From patchwork Fri Jun 3 07:54:19 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: 579031 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 04FBBC433EF for ; Fri, 3 Jun 2022 07:55:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242395AbiFCHzX (ORCPT ); Fri, 3 Jun 2022 03:55:23 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49432 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237453AbiFCHzX (ORCPT ); Fri, 3 Jun 2022 03:55:23 -0400 Received: from alexa-out.qualcomm.com (alexa-out.qualcomm.com [129.46.98.28]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D156135DC1; Fri, 3 Jun 2022 00:55:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=quicinc.com; i=@quicinc.com; q=dns/txt; s=qcdkim; t=1654242922; x=1685778922; h=from:to:cc:subject:date:message-id:in-reply-to: references; bh=idd1rNj/CX3H0NOTNJzw+JpUrFbH6zOoQ/T+QLi/PZg=; b=dgSCgdHIlLH9b/SEqOSnzVr1lxcd1X96WmuBSZm/LUihPNqaavs/eR/Q Z0Qw6SOkx7ZCimzp9h+8p4AVwqC2vQ3hk/7Zq55BoDDBS5GX055g/BvdG nilYvHuvkABIN9TvkxT52umfsvcW1Qk2CCHsFptfFsgCPRYOUJm1jsXg6 s=; Received: from ironmsg08-lv.qualcomm.com ([10.47.202.152]) by alexa-out.qualcomm.com with ESMTP; 03 Jun 2022 00:55:22 -0700 X-QCInternal: smtphost Received: from ironmsg01-blr.qualcomm.com ([10.86.208.130]) by ironmsg08-lv.qualcomm.com with ESMTP/TLS/AES256-SHA; 03 Jun 2022 00:55:04 -0700 X-QCInternal: smtphost Received: from hu-krichai-hyd.qualcomm.com (HELO hu-sgudaval-hyd.qualcomm.com) ([10.213.110.37]) by ironmsg01-blr.qualcomm.com with ESMTP; 03 Jun 2022 13:24:44 +0530 Received: by hu-sgudaval-hyd.qualcomm.com (Postfix, from userid 4058933) id 33E644151; Fri, 3 Jun 2022 13:24:43 +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_hemantk@quicinc.com, quic_nitegupt@quicinc.com, quic_skananth@quicinc.com, quic_ramkri@quicinc.com, manivannan.sadhasivam@linaro.org, swboyd@chromium.org, Prasad Malisetty , Krishna chaitanya chundru , Bjorn Helgaas , "Saheed O. Bolarinwa" , =?utf-8?q?Krzysztof_Wilcz?= =?utf-8?q?y=C5=84ski?= , Rajat Jain Subject: [PATCH v4] PCI/ASPM: Update LTR threshold based upon reported max latencies Date: Fri, 3 Jun 2022 13:24:19 +0530 Message-Id: <1654242861-15695-1-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-arm-msm@vger.kernel.org From: Prasad Malisetty In ASPM driver, LTR threshold scale and value are updated based on tcommon_mode and t_poweron values. In kioxia NVMe L1.2 is failing due to LTR threshold scale and value are 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. Signed-off-by: Prasad Malisetty Signed-off-by: Krishna chaitanya chundru --- I am taking this patch forward as prasad is no more working with our org. changes since v3: - Changed the logic to include this condition "snoop/nosnoop latencies are not equal to zero and lower than LTR_L1.2_THRESHOLD" 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 | 32 ++++++++++++++++++++++++++++++++ 1 file changed, 32 insertions(+) diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c index a96b742..c8f6253 100644 --- a/drivers/pci/pcie/aspm.c +++ b/drivers/pci/pcie/aspm.c @@ -461,14 +461,36 @@ static void aspm_calc_l1ss_info(struct pcie_link_state *link, { struct pci_dev *child = link->downstream, *parent = link->pdev; u32 val1, val2, scale1, scale2; + u32 max_val, max_scale, max_snp_scale, max_snp_val, max_nsnp_scale, max_nsnp_val; u32 t_common_mode, t_power_on, l1_2_threshold, scale, value; u32 ctl1 = 0, ctl2 = 0; u32 pctl1, pctl2, cctl1, cctl2; u32 pl1_2_enables, cl1_2_enables; + u16 ltr; + u16 max_snoop_lat, max_nosnoop_lat; 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); + + max_snp_scale = (max_snoop_lat & PCI_LTR_SCALE_MASK) >> PCI_LTR_SCALE_SHIFT; + max_snp_val = (max_snoop_lat & PCI_LTR_VALUE_MASK); + + max_nsnp_scale = (max_nosnoop_lat & PCI_LTR_SCALE_MASK) >> PCI_LTR_SCALE_SHIFT; + max_nsnp_val = (max_nosnoop_lat & PCI_LTR_VALUE_MASK); + + /* choose the greater max scale value between snoop and no snoop value*/ + max_scale = (max_snp_scale > max_nsnp_scale) ? max_snp_scale: max_nsnp_scale; + + /* choose the greater max value between snoop and no snoop scales */ + max_val = (max_snp_val > max_nsnp_val) ? max_snp_val: max_nsnp_val; + /* 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; @@ -501,6 +523,16 @@ 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); + + /* + * Based on PCIe r4.1, sec 5.5.1, L1.2 substate must be entered when reported + * snoop/no-snoop values are greather than or equal to LTR_L1.2_THRESHOLD value. + */ + if (scale > max_scale) + scale = max_scale; + if (value > max_val) + value = max_val; + ctl1 |= t_common_mode << 8 | scale << 29 | value << 16; /* Some broken devices only support dword access to L1 SS */