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From:   Andy Shevchenko <andy.shevchenko@gmail.com>
Date:   Tue, 20 Feb 2018 16:54:32 +0200
Message-ID: <CAHp75VeFiQocuedW64ePgLO=_FQd7Q_hX-+wMh0zec3XUzhVxw@mail.gmail.com>
Subject: Re: [PATCH v14 0/9] LPC: legacy ISA I/O support
To:     John Garry <john.garry@huawei.com>
Cc:     Mika Westerberg <mika.westerberg@linux.intel.com>,
        "Rafael J. Wysocki" <rafael@kernel.org>,
        Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
        "Rafael J. Wysocki" <rjw@rjwysocki.net>,
        Hanjun Guo <hanjun.guo@linaro.org>,
        Rob Herring <robh+dt@kernel.org>,
        Bjorn Helgaas <bhelgaas@google.com>,
        Arnd Bergmann <arnd@arndb.de>,
        Mark Rutland <mark.rutland@arm.com>,
        Olof Johansson <olof@lixom.net>,
        Dann Frazier <dann.frazier@canonical.com>,
        Rob Herring <robh@kernel.org>, Joe Perches <joe@perches.com>,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        linux-pci@vger.kernel.org,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        ACPI Devel Maling List <linux-acpi@vger.kernel.org>,
        Linuxarm <linuxarm@huawei.com>, Corey Minyard <minyard@acm.org>,
        devicetree <devicetree@vger.kernel.org>,
        Linux-Arch <linux-arch@vger.kernel.org>,
        Randy Dunlap <rdunlap@infradead.org>
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On Mon, Feb 19, 2018 at 7:48 PM, John Garry <john.garry@huawei.com> wrote:
> This patchset supports the IPMI-bt device attached to the Low-Pin-Count
> interface implemented on Hisilicon Hip06/Hip07 SoC.
>                         -----------
>                         | LPC host|
>                         |         |
>                         -----------
>                              |
>                 _____________V_______________LPC
>                   |                       |
>                   V                       V
>                                      ------------
>                                      |  BT(ipmi)|
>                                      ------------
>
> When master accesses those peripherals beneath the Hip06/Hip07 LPC, a specific
> LPC driver is needed to make LPC host generate the standard LPC I/O cycles with
> the target peripherals'I/O port addresses. But on curent arm64 world, there is
> no real I/O accesses. All the I/O operations through in/out accessors are based
> on MMIO ranges; on Hip06/Hip07 LPC the I/O accesses are performed through driver
> specific accessors rather than MMIO.
> To solve this issue and keep the relevant existing peripherals' drivers untouched,
> this patchset:
>    - introduces a generic I/O space management framework, logical PIO, to support
>       I/O operations on host controllers operating either on MMIO buses or on buses
>      requiring specific driver I/O accessors;
>    - redefines the in/out accessors to provide a unified interface for both MMIO
>      and driver specific I/O operations. Using logical PIO, th call of in/out() from
>      the host children drivers, such as ipmi-si, will be redirected to the
>      corresponding device-specific I/O hooks to perform the I/O accesses.
>
> Based on this patch-set, all the I/O accesses to Hip06/Hip07 LPC peripherals can
> be supported without any changes on the existing ipmi-si driver.
>
> The whole patchset has been tested on Hip07 D05 board both using DTB and ACPI.
>
> Differences to v13:
> - dropped ACPI scan handler and added patch to not enumerate children
>   of indirect IO hosts in ACPI code
> - tidied up logic_pio.c a bit for kerneldoc and made some APIs clearer
>   to understand
> - tided (and simplified) hisi_lpc.c and added new ACPI probe code
>   (same as previous ACPI scan handler code, so comments from Rafael
>   and Andy included)
> - reinstated PCI range upper limit check in pci_pio_to_address()
> - dropped Dann Frazier's "tested-by" tag in light of changes
> - rebase to linuxnext 20180219 (had to fix locally arm64 build issue)
>

Some minor comments per patches, otherwise FWIW

Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>

> Differences to v12:
>     - Addressed ACPI comments from Rafael and Andy, including:
>      - added SPDX license identifiers (other new files in the series got this also)
>      - fixed style issues, like superflous newlines and symbol naming
>      - add fuller acpi_indirectio.c patch commit message
>      - dropped acpi_indirectio_host_data (author's decision) to simplify
>     - added Rob Herring's tag
>     - rebase to linux-next 20180212
>
> Differences to v11:
>     - fixed build errors for i386, m68k, and tile
>     - added a comment in LPC driver commit log why we set
>        the kernel config as bool
>     - some tidying logic_pio code
>
> Differences to v10:
>     - dropped CONFIG_LOGIC_PIO. Reason is that CONFIG_PCI
>       depends on this, and CONFIG_PCI is a per-arch CONFIG.
