Rob Herring Subject: Re: [PATCH v3 16/17] FDT: Add a helper to get specified name subnode References: <1453519184-11908-1-git-send-email-zhaoshenglong@huawei.com> <1453519184-11908-17-git-send-email-zhaoshenglong@huawei.com> In-Reply-To: Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.177.16.142] X-CFilter-Loop: Reflected X-Mirapoint-Virus-RAPID-Raw: score=unknown(0), refid=str=0001.0A090205.56A76638.00BE,ss=1,re=0.000,recu=0.000,reip=0.000,cl=1,cld=1,fgs=0, ip=0.0.0.0, so=2013-05-26 15:14:31, dmn=2013-03-21 17:37:32 X-Mirapoint-Loop-Id: a3fc1ab19205ce72b597fe4758c94e3b Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2016/1/26 20:11, Stefano Stabellini wrote: > On Sat, 23 Jan 2016, Shannon Zhao wrote: >> > From: Shannon Zhao >> > >> > Sometimes it needs to check if there is a node in FDT by full path. >> > Introduce this helper to get the specified name subnode if it exists. >> > >> > Signed-off-by: Shannon Zhao >> > --- >> > CC: Rob Herring >> > --- >> > drivers/of/fdt.c | 35 +++++++++++++++++++++++++++++++++++ >> > include/linux/of_fdt.h | 2 ++ >> > 2 files changed, 37 insertions(+) >> > >> > diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c >> > index 655f79d..112ec16 100644 >> > --- a/drivers/of/fdt.c >> > +++ b/drivers/of/fdt.c >> > @@ -645,6 +645,41 @@ int __init of_scan_flat_dt(int (*it)(unsigned long node, >> > } >> > >> > /** >> > + * of_get_flat_dt_subnode_by_name - get subnode of specified node by name >> > + * >> > + * @node: the parent node >> > + * @uname: the name of subnode >> > + * @return offset of the subnode, or -FDT_ERR_NOTFOUND if there is none >> > + */ >> > + >> > +int of_get_flat_dt_subnode_by_name(unsigned long node, const char *uname) >> > +{ >> > + const void *blob = initial_boot_params; >> > + int offset; >> > + const char *pathp; >> > + >> > + /* Find first subnode if it exists */ >> > + offset = fdt_first_subnode(blob, node); >> > + if (offset < 0) >> > + return -FDT_ERR_NOTFOUND; >> > + pathp = fdt_get_name(blob, offset, NULL); >> > + if (strncmp(pathp, uname, strlen(uname)) == 0) >> > + return offset; > Wouldn't this check succeed even if uname is "uefi" and the node > name is actually "uefiiiii"? You might have to use strcmp. > Ah, yes. Will fix this. > >> > + /* Find other subnodes */ >> > + do { >> > + offset = fdt_next_subnode(blob, offset); >> > + if (offset < 0) >> > + return -FDT_ERR_NOTFOUND; >> > + pathp = fdt_get_name(blob, offset, NULL); >> > + if (strncmp(pathp, uname, strlen(uname)) == 0) >> > + return offset; >> > + } while (offset >= 0); > Rather than writing the name check twice, I think it would be best to > code this loop as: > > for (offset = fdt_first_subnode(blob, offset); > offset >= 0; > offset = fdt_next_subnode(blob, offset)) { > > /* do name check */ > > > Thanks for your suggestion. Will change this. -- Shannon