Re: [PATCH V10 03/15] PCI: dwc: Perform dbi regs write lock towards the end
From: Jingoo Han <jingoohan1@gmail.com>
Date: 2019-06-18 06:42:45
Also in:
linux-devicetree, linux-pci, linux-tegra, lkml
On 6/12/19, 6:54 PM, Vidya Sagar wrote:
Remove multiple write enable and disable sequences of dbi registers as Tegra194 implements writes to BAR-0 register (offset: 0x10) controlled by DBI write-lock enable bit thereby not allowing any further writes to BAR-0 register in config space to take place. Hence enabling write permission at the start of function and disabling the same only towards the end. Signed-off-by: Vidya Sagar <redacted> Reviewed-by: Thierry Reding <redacted>
Acked-by: Jingoo Han <jingoohan1@gmail.com> Sorry for being late. I read the previous threads. I don't think that this patch has any harmful effects. This patch looks good to me. Thank you. Best regards, Jingoo Han
quoted hunk ↗ jump to hunk
--- Changes since [v9]: * None Changes since [v8]: * None Changes since [v7]: * None Changes since [v6]: * None Changes since [v5]: * Moved write enable to the beginning of the API and write disable to the end Changes since [v4]: * None Changes since [v3]: * None Changes since [v2]: * None Changes since [v1]: * None 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 f93252d0da5b..d3156446ff27 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);-- 2.17.1
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