From patchwork Thu Mar 31 12:03:02 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dimitri John Ledkov X-Patchwork-Id: 1611715 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: bilbo.ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=canonical.com header.i=@canonical.com header.a=rsa-sha256 header.s=20210705 header.b=JwnLr6dt; dkim-atps=neutral Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=lists.ubuntu.com (client-ip=91.189.94.19; helo=huckleberry.canonical.com; envelope-from=kernel-team-bounces@lists.ubuntu.com; receiver=) Received: from huckleberry.canonical.com (huckleberry.canonical.com [91.189.94.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by bilbo.ozlabs.org (Postfix) with ESMTPS id 4KThlW57G8z9sCq for ; Thu, 31 Mar 2022 23:03:19 +1100 (AEDT) Received: from localhost ([127.0.0.1] helo=huckleberry.canonical.com) by huckleberry.canonical.com with esmtp (Exim 4.86_2) (envelope-from ) id 1nZtWE-0003Zm-JG; Thu, 31 Mar 2022 12:03:14 +0000 Received: from smtp-relay-internal-0.internal ([10.131.114.225] helo=smtp-relay-internal-0.canonical.com) by huckleberry.canonical.com with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.86_2) (envelope-from ) id 1nZtWC-0003Z8-C7 for kernel-team@lists.ubuntu.com; Thu, 31 Mar 2022 12:03:12 +0000 Received: from mail-ej1-f70.google.com (mail-ej1-f70.google.com [209.85.218.70]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by smtp-relay-internal-0.canonical.com (Postfix) with ESMTPS id 5B7DB3F6FA for ; Thu, 31 Mar 2022 12:03:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=canonical.com; s=20210705; t=1648728191; bh=YgthxTu6yycTm7jWQzkwp1WZTBX7SLtJq3O6F/sl7bE=; h=From:To:Subject:Date:Message-Id:MIME-Version; b=JwnLr6dtNncYpIIFFiPOtYL/u2MWioR/8yfDhfsORrnDVaFPK/TwHyJcIZl4+yaV2 PWJlb+B14ROf7X6sGHhhk2kK9UBjyl2JRjt+G+i90y4wA+3togfFKf5T/QShGDWP1u 0mMAoXUJO6v0Jc4jSNRiq9ZXubRak2HHGXm2AHbue3UFmlmYdNUxl7NhqEQvW6RgTE qnakQEcuGeRGkkW/XobpSIPGVYcPuVa7MUNQlfbGgsnPRB7lPrzWB+2OHpqtjRL3sc I/jtVWVYXGmypIZWrGM5ziH94Ogu3blcvHPzMkkHkdP52JZyPV8SVQ417NWMbZ2UEW pnk/dkhcabsvw== Received: by mail-ej1-f70.google.com with SMTP id er8-20020a170907738800b006e003254d86so11410914ejc.11 for ; Thu, 31 Mar 2022 05:03:11 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:subject:date:message-id:mime-version :content-transfer-encoding; bh=YgthxTu6yycTm7jWQzkwp1WZTBX7SLtJq3O6F/sl7bE=; b=LvVpx5LzzhvVZPZdtXjLleXEz7awDUv0Q6+5p8PsXmeymca0VOmpVoW+3PeoXGrNi/ 7Rn8DKvRuIRUGHtJgwLqfcFOy9XElRvpKmphMF1DUm+cUuV1hoD2LISpBN8Y9Qv2y554 mn0JWugLnqajNrBPTZoBQd2/47pkYh+zkQ9sBYaZoayg6x/AmgbywZdDe+3RjPIMn3FF wqmOHPz6uuR0Bjn35Nrm5H7IQHDLHWc3/Kp1ElMCO3yJ8nNfoo4ZcZNO2tL8sBLUoKWc zucQcG/ley8dlXyIll9BnCbGkR/DQDnK3T6DoF0vMDoouNmsFXxRhzUXS3diJ1jOoEaG PWNQ== X-Gm-Message-State: AOAM5326VtNahG5SXWaPG+/TSGbV5FLn0iZ8L8F0bsDLPa19dInBv9xe uIZF3Z+zWkEZbMnbEOqVDP/Rbd9uVkVhHDoNBWf5TxF8NQUU8x2K/sgGlub6Y9LWm9s/EZsbTEE 6qmZavTKH7XtJdF5qZxT7kBDtQrsHI6fvr6kAWWctaA== X-Received: by 2002:a05:6402:2711:b0:419:5a50:75ef with SMTP id y17-20020a056402271100b004195a5075efmr16423806edd.280.1648728190294; Thu, 31 Mar 2022 05:03:10 -0700 (PDT) X-Google-Smtp-Source: ABdhPJx7kD5a1YjU6vh2zBtrZMGvtL+8awWrMANz+dDJC2lEjxyrTVu0ifewhpSduRb5MKHojwCM8g== X-Received: by 2002:a05:6402:2711:b0:419:5a50:75ef with SMTP id y17-20020a056402271100b004195a5075efmr16423770edd.280.1648728189924; Thu, 31 Mar 2022 05:03:09 -0700 (PDT) Received: from localhost ([2001:67c:1560:8007::aac:c15c]) by smtp.gmail.com with ESMTPSA id nc7-20020a1709071c0700b006dfe66694dasm9846999ejc.144.2022.03.31.05.03.08 for (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 31 Mar 2022 05:03:09 -0700 (PDT) From: Dimitri John