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=-6.5 required=3.0 tests=FREEMAIL_FORGED_FROMDOMAIN, FREEMAIL_FROM,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,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 37C3CC31E45 for ; Thu, 13 Jun 2019 15:52:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1755320851 for ; Thu, 13 Jun 2019 15:52:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731879AbfFMPwV (ORCPT ); Thu, 13 Jun 2019 11:52:21 -0400 Received: from ns.iliad.fr ([212.27.33.1]:58270 "EHLO ns.iliad.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731649AbfFMJKm (ORCPT ); Thu, 13 Jun 2019 05:10:42 -0400 Received: from ns.iliad.fr (localhost [127.0.0.1]) by ns.iliad.fr (Postfix) with ESMTP id 84C7C20AC3; Thu, 13 Jun 2019 11:10:39 +0200 (CEST) Received: from [192.168.108.49] (freebox.vlq16.iliad.fr [213.36.7.13]) by ns.iliad.fr (Postfix) with ESMTP id 6B7F0207ED; Thu, 13 Jun 2019 11:10:39 +0200 (CEST) Subject: Re: [PATCH] phy: qcom-qmp: Correct READY_STATUS poll break condition To: Bjorn Andersson , Kishon Vijay Abraham I Cc: MSM , LKML , Evan Green , Vivek Gautam , Niklas Cassel , Stanimir Varbanov References: <20190604232443.3417-1-bjorn.andersson@linaro.org> <619d2559-6d88-e795-76e0-3078236933ef@free.fr> <20190612172501.GY4814@minitux> From: Marc Gonzalez Message-ID: <3570d880-2b76-88ae-8721-e75cf5acec4c@free.fr> Date: Thu, 13 Jun 2019 11:10:39 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: <20190612172501.GY4814@minitux> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Virus-Scanned: ClamAV using ClamSMTP ; ns.iliad.fr ; Thu Jun 13 11:10:39 2019 +0200 (CEST) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/06/2019 19:25, Bjorn Andersson wrote: > On Wed 12 Jun 09:24 PDT 2019, Marc Gonzalez wrote: > >> On 05/06/2019 01:24, Bjorn Andersson wrote: >> >>> After issuing a PHY_START request to the QMP, the hardware documentation >>> states that the software should wait for the PCS_READY_STATUS to become 1. >>> >>> With the introduction of c9b589791fc1 ("phy: qcom: Utilize UFS reset >>> controller") an additional 1ms delay was introduced between the start >>> request and the check of the status bit. This greatly increases the >>> chances for the hardware to actually becoming ready before the status >>> bit is read. >>> >>> The result can be seen in that UFS PHY enabling is now reported as a >>> failure in 10% of the boots on SDM845, which is a clear regression from >>> the previous rare/occasional failure. >>> >>> This patch fixes the "break condition" of the poll to check for the >>> correct state of the status bit. >>> >>> Unfortunately PCIe on 8996 and 8998 does not specify the mask_pcs_ready >>> register, which means that the code checks a bit that's always 0. So the >>> patch also fixes these, in order to not regress these targets. >>> >>> Cc: stable@vger.kernel.org >>> Cc: Evan Green >>> Cc: Marc Gonzalez >>> Cc: Vivek Gautam >>> Fixes: 73d7ec899bd8 ("phy: qcom-qmp: Add msm8998 PCIe QMP PHY support") >>> Fixes: e78f3d15e115 ("phy: qcom-qmp: new qmp phy driver for qcom-chipsets") >>> Signed-off-by: Bjorn Andersson >>> --- >>> >>> @Kishon, this is a regression spotted in v5.2-rc1, so please consider applying >>> this towards v5.2. >>> >>> drivers/phy/qualcomm/phy-qcom-qmp.c | 4 +++- >>> 1 file changed, 3 insertions(+), 1 deletion(-) >>> >>> diff --git a/drivers/phy/qualcomm/phy-qcom-qmp.c b/drivers/phy/qualcomm/phy-qcom-qmp.c >>> index cd91b4179b10..43abdfd0deed 100644 >>> --- a/drivers/phy/qualcomm/phy-qcom-qmp.c >>> +++ b/drivers/phy/qualcomm/phy-qcom-qmp.c >>> @@ -1074,6 +1074,7 @@ static const struct qmp_phy_cfg msm8996_pciephy_cfg = { >>> >>> .start_ctrl = PCS_START | PLL_READY_GATE_EN, >>> .pwrdn_ctrl = SW_PWRDN | REFCLK_DRV_DSBL, >>> + .mask_pcs_ready = PHYSTATUS, >>> .mask_com_pcs_ready = PCS_READY, >>> >>> .has_phy_com_ctrl = true, >>> @@ -1253,6 +1254,7 @@ static const struct qmp_phy_cfg msm8998_pciephy_cfg = { >>> >>> .start_ctrl = SERDES_START | PCS_START, >>> .pwrdn_ctrl = SW_PWRDN | REFCLK_DRV_DSBL, >>> + .mask_pcs_ready = PHYSTATUS, >>> .mask_com_pcs_ready = PCS_READY, >>> }; >>> >>> @@ -1547,7 +1549,7 @@ static int qcom_qmp_phy_enable(struct phy *phy) >>> status = pcs + cfg->regs[QPHY_PCS_READY_STATUS]; >>> mask = cfg->mask_pcs_ready; >>> >>> - ret = readl_poll_timeout(status, val, !(val & mask), 1, >>> + ret = readl_poll_timeout(status, val, val & mask, 1, >>> PHY_INIT_COMPLETE_TIMEOUT); >>> if (ret) { >>> dev_err(qmp->dev, "phy initialization timed-out\n"); >> >> Your patch made me realize that: >> msm8998_pciephy_cfg.has_phy_com_ctrl = false >> thus >> msm8998_pciephy_cfg.mask_com_pcs_ready is useless, AFAICT. > > While 8998 has a COM block, it does (among other things) not have a > ready bit. So afaict has_phy_com_ctrl = false is correct. Pfff... Working blind without the HPG sucks... > The addition of mask_pcs_ready is part of resolving the regression in > 5.2, so I suggest that we remove mask_com_pcs_ready separately. I agree that it should be done separately. I'll send a patch on top of yours. >> (I copied msm8996_pciephy_cfg for msm8998_pciephy_cfg) >> >> Does msm8996_pciephy_cfg really need both mask_pcs_ready AND >> mask_com_pcs_ready? > > 8996 has a COM block and it contains both the control bits and the > status bits, so that looks correct. Thanks for checking. >> I'll test your patch tomorrow. > > I appreciate that. Here are my observations for a 8998 board: 1) If I apply only the readl_poll_timeout() fix (not the mask_pcs_ready fixup) qcom_pcie_probe() fails with a timeout in phy_init. => this is in line with your regression analysis. 2) Your patch also fixes a long-standing bug in UFS init whereby sending lots of information to the console during phy init would lead to an incorrectly diagnosed time-out. Good stuff! Reviewed-by: Marc Gonzalez Tested-by: Marc Gonzalez Regards.