From patchwork Wed Jun 1 12:23:45 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: 12866853 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 14199C433EF for ; Wed, 1 Jun 2022 12:24:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235345AbiFAMYk (ORCPT ); Wed, 1 Jun 2022 08:24:40 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53180 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237528AbiFAMYd (ORCPT ); Wed, 1 Jun 2022 08:24:33 -0400 Received: from alexa-out.qualcomm.com (alexa-out.qualcomm.com [129.46.98.28]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6AFF73E5F9; Wed, 1 Jun 2022 05:24:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=quicinc.com; i=@quicinc.com; q=dns/txt; s=qcdkim; t=1654086271; x=1685622271; h=from:to:cc:subject:date:message-id:in-reply-to: references; bh=Qs33nKS0x+bYUbXz3PUD+x5Womx8hyZMkTh7yVOAk44=; b=bHdvL7L8mmLpMYqBLnZLRQlXix/ZGHOWucHaQfAtV5UUq1t442lEjQaR vAWIH3CHu8BsIQ0oRjUYyaNKgk55ZY+67FuW8cZUwNnafzDdk97nAG4TM 8m1wK8Cu1edvBMiw4s4wycl4yw8OPT7EpkrpZTDYnweg6p2rDF+8cpIwM E=; Received: from ironmsg08-lv.qualcomm.com ([10.47.202.152]) by alexa-out.qualcomm.com with ESMTP; 01 Jun 2022 05:24:31 -0700 X-QCInternal: smtphost Received: from ironmsg02-blr.qualcomm.com ([10.86.208.131]) by ironmsg08-lv.qualcomm.com with ESMTP/TLS/AES256-SHA; 01 Jun 2022 05:24:29 -0700 X-QCInternal: smtphost Received: from hu-krichai-hyd.qualcomm.com (HELO hu-sgudaval-hyd.qualcomm.com) ([10.213.110.37]) by ironmsg02-blr.qualcomm.com with ESMTP; 01 Jun 2022 17:54:13 +0530 Received: by hu-sgudaval-hyd.qualcomm.com (Postfix, from userid 4058933) id 129AD4140; Wed, 1 Jun 2022 17:54:12 +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, quic_vbadigan@quicinc.com, quic_ramkri@quicinc.com, manivannan.sadhasivam@linaro.org, swboyd@chromium.org, Krishna chaitanya chundru , Bjorn Helgaas , "Saheed O. Bolarinwa" , =?utf-8?q?Krzysztof_Wilcz?= =?utf-8?q?y=C5=84ski?= , Rajat Jain Subject: [PATCH v3] PCI/ASPM: Update LTR threshold based upon reported max latencies Date: Wed, 1 Jun 2022 17:53:45 +0530 Message-Id: <1654086232-17055-1-git-send-email-quic_krichai@quicinc.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1646679549-12494-1-git-send-email-quic_pmaliset@quicinc.com> References: <1646679549-12494-1-git-send-email-quic_pmaliset@quicinc.com> Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org In ASPM driver, LTR threshold scale and value is updating based on tcommon_mode and t_poweron values. In kioxia NVMe L1.2 is failing due to LTR threshold scale and value is greater values than max snoop/non-snoop value. Based on PCIe r4.1, sec 5.5.1, L1.2 substate must be entered when reported snoop/no-snoop values is greather than or equal to LTR_L1.2_THRESHOLD value. Suggested-by: Prasad Malisetty Signed-off-by: Krishna chaitanya chundru --- I am takking this patch forward as prasad is no more working with our org. Changes since v2: - Replaced LTRME logic with max snoop/no-snoop latencies check. Changes since v1: - Added missing variable declaration in v1 patch --- drivers/pci/pcie/aspm.c | 22 +++++++++++++++++++++- 1 file changed, 21 insertions(+), 1 deletion(-) diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c index a96b742..4a15e50 100644 --- a/drivers/pci/pcie/aspm.c +++ b/drivers/pci/pcie/aspm.c @@ -465,10 +465,19 @@ static void aspm_calc_l1ss_info(struct pcie_link_state *link, u32 ctl1 = 0, ctl2 = 0; u32 pctl1, pctl2, cctl1, cctl2; u32 pl1_2_enables, cl1_2_enables; + int ltr; + u16 max_snoop_lat = 0, max_nosnoop_lat = 0; if (!(link->aspm_support & ASPM_STATE_L1_2_MASK)) return; + ltr = pci_find_ext_capability(child, PCI_EXT_CAP_ID_LTR); + if (!ltr) + return; + + pci_read_config_word(child, ltr + PCI_LTR_MAX_SNOOP_LAT, &max_snoop_lat); + pci_read_config_word(child, ltr + PCI_LTR_MAX_NOSNOOP_LAT, &max_nosnoop_lat); + /* Choose the greater of the two Port Common_Mode_Restore_Times */ val1 = (parent_l1ss_cap & PCI_L1SS_CAP_CM_RESTORE_TIME) >> 8; val2 = (child_l1ss_cap & PCI_L1SS_CAP_CM_RESTORE_TIME) >> 8; @@ -501,7 +510,18 @@ static void aspm_calc_l1ss_info(struct pcie_link_state *link, */ l1_2_threshold = 2 + 4 + t_common_mode + t_power_on; encode_l12_threshold(l1_2_threshold, &scale, &value); - ctl1 |= t_common_mode << 8 | scale << 29 | value << 16; + + /* + * If the max snoop and no snoop latencies are '0', then avoid updating scale + * and value. + * + * Based on PCIe r4.1, sec 5.5.1, L1.2 substate must be entered when reported + * snoop/no-snoop values is greather than or equal to LTR_L1.2_THRESHOLD value. + */ + if ((max_snoop_lat == 0) && (max_nosnoop_lat == 0)) + ctl1 |= t_common_mode << 8; + else + ctl1 |= t_common_mode << 8 | scale << 29 | value << 16; /* Some broken devices only support dword access to L1 SS */ pci_read_config_dword(parent, parent->l1ss + PCI_L1SS_CTL1, &pctl1);