From 43d324eeb08c3dd9fff7eb9a2c617afd3b96e65c Mon Sep 17 00:00:00 2001 From: Krishna Chaitanya Chundru Date: Tue, 27 Jan 2026 16:10:41 +0100 Subject: [PATCH] PCI: dwc: Fix missing iATU setup when ECAM is enabled When ECAM is enabled, the driver skipped calling dw_pcie_iatu_setup() before configuring ECAM iATU entries. This left IO and MEM outbound windows unprogrammed, resulting in broken IO transactions. Additionally, dw_pcie_config_ecam_iatu() was only called during host initialization, so ECAM-related iATU entries were not restored after suspend/resume, leading to failures in configuration space access To resolve these issues, move the ECAM iATU configuration to dw_pcie_iatu_setup(), and invoke dw_pcie_iatu_setup() when ECAM is enabled. Furthermore, add error checks in dw_pcie_prog_outbound_atu() and dw_pcie_prog_inbound_atu() such that an error is returned if the caller is trying to program an iATU that is outside the number of iATUs supported by the controller. Fixes: f6fd357f7afb ("PCI: dwc: Prepare the driver for enabling ECAM mechanism using iATU 'CFG Shift Feature'") Reported-by: Maciej W. Rozycki Closes: https://lore.kernel.org/all/alpine.DEB.2.21.2511280256260.36486@angie.orcam.me.uk/ Signed-off-by: Krishna Chaitanya Chundru Co-developed-by: Niklas Cassel Signed-off-by: Niklas Cassel [mani: used imperative tone] Signed-off-by: Manivannan Sadhasivam Tested-by: Maciej W. Rozycki Reviewed-by: Damien Le Moal Reviewed-by: Hans Zhang Reviewed-by: Frank Li Cc: stable+noautosel@kernel.org # depends on Clean up iATU index usage in dw_pcie_iatu_setup() Link: https://patch.msgid.link/20260127151038.1484881-8-cassel@kernel.org --- .../pci/controller/dwc/pcie-designware-host.c | 33 ++++++++++++------- drivers/pci/controller/dwc/pcie-designware.c | 6 ++++ 2 files changed, 28 insertions(+), 11 deletions(-) diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c index 87e6a32dbb9a..bc2e08ec515e 100644 --- a/drivers/pci/controller/dwc/pcie-designware-host.c +++ b/drivers/pci/controller/dwc/pcie-designware-host.c @@ -641,14 +641,6 @@ int dw_pcie_host_init(struct dw_pcie_rp *pp) if (ret) goto err_free_msi; - if (pp->ecam_enabled) { - ret = dw_pcie_config_ecam_iatu(pp); - if (ret) { - dev_err(dev, "Failed to configure iATU in ECAM mode\n"); - goto err_free_msi; - } - } - /* * Allocate the resource for MSG TLP before programming the iATU * outbound window in dw_pcie_setup_rc(). Since the allocation depends @@ -915,8 +907,21 @@ static int dw_pcie_iatu_setup(struct dw_pcie_rp *pp) * NOTE: For outbound address translation, outbound iATU at index 0 is * reserved for CFG IOs (dw_pcie_other_conf_map_bus()), thus start at * index 1. + * + * If using ECAM, outbound iATU at index 0 and index 1 is reserved for + * CFG IOs. */ - ob_iatu_index = 1; + if (pp->ecam_enabled) { + ob_iatu_index = 2; + ret = dw_pcie_config_ecam_iatu(pp); + if (ret) { + dev_err(pci->dev, "Failed to configure iATU in ECAM mode\n"); + return ret; + } + } else { + ob_iatu_index = 1; + } + resource_list_for_each_entry(entry, &pp->bridge->windows) { resource_size_t res_size; @@ -985,8 +990,14 @@ static int dw_pcie_iatu_setup(struct dw_pcie_rp *pp) * be shared between I/O space and CFG IOs, by * temporarily reconfiguring the iATU to CFG space, in * order to do a CFG IO, and then immediately restoring - * it to I/O space. + * it to I/O space. This is only implemented when using + * dw_pcie_other_conf_map_bus(), which is not the case + * when using ECAM. */ + if (pp->ecam_enabled) { + dev_err(pci->dev, "Cannot add outbound window for I/O\n"); + return -ENOMEM; + } pp->cfg0_io_shared = true; } } @@ -1157,7 +1168,7 @@ int dw_pcie_setup_rc(struct dw_pcie_rp *pp) * the platform uses its own address translation component rather than * ATU, so we should not program the ATU here. */ - if (pp->bridge->child_ops == &dw_child_pcie_ops) { + if (pp->bridge->child_ops == &dw_child_pcie_ops || pp->ecam_enabled) { ret = dw_pcie_iatu_setup(pp); if (ret) return ret; diff --git a/drivers/pci/controller/dwc/pcie-designware.c b/drivers/pci/controller/dwc/pcie-designware.c index 18331d9e85be..5741c09dde7f 100644 --- a/drivers/pci/controller/dwc/pcie-designware.c +++ b/drivers/pci/controller/dwc/pcie-designware.c @@ -532,6 +532,9 @@ int dw_pcie_prog_outbound_atu(struct dw_pcie *pci, u32 retries, val; u64 limit_addr; + if (atu->index >= pci->num_ob_windows) + return -ENOSPC; + limit_addr = parent_bus_addr + atu->size - 1; if ((limit_addr & ~pci->region_limit) != (parent_bus_addr & ~pci->region_limit) || @@ -605,6 +608,9 @@ int dw_pcie_prog_inbound_atu(struct dw_pcie *pci, int index, int type, u64 limit_addr = pci_addr + size - 1; u32 retries, val; + if (index >= pci->num_ib_windows) + return -ENOSPC; + if ((limit_addr & ~pci->region_limit) != (pci_addr & ~pci->region_limit) || !IS_ALIGNED(parent_bus_addr, pci->region_align) || !IS_ALIGNED(pci_addr, pci->region_align) || !size) { -- 2.47.3