PCI local bus specifications (Rev3.0, 3.2.5 "Transaction Ordering and Posting") strictly require PCI configuration and I/O Address space write transactions to be non-posted. Current crop of DT/ACPI PCI host controllers drivers relies on the ioremap interface to map ECAM and ECAM-derivative PCI config regions and pci_remap_iospace() to create a VMA for mapping PCI host bridge I/O Address space transactions to CPU virtual address space. On some platforms (ie ARM/ARM64) ioremap fails to comply with the PCI configuration non-posted write transactions requirement, because it provides a memory mapping that issues "bufferable" or, in PCI terms "posted" write transactions. Likewise, the current pci_remap_iospace() implementation maps the physical address range that the PCI translates to I/O space cycles to virtual address space through pgprot_device() attributes that on eg ARM64 provides a memory mapping issuing posted writes transactions, which is not PCI specifications compliant. This patch series[1] addresses both issues in one go: - It updates the pci_remap_iospace() function to use a page mapping that guarantees non-posted write transactions for I/O space addresses - It adds a kernel API to remap PCI config space resources, so that architecture can override it with a mapping implementation that guarantees PCI specifications compliancy wrt non-posted write configuration transactions - It updates all PCI host controller implementations (and the generic ECAM layer) to use the newly introduced mapping interface Tested on Juno ECAM based interface (DT/ACPI). Non-ECAM PCI host controller drivers patches need checking to make sure that: - I patched the correct resource region mapping for config space - There are not any other ways to ensure posted-write completion in the respective pci_ops that make the relevant patch unnecessary [1] git://git.kernel.org/pub/scm/linux/kernel/git/lpieralisi/linux.git pci/config-io-mappings-fix Cc: Pratyush Anand <pratyush.anand@xxxxxxxxx> Cc: Arnd Bergmann <arnd@xxxxxxxx> Cc: Jonathan Corbet <corbet@xxxxxxx> Cc: Will Deacon <will.deacon@xxxxxxx> Cc: Jingoo Han <jingoohan1@xxxxxxxxx> Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx> Cc: Mingkai Hu <mingkai.hu@xxxxxxxxxxxxx> Cc: Tanmay Inamdar <tinamdar@xxxxxxx> Cc: Murali Karicheri <m-karicheri2@xxxxxx> Cc: Russell King <linux@xxxxxxxxxxxxxxx> Cc: Bharat Kumar Gogada <bharat.kumar.gogada@xxxxxxxxxx> Cc: Ray Jui <rjui@xxxxxxxxxxxx> Cc: Wenrui Li <wenrui.li@xxxxxxxxxxxxxx> Cc: Shawn Lin <shawn.lin@xxxxxxxxxxxxxx> Cc: Minghuan Lian <minghuan.Lian@xxxxxxxxxxxxx> Cc: Catalin Marinas <catalin.marinas@xxxxxxx> Cc: Jon Mason <jonmason@xxxxxxxxxxxx> Cc: Gabriele Paoloni <gabriele.paoloni@xxxxxxxxxx> Cc: Thomas Petazzoni <thomas.petazzoni@xxxxxxxxxxxxxxxxxx> Cc: Joao Pinto <Joao.Pinto@xxxxxxxxxxxx> Cc: Thierry Reding <thierry.reding@xxxxxxxxx> Cc: Michal Simek <michal.simek@xxxxxxxxxx> Cc: Stanimir Varbanov <svarbanov@xxxxxxxxxx> Cc: Zhou Wang <wangzhou1@xxxxxxxxxxxxx> Cc: Roy Zang <tie-fei.zang@xxxxxxxxxxxxx> Lorenzo Pieralisi (20): PCI: remove __weak tag from pci_remap_iospace() PCI: fix pci_remap_iospace() remap attribute asm-generic/io.h: add PCI config space remap interface ARM64: implement pci_remap_cfgspace() interface ARM: implement pci_remap_cfgspace() interface PCI: ECAM: use pci_remap_cfgspace() to map config region PCI: implement Devres interface to map PCI config space PCI: xilinx: update PCI config space remap function PCI: xilinx-nwl: update PCI config space remap function PCI: spear13xx: update PCI config space remap function PCI: rockchip: update PCI config space remap function PCI: qcom: update PCI config space remap function PCI: iproc-platform: update PCI config space remap function PCI: hisi: update PCI config space remap function PCI: designware: update PCI config space remap function PCI: armada8k: update PCI config space remap function PCI: xgene: update PCI config space remap function PCI: tegra: update PCI config space remap function PCI: layerscape: update PCI config space remap function PCI: keystone-dw: update PCI config space remap function Documentation/driver-model/devres.txt | 6 ++- arch/arm/include/asm/io.h | 10 ++++ arch/arm/mm/ioremap.c | 7 +++ arch/arm64/include/asm/io.h | 10 ++++ drivers/pci/dwc/pci-keystone-dw.c | 2 +- drivers/pci/dwc/pci-layerscape.c | 2 +- drivers/pci/dwc/pcie-armada8k.c | 2 +- drivers/pci/dwc/pcie-designware-host.c | 12 +++-- drivers/pci/dwc/pcie-hisi.c | 3 +- drivers/pci/dwc/pcie-qcom.c | 2 +- drivers/pci/dwc/pcie-spear13xx.c | 2 +- drivers/pci/ecam.c | 5 +- drivers/pci/host/pci-tegra.c | 4 +- drivers/pci/host/pci-xgene.c | 4 +- drivers/pci/host/pcie-iproc-platform.c | 3 +- drivers/pci/host/pcie-rockchip.c | 2 +- drivers/pci/host/pcie-xilinx-nwl.c | 2 +- drivers/pci/host/pcie-xilinx.c | 2 +- drivers/pci/pci.c | 86 +++++++++++++++++++++++++++++++++- include/asm-generic/io.h | 9 ++++ include/linux/pci.h | 5 ++ 21 files changed, 154 insertions(+), 26 deletions(-) -- 2.10.0
