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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id AF42DC001DF for ; Thu, 3 Aug 2023 13:55:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235193AbjHCNzU (ORCPT ); Thu, 3 Aug 2023 09:55:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42458 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229576AbjHCNzS (ORCPT ); Thu, 3 Aug 2023 09:55:18 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 0F82B196 for ; Thu, 3 Aug 2023 06:55:17 -0700 (PDT) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 96F6D113E; Thu, 3 Aug 2023 06:55:59 -0700 (PDT) Received: from [10.1.197.1] (ewhatever.cambridge.arm.com [10.1.197.1]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 030653F5A1; Thu, 3 Aug 2023 06:55:14 -0700 (PDT) Message-ID: <3a9b34c0-f5cc-8d55-d5b7-813e400d7715@arm.com> Date: Thu, 3 Aug 2023 14:55:13 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.13.0 Subject: Re: [PATCH V3 3/4] coresight: trbe: Add a representative coresight_platform_data for TRBE To: Anshuman Khandual , linux-arm-kernel@lists.infradead.org Cc: Sami Mujawar , Catalin Marinas , Will Deacon , Mark Rutland , Mike Leach , Leo Yan , Alexander Shishkin , James Clark , coresight@lists.linaro.org, linux-kernel@vger.kernel.org References: <20230803055652.1322801-1-anshuman.khandual@arm.com> <20230803055652.1322801-4-anshuman.khandual@arm.com> Content-Language: en-US From: Suzuki K Poulose In-Reply-To: <20230803055652.1322801-4-anshuman.khandual@arm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 03/08/2023 06:56, Anshuman Khandual wrote: > TRBE coresight devices do not need regular connections information, as the > paths get built between all percpu source and their respective percpu sink > devices. Please refer 'commit 2cd87a7b293d ("coresight: core: Add support > for dedicated percpu sinks")' which added support for percpu sink devices. > > coresight_register() expect device connections via the platform_data. TRBE > devices do not have any graph connections and thus is empty. With upcoming > ACPI support for TRBE, we do not get a real acpi_device and thus > coresight_get_platform_dat() will end up in failures. Hence this allocates > a zeroed coresight_platform_data structure and assigns that back into the > device. > > Cc: Suzuki K Poulose > Cc: Mike Leach > Cc: Leo Yan > Cc: Alexander Shishkin > Cc: coresight@lists.linaro.org > Cc: linux-arm-kernel@lists.infradead.org > Cc: linux-kernel@vger.kernel.org > Signed-off-by: Anshuman Khandual > --- > drivers/hwtracing/coresight/coresight-trbe.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/drivers/hwtracing/coresight/coresight-trbe.c b/drivers/hwtracing/coresight/coresight-trbe.c > index 7720619909d6..e1d9d06e7725 100644 > --- a/drivers/hwtracing/coresight/coresight-trbe.c > +++ b/drivers/hwtracing/coresight/coresight-trbe.c > @@ -1494,9 +1494,9 @@ static int arm_trbe_device_probe(struct platform_device *pdev) > if (!drvdata) > return -ENOMEM; > > - pdata = coresight_get_platform_data(dev); > - if (IS_ERR(pdata)) > - return PTR_ERR(pdata); > + pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL); > + if (!pdata) > + return -ENOMEM; Please could you add a comment in here, on why we use a dummy platform data ? It is good to have documented it in the code too. Suzuki > > dev_set_drvdata(dev, drvdata); > dev->platform_data = pdata;