Ledkov To: kernel-team@lists.ubuntu.com Subject: [J/linux-riscv][PATCH] PCI: fu740: Force 2.5GT/s for initial device probe Date: Thu, 31 Mar 2022 13:03:02 +0100 Message-Id: <20220331120302.118803-1-dimitri.ledkov@canonical.com> X-Mailer: git-send-email 2.32.0 MIME-Version: 1.0 X-BeenThere: kernel-team@lists.ubuntu.com X-Mailman-Version: 2.1.20 Precedence: list List-Id: Kernel team discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: kernel-team-bounces@lists.ubuntu.com Sender: "kernel-team" From: Ben Dooks The fu740 PCIe core does not probe any devices on the SiFive Unmatched board without this fix (or having U-Boot explicitly start the PCIe via either boot-script or user command). The fix is to start the link at 2.5GT/s speeds and once the link is up then change the maximum speed back to the default. The U-Boot driver claims to set the link-speed to 2.5GT/s to get the probe to work (and U-Boot does print link up at 2.5GT/s) in the following code: https://source.denx.de/u-boot/u-boot/-/blob/master/drivers/pci/pcie_dw_sifive.c?id=v2022.01#L271 Link: https://lore.kernel.org/r/20220318152430.526320-1-ben.dooks@codethink.co.uk Signed-off-by: Ben Dooks Signed-off-by: Bjorn Helgaas Acked-by: Palmer Dabbelt (cherry picked from commit a382c757ec5ef83137a86125f43a4c43dc2ab50b) Link: https://lore.kernel.org/stable/20220331115345.117662-1-dimitri.ledkov@canonical.com/T/#u BugLink: https://bugs.launchpad.net/bugs/1964796 Signed-off-by: Dimitri John Ledkov Acked-by: Tim Gardner --- drivers/pci/controller/dwc/pcie-fu740.c | 51 ++++++++++++++++++++++++- 1 file changed, 50 insertions(+), 1 deletion(-) diff --git a/drivers/pci/controller/dwc/pcie-fu740.c b/drivers/pci/controller/dwc/pcie-fu740.c index 00cde9a248..78d002be4f 100644 --- a/drivers/pci/controller/dwc/pcie-fu740.c +++ b/drivers/pci/controller/dwc/pcie-fu740.c @@ -181,10 +181,59 @@ static int fu740_pcie_start_link(struct dw_pcie *pci) { struct device *dev = pci->dev; struct fu740_pcie *afp = dev_get_drvdata(dev); + u8 cap_exp = dw_pcie_find_capability(pci, PCI_CAP_ID_EXP); + int ret; + u32 orig, tmp; + + /* + * Force 2.5GT/s when starting the link, due to some devices not + * probing at higher speeds. This happens with the PCIe switch + * on the Unmatched board when U-Boot has not initialised the PCIe. + * The fix in U-Boot is to force 2.5GT/s, which then gets cleared + * by the soft reset done by this driver. + */ + dev_dbg(dev, "cap_exp at %x\n", cap_exp); + dw_pcie_dbi_ro_wr_en(pci); + + tmp = dw_pcie_readl_dbi(pci, cap_exp + PCI_EXP_LNKCAP); + orig = tmp & PCI_EXP_LNKCAP_SLS; + tmp &= ~PCI_EXP_LNKCAP_SLS; + tmp |= PCI_EXP_LNKCAP_SLS_2_5GB; + dw_pcie_writel_dbi(pci, cap_exp + PCI_EXP_LNKCAP, tmp); /* Enable LTSSM */ writel_relaxed(0x1, afp->mgmt_base + PCIEX8MGMT_APP_LTSSM_ENABLE); - return 0; + + ret = dw_pcie_wait_for_link(pci); + if (ret) { + dev_err(dev, "error: link did not start\n"); + goto err; + } + + tmp = dw_pcie_readl_dbi(pci, cap_exp + PCI_EXP_LNKCAP); + if ((tmp & PCI_EXP_LNKCAP_SLS) != orig) { + dev_dbg(dev, "changing speed back to original\n"); + + tmp &= ~PCI_EXP_LNKCAP_SLS; + tmp |= orig; + dw_pcie_writel_dbi(pci, cap_exp + PCI_EXP_LNKCAP, tmp); + + tmp = dw_pcie_readl_dbi(pci, PCIE_LINK_WIDTH_SPEED_CONTROL); + tmp |= PORT_LOGIC_SPEED_CHANGE; + dw_pcie_writel_dbi(pci, PCIE_LINK_WIDTH_SPEED_CONTROL, tmp); + + ret = dw_pcie_wait_for_link(pci); + if (ret) { + dev_err(dev, "error: link did not start at new speed\n"); + goto err; + } + } + + ret = 0; +err: + WARN_ON(ret); /* we assume that errors will be very rare */ + dw_pcie_dbi_ro_wr_dis(pci); + return ret; } static int fu740_pcie_host_init(struct pcie_port *pp)