From patchwork Mon May 13 18:07:21 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Manikanta Maddireddy X-Patchwork-Id: 10941471 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id BB6F4933 for ; Mon, 13 May 2019 18:08:30 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id AAAE8283A8 for ; Mon, 13 May 2019 18:08:30 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 9EB97283C9; Mon, 13 May 2019 18:08:30 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.0 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 34754283A8 for ; Mon, 13 May 2019 18:08:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732285AbfEMSI3 (ORCPT ); Mon, 13 May 2019 14:08:29 -0400 Received: from hqemgate14.nvidia.com ([216.228.121.143]:18050 "EHLO hqemgate14.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732266AbfEMSI3 (ORCPT ); Mon, 13 May 2019 14:08:29 -0400 Received: from hqpgpgate101.nvidia.com (Not Verified[216.228.121.13]) by hqemgate14.nvidia.com (using TLS: TLSv1.2, DES-CBC3-SHA) id ; Mon, 13 May 2019 11:08:34 -0700 Received: from hqmail.nvidia.com ([172.20.161.6]) by hqpgpgate101.nvidia.com (PGP Universal service); Mon, 13 May 2019 11:08:28 -0700 X-PGP-Universal: processed; by hqpgpgate101.nvidia.com on Mon, 13 May 2019 11:08:28 -0700 Received: from HQMAIL102.nvidia.com (172.18.146.10) by HQMAIL104.nvidia.com (172.18.146.11) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Mon, 13 May 2019 18:08:27 +0000 Received: from HQMAIL107.nvidia.com (172.20.187.13) by HQMAIL102.nvidia.com (172.18.146.10) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Mon, 13 May 2019 18:08:27 +0000 Received: from manikanta-bm2.nvidia.com (172.20.13.39) by HQMAIL.nvidia.com (172.20.187.13) with Microsoft SMTP Server id 15.0.1473.3 via Frontend Transport; Mon, 13 May 2019 18:08:23 +0000 From: Manikanta Maddireddy To: , , , , , , CC: , , , Manikanta Maddireddy Subject: [PATCH V3 06/29] PCI: tegra: Add PCIe Gen2 link speed support Date: Mon, 13 May 2019 23:37:21 +0530 Message-ID: <20190513180744.16493-7-mmaddireddy@nvidia.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190513180744.16493-1-mmaddireddy@nvidia.com> References: <20190513180744.16493-1-mmaddireddy@nvidia.com> X-NVConfidentiality: public MIME-Version: 1.0 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1; t=1557770915; bh=hUYNK4rcFKkQ03tktRZwwKKfgc9qaMrEWbWjm38Rtm8=; h=X-PGP-Universal:From:To:CC:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:X-NVConfidentiality:MIME-Version: Content-Type; b=F1iJ30f6h1igG18Mdi6M4F5xWYeTbIxSJMnYRRv/2maVzLTUHBnGHI7Kpf6ZV19a8 djSX2Blv+bEvhSpuIotCSg2c1knXdfsUPFCqQIU4DIucfdILpyiJXo396ZiPt6IjQY Al4SSgNNmW//KdHC2Tu+5LRDMxhhih8VpepJw4Kql5UXPgopNloTQT+KfQH3LiGQ4K 0sfXk9xoeSX8vJfI5dT1krk9xm43CU7iandM/sjre4+u+/BLZm6XqCOKSl9/CubMpE IsR746BnuWF0dCqGhxSKec057S97Klt89UNbdIIMEL6+t4C50n604lJe5W10LkWd12 4ejYz/Nc9L9Ng== Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Tegra124, Tegra132, Tegra210 and Tegra186 support Gen2 link speed. After PCIe link is up in Gen1, set target link speed as Gen2 and retrain link. Link switches to Gen2 speed if Gen2 capable end point is connected, else link stays in Gen1. Per PCIe 4.0r0.9 sec 7.6.3.7 