From 13f8f3d1e369f56dfaeea10a2238d56bc36c876c Mon Sep 17 00:00:00 2001 From: Richard Zhu Date: Wed, 18 May 2022 17:35:27 +0800 Subject: [PATCH] PCI: imx6: Set PCIE_DBI_RO_WR_EN before writing DBI registers The PCIE_DBI_RO_WR_EN bit should be set when write some DBI registers. To make sure that the DBI registers are writable, set the PCIE_DBI_RO_WR_EN properly when writing the DBI registers. Link: https://lore.kernel.org/r/1652866528-13220-1-git-send-email-hongxing.zhu@nxp.com Signed-off-by: Richard Zhu Signed-off-by: Bjorn Helgaas --- drivers/pci/controller/dwc/pci-imx6.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c index 81ab6ddb0d59..d11032388d23 100644 --- a/drivers/pci/controller/dwc/pci-imx6.c +++ b/drivers/pci/controller/dwc/pci-imx6.c @@ -830,10 +830,12 @@ static int imx6_pcie_start_link(struct dw_pcie *pci) * started in Gen2 mode, there is a possibility the devices on the * bus will not be detected at all. This happens with PCIe switches. */ + dw_pcie_dbi_ro_wr_en(pci); tmp = dw_pcie_readl_dbi(pci, offset + PCI_EXP_LNKCAP); tmp &= ~PCI_EXP_LNKCAP_SLS; tmp |= PCI_EXP_LNKCAP_SLS_2_5GB; dw_pcie_writel_dbi(pci, offset + PCI_EXP_LNKCAP, tmp); + dw_pcie_dbi_ro_wr_dis(pci); /* Start LTSSM. */ imx6_pcie_ltssm_enable(dev); @@ -844,6 +846,7 @@ static int imx6_pcie_start_link(struct dw_pcie *pci) if (pci->link_gen == 2) { /* Allow Gen2 mode after the link is up. */ + dw_pcie_dbi_ro_wr_en(pci); tmp = dw_pcie_readl_dbi(pci, offset + PCI_EXP_LNKCAP); tmp &= ~PCI_EXP_LNKCAP_SLS; tmp |= PCI_EXP_LNKCAP_SLS_5_0GB; @@ -856,6 +859,7 @@ static int imx6_pcie_start_link(struct dw_pcie *pci) 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); + dw_pcie_dbi_ro_wr_dis(pci); if (imx6_pcie->drvdata->flags & IMX6_PCIE_FLAG_IMX6_SPEED_CHANGE) {