From 118a533b58c291b4862c49f6a54272a48ff44870 Mon Sep 17 00:00:00 2001 From: Baikal Electronics Date: Fri, 24 Jun 2022 17:34:19 +0300 Subject: [PATCH] PCI: dwc: Simplify unrolled iATU detection The unrolled version of the internal ATU has been available since the DWC PCIe v4.80a IP core, but it may not be enabled. Per [1], if unrolled ATU is enabled, the PCIE_ATU_VIEWPORT does not exist and reads as 0xffffffff; while if unrolled ATU is disabled, PCIE_ATU_VIEWPORT will contain some zeros. Simplify dw_pcie_iatu_unroll_enabled() by checking the value of PCIE_ATU_VIEWPORT. [1] DesignWare Cores, PCI Express Controller, Register Desciptions, v.4.90a, December 2016, p.855 [bhelgaas: commit log] Link: https://lore.kernel.org/r/20220624143428.8334-10-Sergey.Semin@baikalelectronics.ru Tested-by: Manivannan Sadhasivam Signed-off-by: Serge Semin Signed-off-by: Bjorn Helgaas Reviewed-by: Manivannan Sadhasivam Reviewed-by: Rob Herring --- drivers/pci/controller/dwc/pcie-designware.c | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-) diff --git a/drivers/pci/controller/dwc/pcie-designware.c b/drivers/pci/controller/dwc/pcie-designware.c index ac966ed28c5bc..e5c30695f664c 100644 --- a/drivers/pci/controller/dwc/pcie-designware.c +++ b/drivers/pci/controller/dwc/pcie-designware.c @@ -600,15 +600,15 @@ static void dw_pcie_link_set_max_speed(struct dw_pcie *pci, u32 link_gen) } -static u8 dw_pcie_iatu_unroll_enabled(struct dw_pcie *pci) +static bool dw_pcie_iatu_unroll_enabled(struct dw_pcie *pci) { u32 val; val = dw_pcie_readl_dbi(pci, PCIE_ATU_VIEWPORT); if (val == 0xffffffff) - return 1; + return true; - return 0; + return false; } static void dw_pcie_iatu_detect_regions_unroll(struct dw_pcie *pci) @@ -680,9 +680,8 @@ void dw_pcie_iatu_detect(struct dw_pcie *pci) struct device *dev = pci->dev; struct platform_device *pdev = to_platform_device(dev); - if (pci->version >= 0x480A || (!pci->version && - dw_pcie_iatu_unroll_enabled(pci))) { - pci->iatu_unroll_enabled = true; + pci->iatu_unroll_enabled = dw_pcie_iatu_unroll_enabled(pci); + if (pci->iatu_unroll_enabled) { if (!pci->atu_base) { struct resource *res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "atu"); -- 2.39.5