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 <[email protected]> Cc: Arnd Bergmann <[email protected]> Cc: Jonathan Corbet <[email protected]> Cc: Will Deacon <[email protected]> Cc: Jingoo Han <[email protected]> Cc: Bjorn Helgaas <[email protected]> Cc: Mingkai Hu <[email protected]> Cc: Tanmay Inamdar <[email protected]> Cc: Murali Karicheri <[email protected]> Cc: Russell King <[email protected]> Cc: Bharat Kumar Gogada <[email protected]> Cc: Ray Jui <[email protected]> Cc: Wenrui Li <[email protected]> Cc: Shawn Lin <[email protected]> Cc: Minghuan Lian <[email protected]> Cc: Catalin Marinas <[email protected]> Cc: Jon Mason <[email protected]> Cc: Gabriele Paoloni <[email protected]> Cc: Thomas Petazzoni <[email protected]> Cc: Joao Pinto <[email protected]> Cc: Thierry Reding <[email protected]> Cc: Michal Simek <[email protected]> Cc: Stanimir Varbanov <[email protected]> Cc: Zhou Wang <[email protected]> Cc: Roy Zang <[email protected]> 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
