From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751937AbdFOKNT (ORCPT ); Thu, 15 Jun 2017 06:13:19 -0400 Received: from foss.arm.com ([217.140.101.70]:43622 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750777AbdFOKNS (ORCPT ); Thu, 15 Jun 2017 06:13:18 -0400 Subject: Re: [PATCH 05/12] coresight tmc: Add helpers for accessing 64bit registers To: Mathieu Poirier References: <1497278211-5001-1-git-send-email-suzuki.poulose@arm.com> <1497278211-5001-6-git-send-email-suzuki.poulose@arm.com> <20170614174904.GA22030@xps15> Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org From: Suzuki K Poulose Message-ID: Date: Thu, 15 Jun 2017 11:13:15 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.8.0 MIME-Version: 1.0 In-Reply-To: <20170614174904.GA22030@xps15> 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 14/06/17 18:49, Mathieu Poirier wrote: > On Mon, Jun 12, 2017 at 03:36:44PM +0100, Suzuki K Poulose wrote: >> Coresight TMC splits 64bit registers into a pair of 32bit registers >> (e.g DBA, RRP, RWP). Provide helpers to read/write to these registers. > > I'm good with this patch but please specify these changes are to support the > SoC-600 suite. That way when we look back at this set in a couple of years we > don't loose hair thinking we've been carrying bugs all this time. To be honest, these are not necessarily just for the support of SoC-600. It is applies to the current driver with SoC-400, as you could see below, where we have always assumed that the RRP/RWP/DBA HI bits are always 0. Technically, the TMC supports upto 40bits and hence we have been doing it wrong. >> - read_ptr = readl_relaxed(drvdata->base + TMC_RRP); >> - write_ptr = readl_relaxed(drvdata->base + TMC_RWP); >> + read_ptr = tmc_read_rrp(drvdata); >> + write_ptr = tmc_read_rwp(drvdata); >> - writel_relaxed(read_ptr, drvdata->base + TMC_RRP); >> + tmc_write_rrp(drvdata, read_ptr); >> perf_aux_output_flag(handle, PERF_AUX_FLAG_TRUNCATED); >> writel_relaxed(axictl, drvdata->base + TMC_AXICTL); >> + tmc_write_dba(drvdata, drvdata->paddr); >> >> - writel_relaxed(drvdata->paddr, drvdata->base + TMC_DBALO); >> - writel_relaxed(0x0, drvdata->base + TMC_DBAHI); >> >> - rwp = readl_relaxed(drvdata->base + TMC_RWP); >> + rwp = tmc_read_rwp(drvdata); >> val = readl_relaxed(drvdata->base + TMC_STS); >> Suzuki