From mboxrd@z Thu Jan 1 00:00:00 1970 From: Suzuki.Poulose@arm.com (Suzuki K Poulose) Date: Wed, 27 Apr 2016 18:25:29 +0100 Subject: [PATCH V4 16/18] coresight: tmc: implementing TMC-ETF AUX space API In-Reply-To: References: <1461708634-6327-1-git-send-email-mathieu.poirier@linaro.org> <1461708634-6327-17-git-send-email-mathieu.poirier@linaro.org> <5720A0AF.9090107@arm.com> Message-ID: <5720F609.6030501@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 27/04/16 18:22, Mathieu Poirier wrote: > On 27 April 2016 at 05:21, Suzuki K Poulose wrote: >> On 26/04/16 23:10, Mathieu Poirier wrote: >>> >>> This patch implement the AUX area interfaces required to >>> use the TMC (configured as an ETF) from the Perf sub-system. >>> >>> The heuristic is heavily borrowed from the ETB10 implementation. >>> >>> Signed-off-by: Mathieu Poirier >> >> >>> + >>> + /* >>> + * Make sure the new size is aligned in accordance with >>> the >>> + * requirement explained above. >>> + */ >>> + to_read = handle->size & mask; >>> + /* Move the RAM read pointer up */ >>> + read_ptr = (write_ptr + drvdata->size) - to_read; >>> + /* Make sure we are still within our limits */ >>> + read_ptr &= ~(drvdata->size - 1); >> >> >> Correct me if I am wrong, I think this will break for ETR configuration >> (used from the following >> patch 17/18). Since, for ETR, RRP/RWP will return the lower 32bit AXI >> address (not the queue offset). >> So the last step would really spoil the read_ptr. We might have to set the >> read_ptr by adding the >> appropriate offset from DBAL0. > > That's a very good catch. It also means we ETR support (17/18) has to > be dropped from this set. I will do a respin of this patch only. And you also need (a separate patch) to fix the etb10 driver where this bug originated. Suzuki From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752862AbcD0RZd (ORCPT ); Wed, 27 Apr 2016 13:25:33 -0400 Received: from foss.arm.com ([217.140.101.70]:37329 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752338AbcD0RZc (ORCPT ); Wed, 27 Apr 2016 13:25:32 -0400 Subject: Re: [PATCH V4 16/18] coresight: tmc: implementing TMC-ETF AUX space API To: Mathieu Poirier References: <1461708634-6327-1-git-send-email-mathieu.poirier@linaro.org> <1461708634-6327-17-git-send-email-mathieu.poirier@linaro.org> <5720A0AF.9090107@arm.com> Cc: "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" From: Suzuki K Poulose Message-ID: <5720F609.6030501@arm.com> Date: Wed, 27 Apr 2016 18:25:29 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.6.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 27/04/16 18:22, Mathieu Poirier wrote: > On 27 April 2016 at 05:21, Suzuki K Poulose wrote: >> On 26/04/16 23:10, Mathieu Poirier wrote: >>> >>> This patch implement the AUX area interfaces required to >>> use the TMC (configured as an ETF) from the Perf sub-system. >>> >>> The heuristic is heavily borrowed from the ETB10 implementation. >>> >>> Signed-off-by: Mathieu Poirier >> >> >>> + >>> + /* >>> + * Make sure the new size is aligned in accordance with >>> the >>> + * requirement explained above. >>> + */ >>> + to_read = handle->size & mask; >>> + /* Move the RAM read pointer up */ >>> + read_ptr = (write_ptr + drvdata->size) - to_read; >>> + /* Make sure we are still within our limits */ >>> + read_ptr &= ~(drvdata->size - 1); >> >> >> Correct me if I am wrong, I think this will break for ETR configuration >> (used from the following >> patch 17/18). Since, for ETR, RRP/RWP will return the lower 32bit AXI >> address (not the queue offset). >> So the last step would really spoil the read_ptr. We might have to set the >> read_ptr by adding the >> appropriate offset from DBAL0. > > That's a very good catch. It also means we ETR support (17/18) has to > be dropped from this set. I will do a respin of this patch only. And you also need (a separate patch) to fix the etb10 driver where this bug originated. Suzuki