From patchwork Mon Jun 17 17:39:31 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Manikanta Maddireddy X-Patchwork-Id: 10999807 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 3CE30112C for ; Mon, 17 Jun 2019 17:40:23 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 2D6AB26E73 for ; Mon, 17 Jun 2019 17:40:23 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 2081B286BD; Mon, 17 Jun 2019 17:40:23 +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 A6D0C26E73 for ; Mon, 17 Jun 2019 17:40:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728571AbfFQRkW (ORCPT ); Mon, 17 Jun 2019 13:40:22 -0400 Received: from hqemgate15.nvidia.com ([216.228.121.64]:17047 "EHLO hqemgate15.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726593AbfFQRkW (ORCPT ); Mon, 17 Jun 2019 13:40:22 -0400 Received: from hqpgpgate101.nvidia.com (Not Verified[216.228.121.13]) by hqemgate15.nvidia.com (using TLS: TLSv1.2, DES-CBC3-SHA) id ; Mon, 17 Jun 2019 10:40:20 -0700 Received: from hqmail.nvidia.com ([172.20.161.6]) by hqpgpgate101.nvidia.com (PGP Universal service); Mon, 17 Jun 2019 10:40:19 -0700 X-PGP-Universal: processed; by hqpgpgate101.nvidia.com on Mon, 17 Jun 2019 10:40:19 -0700 Received: from HQMAIL108.nvidia.com (172.18.146.13) by HQMAIL106.nvidia.com (172.18.146.12) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Mon, 17 Jun 2019 17:40:19 +0000 Received: from manikanta-bm2.nvidia.com (10.124.1.5) by HQMAIL108.nvidia.com (172.18.146.13) with Microsoft SMTP Server id 15.0.1473.3 via Frontend Transport; Mon, 17 Jun 2019 17:40:16 +0000 From: Manikanta Maddireddy To: , , , , , , CC: , , , Manikanta Maddireddy Subject: [PATCH V5 06/27] PCI: tegra: Add PCIe Gen2 link speed support Date: Mon, 17 Jun 2019 23:09:31 +0530 Message-ID: <20190617173952.29363-7-mmaddireddy@nvidia.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190617173952.29363-1-mmaddireddy@nvidia.com> References: <20190617173952.29363-1-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=1560793220; bh=I9g8S6i36JLsfwSYH2wGAHJGoGPyGwTF6SFjzPUpsOo=; h=X-PGP-Universal:From:To:CC:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:X-NVConfidentiality:MIME-Version: Content-Type; b=J3b0kCMuh42UpAaVIonDqrZBwcXf1a5UuJ8hN1B+NtKAOB2YHWzLIsZjZfQwj2x8q Cw5za4syOyLtOH3+hrseX7LbiSDtVk3St60jvV3R8YWD+86mGdZ/EAYKiACXc7NQ9e MVYIaCA4Mhkq3hnjsYLy1oiy6ZxAFnwTW/nVXZpLNSl1pdU9Sko3hqDPT1M6gi0+X+ fAkcp8G6cueUhE0JPTOKTCmx7JO4TDrGOrfnD9/MWM/za4AAtrWKQTs6eNr1nJLjMw tFgdpu01w/mRQxgkdZo7/IN020QGcyYy8lSeTCgbHVou4JKlVZ2XcfEg1zhWSkTB1b jSlVO4vn/ik0g== 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 --- V5: No change 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 5e9fcef5f8eb..5d19067f7193 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)