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=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS autolearn=ham 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 6E293C43381 for ; Thu, 28 Mar 2019 19:24:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 473422173C for ; Thu, 28 Mar 2019 19:24:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726729AbfC1TYF (ORCPT ); Thu, 28 Mar 2019 15:24:05 -0400 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:50582 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726045AbfC1TYC (ORCPT ); Thu, 28 Mar 2019 15:24:02 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 8E17715AB; Thu, 28 Mar 2019 12:24:02 -0700 (PDT) Received: from [10.37.12.85] (unknown [10.37.12.85]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 3248A3F614; Thu, 28 Mar 2019 12:24:00 -0700 (PDT) Subject: Re: [PATCH v3 2/2] coresight: funnel: Support static funnel To: leo.yan@linaro.org, mathieu.poirier@linaro.org, robh+dt@kernel.org, mark.rutland@arm.com, alexander.shishkin@linux.intel.com, linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, coresight@lists.linaro.org, shiwanglai@hisilicon.com References: <20190328023509.22242-1-leo.yan@linaro.org> <20190328023509.22242-3-leo.yan@linaro.org> From: Suzuki K Poulose Message-ID: <799f3f27-6a20-836e-b699-252ebb8e2fdf@arm.com> Date: Thu, 28 Mar 2019 19:26:16 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 MIME-Version: 1.0 In-Reply-To: <20190328023509.22242-3-leo.yan@linaro.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 03/28/2019 02:35 AM, Leo Yan wrote: > Since CoreSight hardware topology can use a 'hidden' funnel in the > trace data path, this kind funnel doesn't have register for accessing > and is used by default from hardware design perspective. Below is an > example for related hardware topology: > > +------+ +------+ > | cpu0 |->| ETM |-\ > +------+ +------+ \-> +--------+ +-----+ > ...... | Funnel |->| ETF |-\ Hidden funnel > +------+ +------+ /-> +--------+ +-----+ \ | > | cpu3 |->| ETM |-/ \ V > +------+ +------+ \-> +--------+ > | Funnel |-> ... > +------+ +------+ /-> +--------+ > | cpu4 |->| ETM |-\ / > +------+ +------+ \-> +--------+ +-----+ / > ...... | Funnel |->| ETF |-/ > +------+ +------+ /-> +--------+ +-----+ > | cpu7 |->| ETM |-/ > +------+ +------+ > > The CoreSight funnel driver only supports dynamic funnel with > registration register resource, thus it cannot support for the static > funnel case and it's impossible to create trace data path for this case. > > This patch is to extend CoreSight funnel driver to support both for > static funnel and dynamic funnel. For the dynamic funnel it reuses the > code existed in the driver, for static funnel the driver will support > device probe if without providing register resource and the driver skips > registers accessing when detect the register base is NULL. > > Cc: Mathieu Poirier > Cc: Suzuki K Poulose > Cc: Wanglai Shi > Suggested-by: Suzuki K Poulose > Signed-off-by: Leo Yan Reviewed-by: Suzuki K Poulose