>       So we would require all arch's kconfig to select this.
>     - Addressed Dann Frazier's comments on LPC driver, and
>       sopme other cleanup
>     - Moved logic_pio.h to be included in generic asm io.h
>     - Fixed ACPI indirect IO host setup to handle >1 child
>     - Relocated ACPI indirect IO host setup code to
>       drivers/acpi
>     - Rebased to linux next-20180118
>
> Changes from v9:
>   - patch 2 has been split into 3 patches according to Bjorn comments on
>     v9 thread
>   - patch 1 has been reworked accordign to Bjorn comments on v9
>   - now logic_pio_trans_hwaddr() has a sanity check to make sure the resource
>     size fits into the assigned range
>   - in patch 5 the MFD framework has been used to probe the LPC children
>     according to the suggestion from Mika Westerberg
>   - Maintaner has changed to Huawei Linuxarm mailing list
>
> Changes from v8:
>   - Simplified LIB IO framewrok
>   - Moved INDIRECT PIO ACPI framework under acpi/arm64
>   - Renamed occurrences of "lib io" and "indirect io" to "lib pio" and
>     "indirect pio" to keep the patchset nomenclature consistent
>   - Removed Alignment reuqirements
>   - Moved LPC specific code out of ACPI common framework
>   - Now PIO indirect HW ranges can overlap
>   - Changed HiSilicon LPC driver maintainer (Gabriele Paoloni now) and split
>     maintaner file modifications in a separate commit
>   - Removed the commit with the DT nodes support for hip06 and hip07 (to be
>     pushed separately)
>   - Added a checking on ioport_map() not to break that function as Arnd points
>     out in V7 review thread;
>   - fixed the compile issues on alpha, m68k;
>
> Changes from V7:
>   - Based on Arnd's comment, rename the LIBIO as LOGIC_PIO;
>   - Improved the mapping process in LOGIC_PIO to gain better efficiency when
>     redirecting the I/O accesses to right device driver;
>   - To reduce the impact on PCI MMIO to a minimum, add a new
>     CONFIG_INDIRECT_PIO for indirect-IO hosts/devices;
>   - Added a new ACPI handler for indirect-IO hosts/devices;
>   - Fixed the compile issues on V6;
>
> Changes from V6:
>   - According to the comments from Bjorn and Alex, merge PCI IO and indirect-IO
>     into a generic I/O space management, LIBIO;
>   - Adopted the '_DEP' to replace the platform bus notifier. In this way, we can
>     ensure the LPC peripherals' I/O resources had been translated to logical IO
>     before the LPC peripheral enumeration;
>   - Replaced the rwlock with rcu list based on Alex's suggestion;
>   - Applied relaxed write/read to LPC driver;
>   - Some bugs fixing and some optimazations based on the comments of V6;
>
> Changes from V5:
>   - Made the extio driver more generic and locate in lib/;
>   - Supported multiple indirect-IO bus instances;
>   - Extended the pci_register_io_range() to support indirect-IO, then dropped
>   the I/O reservation used in previous patchset;
>   - Reimplemented the ACPI LPC support;
>   - Fixed some bugs, including the compile error on other archs, the module
>   building failure found by Ming Lei, etc;
>
> Changes from V4:
>   - Some revises based on the comments from Bjorn, Rob on V4;
>   - Fixed the compile error on some platforms, such as openrisc;
>
> Changes from V3:
>   - UART support deferred to a separate patchset; This patchset only support
>   ipmi device under LPC;
>   - LPC bus I/O range is fixed to 0 ~ (PCIBIOS_MIN_IO - 1), which is separeted
>   from PCI/PCIE PIO space;
>   - Based on Arnd's remarks, removed the ranges property from Hip06 lpc dts and
