From patchwork Thu May 16 05:52:45 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Manikanta Maddireddy X-Patchwork-Id: 10945651 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 7F280924 for ; Thu, 16 May 2019 05:53:39 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 6ED9C28AAF for ; Thu, 16 May 2019 05:53:39 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 6333B28AB1; Thu, 16 May 2019 05:53:39 +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 ECA2528AAF for ; Thu, 16 May 2019 05:53:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726547AbfEPFxi (ORCPT ); Thu, 16 May 2019 01:53:38 -0400 Received: from hqemgate14.nvidia.com ([216.228.121.143]:8915 "EHLO hqemgate14.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726277AbfEPFxi (ORCPT ); Thu, 16 May 2019 01:53:38 -0400 Received: from hqpgpgate101.nvidia.com (Not Verified[216.228.121.13]) by hqemgate14.nvidia.com (using TLS: TLSv1.2, DES-CBC3-SHA) id ; Wed, 15 May 2019 22:53:42 -0700 Received: from hqmail.nvidia.com ([172.20.161.6]) by hqpgpgate101.nvidia.com (PGP Universal service); Wed, 15 May 2019 22:53:35 -0700 X-PGP-Universal: processed; by hqpgpgate101.nvidia.com on Wed, 15 May 2019 22:53:35 -0700 Received: from HQMAIL101.nvidia.com (172.20.187.10) by HQMAIL106.nvidia.com (172.18.146.12) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Thu, 16 May 2019 05:53:35 +0000 Received: from manikanta-bm2.nvidia.com (10.124.1.5) by HQMAIL101.nvidia.com (172.20.187.10) with Microsoft SMTP Server id 15.0.1473.3 via Frontend Transport; Thu, 16 May 2019 05:53:32 +0000 From: Manikanta Maddireddy To: , , , , , , CC: , , , Manikanta Maddireddy Subject: [PATCH V4 06/28] PCI: tegra: Add PCIe Gen2 link speed support Date: Thu, 16 May 2019 11:22:45 +0530 Message-ID: <20190516055307.25737-7-mmaddireddy@nvidia.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190516055307.25737-1-mmaddireddy@nvidia.com> References: <20190516055307.25737-1-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=1557986022; bh=/0i47jZIURS0+sx1zJ0Nhi9/E+jRmSm86XvBHfmIg38=; h=X-PGP-Universal:From:To:CC:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:X-NVConfidentiality:MIME-Version: Content-Type; b=OlhKAfcBf48oXB7oWW5o8pngkIG18av2/FtLV16YMK/y+WUZwA2pGPHen3+IxpAvl EIOhZA+GDSGhGU6hWr5lgZlagp9MjdkHhA8vGOC9k2HRrnjsMpMGpTnbGshjwW1xrP yR0EDW8eRpU4uOR9QZSLqvO+2YvMb1fDTTFFkezqI/tiP1OoayhmEi4+1Yx1hjL1D3 UvuVciTFoBgXakeLRL6jxo7gkQLFjJWfp68xh8LqfyxdkGLl0sKaTZiwS+CCGgo7s5 lVKitrrMb7yxbUk3HWdqefjf3p7YAec0ARUZdHVRdKriPwFFxmidDB/INIEOq0ePMS 5bYZSeaFNia8g== 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 --- V4: No change 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)