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

From: Bjorn Helgaas
Date: Thu Apr 20 2017 - 09:26:15 EST


On Wed, Apr 19, 2017 at 05:48:49PM +0100, Lorenzo Pieralisi wrote:
> This patch series[1] is a v4 of a previous version:

Applied to pci/ioremap for v4.12, thanks, Lorenzo!

> 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()
> interface
> - 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
> 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-v4
>
> 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: Luis R. Rodriguez <mcgrof@xxxxxxxxxx>
> 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 (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(-)
>
> --
> 2.10.0
>
>
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