From 3924bc2fd1b607faa5cb0bc0655e9853656de31a Mon Sep 17 00:00:00 2001 From: Vidya Sagar Date: Tue, 13 Aug 2019 17:06:17 +0530 Subject: [PATCH] PCI: dwc: Group DBI registers writes requiring unlocking Some of DesignWare core's DBI registers (a.k.a configuration space registers) are write-protected with a lock without enabling which they are read-only by default. These write-protected registers are implementation specific. Tegra194's BAR-0 register which is at offset 0x10 in the configuration space is an example. Current implementation in dw_pcie_setup_rc() API attempts to unlock those write-protected registers whenever they are updated and lock them back again for writing. Group all write-protected registers writes so that locking and unlocking is performed once to avoid bloating the code with multiple unlock/lock sequences for all those write-protected registers. Signed-off-by: Vidya Sagar Signed-off-by: Lorenzo Pieralisi Reviewed-by: Thierry Reding Acked-by: Jingoo Han --- drivers/pci/controller/dwc/pcie-designware-host.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c index f93252d..d315644 100644 --- a/drivers/pci/controller/dwc/pcie-designware-host.c +++ b/drivers/pci/controller/dwc/pcie-designware-host.c @@ -628,6 +628,12 @@ void dw_pcie_setup_rc(struct pcie_port *pp) u32 val, ctrl, num_ctrls; struct dw_pcie *pci = to_dw_pcie_from_pp(pp); + /* + * Enable DBI read-only registers for writing/updating configuration. + * Write permission gets disabled towards the end of this function. + */ + dw_pcie_dbi_ro_wr_en(pci); + dw_pcie_setup(pci); if (!pp->ops->msi_host_init) { @@ -650,12 +656,10 @@ void dw_pcie_setup_rc(struct pcie_port *pp) dw_pcie_writel_dbi(pci, PCI_BASE_ADDRESS_1, 0x00000000); /* Setup interrupt pins */ - dw_pcie_dbi_ro_wr_en(pci); val = dw_pcie_readl_dbi(pci, PCI_INTERRUPT_LINE); val &= 0xffff00ff; val |= 0x00000100; dw_pcie_writel_dbi(pci, PCI_INTERRUPT_LINE, val); - dw_pcie_dbi_ro_wr_dis(pci); /* Setup bus numbers */ val = dw_pcie_readl_dbi(pci, PCI_PRIMARY_BUS); @@ -687,15 +691,13 @@ void dw_pcie_setup_rc(struct pcie_port *pp) dw_pcie_wr_own_conf(pp, PCI_BASE_ADDRESS_0, 4, 0); - /* Enable write permission for the DBI read-only register */ - dw_pcie_dbi_ro_wr_en(pci); /* Program correct class for RC */ dw_pcie_wr_own_conf(pp, PCI_CLASS_DEVICE, 2, PCI_CLASS_BRIDGE_PCI); - /* Better disable write permission right after the update */ - dw_pcie_dbi_ro_wr_dis(pci); dw_pcie_rd_own_conf(pp, PCIE_LINK_WIDTH_SPEED_CONTROL, 4, &val); val |= PORT_LOGIC_SPEED_CHANGE; dw_pcie_wr_own_conf(pp, PCIE_LINK_WIDTH_SPEED_CONTROL, 4, val); + + dw_pcie_dbi_ro_wr_dis(pci); } EXPORT_SYMBOL_GPL(dw_pcie_setup_rc); -- 2.7.4