From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from metis.ext.pengutronix.de ([92.198.50.35]:34571 "EHLO metis.ext.pengutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751087AbaBLH2Q (ORCPT ); Wed, 12 Feb 2014 02:28:16 -0500 From: Sascha Hauer To: linux-pci@vger.kernel.org Cc: kernel@pengutronix.de, Sascha Hauer , Richard Zhu , Shawn Guo , Bjorn Helgaas , linux-arm-kernel@lists.infradead.org, Marek Vasut Subject: [PATCH] PCI: imx6: Fix link_up detection Date: Wed, 12 Feb 2014 08:27:55 +0100 Message-Id: <1392190075-23204-1-git-send-email-s.hauer@pengutronix.de> Sender: linux-pci-owner@vger.kernel.org List-ID: This is broken since: | commit e6daf4a5e1b813bc7f85507ec83b8c2452c121e6 | Author: Marek Vasut | Date: Thu Dec 12 22:49:59 2013 +0100 | | PCI: imx6: Report "link up" only after link training completes | | While waiting for the PHY to report the PCIe link is up, we might hit a | situation where the link training is still in progress, while the PHY | already reports the link is up. Add additional check for this condition. | | Signed-off-by: Marek Vasut | Signed-off-by: Bjorn Helgaas | Acked-by: Shawn Guo The problem is: Before the above commit only the PCIE_PHY_DEBUG_R1_XMLH_LINK_UP bit was used to determine whether the link is up or not. Since the above commit also the PCIE_PHY_DEBUG_R1_XMLH_LINK_IN_TRAINING is used. This means a link still being trained is as link down. The designware driver changes the PORT_LOGIC_SPEED_CHANGE bit in dw_pcie_host_init() which causes the link to be retrained. During the next call to dw_pcie_rd_conf() the link is then reported being down and the function returns PCIBIOS_DEVICE_NOT_FOUND resulting in nonfunctioning PCIe. This patch fixes this by waiting until the link training has finished before testing the PCIE_PHY_DEBUG_R1_XMLH_LINK_UP bit. This is hardly the correct solution, but I don't know what should be done instead. Signed-off-by: Sascha Hauer Cc: Richard Zhu (maintainer:PCI DRIVER FOR IMX6) Cc: Shawn Guo (maintainer:PCI DRIVER FOR IMX6) Cc: Bjorn Helgaas (supporter:PCI SUBSYSTEM) Cc: linux-pci@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org Cc: Marek Vasut --- drivers/pci/host/pci-imx6.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/drivers/pci/host/pci-imx6.c b/drivers/pci/host/pci-imx6.c index 866bdc7..9b6b501 100644 --- a/drivers/pci/host/pci-imx6.c +++ b/drivers/pci/host/pci-imx6.c @@ -449,6 +449,7 @@ static void imx6_pcie_reset_phy(struct pcie_port *pp) static int imx6_pcie_link_up(struct pcie_port *pp) { u32 rc, ltssm, rx_valid; + int count = 1000; /* * Test if the PHY reports that the link is up and also that @@ -458,8 +459,13 @@ static int imx6_pcie_link_up(struct pcie_port *pp) * as well here. */ rc = readl(pp->dbi_base + PCIE_PHY_DEBUG_R1); - if ((rc & PCIE_PHY_DEBUG_R1_XMLH_LINK_UP) && - !(rc & PCIE_PHY_DEBUG_R1_XMLH_LINK_IN_TRAINING)) + while (rc & PCIE_PHY_DEBUG_R1_XMLH_LINK_IN_TRAINING) { + if (!count--) + return 0; + rc = readl(pp->dbi_base + PCIE_PHY_DEBUG_R1); + } + + if (rc & PCIE_PHY_DEBUG_R1_XMLH_LINK_UP) return 1; /* -- 1.8.5.3