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PCI: imx6: Set PCIE_DBI_RO_WR_EN before writing DBI registers

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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 <hongxing.zhu@nxp.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
This commit is contained in:
Richard Zhu 2022-05-18 17:35:27 +08:00 committed by Bjorn Helgaas
parent 835a345b18
commit 13f8f3d1e3
1 changed files with 4 additions and 0 deletions
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4
drivers/pci/controller/dwc/pci-imx6.c
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@ -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) {