[PATCH 00/20] PCI: fix config and I/O Address space memory mappings

Lorenzo Pieralisi
2017-02-27T15:15:43Z

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@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Jingoo Han <jingoohan1@gmail.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Mingkai Hu <mingkai.hu@freescale.com>
Cc: Tanmay Inamdar <tinamdar@apm.com>
Cc: Murali Karicheri <m-karicheri2@ti.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Bharat Kumar Gogada <bharat.kumar.gogada@xilinx.com>
Cc: Ray Jui <rjui@broadcom.com>
Cc: Wenrui Li <wenrui.li@rock-chips.com>
Cc: Shawn Lin <shawn.lin@rock-chips.com>
Cc: Minghuan Lian <minghuan.Lian@freescale.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Jon Mason <jonmason@broadcom.com>
Cc: Gabriele Paoloni <gabriele.paoloni@huawei.com>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: Joao Pinto <Joao.Pinto@synopsys.com>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Michal Simek <michal.simek@xilinx.com>
Cc: Stanimir Varbanov <svarbanov@mm-sol.com>
Cc: Zhou Wang <wangzhou1@hisilicon.com>
Cc: Roy Zang <tie-fei.zang@freescale.com>

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(-)

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2.10.0