From patchwork Mon Feb 14 08:21:44 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ben Dooks X-Patchwork-Id: 12745266 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 C04AAC433F5 for ; Mon, 14 Feb 2022 09:08:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242603AbiBNJI7 (ORCPT ); Mon, 14 Feb 2022 04:08:59 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:57892 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234743AbiBNJI6 (ORCPT ); Mon, 14 Feb 2022 04:08:58 -0500 X-Greylist: delayed 1799 seconds by postgrey-1.37 at lindbergh.monkeyblade.net; Mon, 14 Feb 2022 01:08:50 PST Received: from imap2.colo.codethink.co.uk (imap2.colo.codethink.co.uk [78.40.148.184]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AD41E59A72; Mon, 14 Feb 2022 01:08:50 -0800 (PST) Received: from [167.98.27.226] (helo=rainbowdash) by imap2.colo.codethink.co.uk with esmtpsa (Exim 4.92 #3 (Debian)) id 1nJWcK-0000ZS-DI; Mon, 14 Feb 2022 08:21:52 +0000 Received: from ben by rainbowdash with local (Exim 4.95) (envelope-from ) id 1nJWcG-004vz6-3u; Mon, 14 Feb 2022 08:21:48 +0000 From: Ben Dooks To: linux-kernel@vger.kernel.org, bhelgaas@google.comv, linux-pci@vger.kernel.org Cc: paul.walmsley@sifive.com, greentime.hu@sifive.com, david.abdurachmanov@gmail.com, Ben Dooks Subject: [PATCH 2/2] PCI: fu740: Force gen1 for initial device probe Date: Mon, 14 Feb 2022 08:21:44 +0000 Message-Id: <20220214082144.1176084-3-ben.dooks@codethink.co.uk> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220214082144.1176084-1-ben.dooks@codethink.co.uk> References: <20220214082144.1176084-1-ben.dooks@codethink.co.uk> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org The fu740 dw pcie core does not probe devices without this fix from U-boot. The fix claims to set the link-speed to gen1 to get the probe to work. As this is a copy from U-boot, the commentary is assumed to be correct. Without this in, and without U-boot starting the PCIe the Unmatched board does not show any PCIe devices after the DW root port. Signed-off-by: Ben Dooks --- drivers/pci/controller/dwc/pcie-fu740.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) diff --git a/drivers/pci/controller/dwc/pcie-fu740.c b/drivers/pci/controller/dwc/pcie-fu740.c index 842b7202b96e..19501ec8c487 100644 --- a/drivers/pci/controller/dwc/pcie-fu740.c +++ b/drivers/pci/controller/dwc/pcie-fu740.c @@ -177,11 +177,30 @@ static void fu740_pcie_init_phy(struct fu740_pcie *afp) fu740_phyregwrite(1, PCIEX8MGMT_PHY_LANE3_BASE, PCIEX8MGMT_PHY_INIT_VAL, afp); } +/* This is copied from u-boot. Force system to gen1 otherwise nothing probes + * as found on the SiFive Unmatched board. + */ +static void fu740_pcie_force_gen1(struct dw_pcie *dw, struct fu740_pcie *afp ) +{ + unsigned val; + + dw_pcie_dbi_ro_wr_en(dw); + + val = dw_pcie_readl_dbi(dw, 0x70 + PCI_EXP_LNKCAP); + pr_info("%s: link-cap was %08x\n", __func__, val); + dw_pcie_writel_dbi(dw, 0x70 + PCI_EXP_LNKCAP, val | 0xf); + + dw_pcie_dbi_ro_wr_dis(dw); +} + static int fu740_pcie_start_link(struct dw_pcie *pci) { struct device *dev = pci->dev; struct fu740_pcie *afp = dev_get_drvdata(dev); + /* Force PCIe gen1 otherwise Unmatched board does not probe */ + fu740_pcie_force_gen1(pci, afp); + /* Enable LTSSM */ writel_relaxed(0x1, afp->mgmt_base + PCIEX8MGMT_APP_LTSSM_ENABLE); return 0;