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=-2.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,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 5965DC3A5A2 for ; Fri, 23 Aug 2019 15:42:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 22CC221726 for ; Fri, 23 Aug 2019 15:42:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1566574975; bh=Ti+JFOxtfY4aFLAmYLp1w1FeV/K8JqmsfuLfsVrrcss=; h=Subject:To:Cc:References:From:Date:In-Reply-To:List-ID:From; b=rIsZVJSShHA0JloUnY9yHQ+mDvfSFX4F0PgKJZkiQi4ZJ2KhkkT9HXc5vHW8L9I0x V2+hBbl5CNCQQAF/XOfnKx4/v/P5nB90D/DXgiZDu7WkPPWnI9DyjAdg1n5RX5b32L wtQhkDT/Tr6KDQOvLF+UPNCe969VQavetrOnaOuA= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726840AbfHWPmy (ORCPT ); Fri, 23 Aug 2019 11:42:54 -0400 Received: from mail.kernel.org ([198.145.29.99]:55428 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726465AbfHWPmx (ORCPT ); Fri, 23 Aug 2019 11:42:53 -0400 Received: from [192.168.1.17] (cpe-70-114-128-244.austin.res.rr.com [70.114.128.244]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id C7F0921019; Fri, 23 Aug 2019 15:42:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1566574971; bh=Ti+JFOxtfY4aFLAmYLp1w1FeV/K8JqmsfuLfsVrrcss=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=TLbaSaipgAn8VLEbJtX7oJgIeHcwllCXA+Aap2GSIb10sj07/Yu3uTutSS/9CLi56 IWLR2hMxTw2xV/g87fog6WNu+s6qz2+rAKWTFpx/VLjrhC9efE3sk+u6CnLqmZnASq JGV3uGaxUVVZYq1x9LRjb3+8InFDDxuK4T0r180s= Subject: Re: [RESEND PATCHv4 1/1] drivers/amba: add reset control to amba bus probe To: Linus Walleij , Philipp Zabel Cc: "linux-kernel@vger.kernel.org" , "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" , Rob Herring , Russell King , Frank Rowand , Kees Cook , Anton Vorontsov , Colin Cross , Tony Luck , Daniel Thompson , Manivannan Sadhasivam , Linux ARM References: <20190820145834.7301-1-dinguyen@kernel.org> <20190820145834.7301-2-dinguyen@kernel.org> From: Dinh Nguyen Openpgp: preference=signencrypt Autocrypt: addr=dinguyen@kernel.org; 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Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 8/23/19 4:19 AM, Linus Walleij wrote: > On Tue, Aug 20, 2019 at 4:58 PM Dinh Nguyen wrote: > >> @@ -401,6 +402,26 @@ static int amba_device_try_add(struct amba_device *dev, struct resource *parent) >> ret = amba_get_enable_pclk(dev); >> if (ret == 0) { >> u32 pid, cid; >> + int count; >> + struct reset_control *rstc; >> + >> + /* >> + * Find reset control(s) of the amba bus and de-assert them. >> + */ >> + count = reset_control_get_count(&dev->dev); >> + while (count > 0) { >> + rstc = of_reset_control_get_shared_by_index(dev->dev.of_node, count - 1); >> + if (IS_ERR(rstc)) { >> + if (PTR_ERR(rstc) == -EPROBE_DEFER) >> + ret = -EPROBE_DEFER; >> + else >> + dev_err(&dev->dev, "Can't get amba reset!\n"); >> + break; >> + } >> + reset_control_deassert(rstc); >> + reset_control_put(rstc); >> + count--; >> + } > > I'm not normally a footprint person, but the looks of the stubs in > makes me suspicious whether this will have zero impact > in size on platforms without reset controllers. > > Can you just ls -al on the kernel without CONFIG_RESET_CONTROLLER > before and after this patch and ascertain that it has zero footprint effect? Thanks for the review. I checked it, and indeed, it does have a zero footprint effect. > > If it doesn't I'd sure like to break this into its own function and > stick a if (!IS_ENABLED(CONFIG_RESET_CONTROLLER)) return 0; > in there to make sure the compiler drops it. > > Also it'd be nice to get Philipp's ACK on the semantics, though they > look correct to me. > Dinh