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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 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 B0D4EC38A2A for ; Thu, 7 May 2020 15:42:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 92F462083B for ; Thu, 7 May 2020 15:42:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726029AbgEGPmw (ORCPT ); Thu, 7 May 2020 11:42:52 -0400 Received: from foss.arm.com ([217.140.110.172]:34304 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725914AbgEGPmv (ORCPT ); Thu, 7 May 2020 11:42:51 -0400 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 08C801FB; Thu, 7 May 2020 08:42:51 -0700 (PDT) Received: from [10.37.12.53] (unknown [10.37.12.53]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 292293F68F; Thu, 7 May 2020 08:42:48 -0700 (PDT) Subject: Re: [PATCH] memory/samsung: Maybe wrong triming parameter To: Bernard Zhao , Kukjin Kim , Krzysztof Kozlowski , linux-pm@vger.kernel.org, linux-samsung-soc@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Cc: opensource.kernel@vivo.com References: <20200507114514.11589-1-bernard@vivo.com> From: Lukasz Luba Message-ID: <2eeb33f7-1acc-66bb-704a-b724fa0be0a8@arm.com> Date: Thu, 7 May 2020 16:42:46 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 MIME-Version: 1.0 In-Reply-To: <20200507114514.11589-1-bernard@vivo.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org Hi Bernard, On 5/7/20 12:45 PM, Bernard Zhao wrote: > In function create_timings_aligned, all the max is to use > dmc->min_tck->xxx, aligned with val dmc->timings->xxx. > But the dmc->timings->tFAW use dmc->min_tck->tXP? > Maybe this point is wrong parameter useing. > > Signed-off-by: Bernard Zhao > --- > drivers/memory/samsung/exynos5422-dmc.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/memory/samsung/exynos5422-dmc.c b/drivers/memory/samsung/exynos5422-dmc.c > index 81a1b1d01683..22a43d662833 100644 > --- a/drivers/memory/samsung/exynos5422-dmc.c > +++ b/drivers/memory/samsung/exynos5422-dmc.c > @@ -1091,7 +1091,7 @@ static int create_timings_aligned(struct exynos5_dmc *dmc, u32 *reg_timing_row, > /* power related timings */ > val = dmc->timings->tFAW / clk_period_ps; > val += dmc->timings->tFAW % clk_period_ps ? 1 : 0; > - val = max(val, dmc->min_tck->tXP); > + val = max(val, dmc->min_tck->tFAW); > reg = &timing_power[0]; > *reg_timing_power |= TIMING_VAL2REG(reg, val); > > Good catch! Indeed this should be a dmc->min_tck->tFAW used for clamping. It didn't show up in testing because the frequency values based on which the 'clk_period_ps' are calculated are sane. Check the dump below: [ 5.458227] DMC: mem tFAW=25000, clk_period_ps=6060 [ 5.461743] DMC: tFAW=5, tXP=2 val=5 [ 5.465273] DMC: mem tFAW=25000, clk_period_ps=4854 [ 5.470101] DMC: tFAW=5, tXP=2 val=6 [ 5.473668] DMC: mem tFAW=25000, clk_period_ps=3636 [ 5.478507] DMC: tFAW=5, tXP=2 val=7 [ 5.482072] DMC: mem tFAW=25000, clk_period_ps=2421 [ 5.486951] DMC: tFAW=5, tXP=2 val=11 [ 5.490531] DMC: mem tFAW=25000, clk_period_ps=1841 [ 5.495439] DMC: tFAW=5, tXP=2 val=14 [ 5.499113] DMC: mem tFAW=25000, clk_period_ps=1579 [ 5.503877] DMC: tFAW=5, tXP=2 val=16 [ 5.507476] DMC: mem tFAW=25000, clk_period_ps=1373 [ 5.512368] DMC: tFAW=5, tXP=2 val=19 [ 5.515968] DMC: mem tFAW=25000, clk_period_ps=1212 [ 5.520826] DMC: tFAW=5, tXP=2 val=21 That's why in the existing configuration it does not harm (the calculated 'val' is always >= 5) the board. But I think this patch should be applied (after small changes in the commit message). @Krzysztof could you have a look on the commit message or take the patch with small adjustment in the description, please? I conditionally give (because of this description): Reviewed-by: Lukasz Luba Thank you Bernard for reporting and fixing this. Regards, Lukasz