implementation note, driver need to wait for PCIe LTSSM to come back from recovery before retraining the link. Signed-off-by: Manikanta Maddireddy Acked-by: Thierry Reding --- V3: Added blank line after each while loop. V2: Changed "for loop" to "while", to make it compact and handled coding style comments. drivers/pci/controller/pci-tegra.c | 64 ++++++++++++++++++++++++++++++ 1 file changed, 64 insertions(+) diff --git a/drivers/pci/controller/pci-tegra.c b/drivers/pci/controller/pci-tegra.c index 015add4e345b..cd542a8af618 100644 --- a/drivers/pci/controller/pci-tegra.c +++ b/drivers/pci/controller/pci-tegra.c @@ -191,6 +191,8 @@ #define RP_LINK_CONTROL_STATUS_DL_LINK_ACTIVE 0x20000000 #define RP_LINK_CONTROL_STATUS_LINKSTAT_MASK 0x3fff0000 +#define RP_LINK_CONTROL_STATUS_2 0x000000b0 + #define PADS_CTL_SEL 0x0000009c #define PADS_CTL 0x000000a0 @@ -226,6 +228,7 @@ #define PADS_REFCLK_CFG_DRVI_SHIFT 12 /* 15:12 */ #define PME_ACK_TIMEOUT 10000 +#define LINK_RETRAIN_TIMEOUT 100000 /* in usec */ struct tegra_msi { struct msi_controller chip; @@ -2089,6 +2092,64 @@ static bool tegra_pcie_port_check_link(struct tegra_pcie_port *port) return false; } +static void tegra_pcie_change_link_speed(struct tegra_pcie *pcie) +{ + struct device *dev = pcie->dev; + struct tegra_pcie_port *port, *tmp; + ktime_t deadline; + u32 value; + + list_for_each_entry_safe(port, tmp, &pcie->ports, list) { + /* + * "Supported Link Speeds Vector" in "Link Capabilities 2" + * is not supported by Tegra. tegra_pcie_change_link_speed() + * is called only for Tegra chips which support Gen2. + * So there no harm if supported link speed is not verified. + */ + value = readl(port->base + RP_LINK_CONTROL_STATUS_2); + value &= ~PCI_EXP_LNKSTA_CLS; + value |= PCI_EXP_LNKSTA_CLS_5_0GB; + writel(value, port->base + RP_LINK_CONTROL_STATUS_2); + + /* + * Poll until link comes back from recovery to avoid race + * condition. + */ + deadline = ktime_add_us(ktime_get(), LINK_RETRAIN_TIMEOUT); + + while (ktime_before(ktime_get(), deadline)) { + value = readl(port->base + RP_LINK_CONTROL_STATUS); + if ((value & PCI_EXP_LNKSTA_LT) == 0) + break; + + usleep_range(2000, 3000); + } + + if (value & PCI_EXP_LNKSTA_LT) + dev_warn(dev, "PCIe port %u link is in recovery\n", + port->index); + + /* Retrain the link */ + value = readl(port->base + RP_LINK_CONTROL_STATUS); + value |= PCI_EXP_LNKCTL_RL; + writel(value, port->base + RP_LINK_CONTROL_STATUS); + + deadline = ktime_add_us(ktime_get(), LINK_RETRAIN_TIMEOUT); + + while (ktime_before(ktime_get(), deadline)) { + value = readl(port->base + RP_LINK_CONTROL_STATUS); + if ((value & PCI_EXP_LNKSTA_LT) == 0) + break; + + usleep_range(2000, 3000); + } + + if (value & PCI_EXP_LNKSTA_LT) + dev_err(dev, "failed to retrain link of port %u\n", + port->index); + } +} + static void tegra_pcie_enable_ports(struct tegra_pcie *pcie) { struct device *dev = pcie->dev; @@ -2113,6 +2174,9 @@ static void tegra_pcie_enable_ports(struct tegra_pcie *pcie) tegra_pcie_port_disable(port); tegra_pcie_port_free(port); } + + if (pcie->soc->has_gen2) + tegra_pcie_change_link_speed(pcie); } static void tegra_pcie_disable_ports(struct tegra_pcie *pcie)