[PATCH v4 00/21] PCI: fix config space memory mappings

Lorenzo Pieralisi lorenzo.pieralisi at arm.com
Wed Apr 19 09:48:49 PDT 2017

This patch series[1] is a v4 of a previous version:

v3 -> v4:
	- Reverted back to pci_remap_cfgspace() interface for lack of
	  consensus on ioremap_nopost() semantics
	- Dropped pci_remap_iospace() rework (owing to lack of adequate
	  pgprot_* attribute description across arches)
	- Updated pci_remap_cfgspace() comments

v3: http://lists.infradead.org/pipermail/linux-arm-kernel/2017-April/500838.html

v2 -> v3:
	- Created a default ioremap_nopost() implementation in a separate
	  asm-generic header and patched all arches to make use of it
	- Removed PCI drivers patches from the series to simplify the
	  review, they will be posted separately once the ioremap_nopost()
	  interface is settled
	- Fixed devm_ioremap_* BUS offset comments and implemented
	  nopost interface on top of it
	- Added collected tags

v2: https://lkml.org/lkml/2017/3/27/220

v2 -> v3:
	- Fixed devm_ioremap_* BUS offset comments and implemented
	  nopost interface on top of it
	- Added collected tags

v1: https://lkml.org/lkml/2017/2/27/228

v1 -> v2:
	- Changed pci_remap_cfgspace() to more generic ioremap_nopost()
	- Added pgprot_nonposted
	- Fixed build errors on arches not relying on asm-generic headers
	- Added PCI versatile host controller driver patch
	- Added missing config space remapping to hisilicon host controller

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

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-v4

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

Lorenzo Pieralisi (21):
  PCI: remove __weak tag from pci_remap_iospace()
  linux/io.h: add PCI config space remap interface
  ARM64: implement pci_remap_cfgspace() interface
  ARM: implement pci_remap_cfgspace() interface
  lib: fix Devres devm_ioremap_* offset parameter kerneldoc description
  PCI: implement Devres interface to map PCI config space
  PCI: ECAM: use pci_remap_cfgspace() to map config region
  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: 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: hisi: update PCI config space remap function
  PCI: layerscape: update PCI config space remap function
  PCI: keystone-dw: update PCI config space remap function
  PCI: versatile: 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/arm/mm/nommu.c                    | 12 +++++
 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            |  7 ++-
 drivers/pci/dwc/pcie-qcom.c            |  2 +-
 drivers/pci/dwc/pcie-spear13xx.c       |  2 +-
 drivers/pci/ecam.c                     |  6 ++-
 drivers/pci/host/pci-tegra.c           |  4 +-
 drivers/pci/host/pci-versatile.c       |  3 +-
 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                      | 84 +++++++++++++++++++++++++++++++++-
 include/linux/io.h                     | 19 ++++++++
 include/linux/pci.h                    |  5 ++
 lib/devres.c                           |  6 +--
 24 files changed, 183 insertions(+), 31 deletions(-)


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