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=-5.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 CC3BAC433F2 for ; Thu, 23 Jul 2020 01:49:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B81F22080D for ; Thu, 23 Jul 2020 01:49:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387522AbgGWBtj (ORCPT ); Wed, 22 Jul 2020 21:49:39 -0400 Received: from regular1.263xmail.com ([211.150.70.201]:39588 "EHLO regular1.263xmail.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729198AbgGWBtj (ORCPT ); Wed, 22 Jul 2020 21:49:39 -0400 Received: from localhost (unknown [192.168.167.225]) by regular1.263xmail.com (Postfix) with ESMTP id D7FF0A54; Thu, 23 Jul 2020 09:49:36 +0800 (CST) X-MAIL-GRAY: 0 X-MAIL-DELIVERY: 1 X-ADDR-CHECKED4: 1 X-ANTISPAM-LEVEL: 2 X-SKE-CHECKED: 1 X-ABS-CHECKED: 1 Received: from [172.16.12.236] (unknown [58.22.7.114]) by smtp.263.net (postfix) whith ESMTP id P17824T139851630368512S1595468975533575_; Thu, 23 Jul 2020 09:49:36 +0800 (CST) X-IP-DOMAINF: 1 X-UNIQUE-TAG: <556b12a816981c0b51110575844fb20a> X-RL-SENDER: zhangqing@rock-chips.com X-SENDER: zhangqing@rock-chips.com X-LOGIN-NAME: zhangqing@rock-chips.com X-FST-TO: kever.yang@rock-chips.com X-SENDER-IP: 58.22.7.114 X-ATTACHMENT-NUM: 0 X-DNS-TYPE: 0 X-System-Flag: 0 Subject: Re: [PATCH v1] clk: Export __clk_lookup() From: "elaine.zhang" To: Stephen Boyd , Heiko Stuebner Cc: mturquette@baylibre.com, linux-clk@vger.kernel.org, linux-rockchip@lists.infradead.org, linux-kernel@vger.kernel.org, xxx@rock-chips.com, xf@rock-chips.com, huangtao@rock-chips.com, kever.yang@rock-chips.com References: <20200722023230.10826-1-zhangqing@rock-chips.com> <14639646.VOZsFJ8Tpa@phil> <159546549321.3847286.4678382117195983280@swboyd.mtv.corp.google.com> Organization: rockchip Message-ID: <99eebfa5-e775-37a8-6c76-90ae2444b253@rock-chips.com> Date: Thu, 23 Jul 2020 09:49:35 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US Sender: linux-clk-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-clk@vger.kernel.org 在 2020/7/23 上午9:42, elaine.zhang 写道: > > 在 2020/7/23 上午8:51, Stephen Boyd 写道: >> Quoting Heiko Stuebner (2020-07-22 11:26:50) >>> Hi Elaine, >>> >>> Am Mittwoch, 22. Juli 2020, 04:32:30 CEST schrieb Elaine Zhang: >>>> Export __clk_lookup() to support user built as module. >>>> >>>> ERROR: >>>> drivers/clk/rockchip/clk.ko: In function >>>> `rockchip_clk_protect_critical': >>>> drivers/clk/rockchip/clk.c:741: >>>> undefined reference to `__clk_lookup' >>> can you elaborate a bit more on why this would be needed? >>> >>> Because right now the Rockchip clocks are of course built into >>> the main kernel image (especially due to them being needed during early >>> boot) and __clk_lookup actually is a pretty deep part of the clock- >>> framework itself, as probably also denoted by the "__" in the function >>> name. >>> >> Can you stop using __clk_lookup()? The plan is to remove it. > > Rk use  __clk_lookup() as: > > drivers/clk/rockchip/clk.c > > void __init rockchip_clk_protect_critical(const char *const clocks[], >                                           int nclocks) > { >         int i; > >         /* Protect the clocks that needs to stay on */ >         for (i = 0; i < nclocks; i++) { >                 struct clk *clk = __clk_lookup(clocks[i]); > >                 if (clk) >                         clk_prepare_enable(clk); >         } > } > e.g: > > drivers/clk/rockchip/clk-rk3328.c > > static const char *const rk3328_critical_clocks[] __initconst = { >         "aclk_bus", >         "aclk_bus_niu", >         "pclk_bus", >         "pclk_bus_niu", >         "hclk_bus", >         "hclk_bus_niu", >         "aclk_peri", > ............ > > }; > > If have plan to remove the __clk_lookup, I need to replace the > rockchip_clk_protect_critical, and use the flag CLK_IS_CRITICAL.(but > use flag CLK_IS_CRITICAL, the enable count is always "0") Use the CLK_IS_CRITICAL, there is no guarantee that the parent clk is enabled, So the flag CLK_IS_CRITICAL need to be added to all special clks according to the clk tree. > >> >>