>   added a new fixup function, of_isa_indirect_io(), to get the I/O address
>   directly from LPC dts configurations;
>   - Support in(w,l)/out(w,l) for Hip06 lpc I/O;
>   - Decouple the header file dependency on the gerenic io.h by defining in/out
>   as normal functions in c file;
>   - removed unused macro definitions in the LPC driver;
>
> Changes from V2:
>   - Support the PIO retrieval from the linux PIO generated by
>   pci_address_to_pio. This method replace the 4K PIO reservation in V2;
>   - Support the flat-tree earlycon;
>   - Some revises based on Arnd's remarks;
>   - Make sure the linux PIO range allocated to Hip06 LPC peripherals starts
>   from non-ZERO;
>
> Changes from V1:
>   - Support the ACPI LPC device;
>   - Optimize the dts LPC driver in ISA compatible mode;
>   - Reserve the IO range below 4K in avoid the possible conflict with PCI host
>   IO ranges;
>   - Support the LPC uart and relevant earlycon;
>
> V13 thread here: https://lkml.org/lkml/2018/2/13/744
> V12 thread here: https://lkml.org/lkml/2018/1/23/508
> V11 thread here: https://lkml.org/lkml/2018/1/21/38
> V10 thread here: https://lkml.org/lkml/2017/10/27/465
> V9 thread here: https://lkml.org/lkml/2017/5/25/263
> V8 thread here: https://lkml.org/lkml/2017/3/30/619
> V7 thread here: https://lkml.org/lkml/2017/3/12/279
> v6 thread here: https://lkml.org/lkml/2017/1/24/25
> v5 thread here: https://lkml.org/lkml/2016/11/7/955
> v4 thread here: https://lkml.org/lkml/2016/10/20/149
> v3 thread here: https://lkml.org/lkml/2016/9/14/326
> v2 thread here: https://lkml.org/lkml/2016/9/7/356
> v1 thread here: https://lkml.org/lkml/2015/12/29/154
>
> Gabriele Paoloni (2):
>   PCI: Remove unused __weak attribute in pci_register_io_range()
>   PCI: Add fwnode handler as input param of pci_register_io_range()
>
> John Garry (3):
>   ACPI / scan: do not enumerate Indirect IO host children
>   HISI LPC: Add ACPI support
>   MAINTAINERS: Add maintainer for HiSilicon LPC driver
>
> Zhichang Yuan (4):
>   LIB: Introduce a generic PIO mapping method
>   PCI: Apply the new generic I/O management on PCI IO hosts
>   OF: Add missing I/O range exception for indirect-IO devices
>   HISI LPC: Support the LPC host on Hip06/Hip07 with DT bindings
>
>  .../arm/hisilicon/hisilicon-low-pin-count.txt      |  33 ++
>  MAINTAINERS                                        |   7 +
>  drivers/acpi/pci_root.c                            |   8 +-
>  drivers/acpi/scan.c                                |  14 +
>  drivers/bus/Kconfig                                |   8 +
>  drivers/bus/Makefile                               |   1 +
>  drivers/bus/hisi_lpc.c                             | 646 +++++++++++++++++++++
>  drivers/of/address.c                               |  96 ++-
>  drivers/pci/pci.c                                  |  95 +--
>  include/asm-generic/io.h                           |   4 +-
>  include/linux/logic_pio.h                          | 131 +++++
>  include/linux/pci.h                                |   3 +-
>  lib/Kconfig                                        |  15 +
>  lib/Makefile                                       |   2 +
>  lib/logic_pio.c                                    | 285 +++++++++
>  15 files changed, 1250 insertions(+), 98 deletions(-)
>  create mode 100644 Documentation/devicetree/bindings/arm/hisilicon/hisilicon-low-pin-count.txt
>  create mode 100644 drivers/bus/hisi_lpc.c
>  create mode 100644 include/linux/logic_pio.h
>  create mode 100644 lib/logic_pio.c
>
> --
> 1.9.1
>


-- 
With Best Regards,
Andy Shevchenko