From patchwork Tue Sep 20 10:22:24 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Krishna chaitanya chundru X-Patchwork-Id: 12981856 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 78A4BC6FA96 for ; Tue, 20 Sep 2022 10:23:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230038AbiITKW7 (ORCPT ); Tue, 20 Sep 2022 06:22:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58300 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229928AbiITKW4 (ORCPT ); Tue, 20 Sep 2022 06:22:56 -0400 Received: from mx0b-0031df01.pphosted.com (mx0b-0031df01.pphosted.com [205.220.180.131]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C21B850194; Tue, 20 Sep 2022 03:22:54 -0700 (PDT) Received: from pps.filterd (m0279868.ppops.net [127.0.0.1]) by mx0a-0031df01.pphosted.com (8.17.1.5/8.17.1.5) with ESMTP id 28KAMYCJ030209; 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Tue, 20 Sep 2022 10:22:30 GMT Received: from pps.reinject (localhost [127.0.0.1]) by APBLRPPMTA01.qualcomm.com (PPS) with ESMTPS id 3jnqrbnbqq-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Tue, 20 Sep 2022 10:22:30 +0000 Received: from APBLRPPMTA01.qualcomm.com (APBLRPPMTA01.qualcomm.com [127.0.0.1]) by pps.reinject (8.17.1.5/8.17.1.5) with ESMTP id 28KAMUG8016159; Tue, 20 Sep 2022 10:22:30 GMT Received: from hu-sgudaval-hyd.qualcomm.com (hu-krichai-hyd.qualcomm.com [10.213.110.37]) by APBLRPPMTA01.qualcomm.com (PPS) with ESMTP id 28KAMTb4016149; Tue, 20 Sep 2022 10:22:30 +0000 Received: by hu-sgudaval-hyd.qualcomm.com (Postfix, from userid 4058933) id 5E18D19F9; Tue, 20 Sep 2022 15:52:29 +0530 (+0530) From: Krishna chaitanya chundru To: helgaas@kernel.org Cc: linux-pci@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, mka@chromium.org, quic_vbadigan@quicinc.com, quic_hemantk@quicinc.com, quic_nitegupt@quicinc.com, quic_skananth@quicinc.com, quic_ramkri@quicinc.com, manivannan.sadhasivam@linaro.org, swboyd@chromium.org, dmitry.baryshkov@linaro.org, svarbanov@mm-sol.com, agross@kernel.org, andersson@kernel.org, konrad.dybcio@somainline.org, lpieralisi@kernel.org, robh@kernel.org, kw@linux.com, bhelgaas@google.com, linux-phy@lists.infradead.org, vkoul@kernel.org, kishon@ti.com, mturquette@baylibre.com, linux-clk@vger.kernel.org, Krishna chaitanya chundru , Bjorn Andersson Subject: [PATCH v7 2/5] PCI: qcom: Add retry logic for link to be stable in either L1.1 or L1.2 Date: Tue, 20 Sep 2022 15:52:24 +0530 Message-Id: <1663669347-29308-3-git-send-email-quic_krichai@quicinc.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1663669347-29308-1-git-send-email-quic_krichai@quicinc.com> References: <1663669347-29308-1-git-send-email-quic_krichai@quicinc.com> X-QCInternal: smtphost X-QCInternal: smtphost X-Proofpoint-Virus-Version: vendor=nai engine=6200 definitions=5800 signatures=585085 X-Proofpoint-Virus-Version: vendor=nai engine=6200 definitions=5800 signatures=585085 X-Proofpoint-GUID: MVX-zVMiMf09preCe-06zwyqS_L4eeRU X-Proofpoint-ORIG-GUID: MVX-zVMiMf09preCe-06zwyqS_L4eeRU X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.895,Hydra:6.0.528,FMLib:17.11.122.1 definitions=2022-09-20_02,2022-09-16_01,2022-06-22_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 malwarescore=0 adultscore=0 priorityscore=1501 suspectscore=0 bulkscore=0 phishscore=0 mlxscore=0 impostorscore=0 clxscore=1015 mlxlogscore=951 lowpriorityscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2209130000 definitions=main-2209200062 Precedence: bulk List-ID: X-Mailing-List: linux-clk@vger.kernel.org When link is in L1ss(L1.1 or L1.2), all the clocks will gate off and there will be no activity on the link. At that point clocks and phy can be turned off. If clocks got disabled before link enters L1ss the PCIe link goes down. Few endpoints are taking time more time to settle the link in L1 substates. When we check the traffic in protocol analyzer, we see some DLLP packets going on still. So Wait for max time of 200ms for the link to be stable in L1 substates. Signed-off-by: Krishna chaitanya chundru --- changes since v6: - updated comments. --- drivers/pci/controller/dwc/pcie-qcom.c | 46 ++++++++++++++++++++++++++-------- 1 file changed, 35 insertions(+), 11 deletions(-) diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c index 3f5424a..7a6f69e 100644 --- a/drivers/pci/controller/dwc/pcie-qcom.c +++ b/drivers/pci/controller/dwc/pcie-qcom.c @@ -1809,23 +1809,47 @@ static int qcom_pcie_probe(struct platform_device *pdev) static int __maybe_unused qcom_pcie_pm_suspend(struct qcom_pcie *pcie) { u32 val; + ktime_t timeout, start; struct dw_pcie *pci = pcie->pci; struct device *dev = pci->dev; - /* if the link is not active turn off clocks */ - if (!dw_pcie_link_up(pci)) { - dev_dbg(dev, "Link is not active\n"); - goto suspend; - } + /* + * When link is in L1ss, all the clocks will gate off and + * there will be no activity on the link. At that point clocks + * and phy can be turned off. If clocks got disabled before + * link enters L1ss the PCIe link goes down. + * + * Few endpoints are taking time more time to settle the link + * in L1ss. Wait for max of 200ms for the link to be stable in + * L1ss. + */ + start = ktime_get(); + /* Wait max 200 ms */ + timeout = ktime_add_ms(start, 200); + + while (1) { + /* if the liink is not active turn off clocks */ + if (!dw_pcie_link_up(pci)) { + dev_dbg(dev, "Link is not active\n"); + break; + } - /* if the link is not in l1ss don't turn off clocks */ - val = readl(pcie->parf + PCIE20_PARF_PM_STTS); - if (!(val & PCIE20_PARF_PM_STTS_LINKST_IN_L1SUB)) { - dev_warn(dev, "Link is not in L1ss\n"); - return 0; + /* if the link is not in l1ss don't turn off clocks */ + val = readl(pcie->parf + PCIE20_PARF_PM_STTS); + if ((val & PCIE20_PARF_PM_STTS_LINKST_IN_L1SUB)) { + dev_dbg(dev, "Link enters L1ss after %lld ms\n", + ktime_to_ms(ktime_get() - start)); + break; + } + + if (ktime_after(ktime_get(), timeout)) { + dev_warn(dev, "Link is not in L1ss\n"); + return 0; + } + + udelay(1000); } -suspend: if (pcie->cfg->ops->suspend) pcie->cfg->ops->suspend(pcie);